[CRYPTO]: Fix XTEA implementation

The XTEA implementation was incorrect due to a misinterpretation of
operator precedence.  Because of the wide-spread nature of this
error, the erroneous implementation will be kept, albeit under the
new name of XETA.

Signed-off-by: Aaron Grothe <ajgrothe@yahoo.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/crypto/api-intro.txt

@@ -223,6 +223,7 @@ CAST5 algorithm contributors:
 
 TEA/XTEA algorithm contributors:
   Aaron Grothe
+  Michael Ringe
 
 Khazad algorithm contributors:
   Aaron Grothe

crypto/Kconfig

@@ -219,7 +219,7 @@ config CRYPTO_CAST6
 	  described in RFC2612.
 
 config CRYPTO_TEA
-	tristate "TEA and XTEA cipher algorithms"
+	tristate "TEA, XTEA and XETA cipher algorithms"
 	depends on CRYPTO
 	help
 	  TEA cipher algorithm.
@@ -232,6 +232,9 @@ config CRYPTO_TEA
 	  the TEA algorithm to address a potential key weakness
 	  in the TEA algorithm.
 
+	  Xtendend Encryption Tiny Algorithm is a mis-implementation 
+	  of the XTEA algorithm for compatibility purposes.
+
 config CRYPTO_ARC4
 	tristate "ARC4 cipher algorithm"
 	depends on CRYPTO

crypto/tcrypt.c

@@ -72,7 +72,7 @@ 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",
-	"khazad", "wp512", "wp384", "wp256", "tnepres", NULL
+	"khazad", "wp512", "wp384", "wp256", "tnepres", "xeta", NULL
 };
 
 static void hexdump(unsigned char *buf, unsigned int len)
@@ -859,6 +859,10 @@ static void do_test(void)
 		test_cipher ("anubis", MODE_CBC, ENCRYPT, anubis_cbc_enc_tv_template, ANUBIS_CBC_ENC_TEST_VECTORS);
 		test_cipher ("anubis", MODE_CBC, DECRYPT, anubis_cbc_dec_tv_template, ANUBIS_CBC_ENC_TEST_VECTORS);
 
+		//XETA
+		test_cipher ("xeta", MODE_ECB, ENCRYPT, xeta_enc_tv_template, XETA_ENC_TEST_VECTORS);
+		test_cipher ("xeta", MODE_ECB, DECRYPT, xeta_dec_tv_template, XETA_DEC_TEST_VECTORS);
+
 		test_hash("sha384", sha384_tv_template, SHA384_TEST_VECTORS);
 		test_hash("sha512", sha512_tv_template, SHA512_TEST_VECTORS);
 		test_hash("wp512", wp512_tv_template, WP512_TEST_VECTORS);
@@ -1016,6 +1020,11 @@ static void do_test(void)
 	case 29:
 		test_hash("tgr128", tgr128_tv_template, TGR128_TEST_VECTORS);
 		break;
+		
+	case 30:
+		test_cipher ("xeta", MODE_ECB, ENCRYPT, xeta_enc_tv_template, XETA_ENC_TEST_VECTORS);
+		test_cipher ("xeta", MODE_ECB, DECRYPT, xeta_dec_tv_template, XETA_DEC_TEST_VECTORS);
+		break;
 
 #ifdef CONFIG_CRYPTO_HMAC
 	case 100:

