1 | // SPDX-License-Identifier: GPL-2.0 |
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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 | module_init(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"); |

247 |