linux/fs/ecryptfs/main.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * eCryptfs: Linux filesystem encryption layer
   4 *
   5 * Copyright (C) 1997-2003 Erez Zadok
   6 * Copyright (C) 2001-2003 Stony Brook University
   7 * Copyright (C) 2004-2007 International Business Machines Corp.
   8 *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
   9 *              Michael C. Thompson <mcthomps@us.ibm.com>
  10 *              Tyler Hicks <code@tyhicks.com>
  11 */
  12
  13#include <linux/dcache.h>
  14#include <linux/file.h>
  15#include <linux/module.h>
  16#include <linux/namei.h>
  17#include <linux/skbuff.h>
  18#include <linux/mount.h>
  19#include <linux/pagemap.h>
  20#include <linux/key.h>
  21#include <linux/parser.h>
  22#include <linux/fs_stack.h>
  23#include <linux/slab.h>
  24#include <linux/magic.h>
  25#include "ecryptfs_kernel.h"
  26
  27/*
  28 * Module parameter that defines the ecryptfs_verbosity level.
  29 */
  30int ecryptfs_verbosity = 0;
  31
  32module_param(ecryptfs_verbosity, int, 0);
  33MODULE_PARM_DESC(ecryptfs_verbosity,
  34                 "Initial verbosity level (0 or 1; defaults to "
  35                 "0, which is Quiet)");
  36
  37/*
  38 * Module parameter that defines the number of message buffer elements
  39 */
  40unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
  41
  42module_param(ecryptfs_message_buf_len, uint, 0);
  43MODULE_PARM_DESC(ecryptfs_message_buf_len,
  44                 "Number of message buffer elements");
  45
  46/*
  47 * Module parameter that defines the maximum guaranteed amount of time to wait
  48 * for a response from ecryptfsd.  The actual sleep time will be, more than
  49 * likely, a small amount greater than this specified value, but only less if
  50 * the message successfully arrives.
  51 */
  52signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
  53
  54module_param(ecryptfs_message_wait_timeout, long, 0);
  55MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
  56                 "Maximum number of seconds that an operation will "
  57                 "sleep while waiting for a message response from "
  58                 "userspace");
  59
  60/*
  61 * Module parameter that is an estimate of the maximum number of users
  62 * that will be concurrently using eCryptfs. Set this to the right
  63 * value to balance performance and memory use.
  64 */
  65unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
  66
  67module_param(ecryptfs_number_of_users, uint, 0);
  68MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
  69                 "concurrent users of eCryptfs");
  70
  71void __ecryptfs_printk(const char *fmt, ...)
  72{
  73        va_list args;
  74        va_start(args, fmt);
  75        if (fmt[1] == '7') { /* KERN_DEBUG */
  76                if (ecryptfs_verbosity >= 1)
  77                        vprintk(fmt, args);
  78        } else
  79                vprintk(fmt, args);
  80        va_end(args);
  81}
  82
  83/*
  84 * ecryptfs_init_lower_file
  85 * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
  86 *                   the lower dentry and the lower mount set
  87 *
  88 * eCryptfs only ever keeps a single open file for every lower
  89 * inode. All I/O operations to the lower inode occur through that
  90 * file. When the first eCryptfs dentry that interposes with the first
  91 * lower dentry for that inode is created, this function creates the
  92 * lower file struct and associates it with the eCryptfs
  93 * inode. When all eCryptfs files associated with the inode are released, the
  94 * file is closed.
  95 *
  96 * The lower file will be opened with read/write permissions, if
  97 * possible. Otherwise, it is opened read-only.
  98 *
  99 * This function does nothing if a lower file is already
 100 * associated with the eCryptfs inode.
