Handle undersized data blocks in framed stream decompression#147
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Motivation ---------- A malformed block in the framed stream format can cause an infinite loop when decompressing the stream. This could be used for a DoS attack if an attacker can control the data. Modifications ------------- Short-circuit with an InvalidDataException if the block runs out of data before the decompressor has reached the end of the block. Resolves GHSA-pggp-6c3x-2xmx
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Pull request overview
This PR hardens framed Snappy stream decompression against malformed compressed chunks that can otherwise cause non-terminating behavior (DoS risk) by adding an explicit invalid-data short-circuit and a regression test.
Changes:
- Add an
InvalidDataExceptionguard when a compressed chunk has no remaining bytes but the decompressor still requires input. - Add a test case reproducing the malformed framed-input scenario referenced by the security advisory.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| Snappier/Internal/SnappyStreamDecompressor.cs | Throws InvalidDataException when a compressed framed chunk is exhausted while the decompressor still needs data. |
| Snappier.Tests/SnappyStreamTests.cs | Adds a regression test ensuring malformed framed input throws rather than looping. |
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
This was referenced May 8, 2026
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Motivation
A malformed block in the framed stream format can cause an infinite loop when decompressing the stream. This could be used for a DoS attack if an attacker can control the data.
Modifications
Short-circuit with an InvalidDataException if the block runs out of data before the decompressor has reached the end of the block.