https://github.com/torvalds/linux
Revision e08733446e72b983fed850fc5d8bd21b386feb29 authored by Eric Paris on 11 May 2010, 21:17:40 UTC, committed by Eric Paris on 14 May 2010, 15:52:57 UTC
There is a race in the inotify add/rm watch code.  A task can find and
remove a mark which doesn't have all of it's references.  This can
result in a use after free/double free situation.

Task A					Task B
------------				-----------
inotify_new_watch()
 allocate a mark (refcnt == 1)
 add it to the idr
					inotify_rm_watch()
					 inotify_remove_from_idr()
					  fsnotify_put_mark()
					      refcnt hits 0, free
 take reference because we are on idr
 [at this point it is a use after free]
 [time goes on]
 refcnt may hit 0 again, double free

The fix is to take the reference BEFORE the object can be found in the
idr.

Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: <stable@kernel.org>
1 parent 3dbc6fb
History
Tip revision: e08733446e72b983fed850fc5d8bd21b386feb29 authored by Eric Paris on 11 May 2010, 21:17:40 UTC
inotify: race use after free/double free in inotify inode marks
Tip revision: e087334
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