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  * Lock a trusted key, by extending a selected PCR.
 373  *
 374  * Prevents a trusted key that is sealed to PCRs from being accessed.
 375  * This uses the tpm driver's extend function.
 376  */
 377 static int pcrlock(const int pcrnum)
 378 {
 379         unsigned char hash[SHA1_DIGEST_SIZE];
 380         int ret;
 381
 382         if (!capable(CAP_SYS_ADMIN))
 383                 return -EPERM;
 384         ret = tpm_get_random(TPM_ANY_NUM, hash, SHA1_DIGEST_SIZE);
 385         if (ret != SHA1_DIGEST_SIZE)
 386                 return ret;
 387         return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
 388 }
 389
 390 /*
 391  * Create an object specific authorisation protocol (OSAP) session
 392  */
 393 static int osap(struct tpm_buf *tb, struct osapsess *s,
 394                 const unsigned char *key, uint16_t type, uint32_t handle)
 395 {
 396         unsigned char enonce[TPM_NONCE_SIZE];
 397         unsigned char ononce[TPM_NONCE_SIZE];
 398         int ret;
 399
 400         ret = tpm_get_random(TPM_ANY_NUM, ononce, TPM_NONCE_SIZE);
 401         if (ret != TPM_NONCE_SIZE)
 402                 return ret;
 403
 404         INIT_BUF(tb);
 405         store16(tb, TPM_TAG_RQU_COMMAND);
 406         store32(tb, TPM_OSAP_SIZE);
 407         store32(tb, TPM_ORD_OSAP);
 408         store16(tb, type);
 409         store32(tb, handle);
 410         storebytes(tb, ononce, TPM_NONCE_SIZE);
 411
 412         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
 413         if (ret < 0)
 414                 return ret;
 415
 416         s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
 417         memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
 418                TPM_NONCE_SIZE);
 419         memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
 420                                   TPM_NONCE_SIZE]), TPM_NONCE_SIZE);
 421         return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
 422                            enonce, TPM_NONCE_SIZE, ononce, 0, 0);
 423 }
 424
 425 /*
 426  * Create an object independent authorisation protocol (oiap) session
 427  */
 428 static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
 429 {
 430         int ret;
 431
 432         INIT_BUF(tb);
 433         store16(tb, TPM_TAG_RQU_COMMAND);
 434         store32(tb, TPM_OIAP_SIZE);
 435         store32(tb, TPM_ORD_OIAP);
 436         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
 437         if (ret < 0)
 438                 return ret;
 439
 440         *handle = LOAD32(tb->data, TPM_DATA_OFFSET);
 441         memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
 442                TPM_NONCE_SIZE);
 443         return 0;
 444 }
 445
 446 struct tpm_digests {
 447         unsigned char encauth[SHA1_DIGEST_SIZE];
 448         unsigned char pubauth[SHA1_DIGEST_SIZE];
 449         unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
 450         unsigned char xorhash[SHA1_DIGEST_SIZE];
 451         unsigned char nonceodd[TPM_NONCE_SIZE];
 452 };
 453
 454 /*
 455  * Have the TPM seal(encrypt) the trusted key, possibly based on
 456  * Platform Configuration Registers (PCRs). AUTH1 for sealing key.
