v4.19.13 snapshot.
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
new file mode 100644
index 0000000..138f030
--- /dev/null
+++ b/kernel/bpf/btf.c
@@ -0,0 +1,2360 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018 Facebook */
+
+#include <uapi/linux/btf.h>
+#include <uapi/linux/types.h>
+#include <linux/seq_file.h>
+#include <linux/compiler.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/idr.h>
+#include <linux/sort.h>
+#include <linux/bpf_verifier.h>
+#include <linux/btf.h>
+
+/* BTF (BPF Type Format) is the meta data format which describes
+ * the data types of BPF program/map. Hence, it basically focus
+ * on the C programming language which the modern BPF is primary
+ * using.
+ *
+ * ELF Section:
+ * ~~~~~~~~~~~
+ * The BTF data is stored under the ".BTF" ELF section
+ *
+ * struct btf_type:
+ * ~~~~~~~~~~~~~~~
+ * Each 'struct btf_type' object describes a C data type.
+ * Depending on the type it is describing, a 'struct btf_type'
+ * object may be followed by more data. F.e.
+ * To describe an array, 'struct btf_type' is followed by
+ * 'struct btf_array'.
+ *
+ * 'struct btf_type' and any extra data following it are
+ * 4 bytes aligned.
+ *
+ * Type section:
+ * ~~~~~~~~~~~~~
+ * The BTF type section contains a list of 'struct btf_type' objects.
+ * Each one describes a C type. Recall from the above section
+ * that a 'struct btf_type' object could be immediately followed by extra
+ * data in order to desribe some particular C types.
+ *
+ * type_id:
+ * ~~~~~~~
+ * Each btf_type object is identified by a type_id. The type_id
+ * is implicitly implied by the location of the btf_type object in
+ * the BTF type section. The first one has type_id 1. The second
+ * one has type_id 2...etc. Hence, an earlier btf_type has
+ * a smaller type_id.
+ *
+ * A btf_type object may refer to another btf_type object by using
+ * type_id (i.e. the "type" in the "struct btf_type").
+ *
+ * NOTE that we cannot assume any reference-order.
+ * A btf_type object can refer to an earlier btf_type object
+ * but it can also refer to a later btf_type object.
+ *
+ * For example, to describe "const void *". A btf_type
+ * object describing "const" may refer to another btf_type
+ * object describing "void *". This type-reference is done
+ * by specifying type_id:
+ *
+ * [1] CONST (anon) type_id=2
+ * [2] PTR (anon) type_id=0
+ *
+ * The above is the btf_verifier debug log:
+ * - Each line started with "[?]" is a btf_type object
+ * - [?] is the type_id of the btf_type object.
+ * - CONST/PTR is the BTF_KIND_XXX
+ * - "(anon)" is the name of the type. It just
+ * happens that CONST and PTR has no name.
+ * - type_id=XXX is the 'u32 type' in btf_type
+ *
+ * NOTE: "void" has type_id 0
+ *
+ * String section:
+ * ~~~~~~~~~~~~~~
+ * The BTF string section contains the names used by the type section.
+ * Each string is referred by an "offset" from the beginning of the
+ * string section.
+ *
+ * Each string is '\0' terminated.
+ *
+ * The first character in the string section must be '\0'
+ * which is used to mean 'anonymous'. Some btf_type may not
+ * have a name.
+ */
+
+/* BTF verification:
+ *
+ * To verify BTF data, two passes are needed.
+ *
+ * Pass #1
+ * ~~~~~~~
+ * The first pass is to collect all btf_type objects to
+ * an array: "btf->types".
+ *
+ * Depending on the C type that a btf_type is describing,
+ * a btf_type may be followed by extra data. We don't know
+ * how many btf_type is there, and more importantly we don't
+ * know where each btf_type is located in the type section.
+ *
+ * Without knowing the location of each type_id, most verifications
+ * cannot be done. e.g. an earlier btf_type may refer to a later
+ * btf_type (recall the "const void *" above), so we cannot
+ * check this type-reference in the first pass.
+ *
+ * In the first pass, it still does some verifications (e.g.
+ * checking the name is a valid offset to the string section).
+ *
+ * Pass #2
+ * ~~~~~~~
+ * The main focus is to resolve a btf_type that is referring
+ * to another type.
+ *
+ * We have to ensure the referring type:
+ * 1) does exist in the BTF (i.e. in btf->types[])
+ * 2) does not cause a loop:
+ * struct A {
+ * struct B b;
+ * };
+ *
+ * struct B {
+ * struct A a;
+ * };
+ *
+ * btf_type_needs_resolve() decides if a btf_type needs
+ * to be resolved.
+ *
+ * The needs_resolve type implements the "resolve()" ops which
+ * essentially does a DFS and detects backedge.
+ *
+ * During resolve (or DFS), different C types have different
+ * "RESOLVED" conditions.
+ *
+ * When resolving a BTF_KIND_STRUCT, we need to resolve all its
+ * members because a member is always referring to another
+ * type. A struct's member can be treated as "RESOLVED" if
+ * it is referring to a BTF_KIND_PTR. Otherwise, the
+ * following valid C struct would be rejected:
+ *
+ * struct A {
+ * int m;
+ * struct A *a;
+ * };
+ *
+ * When resolving a BTF_KIND_PTR, it needs to keep resolving if
+ * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
+ * detect a pointer loop, e.g.:
+ * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
+ * ^ |
+ * +-----------------------------------------+
+ *
+ */
+
+#define BITS_PER_U64 (sizeof(u64) * BITS_PER_BYTE)
+#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
+#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
+#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
+#define BITS_ROUNDUP_BYTES(bits) \
+ (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
+
+#define BTF_INFO_MASK 0x0f00ffff
+#define BTF_INT_MASK 0x0fffffff
+#define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
+#define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
+
+/* 16MB for 64k structs and each has 16 members and
+ * a few MB spaces for the string section.
+ * The hard limit is S32_MAX.
+ */
+#define BTF_MAX_SIZE (16 * 1024 * 1024)
+
+#define for_each_member(i, struct_type, member) \
+ for (i = 0, member = btf_type_member(struct_type); \
+ i < btf_type_vlen(struct_type); \
+ i++, member++)
+
+#define for_each_member_from(i, from, struct_type, member) \
+ for (i = from, member = btf_type_member(struct_type) + from; \
+ i < btf_type_vlen(struct_type); \
+ i++, member++)
+
+static DEFINE_IDR(btf_idr);
+static DEFINE_SPINLOCK(btf_idr_lock);
+
+struct btf {
+ void *data;
+ struct btf_type **types;
+ u32 *resolved_ids;
+ u32 *resolved_sizes;
+ const char *strings;
+ void *nohdr_data;
+ struct btf_header hdr;
+ u32 nr_types;
+ u32 types_size;
+ u32 data_size;
+ refcount_t refcnt;
+ u32 id;
+ struct rcu_head rcu;
+};
+
+enum verifier_phase {
+ CHECK_META,
+ CHECK_TYPE,
+};
+
+struct resolve_vertex {
+ const struct btf_type *t;
+ u32 type_id;
+ u16 next_member;
+};
+
+enum visit_state {
+ NOT_VISITED,
+ VISITED,
+ RESOLVED,
+};
+
+enum resolve_mode {
+ RESOLVE_TBD, /* To Be Determined */
+ RESOLVE_PTR, /* Resolving for Pointer */
+ RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
+ * or array
+ */
+};
+
+#define MAX_RESOLVE_DEPTH 32
+
+struct btf_sec_info {
+ u32 off;
+ u32 len;
+};
+
+struct btf_verifier_env {
+ struct btf *btf;
+ u8 *visit_states;
+ struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
+ struct bpf_verifier_log log;
+ u32 log_type_id;
+ u32 top_stack;
+ enum verifier_phase phase;
+ enum resolve_mode resolve_mode;
+};
+
+static const char * const btf_kind_str[NR_BTF_KINDS] = {
+ [BTF_KIND_UNKN] = "UNKNOWN",
+ [BTF_KIND_INT] = "INT",
+ [BTF_KIND_PTR] = "PTR",
+ [BTF_KIND_ARRAY] = "ARRAY",
+ [BTF_KIND_STRUCT] = "STRUCT",
+ [BTF_KIND_UNION] = "UNION",
+ [BTF_KIND_ENUM] = "ENUM",
+ [BTF_KIND_FWD] = "FWD",
+ [BTF_KIND_TYPEDEF] = "TYPEDEF",
+ [BTF_KIND_VOLATILE] = "VOLATILE",
+ [BTF_KIND_CONST] = "CONST",
+ [BTF_KIND_RESTRICT] = "RESTRICT",
+};
+
+struct btf_kind_operations {
+ s32 (*check_meta)(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 meta_left);
+ int (*resolve)(struct btf_verifier_env *env,
+ const struct resolve_vertex *v);
+ int (*check_member)(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const struct btf_type *member_type);
+ void (*log_details)(struct btf_verifier_env *env,
+ const struct btf_type *t);
+ void (*seq_show)(const struct btf *btf, const struct btf_type *t,
+ u32 type_id, void *data, u8 bits_offsets,
+ struct seq_file *m);
+};
+
+static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
+static struct btf_type btf_void;
+
+static bool btf_type_is_modifier(const struct btf_type *t)
+{
+ /* Some of them is not strictly a C modifier
+ * but they are grouped into the same bucket
+ * for BTF concern:
+ * A type (t) that refers to another
+ * type through t->type AND its size cannot
+ * be determined without following the t->type.
