[PATCH 1/7] crypto: rename arc4

[PATCH 1/7] crypto: rename arc4

[Sebastian Andrzej Siewior]

The blk version of arc4 is comming. The rename ensures that the request
for arc4 loads both modules: this one and the new blk edition.

Cc: <linux-ppp@vger.kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
---
 crypto/Makefile              |    2 +-
 crypto/{arc4.c => arc4cip.c} |    1 +
 2 files changed, 2 insertions(+), 1 deletions(-)
 rename crypto/{arc4.c => arc4cip.c} (98%)

diff --git a/crypto/Makefile b/crypto/Makefile
index 9e8f619..1f15112 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -67,7 +67,7 @@ obj-$(CONFIG_CRYPTO_AES) += aes_generic.o
 obj-$(CONFIG_CRYPTO_CAMELLIA) += camellia.o
 obj-$(CONFIG_CRYPTO_CAST5) += cast5.o
 obj-$(CONFIG_CRYPTO_CAST6) += cast6.o
-obj-$(CONFIG_CRYPTO_ARC4) += arc4.o
+obj-$(CONFIG_CRYPTO_ARC4) += arc4cip.o
 obj-$(CONFIG_CRYPTO_TEA) += tea.o
 obj-$(CONFIG_CRYPTO_KHAZAD) += khazad.o
 obj-$(CONFIG_CRYPTO_ANUBIS) += anubis.o
diff --git a/crypto/arc4.c b/crypto/arc4cip.c
similarity index 98%
rename from crypto/arc4.c
rename to crypto/arc4cip.c
index 8be47e1..bf04659 100644
--- a/crypto/arc4.c
+++ b/crypto/arc4cip.c
@@ -102,3 +102,4 @@ module_exit(arc4_exit);
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
 MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
+MODULE_ALIAS("arc4");
-- 
1.6.6

[PATCH 2/7] crypto: add blkcipher implementation of ARC4

[Sebastian Andrzej Siewior]

This is a pure blkcipher implementation of ARC4. The internal state is
saved within an IV which is supplied by the user. The goal is that the
cipher does not change its internal state now, only the iv changes during
encryption.

Cc: <linux-ppp@vger.kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
---
 crypto/Kconfig   |   13 +++++
 crypto/Makefile  |    1 +
 crypto/arc4blk.c |  150 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 crypto/testmgr.h |    3 +-
 4 files changed, 166 insertions(+), 1 deletions(-)
 create mode 100644 crypto/arc4blk.c

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 81c185a..be9add2 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -570,6 +570,19 @@ config CRYPTO_ARC4
 	  WEP, but it should not be for other purposes because of the
 	  weakness of the algorithm.
 
