Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 2954e4b..ffc3e53 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1,19 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
* Copyright (c) 2016 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
+ * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
*/
+#include <uapi/linux/btf.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/bpf.h>
+#include <linux/btf.h>
#include <linux/bpf_verifier.h>
#include <linux/filter.h>
#include <net/netlink.h>
@@ -23,6 +18,7 @@
#include <linux/bsearch.h>
#include <linux/sort.h>
#include <linux/perf_event.h>
+#include <linux/ctype.h>
#include "disasm.h"
@@ -80,8 +76,8 @@
* (like pointer plus pointer becomes SCALAR_VALUE type)
*
* When verifier sees load or store instructions the type of base register
- * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK. These are three pointer
- * types recognized by check_mem_access() function.
+ * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
+ * four pointer types recognized by check_mem_access() function.
*
* PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
* and the range of [ptr, ptr + map's value_size) is accessible.
@@ -140,6 +136,24 @@
*
* After the call R0 is set to return type of the function and registers R1-R5
* are set to NOT_INIT to indicate that they are no longer readable.
+ *
+ * The following reference types represent a potential reference to a kernel
+ * resource which, after first being allocated, must be checked and freed by
+ * the BPF program:
+ * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
+ *
+ * When the verifier sees a helper call return a reference type, it allocates a
+ * pointer id for the reference and stores it in the current function state.
+ * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
+ * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
+ * passes through a NULL-check conditional. For the branch wherein the state is
+ * changed to CONST_IMM, the verifier releases the reference.
+ *
+ * For each helper function that allocates a reference, such as
+ * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
+ * bpf_sk_release(). When a reference type passes into the release function,
+ * the verifier also releases the reference. If any unchecked or unreleased
+ * reference remains at the end of the program, the verifier rejects it.
*/
/* verifier_state + insn_idx are pushed to stack when branch is encountered */
@@ -154,8 +168,8 @@
struct bpf_verifier_stack_elem *next;
};
-#define BPF_COMPLEXITY_LIMIT_INSNS 131072
-#define BPF_COMPLEXITY_LIMIT_STACK 1024
+#define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192
+#define BPF_COMPLEXITY_LIMIT_STATES 64
#define BPF_MAP_PTR_UNPRIV 1UL
#define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \
@@ -189,10 +203,33 @@
int access_size;
s64 msize_smax_value;
u64 msize_umax_value;
+ int ref_obj_id;
+ int func_id;
};
static DEFINE_MUTEX(bpf_verifier_lock);
+static const struct bpf_line_info *
+find_linfo(const struct bpf_verifier_env *env, u32 insn_off)
+{
+ const struct bpf_line_info *linfo;
+ const struct bpf_prog *prog;
+ u32 i, nr_linfo;
+
+ prog = env->prog;
+ nr_linfo = prog->aux->nr_linfo;
+
+ if (!nr_linfo || insn_off >= prog->len)
+ return NULL;
+
+ linfo = prog->aux->linfo;
+ for (i = 1; i < nr_linfo; i++)
+ if (insn_off < linfo[i].insn_off)
+ break;
+
+ return &linfo[i - 1];
+}
+
void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt,
va_list args)
{
@@ -243,12 +280,105 @@
va_end(args);
}
+static const char *ltrim(const char *s)
+{
+ while (isspace(*s))
+ s++;
+
+ return s;
+}
+
+__printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env,
+ u32 insn_off,
+ const char *prefix_fmt, ...)
+{
+ const struct bpf_line_info *linfo;
+
+ if (!bpf_verifier_log_needed(&env->log))
+ return;
+
+ linfo = find_linfo(env, insn_off);
+ if (!linfo || linfo == env->prev_linfo)
+ return;
+
+ if (prefix_fmt) {
+ va_list args;
+
+ va_start(args, prefix_fmt);
+ bpf_verifier_vlog(&env->log, prefix_fmt, args);
+ va_end(args);
+ }
+
+ verbose(env, "%s\n",
+ ltrim(btf_name_by_offset(env->prog->aux->btf,
+ linfo->line_off)));
+
+ env->prev_linfo = linfo;
+}
+
static bool type_is_pkt_pointer(enum bpf_reg_type type)
{
return type == PTR_TO_PACKET ||
type == PTR_TO_PACKET_META;
}
+static bool type_is_sk_pointer(enum bpf_reg_type type)
+{
+ return type == PTR_TO_SOCKET ||
+ type == PTR_TO_SOCK_COMMON ||
+ type == PTR_TO_TCP_SOCK ||
+ type == PTR_TO_XDP_SOCK;
+}
+
+static bool reg_type_may_be_null(enum bpf_reg_type type)
+{
+ return type == PTR_TO_MAP_VALUE_OR_NULL ||
+ type == PTR_TO_SOCKET_OR_NULL ||
+ type == PTR_TO_SOCK_COMMON_OR_NULL ||
+ type == PTR_TO_TCP_SOCK_OR_NULL;
+}
+
+static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
+{
+ return reg->type == PTR_TO_MAP_VALUE &&
+ map_value_has_spin_lock(reg->map_ptr);
+}
+
+static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
+{
+ return type == PTR_TO_SOCKET ||
+ type == PTR_TO_SOCKET_OR_NULL ||
+ type == PTR_TO_TCP_SOCK ||
+ type == PTR_TO_TCP_SOCK_OR_NULL;
+}
+
+static bool arg_type_may_be_refcounted(enum bpf_arg_type type)
+{
+ return type == ARG_PTR_TO_SOCK_COMMON;
+}
+
+/* Determine whether the function releases some resources allocated by another
+ * function call. The first reference type argument will be assumed to be
+ * released by release_reference().
+ */
+static bool is_release_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_sk_release;
+}
+
+static bool is_acquire_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_sk_lookup_tcp ||
+ func_id == BPF_FUNC_sk_lookup_udp ||
+ func_id == BPF_FUNC_skc_lookup_tcp;
+}
+
+static bool is_ptr_cast_function(enum bpf_func_id func_id)
+{
+ return func_id == BPF_FUNC_tcp_sock ||
+ func_id == BPF_FUNC_sk_fullsock;
+}
+
/* string representation of 'enum bpf_reg_type' */
static const char * const reg_type_str[] = {
[NOT_INIT] = "?",
@@ -261,17 +391,35 @@
[PTR_TO_PACKET] = "pkt",
[PTR_TO_PACKET_META] = "pkt_meta",
[PTR_TO_PACKET_END] = "pkt_end",
+ [PTR_TO_FLOW_KEYS] = "flow_keys",
+ [PTR_TO_SOCKET] = "sock",
+ [PTR_TO_SOCKET_OR_NULL] = "sock_or_null",
+ [PTR_TO_SOCK_COMMON] = "sock_common",
+ [PTR_TO_SOCK_COMMON_OR_NULL] = "sock_common_or_null",
+ [PTR_TO_TCP_SOCK] = "tcp_sock",
+ [PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null",
+ [PTR_TO_TP_BUFFER] = "tp_buffer",
+ [PTR_TO_XDP_SOCK] = "xdp_sock",
+};
+
+static char slot_type_char[] = {
+ [STACK_INVALID] = '?',
+ [STACK_SPILL] = 'r',
+ [STACK_MISC] = 'm',
+ [STACK_ZERO] = '0',
};
static void print_liveness(struct bpf_verifier_env *env,
enum bpf_reg_liveness live)
{
- if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN))
+ if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE))
verbose(env, "_");
if (live & REG_LIVE_READ)
verbose(env, "r");
if (live & REG_LIVE_WRITTEN)
verbose(env, "w");
+ if (live & REG_LIVE_DONE)
+ verbose(env, "D");
}
static struct bpf_func_state *func(struct bpf_verifier_env *env,
@@ -299,14 +447,16 @@
verbose(env, " R%d", i);
print_liveness(env, reg->live);
verbose(env, "=%s", reg_type_str[t]);
+ if (t == SCALAR_VALUE && reg->precise)
+ verbose(env, "P");
if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
tnum_is_const(reg->var_off)) {
/* reg->off should be 0 for SCALAR_VALUE */
verbose(env, "%lld", reg->var_off.value + reg->off);
- if (t == PTR_TO_STACK)
- verbose(env, ",call_%d", func(env, reg)->callsite);
} else {
verbose(env, "(id=%d", reg->id);
+ if (reg_type_may_be_refcounted_or_null(t))
+ verbose(env, ",ref_obj_id=%d", reg->ref_obj_id);
if (t != SCALAR_VALUE)
verbose(env, ",off=%d", reg->off);
if (type_is_pkt_pointer(t))
@@ -349,72 +499,168 @@
}
}
for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
- if (state->stack[i].slot_type[0] == STACK_SPILL) {
- verbose(env, " fp%d",
- (-i - 1) * BPF_REG_SIZE);
- print_liveness(env, state->stack[i].spilled_ptr.live);
- verbose(env, "=%s",
- reg_type_str[state->stack[i].spilled_ptr.type]);
+ char types_buf[BPF_REG_SIZE + 1];
+ bool valid = false;
+ int j;
+
+ for (j = 0; j < BPF_REG_SIZE; j++) {
+ if (state->stack[i].slot_type[j] != STACK_INVALID)
+ valid = true;
+ types_buf[j] = slot_type_char[
+ state->stack[i].slot_type[j]];
}
- if (state->stack[i].slot_type[0] == STACK_ZERO)
- verbose(env, " fp%d=0", (-i - 1) * BPF_REG_SIZE);
+ types_buf[BPF_REG_SIZE] = 0;
+ if (!valid)
+ continue;
+ verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+ print_liveness(env, state->stack[i].spilled_ptr.live);
+ if (state->stack[i].slot_type[0] == STACK_SPILL) {
+ reg = &state->stack[i].spilled_ptr;
+ t = reg->type;
+ verbose(env, "=%s", reg_type_str[t]);
+ if (t == SCALAR_VALUE && reg->precise)
+ verbose(env, "P");
+ if (t == SCALAR_VALUE && tnum_is_const(reg->var_off))
+ verbose(env, "%lld", reg->var_off.value + reg->off);
+ } else {
+ verbose(env, "=%s", types_buf);
+ }
+ }
+ if (state->acquired_refs && state->refs[0].id) {
+ verbose(env, " refs=%d", state->refs[0].id);
+ for (i = 1; i < state->acquired_refs; i++)
+ if (state->refs[i].id)
+ verbose(env, ",%d", state->refs[i].id);
}
verbose(env, "\n");
}
-static int copy_stack_state(struct bpf_func_state *dst,
- const struct bpf_func_state *src)
-{
- if (!src->stack)
- return 0;
- if (WARN_ON_ONCE(dst->allocated_stack < src->allocated_stack)) {
- /* internal bug, make state invalid to reject the program */
- memset(dst, 0, sizeof(*dst));
- return -EFAULT;
- }
- memcpy(dst->stack, src->stack,
- sizeof(*src->stack) * (src->allocated_stack / BPF_REG_SIZE));
- return 0;
+#define COPY_STATE_FN(NAME, COUNT, FIELD, SIZE) \
+static int copy_##NAME##_state(struct bpf_func_state *dst, \
+ const struct bpf_func_state *src) \
+{ \
+ if (!src->FIELD) \
+ return 0; \
+ if (WARN_ON_ONCE(dst->COUNT < src->COUNT)) { \
+ /* internal bug, make state invalid to reject the program */ \
+ memset(dst, 0, sizeof(*dst)); \
+ return -EFAULT; \
+ } \
+ memcpy(dst->FIELD, src->FIELD, \
+ sizeof(*src->FIELD) * (src->COUNT / SIZE)); \
+ return 0; \
}
+/* copy_reference_state() */
+COPY_STATE_FN(reference, acquired_refs, refs, 1)
+/* copy_stack_state() */
+COPY_STATE_FN(stack, allocated_stack, stack, BPF_REG_SIZE)
+#undef COPY_STATE_FN
+
+#define REALLOC_STATE_FN(NAME, COUNT, FIELD, SIZE) \
+static int realloc_##NAME##_state(struct bpf_func_state *state, int size, \
+ bool copy_old) \
+{ \
+ u32 old_size = state->COUNT; \
+ struct bpf_##NAME##_state *new_##FIELD; \
+ int slot = size / SIZE; \
+ \
+ if (size <= old_size || !size) { \
+ if (copy_old) \
+ return 0; \
+ state->COUNT = slot * SIZE; \
+ if (!size && old_size) { \
+ kfree(state->FIELD); \
+ state->FIELD = NULL; \
+ } \
+ return 0; \
+ } \
+ new_##FIELD = kmalloc_array(slot, sizeof(struct bpf_##NAME##_state), \
+ GFP_KERNEL); \
+ if (!new_##FIELD) \
+ return -ENOMEM; \
+ if (copy_old) { \
+ if (state->FIELD) \
+ memcpy(new_##FIELD, state->FIELD, \
+ sizeof(*new_##FIELD) * (old_size / SIZE)); \
+ memset(new_##FIELD + old_size / SIZE, 0, \
+ sizeof(*new_##FIELD) * (size - old_size) / SIZE); \
+ } \
+ state->COUNT = slot * SIZE; \
+ kfree(state->FIELD); \
+ state->FIELD = new_##FIELD; \
+ return 0; \
+}
+/* realloc_reference_state() */
+REALLOC_STATE_FN(reference, acquired_refs, refs, 1)
+/* realloc_stack_state() */
+REALLOC_STATE_FN(stack, allocated_stack, stack, BPF_REG_SIZE)
+#undef REALLOC_STATE_FN
/* do_check() starts with zero-sized stack in struct bpf_verifier_state to
* make it consume minimal amount of memory. check_stack_write() access from
* the program calls into realloc_func_state() to grow the stack size.
* Note there is a non-zero 'parent' pointer inside bpf_verifier_state
- * which this function copies over. It points to previous bpf_verifier_state
- * which is never reallocated
+ * which realloc_stack_state() copies over. It points to previous
+ * bpf_verifier_state which is never reallocated.
*/
-static int realloc_func_state(struct bpf_func_state *state, int size,
- bool copy_old)
+static int realloc_func_state(struct bpf_func_state *state, int stack_size,
+ int refs_size, bool copy_old)
{
- u32 old_size = state->allocated_stack;
- struct bpf_stack_state *new_stack;
- int slot = size / BPF_REG_SIZE;
+ int err = realloc_reference_state(state, refs_size, copy_old);
+ if (err)
+ return err;
+ return realloc_stack_state(state, stack_size, copy_old);
+}
- if (size <= old_size || !size) {
- if (copy_old)
+/* Acquire a pointer id from the env and update the state->refs to include
+ * this new pointer reference.
+ * On success, returns a valid pointer id to associate with the register
+ * On failure, returns a negative errno.
+ */
+static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx)
+{
+ struct bpf_func_state *state = cur_func(env);
+ int new_ofs = state->acquired_refs;
+ int id, err;
+
+ err = realloc_reference_state(state, state->acquired_refs + 1, true);
+ if (err)
+ return err;
+ id = ++env->id_gen;
+ state->refs[new_ofs].id = id;
+ state->refs[new_ofs].insn_idx = insn_idx;
+
+ return id;
+}
+
+/* release function corresponding to acquire_reference_state(). Idempotent. */
+static int release_reference_state(struct bpf_func_state *state, int ptr_id)
+{
+ int i, last_idx;
+
+ last_idx = state->acquired_refs - 1;
+ for (i = 0; i < state->acquired_refs; i++) {
+ if (state->refs[i].id == ptr_id) {
+ if (last_idx && i != last_idx)
+ memcpy(&state->refs[i], &state->refs[last_idx],
+ sizeof(*state->refs));
+ memset(&state->refs[last_idx], 0, sizeof(*state->refs));
+ state->acquired_refs--;
return 0;
- state->allocated_stack = slot * BPF_REG_SIZE;
- if (!size && old_size) {
- kfree(state->stack);
- state->stack = NULL;
}
- return 0;
}
- new_stack = kmalloc_array(slot, sizeof(struct bpf_stack_state),
- GFP_KERNEL);
- if (!new_stack)
- return -ENOMEM;
- if (copy_old) {
- if (state->stack)
- memcpy(new_stack, state->stack,
- sizeof(*new_stack) * (old_size / BPF_REG_SIZE));
- memset(new_stack + old_size / BPF_REG_SIZE, 0,
- sizeof(*new_stack) * (size - old_size) / BPF_REG_SIZE);
- }
- state->allocated_stack = slot * BPF_REG_SIZE;
- kfree(state->stack);
- state->stack = new_stack;
+ return -EINVAL;
+}
+
+static int transfer_reference_state(struct bpf_func_state *dst,
+ struct bpf_func_state *src)
+{
+ int err = realloc_reference_state(dst, src->acquired_refs, false);
+ if (err)
+ return err;
+ err = copy_reference_state(dst, src);
+ if (err)
+ return err;
return 0;
}
@@ -422,10 +668,18 @@
{
if (!state)
return;
+ kfree(state->refs);
kfree(state->stack);
kfree(state);
}
+static void clear_jmp_history(struct bpf_verifier_state *state)
+{
+ kfree(state->jmp_history);
+ state->jmp_history = NULL;
+ state->jmp_history_cnt = 0;
+}
+
static void free_verifier_state(struct bpf_verifier_state *state,
bool free_self)
{
@@ -435,6 +689,7 @@
free_func_state(state->frame[i]);
state->frame[i] = NULL;
}
+ clear_jmp_history(state);
if (free_self)
kfree(state);
}
@@ -447,10 +702,14 @@
{
int err;
- err = realloc_func_state(dst, src->allocated_stack, false);
+ err = realloc_func_state(dst, src->allocated_stack, src->acquired_refs,
+ false);
if (err)
return err;
- memcpy(dst, src, offsetof(struct bpf_func_state, allocated_stack));
+ memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs));
+ err = copy_reference_state(dst, src);
+ if (err)
+ return err;
return copy_stack_state(dst, src);
}
@@ -458,15 +717,30 @@
const struct bpf_verifier_state *src)
{
struct bpf_func_state *dst;
+ u32 jmp_sz = sizeof(struct bpf_idx_pair) * src->jmp_history_cnt;
int i, err;
+ if (dst_state->jmp_history_cnt < src->jmp_history_cnt) {
+ kfree(dst_state->jmp_history);
+ dst_state->jmp_history = kmalloc(jmp_sz, GFP_USER);
+ if (!dst_state->jmp_history)
+ return -ENOMEM;
+ }
+ memcpy(dst_state->jmp_history, src->jmp_history, jmp_sz);
+ dst_state->jmp_history_cnt = src->jmp_history_cnt;
+
/* if dst has more stack frames then src frame, free them */
for (i = src->curframe + 1; i <= dst_state->curframe; i++) {
free_func_state(dst_state->frame[i]);
dst_state->frame[i] = NULL;
}
+ dst_state->speculative = src->speculative;
dst_state->curframe = src->curframe;
+ dst_state->active_spin_lock = src->active_spin_lock;
+ dst_state->branches = src->branches;
dst_state->parent = src->parent;
+ dst_state->first_insn_idx = src->first_insn_idx;
+ dst_state->last_insn_idx = src->last_insn_idx;
for (i = 0; i <= src->curframe; i++) {
dst = dst_state->frame[i];
if (!dst) {
@@ -482,6 +756,23 @@
return 0;
}
+static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+ while (st) {
+ u32 br = --st->branches;
+
+ /* WARN_ON(br > 1) technically makes sense here,
+ * but see comment in push_stack(), hence:
+ */
+ WARN_ONCE((int)br < 0,
+ "BUG update_branch_counts:branches_to_explore=%d\n",
+ br);
+ if (br)
+ break;
+ st = st->parent;
+ }
+}
+
static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx,
int *insn_idx)
{
@@ -510,7 +801,8 @@
}
static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
- int insn_idx, int prev_insn_idx)
+ int insn_idx, int prev_insn_idx,
+ bool speculative)
{
struct bpf_verifier_state *cur = env->cur_state;
struct bpf_verifier_stack_elem *elem;
@@ -528,10 +820,24 @@
err = copy_verifier_state(&elem->st, cur);
if (err)
goto err;
- if (env->stack_size > BPF_COMPLEXITY_LIMIT_STACK) {
- verbose(env, "BPF program is too complex\n");
+ elem->st.speculative |= speculative;
+ if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
+ verbose(env, "The sequence of %d jumps is too complex.\n",
+ env->stack_size);
goto err;
}
+ if (elem->st.parent) {
+ ++elem->st.parent->branches;
+ /* WARN_ON(branches > 2) technically makes sense here,
+ * but
+ * 1. speculative states will bump 'branches' for non-branch
+ * instructions
+ * 2. is_state_visited() heuristics may decide not to create
+ * a new state for a sequence of branches and all such current
+ * and cloned states will be pointing to a single parent state
+ * which might have large 'branches' count.
+ */
+ }
return &elem->st;
err:
free_verifier_state(env->cur_state, true);
@@ -705,7 +1011,11 @@
__mark_reg_not_init(regs + regno);
return;
}
- __mark_reg_unknown(regs + regno);
+ regs += regno;
+ __mark_reg_unknown(regs);
+ /* constant backtracking is enabled for root without bpf2bpf calls */
+ regs->precise = env->subprog_cnt > 1 || !env->allow_ptr_leaks ?
+ true : false;
}
static void __mark_reg_not_init(struct bpf_reg_state *reg)
@@ -727,6 +1037,7 @@
__mark_reg_not_init(regs + regno);
}
+#define DEF_NOT_SUBREG (0)
static void init_reg_state(struct bpf_verifier_env *env,
struct bpf_func_state *state)
{
@@ -736,6 +1047,8 @@
for (i = 0; i < MAX_BPF_REG; i++) {
mark_reg_not_init(env, regs, i);
regs[i].live = REG_LIVE_NONE;
+ regs[i].parent = NULL;
+ regs[i].subreg_def = DEF_NOT_SUBREG;
}
/* frame pointer */
@@ -827,10 +1140,6 @@
verbose(env, "function calls to other bpf functions are allowed for root only\n");
return -EPERM;
}
- if (bpf_prog_is_dev_bound(env->prog->aux)) {
- verbose(env, "function calls in offloaded programs are not supported yet\n");
- return -EINVAL;
- }
ret = add_subprog(env, i + insn[i].imm + 1);
if (ret < 0)
return ret;
@@ -841,7 +1150,7 @@
*/
subprog[env->subprog_cnt].start = insn_cnt;
- if (env->log.level > 1)
+ if (env->log.level & BPF_LOG_LEVEL2)
for (i = 0; i < env->subprog_cnt; i++)
verbose(env, "func#%d @%d\n", i, subprog[i].start);
@@ -851,7 +1160,7 @@
for (i = 0; i < insn_cnt; i++) {
u8 code = insn[i].code;
- if (BPF_CLASS(code) != BPF_JMP)
+ if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32)
goto next;
if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL)
goto next;
@@ -880,113 +1189,647 @@
return 0;
}
-static
-struct bpf_verifier_state *skip_callee(struct bpf_verifier_env *env,
- const struct bpf_verifier_state *state,
- struct bpf_verifier_state *parent,
- u32 regno)
-{
- struct bpf_verifier_state *tmp = NULL;
-
- /* 'parent' could be a state of caller and
- * 'state' could be a state of callee. In such case
- * parent->curframe < state->curframe
- * and it's ok for r1 - r5 registers
- *
- * 'parent' could be a callee's state after it bpf_exit-ed.
- * In such case parent->curframe > state->curframe
- * and it's ok for r0 only
- */
- if (parent->curframe == state->curframe ||
- (parent->curframe < state->curframe &&
- regno >= BPF_REG_1 && regno <= BPF_REG_5) ||
- (parent->curframe > state->curframe &&
- regno == BPF_REG_0))
- return parent;
-
- if (parent->curframe > state->curframe &&
- regno >= BPF_REG_6) {
- /* for callee saved regs we have to skip the whole chain
- * of states that belong to callee and mark as LIVE_READ
- * the registers before the call
- */
- tmp = parent;
- while (tmp && tmp->curframe != state->curframe) {
- tmp = tmp->parent;
- }
- if (!tmp)
- goto bug;
- parent = tmp;
- } else {
- goto bug;
- }
- return parent;
-bug:
- verbose(env, "verifier bug regno %d tmp %p\n", regno, tmp);
- verbose(env, "regno %d parent frame %d current frame %d\n",
- regno, parent->curframe, state->curframe);
- return NULL;
-}
-
+/* Parentage chain of this register (or stack slot) should take care of all
+ * issues like callee-saved registers, stack slot allocation time, etc.
+ */
static int mark_reg_read(struct bpf_verifier_env *env,
- const struct bpf_verifier_state *state,
- struct bpf_verifier_state *parent,
- u32 regno)
+ const struct bpf_reg_state *state,
+ struct bpf_reg_state *parent, u8 flag)
{
bool writes = parent == state->parent; /* Observe write marks */
-
- if (regno == BPF_REG_FP)
- /* We don't need to worry about FP liveness because it's read-only */
- return 0;
+ int cnt = 0;
while (parent) {
/* if read wasn't screened by an earlier write ... */
- if (writes && state->frame[state->curframe]->regs[regno].live & REG_LIVE_WRITTEN)
+ if (writes && state->live & REG_LIVE_WRITTEN)
break;
- parent = skip_callee(env, state, parent, regno);
- if (!parent)
+ if (parent->live & REG_LIVE_DONE) {
+ verbose(env, "verifier BUG type %s var_off %lld off %d\n",
+ reg_type_str[parent->type],
+ parent->var_off.value, parent->off);
return -EFAULT;
+ }
+ /* The first condition is more likely to be true than the
+ * second, checked it first.
+ */
+ if ((parent->live & REG_LIVE_READ) == flag ||
+ parent->live & REG_LIVE_READ64)
+ /* The parentage chain never changes and
+ * this parent was already marked as LIVE_READ.
+ * There is no need to keep walking the chain again and
+ * keep re-marking all parents as LIVE_READ.
+ * This case happens when the same register is read
+ * multiple times without writes into it in-between.
+ * Also, if parent has the stronger REG_LIVE_READ64 set,
+ * then no need to set the weak REG_LIVE_READ32.
+ */
+ break;
/* ... then we depend on parent's value */
- parent->frame[parent->curframe]->regs[regno].live |= REG_LIVE_READ;
+ parent->live |= flag;
+ /* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
+ if (flag == REG_LIVE_READ64)
+ parent->live &= ~REG_LIVE_READ32;
state = parent;
parent = state->parent;
writes = true;
+ cnt++;
}
+
+ if (env->longest_mark_read_walk < cnt)
+ env->longest_mark_read_walk = cnt;
return 0;
}
+/* This function is supposed to be used by the following 32-bit optimization
+ * code only. It returns TRUE if the source or destination register operates
+ * on 64-bit, otherwise return FALSE.
+ */
+static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn,
+ u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t)
+{
+ u8 code, class, op;
+
+ code = insn->code;
+ class = BPF_CLASS(code);
+ op = BPF_OP(code);
+ if (class == BPF_JMP) {
+ /* BPF_EXIT for "main" will reach here. Return TRUE
+ * conservatively.
+ */
+ if (op == BPF_EXIT)
+ return true;
+ if (op == BPF_CALL) {
+ /* BPF to BPF call will reach here because of marking
+ * caller saved clobber with DST_OP_NO_MARK for which we
+ * don't care the register def because they are anyway
+ * marked as NOT_INIT already.
+ */
+ if (insn->src_reg == BPF_PSEUDO_CALL)
+ return false;
+ /* Helper call will reach here because of arg type
+ * check, conservatively return TRUE.
