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         BUG_ON(s->auth_tok->token_type != ECRYPTFS_PASSWORD);
 616         sg_init_one(
 617                 &s->hash_sg,
 618                 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
 619                 s->auth_tok->token.password.session_key_encryption_key_bytes);
 620         s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 621         s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
 622                                              CRYPTO_ALG_ASYNC);
 623         if (IS_ERR(s->hash_desc.tfm)) {
 624                         rc = PTR_ERR(s->hash_desc.tfm);
 625                         printk(KERN_ERR "%s: Error attempting to "
 626                                "allocate hash crypto context; rc = [%d]\n",
 627                                __func__, rc);
 628                         goto out_free_unlock;
 629         }
 630         rc = crypto_hash_init(&s->hash_desc);
 631         if (rc) {
 632                 printk(KERN_ERR
 633                        "%s: Error initializing crypto hash; rc = [%d]\n",
 634                        __func__, rc);
 635                 goto out_release_free_unlock;
 636         }
 637         rc = crypto_hash_update(
 638                 &s->hash_desc, &s->hash_sg,
 639                 s->auth_tok->token.password.session_key_encryption_key_bytes);
 640         if (rc) {
 641                 printk(KERN_ERR
 642                        "%s: Error updating crypto hash; rc = [%d]\n",
 643                        __func__, rc);
 644                 goto out_release_free_unlock;
 645         }
 646         rc = crypto_hash_final(&s->hash_desc, s->hash);
 647         if (rc) {
 648                 printk(KERN_ERR
 649                        "%s: Error finalizing crypto hash; rc = [%d]\n",
 650                        __func__, rc);
 651                 goto out_release_free_unlock;
 652         }
 653         for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
 654                 s->block_aligned_filename[s->j] =
 655                         s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
 656                 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
 657                     == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
 658                         sg_init_one(&s->hash_sg, (u8 *)s->hash,
 659                                     ECRYPTFS_TAG_70_DIGEST_SIZE);
 660                         rc = crypto_hash_init(&s->hash_desc);
 661                         if (rc) {
 662                                 printk(KERN_ERR
 663                                        "%s: Error initializing crypto hash; "
 664                                        "rc = [%d]\n", __func__, rc);
 665                                 goto out_release_free_unlock;
 666                         }
 667                         rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
 668                                                 ECRYPTFS_TAG_70_DIGEST_SIZE);
 669                         if (rc) {
 670                                 printk(KERN_ERR
 671                                        "%s: Error updating crypto hash; "
 672                                        "rc = [%d]\n", __func__, rc);
 673                                 goto out_release_free_unlock;
 674                         }
 675                         rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
 676                         if (rc) {
 677                                 printk(KERN_ERR
 678                                        "%s: Error finalizing crypto hash; "
 679                                        "rc = [%d]\n", __func__, rc);
 680                                 goto out_release_free_unlock;
 681                         }
 682                         memcpy(s->hash, s->tmp_hash,
 683                                ECRYPTFS_TAG_70_DIGEST_SIZE);
 684                 }
 685                 if (s->block_aligned_filename[s->j] == '\0')
 686                         s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
 687         }
 688         memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
 689                filename_size);
 690         rc = virt_to_scatterlist(s->block_aligned_filename,
 691                                  s->block_aligned_filename_size, &s->src_sg, 1);
 692         if (rc != 1) {
 693                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 694                        "convert filename memory to scatterlist; "
 695                        "expected rc = 1; got rc = [%d]. "
 696                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 697                        s->block_aligned_filename_size);
 698                 goto out_release_free_unlock;
 699         }
 700         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
 701                                  &s->dst_sg, 1);
 702         if (rc != 1) {
 703                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 704                        "convert encrypted filename memory to scatterlist; "
 705                        "expected rc = 1; got rc = [%d]. "
 706                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 707                        s->block_aligned_filename_size);
 708                 goto out_release_free_unlock;
 709         }
 710         /* The characters in the first block effectively do the job
 711          * of the IV here, so we just use 0's for the IV. Note the
 712          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
 713          * >= ECRYPTFS_MAX_IV_BYTES. */
 714         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
 715         s->desc.info = s->iv;
 716         rc = crypto_blkcipher_setkey(
 717                 s->desc.tfm,
 718                 s->auth_tok->token.password.session_key_encryption_key,
 719                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 720         if (rc < 0) {
 721                 printk(KERN_ERR "%s: Error setting key for crypto context; "
 722                        "rc = [%d]. s->auth_tok->token.password.session_key_"
 723                        "encryption_key = [0x%p]; mount_crypt_stat->"
 724                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
 725                        rc,
 726                        s->auth_tok->token.password.session_key_encryption_key,
 727                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 728                 goto out_release_free_unlock;
 729         }
 730         rc = crypto_blkcipher_encrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
 731                                          s->block_aligned_filename_size);
 732         if (rc) {
 733                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
 734                        "rc = [%d]\n", __func__, rc);
 735                 goto out_release_free_unlock;
 736         }
 737         s->i += s->block_aligned_filename_size;
 738         (*packet_size) = s->i;
 739         (*remaining_bytes) -= (*packet_size);
 740 out_release_free_unlock:
 741         crypto_free_hash(s->hash_desc.tfm);
 742 out_free_unlock:
 743         kzfree(s->block_aligned_filename);
 744 out_unlock:
 745         mutex_unlock(s->tfm_mutex);
 746 out:
 747         kfree(s);
 748         return rc;
 749 }
 750
 751 struct ecryptfs_parse_tag_70_packet_silly_stack {
 752         u8 cipher_code;
 753         size_t max_packet_size;
 754         size_t packet_size_len;
 755         size_t parsed_tag_70_packet_size;
 756         size_t block_aligned_filename_size;
 757         size_t block_size;
 758         size_t i;
 759         struct mutex *tfm_mutex;
 760         char *decrypted_filename;
 761         struct ecryptfs_auth_tok *auth_tok;
 762         struct scatterlist src_sg;
 763         struct scatterlist dst_sg;
 764         struct blkcipher_desc desc;
 765         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
 766         char iv[ECRYPTFS_MAX_IV_BYTES];
 767         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
 768 };
 769
 770 /**
 771  * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
 772  * @filename: This function kmalloc's the memory for the filename
 773  * @filename_size: This function sets this to the amount of memory
 774  *                 kmalloc'd for the filename
 775  * @packet_size: This function sets this to the the number of octets
 776  *               in the packet parsed
 777  * @mount_crypt_stat: The mount-wide cryptographic context
 778  * @data: The memory location containing the start of the tag 70
 779  *        packet
 780  * @max_packet_size: The maximum legal size of the packet to be parsed
 781  *                   from @data
 782  *
 783  * Returns zero on success; non-zero otherwise
 784  */
 785 int
 786 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
 787                              size_t *packet_size,
 788                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
 789                              char *data, size_t max_packet_size)
 790 {
 791         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
 792         int rc = 0;
 793
 794         (*packet_size) = 0;
 795         (*filename_size) = 0;
 796         (*filename) = NULL;
 797         s = kmalloc(sizeof(*s), GFP_KERNEL);
 798         if (!s) {
 799                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
 800                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
 801                 goto out;
 802         }
 803         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 804         if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
 805                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
 806                        "at least [%d]\n", __func__, max_packet_size,
 807                         (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
 808                 rc = -EINVAL;
 809                 goto out;
 810         }
 811         /* Octet 0: Tag 70 identifier
 812          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
 813          *              and block-aligned encrypted filename size)
 814          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
 815          * Octet N2-N3: Cipher identifier (1 octet)
 816          * Octets N3-N4: Block-aligned encrypted filename
 817          *  - Consists of a minimum number of random numbers, a \0
 818          *    separator, and then the filename */
 819         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
 820                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
 821                        "tag [0x%.2x]\n", __func__,
 822                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
 823                 rc = -EINVAL;
 824                 goto out;
 825         }
 826         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
 827                                           &s->parsed_tag_70_packet_size,
 828                                           &s->packet_size_len);
 829         if (rc) {
 830                 printk(KERN_WARNING "%s: Error parsing packet length; "
 831                        "rc = [%d]\n", __func__, rc);
 832                 goto out;
 833         }
 834         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
 835                                           - ECRYPTFS_SIG_SIZE - 1);
 836         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
 837             > max_packet_size) {
