v4.19.13 snapshot.
diff --git a/security/apparmor/file.c b/security/apparmor/file.c
new file mode 100644
index 0000000..4285943
--- /dev/null
+++ b/security/apparmor/file.c
@@ -0,0 +1,707 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor mediation of files
+ *
+ * Copyright (C) 1998-2008 Novell/SUSE
+ * Copyright 2009-2010 Canonical Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ */
+
+#include <linux/tty.h>
+#include <linux/fdtable.h>
+#include <linux/file.h>
+
+#include "include/apparmor.h"
+#include "include/audit.h"
+#include "include/cred.h"
+#include "include/file.h"
+#include "include/match.h"
+#include "include/net.h"
+#include "include/path.h"
+#include "include/policy.h"
+#include "include/label.h"
+
+static u32 map_mask_to_chr_mask(u32 mask)
+{
+ u32 m = mask & PERMS_CHRS_MASK;
+
+ if (mask & AA_MAY_GETATTR)
+ m |= MAY_READ;
+ if (mask & (AA_MAY_SETATTR | AA_MAY_CHMOD | AA_MAY_CHOWN))
+ m |= MAY_WRITE;
+
+ return m;
+}
+
+/**
+ * audit_file_mask - convert mask to permission string
+ * @buffer: buffer to write string to (NOT NULL)
+ * @mask: permission mask to convert
+ */
+static void audit_file_mask(struct audit_buffer *ab, u32 mask)
+{
+ char str[10];
+
+ aa_perm_mask_to_str(str, sizeof(str), aa_file_perm_chrs,
+ map_mask_to_chr_mask(mask));
+ audit_log_string(ab, str);
+}
+
+/**
+ * file_audit_cb - call back for file specific audit fields
+ * @ab: audit_buffer (NOT NULL)
+ * @va: audit struct to audit values of (NOT NULL)
+ */
+static void file_audit_cb(struct audit_buffer *ab, void *va)
+{
+ struct common_audit_data *sa = va;
+ kuid_t fsuid = current_fsuid();
+
+ if (aad(sa)->request & AA_AUDIT_FILE_MASK) {
+ audit_log_format(ab, " requested_mask=");
+ audit_file_mask(ab, aad(sa)->request);
+ }
+ if (aad(sa)->denied & AA_AUDIT_FILE_MASK) {
+ audit_log_format(ab, " denied_mask=");
+ audit_file_mask(ab, aad(sa)->denied);
+ }
+ if (aad(sa)->request & AA_AUDIT_FILE_MASK) {
+ audit_log_format(ab, " fsuid=%d",
+ from_kuid(&init_user_ns, fsuid));
+ audit_log_format(ab, " ouid=%d",
+ from_kuid(&init_user_ns, aad(sa)->fs.ouid));
+ }
+
+ if (aad(sa)->peer) {
+ audit_log_format(ab, " target=");
+ aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
+ FLAG_VIEW_SUBNS, GFP_ATOMIC);
+ } else if (aad(sa)->fs.target) {
+ audit_log_format(ab, " target=");
+ audit_log_untrustedstring(ab, aad(sa)->fs.target);
+ }
+}
+
+/**
+ * aa_audit_file - handle the auditing of file operations
+ * @profile: the profile being enforced (NOT NULL)
+ * @perms: the permissions computed for the request (NOT NULL)
+ * @op: operation being mediated
+ * @request: permissions requested
+ * @name: name of object being mediated (MAYBE NULL)
+ * @target: name of target (MAYBE NULL)
+ * @tlabel: target label (MAY BE NULL)
+ * @ouid: object uid
+ * @info: extra information message (MAYBE NULL)
+ * @error: 0 if operation allowed else failure error code
+ *
+ * Returns: %0 or error on failure
+ */
+int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms,
+ const char *op, u32 request, const char *name,
+ const char *target, struct aa_label *tlabel,
+ kuid_t ouid, const char *info, int error)
+{