 457  */
 458 static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
 459                     uint32_t keyhandle, const unsigned char *keyauth,
 460                     const unsigned char *data, uint32_t datalen,
 461                     unsigned char *blob, uint32_t *bloblen,
 462                     const unsigned char *blobauth,
 463                     const unsigned char *pcrinfo, uint32_t pcrinfosize)
 464 {
 465         struct osapsess sess;
 466         struct tpm_digests *td;
 467         unsigned char cont;
 468         uint32_t ordinal;
 469         uint32_t pcrsize;
 470         uint32_t datsize;
 471         int sealinfosize;
 472         int encdatasize;
 473         int storedsize;
 474         int ret;
 475         int i;
 476
 477         /* alloc some work space for all the hashes */
 478         td = kmalloc(sizeof *td, GFP_KERNEL);
 479         if (!td)
 480                 return -ENOMEM;
 481
 482         /* get session for sealing key */
 483         ret = osap(tb, &sess, keyauth, keytype, keyhandle);
 484         if (ret < 0)
 485                 goto out;
 486         dump_sess(&sess);
 487
 488         /* calculate encrypted authorization value */
 489         memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
 490         memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
 491         ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
 492         if (ret < 0)
 493                 goto out;
 494
 495         ret = tpm_get_random(TPM_ANY_NUM, td->nonceodd, TPM_NONCE_SIZE);
 496         if (ret != TPM_NONCE_SIZE)
 497                 goto out;
 498         ordinal = htonl(TPM_ORD_SEAL);
 499         datsize = htonl(datalen);
 500         pcrsize = htonl(pcrinfosize);
 501         cont = 0;
 502
 503         /* encrypt data authorization key */
 504         for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
 505                 td->encauth[i] = td->xorhash[i] ^ blobauth[i];
 506
 507         /* calculate authorization HMAC value */
 508         if (pcrinfosize == 0) {
 509                 /* no pcr info specified */
 510                 ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
 511                                    sess.enonce, td->nonceodd, cont,
 512                                    sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
 513                                    td->encauth, sizeof(uint32_t), &pcrsize,
 514                                    sizeof(uint32_t), &datsize, datalen, data, 0,
 515                                    0);
 516         } else {
 517                 /* pcr info specified */
 518                 ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
 519                                    sess.enonce, td->nonceodd, cont,
 520                                    sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
 521                                    td->encauth, sizeof(uint32_t), &pcrsize,
 522                                    pcrinfosize, pcrinfo, sizeof(uint32_t),
 523                                    &datsize, datalen, data, 0, 0);
 524         }
 525         if (ret < 0)
 526                 goto out;
 527
 528         /* build and send the TPM request packet */
 529         INIT_BUF(tb);
 530         store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
 531         store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen);
 532         store32(tb, TPM_ORD_SEAL);
 533         store32(tb, keyhandle);
 534         storebytes(tb, td->encauth, SHA1_DIGEST_SIZE);
 535         store32(tb, pcrinfosize);
 536         storebytes(tb, pcrinfo, pcrinfosize);
 537         store32(tb, datalen);
 538         storebytes(tb, data, datalen);
 539         store32(tb, sess.handle);
 540         storebytes(tb, td->nonceodd, TPM_NONCE_SIZE);
 541         store8(tb, cont);
 542         storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
 543
 544         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
 545         if (ret < 0)
 546                 goto out;
 547
 548         /* calculate the size of the returned Blob */
 549         sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t));
 550         encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) +
 551                              sizeof(uint32_t) + sealinfosize);
 552         storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize +
 553             sizeof(uint32_t) + encdatasize;
 554
 555         /* check the HMAC in the response */
 556         ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret,
 557                              SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0,
 558                              0);
 559
 560         /* copy the returned blob to caller */
 561         if (!ret) {
