crypto/sm4_generic.c

   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
  19 static const u32 fk[4] = {
  20         0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
  21 };
  22
  23 static 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
  58 static 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
  69 static 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
  80 static u32 sm4_key_lin_sub(u32 x)
  81 {
  82         return x ^ rol32(x, 13) ^ rol32(x, 23);
  83
  84 }
  85
  86 static 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
  91 static u32 sm4_key_sub(u32 x)
  92 {
  93         return sm4_key_lin_sub(sm4_t_non_lin_sub(x));
  94 }
  95
  96 static u32 sm4_enc_sub(u32 x)
  97 {
  98         return sm4_enc_lin_sub(sm4_t_non_lin_sub(x));
  99 }
 100
 101 static 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  */
 116 int 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 }
 143 EXPORT_SYMBOL_GPL(crypto_sm4_expand_key);
 144
 145 /**
 146  * crypto_sm4_set_key - Set the AES 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  * Returns 0 on success, on failure the %CRYPTO_TFM_RES_BAD_KEY_LEN flag in tfm
 152  * is set. The function uses crypto_sm4_expand_key() to expand the key.
 153  * &crypto_sm4_ctx _must_ be the private data embedded in @tfm which is
 154  * retrieved with crypto_tfm_ctx().
 155  */
 156 int crypto_sm4_set_key(struct crypto_tfm *tfm, const u8 *in_key,
 157                        unsigned int key_len)
 158 {
 159         struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
 160         u32 *flags = &tfm->crt_flags;
 161         int ret;
 162
 163         ret = crypto_sm4_expand_key(ctx, in_key, key_len);
 164         if (!ret)
 165                 return 0;
 166
 167         *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 168         return -EINVAL;
 169 }
 170 EXPORT_SYMBOL_GPL(crypto_sm4_set_key);
 171
 172 static void sm4_do_crypt(const u32 *rk, u32 *out, const u32 *in)
 173 {
 174         u32 x[4], i, t;
 175
 176         for (i = 0; i < 4; ++i)
 177                 x[i] = get_unaligned_be32(&in[i]);
 178
 179         for (i = 0; i < 32; ++i) {
 180                 t = sm4_round(x, rk[i]);
 181                 x[0] = x[1];
 182                 x[1] = x[2];
 183                 x[2] = x[3];
 184                 x[3] = t;
 185         }
 186
 187         for (i = 0; i < 4; ++i)
 188                 put_unaligned_be32(x[3 - i], &out[i]);
 189 }
 190
 191 /* encrypt a block of text */
 192
 193 void crypto_sm4_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 194 {
 195         const struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
 196
 197         sm4_do_crypt(ctx->rkey_enc, (u32 *)out, (u32 *)in);
 198 }
 199 EXPORT_SYMBOL_GPL(crypto_sm4_encrypt);
 200
 201 /* decrypt a block of text */
 202
 203 void crypto_sm4_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
 204 {
 205         const struct crypto_sm4_ctx *ctx = crypto_tfm_ctx(tfm);
 206
 207         sm4_do_crypt(ctx->rkey_dec, (u32 *)out, (u32 *)in);
 208 }
 209 EXPORT_SYMBOL_GPL(crypto_sm4_decrypt);
 210
 211 static struct crypto_alg sm4_alg = {
 212         .cra_name               =       "sm4",
 213         .cra_driver_name        =       "sm4-generic",
 214         .cra_priority           =       100,
 215         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 216         .cra_blocksize          =       SM4_BLOCK_SIZE,
 217         .cra_ctxsize            =       sizeof(struct crypto_sm4_ctx),
 218         .cra_module             =       THIS_MODULE,
 219         .cra_u                  =       {
 220                 .cipher = {
 221                         .cia_min_keysize        =       SM4_KEY_SIZE,
 222                         .cia_max_keysize        =       SM4_KEY_SIZE,
 223                         .cia_setkey             =       crypto_sm4_set_key,
 224                         .cia_encrypt            =       crypto_sm4_encrypt,
 225                         .cia_decrypt            =       crypto_sm4_decrypt
 226                 }
 227         }
 228 };
 229
 230 static int __init sm4_init(void)
 231 {
 232         return crypto_register_alg(&sm4_alg);
 233 }
 234
 235 static void __exit sm4_fini(void)
 236 {
 237         crypto_unregister_alg(&sm4_alg);
 238 }
 239
 240 subsys_initcall(sm4_init);
 241 module_exit(sm4_fini);
 242
 243 MODULE_DESCRIPTION("SM4 Cipher Algorithm");
 244 MODULE_LICENSE("GPL v2");
 245 MODULE_ALIAS_CRYPTO("sm4");
 246 MODULE_ALIAS_CRYPTO("sm4-generic");