fs/ecryptfs/keystore.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  * In-kernel key management code.  Includes functions to parse and
   4  * write authentication token-related packets with the underlying
   5  * file.
   6  *
   7  * Copyright (C) 2004-2006 International Business Machines Corp.
   8  *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
   9  *              Michael C. Thompson <mcthomps@us.ibm.com>
  10  *              Trevor S. Highland <trevor.highland@gmail.com>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  25  * 02111-1307, USA.
  26  */
  27
  28 #include <linux/string.h>
  29 #include <linux/syscalls.h>
  30 #include <linux/pagemap.h>
  31 #include <linux/key.h>
  32 #include <linux/random.h>
  33 #include <linux/crypto.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) = (unsigned char)data[0];
 105                 (*length_size) = 1;
 106         } else if (data[0] < 224) {
 107                 /* Two-byte length */
 108                 (*size) = (((unsigned char)(data[0]) - 192) * 256);
 109                 (*size) += ((unsigned char)(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 blkcipher_desc desc;
 606         char iv[ECRYPTFS_MAX_IV_BYTES];
 607         char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 608         char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
 609         struct hash_desc hash_desc;
 610         struct scatterlist hash_sg;
 611 };
 612
 613 /**
 614  * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
 615  * @filename: NULL-terminated filename string
 616  *
 617  * This is the simplest mechanism for achieving filename encryption in
 618  * eCryptfs. It encrypts the given filename with the mount-wide
 619  * filename encryption key (FNEK) and stores it in a packet to @dest,
 620  * which the callee will encode and write directly into the dentry
 621  * name.
 622  */
 623 int
 624 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
 625                              size_t *packet_size,
 626                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 627                              char *filename, size_t filename_size)
 628 {
 629         struct ecryptfs_write_tag_70_packet_silly_stack *s;
 630         struct key *auth_tok_key = NULL;
 631         int rc = 0;
 632
 633         s = kmalloc(sizeof(*s), GFP_KERNEL);
 634         if (!s) {
 635                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 636                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 637                 rc = -ENOMEM;
 638                 goto out;
 639         }
 640         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 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->desc.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_blkcipher_blocksize(s->desc.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         s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
 696                                             GFP_KERNEL);
 697         if (!s->block_aligned_filename) {
 698                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
 699                        "kzalloc [%zd] bytes\n", __func__,
 700                        s->block_aligned_filename_size);
 701                 rc = -ENOMEM;
 702                 goto out_unlock;
 703         }
 704         s->i = 0;
 705         dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
 706         rc = ecryptfs_write_packet_length(&dest[s->i],
 707                                           (ECRYPTFS_SIG_SIZE
 708                                            + 1 /* Cipher code */
 709                                            + s->block_aligned_filename_size),
 710                                           &s->packet_size_len);
 711         if (rc) {
 712                 printk(KERN_ERR "%s: Error generating tag 70 packet "
 713                        "header; cannot generate packet length; rc = [%d]\n",
 714                        __func__, rc);
 715                 goto out_free_unlock;
 716         }
 717         s->i += s->packet_size_len;
 718         ecryptfs_from_hex(&dest[s->i],
 719                           mount_crypt_stat->global_default_fnek_sig,
 720                           ECRYPTFS_SIG_SIZE);
 721         s->i += ECRYPTFS_SIG_SIZE;
 722         s->cipher_code = ecryptfs_code_for_cipher_string(
 723                 mount_crypt_stat->global_default_fn_cipher_name,
 724                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 725         if (s->cipher_code == 0) {
 726                 printk(KERN_WARNING "%s: Unable to generate code for "
 727                        "cipher [%s] with key bytes [%zd]\n", __func__,
 728                        mount_crypt_stat->global_default_fn_cipher_name,
 729                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 730                 rc = -EINVAL;
 731                 goto out_free_unlock;
 732         }
 733         dest[s->i++] = s->cipher_code;
 734         /* TODO: Support other key modules than passphrase for
 735          * filename encryption */
 736         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
 737                 rc = -EOPNOTSUPP;
 738                 printk(KERN_INFO "%s: Filename encryption only supports "
 739                        "password tokens\n", __func__);
 740                 goto out_free_unlock;
 741         }
 742         sg_init_one(
 743                 &s->hash_sg,
 744                 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
 745                 s->auth_tok->token.password.session_key_encryption_key_bytes);
 746         s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 747         s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
 748                                              CRYPTO_ALG_ASYNC);
 749         if (IS_ERR(s->hash_desc.tfm)) {
 750                         rc = PTR_ERR(s->hash_desc.tfm);
 751                         printk(KERN_ERR "%s: Error attempting to "
 752                                "allocate hash crypto context; rc = [%d]\n",
 753                                __func__, rc);
 754                         goto out_free_unlock;
 755         }
 756         rc = crypto_hash_init(&s->hash_desc);
 757         if (rc) {
 758                 printk(KERN_ERR
 759                        "%s: Error initializing crypto hash; rc = [%d]\n",
 760                        __func__, rc);
 761                 goto out_release_free_unlock;
 762         }
 763         rc = crypto_hash_update(
 764                 &s->hash_desc, &s->hash_sg,
 765                 s->auth_tok->token.password.session_key_encryption_key_bytes);
 766         if (rc) {
 767                 printk(KERN_ERR
 768                        "%s: Error updating crypto hash; rc = [%d]\n",
 769                        __func__, rc);
 770                 goto out_release_free_unlock;
 771         }
 772         rc = crypto_hash_final(&s->hash_desc, s->hash);
 773         if (rc) {
 774                 printk(KERN_ERR
 775                        "%s: Error finalizing crypto hash; rc = [%d]\n",
 776                        __func__, rc);
 777                 goto out_release_free_unlock;
 778         }
 779         for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
 780                 s->block_aligned_filename[s->j] =
 781                         s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
 782                 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
 783                     == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
 784                         sg_init_one(&s->hash_sg, (u8 *)s->hash,
 785                                     ECRYPTFS_TAG_70_DIGEST_SIZE);
 786                         rc = crypto_hash_init(&s->hash_desc);
 787                         if (rc) {
 788                                 printk(KERN_ERR
 789                                        "%s: Error initializing crypto hash; "
 790                                        "rc = [%d]\n", __func__, rc);
 791                                 goto out_release_free_unlock;
 792                         }
 793                         rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
 794                                                 ECRYPTFS_TAG_70_DIGEST_SIZE);
 795                         if (rc) {
 796                                 printk(KERN_ERR
 797                                        "%s: Error updating crypto hash; "
 798                                        "rc = [%d]\n", __func__, rc);
 799                                 goto out_release_free_unlock;
 800                         }
 801                         rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
 802                         if (rc) {
 803                                 printk(KERN_ERR
 804                                        "%s: Error finalizing crypto hash; "
 805                                        "rc = [%d]\n", __func__, rc);
 806                                 goto out_release_free_unlock;
 807                         }
 808                         memcpy(s->hash, s->tmp_hash,
 809                                ECRYPTFS_TAG_70_DIGEST_SIZE);
 810                 }
 811                 if (s->block_aligned_filename[s->j] == '\0')
 812                         s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
 813         }
 814         memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
 815                filename_size);
 816         rc = virt_to_scatterlist(s->block_aligned_filename,
 817                                  s->block_aligned_filename_size, s->src_sg, 2);
 818         if (rc < 1) {
 819                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 820                        "convert filename memory to scatterlist; rc = [%d]. "
 821                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 822                        s->block_aligned_filename_size);
 823                 goto out_release_free_unlock;
 824         }
 825         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
 826                                  s->dst_sg, 2);
 827         if (rc < 1) {
 828                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 829                        "convert encrypted filename memory to scatterlist; "
 830                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
 831                        __func__, rc, s->block_aligned_filename_size);
 832                 goto out_release_free_unlock;
 833         }
 834         /* The characters in the first block effectively do the job
 835          * of the IV here, so we just use 0's for the IV. Note the
 836          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
 837          * >= ECRYPTFS_MAX_IV_BYTES. */
 838         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
 839         s->desc.info = s->iv;
 840         rc = crypto_blkcipher_setkey(
 841                 s->desc.tfm,
 842                 s->auth_tok->token.password.session_key_encryption_key,
 843                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 844         if (rc < 0) {
 845                 printk(KERN_ERR "%s: Error setting key for crypto context; "
 846                        "rc = [%d]. s->auth_tok->token.password.session_key_"
 847                        "encryption_key = [0x%p]; mount_crypt_stat->"
 848                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
 849                        rc,
 850                        s->auth_tok->token.password.session_key_encryption_key,
 851                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 852                 goto out_release_free_unlock;
 853         }
 854         rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
 855                                          s->block_aligned_filename_size);
 856         if (rc) {
 857                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
 858                        "rc = [%d]\n", __func__, rc);
 859                 goto out_release_free_unlock;
 860         }
 861         s->i += s->block_aligned_filename_size;
 862         (*packet_size) = s->i;
 863         (*remaining_bytes) -= (*packet_size);
 864 out_release_free_unlock:
 865         crypto_free_hash(s->hash_desc.tfm);
 866 out_free_unlock:
 867         kzfree(s->block_aligned_filename);
 868 out_unlock:
 869         mutex_unlock(s->tfm_mutex);
 870 out:
 871         if (auth_tok_key) {
 872                 up_write(&(auth_tok_key->sem));
 873                 key_put(auth_tok_key);
 874         }
 875         kfree(s);
