3.5.7u1 -stable review patch.  If anyone has any objections, please let me know.

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

From: Xi Wang <xi.w...@gmail.com>

commit ad3b904c07dfa88603689bf9a67bffbb9b99beb5 upstream.

`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.

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

Signed-off-by: Xi Wang <xi.w...@gmail.com>
Reviewed-by: Alex Elder <el...@inktank.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesin...@canonical.com>
---
 net/ceph/osdmap.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 81e3b84..95b2762 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;
        }
-- 
1.7.9.5

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