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Subject[PATCH 1/5] crypto: chacha20 - Fix unaligned access when loading constants
Date
From: Eric Biggers <ebiggers@google.com>

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>
---
crypto/chacha20_generic.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/crypto/chacha20_generic.c b/crypto/chacha20_generic.c
index 4a45fa4890c0..ec84e7837aac 100644
--- a/crypto/chacha20_generic.c
+++ b/crypto/chacha20_generic.c
@@ -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];
--
2.15.0.448.gf294e3d99a-goog
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