+config CRYPTO_ARC4BLK
+	tristate "ARC4 cipher algorithm (alternative implemenation)"
+	select CRYPTO_BLKCIPHER
+	help
+	  ARC4 cipher algorithm. This is an alternative ARC4 implementation which
+	  will replace the other ARC4 implementation once all in-kernel users are
+	  converted.
+
+	  ARC4 is a stream cipher using keys ranging from 8 bits to 2048
+	  bits in length.  This algorithm is required for driver-based
+	  WEP, but it should not be for other purposes because of the
+	  weakness of the algorithm.
+
 config CRYPTO_BLOWFISH
 	tristate "Blowfish cipher algorithm"
 	select CRYPTO_ALGAPI
diff --git a/crypto/Makefile b/crypto/Makefile
index 1f15112..11300e3 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_CRYPTO_CAMELLIA) += camellia.o
 obj-$(CONFIG_CRYPTO_CAST5) += cast5.o
 obj-$(CONFIG_CRYPTO_CAST6) += cast6.o
 obj-$(CONFIG_CRYPTO_ARC4) += arc4cip.o
+obj-$(CONFIG_CRYPTO_ARC4BLK) += arc4blk.o
 obj-$(CONFIG_CRYPTO_TEA) += tea.o
 obj-$(CONFIG_CRYPTO_KHAZAD) += khazad.o
 obj-$(CONFIG_CRYPTO_ANUBIS) += anubis.o
diff --git a/crypto/arc4blk.c b/crypto/arc4blk.c
new file mode 100644
index 0000000..bdf938a
--- /dev/null
+++ b/crypto/arc4blk.c
@@ -0,0 +1,150 @@
+/*
+ * 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 <linux/init.h>
+#include <crypto/algapi.h>
+#include <crypto/arc4.h>
+
+#define ARC4_MIN_KEY_SIZE	1
+#define ARC4_MAX_KEY_SIZE	256
+#define ARC4_BLOCK_SIZE		1
+
+static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
+			unsigned int key_len)
+{
+	/*
+	 * ARC4 is special: The user should supply an IV as struct arc4_iv and
+	 * fill either the key or the iv.
+	 */
+	return 0;
+}
+
+static void arc4_key_to_iv(const u8 *in_key, u32 key_len, struct arc4_iv *iv)
+{
+	int i, j = 0, k = 0;
+
+	iv->iv.x = 1;
+	iv->iv.y = 0;
+
+	for (i = 0; i < 256; i++)
+		iv->iv.S[i] = i;
+
+	for (i = 0; i < 256; i++)
+	{
+		u8 a = iv->iv.S[i];
+		j = (j + in_key[k] + a) & 0xff;
+		iv->iv.S[i] = iv->iv.S[j];
+		iv->iv.S[j] = a;
+		if (++k >= key_len)
+			k = 0;
+	}
+}
+
+static void arc4_ivsetup(struct arc4_iv *iv)
+{
+	struct arc4_iv tmp_iv;
+
+	if (iv->type = ARC4_TYPE_IV)
+		return;
+
+	memcpy(&tmp_iv, iv, sizeof(tmp_iv));
+	arc4_key_to_iv(tmp_iv.key.key, tmp_iv.key.key_len, iv);
+	iv->type = ARC4_TYPE_IV;
+}
+
+static int arc4_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		struct scatterlist *src, unsigned int nbytes)
+{
+	struct blkcipher_walk walk;
+	struct arc4_iv *aiv;
+	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;
+
+	aiv = (struct arc4_iv *)walk.iv;
+	arc4_ivsetup(aiv);
+
+	S = aiv->iv.S;
+	x = aiv->iv.x;
+	y = aiv->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);
+	}
+
+	aiv->iv.x = x;
+	aiv->iv.y = y;
+	return ret;
+}
+
+static struct crypto_alg arc4_alg = {
+	.cra_name		=	"arc4",
+	.cra_priority		=	100,
+	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		=	ARC4_BLOCK_SIZE,
+	.cra_ctxsize		=	0,
+	.cra_type		=	&crypto_blkcipher_type,
+	.cra_alignmask		=	3,
+	.cra_module		=	THIS_MODULE,
+	.cra_list		=	LIST_HEAD_INIT(arc4_alg.cra_list),
+	.cra_u			=	{ .blkcipher = {
+	.min_keysize		=	0,
+	.max_keysize		=	0,
+	.ivsize			=	sizeof(struct arc4_iv),
+	.setkey			=	arc4_set_key,
+	.encrypt		=	arc4_crypt,
+	.decrypt		=	arc4_crypt } }
+};
+
+static int __init arc4_init(void)
+{
+	return crypto_register_alg(&arc4_alg);
+}
+
+static void __exit arc4_exit(void)
+{
+	crypto_unregister_alg(&arc4_alg);
+}
+
+module_init(arc4_init);
+module_exit(arc4_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
+MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
+MODULE_ALIAS("arc4");
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 */
-- 
1.6.6

