fs/ecryptfs/keystore.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  * In-kernel key management code.  Includes functions to parse and
   4  * write authentication token-related packets with the underlying
   5  * file.
   6  *
   7  * Copyright (C) 2004-2006 International Business Machines Corp.
   8  *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
   9  *              Michael C. Thompson <mcthomps@us.ibm.com>
  10  *              Trevor S. Highland <trevor.highland@gmail.com>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  25  * 02111-1307, USA.
  26  */
  27
  28 #include <linux/string.h>
  29 #include <linux/pagemap.h>
  30 #include <linux/key.h>
  31 #include <linux/random.h>
  32 #include <linux/crypto.h>
  33 #include <linux/scatterlist.h>
  34 #include <linux/slab.h>
  35 #include "ecryptfs_kernel.h"
  36
  37 /**
  38  * request_key returned an error instead of a valid key address;
  39  * determine the type of error, make appropriate log entries, and
  40  * return an error code.
  41  */
  42 static int process_request_key_err(long err_code)
  43 {
  44         int rc = 0;
  45
  46         switch (err_code) {
  47         case -ENOKEY:
  48                 ecryptfs_printk(KERN_WARNING, "No key\n");
  49                 rc = -ENOENT;
  50                 break;
  51         case -EKEYEXPIRED:
  52                 ecryptfs_printk(KERN_WARNING, "Key expired\n");
  53                 rc = -ETIME;
  54                 break;
  55         case -EKEYREVOKED:
  56                 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
  57                 rc = -EINVAL;
  58                 break;
  59         default:
  60                 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
  61                                 "[0x%.16lx]\n", err_code);
  62                 rc = -EINVAL;
  63         }
  64         return rc;
  65 }
  66
  67 static int process_find_global_auth_tok_for_sig_err(int err_code)
  68 {
  69         int rc = err_code;
  70
  71         switch (err_code) {
  72         case -ENOENT:
  73                 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
  74                 break;
  75         case -EINVAL:
  76                 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
  77                 break;
  78         default:
  79                 rc = process_request_key_err(err_code);
  80                 break;
  81         }
  82         return rc;
  83 }
  84
  85 /**
  86  * ecryptfs_parse_packet_length
  87  * @data: Pointer to memory containing length at offset
  88  * @size: This function writes the decoded size to this memory
  89  *        address; zero on error
  90  * @length_size: The number of bytes occupied by the encoded length
  91  *
  92  * Returns zero on success; non-zero on error
  93  */
  94 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
  95                                  size_t *length_size)
  96 {
  97         int rc = 0;
  98
  99         (*length_size) = 0;
 100         (*size) = 0;
 101         if (data[0] < 192) {
 102                 /* One-byte length */
 103                 (*size) = data[0];
 104                 (*length_size) = 1;
 105         } else if (data[0] < 224) {
 106                 /* Two-byte length */
 107                 (*size) = (data[0] - 192) * 256;
 108                 (*size) += data[1] + 192;
 109                 (*length_size) = 2;
 110         } else if (data[0] == 255) {
 111                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
 112                 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
 113                                 "supported\n");
 114                 rc = -EINVAL;
 115                 goto out;
 116         } else {
 117                 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
 118                 rc = -EINVAL;
 119                 goto out;
 120         }
 121 out:
 122         return rc;
 123 }
 124
 125 /**
 126  * ecryptfs_write_packet_length
 127  * @dest: The byte array target into which to write the length. Must
 128  *        have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
 129  * @size: The length to write.
 130  * @packet_size_length: The number of bytes used to encode the packet
 131  *                      length is written to this address.
 132  *
 133  * Returns zero on success; non-zero on error.
 134  */
 135 int ecryptfs_write_packet_length(char *dest, size_t size,
 136                                  size_t *packet_size_length)
 137 {
 138         int rc = 0;
 139
 140         if (size < 192) {
 141                 dest[0] = size;
 142                 (*packet_size_length) = 1;
 143         } else if (size < 65536) {
 144                 dest[0] = (((size - 192) / 256) + 192);
 145                 dest[1] = ((size - 192) % 256);
 146                 (*packet_size_length) = 2;
 147         } else {
 148                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
 149                 rc = -EINVAL;
 150                 ecryptfs_printk(KERN_WARNING,
 151                                 "Unsupported packet size: [%zd]\n", size);
 152         }
 153         return rc;
 154 }
 155
 156 static int
 157 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
 158                     char **packet, size_t *packet_len)
 159 {
 160         size_t i = 0;
 161         size_t data_len;
 162         size_t packet_size_len;
 163         char *message;
 164         int rc;
 165
 166         /*
 167          *              ***** TAG 64 Packet Format *****
 168          *    | Content Type                       | 1 byte       |
 169          *    | Key Identifier Size                | 1 or 2 bytes |
 170          *    | Key Identifier                     | arbitrary    |
 171          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 172          *    | Encrypted File Encryption Key      | arbitrary    |
 173          */
 174         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
 175                     + session_key->encrypted_key_size);
 176         *packet = kmalloc(data_len, GFP_KERNEL);
 177         message = *packet;
 178         if (!message) {
 179                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 180                 rc = -ENOMEM;
 181                 goto out;
 182         }
 183         message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
 184         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 185                                           &packet_size_len);
 186         if (rc) {
 187                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 188                                 "header; cannot generate packet length\n");
 189                 goto out;
 190         }
 191         i += packet_size_len;
 192         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 193         i += ECRYPTFS_SIG_SIZE_HEX;
 194         rc = ecryptfs_write_packet_length(&message[i],
 195                                           session_key->encrypted_key_size,
 196                                           &packet_size_len);
 197         if (rc) {
 198                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 199                                 "header; cannot generate packet length\n");
 200                 goto out;
 201         }
 202         i += packet_size_len;
 203         memcpy(&message[i], session_key->encrypted_key,
 204                session_key->encrypted_key_size);
 205         i += session_key->encrypted_key_size;
 206         *packet_len = i;
 207 out:
 208         return rc;
 209 }
 210
 211 static int
 212 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
 213                     struct ecryptfs_message *msg)
 214 {
 215         size_t i = 0;
 216         char *data;
 217         size_t data_len;
 218         size_t m_size;
 219         size_t message_len;
 220         u16 checksum = 0;
 221         u16 expected_checksum = 0;
 222         int rc;
 223
 224         /*
 225          *              ***** TAG 65 Packet Format *****
 226          *         | Content Type             | 1 byte       |
 227          *         | Status Indicator         | 1 byte       |
 228          *         | File Encryption Key Size | 1 or 2 bytes |
 229          *         | File Encryption Key      | arbitrary    |
 230          */
 231         message_len = msg->data_len;
 232         data = msg->data;
 233         if (message_len < 4) {
 234                 rc = -EIO;
 235                 goto out;
 236         }
 237         if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
 238                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
 239                 rc = -EIO;
 240                 goto out;
 241         }
 242         if (data[i++]) {
 243                 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
 244                                 "[%d]\n", data[i-1]);
 245                 rc = -EIO;
 246                 goto out;
 247         }
 248         rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
 249         if (rc) {
 250                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 251                                 "rc = [%d]\n", rc);
 252                 goto out;
 253         }
 254         i += data_len;
 255         if (message_len < (i + m_size)) {
 256                 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
 257                                 "is shorter than expected\n");
 258                 rc = -EIO;
 259                 goto out;
 260         }
 261         if (m_size < 3) {
 262                 ecryptfs_printk(KERN_ERR,
 263                                 "The decrypted key is not long enough to "
 264                                 "include a cipher code and checksum\n");
 265                 rc = -EIO;
 266                 goto out;
 267         }
 268         *cipher_code = data[i++];
 269         /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
 270         session_key->decrypted_key_size = m_size - 3;
 271         if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
 272                 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
 273                                 "the maximum key size [%d]\n",
 274                                 session_key->decrypted_key_size,
 275                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 276                 rc = -EIO;
 277                 goto out;
 278         }
 279         memcpy(session_key->decrypted_key, &data[i],
 280                session_key->decrypted_key_size);
 281         i += session_key->decrypted_key_size;
 282         expected_checksum += (unsigned char)(data[i++]) << 8;
 283         expected_checksum += (unsigned char)(data[i++]);
 284         for (i = 0; i < session_key->decrypted_key_size; i++)
 285                 checksum += session_key->decrypted_key[i];
 286         if (expected_checksum != checksum) {
 287                 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
 288                                 "encryption  key; expected [%x]; calculated "
 289                                 "[%x]\n", expected_checksum, checksum);
 290                 rc = -EIO;
 291         }
 292 out:
 293         return rc;
 294 }
 295
 296
 297 static int
 298 write_tag_66_packet(char *signature, u8 cipher_code,
 299                     struct ecryptfs_crypt_stat *crypt_stat, char **packet,
 300                     size_t *packet_len)
 301 {
 302         size_t i = 0;
 303         size_t j;
 304         size_t data_len;
 305         size_t checksum = 0;
 306         size_t packet_size_len;
 307         char *message;
 308         int rc;
 309
 310         /*
 311          *              ***** TAG 66 Packet Format *****
 312          *         | Content Type             | 1 byte       |
 313          *         | Key Identifier Size      | 1 or 2 bytes |
 314          *         | Key Identifier           | arbitrary    |
 315          *         | File Encryption Key Size | 1 or 2 bytes |
 316          *         | File Encryption Key      | arbitrary    |
 317          */
 318         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
 319         *packet = kmalloc(data_len, GFP_KERNEL);
 320         message = *packet;
 321         if (!message) {
 322                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 323                 rc = -ENOMEM;
 324                 goto out;
 325         }
