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321 lines
6.5 KiB
321 lines
6.5 KiB
/*
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* Cryptographic API.
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*
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* TEA, XTEA, and XETA crypto alogrithms
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*
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* The TEA and Xtended TEA algorithms were developed by David Wheeler
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* and Roger Needham at the Computer Laboratory of Cambridge University.
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*
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* Due to the order of evaluation in XTEA many people have incorrectly
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* implemented it. XETA (XTEA in the wrong order), exists for
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* compatibility with these implementations.
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*
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* Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <asm/scatterlist.h>
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#include <linux/crypto.h>
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#define TEA_KEY_SIZE 16
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#define TEA_BLOCK_SIZE 8
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#define TEA_ROUNDS 32
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#define TEA_DELTA 0x9e3779b9
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#define XTEA_KEY_SIZE 16
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#define XTEA_BLOCK_SIZE 8
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#define XTEA_ROUNDS 32
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#define XTEA_DELTA 0x9e3779b9
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#define u32_in(x) le32_to_cpu(*(const __le32 *)(x))
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#define u32_out(to, from) (*(__le32 *)(to) = cpu_to_le32(from))
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struct tea_ctx {
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u32 KEY[4];
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};
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struct xtea_ctx {
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u32 KEY[4];
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};
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static int tea_setkey(void *ctx_arg, const u8 *in_key,
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unsigned int key_len, u32 *flags)
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{
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struct tea_ctx *ctx = ctx_arg;
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if (key_len != 16)
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{
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*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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ctx->KEY[0] = u32_in (in_key);
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ctx->KEY[1] = u32_in (in_key + 4);
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ctx->KEY[2] = u32_in (in_key + 8);
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ctx->KEY[3] = u32_in (in_key + 12);
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return 0;
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}
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static void tea_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
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{
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u32 y, z, n, sum = 0;
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u32 k0, k1, k2, k3;
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struct tea_ctx *ctx = ctx_arg;
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y = u32_in (src);
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z = u32_in (src + 4);
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k0 = ctx->KEY[0];
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k1 = ctx->KEY[1];
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k2 = ctx->KEY[2];
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k3 = ctx->KEY[3];
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n = TEA_ROUNDS;
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while (n-- > 0) {
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sum += TEA_DELTA;
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y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
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z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
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}
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u32_out (dst, y);
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u32_out (dst + 4, z);
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}
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static void tea_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
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{
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u32 y, z, n, sum;
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u32 k0, k1, k2, k3;
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struct tea_ctx *ctx = ctx_arg;
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y = u32_in (src);
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z = u32_in (src + 4);
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k0 = ctx->KEY[0];
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k1 = ctx->KEY[1];
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k2 = ctx->KEY[2];
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k3 = ctx->KEY[3];
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sum = TEA_DELTA << 5;
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n = TEA_ROUNDS;
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while (n-- > 0) {
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z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
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y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
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sum -= TEA_DELTA;
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}
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u32_out (dst, y);
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u32_out (dst + 4, z);
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}
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static int xtea_setkey(void *ctx_arg, const u8 *in_key,
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unsigned int key_len, u32 *flags)
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{
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struct xtea_ctx *ctx = ctx_arg;
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if (key_len != 16)
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{
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*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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ctx->KEY[0] = u32_in (in_key);
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ctx->KEY[1] = u32_in (in_key + 4);
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ctx->KEY[2] = u32_in (in_key + 8);
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ctx->KEY[3] = u32_in (in_key + 12);
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return 0;
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}
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static void xtea_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
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{
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u32 y, z, sum = 0;
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u32 limit = XTEA_DELTA * XTEA_ROUNDS;
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struct xtea_ctx *ctx = ctx_arg;
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y = u32_in (src);
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z = u32_in (src + 4);
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while (sum != limit) {
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y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]);
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sum += XTEA_DELTA;
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z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]);
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}
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u32_out (dst, y);
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u32_out (dst + 4, z);
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}
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static void xtea_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
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{
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u32 y, z, sum;
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struct tea_ctx *ctx = ctx_arg;
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y = u32_in (src);
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z = u32_in (src + 4);
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sum = XTEA_DELTA * XTEA_ROUNDS;
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while (sum) {
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z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
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sum -= XTEA_DELTA;
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y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
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}
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u32_out (dst, y);
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u32_out (dst + 4, z);
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}
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static void xeta_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
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{
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u32 y, z, sum = 0;
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u32 limit = XTEA_DELTA * XTEA_ROUNDS;
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struct xtea_ctx *ctx = ctx_arg;
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y = u32_in (src);
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z = u32_in (src + 4);
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while (sum != limit) {
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y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
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sum += XTEA_DELTA;
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z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
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}
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u32_out (dst, y);
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u32_out (dst + 4, z);
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}
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static void xeta_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
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{
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u32 y, z, sum;
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struct tea_ctx *ctx = ctx_arg;
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y = u32_in (src);
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z = u32_in (src + 4);
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sum = XTEA_DELTA * XTEA_ROUNDS;
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while (sum) {
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z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
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sum -= XTEA_DELTA;
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y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3];
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}
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u32_out (dst, y);
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u32_out (dst + 4, z);
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}
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static struct crypto_alg tea_alg = {
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.cra_name = "tea",
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = TEA_BLOCK_SIZE,
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.cra_ctxsize = sizeof (struct tea_ctx),
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.cra_module = THIS_MODULE,
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.cra_list = LIST_HEAD_INIT(tea_alg.cra_list),
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.cra_u = { .cipher = {
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.cia_min_keysize = TEA_KEY_SIZE,
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.cia_max_keysize = TEA_KEY_SIZE,
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.cia_setkey = tea_setkey,
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.cia_encrypt = tea_encrypt,
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.cia_decrypt = tea_decrypt } }
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};
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static struct crypto_alg xtea_alg = {
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.cra_name = "xtea",
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = XTEA_BLOCK_SIZE,
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.cra_ctxsize = sizeof (struct xtea_ctx),
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.cra_module = THIS_MODULE,
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.cra_list = LIST_HEAD_INIT(xtea_alg.cra_list),
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.cra_u = { .cipher = {
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.cia_min_keysize = XTEA_KEY_SIZE,
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.cia_max_keysize = XTEA_KEY_SIZE,
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.cia_setkey = xtea_setkey,
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.cia_encrypt = xtea_encrypt,
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.cia_decrypt = xtea_decrypt } }
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};
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static struct crypto_alg xeta_alg = {
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.cra_name = "xeta",
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = XTEA_BLOCK_SIZE,
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.cra_ctxsize = sizeof (struct xtea_ctx),
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.cra_module = THIS_MODULE,
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.cra_list = LIST_HEAD_INIT(xtea_alg.cra_list),
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.cra_u = { .cipher = {
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.cia_min_keysize = XTEA_KEY_SIZE,
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.cia_max_keysize = XTEA_KEY_SIZE,
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.cia_setkey = xtea_setkey,
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.cia_encrypt = xeta_encrypt,
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.cia_decrypt = xeta_decrypt } }
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};
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static int __init init(void)
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{
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int ret = 0;
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ret = crypto_register_alg(&tea_alg);
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if (ret < 0)
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goto out;
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ret = crypto_register_alg(&xtea_alg);
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if (ret < 0) {
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crypto_unregister_alg(&tea_alg);
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goto out;
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}
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ret = crypto_register_alg(&xeta_alg);
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if (ret < 0) {
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crypto_unregister_alg(&tea_alg);
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crypto_unregister_alg(&xtea_alg);
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goto out;
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}
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out:
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return ret;
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}
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static void __exit fini(void)
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{
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crypto_unregister_alg(&tea_alg);
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crypto_unregister_alg(&xtea_alg);
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crypto_unregister_alg(&xeta_alg);
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}
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MODULE_ALIAS("xtea");
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MODULE_ALIAS("xeta");
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module_init(init);
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module_exit(fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");
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