+ *
+ * ptr does not fall into this bucket
+ * because its size is always sizeof(void *).
+ */
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_TYPEDEF:
+ case BTF_KIND_VOLATILE:
+ case BTF_KIND_CONST:
+ case BTF_KIND_RESTRICT:
+ return true;
+ }
+
+ return false;
+}
+
+static bool btf_type_is_void(const struct btf_type *t)
+{
+ /* void => no type and size info.
+ * Hence, FWD is also treated as void.
+ */
+ return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
+}
+
+static bool btf_type_is_void_or_null(const struct btf_type *t)
+{
+ return !t || btf_type_is_void(t);
+}
+
+/* union is only a special case of struct:
+ * all its offsetof(member) == 0
+ */
+static bool btf_type_is_struct(const struct btf_type *t)
+{
+ u8 kind = BTF_INFO_KIND(t->info);
+
+ return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
+}
+
+static bool btf_type_is_array(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
+}
+
+static bool btf_type_is_ptr(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
+}
+
+static bool btf_type_is_int(const struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
+}
+
+/* What types need to be resolved?
+ *
+ * btf_type_is_modifier() is an obvious one.
+ *
+ * btf_type_is_struct() because its member refers to
+ * another type (through member->type).
+
+ * btf_type_is_array() because its element (array->type)
+ * refers to another type. Array can be thought of a
+ * special case of struct while array just has the same
+ * member-type repeated by array->nelems of times.
+ */
+static bool btf_type_needs_resolve(const struct btf_type *t)
+{
+ return btf_type_is_modifier(t) ||
+ btf_type_is_ptr(t) ||
+ btf_type_is_struct(t) ||
+ btf_type_is_array(t);
+}
+
+/* t->size can be used */
+static bool btf_type_has_size(const struct btf_type *t)
+{
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_INT:
+ case BTF_KIND_STRUCT:
+ case BTF_KIND_UNION:
+ case BTF_KIND_ENUM:
+ return true;
+ }
+
+ return false;
+}
+
+static const char *btf_int_encoding_str(u8 encoding)
+{
+ if (encoding == 0)
+ return "(none)";
+ else if (encoding == BTF_INT_SIGNED)
+ return "SIGNED";
+ else if (encoding == BTF_INT_CHAR)
+ return "CHAR";
+ else if (encoding == BTF_INT_BOOL)
+ return "BOOL";
+ else
+ return "UNKN";
+}
+
+static u16 btf_type_vlen(const struct btf_type *t)
+{
+ return BTF_INFO_VLEN(t->info);
+}
+
+static u32 btf_type_int(const struct btf_type *t)
+{
+ return *(u32 *)(t + 1);
+}
+
+static const struct btf_array *btf_type_array(const struct btf_type *t)
+{
+ return (const struct btf_array *)(t + 1);
+}
+
+static const struct btf_member *btf_type_member(const struct btf_type *t)
+{
+ return (const struct btf_member *)(t + 1);
+}
+
+static const struct btf_enum *btf_type_enum(const struct btf_type *t)
+{
+ return (const struct btf_enum *)(t + 1);
+}
+
+static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
+{
+ return kind_ops[BTF_INFO_KIND(t->info)];
+}
+
+static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
+{
+ return BTF_STR_OFFSET_VALID(offset) &&
+ offset < btf->hdr.str_len;
+}
+
+static const char *btf_name_by_offset(const struct btf *btf, u32 offset)
+{
+ if (!offset)
+ return "(anon)";
+ else if (offset < btf->hdr.str_len)
+ return &btf->strings[offset];
+ else
+ return "(invalid-name-offset)";
+}
+
+static const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
+{
+ if (type_id > btf->nr_types)
+ return NULL;
+
+ return btf->types[type_id];
+}
+
+/*
+ * Regular int is not a bit field and it must be either
+ * u8/u16/u32/u64.
+ */
+static bool btf_type_int_is_regular(const struct btf_type *t)
+{
+ u8 nr_bits, nr_bytes;
+ u32 int_data;
+
+ int_data = btf_type_int(t);
+ nr_bits = BTF_INT_BITS(int_data);
+ nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
+ if (BITS_PER_BYTE_MASKED(nr_bits) ||
+ BTF_INT_OFFSET(int_data) ||
+ (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
+ nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64))) {
+ return false;
+ }
+
+ return true;
+}
+
+__printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
+ const char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ bpf_verifier_vlog(log, fmt, args);
+ va_end(args);
+}
+
+__printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
+ const char *fmt, ...)
+{
+ struct bpf_verifier_log *log = &env->log;
+ va_list args;
+
+ if (!bpf_verifier_log_needed(log))
+ return;
+
+ va_start(args, fmt);
+ bpf_verifier_vlog(log, fmt, args);
+ va_end(args);
+}
+
+__printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ bool log_details,
+ const char *fmt, ...)
+{
+ struct bpf_verifier_log *log = &env->log;
+ u8 kind = BTF_INFO_KIND(t->info);
+ struct btf *btf = env->btf;
+ va_list args;
+
+ if (!bpf_verifier_log_needed(log))
+ return;
+
+ __btf_verifier_log(log, "[%u] %s %s%s",
+ env->log_type_id,
+ btf_kind_str[kind],
+ btf_name_by_offset(btf, t->name_off),
+ log_details ? " " : "");
+
+ if (log_details)
+ btf_type_ops(t)->log_details(env, t);
+
+ if (fmt && *fmt) {
+ __btf_verifier_log(log, " ");
+ va_start(args, fmt);
+ bpf_verifier_vlog(log, fmt, args);
+ va_end(args);
+ }
+
+ __btf_verifier_log(log, "\n");
+}
+
+#define btf_verifier_log_type(env, t, ...) \
+ __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
+#define btf_verifier_log_basic(env, t, ...) \
+ __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
+
+__printf(4, 5)
+static void btf_verifier_log_member(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const char *fmt, ...)
+{
+ struct bpf_verifier_log *log = &env->log;
+ struct btf *btf = env->btf;
+ va_list args;
+
+ if (!bpf_verifier_log_needed(log))
+ return;
+
+ /* The CHECK_META phase already did a btf dump.
+ *
+ * If member is logged again, it must hit an error in
+ * parsing this member. It is useful to print out which
+ * struct this member belongs to.
+ */
+ if (env->phase != CHECK_META)
+ btf_verifier_log_type(env, struct_type, NULL);
+
+ __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
+ btf_name_by_offset(btf, member->name_off),
+ member->type, member->offset);
+
+ if (fmt && *fmt) {
+ __btf_verifier_log(log, " ");
+ va_start(args, fmt);
+ bpf_verifier_vlog(log, fmt, args);
+ va_end(args);
+ }
+
+ __btf_verifier_log(log, "\n");
+}
+
+static void btf_verifier_log_hdr(struct btf_verifier_env *env,
+ u32 btf_data_size)
+{
+ struct bpf_verifier_log *log = &env->log;
+ const struct btf *btf = env->btf;
+ const struct btf_header *hdr;
+
+ if (!bpf_verifier_log_needed(log))
+ return;
+
+ hdr = &btf->hdr;
+ __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
+ __btf_verifier_log(log, "version: %u\n", hdr->version);
+ __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
+ __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
+ __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
+ __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
+ __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
+ __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
+ __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
+}
+
+static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
+{
+ struct btf *btf = env->btf;
+
+ /* < 2 because +1 for btf_void which is always in btf->types[0].
+ * btf_void is not accounted in btf->nr_types because btf_void
+ * does not come from the BTF file.