 326         message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
 327         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 328                                           &packet_size_len);
 329         if (rc) {
 330                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 331                                 "header; cannot generate packet length\n");
 332                 goto out;
 333         }
 334         i += packet_size_len;
 335         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 336         i += ECRYPTFS_SIG_SIZE_HEX;
 337         /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
 338         rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
 339                                           &packet_size_len);
 340         if (rc) {
 341                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 342                                 "header; cannot generate packet length\n");
 343                 goto out;
 344         }
 345         i += packet_size_len;
 346         message[i++] = cipher_code;
 347         memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
 348         i += crypt_stat->key_size;
 349         for (j = 0; j < crypt_stat->key_size; j++)
 350                 checksum += crypt_stat->key[j];
 351         message[i++] = (checksum / 256) % 256;
 352         message[i++] = (checksum % 256);
 353         *packet_len = i;
 354 out:
 355         return rc;
 356 }
 357
 358 static int
 359 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
 360                     struct ecryptfs_message *msg)
 361 {
 362         size_t i = 0;
 363         char *data;
 364         size_t data_len;
 365         size_t message_len;
 366         int rc;
 367
 368         /*
 369          *              ***** TAG 65 Packet Format *****
 370          *    | Content Type                       | 1 byte       |
 371          *    | Status Indicator                   | 1 byte       |
 372          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 373          *    | Encrypted File Encryption Key      | arbitrary    |
 374          */
 375         message_len = msg->data_len;
 376         data = msg->data;
 377         /* verify that everything through the encrypted FEK size is present */
 378         if (message_len < 4) {
 379                 rc = -EIO;
 380                 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
 381                        "message length is [%d]\n", __func__, message_len, 4);
 382                 goto out;
 383         }
 384         if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
 385                 rc = -EIO;
 386                 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
 387                        __func__);
 388                 goto out;
 389         }
 390         if (data[i++]) {
 391                 rc = -EIO;
 392                 printk(KERN_ERR "%s: Status indicator has non zero "
 393                        "value [%d]\n", __func__, data[i-1]);
 394
 395                 goto out;
 396         }
 397         rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
 398                                           &data_len);
 399         if (rc) {
 400                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 401                                 "rc = [%d]\n", rc);
 402                 goto out;
 403         }
 404         i += data_len;
 405         if (message_len < (i + key_rec->enc_key_size)) {
 406                 rc = -EIO;
 407                 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
 408                        __func__, message_len, (i + key_rec->enc_key_size));
 409                 goto out;
 410         }
 411         if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 412                 rc = -EIO;
 413                 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
 414                        "the maximum key size [%d]\n", __func__,
 415                        key_rec->enc_key_size,
 416                        ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 417                 goto out;
 418         }
 419         memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
 420 out:
 421         return rc;
 422 }
 423
 424 /**
 425  * ecryptfs_verify_version
 426  * @version: The version number to confirm
 427  *
 428  * Returns zero on good version; non-zero otherwise
 429  */
 430 static int ecryptfs_verify_version(u16 version)
 431 {
 432         int rc = 0;
 433         unsigned char major;
 434         unsigned char minor;
 435
 436         major = ((version >> 8) & 0xFF);
 437         minor = (version & 0xFF);
 438         if (major != ECRYPTFS_VERSION_MAJOR) {
 439                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 440                                 "Expected [%d]; got [%d]\n",
 441                                 ECRYPTFS_VERSION_MAJOR, major);
 442                 rc = -EINVAL;
 443                 goto out;
 444         }
 445         if (minor != ECRYPTFS_VERSION_MINOR) {
 446                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 447                                 "Expected [%d]; got [%d]\n",
 448                                 ECRYPTFS_VERSION_MINOR, minor);
 449                 rc = -EINVAL;
 450                 goto out;
 451         }
 452 out:
 453         return rc;
 454 }
 455
 456 /**
 457  * ecryptfs_verify_auth_tok_from_key
 458  * @auth_tok_key: key containing the authentication token
 459  * @auth_tok: authentication token
 460  *
 461  * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
 462  * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
 463  */
 464 static int
 465 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
 466                                   struct ecryptfs_auth_tok **auth_tok)
 467 {
 468         int rc = 0;
 469
 470         (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
 471         if (IS_ERR(*auth_tok)) {
 472                 rc = PTR_ERR(*auth_tok);
 473                 *auth_tok = NULL;
 474                 goto out;
 475         }
 476
 477         if (ecryptfs_verify_version((*auth_tok)->version)) {
 478                 printk(KERN_ERR "Data structure version mismatch. Userspace "
 479                        "tools must match eCryptfs kernel module with major "
 480                        "version [%d] and minor version [%d]\n",
 481                        ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
 482                 rc = -EINVAL;
 483                 goto out;
 484         }
 485         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
 486             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
 487                 printk(KERN_ERR "Invalid auth_tok structure "
 488                        "returned from key query\n");
 489                 rc = -EINVAL;
 490                 goto out;
 491         }
 492 out:
 493         return rc;
 494 }
 495
 496 static int
 497 ecryptfs_find_global_auth_tok_for_sig(
 498         struct key **auth_tok_key,
 499         struct ecryptfs_auth_tok **auth_tok,
 500         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
 501 {
 502         struct ecryptfs_global_auth_tok *walker;
 503         int rc = 0;
 504
 505         (*auth_tok_key) = NULL;
 506         (*auth_tok) = NULL;
 507         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 508         list_for_each_entry(walker,
 509                             &mount_crypt_stat->global_auth_tok_list,
 510                             mount_crypt_stat_list) {
 511                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
 512                         continue;
 513
 514                 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
 515                         rc = -EINVAL;
 516                         goto out;
 517                 }
 518
 519                 rc = key_validate(walker->global_auth_tok_key);
 520                 if (rc) {
 521                         if (rc == -EKEYEXPIRED)
 522                                 goto out;
 523                         goto out_invalid_auth_tok;
 524                 }
 525
 526                 down_write(&(walker->global_auth_tok_key->sem));
 527                 rc = ecryptfs_verify_auth_tok_from_key(
 528                                 walker->global_auth_tok_key, auth_tok);
 529                 if (rc)
 530                         goto out_invalid_auth_tok_unlock;
 531
 532                 (*auth_tok_key) = walker->global_auth_tok_key;
 533                 key_get(*auth_tok_key);
 534                 goto out;
 535         }
 536         rc = -ENOENT;
 537         goto out;
 538 out_invalid_auth_tok_unlock:
 539         up_write(&(walker->global_auth_tok_key->sem));
 540 out_invalid_auth_tok:
 541         printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
 542         walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 543         key_put(walker->global_auth_tok_key);
 544         walker->global_auth_tok_key = NULL;
 545 out:
 546         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 547         return rc;
 548 }
 549
 550 /**
 551  * ecryptfs_find_auth_tok_for_sig
 552  * @auth_tok: Set to the matching auth_tok; NULL if not found
 553  * @crypt_stat: inode crypt_stat crypto context
 554  * @sig: Sig of auth_tok to find
 555  *
 556  * For now, this function simply looks at the registered auth_tok's
 557  * linked off the mount_crypt_stat, so all the auth_toks that can be
 558  * used must be registered at mount time. This function could
 559  * potentially try a lot harder to find auth_tok's (e.g., by calling
 560  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
 561  * that static registration of auth_tok's will no longer be necessary.
 562  *
 563  * Returns zero on no error; non-zero on error
 564  */
 565 static int
 566 ecryptfs_find_auth_tok_for_sig(
 567         struct key **auth_tok_key,
 568         struct ecryptfs_auth_tok **auth_tok,
 569         struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 570         char *sig)
 571 {
 572         int rc = 0;
 573
 574         rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
 575                                                    mount_crypt_stat, sig);
 576         if (rc == -ENOENT) {
 577                 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
 578                  * mount_crypt_stat structure, we prevent to use auth toks that
 579                  * are not inserted through the ecryptfs_add_global_auth_tok
 580                  * function.
 581                  */
 582                 if (mount_crypt_stat->flags
 583                                 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
 584                         return -EINVAL;
 585
 586                 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
 587                                                        sig);
 588         }
 589         return rc;
 590 }
 591
 592 /**
 593  * write_tag_70_packet can gobble a lot of stack space. We stuff most
 594  * of the function's parameters in a kmalloc'd struct to help reduce
 595  * eCryptfs' overall stack usage.
 596  */
 597 struct ecryptfs_write_tag_70_packet_silly_stack {
 598         u8 cipher_code;
 599         size_t max_packet_size;
 600         size_t packet_size_len;
 601         size_t block_aligned_filename_size;
 602         size_t block_size;
 603         size_t i;
 604         size_t j;
 605         size_t num_rand_bytes;
 606         struct mutex *tfm_mutex;
 607         char *block_aligned_filename;
 608         struct ecryptfs_auth_tok *auth_tok;
 609         struct scatterlist src_sg[2];
 610         struct scatterlist dst_sg[2];
 611         struct blkcipher_desc desc;
 612         char iv[ECRYPTFS_MAX_IV_BYTES];
 613         char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 614         char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 615         struct hash_desc hash_desc;
 616         struct scatterlist hash_sg;
 617 };
 618
 619 /**
 620  * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
 621  * @filename: NULL-terminated filename string
 622  *
 623  * This is the simplest mechanism for achieving filename encryption in
 624  * eCryptfs. It encrypts the given filename with the mount-wide
 625  * filename encryption key (FNEK) and stores it in a packet to @dest,
 626  * which the callee will encode and write directly into the dentry
 627  * name.
