Fix frontend uniqueness check, where IP=* is a NULL pointer

Fixes #317

src/configuration.c

@@ -745,16 +745,32 @@ static int
 check_frontend_uniqueness(struct front_arg *cur_fa, hitch_config *cfg)
 {
 	struct front_arg *fa, *fatmp;
+	int retval = 1;
+
 	HASH_ITER(hh, cfg->LISTEN_ARGS, fa, fatmp) {
-		if ((cur_fa->ip == NULL || strcmp(cur_fa->ip, fa->ip) == 0) &&
+		if (cur_fa->ip == NULL && fa->ip == NULL &&
 		    strcmp(cur_fa->port, fa->port) == 0) {
-			config_error_set("Redundant frontend "
-			"(matching IP and port) definition: '%s:%s'.",
-			    fa->ip, fa->port);
-			return (0);
+			retval = 0;
+			break;
+		}
+		else if (cur_fa->ip == NULL || fa->ip == NULL)
+			continue;
+		else {
+			if (strcmp(cur_fa->ip, fa->ip) == 0 &&
+			    strcmp(cur_fa->port, fa->port) == 0) {
+				retval = 0;
+				break;
+			}
 		}
 	}
-	return(1);
+
+	if (retval == 0) {
+		config_error_set("Redundant frontend "
+		    "(matching IP and port) definition: '%s:%s'.",
+		    fa->ip, fa->port);
+	}
+
+	return(retval);
 }
 
 int

src/tests/test34-unique-fa.sh

@@ -0,0 +1,70 @@
+#!/bin/sh
+# Test check_frontend_uniqueness
+. hitch_test.sh
+
+GRP=$(id -gn nobody) ||
+skip 'no usable group found for user nobody'
+
+test_cfg() {
+	cfg=$1.cfg
+	shift
+	cat >"$cfg"
+	run_cmd "$@" hitch \
+		--test \
+		--config="$cfg" \
+		"${CERTSDIR}/default.example.com"
+}
+
+test_bad_cfg() {
+	test_cfg "$1" -s 1
+}
+
+
+test_bad_cfg bad1  <<EOF
+frontend = {
+host = "*"
+port = "443"
+}
+
+frontend = {
+host = "*"
+port = "443"
+}
+EOF
+
+test_bad_cfg bad2  <<EOF
+frontend = {
+host = "*"
+port = "443"
+}
+
+frontend = {
+host = "fd22:5979:45f3:9471::1"
+port = "443"
+}
+EOF
+
+test_cfg bad3  <<EOF
+frontend = {
+host = "fd22:5979:45f3:9471::1"
+port = "443"
+}
+
+frontend = {
+host = "fd22:5979:45f3:9471::1"
+port = "443"
+}
+EOF
+
+test_cfg good1  <<EOF
+frontend = {
+host = "fd22:5979:45f3:9471::1"
+port = "443"
+}
+
+frontend = {
+host = "fd22:5979:45f3:9471::1"
+port = "444"
+}
+EOF
+