+ */
+ if (btf->types_size - btf->nr_types < 2) {
+ /* Expand 'types' array */
+
+ struct btf_type **new_types;
+ u32 expand_by, new_size;
+
+ if (btf->types_size == BTF_MAX_TYPE) {
+ btf_verifier_log(env, "Exceeded max num of types");
+ return -E2BIG;
+ }
+
+ expand_by = max_t(u32, btf->types_size >> 2, 16);
+ new_size = min_t(u32, BTF_MAX_TYPE,
+ btf->types_size + expand_by);
+
+ new_types = kvcalloc(new_size, sizeof(*new_types),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!new_types)
+ return -ENOMEM;
+
+ if (btf->nr_types == 0)
+ new_types[0] = &btf_void;
+ else
+ memcpy(new_types, btf->types,
+ sizeof(*btf->types) * (btf->nr_types + 1));
+
+ kvfree(btf->types);
+ btf->types = new_types;
+ btf->types_size = new_size;
+ }
+
+ btf->types[++(btf->nr_types)] = t;
+
+ return 0;
+}
+
+static int btf_alloc_id(struct btf *btf)
+{
+ int id;
+
+ idr_preload(GFP_KERNEL);
+ spin_lock_bh(&btf_idr_lock);
+ id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
+ if (id > 0)
+ btf->id = id;
+ spin_unlock_bh(&btf_idr_lock);
+ idr_preload_end();
+
+ if (WARN_ON_ONCE(!id))
+ return -ENOSPC;
+
+ return id > 0 ? 0 : id;
+}
+
+static void btf_free_id(struct btf *btf)
+{
+ unsigned long flags;
+
+ /*
+ * In map-in-map, calling map_delete_elem() on outer
+ * map will call bpf_map_put on the inner map.
+ * It will then eventually call btf_free_id()
+ * on the inner map. Some of the map_delete_elem()
+ * implementation may have irq disabled, so
+ * we need to use the _irqsave() version instead
+ * of the _bh() version.
+ */
+ spin_lock_irqsave(&btf_idr_lock, flags);
+ idr_remove(&btf_idr, btf->id);
+ spin_unlock_irqrestore(&btf_idr_lock, flags);
+}
+
+static void btf_free(struct btf *btf)
+{
+ kvfree(btf->types);
+ kvfree(btf->resolved_sizes);
+ kvfree(btf->resolved_ids);
+ kvfree(btf->data);
+ kfree(btf);
+}
+
+static void btf_free_rcu(struct rcu_head *rcu)
+{
+ struct btf *btf = container_of(rcu, struct btf, rcu);
+
+ btf_free(btf);
+}
+
+void btf_put(struct btf *btf)
+{
+ if (btf && refcount_dec_and_test(&btf->refcnt)) {
+ btf_free_id(btf);
+ call_rcu(&btf->rcu, btf_free_rcu);
+ }
+}
+
+static int env_resolve_init(struct btf_verifier_env *env)
+{
+ struct btf *btf = env->btf;
+ u32 nr_types = btf->nr_types;
+ u32 *resolved_sizes = NULL;
+ u32 *resolved_ids = NULL;
+ u8 *visit_states = NULL;
+
+ /* +1 for btf_void */
+ resolved_sizes = kvcalloc(nr_types + 1, sizeof(*resolved_sizes),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!resolved_sizes)
+ goto nomem;
+
+ resolved_ids = kvcalloc(nr_types + 1, sizeof(*resolved_ids),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!resolved_ids)
+ goto nomem;
+
+ visit_states = kvcalloc(nr_types + 1, sizeof(*visit_states),
+ GFP_KERNEL | __GFP_NOWARN);
+ if (!visit_states)
+ goto nomem;
+
+ btf->resolved_sizes = resolved_sizes;
+ btf->resolved_ids = resolved_ids;
+ env->visit_states = visit_states;
+
+ return 0;
+
+nomem:
+ kvfree(resolved_sizes);
+ kvfree(resolved_ids);
+ kvfree(visit_states);
+ return -ENOMEM;
+}
+
+static void btf_verifier_env_free(struct btf_verifier_env *env)
+{
+ kvfree(env->visit_states);
+ kfree(env);
+}
+
+static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
+ const struct btf_type *next_type)
+{
+ switch (env->resolve_mode) {
+ case RESOLVE_TBD:
+ /* int, enum or void is a sink */
+ return !btf_type_needs_resolve(next_type);
+ case RESOLVE_PTR:
+ /* int, enum, void, struct or array is a sink for ptr */
+ return !btf_type_is_modifier(next_type) &&
+ !btf_type_is_ptr(next_type);
+ case RESOLVE_STRUCT_OR_ARRAY:
+ /* int, enum, void or ptr is a sink for struct and array */
+ return !btf_type_is_modifier(next_type) &&
+ !btf_type_is_array(next_type) &&
+ !btf_type_is_struct(next_type);
+ default:
+ BUG();
+ }
+}
+
+static bool env_type_is_resolved(const struct btf_verifier_env *env,
+ u32 type_id)
+{
+ return env->visit_states[type_id] == RESOLVED;
+}
+
+static int env_stack_push(struct btf_verifier_env *env,
+ const struct btf_type *t, u32 type_id)
+{
+ struct resolve_vertex *v;
+
+ if (env->top_stack == MAX_RESOLVE_DEPTH)
+ return -E2BIG;
+
+ if (env->visit_states[type_id] != NOT_VISITED)
+ return -EEXIST;
+
+ env->visit_states[type_id] = VISITED;
+
+ v = &env->stack[env->top_stack++];
+ v->t = t;
+ v->type_id = type_id;
+ v->next_member = 0;
+
+ if (env->resolve_mode == RESOLVE_TBD) {
+ if (btf_type_is_ptr(t))
+ env->resolve_mode = RESOLVE_PTR;
+ else if (btf_type_is_struct(t) || btf_type_is_array(t))
+ env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
+ }
+
+ return 0;
+}
+
+static void env_stack_set_next_member(struct btf_verifier_env *env,
+ u16 next_member)
+{
+ env->stack[env->top_stack - 1].next_member = next_member;
+}
+
+static void env_stack_pop_resolved(struct btf_verifier_env *env,
+ u32 resolved_type_id,
+ u32 resolved_size)
+{
+ u32 type_id = env->stack[--(env->top_stack)].type_id;
+ struct btf *btf = env->btf;
+
+ btf->resolved_sizes[type_id] = resolved_size;
+ btf->resolved_ids[type_id] = resolved_type_id;
+ env->visit_states[type_id] = RESOLVED;
+}
+
+static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
+{
+ return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
+}
+
+/* The input param "type_id" must point to a needs_resolve type */
+static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
+ u32 *type_id)
+{
+ *type_id = btf->resolved_ids[*type_id];
+ return btf_type_by_id(btf, *type_id);
+}
+
+const struct btf_type *btf_type_id_size(const struct btf *btf,
+ u32 *type_id, u32 *ret_size)
+{
+ const struct btf_type *size_type;
+ u32 size_type_id = *type_id;
+ u32 size = 0;
+
+ size_type = btf_type_by_id(btf, size_type_id);
+ if (btf_type_is_void_or_null(size_type))
+ return NULL;
+
+ if (btf_type_has_size(size_type)) {
+ size = size_type->size;
+ } else if (btf_type_is_array(size_type)) {
+ size = btf->resolved_sizes[size_type_id];
+ } else if (btf_type_is_ptr(size_type)) {
+ size = sizeof(void *);
+ } else {
+ if (WARN_ON_ONCE(!btf_type_is_modifier(size_type)))
+ return NULL;
+
+ size = btf->resolved_sizes[size_type_id];
+ size_type_id = btf->resolved_ids[size_type_id];
+ size_type = btf_type_by_id(btf, size_type_id);
+ if (btf_type_is_void(size_type))
+ return NULL;
+ }
+
+ *type_id = size_type_id;
+ if (ret_size)
+ *ret_size = size;
+
+ return size_type;
+}
+
+static int btf_df_check_member(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const struct btf_type *member_type)
+{
+ btf_verifier_log_basic(env, struct_type,
+ "Unsupported check_member");
+ return -EINVAL;
+}
+
+static int btf_df_resolve(struct btf_verifier_env *env,
+ const struct resolve_vertex *v)
+{
+ btf_verifier_log_basic(env, v->t, "Unsupported resolve");
+ return -EINVAL;
+}
+
+static void btf_df_seq_show(const struct btf *btf, const struct btf_type *t,
+ u32 type_id, void *data, u8 bits_offsets,
+ struct seq_file *m)
+{
+ seq_printf(m, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
+}
+
+static int btf_int_check_member(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const struct btf_type *member_type)
+{
+ u32 int_data = btf_type_int(member_type);
+ u32 struct_bits_off = member->offset;
+ u32 struct_size = struct_type->size;
+ u32 nr_copy_bits;
+ u32 bytes_offset;
+
+ if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
+ btf_verifier_log_member(env, struct_type, member,
+ "bits_offset exceeds U32_MAX");
+ return -EINVAL;
+ }
+
+ struct_bits_off += BTF_INT_OFFSET(int_data);
+ bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+ nr_copy_bits = BTF_INT_BITS(int_data) +
+ BITS_PER_BYTE_MASKED(struct_bits_off);
+
+ if (nr_copy_bits > BITS_PER_U64) {
+ btf_verifier_log_member(env, struct_type, member,
+ "nr_copy_bits exceeds 64");
+ return -EINVAL;
+ }
+
+ if (struct_size < bytes_offset ||
+ struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member exceeds struct_size");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static s32 btf_int_check_meta(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 meta_left)
+{
+ u32 int_data, nr_bits, meta_needed = sizeof(int_data);
+ u16 encoding;
+
+ if (meta_left < meta_needed) {
+ btf_verifier_log_basic(env, t,
+ "meta_left:%u meta_needed:%u",
+ meta_left, meta_needed);
+ return -EINVAL;
+ }
+
+ if (btf_type_vlen(t)) {
+ btf_verifier_log_type(env, t, "vlen != 0");
+ return -EINVAL;
+ }
+
+ int_data = btf_type_int(t);
+ if (int_data & ~BTF_INT_MASK) {
+ btf_verifier_log_basic(env, t, "Invalid int_data:%x",
+ int_data);
+ return -EINVAL;
+ }
+
+ nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
+
+ if (nr_bits > BITS_PER_U64) {
+ btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
+ BITS_PER_U64);
+ return -EINVAL;
+ }
+
+ if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
+ btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
+ return -EINVAL;
+ }
+
+ /*
+ * Only one of the encoding bits is allowed and it
+ * should be sufficient for the pretty print purpose (i.e. decoding).
