TT#14008 add additional NULL checks for `flags`

`flags` being NULL is not really a use case we have right now, but it
might be in the future. Make sure we don't crash.

Change-Id: I4400553fc0a665d94f2e1cdced855250b46d88a4
Warned-by: coverity

daemon/sdp.c

@@ -2433,7 +2433,7 @@ static void insert_crypto1(GString *s, struct call_media *media, struct crypto_p
 			p, &state, &save);
 	p += g_base64_encode_close(0, p, &state, &save);
 
-	if (!flags->sdes_pad) {
+	if (!flags || !flags->sdes_pad) {
 		// truncate trailing ==
 		while (p > b64_buf && p[-1] == '=')
 			p--;
@@ -2444,7 +2444,7 @@ static void insert_crypto1(GString *s, struct call_media *media, struct crypto_p
 	g_string_append(s, cps->params.crypto_suite->name);
 	g_string_append(s, " inline:");
 	g_string_append_len(s, b64_buf, p - b64_buf);
-	if (flags->sdes_lifetime)
+	if (flags && flags->sdes_lifetime)
 		g_string_append(s, "|2^31");
 	if (cps->params.mki_len) {
 		ull = 0;
@@ -2465,10 +2465,10 @@ static void insert_crypto(GString *s, struct call_media *media, struct sdp_ng_fl
 		insert_crypto1(s, media, l->data, flags);
 }
 static void insert_rtcp_attr(GString *s, struct packet_stream *ps, const struct sdp_ng_flags *flags) {
-	if (flags->no_rtcp_attr)
+	if (flags && flags->no_rtcp_attr)
 		return;
 	g_string_append_printf(s, "a=rtcp:%u", ps->selected_sfd->socket.local.port);
-	if (flags->full_rtcp_attr) {
+	if (flags && flags->full_rtcp_attr) {
 		char buf[64];
 		int len;
 		if (!is_addr_unspecified(&flags->parsed_media_address))
@@ -2551,7 +2551,7 @@ struct packet_stream *print_rtcp(GString *s, struct call_media *media, GList *rt
 
 	if (proto_is_rtp(media->protocol)) {
 		if (MEDIA_ISSET(media, RTCP_MUX)
-				&& (flags->opmode == OP_ANSWER || flags->opmode == OP_OTHER
+				&& (!flags || flags->opmode == OP_ANSWER || flags->opmode == OP_OTHER
 					|| flags->opmode == OP_PUBLISH
 					|| ((flags->opmode == OP_OFFER || flags->opmode == OP_REQUEST)
 						&& flags->rtcp_mux_require)))
@@ -2560,7 +2560,7 @@ struct packet_stream *print_rtcp(GString *s, struct call_media *media, GList *rt
 			g_string_append(s, "a=rtcp-mux\r\n");
 			ps_rtcp = NULL;
 		}
-		else if (ps_rtcp && flags->ice_option != ICE_FORCE_RELAY) {
+		else if (ps_rtcp && (!flags || flags->ice_option != ICE_FORCE_RELAY)) {
 			insert_rtcp_attr(s, ps_rtcp, flags);
 			if (MEDIA_ISSET(media, RTCP_MUX))
 				g_string_append(s, "a=rtcp-mux\r\n");