192 lines
6.0 KiB
C
192 lines
6.0 KiB
C
/**
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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 <mahalcro@us.ibm.com>
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* Michael C. Thompson <mcthomps@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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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/crypto.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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ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
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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_i_callback(struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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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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call_rcu(&inode->i_rcu, ecryptfs_i_callback);
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}
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/**
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* ecryptfs_statfs
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* @sb: The ecryptfs super block
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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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.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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