+ int type = AUDIT_APPARMOR_AUTO;
+ DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_TASK, op);
+
+ sa.u.tsk = NULL;
+ aad(&sa)->request = request;
+ aad(&sa)->name = name;
+ aad(&sa)->fs.target = target;
+ aad(&sa)->peer = tlabel;
+ aad(&sa)->fs.ouid = ouid;
+ aad(&sa)->info = info;
+ aad(&sa)->error = error;
+ sa.u.tsk = NULL;
+
+ if (likely(!aad(&sa)->error)) {
+ u32 mask = perms->audit;
+
+ if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
+ mask = 0xffff;
+
+ /* mask off perms that are not being force audited */
+ aad(&sa)->request &= mask;
+
+ if (likely(!aad(&sa)->request))
+ return 0;
+ type = AUDIT_APPARMOR_AUDIT;
+ } else {
+ /* only report permissions that were denied */
+ aad(&sa)->request = aad(&sa)->request & ~perms->allow;
+ AA_BUG(!aad(&sa)->request);
+
+ if (aad(&sa)->request & perms->kill)
+ type = AUDIT_APPARMOR_KILL;
+
+ /* quiet known rejects, assumes quiet and kill do not overlap */
+ if ((aad(&sa)->request & perms->quiet) &&
+ AUDIT_MODE(profile) != AUDIT_NOQUIET &&
+ AUDIT_MODE(profile) != AUDIT_ALL)
+ aad(&sa)->request &= ~perms->quiet;
+
+ if (!aad(&sa)->request)
+ return aad(&sa)->error;
+ }
+
+ aad(&sa)->denied = aad(&sa)->request & ~perms->allow;
+ return aa_audit(type, profile, &sa, file_audit_cb);
+}
+
+/**
+ * is_deleted - test if a file has been completely unlinked
+ * @dentry: dentry of file to test for deletion (NOT NULL)
+ *
+ * Returns: %1 if deleted else %0
+ */
+static inline bool is_deleted(struct dentry *dentry)
+{
+ if (d_unlinked(dentry) && d_backing_inode(dentry)->i_nlink == 0)
+ return 1;
+ return 0;
+}
+
+static int path_name(const char *op, struct aa_label *label,
+ const struct path *path, int flags, char *buffer,
+ const char **name, struct path_cond *cond, u32 request)
+{
+ struct aa_profile *profile;
+ const char *info = NULL;
+ int error;
+
+ error = aa_path_name(path, flags, buffer, name, &info,
+ labels_profile(label)->disconnected);
+ if (error) {
+ fn_for_each_confined(label, profile,
+ aa_audit_file(profile, &nullperms, op, request, *name,
+ NULL, NULL, cond->uid, info, error));
+ return error;
+ }
+
+ return 0;
+}
+
+/**
+ * map_old_perms - map old file perms layout to the new layout
+ * @old: permission set in old mapping
+ *
+ * Returns: new permission mapping
+ */
+static u32 map_old_perms(u32 old)
+{
+ u32 new = old & 0xf;
+ if (old & MAY_READ)
+ new |= AA_MAY_GETATTR | AA_MAY_OPEN;
+ if (old & MAY_WRITE)
+ new |= AA_MAY_SETATTR | AA_MAY_CREATE | AA_MAY_DELETE |
+ AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_OPEN;
+ if (old & 0x10)
+ new |= AA_MAY_LINK;
+ /* the old mapping lock and link_subset flags where overlaid
+ * and use was determined by part of a pair that they were in
+ */
+ if (old & 0x20)
+ new |= AA_MAY_LOCK | AA_LINK_SUBSET;
+ if (old & 0x40) /* AA_EXEC_MMAP */
+ new |= AA_EXEC_MMAP;
+
+ return new;
+}
+
+/**
+ * aa_compute_fperms - convert dfa compressed perms to internal perms
+ * @dfa: dfa to compute perms for (NOT NULL)
+ * @state: state in dfa
+ * @cond: conditions to consider (NOT NULL)
+ *
+ * TODO: convert from dfa + state to permission entry, do computation conversion
+ * at load time.
