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TOMOYO Linux Cross Reference
Linux/fs/ecryptfs/main.c

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  1 /**
  2  * eCryptfs: Linux filesystem encryption layer
  3  *
  4  * Copyright (C) 1997-2003 Erez Zadok
  5  * Copyright (C) 2001-2003 Stony Brook University
  6  * Copyright (C) 2004-2007 International Business Machines Corp.
  7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  8  *              Michael C. Thompson <mcthomps@us.ibm.com>
  9  *              Tyler Hicks <tyhicks@ou.edu>
 10  *
 11  * This program is free software; you can redistribute it and/or
 12  * modify it under the terms of the GNU General Public License as
 13  * published by the Free Software Foundation; either version 2 of the
 14  * License, or (at your option) any later version.
 15  *
 16  * This program is distributed in the hope that it will be useful, but
 17  * WITHOUT ANY WARRANTY; without even the implied warranty of
 18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 19  * General Public License for more details.
 20  *
 21  * You should have received a copy of the GNU General Public License
 22  * along with this program; if not, write to the Free Software
 23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 24  * 02111-1307, USA.
 25  */
 26 
 27 #include <linux/dcache.h>
 28 #include <linux/file.h>
 29 #include <linux/module.h>
 30 #include <linux/namei.h>
 31 #include <linux/skbuff.h>
 32 #include <linux/crypto.h>
 33 #include <linux/mount.h>
 34 #include <linux/pagemap.h>
 35 #include <linux/key.h>
 36 #include <linux/parser.h>
 37 #include <linux/fs_stack.h>
 38 #include <linux/slab.h>
 39 #include <linux/magic.h>
 40 #include "ecryptfs_kernel.h"
 41 
 42 /**
 43  * Module parameter that defines the ecryptfs_verbosity level.
 44  */
 45 int ecryptfs_verbosity = 0;
 46 
 47 module_param(ecryptfs_verbosity, int, 0);
 48 MODULE_PARM_DESC(ecryptfs_verbosity,
 49                  "Initial verbosity level (0 or 1; defaults to "
 50                  "0, which is Quiet)");
 51 
 52 /**
 53  * Module parameter that defines the number of message buffer elements
 54  */
 55 unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
 56 
 57 module_param(ecryptfs_message_buf_len, uint, 0);
 58 MODULE_PARM_DESC(ecryptfs_message_buf_len,
 59                  "Number of message buffer elements");
 60 
 61 /**
 62  * Module parameter that defines the maximum guaranteed amount of time to wait
 63  * for a response from ecryptfsd.  The actual sleep time will be, more than
 64  * likely, a small amount greater than this specified value, but only less if
 65  * the message successfully arrives.
 66  */
 67 signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
 68 
 69 module_param(ecryptfs_message_wait_timeout, long, 0);
 70 MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
 71                  "Maximum number of seconds that an operation will "
 72                  "sleep while waiting for a message response from "
 73                  "userspace");
 74 
 75 /**
 76  * Module parameter that is an estimate of the maximum number of users
 77  * that will be concurrently using eCryptfs. Set this to the right
 78  * value to balance performance and memory use.
 79  */
 80 unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
 81 
 82 module_param(ecryptfs_number_of_users, uint, 0);
 83 MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
 84                  "concurrent users of eCryptfs");
 85 
 86 void __ecryptfs_printk(const char *fmt, ...)
 87 {
 88         va_list args;
 89         va_start(args, fmt);
 90         if (fmt[1] == '7') { /* KERN_DEBUG */
 91                 if (ecryptfs_verbosity >= 1)
 92                         vprintk(fmt, args);
 93         } else
 94                 vprintk(fmt, args);
 95         va_end(args);
 96 }
 97 
 98 /**
 99  * ecryptfs_init_lower_file
100  * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
101  *                   the lower dentry and the lower mount set
102  *
103  * eCryptfs only ever keeps a single open file for every lower
104  * inode. All I/O operations to the lower inode occur through that
105  * file. When the first eCryptfs dentry that interposes with the first
106  * lower dentry for that inode is created, this function creates the
107  * lower file struct and associates it with the eCryptfs
108  * inode. When all eCryptfs files associated with the inode are released, the
109  * file is closed.