 562                 memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
 563                 *bloblen = storedsize;
 564         }
 565 out:
 566         kfree(td);
 567         return ret;
 568 }
 569
 570 /*
 571  * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
 572  */
 573 static int tpm_unseal(struct tpm_buf *tb,
 574                       uint32_t keyhandle, const unsigned char *keyauth,
 575                       const unsigned char *blob, int bloblen,
 576                       const unsigned char *blobauth,
 577                       unsigned char *data, unsigned int *datalen)
 578 {
 579         unsigned char nonceodd[TPM_NONCE_SIZE];
 580         unsigned char enonce1[TPM_NONCE_SIZE];
 581         unsigned char enonce2[TPM_NONCE_SIZE];
 582         unsigned char authdata1[SHA1_DIGEST_SIZE];
 583         unsigned char authdata2[SHA1_DIGEST_SIZE];
 584         uint32_t authhandle1 = 0;
 585         uint32_t authhandle2 = 0;
 586         unsigned char cont = 0;
 587         uint32_t ordinal;
 588         uint32_t keyhndl;
 589         int ret;
 590
 591         /* sessions for unsealing key and data */
 592         ret = oiap(tb, &authhandle1, enonce1);
 593         if (ret < 0) {
 594                 pr_info("trusted_key: oiap failed (%d)\n", ret);
 595                 return ret;
 596         }
 597         ret = oiap(tb, &authhandle2, enonce2);
 598         if (ret < 0) {
 599                 pr_info("trusted_key: oiap failed (%d)\n", ret);
 600                 return ret;
 601         }
 602
 603         ordinal = htonl(TPM_ORD_UNSEAL);
 604         keyhndl = htonl(SRKHANDLE);
 605         ret = tpm_get_random(TPM_ANY_NUM, nonceodd, TPM_NONCE_SIZE);
 606         if (ret != TPM_NONCE_SIZE) {
 607                 pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
 608                 return ret;
 609         }
 610         ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
 611                            enonce1, nonceodd, cont, sizeof(uint32_t),
 612                            &ordinal, bloblen, blob, 0, 0);
 613         if (ret < 0)
 614                 return ret;
 615         ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
 616                            enonce2, nonceodd, cont, sizeof(uint32_t),
 617                            &ordinal, bloblen, blob, 0, 0);
 618         if (ret < 0)
 619                 return ret;
 620
 621         /* build and send TPM request packet */
 622         INIT_BUF(tb);
 623         store16(tb, TPM_TAG_RQU_AUTH2_COMMAND);
 624         store32(tb, TPM_UNSEAL_SIZE + bloblen);
 625         store32(tb, TPM_ORD_UNSEAL);
 626         store32(tb, keyhandle);
 627         storebytes(tb, blob, bloblen);
 628         store32(tb, authhandle1);
 629         storebytes(tb, nonceodd, TPM_NONCE_SIZE);
 630         store8(tb, cont);
 631         storebytes(tb, authdata1, SHA1_DIGEST_SIZE);
 632         store32(tb, authhandle2);
 633         storebytes(tb, nonceodd, TPM_NONCE_SIZE);
 634         store8(tb, cont);
 635         storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
 636
 637         ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
 638         if (ret < 0) {
 639                 pr_info("trusted_key: authhmac failed (%d)\n", ret);
 640                 return ret;
 641         }
 642
 643         *datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
 644         ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
 645                              keyauth, SHA1_DIGEST_SIZE,
 646                              blobauth, SHA1_DIGEST_SIZE,
 647                              sizeof(uint32_t), TPM_DATA_OFFSET,
 648                              *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
 649                              0);
 650         if (ret < 0) {
 651                 pr_info("trusted_key: TSS_checkhmac2 failed (%d)\n", ret);
 652                 return ret;
 653         }
 654         memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);
 655         return 0;
 656 }
 657
 658 /*
 659  * Have the TPM seal(encrypt) the symmetric key
 660  */
 661 static int key_seal(struct trusted_key_payload *p,
 662                     struct trusted_key_options *o)
 663 {
 664         struct tpm_buf *tb;
 665         int ret;
 666
 667         tb = kzalloc(sizeof *tb, GFP_KERNEL);
 668         if (!tb)
 669                 return -ENOMEM;
 670
 671         /* include migratable flag at end of sealed key */
 672         p->key[p->key_len] = p->migratable;
 673
 674         ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
 675                        p->key, p->key_len + 1, p->blob, &p->blob_len,
 676                        o->blobauth, o->pcrinfo, o->pcrinfo_len);
 677         if (ret < 0)
 678                 pr_info("trusted_key: srkseal failed (%d)\n", ret);
 679
