ext_proc filter crash when sending trailers when request has no body #27430
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Signed-off-by: Yanjun Xiang <yanjunxiang@google.com>
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/assign @adisuissa @yanavlasov |
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The detail fuzz report could be found here: https://clusterfuzz.corp.google.com/testcase-detail/5547889199546368 The crash traceback decode is: [2023-05-16 15:50:05.109][2540875][info][misc] [test/test_common/test_random_generator.cc:20] TestRandomGenerator running with seed -38107400 [2023-05-16 15:50:05.171][2540875][trace][ext_proc] [source/extensions/filters/http/ext_proc/ext_proc.cc:183] decodeHeaders: end_stream = false [2023-05-16 15:50:05.172][2540875][trace][ext_proc] [source/extensions/filters/http/ext_proc/ext_proc.cc:467] decodeTrailers
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The test case to reproduce the crash is: cat test/extensions/filters/http/ext_proc/unit_test_fuzz/ext_proc_corpus/clusterfuzz-testcase-minimized-ext_proc_unit_test_fuzz-5547889199546368.test |
| @@ -195,7 +195,9 @@ class Filter : public Logger::Loggable<Logger::Id::ext_proc>, | |||
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| void sendBufferedData(ProcessorState& state, ProcessorState::CallbackState new_state, | |||
| bool end_stream) { | |||
| sendBodyChunk(state, *state.bufferedData(), new_state, end_stream); | |||
| if (state.hasBufferedData()) { | |||
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I'm not an expert on ext-proc, so high-level observation.
IIUC the current fix prevents sending a body of length 0 with end_stream. If this is the desired behavior, then I think it is ok.
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Thanks for the comments!
Actually, ext_proc filter supports sending a body of length 0:
This change is causing test failures. So, we changed it into if the no buffered data, then sends an empty body.
After that, we seeing another issue with stream_ pointer as null, so the new change also fixed it. Please check the root cause comments for details.
| @@ -195,7 +195,9 @@ class Filter : public Logger::Loggable<Logger::Id::ext_proc>, | |||
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| void sendBufferedData(ProcessorState& state, ProcessorState::CallbackState new_state, | |||
| bool end_stream) { | |||
| sendBodyChunk(state, *state.bufferedData(), new_state, end_stream); | |||
| if (state.hasBufferedData()) { | |||
| sendBodyChunk(state, *state.bufferedData(), new_state, end_stream); | |||
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Another observation: the call in case of an empty body, will not change the state to new_state. Is this the desired outcome?
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Yeah, that's a good catch. We should send an empty body if no buffered data as in the new diffs.
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@stevenzzzz as an additional pair of eyes |
Signed-off-by: Yanjun Xiang <yanjunxiang@google.com>
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This fuzzer test cases exposed two issues in the ext_proc filter. If the filter processing mode is set into request header: SKIP and request body :BUFFERED, at same time, when the request only contains headers and trailers then it hit two distinct crash:
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/assign @htuch |
Signed-off-by: Yanjun Xiang <yanjunxiang@google.com>
Done! |
…nvoyproxy#27430) * ext_proc filter crash when sending trailers without sending body. Signed-off-by: Yanjun Xiang <yanjunxiang@google.com> Signed-off-by: Ryan Eskin <ryan.eskin89@protonmail.com>
ext_proc filter crash when sending trailers when request has no body.
The code is assuming the request always has body available and stored in the ext_proc buffer state when processing trailers, which leads into the crash.
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