 628  */
 629 int
 630 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
 631                              size_t *packet_size,
 632                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 633                              char *filename, size_t filename_size)
 634 {
 635         struct ecryptfs_write_tag_70_packet_silly_stack *s;
 636         struct key *auth_tok_key = NULL;
 637         int rc = 0;
 638
 639         s = kmalloc(sizeof(*s), GFP_KERNEL);
 640         if (!s) {
 641                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 642                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 643                 rc = -ENOMEM;
 644                 goto out;
 645         }
 646         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 647         (*packet_size) = 0;
 648         rc = ecryptfs_find_auth_tok_for_sig(
 649                 &auth_tok_key,
 650                 &s->auth_tok, mount_crypt_stat,
 651                 mount_crypt_stat->global_default_fnek_sig);
 652         if (rc) {
 653                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 654                        "fnek sig [%s]; rc = [%d]\n", __func__,
 655                        mount_crypt_stat->global_default_fnek_sig, rc);
 656                 goto out;
 657         }
 658         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
 659                 &s->desc.tfm,
 660                 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
 661         if (unlikely(rc)) {
 662                 printk(KERN_ERR "Internal error whilst attempting to get "
 663                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
 664                        mount_crypt_stat->global_default_fn_cipher_name, rc);
 665                 goto out;
 666         }
 667         mutex_lock(s->tfm_mutex);
 668         s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
 669         /* Plus one for the \0 separator between the random prefix
 670          * and the plaintext filename */
 671         s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
 672         s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
 673         if ((s->block_aligned_filename_size % s->block_size) != 0) {
 674                 s->num_rand_bytes += (s->block_size
 675                                       - (s->block_aligned_filename_size
 676                                          % s->block_size));
 677                 s->block_aligned_filename_size = (s->num_rand_bytes
 678                                                   + filename_size);
 679         }
 680         /* Octet 0: Tag 70 identifier
 681          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 682          *              and block-aligned encrypted filename size)
 683          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 684          * Octet N2-N3: Cipher identifier (1 octet)
 685          * Octets N3-N4: Block-aligned encrypted filename
 686          *  - Consists of a minimum number of random characters, a \0
 687          *    separator, and then the filename */
 688         s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
 689                               + s->block_aligned_filename_size);
 690         if (dest == NULL) {
 691                 (*packet_size) = s->max_packet_size;
 692                 goto out_unlock;
 693         }
 694         if (s->max_packet_size > (*remaining_bytes)) {
 695                 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
 696                        "[%zd] available\n", __func__, s->max_packet_size,
 697                        (*remaining_bytes));
 698                 rc = -EINVAL;
 699                 goto out_unlock;
 700         }
 701         s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
 702                                             GFP_KERNEL);
 703         if (!s->block_aligned_filename) {
 704                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 705                        "kzalloc [%zd] bytes\n", __func__,
 706                        s->block_aligned_filename_size);
 707                 rc = -ENOMEM;
 708                 goto out_unlock;
 709         }
 710         s->i = 0;
 711         dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
 712         rc = ecryptfs_write_packet_length(&dest[s->i],
 713                                           (ECRYPTFS_SIG_SIZE
 714                                            + 1 /* Cipher code */
 715                                            + s->block_aligned_filename_size),
 716                                           &s->packet_size_len);
 717         if (rc) {
 718                 printk(KERN_ERR "%s: Error generating tag 70 packet "
 719                        "header; cannot generate packet length; rc = [%d]\n",
 720                        __func__, rc);
 721                 goto out_free_unlock;
 722         }
 723         s->i += s->packet_size_len;
 724         ecryptfs_from_hex(&dest[s->i],
 725                           mount_crypt_stat->global_default_fnek_sig,
 726                           ECRYPTFS_SIG_SIZE);
 727         s->i += ECRYPTFS_SIG_SIZE;
 728         s->cipher_code = ecryptfs_code_for_cipher_string(
 729                 mount_crypt_stat->global_default_fn_cipher_name,
 730                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 731         if (s->cipher_code == 0) {
 732                 printk(KERN_WARNING "%s: Unable to generate code for "
 733                        "cipher [%s] with key bytes [%zd]\n", __func__,
 734                        mount_crypt_stat->global_default_fn_cipher_name,
 735                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 736                 rc = -EINVAL;
 737                 goto out_free_unlock;
 738         }
 739         dest[s->i++] = s->cipher_code;
 740         /* TODO: Support other key modules than passphrase for
 741          * filename encryption */
 742         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
 743                 rc = -EOPNOTSUPP;
 744                 printk(KERN_INFO "%s: Filename encryption only supports "
 745                        "password tokens\n", __func__);
 746                 goto out_free_unlock;
 747         }
 748         sg_init_one(
 749                 &s->hash_sg,
 750                 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
 751                 s->auth_tok->token.password.session_key_encryption_key_bytes);
 752         s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 753         s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
 754                                              CRYPTO_ALG_ASYNC);
 755         if (IS_ERR(s->hash_desc.tfm)) {
 756                         rc = PTR_ERR(s->hash_desc.tfm);
 757                         printk(KERN_ERR "%s: Error attempting to "
 758                                "allocate hash crypto context; rc = [%d]\n",
 759                                __func__, rc);
 760                         goto out_free_unlock;
 761         }
 762         rc = crypto_hash_init(&s->hash_desc);
 763         if (rc) {
 764                 printk(KERN_ERR
 765                        "%s: Error initializing crypto hash; rc = [%d]\n",
 766                        __func__, rc);
 767                 goto out_release_free_unlock;
 768         }
 769         rc = crypto_hash_update(
 770                 &s->hash_desc, &s->hash_sg,
 771                 s->auth_tok->token.password.session_key_encryption_key_bytes);
 772         if (rc) {
 773                 printk(KERN_ERR
 774                        "%s: Error updating crypto hash; rc = [%d]\n",
 775                        __func__, rc);
 776                 goto out_release_free_unlock;
 777         }
 778         rc = crypto_hash_final(&s->hash_desc, s->hash);
 779         if (rc) {
 780                 printk(KERN_ERR
 781                        "%s: Error finalizing crypto hash; rc = [%d]\n",
 782                        __func__, rc);
 783                 goto out_release_free_unlock;
 784         }
 785         for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
 786                 s->block_aligned_filename[s->j] =
 787                         s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
 788                 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
 789                     == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
 790                         sg_init_one(&s->hash_sg, (u8 *)s->hash,
 791                                     ECRYPTFS_TAG_70_DIGEST_SIZE);
 792                         rc = crypto_hash_init(&s->hash_desc);
 793                         if (rc) {
 794                                 printk(KERN_ERR
 795                                        "%s: Error initializing crypto hash; "
 796                                        "rc = [%d]\n", __func__, rc);
 797                                 goto out_release_free_unlock;
 798                         }
 799                         rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
 800                                                 ECRYPTFS_TAG_70_DIGEST_SIZE);
 801                         if (rc) {
 802                                 printk(KERN_ERR
 803                                        "%s: Error updating crypto hash; "
 804                                        "rc = [%d]\n", __func__, rc);
 805                                 goto out_release_free_unlock;
 806                         }
 807                         rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
 808                         if (rc) {
 809                                 printk(KERN_ERR
 810                                        "%s: Error finalizing crypto hash; "
 811                                        "rc = [%d]\n", __func__, rc);
 812                                 goto out_release_free_unlock;
 813                         }
 814                         memcpy(s->hash, s->tmp_hash,
 815                                ECRYPTFS_TAG_70_DIGEST_SIZE);
 816                 }
 817                 if (s->block_aligned_filename[s->j] == '\0')
 818                         s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
 819         }
 820         memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
 821                filename_size);
 822         rc = virt_to_scatterlist(s->block_aligned_filename,
 823                                  s->block_aligned_filename_size, s->src_sg, 2);
 824         if (rc < 1) {
 825                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 826                        "convert filename memory to scatterlist; rc = [%d]. "
 827                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 828                        s->block_aligned_filename_size);
 829                 goto out_release_free_unlock;
 830         }
 831         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
 832                                  s->dst_sg, 2);
 833         if (rc < 1) {
 834                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 835                        "convert encrypted filename memory to scatterlist; "
 836                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
 837                        __func__, rc, s->block_aligned_filename_size);
 838                 goto out_release_free_unlock;
 839         }
 840         /* The characters in the first block effectively do the job
 841          * of the IV here, so we just use 0's for the IV. Note the
 842          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
 843          * >= ECRYPTFS_MAX_IV_BYTES. */
 844         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
 845         s->desc.info = s->iv;
 846         rc = crypto_blkcipher_setkey(
 847                 s->desc.tfm,
 848                 s->auth_tok->token.password.session_key_encryption_key,
 849                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 850         if (rc < 0) {
 851                 printk(KERN_ERR "%s: Error setting key for crypto context; "
 852                        "rc = [%d]. s->auth_tok->token.password.session_key_"
 853                        "encryption_key = [0x%p]; mount_crypt_stat->"
 854                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
 855                        rc,
 856                        s->auth_tok->token.password.session_key_encryption_key,
 857                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 858                 goto out_release_free_unlock;
 859         }
 860         rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
 861                                          s->block_aligned_filename_size);
 862         if (rc) {
 863                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
 864                        "rc = [%d]\n", __func__, rc);
 865                 goto out_release_free_unlock;
 866         }
 867         s->i += s->block_aligned_filename_size;
 868         (*packet_size) = s->i;
 869         (*remaining_bytes) -= (*packet_size);
 870 out_release_free_unlock:
 871         crypto_free_hash(s->hash_desc.tfm);
 872 out_free_unlock:
 873         kzfree(s->block_aligned_filename);
 874 out_unlock:
 875         mutex_unlock(s->tfm_mutex);
 876 out:
 877         if (auth_tok_key) {
 878                 up_write(&(auth_tok_key->sem));
 879                 key_put(auth_tok_key);
 880         }
 881         kfree(s);
 882         return rc;
 883 }
 884
 885 struct ecryptfs_parse_tag_70_packet_silly_stack {
 886         u8 cipher_code;
 887         size_t max_packet_size;
 888         size_t packet_size_len;
 889         size_t parsed_tag_70_packet_size;
 890         size_t block_aligned_filename_size;
 891         size_t block_size;
 892         size_t i;
 893         struct mutex *tfm_mutex;
 894         char *decrypted_filename;
 895         struct ecryptfs_auth_tok *auth_tok;
 896         struct scatterlist src_sg[2];
 897         struct scatterlist dst_sg[2];
 898         struct blkcipher_desc desc;
 899         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
 900         char iv[ECRYPTFS_MAX_IV_BYTES];
 901         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
 902 };
 903
 904 /**
 905  * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
 906  * @filename: This function kmalloc's the memory for the filename
 907  * @filename_size: This function sets this to the amount of memory
 908  *                 kmalloc'd for the filename
 909  * @packet_size: This function sets this to the the number of octets
 910  *               in the packet parsed
 911  * @mount_crypt_stat: The mount-wide cryptographic context
 912  * @data: The memory location containing the start of the tag 70
 913  *        packet
 914  * @max_packet_size: The maximum legal size of the packet to be parsed
 915  *                   from @data
 916  *
 917  * Returns zero on success; non-zero otherwise
 918  */
 919 int
 920 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
 921                              size_t *packet_size,
 922                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 923                              char *data, size_t max_packet_size)
 924 {
 925         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
 926         struct key *auth_tok_key = NULL;
 927         int rc = 0;
 928
 929         (*packet_size) = 0;
 930         (*filename_size) = 0;
 931         (*filename) = NULL;
 932         s = kmalloc(sizeof(*s), GFP_KERNEL);
 933         if (!s) {
 934                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 935                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 936                 rc = -ENOMEM;
 937                 goto out;
 938         }
 939         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 940         if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
 941                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
 942                        "at least [%d]\n", __func__, max_packet_size,
 943                        ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
 944                 rc = -EINVAL;
 945                 goto out;
 946         }
 947         /* Octet 0: Tag 70 identifier
 948          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 949          *              and block-aligned encrypted filename size)
 950          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 951          * Octet N2-N3: Cipher identifier (1 octet)
 952          * Octets N3-N4: Block-aligned encrypted filename
 953          *  - Consists of a minimum number of random numbers, a \0
 954          *    separator, and then the filename */
 955         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
 956                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
 957                        "tag [0x%.2x]\n", __func__,
 958                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
 959                 rc = -EINVAL;
 960                 goto out;
 961         }
 962         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
 963                                           &s->parsed_tag_70_packet_size,
 964                                           &s->packet_size_len);
 965         if (rc) {
 966                 printk(KERN_WARNING "%s: Error parsing packet length; "
 967                        "rc = [%d]\n", __func__, rc);
 968                 goto out;
 969         }
 970         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
 971                                           - ECRYPTFS_SIG_SIZE - 1);
 972         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
 973             > max_packet_size) {
 974                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
 975                        "size is [%zd]\n", __func__, max_packet_size,
