1 /* 2 * Cryptographic API. 3 * 4 * Support for VIA PadLock hardware crypto engine. 5 * 6 * Copyright (c) 2004 Michal Ludvig <michal@logix.cz> 7 * 8 * Key expansion routine taken from crypto/aes.c 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or 13 * (at your option) any later version. 14 * 15 * --------------------------------------------------------------------------- 16 * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK. 17 * All rights reserved. 18 * 19 * LICENSE TERMS 20 * 21 * The free distribution and use of this software in both source and binary 22 * form is allowed (with or without changes) provided that: 23 * 24 * 1. distributions of this source code include the above copyright 25 * notice, this list of conditions and the following disclaimer; 26 * 27 * 2. distributions in binary form include the above copyright 28 * notice, this list of conditions and the following disclaimer 29 * in the documentation and/or other associated materials; 30 * 31 * 3. the copyright holder's name is not used to endorse products 32 * built using this software without specific written permission. 33 * 34 * ALTERNATIVELY, provided that this notice is retained in full, this product 35 * may be distributed under the terms of the GNU General Public License (GPL), 36 * in which case the provisions of the GPL apply INSTEAD OF those given above. 37 * 38 * DISCLAIMER 39 * 40 * This software is provided 'as is' with no explicit or implied warranties 41 * in respect of its properties, including, but not limited to, correctness 42 * and/or fitness for purpose. 43 * --------------------------------------------------------------------------- 44 */ 45 46 #include <linux/module.h> 47 #include <linux/init.h> 48 #include <linux/types.h> 49 #include <linux/errno.h> 50 #include <linux/crypto.h> 51 #include <linux/interrupt.h> 52 #include <linux/kernel.h> 53 #include <asm/byteorder.h> 54 #include "padlock.h" 55 56 #define AES_MIN_KEY_SIZE 16 /* in uint8_t units */ 57 #define AES_MAX_KEY_SIZE 32 /* ditto */ 58 #define AES_BLOCK_SIZE 16 /* ditto */ 59 #define AES_EXTENDED_KEY_SIZE 64 /* in uint32_t units */ 60 #define AES_EXTENDED_KEY_SIZE_B (AES_EXTENDED_KEY_SIZE * sizeof(uint32_t)) 61 62 struct aes_ctx { 63 uint32_t e_data[AES_EXTENDED_KEY_SIZE]; 64 uint32_t d_data[AES_EXTENDED_KEY_SIZE]; 65 struct { 66 struct cword encrypt; 67 struct cword decrypt; 68 } cword; 69 uint32_t *E; 70 uint32_t *D; 71 int key_length; 72 }; 73 74 /* ====== Key management routines ====== */ 75 76 static inline uint32_t 77 generic_rotr32 (const uint32_t x, const unsigned bits) 78 { 79 const unsigned n = bits % 32; 80 return (x >> n) | (x << (32 - n)); 81 } 82 83 static inline uint32_t 84 generic_rotl32 (const uint32_t x, const unsigned bits) 85 { 86 const unsigned n = bits % 32; 87 return (x << n) | (x >> (32 - n)); 88 } 89 90 #define rotl generic_rotl32 91 #define rotr generic_rotr32 92 93 /* 94 * #define byte(x, nr) ((unsigned char)((x) >> (nr*8))) 95 */ 96 static inline uint8_t 97 byte(const uint32_t x, const unsigned n) 98 { 99 return x >> (n << 3); 100 } 101 102 #define uint32_t_in(x) le32_to_cpu(*(const uint32_t *)(x)) 103 #define uint32_t_out(to, from) (*(uint32_t *)(to) = cpu_to_le32(from)) 104 105 #define E_KEY ctx->E 106 #define D_KEY ctx->D 107 108 static uint8_t pow_tab[256]; 109 static uint8_t log_tab[256]; 110 static uint8_t sbx_tab[256]; 111 static uint8_t isb_tab[256]; 112 static uint32_t rco_tab[10]; 113 static uint32_t ft_tab[4][256]; 114 static uint32_t it_tab[4][256]; 115 116 static uint32_t fl_tab[4][256]; 117 static uint32_t il_tab[4][256]; 118 119 static inline uint8_t 120 f_mult (uint8_t a, uint8_t b) 121 { 122 uint8_t aa = log_tab[a], cc = aa + log_tab[b]; 123 124 return pow_tab[cc + (cc < aa ? 