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 E_KEY ctx->E 103 #define D_KEY ctx->D 104 105 static uint8_t pow_tab[256]; 106 static uint8_t log_tab[256]; 107 static uint8_t sbx_tab[256]; 108 static uint8_t isb_tab[256]; 109 static uint32_t rco_tab[10]; 110 static uint32_t ft_tab[4][256]; 111 static uint32_t it_tab[4][256]; 112 113 static uint32_t fl_tab[4][256]; 114 static uint32_t il_tab[4][256]; 115 116 static inline uint8_t 117 f_mult (uint8_t a, uint8_t b) 118 { 119 uint8_t aa = log_tab[a], cc = aa + log_tab[b]; 120 121 return pow_tab[cc + (cc < aa ? 1 : 0)]; 122 } 123 124 #define ff_mult(a,b) (a && b ? f_mult(a, b) : 0) 125 126 #define f_rn(bo, bi, n, k) \ 127 bo[n] = ft_tab[0][byte(bi[n],0)] ^ \ 128 ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ 129 ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 130 ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) 131 132 #define i_rn(bo, bi, n, k) \ 133 bo[n] = it_tab[0][byte(bi[n],0)] ^ \ 134 it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ 135 it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 136 it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 137 138 #define ls_box(x) \ 139 ( fl_tab[0][byte(x, 0)] ^ \ 140 fl_tab[1][byte(x, 1)] ^ \ 141 fl_tab[2][byte(x, 2)] ^ \ 142 fl_tab[3][byte(x, 3)] ) 143 144 #define f_rl(bo, bi, n, k) \ 145 bo[n] = fl_tab[0][byte(bi[n],0)] ^ \ 146 fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ 147 fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 148 fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) 149 150 #define i_rl(bo, bi, n, k) \ 151 bo[n] = il_tab[0][byte(bi[n],0)] ^ \ 152 il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ 153 il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ 154 il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) 155 156 static void 157 gen_tabs (void) 158 { 159 uint32_t i, t; 160 uint8_t p, q; 161 162 /* log and power tables for GF(2**8) finite field with 163 0x011b as modular polynomial - the simplest prmitive 164 root is 0x03, used here to generate the tables */ 165 166 for (i = 0, p = 1; i < 256; ++i) { 167 pow_tab[i] = (uint8_t) p; 168 log_tab[p] = (uint8_t) i; 169 170 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); 171 } 172 173 log_tab[1] = 0; 174 175 for (i = 0, p = 1; i < 10; ++i) { 176 rco_tab[i] = p; 177 178 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); 179 } 180 181 for (i = 0; i < 256; ++i) { 182 p = (i ? pow_tab[255 - log_tab[i]] : 0); 183 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); 184 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); 185 sbx_tab[i] = p; 186 isb_tab[p] = (uint8_t) i; 187 } 188 189 for (i = 0; i < 256; ++i) { 190 p = sbx_tab[i]; 191 192 t = p; 193 fl_tab[0][i] = t; 194 fl_tab[1][i] = rotl (t, 8); 195 fl_tab[2][i] = rotl (t, 16); 196 fl_tab[3][i] = rotl (t, 24); 197 198 t = ((uint32_t) ff_mult (2, p)) | 199 ((uint32_t) p << 8) | 200 ((uint32_t) p << 16) | ((uint32_t) ff_mult (3, p) << 24); 201 202 ft_tab[0][i] = t; 203 ft_tab[1][i] = rotl (t, 8); 204 ft_tab[2][i] = rotl (t, 16); 205 ft_tab[3][i] = rotl (t, 24); 206 207 p = isb_tab[i]; 208 209 t = p; 210 il_tab[0][i] = t; 211 il_tab[1][i] = rotl (t, 8); 212 il_tab[2][i] = rotl (t, 16); 213 il_tab[3][i] = rotl (t, 24); 214 215 t = ((uint32_t) ff_mult (14, p)) | 216 ((uint32_t) ff_mult (9, p) << 8) | 217 ((uint32_t) ff_mult (13, p) << 16) | 218 ((uint32_t) ff_mult (11, p) << 24); 219 220 it_tab[0][i] = t; 221 it_tab[1][i] = rotl (t, 8); 222 it_tab[2][i] = rotl (t, 16); 223 it_tab[3][i] = rotl (t, 24); 224 } 225 } 226 227 #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) 228 229 #define imix_col(y,x) \ 230 u = star_x(x); \ 231 v = star_x(u); \ 232 w = star_x(v); \ 233 t = w ^ (x); \ 234 (y) = u ^ v ^ w; \ 235 (y) ^= rotr(u ^ t, 8) ^ \ 236 rotr(v ^ t, 16) ^ \ 237 rotr(t,24) 238 239 /* initialise the key schedule from the user supplied key */ 240 241 #define loop4(i) \ 242 { t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \ 243 t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \ 244 t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \ 245 t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \ 246 t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \ 247 } 248 249 #define loop6(i) \ 250 { t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \ 251 t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \ 252 t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \ 253 t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \ 254 t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \ 255 t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \ 256 t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \ 257 } 258 259 #define loop8(i) \ 260 { t = rotr(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \ 261 t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \ 262 t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \ 263 t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \ 264 t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \ 265 t = E_KEY[8 * i + 4] ^ ls_box(t); \ 266 E_KEY[8 * i + 12] = t; \ 267 t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \ 268 t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \ 269 t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \ 270 } 271 272 /* Tells whether the ACE is capable to generate 273 the extended key for a given key_len. */ 274 static inline int 275 aes_hw_extkey_available(uint8_t key_len) 276 { 277 /* TODO: We should check the actual CPU model/stepping 278 as it's possible that the capability will be 279 added in the next CPU revisions. */ 280 if (key_len == 16) 281 return 1; 282 return 0; 283 } 284 285 static inline struct aes_ctx *aes_ctx(void *ctx) 286 { 287 unsigned long align = PADLOCK_ALIGNMENT; 288 289 if (align <= crypto_tfm_ctx_alignment()) 290 align = 1; 291 return (struct aes_ctx *)ALIGN((unsigned long)ctx, align); 292 } 293 294 static int 295 aes_set_key(void *ctx_arg, const uint8_t *in_key, unsigned int key_len, uint32_t *flags) 296 { 297 struct aes_ctx *ctx = aes_ctx(ctx_arg); 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->E = ctx->e_data; 316 ctx->D = ctx->e_data; 317 318 E_KEY[0] = le32_to_cpu(key[0]); 319 E_KEY[1] = le32_to_cpu(key[1]); 320 E_KEY[2] = le32_to_cpu(key[2]); 321 E_KEY[3] = le32_to_cpu(key[3]); 322 323 /* Prepare control words. */ 324 memset(&ctx->cword, 0, sizeof(ctx->cword)); 325 326 ctx->cword.decrypt.encdec = 1; 327 ctx->cword.encrypt.rounds = 10 + (key_len - 16) / 4; 328 ctx->cword.decrypt.rounds = ctx->cword.encrypt.rounds; 329 ctx->cword.encrypt.ksize = (key_len - 16) / 8; 330 ctx->cword.decrypt.ksize = ctx->cword.encrypt.ksize; 331 332 /* Don't generate extended keys if the hardware can do it. */ 333 if (aes_hw_extkey_available(key_len)) 334 return 0; 335 336 ctx->D = ctx->d_data; 337 ctx->cword.encrypt.keygen = 1; 338 ctx->cword.decrypt.keygen = 1; 339 340 switch (key_len) { 341 case 16: 342 t = E_KEY[3]; 343 for (i = 0; i < 10; ++i) 344 loop4 (i); 345 break; 346 347 case 24: 348 E_KEY[4] = le32_to_cpu(key[4]); 349 t = E_KEY[5] = le32_to_cpu(key[5]); 350 for (i = 0; i < 8; ++i) 351 loop6 (i); 352 break; 353 354 case 32: 355 E_KEY[4] = le32_to_cpu(key[4]); 356 E_KEY[5] = le32_to_cpu(key[5]); 357 E_KEY[6] = le32_to_cpu(key[6]); 358 t = E_KEY[7] = le32_to_cpu(key[7]); 359 for (i = 0; i < 7; ++i) 360 loop8 (i); 361 break; 362 } 363 364 D_KEY[0] = E_KEY[0]; 365 D_KEY[1] = E_KEY[1]; 366 D_KEY[2] = E_KEY[2]; 367 D_KEY[3] = E_KEY[3]; 368 369 for (i = 4; i < key_len + 24; ++i) { 370 imix_col (D_KEY[i], E_KEY[i]); 371 } 372 373 /* PadLock needs a different format of the decryption key. */ 374 rounds = 10 + (key_len - 16) / 4; 375 376 for (i = 0; i < rounds; i++) { 377 P[((i + 1) * 4) + 0] = D_KEY[((rounds - i - 1) * 4) + 0]; 378 P[((i + 1) * 4) + 1] = D_KEY[((rounds - i - 1) * 4) + 1]; 379 P[((i + 1) * 4) + 2] = D_KEY[((rounds - i - 1) * 4) + 2]; 380 P[((i + 1) * 4) + 3] = D_KEY[((rounds - i - 1) * 4) + 