1237fead6SMichael Halcrow /** 2237fead6SMichael Halcrow * eCryptfs: Linux filesystem encryption layer 3237fead6SMichael Halcrow * 4237fead6SMichael Halcrow * Copyright (C) 1997-2003 Erez Zadok 5237fead6SMichael Halcrow * Copyright (C) 2001-2003 Stony Brook University 6237fead6SMichael Halcrow * Copyright (C) 2004-2006 International Business Machines Corp. 7237fead6SMichael Halcrow * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> 8237fead6SMichael Halcrow * Michael C. Thompson <mcthomps@us.ibm.com> 9237fead6SMichael Halcrow * 10237fead6SMichael Halcrow * This program is free software; you can redistribute it and/or 11237fead6SMichael Halcrow * modify it under the terms of the GNU General Public License as 12237fead6SMichael Halcrow * published by the Free Software Foundation; either version 2 of the 13237fead6SMichael Halcrow * License, or (at your option) any later version. 14237fead6SMichael Halcrow * 15237fead6SMichael Halcrow * This program is distributed in the hope that it will be useful, but 16237fead6SMichael Halcrow * WITHOUT ANY WARRANTY; without even the implied warranty of 17237fead6SMichael Halcrow * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18237fead6SMichael Halcrow * General Public License for more details. 19237fead6SMichael Halcrow * 20237fead6SMichael Halcrow * You should have received a copy of the GNU General Public License 21237fead6SMichael Halcrow * along with this program; if not, write to the Free Software 22237fead6SMichael Halcrow * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 23237fead6SMichael Halcrow * 02111-1307, USA. 24237fead6SMichael Halcrow */ 25237fead6SMichael Halcrow 26237fead6SMichael Halcrow #include <linux/fs.h> 27237fead6SMichael Halcrow #include <linux/mount.h> 28237fead6SMichael Halcrow #include <linux/key.h> 29237fead6SMichael Halcrow #include <linux/seq_file.h> 304981e081SMichael Halcrow #include <linux/file.h> 31237fead6SMichael Halcrow #include <linux/crypto.h> 32237fead6SMichael Halcrow #include "ecryptfs_kernel.h" 33237fead6SMichael Halcrow 34237fead6SMichael Halcrow struct kmem_cache *ecryptfs_inode_info_cache; 35237fead6SMichael Halcrow 36237fead6SMichael Halcrow /** 37237fead6SMichael Halcrow * ecryptfs_alloc_inode - allocate an ecryptfs inode 38237fead6SMichael Halcrow * @sb: Pointer to the ecryptfs super block 39237fead6SMichael Halcrow * 40237fead6SMichael Halcrow * Called to bring an inode into existence. 41237fead6SMichael Halcrow * 42237fead6SMichael Halcrow * Only handle allocation, setting up structures should be done in 43237fead6SMichael Halcrow * ecryptfs_read_inode. This is because the kernel, between now and 44237fead6SMichael Halcrow * then, will 0 out the private data pointer. 45237fead6SMichael Halcrow * 46237fead6SMichael Halcrow * Returns a pointer to a newly allocated inode, NULL otherwise 47237fead6SMichael Halcrow */ 48237fead6SMichael Halcrow static struct inode *ecryptfs_alloc_inode(struct super_block *sb) 49237fead6SMichael Halcrow { 50237fead6SMichael Halcrow struct ecryptfs_inode_info *ecryptfs_inode; 51237fead6SMichael Halcrow struct inode *inode = NULL; 52237fead6SMichael Halcrow 53237fead6SMichael Halcrow ecryptfs_inode = kmem_cache_alloc(ecryptfs_inode_info_cache, 54e94b1766SChristoph Lameter GFP_KERNEL); 55237fead6SMichael Halcrow if (unlikely(!ecryptfs_inode)) 56237fead6SMichael Halcrow goto out; 57237fead6SMichael Halcrow ecryptfs_init_crypt_stat(&ecryptfs_inode->crypt_stat); 58237fead6SMichael Halcrow inode = &ecryptfs_inode->vfs_inode; 59237fead6SMichael Halcrow