[ 3.5.yuz extended stable ] Patch "libceph: fix overflow in osdmap_decode()" has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    libceph: fix overflow in osdmap_decode()

to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.yuz tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From a97bc8762b8ae43f3ce0f119c7f3e3187b9eb2e7 Mon Sep 17 00:00:00 2001
From: Xi Wang <xi.wang at gmail.com>
Date: Wed, 6 Jun 2012 19:35:55 -0500
Subject: [PATCH 20/78] libceph: fix overflow in osdmap_decode()

commit e91a9b639a691e0982088b5954eaafb5a25c8f1c upstream.

On 32-bit systems, a large `n' would overflow `n * sizeof(u32)' and bypass
the check ceph_decode_need(p, end, n * sizeof(u32), bad).  It would also
overflow the subsequent kmalloc() size, leading to out-of-bounds write.

Signed-off-by: Xi Wang <xi.wang at gmail.com>
Reviewed-by: Alex Elder <elder at inktank.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 net/ceph/osdmap.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 95b2762..bc73341 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -667,6 +667,9 @@ struct ceph_osdmap *osdmap_decode(void **p, void *end)
 		ceph_decode_need(p, end, sizeof(u32) + sizeof(u64), bad);
 		ceph_decode_copy(p, &pgid, sizeof(pgid));
 		n = ceph_decode_32(p);
+		err = -EINVAL;
+		if (n > (UINT_MAX - sizeof(*pg)) / sizeof(u32))
+			goto bad;
 		ceph_decode_need(p, end, n * sizeof(u32), bad);
 		err = -ENOMEM;
 		pg = kmalloc(sizeof(*pg) + n*sizeof(u32), GFP_NOFS);
--
1.7.9.5