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 <crypto/hash.h>
  29 #include <crypto/skcipher.h>
  30 #include <linux/string.h>
  31 #include <linux/pagemap.h>
  32 #include <linux/key.h>
  33 #include <linux/random.h>
  34 #include <linux/scatterlist.h>
  35 #include <linux/slab.h>
  36 #include "ecryptfs_kernel.h"
  37
  38 /**
  39  * request_key returned an error instead of a valid key address;
  40  * determine the type of error, make appropriate log entries, and
  41  * return an error code.
  42  */
  43 static int process_request_key_err(long err_code)
  44 {
  45         int rc = 0;
  46
  47         switch (err_code) {
  48         case -ENOKEY:
  49                 ecryptfs_printk(KERN_WARNING, "No key\n");
  50                 rc = -ENOENT;
  51                 break;
  52         case -EKEYEXPIRED:
  53                 ecryptfs_printk(KERN_WARNING, "Key expired\n");
  54                 rc = -ETIME;
  55                 break;
  56         case -EKEYREVOKED:
  57                 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
  58                 rc = -EINVAL;
  59                 break;
  60         default:
  61                 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
  62                                 "[0x%.16lx]\n", err_code);
  63                 rc = -EINVAL;
  64         }
  65         return rc;
  66 }
  67
  68 static int process_find_global_auth_tok_for_sig_err(int err_code)
  69 {
  70         int rc = err_code;
  71
  72         switch (err_code) {
  73         case -ENOENT:
  74                 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
  75                 break;
  76         case -EINVAL:
  77                 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
  78                 break;
  79         default:
  80                 rc = process_request_key_err(err_code);
  81                 break;
  82         }
  83         return rc;
  84 }
  85
  86 /**
  87  * ecryptfs_parse_packet_length
  88  * @data: Pointer to memory containing length at offset
  89  * @size: This function writes the decoded size to this memory
  90  *        address; zero on error
  91  * @length_size: The number of bytes occupied by the encoded length
  92  *
  93  * Returns zero on success; non-zero on error
  94  */
  95 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
  96                                  size_t *length_size)
  97 {
  98         int rc = 0;
  99
 100         (*length_size) = 0;
 101         (*size) = 0;
 102         if (data[0] < 192) {
 103                 /* One-byte length */
 104                 (*size) = data[0];
 105                 (*length_size) = 1;
 106         } else if (data[0] < 224) {
 107                 /* Two-byte length */
 108                 (*size) = (data[0] - 192) * 256;
 109                 (*size) += data[1] + 192;
 110                 (*length_size) = 2;
 111         } else if (data[0] == 255) {
 112                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
 113                 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
 114                                 "supported\n");
 115                 rc = -EINVAL;
 116                 goto out;
 117         } else {
 118                 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
 119                 rc = -EINVAL;
 120                 goto out;
 121         }
 122 out:
 123         return rc;
 124 }
 125
 126 /**
 127  * ecryptfs_write_packet_length
 128  * @dest: The byte array target into which to write the length. Must
 129  *        have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
 130  * @size: The length to write.
 131  * @packet_size_length: The number of bytes used to encode the packet
 132  *                      length is written to this address.
 133  *
 134  * Returns zero on success; non-zero on error.
 135  */
 136 int ecryptfs_write_packet_length(char *dest, size_t size,
 137                                  size_t *packet_size_length)
 138 {
 139         int rc = 0;
 140
 141         if (size < 192) {
 142                 dest[0] = size;
 143                 (*packet_size_length) = 1;
 144         } else if (size < 65536) {
 145                 dest[0] = (((size - 192) / 256) + 192);
 146                 dest[1] = ((size - 192) % 256);
 147                 (*packet_size_length) = 2;
 148         } else {
 149                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
 150                 rc = -EINVAL;
 151                 ecryptfs_printk(KERN_WARNING,
 152                                 "Unsupported packet size: [%zd]\n", size);
 153         }
 154         return rc;
 155 }
 156
 157 static int
 158 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
 159                     char **packet, size_t *packet_len)
 160 {
 161         size_t i = 0;
 162         size_t data_len;
 163         size_t packet_size_len;
 164         char *message;
 165         int rc;
 166
 167         /*
 168          *              ***** TAG 64 Packet Format *****
 169          *    | Content Type                       | 1 byte       |
 170          *    | Key Identifier Size                | 1 or 2 bytes |
 171          *    | Key Identifier                     | arbitrary    |
 172          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 173          *    | Encrypted File Encryption Key      | arbitrary    |
 174          */
 175         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
 176                     + session_key->encrypted_key_size);
 177         *packet = kmalloc(data_len, GFP_KERNEL);
 178         message = *packet;
 179         if (!message) {
 180                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 181                 rc = -ENOMEM;
 182                 goto out;
 183         }
 184         message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
 185         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 186                                           &packet_size_len);
 187         if (rc) {
 188                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 189                                 "header; cannot generate packet length\n");
 190                 goto out;
 191         }
 192         i += packet_size_len;
 193         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 194         i += ECRYPTFS_SIG_SIZE_HEX;
 195         rc = ecryptfs_write_packet_length(&message[i],
 196                                           session_key->encrypted_key_size,
 197                                           &packet_size_len);
 198         if (rc) {
 199                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
 200                                 "header; cannot generate packet length\n");
 201                 goto out;
 202         }
 203         i += packet_size_len;
 204         memcpy(&message[i], session_key->encrypted_key,
 205                session_key->encrypted_key_size);
 206         i += session_key->encrypted_key_size;
 207         *packet_len = i;
 208 out:
 209         return rc;
 210 }
 211
 212 static int
 213 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
 214                     struct ecryptfs_message *msg)
 215 {
 216         size_t i = 0;
 217         char *data;
 218         size_t data_len;
 219         size_t m_size;
 220         size_t message_len;
 221         u16 checksum = 0;
 222         u16 expected_checksum = 0;
 223         int rc;
 224
 225         /*
 226          *              ***** TAG 65 Packet Format *****
 227          *         | Content Type             | 1 byte       |
 228          *         | Status Indicator         | 1 byte       |
 229          *         | File Encryption Key Size | 1 or 2 bytes |
 230          *         | File Encryption Key      | arbitrary    |
 231          */
 232         message_len = msg->data_len;
 233         data = msg->data;
 234         if (message_len < 4) {
 235                 rc = -EIO;
 236                 goto out;
 237         }
 238         if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
 239                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
 240                 rc = -EIO;
 241                 goto out;
 242         }
 243         if (data[i++]) {
 244                 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
 245                                 "[%d]\n", data[i-1]);
 246                 rc = -EIO;
 247                 goto out;
 248         }
 249         rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
 250         if (rc) {
 251                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 252                                 "rc = [%d]\n", rc);
 253                 goto out;
 254         }
 255         i += data_len;
 256         if (message_len < (i + m_size)) {
 257                 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
 258                                 "is shorter than expected\n");
 259                 rc = -EIO;
 260                 goto out;
 261         }
 262         if (m_size < 3) {
 263                 ecryptfs_printk(KERN_ERR,
 264                                 "The decrypted key is not long enough to "
 265                                 "include a cipher code and checksum\n");
 266                 rc = -EIO;
 267                 goto out;
 268         }
 269         *cipher_code = data[i++];
 270         /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
 271         session_key->decrypted_key_size = m_size - 3;
 272         if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
 273                 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
 274                                 "the maximum key size [%d]\n",
 275                                 session_key->decrypted_key_size,
 276                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 277                 rc = -EIO;
 278                 goto out;
 279         }
 280         memcpy(session_key->decrypted_key, &data[i],
 281                session_key->decrypted_key_size);
 282         i += session_key->decrypted_key_size;
 283         expected_checksum += (unsigned char)(data[i++]) << 8;
 284         expected_checksum += (unsigned char)(data[i++]);
 285         for (i = 0; i < session_key->decrypted_key_size; i++)
 286                 checksum += session_key->decrypted_key[i];
 287         if (expected_checksum != checksum) {
 288                 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
 289                                 "encryption  key; expected [%x]; calculated "
 290                                 "[%x]\n", expected_checksum, checksum);
 291                 rc = -EIO;
 292         }
 293 out:
 294         return rc;
 295 }
 296
 297
 298 static int
 299 write_tag_66_packet(char *signature, u8 cipher_code,
 300                     struct ecryptfs_crypt_stat *crypt_stat, char **packet,
 301                     size_t *packet_len)
 302 {
 303         size_t i = 0;
 304         size_t j;
 305         size_t data_len;