 838                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
 839                        "size is [%zd]\n", __func__, max_packet_size,
 840                        (1 + s->packet_size_len + 1
 841                         + s->block_aligned_filename_size));
 842                 rc = -EINVAL;
 843                 goto out;
 844         }
 845         (*packet_size) += s->packet_size_len;
 846         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
 847                         ECRYPTFS_SIG_SIZE);
 848         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 849         (*packet_size) += ECRYPTFS_SIG_SIZE;
 850         s->cipher_code = data[(*packet_size)++];
 851         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
 852         if (rc) {
 853                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
 854                        __func__, s->cipher_code);
 855                 goto out;
 856         }
 857         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
 858                                                         &s->tfm_mutex,
 859                                                         s->cipher_string);
 860         if (unlikely(rc)) {
 861                 printk(KERN_ERR "Internal error whilst attempting to get "
 862                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
 863                        s->cipher_string, rc);
 864                 goto out;
 865         }
 866         mutex_lock(s->tfm_mutex);
 867         rc = virt_to_scatterlist(&data[(*packet_size)],
 868                                  s->block_aligned_filename_size, &s->src_sg, 1);
 869         if (rc != 1) {
 870                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 871                        "convert encrypted filename memory to scatterlist; "
 872                        "expected rc = 1; got rc = [%d]. "
 873                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 874                        s->block_aligned_filename_size);
 875                 goto out_unlock;
 876         }
 877         (*packet_size) += s->block_aligned_filename_size;
 878         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
 879                                         GFP_KERNEL);
 880         if (!s->decrypted_filename) {
 881                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
 882                        "kmalloc [%zd] bytes\n", __func__,
 883                        s->block_aligned_filename_size);
 884                 rc = -ENOMEM;
 885                 goto out_unlock;
 886         }
 887         rc = virt_to_scatterlist(s->decrypted_filename,
 888                                  s->block_aligned_filename_size, &s->dst_sg, 1);
 889         if (rc != 1) {
 890                 printk(KERN_ERR "%s: Internal error whilst attempting to "
 891                        "convert decrypted filename memory to scatterlist; "
 892                        "expected rc = 1; got rc = [%d]. "
 893                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
 894                        s->block_aligned_filename_size);
 895                 goto out_free_unlock;
 896         }
 897         /* The characters in the first block effectively do the job of
 898          * the IV here, so we just use 0's for the IV. Note the
 899          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
 900          * >= ECRYPTFS_MAX_IV_BYTES. */
 901         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
 902         s->desc.info = s->iv;
 903         rc = ecryptfs_find_auth_tok_for_sig(&s->auth_tok, mount_crypt_stat,
 904                                             s->fnek_sig_hex);
 905         if (rc) {
 906                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
 907                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
 908                        rc);
 909                 goto out_free_unlock;
 910         }
 911         /* TODO: Support other key modules than passphrase for
 912          * filename encryption */
 913         BUG_ON(s->auth_tok->token_type != ECRYPTFS_PASSWORD);
 914         rc = crypto_blkcipher_setkey(
 915                 s->desc.tfm,
 916                 s->auth_tok->token.password.session_key_encryption_key,
 917                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
 918         if (rc < 0) {
 919                 printk(KERN_ERR "%s: Error setting key for crypto context; "
 920                        "rc = [%d]. s->auth_tok->token.password.session_key_"
 921                        "encryption_key = [0x%p]; mount_crypt_stat->"
 922                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
 923                        rc,
 924                        s->auth_tok->token.password.session_key_encryption_key,
 925                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 926                 goto out_free_unlock;
 927         }
 928         rc = crypto_blkcipher_decrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
 929                                          s->block_aligned_filename_size);
 930         if (rc) {
 931                 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
 932                        "rc = [%d]\n", __func__, rc);
 933                 goto out_free_unlock;
 934         }
 935         s->i = 0;
 936         while (s->decrypted_filename[s->i] != '\0'
 937                && s->i < s->block_aligned_filename_size)
 938                 s->i++;
 939         if (s->i == s->block_aligned_filename_size) {
 940                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
 941                        "find valid separator between random characters and "
 942                        "the filename\n", __func__);
 943                 rc = -EINVAL;
 944                 goto out_free_unlock;
 945         }
 946         s->i++;
 947         (*filename_size) = (s->block_aligned_filename_size - s->i);
 948         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
 949                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
 950                        "invalid\n", __func__, (*filename_size));
 951                 rc = -EINVAL;
 952                 goto out_free_unlock;
 953         }
 954         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
 955         if (!(*filename)) {
 956                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
 957                        "kmalloc [%zd] bytes\n", __func__,
 958                        ((*filename_size) + 1));
 959                 rc = -ENOMEM;
 960                 goto out_free_unlock;
 961         }
 962         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
 963         (*filename)[(*filename_size)] = '\0';
 964 out_free_unlock:
 965         kfree(s->decrypted_filename);
 966 out_unlock:
 967         mutex_unlock(s->tfm_mutex);
 968 out:
 969         if (rc) {
 970                 (*packet_size) = 0;
 971                 (*filename_size) = 0;
 972                 (*filename) = NULL;
 973         }
 974         kfree(s);
 975         return rc;
 976 }
 977
 978 static int
 979 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
 980 {
 981         int rc = 0;
 982
 983         (*sig) = NULL;
 984         switch (auth_tok->token_type) {
 985         case ECRYPTFS_PASSWORD:
 986                 (*sig) = auth_tok->token.password.signature;
 987                 break;
 988         case ECRYPTFS_PRIVATE_KEY:
 989                 (*sig) = auth_tok->token.private_key.signature;
 990                 break;
 991         default:
 992                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
 993                        auth_tok->token_type);
 994                 rc = -EINVAL;
 995         }
 996         return rc;
 997 }
 998
 999 /**
1000  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1001  * @auth_tok: The key authentication token used to decrypt the session key
1002  * @crypt_stat: The cryptographic context
1003  *
1004  * Returns zero on success; non-zero error otherwise.
1005  */
1006 static int
1007 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1008                                   struct ecryptfs_crypt_stat *crypt_stat)
1009 {
1010         u8 cipher_code = 0;
1011         struct ecryptfs_msg_ctx *msg_ctx;
1012         struct ecryptfs_message *msg = NULL;
1013         char *auth_tok_sig;
1014         char *payload;
1015         size_t payload_len;
1016         int rc;
1017
1018         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1019         if (rc) {
1020                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1021                        auth_tok->token_type);
1022                 goto out;
1023         }
1024         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1025                                  &payload, &payload_len);
1026         if (rc) {
1027                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1028                 goto out;
1029         }
1030         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1031         if (rc) {
1032                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1033                                 "ecryptfsd\n");
1034                 goto out;
1035         }
1036         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1037         if (rc) {
1038                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1039                                 "from the user space daemon\n");
1040                 rc = -EIO;
1041                 goto out;
1042         }
1043         rc = parse_tag_65_packet(&(auth_tok->session_key),
1044                                  &cipher_code, msg);
1045         if (rc) {
1046                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1047                        rc);
1048                 goto out;
1049         }
1050         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1051         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1052                auth_tok->session_key.decrypted_key_size);
1053         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1054         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1055         if (rc) {
1056                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1057                                 cipher_code)
1058                 goto out;
1059         }
1060         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1061         if (ecryptfs_verbosity > 0) {
1062                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1063                 ecryptfs_dump_hex(crypt_stat->key,
1064                                   crypt_stat->key_size);
1065         }
1066 out:
1067         if (msg)
1068                 kfree(msg);
1069         return rc;
1070 }
1071
1072 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1073 {
1074         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1075         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1076
1077         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1078                                  auth_tok_list_head, list) {
1079                 list_del(&auth_tok_list_item->list);
1080                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1081                                 auth_tok_list_item);
1082         }
1083 }
1084
1085 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1086
1087 /**
1088  * parse_tag_1_packet
1089  * @crypt_stat: The cryptographic context to modify based on packet contents
1090  * @data: The raw bytes of the packet.