[PATCH 7/7] net/ppp_mppe: convert from arc4 to arc4blk

[Sebastian Andrzej Siewior]

ecb(arc4) is getting replaced by arc4 which is a blkcipher by itself

Cc: <linux-ppp@vger.kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
---
 drivers/net/Kconfig    |    3 +--
 drivers/net/ppp_mppe.c |   12 ++++++------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index dd9a09c..4b5dd86 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -3075,8 +3075,7 @@ config PPP_MPPE
        depends on PPP && EXPERIMENTAL
        select CRYPTO
        select CRYPTO_SHA1
-       select CRYPTO_ARC4
-       select CRYPTO_ECB
+       select CRYPTO_ARC4BLK
        ---help---
          Support for the MPPE Encryption protocol, as employed by the
 	 Microsoft Point-to-Point Tunneling Protocol.
diff --git a/drivers/net/ppp_mppe.c b/drivers/net/ppp_mppe.c
index 6d1a1b8..4deaf70 100644
--- a/drivers/net/ppp_mppe.c
+++ b/drivers/net/ppp_mppe.c
@@ -42,7 +42,6 @@
  *                    MOD_DEC_USAGE_COUNT/MOD_INC_USAGE_COUNT which are
  *                    deprecated in 2.6
  */
-
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -55,6 +54,7 @@
 #include <linux/ppp_defs.h>
 #include <linux/ppp-comp.h>
 #include <linux/scatterlist.h>
+#include <crypto/arc4.h>
 
 #include "ppp_mppe.h"
 
@@ -162,11 +162,11 @@ static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
 {
 	struct scatterlist sg_in[1], sg_out[1];
 	struct blkcipher_desc desc = { .tfm = state->arc4 };
+	struct arc4_iv *iv = crypto_blkcipher_crt(state->arc4)->iv;
 
 	get_new_key_from_sha(state);
 	if (!initial_key) {
-		crypto_blkcipher_setkey(state->arc4, state->sha1_digest,
-					state->keylen);
+		arc4_setup_iv(iv, state->sha1_digest, state->keylen);
 		sg_init_table(sg_in, 1);
 		sg_init_table(sg_out, 1);
 		setup_sg(sg_in, state->sha1_digest, state->keylen);
@@ -184,7 +184,7 @@ static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
 		state->session_key[1] = 0x26;
 		state->session_key[2] = 0x9e;
 	}
-	crypto_blkcipher_setkey(state->arc4, state->session_key, state->keylen);
+	arc4_setup_iv(iv, state->session_key, state->keylen);
 }
 
 /*
@@ -204,7 +204,7 @@ static void *mppe_alloc(unsigned char *options, int optlen)
 		goto out;
 
 
-	state->arc4 = crypto_alloc_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC);
+	state->arc4 = crypto_alloc_blkcipher("arc4", 0, CRYPTO_ALG_ASYNC);
 	if (IS_ERR(state->arc4)) {
 		state->arc4 = NULL;
 		goto out_free;
@@ -712,7 +712,7 @@ static struct compressor ppp_mppe = {
 static int __init ppp_mppe_init(void)
 {
 	int answer;
-	if (!(crypto_has_blkcipher("ecb(arc4)", 0, CRYPTO_ALG_ASYNC) &&
+	if (!(crypto_has_blkcipher("arc4", 0, CRYPTO_ALG_ASYNC) &&
 	      crypto_has_hash("sha1", 0, CRYPTO_ALG_ASYNC)))
 		return -ENODEV;
 
-- 
1.6.6

Re: [PATCH 2/7] crypto: add blkcipher implementation of ARC4

[Herbert Xu]

On Sat, Apr 03, 2010 at 09:49:24AM +0200, Sebastian Andrzej Siewior wrote:
>
> +#include <crypto/arc4.h>

This file doesn't seem to exist in the kernel tree or your patch-set?

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
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[PATCH v2] crypto: add blkcipher implementation of ARC4

[Sebastian Andrzej Siewior]

This is a pure blkcipher implementation of ARC4. The internal state is
saved within an IV which is supplied by the user. The goal is that the
cipher does not change its internal state now, only the iv changes during
encryption.

Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
---
 crypto/Kconfig        |   13 ++++
 crypto/Makefile       |    1 +
 crypto/arc4blk.c      |  150 +++++++++++++++++++++++++++++++++++++++++++++++++
 crypto/testmgr.h      |    3 +-
 include/crypto/arc4.h |   26 +++++++++
 5 files changed, 192 insertions(+), 1 deletions(-)
 create mode 100644 crypto/arc4blk.c
 create mode 100644 include/crypto/arc4.h

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 81c185a..be9add2 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -570,6 +570,19 @@ config CRYPTO_ARC4
 	  WEP, but it should not be for other purposes because of the
 	  weakness of the algorithm.
 
+config CRYPTO_ARC4BLK
+	tristate "ARC4 cipher algorithm (alternative implemenation)"
+	select CRYPTO_BLKCIPHER
+	help
+	  ARC4 cipher algorithm. This is an alternative ARC4 implementation which
+	  will replace the other ARC4 implementation once all in-kernel users are
+	  converted.
+
+	  ARC4 is a stream cipher using keys ranging from 8 bits to 2048
+	  bits in length.  This algorithm is required for driver-based
+	  WEP, but it should not be for other purposes because of the
+	  weakness of the algorithm.
+
 config CRYPTO_BLOWFISH
 	tristate "Blowfish cipher algorithm"
 	select CRYPTO_ALGAPI
diff --git a/crypto/Makefile b/crypto/Makefile
index 1f15112..11300e3 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_CRYPTO_CAMELLIA) += camellia.o
 obj-$(CONFIG_CRYPTO_CAST5) += cast5.o
 obj-$(CONFIG_CRYPTO_CAST6) += cast6.o
 obj-$(CONFIG_CRYPTO_ARC4) += arc4cip.o
+obj-$(CONFIG_CRYPTO_ARC4BLK) += arc4blk.o
 obj-$(CONFIG_CRYPTO_TEA) += tea.o
 obj-$(CONFIG_CRYPTO_KHAZAD) += khazad.o
 obj-$(CONFIG_CRYPTO_ANUBIS) += anubis.o
diff --git a/crypto/arc4blk.c b/crypto/arc4blk.c
new file mode 100644
index 0000000..bdf938a
--- /dev/null
+++ b/crypto/arc4blk.c
@@ -0,0 +1,150 @@
+/*
+ * 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 <linux/init.h>
+#include <crypto/algapi.h>
+#include <crypto/arc4.h>
+
+#define ARC4_MIN_KEY_SIZE	1
+#define ARC4_MAX_KEY_SIZE	256
+#define ARC4_BLOCK_SIZE		1
+
+static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
+			unsigned int key_len)
+{
+	/*
+	 * ARC4 is special: The user should supply an IV as struct arc4_iv and
+	 * fill either the key or the iv.
+	 */
+	return 0;
+}
+
+static void arc4_key_to_iv(const u8 *in_key, u32 key_len, struct arc4_iv *iv)
+{
+	int i, j = 0, k = 0;
+
+	iv->iv.x = 1;
+	iv->iv.y = 0;
+
+	for (i = 0; i < 256; i++)
+		iv->iv.S[i] = i;
+
+	for (i = 0; i < 256; i++)
+	{
+		u8 a = iv->iv.S[i];
+		j = (j + in_key[k] + a) & 0xff;
+		iv->iv.S[i] = iv->iv.S[j];
+		iv->iv.S[j] = a;
+		if (++k >= key_len)
+			k = 0;
+	}
+}
+
+static void arc4_ivsetup(struct arc4_iv *iv)
+{
+	struct arc4_iv tmp_iv;
+
+	if (iv->type = ARC4_TYPE_IV)
+		return;
+
+	memcpy(&tmp_iv, iv, sizeof(tmp_iv));
+	arc4_key_to_iv(tmp_iv.key.key, tmp_iv.key.key_len, iv);
+	iv->type = ARC4_TYPE_IV;
+}
+
+static int arc4_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
+		struct scatterlist *src, unsigned int nbytes)
+{
+	struct blkcipher_walk walk;
+	struct arc4_iv *aiv;
+	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;
+
+	aiv = (struct arc4_iv *)walk.iv;
+	arc4_ivsetup(aiv);
+
+	S = aiv->iv.S;
+	x = aiv->iv.x;
+	y = aiv->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);
+	}
+
+	aiv->iv.x = x;
+	aiv->iv.y = y;
+	return ret;
+}
+
+static struct crypto_alg arc4_alg = {
+	.cra_name		=	"arc4",
+	.cra_priority		=	100,
+	.cra_flags		=	CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		=	ARC4_BLOCK_SIZE,
+	.cra_ctxsize		=	0,
+	.cra_type		=	&crypto_blkcipher_type,
+	.cra_alignmask		=	3,
+	.cra_module		=	THIS_MODULE,
+	.cra_list		=	LIST_HEAD_INIT(arc4_alg.cra_list),
+	.cra_u			=	{ .blkcipher = {
+	.min_keysize		=	0,
+	.max_keysize		=	0,
+	.ivsize			=	sizeof(struct arc4_iv),
+	.setkey			=	arc4_set_key,
+	.encrypt		=	arc4_crypt,
+	.decrypt		=	arc4_crypt } }
+};
+
+static int __init arc4_init(void)
+{
+	return crypto_register_alg(&arc4_alg);
+}
+
+static void __exit arc4_exit(void)
+{
+	crypto_unregister_alg(&arc4_alg);
+}
+
+module_init(arc4_init);
+module_exit(arc4_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
+MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
+MODULE_ALIAS("arc4");
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/include/crypto/arc4.h b/include/crypto/arc4.h
new file mode 100644
index 0000000..1423c92
--- /dev/null
+++ b/include/crypto/arc4.h
@@ -0,0 +1,26 @@
+#ifndef __CRYPTO_ARC4_H__
+#define __CRYPTO_ARC4_H__
+
+struct arc4_iv {
+	union {
+		struct arc4_key {
+			u8 key[256];
+			u16 key_len;
+		} key;
+		struct arc4_riv {
+			u8 S[256];
+			u8 x, y;
+		} iv;
+	};
+#define ARC4_TYPE_KEY   0
+#define ARC4_TYPE_IV    1
+	u8 type;
+};
+
+static inline void arc4_setup_iv(struct arc4_iv *iv, const u8 *key, u32 len)
+{
+	memcpy(iv->key.key, key, len);
+	iv->key.key_len = len;
+	iv->type = ARC4_TYPE_KEY;
+}
+#endif
-- 
1.7.0.3

