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authorSasha Levin <sasha.levin@oracle.com>2014-10-09 15:24:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-09 22:25:45 -0400
commit105d1b425303120c7681abc0761b6fc6c3f8a8e8 (patch)
treedd62771c0fc306feb10074c361bb422b3b634041
parentcafbaae8afdb1e6cf9f4715aea2c897cf407ddfd (diff)
downloadlinux-105d1b425303120c7681abc0761b6fc6c3f8a8e8.tar.bz2
fsnotify: don't put user context if it was never assigned
On some failure paths we may attempt to free user context even if it wasn't assigned yet. This will cause a NULL ptr deref and a kernel BUG. The path I was looking at is in inotify_new_group(): oevent = kmalloc(sizeof(struct inotify_event_info), GFP_KERNEL); if (unlikely(!oevent)) { fsnotify_destroy_group(group); return ERR_PTR(-ENOMEM); } fsnotify_destroy_group() would get called here, but group->inotify_data.user is only getting assigned later: group->inotify_data.user = get_current_user(); Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: John McCutchan <john@johnmccutchan.com> Cc: Robert Love <rlove@rlove.org> Cc: Eric Paris <eparis@parisplace.org> Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/notify/inotify/inotify_fsnotify.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 0f88bc0b4e6c..7d888d77d59a 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -165,8 +165,10 @@ static void inotify_free_group_priv(struct fsnotify_group *group)
/* ideally the idr is empty and we won't hit the BUG in the callback */
idr_for_each(&group->inotify_data.idr, idr_callback, group);
idr_destroy(&group->inotify_data.idr);
- atomic_dec(&group->inotify_data.user->inotify_devs);
- free_uid(group->inotify_data.user);
+ if (group->inotify_data.user) {
+ atomic_dec(&group->inotify_data.user->inotify_devs);
+ free_uid(group->inotify_data.user);
+ }
}
static void inotify_free_event(struct fsnotify_event *fsn_event)