 306         size_t checksum = 0;
 307         size_t packet_size_len;
 308         char *message;
 309         int rc;
 310
 311         /*
 312          *              ***** TAG 66 Packet Format *****
 313          *         | Content Type             | 1 byte       |
 314          *         | Key Identifier Size      | 1 or 2 bytes |
 315          *         | Key Identifier           | arbitrary    |
 316          *         | File Encryption Key Size | 1 or 2 bytes |
 317          *         | File Encryption Key      | arbitrary    |
 318          */
 319         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
 320         *packet = kmalloc(data_len, GFP_KERNEL);
 321         message = *packet;
 322         if (!message) {
 323                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
 324                 rc = -ENOMEM;
 325                 goto out;
 326         }
 327         message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
 328         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
 329                                           &packet_size_len);
 330         if (rc) {
 331                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 332                                 "header; cannot generate packet length\n");
 333                 goto out;
 334         }
 335         i += packet_size_len;
 336         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
 337         i += ECRYPTFS_SIG_SIZE_HEX;
 338         /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
 339         rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
 340                                           &packet_size_len);
 341         if (rc) {
 342                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
 343                                 "header; cannot generate packet length\n");
 344                 goto out;
 345         }
 346         i += packet_size_len;
 347         message[i++] = cipher_code;
 348         memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
 349         i += crypt_stat->key_size;
 350         for (j = 0; j < crypt_stat->key_size; j++)
 351                 checksum += crypt_stat->key[j];
 352         message[i++] = (checksum / 256) % 256;
 353         message[i++] = (checksum % 256);
 354         *packet_len = i;
 355 out:
 356         return rc;
 357 }
 358
 359 static int
 360 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
 361                     struct ecryptfs_message *msg)
 362 {
 363         size_t i = 0;
 364         char *data;
 365         size_t data_len;
 366         size_t message_len;
 367         int rc;
 368
 369         /*
 370          *              ***** TAG 65 Packet Format *****
 371          *    | Content Type                       | 1 byte       |
 372          *    | Status Indicator                   | 1 byte       |
 373          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
 374          *    | Encrypted File Encryption Key      | arbitrary    |
 375          */
 376         message_len = msg->data_len;
 377         data = msg->data;
 378         /* verify that everything through the encrypted FEK size is present */
 379         if (message_len < 4) {
 380                 rc = -EIO;
 381                 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
 382                        "message length is [%d]\n", __func__, message_len, 4);
 383                 goto out;
 384         }
 385         if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
 386                 rc = -EIO;
 387                 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
 388                        __func__);
 389                 goto out;
 390         }
 391         if (data[i++]) {
 392                 rc = -EIO;
 393                 printk(KERN_ERR "%s: Status indicator has non zero "
 394                        "value [%d]\n", __func__, data[i-1]);
 395
 396                 goto out;
 397         }
 398         rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
 399                                           &data_len);
 400         if (rc) {
 401                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
 402                                 "rc = [%d]\n", rc);
 403                 goto out;
 404         }
 405         i += data_len;
 406         if (message_len < (i + key_rec->enc_key_size)) {
 407                 rc = -EIO;
 408                 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
 409                        __func__, message_len, (i + key_rec->enc_key_size));
 410                 goto out;
 411         }
 412         if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
 413                 rc = -EIO;
 414                 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
 415                        "the maximum key size [%d]\n", __func__,
 416                        key_rec->enc_key_size,
 417                        ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
 418                 goto out;
 419         }
 420         memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
 421 out:
 422         return rc;
 423 }
 424
 425 /**
 426  * ecryptfs_verify_version
 427  * @version: The version number to confirm
 428  *
 429  * Returns zero on good version; non-zero otherwise
 430  */
 431 static int ecryptfs_verify_version(u16 version)
 432 {
 433         int rc = 0;
 434         unsigned char major;
 435         unsigned char minor;
 436
 437         major = ((version >> 8) & 0xFF);
 438         minor = (version & 0xFF);
 439         if (major != ECRYPTFS_VERSION_MAJOR) {
 440                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
 441                                 "Expected [%d]; got [%d]\n",
 442                                 ECRYPTFS_VERSION_MAJOR, major);
 443                 rc = -EINVAL;
 444                 goto out;
 445         }
 446         if (minor != ECRYPTFS_VERSION_MINOR) {
 447                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
 448                                 "Expected [%d]; got [%d]\n",
 449                                 ECRYPTFS_VERSION_MINOR, minor);
 450                 rc = -EINVAL;
 451                 goto out;
 452         }
 453 out:
 454         return rc;
 455 }
 456
 457 /**
 458  * ecryptfs_verify_auth_tok_from_key
 459  * @auth_tok_key: key containing the authentication token
 460  * @auth_tok: authentication token
 461  *
 462  * Returns zero on valid auth tok; -EINVAL otherwise
 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 (ecryptfs_verify_version((*auth_tok)->version)) {
 472                 printk(KERN_ERR "Data structure version mismatch. Userspace "
 473                        "tools must match eCryptfs kernel module with major "
 474                        "version [%d] and minor version [%d]\n",
 475                        ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
 476                 rc = -EINVAL;
 477                 goto out;
 478         }
 479         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
 480             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
 481                 printk(KERN_ERR "Invalid auth_tok structure "
 482                        "returned from key query\n");
 483                 rc = -EINVAL;
 484                 goto out;
 485         }
 486 out:
 487         return rc;
 488 }
 489
 490 static int
 491 ecryptfs_find_global_auth_tok_for_sig(
 492         struct key **auth_tok_key,
 493         struct ecryptfs_auth_tok **auth_tok,
 494         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
 495 {
 496         struct ecryptfs_global_auth_tok *walker;
 497         int rc = 0;
 498
 499         (*auth_tok_key) = NULL;
 500         (*auth_tok) = NULL;
 501         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 502         list_for_each_entry(walker,
 503                             &mount_crypt_stat->global_auth_tok_list,
 504                             mount_crypt_stat_list) {
 505                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
 506                         continue;
 507
 508                 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
 509                         rc = -EINVAL;
 510                         goto out;
 511                 }
 512
 513                 rc = key_validate(walker->global_auth_tok_key);
 514                 if (rc) {
 515                         if (rc == -EKEYEXPIRED)
 516                                 goto out;
 517                         goto out_invalid_auth_tok;
 518                 }
 519
 520                 down_write(&(walker->global_auth_tok_key->sem));
 521                 rc = ecryptfs_verify_auth_tok_from_key(
 522                                 walker->global_auth_tok_key, auth_tok);
 523                 if (rc)
 524                         goto out_invalid_auth_tok_unlock;
 525
 526                 (*auth_tok_key) = walker->global_auth_tok_key;
 527                 key_get(*auth_tok_key);
 528                 goto out;
 529         }
 530         rc = -ENOENT;
 531         goto out;
 532 out_invalid_auth_tok_unlock:
 533         up_write(&(walker->global_auth_tok_key->sem));
 534 out_invalid_auth_tok:
 535         printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
 536         walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 537         key_put(walker->global_auth_tok_key);
 538         walker->global_auth_tok_key = NULL;
 539 out:
 540         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 541         return rc;
 542 }
 543
 544 /**
 545  * ecryptfs_find_auth_tok_for_sig
 546  * @auth_tok: Set to the matching auth_tok; NULL if not found
 547  * @crypt_stat: inode crypt_stat crypto context
 548  * @sig: Sig of auth_tok to find
 549  *
 550  * For now, this function simply looks at the registered auth_tok's
 551  * linked off the mount_crypt_stat, so all the auth_toks that can be
 552  * used must be registered at mount time. This function could
 553  * potentially try a lot harder to find auth_tok's (e.g., by calling
 554  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
 555  * that static registration of auth_tok's will no longer be necessary.
 556  *
 557  * Returns zero on no error; non-zero on error
 558  */
 559 static int
 560 ecryptfs_find_auth_tok_for_sig(
 561         struct key **auth_tok_key,
 562         struct ecryptfs_auth_tok **auth_tok,
 563         struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 564         char *sig)
 565 {
 566         int rc = 0;
 567
 568         rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
 569                                                    mount_crypt_stat, sig);
 570         if (rc == -ENOENT) {
 571                 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
 572                  * mount_crypt_stat structure, we prevent to use auth toks that
 573                  * are not inserted through the ecryptfs_add_global_auth_tok
 574                  * function.
