[CRYPTO]: Add Tnepres cipher support

This patch adds support for the kerneli 'Tnepres' cipher, a reversed form
of Serpent which was implemented due to problems with the specification.
This allows people to maintain compatibility between old kerneli and
current kernels.

Signed-off-by: Ruben Garcia <ruben@ugr.es>
Signed-off-by: Fruhwirth Clemens <clemens@endorphin.org>
Signed-off-by: James Morris <jmorris@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 207 insertions, 10 deletions

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 6856be2ea9e8cf..d1532071ff94f8 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -125,7 +125,8 @@ config CRYPTO_SERPENT
 	  Serpent cipher algorithm, by Anderson, Biham & Knudsen.
 
 	  Keys are allowed to be from 0 to 256 bits in length, in steps
-	  of 8 bits.
+	  of 8 bits.  Also includes the 'Tnepres' algorithm, a reversed
+	  variant of Serpent for compatibility with old kerneli code.
 
 	  See also:
 	  http://www.cl.cam.ac.uk/~rja14/serpent.html
diff --git a/crypto/serpent.c b/crypto/serpent.c
index 9802b1c54b9ced..4c95ba9c50d328 100644
--- a/crypto/serpent.c
+++ b/crypto/serpent.c
@@ -4,6 +4,10 @@
  * Serpent Cipher Algorithm.
  *
  * Copyright (C) 2002 Dag Arne Osvik <osvik@ii.uib.no>
+ *               2003 Herbert Valerio Riedel <hvr@gnu.org>
+ *
+ * Added tnepres support: Ruben Jesus Garcia Hernandez <ruben@ugr.es>, 18.10.2004
+ *               Based on code by hvr
  *
  * 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
@@ -212,7 +216,8 @@ struct serpent_ctx {
 	u32 expkey[SERPENT_EXPKEY_WORDS];
 };
 
-static int setkey(void *ctx, const u8 *key, unsigned int keylen, u32 *flags)
+
+static int serpent_setkey(void *ctx, const u8 *key, unsigned int keylen, u32 *flags)
 {
 	u32 *k = ((struct serpent_ctx *)ctx)->expkey;
 	u8  *k8 = (u8 *)k;
@@ -362,7 +367,7 @@ static int setkey(void *ctx, const u8 *key, unsigned int keylen, u32 *flags)
 	return 0;
 }
 
-static void encrypt(void *ctx, u8 *dst, const u8 *src)
+static void serpent_encrypt(void *ctx, u8 *dst, const u8 *src)
 {
 	const u32
 		*k = ((struct serpent_ctx *)ctx)->expkey,
@@ -420,7 +425,7 @@ static void encrypt(void *ctx, u8 *dst, const u8 *src)
 	d[3] = cpu_to_le32(r3);
 }
 
