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crypto: x86/cast5 - drop CTR mode implementation

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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: Eric Biggers <ebiggers@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel 2021-01-05 17:47:56 +01:00 committed by Herbert Xu
parent 2e9440ae6e
commit e2d60e2f59
2 changed files with 1 additions and 103 deletions
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103
arch/x86/crypto/cast5_avx_glue.c
View File

@ -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,
}
};

1
crypto/Kconfig
View File

@ -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.