 575                  */
 576                 if (mount_crypt_stat->flags
 577                                 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
 578                         return -EINVAL;
 579
 580                 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
 581                                                        sig);
 582         }
 583         return rc;
 584 }
 585
 586 /**
 587  * write_tag_70_packet can gobble a lot of stack space. We stuff most
 588  * of the function's parameters in a kmalloc'd struct to help reduce
 589  * eCryptfs' overall stack usage.
 590  */
 591 struct ecryptfs_write_tag_70_packet_silly_stack {
 592         u8 cipher_code;
 593         size_t max_packet_size;
 594         size_t packet_size_len;
 595         size_t block_aligned_filename_size;
 596         size_t block_size;
 597         size_t i;
 598         size_t j;
 599         size_t num_rand_bytes;
 600         struct mutex *tfm_mutex;
 601         char *block_aligned_filename;
 602         struct ecryptfs_auth_tok *auth_tok;
 603         struct scatterlist src_sg[2];
 604         struct scatterlist dst_sg[2];
 605         struct crypto_skcipher *skcipher_tfm;
 606         struct skcipher_request *skcipher_req;
 607         char iv[ECRYPTFS_MAX_IV_BYTES];
 608         char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 609         char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 610         struct crypto_shash *hash_tfm;
 611         struct shash_desc *hash_desc;
 612 };
 613
 614 /**
 615  * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
 616  * @filename: NULL-terminated filename string
 617  *
 618  * This is the simplest mechanism for achieving filename encryption in
 619  * eCryptfs. It encrypts the given filename with the mount-wide
 620  * filename encryption key (FNEK) and stores it in a packet to @dest,
 621  * which the callee will encode and write directly into the dentry
 622  * name.
 623  */
 624 int
 625 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
 626                              size_t *packet_size,
 627                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 628                              char *filename, size_t filename_size)
 629 {
 630         struct ecryptfs_write_tag_70_packet_silly_stack *s;
 631         struct key *auth_tok_key = NULL;
 632         int rc = 0;
 633
 634         s = kzalloc(sizeof(*s), GFP_KERNEL);
 635         if (!s) {
 636                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 637                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 638                 rc = -ENOMEM;
 639                 goto out;
 640         }
 641         (*packet_size) = 0;
 642         rc = ecryptfs_find_auth_tok_for_sig(
 643                 &auth_tok_key,
 644                 &s->auth_tok, mount_crypt_stat,
 645                 mount_crypt_stat->global_default_fnek_sig);
 646         if (rc) {
 647                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 648                        "fnek sig [%s]; rc = [%d]\n", __func__,
 649                        mount_crypt_stat->global_default_fnek_sig, rc);
 650                 goto out;
 651         }
 652         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
 653                 &s->skcipher_tfm,
 654                 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
 655         if (unlikely(rc)) {
 656                 printk(KERN_ERR "Internal error whilst attempting to get "
 657                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
 658                        mount_crypt_stat->global_default_fn_cipher_name, rc);
 659                 goto out;
 660         }
 661         mutex_lock(s->tfm_mutex);
 662         s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
 663         /* Plus one for the \0 separator between the random prefix
 664          * and the plaintext filename */
 665         s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
 666         s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
 667         if ((s->block_aligned_filename_size % s->block_size) != 0) {
 668                 s->num_rand_bytes += (s->block_size
 669                                       - (s->block_aligned_filename_size
 670                                          % s->block_size));
 671                 s->block_aligned_filename_size = (s->num_rand_bytes
 672                                                   + filename_size);
 673         }
 674         /* Octet 0: Tag 70 identifier
 675          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 676          *              and block-aligned encrypted filename size)
 677          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 678          * Octet N2-N3: Cipher identifier (1 octet)
 679          * Octets N3-N4: Block-aligned encrypted filename
 680          *  - Consists of a minimum number of random characters, a \0
 681          *    separator, and then the filename */
 682         s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
 683                               + s->block_aligned_filename_size);
 684         if (dest == NULL) {
 685                 (*packet_size) = s->max_packet_size;
 686                 goto out_unlock;
 687         }
 688         if (s->max_packet_size > (*remaining_bytes)) {
 689                 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
 690                        "[%zd] available\n", __func__, s->max_packet_size,
 691                        (*remaining_bytes));
 692                 rc = -EINVAL;
 693                 goto out_unlock;
 694         }
 695
 696         s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
 697         if (!s->skcipher_req) {
 698                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 699                        "skcipher_request_alloc for %s\n", __func__,
 700                        crypto_skcipher_driver_name(s->skcipher_tfm));
 701                 rc = -ENOMEM;
 702                 goto out_unlock;
 703         }
 704
 705         skcipher_request_set_callback(s->skcipher_req,
 706                                       CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
 707
 708         s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
 709                                             GFP_KERNEL);
 710         if (!s->block_aligned_filename) {
 711                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 712                        "kzalloc [%zd] bytes\n", __func__,
 713                        s->block_aligned_filename_size);
 714                 rc = -ENOMEM;
 715                 goto out_unlock;
 716         }
 717         dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
 718         rc = ecryptfs_write_packet_length(&dest[s->i],
 719                                           (ECRYPTFS_SIG_SIZE
 720                                            + 1 /* Cipher code */
 721                                            + s->block_aligned_filename_size),
 722                                           &s->packet_size_len);
 723         if (rc) {
 724                 printk(KERN_ERR "%s: Error generating tag 70 packet "
 725                        "header; cannot generate packet length; rc = [%d]\n",
 726                        __func__, rc);
 727                 goto out_free_unlock;
 728         }
 729         s->i += s->packet_size_len;
 730         ecryptfs_from_hex(&dest[s->i],
 731                           mount_crypt_stat->global_default_fnek_sig,
 732                           ECRYPTFS_SIG_SIZE);
 733         s->i += ECRYPTFS_SIG_SIZE;
 734         s->cipher_code = ecryptfs_code_for_cipher_string(
 735                 mount_crypt_stat->global_default_fn_cipher_name,
 736                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 737         if (s->cipher_code == 0) {
 738                 printk(KERN_WARNING "%s: Unable to generate code for "
 739                        "cipher [%s] with key bytes [%zd]\n", __func__,
 740                        mount_crypt_stat->global_default_fn_cipher_name,
 741                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 742                 rc = -EINVAL;
 743                 goto out_free_unlock;
 744         }
 745         dest[s->i++] = s->cipher_code;
 746         /* TODO: Support other key modules than passphrase for
 747          * filename encryption */
 748         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
 749                 rc = -EOPNOTSUPP;
 750                 printk(KERN_INFO "%s: Filename encryption only supports "
 751                        "password tokens\n", __func__);
 752                 goto out_free_unlock;
 753         }
 754         s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
 755         if (IS_ERR(s->hash_tfm)) {
 756                         rc = PTR_ERR(s->hash_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
 763         s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
 764                                crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
 765         if (!s->hash_desc) {
 766                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 767                        "kmalloc [%zd] bytes\n", __func__,
 768                        sizeof(*s->hash_desc) +
 769                        crypto_shash_descsize(s->hash_tfm));
 770                 rc = -ENOMEM;
 771                 goto out_release_free_unlock;
 772         }
 773
 774         s->hash_desc->tfm = s->hash_tfm;
 775         s->hash_desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 776
 777         rc = crypto_shash_digest(s->hash_desc,
 778                                  (u8 *)s->auth_tok->token.password.session_key_encryption_key,
 779                                  s->auth_tok->token.password.session_key_encryption_key_bytes,
 780                                  s->hash);
 781         if (rc) {
 782                 printk(KERN_ERR
 783                        "%s: Error computing crypto hash; rc = [%d]\n",
 784                        __func__, rc);
 785                 goto out_release_free_unlock;
 786         }
 787         for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
 788                 s->block_aligned_filename[s->j] =
 789                         s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
 790                 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
 791                     == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
 792                         rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