 101 *
 102 * Returns zero on success; non-zero otherwise
 103 */
 104static int ecryptfs_init_lower_file(struct dentry *dentry,
 105                                    struct file **lower_file)
 106{
 107        const struct cred *cred = current_cred();
 108        struct path *path = ecryptfs_dentry_to_lower_path(dentry);
 109        int rc;
 110
 111        rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
 112                                      cred);
 113        if (rc) {
 114                printk(KERN_ERR "Error opening lower file "
 115                       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
 116                       "rc = [%d]\n", path->dentry, path->mnt, rc);
 117                (*lower_file) = NULL;
 118        }
 119        return rc;
 120}
 121
 122int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
 123{
 124        struct ecryptfs_inode_info *inode_info;
 125        int count, rc = 0;
 126
 127        inode_info = ecryptfs_inode_to_private(inode);
 128        mutex_lock(&inode_info->lower_file_mutex);
 129        count = atomic_inc_return(&inode_info->lower_file_count);
 130        if (WARN_ON_ONCE(count < 1))
 131                rc = -EINVAL;
 132        else if (count == 1) {
 133                rc = ecryptfs_init_lower_file(dentry,
 134                                              &inode_info->lower_file);
 135                if (rc)
 136                        atomic_set(&inode_info->lower_file_count, 0);
 137        }
 138        mutex_unlock(&inode_info->lower_file_mutex);
 139        return rc;
 140}
 141
 142void ecryptfs_put_lower_file(struct inode *inode)
 143{
 144        struct ecryptfs_inode_info *inode_info;
 145
 146        inode_info = ecryptfs_inode_to_private(inode);
 147        if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
 148                                      &inode_info->lower_file_mutex)) {
 149                filemap_write_and_wait(inode->i_mapping);
 150                fput(inode_info->lower_file);
 151                inode_info->lower_file = NULL;
 152                mutex_unlock(&inode_info->lower_file_mutex);
 153        }
 154}
 155
 156enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
 157       ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
 158       ecryptfs_opt_ecryptfs_key_bytes,
 159       ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
 160       ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
 161       ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
 162       ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
 163       ecryptfs_opt_check_dev_ruid,
 164       ecryptfs_opt_err };
 165
 166static const match_table_t tokens = {
 167        {ecryptfs_opt_sig, "sig=%s"},
 168        {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 169        {ecryptfs_opt_cipher, "cipher=%s"},
 170        {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
 171        {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
 172        {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
 173        {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
 174        {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
 175        {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
 176        {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
 177        {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
 178        {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
 179        {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
 180        {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
 181        {ecryptfs_opt_err, NULL}
 182};
 183
 184static int ecryptfs_init_global_auth_toks(
 185        struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 186{
 187        struct ecryptfs_global_auth_tok *global_auth_tok;
 188        struct ecryptfs_auth_tok *auth_tok;
 189        int rc = 0;
 190
 191        list_for_each_entry(global_auth_tok,
 192                            &mount_crypt_stat->global_auth_tok_list,
 193                            mount_crypt_stat_list) {
 194                rc = ecryptfs_keyring_auth_tok_for_sig(
 195                        &global_auth_tok->global_auth_tok_key, &auth_tok,
 196                        global_auth_tok->sig);
 197                if (rc) {
 198                        printk(KERN_ERR "Could not find valid key in user "
 199                               "session keyring for sig specified in mount "
 200                               "option: [%s]\n", global_auth_tok->sig);
 201                        global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
 202                        goto out;
 203                } else {
 204                        global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
 205                        up_write(&(global_auth_tok->global_auth_tok_key)->sem);
 206                }
 207        }
 208out:
 209        return rc;
 210}
 211
 212static void ecryptfs_init_mount_crypt_stat(
 213        struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 214{
 215        memset((void *)mount_crypt_stat, 0,
 216               sizeof(struct ecryptfs_mount_crypt_stat));
 217        INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
 218        mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
 219        mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
 220}
 221
 222/**
 223 * ecryptfs_parse_options
 224 * @sbi: The ecryptfs super block
 225 * @options: The options passed to the kernel
 226 * @check_ruid: set to 1 if device uid should be checked against the ruid
 227 *
 228 * Parse mount options:
 229 * debug=N         - ecryptfs_verbosity level for debug output
 230 * sig=XXX         - description(signature) of the key to use
 231 *
 232 * Returns the dentry object of the lower-level (lower/interposed)
 233 * directory; We want to mount our stackable file system on top of
 234 * that lower directory.