1091  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1092  *                 a new authentication token will be placed at the
1093  *                 end of this list for this packet.
1094  * @new_auth_tok: Pointer to a pointer to memory that this function
1095  *                allocates; sets the memory address of the pointer to
1096  *                NULL on error. This object is added to the
1097  *                auth_tok_list.
1098  * @packet_size: This function writes the size of the parsed packet
1099  *               into this memory location; zero on error.
1100  * @max_packet_size: The maximum allowable packet size
1101  *
1102  * Returns zero on success; non-zero on error.
1103  */
1104 static int
1105 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1106                    unsigned char *data, struct list_head *auth_tok_list,
1107                    struct ecryptfs_auth_tok **new_auth_tok,
1108                    size_t *packet_size, size_t max_packet_size)
1109 {
1110         size_t body_size;
1111         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1112         size_t length_size;
1113         int rc = 0;
1114
1115         (*packet_size) = 0;
1116         (*new_auth_tok) = NULL;
1117         /**
1118          * This format is inspired by OpenPGP; see RFC 2440
1119          * packet tag 1
1120          *
1121          * Tag 1 identifier (1 byte)
1122          * Max Tag 1 packet size (max 3 bytes)
1123          * Version (1 byte)
1124          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1125          * Cipher identifier (1 byte)
1126          * Encrypted key size (arbitrary)
1127          *
1128          * 12 bytes minimum packet size
1129          */
1130         if (unlikely(max_packet_size < 12)) {
1131                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1132                 rc = -EINVAL;
1133                 goto out;
1134         }
1135         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1136                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1137                        ECRYPTFS_TAG_1_PACKET_TYPE);
1138                 rc = -EINVAL;
1139                 goto out;
1140         }
1141         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1142          * at end of function upon failure */
1143         auth_tok_list_item =
1144                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1145                                   GFP_KERNEL);
1146         if (!auth_tok_list_item) {
1147                 printk(KERN_ERR "Unable to allocate memory\n");
1148                 rc = -ENOMEM;
1149                 goto out;
1150         }
1151         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1152         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1153                                           &length_size);
1154         if (rc) {
1155                 printk(KERN_WARNING "Error parsing packet length; "
1156                        "rc = [%d]\n", rc);
1157                 goto out_free;
1158         }
1159         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1160                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1161                 rc = -EINVAL;
1162                 goto out_free;
1163         }
1164         (*packet_size) += length_size;
1165         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1166                 printk(KERN_WARNING "Packet size exceeds max\n");
1167                 rc = -EINVAL;
1168                 goto out_free;
1169         }
1170         if (unlikely(data[(*packet_size)++] != 0x03)) {
1171                 printk(KERN_WARNING "Unknown version number [%d]\n",
1172                        data[(*packet_size) - 1]);
1173                 rc = -EINVAL;
1174                 goto out_free;
1175         }
1176         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1177                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1178         *packet_size += ECRYPTFS_SIG_SIZE;
1179         /* This byte is skipped because the kernel does not need to
1180          * know which public key encryption algorithm was used */
1181         (*packet_size)++;
1182         (*new_auth_tok)->session_key.encrypted_key_size =
1183                 body_size - (ECRYPTFS_SIG_SIZE + 2);
1184         if ((*new_auth_tok)->session_key.encrypted_key_size
1185             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1186                 printk(KERN_WARNING "Tag 1 packet contains key larger "
1187                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1188                 rc = -EINVAL;
1189                 goto out;
1190         }
1191         memcpy((*new_auth_tok)->session_key.encrypted_key,
1192                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1193         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1194         (*new_auth_tok)->session_key.flags &=
1195                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1196         (*new_auth_tok)->session_key.flags |=
1197                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1198         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1199         (*new_auth_tok)->flags = 0;
1200         (*new_auth_tok)->session_key.flags &=
1201                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1202         (*new_auth_tok)->session_key.flags &=
1203                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1204         list_add(&auth_tok_list_item->list, auth_tok_list);
1205         goto out;
1206 out_free:
1207         (*new_auth_tok) = NULL;
1208         memset(auth_tok_list_item, 0,
1209                sizeof(struct ecryptfs_auth_tok_list_item));
1210         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1211                         auth_tok_list_item);
1212 out:
1213         if (rc)
1214                 (*packet_size) = 0;
1215         return rc;
1216 }
1217
1218 /**
1219  * parse_tag_3_packet
1220  * @crypt_stat: The cryptographic context to modify based on packet
1221  *              contents.
1222  * @data: The raw bytes of the packet.
1223  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1224  *                 a new authentication token will be placed at the end
1225  *                 of this list for this packet.
1226  * @new_auth_tok: Pointer to a pointer to memory that this function
1227  *                allocates; sets the memory address of the pointer to
1228  *                NULL on error. This object is added to the
1229  *                auth_tok_list.
1230  * @packet_size: This function writes the size of the parsed packet
1231  *               into this memory location; zero on error.
1232  * @max_packet_size: maximum number of bytes to parse
1233  *
1234  * Returns zero on success; non-zero on error.
