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 struct { 64 struct cword encrypt; 65 struct cword decrypt; 66 } cword; 67 u32 *D; 68 int key_length; 69 u32 E[AES_EXTENDED_KEY_SIZE]; 70 u32 d_data[AES_EXTENDED_KEY_SIZE]; 71 }; 72 73 /* ====== Key management routines ====== */ 74 75 static inline uint32_t 76 generic_rotr32 (const uint32_t x, const unsigned bits) 77 { 78 const unsigned n = bits % 32; 79 return (x >> n) | (x << (32 - n)); 80 } 81 82 static inline uint32_t 83 generic_rotl32 (const uint32_t x, const unsigned bits) 84 { 85 const unsigned n = bits % 32; 86 return (x << n) | (x >> (32 - n)); 87 } 88 89 #define rotl generic_rotl32 90 #define rotr generic_rotr32 91 92 /* 93 * #define byte(x, nr) ((unsigned char)((x) >> (nr*8))) 94 */ 95 static inline uint8_t 96 byte(const uint32_t x, const unsigned n) 97 { 98 return x >> (n << 3); 99 } 100 101 #define E_KEY ctx->E 102 #define D_KEY ctx->D 103 104 static uint8_t pow_tab[256]; 105 static uint8_t log_tab[256]; 106 static uint8_t sbx_tab[256]; 107 static uint8_t isb_tab[256]; 108 static uint32_t rco_tab[10]; 109 static uint32_t ft_tab[4][256]; 110 static uint32_t it_tab[4][256]; 111 112 static uint32_t fl_tab[4][256]; 113 static uint32_t il_tab[4][256]; 114 115 static inline uint8_t 116 f_mult (uint8_t a, uint8_t b) 117 { 118 uint8_t aa = log_tab[a], cc = aa + log_tab[b]; 119 120 return pow_tab[cc + (cc < aa ? 1 : 0)]; 121 } 122 123 #define ff_mult(a,b) (a && b ? f_mult(a, b) : 0) 124 125 #define f_rn(bo, bi, n, k) \ 126 bo[n] = ft_tab[0][byte(bi[n],0)] ^ \ 127 ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ 128 ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 129 ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) 130 131 #define i_rn(bo, bi, n, k) \ 132 bo[n] = it_tab[0][byte(bi[n],0)] ^ \ 133 it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ 134 it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 135 it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 136 137 #define ls_box(x) \ 138 ( fl_tab[0][byte(x, 0)] ^ \ 139 fl_tab[1][byte(x, 1)] ^ \ 140 fl_tab[2][byte(x, 2)] ^ \ 141 fl_tab[3][byte(x, 3)] ) 142 143 #define f_rl(bo, bi, n, k) \ 144 bo[n] = fl_tab[0][byte(bi[n],0)] ^ \ 145 fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ 146 fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 147 fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) 148 149 #define i_rl(bo, bi, n, k) \ 150 bo[n] = il_tab[0][byte(bi[n],0)] ^ \ 151 il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ 152 il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 153 il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 154 155 static void 156 gen_tabs (void) 157 { 158 uint32_t i, t; 159 uint8_t p, q; 160 161 /* log and power tables for GF(2**8) finite field with 162 0x011b as modular polynomial - the simplest prmitive 163 root is 0x03, used here to generate the tables */ 164 165 for (i = 0, p = 1; i < 256; ++i) { 166 pow_tab[i] = (uint8_t) p; 167 log_tab[p] = (uint8_t) i; 168 169 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); 170 } 171 172 log_tab[1] = 0; 173 174 for (i = 0, p = 1; i < 10; ++i) { 175 rco_tab[i] = p; 176 177 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); 178 } 179 180 for (i = 0; i < 256; ++i) { 181 p = (i ? pow_tab[255 - log_tab[i]] : 0); 182 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); 183 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); 184 sbx_tab[i] = p; 185 isb_tab[p] = (uint8_t) i; 186 } 187 188 for (i = 0; i < 256; ++i) { 189 p = sbx_tab[i]; 190 191 t = p; 192 fl_tab[0][i] = t; 193 fl_tab[1][i] = rotl (t, 8); 194 fl_tab[2][i] = rotl (t, 16); 195 fl_tab[3][i] = rotl (t, 24); 196 197 t = ((uint32_t) ff_mult (2, p)) | 198 ((uint32_t) p << 8) | 199 ((uint32_t) p << 16) | ((uint32_t) ff_mult (3, p) << 24); 200 201 ft_tab[0][i] = t; 202 ft_tab[1][i] = rotl (t, 8); 203 ft_tab[2][i] = rotl (t, 16); 204 ft_tab[3][i] = rotl (t, 24); 205 206 p = isb_tab[i]; 207 208 t = p; 209 il_tab[0][i] = t; 210 il_tab[1][i] = rotl (t, 8); 211 il_tab[2][i] = rotl (t, 16); 212 il_tab[3][i] = rotl (t, 24); 213 214 t = ((uint32_t) ff_mult (14, p)) | 215 ((uint32_t) ff_mult (9, p) << 8) | 216 ((uint32_t) ff_mult (13, p) << 16) | 217 ((uint32_t) ff_mult (11, p) << 24); 218 219 it_tab[0][i] = t; 220 it_tab[1][i] = rotl (t, 8); 221 it_tab[2][i] = rotl (t, 16); 222 it_tab[3][i] = rotl (t, 24); 223 } 224 } 225 226 #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) 227 228 #define imix_col(y,x) \ 229 u = star_x(x); \ 230 v = star_x(u); \ 231 w = star_x(v); \ 232 t = w ^ (x); \ 233 (y) = u ^ v ^ w; \ 234 (y) ^= rotr(u ^ t, 8) ^ \ 235 rotr(v ^ t, 16) ^ \ 236 rotr(t,24) 237 238 /* initialise the key schedule from the user supplied key */ 239 240 #define loop4(i) \ 241 { t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \ 242 t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \ 243 t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \ 244 t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \ 245 t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \ 246 } 247 248 #define loop6(i) \ 249 { t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \ 250 t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \ 251 t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \ 252 t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \ 253 t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \ 254 t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \ 255 t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \ 256 } 257 258 #define loop8(i) \ 259 { t = rotr(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \ 260 t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \ 261 t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \ 262 t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \ 263 t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \ 264 t = E_KEY[8 * i + 4] ^ ls_box(t); \ 265 E_KEY[8 * i + 12] = t; \ 266 t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \ 267 t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \ 268 t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \ 269 } 270 271 /* Tells whether the ACE is capable to generate 272 the extended key for a given key_len. */ 273 static inline int 274 aes_hw_extkey_available(uint8_t key_len) 275 { 276 /* TODO: We should check the actual CPU model/stepping 277 as it's possible that the capability will be 278 added in the next CPU revisions. */ 279 if (key_len == 16) 280 return 1; 281 return 0; 282 } 283 284 static inline struct aes_ctx *aes_ctx(struct