 235 *
 236 * The signature of the key to use must be the description of a key
 237 * already in the keyring. Mounting will fail if the key can not be
 238 * found.
 239 *
 240 * Returns zero on success; non-zero on error
 241 */
 242static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
 243                                  uid_t *check_ruid)
 244{
 245        char *p;
 246        int rc = 0;
 247        int sig_set = 0;
 248        int cipher_name_set = 0;
 249        int fn_cipher_name_set = 0;
 250        int cipher_key_bytes;
 251        int cipher_key_bytes_set = 0;
 252        int fn_cipher_key_bytes;
 253        int fn_cipher_key_bytes_set = 0;
 254        struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 255                &sbi->mount_crypt_stat;
 256        substring_t args[MAX_OPT_ARGS];
 257        int token;
 258        char *sig_src;
 259        char *cipher_name_dst;
 260        char *cipher_name_src;
 261        char *fn_cipher_name_dst;
 262        char *fn_cipher_name_src;
 263        char *fnek_dst;
 264        char *fnek_src;
 265        char *cipher_key_bytes_src;
 266        char *fn_cipher_key_bytes_src;
 267        u8 cipher_code;
 268
 269        *check_ruid = 0;
 270
 271        if (!options) {
 272                rc = -EINVAL;
 273                goto out;
 274        }
 275        ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
 276        while ((p = strsep(&options, ",")) != NULL) {
 277                if (!*p)
 278                        continue;
 279                token = match_token(p, tokens, args);
 280                switch (token) {
 281                case ecryptfs_opt_sig:
 282                case ecryptfs_opt_ecryptfs_sig:
 283                        sig_src = args[0].from;
 284                        rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
 285                                                          sig_src, 0);
 286                        if (rc) {
 287                                printk(KERN_ERR "Error attempting to register "
 288                                       "global sig; rc = [%d]\n", rc);
 289                                goto out;
 290                        }
 291                        sig_set = 1;
 292                        break;
 293                case ecryptfs_opt_cipher:
 294                case ecryptfs_opt_ecryptfs_cipher:
 295                        cipher_name_src = args[0].from;
 296                        cipher_name_dst =
 297                                mount_crypt_stat->
 298                                global_default_cipher_name;
 299                        strncpy(cipher_name_dst, cipher_name_src,
 300                                ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 301                        cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 302                        cipher_name_set = 1;
 303                        break;
 304                case ecryptfs_opt_ecryptfs_key_bytes:
 305                        cipher_key_bytes_src = args[0].from;
 306                        cipher_key_bytes =
 307                                (int)simple_strtol(cipher_key_bytes_src,
 308                                                   &cipher_key_bytes_src, 0);
 309                        mount_crypt_stat->global_default_cipher_key_size =
 310                                cipher_key_bytes;
 311                        cipher_key_bytes_set = 1;
 312                        break;
 313                case ecryptfs_opt_passthrough:
 314                        mount_crypt_stat->flags |=
 315                                ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
 316                        break;
 317                case ecryptfs_opt_xattr_metadata:
 318                        mount_crypt_stat->flags |=
 319                                ECRYPTFS_XATTR_METADATA_ENABLED;
 320                        break;
 321                case ecryptfs_opt_encrypted_view:
 322                        mount_crypt_stat->flags |=
 323                                ECRYPTFS_XATTR_METADATA_ENABLED;
 324                        mount_crypt_stat->flags |=
 325                                ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
 326                        break;
 327                case ecryptfs_opt_fnek_sig:
 328                        fnek_src = args[0].from;
 329                        fnek_dst =
 330                                mount_crypt_stat->global_default_fnek_sig;
 331                        strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
 332                        mount_crypt_stat->global_default_fnek_sig[
 333                                ECRYPTFS_SIG_SIZE_HEX] = '\0';
 334                        rc = ecryptfs_add_global_auth_tok(
 335                                mount_crypt_stat,
 336                                mount_crypt_stat->global_default_fnek_sig,
 337                                ECRYPTFS_AUTH_TOK_FNEK);
 338                        if (rc) {
 339                                printk(KERN_ERR "Error attempting to register "