crypto/tcrypt.h

@@ -2211,7 +2211,7 @@ static struct cipher_testvec xtea_enc_tv_template[] = {
 		.klen	= 16,
 		.input  = { [0 ... 8] = 0x00 },
 		.ilen	= 8,
-		.result	= { 0xaa, 0x22, 0x96, 0xe5, 0x6c, 0x61, 0xf3, 0x45 },
+		.result	= { 0xd8, 0xd4, 0xe9, 0xde, 0xd9, 0x1e, 0x13, 0xf7 },
 		.rlen	= 8,
 	}, {
 		.key	= { 0x2b, 0x02, 0x05, 0x68, 0x06, 0x14, 0x49, 0x76,
@@ -2219,31 +2219,31 @@ static struct cipher_testvec xtea_enc_tv_template[] = {
 		.klen	= 16,
 		.input	= { 0x74, 0x65, 0x73, 0x74, 0x20, 0x6d, 0x65, 0x2e },
 		.ilen	= 8,
-		.result	= { 0x82, 0x3e, 0xeb, 0x35, 0xdc, 0xdd, 0xd9, 0xc3 },
+		.result	= { 0x94, 0xeb, 0xc8, 0x96, 0x84, 0x6a, 0x49, 0xa8 },
 		.rlen	= 8,
 	}, {
 		.key	= { 0x09, 0x65, 0x43, 0x11, 0x66, 0x44, 0x39, 0x25,
 			    0x51, 0x3a, 0x16, 0x10, 0x0a, 0x08, 0x12, 0x6e },
 		.klen	= 16,
-		.input	= { 0x6c, 0x6f, 0x6e, 0x67, 0x65, 0x72, 0x5f, 0x74,
+		.input	= { 0x3e, 0xce, 0xae, 0x22, 0x60, 0x56, 0xa8, 0x9d,
 			    0x65, 0x73, 0x74, 0x5f, 0x76, 0x65, 0x63, 0x74 },
 		.ilen	= 16,
-		.result	= { 0xe2, 0x04, 0xdb, 0xf2, 0x89, 0x85, 0x9e, 0xea,
+		.result	= { 0xe2, 0x04, 0xdb, 0xf2, 0x89, 0x85, 0x9e, 0xea, 
 			    0x61, 0x35, 0xaa, 0xed, 0xb5, 0xcb, 0x71, 0x2c },
 		.rlen	= 16,
 	}, {
 		.key	= { 0x4d, 0x76, 0x32, 0x17, 0x05, 0x3f, 0x75, 0x2c,
 			    0x5d, 0x04, 0x16, 0x36, 0x15, 0x72, 0x63, 0x2f },
 		.klen	= 16,
-		.input	= { 0x54, 0x65, 0x61, 0x20, 0x69, 0x73, 0x20, 0x67,
+		.input	= { 0x54, 0x65, 0x61, 0x20, 0x69, 0x73, 0x20, 0x67, 
-			    0x6f, 0x6f, 0x64, 0x20, 0x66, 0x6f, 0x72, 0x20,
+			    0x6f, 0x6f, 0x64, 0x20, 0x66, 0x6f, 0x72, 0x20, 
-			    0x79, 0x6f, 0x75, 0x21, 0x21, 0x21, 0x20, 0x72,
+			    0x79, 0x6f, 0x75, 0x21, 0x21, 0x21, 0x20, 0x72, 
 			    0x65, 0x61, 0x6c, 0x6c, 0x79, 0x21, 0x21, 0x21 },
 		.ilen	= 32,
-		.result	= { 0x0b, 0x03, 0xcd, 0x8a, 0xbe, 0x95, 0xfd, 0xb1,
+		.result	= { 0x99, 0x81, 0x9f, 0x5d, 0x6f, 0x4b, 0x31, 0x3a,
-			    0xc1, 0x44, 0x91, 0x0b, 0xa5, 0xc9, 0x1b, 0xb4,
+			    0x86, 0xff, 0x6f, 0xd0, 0xe3, 0x87, 0x70, 0x07,
-			    0xa9, 0xda, 0x1e, 0x9e, 0xb1, 0x3e, 0x2a, 0x8f,
+			    0x4d, 0xb8, 0xcf, 0xf3, 0x99, 0x50, 0xb3, 0xd4,
-			    0xea, 0xa5, 0x6a, 0x85, 0xd1, 0xf4, 0xa8, 0xa5 },
+			    0x73, 0xa2, 0xfa, 0xc9, 0x16, 0x59, 0x5d, 0x81 },
 		.rlen	= 32,
 	}
 };
@@ -2252,7 +2252,7 @@ static struct cipher_testvec xtea_dec_tv_template[] = {
 	{
 		.key    = { [0 ... 15] = 0x00 },
 		.klen	= 16,
