| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | /* |
| 3 | * Cryptographic API. |
| 4 | * |
| 5 | * TEA, XTEA, and XETA crypto alogrithms |
| 6 | * |
| 7 | * The TEA and Xtended TEA algorithms were developed by David Wheeler |
| 8 | * and Roger Needham at the Computer Laboratory of Cambridge University. |
| 9 | * |
| 10 | * Due to the order of evaluation in XTEA many people have incorrectly |
| 11 | * implemented it. XETA (XTEA in the wrong order), exists for |
| 12 | * compatibility with these implementations. |
| 13 | * |
| 14 | * Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com |
| 15 | */ |
| 16 | |
| 17 | #include <crypto/algapi.h> |
| 18 | #include <linux/init.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <asm/byteorder.h> |
| 22 | #include <linux/types.h> |
| 23 | |
| 24 | #define TEA_KEY_SIZE 16 |
| 25 | #define TEA_BLOCK_SIZE 8 |
| 26 | #define TEA_ROUNDS 32 |
| 27 | #define TEA_DELTA 0x9e3779b9 |
| 28 | |
| 29 | #define XTEA_KEY_SIZE 16 |
| 30 | #define XTEA_BLOCK_SIZE 8 |
| 31 | #define XTEA_ROUNDS 32 |
| 32 | #define XTEA_DELTA 0x9e3779b9 |
| 33 | |
| 34 | struct tea_ctx { |
| 35 | u32 KEY[4]; |
| 36 | }; |
| 37 | |
| 38 | struct xtea_ctx { |
| 39 | u32 KEY[4]; |
| 40 | }; |
| 41 | |
| 42 | static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key, |
| 43 | unsigned int key_len) |
| 44 | { |
| 45 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); |
| 46 | const __le32 *key = (const __le32 *)in_key; |
| 47 | |
| 48 | ctx->KEY[0] = le32_to_cpu(key[0]); |
| 49 | ctx->KEY[1] = le32_to_cpu(key[1]); |
| 50 | ctx->KEY[2] = le32_to_cpu(key[2]); |
| 51 | ctx->KEY[3] = le32_to_cpu(key[3]); |
| 52 | |
| 53 | return 0; |
| 54 | |
| 55 | } |
| 56 | |
| 57 | static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) |
| 58 | { |
| 59 | u32 y, z, n, sum = 0; |
| 60 | u32 k0, k1, k2, k3; |
| 61 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); |
| 62 | const __le32 *in = (const __le32 *)src; |
| 63 | __le32 *out = (__le32 *)dst; |
| 64 | |
| 65 | y = le32_to_cpu(in[0]); |
| 66 | z = le32_to_cpu(in[1]); |
| 67 | |
| 68 | k0 = ctx->KEY[0]; |
| 69 | k1 = ctx->KEY[1]; |
| 70 | k2 = ctx->KEY[2]; |
| 71 | k3 = ctx->KEY[3]; |
| 72 | |
| 73 | n = TEA_ROUNDS; |
| 74 | |
| 75 | while (n-- > 0) { |
| 76 | sum += TEA_DELTA; |
| 77 | y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); |
| 78 | z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); |
| 79 | } |
| 80 | |
| 81 | out[0] = cpu_to_le32(y); |
| 82 | out[1] = cpu_to_le32(z); |
| 83 | } |
| 84 | |
| 85 | static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) |
| 86 | { |
| 87 | u32 y, z, n, sum; |
| 88 | u32 k0, k1, k2, k3; |
| 89 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); |
| 90 | const __le32 *in = (const __le32 *)src; |
| 91 | __le32 *out = (__le32 *)dst; |
| 92 | |
| 93 | y = le32_to_cpu(in[0]); |
| 94 | z = le32_to_cpu(in[1]); |
| 95 | |
| 96 | k0 = ctx->KEY[0]; |
| 97 | k1 = ctx->KEY[1]; |
| 98 | k2 = ctx->KEY[2]; |
| 99 | k3 = ctx->KEY[3]; |
| 100 | |
| 101 | sum = TEA_DELTA << 5; |
| 102 | |
| 103 | n = TEA_ROUNDS; |
| 104 | |
| 105 | while (n-- > 0) { |
| 106 | z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); |
| 107 | y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); |
| 108 | sum -= TEA_DELTA; |
| 109 | } |
| 110 | |
| 111 | out[0] = cpu_to_le32(y); |
| 112 | out[1] = cpu_to_le32(z); |
| 113 | } |
| 114 | |
| 115 | static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key, |
| 116 | unsigned int key_len) |
| 117 | { |
| 118 | struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); |
| 119 | const __le32 *key = (const __le32 *)in_key; |
| 120 | |
| 121 | ctx->KEY[0] = le32_to_cpu(key[0]); |
| 122 | ctx->KEY[1] = le32_to_cpu(key[1]); |
| 123 | ctx->KEY[2] = le32_to_cpu(key[2]); |
| 124 | ctx->KEY[3] = le32_to_cpu(key[3]); |
| 125 | |
| 126 | return 0; |
| 127 | |
| 128 | } |
| 129 | |
| 130 | static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) |
| 131 | { |
| 132 | u32 y, z, sum = 0; |
| 133 | u32 limit = XTEA_DELTA * XTEA_ROUNDS; |
| 134 | struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); |
| 135 | const __le32 *in = (const __le32 *)src; |
| 136 | __le32 *out = (__le32 *)dst; |
| 137 | |
| 138 | y = le32_to_cpu(in[0]); |
| 139 | z = le32_to_cpu(in[1]); |
| 140 | |
| 141 | while (sum != limit) { |
| 142 | y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]); |
| 143 | sum += XTEA_DELTA; |
| 144 | z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]); |