110  *
111  * The lower file will be opened with read/write permissions, if
112  * possible. Otherwise, it is opened read-only.
113  *
114  * This function does nothing if a lower file is already
115  * associated with the eCryptfs inode.
116  *
117  * Returns zero on success; non-zero otherwise
118  */
119 static int ecryptfs_init_lower_file(struct dentry *dentry,
120                                     struct file **lower_file)
121 {
122         const struct cred *cred = current_cred();
123         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
124         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
125         int rc;
126 
127         rc = ecryptfs_privileged_open(lower_file, lower_dentry, lower_mnt,
128                                       cred);
129         if (rc) {
130                 printk(KERN_ERR "Error opening lower file "
131                        "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
132                        "rc = [%d]\n", lower_dentry, lower_mnt, rc);
133                 (*lower_file) = NULL;
134         }
135         return rc;
136 }
137 
138 int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
139 {
140         struct ecryptfs_inode_info *inode_info;
141         int count, rc = 0;
142 
143         inode_info = ecryptfs_inode_to_private(inode);
144         mutex_lock(&inode_info->lower_file_mutex);
145         count = atomic_inc_return(&inode_info->lower_file_count);
146         if (WARN_ON_ONCE(count < 1))
147                 rc = -EINVAL;
148         else if (count == 1) {
149                 rc = ecryptfs_init_lower_file(dentry,
150                                               &inode_info->lower_file);
151                 if (rc)
152                         atomic_set(&inode_info->lower_file_count, 0);
153         }
154         mutex_unlock(&inode_info->lower_file_mutex);
155         return rc;
156 }
157 
158 void ecryptfs_put_lower_file(struct inode *inode)
159 {
160         struct ecryptfs_inode_info *inode_info;
161 
162         inode_info = ecryptfs_inode_to_private(inode);
163         if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
164                                       &inode_info->lower_file_mutex)) {
165                 filemap_write_and_wait(inode->i_mapping);
166                 fput(inode_info->lower_file);
167                 inode_info->lower_file = NULL;
168                 mutex_unlock(&inode_info->lower_file_mutex);
169         }
170 }
171 
172 enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
173        ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
174        ecryptfs_opt_ecryptfs_key_bytes,
175        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
176        ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
177        ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
178        ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
179        ecryptfs_opt_check_dev_ruid,
180        ecryptfs_opt_err };
181 
182 static const match_table_t tokens = {
183         {ecryptfs_opt_sig, "sig=%s"},
184         {ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
185         {ecryptfs_opt_cipher, "cipher=%s"},
186         {ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
187         {ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
188         {ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
189         {ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
190         {ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
191         {ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
192         {ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
193         {ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
194         {ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
195         {ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
196         {ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
197         {ecryptfs_opt_err, NULL}
198 };
199 
200 static int ecryptfs_init_global_auth_toks(
201         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
202 {
203         struct ecryptfs_global_auth_tok *global_auth_tok;
204         struct ecryptfs_auth_tok *auth_tok;
205         int rc = 0;
206 
207         list_for_each_entry(global_auth_tok,
208                             &mount_crypt_stat->global_auth_tok_list,
209                             mount_crypt_stat_list) {
210                 rc = ecryptfs_keyring_auth_tok_for_sig(
211                         &global_auth_tok->global_auth_tok_key, &auth_tok,
212                         global_auth_tok->sig);
213                 if (rc) {
214                         printk(KERN_ERR "Could not find valid key in user "
215                                "session keyring for sig specified in mount "
216                                "option: [%s]\n", global_auth_tok->sig);
217                         global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
218                         goto out;
219                 } else {
220                         global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
221                         up_write(&(global_auth_tok->global_auth_tok_key)->sem);
222                 }
223         }
224 out:
225         return rc;
226 }
227 
228 static void ecryptfs_init_mount_crypt_stat(
229         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
230 {
231         memset((void *)mount_crypt_stat, 0,
232                sizeof(struct ecryptfs_mount_crypt_stat));
233         INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
234         mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
235         mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
236 }
237 
238 /**
239  * ecryptfs_parse_options
240  * @sb: The ecryptfs super block
241  * @options: The options passed to the kernel
242  * @check_ruid: set to 1 if device uid should be checked against the ruid
243  *
244  * Parse mount options:
245  * debug=N         - ecryptfs_verbosity level for debug output
246  * sig=XXX         - description(signature) of the key to use
247  *
248  * Returns the dentry object of the lower-level (lower/interposed)
249  * directory; We want to mount our stackable file system on top of
250  * that lower directory.
