[PATCH 093/270] libceph: fix overflow in osdmap_decode()
From: Herton Ronaldo Krzesinski
Date: Mon Nov 26 2012 - 12:05:35 EST
3.5.7u1 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Xi Wang <xi.wang@xxxxxxxxx>
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@xxxxxxxxx>
Reviewed-by: Alex Elder <elder@xxxxxxxxxxx>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@xxxxxxxxxxxxx>
---
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
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