security/keys/trusted.c

   1 /*
   2  * Copyright (C) 2010 IBM Corporation
   3  *
   4  * Author:
   5  * David Safford <safford@us.ibm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation, version 2 of the License.
  10  *
  11  * See Documentation/security/keys-trusted-encrypted.txt
  12  */
  13
  14 #include <linux/uaccess.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18 #include <linux/parser.h>
  19 #include <linux/string.h>
  20 #include <linux/err.h>
  21 #include <keys/user-type.h>
  22 #include <keys/trusted-type.h>
  23 #include <linux/key-type.h>
  24 #include <linux/rcupdate.h>
  25 #include <linux/crypto.h>
  26 #include <crypto/hash.h>
  27 #include <crypto/sha.h>
  28 #include <linux/capability.h>
  29 #include <linux/tpm.h>
  30 #include <linux/tpm_command.h>
  31
  32 #include "trusted.h"
  33
  34 static const char hmac_alg[] = "hmac(sha1)";
  35 static const char hash_alg[] = "sha1";
  36
  37 struct sdesc {
  38         struct shash_desc shash;
  39         char ctx[];
  40 };
  41
  42 static struct crypto_shash *hashalg;
  43 static struct crypto_shash *hmacalg;
  44
  45 static struct sdesc *init_sdesc(struct crypto_shash *alg)
  46 {
  47         struct sdesc *sdesc;
  48         int size;
  49
  50         size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
  51         sdesc = kmalloc(size, GFP_KERNEL);
  52         if (!sdesc)
  53                 return ERR_PTR(-ENOMEM);
  54         sdesc->shash.tfm = alg;
  55         sdesc->shash.flags = 0x0;
  56         return sdesc;
  57 }
  58
  59 static int TSS_sha1(const unsigned char *data, unsigned int datalen,
  60                     unsigned char *digest)
  61 {
  62         struct sdesc *sdesc;
  63         int ret;
  64
  65         sdesc = init_sdesc(hashalg);
  66         if (IS_ERR(sdesc)) {
  67                 pr_info("trusted_key: can't alloc %s\n", hash_alg);
  68                 return PTR_ERR(sdesc);
  69         }
  70
  71         ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
  72         kfree(sdesc);
  73         return ret;
  74 }
  75
  76 static int TSS_rawhmac(unsigned char *digest, const unsigned char *key,
  77                        unsigned int keylen, ...)
  78 {
  79         struct sdesc *sdesc;
  80         va_list argp;
  81         unsigned int dlen;
  82         unsigned char *data;
  83         int ret;
  84
  85         sdesc = init_sdesc(hmacalg);
  86         if (IS_ERR(sdesc)) {
  87                 pr_info("trusted_key: can't alloc %s\n", hmac_alg);
  88                 return PTR_ERR(sdesc);
  89         }
  90
  91         ret = crypto_shash_setkey(hmacalg, key, keylen);
  92         if (ret < 0)
  93                 goto out;
  94         ret = crypto_shash_init(&sdesc->shash);
  95         if (ret < 0)
  96                 goto out;
  97
  98         va_start(argp, keylen);
  99         for (;;) {
 100                 dlen = va_arg(argp, unsigned int);
 101                 if (dlen == 0)
 102                         break;
 103                 data = va_arg(argp, unsigned char *);
 104                 if (data == NULL) {
 105                         ret = -EINVAL;
 106                         break;
 107                 }
 108                 ret = crypto_shash_update(&sdesc->shash, data, dlen);
 109                 if (ret < 0)
 110                         break;
 111         }
 112         va_end(argp);
 113         if (!ret)
 114                 ret = crypto_shash_final(&sdesc->shash, digest);
 115 out:
 116         kfree(sdesc);
 117         return ret;
 118 }
 119
 120 /*
 121  * calculate authorization info fields to send to TPM
 122  */
 123 static int TSS_authhmac(unsigned char *digest, const unsigned char *key,
 124                         unsigned int keylen, unsigned char *h1,
 125                         unsigned char *h2, unsigned char h3, ...)
 126 {
 127         unsigned char paramdigest[SHA1_DIGEST_SIZE];
 128         struct sdesc *sdesc;
 129         unsigned int dlen;
 130         unsigned char *data;
 131         unsigned char c;
 132         int ret;
 133         va_list argp;
 134
 135         sdesc = init_sdesc(hashalg);
 136         if (IS_ERR(sdesc)) {
 137                 pr_info("trusted_key: can't alloc %s\n", hash_alg);
 138                 return PTR_ERR(sdesc);
 139         }
 140
 141         c = h3;
 142         ret = crypto_shash_init(&sdesc->shash);
 143         if (ret < 0)
 144                 goto out;
 145         va_start(argp, h3);
 146         for (;;) {
 147                 dlen = va_arg(argp, unsigned int);
 148                 if (dlen == 0)
 149                         break;
 150                 data = va_arg(argp, unsigned char *);
 151                 if (!data) {
 152                         ret = -EINVAL;
 153                         break;
 154                 }
 155                 ret = crypto_shash_update(&sdesc->shash, data, dlen);
 156                 if (ret < 0)
 157                         break;
 158         }
 159         va_end(argp);
 160         if (!ret)
 161                 ret = crypto_shash_final(&sdesc->shash, paramdigest);
 162         if (!ret)
 163                 ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
 164                                   paramdigest, TPM_NONCE_SIZE, h1,
 165                                   TPM_NONCE_SIZE, h2, 1, &c, 0, 0);
 166 out:
 167         kfree(sdesc);
 168         return ret;
 169 }
 170
 171 /*
 172  * verify the AUTH1_COMMAND (Seal) result from TPM
 173  */
 174 static int TSS_checkhmac1(unsigned char *buffer,
 175                           const uint32_t command,
 176                           const unsigned char *ononce,
 177                           const unsigned char *key,
 178                           unsigned int keylen, ...)
