timingSafeEqual crashes the process when input is non-Buffer

[ChALkeR]

Opening a public issue after discussion

This only crashes when either the server is already wrongly implemented or when non-typechecked user input ends up in timingSafeEqual, both of which are out of scope from being a security issue by the threat model

This needs several calls (3 are enough, as demonstrated) to trigger

Affects 24.x and 25.x

Refs:

• deps: update V8 to 13.6 #58070
• crypto: make timingSafeEqual faster for Uint8Array #52341
• 50a8527867b0 <- likely caused by this

PoC (run a few times or adjust the numbers if you can't reproduce).
This usually crashes on third invalid call on my machine:

import { timingSafeEqual } from 'node:crypto'

const a = Buffer.from('actual')
const input = ''

let j = 0
for (let i = 0; i < 350_000; i++) {
  timingSafeEqual(a, a) // valid usage

  // Each 70001-th request is invalid (exact number doesn't matter)
  // 5 invalid requests total here, but this usually crashes on 3rd
  if (i % 70_000 === 0) {
    console.log(j++)
    try {
      timingSafeEqual(a, input) // invalid usage, leading to process being terminated
    } catch {
      // error is processed or ignored, doesn't matter
    }
  }
}

Or just

import { timingSafeEqual } from 'node:crypto'

for (let i = 0; i < 50_000; i++) {
  try {
    timingSafeEqual('', '')
  } catch {}
}