fix: verify CID hash before decoding in Block.create#340
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rvagg merged 1 commit intoJun 24, 2026
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Block.create is the verifying block constructor, but it decoded bytes before checking they matched the CID, so the codec parser ran on unverified, potentially untrusted input. Hash and compare first, then delegate decoding to createUnsafe. Valid blocks are unchanged; bytes that do not match the CID are now rejected without ever being decoded, and such input always throws the hash mismatch error rather than possibly a codec error first. Adds a test asserting mismatched, codec-invalid bytes reject with the hash error. Closes multiformats#339 Signed-off-by: tabcat <tabcat00@proton.me>
tabcat
commented
Jun 23, 2026
rvagg
reviewed
Jun 24, 2026
| await assert.isRejected(main.create({ bytes: block.bytes, cid: block2.cid, codec, hasher }), 'CID hash does not match bytes') | ||
| }) | ||
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| it('create verifies the cid hash before decoding the bytes', async () => { |
rvagg
approved these changes
Jun 24, 2026
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🎉 This PR is included in version 14.0.2 🎉 The release is available on: Your semantic-release bot 📦🚀 |
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Block.createis the verifying block constructor, but it decodedbytesbefore checking they matched the CID, so the codec parser ran on unverified, potentially untrusted input.This hashes and compares first, then delegates decoding to
createUnsafe. Valid blocks are unchanged; bytes that don't match the CID are now rejected without ever being decoded, and such input always throws the hash-mismatch error rather than possibly a codec error first.Adds a test asserting mismatched, codec-invalid bytes reject with the hash error (i.e. decode never runs).
Closes #339