 179 {
 180         uint32_t bufsize;
 181         uint16_t tag;
 182         uint32_t ordinal;
 183         uint32_t result;
 184         unsigned char *enonce;
 185         unsigned char *continueflag;
 186         unsigned char *authdata;
 187         unsigned char testhmac[SHA1_DIGEST_SIZE];
 188         unsigned char paramdigest[SHA1_DIGEST_SIZE];
 189         struct sdesc *sdesc;
 190         unsigned int dlen;
 191         unsigned int dpos;
 192         va_list argp;
 193         int ret;
 194
 195         bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
 196         tag = LOAD16(buffer, 0);
 197         ordinal = command;
 198         result = LOAD32N(buffer, TPM_RETURN_OFFSET);
 199         if (tag == TPM_TAG_RSP_COMMAND)
 200                 return 0;
 201         if (tag != TPM_TAG_RSP_AUTH1_COMMAND)
 202                 return -EINVAL;
 203         authdata = buffer + bufsize - SHA1_DIGEST_SIZE;
 204         continueflag = authdata - 1;
 205         enonce = continueflag - TPM_NONCE_SIZE;
 206
 207         sdesc = init_sdesc(hashalg);
 208         if (IS_ERR(sdesc)) {
 209                 pr_info("trusted_key: can't alloc %s\n", hash_alg);
 210                 return PTR_ERR(sdesc);
 211         }
 212         ret = crypto_shash_init(&sdesc->shash);
 213         if (ret < 0)
 214                 goto out;
 215         ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
 216                                   sizeof result);
 217         if (ret < 0)
 218                 goto out;
 219         ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
 220                                   sizeof ordinal);
 221         if (ret < 0)
 222                 goto out;
 223         va_start(argp, keylen);
 224         for (;;) {
 225                 dlen = va_arg(argp, unsigned int);
 226                 if (dlen == 0)
 227                         break;
 228                 dpos = va_arg(argp, unsigned int);
 229                 ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
 230                 if (ret < 0)
 231                         break;
 232         }
 233         va_end(argp);
 234         if (!ret)
 235                 ret = crypto_shash_final(&sdesc->shash, paramdigest);
 236         if (ret < 0)
 237                 goto out;
 238
 239         ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest,
 240                           TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce,
 241                           1, continueflag, 0, 0);
 242         if (ret < 0)
 243                 goto out;
 244
 245         if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))
 246                 ret = -EINVAL;
 247 out:
 248         kfree(sdesc);
 249         return ret;
 250 }
 251
 252 /*
 253  * verify the AUTH2_COMMAND (unseal) result from TPM
 254  */
 255 static int TSS_checkhmac2(unsigned char *buffer,
 256                           const uint32_t command,
 257                           const unsigned char *ononce,
 258                           const unsigned char *key1,
 259                           unsigned int keylen1,
 260                           const unsigned char *key2,
 261                           unsigned int keylen2, ...)