-		.input	= { 0xaa, 0x22, 0x96, 0xe5, 0x6c, 0x61, 0xf3, 0x45 },
+		.input	= { 0xd8, 0xd4, 0xe9, 0xde, 0xd9, 0x1e, 0x13, 0xf7 },
 		.ilen	= 8,
 		.result = { [0 ... 8] = 0x00 },
 		.rlen	= 8,
@@ -2260,7 +2260,7 @@ static struct cipher_testvec xtea_dec_tv_template[] = {
 		.key	= { 0x2b, 0x02, 0x05, 0x68, 0x06, 0x14, 0x49, 0x76,
 			    0x77, 0x5d, 0x0e, 0x26, 0x6c, 0x28, 0x78, 0x43 },
 		.klen	= 16,
-		.input	= { 0x82, 0x3e, 0xeb, 0x35, 0xdc, 0xdd, 0xd9, 0xc3 },
+		.input	= { 0x94, 0xeb, 0xc8, 0x96, 0x84, 0x6a, 0x49, 0xa8 },
 		.ilen	= 8,
 		.result	= { 0x74, 0x65, 0x73, 0x74, 0x20, 0x6d, 0x65, 0x2e },
 		.rlen	= 8,
@@ -2268,24 +2268,24 @@ static struct cipher_testvec xtea_dec_tv_template[] = {
 		.key	= { 0x09, 0x65, 0x43, 0x11, 0x66, 0x44, 0x39, 0x25,
 			    0x51, 0x3a, 0x16, 0x10, 0x0a, 0x08, 0x12, 0x6e },
 		.klen	= 16,
-		.input	= { 0xe2, 0x04, 0xdb, 0xf2, 0x89, 0x85, 0x9e, 0xea,
+		.input	= { 0x3e, 0xce, 0xae, 0x22, 0x60, 0x56, 0xa8, 0x9d,
-			    0x61, 0x35, 0xaa, 0xed, 0xb5, 0xcb, 0x71, 0x2c },
+			    0x77, 0x4d, 0xd4, 0xb4, 0x87, 0x24, 0xe3, 0x9a },
 		.ilen	= 16,
-		.result	= { 0x6c, 0x6f, 0x6e, 0x67, 0x65, 0x72, 0x5f, 0x74,
+		.result	= { 0x6c, 0x6f, 0x6e, 0x67, 0x65, 0x72, 0x5f, 0x74, 
 			    0x65, 0x73, 0x74, 0x5f, 0x76, 0x65, 0x63, 0x74 },
 		.rlen	= 16,
 	}, {
 		.key	= { 0x4d, 0x76, 0x32, 0x17, 0x05, 0x3f, 0x75, 0x2c,
 			    0x5d, 0x04, 0x16, 0x36, 0x15, 0x72, 0x63, 0x2f },
 		.klen	= 16,
-		.input	= { 0x0b, 0x03, 0xcd, 0x8a, 0xbe, 0x95, 0xfd, 0xb1,
+		.input	= { 0x99, 0x81, 0x9f, 0x5d, 0x6f, 0x4b, 0x31, 0x3a,
-			    0xc1, 0x44, 0x91, 0x0b, 0xa5, 0xc9, 0x1b, 0xb4,
+			    0x86, 0xff, 0x6f, 0xd0, 0xe3, 0x87, 0x70, 0x07,
-			    0xa9, 0xda, 0x1e, 0x9e, 0xb1, 0x3e, 0x2a, 0x8f,
+			    0x4d, 0xb8, 0xcf, 0xf3, 0x99, 0x50, 0xb3, 0xd4,
-			    0xea, 0xa5, 0x6a, 0x85, 0xd1, 0xf4, 0xa8, 0xa5 },
+			    0x73, 0xa2, 0xfa, 0xc9, 0x16, 0x59, 0x5d, 0x81 },
 		.ilen	= 32,
-		.result	= { 0x54, 0x65, 0x61, 0x20, 0x69, 0x73, 0x20, 0x67,
+		.result	= { 0x54, 0x65, 0x61, 0x20, 0x69, 0x73, 0x20, 0x67, 
-			    0x6f, 0x6f, 0x64, 0x20, 0x66, 0x6f, 0x72, 0x20,
+			    0x6f, 0x6f, 0x64, 0x20, 0x66, 0x6f, 0x72, 0x20, 
-			    0x79, 0x6f, 0x75, 0x21, 0x21, 0x21, 0x20, 0x72,
+			    0x79, 0x6f, 0x75, 0x21, 0x21, 0x21, 0x20, 0x72, 
 			    0x65, 0x61, 0x6c, 0x6c, 0x79, 0x21, 0x21, 0x21 },
 		.rlen	= 32,
 	}
@@ -2594,6 +2594,98 @@ static struct cipher_testvec anubis_cbc_dec_tv_template[] = {
 	},
 };
 