+ */
+ if (t == SRC_OP)
+ return true;
+
+ return false;
+ }
+ }
+
+ if (class == BPF_ALU64 || class == BPF_JMP ||
+ /* BPF_END always use BPF_ALU class. */
+ (class == BPF_ALU && op == BPF_END && insn->imm == 64))
+ return true;
+
+ if (class == BPF_ALU || class == BPF_JMP32)
+ return false;
+
+ if (class == BPF_LDX) {
+ if (t != SRC_OP)
+ return BPF_SIZE(code) == BPF_DW;
+ /* LDX source must be ptr. */
+ return true;
+ }
+
+ if (class == BPF_STX) {
+ if (reg->type != SCALAR_VALUE)
+ return true;
+ return BPF_SIZE(code) == BPF_DW;
+ }
+
+ if (class == BPF_LD) {
+ u8 mode = BPF_MODE(code);
+
+ /* LD_IMM64 */
+ if (mode == BPF_IMM)
+ return true;
+
+ /* Both LD_IND and LD_ABS return 32-bit data. */
+ if (t != SRC_OP)
+ return false;
+
+ /* Implicit ctx ptr. */
+ if (regno == BPF_REG_6)
+ return true;
+
+ /* Explicit source could be any width. */
+ return true;
+ }
+
+ if (class == BPF_ST)
+ /* The only source register for BPF_ST is a ptr. */
+ return true;
+
+ /* Conservatively return true at default. */
+ return true;
+}
+
+/* Return TRUE if INSN doesn't have explicit value define. */
+static bool insn_no_def(struct bpf_insn *insn)
+{
+ u8 class = BPF_CLASS(insn->code);
+
+ return (class == BPF_JMP || class == BPF_JMP32 ||
+ class == BPF_STX || class == BPF_ST);
+}
+
+/* Return TRUE if INSN has defined any 32-bit value explicitly. */
+static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+ if (insn_no_def(insn))
+ return false;
+
+ return !is_reg64(env, insn, insn->dst_reg, NULL, DST_OP);
+}
+
+static void mark_insn_zext(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg)
+{
+ s32 def_idx = reg->subreg_def;
+
+ if (def_idx == DEF_NOT_SUBREG)
+ return;
+
+ env->insn_aux_data[def_idx - 1].zext_dst = true;
+ /* The dst will be zero extended, so won't be sub-register anymore. */
+ reg->subreg_def = DEF_NOT_SUBREG;
+}
+
static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
enum reg_arg_type t)
{
struct bpf_verifier_state *vstate = env->cur_state;
struct bpf_func_state *state = vstate->frame[vstate->curframe];
- struct bpf_reg_state *regs = state->regs;
+ struct bpf_insn *insn = env->prog->insnsi + env->insn_idx;
+ struct bpf_reg_state *reg, *regs = state->regs;
+ bool rw64;
if (regno >= MAX_BPF_REG) {
verbose(env, "R%d is invalid\n", regno);
return -EINVAL;
}
+ reg = ®s[regno];
+ rw64 = is_reg64(env, insn, regno, reg, t);
if (t == SRC_OP) {
/* check whether register used as source operand can be read */
- if (regs[regno].type == NOT_INIT) {
+ if (reg->type == NOT_INIT) {
verbose(env, "R%d !read_ok\n", regno);
return -EACCES;
}
- return mark_reg_read(env, vstate, vstate->parent, regno);
+ /* We don't need to worry about FP liveness because it's read-only */
+ if (regno == BPF_REG_FP)
+ return 0;
+
+ if (rw64)
+ mark_insn_zext(env, reg);
+
+ return mark_reg_read(env, reg, reg->parent,
+ rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32);
} else {
/* check whether register used as dest operand can be written to */
if (regno == BPF_REG_FP) {
verbose(env, "frame pointer is read only\n");
return -EACCES;
}
- regs[regno].live |= REG_LIVE_WRITTEN;
+ reg->live |= REG_LIVE_WRITTEN;
+ reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1;
if (t == DST_OP)
mark_reg_unknown(env, regs, regno);
}
return 0;
}
+/* for any branch, call, exit record the history of jmps in the given state */
+static int push_jmp_history(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *cur)
+{
+ u32 cnt = cur->jmp_history_cnt;
+ struct bpf_idx_pair *p;
+
+ cnt++;
+ p = krealloc(cur->jmp_history, cnt * sizeof(*p), GFP_USER);
+ if (!p)
+ return -ENOMEM;
+ p[cnt - 1].idx = env->insn_idx;
+ p[cnt - 1].prev_idx = env->prev_insn_idx;
+ cur->jmp_history = p;
+ cur->jmp_history_cnt = cnt;
+ return 0;
+}
+
+/* Backtrack one insn at a time. If idx is not at the top of recorded
+ * history then previous instruction came from straight line execution.
+ */
+static int get_prev_insn_idx(struct bpf_verifier_state *st, int i,
+ u32 *history)
+{
+ u32 cnt = *history;
+
+ if (cnt && st->jmp_history[cnt - 1].idx == i) {
+ i = st->jmp_history[cnt - 1].prev_idx;
+ (*history)--;
+ } else {
+ i--;
+ }
+ return i;
+}
+
+/* For given verifier state backtrack_insn() is called from the last insn to
+ * the first insn. Its purpose is to compute a bitmask of registers and
+ * stack slots that needs precision in the parent verifier state.
+ */
+static int backtrack_insn(struct bpf_verifier_env *env, int idx,
+ u32 *reg_mask, u64 *stack_mask)
+{
+ const struct bpf_insn_cbs cbs = {
+ .cb_print = verbose,
+ .private_data = env,
+ };
+ struct bpf_insn *insn = env->prog->insnsi + idx;
+ u8 class = BPF_CLASS(insn->code);
+ u8 opcode = BPF_OP(insn->code);
+ u8 mode = BPF_MODE(insn->code);
+ u32 dreg = 1u << insn->dst_reg;
+ u32 sreg = 1u << insn->src_reg;
+ u32 spi;
+
+ if (insn->code == 0)
+ return 0;
+ if (env->log.level & BPF_LOG_LEVEL) {
+ verbose(env, "regs=%x stack=%llx before ", *reg_mask, *stack_mask);
+ verbose(env, "%d: ", idx);
+ print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
+ }
+
+ if (class == BPF_ALU || class == BPF_ALU64) {
+ if (!(*reg_mask & dreg))
+ return 0;
+ if (opcode == BPF_MOV) {
+ if (BPF_SRC(insn->code) == BPF_X) {
+ /* dreg = sreg
+ * dreg needs precision after this insn
+ * sreg needs precision before this insn
+ */
+ *reg_mask &= ~dreg;
+ *reg_mask |= sreg;
+ } else {
+ /* dreg = K
+ * dreg needs precision after this insn.
+ * Corresponding register is already marked
+ * as precise=true in this verifier state.
+ * No further markings in parent are necessary
+ */
+ *reg_mask &= ~dreg;
+ }
+ } else {
+ if (BPF_SRC(insn->code) == BPF_X) {
+ /* dreg += sreg
+ * both dreg and sreg need precision
+ * before this insn
+ */
+ *reg_mask |= sreg;
+ } /* else dreg += K
+ * dreg still needs precision before this insn
+ */
+ }
+ } else if (class == BPF_LDX) {
+ if (!(*reg_mask & dreg))
+ return 0;
+ *reg_mask &= ~dreg;
+
+ /* scalars can only be spilled into stack w/o losing precision.
+ * Load from any other memory can be zero extended.
+ * The desire to keep that precision is already indicated
+ * by 'precise' mark in corresponding register of this state.
+ * No further tracking necessary.
+ */
+ if (insn->src_reg != BPF_REG_FP)
+ return 0;
+ if (BPF_SIZE(insn->code) != BPF_DW)
+ return 0;
+
+ /* dreg = *(u64 *)[fp - off] was a fill from the stack.
+ * that [fp - off] slot contains scalar that needs to be
+ * tracked with precision
+ */
+ spi = (-insn->off - 1) / BPF_REG_SIZE;
+ if (spi >= 64) {
+ verbose(env, "BUG spi %d\n", spi);
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ *stack_mask |= 1ull << spi;
+ } else if (class == BPF_STX || class == BPF_ST) {
+ if (*reg_mask & dreg)
+ /* stx & st shouldn't be using _scalar_ dst_reg
+ * to access memory. It means backtracking
+ * encountered a case of pointer subtraction.
+ */
+ return -ENOTSUPP;
+ /* scalars can only be spilled into stack */
+ if (insn->dst_reg != BPF_REG_FP)
+ return 0;
+ if (BPF_SIZE(insn->code) != BPF_DW)
+ return 0;
+ spi = (-insn->off - 1) / BPF_REG_SIZE;
+ if (spi >= 64) {
+ verbose(env, "BUG spi %d\n", spi);
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ if (!(*stack_mask & (1ull << spi)))
+ return 0;
+ *stack_mask &= ~(1ull << spi);
+ if (class == BPF_STX)
+ *reg_mask |= sreg;
+ } else if (class == BPF_JMP || class == BPF_JMP32) {
+ if (opcode == BPF_CALL) {
+ if (insn->src_reg == BPF_PSEUDO_CALL)
+ return -ENOTSUPP;
+ /* regular helper call sets R0 */
+ *reg_mask &= ~1;
+ if (*reg_mask & 0x3f) {
+ /* if backtracing was looking for registers R1-R5
+ * they should have been found already.
+ */
+ verbose(env, "BUG regs %x\n", *reg_mask);
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ } else if (opcode == BPF_EXIT) {
+ return -ENOTSUPP;
+ }
+ } else if (class == BPF_LD) {
+ if (!(*reg_mask & dreg))
+ return 0;
+ *reg_mask &= ~dreg;
+ /* It's ld_imm64 or ld_abs or ld_ind.
+ * For ld_imm64 no further tracking of precision
+ * into parent is necessary
+ */
+ if (mode == BPF_IND || mode == BPF_ABS)
+ /* to be analyzed */
+ return -ENOTSUPP;
+ }
+ return 0;
+}
+
+/* the scalar precision tracking algorithm:
+ * . at the start all registers have precise=false.
+ * . scalar ranges are tracked as normal through alu and jmp insns.
+ * . once precise value of the scalar register is used in:
+ * . ptr + scalar alu
+ * . if (scalar cond K|scalar)
+ * . helper_call(.., scalar, ...) where ARG_CONST is expected
+ * backtrack through the verifier states and mark all registers and
+ * stack slots with spilled constants that these scalar regisers
+ * should be precise.
+ * . during state pruning two registers (or spilled stack slots)
+ * are equivalent if both are not precise.
+ *
+ * Note the verifier cannot simply walk register parentage chain,
+ * since many different registers and stack slots could have been
+ * used to compute single precise scalar.
+ *
+ * The approach of starting with precise=true for all registers and then
+ * backtrack to mark a register as not precise when the verifier detects
+ * that program doesn't care about specific value (e.g., when helper
+ * takes register as ARG_ANYTHING parameter) is not safe.
+ *
+ * It's ok to walk single parentage chain of the verifier states.
+ * It's possible that this backtracking will go all the way till 1st insn.
+ * All other branches will be explored for needing precision later.
+ *
+ * The backtracking needs to deal with cases like:
+ * R8=map_value(id=0,off=0,ks=4,vs=1952,imm=0) R9_w=map_value(id=0,off=40,ks=4,vs=1952,imm=0)
+ * r9 -= r8
+ * r5 = r9
+ * if r5 > 0x79f goto pc+7
+ * R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff))
+ * r5 += 1
+ * ...
+ * call bpf_perf_event_output#25
+ * where .arg5_type = ARG_CONST_SIZE_OR_ZERO
+ *
+ * and this case:
+ * r6 = 1
+ * call foo // uses callee's r6 inside to compute r0
+ * r0 += r6
+ * if r0 == 0 goto
+ *
+ * to track above reg_mask/stack_mask needs to be independent for each frame.
+ *
+ * Also if parent's curframe > frame where backtracking started,
+ * the verifier need to mark registers in both frames, otherwise callees
+ * may incorrectly prune callers. This is similar to
+ * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences")
+ *
+ * For now backtracking falls back into conservative marking.
+ */
+static void mark_all_scalars_precise(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *st)
+{
+ struct bpf_func_state *func;
+ struct bpf_reg_state *reg;
+ int i, j;
+
+ /* big hammer: mark all scalars precise in this path.
+ * pop_stack may still get !precise scalars.
+ */
+ for (; st; st = st->parent)
+ for (i = 0; i <= st->curframe; i++) {
+ func = st->frame[i];
+ for (j = 0; j < BPF_REG_FP; j++) {
+ reg = &func->regs[j];
+ if (reg->type != SCALAR_VALUE)
+ continue;
+ reg->precise = true;
+ }
+ for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
+ if (func->stack[j].slot_type[0] != STACK_SPILL)
+ continue;
+ reg = &func->stack[j].spilled_ptr;
+ if (reg->type != SCALAR_VALUE)
+ continue;
+ reg->precise = true;
+ }
+ }
+}
+
+static int __mark_chain_precision(struct bpf_verifier_env *env, int regno,
+ int spi)
+{
+ struct bpf_verifier_state *st = env->cur_state;
+ int first_idx = st->first_insn_idx;
+ int last_idx = env->insn_idx;
+ struct bpf_func_state *func;
+ struct bpf_reg_state *reg;
+ u32 reg_mask = regno >= 0 ? 1u << regno : 0;
+ u64 stack_mask = spi >= 0 ? 1ull << spi : 0;
+ bool skip_first = true;
+ bool new_marks = false;
+ int i, err;
+
+ if (!env->allow_ptr_leaks)
+ /* backtracking is root only for now */
+ return 0;
+
+ func = st->frame[st->curframe];
+ if (regno >= 0) {
+ reg = &func->regs[regno];
+ if (reg->type != SCALAR_VALUE) {
+ WARN_ONCE(1, "backtracing misuse");
+ return -EFAULT;
+ }
+ if (!reg->precise)
+ new_marks = true;
+ else
+ reg_mask = 0;
+ reg->precise = true;
+ }
+
+ while (spi >= 0) {
+ if (func->stack[spi].slot_type[0] != STACK_SPILL) {
+ stack_mask = 0;
+ break;
+ }
+ reg = &func->stack[spi].spilled_ptr;
+ if (reg->type != SCALAR_VALUE) {
+ stack_mask = 0;
+ break;
+ }
+ if (!reg->precise)
+ new_marks = true;
+ else
+ stack_mask = 0;
+ reg->precise = true;
+ break;
+ }
+
+ if (!new_marks)
+ return 0;
+ if (!reg_mask && !stack_mask)
+ return 0;
+ for (;;) {
+ DECLARE_BITMAP(mask, 64);
+ u32 history = st->jmp_history_cnt;
+
+ if (env->log.level & BPF_LOG_LEVEL)
+ verbose(env, "last_idx %d first_idx %d\n", last_idx, first_idx);
+ for (i = last_idx;;) {
+ if (skip_first) {
+ err = 0;
+ skip_first = false;
+ } else {
+ err = backtrack_insn(env, i, ®_mask, &stack_mask);
+ }
+ if (err == -ENOTSUPP) {
+ mark_all_scalars_precise(env, st);
+ return 0;
+ } else if (err) {
+ return err;
+ }
+ if (!reg_mask && !stack_mask)
+ /* Found assignment(s) into tracked register in this state.
+ * Since this state is already marked, just return.
+ * Nothing to be tracked further in the parent state.
+ */
+ return 0;
+ if (i == first_idx)
+ break;
+ i = get_prev_insn_idx(st, i, &history);
+ if (i >= env->prog->len) {
+ /* This can happen if backtracking reached insn 0
+ * and there are still reg_mask or stack_mask
+ * to backtrack.
+ * It means the backtracking missed the spot where
+ * particular register was initialized with a constant.
+ */
+ verbose(env, "BUG backtracking idx %d\n", i);
+ WARN_ONCE(1, "verifier backtracking bug");
+ return -EFAULT;
+ }
+ }
+ st = st->parent;
+ if (!st)
+ break;
+
+ new_marks = false;
+ func = st->frame[st->curframe];
+ bitmap_from_u64(mask, reg_mask);
+ for_each_set_bit(i, mask, 32) {
+ reg = &func->regs[i];
+ if (reg->type != SCALAR_VALUE) {
+ reg_mask &= ~(1u << i);
+ continue;
+ }
+ if (!reg->precise)
+ new_marks = true;
+ reg->precise = true;
+ }
+
+ bitmap_from_u64(mask, stack_mask);
+ for_each_set_bit(i, mask, 64) {
+ if (i >= func->allocated_stack / BPF_REG_SIZE) {
+ /* the sequence of instructions:
+ * 2: (bf) r3 = r10
+ * 3: (7b) *(u64 *)(r3 -8) = r0
+ * 4: (79) r4 = *(u64 *)(r10 -8)
+ * doesn't contain jmps. It's backtracked
+ * as a single block.
+ * During backtracking insn 3 is not recognized as
+ * stack access, so at the end of backtracking
+ * stack slot fp-8 is still marked in stack_mask.
+ * However the parent state may not have accessed
+ * fp-8 and it's "unallocated" stack space.
+ * In such case fallback to conservative.
+ */
+ mark_all_scalars_precise(env, st);
+ return 0;
+ }
+
+ if (func->stack[i].slot_type[0] != STACK_SPILL) {
+ stack_mask &= ~(1ull << i);
+ continue;
+ }
+ reg = &func->stack[i].spilled_ptr;
+ if (reg->type != SCALAR_VALUE) {
+ stack_mask &= ~(1ull << i);
+ continue;
+ }
+ if (!reg->precise)
+ new_marks = true;
+ reg->precise = true;
+ }
+ if (env->log.level & BPF_LOG_LEVEL) {
+ print_verifier_state(env, func);
+ verbose(env, "parent %s regs=%x stack=%llx marks\n",
+ new_marks ? "didn't have" : "already had",
+ reg_mask, stack_mask);
+ }
+
+ if (!reg_mask && !stack_mask)
+ break;
+ if (!new_marks)
+ break;
+
+ last_idx = st->last_insn_idx;
+ first_idx = st->first_insn_idx;
+ }
+ return 0;
+}
+
+static int mark_chain_precision(struct bpf_verifier_env *env, int regno)
+{
+ return __mark_chain_precision(env, regno, -1);
+}
+
+static int mark_chain_precision_stack(struct bpf_verifier_env *env, int spi)
+{
+ return __mark_chain_precision(env, -1, spi);
+}
+
static bool is_spillable_regtype(enum bpf_reg_type type)
{
switch (type) {
@@ -997,7 +1840,15 @@
case PTR_TO_PACKET:
case PTR_TO_PACKET_META:
case PTR_TO_PACKET_END:
+ case PTR_TO_FLOW_KEYS:
case CONST_PTR_TO_MAP:
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCKET_OR_NULL:
+ case PTR_TO_SOCK_COMMON:
+ case PTR_TO_SOCK_COMMON_OR_NULL:
+ case PTR_TO_TCP_SOCK:
+ case PTR_TO_TCP_SOCK_OR_NULL:
+ case PTR_TO_XDP_SOCK:
return true;
default:
return false;
@@ -1010,6 +1861,23 @@
return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0);
}
+static bool register_is_const(struct bpf_reg_state *reg)
+{
+ return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off);
+}
+
+static void save_register_state(struct bpf_func_state *state,
+ int spi, struct bpf_reg_state *reg)
+{
+ int i;
+
+ state->stack[spi].spilled_ptr = *reg;
+ state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+ for (i = 0; i < BPF_REG_SIZE; i++)
+ state->stack[spi].slot_type[i] = STACK_SPILL;
+}
+
/* check_stack_read/write functions track spill/fill of registers,
* stack boundary and alignment are checked in check_mem_access()
*/
@@ -1019,10 +1887,11 @@
{
struct bpf_func_state *cur; /* state of the current function */
int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
- enum bpf_reg_type type;
+ u32 dst_reg = env->prog->insnsi[insn_idx].dst_reg;
+ struct bpf_reg_state *reg = NULL;
err = realloc_func_state(state, round_up(slot + 1, BPF_REG_SIZE),
- true);
+ state->acquired_refs, true);
if (err)
return err;
/* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
@@ -1036,27 +1905,48 @@
}
cur = env->cur_state->frame[env->cur_state->curframe];
- if (value_regno >= 0 &&
- is_spillable_regtype((type = cur->regs[value_regno].type))) {
+ if (value_regno >= 0)
+ reg = &cur->regs[value_regno];
+ if (reg && size == BPF_REG_SIZE && register_is_const(reg) &&
+ !register_is_null(reg) && env->allow_ptr_leaks) {
+ if (dst_reg != BPF_REG_FP) {
+ /* The backtracking logic can only recognize explicit
+ * stack slot address like [fp - 8]. Other spill of
+ * scalar via different register has to be conervative.
+ * Backtrack from here and mark all registers as precise
+ * that contributed into 'reg' being a constant.
+ */
+ err = mark_chain_precision(env, value_regno);
+ if (err)
+ return err;
+ }
+ save_register_state(state, spi, reg);
+ } else if (reg && is_spillable_regtype(reg->type)) {
/* register containing pointer is being spilled into stack */
if (size != BPF_REG_SIZE) {
+ verbose_linfo(env, insn_idx, "; ");
verbose(env, "invalid size of register spill\n");
return -EACCES;
}
- if (state != cur && type == PTR_TO_STACK) {
+ if (state != cur && reg->type == PTR_TO_STACK) {
verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
return -EINVAL;
}
- /* save register state */
- state->stack[spi].spilled_ptr = cur->regs[value_regno];
- state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+ if (!env->allow_ptr_leaks) {
+ bool sanitize = false;
- for (i = 0; i < BPF_REG_SIZE; i++) {
- if (state->stack[spi].slot_type[i] == STACK_MISC &&
- !env->allow_ptr_leaks) {
+ if (state->stack[spi].slot_type[0] == STACK_SPILL &&
+ register_is_const(&state->stack[spi].spilled_ptr))
+ sanitize = true;
+ for (i = 0; i < BPF_REG_SIZE; i++)
+ if (state->stack[spi].slot_type[i] == STACK_MISC) {
+ sanitize = true;
+ break;
+ }
+ if (sanitize) {
int *poff = &env->insn_aux_data[insn_idx].sanitize_stack_off;
int soff = (-spi - 1) * BPF_REG_SIZE;
@@ -1079,13 +1969,17 @@
}
*poff = soff;
}
- state->stack[spi].slot_type[i] = STACK_SPILL;
}
+ save_register_state(state, spi, reg);
} else {
u8 type = STACK_MISC;
- /* regular write of data into stack */
- state->stack[spi].spilled_ptr = (struct bpf_reg_state) {};
+ /* regular write of data into stack destroys any spilled ptr */
+ state->stack[spi].spilled_ptr.type = NOT_INIT;
+ /* Mark slots as STACK_MISC if they belonged to spilled ptr. */
+ if (state->stack[spi].slot_type[0] == STACK_SPILL)
+ for (i = 0; i < BPF_REG_SIZE; i++)
+ state->stack[spi].slot_type[i] = STACK_MISC;
/* only mark the slot as written if all 8 bytes were written
* otherwise read propagation may incorrectly stop too soon
@@ -1099,10 +1993,15 @@
state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
/* when we zero initialize stack slots mark them as such */
- if (value_regno >= 0 &&
- register_is_null(&cur->regs[value_regno]))
+ if (reg && register_is_null(reg)) {
+ /* backtracking doesn't work for STACK_ZERO yet. */
+ err = mark_chain_precision(env, value_regno);
+ if (err)
+ return err;
type = STACK_ZERO;
+ }
+ /* Mark slots affected by this stack write. */
for (i = 0; i < size; i++)
state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] =
type;
@@ -1110,61 +2009,6 @@
return 0;
}
-/* registers of every function are unique and mark_reg_read() propagates
- * the liveness in the following cases:
- * - from callee into caller for R1 - R5 that were used as arguments
- * - from caller into callee for R0 that used as result of the call
- * - from caller to the same caller skipping states of the callee for R6 - R9,
- * since R6 - R9 are callee saved by implicit function prologue and
- * caller's R6 != callee's R6, so when we propagate liveness up to
- * parent states we need to skip callee states for R6 - R9.
- *
- * stack slot marking is different, since stacks of caller and callee are
- * accessible in both (since caller can pass a pointer to caller's stack to
- * callee which can pass it to another function), hence mark_stack_slot_read()
- * has to propagate the stack liveness to all parent states at given frame number.
- * Consider code:
- * f1() {
- * ptr = fp - 8;
- * *ptr = ctx;
- * call f2 {
- * .. = *ptr;
- * }
- * .. = *ptr;
- * }
- * First *ptr is reading from f1's stack and mark_stack_slot_read() has
- * to mark liveness at the f1's frame and not f2's frame.
- * Second *ptr is also reading from f1's stack and mark_stack_slot_read() has
- * to propagate liveness to f2 states at f1's frame level and further into
- * f1 states at f1's frame level until write into that stack slot
- */
-static void mark_stack_slot_read(struct bpf_verifier_env *env,
- const struct bpf_verifier_state *state,
- struct bpf_verifier_state *parent,
- int slot, int frameno)
-{
- bool writes = parent == state->parent; /* Observe write marks */
-
- while (parent) {
- if (parent->frame[frameno]->allocated_stack <= slot * BPF_REG_SIZE)
- /* since LIVE_WRITTEN mark is only done for full 8-byte
- * write the read marks are conservative and parent
- * state may not even have the stack allocated. In such case
- * end the propagation, since the loop reached beginning
- * of the function
- */
- break;
- /* if read wasn't screened by an earlier write ... */
- if (writes && state->frame[frameno]->stack[slot].spilled_ptr.live & REG_LIVE_WRITTEN)
- break;
- /* ... then we depend on parent's value */
- parent->frame[frameno]->stack[slot].spilled_ptr.live |= REG_LIVE_READ;
- state = parent;
- parent = state->parent;
- writes = true;
- }
-}
-
static int check_stack_read(struct bpf_verifier_env *env,
struct bpf_func_state *reg_state /* func where register points to */,
int off, int size, int value_regno)
@@ -1172,6 +2016,7 @@
struct bpf_verifier_state *vstate = env->cur_state;
struct bpf_func_state *state = vstate->frame[vstate->curframe];
int i, slot = -off - 1, spi = slot / BPF_REG_SIZE;
+ struct bpf_reg_state *reg;
u8 *stype;
if (reg_state->allocated_stack <= slot) {
@@ -1180,11 +2025,21 @@
return -EACCES;
}
stype = reg_state->stack[spi].slot_type;
+ reg = ®_state->stack[spi].spilled_ptr;
if (stype[0] == STACK_SPILL) {
if (size != BPF_REG_SIZE) {
- verbose(env, "invalid size of register spill\n");
- return -EACCES;
+ if (reg->type != SCALAR_VALUE) {
+ verbose_linfo(env, env->insn_idx, "; ");
+ verbose(env, "invalid size of register fill\n");
+ return -EACCES;
+ }
+ if (value_regno >= 0) {
+ mark_reg_unknown(env, state->regs, value_regno);
+ state->regs[value_regno].live |= REG_LIVE_WRITTEN;
+ }
+ mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+ return 0;
}
for (i = 1; i < BPF_REG_SIZE; i++) {
if (stype[(slot - i) % BPF_REG_SIZE] != STACK_SPILL) {
@@ -1195,16 +2050,14 @@
if (value_regno >= 0) {
/* restore register state from stack */
- state->regs[value_regno] = reg_state->stack[spi].spilled_ptr;
+ state->regs[value_regno] = *reg;
/* mark reg as written since spilled pointer state likely
* has its liveness marks cleared by is_state_visited()
* which resets stack/reg liveness for state transitions
*/
state->regs[value_regno].live |= REG_LIVE_WRITTEN;
}
- mark_stack_slot_read(env, vstate, vstate->parent, spi,
- reg_state->frameno);
- return 0;
+ mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
} else {
int zeros = 0;
@@ -1219,22 +2072,79 @@
off, i, size);
return -EACCES;
}
- mark_stack_slot_read(env, vstate, vstate->parent, spi,
- reg_state->frameno);
+ mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
if (value_regno >= 0) {
if (zeros == size) {
/* any size read into register is zero extended,
* so the whole register == const_zero
*/
__mark_reg_const_zero(&state->regs[value_regno]);
+ /* backtracking doesn't support STACK_ZERO yet,
+ * so mark it precise here, so that later
+ * backtracking can stop here.
