From 8e03be9f2698f2da9027d40b9e9c0c9429b74dc0 Mon Sep 17 00:00:00 2001
From: Mark Thomas <markt@apache.org>
Date: Thu, 25 Jan 2024 12:13:55 +0000
Subject: [PATCH] Report HTTP/2 header parsing errors earlier

---
 java/org/apache/coyote/http2/Http2Parser.java | 11 ++++++-----
 webapps/docs/changelog.xml                    |  5 +++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/java/org/apache/coyote/http2/Http2Parser.java b/java/org/apache/coyote/http2/Http2Parser.java
index 5053a219bea0..c1f85422273e 100644
--- a/java/org/apache/coyote/http2/Http2Parser.java
+++ b/java/org/apache/coyote/http2/Http2Parser.java
@@ -283,6 +283,9 @@ protected void readHeadersFrame(int streamId, int flags, int payloadSize, ByteBu
 
         swallowPayload(streamId, FrameType.HEADERS.getId(), padLength, true, buffer);
 
+        // Validate the headers so far
+        hpackDecoder.getHeaderEmitter().validateHeaders();
+
         if (Flags.isEndOfHeaders(flags)) {
             onHeadersComplete(streamId);
         } else {
@@ -446,6 +449,9 @@ protected void readContinuationFrame(int streamId, int flags, int payloadSize, B
 
         readHeaderPayload(streamId, payloadSize, buffer);
 
+        // Validate the headers so far
+        hpackDecoder.getHeaderEmitter().validateHeaders();
+
         if (endOfHeaders) {
             headersCurrentStream = -1;
             onHeadersComplete(streamId);
@@ -637,11 +643,6 @@ protected void onHeadersComplete(int streamId) throws Http2Exception {
                     Http2Error.COMPRESSION_ERROR);
         }
 
-        // Delay validation (and triggering any exception) until this point
-        // since all the headers still have to be read if a StreamException is
-        // going to be thrown.
-        hpackDecoder.getHeaderEmitter().validateHeaders();
-
         synchronized (output) {
             output.headersEnd(streamId, headersEndStream);
 
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
index 0aa6868e7083..f6cf372b9a31 100644
--- a/webapps/docs/changelog.xml
+++ b/webapps/docs/changelog.xml
@@ -171,6 +171,11 @@
         <code>Content-Type</code> value to improve performance by reducing
         repeated <code>byte[]</code> to <code>String</code> conversions. (markt)
       </fix>
+      <fix>
+        Improve error reporting to HTTP/2 clients for header processing errors
+        by reporting problems at the end of the frame where the error was
+        detected rather than at the end of the headers. (markt)
+      </fix>
     </changelog>
   </subsection>
   <subsection name="Jasper">