+/* 
+ * XETA test vectors 
+ */
+#define XETA_ENC_TEST_VECTORS	4
+#define XETA_DEC_TEST_VECTORS	4
+
+static struct cipher_testvec xeta_enc_tv_template[] = {
+	{
+		.key    = { [0 ... 15] = 0x00 },
+		.klen	= 16,
+		.input  = { [0 ... 8] = 0x00 },
+		.ilen	= 8,
+		.result	= { 0xaa, 0x22, 0x96, 0xe5, 0x6c, 0x61, 0xf3, 0x45 },
+		.rlen	= 8,
+	}, {
+		.key	= { 0x2b, 0x02, 0x05, 0x68, 0x06, 0x14, 0x49, 0x76,
+			    0x77, 0x5d, 0x0e, 0x26, 0x6c, 0x28, 0x78, 0x43 },
+		.klen	= 16,
+		.input	= { 0x74, 0x65, 0x73, 0x74, 0x20, 0x6d, 0x65, 0x2e },
+		.ilen	= 8,
+		.result	= { 0x82, 0x3e, 0xeb, 0x35, 0xdc, 0xdd, 0xd9, 0xc3 },
+		.rlen	= 8,
+	}, {
+		.key	= { 0x09, 0x65, 0x43, 0x11, 0x66, 0x44, 0x39, 0x25,
+			    0x51, 0x3a, 0x16, 0x10, 0x0a, 0x08, 0x12, 0x6e },
+		.klen	= 16,
+		.input	= { 0x6c, 0x6f, 0x6e, 0x67, 0x65, 0x72, 0x5f, 0x74, 
+			    0x65, 0x73, 0x74, 0x5f, 0x76, 0x65, 0x63, 0x74 },
+		.ilen	= 16,
+		.result	= { 0xe2, 0x04, 0xdb, 0xf2, 0x89, 0x85, 0x9e, 0xea, 
+			    0x61, 0x35, 0xaa, 0xed, 0xb5, 0xcb, 0x71, 0x2c },
+		.rlen	= 16,
+	}, {
+		.key	= { 0x4d, 0x76, 0x32, 0x17, 0x05, 0x3f, 0x75, 0x2c,
+			    0x5d, 0x04, 0x16, 0x36, 0x15, 0x72, 0x63, 0x2f },
+		.klen	= 16,
+		.input	= { 0x54, 0x65, 0x61, 0x20, 0x69, 0x73, 0x20, 0x67, 
+			    0x6f, 0x6f, 0x64, 0x20, 0x66, 0x6f, 0x72, 0x20, 
+			    0x79, 0x6f, 0x75, 0x21, 0x21, 0x21, 0x20, 0x72, 
+			    0x65, 0x61, 0x6c, 0x6c, 0x79, 0x21, 0x21, 0x21 },
+		.ilen	= 32,
+		.result	= { 0x0b, 0x03, 0xcd, 0x8a, 0xbe, 0x95, 0xfd, 0xb1, 
+			    0xc1, 0x44, 0x91, 0x0b, 0xa5, 0xc9, 0x1b, 0xb4, 
+			    0xa9, 0xda, 0x1e, 0x9e, 0xb1, 0x3e, 0x2a, 0x8f, 
+			    0xea, 0xa5, 0x6a, 0x85, 0xd1, 0xf4, 0xa8, 0xa5 },
