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crypto: serpent-sse2 - add xts support
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Patch adds XTS support for serpent-sse2 by using xts_crypt(). Patch has been
tested with tcrypt and automated filesystem tests.

Tcrypt benchmarks results (serpent-sse2/serpent_generic speed ratios):

Intel Celeron T1600 (x86_64) (fam:6, model:15, step:13):
size    xts-enc xts-dec
16B     0.98x   1.00x
64B     1.00x   1.01x
256B    2.78x   2.75x
1024B   3.30x   3.26x
8192B   3.39x   3.30x

AMD Phenom II 1055T (x86_64) (fam:16, model:10):
size    xts-enc xts-dec
16B     1.05x   1.02x
64B     1.04x   1.03x
256B    2.10x   2.05x
1024B   2.34x   2.35x
8192B   2.34x   2.40x

Intel Atom N270 (i586):
size    xts-enc xts-dec
16B     0.95x   0.96x
64B     1.53x   1.50x
256B    1.72x   1.75x
1024B   1.88x   1.87x
8192B   1.86x   1.83x

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Jussi Kivilinna authored and Herbert Xu committed Nov 21, 2011
1 parent 1848205 commit 5962f8b
Showing 1 changed file with 178 additions and 2 deletions.
180 changes: 178 additions & 2 deletions arch/x86/crypto/serpent_sse2_glue.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@
#include <crypto/b128ops.h>
#include <crypto/ctr.h>
#include <crypto/lrw.h>
#include <crypto/xts.h>
#include <asm/i387.h>
#include <asm/serpent.h>
#include <crypto/scatterwalk.h>
Expand All @@ -50,6 +51,10 @@
#define HAS_LRW
#endif

#if defined(CONFIG_CRYPTO_XTS) || defined(CONFIG_CRYPTO_XTS_MODULE)
#define HAS_XTS
#endif

struct async_serpent_ctx {
struct cryptd_ablkcipher *cryptd_tfm;
};
Expand Down Expand Up @@ -465,7 +470,7 @@ static struct crypto_alg blk_ctr_alg = {
},
};

#ifdef HAS_LRW
#if defined(HAS_LRW) || defined(HAS_XTS)

struct crypt_priv {
struct serpent_ctx *ctx;
Expand Down Expand Up @@ -506,6 +511,10 @@ static void decrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
__serpent_decrypt(ctx->ctx, srcdst, srcdst);
}

#endif

#ifdef HAS_LRW

struct serpent_lrw_ctx {
struct lrw_table_ctx lrw_table;
struct serpent_ctx serpent_ctx;
Expand Down Expand Up @@ -611,6 +620,114 @@ static struct crypto_alg blk_lrw_alg = {

#endif

#ifdef HAS_XTS

struct serpent_xts_ctx {
struct serpent_ctx tweak_ctx;
struct serpent_ctx crypt_ctx;
};

static int xts_serpent_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
struct serpent_xts_ctx *ctx = crypto_tfm_ctx(tfm);
u32 *flags = &tfm->crt_flags;
int err;

/* key consists of keys of equal size concatenated, therefore
* the length must be even
*/
if (keylen % 2) {
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
return -EINVAL;
}

/* first half of xts-key is for crypt */
err = __serpent_setkey(&ctx->crypt_ctx, key, keylen / 2);
if (err)
return err;

/* second half of xts-key is for tweak */
return __serpent_setkey(&ctx->tweak_ctx, key + keylen / 2, keylen / 2);
}

static int xts_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes)
{
struct serpent_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
be128 buf[SERPENT_PARALLEL_BLOCKS];
struct crypt_priv crypt_ctx = {
.ctx = &ctx->crypt_ctx,
.fpu_enabled = false,
};
struct xts_crypt_req req = {
.tbuf = buf,
.tbuflen = sizeof(buf),

.tweak_ctx = &ctx->tweak_ctx,
.tweak_fn = XTS_TWEAK_CAST(__serpent_encrypt),
.crypt_ctx = &crypt_ctx,
.crypt_fn = encrypt_callback,
};
int ret;

ret = xts_crypt(desc, dst, src, nbytes, &req);
serpent_fpu_end(crypt_ctx.fpu_enabled);

return ret;
}

static int xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
struct scatterlist *src, unsigned int nbytes)
{
struct serpent_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
be128 buf[SERPENT_PARALLEL_BLOCKS];
struct crypt_priv crypt_ctx = {
.ctx = &ctx->crypt_ctx,
.fpu_enabled = false,
};
struct xts_crypt_req req = {
.tbuf = buf,
.tbuflen = sizeof(buf),

