crypto: x86/twofish-3way - remove XTS algorithm

The XTS template now wraps an ECB mode algorithm rather than the block
cipher directly.  Therefore it is now redundant for crypto modules to
wrap their ECB code with generic XTS code themselves via xts_crypt().

Remove the xts-twofish-3way algorithm which did this.  Users who request
xts(twofish) and previously would have gotten xts-twofish-3way will now
get xts(ecb-twofish-3way) instead, which is just as fast.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/x86/crypto/twofish_avx_glue.c

@@ -79,6 +79,31 @@ static void twofish_xts_dec(void *ctx, u128 *dst, const u128 *src, le128 *iv)
 				  GLUE_FUNC_CAST(twofish_dec_blk));
 }
 
+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;
+
+	err = xts_check_key(tfm, key, keylen);
+	if (err)
+		return err;
+
+	/* 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 const struct common_glue_ctx twofish_enc = {
 	.num_funcs = 3,

arch/x86/crypto/twofish_glue_3way.c

@@ -30,7 +30,6 @@
 #include <crypto/b128ops.h>
 #include <asm/crypto/twofish.h>
 #include <asm/crypto/glue_helper.h>
-#include <crypto/xts.h>
 
 EXPORT_SYMBOL_GPL(__twofish_enc_blk_3way);
 EXPORT_SYMBOL_GPL(twofish_dec_blk_3way);
@@ -182,94 +181,6 @@ static int ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
 	return glue_ctr_crypt_128bit(&twofish_ctr, desc, dst, src, nbytes);
 }
 
-static void encrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
-{
-	const unsigned int bsize = TF_BLOCK_SIZE;
-	struct twofish_ctx *ctx = priv;
-	int i;
-
-	if (nbytes == 3 * bsize) {
-		twofish_enc_blk_3way(ctx, srcdst, srcdst);
-		return;
-	}
-
-	for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
-		twofish_enc_blk(ctx, srcdst, srcdst);
-}
-
-static void decrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
-{
-	const unsigned int bsize = TF_BLOCK_SIZE;
-	struct twofish_ctx *ctx = priv;
-	int i;
-
-	if (nbytes == 3 * bsize) {
-		twofish_dec_blk_3way(ctx, srcdst, srcdst);
-		return;
-	}
-
-	for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
-		twofish_dec_blk(ctx, srcdst, srcdst);
-}
-
-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;
-
-	err = xts_check_key(tfm, key, keylen);
-	if (err)
-		return err;
-
-	/* 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);
-}
-EXPORT_SYMBOL_GPL(xts_twofish_setkey);
-
-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);
-	le128 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);
-	le128 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 tf_algs[] = { {
 	.cra_name		= "ecb(twofish)",
 	.cra_driver_name	= "ecb-twofish-3way",
@@ -329,26 +240,6 @@ static struct crypto_alg tf_algs[] = { {
 			.decrypt	= ctr_crypt,
 		},
 	},
-}, {
-	.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_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,
-		},
-	},
 } };
 
 static bool is_blacklisted_cpu(void)

arch/x86/include/asm/crypto/twofish.h

@@ -6,11 +6,6 @@
 #include <crypto/twofish.h>
 #include <crypto/b128ops.h>
 
-struct twofish_xts_ctx {
-	struct twofish_ctx tweak_ctx;
-	struct twofish_ctx crypt_ctx;
-};
-
 /* regular block cipher functions from twofish_x86_64 module */
 asmlinkage void twofish_enc_blk(struct twofish_ctx *ctx, u8 *dst,
 				const u8 *src);
@@ -30,7 +25,4 @@ extern void twofish_enc_blk_ctr(void *ctx, u128 *dst, const u128 *src,
 extern void twofish_enc_blk_ctr_3way(void *ctx, u128 *dst, const u128 *src,
 				     le128 *iv);
 
-extern int xts_twofish_setkey(struct crypto_tfm *tfm, const u8 *key,
-			      unsigned int keylen);
-
 #endif /* ASM_X86_TWOFISH_H */

crypto/Kconfig

@@ -1584,7 +1584,6 @@ config CRYPTO_TWOFISH_X86_64_3WAY
 	select CRYPTO_TWOFISH_COMMON
 	select CRYPTO_TWOFISH_X86_64
 	select CRYPTO_GLUE_HELPER_X86
-	select CRYPTO_XTS
 	help
 	  Twofish cipher algorithm (x86_64, 3-way parallel).