+		.rlen	= 32,
+	}
+};
+
+static struct cipher_testvec xeta_dec_tv_template[] = {
+	{
+		.key    = { [0 ... 15] = 0x00 },
+		.klen	= 16,
+		.input	= { 0xaa, 0x22, 0x96, 0xe5, 0x6c, 0x61, 0xf3, 0x45 },
+		.ilen	= 8,
+		.result = { [0 ... 8] = 0x00 },
+		.rlen	= 8,
+	}, {
+		.key	= { 0x2b, 0x02, 0x05, 0x68, 0x06, 0x14, 0x49, 0x76,
+			    0x77, 0x5d, 0x0e, 0x26, 0x6c, 0x28, 0x78, 0x43 },
+		.klen	= 16,
+		.input	= { 0x82, 0x3e, 0xeb, 0x35, 0xdc, 0xdd, 0xd9, 0xc3 },
+		.ilen	= 8,
+		.result	= { 0x74, 0x65, 0x73, 0x74, 0x20, 0x6d, 0x65, 0x2e },
+		.rlen	= 8,
+	}, {
+		.key	= { 0x09, 0x65, 0x43, 0x11, 0x66, 0x44, 0x39, 0x25,
+			    0x51, 0x3a, 0x16, 0x10, 0x0a, 0x08, 0x12, 0x6e },
+		.klen	= 16,
+		.input	= { 0xe2, 0x04, 0xdb, 0xf2, 0x89, 0x85, 0x9e, 0xea, 
+			    0x61, 0x35, 0xaa, 0xed, 0xb5, 0xcb, 0x71, 0x2c },
+		.ilen	= 16,
+		.result	= { 0x6c, 0x6f, 0x6e, 0x67, 0x65, 0x72, 0x5f, 0x74, 
+			    0x65, 0x73, 0x74, 0x5f, 0x76, 0x65, 0x63, 0x74 },
+		.rlen	= 16,
+	}, {
+		.key	= { 0x4d, 0x76, 0x32, 0x17, 0x05, 0x3f, 0x75, 0x2c,
+			    0x5d, 0x04, 0x16, 0x36, 0x15, 0x72, 0x63, 0x2f },
+		.klen	= 16,
+		.input	= { 0x0b, 0x03, 0xcd, 0x8a, 0xbe, 0x95, 0xfd, 0xb1, 
+			    0xc1, 0x44, 0x91, 0x0b, 0xa5, 0xc9, 0x1b, 0xb4, 
+			    0xa9, 0xda, 0x1e, 0x9e, 0xb1, 0x3e, 0x2a, 0x8f, 
+			    0xea, 0xa5, 0x6a, 0x85, 0xd1, 0xf4, 0xa8, 0xa5 },
+		.ilen	= 32,
+		.result	= { 0x54, 0x65, 0x61, 0x20, 0x69, 0x73, 0x20, 0x67, 
+			    0x6f, 0x6f, 0x64, 0x20, 0x66, 0x6f, 0x72, 0x20, 
+			    0x79, 0x6f, 0x75, 0x21, 0x21, 0x21, 0x20, 0x72, 
+			    0x65, 0x61, 0x6c, 0x6c, 0x79, 0x21, 0x21, 0x21 },
+		.rlen	= 32,
+	}
+};
+
 /*
  * Compression stuff.
  */