+ *
+ * Returns: computed permission set
+ */
+struct aa_perms aa_compute_fperms(struct aa_dfa *dfa, unsigned int state,
+ struct path_cond *cond)
+{
+ /* FIXME: change over to new dfa format
+ * currently file perms are encoded in the dfa, new format
+ * splits the permissions from the dfa. This mapping can be
+ * done at profile load
+ */
+ struct aa_perms perms = { };
+
+ if (uid_eq(current_fsuid(), cond->uid)) {
+ perms.allow = map_old_perms(dfa_user_allow(dfa, state));
+ perms.audit = map_old_perms(dfa_user_audit(dfa, state));
+ perms.quiet = map_old_perms(dfa_user_quiet(dfa, state));
+ perms.xindex = dfa_user_xindex(dfa, state);
+ } else {
+ perms.allow = map_old_perms(dfa_other_allow(dfa, state));
+ perms.audit = map_old_perms(dfa_other_audit(dfa, state));
+ perms.quiet = map_old_perms(dfa_other_quiet(dfa, state));
+ perms.xindex = dfa_other_xindex(dfa, state);
+ }
+ perms.allow |= AA_MAY_GETATTR;
+
+ /* change_profile wasn't determined by ownership in old mapping */
+ if (ACCEPT_TABLE(dfa)[state] & 0x80000000)
+ perms.allow |= AA_MAY_CHANGE_PROFILE;
+ if (ACCEPT_TABLE(dfa)[state] & 0x40000000)
+ perms.allow |= AA_MAY_ONEXEC;
+
+ return perms;
+}
+
+/**
+ * aa_str_perms - find permission that match @name
+ * @dfa: to match against (MAYBE NULL)
+ * @state: state to start matching in
+ * @name: string to match against dfa (NOT NULL)
+ * @cond: conditions to consider for permission set computation (NOT NULL)
+ * @perms: Returns - the permissions found when matching @name
+ *
+ * Returns: the final state in @dfa when beginning @start and walking @name
+ */
+unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
+ const char *name, struct path_cond *cond,
+ struct aa_perms *perms)
+{
+ unsigned int state;
+ state = aa_dfa_match(dfa, start, name);
+ *perms = aa_compute_fperms(dfa, state, cond);
+
+ return state;
+}
+
+int __aa_path_perm(const char *op, struct aa_profile *profile, const char *name,
+ u32 request, struct path_cond *cond, int flags,
+ struct aa_perms *perms)
+{
+ int e = 0;
+
+ if (profile_unconfined(profile))
+ return 0;
+ aa_str_perms(profile->file.dfa, profile->file.start, name, cond, perms);
+ if (request & ~perms->allow)
+ e = -EACCES;
+ return aa_audit_file(profile, perms, op, request, name, NULL, NULL,
+ cond->uid, NULL, e);
+}
+
+
+static int profile_path_perm(const char *op, struct aa_profile *profile,
+ const struct path *path, char *buffer, u32 request,
+ struct path_cond *cond, int flags,
+ struct aa_perms *perms)
+{
+ const char *name;
+ int error;
+
+ if (profile_unconfined(profile))
+ return 0;
+
+ error = path_name(op, &profile->label, path,
+ flags | profile->path_flags, buffer, &name, cond,
+ request);
+ if (error)
+ return error;
+ return __aa_path_perm(op, profile, name, request, cond, flags,
+ perms);
+}
+
+/**
+ * aa_path_perm - do permissions check & audit for @path
+ * @op: operation being checked
+ * @label: profile being enforced (NOT NULL)
+ * @path: path to check permissions of (NOT NULL)
+ * @flags: any additional path flags beyond what the profile specifies
+ * @request: requested permissions
+ * @cond: conditional info for this request (NOT NULL)
+ *
+ * Returns: %0 else error if access denied or other error
+ */
+int aa_path_perm(const char *op, struct aa_label *label,
+ const struct path *path, int flags, u32 request,
+ struct path_cond *cond)
+{
+ struct aa_perms perms = {};
+ struct aa_profile *profile;
+ char *buffer = NULL;
+ int error;
+
+ flags |= PATH_DELEGATE_DELETED | (S_ISDIR(cond->mode) ? PATH_IS_DIR :
+ 0);
+ get_buffers(buffer);
+ error = fn_for_each_confined(label, profile,
+ profile_path_perm(op, profile, path, buffer, request,
+ cond, flags, &perms));
+
+ put_buffers(buffer);
+
+ return error;
+}
+
+/**
+ * xindex_is_subset - helper for aa_path_link
+ * @link: link permission set
+ * @target: target permission set
+ *
+ * test target x permissions are equal OR a subset of link x permissions
+ * this is done as part of the subset test, where a hardlink must have
+ * a subset of permissions that the target has.
