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TEZ-4742: AMWebController CORS: only reflect Origin when it matches configured Tez UI base URL #528

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Merged
abstractdog merged 1 commit into from
Jul 21, 2026
+36 −17
Merged

TEZ-4742: AMWebController CORS: only reflect Origin when it matches configured Tez UI base URL #528

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35 changes: 22 additions & 13 deletions tez-dag/src/main/java/org/apache/tez/dag/app/web/AMWebController.java
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Original file line number Diff line number Diff line change
Expand Up @@ -132,27 +132,36 @@ static String encodeHeader(final String header) {
}

@VisibleForTesting
public void setCorsHeaders() {
final HttpServletResponse res = response();

/*
* ideally the Origin and other CORS headers should be checked and response headers set only
* if it matches the allowed origins. however rm does not forward these headers.
*/
String getTrustedOrigin() {
String historyUrlBase = appContext.getAMConf().get(TezConfiguration.TEZ_HISTORY_URL_BASE, "");
String origin = request().getHeader(ORIGIN);
if(origin == null) {
if (!historyUrlBase.isEmpty()) {
try {
URL url = URI.create(historyUrlBase).toURL();
origin = url.getProtocol() + "://" + url.getAuthority();
return url.getProtocol() + "://" + url.getAuthority();
} catch (IllegalArgumentException | MalformedURLException e) {
LOG.debug("Invalid url set for tez history url base: {}", historyUrlBase, e);
}
}
Comment on lines +137 to 144

@abstractdog abstractdog Jul 21, 2026

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maybe refactor this to a method that derives the origin or returns null

return null;
}

if (origin != null) {
origin = encodeHeader(origin);
res.setHeader(ACCESS_CONTROL_ALLOW_ORIGIN, origin);
@VisibleForTesting
public void setCorsHeaders() {
final HttpServletResponse res = response();
String trustedOrigin = getTrustedOrigin();
String requestOrigin = request().getHeader(ORIGIN);

// We cannot blindly reflect the request origin in the Access-Control-Allow-Origin header
// because it would allow malicious sites to bypass CORS and access sensitive data,
// effectively defeating the purpose of CORS. We must strictly validate the request origin
// against the configured, trusted Tez UI base URL before reflecting it.
if (trustedOrigin != null) {
if (requestOrigin == null || requestOrigin.equals(trustedOrigin)) {
res.setHeader(ACCESS_CONTROL_ALLOW_ORIGIN, encodeHeader(trustedOrigin));
Comment on lines +159 to +160

@abstractdog abstractdog Jul 21, 2026 •
edited
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make a code comment above this for "educational purposes" regarding why we cannot reflect the request origin without checking the server's trusted origin, as this is the core of this fix

} else {
LOG.debug("CORS validation failed: request origin {} does not match configured Tez UI base URL {}",
requestOrigin, trustedOrigin);
}
}
res.setHeader(ACCESS_CONTROL_ALLOW_METHODS, ALLOWED_METHODS);
res.setHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS, Boolean.TRUE.toString());
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18 changes: 14 additions & 4 deletions tez-dag/src/test/java/org/apache/tez/dag/app/web/TestAMWebController.java
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,10 @@
import static org.mockito.Mockito.doReturn;
import static org.mockito.Mockito.eq;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.reset;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

Expand Down Expand Up @@ -121,15 +123,23 @@ public void testCorsHeadersWithOrigin() {
AMWebController amWebController = new AMWebController(mockRequestContext, mockAppContext,
"TEST_HISTORY_URL");
AMWebController spy = spy(amWebController);
String originURL = "http://origin.com:8080";
String validOrigin = "http://uihost:9001";
String invalidOrigin = "http://origin.com:8080";

doReturn(mockResponse).when(spy).response();

doReturn(mockRequest).when(spy).request();
doReturn(originURL).when(mockRequest).getHeader(AMWebController.ORIGIN);

// Test 1: Valid origin that matches the configured TEZ_HISTORY_URL_BASE
doReturn(validOrigin).when(mockRequest).getHeader(AMWebController.ORIGIN);
spy.setCorsHeaders();
verify(mockResponse, times(1)).setHeader("Access-Control-Allow-Origin", validOrigin);

// Test 2: Invalid origin that does not match
reset(mockResponse); // Reset the mock to clear the previous invocations
doReturn(invalidOrigin).when(mockRequest).getHeader(AMWebController.ORIGIN);
spy.setCorsHeaders();
verify(mockResponse).setHeader("Access-Control-Allow-Origin", originURL);
// The header should NOT be set because the origin is invalid
verify(mockResponse, never()).setHeader(eq("Access-Control-Allow-Origin"), anyString());
}

@Test
Expand Down
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