diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2023-06-29 07:20:44 +0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2023-07-04 13:29:29 +0200 |
| commit | 69562eb0bd3e6bb8e522a7b254334e0fb30dff0c (patch) | |
| tree | 8b322cf155785737c7aa57f6337e6608760a2a62 | |
| parent | a901a3568fd26ca9c4a82d8bc5ed5b3ed844d451 (diff) | |
fanotify: disallow mount/sb marks on kernel internal pseudo fs
Hopefully, nobody is trying to abuse mount/sb marks for watching all
anonymous pipes/inodes.
I cannot think of a good reason to allow this - it looks like an
oversight that dated back to the original fanotify API.
Link: https://lore.kernel.org/linux-fsdevel/20230628101132.kvchg544mczxv2pm@quack3/
Fixes: 0ff21db9fcc3 ("fanotify: hooks the fanotify_mark syscall to the vfsmount code")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230629042044.25723-1-amir73il@gmail.com>
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 95d7d8790bc3..f69c451018e3 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1623,6 +1623,20 @@ static int fanotify_events_supported(struct fsnotify_group *group, return -EINVAL; /* + * mount and sb marks are not allowed on kernel internal pseudo fs, + * like pipe_mnt, because that would subscribe to events on all the + * anonynous pipes in the system. + * + * SB_NOUSER covers all of the internal pseudo fs whose objects are not + * exposed to user's mount namespace, but there are other SB_KERNMOUNT + * fs, like nsfs, debugfs, for which the value of allowing sb and mount + * mark is questionable. For now we leave them alone. + */ + if (mark_type != FAN_MARK_INODE && + path->mnt->mnt_sb->s_flags & SB_NOUSER) + return -EINVAL; + + /* * We shouldn't have allowed setting dirent events and the directory * flags FAN_ONDIR and FAN_EVENT_ON_CHILD in mask of non-dir inode, * but because we always allowed it, error only when using new APIs. |