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(void *ctx_arg, const u8 *in_key, 49 unsigned int key_len, u32 *flags) 50 { 51 struct tea_ctx *ctx = ctx_arg; 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(void *ctx_arg, u8 *dst, const u8 *src) 70 { 71 u32 y, z, n, sum = 0; 72 u32 k0, k1, k2, k3; 73 74 struct tea_ctx *ctx = ctx_arg; 75 const __le32 *in = (const __le32 *)src; 76 __le32 *out = (__le32 *)dst; 77 78 y = le32_to_cpu(in[0]); 79 z = le32_to_cpu(in[1]); 80 81 k0 = ctx->KEY[0]; 82 k1 = ctx->KEY[1]; 83 k2 = ctx->KEY[2]; 84 k3 = ctx->KEY[3]; 85 86 n = TEA_ROUNDS; 87 88 while (n-- > 0) { 89 sum += TEA_DELTA; 90 y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); 91 z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); 92 } 93 94 out[0] = cpu_to_le32(y); 95 out[1] = cpu_to_le32(z); 96 } 97 98 static void tea_decrypt(void *ctx_arg, u8 *dst, const u8 *src) 99 { 100 u32 y, z, n, sum; 101 u32 k0, k1, k2, k3; 102 struct tea_ctx *ctx = ctx_arg; 103 const __le32 *in = (const __le32 *)src; 104 __le32 *out = (__le32 *)dst; 105 106 y = le32_to_cpu(in[0]); 107 z = le32_to_cpu(in[1]); 108 109 k0 = ctx->KEY[0]; 110 k1 = ctx->KEY[1]; 111 k2 = ctx->KEY[2]; 112 k3 = ctx->KEY[3]; 113 114 sum = TEA_DELTA << 5; 115 116 n = TEA_ROUNDS; 117 118 while (n-- > 0) { 119 z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); 120 y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); 121 sum -= TEA_DELTA; 122 } 123 124 out[0] = cpu_to_le32(y); 125 out[1] = cpu_to_le32(z); 126 } 127 128 static int xtea_setkey(void *ctx_arg, const u8 *in_key, 129 unsigned int key_len, u32 *flags) 130 { 131 struct xtea_ctx *ctx = ctx_arg; 132 const __le32 *key = (const __le32 *)in_key; 133 134 if (key_len != 16) 135 { 136 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 137 return -EINVAL; 138 } 139 140 ctx->KEY[0] = le32_to_cpu(key[0]); 141 ctx->KEY[1] = le32_to_cpu(key[1]); 142 ctx->KEY[2] = le32_to_cpu(key[2]); 143 ctx->KEY[3] = le32_to_cpu(key[3]); 144 145 return 0; 146 147 } 148 149 static void xtea_encrypt(void *ctx_arg, u8 *dst, const u8 *src) 150 { 151 u32 y, z, sum = 0; 152 u32 limit = XTEA_DELTA * XTEA_ROUNDS; 153 154 struct xtea_ctx *ctx = ctx_arg; 155 const __le32 *in = (const __le32 *)src; 156 __le32 *out = (__le32 *)dst; 157 158 y = le32_to_cpu(in[0]); 159 z = le32_to_cpu(in[1]); 160 161 while (sum != limit) { 162 y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]); 163 sum += XTEA_DELTA; 164 z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]); 165 } 166 167 out[0] = cpu_to_le32(y); 168 out[1] = cpu_to_le32(z); 169 } 170 171 static void xtea_decrypt(void *ctx_arg, u8 *dst, const u8 *src) 172 { 173 u32 y, z, sum; 174 struct tea_ctx *ctx = ctx_arg; 175 const __le32 *in = (const __le32 *)src; 176 __le32 *out = (__le32 *)dst; 177 178 y = le32_to_cpu(in[0]); 179 z = le32_to_cpu(in[1]); 180 181 sum = XTEA_DELTA * XTEA_ROUNDS; 182 183 while (sum) { 184 z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]); 185 sum -= XTEA_DELTA; 186 y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]); 187 } 188 189 out[0] = cpu_to_le32(y); 190 out[1] = cpu_to_le32(z); 191 } 192 193 194 static void xeta_encrypt(void *ctx_arg, u8 *dst, const u8 *src) 195 { 196 u32 y, z, sum = 0; 197 u32 limit = XTEA_DELTA * XTEA_ROUNDS; 198 199 struct xtea_ctx *ctx = ctx_arg; 200 const __le32 *in = (const __le32 *)src; 201 __le32 *out = (__le32 *)dst; 202 203 y = le32_to_cpu(in[0]); 204 z = le32_to_cpu(in[1]); 205 206 while (sum != limit) { 207 y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3]; 208 sum += XTEA_DELTA; 209 z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3]; 210 } 211 212 out[0] = cpu_to_le32(y); 213 out[1] = cpu_to_le32(z); 214 } 215 216 static void xeta_decrypt(void *ctx_arg, u8 *dst, const u8 *src) 217 { 218 u32 y, z, sum; 219 struct tea_ctx *ctx = ctx_arg; 220 const __le32 *in = (const __le32 *)src; 221 __le32 *out = (__le32 *)dst; 222 223 y = le32_to_cpu(in[0]); 224 z = le32_to_cpu(in[1]); 225 226 sum = XTEA_DELTA * XTEA_ROUNDS; 227 228 while (sum) { 229 z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3]; 230 sum -= XTEA_DELTA; 231 y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3]; 232 } 233 234 out[0] = cpu_to_le32(y); 235 out[1] = cpu_to_le32(z); 236 } 237 238 static struct crypto_alg tea_alg = { 239 .cra_name = "tea", 240 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 241 .cra_blocksize = TEA_BLOCK_SIZE, 242 .cra_ctxsize = sizeof (struct tea_ctx), 243 .cra_module = THIS_MODULE, 244 .cra_list = LIST_HEAD_INIT(tea_alg.cra_list), 245 .cra_u = { .cipher = { 246 .cia_min_keysize = TEA_KEY_SIZE, 247 .cia_max_keysize = TEA_KEY_SIZE, 248 .cia_setkey = tea_setkey, 249 .cia_encrypt = tea_encrypt, 250 .cia_decrypt = tea_decrypt } } 251 }; 252 253 static struct crypto_alg xtea_alg = { 254 .cra_name = "xtea", 255 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 256 .cra_blocksize = XTEA_BLOCK_SIZE, 257 .cra_ctxsize = sizeof (struct xtea_ctx), 258 .cra_module = THIS_MODULE, 259 .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list), 260 .cra_u = { .cipher = { 261 .cia_min_keysize = XTEA_KEY_SIZE, 262 .cia_max_keysize = XTEA_KEY_SIZE, 263 .cia_setkey = xtea_setkey, 264 .cia_encrypt = xtea_encrypt, 265 .cia_decrypt = xtea_decrypt } } 266 }; 267 268 static struct crypto_alg xeta_alg = { 269 .cra_name = "xeta", 270 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 271 .cra_blocksize = XTEA_BLOCK_SIZE, 272 .cra_ctxsize = sizeof (struct xtea_ctx), 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