 876         return rc;
 877 }
 878
 879 struct ecryptfs_parse_tag_70_packet_silly_stack {
 880         u8 cipher_code;
 881         size_t max_packet_size;
 882         size_t packet_size_len;
 883         size_t parsed_tag_70_packet_size;
 884         size_t block_aligned_filename_size;
 885         size_t block_size;
 886         size_t i;
 887         struct mutex *tfm_mutex;
 888         char *decrypted_filename;
 889         struct ecryptfs_auth_tok *auth_tok;
 890         struct scatterlist src_sg[2];
 891         struct scatterlist dst_sg[2];
 892         struct blkcipher_desc desc;
 893         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
 894         char iv[ECRYPTFS_MAX_IV_BYTES];
 895         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
 896 };
 897
 898 /**
 899  * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
 900  * @filename: This function kmalloc's the memory for the filename
 901  * @filename_size: This function sets this to the amount of memory
 902  *                 kmalloc'd for the filename
 903  * @packet_size: This function sets this to the the number of octets
 904  *               in the packet parsed
 905  * @mount_crypt_stat: The mount-wide cryptographic context
 906  * @data: The memory location containing the start of the tag 70
 907  *        packet
 908  * @max_packet_size: The maximum legal size of the packet to be parsed
 909  *                   from @data
 910  *
 911  * Returns zero on success; non-zero otherwise
 912  */
 913 int
 914 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
 915                              size_t *packet_size,
 916                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 917                              char *data, size_t max_packet_size)
 918 {
 919         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
 920         struct key *auth_tok_key = NULL;
 921         int rc = 0;
 922
 923         (*packet_size) = 0;
 924         (*filename_size) = 0;
 925         (*filename) = NULL;
 926         s = kmalloc(sizeof(*s), GFP_KERNEL);
 927         if (!s) {
 928                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 929                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 930                 rc = -ENOMEM;
 931                 goto out;
 932         }
 933         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 934         if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
 935                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
 936                        "at least [%d]\n", __func__, max_packet_size,
 937                        ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
 938                 rc = -EINVAL;
 939                 goto out;
 940         }
 941         /* Octet 0: Tag 70 identifier
 942          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 943          *              and block-aligned encrypted filename size)
 944          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 945          * Octet N2-N3: Cipher identifier (1 octet)
 946          * Octets N3-N4: Block-aligned encrypted filename
 947          *  - Consists of a minimum number of random numbers, a \0
 948          *    separator, and then the filename */
 949         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
 950                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
 951                        "tag [0x%.2x]\n", __func__,
 952                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
 953                 rc = -EINVAL;
 954                 goto out;
 955         }
 956         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
 957                                           &s->parsed_tag_70_packet_size,
 958                                           &s->packet_size_len);
 959         if (rc) {
 960                 printk(KERN_WARNING "%s: Error parsing packet length; "
 961                        "rc = [%d]\n", __func__, rc);
 962                 goto out;
 963         }
 964         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
 965                                           - ECRYPTFS_SIG_SIZE - 1);
 966         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
 967             > max_packet_size) {
 968                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
 969                        "size is [%zd]\n", __func__, max_packet_size,
 970                        (1 + s->packet_size_len + 1
 971                         + s->block_aligned_filename_size));
 972                 rc = -EINVAL;
 973                 goto out;
 974         }
 975         (*packet_size) += s->packet_size_len;
 976         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
 977                         ECRYPTFS_SIG_SIZE);
 978         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 979         (*packet_size) += ECRYPTFS_SIG_SIZE;
 980         s->cipher_code = data[(*packet_size)++];
 981         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
 982         if (rc) {
 983                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
 984                        __func__, s->cipher_code);
 985                 goto out;
 986         }
 987         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
 988                                             &s->auth_tok, mount_crypt_stat,
 989                                             s->fnek_sig_hex);
 990         if (rc) {
 991                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 992                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
 993                        rc);
 994                 goto out;
 995         }
 996         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
 997                                                         &s->tfm_mutex,
 998                                                         s->cipher_string);
 999         if (unlikely(rc)) {
1000                 printk(KERN_ERR "Internal error whilst attempting to get "
1001                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1002                        s->cipher_string, rc);
1003                 goto out;
1004         }
1005         mutex_lock(s->tfm_mutex);
1006         rc = virt_to_scatterlist(&data[(*packet_size)],
1007                                  s->block_aligned_filename_size, s->src_sg, 2);
1008         if (rc < 1) {
1009                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1010                        "convert encrypted filename memory to scatterlist; "
1011                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1012                        __func__, rc, s->block_aligned_filename_size);
1013                 goto out_unlock;
1014         }
1015         (*packet_size) += s->block_aligned_filename_size;
1016         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1017                                         GFP_KERNEL);
1018         if (!s->decrypted_filename) {
1019                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1020                        "kmalloc [%zd] bytes\n", __func__,
1021                        s->block_aligned_filename_size);
1022                 rc = -ENOMEM;
1023                 goto out_unlock;
1024         }
1025         rc = virt_to_scatterlist(s->decrypted_filename,
1026                                  s->block_aligned_filename_size, s->dst_sg, 2);
1027         if (rc < 1) {
1028                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1029                        "convert decrypted filename memory to scatterlist; "
1030                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1031                        __func__, rc, s->block_aligned_filename_size);
1032                 goto out_free_unlock;
1033         }
1034         /* The characters in the first block effectively do the job of
1035          * the IV here, so we just use 0's for the IV. Note the
1036          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1037          * >= ECRYPTFS_MAX_IV_BYTES. */
1038         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1039         s->desc.info = s->iv;
1040         /* TODO: Support other key modules than passphrase for
1041          * filename encryption */
1042         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1043                 rc = -EOPNOTSUPP;
1044                 printk(KERN_INFO "%s: Filename encryption only supports "
1045                        "password tokens\n", __func__);
1046                 goto out_free_unlock;
1047         }
1048         rc = crypto_blkcipher_setkey(
1049                 s->desc.tfm,
1050                 s->auth_tok->token.password.session_key_encryption_key,
1051                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1052         if (rc < 0) {
1053                 printk(KERN_ERR "%s: Error setting key for crypto context; "
1054                        "rc = [%d]. s->auth_tok->token.password.session_key_"
1055                        "encryption_key = [0x%p]; mount_crypt_stat->"
1056                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1057                        rc,
1058                        s->auth_tok->token.password.session_key_encryption_key,
1059                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
1060                 goto out_free_unlock;
1061         }
1062         rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1063                                          s->block_aligned_filename_size);
1064         if (rc) {
1065                 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1066                        "rc = [%d]\n", __func__, rc);
1067                 goto out_free_unlock;
1068         }
1069         s->i = 0;
1070         while (s->decrypted_filename[s->i] != '\0'
1071                && s->i < s->block_aligned_filename_size)
1072                 s->i++;
1073         if (s->i == s->block_aligned_filename_size) {
1074                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1075                        "find valid separator between random characters and "
1076                        "the filename\n", __func__);
1077                 rc = -EINVAL;
1078                 goto out_free_unlock;
1079         }
1080         s->i++;
1081         (*filename_size) = (s->block_aligned_filename_size - s->i);
1082         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1083                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1084                        "invalid\n", __func__, (*filename_size));
1085                 rc = -EINVAL;
1086                 goto out_free_unlock;
1087         }
1088         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1089         if (!(*filename)) {
1090                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1091                        "kmalloc [%zd] bytes\n", __func__,
1092                        ((*filename_size) + 1));
1093                 rc = -ENOMEM;
1094                 goto out_free_unlock;
1095         }
1096         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1097         (*filename)[(*filename_size)] = '\0';
1098 out_free_unlock:
1099         kfree(s->decrypted_filename);
1100 out_unlock:
1101         mutex_unlock(s->tfm_mutex);
1102 out:
1103         if (rc) {
1104                 (*packet_size) = 0;
1105                 (*filename_size) = 0;
1106                 (*filename) = NULL;
1107         }
1108         if (auth_tok_key) {
1109                 up_write(&(auth_tok_key->sem));
1110                 key_put(auth_tok_key);
1111         }
1112         kfree(s);
1113         return rc;
1114 }
1115
1116 static int
1117 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1118 {
1119         int rc = 0;
1120
1121         (*sig) = NULL;
1122         switch (auth_tok->token_type) {
1123         case ECRYPTFS_PASSWORD:
1124                 (*sig) = auth_tok->token.password.signature;
1125                 break;
1126         case ECRYPTFS_PRIVATE_KEY:
1127                 (*sig) = auth_tok->token.private_key.signature;
1128                 break;
1129         default:
1130                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1131                        auth_tok->token_type);
1132                 rc = -EINVAL;
1133         }
1134         return rc;
1135 }
1136
1137 /**
1138  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1139  * @auth_tok: The key authentication token used to decrypt the session key
1140  * @crypt_stat: The cryptographic context
1141  *
1142  * Returns zero on success; non-zero error otherwise.