 262 {
 263         uint32_t bufsize;
 264         uint16_t tag;
 265         uint32_t ordinal;
 266         uint32_t result;
 267         unsigned char *enonce1;
 268         unsigned char *continueflag1;
 269         unsigned char *authdata1;
 270         unsigned char *enonce2;
 271         unsigned char *continueflag2;
 272         unsigned char *authdata2;
 273         unsigned char testhmac1[SHA1_DIGEST_SIZE];
 274         unsigned char testhmac2[SHA1_DIGEST_SIZE];
 275         unsigned char paramdigest[SHA1_DIGEST_SIZE];
 276         struct sdesc *sdesc;
 277         unsigned int dlen;
 278         unsigned int dpos;
 279         va_list argp;
 280         int ret;
 281
 282         bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
 283         tag = LOAD16(buffer, 0);
 284         ordinal = command;
 285         result = LOAD32N(buffer, TPM_RETURN_OFFSET);
 286
 287         if (tag == TPM_TAG_RSP_COMMAND)
 288                 return 0;
 289         if (tag != TPM_TAG_RSP_AUTH2_COMMAND)
 290                 return -EINVAL;
 291         authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1
 292                         + SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE);
 293         authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE);
 294         continueflag1 = authdata1 - 1;
 295         continueflag2 = authdata2 - 1;
 296         enonce1 = continueflag1 - TPM_NONCE_SIZE;
 297         enonce2 = continueflag2 - TPM_NONCE_SIZE;
 298
 299         sdesc = init_sdesc(hashalg);
 300         if (IS_ERR(sdesc)) {
 301                 pr_info("trusted_key: can't alloc %s\n", hash_alg);
 302                 return PTR_ERR(sdesc);
 303         }
 304         ret = crypto_shash_init(&sdesc->shash);
 305         if (ret < 0)
 306                 goto out;
 307         ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
 308                                   sizeof result);
 309         if (ret < 0)
 310                 goto out;
 311         ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
 312                                   sizeof ordinal);
 313         if (ret < 0)
 314                 goto out;
 315
 316         va_start(argp, keylen2);
 317         for (;;) {
 318                 dlen = va_arg(argp, unsigned int);
 319                 if (dlen == 0)
 320                         break;
 321                 dpos = va_arg(argp, unsigned int);
 322                 ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);
 323                 if (ret < 0)
 324                         break;
 325         }
 326         va_end(argp);
 327         if (!ret)
 328                 ret = crypto_shash_final(&sdesc->shash, paramdigest);
 329         if (ret < 0)
 330                 goto out;
 331
 332         ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE,
 333                           paramdigest, TPM_NONCE_SIZE, enonce1,
 334                           TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0);
 335         if (ret < 0)
 336                 goto out;
 337         if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) {
 338                 ret = -EINVAL;
 339                 goto out;
 340         }
 341         ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE,
 342                           paramdigest, TPM_NONCE_SIZE, enonce2,
 343                           TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0);
 344         if (ret < 0)
 345                 goto out;
 346         if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))
 347                 ret = -EINVAL;
 348 out:
 349         kfree(sdesc);
 350         return ret;
 351 }
 352
 353 /*
 354  * For key specific tpm requests, we will generate and send our
 355  * own TPM command packets using the drivers send function.
 356  */
 357 static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd,
 358                             size_t buflen)
 359 {
 360         int rc;
 361
 362         dump_tpm_buf(cmd);
 363         rc = tpm_send(chip_num, cmd, buflen);
 364         dump_tpm_buf(cmd);
 365         if (rc > 0)
 366                 /* Can't return positive return codes values to keyctl */
