diff options
Diffstat (limited to 'fs/ecryptfs/super.c')
| -rw-r--r-- | fs/ecryptfs/super.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/fs/ecryptfs/super.c b/fs/ecryptfs/super.c new file mode 100644 index 000000000..afa1b81c3 --- /dev/null +++ b/fs/ecryptfs/super.c @@ -0,0 +1,191 @@ +/** + * 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_final(&inode->i_data); + 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 +}; |