251  *
252  * The signature of the key to use must be the description of a key
253  * already in the keyring. Mounting will fail if the key can not be
254  * found.
255  *
256  * Returns zero on success; non-zero on error
257  */
258 static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
259                                   uid_t *check_ruid)
260 {
261         char *p;
262         int rc = 0;
263         int sig_set = 0;
264         int cipher_name_set = 0;
265         int fn_cipher_name_set = 0;
266         int cipher_key_bytes;
267         int cipher_key_bytes_set = 0;
268         int fn_cipher_key_bytes;
269         int fn_cipher_key_bytes_set = 0;
270         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
271                 &sbi->mount_crypt_stat;
272         substring_t args[MAX_OPT_ARGS];
273         int token;
274         char *sig_src;
275         char *cipher_name_dst;
276         char *cipher_name_src;
277         char *fn_cipher_name_dst;
278         char *fn_cipher_name_src;
279         char *fnek_dst;
280         char *fnek_src;
281         char *cipher_key_bytes_src;
282         char *fn_cipher_key_bytes_src;
283         u8 cipher_code;
284 
285         *check_ruid = 0;
286 
287         if (!options) {
288                 rc = -EINVAL;
289                 goto out;
290         }
291         ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
292         while ((p = strsep(&options, ",")) != NULL) {
293                 if (!*p)
294                         continue;
295                 token = match_token(p, tokens, args);
296                 switch (token) {
297                 case ecryptfs_opt_sig:
298                 case ecryptfs_opt_ecryptfs_sig:
299                         sig_src = args[0].from;
300                         rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
301                                                           sig_src, 0);
302                         if (rc) {
303                                 printk(KERN_ERR "Error attempting to register "
304                                        "global sig; rc = [%d]\n", rc);
305                                 goto out;
306                         }
307                         sig_set = 1;
308                         break;
309                 case ecryptfs_opt_cipher:
310                 case ecryptfs_opt_ecryptfs_cipher:
311                         cipher_name_src = args[0].from;
312                         cipher_name_dst =
313                                 mount_crypt_stat->
314                                 global_default_cipher_name;
315                         strncpy(cipher_name_dst, cipher_name_src,
316                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
317                         cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
318                         cipher_name_set = 1;
319                         break;
320                 case ecryptfs_opt_ecryptfs_key_bytes:
321                         cipher_key_bytes_src = args[0].from;
322                         cipher_key_bytes =
323                                 (int)simple_strtol(cipher_key_bytes_src,
324                                                    &cipher_key_bytes_src, 0);
325                         mount_crypt_stat->global_default_cipher_key_size =
326                                 cipher_key_bytes;
327                         cipher_key_bytes_set = 1;
328                         break;
329                 case ecryptfs_opt_passthrough:
330                         mount_crypt_stat->flags |=
331                                 ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
332                         break;
333                 case ecryptfs_opt_xattr_metadata:
334                         mount_crypt_stat->flags |=
335                                 ECRYPTFS_XATTR_METADATA_ENABLED;
336                         break;
337                 case ecryptfs_opt_encrypted_view:
338                         mount_crypt_stat->flags |=
339                                 ECRYPTFS_XATTR_METADATA_ENABLED;
340                         mount_crypt_stat->flags |=
341                                 ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
342                         break;
343                 case ecryptfs_opt_fnek_sig:
344                         fnek_src = args[0].from;
345                         fnek_dst =
346                                 mount_crypt_stat->global_default_fnek_sig;
347                         strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
348                         mount_crypt_stat->global_default_fnek_sig[
349                                 ECRYPTFS_SIG_SIZE_HEX] = '\0';
350                         rc = ecryptfs_add_global_auth_tok(
351                                 mount_crypt_stat,
352                                 mount_crypt_stat->global_default_fnek_sig,
353                                 ECRYPTFS_AUTH_TOK_FNEK);