 367                 rc = -EPERM;
 368         return rc;
 369 }
 370
 371 /*
 372  * get a random value from TPM
 373  */
 374 static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len)
 375 {
 376         int ret;
 377
 378         INIT_BUF(tb);
 379         store16(tb, TPM_TAG_RQU_COMMAND);
 380         store32(tb, TPM_GETRANDOM_SIZE);
 381         store32(tb, TPM_ORD_GETRANDOM);
 382         store32(tb, len);
 383         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data);
 384         if (!ret)
 385                 memcpy(buf, tb->data + TPM_GETRANDOM_SIZE, len);
 386         return ret;
 387 }
 388
 389 static int my_get_random(unsigned char *buf, int len)
 390 {
 391         struct tpm_buf *tb;
 392         int ret;
 393
 394         tb = kmalloc(sizeof *tb, GFP_KERNEL);
 395         if (!tb)
 396                 return -ENOMEM;
 397         ret = tpm_get_random(tb, buf, len);
 398
 399         kfree(tb);
 400         return ret;
 401 }
 402
 403 /*
 404  * Lock a trusted key, by extending a selected PCR.
 405  *
 406  * Prevents a trusted key that is sealed to PCRs from being accessed.
 407  * This uses the tpm driver's extend function.
 408  */
 409 static int pcrlock(const int pcrnum)
 410 {
 411         unsigned char hash[SHA1_DIGEST_SIZE];
 412         int ret;
 413
 414         if (!capable(CAP_SYS_ADMIN))
 415                 return -EPERM;
 416         ret = my_get_random(hash, SHA1_DIGEST_SIZE);
 417         if (ret < 0)
 418                 return ret;
 419         return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
 420 }
 421
 422 /*
 423  * Create an object specific authorisation protocol (OSAP) session
 424  */
 425 static int osap(struct tpm_buf *tb, struct osapsess *s,
 426                 const unsigned char *key, uint16_t type, uint32_t handle)
 427 {
 428         unsigned char enonce[TPM_NONCE_SIZE];
 429         unsigned char ononce[TPM_NONCE_SIZE];
 430         int ret;
 431
 432         ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE);
 433         if (ret < 0)
 434                 return ret;
 435
 436         INIT_BUF(tb);
 437         store16(tb, TPM_TAG_RQU_COMMAND);
 438         store32(tb, TPM_OSAP_SIZE);
 439         store32(tb, TPM_ORD_OSAP);
 440         store16(tb, type);
 441         store32(tb, handle);
 442         storebytes(tb, ononce, TPM_NONCE_SIZE);
 443
 444         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
 445         if (ret < 0)
 446                 return ret;
 447
 448         s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
 449         memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
 450                TPM_NONCE_SIZE);
 451         memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
 452                                   TPM_NONCE_SIZE]), TPM_NONCE_SIZE);
 453         return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
 454                            enonce, TPM_NONCE_SIZE, ononce, 0, 0);
 455 }
 456
 457 /*
 458  * Create an object independent authorisation protocol (oiap) session
 459  */
 460 static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
 461 {
 462         int ret;
 463
 464         INIT_BUF(tb);
 465         store16(tb, TPM_TAG_RQU_COMMAND);
 466         store32(tb, TPM_OIAP_SIZE);
 467         store32(tb, TPM_ORD_OIAP);
 468         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
 469         if (ret < 0)
 470                 return ret;
 471
 472         *handle = LOAD32(tb->data, TPM_DATA_OFFSET);
 473         memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
 474                TPM_NONCE_SIZE);
 475         return 0;
 476 }
 477
 478 struct tpm_digests {
 479         unsigned char encauth[SHA1_DIGEST_SIZE];
 480         unsigned char pubauth[SHA1_DIGEST_SIZE];
 481         unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
 482         unsigned char xorhash[SHA1_DIGEST_SIZE];
 483         unsigned char nonceodd[TPM_NONCE_SIZE];
 484 };
 485
 486 /*
 487  * Have the TPM seal(encrypt) the trusted key, possibly based on
 488  * Platform Configuration Registers (PCRs). AUTH1 for sealing key.
