ast_sockaddr_resolve() in netsock2.c may deref a null pointer

Added a null check in netsock2 ast_sockaddr_resolve() as well as added default initalizers in chan_sip parse_uri_legacy_check() to make sure that invalid uris will make null (and not undefined) user,pass,domain,transport variables

(closes issue #19346)
Reported by: kobaz
Patches: 
      netsock2.patch uploaded by kobaz (license 834)
Tested by: kobaz, Marquis



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@321100 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -13288,6 +13288,20 @@ static int parse_ok_contact(struct sip_pvt *pvt, struct sip_request *req)
 
 /*! \brief parse uri in a way that allows semicolon stripping if legacy mode is enabled */
 static int parse_uri_legacy_check(char *uri, const char *scheme, char **user, char **pass, char **domain, char **transport) {
+	/* Assume invalid to start */
+	if (user) {
+		*user = 0;
+	}
+	if (pass) {
+		*pass = 0;
+	}
+	if (domain) {
+		*domain = 0;
+	}
+	if (transport) {
+		*transport = 0;
+	}
+
 	int ret = parse_uri(uri, scheme, user, pass, domain, transport);
 	if (sip_cfg.legacy_useroption_parsing) { /* if legacy mode is active, strip semis from the user field */
 		char *p;

main/netsock2.c

@@ -232,6 +232,10 @@ int ast_sockaddr_resolve(struct ast_sockaddr **addrs, const char *str,
 	char *s, *host, *port;
 	int	e, i, res_cnt;
 
+	if (!str) {
+		return 0;
+	}
+
 	s = ast_strdupa(str);
 	if (!ast_sockaddr_split_hostport(s, &host, &port, flags)) {
 		return 0;