 793                                                 ECRYPTFS_TAG_70_DIGEST_SIZE,
 794                                                 s->tmp_hash);
 795                         if (rc) {
 796                                 printk(KERN_ERR
 797                                        "%s: Error computing crypto hash; "
 798                                        "rc = [%d]\n", __func__, rc);
 799                                 goto out_release_free_unlock;
 800                         }
 801                         memcpy(s->hash, s->tmp_hash,
 802                                ECRYPTFS_TAG_70_DIGEST_SIZE);
 803                 }
 804                 if (s->block_aligned_filename[s->j] == '\0')
 805                         s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
 806         }
 807         memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
 808                filename_size);
 809         rc = virt_to_scatterlist(s->block_aligned_filename,
 810                                  s->block_aligned_filename_size, s->src_sg, 2);
 811         if (rc < 1) {
 812                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 813                        "convert filename memory to scatterlist; rc = [%d]. "
 814                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 815                        s->block_aligned_filename_size);
 816                 goto out_release_free_unlock;
 817         }
 818         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
 819                                  s->dst_sg, 2);
 820         if (rc < 1) {
 821                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 822                        "convert encrypted filename memory to scatterlist; "
 823                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
 824                        __func__, rc, s->block_aligned_filename_size);
 825                 goto out_release_free_unlock;
 826         }
 827         /* The characters in the first block effectively do the job
 828          * of the IV here, so we just use 0's for the IV. Note the
 829          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
 830          * >= ECRYPTFS_MAX_IV_BYTES. */
 831         rc = crypto_skcipher_setkey(
 832                 s->skcipher_tfm,
 833                 s->auth_tok->token.password.session_key_encryption_key,
 834                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 835         if (rc < 0) {
 836                 printk(KERN_ERR "%s: Error setting key for crypto context; "
 837                        "rc = [%d]. s->auth_tok->token.password.session_key_"
 838                        "encryption_key = [0x%p]; mount_crypt_stat->"
 839                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
 840                        rc,
 841                        s->auth_tok->token.password.session_key_encryption_key,
 842                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 843                 goto out_release_free_unlock;
 844         }
 845         skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
 846                                    s->block_aligned_filename_size, s->iv);
 847         rc = crypto_skcipher_encrypt(s->skcipher_req);
 848         if (rc) {
 849                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
 850                        "rc = [%d]\n", __func__, rc);
 851                 goto out_release_free_unlock;
 852         }
 853         s->i += s->block_aligned_filename_size;
 854         (*packet_size) = s->i;
 855         (*remaining_bytes) -= (*packet_size);
 856 out_release_free_unlock:
 857         crypto_free_shash(s->hash_tfm);
 858 out_free_unlock:
 859         kzfree(s->block_aligned_filename);
 860 out_unlock:
 861         mutex_unlock(s->tfm_mutex);
 862 out:
 863         if (auth_tok_key) {
 864                 up_write(&(auth_tok_key->sem));
 865                 key_put(auth_tok_key);
 866         }
 867         skcipher_request_free(s->skcipher_req);
 868         kzfree(s->hash_desc);
 869         kfree(s);
 870         return rc;
 871 }
 872
 873 struct ecryptfs_parse_tag_70_packet_silly_stack {
 874         u8 cipher_code;
 875         size_t max_packet_size;
 876         size_t packet_size_len;
 877         size_t parsed_tag_70_packet_size;
 878         size_t block_aligned_filename_size;
 879         size_t block_size;
 880         size_t i;
 881         struct mutex *tfm_mutex;
 882         char *decrypted_filename;
 883         struct ecryptfs_auth_tok *auth_tok;
 884         struct scatterlist src_sg[2];
 885         struct scatterlist dst_sg[2];
 886         struct crypto_skcipher *skcipher_tfm;
 887         struct skcipher_request *skcipher_req;
 888         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
 889         char iv[ECRYPTFS_MAX_IV_BYTES];
 890         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
 891 };
 892
 893 /**
 894  * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
 895  * @filename: This function kmalloc's the memory for the filename
 896  * @filename_size: This function sets this to the amount of memory
 897  *                 kmalloc'd for the filename
 898  * @packet_size: This function sets this to the the number of octets
 899  *               in the packet parsed
 900  * @mount_crypt_stat: The mount-wide cryptographic context
 901  * @data: The memory location containing the start of the tag 70
 902  *        packet
 903  * @max_packet_size: The maximum legal size of the packet to be parsed
 904  *                   from @data
 905  *
 906  * Returns zero on success; non-zero otherwise
 907  */
 908 int
 909 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
 910                              size_t *packet_size,
 911                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 912                              char *data, size_t max_packet_size)
 913 {
 914         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
 915         struct key *auth_tok_key = NULL;
 916         int rc = 0;
 917
 918         (*packet_size) = 0;
 919         (*filename_size) = 0;
 920         (*filename) = NULL;
 921         s = kzalloc(sizeof(*s), GFP_KERNEL);
 922         if (!s) {
 923                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 924                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 925                 rc = -ENOMEM;
 926                 goto out;
 927         }
 928         if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
 929                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
 930                        "at least [%d]\n", __func__, max_packet_size,
 931                        ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
 932                 rc = -EINVAL;
 933                 goto out;
 934         }
 935         /* Octet 0: Tag 70 identifier
 936          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 937          *              and block-aligned encrypted filename size)
 938          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 939          * Octet N2-N3: Cipher identifier (1 octet)
 940          * Octets N3-N4: Block-aligned encrypted filename
 941          *  - Consists of a minimum number of random numbers, a \0
 942          *    separator, and then the filename */
 943         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
 944                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
 945                        "tag [0x%.2x]\n", __func__,
 946                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
 947                 rc = -EINVAL;
 948                 goto out;
 949         }
 950         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
 951                                           &s->parsed_tag_70_packet_size,
 952                                           &s->packet_size_len);
 953         if (rc) {
 954                 printk(KERN_WARNING "%s: Error parsing packet length; "
 955                        "rc = [%d]\n", __func__, rc);
 956                 goto out;
 957         }
 958         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
 959                                           - ECRYPTFS_SIG_SIZE - 1);
 960         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
 961             > max_packet_size) {
 962                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
 963                        "size is [%zd]\n", __func__, max_packet_size,
 964                        (1 + s->packet_size_len + 1
 965                         + s->block_aligned_filename_size));
 966                 rc = -EINVAL;
 967                 goto out;
 968         }
 969         (*packet_size) += s->packet_size_len;
 970         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
 971                         ECRYPTFS_SIG_SIZE);
 972         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 973         (*packet_size) += ECRYPTFS_SIG_SIZE;
 974         s->cipher_code = data[(*packet_size)++];
 975         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
 976         if (rc) {
 977                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
 978                        __func__, s->cipher_code);
 979                 goto out;
 980         }
 981         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
 982                                             &s->auth_tok, mount_crypt_stat,
 983                                             s->fnek_sig_hex);
 984         if (rc) {
 985                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 986                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
 987                        rc);
 988                 goto out;
 989         }
 990         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
 991                                                         &s->tfm_mutex,
 992                                                         s->cipher_string);
 993         if (unlikely(rc)) {
 994                 printk(KERN_ERR "Internal error whilst attempting to get "
 995                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
 996                        s->cipher_string, rc);
 997                 goto out;
 998         }
 999         mutex_lock(s->tfm_mutex);
1000         rc = virt_to_scatterlist(&data[(*packet_size)],
1001                                  s->block_aligned_filename_size, s->src_sg, 2);
1002         if (rc < 1) {