+ * Backtracking may not need this if this register
+ * doesn't participate in pointer adjustment.
+ * Forward propagation of precise flag is not
+ * necessary either. This mark is only to stop
+ * backtracking. Any register that contributed
+ * to const 0 was marked precise before spill.
+ */
+ state->regs[value_regno].precise = true;
} else {
/* have read misc data from the stack */
mark_reg_unknown(env, state->regs, value_regno);
}
state->regs[value_regno].live |= REG_LIVE_WRITTEN;
}
- return 0;
}
+ return 0;
+}
+
+static int check_stack_access(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ int off, int size)
+{
+ /* Stack accesses must be at a fixed offset, so that we
+ * can determine what type of data were returned. See
+ * check_stack_read().
+ */
+ if (!tnum_is_const(reg->var_off)) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "variable stack access var_off=%s off=%d size=%d\n",
+ tn_buf, off, size);
+ return -EACCES;
+ }
+
+ if (off >= 0 || off < -MAX_BPF_STACK) {
+ verbose(env, "invalid stack off=%d size=%d\n", off, size);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int check_map_access_type(struct bpf_verifier_env *env, u32 regno,
+ int off, int size, enum bpf_access_type type)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_map *map = regs[regno].map_ptr;
+ u32 cap = bpf_map_flags_to_cap(map);
+
+ if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) {
+ verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n",
+ map->value_size, off, size);
+ return -EACCES;
+ }
+
+ if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) {
+ verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n",
+ map->value_size, off, size);
+ return -EACCES;
+ }
+
+ return 0;
}
/* check read/write into map element returned by bpf_map_lookup_elem() */
@@ -1266,15 +2176,19 @@
* need to try adding each of min_value and max_value to off
* to make sure our theoretical access will be safe.
*/
- if (env->log.level)
+ if (env->log.level & BPF_LOG_LEVEL)
print_verifier_state(env, state);
+
/* The minimum value is only important with signed
* comparisons where we can't assume the floor of a
* value is 0. If we are using signed variables for our
* index'es we need to make sure that whatever we use
* will have a set floor within our range.
*/
- if (reg->smin_value < 0) {
+ if (reg->smin_value < 0 &&
+ (reg->smin_value == S64_MIN ||
+ (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) ||
+ reg->smin_value + off < 0)) {
verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
regno);
return -EACCES;
@@ -1301,6 +2215,21 @@
if (err)
verbose(env, "R%d max value is outside of the array range\n",
regno);
+
+ if (map_value_has_spin_lock(reg->map_ptr)) {
+ u32 lock = reg->map_ptr->spin_lock_off;
+
+ /* if any part of struct bpf_spin_lock can be touched by
+ * load/store reject this program.
+ * To check that [x1, x2) overlaps with [y1, y2)
+ * it is sufficient to check x1 < y2 && y1 < x2.
+ */
+ if (reg->smin_value + off < lock + sizeof(struct bpf_spin_lock) &&
+ lock < reg->umax_value + off + size) {
+ verbose(env, "bpf_spin_lock cannot be accessed directly by load/store\n");
+ return -EACCES;
+ }
+ }
return err;
}
@@ -1311,14 +2240,18 @@
enum bpf_access_type t)
{
switch (env->prog->type) {
+ /* Program types only with direct read access go here! */
case BPF_PROG_TYPE_LWT_IN:
case BPF_PROG_TYPE_LWT_OUT:
case BPF_PROG_TYPE_LWT_SEG6LOCAL:
case BPF_PROG_TYPE_SK_REUSEPORT:
- /* dst_input() and dst_output() can't write for now */
+ case BPF_PROG_TYPE_FLOW_DISSECTOR:
+ case BPF_PROG_TYPE_CGROUP_SKB:
if (t == BPF_WRITE)
return false;
/* fallthrough */
+
+ /* Program types with direct read + write access go here! */
case BPF_PROG_TYPE_SCHED_CLS:
case BPF_PROG_TYPE_SCHED_ACT:
case BPF_PROG_TYPE_XDP:
@@ -1330,6 +2263,13 @@
env->seen_direct_write = true;
return true;
+
+ case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+ if (t == BPF_WRITE)
+ env->seen_direct_write = true;
+
+ return true;
+
default:
return false;
}
@@ -1375,6 +2315,17 @@
verbose(env, "R%d offset is outside of the packet\n", regno);
return err;
}
+
+ /* __check_packet_access has made sure "off + size - 1" is within u16.
+ * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
+ * otherwise find_good_pkt_pointers would have refused to set range info
+ * that __check_packet_access would have rejected this pkt access.
+ * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
+ */
+ env->prog->aux->max_pkt_offset =
+ max_t(u32, env->prog->aux->max_pkt_offset,
+ off + reg->umax_value + size - 1);
+
return err;
}
@@ -1408,6 +2359,63 @@
return -EACCES;
}
+static int check_flow_keys_access(struct bpf_verifier_env *env, int off,
+ int size)
+{
+ if (size < 0 || off < 0 ||
+ (u64)off + size > sizeof(struct bpf_flow_keys)) {
+ verbose(env, "invalid access to flow keys off=%d size=%d\n",
+ off, size);
+ return -EACCES;
+ }
+ return 0;
+}
+
+static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
+ u32 regno, int off, int size,
+ enum bpf_access_type t)
+{
+ struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_reg_state *reg = ®s[regno];
+ struct bpf_insn_access_aux info = {};
+ bool valid;
+
+ if (reg->smin_value < 0) {
+ verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+ regno);
+ return -EACCES;
+ }
+
+ switch (reg->type) {
+ case PTR_TO_SOCK_COMMON:
+ valid = bpf_sock_common_is_valid_access(off, size, t, &info);
+ break;
+ case PTR_TO_SOCKET:
+ valid = bpf_sock_is_valid_access(off, size, t, &info);
+ break;
+ case PTR_TO_TCP_SOCK:
+ valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
+ break;
+ case PTR_TO_XDP_SOCK:
+ valid = bpf_xdp_sock_is_valid_access(off, size, t, &info);
+ break;
+ default:
+ valid = false;
+ }
+
+
+ if (valid) {
+ env->insn_aux_data[insn_idx].ctx_field_size =
+ info.ctx_field_size;
+ return 0;
+ }
+
+ verbose(env, "R%d invalid %s access off=%d size=%d\n",
+ regno, reg_type_str[reg->type], off, size);
+
+ return -EACCES;
+}
+
static bool __is_pointer_value(bool allow_ptr_leaks,
const struct bpf_reg_state *reg)
{
@@ -1417,25 +2425,45 @@
return reg->type != SCALAR_VALUE;
}
+static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)
+{
+ return cur_regs(env) + regno;
+}
+
static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
{
- return __is_pointer_value(env->allow_ptr_leaks, cur_regs(env) + regno);
+ return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno));
}
static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
{
- const struct bpf_reg_state *reg = cur_regs(env) + regno;
+ const struct bpf_reg_state *reg = reg_state(env, regno);
return reg->type == PTR_TO_CTX;
}
+static bool is_sk_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = reg_state(env, regno);
+
+ return type_is_sk_pointer(reg->type);
+}
+
static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
{
- const struct bpf_reg_state *reg = cur_regs(env) + regno;
+ const struct bpf_reg_state *reg = reg_state(env, regno);
return type_is_pkt_pointer(reg->type);
}
+static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
+{
+ const struct bpf_reg_state *reg = reg_state(env, regno);
+
+ /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
+ return reg->type == PTR_TO_FLOW_KEYS;
+}
+
static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
const struct bpf_reg_state *reg,
int off, int size, bool strict)
@@ -1509,6 +2537,9 @@
* right in front, treat it the very same way.
*/
return check_pkt_ptr_alignment(env, reg, off, size, strict);
+ case PTR_TO_FLOW_KEYS:
+ pointer_desc = "flow keys ";
+ break;
case PTR_TO_MAP_VALUE:
pointer_desc = "value ";
break;
@@ -1523,6 +2554,18 @@
*/
strict = true;
break;
+ case PTR_TO_SOCKET:
+ pointer_desc = "sock ";
+ break;
+ case PTR_TO_SOCK_COMMON:
+ pointer_desc = "sock_common ";
+ break;
+ case PTR_TO_TCP_SOCK:
+ pointer_desc = "tcp_sock ";
+ break;
+ case PTR_TO_XDP_SOCK:
+ pointer_desc = "xdp_sock ";
+ break;
default:
break;
}
@@ -1589,8 +2632,9 @@
}
frame++;
if (frame >= MAX_CALL_FRAMES) {
- WARN_ONCE(1, "verifier bug. Call stack is too deep\n");
- return -EFAULT;
+ verbose(env, "the call stack of %d frames is too deep !\n",
+ frame);
+ return -E2BIG;
}
goto process_func;
}
@@ -1646,6 +2690,32 @@
return 0;
}
+static int check_tp_buffer_access(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg,
+ int regno, int off, int size)
+{
+ if (off < 0) {
+ verbose(env,
+ "R%d invalid tracepoint buffer access: off=%d, size=%d",
+ regno, off, size);
+ return -EACCES;
+ }
+ if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env,
+ "R%d invalid variable buffer offset: off=%d, var_off=%s",
+ regno, off, tn_buf);
+ return -EACCES;
+ }
+ if (off + size > env->prog->aux->max_tp_access)
+ env->prog->aux->max_tp_access = off + size;
+
+ return 0;
+}
+
+
/* truncate register to smaller size (in bytes)
* must be called with size < BPF_REG_SIZE
*/
@@ -1702,7 +2772,9 @@
verbose(env, "R%d leaks addr into map\n", value_regno);
return -EACCES;
}
-
+ err = check_map_access_type(env, regno, off, size, t);
+ if (err)
+ return err;
err = check_map_access(env, regno, off, size, false);
if (!err && t == BPF_READ && value_regno >= 0)
mark_reg_unknown(env, regs, value_regno);
@@ -1726,33 +2798,28 @@
* PTR_TO_PACKET[_META,_END]. In the latter
* case, we know the offset is zero.
*/
- if (reg_type == SCALAR_VALUE)
+ if (reg_type == SCALAR_VALUE) {
mark_reg_unknown(env, regs, value_regno);
- else
+ } else {
mark_reg_known_zero(env, regs,
value_regno);
+ if (reg_type_may_be_null(reg_type))
+ regs[value_regno].id = ++env->id_gen;
+ /* A load of ctx field could have different
+ * actual load size with the one encoded in the
+ * insn. When the dst is PTR, it is for sure not
+ * a sub-register.
+ */
+ regs[value_regno].subreg_def = DEF_NOT_SUBREG;
+ }
regs[value_regno].type = reg_type;
}
} else if (reg->type == PTR_TO_STACK) {
- /* stack accesses must be at a fixed offset, so that we can
- * determine what type of data were returned.
- * See check_stack_read().
- */
- if (!tnum_is_const(reg->var_off)) {
- char tn_buf[48];
-
- tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
- verbose(env, "variable stack access var_off=%s off=%d size=%d",
- tn_buf, off, size);
- return -EACCES;
- }
off += reg->var_off.value;
- if (off >= 0 || off < -MAX_BPF_STACK) {
- verbose(env, "invalid stack off=%d size=%d\n", off,
- size);
- return -EACCES;
- }
+ err = check_stack_access(env, reg, off, size);
+ if (err)
+ return err;
state = func(env, reg);
err = update_stack_depth(env, state, off);
@@ -1779,6 +2846,30 @@
err = check_packet_access(env, regno, off, size, false);
if (!err && t == BPF_READ && value_regno >= 0)
mark_reg_unknown(env, regs, value_regno);
+ } else if (reg->type == PTR_TO_FLOW_KEYS) {
+ if (t == BPF_WRITE && value_regno >= 0 &&
+ is_pointer_value(env, value_regno)) {
+ verbose(env, "R%d leaks addr into flow keys\n",
+ value_regno);
+ return -EACCES;
+ }
+
+ err = check_flow_keys_access(env, off, size);
+ if (!err && t == BPF_READ && value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
+ } else if (type_is_sk_pointer(reg->type)) {
+ if (t == BPF_WRITE) {
+ verbose(env, "R%d cannot write into %s\n",
+ regno, reg_type_str[reg->type]);
+ return -EACCES;
+ }
+ err = check_sock_access(env, insn_idx, regno, off, size, t);
+ if (!err && value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
+ } else if (reg->type == PTR_TO_TP_BUFFER) {
+ err = check_tp_buffer_access(env, reg, regno, off, size);
+ if (!err && t == BPF_READ && value_regno >= 0)
+ mark_reg_unknown(env, regs, value_regno);
} else {
verbose(env, "R%d invalid mem access '%s'\n", regno,
reg_type_str[reg->type]);
@@ -1819,10 +2910,12 @@
}
if (is_ctx_reg(env, insn->dst_reg) ||
- is_pkt_reg(env, insn->dst_reg)) {
+ is_pkt_reg(env, insn->dst_reg) ||
+ is_flow_key_reg(env, insn->dst_reg) ||
+ is_sk_reg(env, insn->dst_reg)) {
verbose(env, "BPF_XADD stores into R%d %s is not allowed\n",
- insn->dst_reg, is_ctx_reg(env, insn->dst_reg) ?
- "context" : "packet");
+ insn->dst_reg,
+ reg_type_str[reg_state(env, insn->dst_reg)->type]);
return -EACCES;
}
@@ -1837,6 +2930,29 @@
BPF_SIZE(insn->code), BPF_WRITE, -1, true);
}
+static int __check_stack_boundary(struct bpf_verifier_env *env, u32 regno,
+ int off, int access_size,
+ bool zero_size_allowed)
+{
+ struct bpf_reg_state *reg = reg_state(env, regno);
+
+ if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
+ access_size < 0 || (access_size == 0 && !zero_size_allowed)) {
+ if (tnum_is_const(reg->var_off)) {
+ verbose(env, "invalid stack type R%d off=%d access_size=%d\n",
+ regno, off, access_size);
+ } else {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "invalid stack type R%d var_off=%s access_size=%d\n",
+ regno, tn_buf, access_size);
+ }
+ return -EACCES;
+ }
+ return 0;
+}
+
/* when register 'regno' is passed into function that will read 'access_size'
* bytes from that pointer, make sure that it's within stack boundary
* and all elements of stack are initialized.
@@ -1847,9 +2963,9 @@
int access_size, bool zero_size_allowed,
struct bpf_call_arg_meta *meta)
{
- struct bpf_reg_state *reg = cur_regs(env) + regno;
+ struct bpf_reg_state *reg = reg_state(env, regno);
struct bpf_func_state *state = func(env, reg);
- int off, i, slot, spi;
+ int err, min_off, max_off, i, j, slot, spi;
if (reg->type != PTR_TO_STACK) {
/* Allow zero-byte read from NULL, regardless of pointer type */
@@ -1863,21 +2979,57 @@
return -EACCES;
}
- /* Only allow fixed-offset stack reads */
- if (!tnum_is_const(reg->var_off)) {
- char tn_buf[48];
+ if (tnum_is_const(reg->var_off)) {
+ min_off = max_off = reg->var_off.value + reg->off;
+ err = __check_stack_boundary(env, regno, min_off, access_size,
+ zero_size_allowed);
+ if (err)
+ return err;
+ } else {
+ /* Variable offset is prohibited for unprivileged mode for
+ * simplicity since it requires corresponding support in
+ * Spectre masking for stack ALU.
+ * See also retrieve_ptr_limit().
+ */
+ if (!env->allow_ptr_leaks) {
+ char tn_buf[48];
- tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
- verbose(env, "invalid variable stack read R%d var_off=%s\n",
- regno, tn_buf);
- return -EACCES;
- }
- off = reg->off + reg->var_off.value;
- if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
- access_size < 0 || (access_size == 0 && !zero_size_allowed)) {
- verbose(env, "invalid stack type R%d off=%d access_size=%d\n",
- regno, off, access_size);
- return -EACCES;
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "R%d indirect variable offset stack access prohibited for !root, var_off=%s\n",
+ regno, tn_buf);
+ return -EACCES;
+ }
+ /* Only initialized buffer on stack is allowed to be accessed
+ * with variable offset. With uninitialized buffer it's hard to
+ * guarantee that whole memory is marked as initialized on
+ * helper return since specific bounds are unknown what may
+ * cause uninitialized stack leaking.
+ */
+ if (meta && meta->raw_mode)
+ meta = NULL;
+
+ if (reg->smax_value >= BPF_MAX_VAR_OFF ||
+ reg->smax_value <= -BPF_MAX_VAR_OFF) {
+ verbose(env, "R%d unbounded indirect variable offset stack access\n",
+ regno);
+ return -EACCES;
+ }
+ min_off = reg->smin_value + reg->off;
+ max_off = reg->smax_value + reg->off;
+ err = __check_stack_boundary(env, regno, min_off, access_size,
+ zero_size_allowed);
+ if (err) {
+ verbose(env, "R%d min value is outside of stack bound\n",
+ regno);
+ return err;
+ }
+ err = __check_stack_boundary(env, regno, max_off, access_size,
+ zero_size_allowed);
+ if (err) {
+ verbose(env, "R%d max value is outside of stack bound\n",
+ regno);
+ return err;
+ }
}
if (meta && meta->raw_mode) {
@@ -1886,10 +3038,10 @@
return 0;
}
- for (i = 0; i < access_size; i++) {
+ for (i = min_off; i < max_off + access_size; i++) {
u8 *stype;
- slot = -(off + i) - 1;
+ slot = -i - 1;
spi = slot / BPF_REG_SIZE;
if (state->allocated_stack <= slot)
goto err;
@@ -1901,18 +3053,35 @@
*stype = STACK_MISC;
goto mark;
}
+ if (state->stack[spi].slot_type[0] == STACK_SPILL &&
+ state->stack[spi].spilled_ptr.type == SCALAR_VALUE) {
+ __mark_reg_unknown(&state->stack[spi].spilled_ptr);
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ state->stack[spi].slot_type[j] = STACK_MISC;
+ goto mark;
+ }
+
err:
- verbose(env, "invalid indirect read from stack off %d+%d size %d\n",
- off, i, access_size);
+ if (tnum_is_const(reg->var_off)) {
+ verbose(env, "invalid indirect read from stack off %d+%d size %d\n",
+ min_off, i - min_off, access_size);
+ } else {
+ char tn_buf[48];
+
+ tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+ verbose(env, "invalid indirect read from stack var_off %s+%d size %d\n",
+ tn_buf, i - min_off, access_size);
+ }
return -EACCES;
mark:
/* reading any byte out of 8-byte 'spill_slot' will cause
* the whole slot to be marked as 'read'
*/
- mark_stack_slot_read(env, env->cur_state, env->cur_state->parent,
- spi, state->frameno);
+ mark_reg_read(env, &state->stack[spi].spilled_ptr,
+ state->stack[spi].spilled_ptr.parent,
+ REG_LIVE_READ64);
}
- return update_stack_depth(env, state, off);
+ return update_stack_depth(env, state, min_off);
}
static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
@@ -1927,6 +3096,10 @@
return check_packet_access(env, regno, reg->off, access_size,
zero_size_allowed);
case PTR_TO_MAP_VALUE:
+ if (check_map_access_type(env, regno, reg->off, access_size,
+ meta && meta->raw_mode ? BPF_WRITE :
+ BPF_READ))
+ return -EACCES;
return check_map_access(env, regno, reg->off, access_size,
zero_size_allowed);
default: /* scalar_value|ptr_to_stack or invalid ptr */
@@ -1935,6 +3108,91 @@
}
}
+/* Implementation details:
+ * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL
+ * Two bpf_map_lookups (even with the same key) will have different reg->id.
+ * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after
+ * value_or_null->value transition, since the verifier only cares about
+ * the range of access to valid map value pointer and doesn't care about actual
+ * address of the map element.
+ * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
+ * reg->id > 0 after value_or_null->value transition. By doing so
+ * two bpf_map_lookups will be considered two different pointers that
+ * point to different bpf_spin_locks.
+ * The verifier allows taking only one bpf_spin_lock at a time to avoid
+ * dead-locks.
+ * Since only one bpf_spin_lock is allowed the checks are simpler than
+ * reg_is_refcounted() logic. The verifier needs to remember only
+ * one spin_lock instead of array of acquired_refs.
+ * cur_state->active_spin_lock remembers which map value element got locked
+ * and clears it after bpf_spin_unlock.
+ */
+static int process_spin_lock(struct bpf_verifier_env *env, int regno,
+ bool is_lock)
+{
+ struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
+ struct bpf_verifier_state *cur = env->cur_state;
+ bool is_const = tnum_is_const(reg->var_off);
+ struct bpf_map *map = reg->map_ptr;
+ u64 val = reg->var_off.value;
+
+ if (reg->type != PTR_TO_MAP_VALUE) {
+ verbose(env, "R%d is not a pointer to map_value\n", regno);
+ return -EINVAL;
+ }
+ if (!is_const) {
+ verbose(env,
+ "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
+ regno);
+ return -EINVAL;
+ }
+ if (!map->btf) {
+ verbose(env,
+ "map '%s' has to have BTF in order to use bpf_spin_lock\n",
+ map->name);
+ return -EINVAL;
+ }
+ if (!map_value_has_spin_lock(map)) {
+ if (map->spin_lock_off == -E2BIG)
+ verbose(env,
+ "map '%s' has more than one 'struct bpf_spin_lock'\n",
+ map->name);
+ else if (map->spin_lock_off == -ENOENT)
+ verbose(env,
+ "map '%s' doesn't have 'struct bpf_spin_lock'\n",
+ map->name);
+ else
+ verbose(env,
+ "map '%s' is not a struct type or bpf_spin_lock is mangled\n",
+ map->name);
+ return -EINVAL;
+ }
+ if (map->spin_lock_off != val + reg->off) {
+ verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock'\n",
+ val + reg->off);
+ return -EINVAL;
+ }
+ if (is_lock) {
+ if (cur->active_spin_lock) {
+ verbose(env,
+ "Locking two bpf_spin_locks are not allowed\n");
+ return -EINVAL;
+ }
+ cur->active_spin_lock = reg->id;
+ } else {
+ if (!cur->active_spin_lock) {
+ verbose(env, "bpf_spin_unlock without taking a lock\n");
+ return -EINVAL;
+ }
+ if (cur->active_spin_lock != reg->id) {
+ verbose(env, "bpf_spin_unlock of different lock\n");
+ return -EINVAL;
+ }
+ cur->active_spin_lock = 0;
+ }
+ return 0;
+}
+
static bool arg_type_is_mem_ptr(enum bpf_arg_type type)
{
return type == ARG_PTR_TO_MEM ||
@@ -1948,6 +3206,22 @@
type == ARG_CONST_SIZE_OR_ZERO;
}
+static bool arg_type_is_int_ptr(enum bpf_arg_type type)
+{
+ return type == ARG_PTR_TO_INT ||
+ type == ARG_PTR_TO_LONG;
+}
+
+static int int_ptr_type_to_size(enum bpf_arg_type type)
+{
+ if (type == ARG_PTR_TO_INT)
+ return sizeof(u32);
+ else if (type == ARG_PTR_TO_LONG)
+ return sizeof(u64);
+
+ return -EINVAL;
+}
+
static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
enum bpf_arg_type arg_type,
struct bpf_call_arg_meta *meta)
@@ -1979,10 +3253,16 @@
}
if (arg_type == ARG_PTR_TO_MAP_KEY ||
- arg_type == ARG_PTR_TO_MAP_VALUE) {
+ arg_type == ARG_PTR_TO_MAP_VALUE ||
+ arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE ||
+ arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL) {
expected_type = PTR_TO_STACK;
- if (!type_is_pkt_pointer(type) && type != PTR_TO_MAP_VALUE &&
- type != expected_type)
+ if (register_is_null(reg) &&
+ arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL)
+ /* final test in check_stack_boundary() */;
+ else if (!type_is_pkt_pointer(type) &&
+ type != PTR_TO_MAP_VALUE &&
+ type != expected_type)
goto err_type;
} else if (arg_type == ARG_CONST_SIZE ||
arg_type == ARG_CONST_SIZE_OR_ZERO) {
@@ -2000,6 +3280,35 @@
err = check_ctx_reg(env, reg, regno);
if (err < 0)
return err;
+ } else if (arg_type == ARG_PTR_TO_SOCK_COMMON) {
+ expected_type = PTR_TO_SOCK_COMMON;
+ /* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */
+ if (!type_is_sk_pointer(type))
+ goto err_type;
+ if (reg->ref_obj_id) {
+ if (meta->ref_obj_id) {
+ verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+ regno, reg->ref_obj_id,
+ meta->ref_obj_id);
+ return -EFAULT;
+ }
+ meta->ref_obj_id = reg->ref_obj_id;
+ }
+ } else if (arg_type == ARG_PTR_TO_SOCKET) {
+ expected_type = PTR_TO_SOCKET;
+ if (type != expected_type)
+ goto err_type;
+ } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) {
+ if (meta->func_id == BPF_FUNC_spin_lock) {
+ if (process_spin_lock(env, regno, true))
+ return -EACCES;
+ } else if (meta->func_id == BPF_FUNC_spin_unlock) {
+ if (process_spin_lock(env, regno, false))
+ return -EACCES;
+ } else {
+ verbose(env, "verifier internal error\n");
+ return -EFAULT;
+ }
} else if (arg_type_is_mem_ptr(arg_type)) {
expected_type = PTR_TO_STACK;
/* One exception here. In case function allows for NULL to be
@@ -2014,6 +3323,12 @@
type != expected_type)
goto err_type;
meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM;
+ } else if (arg_type_is_int_ptr(arg_type)) {
+ expected_type = PTR_TO_STACK;
+ if (!type_is_pkt_pointer(type) &&
+ type != PTR_TO_MAP_VALUE &&
+ type != expected_type)
+ goto err_type;
} else {
verbose(env, "unsupported arg_type %d\n", arg_type);
return -EFAULT;
@@ -2039,7 +3354,10 @@
err = check_helper_mem_access(env, regno,
meta->map_ptr->key_size, false,
NULL);
- } else if (arg_type == ARG_PTR_TO_MAP_VALUE) {
+ } else if (arg_type == ARG_PTR_TO_MAP_VALUE ||
+ (arg_type == ARG_PTR_TO_MAP_VALUE_OR_NULL &&
+ !register_is_null(reg)) ||
+ arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE) {
/* bpf_map_xxx(..., map_ptr, ..., value) call:
* check [value, value + map->value_size) validity
*/
@@ -2048,9 +3366,10 @@
verbose(env, "invalid map_ptr to access map->value\n");
return -EACCES;
}
+ meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE);
err = check_helper_mem_access(env, regno,
meta->map_ptr->value_size, false,
- NULL);
+ meta);
} else if (arg_type_is_mem_size(arg_type)) {
bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO);
@@ -2093,6 +3412,15 @@
err = check_helper_mem_access(env, regno - 1,
reg->umax_value,
zero_size_allowed, meta);
+ if (!err)
+ err = mark_chain_precision(env, regno);
+ } else if (arg_type_is_int_ptr(arg_type)) {
+ int size = int_ptr_type_to_size(arg_type);
+
+ err = check_helper_mem_access(env, regno, size, false, meta);
+ if (err)
+ return err;
+ err = check_ptr_alignment(env, reg, 0, size, true);
}
return err;
@@ -2130,25 +3458,28 @@
goto error;
break;
case BPF_MAP_TYPE_CGROUP_STORAGE:
+ case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
if (func_id != BPF_FUNC_get_local_storage)
goto error;
break;
- /* devmap returns a pointer to a live net_device ifindex that we cannot
- * allow to be modified from bpf side. So do not allow lookup elements
- * for now.