+ *
+ * Returns: %1 if subset else %0
+ */
+static inline bool xindex_is_subset(u32 link, u32 target)
+{
+ if (((link & ~AA_X_UNSAFE) != (target & ~AA_X_UNSAFE)) ||
+ ((link & AA_X_UNSAFE) && !(target & AA_X_UNSAFE)))
+ return 0;
+
+ return 1;
+}
+
+static int profile_path_link(struct aa_profile *profile,
+ const struct path *link, char *buffer,
+ const struct path *target, char *buffer2,
+ struct path_cond *cond)
+{
+ const char *lname, *tname = NULL;
+ struct aa_perms lperms = {}, perms;
+ const char *info = NULL;
+ u32 request = AA_MAY_LINK;
+ unsigned int state;
+ int error;
+
+ error = path_name(OP_LINK, &profile->label, link, profile->path_flags,
+ buffer, &lname, cond, AA_MAY_LINK);
+ if (error)
+ goto audit;
+
+ /* buffer2 freed below, tname is pointer in buffer2 */
+ error = path_name(OP_LINK, &profile->label, target, profile->path_flags,
+ buffer2, &tname, cond, AA_MAY_LINK);
+ if (error)
+ goto audit;
+
+ error = -EACCES;
+ /* aa_str_perms - handles the case of the dfa being NULL */
+ state = aa_str_perms(profile->file.dfa, profile->file.start, lname,
+ cond, &lperms);
+
+ if (!(lperms.allow & AA_MAY_LINK))
+ goto audit;
+
+ /* test to see if target can be paired with link */
+ state = aa_dfa_null_transition(profile->file.dfa, state);
+ aa_str_perms(profile->file.dfa, state, tname, cond, &perms);
+
+ /* force audit/quiet masks for link are stored in the second entry
+ * in the link pair.
+ */
+ lperms.audit = perms.audit;
+ lperms.quiet = perms.quiet;
+ lperms.kill = perms.kill;
+
+ if (!(perms.allow & AA_MAY_LINK)) {
+ info = "target restricted";
+ lperms = perms;
+ goto audit;
+ }
+
+ /* done if link subset test is not required */
+ if (!(perms.allow & AA_LINK_SUBSET))
+ goto done_tests;
+
+ /* Do link perm subset test requiring allowed permission on link are
+ * a subset of the allowed permissions on target.
+ */
+ aa_str_perms(profile->file.dfa, profile->file.start, tname, cond,
+ &perms);
+
+ /* AA_MAY_LINK is not considered in the subset test */
+ request = lperms.allow & ~AA_MAY_LINK;
+ lperms.allow &= perms.allow | AA_MAY_LINK;
+
+ request |= AA_AUDIT_FILE_MASK & (lperms.allow & ~perms.allow);
+ if (request & ~lperms.allow) {
+ goto audit;
+ } else if ((lperms.allow & MAY_EXEC) &&
+ !xindex_is_subset(lperms.xindex, perms.xindex)) {
+ lperms.allow &= ~MAY_EXEC;
+ request |= MAY_EXEC;
+ info = "link not subset of target";
+ goto audit;
+ }
+
+done_tests:
+ error = 0;
+
+audit:
+ return aa_audit_file(profile, &lperms, OP_LINK, request, lname, tname,
+ NULL, cond->uid, info, error);
+}
+
+/**
+ * aa_path_link - Handle hard link permission check
+ * @label: the label being enforced (NOT NULL)
+ * @old_dentry: the target dentry (NOT NULL)
+ * @new_dir: directory the new link will be created in (NOT NULL)
+ * @new_dentry: the link being created (NOT NULL)
+ *
+ * Handle the permission test for a link & target pair. Permission
+ * is encoded as a pair where the link permission is determined
+ * first, and if allowed, the target is tested. The target test
+ * is done from the point of the link match (not start of DFA)
+ * making the target permission dependent on the link permission match.