 976                        (1 + s->packet_size_len + 1
 977                         + s->block_aligned_filename_size));
 978                 rc = -EINVAL;
 979                 goto out;
 980         }
 981         (*packet_size) += s->packet_size_len;
 982         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
 983                         ECRYPTFS_SIG_SIZE);
 984         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 985         (*packet_size) += ECRYPTFS_SIG_SIZE;
 986         s->cipher_code = data[(*packet_size)++];
 987         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
 988         if (rc) {
 989                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
 990                        __func__, s->cipher_code);
 991                 goto out;
 992         }
 993         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
 994                                             &s->auth_tok, mount_crypt_stat,
 995                                             s->fnek_sig_hex);
 996         if (rc) {
 997                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 998                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
 999                        rc);
1000                 goto out;
1001         }
1002         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
1003                                                         &s->tfm_mutex,
1004                                                         s->cipher_string);
1005         if (unlikely(rc)) {
1006                 printk(KERN_ERR "Internal error whilst attempting to get "
1007                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1008                        s->cipher_string, rc);
1009                 goto out;
1010         }
1011         mutex_lock(s->tfm_mutex);
1012         rc = virt_to_scatterlist(&data[(*packet_size)],
1013                                  s->block_aligned_filename_size, s->src_sg, 2);
1014         if (rc < 1) {
1015                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1016                        "convert encrypted filename memory to scatterlist; "
1017                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1018                        __func__, rc, s->block_aligned_filename_size);
1019                 goto out_unlock;
1020         }
1021         (*packet_size) += s->block_aligned_filename_size;
1022         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1023                                         GFP_KERNEL);
1024         if (!s->decrypted_filename) {
1025                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1026                        "kmalloc [%zd] bytes\n", __func__,
1027                        s->block_aligned_filename_size);
1028                 rc = -ENOMEM;
1029                 goto out_unlock;
1030         }
1031         rc = virt_to_scatterlist(s->decrypted_filename,
1032                                  s->block_aligned_filename_size, s->dst_sg, 2);
1033         if (rc < 1) {
1034                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1035                        "convert decrypted filename memory to scatterlist; "
1036                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1037                        __func__, rc, s->block_aligned_filename_size);
1038                 goto out_free_unlock;
1039         }
1040         /* The characters in the first block effectively do the job of
1041          * the IV here, so we just use 0's for the IV. Note the
1042          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1043          * >= ECRYPTFS_MAX_IV_BYTES. */
1044         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1045         s->desc.info = s->iv;
1046         /* TODO: Support other key modules than passphrase for
1047          * filename encryption */
1048         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1049                 rc = -EOPNOTSUPP;
1050                 printk(KERN_INFO "%s: Filename encryption only supports "
1051                        "password tokens\n", __func__);
1052                 goto out_free_unlock;
1053         }
1054         rc = crypto_blkcipher_setkey(
1055                 s->desc.tfm,
1056                 s->auth_tok->token.password.session_key_encryption_key,
1057                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1058         if (rc < 0) {
1059                 printk(KERN_ERR "%s: Error setting key for crypto context; "
1060                        "rc = [%d]. s->auth_tok->token.password.session_key_"
1061                        "encryption_key = [0x%p]; mount_crypt_stat->"
1062                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1063                        rc,
1064                        s->auth_tok->token.password.session_key_encryption_key,
1065                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
1066                 goto out_free_unlock;
1067         }
1068         rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1069                                          s->block_aligned_filename_size);
1070         if (rc) {
1071                 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1072                        "rc = [%d]\n", __func__, rc);
1073                 goto out_free_unlock;
1074         }
1075         s->i = 0;
1076         while (s->decrypted_filename[s->i] != '\0'
1077                && s->i < s->block_aligned_filename_size)
1078                 s->i++;
1079         if (s->i == s->block_aligned_filename_size) {
1080                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1081                        "find valid separator between random characters and "
1082                        "the filename\n", __func__);
1083                 rc = -EINVAL;
1084                 goto out_free_unlock;
1085         }
1086         s->i++;
1087         (*filename_size) = (s->block_aligned_filename_size - s->i);
1088         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1089                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1090                        "invalid\n", __func__, (*filename_size));
1091                 rc = -EINVAL;
1092                 goto out_free_unlock;
1093         }
1094         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1095         if (!(*filename)) {
1096                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1097                        "kmalloc [%zd] bytes\n", __func__,
1098                        ((*filename_size) + 1));
1099                 rc = -ENOMEM;
1100                 goto out_free_unlock;
1101         }
1102         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1103         (*filename)[(*filename_size)] = '\0';
1104 out_free_unlock:
1105         kfree(s->decrypted_filename);
1106 out_unlock:
1107         mutex_unlock(s->tfm_mutex);
1108 out:
1109         if (rc) {
1110                 (*packet_size) = 0;
1111                 (*filename_size) = 0;
1112                 (*filename) = NULL;
1113         }
1114         if (auth_tok_key) {
1115                 up_write(&(auth_tok_key->sem));
1116                 key_put(auth_tok_key);
1117         }
1118         kfree(s);
1119         return rc;
1120 }
1121
1122 static int
1123 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1124 {
1125         int rc = 0;
1126
1127         (*sig) = NULL;
1128         switch (auth_tok->token_type) {
1129         case ECRYPTFS_PASSWORD:
1130                 (*sig) = auth_tok->token.password.signature;
1131                 break;
1132         case ECRYPTFS_PRIVATE_KEY:
1133                 (*sig) = auth_tok->token.private_key.signature;
1134                 break;
1135         default:
1136                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1137                        auth_tok->token_type);
1138                 rc = -EINVAL;
1139         }
1140         return rc;
1141 }
1142
1143 /**
1144  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1145  * @auth_tok: The key authentication token used to decrypt the session key
1146  * @crypt_stat: The cryptographic context
1147  *
1148  * Returns zero on success; non-zero error otherwise.
1149  */
1150 static int
1151 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1152                                   struct ecryptfs_crypt_stat *crypt_stat)
1153 {
1154         u8 cipher_code = 0;
1155         struct ecryptfs_msg_ctx *msg_ctx;
1156         struct ecryptfs_message *msg = NULL;
1157         char *auth_tok_sig;
1158         char *payload = NULL;
1159         size_t payload_len = 0;
1160         int rc;
1161
1162         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1163         if (rc) {
1164                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1165                        auth_tok->token_type);
1166                 goto out;
1167         }
1168         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1169                                  &payload, &payload_len);
1170         if (rc) {
1171                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1172                 goto out;
1173         }
1174         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1175         if (rc) {
1176                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1177                                 "ecryptfsd: %d\n", rc);
1178                 goto out;
1179         }
1180         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1181         if (rc) {
1182                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1183                                 "from the user space daemon\n");
1184                 rc = -EIO;
1185                 goto out;
1186         }
1187         rc = parse_tag_65_packet(&(auth_tok->session_key),
1188                                  &cipher_code, msg);
1189         if (rc) {
1190                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1191                        rc);
1192                 goto out;
1193         }
1194         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1195         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1196                auth_tok->session_key.decrypted_key_size);
1197         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1198         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1199         if (rc) {
1200                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1201                                 cipher_code)
1202                 goto out;
1203         }
1204         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1205         if (ecryptfs_verbosity > 0) {
1206                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1207                 ecryptfs_dump_hex(crypt_stat->key,
1208                                   crypt_stat->key_size);
1209         }
1210 out:
1211         kfree(msg);
1212         kfree(payload);
1213         return rc;
1214 }
1215
1216 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1217 {
1218         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1219         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1220
1221         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1222                                  auth_tok_list_head, list) {
1223                 list_del(&auth_tok_list_item->list);
1224                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1225                                 auth_tok_list_item);
1226         }
1227 }
1228
1229 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1230
1231 /**
1232  * parse_tag_1_packet
1233  * @crypt_stat: The cryptographic context to modify based on packet contents
1234  * @data: The raw bytes of the packet.
1235  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1236  *                 a new authentication token will be placed at the
1237  *                 end of this list for this packet.
1238  * @new_auth_tok: Pointer to a pointer to memory that this function
1239  *                allocates; sets the memory address of the pointer to
1240  *                NULL on error. This object is added to the
1241  *                auth_tok_list.
1242  * @packet_size: This function writes the size of the parsed packet
1243  *               into this memory location; zero on error.
1244  * @max_packet_size: The maximum allowable packet size
1245  *
1246  * Returns zero on success; non-zero on error.
1247  */
1248 static int
1249 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1250                    unsigned char *data, struct list_head *auth_tok_list,
1251                    struct ecryptfs_auth_tok **new_auth_tok,
1252                    size_t *packet_size, size_t max_packet_size)
1253 {
1254         size_t body_size;
1255         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1256         size_t length_size;
1257         int rc = 0;
1258
1259         (*packet_size) = 0;
1260         (*new_auth_tok) = NULL;
1261         /**
1262          * This format is inspired by OpenPGP; see RFC 2440
1263          * packet tag 1
1264          *
1265          * Tag 1 identifier (1 byte)
1266          * Max Tag 1 packet size (max 3 bytes)
1267          * Version (1 byte)
1268          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1269          * Cipher identifier (1 byte)
1270          * Encrypted key size (arbitrary)
1271          *
1272          * 12 bytes minimum packet size
1273          */
1274         if (unlikely(max_packet_size < 12)) {
1275                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1276                 rc = -EINVAL;
1277                 goto out;
1278         }
1279         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1280                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1281                        ECRYPTFS_TAG_1_PACKET_TYPE);
1282                 rc = -EINVAL;
1283                 goto out;
1284         }
1285         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1286          * at end of function upon failure */
1287         auth_tok_list_item =
1288                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1289                                   GFP_KERNEL);
1290         if (!auth_tok_list_item) {
1291                 printk(KERN_ERR "Unable to allocate memory\n");
1292                 rc = -ENOMEM;
1293                 goto out;
1294         }
1295         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1296         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1297                                           &length_size);
1298         if (rc) {
1299                 printk(KERN_WARNING "Error parsing packet length; "
1300                        "rc = [%d]\n", rc);
1301                 goto out_free;
1302         }
1303         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1304                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1305                 rc = -EINVAL;
1306                 goto out_free;
1307         }
1308         (*packet_size) += length_size;
1309         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1310                 printk(KERN_WARNING "Packet size exceeds max\n");
1311                 rc = -EINVAL;
1312                 goto out_free;
1313         }
1314         if (unlikely(data[(*packet_size)++] != 0x03)) {
1315                 printk(KERN_WARNING "Unknown version number [%d]\n",
1316                        data[(*packet_size) - 1]);
1317                 rc = -EINVAL;
1318                 goto out_free;
1319         }
1320         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1321                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1322         *packet_size += ECRYPTFS_SIG_SIZE;
1323         /* This byte is skipped because the kernel does not need to
1324          * know which public key encryption algorithm was used */
1325         (*packet_size)++;
1326         (*new_auth_tok)->session_key.encrypted_key_size =
1327                 body_size - (ECRYPTFS_SIG_SIZE + 2);
1328         if ((*new_auth_tok)->session_key.encrypted_key_size
1329             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1330                 printk(KERN_WARNING "Tag 1 packet contains key larger "
1331                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1332                 rc = -EINVAL;
1333                 goto out_free;
1334         }
1335         memcpy((*new_auth_tok)->session_key.encrypted_key,
1336                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1337         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1338         (*new_auth_tok)->session_key.flags &=
1339                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1340         (*new_auth_tok)->session_key.flags |=
1341                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1342         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1343         (*new_auth_tok)->flags = 0;
1344         (*new_auth_tok)->session_key.flags &=
1345                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1346         (*new_auth_tok)->session_key.flags &=
1347                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1348         list_add(&auth_tok_list_item->list, auth_tok_list);
1349         goto out;
1350 out_free:
1351         (*new_auth_tok) = NULL;
1352         memset(auth_tok_list_item, 0,
1353                sizeof(struct ecryptfs_auth_tok_list_item));
1354         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1355                         auth_tok_list_item);
1356 out:
1357         if (rc)
1358                 (*packet_size) = 0;
1359         return rc;
1360 }
1361
1362 /**
1363  * parse_tag_3_packet
1364  * @crypt_stat: The cryptographic context to modify based on packet
1365  *              contents.
