Fix Content-Length buffer overflow and add regression tests#45371
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- Add content_length_end == -1 guard to prevent length underflow - Add value_len <= 0 guard to reject malformed headers - Clamp copyOut to min(value_len, sizeof(len)-1) to prevent overflow - Replace std::atoi with absl::SimpleAtoi into uint32_t to reject negative, non-numeric, and out-of-range values - Add regression tests: DecodeOverlongContentLengthDoesNotOverflow, DecodeNegativeContentLengthIsRejected Signed-off-by: Lucy <Asherdardenkol@proton.me>
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Thanks. Just a small suggestion to use string_view instead of copying data.
/wait
| // handful of digits, so clamping cannot turn a legitimate value into a | ||
| // smaller-but-valid number (an over-long value is rejected by the parse | ||
| // below as out of range). | ||
| char len[16] = {}; // zero-initialized, so always NUL terminated after copy |
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Creating absl::string_view into the content, instead of copying may be better. It will also avoid constructing absl::string_view later on.
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Summary
Stack buffer overflow in
Decoder::reassemble()— theContent-Lengthheader value was copied into a fixed-size stack buffer with no length
check, allowing attacker-controlled input to overflow the buffer pre-auth.
Reported via GHSA-rh3p-qxp2-vx3f.
Root cause
contrib/sip_proxy/filters/network/source/decoder.ccpassed anattacker-controlled length directly to
copyOut()without bounds checking:Changes
content_length_end == -1guard to prevent length underflowvalue_len <= 0guard to reject malformed empty/zero-span headersmin(value_len, sizeof(len) - 1)—copyOutcan nolonger write past the buffer
std::atoiwithabsl::SimpleAtoiintouint32_t— rejectsnegative, non-numeric, and out-of-range values
@abseil-cpp//absl/stringstodecoder_libDecodeOverlongContentLengthDoesNotOverflow,DecodeNegativeContentLengthIsRejectedTesting
Not compiled on Windows — verified by review and against the buffer API
contract. Linux build target:
//contrib/sip_proxy/filters/network/test:decoder_test