crypto/arc4: convert this stream cipher into a block cipher

Commit Message

Sebastian Andrzej Siewior Feb. 12, 2010, 8:42 a.m. UTC

None

Patch

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 81c185a..5fab1c3 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -561,7 +561,7 @@  config CRYPTO_ANUBIS
 
 config CRYPTO_ARC4
 	tristate "ARC4 cipher algorithm"
-	select CRYPTO_ALGAPI
+	select CRYPTO_BLKCIPHER
 	help
 	  ARC4 cipher algorithm.
 
diff --git a/crypto/arc4.c b/crypto/arc4.c
index 8be47e1..b67b656 100644
--- a/crypto/arc4.c
+++ b/crypto/arc4.c
@@ -1,4 +1,4 @@ 
-/* 
+/*
  * Cryptographic API
  *
  * ARC4 Cipher Algorithm
@@ -13,76 +13,124 @@ 
  */
 #include <linux/module.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
 
-struct arc4_ctx {
+struct arc4_iv {
 	u8 S[256];
 	u8 x, y;
 };
 
+struct arc4_ctx {
+	struct arc4_iv iv;
+	u8 new_key;
+};
+
 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;
+	ctx->iv.x = 1;
+	ctx->iv.y = 0;
 
-	for(i = 0; i < 256; i++)
-		ctx->S[i] = i;
+	for (i = 0; i < 256; i++)
+		ctx->iv.S[i] = i;
 
-	for(i = 0; i < 256; i++)
+	for (i = 0; i < 256; i++)
 	{
-		u8 a = ctx->S[i];
+		u8 a = ctx->iv.S[i];
 		j = (j + in_key[k] + a) & 0xff;
-		ctx->S[i] = ctx->S[j];
-		ctx->S[j] = a;
-		if(++k >= key_len)
+		ctx->iv.S[i] = ctx->iv.S[j];
+		ctx->iv.S[j] = a;
+		if (++k >= key_len)
 			k = 0;
 	}
-
+	ctx->new_key = 1;
 	return 0;
 }
 
-static void arc4_crypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
+static void arc4_ivsetup(struct arc4_ctx *ctx, u8 *iv)
 {
-	struct arc4_ctx *ctx = crypto_tfm_ctx(tfm);
+	if (unlikely(!ctx->new_key))
+		return;
+	memcpy(iv, &ctx->iv, sizeof(ctx->iv));
+	ctx->new_key = 0;
+}
 
-	u8 *const S = ctx->S;
-	u8 x = ctx->x;
-	u8 y = ctx->y;
+static int arc4_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		struct scatterlist *src, unsigned int nbytes)
+{
+	struct blkcipher_walk walk;
+	struct crypto_blkcipher *tfm = desc->tfm;
+	struct arc4_ctx *ctx = crypto_blkcipher_ctx(tfm);
+	struct arc4_iv *iv;
+	u8 *S;
+	u8 x;
+	u8 y;
 	u8 a, b;
+	int ret;
+
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	ret = blkcipher_walk_virt(desc, &walk);
+	if (ret)
+		return ret;
+
+	arc4_ivsetup(ctx, walk.iv);
+
+	iv = (struct arc4_iv *)walk.iv;
+
+	S = iv->S;
+	x = iv->x;
+	y = iv->y;
+
+	while (walk.nbytes) {
+		u8 *in = walk.src.virt.addr;
+		u8 *out = walk.dst.virt.addr;
+		u32 i;
+
+		for (i = 0; i < walk.nbytes; i++) {
+			a = S[x];
+			y = (y + a) & 0xff;
+			b = S[y];
+			S[x] = b;
+			S[y] = a;
+			x = (x + 1) & 0xff;
+			*out = *in ^ S[(a + b) & 0xff];
+
+			in++;
+			out++;
+		}
+		ret = blkcipher_walk_done(desc, &walk, 0);
+		WARN_ON(ret < 0);
+	}
 
