git/linux-cryptodev-2.6
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git synced 2026-04-18 03:23:53 -04:00
Code Issues Packages Projects Releases Wiki Activity

[CRYPTO]: Fix XTEA implementation

Browse Source 
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>
This commit is contained in:
Aaron Grothe
2005-09-01 17:42:46 -07:00
committed by David S. Miller
parent 75c80c382f
commit fb4f10ed50
5 changed files with 207 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

81
crypto/tea.c
View File

@@ -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");