 680         kfree(tb);
 681         return ret;
 682 }
 683
 684 /*
 685  * Have the TPM unseal(decrypt) the symmetric key
 686  */
 687 static int key_unseal(struct trusted_key_payload *p,
 688                       struct trusted_key_options *o)
 689 {
 690         struct tpm_buf *tb;
 691         int ret;
 692
 693         tb = kzalloc(sizeof *tb, GFP_KERNEL);
 694         if (!tb)
 695                 return -ENOMEM;
 696
 697         ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
 698                          o->blobauth, p->key, &p->key_len);
 699         if (ret < 0)
 700                 pr_info("trusted_key: srkunseal failed (%d)\n", ret);
 701         else
 702                 /* pull migratable flag out of sealed key */
 703                 p->migratable = p->key[--p->key_len];
 704
 705         kfree(tb);
 706         return ret;
 707 }
 708
 709 enum {
 710         Opt_err = -1,
 711         Opt_new, Opt_load, Opt_update,
 712         Opt_keyhandle, Opt_keyauth, Opt_blobauth,
 713         Opt_pcrinfo, Opt_pcrlock, Opt_migratable
 714 };
 715
 716 static const match_table_t key_tokens = {
 717         {Opt_new, "new"},
 718         {Opt_load, "load"},
 719         {Opt_update, "update"},
 720         {Opt_keyhandle, "keyhandle=%s"},
 721         {Opt_keyauth, "keyauth=%s"},
 722         {Opt_blobauth, "blobauth=%s"},
 723         {Opt_pcrinfo, "pcrinfo=%s"},
 724         {Opt_pcrlock, "pcrlock=%s"},
 725         {Opt_migratable, "migratable=%s"},
 726         {Opt_err, NULL}
 727 };
 728
 729 /* can have zero or more token= options */
 730 static int getoptions(char *c, struct trusted_key_payload *pay,
 731                       struct trusted_key_options *opt)
 732 {
 733         substring_t args[MAX_OPT_ARGS];
 734         char *p = c;
 735         int token;
 736         int res;
 737         unsigned long handle;
 738         unsigned long lock;
 739
 740         while ((p = strsep(&c, " \t"))) {
 741                 if (*p == '\0' || *p == ' ' || *p == '\t')
 742                         continue;
 743                 token = match_token(p, key_tokens, args);
 744
 745                 switch (token) {
 746                 case Opt_pcrinfo:
 747                         opt->pcrinfo_len = strlen(args[0].from) / 2;
 748                         if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
 749                                 return -EINVAL;
 750                         res = hex2bin(opt->pcrinfo, args[0].from,
 751                                       opt->pcrinfo_len);
 752                         if (res < 0)
 753                                 return -EINVAL;
 754                         break;
 755                 case Opt_keyhandle:
 756                         res = kstrtoul(args[0].from, 16, &handle);
 757                         if (res < 0)
 758                                 return -EINVAL;
 759                         opt->keytype = SEAL_keytype;
 760                         opt->keyhandle = handle;
 761                         break;
 762                 case Opt_keyauth:
 763                         if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
 764                                 return -EINVAL;
 765                         res = hex2bin(opt->keyauth, args[0].from,
 766                                       SHA1_DIGEST_SIZE);
 767                         if (res < 0)
 768                                 return -EINVAL;
 769                         break;
 770                 case Opt_blobauth:
 771                         if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
 772                                 return -EINVAL;
 773                         res = hex2bin(opt->blobauth, args[0].from,
 774                                       SHA1_DIGEST_SIZE);
 775                         if (res < 0)
 776                                 return -EINVAL;
 777                         break;
 778                 case Opt_migratable:
 779                         if (*args[0].from == '0')
 780                                 pay->migratable = 0;
 781                         else
 782                                 return -EINVAL;
 783                         break;
 784                 case Opt_pcrlock:
 785                         res = kstrtoul(args[0].from, 10, &lock);
 786                         if (res < 0)
 787                                 return -EINVAL;
 788                         opt->pcrlock = lock;
 789                         break;
 790                 default:
 791                         return -EINVAL;
 792                 }
 793         }
 794         return 0;
 795 }
 796
 797 /*
 798  * datablob_parse - parse the keyctl data and fill in the
 799  *                  payload and options structures
 800  *
 801  * On success returns 0, otherwise -EINVAL.