1143  */
1144 static int
1145 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1146                                   struct ecryptfs_crypt_stat *crypt_stat)
1147 {
1148         u8 cipher_code = 0;
1149         struct ecryptfs_msg_ctx *msg_ctx;
1150         struct ecryptfs_message *msg = NULL;
1151         char *auth_tok_sig;
1152         char *payload;
1153         size_t payload_len;
1154         int rc;
1155
1156         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1157         if (rc) {
1158                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1159                        auth_tok->token_type);
1160                 goto out;
1161         }
1162         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1163                                  &payload, &payload_len);
1164         if (rc) {
1165                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1166                 goto out;
1167         }
1168         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1169         if (rc) {
1170                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1171                                 "ecryptfsd\n");
1172                 goto out;
1173         }
1174         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1175         if (rc) {
1176                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1177                                 "from the user space daemon\n");
1178                 rc = -EIO;
1179                 goto out;
1180         }
1181         rc = parse_tag_65_packet(&(auth_tok->session_key),
1182                                  &cipher_code, msg);
1183         if (rc) {
1184                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1185                        rc);
1186                 goto out;
1187         }
1188         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1189         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1190                auth_tok->session_key.decrypted_key_size);
1191         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1192         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1193         if (rc) {
1194                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1195                                 cipher_code)
1196                 goto out;
1197         }
1198         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1199         if (ecryptfs_verbosity > 0) {
1200                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1201                 ecryptfs_dump_hex(crypt_stat->key,
1202                                   crypt_stat->key_size);
1203         }
1204 out:
1205         if (msg)
1206                 kfree(msg);
1207         return rc;
1208 }
1209
1210 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1211 {
1212         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1213         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1214
1215         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1216                                  auth_tok_list_head, list) {
1217                 list_del(&auth_tok_list_item->list);
1218                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1219                                 auth_tok_list_item);
1220         }
1221 }
1222
1223 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1224
1225 /**
1226  * parse_tag_1_packet
1227  * @crypt_stat: The cryptographic context to modify based on packet contents
1228  * @data: The raw bytes of the packet.
1229  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1230  *                 a new authentication token will be placed at the
1231  *                 end of this list for this packet.
1232  * @new_auth_tok: Pointer to a pointer to memory that this function
1233  *                allocates; sets the memory address of the pointer to
1234  *                NULL on error. This object is added to the
1235  *                auth_tok_list.
1236  * @packet_size: This function writes the size of the parsed packet
1237  *               into this memory location; zero on error.
1238  * @max_packet_size: The maximum allowable packet size
1239  *
1240  * Returns zero on success; non-zero on error.
1241  */
1242 static int
1243 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1244                    unsigned char *data, struct list_head *auth_tok_list,
1245                    struct ecryptfs_auth_tok **new_auth_tok,
1246                    size_t *packet_size, size_t max_packet_size)
1247 {
1248         size_t body_size;
1249         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1250         size_t length_size;
1251         int rc = 0;
1252
1253         (*packet_size) = 0;
1254         (*new_auth_tok) = NULL;
1255         /**
1256          * This format is inspired by OpenPGP; see RFC 2440
1257          * packet tag 1
1258          *
1259          * Tag 1 identifier (1 byte)
1260          * Max Tag 1 packet size (max 3 bytes)
1261          * Version (1 byte)
1262          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1263          * Cipher identifier (1 byte)
1264          * Encrypted key size (arbitrary)
1265          *
1266          * 12 bytes minimum packet size
1267          */
1268         if (unlikely(max_packet_size < 12)) {
1269                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1270                 rc = -EINVAL;
1271                 goto out;
1272         }
1273         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1274                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1275                        ECRYPTFS_TAG_1_PACKET_TYPE);
1276                 rc = -EINVAL;
1277                 goto out;
1278         }
1279         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1280          * at end of function upon failure */
1281         auth_tok_list_item =
1282                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1283                                   GFP_KERNEL);
1284         if (!auth_tok_list_item) {
1285                 printk(KERN_ERR "Unable to allocate memory\n");
1286                 rc = -ENOMEM;
1287                 goto out;
1288         }
1289         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1290         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1291                                           &length_size);
1292         if (rc) {
1293                 printk(KERN_WARNING "Error parsing packet length; "
1294                        "rc = [%d]\n", rc);
1295                 goto out_free;
1296         }
1297         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1298                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1299                 rc = -EINVAL;
1300                 goto out_free;
1301         }
1302         (*packet_size) += length_size;
1303         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1304                 printk(KERN_WARNING "Packet size exceeds max\n");
1305                 rc = -EINVAL;
1306                 goto out_free;
1307         }
1308         if (unlikely(data[(*packet_size)++] != 0x03)) {
1309                 printk(KERN_WARNING "Unknown version number [%d]\n",
1310                        data[(*packet_size) - 1]);
1311                 rc = -EINVAL;
1312                 goto out_free;
1313         }
1314         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1315                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1316         *packet_size += ECRYPTFS_SIG_SIZE;
1317         /* This byte is skipped because the kernel does not need to
1318          * know which public key encryption algorithm was used */
1319         (*packet_size)++;
1320         (*new_auth_tok)->session_key.encrypted_key_size =
1321                 body_size - (ECRYPTFS_SIG_SIZE + 2);
1322         if ((*new_auth_tok)->session_key.encrypted_key_size
1323             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1324                 printk(KERN_WARNING "Tag 1 packet contains key larger "
1325                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1326                 rc = -EINVAL;
1327                 goto out;
1328         }
1329         memcpy((*new_auth_tok)->session_key.encrypted_key,
1330                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1331         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1332         (*new_auth_tok)->session_key.flags &=
1333                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1334         (*new_auth_tok)->session_key.flags |=
1335                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1336         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1337         (*new_auth_tok)->flags = 0;
1338         (*new_auth_tok)->session_key.flags &=
1339                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1340         (*new_auth_tok)->session_key.flags &=
1341                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1342         list_add(&auth_tok_list_item->list, auth_tok_list);
1343         goto out;
1344 out_free:
1345         (*new_auth_tok) = NULL;
1346         memset(auth_tok_list_item, 0,
1347                sizeof(struct ecryptfs_auth_tok_list_item));
1348         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1349                         auth_tok_list_item);
1350 out:
1351         if (rc)
1352                 (*packet_size) = 0;
1353         return rc;
1354 }
1355
1356 /**
1357  * parse_tag_3_packet
1358  * @crypt_stat: The cryptographic context to modify based on packet
1359  *              contents.
