qemu/crypto/cipher-builtin.c

   1 /*
   2  * QEMU Crypto cipher built-in algorithms
   3  *
   4  * Copyright (c) 2015 Red Hat, Inc.
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "crypto/aes.h"
  23 #include "crypto/desrfb.h"
  24 #include "crypto/xts.h"
  25
  26 typedef struct QCryptoCipherBuiltinAESContext QCryptoCipherBuiltinAESContext;
  27 struct QCryptoCipherBuiltinAESContext {
  28     AES_KEY enc;
  29     AES_KEY dec;
  30 };
  31 typedef struct QCryptoCipherBuiltinAES QCryptoCipherBuiltinAES;
  32 struct QCryptoCipherBuiltinAES {
  33     QCryptoCipherBuiltinAESContext key;
  34     QCryptoCipherBuiltinAESContext key_tweak;
  35     uint8_t iv[AES_BLOCK_SIZE];
  36 };
  37 typedef struct QCryptoCipherBuiltinDESRFB QCryptoCipherBuiltinDESRFB;
  38 struct QCryptoCipherBuiltinDESRFB {
  39     uint8_t *key;
  40     size_t nkey;
  41 };
  42
  43 typedef struct QCryptoCipherBuiltin QCryptoCipherBuiltin;
  44 struct QCryptoCipherBuiltin {
  45     union {
  46         QCryptoCipherBuiltinAES aes;
  47         QCryptoCipherBuiltinDESRFB desrfb;
  48     } state;
  49     size_t blocksize;
  50     void (*free)(QCryptoCipher *cipher);
  51     int (*setiv)(QCryptoCipher *cipher,
  52                  const uint8_t *iv, size_t niv,
  53                  Error **errp);
  54     int (*encrypt)(QCryptoCipher *cipher,
  55                    const void *in,
  56                    void *out,
  57                    size_t len,
  58                    Error **errp);
  59     int (*decrypt)(QCryptoCipher *cipher,
  60                    const void *in,
  61                    void *out,
  62                    size_t len,
  63                    Error **errp);
  64 };
  65
  66
  67 static void qcrypto_cipher_free_aes(QCryptoCipher *cipher)
  68 {
  69     QCryptoCipherBuiltin *ctxt = cipher->opaque;
  70
  71     g_free(ctxt);
  72     cipher->opaque = NULL;
  73 }
  74
  75
  76 static void qcrypto_cipher_aes_ecb_encrypt(AES_KEY *key,
  77                                            const void *in,
  78                                            void *out,
  79                                            size_t len)
  80 {
  81     const uint8_t *inptr = in;
  82     uint8_t *outptr = out;
  83     while (len) {
  84         if (len > AES_BLOCK_SIZE) {
  85             AES_encrypt(inptr, outptr, key);
  86             inptr += AES_BLOCK_SIZE;
  87             outptr += AES_BLOCK_SIZE;
  88             len -= AES_BLOCK_SIZE;
  89         } else {
  90             uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
  91             memcpy(tmp1, inptr, len);
  92             /* Fill with 0 to avoid valgrind uninitialized reads */
  93             memset(tmp1 + len, 0, sizeof(tmp1) - len);
  94             AES_encrypt(tmp1, tmp2, key);
  95             memcpy(outptr, tmp2, len);
  96             len = 0;
  97         }
  98     }
  99 }
 100
 101
 102 static void qcrypto_cipher_aes_ecb_decrypt(AES_KEY *key,
 103                                            const void *in,
 104                                            void *out,
 105                                            size_t len)
 106 {
 107     const uint8_t *inptr = in;
 108     uint8_t *outptr = out;
 109     while (len) {
 110         if (len > AES_BLOCK_SIZE) {
 111             AES_decrypt(inptr, outptr, key);
 112             inptr += AES_BLOCK_SIZE;
 113             outptr += AES_BLOCK_SIZE;
 114             len -= AES_BLOCK_SIZE;
 115         } else {
 116             uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
 117             memcpy(tmp1, inptr, len);
 118             /* Fill with 0 to avoid valgrind uninitialized reads */
 119             memset(tmp1 + len, 0, sizeof(tmp1) - len);
 120             AES_decrypt(tmp1, tmp2, key);
 121             memcpy(outptr, tmp2, len);
 122             len = 0;
 123         }
 124     }
 125 }
 126
 127
 128 static void qcrypto_cipher_aes_xts_encrypt(const void *ctx,
 129                                            size_t length,
 130                                            uint8_t *dst,
 131                                            const uint8_t *src)
 132 {