-	a = S[x];
-	y = (y + a) & 0xff;
-	b = S[y];
-	S[x] = b;
-	S[y] = a;
-	x = (x + 1) & 0xff;
-	*out++ = *in ^ S[(a + b) & 0xff];
-
-	ctx->x = x;
-	ctx->y = y;
+	iv->x = x;
+	iv->y = y;
+	return ret;
 }
 
 static struct crypto_alg arc4_alg = {
-	.cra_name		=	"arc4",
-	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.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_type		=	&crypto_blkcipher_type,
+	.cra_alignmask		=	3,
 	.cra_module		=	THIS_MODULE,
 	.cra_list		=	LIST_HEAD_INIT(arc4_alg.cra_list),
-	.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,
-	.cia_decrypt	  	=	arc4_crypt } }
+	.cra_u			=	{ .blkcipher = {
+	.min_keysize		=	ARC4_MIN_KEY_SIZE,
+	.max_keysize		=	ARC4_MAX_KEY_SIZE,
+	.ivsize			=	sizeof(struct arc4_iv),
+	.setkey			=	arc4_set_key,
+	.encrypt		=	arc4_crypt,
+	.decrypt		=	arc4_crypt } }
 };
 
 static int __init arc4_init(void)
diff --git a/crypto/testmgr.h b/crypto/testmgr.h
index fb76517..423cf86 100644
--- a/crypto/testmgr.h
+++ b/crypto/testmgr.h
@@ -24,7 +24,8 @@ 
 #define MAX_TAP			8
 
 #define MAX_KEYLEN		56
-#define MAX_IVLEN		32
+/* sizeof arc4_iv */
+#define MAX_IVLEN		260
 
 struct hash_testvec {
 	/* only used with keyed hash algorithms */
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index dd9a09c..ddce826 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -3076,7 +3076,6 @@  config PPP_MPPE
        select CRYPTO
        select CRYPTO_SHA1
        select CRYPTO_ARC4
-       select CRYPTO_ECB
        ---help---
          Support for the MPPE Encryption protocol, as employed by the
 	 Microsoft Point-to-Point Tunneling Protocol.
diff --git a/drivers/net/wireless/hostap/Kconfig b/drivers/net/wireless/hostap/Kconfig
index 287d827..2548b56 100644
--- a/drivers/net/wireless/hostap/Kconfig
+++ b/drivers/net/wireless/hostap/Kconfig
@@ -5,10 +5,8 @@  config HOSTAP
 	select WEXT_PRIV
 	select CRYPTO
 	select CRYPTO_ARC4
-	select CRYPTO_ECB
 	select CRYPTO_AES
 	select CRYPTO_MICHAEL_MIC
-	select CRYPTO_ECB
 	select CRC32
 	select LIB80211
 	select LIB80211_CRYPT_WEP
diff --git a/drivers/net/wireless/ipw2x00/Kconfig b/drivers/net/wireless/ipw2x00/Kconfig
index 2715b10..2f2b7d9 100644
--- a/drivers/net/wireless/ipw2x00/Kconfig
+++ b/drivers/net/wireless/ipw2x00/Kconfig
@@ -159,10 +159,8 @@  config LIBIPW
 	select WEXT_SPY
 	select CRYPTO
 	select CRYPTO_ARC4
-	select CRYPTO_ECB
 	select CRYPTO_AES
 	select CRYPTO_MICHAEL_MIC
-	select CRYPTO_ECB
 	select CRC32
 	select LIB80211
 	select LIB80211_CRYPT_WEP
diff --git a/net/mac80211/Kconfig b/net/mac80211/Kconfig
index a10d508..7925f44 100644
--- a/net/mac80211/Kconfig
+++ b/net/mac80211/Kconfig
@@ -2,7 +2,6 @@  config MAC80211
 	tristate "Generic IEEE 802.11 Networking Stack (mac80211)"
 	depends on CFG80211
 	select CRYPTO
-	select CRYPTO_ECB
 	select CRYPTO_ARC4
 	select CRYPTO_AES
 	select CRC32