add: msg->contact->body.s[msg->contact->body.len] = 0;
context: static int contact_1918(struct sip_msg* msg){	regmatch_t pmatch;	int fnd;	char backup;	if ((msg->contact == NULL)&&					((parse_headers(msg,HDR_CONTACT,0) == -1))) {		DBG("DEBUG: nathelper/contact1918: Contact not found\n");		return 0;	}	if (msg->contact == NULL || msg->contact->body.s==NULL ) {		DBG("DEBUG: nathelper/contact1918: Contact sanity check failed\n");		return 0;	}	backup=msg->contact->body.s[msg->contact->body.len];	fnd=regexec( key_m1918, msg->contact->body.s, 1, &pmatch, 0)==0;	msg->contact->body.s[msg->contact->body.len]=backup;	return fnd;}