[031/127] ipc: shm: fix information leak to userland

[Greg KH]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Vasiliy Kulikov <segooon@xxxxxxxxx>

commit 3af54c9bd9e6f14f896aac1bb0e8405ae0bc7a44 upstream.

The shmid_ds structure is copied to userland with shm_unused{,2,3}
fields unitialized.  It leads to leaking of contents of kernel stack
memory.

Signed-off-by: Vasiliy Kulikov <segooon@xxxxxxxxx>
Acked-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 ipc/shm.c |    1 +
 1 file changed, 1 insertion(+)

--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -474,6 +474,7 @@ static inline unsigned long copy_shmid_t
 	    {
 		struct shmid_ds out;
 
+		memset(&out, 0, sizeof(out));
 		ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 		out.shm_segsz	= in->shm_segsz;
 		out.shm_atime	= in->shm_atime;


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