linux-imx

// SPDX-License-Identifier: GPL-2.0-or-later

/* 

 * Cryptographic API.

 *

 * 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

 */

​

#include <linux/init.h>

#include <linux/module.h>

#include <linux/mm.h>

#include <asm/byteorder.h>

#include <linux/crypto.h>

#include <linux/types.h>

​

#define TEA_KEY_SIZE        16

#define TEA_BLOCK_SIZE      8

#define TEA_ROUNDS      32

#define TEA_DELTA       0x9e3779b9

​

#define XTEA_KEY_SIZE       16

#define XTEA_BLOCK_SIZE     8

#define XTEA_ROUNDS     32

#define XTEA_DELTA      0x9e3779b9

​

struct tea_ctx {

    u32 KEY[4];

};

​

struct xtea_ctx {

    u32 KEY[4];

};

​

static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key,

              unsigned int key_len)

{

    struct tea_ctx *ctx = crypto_tfm_ctx(tfm);

    const __le32 *key = (const __le32 *)in_key;

​

    ctx->KEY[0] = le32_to_cpu(key[0]);

    ctx->KEY[1] = le32_to_cpu(key[1]);

    ctx->KEY[2] = le32_to_cpu(key[2]);

    ctx->KEY[3] = le32_to_cpu(key[3]);

​

    return 0; 

​

}

​

static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)

{

    u32 y, z, n, sum = 0;

    u32 k0, k1, k2, k3;

    struct tea_ctx *ctx = crypto_tfm_ctx(tfm);

    const __le32 *in = (const __le32 *)src;

    __le32 *out = (__le32 *)dst;

​

    y = le32_to_cpu(in[0]);

    z = le32_to_cpu(in[1]);

​

    k0 = ctx->KEY[0];

    k1 = ctx->KEY[1];

    k2 = ctx->KEY[2];

    k3 = ctx->KEY[3];

​

    n = TEA_ROUNDS;

​

    while (n-- > 0) {

        sum += TEA_DELTA;

        y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);

        z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);

    }

    out[0] = cpu_to_le32(y);

    out[1] = cpu_to_le32(z);

}

​

static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)

{

    u32 y, z, n, sum;

    u32 k0, k1, k2, k3;

    struct tea_ctx *ctx = crypto_tfm_ctx(tfm);

    const __le32 *in = (const __le32 *)src;

    __le32 *out = (__le32 *)dst;

​