 340                                       "global fnek sig [%s]; rc = [%d]\n",
 341                                       mount_crypt_stat->global_default_fnek_sig,
 342                                       rc);
 343                                goto out;
 344                        }
 345                        mount_crypt_stat->flags |=
 346                                (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
 347                                 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
 348                        break;
 349                case ecryptfs_opt_fn_cipher:
 350                        fn_cipher_name_src = args[0].from;
 351                        fn_cipher_name_dst =
 352                                mount_crypt_stat->global_default_fn_cipher_name;
 353                        strncpy(fn_cipher_name_dst, fn_cipher_name_src,
 354                                ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 355                        mount_crypt_stat->global_default_fn_cipher_name[
 356                                ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
 357                        fn_cipher_name_set = 1;
 358                        break;
 359                case ecryptfs_opt_fn_cipher_key_bytes:
 360                        fn_cipher_key_bytes_src = args[0].from;
 361                        fn_cipher_key_bytes =
 362                                (int)simple_strtol(fn_cipher_key_bytes_src,
 363                                                   &fn_cipher_key_bytes_src, 0);
 364                        mount_crypt_stat->global_default_fn_cipher_key_bytes =
 365                                fn_cipher_key_bytes;
 366                        fn_cipher_key_bytes_set = 1;
 367                        break;
 368                case ecryptfs_opt_unlink_sigs:
 369                        mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
 370                        break;
 371                case ecryptfs_opt_mount_auth_tok_only:
 372                        mount_crypt_stat->flags |=
 373                                ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
 374                        break;
 375                case ecryptfs_opt_check_dev_ruid:
 376                        *check_ruid = 1;
 377                        break;
 378                case ecryptfs_opt_err:
 379                default:
 380                        printk(KERN_WARNING
 381                               "%s: eCryptfs: unrecognized option [%s]\n",
 382                               __func__, p);
 383                }
 384        }
 385        if (!sig_set) {
 386                rc = -EINVAL;
 387                ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
 388                                "auth tok signature as a mount "
 389                                "parameter; see the eCryptfs README\n");
 390                goto out;
 391        }
 392        if (!cipher_name_set) {
 393                int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
 394
 395                BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
 396                strcpy(mount_crypt_stat->global_default_cipher_name,
 397                       ECRYPTFS_DEFAULT_CIPHER);
 398        }
 399        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 400            && !fn_cipher_name_set)
 401                strcpy(mount_crypt_stat->global_default_fn_cipher_name,
 402                       mount_crypt_stat->global_default_cipher_name);
 403        if (!cipher_key_bytes_set)
 404                mount_crypt_stat->global_default_cipher_key_size = 0;
 405        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 406            && !fn_cipher_key_bytes_set)
 407                mount_crypt_stat->global_default_fn_cipher_key_bytes =
 408                        mount_crypt_stat->global_default_cipher_key_size;
 409
 410        cipher_code = ecryptfs_code_for_cipher_string(
 411                mount_crypt_stat->global_default_cipher_name,
 412                mount_crypt_stat->global_default_cipher_key_size);
 413        if (!cipher_code) {
 414                ecryptfs_printk(KERN_ERR,
 415                                "eCryptfs doesn't support cipher: %s\n",
 416                                mount_crypt_stat->global_default_cipher_name);
 417                rc = -EINVAL;
 418                goto out;
 419        }
 420
 421        mutex_lock(&key_tfm_list_mutex);
 422        if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
 423                                 NULL)) {
 424                rc = ecryptfs_add_new_key_tfm(
 425                        NULL, mount_crypt_stat->global_default_cipher_name,
 426                        mount_crypt_stat->global_default_cipher_key_size);
 427                if (rc) {
 428                        printk(KERN_ERR "Error attempting to initialize "
 429                               "cipher with name = [%s] and key size = [%td]; "
 430                               "rc = [%d]\n",
 431                               mount_crypt_stat->global_default_cipher_name,