 802  */
 803 static int datablob_parse(char *datablob, struct trusted_key_payload *p,
 804                           struct trusted_key_options *o)
 805 {
 806         substring_t args[MAX_OPT_ARGS];
 807         long keylen;
 808         int ret = -EINVAL;
 809         int key_cmd;
 810         char *c;
 811
 812         /* main command */
 813         c = strsep(&datablob, " \t");
 814         if (!c)
 815                 return -EINVAL;
 816         key_cmd = match_token(c, key_tokens, args);
 817         switch (key_cmd) {
 818         case Opt_new:
 819                 /* first argument is key size */
 820                 c = strsep(&datablob, " \t");
 821                 if (!c)
 822                         return -EINVAL;
 823                 ret = kstrtol(c, 10, &keylen);
 824                 if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
 825                         return -EINVAL;
 826                 p->key_len = keylen;
 827                 ret = getoptions(datablob, p, o);
 828                 if (ret < 0)
 829                         return ret;
 830                 ret = Opt_new;
 831                 break;
 832         case Opt_load:
 833                 /* first argument is sealed blob */
 834                 c = strsep(&datablob, " \t");
 835                 if (!c)
 836                         return -EINVAL;
 837                 p->blob_len = strlen(c) / 2;
 838                 if (p->blob_len > MAX_BLOB_SIZE)
 839                         return -EINVAL;
 840                 ret = hex2bin(p->blob, c, p->blob_len);
 841                 if (ret < 0)
 842                         return -EINVAL;
 843                 ret = getoptions(datablob, p, o);
 844                 if (ret < 0)
 845                         return ret;
 846                 ret = Opt_load;
 847                 break;
 848         case Opt_update:
 849                 /* all arguments are options */
 850                 ret = getoptions(datablob, p, o);
 851                 if (ret < 0)
 852                         return ret;
 853                 ret = Opt_update;
 854                 break;
 855         case Opt_err:
 856                 return -EINVAL;
 857                 break;
 858         }
 859         return ret;
 860 }
 861
 862 static struct trusted_key_options *trusted_options_alloc(void)
 863 {
 864         struct trusted_key_options *options;
 865         int tpm2;
 866
 867         tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
 868         if (tpm2 < 0)
 869                 return NULL;
 870
 871         options = kzalloc(sizeof *options, GFP_KERNEL);
 872         if (options) {
 873                 /* set any non-zero defaults */
 874                 options->keytype = SRK_keytype;
 875
 876                 if (!tpm2)
 877                         options->keyhandle = SRKHANDLE;
 878         }
 879         return options;
 880 }
 881
 882 static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
 883 {
 884         struct trusted_key_payload *p = NULL;
 885         int ret;
 886
 887         ret = key_payload_reserve(key, sizeof *p);
 888         if (ret < 0)
 889                 return p;
 890         p = kzalloc(sizeof *p, GFP_KERNEL);
 891         if (p)
 892                 p->migratable = 1; /* migratable by default */
 893         return p;
 894 }
 895
 896 /*
 897  * trusted_instantiate - create a new trusted key
 898  *
 899  * Unseal an existing trusted blob or, for a new key, get a
 900  * random key, then seal and create a trusted key-type key,
 901  * adding it to the specified keyring.
 902  *
 903  * On success, return 0. Otherwise return errno.
 904  */
 905 static int trusted_instantiate(struct key *key,
 906                                struct key_preparsed_payload *prep)
 907 {
 908         struct trusted_key_payload *payload = NULL;
 909         struct trusted_key_options *options = NULL;
 910         size_t datalen = prep->datalen;
 911         char *datablob;
 912         int ret = 0;
 913         int key_cmd;
 914         size_t key_len;
 915         int tpm2;
 916
 917         tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
 918         if (tpm2 < 0)
 919                 return tpm2;
 920
 921         if (datalen <= 0 || datalen > 32767 || !prep->data)
 922                 return -EINVAL;
 923
 924         datablob = kmalloc(datalen + 1, GFP_KERNEL);
 925         if (!datablob)
 926                 return -ENOMEM;
 927         memcpy(datablob, prep->data, datalen);
 928         datablob[datalen] = '\0';
 929
 930         options = trusted_options_alloc();
 931         if (!options) {
 932                 ret = -ENOMEM;
 933                 goto out;
 934         }
 935         payload = trusted_payload_alloc(key);
 936         if (!payload) {
 937                 ret = -ENOMEM;
 938                 goto out;
 939         }
 940
 941         key_cmd = datablob_parse(datablob, payload, options);
 942         if (key_cmd < 0) {
