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Commit dbd872a1 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

crypto: chacha20 - Use unaligned access macros when loading key and IV 



The generic ChaCha20 implementation has a cra_alignmask of 3, which
ensures that the key passed into crypto_chacha20_setkey() and the IV
passed into crypto_chacha20_init() are 4-byte aligned.  However, these
functions are also called from the ARM and ARM64 implementations of
ChaCha20, which intentionally do not have a cra_alignmask set.  This is
broken because 32-bit words are being loaded from potentially-unaligned
buffers without the unaligned access macros.

Fix it by using the unaligned access macros when loading the key and IV.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent ecf3220d

crypto/chacha20_generic.c

+6 −10
Original line number Diff line number Diff line
@@ -9,16 +9,12 @@ 
 * (at your option) any later version.

 */



#include <asm/unaligned.h>

#include <crypto/algapi.h>

#include <crypto/chacha20.h>

#include <crypto/internal/skcipher.h>

#include <linux/module.h>



static inline u32 le32_to_cpuvp(const void *p)

{

	return le32_to_cpup(p);

}



static void chacha20_docrypt(u32 *state, u8 *dst, const u8 *src,

			     unsigned int bytes)

{
@@ -53,10 +49,10 @@ void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv) 
	state[9]  = ctx->key[5];

	state[10] = ctx->key[6];

	state[11] = ctx->key[7];

	state[12] = le32_to_cpuvp(iv +  0);

	state[13] = le32_to_cpuvp(iv +  4);

	state[14] = le32_to_cpuvp(iv +  8);

	state[15] = le32_to_cpuvp(iv + 12);

	state[12] = get_unaligned_le32(iv +  0);

	state[13] = get_unaligned_le32(iv +  4);

	state[14] = get_unaligned_le32(iv +  8);

	state[15] = get_unaligned_le32(iv + 12);

}

EXPORT_SYMBOL_GPL(crypto_chacha20_init);
@@ -70,7 +66,7 @@ int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key, 
		return -EINVAL;



	for (i = 0; i < ARRAY_SIZE(ctx->key); i++)

		ctx->key[i] = le32_to_cpuvp(key + i * sizeof(u32));

		ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));



	return 0;

}