linux-crypto.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org,
	gregkh@linuxfoundation.org, herbert@gondor.apana.org.au
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>,
	Emil Renner Berthing <kernel@esmil.dk>,
	Ard Biesheuvel <ardb@kernel.org>,
	stable@vger.kernel.org
Subject: [PATCH URGENT crypto] crypto: arm64/chacha - correctly walk through blocks
Date: Wed, 18 Mar 2020 17:45:18 -0600	[thread overview]
Message-ID: <20200318234518.83906-1-Jason@zx2c4.com> (raw)

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, dating back to 2018. 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.

Fixes: f2ca1cbd0fb5 ("crypto: arm64/chacha - optimize for arbitrary length inputs")
Reported-and-tested-by: Emil Renner Berthing <kernel@esmil.dk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: stable@vger.kernel.org
---
 arch/arm64/crypto/chacha-neon-glue.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/crypto/chacha-neon-glue.c b/arch/arm64/crypto/chacha-neon-glue.c
index c1f9660d104c..debb1de0d3dd 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] += round_up(l, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE;
 	}
 }
 
-- 
2.25.1


             reply	other threads:[~2020-03-18 23:45 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-18 23:45 Jason A. Donenfeld [this message]
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
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=20200318234518.83906-1-Jason@zx2c4.com \
    --to=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] 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).