 943                 ret = key_cmd;
 944                 goto out;
 945         }
 946
 947         if (!options->keyhandle) {
 948                 ret = -EINVAL;
 949                 goto out;
 950         }
 951
 952         dump_payload(payload);
 953         dump_options(options);
 954
 955         switch (key_cmd) {
 956         case Opt_load:
 957                 if (tpm2)
 958                         ret = tpm_unseal_trusted(TPM_ANY_NUM, payload, options);
 959                 else
 960                         ret = key_unseal(payload, options);
 961                 dump_payload(payload);
 962                 dump_options(options);
 963                 if (ret < 0)
 964                         pr_info("trusted_key: key_unseal failed (%d)\n", ret);
 965                 break;
 966         case Opt_new:
 967                 key_len = payload->key_len;
 968                 ret = tpm_get_random(TPM_ANY_NUM, payload->key, key_len);
 969                 if (ret != key_len) {
 970                         pr_info("trusted_key: key_create failed (%d)\n", ret);
 971                         goto out;
 972                 }
 973                 if (tpm2)
 974                         ret = tpm_seal_trusted(TPM_ANY_NUM, payload, options);
 975                 else
 976                         ret = key_seal(payload, options);
 977                 if (ret < 0)
 978                         pr_info("trusted_key: key_seal failed (%d)\n", ret);
 979                 break;
 980         default:
 981                 ret = -EINVAL;
 982                 goto out;
 983         }
 984         if (!ret && options->pcrlock)
 985                 ret = pcrlock(options->pcrlock);
 986 out:
 987         kfree(datablob);
 988         kfree(options);
 989         if (!ret)
 990                 rcu_assign_keypointer(key, payload);
 991         else
 992                 kfree(payload);
 993         return ret;
 994 }
 995
 996 static void trusted_rcu_free(struct rcu_head *rcu)
 997 {
 998         struct trusted_key_payload *p;
 999
1000         p = container_of(rcu, struct trusted_key_payload, rcu);
1001         memset(p->key, 0, p->key_len);
1002         kfree(p);
1003 }
1004
1005 /*
1006  * trusted_update - reseal an existing key with new PCR values
1007  */
1008 static int trusted_update(struct key *key, struct key_preparsed_payload *prep)
1009 {
1010         struct trusted_key_payload *p;
1011         struct trusted_key_payload *new_p;
1012         struct trusted_key_options *new_o;
1013         size_t datalen = prep->datalen;
1014         char *datablob;
1015         int ret = 0;
1016
1017         if (test_bit(KEY_FLAG_NEGATIVE, &key->flags))
1018                 return -ENOKEY;
1019         p = key->payload.data[0];
1020         if (!p->migratable)
1021                 return -EPERM;
1022         if (datalen <= 0 || datalen > 32767 || !prep->data)
1023                 return -EINVAL;
1024
1025         datablob = kmalloc(datalen + 1, GFP_KERNEL);
1026         if (!datablob)
1027                 return -ENOMEM;
1028         new_o = trusted_options_alloc();
1029         if (!new_o) {
1030                 ret = -ENOMEM;
1031                 goto out;
1032         }
1033         new_p = trusted_payload_alloc(key);
1034         if (!new_p) {
1035                 ret = -ENOMEM;
1036                 goto out;
1037         }
1038
1039         memcpy(datablob, prep->data, datalen);
1040         datablob[datalen] = '\0';
1041         ret = datablob_parse(datablob, new_p, new_o);
1042         if (ret != Opt_update) {
1043                 ret = -EINVAL;
1044                 kfree(new_p);
1045                 goto out;
1046         }
1047
1048         if (!new_o->keyhandle) {
1049                 ret = -EINVAL;
1050                 kfree(new_p);
1051                 goto out;
1052         }
1053
1054         /* copy old key values, and reseal with new pcrs */
1055         new_p->migratable = p->migratable;
1056         new_p->key_len = p->key_len;
1057         memcpy(new_p->key, p->key, p->key_len);
1058         dump_payload(p);
1059         dump_payload(new_p);
1060
1061         ret = key_seal(new_p, new_o);
1062         if (ret < 0) {
1063                 pr_info("trusted_key: key_seal failed (%d)\n", ret);
1064                 kfree(new_p);
1065                 goto out;
1066         }
1067         if (new_o->pcrlock) {
1068                 ret = pcrlock(new_o->pcrlock);
1069                 if (ret < 0) {
1070                         pr_info("trusted_key: pcrlock failed (%d)\n", ret);
1071                         kfree(new_p);
1072                         goto out;
1073                 }
1074         }
1075         rcu_assign_keypointer(key, new_p);
1076         call_rcu(&p->rcu, trusted_rcu_free);
1077 out:
1078         kfree(datablob);
1079         kfree(new_o);
1080         return ret;
1081 }
1082
1083 /*
1084  * trusted_read - copy the sealed blob data to userspace in hex.
