From: Jason A. Donenfeld Jason@zx2c4.com
commit c8cfcb78c65877313cda7bcbace624d3dbd1f3b3 upstream.
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 Reviewed-by: Eric Biggers ebiggers@google.com Signed-off-by: Herbert Xu herbert@gondor.apana.org.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/crypto/chacha-neon-glue.c | 8 ++++---- lib/crypto/chacha20poly1305-selftest.c | 11 ++++++++--- 2 files changed, 12 insertions(+), 7 deletions(-)
--- 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 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); } }
--- a/lib/crypto/chacha20poly1305-selftest.c +++ b/lib/crypto/chacha20poly1305-selftest.c @@ -9028,10 +9028,15 @@ bool __init chacha20poly1305_selftest(vo && 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);