1003                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1004                        "convert encrypted filename memory to scatterlist; "
1005                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1006                        __func__, rc, s->block_aligned_filename_size);
1007                 goto out_unlock;
1008         }
1009         (*packet_size) += s->block_aligned_filename_size;
1010         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1011                                         GFP_KERNEL);
1012         if (!s->decrypted_filename) {
1013                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1014                        "kmalloc [%zd] bytes\n", __func__,
1015                        s->block_aligned_filename_size);
1016                 rc = -ENOMEM;
1017                 goto out_unlock;
1018         }
1019         rc = virt_to_scatterlist(s->decrypted_filename,
1020                                  s->block_aligned_filename_size, s->dst_sg, 2);
1021         if (rc < 1) {
1022                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1023                        "convert decrypted filename memory to scatterlist; "
1024                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1025                        __func__, rc, s->block_aligned_filename_size);
1026                 goto out_free_unlock;
1027         }
1028
1029         s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1030         if (!s->skcipher_req) {
1031                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1032                        "skcipher_request_alloc for %s\n", __func__,
1033                        crypto_skcipher_driver_name(s->skcipher_tfm));
1034                 rc = -ENOMEM;
1035                 goto out_free_unlock;
1036         }
1037
1038         skcipher_request_set_callback(s->skcipher_req,
1039                                       CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1040
1041         /* The characters in the first block effectively do the job of
1042          * the IV here, so we just use 0's for the IV. Note the
1043          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1044          * >= ECRYPTFS_MAX_IV_BYTES. */
1045         /* TODO: Support other key modules than passphrase for
1046          * filename encryption */
1047         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1048                 rc = -EOPNOTSUPP;
1049                 printk(KERN_INFO "%s: Filename encryption only supports "
1050                        "password tokens\n", __func__);
1051                 goto out_free_unlock;
1052         }
1053         rc = crypto_skcipher_setkey(
1054                 s->skcipher_tfm,
1055                 s->auth_tok->token.password.session_key_encryption_key,
1056                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1057         if (rc < 0) {
1058                 printk(KERN_ERR "%s: Error setting key for crypto context; "
1059                        "rc = [%d]. s->auth_tok->token.password.session_key_"
1060                        "encryption_key = [0x%p]; mount_crypt_stat->"
1061                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1062                        rc,
1063                        s->auth_tok->token.password.session_key_encryption_key,
1064                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
1065                 goto out_free_unlock;
1066         }
1067         skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1068                                    s->block_aligned_filename_size, s->iv);
1069         rc = crypto_skcipher_decrypt(s->skcipher_req);
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         while (s->decrypted_filename[s->i] != '\0'
1076                && s->i < s->block_aligned_filename_size)
1077                 s->i++;
1078         if (s->i == s->block_aligned_filename_size) {
1079                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1080                        "find valid separator between random characters and "
1081                        "the filename\n", __func__);
1082                 rc = -EINVAL;
1083                 goto out_free_unlock;
1084         }
1085         s->i++;
1086         (*filename_size) = (s->block_aligned_filename_size - s->i);
1087         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1088                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1089                        "invalid\n", __func__, (*filename_size));
1090                 rc = -EINVAL;
1091                 goto out_free_unlock;
1092         }
1093         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1094         if (!(*filename)) {
1095                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1096                        "kmalloc [%zd] bytes\n", __func__,
1097                        ((*filename_size) + 1));
1098                 rc = -ENOMEM;
1099                 goto out_free_unlock;
1100         }
1101         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1102         (*filename)[(*filename_size)] = '\0';
1103 out_free_unlock:
1104         kfree(s->decrypted_filename);
1105 out_unlock:
1106         mutex_unlock(s->tfm_mutex);
1107 out:
1108         if (rc) {
1109                 (*packet_size) = 0;
1110                 (*filename_size) = 0;
1111                 (*filename) = NULL;
1112         }
1113         if (auth_tok_key) {
1114                 up_write(&(auth_tok_key->sem));
1115                 key_put(auth_tok_key);
1116         }
1117         skcipher_request_free(s->skcipher_req);
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;
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 crypto_skcipher *tfm;
1678         struct skcipher_request *req = NULL;
1679         int rc = 0;
1680
1681         if (unlikely(ecryptfs_verbosity > 0)) {
1682                 ecryptfs_printk(
1683                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1684                         auth_tok->token.password.session_key_encryption_key_bytes);
1685                 ecryptfs_dump_hex(
1686                         auth_tok->token.password.session_key_encryption_key,
1687                         auth_tok->token.password.session_key_encryption_key_bytes);
1688         }
1689         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1690                                                         crypt_stat->cipher);
1691         if (unlikely(rc)) {
1692                 printk(KERN_ERR "Internal error whilst attempting to get "
1693                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1694                        crypt_stat->cipher, rc);
1695                 goto out;
1696         }
1697         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1698                                  auth_tok->session_key.encrypted_key_size,
1699                                  src_sg, 2);
1700         if (rc < 1 || rc > 2) {
1701                 printk(KERN_ERR "Internal error whilst attempting to convert "
1702                         "auth_tok->session_key.encrypted_key to scatterlist; "
1703                         "expected rc = 1; got rc = [%d]. "
1704                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1705                         auth_tok->session_key.encrypted_key_size);
1706                 goto out;
1707         }
1708         auth_tok->session_key.decrypted_key_size =
1709                 auth_tok->session_key.encrypted_key_size;
1710         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1711                                  auth_tok->session_key.decrypted_key_size,
1712                                  dst_sg, 2);
1713         if (rc < 1 || rc > 2) {
1714                 printk(KERN_ERR "Internal error whilst attempting to convert "
1715                         "auth_tok->session_key.decrypted_key to scatterlist; "
1716                         "expected rc = 1; got rc = [%d]\n", rc);
1717                 goto out;
1718         }
1719         mutex_lock(tfm_mutex);
1720         req = skcipher_request_alloc(tfm, GFP_KERNEL);
1721         if (!req) {
1722                 mutex_unlock(tfm_mutex);
1723                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1724                        "skcipher_request_alloc for %s\n", __func__,
1725                        crypto_skcipher_driver_name(tfm));
1726                 rc = -ENOMEM;
1727                 goto out;
1728         }
1729
1730         skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1731                                       NULL, NULL);
1732         rc = crypto_skcipher_setkey(
1733                 tfm, auth_tok->token.password.session_key_encryption_key,
1734                 crypt_stat->key_size);
1735         if (unlikely(rc < 0)) {
1736                 mutex_unlock(tfm_mutex);
1737                 printk(KERN_ERR "Error setting key for crypto context\n");
1738                 rc = -EINVAL;
1739                 goto out;
1740         }
1741         skcipher_request_set_crypt(req, src_sg, dst_sg,
1742                                    auth_tok->session_key.encrypted_key_size,
1743                                    NULL);
1744         rc = crypto_skcipher_decrypt(req);
1745         mutex_unlock(tfm_mutex);
1746         if (unlikely(rc)) {
1747                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1748                 goto out;
1749         }
1750         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1751         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1752                auth_tok->session_key.decrypted_key_size);
1753         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1754         if (unlikely(ecryptfs_verbosity > 0)) {
1755                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1756                                 crypt_stat->key_size);
1757                 ecryptfs_dump_hex(crypt_stat->key,
1758                                   crypt_stat->key_size);
1759         }
1760 out:
1761         skcipher_request_free(req);
1762         return rc;
1763 }
1764
1765 /**
1766  * ecryptfs_parse_packet_set
1767  * @crypt_stat: The cryptographic context
1768  * @src: Virtual address of region of memory containing the packets
1769  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1770  *
1771  * Get crypt_stat to have the file's session key if the requisite key
1772  * is available to decrypt the session key.
1773  *
1774  * Returns Zero if a valid authentication token was retrieved and
1775  * processed; negative value for file not encrypted or for error
1776  * conditions.