354                         if (rc) {
355                                 printk(KERN_ERR "Error attempting to register "
356                                        "global fnek sig [%s]; rc = [%d]\n",
357                                        mount_crypt_stat->global_default_fnek_sig,
358                                        rc);
359                                 goto out;
360                         }
361                         mount_crypt_stat->flags |=
362                                 (ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
363                                  | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
364                         break;
365                 case ecryptfs_opt_fn_cipher:
366                         fn_cipher_name_src = args[0].from;
367                         fn_cipher_name_dst =
368                                 mount_crypt_stat->global_default_fn_cipher_name;
369                         strncpy(fn_cipher_name_dst, fn_cipher_name_src,
370                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
371                         mount_crypt_stat->global_default_fn_cipher_name[
372                                 ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
373                         fn_cipher_name_set = 1;
374                         break;
375                 case ecryptfs_opt_fn_cipher_key_bytes:
376                         fn_cipher_key_bytes_src = args[0].from;
377                         fn_cipher_key_bytes =
378                                 (int)simple_strtol(fn_cipher_key_bytes_src,
379                                                    &fn_cipher_key_bytes_src, 0);
380                         mount_crypt_stat->global_default_fn_cipher_key_bytes =
381                                 fn_cipher_key_bytes;
382                         fn_cipher_key_bytes_set = 1;
383                         break;
384                 case ecryptfs_opt_unlink_sigs:
385                         mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
386                         break;
387                 case ecryptfs_opt_mount_auth_tok_only:
388                         mount_crypt_stat->flags |=
389                                 ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
390                         break;
391                 case ecryptfs_opt_check_dev_ruid:
392                         *check_ruid = 1;
393                         break;
394                 case ecryptfs_opt_err:
395                 default:
396                         printk(KERN_WARNING
397                                "%s: eCryptfs: unrecognized option [%s]\n",
398                                __func__, p);
399                 }
400         }
401         if (!sig_set) {
402                 rc = -EINVAL;
403                 ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
404                                 "auth tok signature as a mount "
405                                 "parameter; see the eCryptfs README\n");
406                 goto out;
407         }
408         if (!cipher_name_set) {
409                 int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
410 
411                 BUG_ON(cipher_name_len >= ECRYPTFS_MAX_CIPHER_NAME_SIZE);
412                 strcpy(mount_crypt_stat->global_default_cipher_name,
413                        ECRYPTFS_DEFAULT_CIPHER);
414         }
415         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
416             && !fn_cipher_name_set)
417                 strcpy(mount_crypt_stat->global_default_fn_cipher_name,
418                        mount_crypt_stat->global_default_cipher_name);
419         if (!cipher_key_bytes_set)
420                 mount_crypt_stat->global_default_cipher_key_size = 0;
421         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
422             && !fn_cipher_key_bytes_set)
423                 mount_crypt_stat->global_default_fn_cipher_key_bytes =
424                         mount_crypt_stat->global_default_cipher_key_size;
425 
426         cipher_code = ecryptfs_code_for_cipher_string(
427                 mount_crypt_stat->global_default_cipher_name,
428                 mount_crypt_stat->global_default_cipher_key_size);
429         if (!cipher_code) {
430                 ecryptfs_printk(KERN_ERR,
431                                 "eCryptfs doesn't support cipher: %s",
432                                 mount_crypt_stat->global_default_cipher_name);
433                 rc = -EINVAL;
434                 goto out;
435         }
436 
437         mutex_lock(&key_tfm_list_mutex);
438         if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
439                                  NULL)) {
440                 rc = ecryptfs_add_new_key_tfm(
441                         NULL, mount_crypt_stat->global_default_cipher_name,
442                         mount_crypt_stat->global_default_cipher_key_size);
