[tss][cs-6.19]: KeySign Message Hash Is Silently Truncated to Curve Order Major

[byteflyfunny]

The function MsgToHashInt checks for an error condition that cannot occur due to the hardcoded nil error value in the called function. Additionally, the function hashToInt silently truncates the msg[] array (essentially a byte[] hash) to the curve order without any checks to ensure that msg[] is well-formed and within the operational bounds of the function, e.g., a minimum or maximum length. This can lead to undesirable behavior.

[byteflyfunny]

No matter the length of the msg[] is too large, it will always be truncated to a fixed length in the end.
orderBits := c.Params().N.BitLen() orderBytes := (orderBits + 7) / 8 if len(hash) > orderBytes { hash = hash[:orderBytes] }