/** * eCryptfs: Linux filesystem encryption layer * * Copyright (C) 1997-2003 Erez Zadok * Copyright (C) 2001-2003 Stony Brook University * Copyright (C) 2004-2006 International Business Machines Corp. * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> * Michael C. Thompson <mcthomps@us.ibm.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA * 02111-1307, USA. */ #include <linux/fs.h> #include <linux/mount.h> #include <linux/key.h> #include <linux/slab.h> #include <linux/seq_file.h> #include <linux/file.h> #include <linux/crypto.h> #include <linux/statfs.h> #include <linux/magic.h> #include "ecryptfs_kernel.h" struct kmem_cache *ecryptfs_inode_info_cache; /** * ecryptfs_alloc_inode - allocate an ecryptfs inode * @sb: Pointer to the ecryptfs super block * * Called to bring an inode into existence. * * Only handle allocation, setting up structures should be done in * ecryptfs_read_inode. This is because the kernel, between now and * then, will 0 out the private data pointer. * * Returns a pointer to a newly allocated inode, NULL otherwise */ static struct inode *ecryptfs_alloc_inode(struct super_block *sb) { struct ecryptfs_inode_info *inode_info; struct inode *inode = NULL; inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL); if (unlikely(!inode_info)) goto out; ecryptfs_init_crypt_stat(&inode_info->crypt_stat); mutex_init(&inode_info->lower_file_mutex); atomic_set(&inode_info->lower_file_count, 0); inode_info->lower_file = NULL; inode = &inode_info->vfs_inode; out: return inode; } static void ecryptfs_i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); struct ecryptfs_inode_info *inode_info; inode_info = ecryptfs_inode_to_private(inode); kmem_cache_free(ecryptfs_inode_info_cache, inode_info); } /** * ecryptfs_destroy_inode * @inode: The ecryptfs inode * * This is used during the final destruction of the inode. All * allocation of memory related to the inode, including allocated * memory in the crypt_stat struct, will be released here. * There should be no chance that this deallocation will be missed. */ static void ecryptfs_destroy_inode(struct inode *inode) { struct ecryptfs_inode_info *inode_info; inode_info = ecryptfs_inode_to_private(inode); BUG_ON(inode_info->lower_file); ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat); call_rcu(&inode->i_rcu, ecryptfs_i_callback); } /** * ecryptfs_statfs * @sb: The ecryptfs super block * @buf: The struct kstatfs to fill in with stats * * Get the filesystem statistics. Currently, we let this pass right through * to the lower filesystem and take no action ourselves. */ static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf) { struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); int rc; if (!lower_dentry->d_sb->s_op->statfs) return -ENOSYS; rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf); if (rc) return rc; buf->f_type = ECRYPTFS_SUPER_MAGIC; rc = ecryptfs_set_f_namelen(&buf->f_namelen, buf->f_namelen, &ecryptfs_superblock_to_private(dentry->d_sb)->mount_crypt_stat); return rc; } /** * ecryptfs_evict_inode * @inode - The ecryptfs inode * * Called by iput() when the inode reference count reached zero * and the inode is not hashed anywhere. Used to clear anything * that needs to be, before the inode is completely destroyed and put * on the inode free list. We use this to drop out reference to the * lower inode. */ static void ecryptfs_evict_inode(struct inode *inode) { truncate_inode_pages(&inode->i_data, 0); clear_inode(inode); iput(ecryptfs_inode_to_lower(inode)); } /** * ecryptfs_show_options * * Prints the mount options for a given superblock. * Returns zero; does not fail. */ static int ecryptfs_show_options(struct seq_file *m, struct dentry *root) { struct super_block *sb = root->d_sb; struct ecryptfs_mount_crypt_stat *mount_crypt_stat = &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; struct ecryptfs_global_auth_tok *walker; mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); list_for_each_entry(walker, &mount_crypt_stat->global_auth_tok_list, mount_crypt_stat_list) { if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK) seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig); else seq_printf(m, ",ecryptfs_sig=%s", walker->sig); } mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); seq_printf(m, ",ecryptfs_cipher=%s", mount_crypt_stat->global_default_cipher_name); if (mount_crypt_stat->global_default_cipher_key_size) seq_printf(m, ",ecryptfs_key_bytes=%zd", mount_crypt_stat->global_default_cipher_key_size); if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) seq_printf(m, ",ecryptfs_passthrough"); if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) seq_printf(m, ",ecryptfs_xattr_metadata"); if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) seq_printf(m, ",ecryptfs_encrypted_view"); if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS) seq_printf(m, ",ecryptfs_unlink_sigs"); if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY) seq_printf(m, ",ecryptfs_mount_auth_tok_only"); return 0; } const struct super_operations ecryptfs_sops = { .alloc_inode = ecryptfs_alloc_inode, .destroy_inode = ecryptfs_destroy_inode, .statfs = ecryptfs_statfs, .remount_fs = NULL, .evict_inode = ecryptfs_evict_inode, .show_options = ecryptfs_show_options };