443                 if (rc) {
444                         printk(KERN_ERR "Error attempting to initialize "
445                                "cipher with name = [%s] and key size = [%td]; "
446                                "rc = [%d]\n",
447                                mount_crypt_stat->global_default_cipher_name,
448                                mount_crypt_stat->global_default_cipher_key_size,
449                                rc);
450                         rc = -EINVAL;
451                         mutex_unlock(&key_tfm_list_mutex);
452                         goto out;
453                 }
454         }
455         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
456             && !ecryptfs_tfm_exists(
457                     mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
458                 rc = ecryptfs_add_new_key_tfm(
459                         NULL, mount_crypt_stat->global_default_fn_cipher_name,
460                         mount_crypt_stat->global_default_fn_cipher_key_bytes);
461                 if (rc) {
462                         printk(KERN_ERR "Error attempting to initialize "
463                                "cipher with name = [%s] and key size = [%td]; "
464                                "rc = [%d]\n",
465                                mount_crypt_stat->global_default_fn_cipher_name,
466                                mount_crypt_stat->global_default_fn_cipher_key_bytes,
467                                rc);
468                         rc = -EINVAL;
469                         mutex_unlock(&key_tfm_list_mutex);
470                         goto out;
471                 }
472         }
473         mutex_unlock(&key_tfm_list_mutex);
474         rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
475         if (rc)
476                 printk(KERN_WARNING "One or more global auth toks could not "
477                        "properly register; rc = [%d]\n", rc);
478 out:
479         return rc;
480 }
481 
482 struct kmem_cache *ecryptfs_sb_info_cache;
483 static struct file_system_type ecryptfs_fs_type;
484 
485 /**
486  * ecryptfs_get_sb
487  * @fs_type
488  * @flags
489  * @dev_name: The path to mount over
490  * @raw_data: The options passed into the kernel
491  */
492 static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
493                         const char *dev_name, void *raw_data)
494 {
495         struct super_block *s;
496         struct ecryptfs_sb_info *sbi;
497         struct ecryptfs_dentry_info *root_info;
498         const char *err = "Getting sb failed";
499         struct inode *inode;
500         struct path path;
501         uid_t check_ruid;
502         int rc;
503 
504         sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
505         if (!sbi) {
506                 rc = -ENOMEM;
507                 goto out;
508         }
509 
510         rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
511         if (rc) {
512                 err = "Error parsing options";
513                 goto out;
514         }
515 
516         s = sget(fs_type, NULL, set_anon_super, flags, NULL);
517         if (IS_ERR(s)) {
518                 rc = PTR_ERR(s);
519                 goto out;
520         }
521 
522         rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs", BDI_CAP_MAP_COPY);
523         if (rc)
524                 goto out1;
525 
526         ecryptfs_set_superblock_private(s, sbi);
527         s->s_bdi = &sbi->bdi;
528 
529         /* ->kill_sb() will take care of sbi after that point */
530         sbi = NULL;
531         s->s_op = &ecryptfs_sops;
532         s->s_d_op = &ecryptfs_dops;
533 
534         err = "Reading sb failed";
535         rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
536         if (rc) {
537                 ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
538                 goto out1;
539         }
540         if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
541                 rc = -EINVAL;
542                 printk(KERN_ERR "Mount on filesystem of type "
543                         "eCryptfs explicitly disallowed due to "
544                         "known incompatibilities\n");
545                 goto out_free;
546         }
547 
548         if (check_ruid && !uid_eq(path.dentry->d_inode->i_uid, current_uid())) {
549                 rc = -EPERM;
550                 printk(KERN_ERR "Mount of device (uid: %d) not owned by "
551                        "requested user (uid: %d)\n",
552                         i_uid_read(path.dentry->d_inode),
553                         from_kuid(&init_user_ns, current_uid()));
554                 goto out_free;
555         }
556 
557         ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
558 
559         /**
560          * Set the POSIX ACL flag based on whether they're enabled in the lower
561          * mount. Force a read-only eCryptfs mount if the lower mount is ro.
