1 files changed, 17 insertions, 108 deletions

diff --git a/crypto/arc4.c b/crypto/arc4.c
index a2120e06bf84..aa79571dbd49 100644
--- a/crypto/arc4.c
+++ b/crypto/arc4.c
@@ -13,84 +13,15 @@
 #include <linux/init.h>
 #include <linux/module.h>
 
-struct arc4_ctx {
-	u32 S[256];
-	u32 x, y;
-};
-
-static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
-			unsigned int key_len)
-{
-	struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
-	int i, j = 0, k = 0;
-
-	ctx->x = 1;
-	ctx->y = 0;
-
-	for (i = 0; i < 256; i++)
-		ctx->S[i] = i;
-
-	for (i = 0; i < 256; i++) {
-		u32 a = ctx->S[i];
-		j = (j + in_key[k] + a) & 0xff;
-		ctx->S[i] = ctx->S[j];
-		ctx->S[j] = a;
-		if (++k >= key_len)
-			k = 0;
-	}
-
-	return 0;
-}
-
-static int arc4_set_key_skcipher(struct crypto_skcipher *tfm, const u8 *in_key,
-				 unsigned int key_len)
+static int crypto_arc4_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			      unsigned int key_len)
 {
-	return arc4_set_key(&tfm->base, in_key, key_len);
-}
-
-static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in,
-		       unsigned int len)
-{
-	u32 *const S = ctx->S;
-	u32 x, y, a, b;
-	u32 ty, ta, tb;
-
-	if (len == 0)
-		return;
-
-	x = ctx->x;
-	y = ctx->y;
-
-	a = S[x];
-	y = (y + a) & 0xff;
-	b = S[y];
-
-	do {
-		S[y] = a;
-		a = (a + b) & 0xff;
-		S[x] = b;
-		x = (x + 1) & 0xff;
-		ta = S[x];
-		ty = (y + ta) & 0xff;
-		tb = S[ty];
-		*out++ = *in++ ^ S[a];
-		if (--len == 0)
-			break;
-		y = ty;
-		a = ta;
-		b = tb;
-	} while (true);
-
-	ctx->x = x;
-	ctx->y = y;
-}
+	struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-static void arc4_crypt_one(struct crypto_tfm *tfm, u8 *out, const u8 *in)
-{
-	arc4_crypt(crypto_tfm_ctx(tfm), out, in, 1);
+	return arc4_setkey(ctx, in_key, key_len);
 }
 
-static int ecb_arc4_crypt(struct skcipher_request *req)
+static int crypto_arc4_crypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct arc4_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -108,54 +39,32 @@ static int ecb_arc4_crypt(struct skcipher_request *req)
 	return err;
 }
 
-static struct crypto_alg arc4_cipher = {
-	.cra_name		=	"arc4",
-	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
-	.cra_blocksize		=	ARC4_BLOCK_SIZE,
-	.cra_ctxsize		=	sizeof(struct arc4_ctx),
-	.cra_module		=	THIS_MODULE,
-	.cra_u			=	{
-		.cipher = {
-			.cia_min_keysize	=	ARC4_MIN_KEY_SIZE,
-			.cia_max_keysize	=	ARC4_MAX_KEY_SIZE,
-			.cia_setkey		=	arc4_set_key,
-			.cia_encrypt		=	arc4_crypt_one,
-			.cia_decrypt		=	arc4_crypt_one,
-		},
-	},
-};
-
-static struct skcipher_alg arc4_skcipher = {
+static struct skcipher_alg arc4_alg = {
+	/*
+	 * For legacy reasons, this is named "ecb(arc4)", not "arc4".
+	 * Nevertheless it's actually a stream cipher, not a block cipher.
+	 */
 	.base.cra_name		=	"ecb(arc4)",
+	.base.cra_driver_name	=	"ecb(arc4)-generic",
 	.base.cra_priority	=	100,
 	.base.cra_blocksize	=	ARC4_BLOCK_SIZE,
 	.base.cra_ctxsize	=	sizeof(struct arc4_ctx),
 	.base.cra_module	=	THIS_MODULE,
 	.min_keysize		=	ARC4_MIN_KEY_SIZE,
 	.max_keysize		=	ARC4_MAX_KEY_SIZE,
-	.setkey			=	arc4_set_key_skcipher,
-	.encrypt		=	ecb_arc4_crypt,
-	.decrypt		=	ecb_arc4_crypt,
+	.setkey			=	crypto_arc4_setkey,
+	.encrypt		=	crypto_arc4_crypt,
+	.decrypt		=	crypto_arc4_crypt,
 };
 
 static int __init arc4_init(void)
 {
-	int err;
-
-	err = crypto_register_alg(&arc4_cipher);
-	if (err)
-		return err;
-
-	err = crypto_register_skcipher(&arc4_skcipher);
-	if (err)
-		crypto_unregister_alg(&arc4_cipher);
-	return err;
+	return crypto_register_skcipher(&arc4_alg);
 }
 
 static void __exit arc4_exit(void)
 {
-	crypto_unregister_alg(&arc4_cipher);
-	crypto_unregister_skcipher(&arc4_skcipher);
+	crypto_unregister_skcipher(&arc4_alg);
 }
 
 subsys_initcall(arc4_init);
@@ -164,4 +73,4 @@ module_exit(arc4_exit);
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
-MODULE_ALIAS_CRYPTO("arc4");
+MODULE_ALIAS_CRYPTO("ecb(arc4)");