1360  * @data: The raw bytes of the packet.
1361  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1362  *                 a new authentication token will be placed at the end
1363  *                 of this list for this packet.
1364  * @new_auth_tok: Pointer to a pointer to memory that this function
1365  *                allocates; sets the memory address of the pointer to
1366  *                NULL on error. This object is added to the
1367  *                auth_tok_list.
1368  * @packet_size: This function writes the size of the parsed packet
1369  *               into this memory location; zero on error.
1370  * @max_packet_size: maximum number of bytes to parse
1371  *
1372  * Returns zero on success; non-zero on error.
1373  */
1374 static int
1375 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1376                    unsigned char *data, struct list_head *auth_tok_list,
1377                    struct ecryptfs_auth_tok **new_auth_tok,
1378                    size_t *packet_size, size_t max_packet_size)
1379 {
1380         size_t body_size;
1381         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1382         size_t length_size;
1383         int rc = 0;
1384
1385         (*packet_size) = 0;
1386         (*new_auth_tok) = NULL;
1387         /**
1388          *This format is inspired by OpenPGP; see RFC 2440
1389          * packet tag 3
1390          *
1391          * Tag 3 identifier (1 byte)
1392          * Max Tag 3 packet size (max 3 bytes)
1393          * Version (1 byte)
1394          * Cipher code (1 byte)
1395          * S2K specifier (1 byte)
1396          * Hash identifier (1 byte)
1397          * Salt (ECRYPTFS_SALT_SIZE)
1398          * Hash iterations (1 byte)
1399          * Encrypted key (arbitrary)
1400          *
1401          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1402          */
1403         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1404                 printk(KERN_ERR "Max packet size too large\n");
1405                 rc = -EINVAL;
1406                 goto out;
1407         }
1408         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1409                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1410                        ECRYPTFS_TAG_3_PACKET_TYPE);
1411                 rc = -EINVAL;
1412                 goto out;
1413         }
1414         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1415          * at end of function upon failure */
1416         auth_tok_list_item =
1417             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1418         if (!auth_tok_list_item) {
1419                 printk(KERN_ERR "Unable to allocate memory\n");
1420                 rc = -ENOMEM;
1421                 goto out;
1422         }
1423         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1424         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1425                                           &length_size);
1426         if (rc) {
1427                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1428                        rc);
1429                 goto out_free;
1430         }
1431         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1432                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1433                 rc = -EINVAL;
1434                 goto out_free;
1435         }
1436         (*packet_size) += length_size;
1437         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1438                 printk(KERN_ERR "Packet size exceeds max\n");
1439                 rc = -EINVAL;
1440                 goto out_free;
1441         }
1442         (*new_auth_tok)->session_key.encrypted_key_size =
1443                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1444         if ((*new_auth_tok)->session_key.encrypted_key_size
1445             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1446                 printk(KERN_WARNING "Tag 3 packet contains key larger "
1447                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1448                 rc = -EINVAL;
1449                 goto out_free;
1450         }
1451         if (unlikely(data[(*packet_size)++] != 0x04)) {
1452                 printk(KERN_WARNING "Unknown version number [%d]\n",
1453                        data[(*packet_size) - 1]);
1454                 rc = -EINVAL;
1455                 goto out_free;
1456         }
1457         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1458                                             (u16)data[(*packet_size)]);
1459         if (rc)
1460                 goto out_free;
1461         /* A little extra work to differentiate among the AES key
1462          * sizes; see RFC2440 */
1463         switch(data[(*packet_size)++]) {
1464         case RFC2440_CIPHER_AES_192:
1465                 crypt_stat->key_size = 24;
1466                 break;
1467         default:
1468                 crypt_stat->key_size =
1469                         (*new_auth_tok)->session_key.encrypted_key_size;
1470         }
1471         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1472         if (rc)
1473                 goto out_free;
1474         if (unlikely(data[(*packet_size)++] != 0x03)) {
1475                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1476                 rc = -ENOSYS;
1477                 goto out_free;
1478         }
1479         /* TODO: finish the hash mapping */
1480         switch (data[(*packet_size)++]) {
1481         case 0x01: /* See RFC2440 for these numbers and their mappings */
1482                 /* Choose MD5 */
1483                 memcpy((*new_auth_tok)->token.password.salt,
1484                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1485                 (*packet_size) += ECRYPTFS_SALT_SIZE;
1486                 /* This conversion was taken straight from RFC2440 */
1487                 (*new_auth_tok)->token.password.hash_iterations =
1488                         ((u32) 16 + (data[(*packet_size)] & 15))
1489                                 << ((data[(*packet_size)] >> 4) + 6);
1490                 (*packet_size)++;
1491                 /* Friendly reminder:
1492                  * (*new_auth_tok)->session_key.encrypted_key_size =
1493                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1494                 memcpy((*new_auth_tok)->session_key.encrypted_key,
1495                        &data[(*packet_size)],
1496                        (*new_auth_tok)->session_key.encrypted_key_size);
1497                 (*packet_size) +=
1498                         (*new_auth_tok)->session_key.encrypted_key_size;
1499                 (*new_auth_tok)->session_key.flags &=
1500                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1501                 (*new_auth_tok)->session_key.flags |=
1502                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1503                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1504                 break;
1505         default:
1506                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1507                                 "[%d]\n", data[(*packet_size) - 1]);
1508                 rc = -ENOSYS;
1509                 goto out_free;
1510         }
1511         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1512         /* TODO: Parametarize; we might actually want userspace to
1513          * decrypt the session key. */
1514         (*new_auth_tok)->session_key.flags &=
1515                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1516         (*new_auth_tok)->session_key.flags &=
1517                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1518         list_add(&auth_tok_list_item->list, auth_tok_list);
1519         goto out;
1520 out_free:
1521         (*new_auth_tok) = NULL;
1522         memset(auth_tok_list_item, 0,
1523                sizeof(struct ecryptfs_auth_tok_list_item));
1524         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1525                         auth_tok_list_item);
1526 out:
1527         if (rc)
1528                 (*packet_size) = 0;
1529         return rc;
1530 }
1531
1532 /**
1533  * parse_tag_11_packet
1534  * @data: The raw bytes of the packet
1535  * @contents: This function writes the data contents of the literal
1536  *            packet into this memory location
1537  * @max_contents_bytes: The maximum number of bytes that this function
1538  *                      is allowed to write into contents
1539  * @tag_11_contents_size: This function writes the size of the parsed
1540  *                        contents into this memory location; zero on
1541  *                        error
1542  * @packet_size: This function writes the size of the parsed packet
1543  *               into this memory location; zero on error
1544  * @max_packet_size: maximum number of bytes to parse
1545  *
1546  * Returns zero on success; non-zero on error.
1547  */
1548 static int
1549 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1550                     size_t max_contents_bytes, size_t *tag_11_contents_size,
1551                     size_t *packet_size, size_t max_packet_size)
1552 {
1553         size_t body_size;
1554         size_t length_size;
1555         int rc = 0;
1556
1557         (*packet_size) = 0;
1558         (*tag_11_contents_size) = 0;
1559         /* This format is inspired by OpenPGP; see RFC 2440
1560          * packet tag 11
1561          *
1562          * Tag 11 identifier (1 byte)
1563          * Max Tag 11 packet size (max 3 bytes)
1564          * Binary format specifier (1 byte)
1565          * Filename length (1 byte)
1566          * Filename ("_CONSOLE") (8 bytes)
1567          * Modification date (4 bytes)
1568          * Literal data (arbitrary)
1569          *
1570          * We need at least 16 bytes of data for the packet to even be
1571          * valid.