+ * Multiple bits can be allowed later if it is found
+ * to be insufficient.
+ */
+ encoding = BTF_INT_ENCODING(int_data);
+ if (encoding &&
+ encoding != BTF_INT_SIGNED &&
+ encoding != BTF_INT_CHAR &&
+ encoding != BTF_INT_BOOL) {
+ btf_verifier_log_type(env, t, "Unsupported encoding");
+ return -ENOTSUPP;
+ }
+
+ btf_verifier_log_type(env, t, NULL);
+
+ return meta_needed;
+}
+
+static void btf_int_log(struct btf_verifier_env *env,
+ const struct btf_type *t)
+{
+ int int_data = btf_type_int(t);
+
+ btf_verifier_log(env,
+ "size=%u bits_offset=%u nr_bits=%u encoding=%s",
+ t->size, BTF_INT_OFFSET(int_data),
+ BTF_INT_BITS(int_data),
+ btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
+}
+
+static void btf_int_bits_seq_show(const struct btf *btf,
+ const struct btf_type *t,
+ void *data, u8 bits_offset,
+ struct seq_file *m)
+{
+ u16 left_shift_bits, right_shift_bits;
+ u32 int_data = btf_type_int(t);
+ u8 nr_bits = BTF_INT_BITS(int_data);
+ u8 total_bits_offset;
+ u8 nr_copy_bytes;
+ u8 nr_copy_bits;
+ u64 print_num;
+
+ /*
+ * bits_offset is at most 7.
+ * BTF_INT_OFFSET() cannot exceed 64 bits.
+ */
+ total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
+ data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
+ bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
+ nr_copy_bits = nr_bits + bits_offset;
+ nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
+
+ print_num = 0;
+ memcpy(&print_num, data, nr_copy_bytes);
+
+#ifdef __BIG_ENDIAN_BITFIELD
+ left_shift_bits = bits_offset;
+#else
+ left_shift_bits = BITS_PER_U64 - nr_copy_bits;
+#endif
+ right_shift_bits = BITS_PER_U64 - nr_bits;
+
+ print_num <<= left_shift_bits;
+ print_num >>= right_shift_bits;
+
+ seq_printf(m, "0x%llx", print_num);
+}
+
+static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t,
+ u32 type_id, void *data, u8 bits_offset,
+ struct seq_file *m)
+{
+ u32 int_data = btf_type_int(t);
+ u8 encoding = BTF_INT_ENCODING(int_data);
+ bool sign = encoding & BTF_INT_SIGNED;
+ u8 nr_bits = BTF_INT_BITS(int_data);
+
+ if (bits_offset || BTF_INT_OFFSET(int_data) ||
+ BITS_PER_BYTE_MASKED(nr_bits)) {
+ btf_int_bits_seq_show(btf, t, data, bits_offset, m);
+ return;
+ }
+
+ switch (nr_bits) {
+ case 64:
+ if (sign)
+ seq_printf(m, "%lld", *(s64 *)data);
+ else
+ seq_printf(m, "%llu", *(u64 *)data);
+ break;
+ case 32:
+ if (sign)
+ seq_printf(m, "%d", *(s32 *)data);
+ else
+ seq_printf(m, "%u", *(u32 *)data);
+ break;
+ case 16:
+ if (sign)
+ seq_printf(m, "%d", *(s16 *)data);
+ else
+ seq_printf(m, "%u", *(u16 *)data);
+ break;
+ case 8:
+ if (sign)
+ seq_printf(m, "%d", *(s8 *)data);
+ else
+ seq_printf(m, "%u", *(u8 *)data);
+ break;
+ default:
+ btf_int_bits_seq_show(btf, t, data, bits_offset, m);
+ }
+}
+
+static const struct btf_kind_operations int_ops = {
+ .check_meta = btf_int_check_meta,
+ .resolve = btf_df_resolve,
+ .check_member = btf_int_check_member,
+ .log_details = btf_int_log,
+ .seq_show = btf_int_seq_show,
+};
+
+static int btf_modifier_check_member(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const struct btf_type *member_type)
+{
+ const struct btf_type *resolved_type;
+ u32 resolved_type_id = member->type;
+ struct btf_member resolved_member;
+ struct btf *btf = env->btf;
+
+ resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
+ if (!resolved_type) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Invalid member");
+ return -EINVAL;
+ }
+
+ resolved_member = *member;
+ resolved_member.type = resolved_type_id;
+
+ return btf_type_ops(resolved_type)->check_member(env, struct_type,
+ &resolved_member,
+ resolved_type);
+}
+
+static int btf_ptr_check_member(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const struct btf_type *member_type)
+{
+ u32 struct_size, struct_bits_off, bytes_offset;
+
+ struct_size = struct_type->size;
+ struct_bits_off = member->offset;
+ bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+
+ if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member is not byte aligned");
+ return -EINVAL;
+ }
+
+ if (struct_size - bytes_offset < sizeof(void *)) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member exceeds struct_size");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int btf_ref_type_check_meta(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 meta_left)
+{
+ if (btf_type_vlen(t)) {
+ btf_verifier_log_type(env, t, "vlen != 0");
+ return -EINVAL;
+ }
+
+ if (!BTF_TYPE_ID_VALID(t->type)) {
+ btf_verifier_log_type(env, t, "Invalid type_id");
+ return -EINVAL;
+ }
+
+ btf_verifier_log_type(env, t, NULL);
+
+ return 0;
+}
+
+static int btf_modifier_resolve(struct btf_verifier_env *env,
+ const struct resolve_vertex *v)
+{
+ const struct btf_type *t = v->t;
+ const struct btf_type *next_type;
+ u32 next_type_id = t->type;
+ struct btf *btf = env->btf;
+ u32 next_type_size = 0;
+
+ next_type = btf_type_by_id(btf, next_type_id);
+ if (!next_type) {
+ btf_verifier_log_type(env, v->t, "Invalid type_id");
+ return -EINVAL;
+ }
+
+ /* "typedef void new_void", "const void"...etc */
+ if (btf_type_is_void(next_type))
+ goto resolved;
+
+ if (!env_type_is_resolve_sink(env, next_type) &&
+ !env_type_is_resolved(env, next_type_id))
+ return env_stack_push(env, next_type, next_type_id);
+
+ /* Figure out the resolved next_type_id with size.