- */
case BPF_MAP_TYPE_DEVMAP:
- if (func_id != BPF_FUNC_redirect_map)
+ case BPF_MAP_TYPE_DEVMAP_HASH:
+ if (func_id != BPF_FUNC_redirect_map &&
+ func_id != BPF_FUNC_map_lookup_elem)
goto error;
break;
/* Restrict bpf side of cpumap and xskmap, open when use-cases
* appear.
*/
case BPF_MAP_TYPE_CPUMAP:
- case BPF_MAP_TYPE_XSKMAP:
if (func_id != BPF_FUNC_redirect_map)
goto error;
break;
+ case BPF_MAP_TYPE_XSKMAP:
+ if (func_id != BPF_FUNC_redirect_map &&
+ func_id != BPF_FUNC_map_lookup_elem)
+ goto error;
+ break;
case BPF_MAP_TYPE_ARRAY_OF_MAPS:
case BPF_MAP_TYPE_HASH_OF_MAPS:
if (func_id != BPF_FUNC_map_lookup_elem)
@@ -2172,6 +3503,18 @@
if (func_id != BPF_FUNC_sk_select_reuseport)
goto error;
break;
+ case BPF_MAP_TYPE_QUEUE:
+ case BPF_MAP_TYPE_STACK:
+ if (func_id != BPF_FUNC_map_peek_elem &&
+ func_id != BPF_FUNC_map_pop_elem &&
+ func_id != BPF_FUNC_map_push_elem)
+ goto error;
+ break;
+ case BPF_MAP_TYPE_SK_STORAGE:
+ if (func_id != BPF_FUNC_sk_storage_get &&
+ func_id != BPF_FUNC_sk_storage_delete)
+ goto error;
+ break;
default:
break;
}
@@ -2203,6 +3546,7 @@
break;
case BPF_FUNC_redirect_map:
if (map->map_type != BPF_MAP_TYPE_DEVMAP &&
+ map->map_type != BPF_MAP_TYPE_DEVMAP_HASH &&
map->map_type != BPF_MAP_TYPE_CPUMAP &&
map->map_type != BPF_MAP_TYPE_XSKMAP)
goto error;
@@ -2220,13 +3564,26 @@
goto error;
break;
case BPF_FUNC_get_local_storage:
- if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE)
+ if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
+ map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
goto error;
break;
case BPF_FUNC_sk_select_reuseport:
if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY)
goto error;
break;
+ case BPF_FUNC_map_peek_elem:
+ case BPF_FUNC_map_pop_elem:
+ case BPF_FUNC_map_push_elem:
+ if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+ map->map_type != BPF_MAP_TYPE_STACK)
+ goto error;
+ break;
+ case BPF_FUNC_sk_storage_get:
+ case BPF_FUNC_sk_storage_delete:
+ if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
+ goto error;
+ break;
default:
break;
}
@@ -2287,10 +3644,38 @@
return true;
}
-static int check_func_proto(const struct bpf_func_proto *fn)
+static bool check_refcount_ok(const struct bpf_func_proto *fn, int func_id)
+{
+ int count = 0;
+
+ if (arg_type_may_be_refcounted(fn->arg1_type))
+ count++;
+ if (arg_type_may_be_refcounted(fn->arg2_type))
+ count++;
+ if (arg_type_may_be_refcounted(fn->arg3_type))
+ count++;
+ if (arg_type_may_be_refcounted(fn->arg4_type))
+ count++;
+ if (arg_type_may_be_refcounted(fn->arg5_type))
+ count++;
+
+ /* A reference acquiring function cannot acquire
+ * another refcounted ptr.
+ */
+ if (is_acquire_function(func_id) && count)
+ return false;
+
+ /* We only support one arg being unreferenced at the moment,
+ * which is sufficient for the helper functions we have right now.
+ */
+ return count <= 1;
+}
+
+static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
{
return check_raw_mode_ok(fn) &&
- check_arg_pair_ok(fn) ? 0 : -EINVAL;
+ check_arg_pair_ok(fn) &&
+ check_refcount_ok(fn, func_id) ? 0 : -EINVAL;
}
/* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
@@ -2306,10 +3691,9 @@
if (reg_is_pkt_pointer_any(®s[i]))
mark_reg_unknown(env, regs, i);
- for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
- if (state->stack[i].slot_type[0] != STACK_SPILL)
+ bpf_for_each_spilled_reg(i, state, reg) {
+ if (!reg)
continue;
- reg = &state->stack[i].spilled_ptr;
if (reg_is_pkt_pointer_any(reg))
__mark_reg_unknown(reg);
}
@@ -2324,12 +3708,51 @@
__clear_all_pkt_pointers(env, vstate->frame[i]);
}
+static void release_reg_references(struct bpf_verifier_env *env,
+ struct bpf_func_state *state,
+ int ref_obj_id)
+{
+ struct bpf_reg_state *regs = state->regs, *reg;
+ int i;
+
+ for (i = 0; i < MAX_BPF_REG; i++)
+ if (regs[i].ref_obj_id == ref_obj_id)
+ mark_reg_unknown(env, regs, i);
+
+ bpf_for_each_spilled_reg(i, state, reg) {
+ if (!reg)
+ continue;
+ if (reg->ref_obj_id == ref_obj_id)
+ __mark_reg_unknown(reg);
+ }
+}
+
+/* The pointer with the specified id has released its reference to kernel
+ * resources. Identify all copies of the same pointer and clear the reference.
+ */
+static int release_reference(struct bpf_verifier_env *env,
+ int ref_obj_id)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ int err;
+ int i;
+
+ err = release_reference_state(cur_func(env), ref_obj_id);
+ if (err)
+ return err;
+
+ for (i = 0; i <= vstate->curframe; i++)
+ release_reg_references(env, vstate->frame[i], ref_obj_id);
+
+ return 0;
+}
+
static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
int *insn_idx)
{
struct bpf_verifier_state *state = env->cur_state;
struct bpf_func_state *caller, *callee;
- int i, subprog, target_insn;
+ int i, err, subprog, target_insn;
if (state->curframe + 1 >= MAX_CALL_FRAMES) {
verbose(env, "the call stack of %d frames is too deep\n",
@@ -2367,11 +3790,18 @@
state->curframe + 1 /* frameno within this callchain */,
subprog /* subprog number within this prog */);
- /* copy r1 - r5 args that callee can access */
+ /* Transfer references to the callee */
+ err = transfer_reference_state(callee, caller);
+ if (err)
+ return err;
+
+ /* copy r1 - r5 args that callee can access. The copy includes parent
+ * pointers, which connects us up to the liveness chain
+ */
for (i = BPF_REG_1; i <= BPF_REG_5; i++)
callee->regs[i] = caller->regs[i];
- /* after the call regsiters r0 - r5 were scratched */
+ /* after the call registers r0 - r5 were scratched */
for (i = 0; i < CALLER_SAVED_REGS; i++) {
mark_reg_not_init(env, caller->regs, caller_saved[i]);
check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
@@ -2383,7 +3813,7 @@
/* and go analyze first insn of the callee */
*insn_idx = target_insn;
- if (env->log.level) {
+ if (env->log.level & BPF_LOG_LEVEL) {
verbose(env, "caller:\n");
print_verifier_state(env, caller);
verbose(env, "callee:\n");
@@ -2397,6 +3827,7 @@
struct bpf_verifier_state *state = env->cur_state;
struct bpf_func_state *caller, *callee;
struct bpf_reg_state *r0;
+ int err;
callee = state->frame[state->curframe];
r0 = &callee->regs[BPF_REG_0];
@@ -2416,8 +3847,13 @@
/* return to the caller whatever r0 had in the callee */
caller->regs[BPF_REG_0] = *r0;
+ /* Transfer references to the caller */
+ err = transfer_reference_state(caller, callee);
+ if (err)
+ return err;
+
*insn_idx = callee->callsite + 1;
- if (env->log.level) {
+ if (env->log.level & BPF_LOG_LEVEL) {
verbose(env, "returning from callee:\n");
print_verifier_state(env, callee);
verbose(env, "to caller at %d:\n", *insn_idx);
@@ -2451,18 +3887,35 @@
int func_id, int insn_idx)
{
struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+ struct bpf_map *map = meta->map_ptr;
if (func_id != BPF_FUNC_tail_call &&
func_id != BPF_FUNC_map_lookup_elem &&
func_id != BPF_FUNC_map_update_elem &&
- func_id != BPF_FUNC_map_delete_elem)
+ func_id != BPF_FUNC_map_delete_elem &&
+ func_id != BPF_FUNC_map_push_elem &&
+ func_id != BPF_FUNC_map_pop_elem &&
+ func_id != BPF_FUNC_map_peek_elem)
return 0;
- if (meta->map_ptr == NULL) {
+ if (map == NULL) {
verbose(env, "kernel subsystem misconfigured verifier\n");
return -EINVAL;
}
+ /* In case of read-only, some additional restrictions
+ * need to be applied in order to prevent altering the
+ * state of the map from program side.
+ */
+ if ((map->map_flags & BPF_F_RDONLY_PROG) &&
+ (func_id == BPF_FUNC_map_delete_elem ||
+ func_id == BPF_FUNC_map_update_elem ||
+ func_id == BPF_FUNC_map_push_elem ||
+ func_id == BPF_FUNC_map_pop_elem)) {
+ verbose(env, "write into map forbidden\n");
+ return -EACCES;
+ }
+
if (!BPF_MAP_PTR(aux->map_state))
bpf_map_ptr_store(aux, meta->map_ptr,
meta->map_ptr->unpriv_array);
@@ -2472,6 +3925,18 @@
return 0;
}
+static int check_reference_leak(struct bpf_verifier_env *env)
+{
+ struct bpf_func_state *state = cur_func(env);
+ int i;
+
+ for (i = 0; i < state->acquired_refs; i++) {
+ verbose(env, "Unreleased reference id=%d alloc_insn=%d\n",
+ state->refs[i].id, state->refs[i].insn_idx);
+ }
+ return state->acquired_refs ? -EINVAL : 0;
+}
+
static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
{
const struct bpf_func_proto *fn = NULL;
@@ -2512,13 +3977,14 @@
memset(&meta, 0, sizeof(meta));
meta.pkt_access = fn->pkt_access;
- err = check_func_proto(fn);
+ err = check_func_proto(fn, func_id);
if (err) {
verbose(env, "kernel subsystem misconfigured func %s#%d\n",
func_id_name(func_id), func_id);
return err;
}
+ meta.func_id = func_id;
/* check args */
err = check_func_arg(env, BPF_REG_1, fn->arg1_type, &meta);
if (err)
@@ -2550,6 +4016,21 @@
return err;
}
+ if (func_id == BPF_FUNC_tail_call) {
+ err = check_reference_leak(env);
+ if (err) {
+ verbose(env, "tail_call would lead to reference leak\n");
+ return err;
+ }
+ } else if (is_release_function(func_id)) {
+ err = release_reference(env, meta.ref_obj_id);
+ if (err) {
+ verbose(env, "func %s#%d reference has not been acquired before\n",
+ func_id_name(func_id), func_id);
+ return err;
+ }
+ }
+
regs = cur_regs(env);
/* check that flags argument in get_local_storage(map, flags) is 0,
@@ -2567,6 +4048,9 @@
check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
}
+ /* helper call returns 64-bit value. */
+ regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+
/* update return register (already marked as written above) */
if (fn->ret_type == RET_INTEGER) {
/* sets type to SCALAR_VALUE */
@@ -2575,10 +4059,6 @@
regs[BPF_REG_0].type = NOT_INIT;
} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL ||
fn->ret_type == RET_PTR_TO_MAP_VALUE) {
- if (fn->ret_type == RET_PTR_TO_MAP_VALUE)
- regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
- else
- regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
/* There is no offset yet applied, variable or fixed */
mark_reg_known_zero(env, regs, BPF_REG_0);
/* remember map_ptr, so that check_map_access()
@@ -2591,6 +4071,25 @@
return -EINVAL;
}
regs[BPF_REG_0].map_ptr = meta.map_ptr;
+ if (fn->ret_type == RET_PTR_TO_MAP_VALUE) {
+ regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
+ if (map_value_has_spin_lock(meta.map_ptr))
+ regs[BPF_REG_0].id = ++env->id_gen;
+ } else {
+ regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
+ regs[BPF_REG_0].id = ++env->id_gen;
+ }
+ } else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) {
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL;
+ regs[BPF_REG_0].id = ++env->id_gen;
+ } else if (fn->ret_type == RET_PTR_TO_SOCK_COMMON_OR_NULL) {
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL;
+ regs[BPF_REG_0].id = ++env->id_gen;
+ } else if (fn->ret_type == RET_PTR_TO_TCP_SOCK_OR_NULL) {
+ mark_reg_known_zero(env, regs, BPF_REG_0);
+ regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL;
regs[BPF_REG_0].id = ++env->id_gen;
} else {
verbose(env, "unknown return type %d of func %s#%d\n",
@@ -2598,6 +4097,20 @@
return -EINVAL;
}
+ if (is_ptr_cast_function(func_id)) {
+ /* For release_reference() */
+ regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+ } else if (is_acquire_function(func_id)) {
+ int id = acquire_reference_state(env, insn_idx);
+
+ if (id < 0)
+ return id;
+ /* For mark_ptr_or_null_reg() */
+ regs[BPF_REG_0].id = id;
+ /* For release_reference() */
+ regs[BPF_REG_0].ref_obj_id = id;
+ }
+
do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
err = check_map_func_compatibility(env, meta.map_ptr, func_id);
@@ -2682,6 +4195,128 @@
return true;
}
+static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env)
+{
+ return &env->insn_aux_data[env->insn_idx];
+}
+
+static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
+ u32 *ptr_limit, u8 opcode, bool off_is_neg)
+{
+ bool mask_to_left = (opcode == BPF_ADD && off_is_neg) ||
+ (opcode == BPF_SUB && !off_is_neg);
+ u32 off;
+
+ switch (ptr_reg->type) {
+ case PTR_TO_STACK:
+ /* Indirect variable offset stack access is prohibited in
+ * unprivileged mode so it's not handled here.
+ */
+ off = ptr_reg->off + ptr_reg->var_off.value;
+ if (mask_to_left)
+ *ptr_limit = MAX_BPF_STACK + off;
+ else
+ *ptr_limit = -off;
+ return 0;
+ case PTR_TO_MAP_VALUE:
+ if (mask_to_left) {
+ *ptr_limit = ptr_reg->umax_value + ptr_reg->off;
+ } else {
+ off = ptr_reg->smin_value + ptr_reg->off;
+ *ptr_limit = ptr_reg->map_ptr->value_size - off;
+ }
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env,
+ const struct bpf_insn *insn)
+{
+ return env->allow_ptr_leaks || BPF_SRC(insn->code) == BPF_K;
+}
+
+static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux,
+ u32 alu_state, u32 alu_limit)
+{
+ /* If we arrived here from different branches with different
+ * state or limits to sanitize, then this won't work.
+ */
+ if (aux->alu_state &&
+ (aux->alu_state != alu_state ||
+ aux->alu_limit != alu_limit))
+ return -EACCES;
+
+ /* Corresponding fixup done in fixup_bpf_calls(). */
+ aux->alu_state = alu_state;
+ aux->alu_limit = alu_limit;
+ return 0;
+}
+
+static int sanitize_val_alu(struct bpf_verifier_env *env,
+ struct bpf_insn *insn)
+{
+ struct bpf_insn_aux_data *aux = cur_aux(env);
+
+ if (can_skip_alu_sanitation(env, insn))
+ return 0;
+
+ return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
+}
+
+static int sanitize_ptr_alu(struct bpf_verifier_env *env,
+ struct bpf_insn *insn,
+ const struct bpf_reg_state *ptr_reg,
+ struct bpf_reg_state *dst_reg,
+ bool off_is_neg)
+{
+ struct bpf_verifier_state *vstate = env->cur_state;
+ struct bpf_insn_aux_data *aux = cur_aux(env);
+ bool ptr_is_dst_reg = ptr_reg == dst_reg;
+ u8 opcode = BPF_OP(insn->code);
+ u32 alu_state, alu_limit;
+ struct bpf_reg_state tmp;
+ bool ret;
+
+ if (can_skip_alu_sanitation(env, insn))
+ return 0;
+
+ /* We already marked aux for masking from non-speculative
+ * paths, thus we got here in the first place. We only care
+ * to explore bad access from here.
+ */
+ if (vstate->speculative)
+ goto do_sim;
+
+ alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
+ alu_state |= ptr_is_dst_reg ?
+ BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
+
+ if (retrieve_ptr_limit(ptr_reg, &alu_limit, opcode, off_is_neg))
+ return 0;
+ if (update_alu_sanitation_state(aux, alu_state, alu_limit))
+ return -EACCES;
+do_sim:
+ /* Simulate and find potential out-of-bounds access under
+ * speculative execution from truncation as a result of
+ * masking when off was not within expected range. If off
+ * sits in dst, then we temporarily need to move ptr there
+ * to simulate dst (== 0) +/-= ptr. Needed, for example,
+ * for cases where we use K-based arithmetic in one direction
+ * and truncated reg-based in the other in order to explore
+ * bad access.
+ */
+ if (!ptr_is_dst_reg) {
+ tmp = *dst_reg;
+ *dst_reg = *ptr_reg;
+ }
+ ret = push_stack(env, env->insn_idx + 1, env->insn_idx, true);
+ if (!ptr_is_dst_reg && ret)
+ *dst_reg = tmp;
+ return !ret ? -EFAULT : 0;
+}
+
/* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
* Caller should also handle BPF_MOV case separately.
* If we return -EACCES, caller may want to try again treating pointer as a
@@ -2700,8 +4335,9 @@
smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
+ u32 dst = insn->dst_reg, src = insn->src_reg;
u8 opcode = BPF_OP(insn->code);
- u32 dst = insn->dst_reg;
+ int ret;
dst_reg = ®s[dst];
@@ -2722,20 +4358,32 @@
return -EACCES;
}
- if (ptr_reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
- verbose(env, "R%d pointer arithmetic on PTR_TO_MAP_VALUE_OR_NULL prohibited, null-check it first\n",
- dst);
+ switch (ptr_reg->type) {
+ case PTR_TO_MAP_VALUE_OR_NULL:
+ verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
+ dst, reg_type_str[ptr_reg->type]);
return -EACCES;
- }
- if (ptr_reg->type == CONST_PTR_TO_MAP) {
- verbose(env, "R%d pointer arithmetic on CONST_PTR_TO_MAP prohibited\n",
- dst);
+ case CONST_PTR_TO_MAP:
+ case PTR_TO_PACKET_END:
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCKET_OR_NULL:
+ case PTR_TO_SOCK_COMMON:
+ case PTR_TO_SOCK_COMMON_OR_NULL:
+ case PTR_TO_TCP_SOCK:
+ case PTR_TO_TCP_SOCK_OR_NULL:
+ case PTR_TO_XDP_SOCK:
+ verbose(env, "R%d pointer arithmetic on %s prohibited\n",
+ dst, reg_type_str[ptr_reg->type]);
return -EACCES;
- }
- if (ptr_reg->type == PTR_TO_PACKET_END) {
- verbose(env, "R%d pointer arithmetic on PTR_TO_PACKET_END prohibited\n",
- dst);
- return -EACCES;
+ case PTR_TO_MAP_VALUE:
+ if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) {
+ verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n",
+ off_reg == dst_reg ? dst : src);
+ return -EACCES;
+ }
+ /* fall-through */
+ default:
+ break;
}
/* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
@@ -2750,6 +4398,11 @@
switch (opcode) {
case BPF_ADD:
+ ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0);
+ if (ret < 0) {
+ verbose(env, "R%d tried to add from different maps or paths\n", dst);
+ return ret;
+ }
/* We can take a fixed offset as long as it doesn't overflow
* the s32 'off' field
*/
@@ -2800,6 +4453,11 @@
}
break;
case BPF_SUB:
+ ret = sanitize_ptr_alu(env, insn, ptr_reg, dst_reg, smin_val < 0);
+ if (ret < 0) {
+ verbose(env, "R%d tried to sub from different maps or paths\n", dst);
+ return ret;
+ }
if (dst_reg == off_reg) {
/* scalar -= pointer. Creates an unknown scalar */
verbose(env, "R%d tried to subtract pointer from scalar\n",
@@ -2879,6 +4537,25 @@
__update_reg_bounds(dst_reg);
__reg_deduce_bounds(dst_reg);
__reg_bound_offset(dst_reg);
+
+ /* For unprivileged we require that resulting offset must be in bounds
+ * in order to be able to sanitize access later on.
+ */
+ if (!env->allow_ptr_leaks) {
+ if (dst_reg->type == PTR_TO_MAP_VALUE &&
+ check_map_access(env, dst, dst_reg->off, 1, false)) {
+ verbose(env, "R%d pointer arithmetic of map value goes out of range, "
+ "prohibited for !root\n", dst);
+ return -EACCES;
+ } else if (dst_reg->type == PTR_TO_STACK &&
+ check_stack_access(env, dst_reg, dst_reg->off +
+ dst_reg->var_off.value, 1)) {
+ verbose(env, "R%d stack pointer arithmetic goes out of range, "
+ "prohibited for !root\n", dst);
+ return -EACCES;
+ }
+ }
+
return 0;
}
@@ -2897,6 +4574,8 @@
s64 smin_val, smax_val;
u64 umin_val, umax_val;
u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
+ u32 dst = insn->dst_reg;
+ int ret;
if (insn_bitness == 32) {
/* Relevant for 32-bit RSH: Information can propagate towards
@@ -2931,6 +4610,11 @@
switch (opcode) {
case BPF_ADD:
+ ret = sanitize_val_alu(env, insn);
+ if (ret < 0) {
+ verbose(env, "R%d tried to add from different pointers or scalars\n", dst);
+ return ret;
+ }
if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
signed_add_overflows(dst_reg->smax_value, smax_val)) {
dst_reg->smin_value = S64_MIN;
@@ -2950,6 +4634,11 @@
dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off);
break;
case BPF_SUB:
+ ret = sanitize_val_alu(env, insn);
+ if (ret < 0) {
+ verbose(env, "R%d tried to sub from different pointers or scalars\n", dst);
+ return ret;
+ }
if (signed_sub_overflows(dst_reg->smin_value, smax_val) ||
signed_sub_overflows(dst_reg->smax_value, smin_val)) {
/* Overflow possible, we know nothing */
@@ -3160,6 +4849,7 @@
struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg;
struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
u8 opcode = BPF_OP(insn->code);
+ int err;
dst_reg = ®s[insn->dst_reg];
src_reg = NULL;
@@ -3186,11 +4876,17 @@
* This is legal, but we have to reverse our
* src/dest handling in computing the range
*/
+ err = mark_chain_precision(env, insn->dst_reg);
+ if (err)
+ return err;
return adjust_ptr_min_max_vals(env, insn,
src_reg, dst_reg);
}
} else if (ptr_reg) {
/* pointer += scalar */
+ err = mark_chain_precision(env, insn->src_reg);
+ if (err)
+ return err;
return adjust_ptr_min_max_vals(env, insn,
dst_reg, src_reg);
}
@@ -3285,12 +4981,16 @@
return err;
if (BPF_SRC(insn->code) == BPF_X) {
+ struct bpf_reg_state *src_reg = regs + insn->src_reg;
+ struct bpf_reg_state *dst_reg = regs + insn->dst_reg;
+
if (BPF_CLASS(insn->code) == BPF_ALU64) {
/* case: R1 = R2
* copy register state to dest reg
*/
- regs[insn->dst_reg] = regs[insn->src_reg];
- regs[insn->dst_reg].live |= REG_LIVE_WRITTEN;
+ *dst_reg = *src_reg;
+ dst_reg->live |= REG_LIVE_WRITTEN;
+ dst_reg->subreg_def = DEF_NOT_SUBREG;
} else {
/* R1 = (u32) R2 */
if (is_pointer_value(env, insn->src_reg)) {
@@ -3298,9 +4998,15 @@
"R%d partial copy of pointer\n",
insn->src_reg);
return -EACCES;
+ } else if (src_reg->type == SCALAR_VALUE) {
+ *dst_reg = *src_reg;
+ dst_reg->live |= REG_LIVE_WRITTEN;
+ dst_reg->subreg_def = env->insn_idx + 1;
+ } else {
+ mark_reg_unknown(env, regs,
+ insn->dst_reg);
}
- mark_reg_unknown(env, regs, insn->dst_reg);
- coerce_reg_to_size(®s[insn->dst_reg], 4);
+ coerce_reg_to_size(dst_reg, 4);
}
} else {
/* case: R = imm
@@ -3351,11 +5057,6 @@
return -EINVAL;
}
- if (opcode == BPF_ARSH && BPF_CLASS(insn->code) != BPF_ALU64) {
- verbose(env, "BPF_ARSH not supported for 32 bit ALU\n");
- return -EINVAL;
- }
-
if ((opcode == BPF_LSH || opcode == BPF_RSH ||
opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
@@ -3377,15 +5078,35 @@
return 0;
}
+static void __find_good_pkt_pointers(struct bpf_func_state *state,
+ struct bpf_reg_state *dst_reg,
+ enum bpf_reg_type type, u16 new_range)
+{
+ struct bpf_reg_state *reg;
+ int i;
+
+ for (i = 0; i < MAX_BPF_REG; i++) {
+ reg = &state->regs[i];
+ if (reg->type == type && reg->id == dst_reg->id)
+ /* keep the maximum range already checked */
+ reg->range = max(reg->range, new_range);
+ }
+
+ bpf_for_each_spilled_reg(i, state, reg) {
+ if (!reg)
+ continue;
+ if (reg->type == type && reg->id == dst_reg->id)
+ reg->range = max(reg->range, new_range);
+ }
+}
+
static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
struct bpf_reg_state *dst_reg,
enum bpf_reg_type type,
bool range_right_open)
{
- struct bpf_func_state *state = vstate->frame[vstate->curframe];
- struct bpf_reg_state *regs = state->regs, *reg;
u16 new_range;
- int i, j;
+ int i;
if (dst_reg->off < 0 ||
(dst_reg->off == 0 && range_right_open))
@@ -3450,21 +5171,150 @@
* the range won't allow anything.
* dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
*/
- for (i = 0; i < MAX_BPF_REG; i++)
- if (regs[i].type == type && regs[i].id == dst_reg->id)
- /* keep the maximum range already checked */
- regs[i].range = max(regs[i].range, new_range);
+ for (i = 0; i <= vstate->curframe; i++)
+ __find_good_pkt_pointers(vstate->frame[i], dst_reg, type,
+ new_range);
+}
- for (j = 0; j <= vstate->curframe; j++) {
- state = vstate->frame[j];
- for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
- if (state->stack[i].slot_type[0] != STACK_SPILL)
- continue;
- reg = &state->stack[i].spilled_ptr;
- if (reg->type == type && reg->id == dst_reg->id)
- reg->range = max(reg->range, new_range);
+/* compute branch direction of the expression "if (reg opcode val) goto target;"
+ * and return:
+ * 1 - branch will be taken and "goto target" will be executed
+ * 0 - branch will not be taken and fall-through to next insn
+ * -1 - unknown. Example: "if (reg < 5)" is unknown when register value range [0,10]
+ */
+static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode,
+ bool is_jmp32)
+{
+ struct bpf_reg_state reg_lo;
+ s64 sval;
+
+ if (__is_pointer_value(false, reg))
+ return -1;
+
+ if (is_jmp32) {
+ reg_lo = *reg;
+ reg = ®_lo;
+ /* For JMP32, only low 32 bits are compared, coerce_reg_to_size
+ * could truncate high bits and update umin/umax according to
+ * information of low bits.