1777  */
1778 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1779                               unsigned char *src,
1780                               struct dentry *ecryptfs_dentry)
1781 {
1782         size_t i = 0;
1783         size_t found_auth_tok;
1784         size_t next_packet_is_auth_tok_packet;
1785         struct list_head auth_tok_list;
1786         struct ecryptfs_auth_tok *matching_auth_tok;
1787         struct ecryptfs_auth_tok *candidate_auth_tok;
1788         char *candidate_auth_tok_sig;
1789         size_t packet_size;
1790         struct ecryptfs_auth_tok *new_auth_tok;
1791         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1792         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1793         size_t tag_11_contents_size;
1794         size_t tag_11_packet_size;
1795         struct key *auth_tok_key = NULL;
1796         int rc = 0;
1797
1798         INIT_LIST_HEAD(&auth_tok_list);
1799         /* Parse the header to find as many packets as we can; these will be
1800          * added the our &auth_tok_list */
1801         next_packet_is_auth_tok_packet = 1;
1802         while (next_packet_is_auth_tok_packet) {
1803                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1804
1805                 switch (src[i]) {
1806                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1807                         rc = parse_tag_3_packet(crypt_stat,
1808                                                 (unsigned char *)&src[i],
1809                                                 &auth_tok_list, &new_auth_tok,
1810                                                 &packet_size, max_packet_size);
1811                         if (rc) {
1812                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1813                                                 "tag 3 packet\n");
1814                                 rc = -EIO;
1815                                 goto out_wipe_list;
1816                         }
1817                         i += packet_size;
1818                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1819                                                  sig_tmp_space,
1820                                                  ECRYPTFS_SIG_SIZE,
1821                                                  &tag_11_contents_size,
1822                                                  &tag_11_packet_size,
1823                                                  max_packet_size);
1824                         if (rc) {
1825                                 ecryptfs_printk(KERN_ERR, "No valid "
1826                                                 "(ecryptfs-specific) literal "
1827                                                 "packet containing "
1828                                                 "authentication token "
1829                                                 "signature found after "
1830                                                 "tag 3 packet\n");
1831                                 rc = -EIO;
1832                                 goto out_wipe_list;
1833                         }
1834                         i += tag_11_packet_size;
1835                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1836                                 ecryptfs_printk(KERN_ERR, "Expected "
1837                                                 "signature of size [%d]; "
1838                                                 "read size [%zd]\n",
1839                                                 ECRYPTFS_SIG_SIZE,
1840                                                 tag_11_contents_size);
1841                                 rc = -EIO;
1842                                 goto out_wipe_list;
1843                         }
1844                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1845                                         sig_tmp_space, tag_11_contents_size);
1846                         new_auth_tok->token.password.signature[
1847                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1848                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1849                         break;
1850                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1851                         rc = parse_tag_1_packet(crypt_stat,
1852                                                 (unsigned char *)&src[i],
1853                                                 &auth_tok_list, &new_auth_tok,
1854                                                 &packet_size, max_packet_size);
1855                         if (rc) {
1856                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1857                                                 "tag 1 packet\n");
1858                                 rc = -EIO;
1859                                 goto out_wipe_list;
1860                         }
1861                         i += packet_size;
1862                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1863                         break;
1864                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1865                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1866                                         "(Tag 11 not allowed by itself)\n");
1867                         rc = -EIO;
1868                         goto out_wipe_list;
1869                 default:
1870                         ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1871                                         "of the file header; hex value of "
1872                                         "character is [0x%.2x]\n", i, src[i]);
1873                         next_packet_is_auth_tok_packet = 0;
1874                 }
1875         }
1876         if (list_empty(&auth_tok_list)) {
1877                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1878                        "eCryptfs file; this is not supported in this version "
1879                        "of the eCryptfs kernel module\n");
1880                 rc = -EINVAL;
1881                 goto out;
1882         }
1883         /* auth_tok_list contains the set of authentication tokens
1884          * parsed from the metadata. We need to find a matching
1885          * authentication token that has the secret component(s)
1886          * necessary to decrypt the EFEK in the auth_tok parsed from
1887          * the metadata. There may be several potential matches, but
1888          * just one will be sufficient to decrypt to get the FEK. */
1889 find_next_matching_auth_tok:
1890         found_auth_tok = 0;
1891         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1892                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1893                 if (unlikely(ecryptfs_verbosity > 0)) {
1894                         ecryptfs_printk(KERN_DEBUG,
1895                                         "Considering cadidate auth tok:\n");
1896                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1897                 }
1898                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1899                                                candidate_auth_tok);
1900                 if (rc) {
1901                         printk(KERN_ERR
1902                                "Unrecognized candidate auth tok type: [%d]\n",
1903                                candidate_auth_tok->token_type);
1904                         rc = -EINVAL;
1905                         goto out_wipe_list;
1906                 }
1907                 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1908                                                &matching_auth_tok,
1909                                                crypt_stat->mount_crypt_stat,
1910                                                candidate_auth_tok_sig);
1911                 if (!rc) {
1912                         found_auth_tok = 1;
1913                         goto found_matching_auth_tok;
1914                 }
1915         }
1916         if (!found_auth_tok) {
1917                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1918                                 "authentication token\n");
1919                 rc = -EIO;
1920                 goto out_wipe_list;
1921         }
1922 found_matching_auth_tok:
1923         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1924                 memcpy(&(candidate_auth_tok->token.private_key),
1925                        &(matching_auth_tok->token.private_key),
1926                        sizeof(struct ecryptfs_private_key));
1927                 up_write(&(auth_tok_key->sem));
1928                 key_put(auth_tok_key);
1929                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1930                                                        crypt_stat);
1931         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1932                 memcpy(&(candidate_auth_tok->token.password),
1933                        &(matching_auth_tok->token.password),
1934                        sizeof(struct ecryptfs_password));
1935                 up_write(&(auth_tok_key->sem));
1936                 key_put(auth_tok_key);
1937                 rc = decrypt_passphrase_encrypted_session_key(
1938                         candidate_auth_tok, crypt_stat);
1939         } else {
1940                 up_write(&(auth_tok_key->sem));
1941                 key_put(auth_tok_key);
1942                 rc = -EINVAL;
1943         }
1944         if (rc) {
1945                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1946
1947                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1948                                 "session key for authentication token with sig "
1949                                 "[%.*s]; rc = [%d]. Removing auth tok "
1950                                 "candidate from the list and searching for "
1951                                 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1952                                 candidate_auth_tok_sig, rc);
1953                 list_for_each_entry_safe(auth_tok_list_item,
1954                                          auth_tok_list_item_tmp,
1955                                          &auth_tok_list, list) {
1956                         if (candidate_auth_tok
1957                             == &auth_tok_list_item->auth_tok) {
1958                                 list_del(&auth_tok_list_item->list);
1959                                 kmem_cache_free(
1960                                         ecryptfs_auth_tok_list_item_cache,
1961                                         auth_tok_list_item);
1962                                 goto find_next_matching_auth_tok;
1963                         }
1964                 }
1965                 BUG();
1966         }
1967         rc = ecryptfs_compute_root_iv(crypt_stat);
1968         if (rc) {
1969                 ecryptfs_printk(KERN_ERR, "Error computing "
1970                                 "the root IV\n");
1971                 goto out_wipe_list;
1972         }
1973         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1974         if (rc) {
1975                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1976                                 "context for cipher [%s]; rc = [%d]\n",
1977                                 crypt_stat->cipher, rc);
1978         }
1979 out_wipe_list:
1980         wipe_auth_tok_list(&auth_tok_list);
1981 out:
1982         return rc;
1983 }
1984
1985 static int
1986 pki_encrypt_session_key(struct key *auth_tok_key,
1987                         struct ecryptfs_auth_tok *auth_tok,
1988                         struct ecryptfs_crypt_stat *crypt_stat,
1989                         struct ecryptfs_key_record *key_rec)
1990 {
1991         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1992         char *payload = NULL;
1993         size_t payload_len = 0;
1994         struct ecryptfs_message *msg;
1995         int rc;
1996
1997         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1998                                  ecryptfs_code_for_cipher_string(
1999                                          crypt_stat->cipher,
2000                                          crypt_stat->key_size),
2001                                  crypt_stat, &payload, &payload_len);
2002         up_write(&(auth_tok_key->sem));
2003         key_put(auth_tok_key);
2004         if (rc) {
2005                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
2006                 goto out;
2007         }
2008         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
2009         if (rc) {
2010                 ecryptfs_printk(KERN_ERR, "Error sending message to "
2011                                 "ecryptfsd: %d\n", rc);
2012                 goto out;
2013         }
2014         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
2015         if (rc) {
2016                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
2017                                 "from the user space daemon\n");
2018                 rc = -EIO;
2019                 goto out;
2020         }
2021         rc = parse_tag_67_packet(key_rec, msg);
2022         if (rc)
2023                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2024         kfree(msg);
2025 out:
2026         kfree(payload);
2027         return rc;
2028 }
2029 /**
2030  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2031  * @dest: Buffer into which to write the packet
2032  * @remaining_bytes: Maximum number of bytes that can be writtn
2033  * @auth_tok_key: The authentication token key to unlock and put when done with
2034  *                @auth_tok
2035  * @auth_tok: The authentication token used for generating the tag 1 packet
2036  * @crypt_stat: The cryptographic context
2037  * @key_rec: The key record struct for the tag 1 packet
2038  * @packet_size: This function will write the number of bytes that end
2039  *               up constituting the packet; set to zero on error
2040  *
2041  * Returns zero on success; non-zero on error.