3]; 381 } 382 383 P[0] = E_KEY[(rounds * 4) + 0]; 384 P[1] = E_KEY[(rounds * 4) + 1]; 385 P[2] = E_KEY[(rounds * 4) + 2]; 386 P[3] = E_KEY[(rounds * 4) + 3]; 387 388 memcpy(D_KEY, P, AES_EXTENDED_KEY_SIZE_B); 389 390 return 0; 391 } 392 393 /* ====== Encryption/decryption routines ====== */ 394 395 /* These are the real call to PadLock. */ 396 static inline void padlock_xcrypt_ecb(const u8 *input, u8 *output, void *key, 397 void *control_word, u32 count) 398 { 399 asm volatile ("pushfl; popfl"); /* enforce key reload. */ 400 asm volatile (".byte 0xf3,0x0f,0xa7,0xc8" /* rep xcryptecb */ 401 : "+S"(input), "+D"(output) 402 : "d"(control_word), "b"(key), "c"(count)); 403 } 404 405 static inline u8 *padlock_xcrypt_cbc(const u8 *input, u8 *output, void *key, 406 u8 *iv, void *control_word, u32 count) 407 { 408 /* Enforce key reload. */ 409 asm volatile ("pushfl; popfl"); 410 /* rep xcryptcbc */ 411 asm volatile (".byte 0xf3,0x0f,0xa7,0xd0" 412 : "+S" (input), "+D" (output), "+a" (iv) 413 : "d" (control_word), "b" (key), "c" (count)); 414 return iv; 415 } 416 417 static void 418 aes_encrypt(void *ctx_arg, uint8_t *out, const uint8_t *in) 419 { 420 struct aes_ctx *ctx = aes_ctx(ctx_arg); 421 padlock_xcrypt_ecb(in, out, ctx->E, &ctx->cword.encrypt, 1); 422 } 423 424 static void 425 aes_decrypt(void *ctx_arg, uint8_t *out, const uint8_t *in) 426 { 427 struct aes_ctx *ctx = aes_ctx(ctx_arg); 428 padlock_xcrypt_ecb(in, out, ctx->D, &ctx->cword.decrypt, 1); 429 } 430 431 static unsigned int aes_encrypt_ecb(const struct cipher_desc *desc, u8 *out, 432 const u8 *in, unsigned int nbytes) 433 { 434 struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm)); 435 padlock_xcrypt_ecb(in, out, ctx->E, &ctx->cword.encrypt, 436 nbytes / AES_BLOCK_SIZE); 437 return nbytes & ~(AES_BLOCK_SIZE - 1); 438 } 439 440 static unsigned int aes_decrypt_ecb(const struct cipher_desc *desc, u8 *out, 441 const u8 *in, unsigned int nbytes) 442 { 443 struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm)); 444 padlock_xcrypt_ecb(in, out, ctx->D, &ctx->cword.decrypt, 445 nbytes / AES_BLOCK_SIZE); 446 return nbytes & ~(AES_BLOCK_SIZE - 1); 447 } 448 449 static unsigned int aes_encrypt_cbc(const struct cipher_desc *desc, u8 *out, 450 const u8 *in, unsigned int nbytes) 451 { 452 struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm)); 453 u8 *iv; 454 455 iv = padlock_xcrypt_cbc(in, out, ctx->E, desc->info, 456 &ctx->cword.encrypt, nbytes / AES_BLOCK_SIZE); 457 memcpy(desc->info, iv, AES_BLOCK_SIZE); 458 459 return nbytes & ~(AES_BLOCK_SIZE - 1); 460 } 461 462 static unsigned int aes_decrypt_cbc(const struct cipher_desc *desc, u8 *out, 463 const u8 *in, unsigned int nbytes) 464 { 465 struct aes_ctx *ctx = aes_ctx(crypto_tfm_ctx(desc->tfm)); 466 padlock_xcrypt_cbc(in, out, ctx->D, desc->info, &ctx->cword.decrypt, 467 nbytes / AES_BLOCK_SIZE); 468 return nbytes & ~(AES_BLOCK_SIZE - 1); 469 } 470 471 static struct crypto_alg aes_alg = { 472 .cra_name = "aes", 473 .cra_driver_name = "aes-padlock", 474 .cra_priority = 300, 475 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 476 .cra_blocksize = AES_BLOCK_SIZE, 477 .cra_ctxsize = sizeof(struct aes_ctx), 478 .cra_alignmask = PADLOCK_ALIGNMENT - 1, 479 .cra_module = THIS_MODULE, 480 .cra_list = LIST_HEAD_INIT(aes_alg.cra_list), 481 .cra_u = { 482 .cipher = { 483 .cia_min_keysize = AES_MIN_KEY_SIZE, 484 .cia_max_keysize = AES_MAX_KEY_SIZE, 485 .cia_setkey = aes_set_key, 486 .cia_encrypt = aes_encrypt, 487 .cia_decrypt = aes_decrypt, 488 .cia_encrypt_ecb = aes_encrypt_ecb, 489 .cia_decrypt_ecb = aes_decrypt_ecb, 490 .cia_encrypt_cbc = aes_encrypt_cbc, 491 .cia_decrypt_cbc = aes_decrypt_cbc, 492 } 493 } 494 }; 495 496 int __init padlock_init_aes(void) 497 { 498 printk(KERN_NOTICE PFX "Using VIA PadLock ACE for AES algorithm.\n"); 499 500 gen_tabs(); 501 return crypto_register_alg(&aes_alg); 502 } 503 504 void __exit padlock_fini_aes(void) 505 { 506 crypto_unregister_alg(&aes_alg); 507 } 508