Re: [PATCH v2] crypto: add blkcipher implementation of ARC4

[Herbert Xu]

On Mon, Apr 05, 2010 at 07:04:06PM +0200, Sebastian Andrzej Siewior wrote:
>
> +static void arc4_key_to_iv(const u8 *in_key, u32 key_len, struct arc4_iv *iv)
> +{
> +	int i, j = 0, k = 0;
> +
> +	iv->iv.x = 1;
> +	iv->iv.y = 0;
> +
> +	for (i = 0; i < 256; i++)
> +		iv->iv.S[i] = i;
> +
> +	for (i = 0; i < 256; i++)
> +	{
> +		u8 a = iv->iv.S[i];
> +		j = (j + in_key[k] + a) & 0xff;
> +		iv->iv.S[i] = iv->iv.S[j];
> +		iv->iv.S[j] = a;
> +		if (++k >= key_len)
> +			k = 0;
> +	}
> +}
> +
> +static void arc4_ivsetup(struct arc4_iv *iv)
> +{
> +	struct arc4_iv tmp_iv;
> +
> +	if (iv->type = ARC4_TYPE_IV)
> +		return;
> +
> +	memcpy(&tmp_iv, iv, sizeof(tmp_iv));
> +	arc4_key_to_iv(tmp_iv.key.key, tmp_iv.key.key_len, iv);
> +	iv->type = ARC4_TYPE_IV;
> +}

We need to verify that 1 <= key_len <= 256.