 489  */
 490 static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
 491                     uint32_t keyhandle, const unsigned char *keyauth,
 492                     const unsigned char *data, uint32_t datalen,
 493                     unsigned char *blob, uint32_t *bloblen,
 494                     const unsigned char *blobauth,
 495                     const unsigned char *pcrinfo, uint32_t pcrinfosize)
 496 {
 497         struct osapsess sess;
 498         struct tpm_digests *td;
 499         unsigned char cont;
 500         uint32_t ordinal;
 501         uint32_t pcrsize;
 502         uint32_t datsize;
 503         int sealinfosize;
 504         int encdatasize;
 505         int storedsize;
 506         int ret;
 507         int i;
 508
 509         /* alloc some work space for all the hashes */
 510         td = kmalloc(sizeof *td, GFP_KERNEL);
 511         if (!td)
 512                 return -ENOMEM;
 513
 514         /* get session for sealing key */
 515         ret = osap(tb, &sess, keyauth, keytype, keyhandle);
 516         if (ret < 0)
 517                 goto out;
 518         dump_sess(&sess);
 519
 520         /* calculate encrypted authorization value */
 521         memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
 522         memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
 523         ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
 524         if (ret < 0)
 525                 goto out;
 526
 527         ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE);
 528         if (ret < 0)
 529                 goto out;
 530         ordinal = htonl(TPM_ORD_SEAL);
 531         datsize = htonl(datalen);
 532         pcrsize = htonl(pcrinfosize);
 533         cont = 0;
 534
 535         /* encrypt data authorization key */
 536         for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
 537                 td->encauth[i] = td->xorhash[i] ^ blobauth[i];
 538
 539         /* calculate authorization HMAC value */
 540         if (pcrinfosize == 0) {
 541                 /* no pcr info specified */
 542                 ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
 543                                    sess.enonce, td->nonceodd, cont,
 544                                    sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
 545                                    td->encauth, sizeof(uint32_t), &pcrsize,
 546                                    sizeof(uint32_t), &datsize, datalen, data, 0,
 547                                    0);
 548         } else {
 549                 /* pcr info specified */
 550                 ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
 551                                    sess.enonce, td->nonceodd, cont,
 552                                    sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
 553                                    td->encauth, sizeof(uint32_t), &pcrsize,
 554                                    pcrinfosize, pcrinfo, sizeof(uint32_t),
 555                                    &datsize, datalen, data, 0, 0);
 556         }
 557         if (ret < 0)
 558                 goto out;
 559
 560         /* build and send the TPM request packet */
 561         INIT_BUF(tb);
 562         store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
 563         store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen);
 564         store32(tb, TPM_ORD_SEAL);
 565         store32(tb, keyhandle);
 566         storebytes(tb, td->encauth, SHA1_DIGEST_SIZE);
 567         store32(tb, pcrinfosize);
 568         storebytes(tb, pcrinfo, pcrinfosize);
 569         store32(tb, datalen);
 570         storebytes(tb, data, datalen);
 571         store32(tb, sess.handle);
 572         storebytes(tb, td->nonceodd, TPM_NONCE_SIZE);
 573         store8(tb, cont);
 574         storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
 575
 576         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
 577         if (ret < 0)
 578                 goto out;
 579
 580         /* calculate the size of the returned Blob */
 581         sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t));
 582         encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) +
 583                              sizeof(uint32_t) + sealinfosize);
 584         storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize +
 585             sizeof(uint32_t) + encdatasize;
 586
 587         /* check the HMAC in the response */
 588         ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret,
 589                              SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0,
 590                              0);
 591
 592         /* copy the returned blob to caller */
 593         if (!ret) {
 594                 memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
 595                 *bloblen = storedsize;
 596         }
 597 out:
 598         kfree(td);
 599         return ret;
 600 }
 601
 602 /*
 603  * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
 604  */
 605 static int tpm_unseal(struct tpm_buf *tb,
 606                       uint32_t keyhandle, const unsigned char *keyauth,
 607                       const unsigned char *blob, int bloblen,
 608                       const unsigned char *blobauth,
 609                       unsigned char *data, unsigned int *datalen)
 610 {
 611         unsigned char nonceodd[TPM_NONCE_SIZE];
 612         unsigned char enonce1[TPM_NONCE_SIZE];
 613         unsigned char enonce2[TPM_NONCE_SIZE];
 614         unsigned char authdata1[SHA1_DIGEST_SIZE];
 615         unsigned char authdata2[SHA1_DIGEST_SIZE];
 616         uint32_t authhandle1 = 0;
 617         uint32_t authhandle2 = 0;
 618         unsigned char cont = 0;
 619         uint32_t ordinal;
 620         uint32_t keyhndl;
 621         int ret;
 622
 623         /* sessions for unsealing key and data */
 624         ret = oiap(tb, &authhandle1, enonce1);
 625         if (ret < 0) {
 626                 pr_info("trusted_key: oiap failed (%d)\n", ret);
 627                 return ret;
 628         }
 629         ret = oiap(tb, &authhandle2, enonce2);
 630         if (ret < 0) {
 631                 pr_info("trusted_key: oiap failed (%d)\n", ret);
 632                 return ret;
 633         }
 634
 635         ordinal = htonl(TPM_ORD_UNSEAL);
 636         keyhndl = htonl(SRKHANDLE);
 637         ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE);
 638         if (ret < 0) {
 639                 pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
 640                 return ret;
 641         }
 642         ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
 643                            enonce1, nonceodd, cont, sizeof(uint32_t),
 644                            &ordinal, bloblen, blob, 0, 0);
 645         if (ret < 0)
 646                 return ret;
 647         ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
 648                            enonce2, nonceodd, cont, sizeof(uint32_t),
 649                            &ordinal, bloblen, blob, 0, 0);
 650         if (ret < 0)
 651                 return ret;
 652
 653         /* build and send TPM request packet */