+ * They will be stored in the current modifier's
+ * resolved_ids and resolved_sizes such that it can
+ * save us a few type-following when we use it later (e.g. in
+ * pretty print).
+ */
+ if (!btf_type_id_size(btf, &next_type_id, &next_type_size) &&
+ !btf_type_is_void(btf_type_id_resolve(btf, &next_type_id))) {
+ btf_verifier_log_type(env, v->t, "Invalid type_id");
+ return -EINVAL;
+ }
+
+resolved:
+ env_stack_pop_resolved(env, next_type_id, next_type_size);
+
+ return 0;
+}
+
+static int btf_ptr_resolve(struct btf_verifier_env *env,
+ const struct resolve_vertex *v)
+{
+ const struct btf_type *next_type;
+ const struct btf_type *t = v->t;
+ u32 next_type_id = t->type;
+ struct btf *btf = env->btf;
+ u32 next_type_size = 0;
+
+ next_type = btf_type_by_id(btf, next_type_id);
+ if (!next_type) {
+ btf_verifier_log_type(env, v->t, "Invalid type_id");
+ return -EINVAL;
+ }
+
+ /* "void *" */
+ if (btf_type_is_void(next_type))
+ goto resolved;
+
+ if (!env_type_is_resolve_sink(env, next_type) &&
+ !env_type_is_resolved(env, next_type_id))
+ return env_stack_push(env, next_type, next_type_id);
+
+ /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
+ * the modifier may have stopped resolving when it was resolved
+ * to a ptr (last-resolved-ptr).
+ *
+ * We now need to continue from the last-resolved-ptr to
+ * ensure the last-resolved-ptr will not referring back to
+ * the currenct ptr (t).
+ */
+ if (btf_type_is_modifier(next_type)) {
+ const struct btf_type *resolved_type;
+ u32 resolved_type_id;
+
+ resolved_type_id = next_type_id;
+ resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
+
+ if (btf_type_is_ptr(resolved_type) &&
+ !env_type_is_resolve_sink(env, resolved_type) &&
+ !env_type_is_resolved(env, resolved_type_id))
+ return env_stack_push(env, resolved_type,
+ resolved_type_id);
+ }
+
+ if (!btf_type_id_size(btf, &next_type_id, &next_type_size) &&
+ !btf_type_is_void(btf_type_id_resolve(btf, &next_type_id))) {
+ btf_verifier_log_type(env, v->t, "Invalid type_id");
+ return -EINVAL;
+ }
+
+resolved:
+ env_stack_pop_resolved(env, next_type_id, 0);
+
+ return 0;
+}
+
+static void btf_modifier_seq_show(const struct btf *btf,
+ const struct btf_type *t,
+ u32 type_id, void *data,
+ u8 bits_offset, struct seq_file *m)
+{
+ t = btf_type_id_resolve(btf, &type_id);
+
+ btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
+}
+
+static void btf_ptr_seq_show(const struct btf *btf, const struct btf_type *t,
+ u32 type_id, void *data, u8 bits_offset,
+ struct seq_file *m)
+{
+ /* It is a hashed value */
+ seq_printf(m, "%p", *(void **)data);
+}
+
+static void btf_ref_type_log(struct btf_verifier_env *env,
+ const struct btf_type *t)
+{
+ btf_verifier_log(env, "type_id=%u", t->type);
+}
+
+static struct btf_kind_operations modifier_ops = {
+ .check_meta = btf_ref_type_check_meta,
+ .resolve = btf_modifier_resolve,
+ .check_member = btf_modifier_check_member,
+ .log_details = btf_ref_type_log,
+ .seq_show = btf_modifier_seq_show,
+};
+
+static struct btf_kind_operations ptr_ops = {
+ .check_meta = btf_ref_type_check_meta,
+ .resolve = btf_ptr_resolve,
+ .check_member = btf_ptr_check_member,
+ .log_details = btf_ref_type_log,
+ .seq_show = btf_ptr_seq_show,
+};
+
+static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 meta_left)
+{
+ if (btf_type_vlen(t)) {
+ btf_verifier_log_type(env, t, "vlen != 0");
+ return -EINVAL;
+ }
+
+ if (t->type) {
+ btf_verifier_log_type(env, t, "type != 0");
+ return -EINVAL;
+ }
+
+ btf_verifier_log_type(env, t, NULL);
+
+ return 0;
+}
+
+static struct btf_kind_operations fwd_ops = {
+ .check_meta = btf_fwd_check_meta,
+ .resolve = btf_df_resolve,
+ .check_member = btf_df_check_member,
+ .log_details = btf_ref_type_log,
+ .seq_show = btf_df_seq_show,
+};
+
+static int btf_array_check_member(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const struct btf_type *member_type)
+{
+ u32 struct_bits_off = member->offset;
+ u32 struct_size, bytes_offset;
+ u32 array_type_id, array_size;
+ struct btf *btf = env->btf;
+
+ if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member is not byte aligned");
+ return -EINVAL;
+ }
+
+ array_type_id = member->type;
+ btf_type_id_size(btf, &array_type_id, &array_size);
+ struct_size = struct_type->size;
+ bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+ if (struct_size - bytes_offset < array_size) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member exceeds struct_size");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static s32 btf_array_check_meta(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 meta_left)
+{
+ const struct btf_array *array = btf_type_array(t);
+ u32 meta_needed = sizeof(*array);
+
+ if (meta_left < meta_needed) {
+ btf_verifier_log_basic(env, t,
+ "meta_left:%u meta_needed:%u",
+ meta_left, meta_needed);
+ return -EINVAL;
+ }
+
+ if (btf_type_vlen(t)) {
+ btf_verifier_log_type(env, t, "vlen != 0");
+ return -EINVAL;
+ }
+
+ if (t->size) {
+ btf_verifier_log_type(env, t, "size != 0");
+ return -EINVAL;
+ }
+
+ /* Array elem type and index type cannot be in type void,
+ * so !array->type and !array->index_type are not allowed.
+ */
+ if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
+ btf_verifier_log_type(env, t, "Invalid elem");
+ return -EINVAL;
+ }
+
+ if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
+ btf_verifier_log_type(env, t, "Invalid index");
+ return -EINVAL;
+ }
+
+ btf_verifier_log_type(env, t, NULL);
+
+ return meta_needed;
+}
+
+static int btf_array_resolve(struct btf_verifier_env *env,
+ const struct resolve_vertex *v)
+{
+ const struct btf_array *array = btf_type_array(v->t);
+ const struct btf_type *elem_type, *index_type;
+ u32 elem_type_id, index_type_id;
+ struct btf *btf = env->btf;
+ u32 elem_size;
+
+ /* Check array->index_type */
+ index_type_id = array->index_type;
+ index_type = btf_type_by_id(btf, index_type_id);
+ if (btf_type_is_void_or_null(index_type)) {
+ btf_verifier_log_type(env, v->t, "Invalid index");
+ return -EINVAL;
+ }
+
+ if (!env_type_is_resolve_sink(env, index_type) &&
+ !env_type_is_resolved(env, index_type_id))
+ return env_stack_push(env, index_type, index_type_id);
+
+ index_type = btf_type_id_size(btf, &index_type_id, NULL);
+ if (!index_type || !btf_type_is_int(index_type) ||
+ !btf_type_int_is_regular(index_type)) {
+ btf_verifier_log_type(env, v->t, "Invalid index");
+ return -EINVAL;
+ }
+
+ /* Check array->type */
+ elem_type_id = array->type;
+ elem_type = btf_type_by_id(btf, elem_type_id);
+ if (btf_type_is_void_or_null(elem_type)) {
+ btf_verifier_log_type(env, v->t,
+ "Invalid elem");
+ return -EINVAL;
+ }
+
+ if (!env_type_is_resolve_sink(env, elem_type) &&
+ !env_type_is_resolved(env, elem_type_id))
+ return env_stack_push(env, elem_type, elem_type_id);
+
+ elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
+ if (!elem_type) {
+ btf_verifier_log_type(env, v->t, "Invalid elem");
+ return -EINVAL;
+ }
+
+ if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
+ btf_verifier_log_type(env, v->t, "Invalid array of int");
+ return -EINVAL;
+ }
+
+ if (array->nelems && elem_size > U32_MAX / array->nelems) {
+ btf_verifier_log_type(env, v->t,
+ "Array size overflows U32_MAX");
+ return -EINVAL;
+ }
+
+ env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
+
+ return 0;
+}
+
+static void btf_array_log(struct btf_verifier_env *env,
+ const struct btf_type *t)
+{
+ const struct btf_array *array = btf_type_array(t);
+
+ btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
+ array->type, array->index_type, array->nelems);
+}
+
+static void btf_array_seq_show(const struct btf *btf, const struct btf_type *t,