Cheers,
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Re: [PATCH v2] crypto: add blkcipher implementation of ARC4

[Sebastian Andrzej Siewior]

* Herbert Xu | 2010-04-06 20:44:12 [+0800]:

>On Mon, Apr 05, 2010 at 07:04:06PM +0200, Sebastian Andrzej Siewior wrote:
>>
>> +static void arc4_key_to_iv(const u8 *in_key, u32 key_len, struct arc4_iv *iv)
>> +{
>> +	int i, j = 0, k = 0;
>> +
>> +	iv->iv.x = 1;
>> +	iv->iv.y = 0;
>> +
>> +	for (i = 0; i < 256; i++)
>> +		iv->iv.S[i] = i;
>> +
>> +	for (i = 0; i < 256; i++)
>> +	{
>> +		u8 a = iv->iv.S[i];
>> +		j = (j + in_key[k] + a) & 0xff;
>> +		iv->iv.S[i] = iv->iv.S[j];
>> +		iv->iv.S[j] = a;
>> +		if (++k >= key_len)
>> +			k = 0;
>> +	}
>> +}
>> +
>> +static void arc4_ivsetup(struct arc4_iv *iv)
>> +{
>> +	struct arc4_iv tmp_iv;
>> +
>> +	if (iv->type = ARC4_TYPE_IV)
>> +		return;
>> +
>> +	memcpy(&tmp_iv, iv, sizeof(tmp_iv));
>> +	arc4_key_to_iv(tmp_iv.key.key, tmp_iv.key.key_len, iv);
>> +	iv->type = ARC4_TYPE_IV;
>> +}
>
>We need to verify that 1 <= key_len <= 256.
Good point. All arc4 users don't care about return value of setkey so I
think that I just change void to int add the check for the valid key
length.

While we are here, the .setkey() callback could be removed, couldn't it?
It returns 0 even it is doing nothing what looks kinda wrong. However it
shouldn't be called at all since min/max key is 0. Any objections on
that?

>
>Cheers,

Sebastian

Re: [PATCH v2] crypto: add blkcipher implementation of ARC4

[Herbert Xu]

On Tue, Apr 06, 2010 at 10:30:02PM +0200, Sebastian Andrzej Siewior wrote:
>
> Good point. All arc4 users don't care about return value of setkey so I
> think that I just change void to int add the check for the valid key
> length.

Actually, how about getting arc4_setup_iv to do all the legwork
and turn it into a real IV? Then we don't need any checks on the
data path.

> While we are here, the .setkey() callback could be removed, couldn't it?
> It returns 0 even it is doing nothing what looks kinda wrong. However it
> shouldn't be called at all since min/max key is 0. Any objections on
> that?

I'm pretty sure testmgr will call setkey even for keylen = 0, no?

Thanks,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
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Re: [PATCH v2] crypto: add blkcipher implementation of ARC4

[Pavel Roskin]

On Mon, 2010-04-05 at 19:04 +0200, Sebastian Andrzej Siewior wrote:

> +module_init(arc4_init);
> +module_exit(arc4_exit);

I'm feelings uneasy about using the same module init/exit functions
names in arc4blk.c and arc4cip.c.

Even though it doesn't break for me on x86_64 (whether I'm compiling
modules or a solid kernel), and even though the potential name conflict
is temporary until arc4cip.c is removed, it could break on some other
architecture or maybe with another linker.

Let's use arc4blk_init and arc4blk_exit.

-- 
Regards,
Pavel Roskin

Re: [PATCH v2] crypto: add blkcipher implementation of ARC4

[Sebastian Andrzej Siewior]

* Herbert Xu | 2010-04-07 08:31:09 [+0800]:

>On Tue, Apr 06, 2010 at 10:30:02PM +0200, Sebastian Andrzej Siewior wrote:
>>
>> Good point. All arc4 users don't care about return value of setkey so I
>> think that I just change void to int add the check for the valid key
>> length.
>
>Actually, how about getting arc4_setup_iv to do all the legwork
>and turn it into a real IV? Then we don't need any checks on the
>data path.
So arc4_setup_iv() should do what the internal arc4_ivsetup() does and
we change void to int and check the keysize in there right? The problem
here is that we are bounded to *this* implementation of the algorithm
and are not able to replace it with a different implementation. Not that
this is likely to happen for RC4 but it may be true for other stream
ciphers.