+ *
+ * The subset test if required forces that permissions granted
+ * on link are a subset of the permission granted to target.
+ *
+ * Returns: %0 if allowed else error
+ */
+int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
+ const struct path *new_dir, struct dentry *new_dentry)
+{
+ struct path link = { .mnt = new_dir->mnt, .dentry = new_dentry };
+ struct path target = { .mnt = new_dir->mnt, .dentry = old_dentry };
+ struct path_cond cond = {
+ d_backing_inode(old_dentry)->i_uid,
+ d_backing_inode(old_dentry)->i_mode
+ };
+ char *buffer = NULL, *buffer2 = NULL;
+ struct aa_profile *profile;
+ int error;
+
+ /* buffer freed below, lname is pointer in buffer */
+ get_buffers(buffer, buffer2);
+ error = fn_for_each_confined(label, profile,
+ profile_path_link(profile, &link, buffer, &target,
+ buffer2, &cond));
+ put_buffers(buffer, buffer2);
+
+ return error;
+}
+
+static void update_file_ctx(struct aa_file_ctx *fctx, struct aa_label *label,
+ u32 request)
+{
+ struct aa_label *l, *old;
+
+ /* update caching of label on file_ctx */
+ spin_lock(&fctx->lock);
+ old = rcu_dereference_protected(fctx->label,
+ spin_is_locked(&fctx->lock));
+ l = aa_label_merge(old, label, GFP_ATOMIC);
+ if (l) {
+ if (l != old) {
+ rcu_assign_pointer(fctx->label, l);
+ aa_put_label(old);
+ } else
+ aa_put_label(l);
+ fctx->allow |= request;
+ }
+ spin_unlock(&fctx->lock);
+}
+
+static int __file_path_perm(const char *op, struct aa_label *label,
+ struct aa_label *flabel, struct file *file,
+ u32 request, u32 denied)
+{
+ struct aa_profile *profile;
+ struct aa_perms perms = {};
+ struct path_cond cond = {
+ .uid = file_inode(file)->i_uid,
+ .mode = file_inode(file)->i_mode
+ };
+ char *buffer;
+ int flags, error;
+
+ /* revalidation due to label out of date. No revocation at this time */
+ if (!denied && aa_label_is_subset(flabel, label))
+ /* TODO: check for revocation on stale profiles */
+ return 0;
+
+ flags = PATH_DELEGATE_DELETED | (S_ISDIR(cond.mode) ? PATH_IS_DIR : 0);
+ get_buffers(buffer);
+
+ /* check every profile in task label not in current cache */
+ error = fn_for_each_not_in_set(flabel, label, profile,
+ profile_path_perm(op, profile, &file->f_path, buffer,
+ request, &cond, flags, &perms));
+ if (denied && !error) {
+ /*
+ * check every profile in file label that was not tested
+ * in the initial check above.