 654         INIT_BUF(tb);
 655         store16(tb, TPM_TAG_RQU_AUTH2_COMMAND);
 656         store32(tb, TPM_UNSEAL_SIZE + bloblen);
 657         store32(tb, TPM_ORD_UNSEAL);
 658         store32(tb, keyhandle);
 659         storebytes(tb, blob, bloblen);
 660         store32(tb, authhandle1);
 661         storebytes(tb, nonceodd, TPM_NONCE_SIZE);
 662         store8(tb, cont);
 663         storebytes(tb, authdata1, SHA1_DIGEST_SIZE);
 664         store32(tb, authhandle2);
 665         storebytes(tb, nonceodd, TPM_NONCE_SIZE);
 666         store8(tb, cont);
 667         storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
 668
 669         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
 670         if (ret < 0) {
 671                 pr_info("trusted_key: authhmac failed (%d)\n", ret);
 672                 return ret;
 673         }
 674
 675         *datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
 676         ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
 677                              keyauth, SHA1_DIGEST_SIZE,
 678                              blobauth, SHA1_DIGEST_SIZE,
 679                              sizeof(uint32_t), TPM_DATA_OFFSET,
 680                              *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
 681                              0);
 682         if (ret < 0) {
 683                 pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret);
 684                 return ret;
 685         }
 686         memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
 687         return 0;
 688 }
 689
 690 /*
 691  * Have the TPM seal(encrypt) the symmetric key
 692  */
 693 static int key_seal(struct trusted_key_payload *p,
 694                     struct trusted_key_options *o)
 695 {
 696         struct tpm_buf *tb;
 697         int ret;
 698
 699         tb = kzalloc(sizeof *tb, GFP_KERNEL);
 700         if (!tb)
 701                 return -ENOMEM;
 702
 703         /* include migratable flag at end of sealed key */
 704         p->key[p->key_len] = p->migratable;
 705
 706         ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
 707                        p->key, p->key_len + 1, p->blob, &p->blob_len,
 708                        o->blobauth, o->pcrinfo, o->pcrinfo_len);
 709         if (ret < 0)
 710                 pr_info("trusted_key: srkseal failed (%d)\n", ret);
 711
 712         kfree(tb);
 713         return ret;
 714 }
 715
 716 /*
 717  * Have the TPM unseal(decrypt) the symmetric key
 718  */
 719 static int key_unseal(struct trusted_key_payload *p,
 720                       struct trusted_key_options *o)
 721 {
 722         struct tpm_buf *tb;
 723         int ret;
 724
 725         tb = kzalloc(sizeof *tb, GFP_KERNEL);
 726         if (!tb)
 727                 return -ENOMEM;
 728
 729         ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
 730                          o->blobauth, p->key, &p->key_len);
 731         if (ret < 0)
 732                 pr_info("trusted_key: srkunseal failed (%d)\n", ret);
 733         else
 734                 /* pull migratable flag out of sealed key */
 735                 p->migratable = p->key[--p->key_len];
 736
 737         kfree(tb);
 738         return ret;
 739 }
 740
 741 enum {
 742         Opt_err = -1,
 743         Opt_new, Opt_load, Opt_update,
 744         Opt_keyhandle, Opt_keyauth, Opt_blobauth,
 745         Opt_pcrinfo, Opt_pcrlock, Opt_migratable
 746 };
 747
 748 static const match_table_t key_tokens = {
 749         {Opt_new, "new"},
 750         {Opt_load, "load"},
 751         {Opt_update, "update"},
 752         {Opt_keyhandle, "keyhandle=%s"},
 753         {Opt_keyauth, "keyauth=%s"},
 754         {Opt_blobauth, "blobauth=%s"},
 755         {Opt_pcrinfo, "pcrinfo=%s"},
 756         {Opt_pcrlock, "pcrlock=%s"},
 757         {Opt_migratable, "migratable=%s"},
 758         {Opt_err, NULL}
 759 };
 760
 761 /* can have zero or more token= options */
 762 static int getoptions(char *c, struct trusted_key_payload *pay,
 763                       struct trusted_key_options *opt)
 764 {
 765         substring_t args[MAX_OPT_ARGS];
 766         char *p = c;
 767         int token;
 768         int res;
 769         unsigned long handle;
 770         unsigned long lock;
 771
 772         while ((p = strsep(&c, " \t"))) {
 773                 if (*p == '\0' || *p == ' ' || *p == '\t')
 774                         continue;
 775                 token = match_token(p, key_tokens, args);
 776
 777                 switch (token) {
 778                 case Opt_pcrinfo:
 779                         opt->pcrinfo_len = strlen(args[0].from) / 2;
 780                         if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
 781                                 return -EINVAL;
 782                         res = hex2bin(opt->pcrinfo, args[0].from,
 783                                       opt->pcrinfo_len);
 784                         if (res < 0)
 785                                 return -EINVAL;
 786                         break;
 787                 case Opt_keyhandle:
 788                         res = strict_strtoul(args[0].from, 16, &handle);
 789                         if (res < 0)
 790                                 return -EINVAL;
 791                         opt->keytype = SEAL_keytype;
 792                         opt->keyhandle = handle;
 793                         break;
 794                 case Opt_keyauth:
 795                         if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
 796                                 return -EINVAL;
 797                         res = hex2bin(opt->keyauth, args[0].from,
 798                                       SHA1_DIGEST_SIZE);
 799                         if (res < 0)
 800                                 return -EINVAL;
 801                         break;
 802                 case Opt_blobauth:
 803                         if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
 804                                 return -EINVAL;
 805                         res = hex2bin(opt->blobauth, args[0].from,
 806                                       SHA1_DIGEST_SIZE);
 807                         if (res < 0)
 808                                 return -EINVAL;
 809                         break;
 810                 case Opt_migratable:
 811                         if (*args[0].from == '0')
 812                                 pay->migratable = 0;
 813                         else
 814                                 return -EINVAL;
 815                         break;
 816                 case Opt_pcrlock:
 817                         res = strict_strtoul(args[0].from, 10, &lock);
 818                         if (res < 0)
 819                                 return -EINVAL;
 820                         opt->pcrlock = lock;
 821                         break;
 822                 default:
 823                         return -EINVAL;
 824                 }
 825         }
 826         return 0;
 827 }
 828
 829 /*
 830  * datablob_parse - parse the keyctl data and fill in the
 831  *                  payload and options structures
 832  *
 833  * On success returns 0, otherwise -EINVAL.