+ */
+ coerce_reg_to_size(reg, 4);
+ /* smin/smax need special handling. For example, after coerce,
+ * if smin_value is 0x00000000ffffffffLL, the value is -1 when
+ * used as operand to JMP32. It is a negative number from s32's
+ * point of view, while it is a positive number when seen as
+ * s64. The smin/smax are kept as s64, therefore, when used with
+ * JMP32, they need to be transformed into s32, then sign
+ * extended back to s64.
+ *
+ * Also, smin/smax were copied from umin/umax. If umin/umax has
+ * different sign bit, then min/max relationship doesn't
+ * maintain after casting into s32, for this case, set smin/smax
+ * to safest range.
+ */
+ if ((reg->umax_value ^ reg->umin_value) &
+ (1ULL << 31)) {
+ reg->smin_value = S32_MIN;
+ reg->smax_value = S32_MAX;
}
+ reg->smin_value = (s64)(s32)reg->smin_value;
+ reg->smax_value = (s64)(s32)reg->smax_value;
+
+ val = (u32)val;
+ sval = (s64)(s32)val;
+ } else {
+ sval = (s64)val;
}
+
+ switch (opcode) {
+ case BPF_JEQ:
+ if (tnum_is_const(reg->var_off))
+ return !!tnum_equals_const(reg->var_off, val);
+ break;
+ case BPF_JNE:
+ if (tnum_is_const(reg->var_off))
+ return !tnum_equals_const(reg->var_off, val);
+ break;
+ case BPF_JSET:
+ if ((~reg->var_off.mask & reg->var_off.value) & val)
+ return 1;
+ if (!((reg->var_off.mask | reg->var_off.value) & val))
+ return 0;
+ break;
+ case BPF_JGT:
+ if (reg->umin_value > val)
+ return 1;
+ else if (reg->umax_value <= val)
+ return 0;
+ break;
+ case BPF_JSGT:
+ if (reg->smin_value > sval)
+ return 1;
+ else if (reg->smax_value < sval)
+ return 0;
+ break;
+ case BPF_JLT:
+ if (reg->umax_value < val)
+ return 1;
+ else if (reg->umin_value >= val)
+ return 0;
+ break;
+ case BPF_JSLT:
+ if (reg->smax_value < sval)
+ return 1;
+ else if (reg->smin_value >= sval)
+ return 0;
+ break;
+ case BPF_JGE:
+ if (reg->umin_value >= val)
+ return 1;
+ else if (reg->umax_value < val)
+ return 0;
+ break;
+ case BPF_JSGE:
+ if (reg->smin_value >= sval)
+ return 1;
+ else if (reg->smax_value < sval)
+ return 0;
+ break;
+ case BPF_JLE:
+ if (reg->umax_value <= val)
+ return 1;
+ else if (reg->umin_value > val)
+ return 0;
+ break;
+ case BPF_JSLE:
+ if (reg->smax_value <= sval)
+ return 1;
+ else if (reg->smin_value > sval)
+ return 0;
+ break;
+ }
+
+ return -1;
+}
+
+/* Generate min value of the high 32-bit from TNUM info. */
+static u64 gen_hi_min(struct tnum var)
+{
+ return var.value & ~0xffffffffULL;
+}
+
+/* Generate max value of the high 32-bit from TNUM info. */
+static u64 gen_hi_max(struct tnum var)
+{
+ return (var.value | var.mask) & ~0xffffffffULL;
+}
+
+/* Return true if VAL is compared with a s64 sign extended from s32, and they
+ * are with the same signedness.
+ */
+static bool cmp_val_with_extended_s64(s64 sval, struct bpf_reg_state *reg)
+{
+ return ((s32)sval >= 0 &&
+ reg->smin_value >= 0 && reg->smax_value <= S32_MAX) ||
+ ((s32)sval < 0 &&
+ reg->smax_value <= 0 && reg->smin_value >= S32_MIN);
}
/* Adjusts the register min/max values in the case that the dst_reg is the
@@ -3474,8 +5324,10 @@
*/
static void reg_set_min_max(struct bpf_reg_state *true_reg,
struct bpf_reg_state *false_reg, u64 val,
- u8 opcode)
+ u8 opcode, bool is_jmp32)
{
+ s64 sval;
+
/* If the dst_reg is a pointer, we can't learn anything about its
* variable offset from the compare (unless src_reg were a pointer into
* the same object, but we don't bother with that.
@@ -3485,51 +5337,93 @@
if (__is_pointer_value(false, false_reg))
return;
+ val = is_jmp32 ? (u32)val : val;
+ sval = is_jmp32 ? (s64)(s32)val : (s64)val;
+
switch (opcode) {
case BPF_JEQ:
- /* If this is false then we know nothing Jon Snow, but if it is
- * true then we know for sure.
- */
- __mark_reg_known(true_reg, val);
- break;
case BPF_JNE:
- /* If this is true we know nothing Jon Snow, but if it is false
- * we know the value for sure;
+ {
+ struct bpf_reg_state *reg =
+ opcode == BPF_JEQ ? true_reg : false_reg;
+
+ /* For BPF_JEQ, if this is false we know nothing Jon Snow, but
+ * if it is true we know the value for sure. Likewise for
+ * BPF_JNE.
*/
- __mark_reg_known(false_reg, val);
+ if (is_jmp32) {
+ u64 old_v = reg->var_off.value;
+ u64 hi_mask = ~0xffffffffULL;
+
+ reg->var_off.value = (old_v & hi_mask) | val;
+ reg->var_off.mask &= hi_mask;
+ } else {
+ __mark_reg_known(reg, val);
+ }
break;
- case BPF_JGT:
- false_reg->umax_value = min(false_reg->umax_value, val);
- true_reg->umin_value = max(true_reg->umin_value, val + 1);
- break;
- case BPF_JSGT:
- false_reg->smax_value = min_t(s64, false_reg->smax_value, val);
- true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1);
- break;
- case BPF_JLT:
- false_reg->umin_value = max(false_reg->umin_value, val);
- true_reg->umax_value = min(true_reg->umax_value, val - 1);
- break;
- case BPF_JSLT:
- false_reg->smin_value = max_t(s64, false_reg->smin_value, val);
- true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1);
+ }
+ case BPF_JSET:
+ false_reg->var_off = tnum_and(false_reg->var_off,
+ tnum_const(~val));
+ if (is_power_of_2(val))
+ true_reg->var_off = tnum_or(true_reg->var_off,
+ tnum_const(val));
break;
case BPF_JGE:
- false_reg->umax_value = min(false_reg->umax_value, val - 1);
- true_reg->umin_value = max(true_reg->umin_value, val);
+ case BPF_JGT:
+ {
+ u64 false_umax = opcode == BPF_JGT ? val : val - 1;
+ u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
+
+ if (is_jmp32) {
+ false_umax += gen_hi_max(false_reg->var_off);
+ true_umin += gen_hi_min(true_reg->var_off);
+ }
+ false_reg->umax_value = min(false_reg->umax_value, false_umax);
+ true_reg->umin_value = max(true_reg->umin_value, true_umin);
break;
+ }
case BPF_JSGE:
- false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1);
- true_reg->smin_value = max_t(s64, true_reg->smin_value, val);
+ case BPF_JSGT:
+ {
+ s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1;
+ s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;
+
+ /* If the full s64 was not sign-extended from s32 then don't
+ * deduct further info.
+ */
+ if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
+ break;
+ false_reg->smax_value = min(false_reg->smax_value, false_smax);
+ true_reg->smin_value = max(true_reg->smin_value, true_smin);
break;
+ }
case BPF_JLE:
- false_reg->umin_value = max(false_reg->umin_value, val + 1);
- true_reg->umax_value = min(true_reg->umax_value, val);
+ case BPF_JLT:
+ {
+ u64 false_umin = opcode == BPF_JLT ? val : val + 1;
+ u64 true_umax = opcode == BPF_JLT ? val - 1 : val;
+
+ if (is_jmp32) {
+ false_umin += gen_hi_min(false_reg->var_off);
+ true_umax += gen_hi_max(true_reg->var_off);
+ }
+ false_reg->umin_value = max(false_reg->umin_value, false_umin);
+ true_reg->umax_value = min(true_reg->umax_value, true_umax);
break;
+ }
case BPF_JSLE:
- false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1);
- true_reg->smax_value = min_t(s64, true_reg->smax_value, val);
+ case BPF_JSLT:
+ {
+ s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1;
+ s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;
+
+ if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
+ break;
+ false_reg->smin_value = max(false_reg->smin_value, false_smin);
+ true_reg->smax_value = min(true_reg->smax_value, true_smax);
break;
+ }
default:
break;
}
@@ -3552,56 +5446,93 @@
*/
static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
struct bpf_reg_state *false_reg, u64 val,
- u8 opcode)
+ u8 opcode, bool is_jmp32)
{
+ s64 sval;
+
if (__is_pointer_value(false, false_reg))
return;
+ val = is_jmp32 ? (u32)val : val;
+ sval = is_jmp32 ? (s64)(s32)val : (s64)val;
+
switch (opcode) {
case BPF_JEQ:
- /* If this is false then we know nothing Jon Snow, but if it is
- * true then we know for sure.
- */
- __mark_reg_known(true_reg, val);
- break;
case BPF_JNE:
- /* If this is true we know nothing Jon Snow, but if it is false
- * we know the value for sure;
- */
- __mark_reg_known(false_reg, val);
+ {
+ struct bpf_reg_state *reg =
+ opcode == BPF_JEQ ? true_reg : false_reg;
+
+ if (is_jmp32) {
+ u64 old_v = reg->var_off.value;
+ u64 hi_mask = ~0xffffffffULL;
+
+ reg->var_off.value = (old_v & hi_mask) | val;
+ reg->var_off.mask &= hi_mask;
+ } else {
+ __mark_reg_known(reg, val);
+ }
break;
- case BPF_JGT:
- true_reg->umax_value = min(true_reg->umax_value, val - 1);
- false_reg->umin_value = max(false_reg->umin_value, val);
- break;
- case BPF_JSGT:
- true_reg->smax_value = min_t(s64, true_reg->smax_value, val - 1);
- false_reg->smin_value = max_t(s64, false_reg->smin_value, val);
- break;
- case BPF_JLT:
- true_reg->umin_value = max(true_reg->umin_value, val + 1);
- false_reg->umax_value = min(false_reg->umax_value, val);
- break;
- case BPF_JSLT:
- true_reg->smin_value = max_t(s64, true_reg->smin_value, val + 1);
- false_reg->smax_value = min_t(s64, false_reg->smax_value, val);
+ }
+ case BPF_JSET:
+ false_reg->var_off = tnum_and(false_reg->var_off,
+ tnum_const(~val));
+ if (is_power_of_2(val))
+ true_reg->var_off = tnum_or(true_reg->var_off,
+ tnum_const(val));
break;
case BPF_JGE:
- true_reg->umax_value = min(true_reg->umax_value, val);
- false_reg->umin_value = max(false_reg->umin_value, val + 1);
+ case BPF_JGT:
+ {
+ u64 false_umin = opcode == BPF_JGT ? val : val + 1;
+ u64 true_umax = opcode == BPF_JGT ? val - 1 : val;
+
+ if (is_jmp32) {
+ false_umin += gen_hi_min(false_reg->var_off);
+ true_umax += gen_hi_max(true_reg->var_off);
+ }
+ false_reg->umin_value = max(false_reg->umin_value, false_umin);
+ true_reg->umax_value = min(true_reg->umax_value, true_umax);
break;
+ }
case BPF_JSGE:
- true_reg->smax_value = min_t(s64, true_reg->smax_value, val);
- false_reg->smin_value = max_t(s64, false_reg->smin_value, val + 1);
+ case BPF_JSGT:
+ {
+ s64 false_smin = opcode == BPF_JSGT ? sval : sval + 1;
+ s64 true_smax = opcode == BPF_JSGT ? sval - 1 : sval;
+
+ if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
+ break;
+ false_reg->smin_value = max(false_reg->smin_value, false_smin);
+ true_reg->smax_value = min(true_reg->smax_value, true_smax);
break;
+ }
case BPF_JLE:
- true_reg->umin_value = max(true_reg->umin_value, val);
- false_reg->umax_value = min(false_reg->umax_value, val - 1);
+ case BPF_JLT:
+ {
+ u64 false_umax = opcode == BPF_JLT ? val : val - 1;
+ u64 true_umin = opcode == BPF_JLT ? val + 1 : val;
+
+ if (is_jmp32) {
+ false_umax += gen_hi_max(false_reg->var_off);
+ true_umin += gen_hi_min(true_reg->var_off);
+ }
+ false_reg->umax_value = min(false_reg->umax_value, false_umax);
+ true_reg->umin_value = max(true_reg->umin_value, true_umin);
break;
+ }
case BPF_JSLE:
- true_reg->smin_value = max_t(s64, true_reg->smin_value, val);
- false_reg->smax_value = min_t(s64, false_reg->smax_value, val - 1);
+ case BPF_JSLT:
+ {
+ s64 false_smax = opcode == BPF_JSLT ? sval : sval - 1;
+ s64 true_smin = opcode == BPF_JSLT ? sval + 1 : sval;
+
+ if (is_jmp32 && !cmp_val_with_extended_s64(sval, false_reg))
+ break;
+ false_reg->smax_value = min(false_reg->smax_value, false_smax);
+ true_reg->smin_value = max(true_reg->smin_value, true_smin);
break;
+ }
default:
break;
}
@@ -3666,12 +5597,11 @@
}
}
-static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id,
- bool is_null)
+static void mark_ptr_or_null_reg(struct bpf_func_state *state,
+ struct bpf_reg_state *reg, u32 id,
+ bool is_null)
{
- struct bpf_reg_state *reg = ®s[regno];
-
- if (reg->type == PTR_TO_MAP_VALUE_OR_NULL && reg->id == id) {
+ if (reg_type_may_be_null(reg->type) && reg->id == id) {
/* Old offset (both fixed and variable parts) should
* have been known-zero, because we don't allow pointer
* arithmetic on pointers that might be NULL.
@@ -3684,42 +5614,79 @@
}
if (is_null) {
reg->type = SCALAR_VALUE;
- } else if (reg->map_ptr->inner_map_meta) {
- reg->type = CONST_PTR_TO_MAP;
- reg->map_ptr = reg->map_ptr->inner_map_meta;
- } else {
- reg->type = PTR_TO_MAP_VALUE;
+ } else if (reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
+ if (reg->map_ptr->inner_map_meta) {
+ reg->type = CONST_PTR_TO_MAP;
+ reg->map_ptr = reg->map_ptr->inner_map_meta;
+ } else if (reg->map_ptr->map_type ==
+ BPF_MAP_TYPE_XSKMAP) {
+ reg->type = PTR_TO_XDP_SOCK;
+ } else {
+ reg->type = PTR_TO_MAP_VALUE;
+ }
+ } else if (reg->type == PTR_TO_SOCKET_OR_NULL) {
+ reg->type = PTR_TO_SOCKET;
+ } else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) {
+ reg->type = PTR_TO_SOCK_COMMON;
+ } else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) {
+ reg->type = PTR_TO_TCP_SOCK;
}
- /* We don't need id from this point onwards anymore, thus we
- * should better reset it, so that state pruning has chances
- * to take effect.
- */
- reg->id = 0;
+ if (is_null) {
+ /* We don't need id and ref_obj_id from this point
+ * onwards anymore, thus we should better reset it,
+ * so that state pruning has chances to take effect.
+ */
+ reg->id = 0;
+ reg->ref_obj_id = 0;
+ } else if (!reg_may_point_to_spin_lock(reg)) {
+ /* For not-NULL ptr, reg->ref_obj_id will be reset
+ * in release_reg_references().
+ *
+ * reg->id is still used by spin_lock ptr. Other
+ * than spin_lock ptr type, reg->id can be reset.
+ */
+ reg->id = 0;
+ }
+ }
+}
+
+static void __mark_ptr_or_null_regs(struct bpf_func_state *state, u32 id,
+ bool is_null)
+{
+ struct bpf_reg_state *reg;
+ int i;
+
+ for (i = 0; i < MAX_BPF_REG; i++)
+ mark_ptr_or_null_reg(state, &state->regs[i], id, is_null);
+
+ bpf_for_each_spilled_reg(i, state, reg) {
+ if (!reg)
+ continue;
+ mark_ptr_or_null_reg(state, reg, id, is_null);
}
}
/* The logic is similar to find_good_pkt_pointers(), both could eventually
* be folded together at some point.
*/
-static void mark_map_regs(struct bpf_verifier_state *vstate, u32 regno,
- bool is_null)
+static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
+ bool is_null)
{
struct bpf_func_state *state = vstate->frame[vstate->curframe];
struct bpf_reg_state *regs = state->regs;
+ u32 ref_obj_id = regs[regno].ref_obj_id;
u32 id = regs[regno].id;
- int i, j;
+ int i;
- for (i = 0; i < MAX_BPF_REG; i++)
- mark_map_reg(regs, i, id, is_null);
+ if (ref_obj_id && ref_obj_id == id && is_null)
+ /* regs[regno] is in the " == NULL" branch.
+ * No one could have freed the reference state before
+ * doing the NULL check.
+ */
+ WARN_ON_ONCE(release_reference_state(state, id));
- for (j = 0; j <= vstate->curframe; j++) {
- state = vstate->frame[j];
- for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
- if (state->stack[i].slot_type[0] != STACK_SPILL)
- continue;
- mark_map_reg(&state->stack[i].spilled_ptr, 0, id, is_null);
- }
- }
+ for (i = 0; i <= vstate->curframe; i++)
+ __mark_ptr_or_null_regs(vstate->frame[i], id, is_null);
}
static bool try_match_pkt_pointers(const struct bpf_insn *insn,
@@ -3731,6 +5698,10 @@
if (BPF_SRC(insn->code) != BPF_X)
return false;
+ /* Pointers are always 64-bit. */
+ if (BPF_CLASS(insn->code) == BPF_JMP32)
+ return false;
+
switch (BPF_OP(insn->code)) {
case BPF_JGT:
if ((dst_reg->type == PTR_TO_PACKET &&
@@ -3821,18 +5792,21 @@
struct bpf_verifier_state *this_branch = env->cur_state;
struct bpf_verifier_state *other_branch;
struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
- struct bpf_reg_state *dst_reg, *other_branch_regs;
+ struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL;
u8 opcode = BPF_OP(insn->code);
+ bool is_jmp32;
+ int pred = -1;
int err;
- if (opcode > BPF_JSLE) {
- verbose(env, "invalid BPF_JMP opcode %x\n", opcode);
+ /* Only conditional jumps are expected to reach here. */
+ if (opcode == BPF_JA || opcode > BPF_JSLE) {
+ verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode);
return -EINVAL;
}
if (BPF_SRC(insn->code) == BPF_X) {
if (insn->imm != 0) {
- verbose(env, "BPF_JMP uses reserved fields\n");
+ verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
return -EINVAL;
}
@@ -3846,9 +5820,10 @@
insn->src_reg);
return -EACCES;
}
+ src_reg = ®s[insn->src_reg];
} else {
if (insn->src_reg != BPF_REG_0) {
- verbose(env, "BPF_JMP uses reserved fields\n");
+ verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
return -EINVAL;
}
}
@@ -3859,29 +5834,35 @@
return err;
dst_reg = ®s[insn->dst_reg];
+ is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
- /* detect if R == 0 where R was initialized to zero earlier */
- if (BPF_SRC(insn->code) == BPF_K &&
- (opcode == BPF_JEQ || opcode == BPF_JNE) &&
- dst_reg->type == SCALAR_VALUE &&
- tnum_is_const(dst_reg->var_off)) {
- if ((opcode == BPF_JEQ && dst_reg->var_off.value == insn->imm) ||
- (opcode == BPF_JNE && dst_reg->var_off.value != insn->imm)) {
- /* if (imm == imm) goto pc+off;
- * only follow the goto, ignore fall-through
- */
- *insn_idx += insn->off;
- return 0;
- } else {
- /* if (imm != imm) goto pc+off;
- * only follow fall-through branch, since
- * that's where the program will go
- */
- return 0;
- }
+ if (BPF_SRC(insn->code) == BPF_K)
+ pred = is_branch_taken(dst_reg, insn->imm,
+ opcode, is_jmp32);
+ else if (src_reg->type == SCALAR_VALUE &&
+ tnum_is_const(src_reg->var_off))
+ pred = is_branch_taken(dst_reg, src_reg->var_off.value,
+ opcode, is_jmp32);
+ if (pred >= 0) {
+ err = mark_chain_precision(env, insn->dst_reg);
+ if (BPF_SRC(insn->code) == BPF_X && !err)
+ err = mark_chain_precision(env, insn->src_reg);
+ if (err)
+ return err;
+ }
+ if (pred == 1) {
+ /* only follow the goto, ignore fall-through */
+ *insn_idx += insn->off;
+ return 0;
+ } else if (pred == 0) {
+ /* only follow fall-through branch, since
+ * that's where the program will go
+ */
+ return 0;
}
- other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx);
+ other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx,
+ false);
if (!other_branch)
return -EFAULT;
other_branch_regs = other_branch->frame[other_branch->curframe]->regs;
@@ -3894,37 +5875,60 @@
* comparable.
*/
if (BPF_SRC(insn->code) == BPF_X) {
+ struct bpf_reg_state *src_reg = ®s[insn->src_reg];
+ struct bpf_reg_state lo_reg0 = *dst_reg;
+ struct bpf_reg_state lo_reg1 = *src_reg;
+ struct bpf_reg_state *src_lo, *dst_lo;
+
+ dst_lo = &lo_reg0;
+ src_lo = &lo_reg1;
+ coerce_reg_to_size(dst_lo, 4);
+ coerce_reg_to_size(src_lo, 4);
+
if (dst_reg->type == SCALAR_VALUE &&
- regs[insn->src_reg].type == SCALAR_VALUE) {
- if (tnum_is_const(regs[insn->src_reg].var_off))
+ src_reg->type == SCALAR_VALUE) {
+ if (tnum_is_const(src_reg->var_off) ||
+ (is_jmp32 && tnum_is_const(src_lo->var_off)))
reg_set_min_max(&other_branch_regs[insn->dst_reg],
- dst_reg, regs[insn->src_reg].var_off.value,
- opcode);
- else if (tnum_is_const(dst_reg->var_off))
+ dst_reg,
+ is_jmp32
+ ? src_lo->var_off.value
+ : src_reg->var_off.value,
+ opcode, is_jmp32);
+ else if (tnum_is_const(dst_reg->var_off) ||
+ (is_jmp32 && tnum_is_const(dst_lo->var_off)))
reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
- ®s[insn->src_reg],
- dst_reg->var_off.value, opcode);
- else if (opcode == BPF_JEQ || opcode == BPF_JNE)
+ src_reg,
+ is_jmp32
+ ? dst_lo->var_off.value
+ : dst_reg->var_off.value,
+ opcode, is_jmp32);
+ else if (!is_jmp32 &&
+ (opcode == BPF_JEQ || opcode == BPF_JNE))
/* Comparing for equality, we can combine knowledge */
reg_combine_min_max(&other_branch_regs[insn->src_reg],
&other_branch_regs[insn->dst_reg],
- ®s[insn->src_reg],
- ®s[insn->dst_reg], opcode);
+ src_reg, dst_reg, opcode);
}
} else if (dst_reg->type == SCALAR_VALUE) {
reg_set_min_max(&other_branch_regs[insn->dst_reg],
- dst_reg, insn->imm, opcode);
+ dst_reg, insn->imm, opcode, is_jmp32);
}
- /* detect if R == 0 where R is returned from bpf_map_lookup_elem() */
- if (BPF_SRC(insn->code) == BPF_K &&
+ /* detect if R == 0 where R is returned from bpf_map_lookup_elem().
+ * NOTE: these optimizations below are related with pointer comparison
+ * which will never be JMP32.
+ */
+ if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
- dst_reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
- /* Mark all identical map registers in each branch as either
+ reg_type_may_be_null(dst_reg->type)) {
+ /* Mark all identical registers in each branch as either
* safe or unknown depending R == 0 or R != 0 conditional.
*/
- mark_map_regs(this_branch, insn->dst_reg, opcode == BPF_JNE);
- mark_map_regs(other_branch, insn->dst_reg, opcode == BPF_JEQ);
+ mark_ptr_or_null_regs(this_branch, insn->dst_reg,
+ opcode == BPF_JNE);
+ mark_ptr_or_null_regs(other_branch, insn->dst_reg,
+ opcode == BPF_JEQ);
} else if (!try_match_pkt_pointers(insn, dst_reg, ®s[insn->src_reg],
this_branch, other_branch) &&
is_pointer_value(env, insn->dst_reg)) {
@@ -3932,23 +5936,17 @@
insn->dst_reg);
return -EACCES;
}
- if (env->log.level)
+ if (env->log.level & BPF_LOG_LEVEL)
print_verifier_state(env, this_branch->frame[this_branch->curframe]);
return 0;
}
-/* return the map pointer stored inside BPF_LD_IMM64 instruction */
-static struct bpf_map *ld_imm64_to_map_ptr(struct bpf_insn *insn)
-{
- u64 imm64 = ((u64) (u32) insn[0].imm) | ((u64) (u32) insn[1].imm) << 32;
-
- return (struct bpf_map *) (unsigned long) imm64;
-}
-
/* verify BPF_LD_IMM64 instruction */
static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
{
+ struct bpf_insn_aux_data *aux = cur_aux(env);
struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_map *map;
int err;
if (BPF_SIZE(insn->code) != BPF_DW) {
@@ -3972,11 +5970,22 @@
return 0;
}
- /* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */
- BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD);
+ map = env->used_maps[aux->map_index];
+ mark_reg_known_zero(env, regs, insn->dst_reg);
+ regs[insn->dst_reg].map_ptr = map;
- regs[insn->dst_reg].type = CONST_PTR_TO_MAP;
- regs[insn->dst_reg].map_ptr = ld_imm64_to_map_ptr(insn);
+ if (insn->src_reg == BPF_PSEUDO_MAP_VALUE) {
+ regs[insn->dst_reg].type = PTR_TO_MAP_VALUE;
+ regs[insn->dst_reg].off = aux->map_off;
+ if (map_value_has_spin_lock(map))
+ regs[insn->dst_reg].id = ++env->id_gen;
+ } else if (insn->src_reg == BPF_PSEUDO_MAP_FD) {
+ regs[insn->dst_reg].type = CONST_PTR_TO_MAP;
+ } else {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
+
return 0;
}
@@ -4047,6 +6056,21 @@
if (err)
return err;
+ /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
+ * gen_ld_abs() may terminate the program at runtime, leading to
+ * reference leak.
+ */
+ err = check_reference_leak(env);
+ if (err) {
+ verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
+ return err;
+ }
+
+ if (env->cur_state->active_spin_lock) {
+ verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
+ return -EINVAL;
+ }
+
if (regs[BPF_REG_6].type != PTR_TO_CTX) {
verbose(env,
"at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
@@ -4071,20 +6095,34 @@
* Already marked as written above.