1235  */
1236 static int
1237 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1238                    unsigned char *data, struct list_head *auth_tok_list,
1239                    struct ecryptfs_auth_tok **new_auth_tok,
1240                    size_t *packet_size, size_t max_packet_size)
1241 {
1242         size_t body_size;
1243         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1244         size_t length_size;
1245         int rc = 0;
1246
1247         (*packet_size) = 0;
1248         (*new_auth_tok) = NULL;
1249         /**
1250          *This format is inspired by OpenPGP; see RFC 2440
1251          * packet tag 3
1252          *
1253          * Tag 3 identifier (1 byte)
1254          * Max Tag 3 packet size (max 3 bytes)
1255          * Version (1 byte)
1256          * Cipher code (1 byte)
1257          * S2K specifier (1 byte)
1258          * Hash identifier (1 byte)
1259          * Salt (ECRYPTFS_SALT_SIZE)
1260          * Hash iterations (1 byte)
1261          * Encrypted key (arbitrary)
1262          *
1263          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1264          */
1265         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1266                 printk(KERN_ERR "Max packet size too large\n");
1267                 rc = -EINVAL;
1268                 goto out;
1269         }
1270         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1271                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1272                        ECRYPTFS_TAG_3_PACKET_TYPE);
1273                 rc = -EINVAL;
1274                 goto out;
1275         }
1276         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1277          * at end of function upon failure */
1278         auth_tok_list_item =
1279             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1280         if (!auth_tok_list_item) {
1281                 printk(KERN_ERR "Unable to allocate memory\n");
1282                 rc = -ENOMEM;
1283                 goto out;
1284         }
1285         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1286         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1287                                           &length_size);
1288         if (rc) {
1289                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1290                        rc);
1291                 goto out_free;
1292         }
1293         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1294                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1295                 rc = -EINVAL;
1296                 goto out_free;
1297         }
1298         (*packet_size) += length_size;
1299         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1300                 printk(KERN_ERR "Packet size exceeds max\n");
1301                 rc = -EINVAL;
1302                 goto out_free;
1303         }
1304         (*new_auth_tok)->session_key.encrypted_key_size =
1305                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1306         if ((*new_auth_tok)->session_key.encrypted_key_size
1307             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1308                 printk(KERN_WARNING "Tag 3 packet contains key larger "
1309                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1310                 rc = -EINVAL;
1311                 goto out_free;
1312         }
1313         if (unlikely(data[(*packet_size)++] != 0x04)) {
1314                 printk(KERN_WARNING "Unknown version number [%d]\n",
1315                        data[(*packet_size) - 1]);
1316                 rc = -EINVAL;
1317                 goto out_free;
1318         }
1319         ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1320                                        (u16)data[(*packet_size)]);
1321         /* A little extra work to differentiate among the AES key
1322          * sizes; see RFC2440 */
1323         switch(data[(*packet_size)++]) {
1324         case RFC2440_CIPHER_AES_192:
1325                 crypt_stat->key_size = 24;
1326                 break;
1327         default:
1328                 crypt_stat->key_size =
1329                         (*new_auth_tok)->session_key.encrypted_key_size;
1330         }
1331         ecryptfs_init_crypt_ctx(crypt_stat);
1332         if (unlikely(data[(*packet_size)++] != 0x03)) {
1333                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1334                 rc = -ENOSYS;
1335                 goto out_free;
1336         }
1337         /* TODO: finish the hash mapping */
1338         switch (data[(*packet_size)++]) {
1339         case 0x01: /* See RFC2440 for these numbers and their mappings */
1340                 /* Choose MD5 */
1341                 memcpy((*new_auth_tok)->token.password.salt,
1342                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1343                 (*packet_size) += ECRYPTFS_SALT_SIZE;
1344                 /* This conversion was taken straight from RFC2440 */
1345                 (*new_auth_tok)->token.password.hash_iterations =
1346                         ((u32) 16 + (data[(*packet_size)] & 15))
1347                                 << ((data[(*packet_size)] >> 4) + 6);
1348                 (*packet_size)++;
1349                 /* Friendly reminder:
1350                  * (*new_auth_tok)->session_key.encrypted_key_size =
1351                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1352                 memcpy((*new_auth_tok)->session_key.encrypted_key,
1353                        &data[(*packet_size)],
1354                        (*new_auth_tok)->session_key.encrypted_key_size);
1355                 (*packet_size) +=
1356                         (*new_auth_tok)->session_key.encrypted_key_size;
1357                 (*new_auth_tok)->session_key.flags &=
1358                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1359                 (*new_auth_tok)->session_key.flags |=
1360                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1361                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1362                 break;
1363         default:
1364                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1365                                 "[%d]\n", data[(*packet_size) - 1]);
1366                 rc = -ENOSYS;
1367                 goto out_free;
1368         }
1369         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1370         /* TODO: Parametarize; we might actually want userspace to
1371          * decrypt the session key. */
1372         (*new_auth_tok)->session_key.flags &=
1373                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1374         (*new_auth_tok)->session_key.flags &=
1375                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1376         list_add(&auth_tok_list_item->list, auth_tok_list);
1377         goto out;
1378 out_free:
1379         (*new_auth_tok) = NULL;
1380         memset(auth_tok_list_item, 0,
1381                sizeof(struct ecryptfs_auth_tok_list_item));
1382         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1383                         auth_tok_list_item);
1384 out:
1385         if (rc)
1386                 (*packet_size) = 0;
1387         return rc;
1388 }
1389
1390 /**
1391  * parse_tag_11_packet
1392  * @data: The raw bytes of the packet
1393  * @contents: This function writes the data contents of the literal
1394  *            packet into this memory location
1395  * @max_contents_bytes: The maximum number of bytes that this function
1396  *                      is allowed to write into contents
1397  * @tag_11_contents_size: This function writes the size of the parsed
1398  *                        contents into this memory location; zero on
1399  *                        error
1400  * @packet_size: This function writes the size of the parsed packet
1401  *               into this memory location; zero on error
1402  * @max_packet_size: maximum number of bytes to parse
1403  *
1404  * Returns zero on success; non-zero on error.
1405  */
1406 static int
1407 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1408                     size_t max_contents_bytes, size_t *tag_11_contents_size,
1409                     size_t *packet_size, size_t max_packet_size)
1410 {
1411         size_t body_size;
1412         size_t length_size;
1413         int rc = 0;
1414
1415         (*packet_size) = 0;
1416         (*tag_11_contents_size) = 0;
1417         /* This format is inspired by OpenPGP; see RFC 2440
1418          * packet tag 11
1419          *
1420          * Tag 11 identifier (1 byte)
1421          * Max Tag 11 packet size (max 3 bytes)
1422          * Binary format specifier (1 byte)
1423          * Filename length (1 byte)
1424          * Filename ("_CONSOLE") (8 bytes)
1425          * Modification date (4 bytes)
1426          * Literal data (arbitrary)
1427          *
1428          * We need at least 16 bytes of data for the packet to even be
1429          * valid.
1430          */
1431         if (max_packet_size < 16) {
1432                 printk(KERN_ERR "Maximum packet size too small\n");
1433                 rc = -EINVAL;
1434                 goto out;
1435         }
1436         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1437                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1438                 rc = -EINVAL;
1439                 goto out;
1440         }
1441         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1442                                           &length_size);
1443         if (rc) {
1444                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1445                 goto out;
1446         }
1447         if (body_size < 14) {
1448                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1449                 rc = -EINVAL;
1450                 goto out;
1451         }
1452         (*packet_size) += length_size;
1453         (*tag_11_contents_size) = (body_size - 14);
1454         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1455                 printk(KERN_ERR "Packet size exceeds max\n");
1456                 rc = -EINVAL;
1457                 goto out;
1458         }
1459         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1460                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1461                        "expected size\n");
1462                 rc = -EINVAL;
1463                 goto out;
1464         }
1465         if (data[(*packet_size)++] != 0x62) {
1466                 printk(KERN_WARNING "Unrecognizable packet\n");
1467                 rc = -EINVAL;
1468                 goto out;
1469         }
1470         if (data[(*packet_size)++] != 0x08) {
1471                 printk(KERN_WARNING "Unrecognizable packet\n");
1472                 rc = -EINVAL;
1473                 goto out;
1474         }
1475         (*packet_size) += 12; /* Ignore filename and modification date */
1476         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1477         (*packet_size) += (*tag_11_contents_size);
1478 out:
1479         if (rc) {
1480                 (*packet_size) = 0;
1481                 (*tag_11_contents_size) = 0;
1482         }
1483         return rc;
1484 }
1485
1486 /**
1487  * ecryptfs_verify_version
1488  * @version: The version number to confirm
1489  *
1490  * Returns zero on good version; non-zero otherwise
1491  */
1492 static int ecryptfs_verify_version(u16 version)
1493 {
1494         int rc = 0;
1495         unsigned char major;
1496         unsigned char minor;
1497
1498         major = ((version >> 8) & 0xFF);
1499         minor = (version & 0xFF);
1500         if (major != ECRYPTFS_VERSION_MAJOR) {
1501                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
1502                                 "Expected [%d]; got [%d]\n",
1503                                 ECRYPTFS_VERSION_MAJOR, major);
1504                 rc = -EINVAL;
1505                 goto out;
1506         }
1507         if (minor != ECRYPTFS_VERSION_MINOR) {
1508                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
