Commit e2d60e2f authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Herbert Xu
Browse files

crypto: x86/cast5 - drop CTR mode implementation 



CAST5 in CTR mode is never used by the kernel directly, and is highly
unlikely to be relied upon by dm-crypt or algif_skcipher. So let's drop
the accelerated CTR mode implementation, and instead, rely on the CTR
template and the bare cipher.

Acked-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 2e9440ae

arch/x86/crypto/cast5_avx_glue.c

+0 −103
Original line number Diff line number Diff line
@@ -23,8 +23,6 @@ asmlinkage void cast5_ecb_dec_16way(struct cast5_ctx *ctx, u8 *dst, 
				    const u8 *src);

asmlinkage void cast5_cbc_dec_16way(struct cast5_ctx *ctx, u8 *dst,

				    const u8 *src);

asmlinkage void cast5_ctr_16way(struct cast5_ctx *ctx, u8 *dst, const u8 *src,

				__be64 *iv);



static int cast5_setkey_skcipher(struct crypto_skcipher *tfm, const u8 *key,

				 unsigned int keylen)
@@ -214,92 +212,6 @@ static int cbc_decrypt(struct skcipher_request *req) 
	return err;

}



static void ctr_crypt_final(struct skcipher_walk *walk, struct cast5_ctx *ctx)

{

	u8 *ctrblk = walk->iv;

	u8 keystream[CAST5_BLOCK_SIZE];

	u8 *src = walk->src.virt.addr;

	u8 *dst = walk->dst.virt.addr;

	unsigned int nbytes = walk->nbytes;



	__cast5_encrypt(ctx, keystream, ctrblk);

	crypto_xor_cpy(dst, keystream, src, nbytes);



	crypto_inc(ctrblk, CAST5_BLOCK_SIZE);

}



static unsigned int __ctr_crypt(struct skcipher_walk *walk,

				struct cast5_ctx *ctx)

{

	const unsigned int bsize = CAST5_BLOCK_SIZE;

	unsigned int nbytes = walk->nbytes;

	u64 *src = (u64 *)walk->src.virt.addr;

	u64 *dst = (u64 *)walk->dst.virt.addr;



	/* Process multi-block batch */

	if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {

		do {

			cast5_ctr_16way(ctx, (u8 *)dst, (u8 *)src,

					(__be64 *)walk->iv);



			src += CAST5_PARALLEL_BLOCKS;

			dst += CAST5_PARALLEL_BLOCKS;

			nbytes -= bsize * CAST5_PARALLEL_BLOCKS;

		} while (nbytes >= bsize * CAST5_PARALLEL_BLOCKS);



		if (nbytes < bsize)

			goto done;

	}



	/* Handle leftovers */

	do {

		u64 ctrblk;



		if (dst != src)

			*dst = *src;



		ctrblk = *(u64 *)walk->iv;

		be64_add_cpu((__be64 *)walk->iv, 1);



		__cast5_encrypt(ctx, (u8 *)&ctrblk, (u8 *)&ctrblk);

		*dst ^= ctrblk;



		src += 1;

		dst += 1;

		nbytes -= bsize;

	} while (nbytes >= bsize);



done:

	return nbytes;

}



static int ctr_crypt(struct skcipher_request *req)

{

	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);

	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);

	bool fpu_enabled = false;

	struct skcipher_walk walk;

	unsigned int nbytes;

	int err;



	err = skcipher_walk_virt(&walk, req, false);



	while ((nbytes = walk.nbytes) >= CAST5_BLOCK_SIZE) {

		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);

		nbytes = __ctr_crypt(&walk, ctx);

		err = skcipher_walk_done(&walk, nbytes);

	}



	cast5_fpu_end(fpu_enabled);



	if (walk.nbytes) {

		ctr_crypt_final(&walk, ctx);

		err = skcipher_walk_done(&walk, 0);

	}



	return err;

}



static struct skcipher_alg cast5_algs[] = {

	{

		.base.cra_name		= "__ecb(cast5)",
@@ -328,21 +240,6 @@ static struct skcipher_alg cast5_algs[] = { 
		.setkey			= cast5_setkey_skcipher,

		.encrypt		= cbc_encrypt,

		.decrypt		= cbc_decrypt,

	}, {

		.base.cra_name		= "__ctr(cast5)",

		.base.cra_driver_name	= "__ctr-cast5-avx",

		.base.cra_priority	= 200,

		.base.cra_flags		= CRYPTO_ALG_INTERNAL,

		.base.cra_blocksize	= 1,

		.base.cra_ctxsize	= sizeof(struct cast5_ctx),

		.base.cra_module	= THIS_MODULE,

		.min_keysize		= CAST5_MIN_KEY_SIZE,

		.max_keysize		= CAST5_MAX_KEY_SIZE,

		.ivsize			= CAST5_BLOCK_SIZE,

		.chunksize		= CAST5_BLOCK_SIZE,

		.setkey			= cast5_setkey_skcipher,

		.encrypt		= ctr_crypt,

		.decrypt		= ctr_crypt,

	}

};

crypto/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -1372,6 +1372,7 @@ config CRYPTO_CAST5_AVX_X86_64 
	select CRYPTO_CAST5

	select CRYPTO_CAST_COMMON

	select CRYPTO_SIMD

	imply CRYPTO_CTR

	help

	  The CAST5 encryption algorithm (synonymous with CAST-128) is

	  described in RFC2144.