lestrrat-go/jwx v2.0.16

on GitHub

v2.0.16 31 Oct 2023
[Security]
  * [jws] ECDSA signature verification requires us to check if the signature
    is of the desired length of bytes, but this check that used to exist before
    had been removed in #65, resulting in certain malformed signatures to pass
    verification.

    One of the ways this could happen if R is a 31 byte integer and S is 32 byte integer,
    both containing the correct signature values, but R is not zero-padded.

       Correct = R: [ 0 , ... ] (32 bytes) S: [ ... ] (32 bytes)
       Wrong   = R: [ ... ] (31 bytes)     S: [ ... ] (32 bytes)

    In order for this check to pass, you would still need to have all 63 bytes
    populated with the correct signature. The only modification a bad actor
    may be able to do is to add one more byte at the end, in which case the
    first 32 bytes (including what would have been S's first byte) is used for R,
    and S would contain the rest. But this will only result in the verification to
    fail. Therefore this in itself should not pose any security risk, albeit
    allowing some illegally formated messages to be verified.

  * [jwk] `jwk.Key` objects now have a `Validate()` method to validate the data
    stored in the keys. However, this still does not necessarily mean that the key's
        are valid for use in cryptographic operations. If `Validate()` is successful,
    it only means that the keys are in the right _format_, including the presence
    of required fields and that certain fields have proper length, etc.

[New Features]
  * [jws] Added `jws.WithValidateKey()` to force calling `key.Validate()` before
    signing or verification.

  * [jws] `jws.Sign()` now returns a special type of error that can hold the
    individual errors from the signers. The stringification is still the same
    as before to preserve backwards compatibility.

  * [jwk] Added `jwk.IsKeyValidationError` that checks if an error is an error
    from `key.Validate()`.

[Bug Fixes]
  * [jwt] `jwt.ParseInsecure()` was running verification if you provided a key
    via `jwt.WithKey()` or `jwt.WithKeySet()` (#1007)