1/* 2 * Cryptographic API. 3 * 4 * AES Cipher Algorithm. 5 * 6 * Based on Brian Gladman's code. 7 * 8 * Linux developers: 9 * Alexander Kjeldaas <astor@fast.no> 10 * Herbert Valerio Riedel <hvr@hvrlab.org> 11 * Kyle McMartin <kyle@debian.org> 12 * Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API). 13 * 14 * This program is free software; you can redistribute it and/or modify 15 * it under the terms of the GNU General Public License as published by 16 * the Free Software Foundation; either version 2 of the License, or 17 * (at your option) any later version. 18 * 19 * --------------------------------------------------------------------------- 20 * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK. 21 * All rights reserved. 22 * 23 * LICENSE TERMS 24 * 25 * The free distribution and use of this software in both source and binary 26 * form is allowed (with or without changes) provided that: 27 * 28 * 1. distributions of this source code include the above copyright 29 * notice, this list of conditions and the following disclaimer; 30 * 31 * 2. distributions in binary form include the above copyright 32 * notice, this list of conditions and the following disclaimer 33 * in the documentation and/or other associated materials; 34 * 35 * 3. the copyright holder's name is not used to endorse products 36 * built using this software without specific written permission. 37 * 38 * ALTERNATIVELY, provided that this notice is retained in full, this product 39 * may be distributed under the terms of the GNU General Public License (GPL), 40 * in which case the provisions of the GPL apply INSTEAD OF those given above. 41 * 42 * DISCLAIMER 43 * 44 * This software is provided 'as is' with no explicit or implied warranties 45 * in respect of its properties, including, but not limited to, correctness 46 * and/or fitness for purpose. 47 * --------------------------------------------------------------------------- 48 */ 49 50/* Some changes from the Gladman version: 51 s/RIJNDAEL(e_key)/E_KEY/g 52 s/RIJNDAEL(d_key)/D_KEY/g 53*/ 54 55#include <linux/module.h> 56#include <linux/init.h> 57#include <linux/types.h> 58#include <linux/errno.h> 59//#include <linux/crypto.h> 60#include "rtl_crypto.h" 61#include <asm/byteorder.h> 62 63#define AES_MIN_KEY_SIZE 16 64#define AES_MAX_KEY_SIZE 32 65 66#define AES_BLOCK_SIZE 16 67 68static inline 69u32 generic_rotr32 (const u32 x, const unsigned bits) 70{ 71 const unsigned n = bits % 32; 72 return (x >> n) | (x << (32 - n)); 73} 74 75static inline 76u32 generic_rotl32 (const u32 x, const unsigned bits) 77{ 78 const unsigned n = bits % 32; 79 return (x << n) | (x >> (32 - n)); 80} 81 82#define rotl generic_rotl32 83#define rotr generic_rotr32 84 85/* 86 * #define byte(x, nr) ((unsigned char)((x) >> (nr*8))) 87 */ 88inline static u8 89byte(const u32 x, const unsigned n) 90{ 91 return x >> (n << 3); 92} 93 94#define u32_in(x) le32_to_cpu(*(const u32 *)(x)) 95#define u32_out(to, from) (*(u32 *)(to) = cpu_to_le32(from)) 96 97struct aes_ctx { 98 int key_length; 99 u32 E[60]; 100 u32 D[60]; 101}; 102 103#define E_KEY ctx->E 104#define D_KEY ctx->D 105 106static u8 pow_tab[256] __initdata; 107static u8 log_tab[256] __initdata; 108static u8 sbx_tab[256] __initdata; 109static u8 isb_tab[256] __initdata; 110static u32 rco_tab[10]; 111static u32 ft_tab[4][256]; 112static u32 it_tab[4][256]; 113 114static u32 fl_tab[4][256]; 115static u32 il_tab[4][256]; 116 117static inline u8 __init 118f_mult (u8 a, u8 b) 119{ 120 u8 aa = log_tab[a], cc = aa + log_tab[b]; 121 122 return pow_tab[cc + (cc < aa ? 