1509                                 "Expected [%d]; got [%d]\n",
1510                                 ECRYPTFS_VERSION_MINOR, minor);
1511                 rc = -EINVAL;
1512                 goto out;
1513         }
1514 out:
1515         return rc;
1516 }
1517
1518 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1519                                       struct ecryptfs_auth_tok **auth_tok,
1520                                       char *sig)
1521 {
1522         int rc = 0;
1523
1524         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1525         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1526                 printk(KERN_ERR "Could not find key with description: [%s]\n",
1527                        sig);
1528                 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1529                 goto out;
1530         }
1531         (*auth_tok) = ecryptfs_get_key_payload_data(*auth_tok_key);
1532         if (ecryptfs_verify_version((*auth_tok)->version)) {
1533                 printk(KERN_ERR
1534                        "Data structure version mismatch. "
1535                        "Userspace tools must match eCryptfs "
1536                        "kernel module with major version [%d] "
1537                        "and minor version [%d]\n",
1538                        ECRYPTFS_VERSION_MAJOR,
1539                        ECRYPTFS_VERSION_MINOR);
1540                 rc = -EINVAL;
1541                 goto out;
1542         }
1543         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
1544             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
1545                 printk(KERN_ERR "Invalid auth_tok structure "
1546                        "returned from key query\n");
1547                 rc = -EINVAL;
1548                 goto out;
1549         }
1550 out:
1551         return rc;
1552 }
1553
1554 /**
1555  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1556  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1557  * @crypt_stat: The cryptographic context
1558  *
1559  * Returns zero on success; non-zero error otherwise
1560  */
1561 static int
1562 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1563                                          struct ecryptfs_crypt_stat *crypt_stat)
1564 {
1565         struct scatterlist dst_sg[2];
1566         struct scatterlist src_sg[2];
1567         struct mutex *tfm_mutex;
1568         struct blkcipher_desc desc = {
1569                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1570         };
1571         int rc = 0;
1572
1573         if (unlikely(ecryptfs_verbosity > 0)) {
1574                 ecryptfs_printk(
1575                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1576                         auth_tok->token.password.session_key_encryption_key_bytes);
1577                 ecryptfs_dump_hex(
1578                         auth_tok->token.password.session_key_encryption_key,
1579                         auth_tok->token.password.session_key_encryption_key_bytes);
1580         }
1581         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1582                                                         crypt_stat->cipher);
1583         if (unlikely(rc)) {
1584                 printk(KERN_ERR "Internal error whilst attempting to get "
1585                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1586                        crypt_stat->cipher, rc);
1587                 goto out;
1588         }
1589         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1590                                  auth_tok->session_key.encrypted_key_size,
1591                                  src_sg, 2);
1592         if (rc < 1 || rc > 2) {
1593                 printk(KERN_ERR "Internal error whilst attempting to convert "
1594                         "auth_tok->session_key.encrypted_key to scatterlist; "
1595                         "expected rc = 1; got rc = [%d]. "
1596                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1597                         auth_tok->session_key.encrypted_key_size);
1598                 goto out;
1599         }
1600         auth_tok->session_key.decrypted_key_size =
1601                 auth_tok->session_key.encrypted_key_size;
1602         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1603                                  auth_tok->session_key.decrypted_key_size,
1604                                  dst_sg, 2);
1605         if (rc < 1 || rc > 2) {
1606                 printk(KERN_ERR "Internal error whilst attempting to convert "
1607                         "auth_tok->session_key.decrypted_key to scatterlist; "
1608                         "expected rc = 1; got rc = [%d]\n", rc);
1609                 goto out;
1610         }
1611         mutex_lock(tfm_mutex);
1612         rc = crypto_blkcipher_setkey(
1613                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1614                 crypt_stat->key_size);
1615         if (unlikely(rc < 0)) {
1616                 mutex_unlock(tfm_mutex);
1617                 printk(KERN_ERR "Error setting key for crypto context\n");
1618                 rc = -EINVAL;
1619                 goto out;
1620         }
1621         rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1622                                       auth_tok->session_key.encrypted_key_size);
1623         mutex_unlock(tfm_mutex);
1624         if (unlikely(rc)) {
1625                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1626                 goto out;
1627         }
1628         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1629         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1630                auth_tok->session_key.decrypted_key_size);
1631         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1632         if (unlikely(ecryptfs_verbosity > 0)) {
1633                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%d]:\n",
1634                                 crypt_stat->key_size);
1635                 ecryptfs_dump_hex(crypt_stat->key,
1636                                   crypt_stat->key_size);
1637         }
1638 out:
1639         return rc;
1640 }
1641
1642 /**
1643  * ecryptfs_parse_packet_set
1644  * @crypt_stat: The cryptographic context
1645  * @src: Virtual address of region of memory containing the packets
1646  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1647  *
1648  * Get crypt_stat to have the file's session key if the requisite key
1649  * is available to decrypt the session key.
1650  *
1651  * Returns Zero if a valid authentication token was retrieved and
1652  * processed; negative value for file not encrypted or for error
1653  * conditions.
1654  */
1655 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1656                               unsigned char *src,
1657                               struct dentry *ecryptfs_dentry)
1658 {
1659         size_t i = 0;
1660         size_t found_auth_tok;
1661         size_t next_packet_is_auth_tok_packet;
1662         struct list_head auth_tok_list;
1663         struct ecryptfs_auth_tok *matching_auth_tok;
1664         struct ecryptfs_auth_tok *candidate_auth_tok;
1665         char *candidate_auth_tok_sig;
1666         size_t packet_size;
1667         struct ecryptfs_auth_tok *new_auth_tok;
1668         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1669         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1670         size_t tag_11_contents_size;
1671         size_t tag_11_packet_size;
1672         int rc = 0;
1673
1674         INIT_LIST_HEAD(&auth_tok_list);
1675         /* Parse the header to find as many packets as we can; these will be
1676          * added the our &auth_tok_list */
1677         next_packet_is_auth_tok_packet = 1;
1678         while (next_packet_is_auth_tok_packet) {
1679                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1680
1681                 switch (src[i]) {
1682                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1683                         rc = parse_tag_3_packet(crypt_stat,
1684                                                 (unsigned char *)&src[i],
1685                                                 &auth_tok_list, &new_auth_tok,
1686                                                 &packet_size, max_packet_size);
1687                         if (rc) {
1688                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1689                                                 "tag 3 packet\n");
1690                                 rc = -EIO;
1691                                 goto out_wipe_list;
1692                         }
1693                         i += packet_size;
1694                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1695                                                  sig_tmp_space,
1696                                                  ECRYPTFS_SIG_SIZE,
1697                                                  &tag_11_contents_size,
1698                                                  &tag_11_packet_size,
1699                                                  max_packet_size);
1700                         if (rc) {
1701                                 ecryptfs_printk(KERN_ERR, "No valid "
1702                                                 "(ecryptfs-specific) literal "
1703                                                 "packet containing "
1704                                                 "authentication token "
1705                                                 "signature found after "
1706                                                 "tag 3 packet\n");
1707                                 rc = -EIO;
1708                                 goto out_wipe_list;
1709                         }
1710                         i += tag_11_packet_size;
1711                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1712                                 ecryptfs_printk(KERN_ERR, "Expected "
1713                                                 "signature of size [%d]; "
1714                                                 "read size [%d]\n",
1715                                                 ECRYPTFS_SIG_SIZE,
1716                                                 tag_11_contents_size);
1717                                 rc = -EIO;
1718                                 goto out_wipe_list;
1719                         }
1720                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1721                                         sig_tmp_space, tag_11_contents_size);
1722                         new_auth_tok->token.password.signature[
1723                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1724                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1725                         break;
1726                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1727                         rc = parse_tag_1_packet(crypt_stat,
1728                                                 (unsigned char *)&src[i],
1729                                                 &auth_tok_list, &new_auth_tok,
1730                                                 &packet_size, max_packet_size);
1731                         if (rc) {
1732                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1733                                                 "tag 1 packet\n");
1734                                 rc = -EIO;
1735                                 goto out_wipe_list;
1736                         }
1737                         i += packet_size;
1738                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1739                         break;
1740                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1741                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1742                                         "(Tag 11 not allowed by itself)\n");
1743                         rc = -EIO;
1744                         goto out_wipe_list;
1745                         break;
1746                 default:
1747                         ecryptfs_printk(KERN_DEBUG, "No packet at offset "
1748                                         "[%d] of the file header; hex value of "
