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Fix #9770, last frame may contain extra data that doesn't affect decompression (#9832)

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Motivation:
Client can split data into different numbers of fragments and sometimes the last frame may contain trash data that doesn't affect decompression process.

Modification:
Added check if last frame is `ContinuationWebSocketFrame` and decompression data is empty
then don't throw an exception.

Result:
Fixes #9770
This commit is contained in:
Andrey Mizurov 2019-12-11 17:00:52 +03:00 committed by Norman Maurer
parent 9fa8b02dbd
commit cf63bc1005
2 changed files with 64 additions and 2 deletions
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8
codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/compression/DeflateDecoder.java
View File

@ -136,8 +136,12 @@ abstract class DeflateDecoder extends WebSocketExtensionDecoder {
// Correctly handle empty frames
// See https://github.com/netty/netty/issues/4348
if (!emptyDeflateBlock && readable && compositeDecompressedContent.numComponents() <= 0) {
compositeDecompressedContent.release();
throw new CodecException("cannot read uncompressed buffer");
// Sometimes after fragmentation the last frame
// May contain left-over data that doesn't affect decompression
if (!(msg instanceof ContinuationWebSocketFrame)) {
compositeDecompressedContent.release();
throw new CodecException("cannot read uncompressed buffer");
}
}
if (msg.isFinalFragment() && noContext) {

58
codec-http/src/test/java/io/netty/handler/codec/http/websocketx/extensions/compression/PerMessageDeflateDecoderTest.java
View File

@ -328,4 +328,62 @@ public class PerMessageDeflateDecoderTest {
assertFalse(decoderChannel.finish());
}
@Test
public void testFragmentedFrameWithLeftOverInLastFragment() {
String hexDump = "677170647a777a737574656b707a787a6f6a7561756578756f6b7868616371716c657a6d64697479766d726f6" +
"269746c6376777464776f6f72767a726f64667278676764687775786f6762766d776d706b76697773777a7072" +
"6a6a737279707a7078697a6c69616d7461656d646278626d786f66666e686e776a7a7461746d7a776668776b6" +
"f6f736e73746575637a6d727a7175707a6e74627578687871767771697a71766c64626d78726d6d7675756877" +
"62667963626b687a726d676e646263776e67797264706d6c6863626577616967706a78636a72697464756e627" +
"977616f79736475676f76736f7178746a7a7479626c64636b6b6778637768746c62";
EmbeddedChannel encoderChannel = new EmbeddedChannel(
ZlibCodecFactory.newZlibEncoder(ZlibWrapper.NONE, 9, 15, 8));
EmbeddedChannel decoderChannel = new EmbeddedChannel(new PerMessageDeflateDecoder(false));
ByteBuf originPayload = Unpooled.wrappedBuffer(ByteBufUtil.decodeHexDump(hexDump));
assertTrue(encoderChannel.writeOutbound(originPayload.duplicate().retain()));
ByteBuf compressedPayload = encoderChannel.readOutbound();
compressedPayload = compressedPayload.slice(0, compressedPayload.readableBytes() - 4);
int oneThird = compressedPayload.readableBytes() / 3;
TextWebSocketFrame compressedFrame1 = new TextWebSocketFrame(
false, WebSocketExtension.RSV1, compressedPayload.slice(0, oneThird));
ContinuationWebSocketFrame compressedFrame2 = new ContinuationWebSocketFrame(
false, WebSocketExtension.RSV3, compressedPayload.slice(oneThird, oneThird));
ContinuationWebSocketFrame compressedFrame3 = new ContinuationWebSocketFrame(
false, WebSocketExtension.RSV3, compressedPayload.slice(oneThird * 2, oneThird));
int offset = oneThird * 3;
ContinuationWebSocketFrame compressedFrameWithExtraData = new ContinuationWebSocketFrame(
true, WebSocketExtension.RSV3, compressedPayload.slice(offset,
compressedPayload.readableBytes() - offset));
// check that last fragment contains only one extra byte
assertEquals(1, compressedFrameWithExtraData.content().readableBytes());
assertEquals(1, compressedFrameWithExtraData.content().getByte(0));
// write compressed frames
assertTrue(decoderChannel.writeInbound(compressedFrame1.retain()));
assertTrue(decoderChannel.writeInbound(compressedFrame2.retain()));
assertTrue(decoderChannel.writeInbound(compressedFrame3.retain()));
assertTrue(decoderChannel.writeInbound(compressedFrameWithExtraData));
// read uncompressed frames
TextWebSocketFrame uncompressedFrame1 = decoderChannel.readInbound();
ContinuationWebSocketFrame uncompressedFrame2 = decoderChannel.readInbound();
ContinuationWebSocketFrame uncompressedFrame3 = decoderChannel.readInbound();
ContinuationWebSocketFrame uncompressedExtraData = decoderChannel.readInbound();
assertFalse(uncompressedExtraData.content().isReadable());
ByteBuf uncompressedPayload = Unpooled.wrappedBuffer(uncompressedFrame1.content(), uncompressedFrame2.content(),
uncompressedFrame3.content(), uncompressedExtraData.content());
assertEquals(originPayload, uncompressedPayload);
assertTrue(originPayload.release());
assertTrue(uncompressedPayload.release());
assertTrue(encoderChannel.finishAndReleaseAll());
assertFalse(decoderChannel.finish());
}
}