1 : 0)]; 123} 124 125#define ff_mult(a,b) (a && b ? f_mult(a, b) : 0) 126 127#define f_rn(bo, bi, n, k) \ 128 bo[n] = ft_tab[0][byte(bi[n],0)] ^ \ 129 ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ 130 ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 131 ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) 132 133#define i_rn(bo, bi, n, k) \ 134 bo[n] = it_tab[0][byte(bi[n],0)] ^ \ 135 it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ 136 it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 137 it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 138 139#define ls_box(x) \ 140 ( fl_tab[0][byte(x, 0)] ^ \ 141 fl_tab[1][byte(x, 1)] ^ \ 142 fl_tab[2][byte(x, 2)] ^ \ 143 fl_tab[3][byte(x, 3)] ) 144 145#define f_rl(bo, bi, n, k) \ 146 bo[n] = fl_tab[0][byte(bi[n],0)] ^ \ 147 fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ 148 fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 149 fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) 150 151#define i_rl(bo, bi, n, k) \ 152 bo[n] = il_tab[0][byte(bi[n],0)] ^ \ 153 il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ 154 il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 155 il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 156 157static void __init 158gen_tabs (void) 159{ 160 u32 i, t; 161 u8 p, q; 162 163 /* log and power tables for GF(2**8) finite field with 164 0x011b as modular polynomial - the simplest primitive 165 root is 0x03, used here to generate the tables */ 166 167 for (i = 0, p = 1; i < 256; ++i) { 168 pow_tab[i] = (u8) p; 169 log_tab[p] = (u8) i; 170 171 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); 172 } 173 174 log_tab[1] = 0; 175 176 for (i = 0, p = 1; i < 10; ++i) { 177 rco_tab[i] = p; 178 179 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); 180 } 181 182 for (i = 0; i < 256; ++i) { 183 p = (i ? pow_tab[255 - log_tab[i]] : 0); 184 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); 185 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); 186 sbx_tab[i] = p; 187 isb_tab[p] = (u8) i; 188 } 189 190 for (i = 0; i < 256; ++i) { 191 p = sbx_tab[i]; 192 193 t = p; 194 fl_tab[0][i] = t; 195 fl_tab[1][i] = rotl (t, 8); 196 fl_tab[2][i] = rotl (t, 16); 197 fl_tab[3][i] = rotl (t, 24); 198 199 t = ((u32) ff_mult (2, p)) | 200 ((u32) p << 8) | 201 ((u32) p << 16) | ((u32) ff_mult (3, p) << 24); 202 203 ft_tab[0][i] = t; 204 ft_tab[1][i] = rotl (t, 8); 205 ft_tab[2][i] = rotl (t, 16); 206 ft_tab[3][i] = rotl (t, 24); 207 208 p = isb_tab[i]; 209 210 t = p; 211 il_tab[0][i] = t; 212 il_tab[1][i] = rotl (t, 8); 213 il_tab[2][i] = rotl (t, 16); 214 il_tab[3][i] = rotl (t, 24); 215 216 t = ((u32) ff_mult (14, p)) | 217 ((u32) ff_mult (9, p) << 8) | 218 ((u32) ff_mult (13, p) << 16) | 219 ((u32) ff_mult (11, p) << 24); 220 221 it_tab[0][i] = t; 222 it_tab[1][i] = rotl (t, 8); 223 