linux-crypto.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Eric Biggers <ebiggers@kernel.org>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
	gregkh@linuxfoundation.org, herbert@gondor.apana.org.au,
	Emil Renner Berthing <kernel@esmil.dk>,
	Ard Biesheuvel <ardb@kernel.org>,
	stable@vger.kernel.org
Subject: Re: [PATCH URGENT crypto v2] crypto: arm64/chacha - correctly walk through blocks
Date: Thu, 19 Mar 2020 12:03:04 -0700	[thread overview]
Message-ID: <20200319190304.GB86395@gmail.com> (raw)
In-Reply-To: <20200319022732.166085-1-Jason@zx2c4.com>

On Wed, Mar 18, 2020 at 08:27:32PM -0600, Jason A. Donenfeld wrote:
> Prior, passing in chunks of 2, 3, or 4, followed by any additional
> chunks would result in the chacha state counter getting out of sync,
> resulting in incorrect encryption/decryption, which is a pretty nasty
> crypto vuln: "why do images look weird on webpages?" WireGuard users
> never experienced this prior, because we have always, out of tree, used
> a different crypto library, until the recent Frankenzinc addition. This
> commit fixes the issue by advancing the pointers and state counter by
> the actual size processed. It also fixes up a bug in the (optional,
> costly) stride test that prevented it from running on arm64.
> 
> Fixes: b3aad5bad26a ("crypto: arm64/chacha - expose arm64 ChaCha routine as library function")
> Reported-and-tested-by: Emil Renner Berthing <kernel@esmil.dk>
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: stable@vger.kernel.org # v5.5+
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
>  arch/arm64/crypto/chacha-neon-glue.c   |  8 ++++----
>  lib/crypto/chacha20poly1305-selftest.c | 11 ++++++++---
>  2 files changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm64/crypto/chacha-neon-glue.c b/arch/arm64/crypto/chacha-neon-glue.c
> index c1f9660d104c..37ca3e889848 100644
> --- a/arch/arm64/crypto/chacha-neon-glue.c
> +++ b/arch/arm64/crypto/chacha-neon-glue.c
> @@ -55,10 +55,10 @@ static void chacha_doneon(u32 *state, u8 *dst, const u8 *src,
>  			break;
>  		}
>  		chacha_4block_xor_neon(state, dst, src, nrounds, l);
> -		bytes -= CHACHA_BLOCK_SIZE * 5;
> -		src += CHACHA_BLOCK_SIZE * 5;
> -		dst += CHACHA_BLOCK_SIZE * 5;
> -		state[12] += 5;
> +		bytes -= l;
> +		src += l;
> +		dst += l;
> +		state[12] += DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE);
>  	}
>  }
>  
> diff --git a/lib/crypto/chacha20poly1305-selftest.c b/lib/crypto/chacha20poly1305-selftest.c
> index c391a91364e9..fa43deda2660 100644
> --- a/lib/crypto/chacha20poly1305-selftest.c
> +++ b/lib/crypto/chacha20poly1305-selftest.c
> @@ -9028,10 +9028,15 @@ bool __init chacha20poly1305_selftest(void)
>  	     && total_len <= 1 << 10; ++total_len) {
>  		for (i = 0; i <= total_len; ++i) {
>  			for (j = i; j <= total_len; ++j) {
> +				k = 0;
>  				sg_init_table(sg_src, 3);
> -				sg_set_buf(&sg_src[0], input, i);
> -				sg_set_buf(&sg_src[1], input + i, j - i);
> -				sg_set_buf(&sg_src[2], input + j, total_len - j);
> +				if (i)
> +					sg_set_buf(&sg_src[k++], input, i);
> +				if (j - i)
> +					sg_set_buf(&sg_src[k++], input + i, j - i);
> +				if (total_len - j)
> +					sg_set_buf(&sg_src[k++], input + j, total_len - j);
> +				sg_init_marker(sg_src, k);
>  				memset(computed_output, 0, total_len);
>  				memset(input, 0, total_len);
>  

Reviewed-by: Eric Biggers <ebiggers@google.com>

Herbert, can you send this to Linus for 5.6?

- Eric

  parent reply	other threads:[~2020-03-19 19:03 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-18 23:45 [PATCH URGENT crypto] " Jason A. Donenfeld
2020-03-19  0:23 ` Eric Biggers
2020-03-19  0:30   ` Eric Biggers
2020-03-19  1:33   ` Jason A. Donenfeld
2020-03-19  2:27     ` [PATCH URGENT crypto v2] " Jason A. Donenfeld
2020-03-19  3:25       ` Eric Biggers
2020-03-19  4:25         ` Jason A. Donenfeld
2020-03-19  4:36           ` Jason A. Donenfeld
2020-03-19 19:03       ` Eric Biggers [this message]
2020-03-20  3:48       ` Herbert Xu
2020-03-20  4:01         ` Jason A. Donenfeld

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200319190304.GB86395@gmail.com \
    --to=ebiggers@kernel.org \
    --cc=Jason@zx2c4.com \
    --cc=ardb@kernel.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=herbert@gondor.apana.org.au \
    --cc=kernel@esmil.dk \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=stable@vger.kernel.org \
    --subject='Re: [PATCH URGENT crypto v2] crypto: arm64/chacha - correctly walk through blocks' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).