 432                               mount_crypt_stat->global_default_cipher_key_size,
 433                               rc);
 434                        rc = -EINVAL;
 435                        mutex_unlock(&key_tfm_list_mutex);
 436                        goto out;
 437                }
 438        }
 439        if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
 440            && !ecryptfs_tfm_exists(
 441                    mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
 442                rc = ecryptfs_add_new_key_tfm(
 443                        NULL, mount_crypt_stat->global_default_fn_cipher_name,
 444                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
 445                if (rc) {
 446                        printk(KERN_ERR "Error attempting to initialize "
 447                               "cipher with name = [%s] and key size = [%td]; "
 448                               "rc = [%d]\n",
 449                               mount_crypt_stat->global_default_fn_cipher_name,
 450                               mount_crypt_stat->global_default_fn_cipher_key_bytes,
 451                               rc);
 452                        rc = -EINVAL;
 453                        mutex_unlock(&key_tfm_list_mutex);
 454                        goto out;
 455                }
 456        }
 457        mutex_unlock(&key_tfm_list_mutex);
 458        rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
 459        if (rc)
 460                printk(KERN_WARNING "One or more global auth toks could not "
 461                       "properly register; rc = [%d]\n", rc);
 462out:
 463        return rc;
 464}
 465
 466struct kmem_cache *ecryptfs_sb_info_cache;
 467static struct file_system_type ecryptfs_fs_type;
 468
 469/*
 470 * ecryptfs_mount
 471 * @fs_type: The filesystem type that the superblock should belong to
 472 * @flags: The flags associated with the mount
 473 * @dev_name: The path to mount over
 474 * @raw_data: The options passed into the kernel
 475 */
 476static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
 477                        const char *dev_name, void *raw_data)
 478{
 479        struct super_block *s;
 480        struct ecryptfs_sb_info *sbi;
 481        struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 482        struct ecryptfs_dentry_info *root_info;
 483        const char *err = "Getting sb failed";
 484        struct inode *inode;
 485        struct path path;
 486        uid_t check_ruid;
 487        int rc;
 488
 489        sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
 490        if (!sbi) {
 491                rc = -ENOMEM;
 492                goto out;
 493        }
 494
 495        if (!dev_name) {
 496                rc = -EINVAL;
 497                err = "Device name cannot be null";
 498                goto out;
 499        }
 500
 501        rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
 502        if (rc) {
 503                err = "Error parsing options";
 504                goto out;
 505        }
 506        mount_crypt_stat = &sbi->mount_crypt_stat;
 507
 508        s = sget(fs_type, NULL, set_anon_super, flags, NULL);
 509        if (IS_ERR(s)) {
 510                rc = PTR_ERR(s);
 511                goto out;
 512        }
 513
 514        rc = super_setup_bdi(s);
 515        if (rc)
 516                goto out1;
 517
 518        ecryptfs_set_superblock_private(s, sbi);
 519
 520        /* ->kill_sb() will take care of sbi after that point */
 521        sbi = NULL;
 522        s->s_op = &ecryptfs_sops;
 523        s->s_xattr = ecryptfs_xattr_handlers;
 524        s->s_d_op = &ecryptfs_dops;
 525
 526        err = "Reading sb failed";
 527        rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
 528        if (rc) {
 529                ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
 530                goto out1;
 531        }
 532        if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
 533                rc = -EINVAL;
 534                printk(KERN_ERR "Mount on filesystem of type "
 535                        "eCryptfs explicitly disallowed due to "
 536                        "known incompatibilities\n");
 537                goto out_free;
 538        }
 539
 540        if (mnt_user_ns(path.mnt) != &init_user_ns) {
 541                rc = -EINVAL;
 542                printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
 543                goto out_free;
 544        }
 545
 546        if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
 547                rc = -EPERM;
 548                printk(KERN_ERR "Mount of device (uid: %d) not owned by "
 549                       "requested user (uid: %d)\n",
 550                        i_uid_read(d_inode(path.dentry)),
 551                        from_kuid(&init_user_ns, current_uid()));
 552                goto out_free;
 553        }
 554
 555        ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
 556
 557        /**
 558         * Set the POSIX ACL flag based on whether they're enabled in the lower
 559         * mount.
