Use InetSocketAddress#getHostString

Sometimes InetSocketAddress#getAddress#getHostAddress retuns null.
In that case, call InetSocketAddress#getHostString instead.

There is no performance loss since IpAddressMatcher#matches attemptsi
to re-parse and resolve the address anyway.

Closes gh-11888

Author: dsbecker

web/src/main/java/org/springframework/security/web/server/util/matcher/IpAddressServerWebExchangeMatcher.java

@@ -48,7 +48,7 @@ public IpAddressServerWebExchangeMatcher(String ipAddress) {
 	public Mono<MatchResult> matches(ServerWebExchange exchange) {
 		// @formatter:off
 		return Mono.justOrEmpty(exchange.getRequest().getRemoteAddress())
-				.map((remoteAddress) -> remoteAddress.getAddress().getHostAddress())
+				.map((remoteAddress) -> remoteAddress.isUnresolved() ? remoteAddress.getHostString() : remoteAddress.getAddress().getHostAddress())
 				.map(this.ipAddressMatcher::matches)
 				.flatMap((matches) -> matches ? MatchResult.match() : MatchResult.notMatch())
 				.switchIfEmpty(MatchResult.notMatch());

web/src/test/java/org/springframework/security/web/server/util/matcher/IpAddressServerWebExchangeMatcherTests.java

@@ -101,6 +101,22 @@ public void matchesWhenZeroMaskAndAnythingThenTrue() throws UnknownHostException
 		assertThat(matcher.matches(exchange("192.168.0.159")).block().isMatch()).isTrue();
 	}
 
+	@Test
+	public void matchesWhenIpv4UnresolvedThenTrue() throws UnknownHostException {
+		ServerWebExchange ipv4Exchange = exchange("192.168.1.104", true);
+		ServerWebExchangeMatcher.MatchResult matches = new IpAddressServerWebExchangeMatcher("192.168.1.104")
+				.matches(ipv4Exchange).block();
+		assertThat(matches.isMatch()).isTrue();
+	}
+
+	@Test
+	public void matchesWhenIpv6UnresolvedThenTrue() throws UnknownHostException {
+		ServerWebExchange ipv6Exchange = exchange("fe80::21f:5bff:fe33:bd68", true);
+		ServerWebExchangeMatcher.MatchResult matches = new IpAddressServerWebExchangeMatcher("fe80::21f:5bff:fe33:bd68")
+				.matches(ipv6Exchange).block();
+		assertThat(matches.isMatch()).isTrue();
+	}
+
 	@Test
 	public void constructorWhenIpv4AddressMaskTooLongThenIllegalArgumentException() {
 		String ipv4AddressWithTooLongMask = "192.168.1.104/33";
@@ -119,8 +135,14 @@ public void constructorWhenIpv6AddressMaskTooLongThenIllegalArgumentException()
 	}
 
 	private static ServerWebExchange exchange(String ipAddress) throws UnknownHostException {
+		return exchange(ipAddress, false);
+	}
+
+	private static ServerWebExchange exchange(String ipAddress, boolean unresolved) throws UnknownHostException {
 		return MockServerWebExchange.builder(MockServerHttpRequest.get("/")
-				.remoteAddress(new InetSocketAddress(InetAddress.getByName(ipAddress), 8080))).build();
+				.remoteAddress(unresolved ? InetSocketAddress.createUnresolved(ipAddress, 8080)
+						: new InetSocketAddress(InetAddress.getByName(ipAddress), 8080)))
+				.build();
 	}
 
 }