1366  * @data: The raw bytes of the packet.
1367  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1368  *                 a new authentication token will be placed at the end
1369  *                 of this list for this packet.
1370  * @new_auth_tok: Pointer to a pointer to memory that this function
1371  *                allocates; sets the memory address of the pointer to
1372  *                NULL on error. This object is added to the
1373  *                auth_tok_list.
1374  * @packet_size: This function writes the size of the parsed packet
1375  *               into this memory location; zero on error.
1376  * @max_packet_size: maximum number of bytes to parse
1377  *
1378  * Returns zero on success; non-zero on error.
1379  */
1380 static int
1381 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1382                    unsigned char *data, struct list_head *auth_tok_list,
1383                    struct ecryptfs_auth_tok **new_auth_tok,
1384                    size_t *packet_size, size_t max_packet_size)
1385 {
1386         size_t body_size;
1387         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1388         size_t length_size;
1389         int rc = 0;
1390
1391         (*packet_size) = 0;
1392         (*new_auth_tok) = NULL;
1393         /**
1394          *This format is inspired by OpenPGP; see RFC 2440
1395          * packet tag 3
1396          *
1397          * Tag 3 identifier (1 byte)
1398          * Max Tag 3 packet size (max 3 bytes)
1399          * Version (1 byte)
1400          * Cipher code (1 byte)
1401          * S2K specifier (1 byte)
1402          * Hash identifier (1 byte)
1403          * Salt (ECRYPTFS_SALT_SIZE)
1404          * Hash iterations (1 byte)
1405          * Encrypted key (arbitrary)
1406          *
1407          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1408          */
1409         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1410                 printk(KERN_ERR "Max packet size too large\n");
1411                 rc = -EINVAL;
1412                 goto out;
1413         }
1414         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1415                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1416                        ECRYPTFS_TAG_3_PACKET_TYPE);
1417                 rc = -EINVAL;
1418                 goto out;
1419         }
1420         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1421          * at end of function upon failure */
1422         auth_tok_list_item =
1423             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1424         if (!auth_tok_list_item) {
1425                 printk(KERN_ERR "Unable to allocate memory\n");
1426                 rc = -ENOMEM;
1427                 goto out;
1428         }
1429         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1430         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1431                                           &length_size);
1432         if (rc) {
1433                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1434                        rc);
1435                 goto out_free;
1436         }
1437         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1438                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1439                 rc = -EINVAL;
1440                 goto out_free;
1441         }
1442         (*packet_size) += length_size;
1443         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1444                 printk(KERN_ERR "Packet size exceeds max\n");
1445                 rc = -EINVAL;
1446                 goto out_free;
1447         }
1448         (*new_auth_tok)->session_key.encrypted_key_size =
1449                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1450         if ((*new_auth_tok)->session_key.encrypted_key_size
1451             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1452                 printk(KERN_WARNING "Tag 3 packet contains key larger "
1453                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1454                 rc = -EINVAL;
1455                 goto out_free;
1456         }
1457         if (unlikely(data[(*packet_size)++] != 0x04)) {
1458                 printk(KERN_WARNING "Unknown version number [%d]\n",
1459                        data[(*packet_size) - 1]);
1460                 rc = -EINVAL;
1461                 goto out_free;
1462         }
1463         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1464                                             (u16)data[(*packet_size)]);
1465         if (rc)
1466                 goto out_free;
1467         /* A little extra work to differentiate among the AES key
1468          * sizes; see RFC2440 */
1469         switch(data[(*packet_size)++]) {
1470         case RFC2440_CIPHER_AES_192:
1471                 crypt_stat->key_size = 24;
1472                 break;
1473         default:
1474                 crypt_stat->key_size =
1475                         (*new_auth_tok)->session_key.encrypted_key_size;
1476         }
1477         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1478         if (rc)
1479                 goto out_free;
1480         if (unlikely(data[(*packet_size)++] != 0x03)) {
1481                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1482                 rc = -ENOSYS;
1483                 goto out_free;
1484         }
1485         /* TODO: finish the hash mapping */
1486         switch (data[(*packet_size)++]) {
1487         case 0x01: /* See RFC2440 for these numbers and their mappings */
1488                 /* Choose MD5 */
1489                 memcpy((*new_auth_tok)->token.password.salt,
1490                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1491                 (*packet_size) += ECRYPTFS_SALT_SIZE;
1492                 /* This conversion was taken straight from RFC2440 */
1493                 (*new_auth_tok)->token.password.hash_iterations =
1494                         ((u32) 16 + (data[(*packet_size)] & 15))
1495                                 << ((data[(*packet_size)] >> 4) + 6);
1496                 (*packet_size)++;
1497                 /* Friendly reminder:
1498                  * (*new_auth_tok)->session_key.encrypted_key_size =
1499                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1500                 memcpy((*new_auth_tok)->session_key.encrypted_key,
1501                        &data[(*packet_size)],
1502                        (*new_auth_tok)->session_key.encrypted_key_size);
1503                 (*packet_size) +=
1504                         (*new_auth_tok)->session_key.encrypted_key_size;
1505                 (*new_auth_tok)->session_key.flags &=
1506                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1507                 (*new_auth_tok)->session_key.flags |=
1508                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1509                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1510                 break;
1511         default:
1512                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1513                                 "[%d]\n", data[(*packet_size) - 1]);
1514                 rc = -ENOSYS;
1515                 goto out_free;
1516         }
1517         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1518         /* TODO: Parametarize; we might actually want userspace to
1519          * decrypt the session key. */
1520         (*new_auth_tok)->session_key.flags &=
1521                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1522         (*new_auth_tok)->session_key.flags &=
1523                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1524         list_add(&auth_tok_list_item->list, auth_tok_list);
1525         goto out;
1526 out_free:
1527         (*new_auth_tok) = NULL;
1528         memset(auth_tok_list_item, 0,
1529                sizeof(struct ecryptfs_auth_tok_list_item));
1530         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1531                         auth_tok_list_item);
1532 out:
1533         if (rc)
1534                 (*packet_size) = 0;
1535         return rc;
1536 }
1537
1538 /**
1539  * parse_tag_11_packet
1540  * @data: The raw bytes of the packet
1541  * @contents: This function writes the data contents of the literal
1542  *            packet into this memory location
1543  * @max_contents_bytes: The maximum number of bytes that this function
1544  *                      is allowed to write into contents
1545  * @tag_11_contents_size: This function writes the size of the parsed
1546  *                        contents into this memory location; zero on
1547  *                        error
1548  * @packet_size: This function writes the size of the parsed packet
1549  *               into this memory location; zero on error
1550  * @max_packet_size: maximum number of bytes to parse
1551  *
1552  * Returns zero on success; non-zero on error.
1553  */
1554 static int
1555 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1556                     size_t max_contents_bytes, size_t *tag_11_contents_size,
1557                     size_t *packet_size, size_t max_packet_size)
1558 {
1559         size_t body_size;
1560         size_t length_size;
1561         int rc = 0;
1562
1563         (*packet_size) = 0;
1564         (*tag_11_contents_size) = 0;
1565         /* This format is inspired by OpenPGP; see RFC 2440
1566          * packet tag 11
1567          *
1568          * Tag 11 identifier (1 byte)
1569          * Max Tag 11 packet size (max 3 bytes)
1570          * Binary format specifier (1 byte)
1571          * Filename length (1 byte)
1572          * Filename ("_CONSOLE") (8 bytes)
1573          * Modification date (4 bytes)
1574          * Literal data (arbitrary)
1575          *
1576          * We need at least 16 bytes of data for the packet to even be
1577          * valid.