1085  * On success, return to userspace the trusted key datablob size.
1086  */
1087 static long trusted_read(const struct key *key, char __user *buffer,
1088                          size_t buflen)
1089 {
1090         struct trusted_key_payload *p;
1091         char *ascii_buf;
1092         char *bufp;
1093         int i;
1094
1095         p = rcu_dereference_key(key);
1096         if (!p)
1097                 return -EINVAL;
1098         if (!buffer || buflen <= 0)
1099                 return 2 * p->blob_len;
1100         ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
1101         if (!ascii_buf)
1102                 return -ENOMEM;
1103
1104         bufp = ascii_buf;
1105         for (i = 0; i < p->blob_len; i++)
1106                 bufp = hex_byte_pack(bufp, p->blob[i]);
1107         if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
1108                 kfree(ascii_buf);
1109                 return -EFAULT;
1110         }
1111         kfree(ascii_buf);
1112         return 2 * p->blob_len;
1113 }
1114
1115 /*
1116  * trusted_destroy - before freeing the key, clear the decrypted data
1117  */
1118 static void trusted_destroy(struct key *key)
1119 {
1120         struct trusted_key_payload *p = key->payload.data[0];
1121
1122         if (!p)
1123                 return;
1124         memset(p->key, 0, p->key_len);
1125         kfree(key->payload.data[0]);
1126 }
1127
1128 struct key_type key_type_trusted = {
1129         .name = "trusted",
1130         .instantiate = trusted_instantiate,
1131         .update = trusted_update,
1132         .destroy = trusted_destroy,
1133         .describe = user_describe,
1134         .read = trusted_read,
1135 };
1136
1137 EXPORT_SYMBOL_GPL(key_type_trusted);
1138
1139 static void trusted_shash_release(void)
1140 {
1141         if (hashalg)
1142                 crypto_free_shash(hashalg);
1143         if (hmacalg)
1144                 crypto_free_shash(hmacalg);
1145 }
1146
1147 static int __init trusted_shash_alloc(void)
1148 {
1149         int ret;
1150
1151         hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
1152         if (IS_ERR(hmacalg)) {
1153                 pr_info("trusted_key: could not allocate crypto %s\n",
1154                         hmac_alg);
1155                 return PTR_ERR(hmacalg);
1156         }
1157
1158         hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
1159         if (IS_ERR(hashalg)) {
1160                 pr_info("trusted_key: could not allocate crypto %s\n",
1161                         hash_alg);
1162                 ret = PTR_ERR(hashalg);
1163                 goto hashalg_fail;
1164         }
1165
1166         return 0;
1167
1168 hashalg_fail:
1169         crypto_free_shash(hmacalg);
1170         return ret;
1171 }
1172
1173 static int __init init_trusted(void)
1174 {
1175         int ret;
1176
1177         ret = trusted_shash_alloc();
1178         if (ret < 0)
1179                 return ret;
1180         ret = register_key_type(&key_type_trusted);
1181         if (ret < 0)
1182                 trusted_shash_release();
1183         return ret;
1184 }
1185
1186 static void __exit cleanup_trusted(void)
1187 {
1188         trusted_shash_release();
1189         unregister_key_type(&key_type_trusted);
1190 }
1191
1192 late_initcall(init_trusted);
1193 module_exit(cleanup_trusted);
1194
1195 MODULE_LICENSE("GPL");