1572          */
1573         if (max_packet_size < 16) {
1574                 printk(KERN_ERR "Maximum packet size too small\n");
1575                 rc = -EINVAL;
1576                 goto out;
1577         }
1578         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1579                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1580                 rc = -EINVAL;
1581                 goto out;
1582         }
1583         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1584                                           &length_size);
1585         if (rc) {
1586                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1587                 goto out;
1588         }
1589         if (body_size < 14) {
1590                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1591                 rc = -EINVAL;
1592                 goto out;
1593         }
1594         (*packet_size) += length_size;
1595         (*tag_11_contents_size) = (body_size - 14);
1596         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1597                 printk(KERN_ERR "Packet size exceeds max\n");
1598                 rc = -EINVAL;
1599                 goto out;
1600         }
1601         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1602                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1603                        "expected size\n");
1604                 rc = -EINVAL;
1605                 goto out;
1606         }
1607         if (data[(*packet_size)++] != 0x62) {
1608                 printk(KERN_WARNING "Unrecognizable packet\n");
1609                 rc = -EINVAL;
1610                 goto out;
1611         }
1612         if (data[(*packet_size)++] != 0x08) {
1613                 printk(KERN_WARNING "Unrecognizable packet\n");
1614                 rc = -EINVAL;
1615                 goto out;
1616         }
1617         (*packet_size) += 12; /* Ignore filename and modification date */
1618         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1619         (*packet_size) += (*tag_11_contents_size);
1620 out:
1621         if (rc) {
1622                 (*packet_size) = 0;
1623                 (*tag_11_contents_size) = 0;
1624         }
1625         return rc;
1626 }
1627
1628 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1629                                       struct ecryptfs_auth_tok **auth_tok,
1630                                       char *sig)
1631 {
1632         int rc = 0;
1633
1634         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1635         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1636                 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1637                 if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1638                         printk(KERN_ERR "Could not find key with description: [%s]\n",
1639                               sig);
1640                         rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1641                         (*auth_tok_key) = NULL;
1642                         goto out;
1643                 }
1644         }
1645         down_write(&(*auth_tok_key)->sem);
1646         rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1647         if (rc) {
1648                 up_write(&(*auth_tok_key)->sem);
1649                 key_put(*auth_tok_key);
1650                 (*auth_tok_key) = NULL;
1651                 goto out;
1652         }
1653 out:
1654         return rc;
1655 }
1656
1657 /**
1658  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1659  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1660  * @crypt_stat: The cryptographic context
1661  *
1662  * Returns zero on success; non-zero error otherwise
1663  */
1664 static int
1665 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1666                                          struct ecryptfs_crypt_stat *crypt_stat)
1667 {
1668         struct scatterlist dst_sg[2];
1669         struct scatterlist src_sg[2];
1670         struct mutex *tfm_mutex;
1671         struct blkcipher_desc desc = {
1672                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1673         };
1674         int rc = 0;
1675
1676         if (unlikely(ecryptfs_verbosity > 0)) {
1677                 ecryptfs_printk(
1678                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1679                         auth_tok->token.password.session_key_encryption_key_bytes);
1680                 ecryptfs_dump_hex(
1681                         auth_tok->token.password.session_key_encryption_key,
1682                         auth_tok->token.password.session_key_encryption_key_bytes);
1683         }
1684         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1685                                                         crypt_stat->cipher);
1686         if (unlikely(rc)) {
1687                 printk(KERN_ERR "Internal error whilst attempting to get "
1688                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1689                        crypt_stat->cipher, rc);
1690                 goto out;
1691         }
1692         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1693                                  auth_tok->session_key.encrypted_key_size,
1694                                  src_sg, 2);
1695         if (rc < 1 || rc > 2) {
1696                 printk(KERN_ERR "Internal error whilst attempting to convert "
1697                         "auth_tok->session_key.encrypted_key to scatterlist; "
1698                         "expected rc = 1; got rc = [%d]. "
1699                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1700                         auth_tok->session_key.encrypted_key_size);
1701                 goto out;
1702         }
1703         auth_tok->session_key.decrypted_key_size =
1704                 auth_tok->session_key.encrypted_key_size;
1705         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1706                                  auth_tok->session_key.decrypted_key_size,
1707                                  dst_sg, 2);
1708         if (rc < 1 || rc > 2) {
1709                 printk(KERN_ERR "Internal error whilst attempting to convert "
1710                         "auth_tok->session_key.decrypted_key to scatterlist; "
1711                         "expected rc = 1; got rc = [%d]\n", rc);
1712                 goto out;
1713         }
1714         mutex_lock(tfm_mutex);
1715         rc = crypto_blkcipher_setkey(
1716                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1717                 crypt_stat->key_size);
1718         if (unlikely(rc < 0)) {
1719                 mutex_unlock(tfm_mutex);
1720                 printk(KERN_ERR "Error setting key for crypto context\n");
1721                 rc = -EINVAL;
1722                 goto out;
1723         }
1724         rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1725                                       auth_tok->session_key.encrypted_key_size);
1726         mutex_unlock(tfm_mutex);
1727         if (unlikely(rc)) {
1728                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1729                 goto out;
1730         }
1731         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1732         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1733                auth_tok->session_key.decrypted_key_size);
1734         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1735         if (unlikely(ecryptfs_verbosity > 0)) {
1736                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1737                                 crypt_stat->key_size);
1738                 ecryptfs_dump_hex(crypt_stat->key,
1739                                   crypt_stat->key_size);
1740         }
1741 out:
1742         return rc;
1743 }
1744
1745 /**
1746  * ecryptfs_parse_packet_set
1747  * @crypt_stat: The cryptographic context
1748  * @src: Virtual address of region of memory containing the packets
1749  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1750  *
1751  * Get crypt_stat to have the file's session key if the requisite key
1752  * is available to decrypt the session key.
1753  *
1754  * Returns Zero if a valid authentication token was retrieved and
1755  * processed; negative value for file not encrypted or for error
1756  * conditions.
1757  */
1758 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1759                               unsigned char *src,
1760                               struct dentry *ecryptfs_dentry)
1761 {
1762         size_t i = 0;
1763         size_t found_auth_tok;
1764         size_t next_packet_is_auth_tok_packet;
1765         struct list_head auth_tok_list;
1766         struct ecryptfs_auth_tok *matching_auth_tok;
1767         struct ecryptfs_auth_tok *candidate_auth_tok;
1768         char *candidate_auth_tok_sig;
1769         size_t packet_size;
1770         struct ecryptfs_auth_tok *new_auth_tok;
1771         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1772         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1773         size_t tag_11_contents_size;
1774         size_t tag_11_packet_size;
1775         struct key *auth_tok_key = NULL;
1776         int rc = 0;
1777
1778         INIT_LIST_HEAD(&auth_tok_list);
1779         /* Parse the header to find as many packets as we can; these will be
1780          * added the our &auth_tok_list */
1781         next_packet_is_auth_tok_packet = 1;
1782         while (next_packet_is_auth_tok_packet) {
1783                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1784
1785                 switch (src[i]) {
1786                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1787                         rc = parse_tag_3_packet(crypt_stat,
1788                                                 (unsigned char *)&src[i],
1789                                                 &auth_tok_list, &new_auth_tok,
1790                                                 &packet_size, max_packet_size);
1791                         if (rc) {
1792                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1793                                                 "tag 3 packet\n");
1794                                 rc = -EIO;
1795                                 goto out_wipe_list;
1796                         }
1797                         i += packet_size;
1798                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1799                                                  sig_tmp_space,
1800                                                  ECRYPTFS_SIG_SIZE,
1801                                                  &tag_11_contents_size,
1802                                                  &tag_11_packet_size,
1803                                                  max_packet_size);
1804                         if (rc) {
1805                                 ecryptfs_printk(KERN_ERR, "No valid "
1806                                                 "(ecryptfs-specific) literal "
1807                                                 "packet containing "
1808                                                 "authentication token "
1809                                                 "signature found after "
