Messages in this thread | | | From | "Jason A. Donenfeld" <> | Date | Wed, 18 Mar 2020 19:33:18 -0600 | Subject | Re: [PATCH URGENT crypto] crypto: arm64/chacha - correctly walk through blocks |
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Hey Eric,
On Wed, Mar 18, 2020 at 6:24 PM Eric Biggers <ebiggers@kernel.org> 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
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