-static void decrypt(void *ctx, u8 *dst, const u8 *src)
+static void serpent_decrypt(void *ctx, u8 *dst, const u8 *src)
 {
 	const u32
 		*k = ((struct serpent_ctx *)ctx)->expkey,
@@ -483,18 +488,101 @@ static struct crypto_alg serpent_alg = {
 	.cra_u			=	{ .cipher = {
 	.cia_min_keysize	=	SERPENT_MIN_KEY_SIZE,
 	.cia_max_keysize	=	SERPENT_MAX_KEY_SIZE,
-	.cia_setkey   		= 	setkey,
-	.cia_encrypt 		=	encrypt,
-	.cia_decrypt  		=	decrypt } }
+	.cia_setkey   		= 	serpent_setkey,
+	.cia_encrypt 		=	serpent_encrypt,
+	.cia_decrypt  		=	serpent_decrypt } }
+};
+
+static int tnepres_setkey(void *ctx, const u8 *key, unsigned int keylen, u32 *flags)
+{
+	u8 rev_key[SERPENT_MAX_KEY_SIZE];
+	int i;
+
+	if ((keylen < SERPENT_MIN_KEY_SIZE)
+	    || (keylen > SERPENT_MAX_KEY_SIZE)) {
+		*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+		return -EINVAL;
+	} 
+
+	for (i = 0; i < keylen; ++i)
+		rev_key[keylen - i - 1] = key[i];
+ 
+	return serpent_setkey(ctx, rev_key, keylen, flags);
+}
+
+static void tnepres_encrypt(void *ctx, u8 *dst, const u8 *src)
+{
+	const u32 * const s = (const u32 * const)src;
+	u32 * const d = (u32 * const)dst;
+
+	u32 rs[4], rd[4];
+
+	rs[0] = swab32(s[3]);
+	rs[1] = swab32(s[2]);
+	rs[2] = swab32(s[1]);
+	rs[3] = swab32(s[0]);
+
+	serpent_encrypt(ctx, (u8 *)rd, (u8 *)rs);
+
+	d[0] = swab32(rd[3]);
+	d[1] = swab32(rd[2]);
+	d[2] = swab32(rd[1]);
+	d[3] = swab32(rd[0]);
+}
+
+static void tnepres_decrypt(void *ctx, u8 *dst, const u8 *src)
+{
+	const u32 * const s = (const u32 * const)src;
+	u32 * const d = (u32 * const)dst;
+
+	u32 rs[4], rd[4];
+
+	rs[0] = swab32(s[3]);
+	rs[1] = swab32(s[2]);
+	rs[2] = swab32(s[1]);
+	rs[3] = swab32(s[0]);
+
+	serpent_decrypt(ctx, (u8 *)rd, (u8 *)rs);
+
+	d[0] = swab32(rd[3]);
+	d[1] = swab32(rd[2]);
+	d[2] = swab32(rd[1]);
+	d[3] = swab32(rd[0]);
+}
+
+static struct crypto_alg tnepres_alg = {
+	.cra_name		=	"tnepres",
+	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize		=	SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct serpent_ctx),
+	.cra_module		=	THIS_MODULE,
+	.cra_list		=	LIST_HEAD_INIT(serpent_alg.cra_list),
+	.cra_u			=	{ .cipher = {
+	.cia_min_keysize	=	SERPENT_MIN_KEY_SIZE,
+	.cia_max_keysize	=	SERPENT_MAX_KEY_SIZE,
+	.cia_setkey   		= 	tnepres_setkey,
+	.cia_encrypt 		=	tnepres_encrypt,
+	.cia_decrypt  		=	tnepres_decrypt } }
 };
 
 static int __init init(void)
 {
-	return crypto_register_alg(&serpent_alg);
+	int ret = crypto_register_alg(&serpent_alg);
+
+	if (ret)
+		return ret;
+
+	ret = crypto_register_alg(&tnepres_alg);
+
+	if (ret)
+		crypto_unregister_alg(&serpent_alg);
+
+	return ret;
 }
 
 static void __exit fini(void)
 {
+	crypto_unregister_alg(&tnepres_alg);
 	crypto_unregister_alg(&serpent_alg);
 }
 
@@ -502,5 +590,6 @@ module_init(init);
 module_exit(fini);
 
 MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Serpent Cipher Algorithm");
+MODULE_DESCRIPTION("Serpent and tnepres (kerneli compatible serpent reversed) Cipher Algorithm");
 MODULE_AUTHOR("Dag Arne Osvik <osvik@ii.uib.no>");
+MODULE_ALIAS("tnepres");
diff --git a/crypto/tcrypt.c b/crypto/tcrypt.c
index c23d5ee6946eb1..2d965519c4ab09 100644
--- a/crypto/tcrypt.c
+++ b/crypto/tcrypt.c
@@ -63,7 +63,7 @@ static char *check[] = {
 	"des", "md5", "des3_ede", "rot13", "sha1", "sha256", "blowfish",
 	"twofish", "serpent", "sha384", "sha512", "md4", "aes", "cast6", 
 	"arc4", "michael_mic", "deflate", "crc32c", "tea", "xtea", 
-	"wp512", "wp384", "wp256", NULL
+	"wp512", "wp384", "wp256", "tnepres", NULL
 };
 
