From: Xi Wang <xi.wang@gmail.com>
Date: Thu, 7 Jun 2012 00:35:55 +0000 (-0500)
Subject: libceph: fix overflow in __decode_pool_names()
X-Git-Tag: v3.6-rc1~36^2~108
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ad3b904c07dfa88603689bf9a67bffbb9b99beb5;p=platform%2Fupstream%2Fkernel-adaptation-pc.git

libceph: fix overflow in __decode_pool_names()

`len' is read from network and thus needs validation.  Otherwise a
large `len' would cause out-of-bounds access via the memcpy() call.
In addition, len = 0xffffffff would overflow the kmalloc() size,
leading to out-of-bounds write.

This patch adds a check of `len' via ceph_decode_need().  Also use
kstrndup rather than kmalloc/memcpy.

[elder@inktank.com: added -ENOMEM return for null kstrndup() result]

Signed-off-by: Xi Wang <xi.wang@gmail.com>
Reviewed-by: Alex Elder <elder@inktank.com>
---

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 1892c52..df47871 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -488,15 +488,16 @@ static int __decode_pool_names(void **p, void *end, struct ceph_osdmap *map)
 		ceph_decode_32_safe(p, end, pool, bad);
 		ceph_decode_32_safe(p, end, len, bad);
 		dout("  pool %d len %d\n", pool, len);
+		ceph_decode_need(p, end, len, bad);
 		pi = __lookup_pg_pool(&map->pg_pools, pool);
 		if (pi) {
+			char *name = kstrndup(*p, len, GFP_NOFS);
+
+			if (!name)
+				return -ENOMEM;
 			kfree(pi->name);
-			pi->name = kmalloc(len + 1, GFP_NOFS);
-			if (pi->name) {
-				memcpy(pi->name, *p, len);
-				pi->name[len] = '\0';
-				dout("  name is %s\n", pi->name);
-			}
+			pi->name = name;
+			dout("  name is %s\n", pi->name);
 		}
 		*p += len;
 	}