1 : 0)]; 125 } 126 127 #define ff_mult(a,b) (a && b ? f_mult(a, b) : 0) 128 129 #define f_rn(bo, bi, n, k) \ 130 bo[n] = ft_tab[0][byte(bi[n],0)] ^ \ 131 ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ 132 ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 133 ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) 134 135 #define i_rn(bo, bi, n, k) \ 136 bo[n] = it_tab[0][byte(bi[n],0)] ^ \ 137 it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ 138 it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 139 it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 140 141 #define ls_box(x) \ 142 ( fl_tab[0][byte(x, 0)] ^ \ 143 fl_tab[1][byte(x, 1)] ^ \ 144 fl_tab[2][byte(x, 2)] ^ \ 145 fl_tab[3][byte(x, 3)] ) 146 147 #define f_rl(bo, bi, n, k) \ 148 bo[n] = fl_tab[0][byte(bi[n],0)] ^ \ 149 fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ 150 fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 151 fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) 152 153 #define i_rl(bo, bi, n, k) \ 154 bo[n] = il_tab[0][byte(bi[n],0)] ^ \ 155 il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ 156 il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 157 il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 158 159 static void 160 gen_tabs (void) 161 { 162 uint32_t i, t; 163 uint8_t p, q; 164 165 /* log and power tables for GF(2**8) finite field with 166 0x011b as modular polynomial - the simplest prmitive 167 root is 0x03, used here to generate the tables */ 168 169 for (i = 0, p = 1; i < 256; ++i) { 170 pow_tab[i] = (uint8_t) p; 171 log_tab[p] = (uint8_t) i; 172 173 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); 174 } 175 176 log_tab[1] = 0; 177 178 for (i = 0, p = 1; i < 10; ++i) { 179 rco_tab[i] = p; 180 181 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); 182 } 183 184 for (i = 0; i < 256; ++i) { 185 p = (i ? pow_tab[255 - log_tab[i]] : 0); 186 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); 187 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); 188 sbx_tab[i] = p; 189 isb_tab[p] = (uint8_t) i; 190 } 191 192 for (i = 0; i < 256; ++i) { 193 p = sbx_tab[i]; 194 195 t = p; 196 fl_tab[0][i] = t; 197 fl_tab[1][i] = rotl (t, 8); 198 fl_tab[2][i] = rotl (t, 16); 199 fl_tab[3][i] = rotl (t, 24); 200 201 t = ((uint32_t) ff_mult (2, p)) | 202 ((uint32_t) p << 8) | 203 ((uint32_t) p << 16) | ((uint32_t) ff_mult (3, p) << 24); 204 205 ft_tab[0][i] = t; 206 ft_tab[1][i] = rotl (t, 8); 207 ft_tab[2][i] = rotl (t, 16); 208 ft_tab[3][i] = rotl (t, 24); 209 210 p = isb_tab[i]; 211 212 t = p; 213 il_tab[0][i] = t; 214 il_tab[1][i] = rotl (t, 8); 215 il_tab[2][i] = rotl (t, 16); 216 il_tab[3][i] = rotl (t, 24); 217 218 t = ((uint32_t) ff_mult (14, p)) | 219 ((uint32_t) ff_mult (9, p) << 8) | 220 ((uint32_t) ff_mult (13, p) << 16) | 221 ((uint32_t) ff_mult (11, p) << 24); 222 223 it_tab[0][i] = t; 224 it_tab[1][i] = rotl (t, 8); 225 it_tab[2][i] = rotl (t, 16); 226 it_tab[3][i] = rotl (t, 24); 227 } 228 } 229 230 #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) 231 232 #define imix_col(y,x) \ 233 u = star_x(x); \ 234 v = star_x(u); \ 235 w = star_x(v); \ 236 t = w ^ (x); \ 237 (y) = u ^ v ^ w; \ 238 (y) ^= rotr(u ^ t, 8) ^ \ 239 rotr(v ^ t, 16) ^ \ 240 rotr(t,24) 241 242 /* initialise the key schedule from the user supplied key */ 243 244 #define loop4(i) \ 245 { t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \ 246 t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \ 247 t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \ 248 t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \ 249 t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \ 250 } 251 252 #define loop6(i) \ 253 { t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \ 254 t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \ 255 t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \ 256 t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \ 257 