 static void
@@ -651,6 +651,10 @@ do_test(void)
 		test_cipher ("serpent", MODE_ECB, ENCRYPT, serpent_enc_tv_template, SERPENT_ENC_TEST_VECTORS);
 		test_cipher ("serpent", MODE_ECB, DECRYPT, serpent_dec_tv_template, SERPENT_DEC_TEST_VECTORS);
 		
+		//TNEPRES
+		test_cipher ("tnepres", MODE_ECB, ENCRYPT, tnepres_enc_tv_template, TNEPRES_ENC_TEST_VECTORS);
+		test_cipher ("tnepres", MODE_ECB, DECRYPT, tnepres_dec_tv_template, TNEPRES_DEC_TEST_VECTORS);
+
 		//AES
 		test_cipher ("aes", MODE_ECB, ENCRYPT, aes_enc_tv_template, AES_ENC_TEST_VECTORS);
 		test_cipher ("aes", MODE_ECB, DECRYPT, aes_dec_tv_template, AES_DEC_TEST_VECTORS);
@@ -739,6 +743,8 @@ do_test(void)
 		break;
 		
 	case 9:
+		test_cipher ("serpent", MODE_ECB, ENCRYPT, serpent_enc_tv_template, SERPENT_ENC_TEST_VECTORS);
+		test_cipher ("serpent", MODE_ECB, DECRYPT, serpent_dec_tv_template, SERPENT_DEC_TEST_VECTORS);
 		break;
 
 	case 10:
@@ -808,6 +814,10 @@ do_test(void)
 		test_hash("wp256", wp256_tv_template, WP256_TEST_VECTORS);
 		break;
 
+	case 25:
+		test_cipher ("tnepres", MODE_ECB, ENCRYPT, tnepres_enc_tv_template, TNEPRES_ENC_TEST_VECTORS);
+		test_cipher ("tnepres", MODE_ECB, DECRYPT, tnepres_dec_tv_template, TNEPRES_DEC_TEST_VECTORS);
+		break;
 
 #ifdef CONFIG_CRYPTO_HMAC
 	case 100:
diff --git a/crypto/tcrypt.h b/crypto/tcrypt.h
index 18370befc652b1..a66df575b79f61 100644
--- a/crypto/tcrypt.h
+++ b/crypto/tcrypt.h
@@ -1444,6 +1444,9 @@ struct cipher_testvec tf_cbc_dec_tv_template[] = {
 #define SERPENT_ENC_TEST_VECTORS	4
 #define SERPENT_DEC_TEST_VECTORS	4
 
+#define TNEPRES_ENC_TEST_VECTORS	4
+#define TNEPRES_DEC_TEST_VECTORS	4
+
 struct cipher_testvec serpent_enc_tv_template[] = 
 {
 	{
@@ -1486,6 +1489,57 @@ struct cipher_testvec serpent_enc_tv_template[] =
 	},
 };
 