+ u32 type_id, void *data, u8 bits_offset,
+ struct seq_file *m)
+{
+ const struct btf_array *array = btf_type_array(t);
+ const struct btf_kind_operations *elem_ops;
+ const struct btf_type *elem_type;
+ u32 i, elem_size, elem_type_id;
+
+ elem_type_id = array->type;
+ elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
+ elem_ops = btf_type_ops(elem_type);
+ seq_puts(m, "[");
+ for (i = 0; i < array->nelems; i++) {
+ if (i)
+ seq_puts(m, ",");
+
+ elem_ops->seq_show(btf, elem_type, elem_type_id, data,
+ bits_offset, m);
+ data += elem_size;
+ }
+ seq_puts(m, "]");
+}
+
+static struct btf_kind_operations array_ops = {
+ .check_meta = btf_array_check_meta,
+ .resolve = btf_array_resolve,
+ .check_member = btf_array_check_member,
+ .log_details = btf_array_log,
+ .seq_show = btf_array_seq_show,
+};
+
+static int btf_struct_check_member(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const struct btf_type *member_type)
+{
+ u32 struct_bits_off = member->offset;
+ u32 struct_size, bytes_offset;
+
+ if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member is not byte aligned");
+ return -EINVAL;
+ }
+
+ struct_size = struct_type->size;
+ bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+ if (struct_size - bytes_offset < member_type->size) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member exceeds struct_size");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static s32 btf_struct_check_meta(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 meta_left)
+{
+ bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
+ const struct btf_member *member;
+ u32 meta_needed, last_offset;
+ struct btf *btf = env->btf;
+ u32 struct_size = t->size;
+ u16 i;
+
+ meta_needed = btf_type_vlen(t) * sizeof(*member);
+ if (meta_left < meta_needed) {
+ btf_verifier_log_basic(env, t,
+ "meta_left:%u meta_needed:%u",
+ meta_left, meta_needed);
+ return -EINVAL;
+ }
+
+ btf_verifier_log_type(env, t, NULL);
+
+ last_offset = 0;
+ for_each_member(i, t, member) {
+ if (!btf_name_offset_valid(btf, member->name_off)) {
+ btf_verifier_log_member(env, t, member,
+ "Invalid member name_offset:%u",
+ member->name_off);
+ return -EINVAL;
+ }
+
+ /* A member cannot be in type void */
+ if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
+ btf_verifier_log_member(env, t, member,
+ "Invalid type_id");
+ return -EINVAL;
+ }
+
+ if (is_union && member->offset) {
+ btf_verifier_log_member(env, t, member,
+ "Invalid member bits_offset");
+ return -EINVAL;
+ }
+
+ /*
+ * ">" instead of ">=" because the last member could be
+ * "char a[0];"
+ */
+ if (last_offset > member->offset) {
+ btf_verifier_log_member(env, t, member,
+ "Invalid member bits_offset");
+ return -EINVAL;
+ }
+
+ if (BITS_ROUNDUP_BYTES(member->offset) > struct_size) {
+ btf_verifier_log_member(env, t, member,
+ "Memmber bits_offset exceeds its struct size");
+ return -EINVAL;
+ }
+
+ btf_verifier_log_member(env, t, member, NULL);
+ last_offset = member->offset;
+ }
+
+ return meta_needed;
+}
+
+static int btf_struct_resolve(struct btf_verifier_env *env,
+ const struct resolve_vertex *v)
+{
+ const struct btf_member *member;
+ int err;
+ u16 i;
+
+ /* Before continue resolving the next_member,
+ * ensure the last member is indeed resolved to a
+ * type with size info.
+ */
+ if (v->next_member) {
+ const struct btf_type *last_member_type;
+ const struct btf_member *last_member;
+ u16 last_member_type_id;
+
+ last_member = btf_type_member(v->t) + v->next_member - 1;
+ last_member_type_id = last_member->type;
+ if (WARN_ON_ONCE(!env_type_is_resolved(env,
+ last_member_type_id)))
+ return -EINVAL;
+
+ last_member_type = btf_type_by_id(env->btf,
+ last_member_type_id);
+ err = btf_type_ops(last_member_type)->check_member(env, v->t,
+ last_member,
+ last_member_type);
+ if (err)
+ return err;
+ }
+
+ for_each_member_from(i, v->next_member, v->t, member) {
+ u32 member_type_id = member->type;
+ const struct btf_type *member_type = btf_type_by_id(env->btf,
+ member_type_id);
+
+ if (btf_type_is_void_or_null(member_type)) {
+ btf_verifier_log_member(env, v->t, member,
+ "Invalid member");
+ return -EINVAL;
+ }
+
+ if (!env_type_is_resolve_sink(env, member_type) &&
+ !env_type_is_resolved(env, member_type_id)) {
+ env_stack_set_next_member(env, i + 1);
+ return env_stack_push(env, member_type, member_type_id);
+ }
+
+ err = btf_type_ops(member_type)->check_member(env, v->t,
+ member,
+ member_type);
+ if (err)
+ return err;
+ }
+
+ env_stack_pop_resolved(env, 0, 0);
+
+ return 0;
+}
+
+static void btf_struct_log(struct btf_verifier_env *env,
+ const struct btf_type *t)
+{
+ btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
+}
+
+static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t,
+ u32 type_id, void *data, u8 bits_offset,
+ struct seq_file *m)
+{
+ const char *seq = BTF_INFO_KIND(t->info) == BTF_KIND_UNION ? "|" : ",";
+ const struct btf_member *member;
+ u32 i;
+
+ seq_puts(m, "{");
+ for_each_member(i, t, member) {
+ const struct btf_type *member_type = btf_type_by_id(btf,
+ member->type);
+ u32 member_offset = member->offset;
+ u32 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
+ u8 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
+ const struct btf_kind_operations *ops;
+
+ if (i)
+ seq_puts(m, seq);
+
+ ops = btf_type_ops(member_type);
+ ops->seq_show(btf, member_type, member->type,
+ data + bytes_offset, bits8_offset, m);
+ }
+ seq_puts(m, "}");
+}
+
+static struct btf_kind_operations struct_ops = {
+ .check_meta = btf_struct_check_meta,
+ .resolve = btf_struct_resolve,
+ .check_member = btf_struct_check_member,
+ .log_details = btf_struct_log,
+ .seq_show = btf_struct_seq_show,
+};
+
+static int btf_enum_check_member(struct btf_verifier_env *env,
+ const struct btf_type *struct_type,
+ const struct btf_member *member,
+ const struct btf_type *member_type)
+{
+ u32 struct_bits_off = member->offset;
+ u32 struct_size, bytes_offset;
+
+ if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member is not byte aligned");
+ return -EINVAL;
+ }
+
+ struct_size = struct_type->size;
+ bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
+ if (struct_size - bytes_offset < sizeof(int)) {
+ btf_verifier_log_member(env, struct_type, member,
+ "Member exceeds struct_size");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static s32 btf_enum_check_meta(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 meta_left)
+{
+ const struct btf_enum *enums = btf_type_enum(t);
+ struct btf *btf = env->btf;
+ u16 i, nr_enums;
+ u32 meta_needed;
+
+ nr_enums = btf_type_vlen(t);
+ meta_needed = nr_enums * sizeof(*enums);
+
+ if (meta_left < meta_needed) {
+ btf_verifier_log_basic(env, t,
+ "meta_left:%u meta_needed:%u",
+ meta_left, meta_needed);
+ return -EINVAL;
+ }
+
+ if (t->size != sizeof(int)) {
+ btf_verifier_log_type(env, t, "Expected size:%zu",
+ sizeof(int));
+ return -EINVAL;
+ }
+
+ btf_verifier_log_type(env, t, NULL);
+
+ for (i = 0; i < nr_enums; i++) {
+ if (!btf_name_offset_valid(btf, enums[i].name_off)) {
+ btf_verifier_log(env, "\tInvalid name_offset:%u",
+ enums[i].name_off);
+ return -EINVAL;
+ }
+
+ btf_verifier_log(env, "\t%s val=%d\n",
+ btf_name_by_offset(btf, enums[i].name_off),
+ enums[i].val);
+ }
+
+ return meta_needed;
+}
+
+static void btf_enum_log(struct btf_verifier_env *env,
+ const struct btf_type *t)
+{
+ btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
+}
+
+static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t,
+ u32 type_id, void *data, u8 bits_offset,
+ struct seq_file *m)
+{
+ const struct btf_enum *enums = btf_type_enum(t);
