make sure curr_info.sig is not-NULL before derreferencing it.

similar to  Bug 1451

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@21050 f5534014-38df-0310-8fa8-9805f1628bb7

diff --git a/asn1/h248/packet-h248-template.c b/asn1/h248/packet-h248-template.c
index 5601f373e6d4f00a2b81d9dcdaf27695893dd321..666ef53f4acac06097a27ade53eb012e21105aa2 100644 (file)
--- a/asn1/h248/packet-h248-template.c
+++ b/asn1/h248/packet-h248-template.c
@@ -1042,7 +1042,7 @@ static int dissect_h248_SigParameterName(gboolean implicit_tag _U_, tvbuff_t *tv
                }
        }
 
-       if (curr_info.sig->param_names && ( strval = match_strval(param_id, curr_info.sig->param_names) )) {
+       if (curr_info.sig && curr_info.sig->param_names && ( strval = match_strval(param_id, curr_info.sig->param_names) )) {
                strval = ep_strdup_printf("%s (%d)",strval,param_id);
        } else {
                strval = ep_strdup_printf("Unknown (%d)",param_id);