super.c 6.1 KB

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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) 2004-2006 International Business Machines Corp.
  7. * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  8. * Michael C. Thompson <mcthomps@us.ibm.com>
  9. *
  10. * This program is free software; you can redistribute it and/or
  11. * modify it under the terms of the GNU General Public License as
  12. * published by the Free Software Foundation; either version 2 of the
  13. * License, or (at your option) any later version.
  14. *
  15. * This program is distributed in the hope that it will be useful, but
  16. * WITHOUT ANY WARRANTY; without even the implied warranty of
  17. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18. * General Public License for more details.
  19. *
  20. * You should have received a copy of the GNU General Public License
  21. * along with this program; if not, write to the Free Software
  22. * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  23. * 02111-1307, USA.
  24. */
  25. #include <linux/fs.h>
  26. #include <linux/mount.h>
  27. #include <linux/key.h>
  28. #include <linux/slab.h>
  29. #include <linux/seq_file.h>
  30. #include <linux/file.h>
  31. #include <linux/statfs.h>
  32. #include <linux/magic.h>
  33. #include "ecryptfs_kernel.h"
  34. struct kmem_cache *ecryptfs_inode_info_cache;
  35. /**
  36. * ecryptfs_alloc_inode - allocate an ecryptfs inode
  37. * @sb: Pointer to the ecryptfs super block
  38. *
  39. * Called to bring an inode into existence.
  40. *
  41. * Only handle allocation, setting up structures should be done in
  42. * ecryptfs_read_inode. This is because the kernel, between now and
  43. * then, will 0 out the private data pointer.
  44. *
  45. * Returns a pointer to a newly allocated inode, NULL otherwise
  46. */
  47. static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
  48. {
  49. struct ecryptfs_inode_info *inode_info;
  50. struct inode *inode = NULL;
  51. inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL);
  52. if (unlikely(!inode_info))
  53. goto out;
  54. if (ecryptfs_init_crypt_stat(&inode_info->crypt_stat)) {
  55. kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
  56. goto out;
  57. }
  58. mutex_init(&inode_info->lower_file_mutex);
  59. atomic_set(&inode_info->lower_file_count, 0);
  60. inode_info->lower_file = NULL;
  61. inode = &inode_info->vfs_inode;
  62. out:
  63. return inode;
  64. }
  65. static void ecryptfs_i_callback(struct rcu_head *head)
  66. {
  67. struct inode *inode = container_of(head, struct inode, i_rcu);
  68. struct ecryptfs_inode_info *inode_info;
  69. inode_info = ecryptfs_inode_to_private(inode);
  70. kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
  71. }
  72. /**
  73. * ecryptfs_destroy_inode
  74. * @inode: The ecryptfs inode
  75. *
  76. * This is used during the final destruction of the inode. All
  77. * allocation of memory related to the inode, including allocated
  78. * memory in the crypt_stat struct, will be released here.
  79. * There should be no chance that this deallocation will be missed.
  80. */
  81. static void ecryptfs_destroy_inode(struct inode *inode)
  82. {
  83. struct ecryptfs_inode_info *inode_info;
  84. inode_info = ecryptfs_inode_to_private(inode);
  85. BUG_ON(inode_info->lower_file);
  86. ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
  87. call_rcu(&inode->i_rcu, ecryptfs_i_callback);
  88. }
  89. /**
  90. * ecryptfs_statfs
  91. * @sb: The ecryptfs super block
  92. * @buf: The struct kstatfs to fill in with stats
  93. *
  94. * Get the filesystem statistics. Currently, we let this pass right through
  95. * to the lower filesystem and take no action ourselves.
  96. */
  97. static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
  98. {
  99. struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
  100. int rc;
  101. if (!lower_dentry->d_sb->s_op->statfs)
  102. return -ENOSYS;
  103. rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
  104. if (rc)
  105. return rc;
  106. buf->f_type = ECRYPTFS_SUPER_MAGIC;
  107. rc = ecryptfs_set_f_namelen(&buf->f_namelen, buf->f_namelen,
  108. &ecryptfs_superblock_to_private(dentry->d_sb)->mount_crypt_stat);
  109. return rc;
  110. }
  111. /**
  112. * ecryptfs_evict_inode
  113. * @inode - The ecryptfs inode
  114. *
  115. * Called by iput() when the inode reference count reached zero
  116. * and the inode is not hashed anywhere. Used to clear anything
  117. * that needs to be, before the inode is completely destroyed and put
  118. * on the inode free list. We use this to drop out reference to the
  119. * lower inode.
  120. */
  121. static void ecryptfs_evict_inode(struct inode *inode)
  122. {
  123. truncate_inode_pages_final(&inode->i_data);
  124. clear_inode(inode);
  125. iput(ecryptfs_inode_to_lower(inode));
  126. }
  127. /**
  128. * ecryptfs_show_options
  129. *
  130. * Prints the mount options for a given superblock.
  131. * Returns zero; does not fail.
  132. */
  133. static int ecryptfs_show_options(struct seq_file *m, struct dentry *root)
  134. {
  135. struct super_block *sb = root->d_sb;
  136. struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
  137. &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
  138. struct ecryptfs_global_auth_tok *walker;
  139. mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
  140. list_for_each_entry(walker,
  141. &mount_crypt_stat->global_auth_tok_list,
  142. mount_crypt_stat_list) {
  143. if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
  144. seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
  145. else
  146. seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
  147. }
  148. mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
  149. seq_printf(m, ",ecryptfs_cipher=%s",
  150. mount_crypt_stat->global_default_cipher_name);
  151. if (mount_crypt_stat->global_default_cipher_key_size)
  152. seq_printf(m, ",ecryptfs_key_bytes=%zd",
  153. mount_crypt_stat->global_default_cipher_key_size);
  154. if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
  155. seq_printf(m, ",ecryptfs_passthrough");
  156. if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
  157. seq_printf(m, ",ecryptfs_xattr_metadata");
  158. if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
  159. seq_printf(m, ",ecryptfs_encrypted_view");
  160. if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
  161. seq_printf(m, ",ecryptfs_unlink_sigs");
  162. if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
  163. seq_printf(m, ",ecryptfs_mount_auth_tok_only");
  164. return 0;
  165. }
  166. const struct super_operations ecryptfs_sops = {
  167. .alloc_inode = ecryptfs_alloc_inode,
  168. .destroy_inode = ecryptfs_destroy_inode,
  169. .statfs = ecryptfs_statfs,
  170. .remount_fs = NULL,
  171. .evict_inode = ecryptfs_evict_inode,
  172. .show_options = ecryptfs_show_options
  173. };