1810                                                 "tag 3 packet\n");
1811                                 rc = -EIO;
1812                                 goto out_wipe_list;
1813                         }
1814                         i += tag_11_packet_size;
1815                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1816                                 ecryptfs_printk(KERN_ERR, "Expected "
1817                                                 "signature of size [%d]; "
1818                                                 "read size [%zd]\n",
1819                                                 ECRYPTFS_SIG_SIZE,
1820                                                 tag_11_contents_size);
1821                                 rc = -EIO;
1822                                 goto out_wipe_list;
1823                         }
1824                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1825                                         sig_tmp_space, tag_11_contents_size);
1826                         new_auth_tok->token.password.signature[
1827                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1828                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1829                         break;
1830                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1831                         rc = parse_tag_1_packet(crypt_stat,
1832                                                 (unsigned char *)&src[i],
1833                                                 &auth_tok_list, &new_auth_tok,
1834                                                 &packet_size, max_packet_size);
1835                         if (rc) {
1836                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1837                                                 "tag 1 packet\n");
1838                                 rc = -EIO;
1839                                 goto out_wipe_list;
1840                         }
1841                         i += packet_size;
1842                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1843                         break;
1844                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1845                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1846                                         "(Tag 11 not allowed by itself)\n");
1847                         rc = -EIO;
1848                         goto out_wipe_list;
1849                         break;
1850                 default:
1851                         ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1852                                         "of the file header; hex value of "
1853                                         "character is [0x%.2x]\n", i, src[i]);
1854                         next_packet_is_auth_tok_packet = 0;
1855                 }
1856         }
1857         if (list_empty(&auth_tok_list)) {
1858                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1859                        "eCryptfs file; this is not supported in this version "
1860                        "of the eCryptfs kernel module\n");
1861                 rc = -EINVAL;
1862                 goto out;
1863         }
1864         /* auth_tok_list contains the set of authentication tokens
1865          * parsed from the metadata. We need to find a matching
1866          * authentication token that has the secret component(s)
1867          * necessary to decrypt the EFEK in the auth_tok parsed from
1868          * the metadata. There may be several potential matches, but
1869          * just one will be sufficient to decrypt to get the FEK. */
1870 find_next_matching_auth_tok:
1871         found_auth_tok = 0;
1872         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1873                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1874                 if (unlikely(ecryptfs_verbosity > 0)) {
1875                         ecryptfs_printk(KERN_DEBUG,
1876                                         "Considering cadidate auth tok:\n");
1877                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1878                 }
1879                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1880                                                candidate_auth_tok);
1881                 if (rc) {
1882                         printk(KERN_ERR
1883                                "Unrecognized candidate auth tok type: [%d]\n",
1884                                candidate_auth_tok->token_type);
1885                         rc = -EINVAL;
1886                         goto out_wipe_list;
1887                 }
1888                 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1889                                                &matching_auth_tok,
1890                                                crypt_stat->mount_crypt_stat,
1891                                                candidate_auth_tok_sig);
1892                 if (!rc) {
1893                         found_auth_tok = 1;
1894                         goto found_matching_auth_tok;
1895                 }
1896         }
1897         if (!found_auth_tok) {
1898                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1899                                 "authentication token\n");
1900                 rc = -EIO;
1901                 goto out_wipe_list;
1902         }
1903 found_matching_auth_tok:
1904         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1905                 memcpy(&(candidate_auth_tok->token.private_key),
1906                        &(matching_auth_tok->token.private_key),
1907                        sizeof(struct ecryptfs_private_key));
1908                 up_write(&(auth_tok_key->sem));
1909                 key_put(auth_tok_key);
1910                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1911                                                        crypt_stat);
1912         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1913                 memcpy(&(candidate_auth_tok->token.password),
1914                        &(matching_auth_tok->token.password),
1915                        sizeof(struct ecryptfs_password));
1916                 up_write(&(auth_tok_key->sem));
1917                 key_put(auth_tok_key);
1918                 rc = decrypt_passphrase_encrypted_session_key(
1919                         candidate_auth_tok, crypt_stat);
1920         } else {
1921                 up_write(&(auth_tok_key->sem));
1922                 key_put(auth_tok_key);
1923                 rc = -EINVAL;
1924         }
1925         if (rc) {
1926                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1927
1928                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1929                                 "session key for authentication token with sig "
1930                                 "[%.*s]; rc = [%d]. Removing auth tok "
1931                                 "candidate from the list and searching for "
1932                                 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1933                                 candidate_auth_tok_sig, rc);
1934                 list_for_each_entry_safe(auth_tok_list_item,
1935                                          auth_tok_list_item_tmp,
1936                                          &auth_tok_list, list) {
1937                         if (candidate_auth_tok
1938                             == &auth_tok_list_item->auth_tok) {
1939                                 list_del(&auth_tok_list_item->list);
1940                                 kmem_cache_free(
1941                                         ecryptfs_auth_tok_list_item_cache,
1942                                         auth_tok_list_item);
1943                                 goto find_next_matching_auth_tok;
1944                         }
1945                 }
1946                 BUG();
1947         }
1948         rc = ecryptfs_compute_root_iv(crypt_stat);
1949         if (rc) {
1950                 ecryptfs_printk(KERN_ERR, "Error computing "
1951                                 "the root IV\n");
1952                 goto out_wipe_list;
1953         }
1954         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1955         if (rc) {
1956                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1957                                 "context for cipher [%s]; rc = [%d]\n",
1958                                 crypt_stat->cipher, rc);
1959         }
1960 out_wipe_list:
1961         wipe_auth_tok_list(&auth_tok_list);
1962 out:
1963         return rc;
1964 }
1965
1966 static int
1967 pki_encrypt_session_key(struct key *auth_tok_key,
1968                         struct ecryptfs_auth_tok *auth_tok,
1969                         struct ecryptfs_crypt_stat *crypt_stat,
1970                         struct ecryptfs_key_record *key_rec)
1971 {
1972         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1973         char *payload = NULL;
1974         size_t payload_len = 0;
1975         struct ecryptfs_message *msg;
1976         int rc;
1977
1978         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1979                                  ecryptfs_code_for_cipher_string(
1980                                          crypt_stat->cipher,
1981                                          crypt_stat->key_size),
1982                                  crypt_stat, &payload, &payload_len);
1983         up_write(&(auth_tok_key->sem));
1984         key_put(auth_tok_key);
1985         if (rc) {
1986                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1987                 goto out;
1988         }
1989         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1990         if (rc) {
1991                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1992                                 "ecryptfsd\n");
1993                 goto out;
1994         }
1995         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1996         if (rc) {
1997                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1998                                 "from the user space daemon\n");
1999                 rc = -EIO;
2000                 goto out;
2001         }
2002         rc = parse_tag_67_packet(key_rec, msg);
2003         if (rc)
2004                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2005         kfree(msg);
2006 out:
2007         kfree(payload);
2008         return rc;
2009 }
2010 /**
2011  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2012  * @dest: Buffer into which to write the packet
2013  * @remaining_bytes: Maximum number of bytes that can be writtn
2014  * @auth_tok_key: The authentication token key to unlock and put when done with
2015  *                @auth_tok
2016  * @auth_tok: The authentication token used for generating the tag 1 packet
2017  * @crypt_stat: The cryptographic context
2018  * @key_rec: The key record struct for the tag 1 packet
2019  * @packet_size: This function will write the number of bytes that end
2020  *               up constituting the packet; set to zero on error
2021  *
2022  * Returns zero on success; non-zero on error.