2042  */
2043 static int
2044 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2045                    struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2046                    struct ecryptfs_crypt_stat *crypt_stat,
2047                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2048 {
2049         size_t i;
2050         size_t encrypted_session_key_valid = 0;
2051         size_t packet_size_length;
2052         size_t max_packet_size;
2053         int rc = 0;
2054
2055         (*packet_size) = 0;
2056         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2057                           ECRYPTFS_SIG_SIZE);
2058         encrypted_session_key_valid = 0;
2059         for (i = 0; i < crypt_stat->key_size; i++)
2060                 encrypted_session_key_valid |=
2061                         auth_tok->session_key.encrypted_key[i];
2062         if (encrypted_session_key_valid) {
2063                 memcpy(key_rec->enc_key,
2064                        auth_tok->session_key.encrypted_key,
2065                        auth_tok->session_key.encrypted_key_size);
2066                 up_write(&(auth_tok_key->sem));
2067                 key_put(auth_tok_key);
2068                 goto encrypted_session_key_set;
2069         }
2070         if (auth_tok->session_key.encrypted_key_size == 0)
2071                 auth_tok->session_key.encrypted_key_size =
2072                         auth_tok->token.private_key.key_size;
2073         rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2074                                      key_rec);
2075         if (rc) {
2076                 printk(KERN_ERR "Failed to encrypt session key via a key "
2077                        "module; rc = [%d]\n", rc);
2078                 goto out;
2079         }
2080         if (ecryptfs_verbosity > 0) {
2081                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2082                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2083         }
2084 encrypted_session_key_set:
2085         /* This format is inspired by OpenPGP; see RFC 2440
2086          * packet tag 1 */
2087         max_packet_size = (1                         /* Tag 1 identifier */
2088                            + 3                       /* Max Tag 1 packet size */
2089                            + 1                       /* Version */
2090                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
2091                            + 1                       /* Cipher identifier */
2092                            + key_rec->enc_key_size); /* Encrypted key size */
2093         if (max_packet_size > (*remaining_bytes)) {
2094                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2095                        "need up to [%td] bytes, but there are only [%td] "
2096                        "available\n", max_packet_size, (*remaining_bytes));
2097                 rc = -EINVAL;
2098                 goto out;
2099         }
2100         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2101         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2102                                           (max_packet_size - 4),
2103                                           &packet_size_length);
2104         if (rc) {
2105                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2106                                 "header; cannot generate packet length\n");
2107                 goto out;
2108         }
2109         (*packet_size) += packet_size_length;
2110         dest[(*packet_size)++] = 0x03; /* version 3 */
2111         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2112         (*packet_size) += ECRYPTFS_SIG_SIZE;
2113         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2114         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2115                key_rec->enc_key_size);
2116         (*packet_size) += key_rec->enc_key_size;
2117 out:
2118         if (rc)
2119                 (*packet_size) = 0;
2120         else
2121                 (*remaining_bytes) -= (*packet_size);
2122         return rc;
2123 }
2124
2125 /**
2126  * write_tag_11_packet
2127  * @dest: Target into which Tag 11 packet is to be written
2128  * @remaining_bytes: Maximum packet length
2129  * @contents: Byte array of contents to copy in
2130  * @contents_length: Number of bytes in contents
2131  * @packet_length: Length of the Tag 11 packet written; zero on error
2132  *
2133  * Returns zero on success; non-zero on error.
2134  */
2135 static int
2136 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2137                     size_t contents_length, size_t *packet_length)
2138 {
2139         size_t packet_size_length;
2140         size_t max_packet_size;
2141         int rc = 0;
2142
2143         (*packet_length) = 0;
2144         /* This format is inspired by OpenPGP; see RFC 2440
2145          * packet tag 11 */
2146         max_packet_size = (1                   /* Tag 11 identifier */
2147                            + 3                 /* Max Tag 11 packet size */
2148                            + 1                 /* Binary format specifier */
2149                            + 1                 /* Filename length */
2150                            + 8                 /* Filename ("_CONSOLE") */
2151                            + 4                 /* Modification date */
2152                            + contents_length); /* Literal data */
2153         if (max_packet_size > (*remaining_bytes)) {
2154                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2155                        "need up to [%td] bytes, but there are only [%td] "
2156                        "available\n", max_packet_size, (*remaining_bytes));
2157                 rc = -EINVAL;
2158                 goto out;
2159         }
2160         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2161         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2162                                           (max_packet_size - 4),
2163                                           &packet_size_length);
2164         if (rc) {
2165                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2166                        "generate packet length. rc = [%d]\n", rc);
2167                 goto out;
2168         }
2169         (*packet_length) += packet_size_length;
2170         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2171         dest[(*packet_length)++] = 8;
2172         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2173         (*packet_length) += 8;
2174         memset(&dest[(*packet_length)], 0x00, 4);
2175         (*packet_length) += 4;
2176         memcpy(&dest[(*packet_length)], contents, contents_length);
2177         (*packet_length) += contents_length;
2178  out:
2179         if (rc)
2180                 (*packet_length) = 0;
2181         else
2182                 (*remaining_bytes) -= (*packet_length);
2183         return rc;
2184 }
2185
2186 /**
2187  * write_tag_3_packet
2188  * @dest: Buffer into which to write the packet
2189  * @remaining_bytes: Maximum number of bytes that can be written
2190  * @auth_tok: Authentication token
2191  * @crypt_stat: The cryptographic context
2192  * @key_rec: encrypted key
2193  * @packet_size: This function will write the number of bytes that end
2194  *               up constituting the packet; set to zero on error
2195  *
2196  * Returns zero on success; non-zero on error.
2197  */
2198 static int
2199 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2200                    struct ecryptfs_auth_tok *auth_tok,
2201                    struct ecryptfs_crypt_stat *crypt_stat,
2202                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2203 {
2204         size_t i;
2205         size_t encrypted_session_key_valid = 0;
2206         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2207         struct scatterlist dst_sg[2];
2208         struct scatterlist src_sg[2];
2209         struct mutex *tfm_mutex = NULL;
2210         u8 cipher_code;
2211         size_t packet_size_length;
2212         size_t max_packet_size;
2213         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2214                 crypt_stat->mount_crypt_stat;
2215         struct crypto_skcipher *tfm;
2216         struct skcipher_request *req;
2217         int rc = 0;
2218
2219         (*packet_size) = 0;
2220         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2221                           ECRYPTFS_SIG_SIZE);
2222         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2223                                                         crypt_stat->cipher);
2224         if (unlikely(rc)) {
2225                 printk(KERN_ERR "Internal error whilst attempting to get "
2226                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2227                        crypt_stat->cipher, rc);
2228                 goto out;
2229         }
2230         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2231                 printk(KERN_WARNING "No key size specified at mount; "
2232                        "defaulting to [%d]\n",
2233                        crypto_skcipher_default_keysize(tfm));
2234                 mount_crypt_stat->global_default_cipher_key_size =
2235                         crypto_skcipher_default_keysize(tfm);
2236         }
2237         if (crypt_stat->key_size == 0)
2238                 crypt_stat->key_size =
2239                         mount_crypt_stat->global_default_cipher_key_size;
2240         if (auth_tok->session_key.encrypted_key_size == 0)
2241                 auth_tok->session_key.encrypted_key_size =
2242                         crypt_stat->key_size;
2243         if (crypt_stat->key_size == 24
2244             && strcmp("aes", crypt_stat->cipher) == 0) {
2245                 memset((crypt_stat->key + 24), 0, 8);
2246                 auth_tok->session_key.encrypted_key_size = 32;
2247         } else
2248                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2249         key_rec->enc_key_size =
2250                 auth_tok->session_key.encrypted_key_size;
2251         encrypted_session_key_valid = 0;
2252         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2253                 encrypted_session_key_valid |=
2254                         auth_tok->session_key.encrypted_key[i];
2255         if (encrypted_session_key_valid) {
2256                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2257                                 "using auth_tok->session_key.encrypted_key, "
2258                                 "where key_rec->enc_key_size = [%zd]\n",
2259                                 key_rec->enc_key_size);
2260                 memcpy(key_rec->enc_key,
2261                        auth_tok->session_key.encrypted_key,
2262                        key_rec->enc_key_size);
2263                 goto encrypted_session_key_set;
2264         }
2265         if (auth_tok->token.password.flags &
2266             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2267                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2268                                 "session key encryption key of size [%d]\n",
2269                                 auth_tok->token.password.
