libceph: NULL deref on crush_decode() error path

If there is not enough space then ceph_decode_32_safe() does a goto bad.
We need to return an error code in that situation.  The current code
returns ERR_PTR(0) which is NULL.  The callers are not expecting that
and it results in a NULL dereference.

Fixes: f24e9980eb86 ("ceph: OSD client")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index ffe9e904d4d1d130b0353edbe45d50d236b4f74e..55e3a477f92d4cba92e342d13686b6e3b94204c0 100644 (file)
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -317,6 +317,7 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
                u32 yes;
                struct crush_rule *r;
 
+               err = -EINVAL;
                ceph_decode_32_safe(p, end, yes, bad);
                if (!yes) {
                        dout("crush_decode NO rule %d off %x %p to %p\n",