Stream protocol: fix a crash in parse_command/1 on zero-size frames (backport #15703)#15709
Merged
the-mikedavis merged 2 commits intov4.2.xfrom Mar 11, 2026
Merged
Stream protocol: fix a crash in parse_command/1 on zero-size frames (backport #15703)#15709the-mikedavis merged 2 commits intov4.2.xfrom
parse_command/1 on zero-size frames (backport #15703)#15709the-mikedavis merged 2 commits intov4.2.xfrom
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A zero-size frame (a 4-byte header with value 0) causes `parse_command/1` to be called with an empty binary `<<>>`, for which no clause matches, crashing the stream connection process. Add a test case that reproduces the crash by sending the exact 8-byte payload observed in production logs from EC2-hosted brokers. (cherry picked from commit 2453561)
When a client sends a zero-size frame (e.g. a port scanner sending
`<<0,0,0,0,0,0,0,0>>`), `parse_command/1` is called with an empty
binary `<<>>`. No existing clause matches, causing a `function_clause`
crash that terminates the stream connection process.
Add a catch-all clause that returns `{unknown, Data}` for any binary
that is not a valid request or response frame. This is already a valid
`command()` type and is handled gracefully by all three frame handlers
in `rabbit_stream_reader`: pre-auth closes the connection, post-auth
sends a protocol-level close frame, and post-close ignores it.
(cherry picked from commit 3510476)
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When a client sends a zero-size frame — for example, a port scanner sending
<<0,0,0,0,0,0,0,0>>to the TLS-enabled stream listeners port,parse_command/1is called with an empty binary<<>>. No existing clause matches, causing afunction_clausecrash that terminates the stream connection process. This has been observed consistently on EC2-hosted brokers.Add a catch-all clause that returns
{unknown, Data}for any binary that is not a valid request or response frame.{unknown, binary()}is already a validcommand()type and is handled gracefully by all three frame handlers inrabbit_stream_reader: pre-auth closes the connection, post-auth sends a protocol-level close frame withRESPONSE_CODE_UNKNOWN_FRAME, and post-close ignores it.The fix is accompanied by a test that reproduces the exact crash using the 8-byte payload observed in production logs.
This is an automatic backport of pull request #15703 done by [Mergify](https://mergify.com).