*/
mark_reg_unknown(env, regs, BPF_REG_0);
+ /* ld_abs load up to 32-bit skb data. */
+ regs[BPF_REG_0].subreg_def = env->insn_idx + 1;
return 0;
}
static int check_return_code(struct bpf_verifier_env *env)
{
+ struct tnum enforce_attach_type_range = tnum_unknown;
struct bpf_reg_state *reg;
struct tnum range = tnum_range(0, 1);
switch (env->prog->type) {
- case BPF_PROG_TYPE_CGROUP_SKB:
- case BPF_PROG_TYPE_CGROUP_SOCK:
case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+ if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
+ env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG)
+ range = tnum_range(1, 1);
+ break;
+ case BPF_PROG_TYPE_CGROUP_SKB:
+ if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) {
+ range = tnum_range(0, 3);
+ enforce_attach_type_range = tnum_range(2, 3);
+ }
+ break;
+ case BPF_PROG_TYPE_CGROUP_SOCK:
case BPF_PROG_TYPE_SOCK_OPS:
case BPF_PROG_TYPE_CGROUP_DEVICE:
+ case BPF_PROG_TYPE_CGROUP_SYSCTL:
+ case BPF_PROG_TYPE_CGROUP_SOCKOPT:
break;
default:
return 0;
@@ -4098,18 +6136,23 @@
}
if (!tnum_in(range, reg->var_off)) {
+ char tn_buf[48];
+
verbose(env, "At program exit the register R0 ");
if (!tnum_is_unknown(reg->var_off)) {
- char tn_buf[48];
-
tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
verbose(env, "has value %s", tn_buf);
} else {
verbose(env, "has unknown scalar value");
}
- verbose(env, " should have been 0 or 1\n");
+ tnum_strn(tn_buf, sizeof(tn_buf), range);
+ verbose(env, " should have been in %s\n", tn_buf);
return -EINVAL;
}
+
+ if (!tnum_is_unknown(enforce_attach_type_range) &&
+ tnum_in(enforce_attach_type_range, reg->var_off))
+ env->prog->enforce_expected_attach_type = 1;
return 0;
}
@@ -4153,19 +6196,37 @@
BRANCH = 2,
};
-#define STATE_LIST_MARK ((struct bpf_verifier_state_list *) -1L)
+static u32 state_htab_size(struct bpf_verifier_env *env)
+{
+ return env->prog->len;
+}
-static int *insn_stack; /* stack of insns to process */
-static int cur_stack; /* current stack index */
-static int *insn_state;
+static struct bpf_verifier_state_list **explored_state(
+ struct bpf_verifier_env *env,
+ int idx)
+{
+ struct bpf_verifier_state *cur = env->cur_state;
+ struct bpf_func_state *state = cur->frame[cur->curframe];
+
+ return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)];
+}
+
+static void init_explored_state(struct bpf_verifier_env *env, int idx)
+{
+ env->insn_aux_data[idx].prune_point = true;
+}
/* t, w, e - match pseudo-code above:
* t - index of current instruction
* w - next instruction
* e - edge
*/
-static int push_insn(int t, int w, int e, struct bpf_verifier_env *env)
+static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
+ bool loop_ok)
{
+ int *insn_stack = env->cfg.insn_stack;
+ int *insn_state = env->cfg.insn_state;
+
if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
return 0;
@@ -4173,23 +6234,28 @@
return 0;
if (w < 0 || w >= env->prog->len) {
+ verbose_linfo(env, t, "%d: ", t);
verbose(env, "jump out of range from insn %d to %d\n", t, w);
return -EINVAL;
}
if (e == BRANCH)
/* mark branch target for state pruning */
- env->explored_states[w] = STATE_LIST_MARK;
+ init_explored_state(env, w);
if (insn_state[w] == 0) {
/* tree-edge */
insn_state[t] = DISCOVERED | e;
insn_state[w] = DISCOVERED;
- if (cur_stack >= env->prog->len)
+ if (env->cfg.cur_stack >= env->prog->len)
return -E2BIG;
- insn_stack[cur_stack++] = w;
+ insn_stack[env->cfg.cur_stack++] = w;
return 1;
} else if ((insn_state[w] & 0xF0) == DISCOVERED) {
+ if (loop_ok && env->allow_ptr_leaks)
+ return 0;
+ verbose_linfo(env, t, "%d: ", t);
+ verbose_linfo(env, w, "%d: ", w);
verbose(env, "back-edge from insn %d to %d\n", t, w);
return -EINVAL;
} else if (insn_state[w] == EXPLORED) {
@@ -4209,48 +6275,47 @@
{
struct bpf_insn *insns = env->prog->insnsi;
int insn_cnt = env->prog->len;
+ int *insn_stack, *insn_state;
int ret = 0;
int i, t;
- ret = check_subprogs(env);
- if (ret < 0)
- return ret;
-
- insn_state = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+ insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
if (!insn_state)
return -ENOMEM;
- insn_stack = kcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+ insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
if (!insn_stack) {
- kfree(insn_state);
+ kvfree(insn_state);
return -ENOMEM;
}
insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */
insn_stack[0] = 0; /* 0 is the first instruction */
- cur_stack = 1;
+ env->cfg.cur_stack = 1;
peek_stack:
- if (cur_stack == 0)
+ if (env->cfg.cur_stack == 0)
goto check_state;
- t = insn_stack[cur_stack - 1];
+ t = insn_stack[env->cfg.cur_stack - 1];
- if (BPF_CLASS(insns[t].code) == BPF_JMP) {
+ if (BPF_CLASS(insns[t].code) == BPF_JMP ||
+ BPF_CLASS(insns[t].code) == BPF_JMP32) {
u8 opcode = BPF_OP(insns[t].code);
if (opcode == BPF_EXIT) {
goto mark_explored;
} else if (opcode == BPF_CALL) {
- ret = push_insn(t, t + 1, FALLTHROUGH, env);
+ ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
if (ret == 1)
goto peek_stack;
else if (ret < 0)
goto err_free;
if (t + 1 < insn_cnt)
- env->explored_states[t + 1] = STATE_LIST_MARK;
+ init_explored_state(env, t + 1);
if (insns[t].src_reg == BPF_PSEUDO_CALL) {
- env->explored_states[t] = STATE_LIST_MARK;
- ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env);
+ init_explored_state(env, t);
+ ret = push_insn(t, t + insns[t].imm + 1, BRANCH,
+ env, false);
if (ret == 1)
goto peek_stack;
else if (ret < 0)
@@ -4263,26 +6328,31 @@
}
/* unconditional jump with single edge */
ret = push_insn(t, t + insns[t].off + 1,
- FALLTHROUGH, env);
+ FALLTHROUGH, env, true);
if (ret == 1)
goto peek_stack;
else if (ret < 0)
goto err_free;
+ /* unconditional jmp is not a good pruning point,
+ * but it's marked, since backtracking needs
+ * to record jmp history in is_state_visited().
+ */
+ init_explored_state(env, t + insns[t].off + 1);
/* tell verifier to check for equivalent states
* after every call and jump
*/
if (t + 1 < insn_cnt)
- env->explored_states[t + 1] = STATE_LIST_MARK;
+ init_explored_state(env, t + 1);
} else {
/* conditional jump with two edges */
- env->explored_states[t] = STATE_LIST_MARK;
- ret = push_insn(t, t + 1, FALLTHROUGH, env);
+ init_explored_state(env, t);
+ ret = push_insn(t, t + 1, FALLTHROUGH, env, true);
if (ret == 1)
goto peek_stack;
else if (ret < 0)
goto err_free;
- ret = push_insn(t, t + insns[t].off + 1, BRANCH, env);
+ ret = push_insn(t, t + insns[t].off + 1, BRANCH, env, true);
if (ret == 1)
goto peek_stack;
else if (ret < 0)
@@ -4292,7 +6362,7 @@
/* all other non-branch instructions with single
* fall-through edge
*/
- ret = push_insn(t, t + 1, FALLTHROUGH, env);
+ ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
if (ret == 1)
goto peek_stack;
else if (ret < 0)
@@ -4301,7 +6371,7 @@
mark_explored:
insn_state[t] = EXPLORED;
- if (cur_stack-- <= 0) {
+ if (env->cfg.cur_stack-- <= 0) {
verbose(env, "pop stack internal bug\n");
ret = -EFAULT;
goto err_free;
@@ -4319,11 +6389,284 @@
ret = 0; /* cfg looks good */
err_free:
- kfree(insn_state);
- kfree(insn_stack);
+ kvfree(insn_state);
+ kvfree(insn_stack);
+ env->cfg.insn_state = env->cfg.insn_stack = NULL;
return ret;
}
+/* The minimum supported BTF func info size */
+#define MIN_BPF_FUNCINFO_SIZE 8
+#define MAX_FUNCINFO_REC_SIZE 252
+
+static int check_btf_func(struct bpf_verifier_env *env,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ u32 i, nfuncs, urec_size, min_size;
+ u32 krec_size = sizeof(struct bpf_func_info);
+ struct bpf_func_info *krecord;
+ const struct btf_type *type;
+ struct bpf_prog *prog;
+ const struct btf *btf;
+ void __user *urecord;
+ u32 prev_offset = 0;
+ int ret = 0;
+
+ nfuncs = attr->func_info_cnt;
+ if (!nfuncs)
+ return 0;
+
+ if (nfuncs != env->subprog_cnt) {
+ verbose(env, "number of funcs in func_info doesn't match number of subprogs\n");
+ return -EINVAL;
+ }
+
+ urec_size = attr->func_info_rec_size;
+ if (urec_size < MIN_BPF_FUNCINFO_SIZE ||
+ urec_size > MAX_FUNCINFO_REC_SIZE ||
+ urec_size % sizeof(u32)) {
+ verbose(env, "invalid func info rec size %u\n", urec_size);
+ return -EINVAL;
+ }
+
+ prog = env->prog;
+ btf = prog->aux->btf;
+
+ urecord = u64_to_user_ptr(attr->func_info);
+ min_size = min_t(u32, krec_size, urec_size);
+
+ krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN);
+ if (!krecord)
+ return -ENOMEM;
+
+ for (i = 0; i < nfuncs; i++) {
+ ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size);
+ if (ret) {
+ if (ret == -E2BIG) {
+ verbose(env, "nonzero tailing record in func info");
+ /* set the size kernel expects so loader can zero
+ * out the rest of the record.
+ */
+ if (put_user(min_size, &uattr->func_info_rec_size))
+ ret = -EFAULT;
+ }
+ goto err_free;
+ }
+
+ if (copy_from_user(&krecord[i], urecord, min_size)) {
+ ret = -EFAULT;
+ goto err_free;
+ }
+
+ /* check insn_off */
+ if (i == 0) {
+ if (krecord[i].insn_off) {
+ verbose(env,
+ "nonzero insn_off %u for the first func info record",
+ krecord[i].insn_off);
+ ret = -EINVAL;
+ goto err_free;
+ }
+ } else if (krecord[i].insn_off <= prev_offset) {
+ verbose(env,
+ "same or smaller insn offset (%u) than previous func info record (%u)",
+ krecord[i].insn_off, prev_offset);
+ ret = -EINVAL;
+ goto err_free;
+ }
+
+ if (env->subprog_info[i].start != krecord[i].insn_off) {
+ verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
+ ret = -EINVAL;
+ goto err_free;
+ }
+
+ /* check type_id */
+ type = btf_type_by_id(btf, krecord[i].type_id);
+ if (!type || BTF_INFO_KIND(type->info) != BTF_KIND_FUNC) {
+ verbose(env, "invalid type id %d in func info",
+ krecord[i].type_id);
+ ret = -EINVAL;
+ goto err_free;
+ }
+
+ prev_offset = krecord[i].insn_off;
+ urecord += urec_size;
+ }
+
+ prog->aux->func_info = krecord;
+ prog->aux->func_info_cnt = nfuncs;
+ return 0;
+
+err_free:
+ kvfree(krecord);
+ return ret;
+}
+
+static void adjust_btf_func(struct bpf_verifier_env *env)
+{
+ int i;
+
+ if (!env->prog->aux->func_info)
+ return;
+
+ for (i = 0; i < env->subprog_cnt; i++)
+ env->prog->aux->func_info[i].insn_off = env->subprog_info[i].start;
+}
+
+#define MIN_BPF_LINEINFO_SIZE (offsetof(struct bpf_line_info, line_col) + \
+ sizeof(((struct bpf_line_info *)(0))->line_col))
+#define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE
+
+static int check_btf_line(struct bpf_verifier_env *env,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0;
+ struct bpf_subprog_info *sub;
+ struct bpf_line_info *linfo;
+ struct bpf_prog *prog;
+ const struct btf *btf;
+ void __user *ulinfo;
+ int err;
+
+ nr_linfo = attr->line_info_cnt;
+ if (!nr_linfo)
+ return 0;
+
+ rec_size = attr->line_info_rec_size;
+ if (rec_size < MIN_BPF_LINEINFO_SIZE ||
+ rec_size > MAX_LINEINFO_REC_SIZE ||
+ rec_size & (sizeof(u32) - 1))
+ return -EINVAL;
+
+ /* Need to zero it in case the userspace may
+ * pass in a smaller bpf_line_info object.
+ */
+ linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!linfo)
+ return -ENOMEM;
+
+ prog = env->prog;
+ btf = prog->aux->btf;
+
+ s = 0;
+ sub = env->subprog_info;
+ ulinfo = u64_to_user_ptr(attr->line_info);
+ expected_size = sizeof(struct bpf_line_info);
+ ncopy = min_t(u32, expected_size, rec_size);
+ for (i = 0; i < nr_linfo; i++) {
+ err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size);
+ if (err) {
+ if (err == -E2BIG) {
+ verbose(env, "nonzero tailing record in line_info");
+ if (put_user(expected_size,
+ &uattr->line_info_rec_size))
+ err = -EFAULT;
+ }
+ goto err_free;
+ }
+
+ if (copy_from_user(&linfo[i], ulinfo, ncopy)) {
+ err = -EFAULT;
+ goto err_free;
+ }
+
+ /*
+ * Check insn_off to ensure
+ * 1) strictly increasing AND
+ * 2) bounded by prog->len
+ *
+ * The linfo[0].insn_off == 0 check logically falls into
+ * the later "missing bpf_line_info for func..." case
+ * because the first linfo[0].insn_off must be the
+ * first sub also and the first sub must have
+ * subprog_info[0].start == 0.
+ */
+ if ((i && linfo[i].insn_off <= prev_offset) ||
+ linfo[i].insn_off >= prog->len) {
+ verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
+ i, linfo[i].insn_off, prev_offset,
+ prog->len);
+ err = -EINVAL;
+ goto err_free;
+ }
+
+ if (!prog->insnsi[linfo[i].insn_off].code) {
+ verbose(env,
+ "Invalid insn code at line_info[%u].insn_off\n",
+ i);
+ err = -EINVAL;
+ goto err_free;
+ }
+
+ if (!btf_name_by_offset(btf, linfo[i].line_off) ||
+ !btf_name_by_offset(btf, linfo[i].file_name_off)) {
+ verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i);
+ err = -EINVAL;
+ goto err_free;
+ }
+
+ if (s != env->subprog_cnt) {
+ if (linfo[i].insn_off == sub[s].start) {
+ sub[s].linfo_idx = i;
+ s++;
+ } else if (sub[s].start < linfo[i].insn_off) {
+ verbose(env, "missing bpf_line_info for func#%u\n", s);
+ err = -EINVAL;
+ goto err_free;
+ }
+ }
+
+ prev_offset = linfo[i].insn_off;
+ ulinfo += rec_size;
+ }
+
+ if (s != env->subprog_cnt) {
+ verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n",
+ env->subprog_cnt - s, s);
+ err = -EINVAL;
+ goto err_free;
+ }
+
+ prog->aux->linfo = linfo;
+ prog->aux->nr_linfo = nr_linfo;
+
+ return 0;
+
+err_free:
+ kvfree(linfo);
+ return err;
+}
+
+static int check_btf_info(struct bpf_verifier_env *env,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ struct btf *btf;
+ int err;
+
+ if (!attr->func_info_cnt && !attr->line_info_cnt)
+ return 0;
+
+ btf = btf_get_by_fd(attr->prog_btf_fd);
+ if (IS_ERR(btf))
+ return PTR_ERR(btf);
+ env->prog->aux->btf = btf;
+
+ err = check_btf_func(env, attr, uattr);
+ if (err)
+ return err;
+
+ err = check_btf_line(env, attr, uattr);
+ if (err)
+ return err;
+
+ return 0;
+}
+
/* check %cur's range satisfies %old's */
static bool range_within(struct bpf_reg_state *old,
struct bpf_reg_state *cur)
@@ -4370,6 +6713,102 @@
return false;
}
+static void clean_func_state(struct bpf_verifier_env *env,
+ struct bpf_func_state *st)
+{
+ enum bpf_reg_liveness live;
+ int i, j;
+
+ for (i = 0; i < BPF_REG_FP; i++) {
+ live = st->regs[i].live;
+ /* liveness must not touch this register anymore */
+ st->regs[i].live |= REG_LIVE_DONE;
+ if (!(live & REG_LIVE_READ))
+ /* since the register is unused, clear its state
+ * to make further comparison simpler
+ */
+ __mark_reg_not_init(&st->regs[i]);
+ }
+
+ for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) {
+ live = st->stack[i].spilled_ptr.live;
+ /* liveness must not touch this stack slot anymore */
+ st->stack[i].spilled_ptr.live |= REG_LIVE_DONE;
+ if (!(live & REG_LIVE_READ)) {
+ __mark_reg_not_init(&st->stack[i].spilled_ptr);
+ for (j = 0; j < BPF_REG_SIZE; j++)
+ st->stack[i].slot_type[j] = STACK_INVALID;
+ }
+ }
+}
+
+static void clean_verifier_state(struct bpf_verifier_env *env,
+ struct bpf_verifier_state *st)
+{
+ int i;
+
+ if (st->frame[0]->regs[0].live & REG_LIVE_DONE)
+ /* all regs in this state in all frames were already marked */
+ return;
+
+ for (i = 0; i <= st->curframe; i++)
+ clean_func_state(env, st->frame[i]);
+}
+
+/* the parentage chains form a tree.
+ * the verifier states are added to state lists at given insn and
+ * pushed into state stack for future exploration.
+ * when the verifier reaches bpf_exit insn some of the verifer states
+ * stored in the state lists have their final liveness state already,
+ * but a lot of states will get revised from liveness point of view when
+ * the verifier explores other branches.
+ * Example:
+ * 1: r0 = 1
+ * 2: if r1 == 100 goto pc+1
+ * 3: r0 = 2
+ * 4: exit
+ * when the verifier reaches exit insn the register r0 in the state list of
+ * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
+ * of insn 2 and goes exploring further. At the insn 4 it will walk the
+ * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
+ *
+ * Since the verifier pushes the branch states as it sees them while exploring
+ * the program the condition of walking the branch instruction for the second
+ * time means that all states below this branch were already explored and
+ * their final liveness markes are already propagated.
+ * Hence when the verifier completes the search of state list in is_state_visited()
+ * we can call this clean_live_states() function to mark all liveness states
+ * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
+ * will not be used.
+ * This function also clears the registers and stack for states that !READ
+ * to simplify state merging.
+ *
+ * Important note here that walking the same branch instruction in the callee
+ * doesn't meant that the states are DONE. The verifier has to compare
+ * the callsites
+ */
+static void clean_live_states(struct bpf_verifier_env *env, int insn,
+ struct bpf_verifier_state *cur)
+{
+ struct bpf_verifier_state_list *sl;
+ int i;
+
+ sl = *explored_state(env, insn);
+ while (sl) {
+ if (sl->state.branches)
+ goto next;
+ if (sl->state.insn_idx != insn ||
+ sl->state.curframe != cur->curframe)
+ goto next;
+ for (i = 0; i <= cur->curframe; i++)
+ if (sl->state.frame[i]->callsite != cur->frame[i]->callsite)
+ goto next;
+ clean_verifier_state(env, &sl->state);
+next:
+ sl = sl->next;
+ }
+}
+
/* Returns true if (rold safe implies rcur safe) */
static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur,
struct idpair *idmap)
@@ -4380,7 +6819,7 @@
/* explored state didn't use this */
return true;
- equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, frameno)) == 0;
+ equal = memcmp(rold, rcur, offsetof(struct bpf_reg_state, parent)) == 0;
if (rold->type == PTR_TO_STACK)
/* two stack pointers are equal only if they're pointing to
@@ -4399,6 +6838,8 @@
switch (rold->type) {
case SCALAR_VALUE:
if (rcur->type == SCALAR_VALUE) {
+ if (!rold->precise && !rcur->precise)
+ return true;
/* new val must satisfy old val knowledge */
return range_within(rold, rcur) &&
tnum_in(rold->var_off, rcur->var_off);
@@ -4415,8 +6856,11 @@
case PTR_TO_MAP_VALUE:
/* If the new min/max/var_off satisfy the old ones and
* everything else matches, we are OK.
- * We don't care about the 'id' value, because nothing
- * uses it for PTR_TO_MAP_VALUE (only for ..._OR_NULL)
+ * 'id' is not compared, since it's only used for maps with
+ * bpf_spin_lock inside map element and in such cases if
+ * the rest of the prog is valid for one map element then
+ * it's valid for all map elements regardless of the key
+ * used in bpf_map_lookup()
*/
return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
range_within(rold, rcur) &&
@@ -4461,6 +6905,14 @@
case PTR_TO_CTX:
case CONST_PTR_TO_MAP:
case PTR_TO_PACKET_END:
+ case PTR_TO_FLOW_KEYS:
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCKET_OR_NULL:
+ case PTR_TO_SOCK_COMMON:
+ case PTR_TO_SOCK_COMMON_OR_NULL:
+ case PTR_TO_TCP_SOCK:
+ case PTR_TO_TCP_SOCK_OR_NULL:
+ case PTR_TO_XDP_SOCK:
/* Only valid matches are exact, which memcmp() above
* would have accepted
*/
@@ -4480,12 +6932,6 @@
{
int i, spi;
- /* if explored stack has more populated slots than current stack
- * such stacks are not equivalent
- */
- if (old->allocated_stack > cur->allocated_stack)
- return false;
-
/* walk slots of the explored stack and ignore any additional
* slots in the current stack, since explored(safe) state
* didn't use them
@@ -4493,12 +6939,21 @@
for (i = 0; i < old->allocated_stack; i++) {
spi = i / BPF_REG_SIZE;
- if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ))
+ if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) {
+ i += BPF_REG_SIZE - 1;
/* explored state didn't use this */
continue;
+ }
if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID)
continue;
+
+ /* explored stack has more populated slots than current stack
+ * and these slots were used
+ */
+ if (i >= cur->allocated_stack)
+ return false;
+
/* if old state was safe with misc data in the stack
* it will be safe with zero-initialized stack.
* The opposite is not true
@@ -4536,6 +6991,14 @@
return true;
}
+static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur)
+{
+ if (old->acquired_refs != cur->acquired_refs)
+ return false;
+ return !memcmp(old->refs, cur->refs,
+ sizeof(*old->refs) * old->acquired_refs);
+}
+
/* compare two verifier states
*
* all states stored in state_list are known to be valid, since
@@ -4581,6 +7044,9 @@
if (!stacksafe(old, cur, idmap))
goto out_free;
+
+ if (!refsafe(old, cur))
+ goto out_free;
ret = true;
out_free:
kfree(idmap);
@@ -4596,6 +7062,15 @@
if (old->curframe != cur->curframe)
return false;
+ /* Verification state from speculative execution simulation
+ * must never prune a non-speculative execution one.
+ */
+ if (old->speculative && !cur->speculative)
+ return false;
+
+ if (old->active_spin_lock != cur->active_spin_lock)
+ return false;
+
/* for states to be equal callsites have to be the same
* and all frame states need to be equivalent
*/
@@ -4608,19 +7083,49 @@
return true;
}
+/* Return 0 if no propagation happened. Return negative error code if error
+ * happened. Otherwise, return the propagated bit.
+ */
+static int propagate_liveness_reg(struct bpf_verifier_env *env,
+ struct bpf_reg_state *reg,
+ struct bpf_reg_state *parent_reg)
+{
+ u8 parent_flag = parent_reg->live & REG_LIVE_READ;
+ u8 flag = reg->live & REG_LIVE_READ;
+ int err;
+
+ /* When comes here, read flags of PARENT_REG or REG could be any of
+ * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
+ * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
+ */
+ if (parent_flag == REG_LIVE_READ64 ||
+ /* Or if there is no read flag from REG. */
+ !flag ||
+ /* Or if the read flag from REG is the same as PARENT_REG. */
+ parent_flag == flag)
+ return 0;
+
+ err = mark_reg_read(env, reg, parent_reg, flag);
+ if (err)
+ return err;
+
+ return flag;
+}
+
/* A write screens off any subsequent reads; but write marks come from the
* straight-line code between a state and its parent. When we arrive at an
* equivalent state (jump target or such) we didn't arrive by the straight-line
* code, so read marks in the state must propagate to the parent regardless
* of the state's write marks. That's what 'parent == state->parent' comparison
- * in mark_reg_read() and mark_stack_slot_read() is for.
+ * in mark_reg_read() is for.
*/
static int propagate_liveness(struct bpf_verifier_env *env,
const struct bpf_verifier_state *vstate,
struct bpf_verifier_state *vparent)
{
- int i, frame, err = 0;
+ struct bpf_reg_state *state_reg, *parent_reg;
struct bpf_func_state *state, *parent;
+ int i, frame, err = 0;
if (vparent->curframe != vstate->curframe) {
WARN(1, "propagate_live: parent frame %d current frame %d\n",
@@ -4629,48 +7134,156 @@
}
/* Propagate read liveness of registers... */
BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
- /* We don't need to worry about FP liveness because it's read-only */
- for (i = 0; i < BPF_REG_FP; i++) {
- if (vparent->frame[vparent->curframe]->regs[i].live & REG_LIVE_READ)
- continue;
- if (vstate->frame[vstate->curframe]->regs[i].live & REG_LIVE_READ) {
- err = mark_reg_read(env, vstate, vparent, i);
- if (err)
+ for (frame = 0; frame <= vstate->curframe; frame++) {
+ parent = vparent->frame[frame];
+ state = vstate->frame[frame];
+ parent_reg = parent->regs;
+ state_reg = state->regs;
+ /* We don't need to worry about FP liveness, it's read-only */
+ for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {
+ err = propagate_liveness_reg(env, &state_reg[i],
+ &parent_reg[i]);
+ if (err < 0)
+ return err;
+ if (err == REG_LIVE_READ64)
+ mark_insn_zext(env, &parent_reg[i]);
+ }
+
+ /* Propagate stack slots. */
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
+ i < parent->allocated_stack / BPF_REG_SIZE; i++) {
+ parent_reg = &parent->stack[i].spilled_ptr;
+ state_reg = &state->stack[i].spilled_ptr;
+ err = propagate_liveness_reg(env, state_reg,
+ parent_reg);
+ if (err < 0)
return err;
}
}
-
- /* ... and stack slots */
- for (frame = 0; frame <= vstate->curframe; frame++) {
- state = vstate->frame[frame];
- parent = vparent->frame[frame];
- for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
- i < parent->allocated_stack / BPF_REG_SIZE; i++) {
- if (parent->stack[i].spilled_ptr.live & REG_LIVE_READ)
- continue;
- if (state->stack[i].spilled_ptr.live & REG_LIVE_READ)
- mark_stack_slot_read(env, vstate, vparent, i, frame);
- }
- }
- return err;
+ return 0;
}
+/* find precise scalars in the previous equivalent state and
+ * propagate them into the current state
+ */
+static int propagate_precision(struct bpf_verifier_env *env,
+ const struct bpf_verifier_state *old)
+{
+ struct bpf_reg_state *state_reg;
+ struct bpf_func_state *state;
+ int i, err = 0;
+
+ state = old->frame[old->curframe];
+ state_reg = state->regs;
+ for (i = 0; i < BPF_REG_FP; i++, state_reg++) {
+ if (state_reg->type != SCALAR_VALUE ||
+ !state_reg->precise)
+ continue;
+ if (env->log.level & BPF_LOG_LEVEL2)
+ verbose(env, "propagating r%d\n", i);
+ err = mark_chain_precision(env, i);
+ if (err < 0)
+ return err;
+ }
+
+ for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+ if (state->stack[i].slot_type[0] != STACK_SPILL)
+ continue;
+ state_reg = &state->stack[i].spilled_ptr;
+ if (state_reg->type != SCALAR_VALUE ||
+ !state_reg->precise)
+ continue;
+ if (env->log.level & BPF_LOG_LEVEL2)
+ verbose(env, "propagating fp%d\n",
+ (-i - 1) * BPF_REG_SIZE);
+ err = mark_chain_precision_stack(env, i);
+ if (err < 0)
+ return err;
+ }
+ return 0;
+}
+
+static bool states_maybe_looping(struct bpf_verifier_state *old,
+ struct bpf_verifier_state *cur)
+{
+ struct bpf_func_state *fold, *fcur;
+ int i, fr = cur->curframe;
+
+ if (old->curframe != fr)
+ return false;
+
+ fold = old->frame[fr];
+ fcur = cur->frame[fr];
+ for (i = 0; i < MAX_BPF_REG; i++)
+ if (memcmp(&fold->regs[i], &fcur->regs[i],
+ offsetof(struct bpf_reg_state, parent)))
+ return false;
+ return true;
+}
+
+
static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
{
struct bpf_verifier_state_list *new_sl;
- struct bpf_verifier_state_list *sl;
- struct bpf_verifier_state *cur = env->cur_state;
- int i, j, err;
+ struct bpf_verifier_state_list *sl, **pprev;
+ struct bpf_verifier_state *cur = env->cur_state, *new;
+ int i, j, err, states_cnt = 0;
+ bool add_new_state = env->test_state_freq ? true : false;
- sl = env->explored_states[insn_idx];
- if (!sl)
+ cur->last_insn_idx = env->prev_insn_idx;
+ if (!env->insn_aux_data[insn_idx].prune_point)
/* this 'insn_idx' instruction wasn't marked, so we will not
* be doing state search here
*/
return 0;
- while (sl != STATE_LIST_MARK) {
+ /* bpf progs typically have pruning point every 4 instructions
+ * http://vger.kernel.org/bpfconf2019.html#session-1
+ * Do not add new state for future pruning if the verifier hasn't seen
+ * at least 2 jumps and at least 8 instructions.