1749                                         "character is [0x%.2x]\n", i, src[i]);
1750                         next_packet_is_auth_tok_packet = 0;
1751                 }
1752         }
1753         if (list_empty(&auth_tok_list)) {
1754                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1755                        "eCryptfs file; this is not supported in this version "
1756                        "of the eCryptfs kernel module\n");
1757                 rc = -EINVAL;
1758                 goto out;
1759         }
1760         /* auth_tok_list contains the set of authentication tokens
1761          * parsed from the metadata. We need to find a matching
1762          * authentication token that has the secret component(s)
1763          * necessary to decrypt the EFEK in the auth_tok parsed from
1764          * the metadata. There may be several potential matches, but
1765          * just one will be sufficient to decrypt to get the FEK. */
1766 find_next_matching_auth_tok:
1767         found_auth_tok = 0;
1768         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1769                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1770                 if (unlikely(ecryptfs_verbosity > 0)) {
1771                         ecryptfs_printk(KERN_DEBUG,
1772                                         "Considering cadidate auth tok:\n");
1773                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1774                 }
1775                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1776                                                candidate_auth_tok);
1777                 if (rc) {
1778                         printk(KERN_ERR
1779                                "Unrecognized candidate auth tok type: [%d]\n",
1780                                candidate_auth_tok->token_type);
1781                         rc = -EINVAL;
1782                         goto out_wipe_list;
1783                 }
1784                 ecryptfs_find_auth_tok_for_sig(&matching_auth_tok,
1785                                                crypt_stat->mount_crypt_stat,
1786                                                candidate_auth_tok_sig);
1787                 if (matching_auth_tok) {
1788                         found_auth_tok = 1;
1789                         goto found_matching_auth_tok;
1790                 }
1791         }
1792         if (!found_auth_tok) {
1793                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1794                                 "authentication token\n");
1795                 rc = -EIO;
1796                 goto out_wipe_list;
1797         }
1798 found_matching_auth_tok:
1799         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1800                 memcpy(&(candidate_auth_tok->token.private_key),
1801                        &(matching_auth_tok->token.private_key),
1802                        sizeof(struct ecryptfs_private_key));
1803                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1804                                                        crypt_stat);
1805         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1806                 memcpy(&(candidate_auth_tok->token.password),
1807                        &(matching_auth_tok->token.password),
1808                        sizeof(struct ecryptfs_password));
1809                 rc = decrypt_passphrase_encrypted_session_key(
1810                         candidate_auth_tok, crypt_stat);
1811         }
1812         if (rc) {
1813                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1814
1815                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1816                                 "session key for authentication token with sig "
1817                                 "[%.*s]; rc = [%d]. Removing auth tok "
1818                                 "candidate from the list and searching for "
1819                                 "the next match.\n", candidate_auth_tok_sig,
1820                                 ECRYPTFS_SIG_SIZE_HEX, rc);
1821                 list_for_each_entry_safe(auth_tok_list_item,
1822                                          auth_tok_list_item_tmp,
1823                                          &auth_tok_list, list) {
1824                         if (candidate_auth_tok
1825                             == &auth_tok_list_item->auth_tok) {
1826                                 list_del(&auth_tok_list_item->list);
1827                                 kmem_cache_free(
1828                                         ecryptfs_auth_tok_list_item_cache,
1829                                         auth_tok_list_item);
1830                                 goto find_next_matching_auth_tok;
1831                         }
1832                 }
1833                 BUG();
1834         }
1835         rc = ecryptfs_compute_root_iv(crypt_stat);
1836         if (rc) {
1837                 ecryptfs_printk(KERN_ERR, "Error computing "
1838                                 "the root IV\n");
1839                 goto out_wipe_list;
1840         }
1841         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1842         if (rc) {
1843                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1844                                 "context for cipher [%s]; rc = [%d]\n",
1845                                 crypt_stat->cipher, rc);
1846         }
1847 out_wipe_list:
1848         wipe_auth_tok_list(&auth_tok_list);
1849 out:
1850         return rc;
1851 }
1852
1853 static int
1854 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1855                         struct ecryptfs_crypt_stat *crypt_stat,
1856                         struct ecryptfs_key_record *key_rec)
1857 {
1858         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1859         char *payload = NULL;
1860         size_t payload_len;
1861         struct ecryptfs_message *msg;
1862         int rc;
1863
1864         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1865                                  ecryptfs_code_for_cipher_string(
1866                                          crypt_stat->cipher,
1867                                          crypt_stat->key_size),
1868                                  crypt_stat, &payload, &payload_len);
1869         if (rc) {
1870                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1871                 goto out;
1872         }
1873         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1874         if (rc) {
1875                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1876                                 "ecryptfsd\n");
1877                 goto out;
1878         }
1879         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1880         if (rc) {
1881                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1882                                 "from the user space daemon\n");
1883                 rc = -EIO;
1884                 goto out;
1885         }
1886         rc = parse_tag_67_packet(key_rec, msg);
1887         if (rc)
1888                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1889         kfree(msg);
1890 out:
1891         kfree(payload);
1892         return rc;
1893 }
1894 /**
1895  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
1896  * @dest: Buffer into which to write the packet
1897  * @remaining_bytes: Maximum number of bytes that can be writtn
1898  * @auth_tok: The authentication token used for generating the tag 1 packet
1899  * @crypt_stat: The cryptographic context
1900  * @key_rec: The key record struct for the tag 1 packet
1901  * @packet_size: This function will write the number of bytes that end
1902  *               up constituting the packet; set to zero on error
1903  *
1904  * Returns zero on success; non-zero on error.
1905  */
1906 static int
1907 write_tag_1_packet(char *dest, size_t *remaining_bytes,
1908                    struct ecryptfs_auth_tok *auth_tok,
1909                    struct ecryptfs_crypt_stat *crypt_stat,
1910                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
1911 {
1912         size_t i;
1913         size_t encrypted_session_key_valid = 0;
1914         size_t packet_size_length;
1915         size_t max_packet_size;
1916         int rc = 0;
1917
1918         (*packet_size) = 0;
1919         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
1920                           ECRYPTFS_SIG_SIZE);
1921         encrypted_session_key_valid = 0;
1922         for (i = 0; i < crypt_stat->key_size; i++)
1923                 encrypted_session_key_valid |=
1924                         auth_tok->session_key.encrypted_key[i];
1925         if (encrypted_session_key_valid) {
1926                 memcpy(key_rec->enc_key,
1927                        auth_tok->session_key.encrypted_key,
1928                        auth_tok->session_key.encrypted_key_size);
1929                 goto encrypted_session_key_set;
1930         }
1931         if (auth_tok->session_key.encrypted_key_size == 0)
1932                 auth_tok->session_key.encrypted_key_size =
1933                         auth_tok->token.private_key.key_size;
1934         rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
1935         if (rc) {
1936                 printk(KERN_ERR "Failed to encrypt session key via a key "
1937                        "module; rc = [%d]\n", rc);
1938                 goto out;
1939         }
1940         if (ecryptfs_verbosity > 0) {
1941                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
1942                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
1943         }
1944 encrypted_session_key_set:
1945         /* This format is inspired by OpenPGP; see RFC 2440
1946          * packet tag 1 */
1947         max_packet_size = (1                         /* Tag 1 identifier */
1948                            + 3                       /* Max Tag 1 packet size */
1949                            + 1                       /* Version */
1950                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
1951                            + 1                       /* Cipher identifier */
1952                            + key_rec->enc_key_size); /* Encrypted key size */
1953         if (max_packet_size > (*remaining_bytes)) {
1954                 printk(KERN_ERR "Packet length larger than maximum allowable; "
1955                        "need up to [%td] bytes, but there are only [%td] "
1956                        "available\n", max_packet_size, (*remaining_bytes));
1957                 rc = -EINVAL;
1958                 goto out;
1959         }
1960         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
1961         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
1962                                           (max_packet_size - 4),
1963                                           &packet_size_length);
1964         if (rc) {
1965                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
1966                                 "header; cannot generate packet length\n");
1967                 goto out;
1968         }
1969         (*packet_size) += packet_size_length;
1970         dest[(*packet_size)++] = 0x03; /* version 3 */
1971         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
1972         (*packet_size) += ECRYPTFS_SIG_SIZE;
1973         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
1974         memcpy(&dest[(*packet_size)], key_rec->enc_key,
1975                key_rec->enc_key_size);
1976         (*packet_size) += key_rec->enc_key_size;
1977 out:
1978         if (rc)
1979                 (*packet_size) = 0;
1980         else
1981                 (*remaining_bytes) -= (*packet_size);
1982         return rc;
1983 }
1984
1985 /**
1986  * write_tag_11_packet
1987  * @dest: Target into which Tag 11 packet is to be written
1988  * @remaining_bytes: Maximum packet length
1989  * @contents: Byte array of contents to copy in
1990  * @contents_length: Number of bytes in contents
1991  * @packet_length: Length of the Tag 11 packet written; zero on error
1992  *
1993  * Returns zero on success; non-zero on error.