+ *
+ * TODO: cache full perms so this only happens because of
+ * conditionals
+ * TODO: don't audit here
+ */
+ if (label == flabel)
+ error = fn_for_each(label, profile,
+ profile_path_perm(op, profile, &file->f_path,
+ buffer, request, &cond, flags,
+ &perms));
+ else
+ error = fn_for_each_not_in_set(label, flabel, profile,
+ profile_path_perm(op, profile, &file->f_path,
+ buffer, request, &cond, flags,
+ &perms));
+ }
+ if (!error)
+ update_file_ctx(file_ctx(file), label, request);
+
+ put_buffers(buffer);
+
+ return error;
+}
+
+static int __file_sock_perm(const char *op, struct aa_label *label,
+ struct aa_label *flabel, struct file *file,
+ u32 request, u32 denied)
+{
+ struct socket *sock = (struct socket *) file->private_data;
+ int error;
+
+ AA_BUG(!sock);
+
+ /* revalidation due to label out of date. No revocation at this time */
+ if (!denied && aa_label_is_subset(flabel, label))
+ return 0;
+
+ /* TODO: improve to skip profiles cached in flabel */
+ error = aa_sock_file_perm(label, op, request, sock);
+ if (denied) {
+ /* TODO: improve to skip profiles checked above */
+ /* check every profile in file label to is cached */
+ last_error(error, aa_sock_file_perm(flabel, op, request, sock));
+ }
+ if (!error)
+ update_file_ctx(file_ctx(file), label, request);
+
+ return error;
+}
+
+/**
+ * aa_file_perm - do permission revalidation check & audit for @file
+ * @op: operation being checked
+ * @label: label being enforced (NOT NULL)
+ * @file: file to revalidate access permissions on (NOT NULL)
+ * @request: requested permissions
+ *
+ * Returns: %0 if access allowed else error
+ */
+int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
+ u32 request)
+{
+ struct aa_file_ctx *fctx;
+ struct aa_label *flabel;
+ u32 denied;
+ int error = 0;
+
+ AA_BUG(!label);
+ AA_BUG(!file);
+
+ fctx = file_ctx(file);
+
+ rcu_read_lock();
+ flabel = rcu_dereference(fctx->label);
+ AA_BUG(!flabel);
+
+ /* revalidate access, if task is unconfined, or the cached cred
+ * doesn't match or if the request is for more permissions than
+ * was granted.
+ *
+ * Note: the test for !unconfined(flabel) is to handle file
+ * delegation from unconfined tasks
+ */
+ denied = request & ~fctx->allow;
+ if (unconfined(label) || unconfined(flabel) ||
+ (!denied && aa_label_is_subset(flabel, label)))
+ goto done;
+
+ /* TODO: label cross check */
+
+ if (file->f_path.mnt && path_mediated_fs(file->f_path.dentry))
+ error = __file_path_perm(op, label, flabel, file, request,
+ denied);
+
+ else if (S_ISSOCK(file_inode(file)->i_mode))
+ error = __file_sock_perm(op, label, flabel, file, request,
+ denied);
+done:
+ rcu_read_unlock();
+
+ return error;
+}
+
+static void revalidate_tty(struct aa_label *label)
+{
+ struct tty_struct *tty;
+ int drop_tty = 0;
+
+ tty = get_current_tty();
+ if (!tty)
+ return;
+
+ spin_lock(&tty->files_lock);
+ if (!list_empty(&tty->tty_files)) {
+ struct tty_file_private *file_priv;
+ struct file *file;
+ /* TODO: Revalidate access to controlling tty. */
+ file_priv = list_first_entry(&tty->tty_files,
+ struct tty_file_private, list);
+ file = file_priv->file;
+
+ if (aa_file_perm(OP_INHERIT, label, file, MAY_READ | MAY_WRITE))
+ drop_tty = 1;
+ }
+ spin_unlock(&tty->files_lock);
+ tty_kref_put(tty);
+
+ if (drop_tty)
+ no_tty();
+}
+
+static int match_file(const void *p, struct file *file, unsigned int fd)
+{
+ struct aa_label *label = (struct aa_label *)p;
+
+ if (aa_file_perm(OP_INHERIT, label, file, aa_map_file_to_perms(file)))
+ return fd + 1;
+ return 0;
+}
+
+
+/* based on selinux's flush_unauthorized_files */
+void aa_inherit_files(const struct cred *cred, struct files_struct *files)
+{
+ struct aa_label *label = aa_get_newest_cred_label(cred);
+ struct file *devnull = NULL;
+ unsigned int n;
+
+ revalidate_tty(label);
+
+ /* Revalidate access to inherited open files. */
+ n = iterate_fd(files, 0, match_file, label);
+ if (!n) /* none found? */
+ goto out;
+
+ devnull = dentry_open(&aa_null, O_RDWR, cred);
+ if (IS_ERR(devnull))
+ devnull = NULL;
+ /* replace all the matching ones with this */
+ do {
+ replace_fd(n - 1, devnull, 0);
+ } while ((n = iterate_fd(files, n, match_file, label)) != 0);
+ if (devnull)
+ fput(devnull);
+out:
+ aa_put_label(label);
+}