2023  */
2024 static int
2025 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2026                    struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2027                    struct ecryptfs_crypt_stat *crypt_stat,
2028                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2029 {
2030         size_t i;
2031         size_t encrypted_session_key_valid = 0;
2032         size_t packet_size_length;
2033         size_t max_packet_size;
2034         int rc = 0;
2035
2036         (*packet_size) = 0;
2037         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2038                           ECRYPTFS_SIG_SIZE);
2039         encrypted_session_key_valid = 0;
2040         for (i = 0; i < crypt_stat->key_size; i++)
2041                 encrypted_session_key_valid |=
2042                         auth_tok->session_key.encrypted_key[i];
2043         if (encrypted_session_key_valid) {
2044                 memcpy(key_rec->enc_key,
2045                        auth_tok->session_key.encrypted_key,
2046                        auth_tok->session_key.encrypted_key_size);
2047                 up_write(&(auth_tok_key->sem));
2048                 key_put(auth_tok_key);
2049                 goto encrypted_session_key_set;
2050         }
2051         if (auth_tok->session_key.encrypted_key_size == 0)
2052                 auth_tok->session_key.encrypted_key_size =
2053                         auth_tok->token.private_key.key_size;
2054         rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2055                                      key_rec);
2056         if (rc) {
2057                 printk(KERN_ERR "Failed to encrypt session key via a key "
2058                        "module; rc = [%d]\n", rc);
2059                 goto out;
2060         }
2061         if (ecryptfs_verbosity > 0) {
2062                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2063                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2064         }
2065 encrypted_session_key_set:
2066         /* This format is inspired by OpenPGP; see RFC 2440
2067          * packet tag 1 */
2068         max_packet_size = (1                         /* Tag 1 identifier */
2069                            + 3                       /* Max Tag 1 packet size */
2070                            + 1                       /* Version */
2071                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
2072                            + 1                       /* Cipher identifier */
2073                            + key_rec->enc_key_size); /* Encrypted key size */
2074         if (max_packet_size > (*remaining_bytes)) {
2075                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2076                        "need up to [%td] bytes, but there are only [%td] "
2077                        "available\n", max_packet_size, (*remaining_bytes));
2078                 rc = -EINVAL;
2079                 goto out;
2080         }
2081         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2082         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2083                                           (max_packet_size - 4),
2084                                           &packet_size_length);
2085         if (rc) {
2086                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2087                                 "header; cannot generate packet length\n");
2088                 goto out;
2089         }
2090         (*packet_size) += packet_size_length;
2091         dest[(*packet_size)++] = 0x03; /* version 3 */
2092         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2093         (*packet_size) += ECRYPTFS_SIG_SIZE;
2094         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2095         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2096                key_rec->enc_key_size);
2097         (*packet_size) += key_rec->enc_key_size;
2098 out:
2099         if (rc)
2100                 (*packet_size) = 0;
2101         else
2102                 (*remaining_bytes) -= (*packet_size);
2103         return rc;
2104 }
2105
2106 /**
2107  * write_tag_11_packet
2108  * @dest: Target into which Tag 11 packet is to be written
2109  * @remaining_bytes: Maximum packet length
2110  * @contents: Byte array of contents to copy in
2111  * @contents_length: Number of bytes in contents
2112  * @packet_length: Length of the Tag 11 packet written; zero on error
2113  *
2114  * Returns zero on success; non-zero on error.
2115  */
2116 static int
2117 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2118                     size_t contents_length, size_t *packet_length)
2119 {
2120         size_t packet_size_length;
2121         size_t max_packet_size;
2122         int rc = 0;
2123
2124         (*packet_length) = 0;
2125         /* This format is inspired by OpenPGP; see RFC 2440
2126          * packet tag 11 */
2127         max_packet_size = (1                   /* Tag 11 identifier */
2128                            + 3                 /* Max Tag 11 packet size */
2129                            + 1                 /* Binary format specifier */
2130                            + 1                 /* Filename length */
2131                            + 8                 /* Filename ("_CONSOLE") */
2132                            + 4                 /* Modification date */
2133                            + contents_length); /* Literal data */
2134         if (max_packet_size > (*remaining_bytes)) {
2135                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2136                        "need up to [%td] bytes, but there are only [%td] "
2137                        "available\n", max_packet_size, (*remaining_bytes));
2138                 rc = -EINVAL;
2139                 goto out;
2140         }
2141         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2142         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2143                                           (max_packet_size - 4),
2144                                           &packet_size_length);
2145         if (rc) {
2146                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2147                        "generate packet length. rc = [%d]\n", rc);
2148                 goto out;
2149         }
2150         (*packet_length) += packet_size_length;
2151         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2152         dest[(*packet_length)++] = 8;
2153         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2154         (*packet_length) += 8;
2155         memset(&dest[(*packet_length)], 0x00, 4);
2156         (*packet_length) += 4;
2157         memcpy(&dest[(*packet_length)], contents, contents_length);
2158         (*packet_length) += contents_length;
2159  out:
2160         if (rc)
2161                 (*packet_length) = 0;
2162         else
2163                 (*remaining_bytes) -= (*packet_length);
2164         return rc;
2165 }
2166
2167 /**
2168  * write_tag_3_packet
2169  * @dest: Buffer into which to write the packet
2170  * @remaining_bytes: Maximum number of bytes that can be written
2171  * @auth_tok: Authentication token
2172  * @crypt_stat: The cryptographic context
2173  * @key_rec: encrypted key
2174  * @packet_size: This function will write the number of bytes that end
2175  *               up constituting the packet; set to zero on error
2176  *
2177  * Returns zero on success; non-zero on error.
2178  */
2179 static int
2180 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2181                    struct ecryptfs_auth_tok *auth_tok,
2182                    struct ecryptfs_crypt_stat *crypt_stat,
2183                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2184 {
2185         size_t i;
2186         size_t encrypted_session_key_valid = 0;
2187         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2188         struct scatterlist dst_sg[2];
2189         struct scatterlist src_sg[2];
2190         struct mutex *tfm_mutex = NULL;
2191         u8 cipher_code;
2192         size_t packet_size_length;
2193         size_t max_packet_size;
2194         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2195                 crypt_stat->mount_crypt_stat;
2196         struct blkcipher_desc desc = {
2197                 .tfm = NULL,
2198                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2199         };
2200         int rc = 0;
2201
2202         (*packet_size) = 0;
2203         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2204                           ECRYPTFS_SIG_SIZE);
2205         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2206                                                         crypt_stat->cipher);
2207         if (unlikely(rc)) {
2208                 printk(KERN_ERR "Internal error whilst attempting to get "
2209                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2210                        crypt_stat->cipher, rc);
2211                 goto out;
2212         }
2213         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2214                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2215
2216                 printk(KERN_WARNING "No key size specified at mount; "
2217                        "defaulting to [%d]\n", alg->max_keysize);
2218                 mount_crypt_stat->global_default_cipher_key_size =
2219                         alg->max_keysize;
2220         }
2221         if (crypt_stat->key_size == 0)
2222                 crypt_stat->key_size =
2223                         mount_crypt_stat->global_default_cipher_key_size;
2224         if (auth_tok->session_key.encrypted_key_size == 0)
2225                 auth_tok->session_key.encrypted_key_size =
2226                         crypt_stat->key_size;
2227         if (crypt_stat->key_size == 24
2228             && strcmp("aes", crypt_stat->cipher) == 0) {
2229                 memset((crypt_stat->key + 24), 0, 8);
2230                 auth_tok->session_key.encrypted_key_size = 32;
2231         } else
2232                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2233         key_rec->enc_key_size =
2234                 auth_tok->session_key.encrypted_key_size;
2235         encrypted_session_key_valid = 0;
2236         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2237                 encrypted_session_key_valid |=
2238                         auth_tok->session_key.encrypted_key[i];
2239         if (encrypted_session_key_valid) {
2240                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2241                                 "using auth_tok->session_key.encrypted_key, "
2242                                 "where key_rec->enc_key_size = [%zd]\n",
2243                                 key_rec->enc_key_size);
2244                 memcpy(key_rec->enc_key,
2245                        auth_tok->session_key.encrypted_key,
2246                        key_rec->enc_key_size);
2247                 goto encrypted_session_key_set;
2248         }
2249         if (auth_tok->token.password.flags &
2250             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2251                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2252                                 "session key encryption key of size [%d]\n",
2253                                 auth_tok->token.password.
