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HPACK decode failures must be treated as connection errors (COMPRESSION_ERROR) #625

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Merged
arturobernalg merged 1 commit into from
Feb 18, 2026
+125 −4
Merged

HPACK decode failures must be treated as connection errors (COMPRESSION_ERROR) #625

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23 changes: 20 additions & 3 deletions ...ore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/AbstractH2StreamMultiplexer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,8 @@
import org.apache.hc.core5.http2.frame.StreamIdGenerator;
import org.apache.hc.core5.http2.hpack.HPackDecoder;
import org.apache.hc.core5.http2.hpack.HPackEncoder;
import org.apache.hc.core5.http2.hpack.HPackException;
import org.apache.hc.core5.http2.hpack.HeaderListConstraintException;
import org.apache.hc.core5.http2.impl.BasicH2TransportMetrics;
import org.apache.hc.core5.http2.nio.AsyncPingHandler;
import org.apache.hc.core5.http2.nio.command.PingCommand;
Expand Down Expand Up @@ -1114,7 +1116,7 @@ private void consumePushPromiseFrame(final RawFrame frame, final ByteBuffer payl
localConfig.getMaxContinuations());
}
if (continuation == null) {
final List<Header> headers = hPackDecoder.decodeHeaders(payload);
final List<Header> headers = decodeHeaders(payload);
if (streamListener != null) {
streamListener.onHeaderInput(this, promisedStreamId, headers);
}
Expand All @@ -1124,8 +1126,23 @@ private void consumePushPromiseFrame(final RawFrame frame, final ByteBuffer payl
}
}

List<Header> decodeHeaders(final ByteBuffer payload) throws HttpException {
return hPackDecoder.decodeHeaders(payload);
List<Header> decodeHeaders(final ByteBuffer payload) throws HttpException, IOException {
try {
return hPackDecoder.decodeHeaders(payload);
} catch (final HeaderListConstraintException ex) {
// Not a decoding failure; allow upper layers to map (server maps to 431).
throw ex;
} catch (final HPackException ex) {
final H2ConnectionException connEx =
new H2ConnectionException(H2Error.COMPRESSION_ERROR, ex.getMessage());
connEx.initCause(ex);
throw connEx;
} catch (final IllegalArgumentException ex) {
// Decoder invariant violation during HPACK parsing -> treat as decoding failure.
final H2ConnectionException connEx = new H2ConnectionException(H2Error.COMPRESSION_ERROR, ex.getMessage());
connEx.initCause(ex);
throw connEx;
}
}

private void consumeHeaderFrame(final RawFrame frame, final H2Stream stream) throws HttpException, IOException {
Expand Down
2 changes: 1 addition & 1 deletion httpcore5-h2/src/main/java/org/apache/hc/core5/http2/impl/nio/ServerH2StreamMultiplexer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -154,7 +154,7 @@ boolean allowGracefulAbort(final H2Stream stream) {
}

@Override
List<Header> decodeHeaders(final ByteBuffer payload) throws HttpException {
List<Header> decodeHeaders(final ByteBuffer payload) throws HttpException, IOException {
try {
return super.decodeHeaders(payload);
} catch (final HeaderListConstraintException ex) {
Expand Down
104 changes: 104 additions & 0 deletions ...-h2/src/test/java/org/apache/hc/core5/http2/impl/nio/TestAbstractH2StreamMultiplexer.java
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Expand Up @@ -67,6 +67,7 @@
import org.apache.hc.core5.http2.frame.RawFrame;
import org.apache.hc.core5.http2.frame.StreamIdGenerator;
import org.apache.hc.core5.http2.hpack.HPackEncoder;
import org.apache.hc.core5.http2.hpack.HPackException;
import org.apache.hc.core5.reactor.ProtocolIOSession;
import org.apache.hc.core5.util.ByteArrayBuffer;
import org.apache.hc.core5.util.Timeout;
Expand Down Expand Up @@ -1435,5 +1436,108 @@ private static void makeMuxIdle(final AbstractH2StreamMultiplexer mux, final Tim
setLastActivityTime(mux, System.currentTimeMillis() - effectiveMillis - 10);
}