 834  */
 835 static int datablob_parse(char *datablob, struct trusted_key_payload *p,
 836                           struct trusted_key_options *o)
 837 {
 838         substring_t args[MAX_OPT_ARGS];
 839         long keylen;
 840         int ret = -EINVAL;
 841         int key_cmd;
 842         char *c;
 843
 844         /* main command */
 845         c = strsep(&datablob, " \t");
 846         if (!c)
 847                 return -EINVAL;
 848         key_cmd = match_token(c, key_tokens, args);
 849         switch (key_cmd) {
 850         case Opt_new:
 851                 /* first argument is key size */
 852                 c = strsep(&datablob, " \t");
 853                 if (!c)
 854                         return -EINVAL;
 855                 ret = strict_strtol(c, 10, &keylen);
 856                 if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
 857                         return -EINVAL;
 858                 p->key_len = keylen;
 859                 ret = getoptions(datablob, p, o);
 860                 if (ret < 0)
 861                         return ret;
 862                 ret = Opt_new;
 863                 break;
 864         case Opt_load:
 865                 /* first argument is sealed blob */
 866                 c = strsep(&datablob, " \t");
 867                 if (!c)
 868                         return -EINVAL;
 869                 p->blob_len = strlen(c) / 2;
 870                 if (p->blob_len > MAX_BLOB_SIZE)
 871                         return -EINVAL;
 872                 ret = hex2bin(p->blob, c, p->blob_len);
 873                 if (ret < 0)
 874                         return -EINVAL;
 875                 ret = getoptions(datablob, p, o);
 876                 if (ret < 0)
 877                         return ret;
 878                 ret = Opt_load;
 879                 break;
 880         case Opt_update:
 881                 /* all arguments are options */
 882                 ret = getoptions(datablob, p, o);
 883                 if (ret < 0)
 884                         return ret;
 885                 ret = Opt_update;
 886                 break;
 887         case Opt_err:
 888                 return -EINVAL;
 889                 break;
 890         }
 891         return ret;
 892 }
 893
 894 static struct trusted_key_options *trusted_options_alloc(void)
 895 {
 896         struct trusted_key_options *options;
 897
 898         options = kzalloc(sizeof *options, GFP_KERNEL);
 899         if (options) {
 900                 /* set any non-zero defaults */
 901                 options->keytype = SRK_keytype;
 902                 options->keyhandle = SRKHANDLE;
 903         }
 904         return options;
 905 }
 906
 907 static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
 908 {
 909         struct trusted_key_payload *p = NULL;
 910         int ret;
 911
 912         ret = key_payload_reserve(key, sizeof *p);
 913         if (ret < 0)
 914                 return p;
 915         p = kzalloc(sizeof *p, GFP_KERNEL);
 916         if (p)
 917                 p->migratable = 1; /* migratable by default */
 918         return p;
 919 }
 920
 921 /*
 922  * trusted_instantiate - create a new trusted key
 923  *
 924  * Unseal an existing trusted blob or, for a new key, get a
 925  * random key, then seal and create a trusted key-type key,
 926  * adding it to the specified keyring.
 927  *
 928  * On success, return 0. Otherwise return errno.
 929  */
 930 static int trusted_instantiate(struct key *key, const void *data,
 931                                size_t datalen)
 932 {
 933         struct trusted_key_payload *payload = NULL;
 934         struct trusted_key_options *options = NULL;
 935         char *datablob;
 936         int ret = 0;
 937         int key_cmd;
 938
 939         if (datalen <= 0 || datalen > 32767 || !data)
 940                 return -EINVAL;
 941
 942         datablob = kmalloc(datalen + 1, GFP_KERNEL);
 943         if (!datablob)
 944                 return -ENOMEM;
 945         memcpy(datablob, data, datalen);
 946         datablob[datalen] = '\0';
 947
 948         options = trusted_options_alloc();
 949         if (!options) {
 950                 ret = -ENOMEM;
 951                 goto out;
 952         }
 953         payload = trusted_payload_alloc(key);
 954         if (!payload) {
 955                 ret = -ENOMEM;
 956                 goto out;
 957         }
 958
 959         key_cmd = datablob_parse(datablob, payload, options);
 960         if (key_cmd < 0) {
 961                 ret = key_cmd;
 962                 goto out;
 963         }
 964
 965         dump_payload(payload);
 966         dump_options(options);
 967
 968         switch (key_cmd) {
 969         case Opt_load:
 970                 ret = key_unseal(payload, options);
 971                 dump_payload(payload);
 972                 dump_options(options);
 973                 if (ret < 0)
 974                         pr_info("trusted_key: key_unseal failed (%d)\n", ret);
 975                 break;
 976         case Opt_new:
 977                 ret = my_get_random(payload->key, payload->key_len);
 978                 if (ret < 0) {
 979                         pr_info("trusted_key: key_create failed (%d)\n", ret);
 980                         goto out;
 981                 }
 982                 ret = key_seal(payload, options);
 983                 if (ret < 0)
 984                         pr_info("trusted_key: key_seal failed (%d)\n", ret);
 985                 break;
 986         default:
 987                 ret = -EINVAL;
 988                 goto out;
 989         }
 990         if (!ret && options->pcrlock)
 991                 ret = pcrlock(options->pcrlock);
 992 out:
 993         kfree(datablob);
 994         kfree(options);
 995         if (!ret)
 996                 rcu_assign_pointer(key->payload.data, payload);
 997         else
 998                 kfree(payload);
 999         return ret;
1000 }
1001
1002 static void trusted_rcu_free(struct rcu_head *rcu)