1994  */
1995 static int
1996 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
1997                     size_t contents_length, size_t *packet_length)
1998 {
1999         size_t packet_size_length;
2000         size_t max_packet_size;
2001         int rc = 0;
2002
2003         (*packet_length) = 0;
2004         /* This format is inspired by OpenPGP; see RFC 2440
2005          * packet tag 11 */
2006         max_packet_size = (1                   /* Tag 11 identifier */
2007                            + 3                 /* Max Tag 11 packet size */
2008                            + 1                 /* Binary format specifier */
2009                            + 1                 /* Filename length */
2010                            + 8                 /* Filename ("_CONSOLE") */
2011                            + 4                 /* Modification date */
2012                            + contents_length); /* Literal data */
2013         if (max_packet_size > (*remaining_bytes)) {
2014                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2015                        "need up to [%td] bytes, but there are only [%td] "
2016                        "available\n", max_packet_size, (*remaining_bytes));
2017                 rc = -EINVAL;
2018                 goto out;
2019         }
2020         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2021         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2022                                           (max_packet_size - 4),
2023                                           &packet_size_length);
2024         if (rc) {
2025                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2026                        "generate packet length. rc = [%d]\n", rc);
2027                 goto out;
2028         }
2029         (*packet_length) += packet_size_length;
2030         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2031         dest[(*packet_length)++] = 8;
2032         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2033         (*packet_length) += 8;
2034         memset(&dest[(*packet_length)], 0x00, 4);
2035         (*packet_length) += 4;
2036         memcpy(&dest[(*packet_length)], contents, contents_length);
2037         (*packet_length) += contents_length;
2038  out:
2039         if (rc)
2040                 (*packet_length) = 0;
2041         else
2042                 (*remaining_bytes) -= (*packet_length);
2043         return rc;
2044 }
2045
2046 /**
2047  * write_tag_3_packet
2048  * @dest: Buffer into which to write the packet
2049  * @remaining_bytes: Maximum number of bytes that can be written
2050  * @auth_tok: Authentication token
2051  * @crypt_stat: The cryptographic context
2052  * @key_rec: encrypted key
2053  * @packet_size: This function will write the number of bytes that end
2054  *               up constituting the packet; set to zero on error
2055  *
2056  * Returns zero on success; non-zero on error.
2057  */
2058 static int
2059 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2060                    struct ecryptfs_auth_tok *auth_tok,
2061                    struct ecryptfs_crypt_stat *crypt_stat,
2062                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2063 {
2064         size_t i;
2065         size_t encrypted_session_key_valid = 0;
2066         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2067         struct scatterlist dst_sg[2];
2068         struct scatterlist src_sg[2];
2069         struct mutex *tfm_mutex = NULL;
2070         u8 cipher_code;
2071         size_t packet_size_length;
2072         size_t max_packet_size;
2073         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2074                 crypt_stat->mount_crypt_stat;
2075         struct blkcipher_desc desc = {
2076                 .tfm = NULL,
2077                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2078         };
2079         int rc = 0;
2080
2081         (*packet_size) = 0;
2082         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2083                           ECRYPTFS_SIG_SIZE);
2084         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2085                                                         crypt_stat->cipher);
2086         if (unlikely(rc)) {
2087                 printk(KERN_ERR "Internal error whilst attempting to get "
2088                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2089                        crypt_stat->cipher, rc);
2090                 goto out;
2091         }
2092         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2093                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2094
2095                 printk(KERN_WARNING "No key size specified at mount; "
2096                        "defaulting to [%d]\n", alg->max_keysize);
2097                 mount_crypt_stat->global_default_cipher_key_size =
2098                         alg->max_keysize;
2099         }
2100         if (crypt_stat->key_size == 0)
2101                 crypt_stat->key_size =
2102                         mount_crypt_stat->global_default_cipher_key_size;
2103         if (auth_tok->session_key.encrypted_key_size == 0)
2104                 auth_tok->session_key.encrypted_key_size =
2105                         crypt_stat->key_size;
2106         if (crypt_stat->key_size == 24
2107             && strcmp("aes", crypt_stat->cipher) == 0) {
2108                 memset((crypt_stat->key + 24), 0, 8);
2109                 auth_tok->session_key.encrypted_key_size = 32;
2110         } else
2111                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2112         key_rec->enc_key_size =
2113                 auth_tok->session_key.encrypted_key_size;
2114         encrypted_session_key_valid = 0;
2115         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2116                 encrypted_session_key_valid |=
2117                         auth_tok->session_key.encrypted_key[i];
2118         if (encrypted_session_key_valid) {
2119                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2120                                 "using auth_tok->session_key.encrypted_key, "
2121                                 "where key_rec->enc_key_size = [%d]\n",
2122                                 key_rec->enc_key_size);
2123                 memcpy(key_rec->enc_key,
2124                        auth_tok->session_key.encrypted_key,
2125                        key_rec->enc_key_size);
2126                 goto encrypted_session_key_set;
2127         }
2128         if (auth_tok->token.password.flags &
2129             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2130                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2131                                 "session key encryption key of size [%d]\n",
2132                                 auth_tok->token.password.