 133     const QCryptoCipherBuiltinAESContext *aesctx = ctx;
 134
 135     qcrypto_cipher_aes_ecb_encrypt((AES_KEY *)&aesctx->enc,
 136                                    src, dst, length);
 137 }
 138
 139
 140 static void qcrypto_cipher_aes_xts_decrypt(const void *ctx,
 141                                            size_t length,
 142                                            uint8_t *dst,
 143                                            const uint8_t *src)
 144 {
 145     const QCryptoCipherBuiltinAESContext *aesctx = ctx;
 146
 147     qcrypto_cipher_aes_ecb_decrypt((AES_KEY *)&aesctx->dec,
 148                                    src, dst, length);
 149 }
 150
 151
 152 static int qcrypto_cipher_encrypt_aes(QCryptoCipher *cipher,
 153                                       const void *in,
 154                                       void *out,
 155                                       size_t len,
 156                                       Error **errp)
 157 {
 158     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 159
 160     switch (cipher->mode) {
 161     case QCRYPTO_CIPHER_MODE_ECB:
 162         qcrypto_cipher_aes_ecb_encrypt(&ctxt->state.aes.key.enc,
 163                                        in, out, len);
 164         break;
 165     case QCRYPTO_CIPHER_MODE_CBC:
 166         AES_cbc_encrypt(in, out, len,
 167                         &ctxt->state.aes.key.enc,
 168                         ctxt->state.aes.iv, 1);
 169         break;
 170     case QCRYPTO_CIPHER_MODE_XTS:
 171         xts_encrypt(&ctxt->state.aes.key,
 172                     &ctxt->state.aes.key_tweak,
 173                     qcrypto_cipher_aes_xts_encrypt,
 174                     qcrypto_cipher_aes_xts_decrypt,
 175                     ctxt->state.aes.iv,
 176                     len, out, in);
 177         break;
 178     default:
 179         g_assert_not_reached();
 180     }
 181
 182     return 0;
 183 }
 184
 185
 186 static int qcrypto_cipher_decrypt_aes(QCryptoCipher *cipher,
 187                                       const void *in,
 188                                       void *out,
 189                                       size_t len,
 190                                       Error **errp)
 191 {
 192     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 193
 194     switch (cipher->mode) {
 195     case QCRYPTO_CIPHER_MODE_ECB:
 196         qcrypto_cipher_aes_ecb_decrypt(&ctxt->state.aes.key.dec,
 197                                        in, out, len);
 198         break;
 199     case QCRYPTO_CIPHER_MODE_CBC:
 200         AES_cbc_encrypt(in, out, len,
 201                         &ctxt->state.aes.key.dec,
 202                         ctxt->state.aes.iv, 0);
 203         break;
 204     case QCRYPTO_CIPHER_MODE_XTS:
 205         xts_decrypt(&ctxt->state.aes.key,
 206                     &ctxt->state.aes.key_tweak,
 207                     qcrypto_cipher_aes_xts_encrypt,
 208                     qcrypto_cipher_aes_xts_decrypt,
 209                     ctxt->state.aes.iv,
 210                     len, out, in);
 211         break;
 212     default:
 213         g_assert_not_reached();
 214     }
 215
 216     return 0;
 217 }
 218
 219 static int qcrypto_cipher_setiv_aes(QCryptoCipher *cipher,
 220                                      const uint8_t *iv, size_t niv,
 221                                      Error **errp)
 222 {
 223     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 224     if (niv != AES_BLOCK_SIZE) {
 225         error_setg(errp, "IV must be %d bytes not %zu",
 226                    AES_BLOCK_SIZE, niv);
 227         return -1;
 228     }
 229
 230     memcpy(ctxt->state.aes.iv, iv, AES_BLOCK_SIZE);
 231
 232     return 0;
 233 }
 234
 235
 236
 237
 238 static int qcrypto_cipher_init_aes(QCryptoCipher *cipher,
 239                                    const uint8_t *key, size_t nkey,
 240                                    Error **errp)
 241 {
 242     QCryptoCipherBuiltin *ctxt;
 243
 244     if (cipher->mode != QCRYPTO_CIPHER_MODE_CBC &&
 245         cipher->mode != QCRYPTO_CIPHER_MODE_ECB &&
 246         cipher->mode != QCRYPTO_CIPHER_MODE_XTS) {
