isdn/gigaset: fix NULL pointer dereference

In do_action, a NULL pointer might be passed to function start_dial
which will dereference it.
Fix by adding a check for NULL before the call.

Spotted with Coverity.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/isdn/gigaset/ev-layer.c b/drivers/isdn/gigaset/ev-layer.c
index dcae14aef3763cd416c2f6e3d807d44e7c5b4624..0f699ebd81c5361e9d3226c09e5ef651df061230 100644 (file)
--- a/drivers/isdn/gigaset/ev-layer.c
+++ b/drivers/isdn/gigaset/ev-layer.c
@@ -1380,6 +1380,11 @@ static void do_action(int action, struct cardstate *cs,
        /* events from the LL */
 
        case ACT_DIAL:
+               if (!ev->ptr) {
+                       *p_genresp = 1;
+                       *p_resp_code = RSP_ERROR;
+                       break;
+               }
                start_dial(at_state, ev->ptr, ev->parameter);
                break;
        case ACT_ACCEPT: