linux/crypto/sm4_generic.c
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   1// SPDX-License-Identifier: GPL-2.0
   2
   3/*
   4 * SM4 Cipher Algorithm.
   5 *
   6 * Copyright (C) 2018 ARM Limited or its affiliates.
   7 * All rights reserved.
   8 */
   9
  10#include <crypto/sm4.h>
  11#include <linux/module.h>
  12#include <linux/init.h>
  13#include <linux/types.h>
  14#include <linux/errno.h>
  15#include <linux/crypto.h>
  16#include <asm/byteorder.h>
  17#include <asm/unaligned.h>
  18
  19static const u32 fk[4] = {
  20        0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
  21};
  22
  23static const u8 sbox[256] = {
  24        0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7,
  25        0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05,
  26        0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3,
  27        0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
  28        0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a,
  29        0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62,
  30        0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95,
  31        0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6,
  32        0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba,
  33        0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8,
  34        0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b,
  35        0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35,
  36        0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2,
  37        0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87,
  38        0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52,
  39        0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e,
  40        0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5,
  41        0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1,
  42        0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55,
  43        0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3,
  44        0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60,
  45        0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f,
  46        0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f,
  47        0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51,
  48        0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f,
  49        0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8,
  50        0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd,
  51        0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0,
  52        0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e,
  53        0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84,
  54        0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20,
  55        0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48
  56};
  57
  58static const u32 ck[] = {
  59        0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
  60        0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
  61        0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
  62        0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
  63        0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
  64        0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
  65        0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
  66        0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
  67};
  68
  69static u32 sm4_t_non_lin_sub(u32 x)
  70{
  71        int i;
  72        u8 *b = (u8 *)&x;
  73
  74        for (i = 0; i < 4; ++i)
  75                b[i] = sbox[b[i]];
  76
  77        return x;
  78}
  79
  80static u32 sm4_key_lin_sub(u32 x)
  81{
  82        return x ^ rol32(x, 13) ^ rol32(x, 23);
  83
  84}
  85
  86static u32 sm4_enc_lin_sub(u32 x)
  87{
  88        return x ^ rol32(x, 2) ^ rol32(x, 10) ^ rol32(x, 18) ^ rol32(x, 24);
  89}
  90
  91static u32 sm4_key_sub(u32 x)
  92{
  93        return sm4_key_lin_sub(sm4_t_non_lin_sub(x));
  94}
  95
  96static u32 sm4_enc_sub(u32 x)
  97{
  98        return sm4_enc_lin_sub(sm4_t_non_lin_sub(x));
  99}
 100
 101static u32 sm4_round(const u32 *x, const u32 rk)
 102{
 103        return x[0] ^ sm4_enc_sub(x[1] ^ x[2] ^ x[3] ^ rk);
 104}
 105
 106
 107/**
 108 * crypto_sm4_expand_key - Expands the SM4 key as described in GB/T 32907-2016
 109 * @ctx:        The location where the computed key will be stored.
 110 * @in_key:     The supplied key.
 111 * @key_len:    The length of the supplied key.
 112 *
 113 * Returns 0 on success. The function fails only if an invalid key size (or
 114 * pointer) is supplied.
 115 */
 116int crypto_sm4_expand_key(struct crypto_sm4_ctx *ctx, const u8 *in_key,
 117                          unsigned int key_len)
 118{
 119        u32 rk[4], t;
 120        const u32 *key = (u32 *)in_key;
 121        int i;
 122
 123        if (key_len != SM4_KEY_SIZE)
 124                return -EINVAL;
 125
 126        for (i = 0; i < 4; ++i)
 127                rk[i] = get_unaligned_be32(&key[i]) ^ fk[i];
 128
 129        for (i = 0; i < 32; ++i) {
 130                t = rk[0] ^ sm4_key_sub(rk[1] ^ rk[2] ^ rk[3] ^ ck[i]);
 131                ctx->rkey_enc[i] = t;
 132                rk[0] = rk[1];
 133                rk[1] = rk[2];
 134                rk[2] = rk[3];
 135                rk[3] = t;
 136        }
 137
 138        for (i = 0; i < 32; ++i)
 139                ctx->rkey_dec[i] = ctx->rkey_enc[31 - i];
 140
 141        return 0;
 142}
 143EXPORT_SYMBOL_GPL(crypto_sm4_expand_key);
 144
 145/**
 146 * crypto_sm4_set_key - Set the SM4 key.
 147 * @tfm:        The %crypto_tfm that is used in the context.
 148 * @in_key:     The input key.
 149 * @key_len:    The size of the key.
 150 *
 151 * This function uses crypto_sm4_expand_key() to expand the key.
 152 * &crypto_sm4_ctx _must_ be the private data embedded in @tfm which is
 153 * retrieved with crypto_tfm_ctx().
 154 *
 155 * Return: 0 on success; -EINVAL on failure (only happens for bad key lengths)
 156 */
 157int crypto_sm4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 158                       unsigned int key_len)
 159{
 160        struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
 161
 162        return crypto_sm4_expand_key(ctx, in_key, key_len);
 163}
 164EXPORT_SYMBOL_GPL(crypto_sm4_set_key);
 165
 166static void sm4_do_crypt(const u32 *rk, u32 *out, const u32 *in)
 167{
 168        u32 x[4], i, t;
 169
 170        for (i = 0; i < 4; ++i)
 171                x[i] = get_unaligned_be32(&in[i]);
 172
 173        for (i = 0; i < 32; ++i) {
 174                t = sm4_round(x, rk[i]);
 175                x[0] = x[1];
 176                x[1] = x[2];
 177                x[2] = x[3];
 178                x[3] = t;
 179        }
 180
 181        for (i = 0; i < 4; ++i)
 182                put_unaligned_be32(x[3 - i], &out[i]);
 183}
 184
 185/* encrypt a block of text */
 186
 187void crypto_sm4_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 188{
 189        const struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
 190
 191        sm4_do_crypt(ctx->rkey_enc, (u32 *)out, (u32 *)in);
 192}
 193EXPORT_SYMBOL_GPL(crypto_sm4_encrypt);
 194
 195/* decrypt a block of text */
 196
 197void crypto_sm4_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 198{
 199        const struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
 200
 201        sm4_do_crypt(ctx->rkey_dec, (u32 *)out, (u32 *)in);
 202}
 203EXPORT_SYMBOL_GPL(crypto_sm4_decrypt);
 204
 205static struct crypto_alg sm4_alg = {
 206        .cra_name               =       "sm4",
 207        .cra_driver_name        =       "sm4-generic",
 208        .cra_priority           =       100,
 209        .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 210        .cra_blocksize          =       SM4_BLOCK_SIZE,
 211        .cra_ctxsize            =       sizeof(struct crypto_sm4_ctx),
 212        .cra_module             =       THIS_MODULE,
 213        .cra_u                  =       {
 214                .cipher = {
 215                        .cia_min_keysize        =       SM4_KEY_SIZE,
 216                        .cia_max_keysize        =       SM4_KEY_SIZE,
 217                        .cia_setkey             =       crypto_sm4_set_key,
 218                        .cia_encrypt            =       crypto_sm4_encrypt,
 219                        .cia_decrypt            =       crypto_sm4_decrypt
 220                }
 221        }
 222};
 223
 224static int __init sm4_init(void)
 225{
 226        return crypto_register_alg(&sm4_alg);
 227}
 228
 229static void __exit sm4_fini(void)
 230{
 231        crypto_unregister_alg(&sm4_alg);
 232}
 233
 234subsys_initcall(sm4_init);
 235module_exit(sm4_fini);
 236
 237MODULE_DESCRIPTION("SM4 Cipher Algorithm");
 238MODULE_LICENSE("GPL v2");
 239MODULE_ALIAS_CRYPTO("sm4");
 240MODULE_ALIAS_CRYPTO("sm4-generic");
 241
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