UPSTREAM: 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 <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>
(cherry picked from commit c8cfcb78c65877313cda7bcbace624d3dbd1f3b3)
Bug: 152722841
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Change-Id: I5cc490050c552d95c19e3195b2e8e747e3928c00
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Jason A. Donenfeld 2020-03-18 20:27:32 -06:00 • committed by Alexander Martinz
commit 8bd9fc0db2
No known key found for this signature in database
GPG key ID: CF15BDD9A321A9B2
2 changed files with 12 additions and 7 deletions

View file

@ -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);
}
}

View file

@ -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);