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crypto: chacha20 - Fix unaligned access when loading constants 

The four 32-bit constants for the initial state of ChaCha20 were loaded
from a char array which is not guaranteed to have the needed alignment.

Fix it by just assigning the constants directly instead.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers 2017-11-22 11:51:35 -08:00 committed by Herbert Xu
parent c3a5360563
commit ecf3220d88
1 changed files with 4 additions and 6 deletions
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10
crypto/chacha20_generic.c
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@ -41,12 +41,10 @@ static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,
void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv)
{
static const char constant[16] = "expand 32-byte k";
state[0] = le32_to_cpuvp(constant + 0);
state[1] = le32_to_cpuvp(constant + 4);
state[2] = le32_to_cpuvp(constant + 8);
state[3] = le32_to_cpuvp(constant + 12);
state[0] = 0x61707865; /* "expa" */
state[1] = 0x3320646e; /* "nd 3" */
state[2] = 0x79622d32; /* "2-by" */
state[3] = 0x6b206574; /* "te k" */
state[4] = ctx->key[0];
state[5] = ctx->key[1];
state[6] = ctx->key[2];