From c8cfcb78c65877313cda7bcbace624d3dbd1f3b3 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 18 Mar 2020 20:27:32 -0600 Subject: crypto: arm64/chacha - correctly walk through blocks 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 Cc: Ard Biesheuvel Cc: stable@vger.kernel.org # v5.5+ Signed-off-by: Jason A. Donenfeld Reviewed-by: Eric Biggers Signed-off-by: Herbert Xu --- arch/arm64/crypto/chacha-neon-glue.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'arch') 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); } } -- cgit v1.2.3