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178 lines
5.4 KiB
178 lines
5.4 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* eCryptfs: Linux filesystem encryption layer |
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* |
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* Copyright (C) 1997-2003 Erez Zadok |
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* Copyright (C) 2001-2003 Stony Brook University |
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* Copyright (C) 2004-2006 International Business Machines Corp. |
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* Author(s): Michael A. Halcrow <[email protected]> |
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* Michael C. Thompson <[email protected]> |
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*/ |
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#include <linux/fs.h> |
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#include <linux/mount.h> |
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#include <linux/key.h> |
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#include <linux/slab.h> |
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#include <linux/seq_file.h> |
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#include <linux/file.h> |
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#include <linux/statfs.h> |
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#include <linux/magic.h> |
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#include "ecryptfs_kernel.h" |
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struct kmem_cache *ecryptfs_inode_info_cache; |
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/** |
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* ecryptfs_alloc_inode - allocate an ecryptfs inode |
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* @sb: Pointer to the ecryptfs super block |
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* |
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* Called to bring an inode into existence. |
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* |
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* Only handle allocation, setting up structures should be done in |
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* ecryptfs_read_inode. This is because the kernel, between now and |
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* then, will 0 out the private data pointer. |
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* |
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* Returns a pointer to a newly allocated inode, NULL otherwise |
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*/ |
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static struct inode *ecryptfs_alloc_inode(struct super_block *sb) |
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{ |
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struct ecryptfs_inode_info *inode_info; |
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struct inode *inode = NULL; |
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inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL); |
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if (unlikely(!inode_info)) |
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goto out; |
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if (ecryptfs_init_crypt_stat(&inode_info->crypt_stat)) { |
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kmem_cache_free(ecryptfs_inode_info_cache, inode_info); |
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goto out; |
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} |
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mutex_init(&inode_info->lower_file_mutex); |
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atomic_set(&inode_info->lower_file_count, 0); |
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inode_info->lower_file = NULL; |
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inode = &inode_info->vfs_inode; |
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out: |
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return inode; |
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} |
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static void ecryptfs_free_inode(struct inode *inode) |
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{ |
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struct ecryptfs_inode_info *inode_info; |
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inode_info = ecryptfs_inode_to_private(inode); |
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kmem_cache_free(ecryptfs_inode_info_cache, inode_info); |
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} |
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/** |
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* ecryptfs_destroy_inode |
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* @inode: The ecryptfs inode |
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* |
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* This is used during the final destruction of the inode. All |
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* allocation of memory related to the inode, including allocated |
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* memory in the crypt_stat struct, will be released here. |
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* There should be no chance that this deallocation will be missed. |
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*/ |
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static void ecryptfs_destroy_inode(struct inode *inode) |
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{ |
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struct ecryptfs_inode_info *inode_info; |
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inode_info = ecryptfs_inode_to_private(inode); |
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BUG_ON(inode_info->lower_file); |
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ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat); |
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} |
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/** |
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* ecryptfs_statfs |
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* @dentry: The ecryptfs dentry |
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* @buf: The struct kstatfs to fill in with stats |
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* |
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* Get the filesystem statistics. Currently, we let this pass right through |
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* to the lower filesystem and take no action ourselves. |
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*/ |
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static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf) |
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{ |
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struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); |
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int rc; |
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if (!lower_dentry->d_sb->s_op->statfs) |
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return -ENOSYS; |
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rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf); |
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if (rc) |
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return rc; |
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buf->f_type = ECRYPTFS_SUPER_MAGIC; |
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rc = ecryptfs_set_f_namelen(&buf->f_namelen, buf->f_namelen, |
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&ecryptfs_superblock_to_private(dentry->d_sb)->mount_crypt_stat); |
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return rc; |
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} |
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/** |
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* ecryptfs_evict_inode |
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* @inode: The ecryptfs inode |
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* |
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* Called by iput() when the inode reference count reached zero |
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* and the inode is not hashed anywhere. Used to clear anything |
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* that needs to be, before the inode is completely destroyed and put |
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* on the inode free list. We use this to drop out reference to the |
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* lower inode. |
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*/ |
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static void ecryptfs_evict_inode(struct inode *inode) |
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{ |
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truncate_inode_pages_final(&inode->i_data); |
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clear_inode(inode); |
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iput(ecryptfs_inode_to_lower(inode)); |
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} |
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/* |
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* ecryptfs_show_options |
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* |
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* Prints the mount options for a given superblock. |
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* Returns zero; does not fail. |
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*/ |
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static int ecryptfs_show_options(struct seq_file *m, struct dentry *root) |
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{ |
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struct super_block *sb = root->d_sb; |
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struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
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&ecryptfs_superblock_to_private(sb)->mount_crypt_stat; |
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struct ecryptfs_global_auth_tok *walker; |
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mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
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list_for_each_entry(walker, |
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&mount_crypt_stat->global_auth_tok_list, |
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mount_crypt_stat_list) { |
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if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK) |
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seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig); |
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else |
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seq_printf(m, ",ecryptfs_sig=%s", walker->sig); |
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} |
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mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
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seq_printf(m, ",ecryptfs_cipher=%s", |
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mount_crypt_stat->global_default_cipher_name); |
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if (mount_crypt_stat->global_default_cipher_key_size) |
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seq_printf(m, ",ecryptfs_key_bytes=%zd", |
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mount_crypt_stat->global_default_cipher_key_size); |
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if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) |
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seq_printf(m, ",ecryptfs_passthrough"); |
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if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) |
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seq_printf(m, ",ecryptfs_xattr_metadata"); |
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if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) |
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seq_printf(m, ",ecryptfs_encrypted_view"); |
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if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS) |
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seq_printf(m, ",ecryptfs_unlink_sigs"); |
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if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) |
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seq_printf(m, ",ecryptfs_mount_auth_tok_only"); |
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return 0; |
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} |
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const struct super_operations ecryptfs_sops = { |
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.alloc_inode = ecryptfs_alloc_inode, |
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.destroy_inode = ecryptfs_destroy_inode, |
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.free_inode = ecryptfs_free_inode, |
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.statfs = ecryptfs_statfs, |
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.remount_fs = NULL, |
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.evict_inode = ecryptfs_evict_inode, |
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.show_options = ecryptfs_show_options |
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};
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