.tweak_ctx = &ctx->tweak_ctx,
.tweak_fn = XTS_TWEAK_CAST(__serpent_encrypt),
.crypt_ctx = &crypt_ctx,
.crypt_fn = decrypt_callback,
};
int ret;

ret = xts_crypt(desc, dst, src, nbytes, &req);
serpent_fpu_end(crypt_ctx.fpu_enabled);

return ret;
}

static struct crypto_alg blk_xts_alg = {
.cra_name = "__xts-serpent-sse2",
.cra_driver_name = "__driver-xts-serpent-sse2",
.cra_priority = 0,
.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
.cra_blocksize = SERPENT_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct serpent_xts_ctx),
.cra_alignmask = 0,
.cra_type = &crypto_blkcipher_type,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(blk_xts_alg.cra_list),
.cra_u = {
.blkcipher = {
.min_keysize = SERPENT_MIN_KEY_SIZE * 2,
.max_keysize = SERPENT_MAX_KEY_SIZE * 2,
.ivsize = SERPENT_BLOCK_SIZE,
.setkey = xts_serpent_setkey,
.encrypt = xts_encrypt,
.decrypt = xts_decrypt,
},
},
};

#endif

static int ablk_set_key(struct crypto_ablkcipher *tfm, const u8 *key,
unsigned int key_len)
{
Expand Down Expand Up @@ -851,6 +968,46 @@ static struct crypto_alg ablk_lrw_alg = {

#endif

#ifdef HAS_XTS

static int ablk_xts_init(struct crypto_tfm *tfm)
{
struct cryptd_ablkcipher *cryptd_tfm;

cryptd_tfm = cryptd_alloc_ablkcipher("__driver-xts-serpent-sse2", 0, 0);
if (IS_ERR(cryptd_tfm))
return PTR_ERR(cryptd_tfm);
ablk_init_common(tfm, cryptd_tfm);
return 0;
}

static struct crypto_alg ablk_xts_alg = {
.cra_name = "xts(serpent)",
.cra_driver_name = "xts-serpent-sse2",
.cra_priority = 400,
.cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
.cra_blocksize = SERPENT_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct async_serpent_ctx),
.cra_alignmask = 0,
.cra_type = &crypto_ablkcipher_type,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(ablk_xts_alg.cra_list),
.cra_init = ablk_xts_init,
.cra_exit = ablk_exit,
.cra_u = {
.ablkcipher = {
.min_keysize = SERPENT_MIN_KEY_SIZE * 2,
.max_keysize = SERPENT_MAX_KEY_SIZE * 2,
.ivsize = SERPENT_BLOCK_SIZE,
.setkey = ablk_set_key,
.encrypt = ablk_encrypt,
.decrypt = ablk_decrypt,
},
},
};

#endif

static int __init serpent_sse2_init(void)
{
int err;
Expand Down Expand Up @@ -885,15 +1042,30 @@ static int __init serpent_sse2_init(void)
err = crypto_register_alg(&ablk_lrw_alg);
if (err)
goto ablk_lrw_err;
#endif
#ifdef HAS_XTS
err = crypto_register_alg(&blk_xts_alg);
if (err)
goto blk_xts_err;
err = crypto_register_alg(&ablk_xts_alg);
if (err)
goto ablk_xts_err;
#endif
return err;

#ifdef HAS_XTS
crypto_unregister_alg(&ablk_xts_alg);
ablk_xts_err:
crypto_unregister_alg(&blk_xts_alg);
blk_xts_err:
#endif
#ifdef HAS_LRW
crypto_unregister_alg(&ablk_lrw_alg);
ablk_lrw_err:
crypto_unregister_alg(&blk_lrw_alg);
blk_lrw_err:
crypto_unregister_alg(&ablk_ctr_alg);
#endif
crypto_unregister_alg(&ablk_ctr_alg);
ablk_ctr_err:
crypto_unregister_alg(&ablk_cbc_alg);
ablk_cbc_err:
Expand All @@ -910,6 +1082,10 @@ static int __init serpent_sse2_init(void)

static void __exit serpent_sse2_exit(void)
{
#ifdef HAS_XTS
crypto_unregister_alg(&ablk_xts_alg);
crypto_unregister_alg(&blk_xts_alg);
#endif
#ifdef HAS_LRW
crypto_unregister_alg(&ablk_lrw_alg);
crypto_unregister_alg(&blk_lrw_alg);
Expand Down

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