diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2024-04-16 21:14:52 +0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2024-04-17 15:06:50 +0200 |
| commit | 795bb82d12a16a4cee42845b0e4c7e3276574e5d (patch) | |
| tree | e82347600c4058d7e4c08ca42d7afd9af065405a | |
| parent | a5e57b4d370c6d320e5bfb0c919fe00aee29e039 (diff) | |
fsnotify: fix UAF from FS_ERROR event on a shutting down filesystem
Protect against use after free when filesystem calls fsnotify_sb_error()
during fs shutdown.
Move freeing of sb->s_fsnotify_info to destroy_super_work(), because it
may be accessed from fs shutdown context.
Reported-by: syzbot+5e3f9b2a67b45f16d4e6@syzkaller.appspotmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/linux-fsdevel/20240416173211.4lnmgctyo4jn5fha@quack3/
Fixes: 07a3b8d0bf72 ("fsnotify: lazy attach fsnotify_sb_info state to sb")
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240416181452.567070-1-amir73il@gmail.com>
| -rw-r--r-- | fs/notify/fsnotify.c | 6 | ||||
| -rw-r--r-- | fs/super.c | 1 | ||||
| -rw-r--r-- | include/linux/fsnotify_backend.h | 4 |
3 files changed, 10 insertions, 1 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 2ae965ef37e8..ff69ae24c4e8 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -103,7 +103,11 @@ void fsnotify_sb_delete(struct super_block *sb) WARN_ON(fsnotify_sb_has_priority_watchers(sb, FSNOTIFY_PRIO_CONTENT)); WARN_ON(fsnotify_sb_has_priority_watchers(sb, FSNOTIFY_PRIO_PRE_CONTENT)); - kfree(sbinfo); +} + +void fsnotify_sb_free(struct super_block *sb) +{ + kfree(sb->s_fsnotify_info); } /* diff --git a/fs/super.c b/fs/super.c index 71d9779c42b1..81656c7807db 100644 --- a/fs/super.c +++ b/fs/super.c @@ -274,6 +274,7 @@ static void destroy_super_work(struct work_struct *work) { struct super_block *s = container_of(work, struct super_block, destroy_work); + fsnotify_sb_free(s); security_sb_free(s); put_user_ns(s->s_user_ns); kfree(s->s_subtype); diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 7f1ab8264e41..4dd6143db271 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -576,6 +576,7 @@ extern int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data extern void __fsnotify_inode_delete(struct inode *inode); extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt); extern void fsnotify_sb_delete(struct super_block *sb); +extern void fsnotify_sb_free(struct super_block *sb); extern u32 fsnotify_get_cookie(void); static inline __u32 fsnotify_parent_needed_mask(__u32 mask) @@ -880,6 +881,9 @@ static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt) static inline void fsnotify_sb_delete(struct super_block *sb) {} +static inline void fsnotify_sb_free(struct super_block *sb) +{} + static inline void fsnotify_update_flags(struct dentry *dentry) {} |