 560         */
 561        s->s_flags = flags & ~SB_POSIXACL;
 562        s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
 563
 564        /**
 565         * Force a read-only eCryptfs mount when:
 566         *   1) The lower mount is ro
 567         *   2) The ecryptfs_encrypted_view mount option is specified
 568         */
 569        if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 570                s->s_flags |= SB_RDONLY;
 571
 572        s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
 573        s->s_blocksize = path.dentry->d_sb->s_blocksize;
 574        s->s_magic = ECRYPTFS_SUPER_MAGIC;
 575        s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
 576
 577        rc = -EINVAL;
 578        if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
 579                pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
 580                goto out_free;
 581        }
 582
 583        inode = ecryptfs_get_inode(d_inode(path.dentry), s);
 584        rc = PTR_ERR(inode);
 585        if (IS_ERR(inode))
 586                goto out_free;
 587
 588        s->s_root = d_make_root(inode);
 589        if (!s->s_root) {
 590                rc = -ENOMEM;
 591                goto out_free;
 592        }
 593
 594        rc = -ENOMEM;
 595        root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
 596        if (!root_info)
 597                goto out_free;
 598
 599        /* ->kill_sb() will take care of root_info */
 600        ecryptfs_set_dentry_private(s->s_root, root_info);
 601        root_info->lower_path = path;
 602
 603        s->s_flags |= SB_ACTIVE;
 604        return dget(s->s_root);
 605
 606out_free:
 607        path_put(&path);
 608out1:
 609        deactivate_locked_super(s);
 610out:
 611        if (sbi) {
 612                ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
 613                kmem_cache_free(ecryptfs_sb_info_cache, sbi);
 614        }
 615        printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
 616        return ERR_PTR(rc);
 617}
 618
 619/**
 620 * ecryptfs_kill_block_super
 621 * @sb: The ecryptfs super block
 622 *
 623 * Used to bring the superblock down and free the private data.
 624 */
 625static void ecryptfs_kill_block_super(struct super_block *sb)
 626{
 627        struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
 628        kill_anon_super(sb);
 629        if (!sb_info)
 630                return;
 631        ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
 632        kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 633}
 634
 635static struct file_system_type ecryptfs_fs_type = {
 636        .owner = THIS_MODULE,
 637        .name = "ecryptfs",
 638        .mount = ecryptfs_mount,
 639        .kill_sb = ecryptfs_kill_block_super,
 640        .fs_flags = 0
 641};
 642MODULE_ALIAS_FS("ecryptfs");
 643
 644/*
 645 * inode_info_init_once
 646 *
 647 * Initializes the ecryptfs_inode_info_cache when it is created
 648 */
 649static void
 650inode_info_init_once(void *vptr)
 651{
 652        struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
 653
 654        inode_init_once(&ei->vfs_inode);
 655}
 656
 657static struct ecryptfs_cache_info {
 658        struct kmem_cache **cache;
 659        const char *name;
 660        size_t size;
 661        slab_flags_t flags;
 662        void (*ctor)(void *obj);
 663} ecryptfs_cache_infos[] = {
 664        {
 665                .cache = &ecryptfs_auth_tok_list_item_cache,
 666                .name = "ecryptfs_auth_tok_list_item",
 667                .size = sizeof(struct ecryptfs_auth_tok_list_item),
 668        },
 669        {
 670                .cache = &ecryptfs_file_info_cache,
 671                .name = "ecryptfs_file_cache",
 672                .size = sizeof(struct ecryptfs_file_info),
 673        },
 674        {
 675                .cache = &ecryptfs_dentry_info_cache,
 676                .name = "ecryptfs_dentry_info_cache",
 677                .size = sizeof(struct ecryptfs_dentry_info),
