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