out: 60237fead6SMichael Halcrow return inode; 61237fead6SMichael Halcrow } 62237fead6SMichael Halcrow 63237fead6SMichael Halcrow /** 64237fead6SMichael Halcrow * ecryptfs_destroy_inode 65237fead6SMichael Halcrow * @inode: The ecryptfs inode 66237fead6SMichael Halcrow * 674981e081SMichael Halcrow * This is used during the final destruction of the inode. All 684981e081SMichael Halcrow * allocation of memory related to the inode, including allocated 694981e081SMichael Halcrow * memory in the crypt_stat struct, will be released here. This 704981e081SMichael Halcrow * function also fput()'s the persistent file for the lower inode. 71237fead6SMichael Halcrow * There should be no chance that this deallocation will be missed. 72237fead6SMichael Halcrow */ 73237fead6SMichael Halcrow static void ecryptfs_destroy_inode(struct inode *inode) 74237fead6SMichael Halcrow { 75237fead6SMichael Halcrow struct ecryptfs_inode_info *inode_info; 76237fead6SMichael Halcrow 77237fead6SMichael Halcrow inode_info = ecryptfs_inode_to_private(inode); 784981e081SMichael Halcrow mutex_lock(&inode_info->lower_file_mutex); 794981e081SMichael Halcrow if (inode_info->lower_file) { 804981e081SMichael Halcrow struct dentry *lower_dentry = 814981e081SMichael Halcrow inode_info->lower_file->f_dentry; 824981e081SMichael Halcrow 834981e081SMichael Halcrow BUG_ON(!lower_dentry); 844981e081SMichael Halcrow if (lower_dentry->d_inode) { 854981e081SMichael Halcrow fput(inode_info->lower_file); 864981e081SMichael Halcrow inode_info->lower_file = NULL; 874981e081SMichael Halcrow d_drop(lower_dentry); 884981e081SMichael Halcrow d_delete(lower_dentry); 894981e081SMichael Halcrow } 904981e081SMichael Halcrow } 914981e081SMichael Halcrow mutex_unlock(&inode_info->lower_file_mutex); 92fcd12835SMichael Halcrow ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat); 93237fead6SMichael Halcrow kmem_cache_free(ecryptfs_inode_info_cache, inode_info); 94237fead6SMichael Halcrow } 95237fead6SMichael Halcrow 96237fead6SMichael Halcrow /** 97237fead6SMichael Halcrow * ecryptfs_init_inode 98237fead6SMichael Halcrow * @inode: The ecryptfs inode 99237fead6SMichael Halcrow * 100237fead6SMichael Halcrow * Set up the ecryptfs inode. 101237fead6SMichael Halcrow */ 102237fead6SMichael Halcrow void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode) 103237fead6SMichael Halcrow { 104237fead6SMichael Halcrow ecryptfs_set_inode_lower(inode, lower_inode); 105237fead6SMichael Halcrow inode->i_ino = lower_inode->i_ino; 106237fead6SMichael Halcrow inode->i_version++; 107237fead6SMichael Halcrow inode->i_op = &ecryptfs_main_iops; 108237fead6SMichael Halcrow inode->i_fop = &ecryptfs_main_fops; 109237fead6SMichael Halcrow inode->i_mapping->a_ops = &ecryptfs_aops; 110237fead6SMichael Halcrow } 111237fead6SMichael Halcrow 112237fead6SMichael Halcrow /** 113237fead6SMichael Halcrow * ecryptfs_put_super 114237fead6SMichael Halcrow * @sb: Pointer to the ecryptfs super block 115237fead6SMichael Halcrow * 116237fead6SMichael Halcrow * Final actions when unmounting a file system. 