it_tab[2][i] = rotl (t, 16); 224 it_tab[3][i] = rotl (t, 24); 225 } 226} 227 228#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) 229 230#define imix_col(y,x) \ 231 u = star_x(x); \ 232 v = star_x(u); \ 233 w = star_x(v); \ 234 t = w ^ (x); \ 235 (y) = u ^ v ^ w; \ 236 (y) ^= rotr(u ^ t, 8) ^ \ 237 rotr(v ^ t, 16) ^ \ 238 rotr(t,24) 239 240/* initialise the key schedule from the user supplied key */ 241 242#define loop4(i) \ 243{ t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \ 244 t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \ 245 t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \ 246 t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \ 247 t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \ 248} 249 250#define loop6(i) \ 251{ t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \ 252 t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \ 253 t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \ 254 t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \ 255 t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \ 256 t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \ 257 t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \ 258} 259 260#define loop8(i) \ 261{ t = rotr(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \ 262 t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \ 263 t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \ 264 t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \ 265 t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \ 266 t = E_KEY[8 * i + 4] ^ ls_box(t); \ 267 E_KEY[8 * i + 12] = t; \ 268 t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \ 269 t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \ 270 t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \ 271} 272 273static int 274aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags) 275{ 276 struct aes_ctx *ctx = ctx_arg; 277 u32 i, t, u, v, w; 278 279 if (key_len != 16 && key_len != 24 && key_len != 32) { 280 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 281 return -EINVAL; 282 } 283 284 ctx->key_length = key_len; 285 286 E_KEY[0] = u32_in (in_key); 287 E_KEY[1] = u32_in (in_key + 4); 288 E_KEY[2] = u32_in (in_key + 8); 289 E_KEY[3] = u32_in (in_key + 12); 290 291 switch (key_len) { 292 case 16: 293 t = E_KEY[3]; 294 for (i = 0; i < 10; ++i) 295 loop4 (i); 296 break; 297 298 case 24: 299 E_KEY[4] = u32_in (in_key + 16); 300 t = E_KEY[5] = u32_in (in_key + 20); 301 for (i = 0; i < 8; ++i) 302 loop6 (i); 303 break; 304 305 case 32: 306 E_KEY[4] = u32_in (in_key + 16); 307 E_KEY[5] = u32_in (in_key + 20); 308 E_KEY[6] = u32_in (in_key + 24); 309 t = E_KEY[7] = u32_in (in_key + 28); 310 for (i = 0; i < 7; ++i) 311 loop8 (i); 312 break; 313 } 314 315 D_KEY[0] = E_KEY[0]; 316 D_KEY[1] = E_KEY[1]; 317 D_KEY[2] = E_KEY[2]; 318 D_KEY[3] = E_KEY[3]; 319 320 for (i = 4; i < key_len + 24; ++i) { 321 imix_col (D_KEY[i], E_KEY[i]); 322 } 323 324 return 0; 325} 326 327/* encrypt a block of text */ 328 329#define f_nround(bo, bi, k) \ 330 f_rn(bo, bi, 0, k); \ 331 f_rn(bo, bi, 1, k); \ 332 f_rn(bo, bi, 2, k); \ 333 f_rn(bo, bi, 3, k); \ 334 k += 4 335 336#define f_lround(bo, bi, k) \ 337 f_rl(bo, bi, 0, k); \ 