Hey Eric, On Wed, Mar 18, 2020 at 6:24 PM Eric Biggers <ebiggers@xxxxxxxxxx> wrote: > Thanks for fixing this! We definitely should get this fix to Linus for 5.6. > But I don't think your description of this bug dating back to 2018 is accurate, > because this bug only affects the new library interface to ChaCha20 which was > added in v5.5. In the "regular" crypto API case, the "walksize" is set to > '5 * CHACHA_BLOCK_SIZE', and chacha_doneon() is guaranteed to be called with a > multiple of '5 * CHACHA_BLOCK_SIZE' except at the end. Thus the code worked > fine with the regular crypto API. Ahhh, that seems correct. > > + state[12] += round_up(l, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE; > > Use DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE)? Duh, oops, thanks. Will send a v2 in a few minutes. By the way, I took a brief look at the other implementations accessible from lib/crypto and I didn't see the same issue over there. But I wouldn't mind an extra pair of eyes, if you want to give it a quick look too. Jason
