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authorAlexey Gladkov <gladkov.alexey@gmail.com>2020-06-10 20:35:49 +0200
committerEric W. Biederman <ebiederm@xmission.com>2020-06-10 14:54:54 -0500
commit058f2e4da79b23afb56ce3d03d907d6cdd36f2b8 (patch)
tree585a18087f3ac99efdd6400ae9d09392df4732f5 /fs
parent9d78edeaec759f997c303f286ecd39daee166f2a (diff)
downloadlinux-058f2e4da79b23afb56ce3d03d907d6cdd36f2b8.tar.bz2
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')
-rw-r--r--fs/proc/root.c10
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);