 678        },
 679        {
 680                .cache = &ecryptfs_inode_info_cache,
 681                .name = "ecryptfs_inode_cache",
 682                .size = sizeof(struct ecryptfs_inode_info),
 683                .flags = SLAB_ACCOUNT,
 684                .ctor = inode_info_init_once,
 685        },
 686        {
 687                .cache = &ecryptfs_sb_info_cache,
 688                .name = "ecryptfs_sb_cache",
 689                .size = sizeof(struct ecryptfs_sb_info),
 690        },
 691        {
 692                .cache = &ecryptfs_header_cache,
 693                .name = "ecryptfs_headers",
 694                .size = PAGE_SIZE,
 695        },
 696        {
 697                .cache = &ecryptfs_xattr_cache,
 698                .name = "ecryptfs_xattr_cache",
 699                .size = PAGE_SIZE,
 700        },
 701        {
 702                .cache = &ecryptfs_key_record_cache,
 703                .name = "ecryptfs_key_record_cache",
 704                .size = sizeof(struct ecryptfs_key_record),
 705        },
 706        {
 707                .cache = &ecryptfs_key_sig_cache,
 708                .name = "ecryptfs_key_sig_cache",
 709                .size = sizeof(struct ecryptfs_key_sig),
 710        },
 711        {
 712                .cache = &ecryptfs_global_auth_tok_cache,
 713                .name = "ecryptfs_global_auth_tok_cache",
 714                .size = sizeof(struct ecryptfs_global_auth_tok),
 715        },
 716        {
 717                .cache = &ecryptfs_key_tfm_cache,
 718                .name = "ecryptfs_key_tfm_cache",
 719                .size = sizeof(struct ecryptfs_key_tfm),
 720        },
 721};
 722
 723static void ecryptfs_free_kmem_caches(void)
 724{
 725        int i;
 726
 727        /*
 728         * Make sure all delayed rcu free inodes are flushed before we
 729         * destroy cache.
 730         */
 731        rcu_barrier();
 732
 733        for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 734                struct ecryptfs_cache_info *info;
 735
 736                info = &ecryptfs_cache_infos[i];
 737                kmem_cache_destroy(*(info->cache));
 738        }
 739}
 740
 741/**
 742 * ecryptfs_init_kmem_caches
 743 *
 744 * Returns zero on success; non-zero otherwise
 745 */
 746static int ecryptfs_init_kmem_caches(void)
 747{
 748        int i;
 749
 750        for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
 751                struct ecryptfs_cache_info *info;
 752
 753                info = &ecryptfs_cache_infos[i];
 754                *(info->cache) = kmem_cache_create(info->name, info->size, 0,
 755                                SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
 756                if (!*(info->cache)) {
 757                        ecryptfs_free_kmem_caches();
 758                        ecryptfs_printk(KERN_WARNING, "%s: "
 759                                        "kmem_cache_create failed\n",
 760                                        info->name);
 761                        return -ENOMEM;
 762                }
 763        }
 764        return 0;
 765}
 766
 767static struct kobject *ecryptfs_kobj;
 768
 769static ssize_t version_show(struct kobject *kobj,
 770                            struct kobj_attribute *attr, char *buff)
 771{
 772        return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
 773}
 774
 775static struct kobj_attribute version_attr = __ATTR_RO(version);
 776
 777static struct attribute *attributes[] = {
 778        &version_attr.attr,
 779        NULL,
 780};
 781
 782static const struct attribute_group attr_group = {
 783        .attrs = attributes,
 784};
 785
 786static int do_sysfs_registration(void)
 787{
 788        int rc;
 789
 790        ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
 791        if (!ecryptfs_kobj) {
 792                printk(KERN_ERR "Unable to create ecryptfs kset\n");
 793                rc = -ENOMEM;
 794                goto out;