+ * This heuristics helps decrease 'total_states' and 'peak_states' metric.
+ * In tests that amounts to up to 50% reduction into total verifier
+ * memory consumption and 20% verifier time speedup.
+ */
+ if (env->jmps_processed - env->prev_jmps_processed >= 2 &&
+ env->insn_processed - env->prev_insn_processed >= 8)
+ add_new_state = true;
+
+ pprev = explored_state(env, insn_idx);
+ sl = *pprev;
+
+ clean_live_states(env, insn_idx, cur);
+
+ while (sl) {
+ states_cnt++;
+ if (sl->state.insn_idx != insn_idx)
+ goto next;
+ if (sl->state.branches) {
+ if (states_maybe_looping(&sl->state, cur) &&
+ states_equal(env, &sl->state, cur)) {
+ verbose_linfo(env, insn_idx, "; ");
+ verbose(env, "infinite loop detected at insn %d\n", insn_idx);
+ return -EINVAL;
+ }
+ /* if the verifier is processing a loop, avoid adding new state
+ * too often, since different loop iterations have distinct
+ * states and may not help future pruning.
+ * This threshold shouldn't be too low to make sure that
+ * a loop with large bound will be rejected quickly.
+ * The most abusive loop will be:
+ * r1 += 1
+ * if r1 < 1000000 goto pc-2
+ * 1M insn_procssed limit / 100 == 10k peak states.
+ * This threshold shouldn't be too high either, since states
+ * at the end of the loop are likely to be useful in pruning.
+ */
+ if (env->jmps_processed - env->prev_jmps_processed < 20 &&
+ env->insn_processed - env->prev_insn_processed < 100)
+ add_new_state = false;
+ goto miss;
+ }
if (states_equal(env, &sl->state, cur)) {
+ sl->hit_cnt++;
/* reached equivalent register/stack state,
* prune the search.
* Registers read by the continuation are read by us.
@@ -4682,69 +7295,192 @@
* this state and will pop a new one.
*/
err = propagate_liveness(env, &sl->state, cur);
+
+ /* if previous state reached the exit with precision and
+ * current state is equivalent to it (except precsion marks)
+ * the precision needs to be propagated back in
+ * the current state.
+ */
+ err = err ? : push_jmp_history(env, cur);
+ err = err ? : propagate_precision(env, &sl->state);
if (err)
return err;
return 1;
}
- sl = sl->next;
+miss:
+ /* when new state is not going to be added do not increase miss count.
+ * Otherwise several loop iterations will remove the state
+ * recorded earlier. The goal of these heuristics is to have
+ * states from some iterations of the loop (some in the beginning
+ * and some at the end) to help pruning.
+ */
+ if (add_new_state)
+ sl->miss_cnt++;
+ /* heuristic to determine whether this state is beneficial
+ * to keep checking from state equivalence point of view.
+ * Higher numbers increase max_states_per_insn and verification time,
+ * but do not meaningfully decrease insn_processed.
+ */
+ if (sl->miss_cnt > sl->hit_cnt * 3 + 3) {
+ /* the state is unlikely to be useful. Remove it to
+ * speed up verification
+ */
+ *pprev = sl->next;
+ if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) {
+ u32 br = sl->state.branches;
+
+ WARN_ONCE(br,
+ "BUG live_done but branches_to_explore %d\n",
+ br);
+ free_verifier_state(&sl->state, false);
+ kfree(sl);
+ env->peak_states--;
+ } else {
+ /* cannot free this state, since parentage chain may
+ * walk it later. Add it for free_list instead to
+ * be freed at the end of verification
+ */
+ sl->next = env->free_list;
+ env->free_list = sl;
+ }
+ sl = *pprev;
+ continue;
+ }
+next:
+ pprev = &sl->next;
+ sl = *pprev;
}
- /* there were no equivalent states, remember current one.
- * technically the current state is not proven to be safe yet,
+ if (env->max_states_per_insn < states_cnt)
+ env->max_states_per_insn = states_cnt;
+
+ if (!env->allow_ptr_leaks && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
+ return push_jmp_history(env, cur);
+
+ if (!add_new_state)
+ return push_jmp_history(env, cur);
+
+ /* There were no equivalent states, remember the current one.
+ * Technically the current state is not proven to be safe yet,
* but it will either reach outer most bpf_exit (which means it's safe)
- * or it will be rejected. Since there are no loops, we won't be
+ * or it will be rejected. When there are no loops the verifier won't be
* seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
- * again on the way to bpf_exit
+ * again on the way to bpf_exit.
+ * When looping the sl->state.branches will be > 0 and this state
+ * will not be considered for equivalence until branches == 0.
*/
new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
if (!new_sl)
return -ENOMEM;
+ env->total_states++;
+ env->peak_states++;
+ env->prev_jmps_processed = env->jmps_processed;
+ env->prev_insn_processed = env->insn_processed;
/* add new state to the head of linked list */
- err = copy_verifier_state(&new_sl->state, cur);
+ new = &new_sl->state;
+ err = copy_verifier_state(new, cur);
if (err) {
- free_verifier_state(&new_sl->state, false);
+ free_verifier_state(new, false);
kfree(new_sl);
return err;
}
- new_sl->next = env->explored_states[insn_idx];
- env->explored_states[insn_idx] = new_sl;
- /* connect new state to parentage chain */
- cur->parent = &new_sl->state;
+ new->insn_idx = insn_idx;
+ WARN_ONCE(new->branches != 1,
+ "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx);
+
+ cur->parent = new;
+ cur->first_insn_idx = insn_idx;
+ clear_jmp_history(cur);
+ new_sl->next = *explored_state(env, insn_idx);
+ *explored_state(env, insn_idx) = new_sl;
+ /* connect new state to parentage chain. Current frame needs all
+ * registers connected. Only r6 - r9 of the callers are alive (pushed
+ * to the stack implicitly by JITs) so in callers' frames connect just
+ * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
+ * the state of the call instruction (with WRITTEN set), and r0 comes
+ * from callee with its full parentage chain, anyway.
+ */
/* clear write marks in current state: the writes we did are not writes
* our child did, so they don't screen off its reads from us.
* (There are no read marks in current state, because reads always mark
* their parent and current state never has children yet. Only
* explored_states can get read marks.)
*/
- for (i = 0; i < BPF_REG_FP; i++)
- cur->frame[cur->curframe]->regs[i].live = REG_LIVE_NONE;
+ for (j = 0; j <= cur->curframe; j++) {
+ for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++)
+ cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i];
+ for (i = 0; i < BPF_REG_FP; i++)
+ cur->frame[j]->regs[i].live = REG_LIVE_NONE;
+ }
/* all stack frames are accessible from callee, clear them all */
for (j = 0; j <= cur->curframe; j++) {
struct bpf_func_state *frame = cur->frame[j];
+ struct bpf_func_state *newframe = new->frame[j];
- for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++)
+ for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) {
frame->stack[i].spilled_ptr.live = REG_LIVE_NONE;
+ frame->stack[i].spilled_ptr.parent =
+ &newframe->stack[i].spilled_ptr;
+ }
}
return 0;
}
+/* Return true if it's OK to have the same insn return a different type. */
+static bool reg_type_mismatch_ok(enum bpf_reg_type type)
+{
+ switch (type) {
+ case PTR_TO_CTX:
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCKET_OR_NULL:
+ case PTR_TO_SOCK_COMMON:
+ case PTR_TO_SOCK_COMMON_OR_NULL:
+ case PTR_TO_TCP_SOCK:
+ case PTR_TO_TCP_SOCK_OR_NULL:
+ case PTR_TO_XDP_SOCK:
+ return false;
+ default:
+ return true;
+ }
+}
+
+/* If an instruction was previously used with particular pointer types, then we
+ * need to be careful to avoid cases such as the below, where it may be ok
+ * for one branch accessing the pointer, but not ok for the other branch:
+ *
+ * R1 = sock_ptr
+ * goto X;
+ * ...
+ * R1 = some_other_valid_ptr;
+ * goto X;
+ * ...
+ * R2 = *(u32 *)(R1 + 0);
+ */
+static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev)
+{
+ return src != prev && (!reg_type_mismatch_ok(src) ||
+ !reg_type_mismatch_ok(prev));
+}
+
static int do_check(struct bpf_verifier_env *env)
{
struct bpf_verifier_state *state;
struct bpf_insn *insns = env->prog->insnsi;
struct bpf_reg_state *regs;
- int insn_cnt = env->prog->len, i;
- int insn_idx, prev_insn_idx = 0;
- int insn_processed = 0;
+ int insn_cnt = env->prog->len;
bool do_print_state = false;
+ int prev_insn_idx = -1;
+
+ env->prev_linfo = NULL;
state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL);
if (!state)
return -ENOMEM;
state->curframe = 0;
- state->parent = NULL;
+ state->speculative = false;
+ state->branches = 1;
state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL);
if (!state->frame[0]) {
kfree(state);
@@ -4755,39 +7491,42 @@
BPF_MAIN_FUNC /* callsite */,
0 /* frameno */,
0 /* subprogno, zero == main subprog */);
- insn_idx = 0;
+
for (;;) {
struct bpf_insn *insn;
u8 class;
int err;
- if (insn_idx >= insn_cnt) {
+ env->prev_insn_idx = prev_insn_idx;
+ if (env->insn_idx >= insn_cnt) {
verbose(env, "invalid insn idx %d insn_cnt %d\n",
- insn_idx, insn_cnt);
+ env->insn_idx, insn_cnt);
return -EFAULT;
}
- insn = &insns[insn_idx];
+ insn = &insns[env->insn_idx];
class = BPF_CLASS(insn->code);
- if (++insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
+ if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
verbose(env,
"BPF program is too large. Processed %d insn\n",
- insn_processed);
+ env->insn_processed);
return -E2BIG;
}
- err = is_state_visited(env, insn_idx);
+ err = is_state_visited(env, env->insn_idx);
if (err < 0)
return err;
if (err == 1) {
/* found equivalent state, can prune the search */
- if (env->log.level) {
+ if (env->log.level & BPF_LOG_LEVEL) {
if (do_print_state)
- verbose(env, "\nfrom %d to %d: safe\n",
- prev_insn_idx, insn_idx);
+ verbose(env, "\nfrom %d to %d%s: safe\n",
+ env->prev_insn_idx, env->insn_idx,
+ env->cur_state->speculative ?
+ " (speculative execution)" : "");
else
- verbose(env, "%d: safe\n", insn_idx);
+ verbose(env, "%d: safe\n", env->insn_idx);
}
goto process_bpf_exit;
}
@@ -4798,35 +7537,41 @@
if (need_resched())
cond_resched();
- if (env->log.level > 1 || (env->log.level && do_print_state)) {
- if (env->log.level > 1)
- verbose(env, "%d:", insn_idx);
+ if (env->log.level & BPF_LOG_LEVEL2 ||
+ (env->log.level & BPF_LOG_LEVEL && do_print_state)) {
+ if (env->log.level & BPF_LOG_LEVEL2)
+ verbose(env, "%d:", env->insn_idx);
else
- verbose(env, "\nfrom %d to %d:",
- prev_insn_idx, insn_idx);
+ verbose(env, "\nfrom %d to %d%s:",
+ env->prev_insn_idx, env->insn_idx,
+ env->cur_state->speculative ?
+ " (speculative execution)" : "");
print_verifier_state(env, state->frame[state->curframe]);
do_print_state = false;
}
- if (env->log.level) {
+ if (env->log.level & BPF_LOG_LEVEL) {
const struct bpf_insn_cbs cbs = {
.cb_print = verbose,
.private_data = env,
};
- verbose(env, "%d: ", insn_idx);
+ verbose_linfo(env, env->insn_idx, "; ");
+ verbose(env, "%d: ", env->insn_idx);
print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
}
if (bpf_prog_is_dev_bound(env->prog->aux)) {
- err = bpf_prog_offload_verify_insn(env, insn_idx,
- prev_insn_idx);
+ err = bpf_prog_offload_verify_insn(env, env->insn_idx,
+ env->prev_insn_idx);
if (err)
return err;
}
regs = cur_regs(env);
- env->insn_aux_data[insn_idx].seen = true;
+ env->insn_aux_data[env->insn_idx].seen = true;
+ prev_insn_idx = env->insn_idx;
+
if (class == BPF_ALU || class == BPF_ALU64) {
err = check_alu_op(env, insn);
if (err)
@@ -4851,13 +7596,13 @@
/* check that memory (src_reg + off) is readable,
* the state of dst_reg will be updated by this func
*/
- err = check_mem_access(env, insn_idx, insn->src_reg, insn->off,
- BPF_SIZE(insn->code), BPF_READ,
- insn->dst_reg, false);
+ err = check_mem_access(env, env->insn_idx, insn->src_reg,
+ insn->off, BPF_SIZE(insn->code),
+ BPF_READ, insn->dst_reg, false);
if (err)
return err;
- prev_src_type = &env->insn_aux_data[insn_idx].ptr_type;
+ prev_src_type = &env->insn_aux_data[env->insn_idx].ptr_type;
if (*prev_src_type == NOT_INIT) {
/* saw a valid insn
@@ -4866,9 +7611,7 @@
*/
*prev_src_type = src_reg_type;
- } else if (src_reg_type != *prev_src_type &&
- (src_reg_type == PTR_TO_CTX ||
- *prev_src_type == PTR_TO_CTX)) {
+ } else if (reg_type_mismatch(src_reg_type, *prev_src_type)) {
/* ABuser program is trying to use the same insn
* dst_reg = *(u32*) (src_reg + off)
* with different pointer types:
@@ -4884,10 +7627,10 @@
enum bpf_reg_type *prev_dst_type, dst_reg_type;
if (BPF_MODE(insn->code) == BPF_XADD) {
- err = check_xadd(env, insn_idx, insn);
+ err = check_xadd(env, env->insn_idx, insn);
if (err)
return err;
- insn_idx++;
+ env->insn_idx++;
continue;
}
@@ -4903,19 +7646,17 @@
dst_reg_type = regs[insn->dst_reg].type;
/* check that memory (dst_reg + off) is writeable */
- err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_WRITE,
- insn->src_reg, false);
+ err = check_mem_access(env, env->insn_idx, insn->dst_reg,
+ insn->off, BPF_SIZE(insn->code),
+ BPF_WRITE, insn->src_reg, false);
if (err)
return err;
- prev_dst_type = &env->insn_aux_data[insn_idx].ptr_type;
+ prev_dst_type = &env->insn_aux_data[env->insn_idx].ptr_type;
if (*prev_dst_type == NOT_INIT) {
*prev_dst_type = dst_reg_type;
- } else if (dst_reg_type != *prev_dst_type &&
- (dst_reg_type == PTR_TO_CTX ||
- *prev_dst_type == PTR_TO_CTX)) {
+ } else if (reg_type_mismatch(dst_reg_type, *prev_dst_type)) {
verbose(env, "same insn cannot be used with different pointers\n");
return -EINVAL;
}
@@ -4932,35 +7673,44 @@
return err;
if (is_ctx_reg(env, insn->dst_reg)) {
- verbose(env, "BPF_ST stores into R%d context is not allowed\n",
- insn->dst_reg);
+ verbose(env, "BPF_ST stores into R%d %s is not allowed\n",
+ insn->dst_reg,
+ reg_type_str[reg_state(env, insn->dst_reg)->type]);
return -EACCES;
}
/* check that memory (dst_reg + off) is writeable */
- err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
- BPF_SIZE(insn->code), BPF_WRITE,
- -1, false);
+ err = check_mem_access(env, env->insn_idx, insn->dst_reg,
+ insn->off, BPF_SIZE(insn->code),
+ BPF_WRITE, -1, false);
if (err)
return err;
- } else if (class == BPF_JMP) {
+ } else if (class == BPF_JMP || class == BPF_JMP32) {
u8 opcode = BPF_OP(insn->code);
+ env->jmps_processed++;
if (opcode == BPF_CALL) {
if (BPF_SRC(insn->code) != BPF_K ||
insn->off != 0 ||
(insn->src_reg != BPF_REG_0 &&
insn->src_reg != BPF_PSEUDO_CALL) ||
- insn->dst_reg != BPF_REG_0) {
+ insn->dst_reg != BPF_REG_0 ||
+ class == BPF_JMP32) {
verbose(env, "BPF_CALL uses reserved fields\n");
return -EINVAL;
}
+ if (env->cur_state->active_spin_lock &&
+ (insn->src_reg == BPF_PSEUDO_CALL ||
+ insn->imm != BPF_FUNC_spin_unlock)) {
+ verbose(env, "function calls are not allowed while holding a lock\n");
+ return -EINVAL;
+ }
if (insn->src_reg == BPF_PSEUDO_CALL)
- err = check_func_call(env, insn, &insn_idx);
+ err = check_func_call(env, insn, &env->insn_idx);
else
- err = check_helper_call(env, insn->imm, insn_idx);
+ err = check_helper_call(env, insn->imm, env->insn_idx);
if (err)
return err;
@@ -4968,33 +7718,43 @@
if (BPF_SRC(insn->code) != BPF_K ||
insn->imm != 0 ||
insn->src_reg != BPF_REG_0 ||
- insn->dst_reg != BPF_REG_0) {
+ insn->dst_reg != BPF_REG_0 ||
+ class == BPF_JMP32) {
verbose(env, "BPF_JA uses reserved fields\n");
return -EINVAL;
}
- insn_idx += insn->off + 1;
+ env->insn_idx += insn->off + 1;
continue;
} else if (opcode == BPF_EXIT) {
if (BPF_SRC(insn->code) != BPF_K ||
insn->imm != 0 ||
insn->src_reg != BPF_REG_0 ||
- insn->dst_reg != BPF_REG_0) {
+ insn->dst_reg != BPF_REG_0 ||
+ class == BPF_JMP32) {
verbose(env, "BPF_EXIT uses reserved fields\n");
return -EINVAL;
}
+ if (env->cur_state->active_spin_lock) {
+ verbose(env, "bpf_spin_unlock is missing\n");
+ return -EINVAL;
+ }
+
if (state->curframe) {
/* exit from nested function */
- prev_insn_idx = insn_idx;
- err = prepare_func_exit(env, &insn_idx);
+ err = prepare_func_exit(env, &env->insn_idx);
if (err)
return err;
do_print_state = true;
continue;
}
+ err = check_reference_leak(env);
+ if (err)
+ return err;
+
/* eBPF calling convetion is such that R0 is used
* to return the value from eBPF program.
* Make sure that it's readable at this time
@@ -5014,7 +7774,9 @@
if (err)
return err;
process_bpf_exit:
- err = pop_stack(env, &prev_insn_idx, &insn_idx);
+ update_branch_counts(env, env->cur_state);
+ err = pop_stack(env, &prev_insn_idx,
+ &env->insn_idx);
if (err < 0) {
if (err != -ENOENT)
return err;
@@ -5024,7 +7786,7 @@
continue;
}
} else {
- err = check_cond_jmp_op(env, insn, &insn_idx);
+ err = check_cond_jmp_op(env, insn, &env->insn_idx);
if (err)
return err;
}
@@ -5041,8 +7803,8 @@
if (err)
return err;
- insn_idx++;
- env->insn_aux_data[insn_idx].seen = true;
+ env->insn_idx++;
+ env->insn_aux_data[env->insn_idx].seen = true;
} else {
verbose(env, "invalid BPF_LD mode\n");
return -EINVAL;
@@ -5052,19 +7814,9 @@
return -EINVAL;
}
- insn_idx++;
+ env->insn_idx++;
}
- verbose(env, "processed %d insns (limit %d), stack depth ",
- insn_processed, BPF_COMPLEXITY_LIMIT_INSNS);
- for (i = 0; i < env->subprog_cnt; i++) {
- u32 depth = env->subprog_info[i].stack_depth;
-
- verbose(env, "%d", depth);
- if (i + 1 < env->subprog_cnt)
- verbose(env, "+");
- }
- verbose(env, "\n");
env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
return 0;
}
@@ -5077,6 +7829,19 @@
!(map->map_flags & BPF_F_NO_PREALLOC);
}
+static bool is_tracing_prog_type(enum bpf_prog_type type)
+{
+ switch (type) {
+ case BPF_PROG_TYPE_KPROBE:
+ case BPF_PROG_TYPE_TRACEPOINT:
+ case BPF_PROG_TYPE_PERF_EVENT:
+ case BPF_PROG_TYPE_RAW_TRACEPOINT:
+ return true;
+ default:
+ return false;
+ }
+}
+
static int check_map_prog_compatibility(struct bpf_verifier_env *env,
struct bpf_map *map,
struct bpf_prog *prog)
@@ -5099,6 +7864,13 @@
}
}
+ if ((is_tracing_prog_type(prog->type) ||
+ prog->type == BPF_PROG_TYPE_SOCKET_FILTER) &&
+ map_value_has_spin_lock(map)) {
+ verbose(env, "tracing progs cannot use bpf_spin_lock yet\n");
+ return -EINVAL;
+ }
+
if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) &&
!bpf_offload_prog_map_match(prog, map)) {
verbose(env, "offload device mismatch between prog and map\n");
@@ -5108,6 +7880,12 @@
return 0;
}
+static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
+{
+ return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
+ map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
+}
+
/* look for pseudo eBPF instructions that access map FDs and
* replace them with actual map pointers
*/
@@ -5136,8 +7914,10 @@
}
if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
+ struct bpf_insn_aux_data *aux;
struct bpf_map *map;
struct fd f;
+ u64 addr;
if (i == insn_cnt - 1 || insn[1].code != 0 ||
insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
@@ -5146,21 +7926,27 @@
return -EINVAL;
}
- if (insn->src_reg == 0)
+ if (insn[0].src_reg == 0)
/* valid generic load 64-bit imm */
goto next_insn;
- if (insn->src_reg != BPF_PSEUDO_MAP_FD) {
+ /* In final convert_pseudo_ld_imm64() step, this is
+ * converted into regular 64-bit imm load insn.
+ */
+ if ((insn[0].src_reg != BPF_PSEUDO_MAP_FD &&
+ insn[0].src_reg != BPF_PSEUDO_MAP_VALUE) ||
+ (insn[0].src_reg == BPF_PSEUDO_MAP_FD &&
+ insn[1].imm != 0)) {
verbose(env,
"unrecognized bpf_ld_imm64 insn\n");
return -EINVAL;
}
- f = fdget(insn->imm);
+ f = fdget(insn[0].imm);
map = __bpf_map_get(f);
if (IS_ERR(map)) {
verbose(env, "fd %d is not pointing to valid bpf_map\n",
- insn->imm);
+ insn[0].imm);
return PTR_ERR(map);
}
@@ -5170,16 +7956,47 @@
return err;
}
- /* store map pointer inside BPF_LD_IMM64 instruction */
- insn[0].imm = (u32) (unsigned long) map;
- insn[1].imm = ((u64) (unsigned long) map) >> 32;
+ aux = &env->insn_aux_data[i];
+ if (insn->src_reg == BPF_PSEUDO_MAP_FD) {
+ addr = (unsigned long)map;
+ } else {
+ u32 off = insn[1].imm;
+
+ if (off >= BPF_MAX_VAR_OFF) {
+ verbose(env, "direct value offset of %u is not allowed\n", off);
+ fdput(f);
+ return -EINVAL;
+ }
+
+ if (!map->ops->map_direct_value_addr) {
+ verbose(env, "no direct value access support for this map type\n");
+ fdput(f);
+ return -EINVAL;
+ }
+
+ err = map->ops->map_direct_value_addr(map, &addr, off);
+ if (err) {
+ verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
+ map->value_size, off);
+ fdput(f);
+ return err;
+ }
+
+ aux->map_off = off;
+ addr += off;
+ }
+
+ insn[0].imm = (u32)addr;
+ insn[1].imm = addr >> 32;
/* check whether we recorded this map already */
- for (j = 0; j < env->used_map_cnt; j++)
+ for (j = 0; j < env->used_map_cnt; j++) {
if (env->used_maps[j] == map) {
+ aux->map_index = j;
fdput(f);
goto next_insn;
}
+ }
if (env->used_map_cnt >= MAX_USED_MAPS) {
fdput(f);
@@ -5196,12 +8013,13 @@
fdput(f);
return PTR_ERR(map);
}
+
+ aux->map_index = env->used_map_cnt;
env->used_maps[env->used_map_cnt++] = map;
- if (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE &&
+ if (bpf_map_is_cgroup_storage(map) &&
bpf_cgroup_storage_assign(env->prog, map)) {
- verbose(env,
- "only one cgroup storage is allowed\n");
+ verbose(env, "only one cgroup storage of each type is allowed\n");
fdput(f);
return -EBUSY;
}
@@ -5230,11 +8048,15 @@
/* drop refcnt of maps used by the rejected program */
static void release_maps(struct bpf_verifier_env *env)
{
+ enum bpf_cgroup_storage_type stype;
int i;
- if (env->prog->aux->cgroup_storage)
+ for_each_cgroup_storage_type(stype) {
+ if (!env->prog->aux->cgroup_storage[stype])
+ continue;
bpf_cgroup_storage_release(env->prog,
- env->prog->aux->cgroup_storage);
+ env->prog->aux->cgroup_storage[stype]);
+ }
for (i = 0; i < env->used_map_cnt; i++)
bpf_map_put(env->used_maps[i]);
@@ -5256,14 +8078,23 @@
* insni[off, off + cnt). Adjust corresponding insn_aux_data by copying
* [0, off) and [off, end) to new locations, so the patched range stays zero
*/
-static int adjust_insn_aux_data(struct bpf_verifier_env *env, u32 prog_len,
- u32 off, u32 cnt)
+static int adjust_insn_aux_data(struct bpf_verifier_env *env,
+ struct bpf_prog *new_prog, u32 off, u32 cnt)
{
struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data;
+ struct bpf_insn *insn = new_prog->insnsi;
+ u32 prog_len;
int i;
+ /* aux info at OFF always needs adjustment, no matter fast path
+ * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
+ * original insn at old prog.
