Avoid int overflow in expiration calculations in MockMvc and FlashMap

FlashMap.startExpirationPeriod(int) and MockMvcWebConnection's cookie
handling both multiplied an int number of seconds by 1000 without
widening to long. Above 2_147_483 seconds (about 24.9 days) the
multiplication overflows to a negative offset, so the computed
expiration time lands in the past.

For FlashMap, a flash map configured through
AbstractFlashMapManager.setFlashMapTimeout(int) with a large timeout is
then treated as expired immediately. For MockMvcWebConnection, a cookie
with a large max-age is removed from the CookieManager instead of being
stored.

This applies the same widening already used for this pattern in
gh-25613.

Closes gh-37208

Signed-off-by: kogun <akogun@gmail.com>

spring-test/src/main/java/org/springframework/test/web/servlet/htmlunit/MockMvcWebConnection.java

@@ -183,7 +183,7 @@ public final class MockMvcWebConnection implements WebConnection {
 	private static Cookie createCookie(jakarta.servlet.http.Cookie cookie) {
 		Date expires = null;
 		if (cookie.getMaxAge() > -1) {
-			expires = new Date(System.currentTimeMillis() + cookie.getMaxAge() * 1000);
+			expires = new Date(System.currentTimeMillis() + cookie.getMaxAge() * 1000L);
 		}
 		BasicClientCookie result = new BasicClientCookie(cookie.getName(), cookie.getValue());
 		result.setDomain(cookie.getDomain());

spring-test/src/test/java/org/springframework/test/web/servlet/htmlunit/MockMvcWebClientBuilderTests.java

@@ -109,6 +109,17 @@ class MockMvcWebClientBuilderTests {
 		assertThat(getResponse(client, "http://localhost/").getContentAsString()).isEqualTo("NA");
 	}
 
+	@Test
+	void cookieWithLargeMaxAgeIsStored() throws Exception {
+		this.mockMvc = MockMvcBuilders.standaloneSetup(new CookieController()).build();
+		WebClient client = MockMvcWebClientBuilder.mockMvcSetup(this.mockMvc).build();
+
+		assertThat(getResponse(client, "http://localhost/").getContentAsString()).isEqualTo("NA");
+		assertThat(postResponse(client, "http://localhost/long-lived", "cookie=foo")
+				.getContentAsString()).isEqualTo("Set");
+		assertThat(getResponse(client, "http://localhost/").getContentAsString()).isEqualTo("foo");
+	}
+
 	private void assertMockMvcUsed(WebClient client, String url) throws Exception {
 		assertThat(getResponse(client, url).getContentAsString()).isEqualTo("mvc");
 	}
@@ -162,6 +173,15 @@ class MockMvcWebClientBuilderTests {
 			return "Set";
 		}
 
+		@PostMapping(path = "/long-lived", produces = "text/plain")
+		String setLongLivedCookie(@RequestParam String cookie, HttpServletResponse response) {
+			jakarta.servlet.http.Cookie longLived = new jakarta.servlet.http.Cookie(COOKIE_NAME, cookie);
+			longLived.setMaxAge(Integer.MAX_VALUE);
+			longLived.setPath("/");
+			response.addCookie(longLived);
+			return "Set";
+		}
+
 		@DeleteMapping(path = "/", produces = "text/plain")
 		String deleteCookie(HttpServletResponse response) {
 			jakarta.servlet.http.Cookie cookie = new jakarta.servlet.http.Cookie(COOKIE_NAME, "");

spring-webmvc/src/main/java/org/springframework/web/servlet/FlashMap.java

@@ -112,7 +112,7 @@ public final class FlashMap extends HashMap<String, Object> implements Comparabl
 	 * @param timeToLive the number of seconds before expiration
 	 */
 	public void startExpirationPeriod(int timeToLive) {
-		this.expirationTime = System.currentTimeMillis() + timeToLive * 1000;
+		this.expirationTime = System.currentTimeMillis() + timeToLive * 1000L;
 	}
 
 	/**

spring-webmvc/src/test/java/org/springframework/web/servlet/FlashMapTests.java

@@ -50,6 +50,15 @@ class FlashMapTests {
 		assertThat(flashMap.isExpired()).isFalse();
 	}
 
+	@Test
+	void notExpiredWithLargeTimeToLive() {
+		FlashMap flashMap = new FlashMap();
+		flashMap.startExpirationPeriod(Integer.MAX_VALUE);
+
+		assertThat(flashMap.getExpirationTime()).isGreaterThan(System.currentTimeMillis());
+		assertThat(flashMap.isExpired()).isFalse();
+	}
+
 	@Test
 	void compareTo() {
 		FlashMap flashMap1 = new FlashMap();