Copy MockHttpServletRequest changes to spring-web

See gh-24916

Author: sbrannen

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

spring-web/src/testFixtures/java/org/springframework/web/testfixture/servlet/MockHttpServletRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -668,11 +668,14 @@ public void setServerName(String serverName) {
 
 	@Override
 	public String getServerName() {
-		String host = getHeader(HttpHeaders.HOST);
+		String rawHostHeader = getHeader(HttpHeaders.HOST);
+		String host = rawHostHeader;
 		if (host != null) {
 			host = host.trim();
 			if (host.startsWith("[")) {
-				host = host.substring(1, host.indexOf(']'));
+				int indexOfClosingBracket = host.indexOf(']');
+				Assert.state(indexOfClosingBracket > -1, () -> "Invalid Host header: " + rawHostHeader);
+				host = host.substring(0, indexOfClosingBracket + 1);
 			}
 			else if (host.contains(":")) {
 				host = host.substring(0, host.indexOf(':'));
@@ -690,12 +693,15 @@ public void setServerPort(int serverPort) {
 
 	@Override
 	public int getServerPort() {
-		String host = getHeader(HttpHeaders.HOST);
+		String rawHostHeader = getHeader(HttpHeaders.HOST);
+		String host = rawHostHeader;
 		if (host != null) {
 			host = host.trim();
 			int idx;
 			if (host.startsWith("[")) {
-				idx = host.indexOf(':', host.indexOf(']'));
+				int indexOfClosingBracket = host.indexOf(']');
+				Assert.state(indexOfClosingBracket > -1, () -> "Invalid Host header: " + rawHostHeader);
+				idx = host.indexOf(':', indexOfClosingBracket);
 			}
 			else {
 				idx = host.indexOf(':');