1 files changed, 42 insertions, 129 deletions

diff --git a/crypto/arc4.c b/crypto/arc4.c
index f1a81925558f..1608018111d0 100644
--- a/crypto/arc4.c
+++ b/crypto/arc4.c
@@ -1,163 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Cryptographic API
  *
  * ARC4 Cipher Algorithm
  *
  * Jon Oberheide <jon@oberheide.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
  */
 
-#include <linux/module.h>
+#include <crypto/arc4.h>
+#include <crypto/internal/skcipher.h>
 #include <linux/init.h>
-#include <linux/crypto.h>
-#include <crypto/algapi.h>
-
-#define ARC4_MIN_KEY_SIZE	1
-#define ARC4_MAX_KEY_SIZE	256
-#define ARC4_BLOCK_SIZE		1
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
 
-struct arc4_ctx {
-	u32 S[256];
-	u32 x, y;
-};
+#define ARC4_ALIGN __alignof__(struct arc4_ctx)
 
-static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
-			unsigned int key_len)
+static int crypto_arc4_setkey(struct crypto_lskcipher *tfm, const u8 *in_key,
+			      unsigned int key_len)
 {
-	struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
-	int i, j = 0, k = 0;
+	struct arc4_ctx *ctx = crypto_lskcipher_ctx(tfm);
 
-	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;
+	return arc4_setkey(ctx, in_key, key_len);
 }
 
-static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in,
-		       unsigned int len)
+static int crypto_arc4_crypt(struct crypto_lskcipher *tfm, const u8 *src,
+			     u8 *dst, unsigned nbytes, u8 *siv, u32 flags)
 {
-	u32 *const S = ctx->S;
-	u32 x, y, a, b;
-	u32 ty, ta, tb;
-
-	if (len == 0)
-		return;
-
-	x = ctx->x;
-	y = ctx->y;
+	struct arc4_ctx *ctx = crypto_lskcipher_ctx(tfm);
 
-	a = S[x];
-	y = (y + a) & 0xff;
-	b = S[y];
+	if (!(flags & CRYPTO_LSKCIPHER_FLAG_CONT))
+		memcpy(siv, ctx, sizeof(*ctx));
 
-	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 = (struct arc4_ctx *)siv;
 
-	ctx->x = x;
-	ctx->y = y;
-}
-
-static void arc4_crypt_one(struct crypto_tfm *tfm, u8 *out, const u8 *in)
-{
-	arc4_crypt(crypto_tfm_ctx(tfm), out, in, 1);
+	arc4_crypt(ctx, dst, src, nbytes);
+	return 0;
 }
 
-static int ecb_arc4_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
-			  struct scatterlist *src, unsigned int nbytes)
+static int crypto_arc4_init(struct crypto_lskcipher *tfm)
 {
-	struct arc4_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
-	struct blkcipher_walk walk;
-	int err;
-
-	blkcipher_walk_init(&walk, dst, src, nbytes);
-
-	err = blkcipher_walk_virt(desc, &walk);
+	pr_warn_ratelimited("\"%s\" (%ld) uses obsolete ecb(arc4) skcipher\n",
+			    current->comm, (unsigned long)current->pid);
 
-	while (walk.nbytes > 0) {
-		u8 *wsrc = walk.src.virt.addr;
-		u8 *wdst = walk.dst.virt.addr;
-
-		arc4_crypt(ctx, wdst, wsrc, walk.nbytes);
-
-		err = blkcipher_walk_done(desc, &walk, 0);
-	}
-
-	return err;
+	return 0;
 }
 
-static struct crypto_alg arc4_algs[2] = { {
-	.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,
-		},
-	},
-}, {
-	.cra_name		=	"ecb(arc4)",
-	.cra_priority		=	100,
-	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
-	.cra_blocksize		=	ARC4_BLOCK_SIZE,
-	.cra_ctxsize		=	sizeof(struct arc4_ctx),
-	.cra_alignmask		=	0,
-	.cra_type		=	&crypto_blkcipher_type,
-	.cra_module		=	THIS_MODULE,
-	.cra_u			=	{
-		.blkcipher = {
-			.min_keysize	=	ARC4_MIN_KEY_SIZE,
-			.max_keysize	=	ARC4_MAX_KEY_SIZE,
-			.setkey		=	arc4_set_key,
-			.encrypt	=	ecb_arc4_crypt,
-			.decrypt	=	ecb_arc4_crypt,
-		},
-	},
-} };
+static struct lskcipher_alg arc4_alg = {
+	.co.base.cra_name		=	"arc4",
+	.co.base.cra_driver_name	=	"arc4-generic",
+	.co.base.cra_priority		=	100,
+	.co.base.cra_blocksize		=	ARC4_BLOCK_SIZE,
+	.co.base.cra_ctxsize		=	sizeof(struct arc4_ctx),
+	.co.base.cra_alignmask		=	ARC4_ALIGN - 1,
+	.co.base.cra_module		=	THIS_MODULE,
+	.co.min_keysize			=	ARC4_MIN_KEY_SIZE,
+	.co.max_keysize			=	ARC4_MAX_KEY_SIZE,
+	.co.statesize			=	sizeof(struct arc4_ctx),
+	.setkey				=	crypto_arc4_setkey,
+	.encrypt			=	crypto_arc4_crypt,
+	.decrypt			=	crypto_arc4_crypt,
+	.init				=	crypto_arc4_init,
+};
 
 static int __init arc4_init(void)
 {
-	return crypto_register_algs(arc4_algs, ARRAY_SIZE(arc4_algs));
+	return crypto_register_lskcipher(&arc4_alg);
 }
 
 static void __exit arc4_exit(void)
 {
-	crypto_unregister_algs(arc4_algs, ARRAY_SIZE(arc4_algs));
+	crypto_unregister_lskcipher(&arc4_alg);
 }
 
 module_init(arc4_init);
@@ -166,4 +79,4 @@ 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)");