562          * Allow a ro eCryptfs mount even when the lower mount is rw.
563          */
564         s->s_flags = flags & ~MS_POSIXACL;
565         s->s_flags |= path.dentry->d_sb->s_flags & (MS_RDONLY | MS_POSIXACL);
566 
567         s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
568         s->s_blocksize = path.dentry->d_sb->s_blocksize;
569         s->s_magic = ECRYPTFS_SUPER_MAGIC;
570 
571         inode = ecryptfs_get_inode(path.dentry->d_inode, s);
572         rc = PTR_ERR(inode);
573         if (IS_ERR(inode))
574                 goto out_free;
575 
576         s->s_root = d_make_root(inode);
577         if (!s->s_root) {
578                 rc = -ENOMEM;
579                 goto out_free;
580         }
581 
582         rc = -ENOMEM;
583         root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
584         if (!root_info)
585                 goto out_free;
586 
587         /* ->kill_sb() will take care of root_info */
588         ecryptfs_set_dentry_private(s->s_root, root_info);
589         ecryptfs_set_dentry_lower(s->s_root, path.dentry);
590         ecryptfs_set_dentry_lower_mnt(s->s_root, path.mnt);
591 
592         s->s_flags |= MS_ACTIVE;
593         return dget(s->s_root);
594 
595 out_free:
596         path_put(&path);
597 out1:
598         deactivate_locked_super(s);
599 out:
600         if (sbi) {
601                 ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
602                 kmem_cache_free(ecryptfs_sb_info_cache, sbi);
603         }
604         printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
605         return ERR_PTR(rc);
606 }
607 
608 /**
609  * ecryptfs_kill_block_super
610  * @sb: The ecryptfs super block
611  *
612  * Used to bring the superblock down and free the private data.
613  */
614 static void ecryptfs_kill_block_super(struct super_block *sb)
615 {
616         struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
617         kill_anon_super(sb);
618         if (!sb_info)
619                 return;
620         ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
621         bdi_destroy(&sb_info->bdi);
622         kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
623 }
624 
625 static struct file_system_type ecryptfs_fs_type = {
626         .owner = THIS_MODULE,
627         .name = "ecryptfs",
628         .mount = ecryptfs_mount,
629         .kill_sb = ecryptfs_kill_block_super,
630         .fs_flags = 0
631 };
632 
633 /**
634  * inode_info_init_once
635  *
636  * Initializes the ecryptfs_inode_info_cache when it is created
637  */
638 static void
639 inode_info_init_once(void *vptr)
640 {
641         struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
642 
643         inode_init_once(&ei->vfs_inode);
644 }
645 
646 static struct ecryptfs_cache_info {
647         struct kmem_cache **cache;
648         const char *name;
649         size_t size;
650         void (*ctor)(void *obj);
651 } ecryptfs_cache_infos[] = {
652         {
653                 .cache = &ecryptfs_auth_tok_list_item_cache,
654                 .name = "ecryptfs_auth_tok_list_item",
655                 .size = sizeof(struct ecryptfs_auth_tok_list_item),
656         },
657         {
658                 .cache = &ecryptfs_file_info_cache,
659                 .name = "ecryptfs_file_cache",
660                 .size = sizeof(struct ecryptfs_file_info),
661         },
662         {
663                 .cache = &ecryptfs_dentry_info_cache,
664                 .name = "ecryptfs_dentry_info_cache",
665                 .size = sizeof(struct ecryptfs_dentry_info),
666         },
667         {
668                 .cache = &ecryptfs_inode_info_cache,
669                 .name = "ecryptfs_inode_cache",
670                 .size = sizeof(struct ecryptfs_inode_info),
671                 .ctor = inode_info_init_once,
672         },
673         {