1578          */
1579         if (max_packet_size < 16) {
1580                 printk(KERN_ERR "Maximum packet size too small\n");
1581                 rc = -EINVAL;
1582                 goto out;
1583         }
1584         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1585                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1586                 rc = -EINVAL;
1587                 goto out;
1588         }
1589         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1590                                           &length_size);
1591         if (rc) {
1592                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1593                 goto out;
1594         }
1595         if (body_size < 14) {
1596                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1597                 rc = -EINVAL;
1598                 goto out;
1599         }
1600         (*packet_size) += length_size;
1601         (*tag_11_contents_size) = (body_size - 14);
1602         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1603                 printk(KERN_ERR "Packet size exceeds max\n");
1604                 rc = -EINVAL;
1605                 goto out;
1606         }
1607         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1608                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1609                        "expected size\n");
1610                 rc = -EINVAL;
1611                 goto out;
1612         }
1613         if (data[(*packet_size)++] != 0x62) {
1614                 printk(KERN_WARNING "Unrecognizable packet\n");
1615                 rc = -EINVAL;
1616                 goto out;
1617         }
1618         if (data[(*packet_size)++] != 0x08) {
1619                 printk(KERN_WARNING "Unrecognizable packet\n");
1620                 rc = -EINVAL;
1621                 goto out;
1622         }
1623         (*packet_size) += 12; /* Ignore filename and modification date */
1624         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1625         (*packet_size) += (*tag_11_contents_size);
1626 out:
1627         if (rc) {
1628                 (*packet_size) = 0;
1629                 (*tag_11_contents_size) = 0;
1630         }
1631         return rc;
1632 }
1633
1634 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1635                                       struct ecryptfs_auth_tok **auth_tok,
1636                                       char *sig)
1637 {
1638         int rc = 0;
1639
1640         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1641         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1642                 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1643                 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1644                         printk(KERN_ERR "Could not find key with description: [%s]\n",
1645                               sig);
1646                         rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1647                         (*auth_tok_key) = NULL;
1648                         goto out;
1649                 }
1650         }
1651         down_write(&(*auth_tok_key)->sem);
1652         rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1653         if (rc) {
1654                 up_write(&(*auth_tok_key)->sem);
1655                 key_put(*auth_tok_key);
1656                 (*auth_tok_key) = NULL;
1657                 goto out;
1658         }
1659 out:
1660         return rc;
1661 }
1662
1663 /**
1664  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1665  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1666  * @crypt_stat: The cryptographic context
1667  *
1668  * Returns zero on success; non-zero error otherwise
1669  */
1670 static int
1671 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1672                                          struct ecryptfs_crypt_stat *crypt_stat)
1673 {
1674         struct scatterlist dst_sg[2];
1675         struct scatterlist src_sg[2];
1676         struct mutex *tfm_mutex;
1677         struct blkcipher_desc desc = {
1678                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1679         };
1680         int rc = 0;
1681
1682         if (unlikely(ecryptfs_verbosity > 0)) {
1683                 ecryptfs_printk(
1684                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1685                         auth_tok->token.password.session_key_encryption_key_bytes);
1686                 ecryptfs_dump_hex(
1687                         auth_tok->token.password.session_key_encryption_key,
1688                         auth_tok->token.password.session_key_encryption_key_bytes);
1689         }
1690         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1691                                                         crypt_stat->cipher);
1692         if (unlikely(rc)) {
1693                 printk(KERN_ERR "Internal error whilst attempting to get "
1694                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1695                        crypt_stat->cipher, rc);
1696                 goto out;
1697         }
1698         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1699                                  auth_tok->session_key.encrypted_key_size,
1700                                  src_sg, 2);
1701         if (rc < 1 || rc > 2) {
1702                 printk(KERN_ERR "Internal error whilst attempting to convert "
1703                         "auth_tok->session_key.encrypted_key to scatterlist; "
1704                         "expected rc = 1; got rc = [%d]. "
1705                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1706                         auth_tok->session_key.encrypted_key_size);
1707                 goto out;
1708         }
1709         auth_tok->session_key.decrypted_key_size =
1710                 auth_tok->session_key.encrypted_key_size;
1711         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1712                                  auth_tok->session_key.decrypted_key_size,
1713                                  dst_sg, 2);
1714         if (rc < 1 || rc > 2) {
1715                 printk(KERN_ERR "Internal error whilst attempting to convert "
1716                         "auth_tok->session_key.decrypted_key to scatterlist; "
1717                         "expected rc = 1; got rc = [%d]\n", rc);
1718                 goto out;
1719         }
1720         mutex_lock(tfm_mutex);
1721         rc = crypto_blkcipher_setkey(
1722                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1723                 crypt_stat->key_size);
1724         if (unlikely(rc < 0)) {
1725                 mutex_unlock(tfm_mutex);
1726                 printk(KERN_ERR "Error setting key for crypto context\n");
1727                 rc = -EINVAL;
1728                 goto out;
1729         }
1730         rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1731                                       auth_tok->session_key.encrypted_key_size);
1732         mutex_unlock(tfm_mutex);
1733         if (unlikely(rc)) {
1734                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1735                 goto out;
1736         }
1737         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1738         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1739                auth_tok->session_key.decrypted_key_size);
1740         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1741         if (unlikely(ecryptfs_verbosity > 0)) {
1742                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1743                                 crypt_stat->key_size);
1744                 ecryptfs_dump_hex(crypt_stat->key,
1745                                   crypt_stat->key_size);
1746         }
1747 out:
1748         return rc;
1749 }
1750
1751 /**
1752  * ecryptfs_parse_packet_set
1753  * @crypt_stat: The cryptographic context
1754  * @src: Virtual address of region of memory containing the packets
1755  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1756  *
1757  * Get crypt_stat to have the file's session key if the requisite key
1758  * is available to decrypt the session key.
1759  *
1760  * Returns Zero if a valid authentication token was retrieved and
1761  * processed; negative value for file not encrypted or for error
1762  * conditions.
1763  */
1764 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1765                               unsigned char *src,
1766                               struct dentry *ecryptfs_dentry)
1767 {
1768         size_t i = 0;
1769         size_t found_auth_tok;
1770         size_t next_packet_is_auth_tok_packet;
1771         struct list_head auth_tok_list;
1772         struct ecryptfs_auth_tok *matching_auth_tok;
1773         struct ecryptfs_auth_tok *candidate_auth_tok;
1774         char *candidate_auth_tok_sig;
1775         size_t packet_size;
1776         struct ecryptfs_auth_tok *new_auth_tok;
1777         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1778         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1779         size_t tag_11_contents_size;
1780         size_t tag_11_packet_size;
1781         struct key *auth_tok_key = NULL;
1782         int rc = 0;
1783
1784         INIT_LIST_HEAD(&auth_tok_list);
1785         /* Parse the header to find as many packets as we can; these will be
1786          * added the our &auth_tok_list */
1787         next_packet_is_auth_tok_packet = 1;
1788         while (next_packet_is_auth_tok_packet) {
1789                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1790
1791                 switch (src[i]) {
1792                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1793                         rc = parse_tag_3_packet(crypt_stat,
1794                                                 (unsigned char *)&src[i],
1795                                                 &auth_tok_list, &new_auth_tok,
1796                                                 &packet_size, max_packet_size);
1797                         if (rc) {
1798                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1799                                                 "tag 3 packet\n");
1800                                 rc = -EIO;
1801                                 goto out_wipe_list;
1802                         }
1803                         i += packet_size;
1804                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1805                                                  sig_tmp_space,
1806                                                  ECRYPTFS_SIG_SIZE,
1807                                                  &tag_11_contents_size,
1808                                                  &tag_11_packet_size,
1809                                                  max_packet_size);
1810                         if (rc) {
1811                                 ecryptfs_printk(KERN_ERR, "No valid "
1812                                                 "(ecryptfs-specific) literal "
1813                                                 "packet containing "
1814                                                 "authentication token "
1815                                                 "signature found after "
1816                                                 "tag 3 packet\n");
1817                                 rc = -EIO;
1818                                 goto out_wipe_list;
1819                         }
1820                         i += tag_11_packet_size;
1821                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1822                                 ecryptfs_printk(KERN_ERR, "Expected "
1823                                                 "signature of size [%d]; "
1824                                                 "read size [%zd]\n",
1825                                                 ECRYPTFS_SIG_SIZE,
1826                                                 tag_11_contents_size);
1827                                 rc = -EIO;
1828                                 goto out_wipe_list;
1829                         }
1830                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1831                                         sig_tmp_space, tag_11_contents_size);
1832                         new_auth_tok->token.password.signature[
1833                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1834                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1835                         break;
1836                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1837                         rc = parse_tag_1_packet(crypt_stat,
1838                                                 (unsigned char *)&src[i],
1839                                                 &auth_tok_list, &new_auth_tok,
1840                                                 &packet_size, max_packet_size);
1841                         if (rc) {
1842                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1843                                                 "tag 1 packet\n");
1844                                 rc = -EIO;
1845                                 goto out_wipe_list;
1846                         }
1847                         i += packet_size;
1848                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1849                         break;
1850                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1851                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1852                                         "(Tag 11 not allowed by itself)\n");
1853                         rc = -EIO;
1854                         goto out_wipe_list;
1855                 default:
1856                         ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1857                                         "of the file header; hex value of "
1858                                         "character is [0x%.2x]\n", i, src[i]);
1859                         next_packet_is_auth_tok_packet = 0;
1860                 }
1861         }
1862         if (list_empty(&auth_tok_list)) {
1863                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1864                        "eCryptfs file; this is not supported in this version "
1865                        "of the eCryptfs kernel module\n");
1866                 rc = -EINVAL;
1867                 goto out;
1868         }
1869         /* auth_tok_list contains the set of authentication tokens
1870          * parsed from the metadata. We need to find a matching
1871          * authentication token that has the secret component(s)
1872          * necessary to decrypt the EFEK in the auth_tok parsed from
1873          * the metadata. There may be several potential matches, but
1874          * just one will be sufficient to decrypt to get the FEK. */
1875 find_next_matching_auth_tok:
1876         found_auth_tok = 0;
1877         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1878                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1879                 if (unlikely(ecryptfs_verbosity > 0)) {
1880                         ecryptfs_printk(KERN_DEBUG,
1881                                         "Considering cadidate auth tok:\n");
1882                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1883                 }
1884                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1885                                                candidate_auth_tok);
1886                 if (rc) {
1887                         printk(KERN_ERR
1888                                "Unrecognized candidate auth tok type: [%d]\n",
1889                                candidate_auth_tok->token_type);
1890                         rc = -EINVAL;
1891                         goto out_wipe_list;
1892                 }
1893                 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1894                                                &matching_auth_tok,
1895                                                crypt_stat->mount_crypt_stat,
1896                                                candidate_auth_tok_sig);
1897                 if (!rc) {
1898                         found_auth_tok = 1;
1899                         goto found_matching_auth_tok;
1900                 }
1901         }
1902         if (!found_auth_tok) {
1903                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1904                                 "authentication token\n");
1905                 rc = -EIO;
1906                 goto out_wipe_list;
1907         }
1908 found_matching_auth_tok:
1909         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1910                 memcpy(&(candidate_auth_tok->token.private_key),
1911                        &(matching_auth_tok->token.private_key),
1912                        sizeof(struct ecryptfs_private_key));
