1 /* 2 * Cryptographic API. 3 * 4 * TEA, XTEA, and XETA crypto alogrithms 5 * 6 * The TEA and Xtended TEA algorithms were developed by David Wheeler 7 * and Roger Needham at the Computer Laboratory of Cambridge University. 8 * 9 * Due to the order of evaluation in XTEA many people have incorrectly 10 * implemented it. XETA (XTEA in the wrong order), exists for 11 * compatibility with these implementations. 12 * 13 * Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com 14 * 15 * This program is free software; you can redistribute it and/or modify 16 * it under the terms of the GNU General Public License as published by 17 * the Free Software Foundation; either version 2 of the License, or 18 * (at your option) any later version. 19 * 20 */ 21 22 #include <linux/init.h> 23 #include <linux/module.h> 24 #include <linux/mm.h> 25 #include <asm/byteorder.h> 26 #include <asm/scatterlist.h> 27 #include <linux/crypto.h> 28 #include <linux/types.h> 29 30 #define TEA_KEY_SIZE 16 31 #define TEA_BLOCK_SIZE 8 32 #define TEA_ROUNDS 32 33 #define TEA_DELTA 0x9e3779b9 34 35 #define XTEA_KEY_SIZE 16 36 #define XTEA_BLOCK_SIZE 8 37 #define XTEA_ROUNDS 32 38 #define XTEA_DELTA 0x9e3779b9 39 40 struct tea_ctx { 41 u32 KEY[4]; 42 }; 43 44 struct xtea_ctx { 45 u32 KEY[4]; 46 }; 47 48 static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key, 49 unsigned int key_len, u32 *flags) 50 { 51 struct tea_ctx *ctx = crypto_tfm_ctx(tfm); 52 const __le32 *key = (const __le32 *)in_key; 53 54 if (key_len != 16) 55 { 56 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 57 return -EINVAL; 58 } 59 60 ctx->KEY[0] = le32_to_cpu(key[0]); 61 ctx->KEY[1] = le32_to_cpu(key[1]); 62 ctx->KEY[2] = le32_to_cpu(key[2]); 63 ctx->KEY[3] = le32_to_cpu(key[3]); 64 65 return 0; 66 67 } 68 69 static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) 70 { 71 u32 y, z, n, sum = 0; 72 u32 k0, k1, k2, k3; 73 struct tea_ctx *ctx = crypto_tfm_ctx(tfm); 74 const __le32 *in = (const __le32 *)src; 75 __le32 *out = (__le32 *)dst; 76 77 y = le32_to_cpu(in[0]); 78 z = le32_to_cpu(in[1]); 79 80 k0 = ctx->KEY[0]; 81 k1 = ctx->KEY[1]; 82 k2 = ctx->KEY[2]; 83 k3 = ctx->KEY[3]; 84 85 n = TEA_ROUNDS; 86 87 while (n-- > 0) { 88 sum += TEA_DELTA; 89 y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); 90 z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); 91 } 92 93 out[0] = cpu_to_le32(y); 94 out[1] = cpu_to_le32(z); 95 } 96 97 static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) 98 { 99 u32 y, z, n, sum; 100 u32 k0, k1, k2, k3; 101 struct tea_ctx *ctx = crypto_tfm_ctx(tfm); 102 const __le32 *in = (const __le32 *)src; 103 __le32 *out = (__le32 *)dst; 104 105 y = le32_to_cpu(in[0]); 106 z = le32_to_cpu(in[1]); 107 108 k0 = ctx->KEY[0]; 109 k1 = ctx->KEY[1]; 110 k2 = ctx->KEY[2]; 111 k3 = ctx->KEY[3]; 112 113 sum = TEA_DELTA << 5; 114 115 n = TEA_ROUNDS; 116 117 while (n-- > 0) { 118 z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); 119 y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); 120 sum -= TEA_DELTA; 121 } 122 123 out[0] = cpu_to_le32(y); 124 out[1] = cpu_to_le32(z); 125 } 126 127 static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key, 128 unsigned int key_len, u32 *flags) 129 { 130 struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); 131 const __le32 *key = (const __le32 *)in_key; 132 133 if (key_len != 16) 134 { 135 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 136 return -EINVAL; 137 } 138 139 ctx->KEY[0] = le32_to_cpu(key[0]); 140 ctx->KEY[1] = le32_to_cpu(key[1]); 141 ctx->KEY[2] = le32_to_cpu(key[2]); 142 ctx->KEY[3] = le32_to_cpu(key[3]); 143 144 return 0; 145 146 } 147 148 static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) 149 { 150 u32 y, z, sum = 0; 151 u32 limit = XTEA_DELTA * XTEA_ROUNDS; 152 struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); 153 const __le32 *in = (const __le32 *)src; 154 __le32 *out = (__le32 *)dst; 155 156 y = le32_to_cpu(in[0]); 157 z = le32_to_cpu(in[1]); 158 159 while (sum != limit) { 160 y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]); 161 sum += XTEA_DELTA; 162 z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]); 163 } 164 165 out[0] = cpu_to_le32(y); 