+ */
+ old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1);
+
if (cnt == 1)
return 0;
+ prog_len = new_prog->len;
new_data = vzalloc(array_size(prog_len,
sizeof(struct bpf_insn_aux_data)));
if (!new_data)
@@ -5271,8 +8102,10 @@
memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
memcpy(new_data + off + cnt - 1, old_data + off,
sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
- for (i = off; i < off + cnt - 1; i++)
+ for (i = off; i < off + cnt - 1; i++) {
new_data[i].seen = true;
+ new_data[i].zext_dst = insn_has_def32(env, insn + i);
+ }
env->insn_aux_data = new_data;
vfree(old_data);
return 0;
@@ -5298,14 +8131,166 @@
struct bpf_prog *new_prog;
new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
- if (!new_prog)
+ if (IS_ERR(new_prog)) {
+ if (PTR_ERR(new_prog) == -ERANGE)
+ verbose(env,
+ "insn %d cannot be patched due to 16-bit range\n",
+ env->insn_aux_data[off].orig_idx);
return NULL;
- if (adjust_insn_aux_data(env, new_prog->len, off, len))
+ }
+ if (adjust_insn_aux_data(env, new_prog, off, len))
return NULL;
adjust_subprog_starts(env, off, len);
return new_prog;
}
+static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env,
+ u32 off, u32 cnt)
+{
+ int i, j;
+
+ /* find first prog starting at or after off (first to remove) */
+ for (i = 0; i < env->subprog_cnt; i++)
+ if (env->subprog_info[i].start >= off)
+ break;
+ /* find first prog starting at or after off + cnt (first to stay) */
+ for (j = i; j < env->subprog_cnt; j++)
+ if (env->subprog_info[j].start >= off + cnt)
+ break;
+ /* if j doesn't start exactly at off + cnt, we are just removing
+ * the front of previous prog
+ */
+ if (env->subprog_info[j].start != off + cnt)
+ j--;
+
+ if (j > i) {
+ struct bpf_prog_aux *aux = env->prog->aux;
+ int move;
+
+ /* move fake 'exit' subprog as well */
+ move = env->subprog_cnt + 1 - j;
+
+ memmove(env->subprog_info + i,
+ env->subprog_info + j,
+ sizeof(*env->subprog_info) * move);
+ env->subprog_cnt -= j - i;
+
+ /* remove func_info */
+ if (aux->func_info) {
+ move = aux->func_info_cnt - j;
+
+ memmove(aux->func_info + i,
+ aux->func_info + j,
+ sizeof(*aux->func_info) * move);
+ aux->func_info_cnt -= j - i;
+ /* func_info->insn_off is set after all code rewrites,
+ * in adjust_btf_func() - no need to adjust
+ */
+ }
+ } else {
+ /* convert i from "first prog to remove" to "first to adjust" */
+ if (env->subprog_info[i].start == off)
+ i++;
+ }
+
+ /* update fake 'exit' subprog as well */
+ for (; i <= env->subprog_cnt; i++)
+ env->subprog_info[i].start -= cnt;
+
+ return 0;
+}
+
+static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off,
+ u32 cnt)
+{
+ struct bpf_prog *prog = env->prog;
+ u32 i, l_off, l_cnt, nr_linfo;
+ struct bpf_line_info *linfo;
+
+ nr_linfo = prog->aux->nr_linfo;
+ if (!nr_linfo)
+ return 0;
+
+ linfo = prog->aux->linfo;
+
+ /* find first line info to remove, count lines to be removed */
+ for (i = 0; i < nr_linfo; i++)
+ if (linfo[i].insn_off >= off)
+ break;
+
+ l_off = i;
+ l_cnt = 0;
+ for (; i < nr_linfo; i++)
+ if (linfo[i].insn_off < off + cnt)
+ l_cnt++;
+ else
+ break;
+
+ /* First live insn doesn't match first live linfo, it needs to "inherit"
+ * last removed linfo. prog is already modified, so prog->len == off
+ * means no live instructions after (tail of the program was removed).
+ */
+ if (prog->len != off && l_cnt &&
+ (i == nr_linfo || linfo[i].insn_off != off + cnt)) {
+ l_cnt--;
+ linfo[--i].insn_off = off + cnt;
+ }
+
+ /* remove the line info which refer to the removed instructions */
+ if (l_cnt) {
+ memmove(linfo + l_off, linfo + i,
+ sizeof(*linfo) * (nr_linfo - i));
+
+ prog->aux->nr_linfo -= l_cnt;
+ nr_linfo = prog->aux->nr_linfo;
+ }
+
+ /* pull all linfo[i].insn_off >= off + cnt in by cnt */
+ for (i = l_off; i < nr_linfo; i++)
+ linfo[i].insn_off -= cnt;
+
+ /* fix up all subprogs (incl. 'exit') which start >= off */
+ for (i = 0; i <= env->subprog_cnt; i++)
+ if (env->subprog_info[i].linfo_idx > l_off) {
+ /* program may have started in the removed region but
+ * may not be fully removed
+ */
+ if (env->subprog_info[i].linfo_idx >= l_off + l_cnt)
+ env->subprog_info[i].linfo_idx -= l_cnt;
+ else
+ env->subprog_info[i].linfo_idx = l_off;
+ }
+
+ return 0;
+}
+
+static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
+{
+ struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+ unsigned int orig_prog_len = env->prog->len;
+ int err;
+
+ if (bpf_prog_is_dev_bound(env->prog->aux))
+ bpf_prog_offload_remove_insns(env, off, cnt);
+
+ err = bpf_remove_insns(env->prog, off, cnt);
+ if (err)
+ return err;
+
+ err = adjust_subprog_starts_after_remove(env, off, cnt);
+ if (err)
+ return err;
+
+ err = bpf_adj_linfo_after_remove(env, off, cnt);
+ if (err)
+ return err;
+
+ memmove(aux_data + off, aux_data + off + cnt,
+ sizeof(*aux_data) * (orig_prog_len - off - cnt));
+
+ return 0;
+}
+
/* The verifier does more data flow analysis than llvm and will not
* explore branches that are dead at run time. Malicious programs can
* have dead code too. Therefore replace all dead at-run-time code
@@ -5332,8 +8317,173 @@
}
}
-/* convert load instructions that access fields of 'struct __sk_buff'
- * into sequence of instructions that access fields of 'struct sk_buff'
+static bool insn_is_cond_jump(u8 code)
+{
+ u8 op;
+
+ if (BPF_CLASS(code) == BPF_JMP32)
+ return true;
+
+ if (BPF_CLASS(code) != BPF_JMP)
+ return false;
+
+ op = BPF_OP(code);
+ return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
+}
+
+static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
+{
+ struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+ struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
+ struct bpf_insn *insn = env->prog->insnsi;
+ const int insn_cnt = env->prog->len;
+ int i;
+
+ for (i = 0; i < insn_cnt; i++, insn++) {
+ if (!insn_is_cond_jump(insn->code))
+ continue;
+
+ if (!aux_data[i + 1].seen)
+ ja.off = insn->off;
+ else if (!aux_data[i + 1 + insn->off].seen)
+ ja.off = 0;
+ else
+ continue;
+
+ if (bpf_prog_is_dev_bound(env->prog->aux))
+ bpf_prog_offload_replace_insn(env, i, &ja);
+
+ memcpy(insn, &ja, sizeof(ja));
+ }
+}
+
+static int opt_remove_dead_code(struct bpf_verifier_env *env)
+{
+ struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+ int insn_cnt = env->prog->len;
+ int i, err;
+
+ for (i = 0; i < insn_cnt; i++) {
+ int j;
+
+ j = 0;
+ while (i + j < insn_cnt && !aux_data[i + j].seen)
+ j++;
+ if (!j)
+ continue;
+
+ err = verifier_remove_insns(env, i, j);
+ if (err)
+ return err;
+ insn_cnt = env->prog->len;
+ }
+
+ return 0;
+}
+
+static int opt_remove_nops(struct bpf_verifier_env *env)
+{
+ const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
+ struct bpf_insn *insn = env->prog->insnsi;
+ int insn_cnt = env->prog->len;
+ int i, err;
+
+ for (i = 0; i < insn_cnt; i++) {
+ if (memcmp(&insn[i], &ja, sizeof(ja)))
+ continue;
+
+ err = verifier_remove_insns(env, i, 1);
+ if (err)
+ return err;
+ insn_cnt--;
+ i--;
+ }
+
+ return 0;
+}
+
+static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env,
+ const union bpf_attr *attr)
+{
+ struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4];
+ struct bpf_insn_aux_data *aux = env->insn_aux_data;
+ int i, patch_len, delta = 0, len = env->prog->len;
+ struct bpf_insn *insns = env->prog->insnsi;
+ struct bpf_prog *new_prog;
+ bool rnd_hi32;
+
+ rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32;
+ zext_patch[1] = BPF_ZEXT_REG(0);
+ rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0);
+ rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
+ rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX);
+ for (i = 0; i < len; i++) {
+ int adj_idx = i + delta;
+ struct bpf_insn insn;
+
+ insn = insns[adj_idx];
+ if (!aux[adj_idx].zext_dst) {
+ u8 code, class;
+ u32 imm_rnd;
+
+ if (!rnd_hi32)
+ continue;
+
+ code = insn.code;
+ class = BPF_CLASS(code);
+ if (insn_no_def(&insn))
+ continue;
+
+ /* NOTE: arg "reg" (the fourth one) is only used for
+ * BPF_STX which has been ruled out in above
+ * check, it is safe to pass NULL here.
+ */
+ if (is_reg64(env, &insn, insn.dst_reg, NULL, DST_OP)) {
+ if (class == BPF_LD &&
+ BPF_MODE(code) == BPF_IMM)
+ i++;
+ continue;
+ }
+
+ /* ctx load could be transformed into wider load. */
+ if (class == BPF_LDX &&
+ aux[adj_idx].ptr_type == PTR_TO_CTX)
+ continue;
+
+ imm_rnd = get_random_int();
+ rnd_hi32_patch[0] = insn;
+ rnd_hi32_patch[1].imm = imm_rnd;
+ rnd_hi32_patch[3].dst_reg = insn.dst_reg;
+ patch = rnd_hi32_patch;
+ patch_len = 4;
+ goto apply_patch_buffer;
+ }
+
+ if (!bpf_jit_needs_zext())
+ continue;
+
+ zext_patch[0] = insn;
+ zext_patch[1].dst_reg = insn.dst_reg;
+ zext_patch[1].src_reg = insn.dst_reg;
+ patch = zext_patch;
+ patch_len = 2;
+apply_patch_buffer:
+ new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len);
+ if (!new_prog)
+ return -ENOMEM;
+ env->prog = new_prog;
+ insns = new_prog->insnsi;
+ aux = env->insn_aux_data;
+ delta += patch_len - 1;
+ }
+
+ return 0;
+}
+
+/* convert load instructions that access fields of a context type into a
+ * sequence of instructions that access fields of the underlying structure:
+ * struct __sk_buff -> struct sk_buff
+ * struct bpf_sock_ops -> struct sock
*/
static int convert_ctx_accesses(struct bpf_verifier_env *env)
{
@@ -5341,12 +8491,16 @@
int i, cnt, size, ctx_field_size, delta = 0;
const int insn_cnt = env->prog->len;
struct bpf_insn insn_buf[16], *insn;
+ u32 target_size, size_default, off;
struct bpf_prog *new_prog;
enum bpf_access_type type;
bool is_narrower_load;
- u32 target_size;
- if (ops->gen_prologue) {
+ if (ops->gen_prologue || env->seen_direct_write) {
+ if (!ops->gen_prologue) {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
env->prog);
if (cnt >= ARRAY_SIZE(insn_buf)) {
@@ -5362,12 +8516,14 @@
}
}
- if (!ops->convert_ctx_access || bpf_prog_is_dev_bound(env->prog->aux))
+ if (bpf_prog_is_dev_bound(env->prog->aux))
return 0;
insn = env->prog->insnsi + delta;
for (i = 0; i < insn_cnt; i++, insn++) {
+ bpf_convert_ctx_access_t convert_ctx_access;
+
if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
@@ -5409,8 +8565,25 @@
continue;
}
- if (env->insn_aux_data[i + delta].ptr_type != PTR_TO_CTX)
+ switch (env->insn_aux_data[i + delta].ptr_type) {
+ case PTR_TO_CTX:
+ if (!ops->convert_ctx_access)
+ continue;
+ convert_ctx_access = ops->convert_ctx_access;
+ break;
+ case PTR_TO_SOCKET:
+ case PTR_TO_SOCK_COMMON:
+ convert_ctx_access = bpf_sock_convert_ctx_access;
+ break;
+ case PTR_TO_TCP_SOCK:
+ convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
+ break;
+ case PTR_TO_XDP_SOCK:
+ convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
+ break;
+ default:
continue;
+ }
ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size;
size = BPF_LDST_BYTES(insn);
@@ -5421,9 +8594,9 @@
* we will apply proper mask to the result.
*/
is_narrower_load = size < ctx_field_size;
+ size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
+ off = insn->off;
if (is_narrower_load) {
- u32 size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
- u32 off = insn->off;
u8 size_code;
if (type == BPF_WRITE) {
@@ -5442,8 +8615,8 @@
}
target_size = 0;
- cnt = ops->convert_ctx_access(type, insn, insn_buf, env->prog,
- &target_size);
+ cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
+ &target_size);
if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) ||
(ctx_field_size && !target_size)) {
verbose(env, "bpf verifier is misconfigured\n");
@@ -5451,12 +8624,23 @@
}
if (is_narrower_load && size < target_size) {
- if (ctx_field_size <= 4)
+ u8 shift = bpf_ctx_narrow_access_offset(
+ off, size, size_default) * 8;
+ if (ctx_field_size <= 4) {
+ if (shift)
+ insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
+ insn->dst_reg,
+ shift);
insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
(1 << size * 8) - 1);
- else
+ } else {
+ if (shift)
+ insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
+ insn->dst_reg,
+ shift);
insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg,
- (1 << size * 8) - 1);
+ (1ULL << size * 8) - 1);
+ }
}
new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
@@ -5479,7 +8663,7 @@
int i, j, subprog_start, subprog_end = 0, len, subprog;
struct bpf_insn *insn;
void *old_bpf_func;
- int err = -ENOMEM;
+ int err;
if (env->subprog_cnt <= 1)
return 0;
@@ -5510,6 +8694,11 @@
insn->imm = 1;
}
+ err = bpf_prog_alloc_jited_linfo(prog);
+ if (err)
+ goto out_undo_insn;
+
+ err = -ENOMEM;
func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL);
if (!func)
goto out_undo_insn;
@@ -5519,7 +8708,12 @@
subprog_end = env->subprog_info[i + 1].start;
len = subprog_end - subprog_start;
- func[i] = bpf_prog_alloc(bpf_prog_size(len), GFP_USER);
+ /* BPF_PROG_RUN doesn't call subprogs directly,
+ * hence main prog stats include the runtime of subprogs.
+ * subprogs don't have IDs and not reachable via prog_get_next_id
+ * func[i]->aux->stats will never be accessed and stays NULL
+ */
+ func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER);
if (!func[i])
goto out_free;
memcpy(func[i]->insnsi, &prog->insnsi[subprog_start],
@@ -5529,12 +8723,21 @@
if (bpf_prog_calc_tag(func[i]))
goto out_free;
func[i]->is_func = 1;
+ func[i]->aux->func_idx = i;
+ /* the btf and func_info will be freed only at prog->aux */
+ func[i]->aux->btf = prog->aux->btf;
+ func[i]->aux->func_info = prog->aux->func_info;
+
/* Use bpf_prog_F_tag to indicate functions in stack traces.
* Long term would need debug info to populate names
*/
func[i]->aux->name[0] = 'F';
func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
func[i]->jit_requested = 1;
+ func[i]->aux->linfo = prog->aux->linfo;
+ func[i]->aux->nr_linfo = prog->aux->nr_linfo;
+ func[i]->aux->jited_linfo = prog->aux->jited_linfo;
+ func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
func[i] = bpf_int_jit_compile(func[i]);
if (!func[i]->jited) {
err = -ENOTSUPP;
@@ -5553,9 +8756,8 @@
insn->src_reg != BPF_PSEUDO_CALL)
continue;
subprog = insn->off;
- insn->imm = (u64 (*)(u64, u64, u64, u64, u64))
- func[subprog]->bpf_func -
- __bpf_call_base;
+ insn->imm = BPF_CAST_CALL(func[subprog]->bpf_func) -
+ __bpf_call_base;
}
/* we use the aux data to keep a list of the start addresses
@@ -5608,6 +8810,7 @@
prog->bpf_func = func[0]->bpf_func;
prog->aux->func = func;
prog->aux->func_cnt = env->subprog_cnt;
+ bpf_prog_free_unused_jited_linfo(prog);
return 0;
out_free:
for (i = 0; i < env->subprog_cnt; i++)
@@ -5624,6 +8827,7 @@
insn->off = 0;
insn->imm = env->insn_aux_data[i].call_imm;
}
+ bpf_prog_free_jited_linfo(prog);
return err;
}
@@ -5634,10 +8838,10 @@
struct bpf_insn *insn = prog->insnsi;
int i, depth;
#endif
- int err;
+ int err = 0;
- err = 0;
- if (env->prog->jit_requested) {
+ if (env->prog->jit_requested &&
+ !bpf_prog_is_dev_bound(env->prog->aux)) {
err = jit_subprogs(env);
if (err == 0)
return 0;
@@ -5737,6 +8941,58 @@
continue;
}
+ if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) ||
+ insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) {
+ const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
+ const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
+ struct bpf_insn insn_buf[16];
+ struct bpf_insn *patch = &insn_buf[0];
+ bool issrc, isneg;
+ u32 off_reg;
+
+ aux = &env->insn_aux_data[i + delta];
+ if (!aux->alu_state ||
+ aux->alu_state == BPF_ALU_NON_POINTER)
+ continue;
+
+ isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
+ issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
+ BPF_ALU_SANITIZE_SRC;
+
+ off_reg = issrc ? insn->src_reg : insn->dst_reg;
+ if (isneg)
+ *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+ *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1);
+ *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
+ *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
+ *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
+ *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
+ if (issrc) {
+ *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX,
+ off_reg);
+ insn->src_reg = BPF_REG_AX;
+ } else {
+ *patch++ = BPF_ALU64_REG(BPF_AND, off_reg,
+ BPF_REG_AX);
+ }
+ if (isneg)
+ insn->code = insn->code == code_add ?
+ code_sub : code_add;
+ *patch++ = *insn;
+ if (issrc && isneg)
+ *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+ cnt = patch - insn_buf;
+
+ new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+
+ delta += cnt - 1;
+ env->prog = prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ continue;
+ }
+
if (insn->code != (BPF_JMP | BPF_CALL))
continue;
if (insn->src_reg == BPF_PSEUDO_CALL)
@@ -5756,6 +9012,7 @@
*/
prog->cb_access = 1;
env->prog->aux->stack_depth = MAX_BPF_STACK;
+ env->prog->aux->max_pkt_offset = MAX_PACKET_OFF;
/* mark bpf_tail_call as different opcode to avoid
* conditional branch in the interpeter for every normal
@@ -5806,7 +9063,10 @@
if (prog->jit_requested && BITS_PER_LONG == 64 &&
(insn->imm == BPF_FUNC_map_lookup_elem ||
insn->imm == BPF_FUNC_map_update_elem ||
- insn->imm == BPF_FUNC_map_delete_elem)) {
+ insn->imm == BPF_FUNC_map_delete_elem ||
+ insn->imm == BPF_FUNC_map_push_elem ||
+ insn->imm == BPF_FUNC_map_pop_elem ||
+ insn->imm == BPF_FUNC_map_peek_elem)) {
aux = &env->insn_aux_data[i + delta];
if (bpf_map_ptr_poisoned(aux))
goto patch_call_imm;
@@ -5839,6 +9099,14 @@
BUILD_BUG_ON(!__same_type(ops->map_update_elem,
(int (*)(struct bpf_map *map, void *key, void *value,
u64 flags))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_push_elem,
+ (int (*)(struct bpf_map *map, void *value,
+ u64 flags))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_pop_elem,
+ (int (*)(struct bpf_map *map, void *value))NULL));
+ BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
+ (int (*)(struct bpf_map *map, void *value))NULL));
+
switch (insn->imm) {
case BPF_FUNC_map_lookup_elem:
insn->imm = BPF_CAST_CALL(ops->map_lookup_elem) -
@@ -5852,6 +9120,18 @@
insn->imm = BPF_CAST_CALL(ops->map_delete_elem) -
__bpf_call_base;
continue;
+ case BPF_FUNC_map_push_elem:
+ insn->imm = BPF_CAST_CALL(ops->map_push_elem) -
+ __bpf_call_base;
+ continue;
+ case BPF_FUNC_map_pop_elem:
+ insn->imm = BPF_CAST_CALL(ops->map_pop_elem) -
+ __bpf_call_base;
+ continue;
+ case BPF_FUNC_map_peek_elem:
+ insn->imm = BPF_CAST_CALL(ops->map_peek_elem) -
+ __bpf_call_base;
+ continue;
}
goto patch_call_imm;
@@ -5879,29 +9159,63 @@
struct bpf_verifier_state_list *sl, *sln;
int i;
+ sl = env->free_list;
+ while (sl) {
+ sln = sl->next;
+ free_verifier_state(&sl->state, false);
+ kfree(sl);
+ sl = sln;
+ }
+
if (!env->explored_states)
return;
- for (i = 0; i < env->prog->len; i++) {
+ for (i = 0; i < state_htab_size(env); i++) {
sl = env->explored_states[i];
- if (sl)
- while (sl != STATE_LIST_MARK) {
- sln = sl->next;
- free_verifier_state(&sl->state, false);
- kfree(sl);
- sl = sln;
- }
+ while (sl) {
+ sln = sl->next;
+ free_verifier_state(&sl->state, false);
+ kfree(sl);
+ sl = sln;
+ }
}
- kfree(env->explored_states);
+ kvfree(env->explored_states);
}
-int bpf_check(struct bpf_prog **prog, union bpf_attr *attr)
+static void print_verification_stats(struct bpf_verifier_env *env)
{
+ int i;
+
+ if (env->log.level & BPF_LOG_STATS) {
+ verbose(env, "verification time %lld usec\n",
+ div_u64(env->verification_time, 1000));
+ verbose(env, "stack depth ");
+ for (i = 0; i < env->subprog_cnt; i++) {
+ u32 depth = env->subprog_info[i].stack_depth;
+
+ verbose(env, "%d", depth);
+ if (i + 1 < env->subprog_cnt)
+ verbose(env, "+");
+ }
+ verbose(env, "\n");
+ }
+ verbose(env, "processed %d insns (limit %d) max_states_per_insn %d "
+ "total_states %d peak_states %d mark_read %d\n",
+ env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS,
+ env->max_states_per_insn, env->total_states,
+ env->peak_states, env->longest_mark_read_walk);
+}
+
+int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ u64 start_time = ktime_get_ns();
struct bpf_verifier_env *env;
struct bpf_verifier_log *log;
- int ret = -EINVAL;
+ int i, len, ret = -EINVAL;
+ bool is_priv;
/* no program is valid */
if (ARRAY_SIZE(bpf_verifier_ops) == 0)
@@ -5915,17 +9229,21 @@
return -ENOMEM;
log = &env->log;
+ len = (*prog)->len;
env->insn_aux_data =
- vzalloc(array_size(sizeof(struct bpf_insn_aux_data),
- (*prog)->len));
+ vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len));
ret = -ENOMEM;
if (!env->insn_aux_data)
goto err_free_env;
+ for (i = 0; i < len; i++)
+ env->insn_aux_data[i].orig_idx = i;
env->prog = *prog;
env->ops = bpf_verifier_ops[env->prog->type];
+ is_priv = capable(CAP_SYS_ADMIN);
/* grab the mutex to protect few globals used by verifier */
- mutex_lock(&bpf_verifier_lock);
+ if (!is_priv)
+ mutex_lock(&bpf_verifier_lock);
if (attr->log_level || attr->log_buf || attr->log_size) {
/* user requested verbose verifier output
@@ -5937,33 +9255,46 @@
ret = -EINVAL;
/* log attributes have to be sane */
- if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
- !log->level || !log->ubuf)
+ if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 ||
+ !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK)
goto err_unlock;
}
env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
env->strict_alignment = true;
+ if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
+ env->strict_alignment = false;
+
+ env->allow_ptr_leaks = is_priv;
+
+ if (is_priv)
+ env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
ret = replace_map_fd_with_map_ptr(env);
if (ret < 0)
goto skip_full_check;
if (bpf_prog_is_dev_bound(env->prog->aux)) {
- ret = bpf_prog_offload_verifier_prep(env);
+ ret = bpf_prog_offload_verifier_prep(env->prog);
if (ret)
goto skip_full_check;
}
- env->explored_states = kcalloc(env->prog->len,
+ env->explored_states = kvcalloc(state_htab_size(env),
sizeof(struct bpf_verifier_state_list *),
GFP_USER);
ret = -ENOMEM;
if (!env->explored_states)
goto skip_full_check;
- env->allow_ptr_leaks = capable(CAP_SYS_ADMIN);
+ ret = check_subprogs(env);
+ if (ret < 0)
+ goto skip_full_check;
+
+ ret = check_btf_info(env, attr, uattr);
+ if (ret < 0)
+ goto skip_full_check;
ret = check_cfg(env);
if (ret < 0)
@@ -5975,16 +9306,29 @@
env->cur_state = NULL;
}
+ if (ret == 0 && bpf_prog_is_dev_bound(env->prog->aux))
+ ret = bpf_prog_offload_finalize(env);
+
skip_full_check:
while (!pop_stack(env, NULL, NULL));
free_states(env);
if (ret == 0)
- sanitize_dead_code(env);
-
- if (ret == 0)
ret = check_max_stack_depth(env);
+ /* instruction rewrites happen after this point */
+ if (is_priv) {
+ if (ret == 0)
+ opt_hard_wire_dead_code_branches(env);
+ if (ret == 0)
+ ret = opt_remove_dead_code(env);
+ if (ret == 0)
+ ret = opt_remove_nops(env);
+ } else {
+ if (ret == 0)
+ sanitize_dead_code(env);
+ }
+
if (ret == 0)
/* program is valid, convert *(u32*)(ctx + off) accesses */
ret = convert_ctx_accesses(env);
@@ -5992,9 +9336,21 @@
if (ret == 0)
ret = fixup_bpf_calls(env);
+ /* do 32-bit optimization after insn patching has done so those patched
+ * insns could be handled correctly.
+ */
+ if (ret == 0 && !bpf_prog_is_dev_bound(env->prog->aux)) {
+ ret = opt_subreg_zext_lo32_rnd_hi32(env, attr);
+ env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret
+ : false;
+ }
+
if (ret == 0)
ret = fixup_call_args(env);
+ env->verification_time = ktime_get_ns() - start_time;
+ print_verification_stats(env);
+
if (log->level && bpf_verifier_log_full(log))
ret = -ENOSPC;
if (log->level && !log->ubuf) {
@@ -6023,6 +9379,9 @@
convert_pseudo_ld_imm64(env);
}
+ if (ret == 0)
+ adjust_btf_func(env);
+
err_release_maps:
if (!env->prog->aux->used_maps)
/* if we didn't copy map pointers into bpf_prog_info, release
@@ -6031,7 +9390,8 @@
release_maps(env);
*prog = env->prog;
err_unlock:
- mutex_unlock(&bpf_verifier_lock);
+ if (!is_priv)
+ mutex_unlock(&bpf_verifier_lock);
vfree(env->insn_aux_data);
err_free_env:
kfree(env);