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