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| author |   Alexey Gladkov <gladkov.alexey@gmail.com> | 2020-06-10 20:35:49 +0200 |
|---|---|---|
| committer |   Eric W. Biederman <ebiederm@xmission.com> | 2020-06-10 14:54:54 -0500 |
| commit | 058f2e4da79b23afb56ce3d03d907d6cdd36f2b8 (patch) | |
| tree | 585a18087f3ac99efdd6400ae9d09392df4732f5 /fs/proc | |
| parent | proc: proc_pid_ns takes super_block as an argument (diff) | |
| download | linux-dev-058f2e4da79b23afb56ce3d03d907d6cdd36f2b8.tar.xz linux-dev-058f2e4da79b23afb56ce3d03d907d6cdd36f2b8.zip | |
proc: s_fs_info may be NULL when proc_kill_sb is called
syzbot found that proc_fill_super() fails before filling up sb->s_fs_info,
deactivate_locked_super() will be called and sb->s_fs_info will be NULL.
The proc_kill_sb() does not expect fs_info to be NULL which is wrong.
Link: https://lore.kernel.org/lkml/0000000000002d7ca605a7b8b1c5@google.com
Reported-by: syzbot+4abac52934a48af5ff19@syzkaller.appspotmail.com
Fixes: fa10fed30f25 ("proc: allow to mount many instances of proc in one pid namespace")
Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/root.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/proc/root.c b/fs/proc/root.c index ffebed1999e5..5e444d4f9717 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -264,11 +264,13 @@ static void proc_kill_sb(struct super_block *sb) { struct proc_fs_info *fs_info = proc_sb_info(sb); - if (fs_info->proc_self) - dput(fs_info->proc_self); + if (!fs_info) { + kill_anon_super(sb); + return; + } - if (fs_info->proc_thread_self) - dput(fs_info->proc_thread_self); + dput(fs_info->proc_self); + dput(fs_info->proc_thread_self); kill_anon_super(sb); put_pid_ns(fs_info->pid_ns); |