crypto: twofish-x86_64-3way - add xts support

Patch adds XTS support for twofish-x86_64-3way by using xts_crypt(). Patch has
been tested with tcrypt and automated filesystem tests.

Tcrypt benchmarks results (twofish-3way/twofish-asm speed ratios):

Intel Celeron T1600 (fam:6, model:15, step:13):

size    xts-enc xts-dec
16B     0.98x   1.00x
64B     1.14x   1.15x
256B    1.23x   1.25x
1024B   1.26x   1.29x
8192B   1.28x   1.30x

AMD Phenom II 1055T (fam:16, model:10):

size    xts-enc xts-dec
16B     1.03x   1.03x
64B     1.13x   1.16x
256B    1.20x   1.20x
1024B   1.22x   1.22x
8192B   1.22x   1.21x

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 117 insertions, 2 deletions

diff --git a/arch/x86/crypto/twofish_glue_3way.c b/arch/x86/crypto/twofish_glue_3way.c
index fa9151df3637..954f59eeb7b4 100644
--- a/arch/x86/crypto/twofish_glue_3way.c
+++ b/arch/x86/crypto/twofish_glue_3way.c
@@ -33,11 +33,16 @@
 #include <crypto/twofish.h>
 #include <crypto/b128ops.h>
 #include <crypto/lrw.h>
+#include <crypto/xts.h>
 
 #if defined(CONFIG_CRYPTO_LRW) || defined(CONFIG_CRYPTO_LRW_MODULE)
 #define HAS_LRW
 #endif
 
+#if defined(CONFIG_CRYPTO_XTS) || defined(CONFIG_CRYPTO_XTS_MODULE)
+#define HAS_XTS
+#endif
+
 /* regular block cipher functions from twofish_x86_64 module */
 asmlinkage void twofish_enc_blk(struct twofish_ctx *ctx, u8 *dst,
                                 const u8 *src);
@@ -437,7 +442,7 @@ static struct crypto_alg blk_ctr_alg = {
         },
 };
 
-#ifdef HAS_LRW
+#if defined(HAS_LRW) || defined(HAS_XTS)
 
 static void encrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
 {
@@ -469,6 +474,10 @@ static void decrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
                 twofish_dec_blk(ctx, srcdst, srcdst);
 }
 
+#endif
+
+#ifdef HAS_LRW
+
 struct twofish_lrw_ctx {
         struct lrw_table_ctx lrw_table;
         struct twofish_ctx twofish_ctx;
@@ -555,6 +564,99 @@ static struct crypto_alg blk_lrw_alg = {
 
 #endif
 
+#ifdef HAS_XTS
+
+struct twofish_xts_ctx {
+        struct twofish_ctx tweak_ctx;
+        struct twofish_ctx crypt_ctx;
+};
+
+static int xts_twofish_setkey(struct crypto_tfm *tfm, const u8 *key,
+                              unsigned int keylen)
+{
+        struct twofish_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 = __twofish_setkey(&ctx->crypt_ctx, key, keylen / 2, flags);
+        if (err)
+                return err;
+
+        /* second half of xts-key is for tweak */
+        return __twofish_setkey(&ctx->tweak_ctx, key + keylen / 2, keylen / 2,
+                                flags);
+}
+
+static int xts_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+                       struct scatterlist *src, unsigned int nbytes)
+{
+        struct twofish_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+        be128 buf[3];
+        struct xts_crypt_req req = {
+                .tbuf = buf,
+                .tbuflen = sizeof(buf),
+
+                .tweak_ctx = &ctx->tweak_ctx,
+                .tweak_fn = XTS_TWEAK_CAST(twofish_enc_blk),
+                .crypt_ctx = &ctx->crypt_ctx,
+                .crypt_fn = encrypt_callback,
+        };
+
+        return xts_crypt(desc, dst, src, nbytes, &req);
+}
+
+static int xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+                       struct scatterlist *src, unsigned int nbytes)
+{
+        struct twofish_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+        be128 buf[3];
+        struct xts_crypt_req req = {
+                .tbuf = buf,
+                .tbuflen = sizeof(buf),
+
+                .tweak_ctx = &ctx->tweak_ctx,
+                .tweak_fn = XTS_TWEAK_CAST(twofish_enc_blk),
+                .crypt_ctx = &ctx->crypt_ctx,
+                .crypt_fn = decrypt_callback,
+        };
+
+        return xts_crypt(desc, dst, src, nbytes, &req);
+}
+
+static struct crypto_alg blk_xts_alg = {
+        .cra_name               = "xts(twofish)",
+        .cra_driver_name        = "xts-twofish-3way",
+        .cra_priority           = 300,
+        .cra_flags              = CRYPTO_ALG_TYPE_BLKCIPHER,
+        .cra_blocksize          = TF_BLOCK_SIZE,
+        .cra_ctxsize            = sizeof(struct twofish_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    = TF_MIN_KEY_SIZE * 2,
+                        .max_keysize    = TF_MAX_KEY_SIZE * 2,
+                        .ivsize         = TF_BLOCK_SIZE,
+                        .setkey         = xts_twofish_setkey,
+                        .encrypt        = xts_encrypt,
+                        .decrypt        = xts_decrypt,
+                },
+        },
+};
+
+#endif
+
 int __init init(void)
 {
         int err;
@@ -573,13 +675,23 @@ int __init init(void)
         if (err)
                 goto blk_lrw_err;
 #endif
+#ifdef HAS_XTS
+        err = crypto_register_alg(&blk_xts_alg);
+        if (err)
+                goto blk_xts_err;
+#endif
 
         return 0;
 
+#ifdef HAS_XTS
+        crypto_unregister_alg(&blk_xts_alg);
+blk_xts_err:
+#endif
 #ifdef HAS_LRW
+        crypto_unregister_alg(&blk_lrw_alg);
 blk_lrw_err:
-        crypto_unregister_alg(&blk_ctr_alg);
 #endif
+        crypto_unregister_alg(&blk_ctr_alg);
 ctr_err:
         crypto_unregister_alg(&blk_cbc_alg);
 cbc_err:
@@ -590,6 +702,9 @@ ecb_err:
 
 void __exit fini(void)
 {
+#ifdef HAS_XTS
+        crypto_unregister_alg(&blk_xts_alg);
+#endif
 #ifdef HAS_LRW
         crypto_unregister_alg(&blk_lrw_alg);
 #endif