 247         error_setg(errp, "Unsupported cipher mode %d", cipher->mode);
 248         return -1;
 249     }
 250
 251     ctxt = g_new0(QCryptoCipherBuiltin, 1);
 252
 253     if (cipher->mode == QCRYPTO_CIPHER_MODE_XTS) {
 254         if (AES_set_encrypt_key(key, nkey * 4, &ctxt->state.aes.key.enc) != 0) {
 255             error_setg(errp, "Failed to set encryption key");
 256             goto error;
 257         }
 258
 259         if (AES_set_decrypt_key(key, nkey * 4, &ctxt->state.aes.key.dec) != 0) {
 260             error_setg(errp, "Failed to set decryption key");
 261             goto error;
 262         }
 263
 264         if (AES_set_encrypt_key(key + (nkey / 2), nkey * 4,
 265                                 &ctxt->state.aes.key_tweak.enc) != 0) {
 266             error_setg(errp, "Failed to set encryption key");
 267             goto error;
 268         }
 269
 270         if (AES_set_decrypt_key(key + (nkey / 2), nkey * 4,
 271                                 &ctxt->state.aes.key_tweak.dec) != 0) {
 272             error_setg(errp, "Failed to set decryption key");
 273             goto error;
 274         }
 275     } else {
 276         if (AES_set_encrypt_key(key, nkey * 8, &ctxt->state.aes.key.enc) != 0) {
 277             error_setg(errp, "Failed to set encryption key");
 278             goto error;
 279         }
 280
 281         if (AES_set_decrypt_key(key, nkey * 8, &ctxt->state.aes.key.dec) != 0) {
 282             error_setg(errp, "Failed to set decryption key");
 283             goto error;
 284         }
 285     }
 286
 287     ctxt->blocksize = AES_BLOCK_SIZE;
 288     ctxt->free = qcrypto_cipher_free_aes;
 289     ctxt->setiv = qcrypto_cipher_setiv_aes;
 290     ctxt->encrypt = qcrypto_cipher_encrypt_aes;
 291     ctxt->decrypt = qcrypto_cipher_decrypt_aes;
 292
 293     cipher->opaque = ctxt;
 294
 295     return 0;
 296
 297  error:
 298     g_free(ctxt);
 299     return -1;
 300 }
 301
 302
 303 static void qcrypto_cipher_free_des_rfb(QCryptoCipher *cipher)
 304 {
 305     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 306
 307     g_free(ctxt->state.desrfb.key);
 308     g_free(ctxt);
 309     cipher->opaque = NULL;
 310 }
 311
 312
 313 static int qcrypto_cipher_encrypt_des_rfb(QCryptoCipher *cipher,
 314                                           const void *in,
 315                                           void *out,
 316                                           size_t len,
 317                                           Error **errp)
 318 {
 319     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 320     size_t i;
 321
 322     if (len % 8) {
 323         error_setg(errp, "Buffer size must be multiple of 8 not %zu",
 324                    len);
 325         return -1;
 326     }
 327
 328     deskey(ctxt->state.desrfb.key, EN0);
 329
 330     for (i = 0; i < len; i += 8) {
 331         des((void *)in + i, out + i);
 332     }
 333
 334     return 0;
 335 }
 336
 337
 338 static int qcrypto_cipher_decrypt_des_rfb(QCryptoCipher *cipher,
 339                                           const void *in,
 340                                           void *out,
 341                                           size_t len,
 342                                           Error **errp)
 343 {
 344     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 345     size_t i;
 346
 347     if (len % 8) {
 348         error_setg(errp, "Buffer size must be multiple of 8 not %zu",
 349                    len);
 350         return -1;
 351     }
 352
 353     deskey(ctxt->state.desrfb.key, DE1);
 354
 355     for (i = 0; i < len; i += 8) {
 356         des((void *)in + i, out + i);
 357     }
 358
 359     return 0;
 360 }
 361
 362
 363 static int qcrypto_cipher_setiv_des_rfb(QCryptoCipher *cipher,
 364                                         const uint8_t *iv, size_t niv,
 365                                         Error **errp)
 366 {
 367     error_setg(errp, "Setting IV is not supported");
 368     return -1;
 369 }
 370
 371
 372 static int qcrypto_cipher_init_des_rfb(QCryptoCipher *cipher,
 373                                        const uint8_t *key, size_t nkey,