@Test
void testHpackDecodeFailureInHeadersCausesConnectionCompressionError() throws Exception {
final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
protocolIOSession,
FRAME_FACTORY,
StreamIdGenerator.ODD, // peer-initiated streams are EVEN (e.g. 2)
httpProcessor,
CharCodingConfig.DEFAULT,
H2Config.custom().build(),
h2StreamListener,
() -> streamHandler);

final WritableByteChannelMock writableChannel = new WritableByteChannelMock(256);
final FrameOutputBuffer outBuffer = new FrameOutputBuffer(16 * 1024);

// Invalid HPACK: indexed header field representation with index = 0 (illegal).
final byte[] invalidHeaderBlock = new byte[] { (byte) 0x80 };

final RawFrame headersFrame = FRAME_FACTORY.createHeaders(
2,
ByteBuffer.wrap(invalidHeaderBlock),
true, // END_HEADERS
false);

outBuffer.write(headersFrame, writableChannel);

final H2ConnectionException exception = Assertions.assertThrows(H2ConnectionException.class, () ->
mux.onInput(ByteBuffer.wrap(writableChannel.toByteArray())));

Assertions.assertEquals(H2Error.COMPRESSION_ERROR, H2Error.getByCode(exception.getCode()));

// Must not be delegated to stream-level handlers.
Mockito.verify(streamHandler, Mockito.never())
.consumeHeader(ArgumentMatchers.anyList(), ArgumentMatchers.anyBoolean());
Mockito.verify(streamHandler, Mockito.never())
.handle(ArgumentMatchers.any(HttpException.class), ArgumentMatchers.anyBoolean());
Mockito.verify(streamHandler, Mockito.never())
.failed(ArgumentMatchers.any(Exception.class));
}

@Test
void testHpackDecodeFailureInPushPromiseCausesConnectionCompressionError() throws Exception {
final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
protocolIOSession,
FRAME_FACTORY,
StreamIdGenerator.ODD,
httpProcessor,
CharCodingConfig.DEFAULT,
H2Config.custom().setPushEnabled(true).build(),
h2StreamListener,
() -> streamHandler);

// Create an existing local stream (client-initiated, odd) that can receive PUSH_PROMISE.
final H2StreamChannel channel = mux.createChannel(1);
mux.createStream(channel, streamHandler);

final ByteBuffer payload = ByteBuffer.allocate(5);
payload.putInt(2); // promised stream id (peer/server uses even)
}

@Test
void testHpackExceptionInHeadersMappedToConnectionCompressionError() throws Exception {
final AbstractH2StreamMultiplexer mux = new H2StreamMultiplexerImpl(
protocolIOSession,
FRAME_FACTORY,
StreamIdGenerator.ODD,
httpProcessor,
CharCodingConfig.DEFAULT,
H2Config.custom().build(),
h2StreamListener,
() -> streamHandler);

final WritableByteChannelMock writableChannel = new WritableByteChannelMock(256);
final FrameOutputBuffer outBuffer = new FrameOutputBuffer(16 * 1024);

// HPACK: literal header field with incremental indexing (0x40), "new name".
// Next byte is the name string length (here: 10), but we provide no bytes -> truncated.
// This should throw HPackException.
final byte[] invalidHeaderBlock = new byte[] { (byte) 0x40, (byte) 0x0a };

final RawFrame headersFrame = FRAME_FACTORY.createHeaders(
2,
ByteBuffer.wrap(invalidHeaderBlock),
true, // END_HEADERS
false);

outBuffer.write(headersFrame, writableChannel);

final H2ConnectionException ex = Assertions.assertThrows(H2ConnectionException.class, () ->
mux.onInput(ByteBuffer.wrap(writableChannel.toByteArray())));

Assertions.assertEquals(H2Error.COMPRESSION_ERROR, H2Error.getByCode(ex.getCode()));
Assertions.assertInstanceOf(HPackException.class, ex.getCause());

// Must not be handled at stream level
Mockito.verify(streamHandler, Mockito.never())
.consumeHeader(ArgumentMatchers.anyList(), ArgumentMatchers.anyBoolean());
Mockito.verify(streamHandler, Mockito.never())
.handle(ArgumentMatchers.any(HttpException.class), ArgumentMatchers.anyBoolean());
Mockito.verify(streamHandler, Mockito.never())
.failed(ArgumentMatchers.any(Exception.class));
}

}

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