+ u32 i, nr_enums = btf_type_vlen(t);
+ int v = *(int *)data;
+
+ for (i = 0; i < nr_enums; i++) {
+ if (v == enums[i].val) {
+ seq_printf(m, "%s",
+ btf_name_by_offset(btf, enums[i].name_off));
+ return;
+ }
+ }
+
+ seq_printf(m, "%d", v);
+}
+
+static struct btf_kind_operations enum_ops = {
+ .check_meta = btf_enum_check_meta,
+ .resolve = btf_df_resolve,
+ .check_member = btf_enum_check_member,
+ .log_details = btf_enum_log,
+ .seq_show = btf_enum_seq_show,
+};
+
+static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
+ [BTF_KIND_INT] = &int_ops,
+ [BTF_KIND_PTR] = &ptr_ops,
+ [BTF_KIND_ARRAY] = &array_ops,
+ [BTF_KIND_STRUCT] = &struct_ops,
+ [BTF_KIND_UNION] = &struct_ops,
+ [BTF_KIND_ENUM] = &enum_ops,
+ [BTF_KIND_FWD] = &fwd_ops,
+ [BTF_KIND_TYPEDEF] = &modifier_ops,
+ [BTF_KIND_VOLATILE] = &modifier_ops,
+ [BTF_KIND_CONST] = &modifier_ops,
+ [BTF_KIND_RESTRICT] = &modifier_ops,
+};
+
+static s32 btf_check_meta(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 meta_left)
+{
+ u32 saved_meta_left = meta_left;
+ s32 var_meta_size;
+
+ if (meta_left < sizeof(*t)) {
+ btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
+ env->log_type_id, meta_left, sizeof(*t));
+ return -EINVAL;
+ }
+ meta_left -= sizeof(*t);
+
+ if (t->info & ~BTF_INFO_MASK) {
+ btf_verifier_log(env, "[%u] Invalid btf_info:%x",
+ env->log_type_id, t->info);
+ return -EINVAL;
+ }
+
+ if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
+ BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
+ btf_verifier_log(env, "[%u] Invalid kind:%u",
+ env->log_type_id, BTF_INFO_KIND(t->info));
+ return -EINVAL;
+ }
+
+ if (!btf_name_offset_valid(env->btf, t->name_off)) {
+ btf_verifier_log(env, "[%u] Invalid name_offset:%u",
+ env->log_type_id, t->name_off);
+ return -EINVAL;
+ }
+
+ var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
+ if (var_meta_size < 0)
+ return var_meta_size;
+
+ meta_left -= var_meta_size;
+
+ return saved_meta_left - meta_left;
+}
+
+static int btf_check_all_metas(struct btf_verifier_env *env)
+{
+ struct btf *btf = env->btf;
+ struct btf_header *hdr;
+ void *cur, *end;
+
+ hdr = &btf->hdr;
+ cur = btf->nohdr_data + hdr->type_off;
+ end = cur + hdr->type_len;
+
+ env->log_type_id = 1;
+ while (cur < end) {
+ struct btf_type *t = cur;
+ s32 meta_size;
+
+ meta_size = btf_check_meta(env, t, end - cur);
+ if (meta_size < 0)
+ return meta_size;
+
+ btf_add_type(env, t);
+ cur += meta_size;
+ env->log_type_id++;
+ }
+
+ return 0;
+}
+
+static int btf_resolve(struct btf_verifier_env *env,
+ const struct btf_type *t, u32 type_id)
+{
+ const struct resolve_vertex *v;
+ int err = 0;
+
+ env->resolve_mode = RESOLVE_TBD;
+ env_stack_push(env, t, type_id);
+ while (!err && (v = env_stack_peak(env))) {
+ env->log_type_id = v->type_id;
+ err = btf_type_ops(v->t)->resolve(env, v);
+ }
+
+ env->log_type_id = type_id;
+ if (err == -E2BIG)
+ btf_verifier_log_type(env, t,
+ "Exceeded max resolving depth:%u",
+ MAX_RESOLVE_DEPTH);
+ else if (err == -EEXIST)
+ btf_verifier_log_type(env, t, "Loop detected");
+
+ return err;
+}
+
+static bool btf_resolve_valid(struct btf_verifier_env *env,
+ const struct btf_type *t,
+ u32 type_id)
+{
+ struct btf *btf = env->btf;
+
+ if (!env_type_is_resolved(env, type_id))
+ return false;
+
+ if (btf_type_is_struct(t))
+ return !btf->resolved_ids[type_id] &&
+ !btf->resolved_sizes[type_id];
+
+ if (btf_type_is_modifier(t) || btf_type_is_ptr(t)) {
+ t = btf_type_id_resolve(btf, &type_id);
+ return t && !btf_type_is_modifier(t);
+ }
+
+ if (btf_type_is_array(t)) {
+ const struct btf_array *array = btf_type_array(t);
+ const struct btf_type *elem_type;
+ u32 elem_type_id = array->type;
+ u32 elem_size;
+
+ elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
+ return elem_type && !btf_type_is_modifier(elem_type) &&
+ (array->nelems * elem_size ==
+ btf->resolved_sizes[type_id]);
+ }
+
+ return false;
+}
+
+static int btf_check_all_types(struct btf_verifier_env *env)
+{
+ struct btf *btf = env->btf;
+ u32 type_id;
+ int err;
+
+ err = env_resolve_init(env);
+ if (err)
+ return err;
+
+ env->phase++;
+ for (type_id = 1; type_id <= btf->nr_types; type_id++) {
+ const struct btf_type *t = btf_type_by_id(btf, type_id);
+
+ env->log_type_id = type_id;
+ if (btf_type_needs_resolve(t) &&
+ !env_type_is_resolved(env, type_id)) {
+ err = btf_resolve(env, t, type_id);
+ if (err)
+ return err;
+ }
+
+ if (btf_type_needs_resolve(t) &&
+ !btf_resolve_valid(env, t, type_id)) {
+ btf_verifier_log_type(env, t, "Invalid resolve state");
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int btf_parse_type_sec(struct btf_verifier_env *env)
+{
+ const struct btf_header *hdr = &env->btf->hdr;
+ int err;
+
+ /* Type section must align to 4 bytes */
+ if (hdr->type_off & (sizeof(u32) - 1)) {
+ btf_verifier_log(env, "Unaligned type_off");
+ return -EINVAL;
+ }
+
+ if (!hdr->type_len) {
+ btf_verifier_log(env, "No type found");
+ return -EINVAL;
+ }
+
+ err = btf_check_all_metas(env);
+ if (err)
+ return err;
+
+ return btf_check_all_types(env);
+}
+
+static int btf_parse_str_sec(struct btf_verifier_env *env)
+{
+ const struct btf_header *hdr;
+ struct btf *btf = env->btf;
+ const char *start, *end;
+
+ hdr = &btf->hdr;
+ start = btf->nohdr_data + hdr->str_off;
+ end = start + hdr->str_len;
+
+ if (end != btf->data + btf->data_size) {
+ btf_verifier_log(env, "String section is not at the end");
+ return -EINVAL;
+ }
+
+ if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
+ start[0] || end[-1]) {
+ btf_verifier_log(env, "Invalid string section");
+ return -EINVAL;
+ }
+
+ btf->strings = start;
+
+ return 0;
+}
+
+static const size_t btf_sec_info_offset[] = {
+ offsetof(struct btf_header, type_off),
+ offsetof(struct btf_header, str_off),
+};
+
+static int btf_sec_info_cmp(const void *a, const void *b)
+{
+ const struct btf_sec_info *x = a;
+ const struct btf_sec_info *y = b;
+
+ return (int)(x->off - y->off) ? : (int)(x->len - y->len);
+}
+
+static int btf_check_sec_info(struct btf_verifier_env *env,
+ u32 btf_data_size)
+{
+ struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
+ u32 total, expected_total, i;
+ const struct btf_header *hdr;
+ const struct btf *btf;
+
+ btf = env->btf;
+ hdr = &btf->hdr;
+
+ /* Populate the secs from hdr */
+ for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
+ secs[i] = *(struct btf_sec_info *)((void *)hdr +
+ btf_sec_info_offset[i]);
+
+ sort(secs, ARRAY_SIZE(btf_sec_info_offset),
+ sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
+
+ /* Check for gaps and overlap among sections */
+ total = 0;
+ expected_total = btf_data_size - hdr->hdr_len;
+ for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
+ if (expected_total < secs[i].off) {
+ btf_verifier_log(env, "Invalid section offset");
+ return -EINVAL;
+ }
+ if (total < secs[i].off) {
+ /* gap */
+ btf_verifier_log(env, "Unsupported section found");
+ return -EINVAL;
+ }
+ if (total > secs[i].off) {
+ btf_verifier_log(env, "Section overlap found");
+ return -EINVAL;
+ }
+ if (expected_total - total < secs[i].len) {
+ btf_verifier_log(env,
+ "Total section length too long");
+ return -EINVAL;
+ }
+ total += secs[i].len;
+ }
+
+ /* There is data other than hdr and known sections */
+ if (expected_total != total) {
+ btf_verifier_log(env, "Unsupported section found");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int btf_parse_hdr(struct btf_verifier_env *env, void __user *btf_data,
+ u32 btf_data_size)
+{
+ const struct btf_header *hdr;
+ u32 hdr_len, hdr_copy;
+ /*
+ * Minimal part of the "struct btf_header" that
+ * contains the hdr_len.
