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>

1 files changed, 25 insertions, 0 deletions

diff --git a/arch/x86/crypto/twofish_avx_glue.c b/arch/x86/crypto/twofish_avx_glue.c
index 3358e23f9ffb..3750b2cd3019 100644
--- a/arch/x86/crypto/twofish_avx_glue.c
+++ b/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,