crypto_tfm *tfm) 285 { 286 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm); 287 unsigned long align = PADLOCK_ALIGNMENT; 288 289 if (align <= crypto_tfm_ctx_alignment()) 290 align = 1; 291 return (struct aes_ctx *)ALIGN(addr, align); 292 } 293 294 static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key, 295 unsigned int key_len, u32 *flags) 296 { 297 struct aes_ctx *ctx = aes_ctx(tfm); 298 const __le32 *key = (const __le32 *)in_key; 299 uint32_t i, t, u, v, w; 300 uint32_t P[AES_EXTENDED_KEY_SIZE]; 301 uint32_t rounds; 302 303 if (key_len != 16 && key_len != 24 && key_len != 32) { 304 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; 305 return -EINVAL; 306 } 307 308 ctx->key_length = key_len; 309 310 /* 311 * If the hardware is capable of generating the extended key 312 * itself we must supply the plain key for both encryption 313 * and decryption. 314 */ 315 ctx->D = ctx->E; 316 317 E_KEY[0] = le32_to_cpu(key[0]); 318 E_KEY[1] = le32_to_cpu(key[1]); 319 E_KEY[2] = le32_to_cpu(key[2]); 320 E_KEY[3] = le32_to_cpu(key[3]); 321 322 /* Prepare control words. */ 323 memset(&ctx->cword, 0, sizeof(ctx->cword)); 324 325 ctx->cword.decrypt.encdec = 1; 326 ctx->cword.encrypt.rounds = 10 + (key_len - 16) / 4; 327 ctx->cword.decrypt.rounds = ctx->cword.encrypt.rounds; 328 ctx->cword.encrypt.ksize = (key_len - 16) / 8; 329 ctx->cword.decrypt.ksize = ctx->cword.encrypt.ksize; 330 331 /* Don't generate extended keys if the hardware can do it. */ 332 if (aes_hw_extkey_available(key_len)) 333 return 0; 334 335 ctx->D = ctx->d_data; 336 ctx->cword.encrypt.keygen = 1; 337 ctx->cword.decrypt.keygen = 1; 338 339 switch (key_len) { 340 case 16: 341 t = E_KEY[3]; 342 for (i = 0; i < 10; ++i) 343 loop4 (i); 344 break; 345 346 case 24: 347 E_KEY[4] = le32_to_cpu(key[4]); 348 t = E_KEY[5] = le32_to_cpu(key[5]); 349 for (i = 0; i < 8; ++i) 350 loop6 (i); 351 break; 352 353 case 32: 354 E_KEY[4] = le32_to_cpu(key[4]); 355 E_KEY[5] = le32_to_cpu(key[5]); 356 E_KEY[6] = le32_to_cpu(key[6]); 357 t = E_KEY[7] = le32_to_cpu(key[7]); 358 for (i = 0; i < 7; ++i) 359 loop8 (i); 360 break; 361 } 362 363 D_KEY[0] = E_KEY[0]; 364 D_KEY[1] = E_KEY[1]; 365 D_KEY[2] = E_KEY[2]; 366 D_KEY[3] = E_KEY[3]; 367 368 for (i = 4; i < key_len + 24; ++i) { 369 imix_col (D_KEY[i], E_KEY[i]); 370 } 371 372 /* PadLock needs a different format of the decryption key. */ 373 rounds = 10 + (key_len - 16) / 4; 374 375 for (i = 0; i < rounds; i++) { 376 P[((i + 1) * 4) + 0] = D_KEY[((rounds - i - 1) * 4) + 0]; 377 P[((i + 1) * 4) + 1] = D_KEY[((rounds - i - 1) * 4) + 1]; 378 P[((i + 1) * 4) + 2] = D_KEY[((rounds - i - 1) * 4) + 2]; 379 P[((i + 1) * 4) + 3] = D_KEY[((rounds - i - 1) * 4) + 3]; 380 } 381 382 P[0] = E_KEY[(rounds * 4) + 0]; 383 P[1] = E_KEY[(rounds * 4) + 1]; 384 P[2] = E_KEY[(rounds * 4) + 2]; 385 P[3] = E_KEY[(rounds * 4) + 3]; 386 387 memcpy(D_KEY, P, AES_EXTENDED_KEY_SIZE_B); 388 389 return 0; 390 } 391 392 /* ====== Encryption/decryption routines ====== */ 393 394 /* These are the real call to PadLock. */ 395 static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key, 396 void *control_word, u32 count) 397 { 398 asm volatile ("pushfl; popfl"); /* enforce key reload. */ 399 asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */ 400 : "+S"(input), "+D"(output) 401 : "d"(control_word), "b"(key), "c"(count)); 402 } 403 404 static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key, 405 u8 *iv, void *control_word, u32 count) 406 { 407 /* Enforce key reload. */ 408 asm volatile ("pushfl; popfl"); 409 /* rep xcryptcbc */ 410 asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" 411 : "+S" (input), "+D" (output), "+a" (iv) 412 : "d" (control_word), "b" (key), "c" (count)); 413 return iv; 414 } 415 416 static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) 417 { 418 struct aes_ctx *ctx = aes_ctx(tfm); 419 padlock_xcrypt_ecb(in, out, ctx->E, &ctx->cword.encrypt, 1); 420 } 421 422 static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) 423 { 424 struct aes_ctx *ctx = aes_ctx(tfm); 425 padlock_xcrypt_ecb(in, out, ctx->D, &ctx->cword.decrypt, 1); 426 } 427 428 static unsigned int aes_encrypt_ecb(const struct cipher_desc *desc, u8 *out, 429 const u8 *in, unsigned int nbytes) 430 { 431 struct aes_ctx *ctx = aes_ctx(desc->tfm); 432 padlock_xcrypt_ecb(in, out, ctx->E, &ctx->cword.encrypt, 433 nbytes / AES_BLOCK_SIZE); 434 return nbytes & ~(AES_BLOCK_SIZE - 1); 435 } 436 437 static unsigned int aes_decrypt_ecb(const struct cipher_desc *desc, u8 *out, 438 const u8 *in, unsigned int nbytes) 439 { 440 struct aes_ctx *ctx = aes_ctx(desc->tfm); 441 padlock_xcrypt_ecb(in, out, ctx->D, &ctx->cword.decrypt, 442 nbytes / AES_BLOCK_SIZE); 443 return nbytes & ~(AES_BLOCK_SIZE - 1); 444 } 445 446 static unsigned int aes_encrypt_cbc(const struct cipher_desc *desc, u8 *out, 447 const u8 *in, unsigned int nbytes) 448 { 449 struct aes_ctx *ctx = aes_ctx(desc->tfm); 450 u8 *iv; 451 452 iv = padlock_xcrypt_cbc(in, out, ctx->E, desc->info, 453 &ctx->cword.encrypt, nbytes / AES_BLOCK_SIZE); 454 memcpy(desc->info, iv, AES_BLOCK_SIZE); 455 456 return nbytes & ~(AES_BLOCK_SIZE - 1); 457 } 458 459 static unsigned int aes_decrypt_cbc(const struct cipher_desc *desc, u8 *out, 460 const u8 *in, unsigned int nbytes) 461 { 462 struct aes_ctx *ctx = aes_ctx(desc->tfm); 463 padlock_xcrypt_cbc(in, out, ctx->D, desc->info, &ctx->cword.decrypt, 464 nbytes / AES_BLOCK_SIZE); 465 return nbytes & ~(AES_BLOCK_SIZE - 1); 466 } 467 468 static struct crypto_alg aes_alg = { 469 .cra_name = "aes", 470 .cra_driver_name = "aes-padlock", 471 .cra_priority = 300, 472 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 473 .cra_blocksize = AES_BLOCK_SIZE, 474 .cra_ctxsize = sizeof(struct aes_ctx), 475 .cra_alignmask = PADLOCK_ALIGNMENT - 1, 476 .cra_module = THIS_MODULE, 477 .cra_list = LIST_HEAD_INIT(aes_alg.cra_list), 478 .cra_u = { 479 .cipher = { 480 .cia_min_keysize = AES_MIN_KEY_SIZE, 481 .cia_max_keysize = AES_MAX_KEY_SIZE, 482 .cia_setkey = aes_set_key, 483 .cia_encrypt = aes_encrypt, 484 .cia_decrypt = aes_decrypt, 485 .cia_encrypt_ecb = aes_encrypt_ecb, 486 .cia_decrypt_ecb = aes_decrypt_ecb, 487 .cia_encrypt_cbc = aes_encrypt_cbc, 488 .cia_decrypt_cbc = aes_decrypt_cbc, 489 } 490 } 491 }; 492 493 int __init padlock_init_aes(void) 494 { 495 printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n"); 496 497 gen_tabs(); 498 return crypto_register_alg(&aes_alg); 499 } 500 501 void __exit padlock_fini_aes(void) 502 { 503 crypto_unregister_alg(&aes_alg); 504 } 505