libceph: potential NULL dereference in ceph_osdc_handle_map()

commit b72e19b9225d4297a18715b0998093d843d170fa upstream.

There are two places where we read "nr_maps" if both of them are set to
zero then we would hit a NULL dereference here.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 65d8c3b7df97b9eb28ea1787d4c9c05311091efb..311161eac5c4325ed3bfad0b1713e9f5449798a8 100644 (file)
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -1786,6 +1786,8 @@ void ceph_osdc_handle_map(struct ceph_osd_client *osdc, struct ceph_msg *msg)
                nr_maps--;
        }
 
+       if (!osdc->osdmap)
+               goto bad;
 done:
        downgrade_write(&osdc->map_sem);
        ceph_monc_got_osdmap(&osdc->client->monc, osdc->osdmap->epoch);