libceph: fix overflow in osdmap_apply_incremental()
authorXi Wang <xi.wang@gmail.com>
Thu, 7 Jun 2012 00:35:55 +0000 (19:35 -0500)
committerAlex Elder <elder@dreamhost.com>
Thu, 7 Jun 2012 13:28:16 +0000 (08:28 -0500)
On 32-bit systems, a large `pglen' would overflow `pglen*sizeof(u32)'
and bypass the check ceph_decode_need(p, end, pglen*sizeof(u32), bad).
It would also overflow the subsequent kmalloc() size, leading to
out-of-bounds write.

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

index d70aaca4a45dae26710cf504da5da179969ac4da..d3de09f519b27455719120f78902bb41fd07d38d 100644 (file)
@@ -893,6 +893,10 @@ struct ceph_osdmap *osdmap_apply_incremental(void **p, void *end,
                        (void) __remove_pg_mapping(&map->pg_temp, pgid);
 
                        /* insert */
+                       if (pglen > (UINT_MAX - sizeof(*pg)) / sizeof(u32)) {
+                               err = -EINVAL;
+                               goto bad;
+                       }
                        pg = kmalloc(sizeof(*pg) + sizeof(u32)*pglen, GFP_NOFS);
                        if (!pg) {
                                err = -ENOMEM;