1003 {
1004         struct trusted_key_payload *p;
1005
1006         p = container_of(rcu, struct trusted_key_payload, rcu);
1007         memset(p->key, 0, p->key_len);
1008         kfree(p);
1009 }
1010
1011 /*
1012  * trusted_update - reseal an existing key with new PCR values
1013  */
1014 static int trusted_update(struct key *key, const void *data, size_t datalen)
1015 {
1016         struct trusted_key_payload *p = key->payload.data;
1017         struct trusted_key_payload *new_p;
1018         struct trusted_key_options *new_o;
1019         char *datablob;
1020         int ret = 0;
1021
1022         if (!p->migratable)
1023                 return -EPERM;
1024         if (datalen <= 0 || datalen > 32767 || !data)
1025                 return -EINVAL;
1026
1027         datablob = kmalloc(datalen + 1, GFP_KERNEL);
1028         if (!datablob)
1029                 return -ENOMEM;
1030         new_o = trusted_options_alloc();
1031         if (!new_o) {
1032                 ret = -ENOMEM;
1033                 goto out;
1034         }
1035         new_p = trusted_payload_alloc(key);
1036         if (!new_p) {
1037                 ret = -ENOMEM;
1038                 goto out;
1039         }
1040
1041         memcpy(datablob, data, datalen);
1042         datablob[datalen] = '\0';
1043         ret = datablob_parse(datablob, new_p, new_o);
1044         if (ret != Opt_update) {
1045                 ret = -EINVAL;
1046                 kfree(new_p);
1047                 goto out;
1048         }
1049         /* copy old key values, and reseal with new pcrs */
1050         new_p->migratable = p->migratable;
1051         new_p->key_len = p->key_len;
1052         memcpy(new_p->key, p->key, p->key_len);
1053         dump_payload(p);
1054         dump_payload(new_p);
1055
1056         ret = key_seal(new_p, new_o);
1057         if (ret < 0) {
1058                 pr_info("trusted_key: key_seal failed (%d)\n", ret);
1059                 kfree(new_p);
1060                 goto out;
1061         }
1062         if (new_o->pcrlock) {
1063                 ret = pcrlock(new_o->pcrlock);
1064                 if (ret < 0) {
1065                         pr_info("trusted_key: pcrlock failed (%d)\n", ret);
1066                         kfree(new_p);
1067                         goto out;
1068                 }
1069         }
1070         rcu_assign_pointer(key->payload.data, new_p);
1071         call_rcu(&p->rcu, trusted_rcu_free);
1072 out:
1073         kfree(datablob);
1074         kfree(new_o);
1075         return ret;
1076 }
1077
1078 /*
1079  * trusted_read - copy the sealed blob data to userspace in hex.
1080  * On success, return to userspace the trusted key datablob size.
1081  */
1082 static long trusted_read(const struct key *key, char __user *buffer,
1083                          size_t buflen)
1084 {
1085         struct trusted_key_payload *p;
1086         char *ascii_buf;
1087         char *bufp;
1088         int i;
1089
1090         p = rcu_dereference_key(key);
1091         if (!p)
1092                 return -EINVAL;
1093         if (!buffer || buflen <= 0)
1094                 return 2 * p->blob_len;
1095         ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
1096         if (!ascii_buf)
1097                 return -ENOMEM;
1098
1099         bufp = ascii_buf;
1100         for (i = 0; i < p->blob_len; i++)
1101                 bufp = hex_byte_pack(bufp, p->blob[i]);
1102         if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
1103                 kfree(ascii_buf);
1104                 return -EFAULT;
1105         }
1106         kfree(ascii_buf);
1107         return 2 * p->blob_len;
1108 }
1109
1110 /*
1111  * trusted_destroy - before freeing the key, clear the decrypted data
1112  */
1113 static void trusted_destroy(struct key *key)
1114 {
1115         struct trusted_key_payload *p = key->payload.data;
1116
1117         if (!p)
1118                 return;
1119         memset(p->key, 0, p->key_len);
1120         kfree(key->payload.data);
1121 }
1122
1123 struct key_type key_type_trusted = {
1124         .name = "trusted",
1125         .instantiate = trusted_instantiate,
1126         .update = trusted_update,
1127         .match = user_match,
1128         .destroy = trusted_destroy,
1129         .describe = user_describe,
1130         .read = trusted_read,
1131 };
1132
1133 EXPORT_SYMBOL_GPL(key_type_trusted);
1134
1135 static void trusted_shash_release(void)
1136 {
1137         if (hashalg)
1138                 crypto_free_shash(hashalg);
1139         if (hmacalg)
1140                 crypto_free_shash(hmacalg);
1141 }
1142
1143 static int __init trusted_shash_alloc(void)
1144 {
1145         int ret;
1146
1147         hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
1148         if (IS_ERR(hmacalg)) {
1149                 pr_info("trusted_key: could not allocate crypto %s\n",
1150                         hmac_alg);
1151                 return PTR_ERR(hmacalg);
1152         }
1153
1154         hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
1155         if (IS_ERR(hashalg)) {
1156                 pr_info("trusted_key: could not allocate crypto %s\n",
1157                         hash_alg);
1158                 ret = PTR_ERR(hashalg);
1159                 goto hashalg_fail;
1160         }
1161
1162         return 0;
1163
1164 hashalg_fail:
1165         crypto_free_shash(hmacalg);
1166         return ret;
1167 }
1168
1169 static int __init init_trusted(void)
1170 {
1171         int ret;
1172
1173         ret = trusted_shash_alloc();
1174         if (ret < 0)
1175                 return ret;
1176         ret = register_key_type(&key_type_trusted);
1177         if (ret < 0)
1178                 trusted_shash_release();
1179         return ret;
1180 }
1181
1182 static void __exit cleanup_trusted(void)
1183 {
1184         trusted_shash_release();
1185         unregister_key_type(&key_type_trusted);
1186 }
1187
1188 late_initcall(init_trusted);
1189 module_exit(cleanup_trusted);
1190
1191 MODULE_LICENSE("GPL");