t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \ 258 t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \ 259 t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \ 260 } 261 262 #define loop8(i) \ 263 { t = rotr(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \ 264 t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \ 265 t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \ 266 t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \ 267 t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \ 268 t = E_KEY[8 * i + 4] ^ ls_box(t); \ 269 E_KEY[8 * i + 12] = t; \ 270 t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \ 271 t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \ 272 t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \ 273 } 274 275 /* Tells whether the ACE is capable to generate 276 the extended key for a given key_len. */ 277 static inline int 278 aes_hw_extkey_available(uint8_t key_len) 279 { 280 /* TODO: We should check the actual CPU model/stepping 281 as it's possible that the capability will be 282 added in the next CPU revisions. */ 283 if (key_len == 16) 284 return 1; 285 return 0; 286 } 287 288 static inline struct aes_ctx *aes_ctx(void *ctx) 289 { 290 return (struct aes_ctx *)ALIGN((unsigned long)ctx, PADLOCK_ALIGNMENT); 291 } 292 293 static int 294 aes_set_key(void *ctx_arg, const uint8_t *in_key, unsigned int key_len, uint32_t *flags) 295 { 296 struct aes_ctx *ctx = aes_ctx(ctx_arg); 297 uint32_t i, t, u, v, w; 298 uint32_t P[AES_EXTENDED_KEY_SIZE]; 299 uint32_t rounds; 300 301 if (key_len != 16 && key_len != 24 && key_len != 32) { 302 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 303 return -EINVAL; 304 } 305 306 ctx->key_length = key_len; 307 308 /* 309 * If the hardware is capable of generating the extended key 310 * itself we must supply the plain key for both encryption 311 * and decryption. 312 */ 313 ctx->E = ctx->e_data; 314 ctx->D = ctx->e_data; 315 316 E_KEY[0] = uint32_t_in (in_key); 317 E_KEY[1] = uint32_t_in (in_key + 4); 318 E_KEY[2] = uint32_t_in (in_key + 8); 319 E_KEY[3] = uint32_t_in (in_key + 12); 320 321 /* Prepare control words. */ 322 memset(&ctx->cword, 0, sizeof(ctx->cword)); 323 324 ctx->cword.decrypt.encdec = 1; 325 ctx->cword.encrypt.rounds = 10 + (key_len - 16) / 4; 326 ctx->cword.decrypt.rounds = ctx->cword.encrypt.rounds; 327 ctx->cword.encrypt.ksize = (key_len - 16) / 8; 328 ctx->cword.decrypt.ksize = ctx->cword.encrypt.ksize; 329 330 /* Don't generate extended keys if the hardware can do it. */ 331 if (aes_hw_extkey_available(key_len)) 332 return 0; 333 334 ctx->D = ctx->d_data; 335 ctx->cword.encrypt.keygen = 1; 336 ctx->cword.decrypt.keygen = 1; 337 338 switch (key_len) { 339 case 16: 340 t = E_KEY[3]; 341 for (i = 0; i < 10; ++i) 342 loop4 (i); 343 break; 344 345 case 24: 346 E_KEY[4] = uint32_t_in (in_key + 16); 347 t = E_KEY[5] = uint32_t_in (in_key + 20); 348 for (i = 0; i < 8; ++i) 349 loop6 (i); 350 break; 351 352 case 32: 353 E_KEY[4] = uint32_t_in (in_key + 16); 354 E_KEY[5] = uint32_t_in (in_key + 20); 355 E_KEY[6] = uint32_t_in (in_key + 24); 356 t = E_KEY[7] = uint32_t_in (in_key + 28); 357 for (i = 0; i < 7; ++i) 358 loop8 (i); 359 break; 360 } 361 362 D_KEY[0] = E_KEY[0]; 363 D_KEY[1] = E_KEY[1]; 364 D_KEY[2] = E_KEY[2]; 365 D_KEY[3] = E_KEY[3]; 366 367 for (i = 4; i < key_len + 24; ++i) { 368 imix_col (D_KEY[i], E_KEY[i]); 369 } 370 371 /* PadLock needs a different format of the decryption key. */ 372 rounds = 10 + (key_len - 16) / 4; 373 374 for (i = 0; i < rounds; i++) { 375 P[((i + 1) * 4) + 0] = D_KEY[((rounds - i - 1) * 4) + 0]; 376 P[((i + 1) * 4) + 1] = D_KEY[((rounds - i - 1) * 4) + 1]; 377 P[((i + 1) * 4) + 2] = D_KEY[((rounds - i - 1) * 4) + 2]; 378 P[((i + 1) * 4) + 3] = D_KEY[((rounds - i - 1) * 4) + 3]; 379 } 380 381 P[0] = E_KEY[(rounds * 4) + 0]; 382 