166 out[1] = cpu_to_le32(z); 167 } 168 169 static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) 170 { 171 u32 y, z, sum; 172 struct tea_ctx *ctx = crypto_tfm_ctx(tfm); 173 const __le32 *in = (const __le32 *)src; 174 __le32 *out = (__le32 *)dst; 175 176 y = le32_to_cpu(in[0]); 177 z = le32_to_cpu(in[1]); 178 179 sum = XTEA_DELTA * XTEA_ROUNDS; 180 181 while (sum) { 182 z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]); 183 sum -= XTEA_DELTA; 184 y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]); 185 } 186 187 out[0] = cpu_to_le32(y); 188 out[1] = cpu_to_le32(z); 189 } 190 191 192 static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) 193 { 194 u32 y, z, sum = 0; 195 u32 limit = XTEA_DELTA * XTEA_ROUNDS; 196 struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); 197 const __le32 *in = (const __le32 *)src; 198 __le32 *out = (__le32 *)dst; 199 200 y = le32_to_cpu(in[0]); 201 z = le32_to_cpu(in[1]); 202 203 while (sum != limit) { 204 y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3]; 205 sum += XTEA_DELTA; 206 z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3]; 207 } 208 209 out[0] = cpu_to_le32(y); 210 out[1] = cpu_to_le32(z); 211 } 212 213 static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) 214 { 215 u32 y, z, sum; 216 struct tea_ctx *ctx = crypto_tfm_ctx(tfm); 217 const __le32 *in = (const __le32 *)src; 218 __le32 *out = (__le32 *)dst; 219 220 y = le32_to_cpu(in[0]); 221 z = le32_to_cpu(in[1]); 222 223 sum = XTEA_DELTA * XTEA_ROUNDS; 224 225 while (sum) { 226 z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3]; 227 sum -= XTEA_DELTA; 228 y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3]; 229 } 230 231 out[0] = cpu_to_le32(y); 232 out[1] = cpu_to_le32(z); 233 } 234 235 static struct crypto_alg tea_alg = { 236 .cra_name = "tea", 237 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 238 .cra_blocksize = TEA_BLOCK_SIZE, 239 .cra_ctxsize = sizeof (struct tea_ctx), 240 .cra_alignmask = 3, 241 .cra_module = THIS_MODULE, 242 .cra_list = LIST_HEAD_INIT(tea_alg.cra_list), 243 .cra_u = { .cipher = { 244 .cia_min_keysize = TEA_KEY_SIZE, 245 .cia_max_keysize = TEA_KEY_SIZE, 246 .cia_setkey = tea_setkey, 247 .cia_encrypt = tea_encrypt, 248 .cia_decrypt = tea_decrypt } } 249 }; 250 251 static struct crypto_alg xtea_alg = { 252 .cra_name = "xtea", 253 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 254 .cra_blocksize = XTEA_BLOCK_SIZE, 255 .cra_ctxsize = sizeof (struct xtea_ctx), 256 .cra_alignmask = 3, 257 .cra_module = THIS_MODULE, 258 .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list), 259 .cra_u = { .cipher = { 260 .cia_min_keysize = XTEA_KEY_SIZE, 261 .cia_max_keysize = XTEA_KEY_SIZE, 262 .cia_setkey = xtea_setkey, 263 .cia_encrypt = xtea_encrypt, 264 .cia_decrypt = xtea_decrypt } } 265 }; 266 267 static struct crypto_alg xeta_alg = { 268 .cra_name = "xeta", 269 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 270 .cra_blocksize = XTEA_BLOCK_SIZE, 271 .cra_ctxsize = sizeof (struct xtea_ctx), 272 .cra_alignmask = 3, 273 .cra_module = THIS_MODULE, 274 .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list), 275 .cra_u = { .cipher = { 276 .cia_min_keysize = XTEA_KEY_SIZE, 277 .cia_max_keysize = XTEA_KEY_SIZE, 278 .cia_setkey = xtea_setkey, 279 .cia_encrypt = xeta_encrypt, 280 .cia_decrypt = xeta_decrypt } } 281 }; 282 283 static int __init init(void) 284 { 285 int ret = 0; 286 287 ret = crypto_register_alg(&tea_alg); 288 if (ret < 0) 289 goto out; 290 291 ret = crypto_register_alg(&xtea_alg); 292 if (ret < 0) { 293 crypto_unregister_alg(&tea_alg); 294 goto out; 295 } 296 297 ret = crypto_register_alg(&xeta_alg); 298 if (ret < 0) { 299 crypto_unregister_alg(&tea_alg); 300 crypto_unregister_alg(&xtea_alg); 301 goto out; 302 } 303 304 out: 305 return ret; 306 } 307 308 static void __exit fini(void) 309 { 310 crypto_unregister_alg(&tea_alg); 311 crypto_unregister_alg(&xtea_alg); 312 crypto_unregister_alg(&xeta_alg); 313 } 314 315 MODULE_ALIAS("xtea"); 316 MODULE_ALIAS("xeta"); 317 318 module_init(init); 319 module_exit(fini); 320 321 MODULE_LICENSE("GPL"); 322 MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms"); 323