>> While we are here, the .setkey() callback could be removed, couldn't it?
>> It returns 0 even it is doing nothing what looks kinda wrong. However it
>> shouldn't be called at all since min/max key is 0. Any objections on
>> that?
>
>I'm pretty sure testmgr will call setkey even for keylen = 0, no?
Prior patch #3 it has no test case so it should not test it at all.
Patch #3 adds a flag in order to distinguish it. You want to look at
patch #3 now :)

>
>Thanks,

Sebastian

Re: [PATCH v2] crypto: add blkcipher implementation of ARC4

[Sebastian Andrzej Siewior]

* Pavel Roskin | 2010-04-07 02:19:55 [-0400]:

>On Mon, 2010-04-05 at 19:04 +0200, Sebastian Andrzej Siewior wrote:
>
>> +module_init(arc4_init);
>> +module_exit(arc4_exit);
>
>I'm feelings uneasy about using the same module init/exit functions
>names in arc4blk.c and arc4cip.c.
>
>Even though it doesn't break for me on x86_64 (whether I'm compiling
>modules or a solid kernel), and even though the potential name conflict
Take a look at
- sd_mod_init
- via_init
- watchdog_init

just to name a few. There is no conflict because those functions are not
global. The only problem you have is in the backtrace since you can't
distinguish them.

Sebastian

Re: [PATCH v2] crypto: add blkcipher implementation of ARC4

[Herbert Xu]

On Wed, Apr 07, 2010 at 10:23:00AM +0200, Sebastian Andrzej Siewior wrote:
>
> So arc4_setup_iv() should do what the internal arc4_ivsetup() does and
> we change void to int and check the keysize in there right? The problem
> here is that we are bounded to *this* implementation of the algorithm
> and are not able to replace it with a different implementation. Not that
> this is likely to happen for RC4 but it may be true for other stream
> ciphers.

By setting an IV we're already requiring the other implementations
use the IV format used by our arc4.  So they would always work with
this arc4_ivsetup anyway.

If and when we do have a piece of hardware that cannot do this
(which I doubt would ever happen, considering how fast arc4 is
already), then we can talk about changing this.

> >I'm pretty sure testmgr will call setkey even for keylen = 0, no?
> Prior patch #3 it has no test case so it should not test it at all.
> Patch #3 adds a flag in order to distinguish it. You want to look at
> patch #3 now :)

I see.

But still we should at least not crash when crypto_blkcipher_setkey
is called.  This might happen in future when we get a user-space
API.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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Re: [PATCH v2] crypto: add blkcipher implementation of ARC4

[Pavel Roskin]

On Wed, 2010-04-07 at 10:29 +0200, Sebastian Andrzej Siewior wrote:
> * Pavel Roskin | 2010-04-07 02:19:55 [-0400]:
> 
> >On Mon, 2010-04-05 at 19:04 +0200, Sebastian Andrzej Siewior wrote:
> >
> >> +module_init(arc4_init);
> >> +module_exit(arc4_exit);
> >
> >I'm feelings uneasy about using the same module init/exit functions
> >names in arc4blk.c and arc4cip.c.
> >
> >Even though it doesn't break for me on x86_64 (whether I'm compiling
> >modules or a solid kernel), and even though the potential name conflict
> Take a look at
> - sd_mod_init
> - via_init
> - watchdog_init
> 
> just to name a few. There is no conflict because those functions are not
> global. The only problem you have is in the backtrace since you can't
> distinguish them.

Touché :-)

-- 
Regards,
Pavel Roskin