1913                 up_write(&(auth_tok_key->sem));
1914                 key_put(auth_tok_key);
1915                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1916                                                        crypt_stat);
1917         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1918                 memcpy(&(candidate_auth_tok->token.password),
1919                        &(matching_auth_tok->token.password),
1920                        sizeof(struct ecryptfs_password));
1921                 up_write(&(auth_tok_key->sem));
1922                 key_put(auth_tok_key);
1923                 rc = decrypt_passphrase_encrypted_session_key(
1924                         candidate_auth_tok, crypt_stat);
1925         } else {
1926                 up_write(&(auth_tok_key->sem));
1927                 key_put(auth_tok_key);
1928                 rc = -EINVAL;
1929         }
1930         if (rc) {
1931                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1932
1933                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1934                                 "session key for authentication token with sig "
1935                                 "[%.*s]; rc = [%d]. Removing auth tok "
1936                                 "candidate from the list and searching for "
1937                                 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1938                                 candidate_auth_tok_sig, rc);
1939                 list_for_each_entry_safe(auth_tok_list_item,
1940                                          auth_tok_list_item_tmp,
1941                                          &auth_tok_list, list) {
1942                         if (candidate_auth_tok
1943                             == &auth_tok_list_item->auth_tok) {
1944                                 list_del(&auth_tok_list_item->list);
1945                                 kmem_cache_free(
1946                                         ecryptfs_auth_tok_list_item_cache,
1947                                         auth_tok_list_item);
1948                                 goto find_next_matching_auth_tok;
1949                         }
1950                 }
1951                 BUG();
1952         }
1953         rc = ecryptfs_compute_root_iv(crypt_stat);
1954         if (rc) {
1955                 ecryptfs_printk(KERN_ERR, "Error computing "
1956                                 "the root IV\n");
1957                 goto out_wipe_list;
1958         }
1959         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1960         if (rc) {
1961                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1962                                 "context for cipher [%s]; rc = [%d]\n",
1963                                 crypt_stat->cipher, rc);
1964         }
1965 out_wipe_list:
1966         wipe_auth_tok_list(&auth_tok_list);
1967 out:
1968         return rc;
1969 }
1970
1971 static int
1972 pki_encrypt_session_key(struct key *auth_tok_key,
1973                         struct ecryptfs_auth_tok *auth_tok,
1974                         struct ecryptfs_crypt_stat *crypt_stat,
1975                         struct ecryptfs_key_record *key_rec)
1976 {
1977         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1978         char *payload = NULL;
1979         size_t payload_len = 0;
1980         struct ecryptfs_message *msg;
1981         int rc;
1982
1983         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1984                                  ecryptfs_code_for_cipher_string(
1985                                          crypt_stat->cipher,
1986                                          crypt_stat->key_size),
1987                                  crypt_stat, &payload, &payload_len);
1988         up_write(&(auth_tok_key->sem));
1989         key_put(auth_tok_key);
1990         if (rc) {
1991                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1992                 goto out;
1993         }
1994         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1995         if (rc) {
1996                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1997                                 "ecryptfsd: %d\n", rc);
1998                 goto out;
1999         }
2000         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2001         if (rc) {
2002                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2003                                 "from the user space daemon\n");
2004                 rc = -EIO;
2005                 goto out;
2006         }
2007         rc = parse_tag_67_packet(key_rec, msg);
2008         if (rc)
2009                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2010         kfree(msg);
2011 out:
2012         kfree(payload);
2013         return rc;
2014 }
2015 /**
2016  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2017  * @dest: Buffer into which to write the packet
2018  * @remaining_bytes: Maximum number of bytes that can be writtn
2019  * @auth_tok_key: The authentication token key to unlock and put when done with
2020  *                @auth_tok
2021  * @auth_tok: The authentication token used for generating the tag 1 packet
2022  * @crypt_stat: The cryptographic context
2023  * @key_rec: The key record struct for the tag 1 packet
2024  * @packet_size: This function will write the number of bytes that end
2025  *               up constituting the packet; set to zero on error
2026  *
2027  * Returns zero on success; non-zero on error.
2028  */
2029 static int
2030 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2031                    struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2032                    struct ecryptfs_crypt_stat *crypt_stat,
2033                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2034 {
2035         size_t i;
2036         size_t encrypted_session_key_valid = 0;
2037         size_t packet_size_length;
2038         size_t max_packet_size;
2039         int rc = 0;
2040
2041         (*packet_size) = 0;
2042         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2043                           ECRYPTFS_SIG_SIZE);
2044         encrypted_session_key_valid = 0;
2045         for (i = 0; i < crypt_stat->key_size; i++)
2046                 encrypted_session_key_valid |=
2047                         auth_tok->session_key.encrypted_key[i];
2048         if (encrypted_session_key_valid) {
2049                 memcpy(key_rec->enc_key,
2050                        auth_tok->session_key.encrypted_key,
2051                        auth_tok->session_key.encrypted_key_size);
2052                 up_write(&(auth_tok_key->sem));
2053                 key_put(auth_tok_key);
2054                 goto encrypted_session_key_set;
2055         }
2056         if (auth_tok->session_key.encrypted_key_size == 0)
2057                 auth_tok->session_key.encrypted_key_size =
2058                         auth_tok->token.private_key.key_size;
2059         rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2060                                      key_rec);
2061         if (rc) {
2062                 printk(KERN_ERR "Failed to encrypt session key via a key "
2063                        "module; rc = [%d]\n", rc);
2064                 goto out;
2065         }
2066         if (ecryptfs_verbosity > 0) {
2067                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2068                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2069         }
2070 encrypted_session_key_set:
2071         /* This format is inspired by OpenPGP; see RFC 2440
2072          * packet tag 1 */
2073         max_packet_size = (1                         /* Tag 1 identifier */
2074                            + 3                       /* Max Tag 1 packet size */
2075                            + 1                       /* Version */
2076                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
2077                            + 1                       /* Cipher identifier */
2078                            + key_rec->enc_key_size); /* Encrypted key size */
2079         if (max_packet_size > (*remaining_bytes)) {
2080                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2081                        "need up to [%td] bytes, but there are only [%td] "
2082                        "available\n", max_packet_size, (*remaining_bytes));
2083                 rc = -EINVAL;
2084                 goto out;
2085         }
2086         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2087         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2088                                           (max_packet_size - 4),
2089                                           &packet_size_length);
2090         if (rc) {
2091                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2092                                 "header; cannot generate packet length\n");
2093                 goto out;
2094         }
2095         (*packet_size) += packet_size_length;
2096         dest[(*packet_size)++] = 0x03; /* version 3 */
2097         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2098         (*packet_size) += ECRYPTFS_SIG_SIZE;
2099         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2100         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2101                key_rec->enc_key_size);
2102         (*packet_size) += key_rec->enc_key_size;
2103 out:
2104         if (rc)
2105                 (*packet_size) = 0;
2106         else
2107                 (*remaining_bytes) -= (*packet_size);
2108         return rc;
2109 }
2110
2111 /**
2112  * write_tag_11_packet
2113  * @dest: Target into which Tag 11 packet is to be written
2114  * @remaining_bytes: Maximum packet length
2115  * @contents: Byte array of contents to copy in
2116  * @contents_length: Number of bytes in contents
2117  * @packet_length: Length of the Tag 11 packet written; zero on error
2118  *
2119  * Returns zero on success; non-zero on error.
2120  */
2121 static int
2122 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2123                     size_t contents_length, size_t *packet_length)
2124 {
2125         size_t packet_size_length;
2126         size_t max_packet_size;
2127         int rc = 0;
2128
2129         (*packet_length) = 0;
2130         /* This format is inspired by OpenPGP; see RFC 2440
2131          * packet tag 11 */
2132         max_packet_size = (1                   /* Tag 11 identifier */
2133                            + 3                 /* Max Tag 11 packet size */
2134                            + 1                 /* Binary format specifier */
2135                            + 1                 /* Filename length */
2136                            + 8                 /* Filename ("_CONSOLE") */
2137                            + 4                 /* Modification date */
2138                            + contents_length); /* Literal data */
2139         if (max_packet_size > (*remaining_bytes)) {
2140                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2141                        "need up to [%td] bytes, but there are only [%td] "
2142                        "available\n", max_packet_size, (*remaining_bytes));
2143                 rc = -EINVAL;
2144                 goto out;
2145         }
2146         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2147         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2148                                           (max_packet_size - 4),
2149                                           &packet_size_length);
2150         if (rc) {
2151                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2152                        "generate packet length. rc = [%d]\n", rc);
2153                 goto out;
2154         }
2155         (*packet_length) += packet_size_length;
2156         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2157         dest[(*packet_length)++] = 8;
2158         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2159         (*packet_length) += 8;
2160         memset(&dest[(*packet_length)], 0x00, 4);
2161         (*packet_length) += 4;
2162         memcpy(&dest[(*packet_length)], contents, contents_length);
2163         (*packet_length) += contents_length;
2164  out:
2165         if (rc)
2166                 (*packet_length) = 0;
2167         else
2168                 (*remaining_bytes) -= (*packet_length);
2169         return rc;
2170 }
2171
2172 /**
2173  * write_tag_3_packet
2174  * @dest: Buffer into which to write the packet
2175  * @remaining_bytes: Maximum number of bytes that can be written
2176  * @auth_tok: Authentication token
2177  * @crypt_stat: The cryptographic context
2178  * @key_rec: encrypted key
2179  * @packet_size: This function will write the number of bytes that end
2180  *               up constituting the packet; set to zero on error
2181  *
2182  * Returns zero on success; non-zero on error.
2183  */
2184 static int
2185 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2186                    struct ecryptfs_auth_tok *auth_tok,
2187                    struct ecryptfs_crypt_stat *crypt_stat,
2188                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2189 {
2190         size_t i;
2191         size_t encrypted_session_key_valid = 0;
2192         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2193         struct scatterlist dst_sg[2];
2194         struct scatterlist src_sg[2];
2195         struct mutex *tfm_mutex = NULL;
2196         u8 cipher_code;
2197         size_t packet_size_length;
2198         size_t max_packet_size;
2199         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2200                 crypt_stat->mount_crypt_stat;
2201         struct blkcipher_desc desc = {
2202                 .tfm = NULL,
2203                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2204         };
2205         int rc = 0;
2206
2207         (*packet_size) = 0;
2208         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2209                           ECRYPTFS_SIG_SIZE);
2210         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2211                                                         crypt_stat->cipher);
2212         if (unlikely(rc)) {
2213                 printk(KERN_ERR "Internal error whilst attempting to get "
2214                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2215                        crypt_stat->cipher, rc);
2216                 goto out;
2217         }
2218         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2219                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2220
2221                 printk(KERN_WARNING "No key size specified at mount; "
2222                        "defaulting to [%d]\n", alg->max_keysize);
2223                 mount_crypt_stat->global_default_cipher_key_size =
2224                         alg->max_keysize;
2225         }
2226         if (crypt_stat->key_size == 0)
2227                 crypt_stat->key_size =
2228                         mount_crypt_stat->global_default_cipher_key_size;
2229         if (auth_tok->session_key.encrypted_key_size == 0)
2230                 auth_tok->session_key.encrypted_key_size =
2231                         crypt_stat->key_size;
2232         if (crypt_stat->key_size == 24
2233             && strcmp("aes", crypt_stat->cipher) == 0) {
2234                 memset((crypt_stat->key + 24), 0, 8);
2235                 auth_tok->session_key.encrypted_key_size = 32;
2236         } else
2237                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2238         key_rec->enc_key_size =
2239                 auth_tok->session_key.encrypted_key_size;
2240         encrypted_session_key_valid = 0;
2241         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2242                 encrypted_session_key_valid |=
2243                         auth_tok->session_key.encrypted_key[i];
2244         if (encrypted_session_key_valid) {
2245                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2246                                 "using auth_tok->session_key.encrypted_key, "
2247                                 "where key_rec->enc_key_size = [%zd]\n",
2248                                 key_rec->enc_key_size);
2249                 memcpy(key_rec->enc_key,
2250                        auth_tok->session_key.encrypted_key,
2251                        key_rec->enc_key_size);
2252                 goto encrypted_session_key_set;
2253         }
2254         if (auth_tok->token.password.flags &
2255             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2256                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2257                                 "session key encryption key of size [%d]\n",
2258                                 auth_tok->token.password.