 374                                        Error **errp)
 375 {
 376     QCryptoCipherBuiltin *ctxt;
 377
 378     if (cipher->mode != QCRYPTO_CIPHER_MODE_ECB) {
 379         error_setg(errp, "Unsupported cipher mode %d", cipher->mode);
 380         return -1;
 381     }
 382
 383     ctxt = g_new0(QCryptoCipherBuiltin, 1);
 384
 385     ctxt->state.desrfb.key = g_new0(uint8_t, nkey);
 386     memcpy(ctxt->state.desrfb.key, key, nkey);
 387     ctxt->state.desrfb.nkey = nkey;
 388
 389     ctxt->blocksize = 8;
 390     ctxt->free = qcrypto_cipher_free_des_rfb;
 391     ctxt->setiv = qcrypto_cipher_setiv_des_rfb;
 392     ctxt->encrypt = qcrypto_cipher_encrypt_des_rfb;
 393     ctxt->decrypt = qcrypto_cipher_decrypt_des_rfb;
 394
 395     cipher->opaque = ctxt;
 396
 397     return 0;
 398 }
 399
 400
 401 bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
 402 {
 403     switch (alg) {
 404     case QCRYPTO_CIPHER_ALG_DES_RFB:
 405     case QCRYPTO_CIPHER_ALG_AES_128:
 406     case QCRYPTO_CIPHER_ALG_AES_192:
 407     case QCRYPTO_CIPHER_ALG_AES_256:
 408         return true;
 409     default:
 410         return false;
 411     }
 412 }
 413
 414
 415 QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
 416                                   QCryptoCipherMode mode,
 417                                   const uint8_t *key, size_t nkey,
 418                                   Error **errp)
 419 {
 420     QCryptoCipher *cipher;
 421
 422     cipher = g_new0(QCryptoCipher, 1);
 423     cipher->alg = alg;
 424     cipher->mode = mode;
 425
 426     if (!qcrypto_cipher_validate_key_length(alg, mode, nkey, errp)) {
 427         goto error;
 428     }
 429
 430     switch (cipher->alg) {
 431     case QCRYPTO_CIPHER_ALG_DES_RFB:
 432         if (qcrypto_cipher_init_des_rfb(cipher, key, nkey, errp) < 0) {
 433             goto error;
 434         }
 435         break;
 436     case QCRYPTO_CIPHER_ALG_AES_128:
 437     case QCRYPTO_CIPHER_ALG_AES_192:
 438     case QCRYPTO_CIPHER_ALG_AES_256:
 439         if (qcrypto_cipher_init_aes(cipher, key, nkey, errp) < 0) {
 440             goto error;
 441         }
 442         break;
 443     default:
 444         error_setg(errp,
 445                    "Unsupported cipher algorithm %d", cipher->alg);
 446         goto error;
 447     }
 448
 449     return cipher;
 450
 451  error:
 452     g_free(cipher);
 453     return NULL;
 454 }
 455
 456 void qcrypto_cipher_free(QCryptoCipher *cipher)
 457 {
 458     QCryptoCipherBuiltin *ctxt;
 459
 460     if (!cipher) {
 461         return;
 462     }
 463
 464     ctxt = cipher->opaque;
 465     ctxt->free(cipher);
 466     g_free(cipher);
 467 }
 468
 469
 470 int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
 471                            const void *in,
 472                            void *out,
 473                            size_t len,
 474                            Error **errp)
 475 {
 476     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 477
 478     if (len % ctxt->blocksize) {
 479         error_setg(errp, "Length %zu must be a multiple of block size %zu",
 480                    len, ctxt->blocksize);
 481         return -1;
 482     }
 483
 484     return ctxt->encrypt(cipher, in, out, len, errp);
 485 }
 486
 487
 488 int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
 489                            const void *in,
 490                            void *out,
 491                            size_t len,
 492                            Error **errp)
 493 {
 494     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 495
 496     if (len % ctxt->blocksize) {
 497         error_setg(errp, "Length %zu must be a multiple of block size %zu",
 498                    len, ctxt->blocksize);
 499         return -1;
 500     }
 501
 502     return ctxt->decrypt(cipher, in, out, len, errp);
 503 }
 504
 505
 506 int qcrypto_cipher_setiv(QCryptoCipher *cipher,
 507                          const uint8_t *iv, size_t niv,
 508                          Error **errp)
 509 {
 510     QCryptoCipherBuiltin *ctxt = cipher->opaque;
 511
 512     return ctxt->setiv(cipher, iv, niv, errp);
 513 }