338 f_rl(bo, bi, 1, k); \ 339 f_rl(bo, bi, 2, k); \ 340 f_rl(bo, bi, 3, k) 341 342static void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in) 343{ 344 const struct aes_ctx *ctx = ctx_arg; 345 u32 b0[4], b1[4]; 346 const u32 *kp = E_KEY + 4; 347 348 b0[0] = u32_in (in) ^ E_KEY[0]; 349 b0[1] = u32_in (in + 4) ^ E_KEY[1]; 350 b0[2] = u32_in (in + 8) ^ E_KEY[2]; 351 b0[3] = u32_in (in + 12) ^ E_KEY[3]; 352 353 if (ctx->key_length > 24) { 354 f_nround (b1, b0, kp); 355 f_nround (b0, b1, kp); 356 } 357 358 if (ctx->key_length > 16) { 359 f_nround (b1, b0, kp); 360 f_nround (b0, b1, kp); 361 } 362 363 f_nround (b1, b0, kp); 364 f_nround (b0, b1, kp); 365 f_nround (b1, b0, kp); 366 f_nround (b0, b1, kp); 367 f_nround (b1, b0, kp); 368 f_nround (b0, b1, kp); 369 f_nround (b1, b0, kp); 370 f_nround (b0, b1, kp); 371 f_nround (b1, b0, kp); 372 f_lround (b0, b1, kp); 373 374 u32_out (out, b0[0]); 375 u32_out (out + 4, b0[1]); 376 u32_out (out + 8, b0[2]); 377 u32_out (out + 12, b0[3]); 378} 379 380/* decrypt a block of text */ 381 382#define i_nround(bo, bi, k) \ 383 i_rn(bo, bi, 0, k); \ 384 i_rn(bo, bi, 1, k); \ 385 i_rn(bo, bi, 2, k); \ 386 i_rn(bo, bi, 3, k); \ 387 k -= 4 388 389#define i_lround(bo, bi, k) \ 390 i_rl(bo, bi, 0, k); \ 391 i_rl(bo, bi, 1, k); \ 392 i_rl(bo, bi, 2, k); \ 393 i_rl(bo, bi, 3, k) 394 395static void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in) 396{ 397 const struct aes_ctx *ctx = ctx_arg; 398 u32 b0[4], b1[4]; 399 const int key_len = ctx->key_length; 400 const u32 *kp = D_KEY + key_len + 20; 401 402 b0[0] = u32_in (in) ^ E_KEY[key_len + 24]; 403 b0[1] = u32_in (in + 4) ^ E_KEY[key_len + 25]; 404 b0[2] = u32_in (in + 8) ^ E_KEY[key_len + 26]; 405 b0[3] = u32_in (in + 12) ^ E_KEY[key_len + 27]; 406 407 if (key_len > 24) { 408 i_nround (b1, b0, kp); 409 i_nround (b0, b1, kp); 410 } 411 412 if (key_len > 16) { 413 i_nround (b1, b0, kp); 414 i_nround (b0, b1, kp); 415 } 416 417 i_nround (b1, b0, kp); 418 i_nround (b0, b1, kp); 419 i_nround (b1, b0, kp); 420 i_nround (b0, b1, kp); 421 i_nround (b1, b0, kp); 422 i_nround (b0, b1, kp); 423 i_nround (b1, b0, kp); 424 i_nround (b0, b1, kp); 425 i_nround (b1, b0, kp); 426 i_lround (b0, b1, kp); 427 428 u32_out (out, b0[0]); 429 u32_out (out + 4, b0[1]); 430 u32_out (out + 8, b0[2]); 431 u32_out (out + 12, b0[3]); 432} 433 434 435static struct crypto_alg aes_alg = { 436 .cra_name = "aes", 437 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 438 .cra_blocksize = AES_BLOCK_SIZE, 439 .cra_ctxsize = sizeof(struct aes_ctx), 440 .cra_module = THIS_MODULE, 441 .cra_list = LIST_HEAD_INIT(aes_alg.cra_list), 442 .cra_u = { 443 .cipher = { 444 .cia_min_keysize = AES_MIN_KEY_SIZE, 445 .cia_max_keysize = AES_MAX_KEY_SIZE, 446 .cia_setkey = aes_set_key, 447 .cia_encrypt = aes_encrypt, 448 .cia_decrypt = aes_decrypt 449 } 450 } 451}; 452 453static int __init aes_init(void) 454{ 455 gen_tabs(); 456 return crypto_register_alg(&aes_alg); 457} 458 459static void __exit aes_fini(void) 460{ 461 crypto_unregister_alg(&aes_alg); 462} 463 464module_init(aes_init); 465module_exit(aes_fini); 466 467MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm"); 468MODULE_LICENSE("Dual BSD/GPL"); 469 470