Pavel Emelianov 7be77e20d5 Fix user struct leakage with locked IPC shem segment ... When user locks an ipc shmem segmant with SHM_LOCK ctl and the segment is already locked the shmem_lock() function returns 0. After this the subsequent code leaks the existing user struct: == ipc/shm.c: sys_shmctl() == ... err = shmem_lock(shp->shm_file, 1, user); if (!err) { shp->shm_perm.mode |= SHM_LOCKED; shp->mlock_user = user; } ... == Other results of this are: 1. the new shp->mlock_user is not get-ed and will point to freed memory when the task dies. 2. the RLIMIT_MEMLOCK is screwed on both user structs. The exploit looks like this: == id = shmget(...); setresuid(uid, 0, 0); shmctl(id, SHM_LOCK, NULL); setresuid(uid + 1, 0, 0); shmctl(id, SHM_LOCK, NULL); == My solution is to return 0 to the userspace and do not change the segment's user. Signed-off-by: Pavel Emelianov <xemul@openvz.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2007-07-31 15:39:40 -07:00
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compat.c
compat_mq.c
ipc_sysctl.c
Makefile
mqueue.c	mm: Remove slab destructors from kmem_cache_create().	2007-07-20 10:11:58 +09:00
msg.c
msgutil.c
sem.c
shm.c	Fix user struct leakage with locked IPC shem segment	2007-07-31 15:39:40 -07:00
util.c
util.h