Commit 28b0a2ab authored by Raphael Zimmer's avatar Raphael Zimmer Committed by Ilya Dryomov
Browse files

libceph: Fix potential null-ptr-deref in decode_choose_args() 



A message of type CEPH_MSG_OSD_MAP contains an OSD map that itself
contains a CRUSH map. When decoding this CRUSH map in crush_decode(), an
array of max_buckets CRUSH buckets is decoded, where some indices may
not refer to actual buckets and are therefore set to NULL. The received
CRUSH map may optionally contain choose_args that get decoded in
decode_choose_args(). When decoding a crush_choose_arg_map, a series of
choose_args for different buckets is decoded, with the bucket_index
being read from the incoming message. It is only checked that the bucket
index does not exceed max_buckets, but not that it doesn't point to an
index with a NULL bucket. If a (potentially corrupted) message contains
a crush_choose_arg_map including such a bucket_index, a null pointer
dereference may occur in the subsequent processing when attempting to
access the bucket with the given index.

This patch fixes the issue by extending the affected check. Now, it is
only attempted to access the bucket if it is not NULL.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarRaphael Zimmer <raphael.zimmer@tu-ilmenau.de>
Reviewed-by: default avatarIlya Dryomov <idryomov@gmail.com>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent d289478c

net/ceph/osdmap.c

+2 −1
Original line number Diff line number Diff line
@@ -388,7 +388,8 @@ static int decode_choose_args(void **p, void *end, struct crush_map *c) 
				goto fail;



			if (arg->ids_size &&

			    arg->ids_size != c->buckets[bucket_index]->size)

			    (!c->buckets[bucket_index] ||

			     arg->ids_size != c->buckets[bucket_index]->size))

				goto e_inval;

		}