[bitreq] Fix unbounded proxy / body reads#452
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tcharding merged 6 commits intorust-bitcoin:masterfrom Jan 15, 2026
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Fix multiple issues in the sync proxy response reading loop: 1. Use extend_from_slice(&buf[..n]) instead of append(&mut buf) to only append the bytes that were actually read, not the entire buffer 2. Check for EOF (n == 0) to prevent infinite loops when a proxy doesn't close the connection 3. Add MAX_PROXY_RESPONSE_SIZE (16MB) limit to prevent unbounded memory allocation from a malicious/misbehaving proxy 4. Use a stack-allocated buffer instead of allocating a new Vec each iteration Co-Authored-By: Claude AI
Apply the same fixes as the sync version to the async proxy response reading loop: 1. Check for EOF (n == 0) to prevent infinite loops 2. Add MAX_PROXY_RESPONSE_SIZE (16MB) limit to prevent unbounded memory allocation from a malicious/misbehaving proxy 3. Use a stack-allocated buffer instead of allocating a new Vec each iteration Co-Authored-By: Claude AI
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Add a new `with_max_body_size` option to `Request` that limits the maximum response body size. This prevents memory exhaustion attacks where a malicious server returns an infinite or very large body. The default is None (unlimited) for backwards compatibility, but users connecting to untrusted servers should set a limit. Co-Authored-By: Claude AI
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| /// accept. | ||
| /// | ||
| /// If this limit is passed, the request will close the connection | ||
| /// and return an [Error::BodyOverflow] error. |
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Oops, worth noting this does not apply to lazily-loaded requests (or maybe we should make it?)
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The max_body_size limit was previously only enforced when using send() or send_async() which fully load the response body. This change extends the limit to also apply when using send_lazy(), which returns a ResponseLazy that streams the body byte-by-byte. - Add max_body_size and bytes_read fields to ResponseLazy - Pass max_body_size from Connection::send to ResponseLazy::from_stream - Check body size limit in Iterator::next before returning each byte - Return Error::BodyOverflow when limit is exceeded The Read implementation automatically benefits from this since it uses the Iterator implementation internally. Co-Authored-By: HAL 9000
Use saturating_add instead of += when accumulating content_length in chunked transfer encoding. This prevents integer overflow on 32-bit systems where a malicious server could send chunk sizes that cause the accumulated length to wrap around. Co-Authored-By: Claude AI
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TheBlueMatt
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Hey @TheBlueMatt I use the Bitcoin Core merge script ( EDIT: Ah I'm just going to merge so you can rebase #459 |
tcharding
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tcharding
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Will do in the future! |
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Thanks man |
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b9db614 [bitreq] Add a changelog entry for 0.3 (Matt Corallo) 51ffafd [bitreq] Bump crate version to 0.3 (Matt Corallo) bc4f41a [bitreq] Rename `Proxy::new` to `Proxy::new_http` (Matt Corallo) 99acf70 [bitreq] Drop mention port port 1080 which is for SOCKS, not HTTP (Matt Corallo) d69be71 [bitreq] Make `Error` `#[non_exhaustive]` (Matt Corallo) Pull request description: Based on #452 I think its reasonable to release a bitreq 0.3. There's some issues remaining in the proxy code described in #458 but those should be addressable in a point release without API breakage. ACKs for top commit: tcharding: ACK b9db614 Tree-SHA512: 36d4660f2f37104e9e9fa2ded578b9385b23eee966ecf59de630dfb05eddeb4f1421e656bd410666eabe5708b45771ba1aa3ee8d04cc83c142b017c0ce048208
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Asked Claude to fix a few minor issues that might allow a malicious counterparty to send us unbounded data.
(cc @TheBlueMatt)