crypto/tea.c

@@ -1,11 +1,15 @@
 /* 
  * Cryptographic API.
  *
- * TEA and Xtended TEA Algorithms
+ * TEA, XTEA, and XETA crypto alogrithms
  *
  * The TEA and Xtended TEA algorithms were developed by David Wheeler 
  * and Roger Needham at the Computer Laboratory of Cambridge University.
  *
+ * Due to the order of evaluation in XTEA many people have incorrectly
+ * implemented it.  XETA (XTEA in the wrong order), exists for
+ * compatibility with these implementations.
+ *
  * Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com
  *
  * This program is free software; you can redistribute it and/or modify
@@ -153,9 +157,9 @@ static void xtea_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
 	z = u32_in (src + 4);
 
 	while (sum != limit) {
-		y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3]; 
+		y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]); 
 		sum += XTEA_DELTA;
-		z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3]; 
+		z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]); 
 	}
 	
 	u32_out (dst, y);
@@ -174,6 +178,51 @@ static void xtea_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
 
 	sum = XTEA_DELTA * XTEA_ROUNDS;
 
+	while (sum) {
+		z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
+		sum -= XTEA_DELTA;
+		y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
+	}
+	
+	u32_out (dst, y);
+	u32_out (dst + 4, z);
+
+}
+
+
+static void xeta_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
+{ 
+
+	u32 y, z, sum = 0;
+	u32 limit = XTEA_DELTA * XTEA_ROUNDS;
+
+	struct xtea_ctx *ctx = ctx_arg;
+
+	y = u32_in (src);
+	z = u32_in (src + 4);
+
+	while (sum != limit) {
+		y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
+		sum += XTEA_DELTA;
+		z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
+	}
+	
+	u32_out (dst, y);
+	u32_out (dst + 4, z);
+
+}
+
+static void xeta_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
+{ 
+
+	u32 y, z, sum;
+	struct tea_ctx *ctx = ctx_arg;
+
+	y = u32_in (src);
+	z = u32_in (src + 4);
+
+	sum = XTEA_DELTA * XTEA_ROUNDS;
+
 	while (sum) {
 		z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
 		sum -= XTEA_DELTA;
@@ -215,6 +264,21 @@ static struct crypto_alg xtea_alg = {
 	.cia_decrypt		=	xtea_decrypt } }
 };
 
+static struct crypto_alg xeta_alg = {
+	.cra_name		=	"xeta",
+	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize		=	XTEA_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof (struct xtea_ctx),
+	.cra_module		=	THIS_MODULE,
+	.cra_list		=	LIST_HEAD_INIT(xtea_alg.cra_list),
+	.cra_u			=	{ .cipher = {
+	.cia_min_keysize	=	XTEA_KEY_SIZE,
+	.cia_max_keysize	=	XTEA_KEY_SIZE,
+	.cia_setkey		= 	xtea_setkey,
+	.cia_encrypt		=	xeta_encrypt,
+	.cia_decrypt		=	xeta_decrypt } }
+};
+
 static int __init init(void)
 {
 	int ret = 0;
@@ -229,6 +293,13 @@ static int __init init(void)
 		goto out;
 	}
 
+	ret = crypto_register_alg(&xeta_alg);
+	if (ret < 0) {
+		crypto_unregister_alg(&tea_alg);
+		crypto_unregister_alg(&xtea_alg);
+		goto out;
+	}
+
 out:	
 	return ret;
 }
@@ -237,12 +308,14 @@ static void __exit fini(void)
 {
 	crypto_unregister_alg(&tea_alg);
 	crypto_unregister_alg(&xtea_alg);
+	crypto_unregister_alg(&xeta_alg);
 }
 
 MODULE_ALIAS("xtea");
+MODULE_ALIAS("xeta");
 
 module_init(init);
 module_exit(fini);
 
 MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("TEA & XTEA Cryptographic Algorithms");
+MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");