+ */
+ struct btf_min_header {
+ u16 magic;
+ u8 version;
+ u8 flags;
+ u32 hdr_len;
+ } __user *min_hdr;
+ struct btf *btf;
+ int err;
+
+ btf = env->btf;
+ min_hdr = btf_data;
+
+ if (btf_data_size < sizeof(*min_hdr)) {
+ btf_verifier_log(env, "hdr_len not found");
+ return -EINVAL;
+ }
+
+ if (get_user(hdr_len, &min_hdr->hdr_len))
+ return -EFAULT;
+
+ if (btf_data_size < hdr_len) {
+ btf_verifier_log(env, "btf_header not found");
+ return -EINVAL;
+ }
+
+ err = bpf_check_uarg_tail_zero(btf_data, sizeof(btf->hdr), hdr_len);
+ if (err) {
+ if (err == -E2BIG)
+ btf_verifier_log(env, "Unsupported btf_header");
+ return err;
+ }
+
+ hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
+ if (copy_from_user(&btf->hdr, btf_data, hdr_copy))
+ return -EFAULT;
+
+ hdr = &btf->hdr;
+
+ btf_verifier_log_hdr(env, btf_data_size);
+
+ if (hdr->magic != BTF_MAGIC) {
+ btf_verifier_log(env, "Invalid magic");
+ return -EINVAL;
+ }
+
+ if (hdr->version != BTF_VERSION) {
+ btf_verifier_log(env, "Unsupported version");
+ return -ENOTSUPP;
+ }
+
+ if (hdr->flags) {
+ btf_verifier_log(env, "Unsupported flags");
+ return -ENOTSUPP;
+ }
+
+ if (btf_data_size == hdr->hdr_len) {
+ btf_verifier_log(env, "No data");
+ return -EINVAL;
+ }
+
+ err = btf_check_sec_info(env, btf_data_size);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size,
+ u32 log_level, char __user *log_ubuf, u32 log_size)
+{
+ struct btf_verifier_env *env = NULL;
+ struct bpf_verifier_log *log;
+ struct btf *btf = NULL;
+ u8 *data;
+ int err;
+
+ if (btf_data_size > BTF_MAX_SIZE)
+ return ERR_PTR(-E2BIG);
+
+ env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
+ if (!env)
+ return ERR_PTR(-ENOMEM);
+
+ log = &env->log;
+ if (log_level || log_ubuf || log_size) {
+ /* user requested verbose verifier output
+ * and supplied buffer to store the verification trace
+ */
+ log->level = log_level;
+ log->ubuf = log_ubuf;
+ log->len_total = log_size;
+
+ /* log attributes have to be sane */
+ if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
+ !log->level || !log->ubuf) {
+ err = -EINVAL;
+ goto errout;
+ }
+ }
+
+ btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
+ if (!btf) {
+ err = -ENOMEM;
+ goto errout;
+ }
+ env->btf = btf;
+
+ err = btf_parse_hdr(env, btf_data, btf_data_size);
+ if (err)
+ goto errout;
+
+ data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
+ if (!data) {
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ btf->data = data;
+ btf->data_size = btf_data_size;
+ btf->nohdr_data = btf->data + btf->hdr.hdr_len;
+
+ if (copy_from_user(data, btf_data, btf_data_size)) {
+ err = -EFAULT;
+ goto errout;
+ }
+
+ err = btf_parse_str_sec(env);
+ if (err)
+ goto errout;
+
+ err = btf_parse_type_sec(env);
+ if (err)
+ goto errout;
+
+ if (log->level && bpf_verifier_log_full(log)) {
+ err = -ENOSPC;
+ goto errout;
+ }
+
+ btf_verifier_env_free(env);
+ refcount_set(&btf->refcnt, 1);
+ return btf;
+
+errout:
+ btf_verifier_env_free(env);
+ if (btf)
+ btf_free(btf);
+ return ERR_PTR(err);
+}
+
+void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
+ struct seq_file *m)
+{
+ const struct btf_type *t = btf_type_by_id(btf, type_id);
+
+ btf_type_ops(t)->seq_show(btf, t, type_id, obj, 0, m);
+}
+
+static int btf_release(struct inode *inode, struct file *filp)
+{
+ btf_put(filp->private_data);
+ return 0;
+}
+
+const struct file_operations btf_fops = {
+ .release = btf_release,
+};
+
+static int __btf_new_fd(struct btf *btf)
+{
+ return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
+}
+
+int btf_new_fd(const union bpf_attr *attr)
+{
+ struct btf *btf;
+ int ret;
+
+ btf = btf_parse(u64_to_user_ptr(attr->btf),
+ attr->btf_size, attr->btf_log_level,
+ u64_to_user_ptr(attr->btf_log_buf),
+ attr->btf_log_size);
+ if (IS_ERR(btf))
+ return PTR_ERR(btf);
+
+ ret = btf_alloc_id(btf);
+ if (ret) {
+ btf_free(btf);
+ return ret;
+ }
+
+ /*
+ * The BTF ID is published to the userspace.
+ * All BTF free must go through call_rcu() from
+ * now on (i.e. free by calling btf_put()).
+ */
+
+ ret = __btf_new_fd(btf);
+ if (ret < 0)
+ btf_put(btf);
+
+ return ret;
+}
+
+struct btf *btf_get_by_fd(int fd)
+{
+ struct btf *btf;
+ struct fd f;
+
+ f = fdget(fd);
+
+ if (!f.file)
+ return ERR_PTR(-EBADF);
+
+ if (f.file->f_op != &btf_fops) {
+ fdput(f);
+ return ERR_PTR(-EINVAL);
+ }
+
+ btf = f.file->private_data;
+ refcount_inc(&btf->refcnt);
+ fdput(f);
+
+ return btf;
+}
+
+int btf_get_info_by_fd(const struct btf *btf,
+ const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ struct bpf_btf_info __user *uinfo;
+ struct bpf_btf_info info = {};
+ u32 info_copy, btf_copy;
+ void __user *ubtf;
+ u32 uinfo_len;
+
+ uinfo = u64_to_user_ptr(attr->info.info);
+ uinfo_len = attr->info.info_len;
+
+ info_copy = min_t(u32, uinfo_len, sizeof(info));
+ if (copy_from_user(&info, uinfo, info_copy))
+ return -EFAULT;
+
+ info.id = btf->id;
+ ubtf = u64_to_user_ptr(info.btf);
+ btf_copy = min_t(u32, btf->data_size, info.btf_size);
+ if (copy_to_user(ubtf, btf->data, btf_copy))
+ return -EFAULT;
+ info.btf_size = btf->data_size;
+
+ if (copy_to_user(uinfo, &info, info_copy) ||
+ put_user(info_copy, &uattr->info.info_len))
+ return -EFAULT;
+
+ return 0;
+}
+
+int btf_get_fd_by_id(u32 id)
+{
+ struct btf *btf;
+ int fd;
+
+ rcu_read_lock();
+ btf = idr_find(&btf_idr, id);
+ if (!btf || !refcount_inc_not_zero(&btf->refcnt))
+ btf = ERR_PTR(-ENOENT);
+ rcu_read_unlock();
+
+ if (IS_ERR(btf))
+ return PTR_ERR(btf);
+
+ fd = __btf_new_fd(btf);
+ if (fd < 0)
+ btf_put(btf);
+
+ return fd;
+}
+
+u32 btf_id(const struct btf *btf)
+{
+ return btf->id;
+}