+struct cipher_testvec tnepres_enc_tv_template[] = 
+{
+	{ /* KeySize=128, PT=0, I=1 */
+		.input	= { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+		.key    = { 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+		.klen   = 16,
+		.ilen	= 16,
+		.result	= { 0x49, 0xaf, 0xbf, 0xad, 0x9d, 0x5a, 0x34, 0x05, 
+			    0x2c, 0xd8, 0xff, 0xa5, 0x98, 0x6b, 0xd2, 0xdd },
+		.rlen	= 16,
+	}, { /* KeySize=192, PT=0, I=1 */
+		.key	= { 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+		.klen	= 24,
+		.input	= { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+		.ilen	= 16,
+		.result	= { 0xe7, 0x8e, 0x54, 0x02, 0xc7, 0x19, 0x55, 0x68, 
+			    0xac, 0x36, 0x78, 0xf7, 0xa3, 0xf6, 0x0c, 0x66 },
+		.rlen	= 16,
+	}, { /* KeySize=256, PT=0, I=1 */
+		.key	= { 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+		.klen	= 32,
+		.input	= { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+			    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
+		.ilen	= 16,
+		.result	= { 0xab, 0xed, 0x96, 0xe7, 0x66, 0xbf, 0x28, 0xcb, 
+			    0xc0, 0xeb, 0xd2, 0x1a, 0x82, 0xef, 0x08, 0x19 },
+		.rlen	= 16,
+	}, { /* KeySize=256, I=257 */
+	        .key	= { 0x1f, 0x1e, 0x1d, 0x1c, 0x1b, 0x1a, 0x19, 0x18,
+			    0x17, 0x16, 0x15, 0x14, 0x13, 0x12, 0x11, 0x10,
+			    0x0f, 0x0e, 0x0d, 0x0c, 0x0b, 0x0a, 0x09, 0x08,
+			    0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01, 0x00 },
+		.klen	= 32,
+		.input	= { 0x0f, 0x0e, 0x0d, 0x0c, 0x0b, 0x0a, 0x09, 0x08,
+			    0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01, 0x00 },
+		.ilen	= 16,
+		.result	= { 0x5c, 0xe7, 0x1c, 0x70, 0xd2, 0x88, 0x2e, 0x5b, 
+			    0xb8, 0x32, 0xe4, 0x33, 0xf8, 0x9f, 0x26, 0xde },
+		.rlen	= 16,
+	},
+};
+
+
 struct cipher_testvec serpent_dec_tv_template[] = 
 {
 	{
@@ -1528,6 +1582,49 @@ struct cipher_testvec serpent_dec_tv_template[] =
 	},
 };
 
+struct cipher_testvec tnepres_dec_tv_template[] =
+{
+	{
+		.input	= { 0x41, 0xcc, 0x6b, 0x31, 0x59, 0x31, 0x45, 0x97,
+			    0x6d, 0x6f, 0xbb, 0x38, 0x4b, 0x37, 0x21, 0x28 },
+		.ilen	= 16,
+		.result	= { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+			    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
+		.rlen	= 16,
+	}, {
+		.key	= { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+			    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
+		.klen	= 16,
+		.input	= { 0xea, 0xf4, 0xd7, 0xfc, 0xd8, 0x01, 0x34, 0x47, 
+			    0x81, 0x45, 0x0b, 0xfa, 0x0c, 0xd6, 0xad, 0x6e },
+		.ilen	= 16,
+		.result	= { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+			    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
+		.rlen	= 16,
+	}, {
+		.key	= { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+			    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+			    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+			    0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f },
+		.klen	= 32,
+		.input	= { 0x64, 0xa9, 0x1a, 0x37, 0xed, 0x9f, 0xe7, 0x49, 
+			    0xa8, 0x4e, 0x76, 0xd6, 0xf5, 0x0d, 0x78, 0xee },
+		.ilen	= 16,
+		.result	= { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+			    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
+		.rlen	= 16,
+	}, { /* KeySize=128, I=121 */
+		.key	= { [15] = 0x80 },
+		.klen	= 16,
+		.input	= { 0x3d, 0xda, 0xbf, 0xc0, 0x06, 0xda, 0xab, 0x06, 
+			    0x46, 0x2a, 0xf4, 0xef, 0x81, 0x54, 0x4e, 0x26 },
+		.ilen	= 16,
+		.result	= { [0 ... 15] = 0x00 },
+		.rlen	= 16,
+	},
+};
+
+
 /* Cast6 test vectors from RFC 2612 */
 #define CAST6_ENC_TEST_VECTORS	3
 #define CAST6_DEC_TEST_VECTORS  3