674                 .cache = &ecryptfs_sb_info_cache,
675                 .name = "ecryptfs_sb_cache",
676                 .size = sizeof(struct ecryptfs_sb_info),
677         },
678         {
679                 .cache = &ecryptfs_header_cache,
680                 .name = "ecryptfs_headers",
681                 .size = PAGE_CACHE_SIZE,
682         },
683         {
684                 .cache = &ecryptfs_xattr_cache,
685                 .name = "ecryptfs_xattr_cache",
686                 .size = PAGE_CACHE_SIZE,
687         },
688         {
689                 .cache = &ecryptfs_key_record_cache,
690                 .name = "ecryptfs_key_record_cache",
691                 .size = sizeof(struct ecryptfs_key_record),
692         },
693         {
694                 .cache = &ecryptfs_key_sig_cache,
695                 .name = "ecryptfs_key_sig_cache",
696                 .size = sizeof(struct ecryptfs_key_sig),
697         },
698         {
699                 .cache = &ecryptfs_global_auth_tok_cache,
700                 .name = "ecryptfs_global_auth_tok_cache",
701                 .size = sizeof(struct ecryptfs_global_auth_tok),
702         },
703         {
704                 .cache = &ecryptfs_key_tfm_cache,
705                 .name = "ecryptfs_key_tfm_cache",
706                 .size = sizeof(struct ecryptfs_key_tfm),
707         },
708 };
709 
710 static void ecryptfs_free_kmem_caches(void)
711 {
712         int i;
713 
714         /*
715          * Make sure all delayed rcu free inodes are flushed before we
716          * destroy cache.
717          */
718         rcu_barrier();
719 
720         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
721                 struct ecryptfs_cache_info *info;
722 
723                 info = &ecryptfs_cache_infos[i];
724                 if (*(info->cache))
725                         kmem_cache_destroy(*(info->cache));
726         }
727 }
728 
729 /**
730  * ecryptfs_init_kmem_caches
731  *
732  * Returns zero on success; non-zero otherwise
733  */
734 static int ecryptfs_init_kmem_caches(void)
735 {
736         int i;
737 
738         for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
739                 struct ecryptfs_cache_info *info;
740 
741                 info = &ecryptfs_cache_infos[i];
742                 *(info->cache) = kmem_cache_create(info->name, info->size,
743                                 0, SLAB_HWCACHE_ALIGN, info->ctor);
744                 if (!*(info->cache)) {
745                         ecryptfs_free_kmem_caches();
746                         ecryptfs_printk(KERN_WARNING, "%s: "
747                                         "kmem_cache_create failed\n",
748                                         info->name);
749                         return -ENOMEM;
750                 }
751         }
752         return 0;
753 }
754 
755 static struct kobject *ecryptfs_kobj;
756 
757 static ssize_t version_show(struct kobject *kobj,
758                             struct kobj_attribute *attr, char *buff)
759 {
760         return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
761 }
762 
763 static struct kobj_attribute version_attr = __ATTR_RO(version);
764 
765 static struct attribute *attributes[] = {
766         &version_attr.attr,
767         NULL,
768 };
769 
770 static struct attribute_group attr_group = {
771         .attrs = attributes,
772 };
773 
774 static int do_sysfs_registration(void)
775 {
776         int rc;
777 
778         ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
779         if (!ecryptfs_kobj) {
780                 printk(KERN_ERR "Unable to create ecryptfs kset\n");
781                 rc = -ENOMEM;
782                 goto out;
783         }
784         rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
785         if (rc) {
786                 printk(KERN_ERR
787                        "Unable to create ecryptfs version attributes\n");
