drivers/staging/rtl8192u/ieee80211/aes.c

   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
  68 static inline
  69 u32 generic_rotr32 (const u32 x, const unsigned bits)
  70 {
  71         const unsigned n = bits % 32;
  72         return (x >> n) | (x << (32 - n));
  73 }
  74
  75 static inline
  76 u32 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  */
  88 inline static u8
  89 byte(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
  97 struct 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
 106 static u8 pow_tab[256] __initdata;
 107 static u8 log_tab[256] __initdata;
 108 static u8 sbx_tab[256] __initdata;
 109 static u8 isb_tab[256] __initdata;
 110 static u32 rco_tab[10];
 111 static u32 ft_tab[4][256];
 112 static u32 it_tab[4][256];
 113
 114 static u32 fl_tab[4][256];
 115 static u32 il_tab[4][256];
 116
 117 static inline u8 __init
 118 f_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
 157 static void __init
 158 gen_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
 273 static int
 274 aes_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
 342 static 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
 395 static 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
 435 static 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
 453 static int __init aes_init(void)
 454 {
 455         gen_tabs();
 456         return crypto_register_alg(&aes_alg);
 457 }
 458
 459 static void __exit aes_fini(void)
 460 {
 461         crypto_unregister_alg(&aes_alg);
 462 }
 463
 464 module_init(aes_init);
 465 module_exit(aes_fini);
 466
 467 MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
 468 MODULE_LICENSE("Dual BSD/GPL");
 469