2259                                 session_key_encryption_key_bytes);
2260                 memcpy(session_key_encryption_key,
2261                        auth_tok->token.password.session_key_encryption_key,
2262                        crypt_stat->key_size);
2263                 ecryptfs_printk(KERN_DEBUG,
2264                                 "Cached session key encryption key:\n");
2265                 if (ecryptfs_verbosity > 0)
2266                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2267         }
2268         if (unlikely(ecryptfs_verbosity > 0)) {
2269                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2270                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2271         }
2272         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2273                                  src_sg, 2);
2274         if (rc < 1 || rc > 2) {
2275                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2276                                 "for crypt_stat session key; expected rc = 1; "
2277                                 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2278                                 rc, key_rec->enc_key_size);
2279                 rc = -ENOMEM;
2280                 goto out;
2281         }
2282         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2283                                  dst_sg, 2);
2284         if (rc < 1 || rc > 2) {
2285                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2286                                 "for crypt_stat encrypted session key; "
2287                                 "expected rc = 1; got rc = [%d]. "
2288                                 "key_rec->enc_key_size = [%zd]\n", rc,
2289                                 key_rec->enc_key_size);
2290                 rc = -ENOMEM;
2291                 goto out;
2292         }
2293         mutex_lock(tfm_mutex);
2294         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2295                                      crypt_stat->key_size);
2296         if (rc < 0) {
2297                 mutex_unlock(tfm_mutex);
2298                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2299                                 "context; rc = [%d]\n", rc);
2300                 goto out;
2301         }
2302         rc = 0;
2303         ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2304                         crypt_stat->key_size);
2305         rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2306                                       (*key_rec).enc_key_size);
2307         mutex_unlock(tfm_mutex);
2308         if (rc) {
2309                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2310                 goto out;
2311         }
2312         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2313         if (ecryptfs_verbosity > 0) {
2314                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2315                                 key_rec->enc_key_size);
2316                 ecryptfs_dump_hex(key_rec->enc_key,
2317                                   key_rec->enc_key_size);
2318         }
2319 encrypted_session_key_set:
2320         /* This format is inspired by OpenPGP; see RFC 2440
2321          * packet tag 3 */
2322         max_packet_size = (1                         /* Tag 3 identifier */
2323                            + 3                       /* Max Tag 3 packet size */
2324                            + 1                       /* Version */
2325                            + 1                       /* Cipher code */
2326                            + 1                       /* S2K specifier */
2327                            + 1                       /* Hash identifier */
2328                            + ECRYPTFS_SALT_SIZE      /* Salt */
2329                            + 1                       /* Hash iterations */
2330                            + key_rec->enc_key_size); /* Encrypted key size */
2331         if (max_packet_size > (*remaining_bytes)) {
2332                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2333                        "there are only [%td] available\n", max_packet_size,
2334                        (*remaining_bytes));
2335                 rc = -EINVAL;
2336                 goto out;
2337         }
2338         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2339         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2340          * to get the number of octets in the actual Tag 3 packet */
2341         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2342                                           (max_packet_size - 4),
2343                                           &packet_size_length);
2344         if (rc) {
2345                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2346                        "generate packet length. rc = [%d]\n", rc);
2347                 goto out;
2348         }
2349         (*packet_size) += packet_size_length;
2350         dest[(*packet_size)++] = 0x04; /* version 4 */
2351         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2352          * specified with strings */
2353         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2354                                                       crypt_stat->key_size);
2355         if (cipher_code == 0) {
2356                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2357                                 "cipher [%s]\n", crypt_stat->cipher);
2358                 rc = -EINVAL;
2359                 goto out;
2360         }
2361         dest[(*packet_size)++] = cipher_code;
2362         dest[(*packet_size)++] = 0x03;  /* S2K */
2363         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2364         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2365                ECRYPTFS_SALT_SIZE);
2366         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2367         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2368         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2369                key_rec->enc_key_size);
2370         (*packet_size) += key_rec->enc_key_size;
2371 out:
2372         if (rc)
2373                 (*packet_size) = 0;
2374         else
2375                 (*remaining_bytes) -= (*packet_size);
2376         return rc;
2377 }
2378
2379 struct kmem_cache *ecryptfs_key_record_cache;
2380
2381 /**
2382  * ecryptfs_generate_key_packet_set
2383  * @dest_base: Virtual address from which to write the key record set
2384  * @crypt_stat: The cryptographic context from which the
2385  *              authentication tokens will be retrieved
2386  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2387  *                   for the global parameters
2388  * @len: The amount written
2389  * @max: The maximum amount of data allowed to be written
2390  *
2391  * Generates a key packet set and writes it to the virtual address
2392  * passed in.
2393  *
2394  * Returns zero on success; non-zero on error.
2395  */
2396 int
2397 ecryptfs_generate_key_packet_set(char *dest_base,
2398                                  struct ecryptfs_crypt_stat *crypt_stat,
2399                                  struct dentry *ecryptfs_dentry, size_t *len,
2400                                  size_t max)
2401 {
2402         struct ecryptfs_auth_tok *auth_tok;
2403         struct key *auth_tok_key = NULL;
2404         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2405                 &ecryptfs_superblock_to_private(
2406                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2407         size_t written;
2408         struct ecryptfs_key_record *key_rec;
2409         struct ecryptfs_key_sig *key_sig;
2410         int rc = 0;
2411
2412         (*len) = 0;
2413         mutex_lock(&crypt_stat->keysig_list_mutex);
2414         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2415         if (!key_rec) {
2416                 rc = -ENOMEM;
2417                 goto out;
2418         }
2419         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2420                             crypt_stat_list) {
2421                 memset(key_rec, 0, sizeof(*key_rec));
2422                 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2423                                                            &auth_tok,
2424                                                            mount_crypt_stat,
2425                                                            key_sig->keysig);
2426                 if (rc) {
2427                         printk(KERN_WARNING "Unable to retrieve auth tok with "
2428                                "sig = [%s]\n", key_sig->keysig);
2429                         rc = process_find_global_auth_tok_for_sig_err(rc);
2430                         goto out_free;
2431                 }
2432                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2433                         rc = write_tag_3_packet((dest_base + (*len)),
2434                                                 &max, auth_tok,
2435                                                 crypt_stat, key_rec,
2436                                                 &written);
2437                         up_write(&(auth_tok_key->sem));
2438                         key_put(auth_tok_key);
2439                         if (rc) {
2440                                 ecryptfs_printk(KERN_WARNING, "Error "
2441                                                 "writing tag 3 packet\n");
2442                                 goto out_free;
2443                         }
2444                         (*len) += written;
2445                         /* Write auth tok signature packet */
2446                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2447                                                  key_rec->sig,
2448                                                  ECRYPTFS_SIG_SIZE, &written);
2449                         if (rc) {
2450                                 ecryptfs_printk(KERN_ERR, "Error writing "
2451                                                 "auth tok signature packet\n");
2452                                 goto out_free;
2453                         }
2454                         (*len) += written;
2455                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2456                         rc = write_tag_1_packet(dest_base + (*len), &max,
2457                                                 auth_tok_key, auth_tok,
2458                                                 crypt_stat, key_rec, &written);
2459                         if (rc) {
2460                                 ecryptfs_printk(KERN_WARNING, "Error "
2461                                                 "writing tag 1 packet\n");
2462                                 goto out_free;
2463                         }
2464                         (*len) += written;
2465                 } else {
2466                         up_write(&(auth_tok_key->sem));
2467                         key_put(auth_tok_key);
2468                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2469                                         "authentication token type\n");
2470                         rc = -EINVAL;
2471                         goto out_free;
2472                 }
2473         }
2474         if (likely(max > 0)) {
2475                 dest_base[(*len)] = 0x00;
2476         } else {
2477                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2478                 rc = -EIO;
2479         }
2480 out_free:
2481         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2482 out:
2483         if (rc)
2484                 (*len) = 0;
2485         mutex_unlock(&crypt_stat->keysig_list_mutex);
2486         return rc;
2487 }
2488
2489 struct kmem_cache *ecryptfs_key_sig_cache;
2490
2491 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2492 {
2493         struct ecryptfs_key_sig *new_key_sig;
2494
2495         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2496         if (!new_key_sig) {
2497                 printk(KERN_ERR
2498                        "Error allocating from ecryptfs_key_sig_cache\n");
2499                 return -ENOMEM;
2500         }
2501         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2502         new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2503         /* Caller must hold keysig_list_mutex */
2504         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2505
2506         return 0;
2507 }
2508
2509 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2510
2511 int
2512 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2513                              char *sig, u32 global_auth_tok_flags)
2514 {
2515         struct ecryptfs_global_auth_tok *new_auth_tok;
2516         int rc = 0;
2517
2518         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2519                                         GFP_KERNEL);
2520         if (!new_auth_tok) {
2521                 rc = -ENOMEM;
2522                 printk(KERN_ERR "Error allocating from "
2523                        "ecryptfs_global_auth_tok_cache\n");
2524                 goto out;
2525         }
2526         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2527         new_auth_tok->flags = global_auth_tok_flags;
2528         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2529         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2530         list_add(&new_auth_tok->mount_crypt_stat_list,
2531                  &mount_crypt_stat->global_auth_tok_list);
2532         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2533 out:
2534         return rc;
2535 }
2536