2254                                 session_key_encryption_key_bytes);
2255                 memcpy(session_key_encryption_key,
2256                        auth_tok->token.password.session_key_encryption_key,
2257                        crypt_stat->key_size);
2258                 ecryptfs_printk(KERN_DEBUG,
2259                                 "Cached session key encryption key:\n");
2260                 if (ecryptfs_verbosity > 0)
2261                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2262         }
2263         if (unlikely(ecryptfs_verbosity > 0)) {
2264                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2265                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2266         }
2267         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2268                                  src_sg, 2);
2269         if (rc < 1 || rc > 2) {
2270                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2271                                 "for crypt_stat session key; expected rc = 1; "
2272                                 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2273                                 rc, key_rec->enc_key_size);
2274                 rc = -ENOMEM;
2275                 goto out;
2276         }
2277         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2278                                  dst_sg, 2);
2279         if (rc < 1 || rc > 2) {
2280                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2281                                 "for crypt_stat encrypted session key; "
2282                                 "expected rc = 1; got rc = [%d]. "
2283                                 "key_rec->enc_key_size = [%zd]\n", rc,
2284                                 key_rec->enc_key_size);
2285                 rc = -ENOMEM;
2286                 goto out;
2287         }
2288         mutex_lock(tfm_mutex);
2289         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2290                                      crypt_stat->key_size);
2291         if (rc < 0) {
2292                 mutex_unlock(tfm_mutex);
2293                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2294                                 "context; rc = [%d]\n", rc);
2295                 goto out;
2296         }
2297         rc = 0;
2298         ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2299                         crypt_stat->key_size);
2300         rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2301                                       (*key_rec).enc_key_size);
2302         mutex_unlock(tfm_mutex);
2303         if (rc) {
2304                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2305                 goto out;
2306         }
2307         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2308         if (ecryptfs_verbosity > 0) {
2309                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2310                                 key_rec->enc_key_size);
2311                 ecryptfs_dump_hex(key_rec->enc_key,
2312                                   key_rec->enc_key_size);
2313         }
2314 encrypted_session_key_set:
2315         /* This format is inspired by OpenPGP; see RFC 2440
2316          * packet tag 3 */
2317         max_packet_size = (1                         /* Tag 3 identifier */
2318                            + 3                       /* Max Tag 3 packet size */
2319                            + 1                       /* Version */
2320                            + 1                       /* Cipher code */
2321                            + 1                       /* S2K specifier */
2322                            + 1                       /* Hash identifier */
2323                            + ECRYPTFS_SALT_SIZE      /* Salt */
2324                            + 1                       /* Hash iterations */
2325                            + key_rec->enc_key_size); /* Encrypted key size */
2326         if (max_packet_size > (*remaining_bytes)) {
2327                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2328                        "there are only [%td] available\n", max_packet_size,
2329                        (*remaining_bytes));
2330                 rc = -EINVAL;
2331                 goto out;
2332         }
2333         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2334         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2335          * to get the number of octets in the actual Tag 3 packet */
2336         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2337                                           (max_packet_size - 4),
2338                                           &packet_size_length);
2339         if (rc) {
2340                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2341                        "generate packet length. rc = [%d]\n", rc);
2342                 goto out;
2343         }
2344         (*packet_size) += packet_size_length;
2345         dest[(*packet_size)++] = 0x04; /* version 4 */
2346         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2347          * specified with strings */
2348         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2349                                                       crypt_stat->key_size);
2350         if (cipher_code == 0) {
2351                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2352                                 "cipher [%s]\n", crypt_stat->cipher);
2353                 rc = -EINVAL;
2354                 goto out;
2355         }
2356         dest[(*packet_size)++] = cipher_code;
2357         dest[(*packet_size)++] = 0x03;  /* S2K */
2358         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2359         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2360                ECRYPTFS_SALT_SIZE);
2361         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2362         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2363         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2364                key_rec->enc_key_size);
2365         (*packet_size) += key_rec->enc_key_size;
2366 out:
2367         if (rc)
2368                 (*packet_size) = 0;
2369         else
2370                 (*remaining_bytes) -= (*packet_size);
2371         return rc;
2372 }
2373
2374 struct kmem_cache *ecryptfs_key_record_cache;
2375
2376 /**
2377  * ecryptfs_generate_key_packet_set
2378  * @dest_base: Virtual address from which to write the key record set
2379  * @crypt_stat: The cryptographic context from which the
2380  *              authentication tokens will be retrieved
2381  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2382  *                   for the global parameters
2383  * @len: The amount written
2384  * @max: The maximum amount of data allowed to be written
2385  *
2386  * Generates a key packet set and writes it to the virtual address
2387  * passed in.
2388  *
2389  * Returns zero on success; non-zero on error.
2390  */
2391 int
2392 ecryptfs_generate_key_packet_set(char *dest_base,
2393                                  struct ecryptfs_crypt_stat *crypt_stat,
2394                                  struct dentry *ecryptfs_dentry, size_t *len,
2395                                  size_t max)
2396 {
2397         struct ecryptfs_auth_tok *auth_tok;
2398         struct key *auth_tok_key = NULL;
2399         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2400                 &ecryptfs_superblock_to_private(
2401                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2402         size_t written;
2403         struct ecryptfs_key_record *key_rec;
2404         struct ecryptfs_key_sig *key_sig;
2405         int rc = 0;
2406
2407         (*len) = 0;
2408         mutex_lock(&crypt_stat->keysig_list_mutex);
2409         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2410         if (!key_rec) {
2411                 rc = -ENOMEM;
2412                 goto out;
2413         }
2414         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2415                             crypt_stat_list) {
2416                 memset(key_rec, 0, sizeof(*key_rec));
2417                 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2418                                                            &auth_tok,
2419                                                            mount_crypt_stat,
2420                                                            key_sig->keysig);
2421                 if (rc) {
2422                         printk(KERN_WARNING "Unable to retrieve auth tok with "
2423                                "sig = [%s]\n", key_sig->keysig);
2424                         rc = process_find_global_auth_tok_for_sig_err(rc);
2425                         goto out_free;
2426                 }
2427                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2428                         rc = write_tag_3_packet((dest_base + (*len)),
2429                                                 &max, auth_tok,
2430                                                 crypt_stat, key_rec,
2431                                                 &written);
2432                         up_write(&(auth_tok_key->sem));
2433                         key_put(auth_tok_key);
2434                         if (rc) {
2435                                 ecryptfs_printk(KERN_WARNING, "Error "
2436                                                 "writing tag 3 packet\n");
2437                                 goto out_free;
2438                         }
2439                         (*len) += written;
2440                         /* Write auth tok signature packet */
2441                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2442                                                  key_rec->sig,
2443                                                  ECRYPTFS_SIG_SIZE, &written);
2444                         if (rc) {
2445                                 ecryptfs_printk(KERN_ERR, "Error writing "
2446                                                 "auth tok signature packet\n");
2447                                 goto out_free;
2448                         }
2449                         (*len) += written;
2450                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2451                         rc = write_tag_1_packet(dest_base + (*len), &max,
2452                                                 auth_tok_key, auth_tok,
2453                                                 crypt_stat, key_rec, &written);
2454                         if (rc) {
2455                                 ecryptfs_printk(KERN_WARNING, "Error "
2456                                                 "writing tag 1 packet\n");
2457                                 goto out_free;
2458                         }
2459                         (*len) += written;
2460                 } else {
2461                         up_write(&(auth_tok_key->sem));
2462                         key_put(auth_tok_key);
2463                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2464                                         "authentication token type\n");
2465                         rc = -EINVAL;
2466                         goto out_free;
2467                 }
2468         }
2469         if (likely(max > 0)) {
2470                 dest_base[(*len)] = 0x00;
2471         } else {
2472                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2473                 rc = -EIO;
2474         }
2475 out_free:
2476         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2477 out:
2478         if (rc)
2479                 (*len) = 0;
2480         mutex_unlock(&crypt_stat->keysig_list_mutex);
2481         return rc;
2482 }
2483
2484 struct kmem_cache *ecryptfs_key_sig_cache;
2485
2486 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2487 {
2488         struct ecryptfs_key_sig *new_key_sig;
2489
2490         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2491         if (!new_key_sig) {
2492                 printk(KERN_ERR
2493                        "Error allocating from ecryptfs_key_sig_cache\n");
2494                 return -ENOMEM;
2495         }
2496         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2497         new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2498         /* Caller must hold keysig_list_mutex */
2499         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2500
2501         return 0;
2502 }
2503
2504 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2505
2506 int
2507 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2508                              char *sig, u32 global_auth_tok_flags)
2509 {
2510         struct ecryptfs_global_auth_tok *new_auth_tok;
2511         int rc = 0;
2512
2513         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2514                                         GFP_KERNEL);
2515         if (!new_auth_tok) {
2516                 rc = -ENOMEM;
2517                 printk(KERN_ERR "Error allocating from "
2518                        "ecryptfs_global_auth_tok_cache\n");
2519                 goto out;
2520         }
2521         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2522         new_auth_tok->flags = global_auth_tok_flags;
2523         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2524         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2525         list_add(&new_auth_tok->mount_crypt_stat_list,
2526                  &mount_crypt_stat->global_auth_tok_list);
2527         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2528 out:
2529         return rc;
2530 }
2531