 795        }
 796        rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
 797        if (rc) {
 798                printk(KERN_ERR
 799                       "Unable to create ecryptfs version attributes\n");
 800                kobject_put(ecryptfs_kobj);
 801        }
 802out:
 803        return rc;
 804}
 805
 806static void do_sysfs_unregistration(void)
 807{
 808        sysfs_remove_group(ecryptfs_kobj, &attr_group);
 809        kobject_put(ecryptfs_kobj);
 810}
 811
 812static int __init ecryptfs_init(void)
 813{
 814        int rc;
 815
 816        if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
 817                rc = -EINVAL;
 818                ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
 819                                "larger than the host's page size, and so "
 820                                "eCryptfs cannot run on this system. The "
 821                                "default eCryptfs extent size is [%u] bytes; "
 822                                "the page size is [%lu] bytes.\n",
 823                                ECRYPTFS_DEFAULT_EXTENT_SIZE,
 824                                (unsigned long)PAGE_SIZE);
 825                goto out;
 826        }
 827        rc = ecryptfs_init_kmem_caches();
 828        if (rc) {
 829                printk(KERN_ERR
 830                       "Failed to allocate one or more kmem_cache objects\n");
 831                goto out;
 832        }
 833        rc = do_sysfs_registration();
 834        if (rc) {
 835                printk(KERN_ERR "sysfs registration failed\n");
 836                goto out_free_kmem_caches;
 837        }
 838        rc = ecryptfs_init_kthread();
 839        if (rc) {
 840                printk(KERN_ERR "%s: kthread initialization failed; "
 841                       "rc = [%d]\n", __func__, rc);
 842                goto out_do_sysfs_unregistration;
 843        }
 844        rc = ecryptfs_init_messaging();
 845        if (rc) {
 846                printk(KERN_ERR "Failure occurred while attempting to "
 847                                "initialize the communications channel to "
 848                                "ecryptfsd\n");
 849                goto out_destroy_kthread;
 850        }
 851        rc = ecryptfs_init_crypto();
 852        if (rc) {
 853                printk(KERN_ERR "Failure whilst attempting to init crypto; "
 854                       "rc = [%d]\n", rc);
 855                goto out_release_messaging;
 856        }
 857        rc = register_filesystem(&ecryptfs_fs_type);
 858        if (rc) {
 859                printk(KERN_ERR "Failed to register filesystem\n");
 860                goto out_destroy_crypto;
 861        }
 862        if (ecryptfs_verbosity > 0)
 863                printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
 864                        "will be written to the syslog!\n", ecryptfs_verbosity);
 865
 866        goto out;
 867out_destroy_crypto:
 868        ecryptfs_destroy_crypto();
 869out_release_messaging:
 870        ecryptfs_release_messaging();
 871out_destroy_kthread:
 872        ecryptfs_destroy_kthread();
 873out_do_sysfs_unregistration:
 874        do_sysfs_unregistration();
 875out_free_kmem_caches:
 876        ecryptfs_free_kmem_caches();
 877out:
 878        return rc;
 879}
 880
 881static void __exit ecryptfs_exit(void)
 882{
 883        int rc;
 884
 885        rc = ecryptfs_destroy_crypto();
 886        if (rc)
 887                printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
 888                       "rc = [%d]\n", rc);
 889        ecryptfs_release_messaging();
 890        ecryptfs_destroy_kthread();
 891        do_sysfs_unregistration();
 892        unregister_filesystem(&ecryptfs_fs_type);
 893        ecryptfs_free_kmem_caches();
 894}
 895
 896MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
 897MODULE_DESCRIPTION("eCryptfs");
 898
 899MODULE_LICENSE("GPL");
 900
 901module_init(ecryptfs_init)
 902module_exit(ecryptfs_exit)
 903