P[1] = E_KEY[(rounds * 4) + 1]; 383 P[2] = E_KEY[(rounds * 4) + 2]; 384 P[3] = E_KEY[(rounds * 4) + 3]; 385 386 memcpy(D_KEY, P, AES_EXTENDED_KEY_SIZE_B); 387 388 return 0; 389 } 390 391 /* ====== Encryption/decryption routines ====== */ 392 393 /* These are the real call to PadLock. */ 394 static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key, 395 void *control_word, u32 count) 396 { 397 asm volatile ("pushfl; popfl"); /* enforce key reload. */ 398 asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */ 399 : "+S"(input), "+D"(output) 400 : "d"(control_word), "b"(key), "c"(count)); 401 } 402 403 static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key, 404 u8 *iv, void *control_word, u32 count) 405 { 406 /* Enforce key reload. */ 407 asm volatile ("pushfl; popfl"); 408 /* rep xcryptcbc */ 409 asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" 410 : "+S" (input), "+D" (output), "+a" (iv) 411 : "d" (control_word), "b" (key), "c" (count)); 412 return iv; 413 } 414 415 static void 416 aes_encrypt(void *ctx_arg, uint8_t *out, const uint8_t *in) 417 { 418 struct aes_ctx *ctx = aes_ctx(ctx_arg); 419 padlock_xcrypt_ecb(in, out, ctx->E, &ctx->cword.encrypt, 1); 420 } 421 422 static void 423 aes_decrypt(void *ctx_arg, uint8_t *out, const uint8_t *in) 424 { 425 struct aes_ctx *ctx = aes_ctx(ctx_arg); 426 padlock_xcrypt_ecb(in, out, ctx->D, &ctx->cword.decrypt, 1); 427 } 428 429 static unsigned int aes_encrypt_ecb(const struct cipher_desc *desc, u8 *out, 430 const u8 *in, unsigned int nbytes) 431 { 432 struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm)); 433 padlock_xcrypt_ecb(in, out, ctx->E, &ctx->cword.encrypt, 434 nbytes / AES_BLOCK_SIZE); 435 return nbytes & ~(AES_BLOCK_SIZE - 1); 436 } 437 438 static unsigned int aes_decrypt_ecb(const struct cipher_desc *desc, u8 *out, 439 const u8 *in, unsigned int nbytes) 440 { 441 struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm)); 442 padlock_xcrypt_ecb(in, out, ctx->D, &ctx->cword.decrypt, 443 nbytes / AES_BLOCK_SIZE); 444 return nbytes & ~(AES_BLOCK_SIZE - 1); 445 } 446 447 static unsigned int aes_encrypt_cbc(const struct cipher_desc *desc, u8 *out, 448 const u8 *in, unsigned int nbytes) 449 { 450 struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm)); 451 u8 *iv; 452 453 iv = padlock_xcrypt_cbc(in, out, ctx->E, desc->info, 454 &ctx->cword.encrypt, nbytes / AES_BLOCK_SIZE); 455 memcpy(desc->info, iv, AES_BLOCK_SIZE); 456 457 return nbytes & ~(AES_BLOCK_SIZE - 1); 458 } 459 460 static unsigned int aes_decrypt_cbc(const struct cipher_desc *desc, u8 *out, 461 const u8 *in, unsigned int nbytes) 462 { 463 struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm)); 464 padlock_xcrypt_cbc(in, out, ctx->D, desc->info, &ctx->cword.decrypt, 465 nbytes / AES_BLOCK_SIZE); 466 return nbytes & ~(AES_BLOCK_SIZE - 1); 467 } 468 469 static struct crypto_alg aes_alg = { 470 .cra_name = "aes", 471 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 472 .cra_blocksize = AES_BLOCK_SIZE, 473 .cra_ctxsize = sizeof(struct aes_ctx), 474 .cra_alignmask = PADLOCK_ALIGNMENT - 1, 475 .cra_module = THIS_MODULE, 476 .cra_list = LIST_HEAD_INIT(aes_alg.cra_list), 477 .cra_u = { 478 .cipher = { 479 .cia_min_keysize = AES_MIN_KEY_SIZE, 480 .cia_max_keysize = AES_MAX_KEY_SIZE, 481 .cia_setkey = aes_set_key, 482 .cia_encrypt = aes_encrypt, 483 .cia_decrypt = aes_decrypt, 484 .cia_encrypt_ecb = aes_encrypt_ecb, 485 .cia_decrypt_ecb = aes_decrypt_ecb, 486 .cia_encrypt_cbc = aes_encrypt_cbc, 487 .cia_decrypt_cbc = aes_decrypt_cbc, 488 } 489 } 490 }; 491 492 int __init padlock_init_aes(void) 493 { 494 printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n"); 495 496 gen_tabs(); 497 return crypto_register_alg(&aes_alg); 498 } 499 500 void __exit padlock_fini_aes(void) 501 { 502 crypto_unregister_alg(&aes_alg); 503 } 504