2270                                 session_key_encryption_key_bytes);
2271                 memcpy(session_key_encryption_key,
2272                        auth_tok->token.password.session_key_encryption_key,
2273                        crypt_stat->key_size);
2274                 ecryptfs_printk(KERN_DEBUG,
2275                                 "Cached session key encryption key:\n");
2276                 if (ecryptfs_verbosity > 0)
2277                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2278         }
2279         if (unlikely(ecryptfs_verbosity > 0)) {
2280                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2281                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2282         }
2283         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2284                                  src_sg, 2);
2285         if (rc < 1 || rc > 2) {
2286                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2287                                 "for crypt_stat session key; expected rc = 1; "
2288                                 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2289                                 rc, key_rec->enc_key_size);
2290                 rc = -ENOMEM;
2291                 goto out;
2292         }
2293         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2294                                  dst_sg, 2);
2295         if (rc < 1 || rc > 2) {
2296                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2297                                 "for crypt_stat encrypted session key; "
2298                                 "expected rc = 1; got rc = [%d]. "
2299                                 "key_rec->enc_key_size = [%zd]\n", rc,
2300                                 key_rec->enc_key_size);
2301                 rc = -ENOMEM;
2302                 goto out;
2303         }
2304         mutex_lock(tfm_mutex);
2305         rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2306                                     crypt_stat->key_size);
2307         if (rc < 0) {
2308                 mutex_unlock(tfm_mutex);
2309                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2310                                 "context; rc = [%d]\n", rc);
2311                 goto out;
2312         }
2313
2314         req = skcipher_request_alloc(tfm, GFP_KERNEL);
2315         if (!req) {
2316                 mutex_unlock(tfm_mutex);
2317                 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2318                                 "attempting to skcipher_request_alloc for "
2319                                 "%s\n", crypto_skcipher_driver_name(tfm));
2320                 rc = -ENOMEM;
2321                 goto out;
2322         }
2323
2324         skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2325                                       NULL, NULL);
2326
2327         rc = 0;
2328         ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2329                         crypt_stat->key_size);
2330         skcipher_request_set_crypt(req, src_sg, dst_sg,
2331                                    (*key_rec).enc_key_size, NULL);
2332         rc = crypto_skcipher_encrypt(req);
2333         mutex_unlock(tfm_mutex);
2334         skcipher_request_free(req);
2335         if (rc) {
2336                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2337                 goto out;
2338         }
2339         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2340         if (ecryptfs_verbosity > 0) {
2341                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2342                                 key_rec->enc_key_size);
2343                 ecryptfs_dump_hex(key_rec->enc_key,
2344                                   key_rec->enc_key_size);
2345         }
2346 encrypted_session_key_set:
2347         /* This format is inspired by OpenPGP; see RFC 2440
2348          * packet tag 3 */
2349         max_packet_size = (1                         /* Tag 3 identifier */
2350                            + 3                       /* Max Tag 3 packet size */
2351                            + 1                       /* Version */
2352                            + 1                       /* Cipher code */
2353                            + 1                       /* S2K specifier */
2354                            + 1                       /* Hash identifier */
2355                            + ECRYPTFS_SALT_SIZE      /* Salt */
2356                            + 1                       /* Hash iterations */
2357                            + key_rec->enc_key_size); /* Encrypted key size */
2358         if (max_packet_size > (*remaining_bytes)) {
2359                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2360                        "there are only [%td] available\n", max_packet_size,
2361                        (*remaining_bytes));
2362                 rc = -EINVAL;
2363                 goto out;
2364         }
2365         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2366         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2367          * to get the number of octets in the actual Tag 3 packet */
2368         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2369                                           (max_packet_size - 4),
2370                                           &packet_size_length);
2371         if (rc) {
2372                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2373                        "generate packet length. rc = [%d]\n", rc);
2374                 goto out;
2375         }
2376         (*packet_size) += packet_size_length;
2377         dest[(*packet_size)++] = 0x04; /* version 4 */
2378         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2379          * specified with strings */
2380         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2381                                                       crypt_stat->key_size);
2382         if (cipher_code == 0) {
2383                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2384                                 "cipher [%s]\n", crypt_stat->cipher);
2385                 rc = -EINVAL;
2386                 goto out;
2387         }
2388         dest[(*packet_size)++] = cipher_code;
2389         dest[(*packet_size)++] = 0x03;  /* S2K */
2390         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2391         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2392                ECRYPTFS_SALT_SIZE);
2393         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2394         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2395         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2396                key_rec->enc_key_size);
2397         (*packet_size) += key_rec->enc_key_size;
2398 out:
2399         if (rc)
2400                 (*packet_size) = 0;
2401         else
2402                 (*remaining_bytes) -= (*packet_size);
2403         return rc;
2404 }
2405
2406 struct kmem_cache *ecryptfs_key_record_cache;
2407
2408 /**
2409  * ecryptfs_generate_key_packet_set
2410  * @dest_base: Virtual address from which to write the key record set
2411  * @crypt_stat: The cryptographic context from which the
2412  *              authentication tokens will be retrieved
2413  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2414  *                   for the global parameters
2415  * @len: The amount written
2416  * @max: The maximum amount of data allowed to be written
2417  *
2418  * Generates a key packet set and writes it to the virtual address
2419  * passed in.
2420  *
2421  * Returns zero on success; non-zero on error.
2422  */
2423 int
2424 ecryptfs_generate_key_packet_set(char *dest_base,
2425                                  struct ecryptfs_crypt_stat *crypt_stat,
2426                                  struct dentry *ecryptfs_dentry, size_t *len,
2427                                  size_t max)
2428 {
2429         struct ecryptfs_auth_tok *auth_tok;
2430         struct key *auth_tok_key = NULL;
2431         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2432                 &ecryptfs_superblock_to_private(
2433                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2434         size_t written;
2435         struct ecryptfs_key_record *key_rec;
2436         struct ecryptfs_key_sig *key_sig;
2437         int rc = 0;
2438
2439         (*len) = 0;
2440         mutex_lock(&crypt_stat->keysig_list_mutex);
2441         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2442         if (!key_rec) {
2443                 rc = -ENOMEM;
2444                 goto out;
2445         }
2446         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2447                             crypt_stat_list) {
2448                 memset(key_rec, 0, sizeof(*key_rec));
2449                 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2450                                                            &auth_tok,
2451                                                            mount_crypt_stat,
2452                                                            key_sig->keysig);
2453                 if (rc) {
2454                         printk(KERN_WARNING "Unable to retrieve auth tok with "
2455                                "sig = [%s]\n", key_sig->keysig);
2456                         rc = process_find_global_auth_tok_for_sig_err(rc);
2457                         goto out_free;
2458                 }
2459                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2460                         rc = write_tag_3_packet((dest_base + (*len)),
2461                                                 &max, auth_tok,
2462                                                 crypt_stat, key_rec,
2463                                                 &written);
2464                         up_write(&(auth_tok_key->sem));
2465                         key_put(auth_tok_key);
2466                         if (rc) {
2467                                 ecryptfs_printk(KERN_WARNING, "Error "
2468                                                 "writing tag 3 packet\n");
2469                                 goto out_free;
2470                         }
2471                         (*len) += written;
2472                         /* Write auth tok signature packet */
2473                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2474                                                  key_rec->sig,
2475                                                  ECRYPTFS_SIG_SIZE, &written);
2476                         if (rc) {
2477                                 ecryptfs_printk(KERN_ERR, "Error writing "
2478                                                 "auth tok signature packet\n");
2479                                 goto out_free;
2480                         }
2481                         (*len) += written;
2482                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2483                         rc = write_tag_1_packet(dest_base + (*len), &max,
2484                                                 auth_tok_key, auth_tok,
2485                                                 crypt_stat, key_rec, &written);
2486                         if (rc) {
2487                                 ecryptfs_printk(KERN_WARNING, "Error "
2488                                                 "writing tag 1 packet\n");
2489                                 goto out_free;
2490                         }
2491                         (*len) += written;
2492                 } else {
2493                         up_write(&(auth_tok_key->sem));
2494                         key_put(auth_tok_key);
2495                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2496                                         "authentication token type\n");
2497                         rc = -EINVAL;
2498                         goto out_free;
2499                 }
2500         }
2501         if (likely(max > 0)) {
2502                 dest_base[(*len)] = 0x00;
2503         } else {
2504                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2505                 rc = -EIO;
2506         }
2507 out_free:
2508         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2509 out:
2510         if (rc)
2511                 (*len) = 0;
2512         mutex_unlock(&crypt_stat->keysig_list_mutex);
2513         return rc;
2514 }
2515
2516 struct kmem_cache *ecryptfs_key_sig_cache;
2517
2518 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2519 {
2520         struct ecryptfs_key_sig *new_key_sig;
2521
2522         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2523         if (!new_key_sig) {
2524                 printk(KERN_ERR
2525                        "Error allocating from ecryptfs_key_sig_cache\n");
2526                 return -ENOMEM;
2527         }
2528         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2529         new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2530         /* Caller must hold keysig_list_mutex */
2531         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2532
2533         return 0;
2534 }
2535
2536 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2537
2538 int
2539 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2540                              char *sig, u32 global_auth_tok_flags)
2541 {
2542         struct ecryptfs_global_auth_tok *new_auth_tok;
2543         int rc = 0;
2544
2545         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2546                                         GFP_KERNEL);
2547         if (!new_auth_tok) {
2548                 rc = -ENOMEM;
2549                 printk(KERN_ERR "Error allocating from "
2550                        "ecryptfs_global_auth_tok_cache\n");
2551                 goto out;
2552         }
2553         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2554         new_auth_tok->flags = global_auth_tok_flags;
2555         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2556         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2557         list_add(&new_auth_tok->mount_crypt_stat_list,
2558                  &mount_crypt_stat->global_auth_tok_list);
2559         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2560 out:
2561         return rc;
2562 }
2563