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Handle incorrect address in X-Forward-Host headers #393

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Merged
asloobq merged 1 commit into from
Mar 3, 2025
Merged

Handle incorrect address in X-Forward-Host headers #393

asloobq merged 1 commit into from
Mar 3, 2025

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@asloobq
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@asloobq asloobq commented Feb 27, 2025 •
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When the value of X-Forward-Host is invalid, Vertx throws a NPE when trying to get the remote address from the request context. The NPE results in a Http Status code 500. To avoid this and return an appropriate 4xx error, handling this NPE gracefully and continuing request processing.

Exceptions seen in logs as

2025-02-25 13:46:55.859	
	at com.uid2.shared.vertx.RequestCapturingHandler.handle(RequestCapturingHandler.java:31)
	2025-02-25 13:46:55.859	
	at com.uid2.shared.vertx.RequestCapturingHandler.handle(RequestCapturingHandler.java:65)
	2025-02-25 13:46:55.859	
	at io.vertx.ext.web.impl.HttpServerRequestWrapper.remoteAddress(HttpServerRequestWrapper.java:154)
	2025-02-25 13:46:55.859	
	at io.vertx.ext.web.impl.ForwardedParser.remoteAddress(ForwardedParser.java:102)
	2025-02-25 13:46:55.859	
	at io.vertx.ext.web.impl.ForwardedParser.calculate(ForwardedParser.java:122)
	2025-02-25 13:46:55.859	
	at io.vertx.ext.web.impl.ForwardedParser.calculateXForward(ForwardedParser.java:184)
	2025-02-25 13:46:55.859	
	at io.vertx.ext.web.impl.ForwardedParser.setHostAndPort(ForwardedParser.java:199)
	2025-02-25 13:46:55.859	
21:46:55.856 [vert.x-eventloop-thread-17] ERROR c.u.o.vertx.GenericFailureHandler - URL: [/static/js/uid2-esp-0.0.1a.js] - Error response code: [500] - Error: java.lang.NullPointerException: Cannot invoke "io.vertx.core.net.HostAndPort.host()" because "authority" is null

clarkxuyang
clarkxuyang reviewed Feb 27, 2025
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src/main/java/com/uid2/shared/vertx/RequestCapturingHandler.java
try {
SocketAddress remoteAddress = context.request().remoteAddress();
remoteClient = getClientAddress(remoteAddress);
} catch (NullPointerException ex) {
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@clarkxuyang clarkxuyang Feb 27, 2025

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Catching a NullPointerException (NPE) directly is generally not ideal in Java. Instead, it's better to prevent the NPE by checking for null conditions before access

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@asloobq asloobq Mar 3, 2025

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The problem isn't that the return value is null. The NPE is thrown from within the vertx library.

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@clarkxuyang clarkxuyang Mar 3, 2025

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Ignore above, It is actually verx throw the NPE while passing the x-forward header and we have no control over it.

@asloobq asloobq merged commit 0699fa0 into main Mar 3, 2025
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@asloobq asloobq deleted the aaq-UID2-5016-handle-x-forwarded-header-gracefully branch March 3, 2025 18:57
@asloobq asloobq mentioned this pull request Mar 3, 2025
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@clarkxuyang clarkxuyang clarkxuyang approved these changes

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@asloobq @clarkxuyang