788                 kobject_put(ecryptfs_kobj);
789         }
790 out:
791         return rc;
792 }
793 
794 static void do_sysfs_unregistration(void)
795 {
796         sysfs_remove_group(ecryptfs_kobj, &attr_group);
797         kobject_put(ecryptfs_kobj);
798 }
799 
800 static int __init ecryptfs_init(void)
801 {
802         int rc;
803 
804         if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_CACHE_SIZE) {
805                 rc = -EINVAL;
806                 ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
807                                 "larger than the host's page size, and so "
808                                 "eCryptfs cannot run on this system. The "
809                                 "default eCryptfs extent size is [%u] bytes; "
810                                 "the page size is [%lu] bytes.\n",
811                                 ECRYPTFS_DEFAULT_EXTENT_SIZE,
812                                 (unsigned long)PAGE_CACHE_SIZE);
813                 goto out;
814         }
815         rc = ecryptfs_init_kmem_caches();
816         if (rc) {
817                 printk(KERN_ERR
818                        "Failed to allocate one or more kmem_cache objects\n");
819                 goto out;
820         }
821         rc = do_sysfs_registration();
822         if (rc) {
823                 printk(KERN_ERR "sysfs registration failed\n");
824                 goto out_free_kmem_caches;
825         }
826         rc = ecryptfs_init_kthread();
827         if (rc) {
828                 printk(KERN_ERR "%s: kthread initialization failed; "
829                        "rc = [%d]\n", __func__, rc);
830                 goto out_do_sysfs_unregistration;
831         }
832         rc = ecryptfs_init_messaging();
833         if (rc) {
834                 printk(KERN_ERR "Failure occurred while attempting to "
835                                 "initialize the communications channel to "
836                                 "ecryptfsd\n");
837                 goto out_destroy_kthread;
838         }
839         rc = ecryptfs_init_crypto();
840         if (rc) {
841                 printk(KERN_ERR "Failure whilst attempting to init crypto; "
842                        "rc = [%d]\n", rc);
843                 goto out_release_messaging;
844         }
845         rc = register_filesystem(&ecryptfs_fs_type);
846         if (rc) {
847                 printk(KERN_ERR "Failed to register filesystem\n");
848                 goto out_destroy_crypto;
849         }
850         if (ecryptfs_verbosity > 0)
851                 printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
852                         "will be written to the syslog!\n", ecryptfs_verbosity);
853 
854         goto out;
855 out_destroy_crypto:
856         ecryptfs_destroy_crypto();
857 out_release_messaging:
858         ecryptfs_release_messaging();
859 out_destroy_kthread:
860         ecryptfs_destroy_kthread();
861 out_do_sysfs_unregistration:
862         do_sysfs_unregistration();
863 out_free_kmem_caches:
864         ecryptfs_free_kmem_caches();
865 out:
866         return rc;
867 }
868 
869 static void __exit ecryptfs_exit(void)
870 {
871         int rc;
872 
873         rc = ecryptfs_destroy_crypto();
874         if (rc)
875                 printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
876                        "rc = [%d]\n", rc);
877         ecryptfs_release_messaging();
878         ecryptfs_destroy_kthread();
879         do_sysfs_unregistration();
880         unregister_filesystem(&ecryptfs_fs_type);
881         ecryptfs_free_kmem_caches();
882 }
883 
884 MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
885 MODULE_DESCRIPTION("eCryptfs");
886 
887 MODULE_LICENSE("GPL");
888 
889 module_init(ecryptfs_init)
890 module_exit(ecryptfs_exit)
891 

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