2133                                 session_key_encryption_key_bytes);
2134                 memcpy(session_key_encryption_key,
2135                        auth_tok->token.password.session_key_encryption_key,
2136                        crypt_stat->key_size);
2137                 ecryptfs_printk(KERN_DEBUG,
2138                                 "Cached session key " "encryption key: \n");
2139                 if (ecryptfs_verbosity > 0)
2140                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2141         }
2142         if (unlikely(ecryptfs_verbosity > 0)) {
2143                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2144                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2145         }
2146         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2147                                  src_sg, 2);
2148         if (rc < 1 || rc > 2) {
2149                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2150                                 "for crypt_stat session key; expected rc = 1; "
2151                                 "got rc = [%d]. key_rec->enc_key_size = [%d]\n",
2152                                 rc, key_rec->enc_key_size);
2153                 rc = -ENOMEM;
2154                 goto out;
2155         }
2156         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2157                                  dst_sg, 2);
2158         if (rc < 1 || rc > 2) {
2159                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2160                                 "for crypt_stat encrypted session key; "
2161                                 "expected rc = 1; got rc = [%d]. "
2162                                 "key_rec->enc_key_size = [%d]\n", rc,
2163                                 key_rec->enc_key_size);
2164                 rc = -ENOMEM;
2165                 goto out;
2166         }
2167         mutex_lock(tfm_mutex);
2168         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2169                                      crypt_stat->key_size);
2170         if (rc < 0) {
2171                 mutex_unlock(tfm_mutex);
2172                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2173                                 "context; rc = [%d]\n", rc);
2174                 goto out;
2175         }
2176         rc = 0;
2177         ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes of the key\n",
2178                         crypt_stat->key_size);
2179         rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2180                                       (*key_rec).enc_key_size);
2181         mutex_unlock(tfm_mutex);
2182         if (rc) {
2183                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2184                 goto out;
2185         }
2186         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2187         if (ecryptfs_verbosity > 0) {
2188                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%d]:\n",
2189                                 key_rec->enc_key_size);
2190                 ecryptfs_dump_hex(key_rec->enc_key,
2191                                   key_rec->enc_key_size);
2192         }
2193 encrypted_session_key_set:
2194         /* This format is inspired by OpenPGP; see RFC 2440
2195          * packet tag 3 */
2196         max_packet_size = (1                         /* Tag 3 identifier */
2197                            + 3                       /* Max Tag 3 packet size */
2198                            + 1                       /* Version */
2199                            + 1                       /* Cipher code */
2200                            + 1                       /* S2K specifier */
2201                            + 1                       /* Hash identifier */
2202                            + ECRYPTFS_SALT_SIZE      /* Salt */
2203                            + 1                       /* Hash iterations */
2204                            + key_rec->enc_key_size); /* Encrypted key size */
2205         if (max_packet_size > (*remaining_bytes)) {
2206                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2207                        "there are only [%td] available\n", max_packet_size,
2208                        (*remaining_bytes));
2209                 rc = -EINVAL;
2210                 goto out;
2211         }
2212         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2213         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2214          * to get the number of octets in the actual Tag 3 packet */
2215         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2216                                           (max_packet_size - 4),
2217                                           &packet_size_length);
2218         if (rc) {
2219                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2220                        "generate packet length. rc = [%d]\n", rc);
2221                 goto out;
2222         }
2223         (*packet_size) += packet_size_length;
2224         dest[(*packet_size)++] = 0x04; /* version 4 */
2225         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2226          * specified with strings */
2227         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2228                                                       crypt_stat->key_size);
2229         if (cipher_code == 0) {
2230                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2231                                 "cipher [%s]\n", crypt_stat->cipher);
2232                 rc = -EINVAL;
2233                 goto out;
2234         }
2235         dest[(*packet_size)++] = cipher_code;
2236         dest[(*packet_size)++] = 0x03;  /* S2K */
2237         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2238         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2239                ECRYPTFS_SALT_SIZE);
2240         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2241         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2242         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2243                key_rec->enc_key_size);
2244         (*packet_size) += key_rec->enc_key_size;
2245 out:
2246         if (rc)
2247                 (*packet_size) = 0;
2248         else
2249                 (*remaining_bytes) -= (*packet_size);
2250         return rc;
2251 }
2252
2253 struct kmem_cache *ecryptfs_key_record_cache;
2254
2255 /**
2256  * ecryptfs_generate_key_packet_set
2257  * @dest_base: Virtual address from which to write the key record set
2258  * @crypt_stat: The cryptographic context from which the
2259  *              authentication tokens will be retrieved
2260  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2261  *                   for the global parameters
2262  * @len: The amount written
2263  * @max: The maximum amount of data allowed to be written
2264  *
2265  * Generates a key packet set and writes it to the virtual address
2266  * passed in.
2267  *
2268  * Returns zero on success; non-zero on error.
2269  */
2270 int
2271 ecryptfs_generate_key_packet_set(char *dest_base,
2272                                  struct ecryptfs_crypt_stat *crypt_stat,
2273                                  struct dentry *ecryptfs_dentry, size_t *len,
2274                                  size_t max)
2275 {
2276         struct ecryptfs_auth_tok *auth_tok;
2277         struct ecryptfs_global_auth_tok *global_auth_tok;
2278         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2279                 &ecryptfs_superblock_to_private(
2280                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2281         size_t written;
2282         struct ecryptfs_key_record *key_rec;
2283         struct ecryptfs_key_sig *key_sig;
2284         int rc = 0;
2285
2286         (*len) = 0;
2287         mutex_lock(&crypt_stat->keysig_list_mutex);
2288         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2289         if (!key_rec) {
2290                 rc = -ENOMEM;
2291                 goto out;
2292         }
2293         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2294                             crypt_stat_list) {
2295                 memset(key_rec, 0, sizeof(*key_rec));
2296                 rc = ecryptfs_find_global_auth_tok_for_sig(&global_auth_tok,
2297                                                            mount_crypt_stat,
2298                                                            key_sig->keysig);
2299                 if (rc) {
2300                         printk(KERN_ERR "Error attempting to get the global "
2301                                "auth_tok; rc = [%d]\n", rc);
2302                         goto out_free;
2303                 }
2304                 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID) {
2305                         printk(KERN_WARNING
2306                                "Skipping invalid auth tok with sig = [%s]\n",
2307                                global_auth_tok->sig);
2308                         continue;
2309                 }
2310                 auth_tok = global_auth_tok->global_auth_tok;
2311                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2312                         rc = write_tag_3_packet((dest_base + (*len)),
2313                                                 &max, auth_tok,
2314                                                 crypt_stat, key_rec,
2315                                                 &written);
2316                         if (rc) {
2317                                 ecryptfs_printk(KERN_WARNING, "Error "
2318                                                 "writing tag 3 packet\n");
2319                                 goto out_free;
2320                         }
2321                         (*len) += written;
2322                         /* Write auth tok signature packet */
2323                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2324                                                  key_rec->sig,
2325                                                  ECRYPTFS_SIG_SIZE, &written);
2326                         if (rc) {
2327                                 ecryptfs_printk(KERN_ERR, "Error writing "
2328                                                 "auth tok signature packet\n");
2329                                 goto out_free;
2330                         }
2331                         (*len) += written;
2332                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2333                         rc = write_tag_1_packet(dest_base + (*len),
2334                                                 &max, auth_tok,
2335                                                 crypt_stat, key_rec, &written);
2336                         if (rc) {
2337                                 ecryptfs_printk(KERN_WARNING, "Error "
2338                                                 "writing tag 1 packet\n");
2339                                 goto out_free;
2340                         }
2341                         (*len) += written;
2342                 } else {
2343                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2344                                         "authentication token type\n");
2345                         rc = -EINVAL;
2346                         goto out_free;
2347                 }
2348         }
2349         if (likely(max > 0)) {
2350                 dest_base[(*len)] = 0x00;
2351         } else {
2352                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2353                 rc = -EIO;
2354         }
2355 out_free:
2356         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2357 out:
2358         if (rc)
2359                 (*len) = 0;
2360         mutex_unlock(&crypt_stat->keysig_list_mutex);
2361         return rc;
2362 }
2363
2364 struct kmem_cache *ecryptfs_key_sig_cache;
2365
2366 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2367 {
2368         struct ecryptfs_key_sig *new_key_sig;
2369         int rc = 0;
2370
2371         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2372         if (!new_key_sig) {
2373                 rc = -ENOMEM;
2374                 printk(KERN_ERR
2375                        "Error allocating from ecryptfs_key_sig_cache\n");
2376                 goto out;
2377         }
2378         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2379         mutex_lock(&crypt_stat->keysig_list_mutex);
2380         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2381         mutex_unlock(&crypt_stat->keysig_list_mutex);
2382 out:
2383         return rc;
2384 }
2385
2386 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2387
2388 int
2389 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2390                              char *sig, u32 global_auth_tok_flags)
2391 {
2392         struct ecryptfs_global_auth_tok *new_auth_tok;
2393         int rc = 0;
2394
2395         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2396                                         GFP_KERNEL);
2397         if (!new_auth_tok) {
2398                 rc = -ENOMEM;
2399                 printk(KERN_ERR "Error allocating from "
2400                        "ecryptfs_global_auth_tok_cache\n");
2401                 goto out;
2402         }
2403         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2404         new_auth_tok->flags = global_auth_tok_flags;
2405         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2406         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2407         list_add(&new_auth_tok->mount_crypt_stat_list,
2408                  &mount_crypt_stat->global_auth_tok_list);
2409         mount_crypt_stat->num_global_auth_toks++;
2410         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2411 out:
2412         return rc;
2413 }
2414