| 145 | } |
| 146 | |
| 147 | out[0] = cpu_to_le32(y); |
| 148 | out[1] = cpu_to_le32(z); |
| 149 | } |
| 150 | |
| 151 | static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) |
| 152 | { |
| 153 | u32 y, z, sum; |
| 154 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); |
| 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 | sum = XTEA_DELTA * XTEA_ROUNDS; |
| 162 | |
| 163 | while (sum) { |
| 164 | z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]); |
| 165 | sum -= XTEA_DELTA; |
| 166 | y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]); |
| 167 | } |
| 168 | |
| 169 | out[0] = cpu_to_le32(y); |
| 170 | out[1] = cpu_to_le32(z); |
| 171 | } |
| 172 | |
| 173 | |
| 174 | static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) |
| 175 | { |
| 176 | u32 y, z, sum = 0; |
| 177 | u32 limit = XTEA_DELTA * XTEA_ROUNDS; |
| 178 | struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); |
| 179 | const __le32 *in = (const __le32 *)src; |
| 180 | __le32 *out = (__le32 *)dst; |
| 181 | |
| 182 | y = le32_to_cpu(in[0]); |
| 183 | z = le32_to_cpu(in[1]); |
| 184 | |
| 185 | while (sum != limit) { |
| 186 | y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3]; |
| 187 | sum += XTEA_DELTA; |
| 188 | z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3]; |
| 189 | } |
| 190 | |
| 191 | out[0] = cpu_to_le32(y); |
| 192 | out[1] = cpu_to_le32(z); |
| 193 | } |
| 194 | |
| 195 | static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) |
| 196 | { |
| 197 | u32 y, z, sum; |
| 198 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); |
| 199 | const __le32 *in = (const __le32 *)src; |
| 200 | __le32 *out = (__le32 *)dst; |
| 201 | |
| 202 | y = le32_to_cpu(in[0]); |
| 203 | z = le32_to_cpu(in[1]); |
| 204 | |
| 205 | sum = XTEA_DELTA * XTEA_ROUNDS; |
| 206 | |
| 207 | while (sum) { |
| 208 | z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3]; |
| 209 | sum -= XTEA_DELTA; |
| 210 | y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3]; |
| 211 | } |
| 212 | |
| 213 | out[0] = cpu_to_le32(y); |
| 214 | out[1] = cpu_to_le32(z); |
| 215 | } |
| 216 | |
| 217 | static struct crypto_alg tea_algs[3] = { { |
| 218 | .cra_name = "tea", |
| 219 | .cra_driver_name = "tea-generic", |
| 220 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, |
| 221 | .cra_blocksize = TEA_BLOCK_SIZE, |
| 222 | .cra_ctxsize = sizeof (struct tea_ctx), |
| 223 | .cra_alignmask = 3, |
| 224 | .cra_module = THIS_MODULE, |
| 225 | .cra_u = { .cipher = { |
| 226 | .cia_min_keysize = TEA_KEY_SIZE, |
| 227 | .cia_max_keysize = TEA_KEY_SIZE, |
| 228 | .cia_setkey = tea_setkey, |
| 229 | .cia_encrypt = tea_encrypt, |
| 230 | .cia_decrypt = tea_decrypt } } |
| 231 | }, { |
| 232 | .cra_name = "xtea", |
| 233 | .cra_driver_name = "xtea-generic", |
| 234 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, |
| 235 | .cra_blocksize = XTEA_BLOCK_SIZE, |
| 236 | .cra_ctxsize = sizeof (struct xtea_ctx), |
| 237 | .cra_alignmask = 3, |
| 238 | .cra_module = THIS_MODULE, |
| 239 | .cra_u = { .cipher = { |
| 240 | .cia_min_keysize = XTEA_KEY_SIZE, |
| 241 | .cia_max_keysize = XTEA_KEY_SIZE, |
| 242 | .cia_setkey = xtea_setkey, |
| 243 | .cia_encrypt = xtea_encrypt, |
| 244 | .cia_decrypt = xtea_decrypt } } |
| 245 | }, { |
| 246 | .cra_name = "xeta", |
| 247 | .cra_driver_name = "xeta-generic", |
| 248 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, |
| 249 | .cra_blocksize = XTEA_BLOCK_SIZE, |
| 250 | .cra_ctxsize = sizeof (struct xtea_ctx), |
| 251 | .cra_alignmask = 3, |
| 252 | .cra_module = THIS_MODULE, |
| 253 | .cra_u = { .cipher = { |
| 254 | .cia_min_keysize = XTEA_KEY_SIZE, |
| 255 | .cia_max_keysize = XTEA_KEY_SIZE, |
| 256 | .cia_setkey = xtea_setkey, |
| 257 | .cia_encrypt = xeta_encrypt, |
| 258 | .cia_decrypt = xeta_decrypt } } |
| 259 | } }; |
| 260 | |
| 261 | static int __init tea_mod_init(void) |
| 262 | { |
| 263 | return crypto_register_algs(tea_algs, ARRAY_SIZE(tea_algs)); |
| 264 | } |
| 265 | |
| 266 | static void __exit tea_mod_fini(void) |
| 267 | { |
| 268 | crypto_unregister_algs(tea_algs, ARRAY_SIZE(tea_algs)); |
| 269 | } |
| 270 | |
| 271 | MODULE_ALIAS_CRYPTO("tea"); |
| 272 | MODULE_ALIAS_CRYPTO("xtea"); |
| 273 | MODULE_ALIAS_CRYPTO("xeta"); |
| 274 | |
| 275 | subsys_initcall(tea_mod_init); |
| 276 | module_exit(tea_mod_fini); |
| 277 | |
| 278 | MODULE_LICENSE("GPL"); |
| 279 | MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms"); |