117237fead6SMichael Halcrow * This will handle deallocation and release of our private data. 118237fead6SMichael Halcrow */ 119237fead6SMichael Halcrow static void ecryptfs_put_super(struct super_block *sb) 120237fead6SMichael Halcrow { 121237fead6SMichael Halcrow struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb); 122237fead6SMichael Halcrow 123fcd12835SMichael Halcrow ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat); 124237fead6SMichael Halcrow kmem_cache_free(ecryptfs_sb_info_cache, sb_info); 125237fead6SMichael Halcrow ecryptfs_set_superblock_private(sb, NULL); 126237fead6SMichael Halcrow } 127237fead6SMichael Halcrow 128237fead6SMichael Halcrow /** 129237fead6SMichael Halcrow * ecryptfs_statfs 130237fead6SMichael Halcrow * @sb: The ecryptfs super block 131237fead6SMichael Halcrow * @buf: The struct kstatfs to fill in with stats 132237fead6SMichael Halcrow * 133237fead6SMichael Halcrow * Get the filesystem statistics. Currently, we let this pass right through 134237fead6SMichael Halcrow * to the lower filesystem and take no action ourselves. 135237fead6SMichael Halcrow */ 136237fead6SMichael Halcrow static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf) 137237fead6SMichael Halcrow { 138237fead6SMichael Halcrow return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf); 139237fead6SMichael Halcrow } 140237fead6SMichael Halcrow 141237fead6SMichael Halcrow /** 142237fead6SMichael Halcrow * ecryptfs_clear_inode 143237fead6SMichael Halcrow * @inode - The ecryptfs inode 144237fead6SMichael Halcrow * 145237fead6SMichael Halcrow * Called by iput() when the inode reference count reached zero 146237fead6SMichael Halcrow * and the inode is not hashed anywhere. Used to clear anything 147237fead6SMichael Halcrow * that needs to be, before the inode is completely destroyed and put 148237fead6SMichael Halcrow * on the inode free list. We use this to drop out reference to the 149237fead6SMichael Halcrow * lower inode. 150237fead6SMichael Halcrow */ 151237fead6SMichael Halcrow static void ecryptfs_clear_inode(struct inode *inode) 152237fead6SMichael Halcrow { 153237fead6SMichael Halcrow iput(ecryptfs_inode_to_lower(inode)); 154237fead6SMichael Halcrow } 155237fead6SMichael Halcrow 156237fead6SMichael Halcrow /** 157237fead6SMichael Halcrow * ecryptfs_show_options 158237fead6SMichael Halcrow * 159237fead6SMichael Halcrow * Prints the directory we are currently mounted over. 160237fead6SMichael Halcrow * Returns zero on success; non-zero otherwise 161237fead6SMichael Halcrow */ 162237fead6SMichael Halcrow static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt) 163237fead6SMichael Halcrow { 164237fead6SMichael Halcrow struct super_block *sb = mnt->mnt_sb; 165237fead6SMichael Halcrow struct dentry *lower_root_dentry = ecryptfs_dentry_to_lower(sb->s_root); 166237fead6SMichael Halcrow struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(sb->s_root); 167237fead6SMichael Halcrow char *tmp_page; 168237fead6SMichael Halcrow char *path; 169237fead6SMichael Halcrow int rc = 0; 170237fead6SMichael Halcrow 171237fead6SMichael Halcrow tmp_page = (char *)__get_free_page(GFP_KERNEL); 172237fead6SMichael Halcrow if (!tmp_page) { 173237fead6SMichael Halcrow rc = -ENOMEM; 174237fead6SMichael Halcrow goto out; 175237fead6SMichael Halcrow } 176237fead6SMichael Halcrow path = d_path(lower_root_dentry, lower_mnt, tmp_page, PAGE_SIZE); 177237fead6SMichael Halcrow if (IS_ERR(path)) { 178237fead6SMichael Halcrow rc = PTR_ERR(path); 179237fead6SMichael Halcrow goto out; 180237fead6SMichael Halcrow } 181237fead6SMichael Halcrow seq_printf(m, ",dir=%s", path); 182237fead6SMichael Halcrow free_page((unsigned long)tmp_page); 183237fead6SMichael Halcrow out: 184237fead6SMichael Halcrow return rc; 185237fead6SMichael Halcrow } 186237fead6SMichael Halcrow 187ee9b6d61SJosef 'Jeff' Sipek const struct super_operations ecryptfs_sops = { 188237fead6SMichael Halcrow .alloc_inode = ecryptfs_alloc_inode, 189237fead6SMichael Halcrow .destroy_inode = ecryptfs_destroy_inode, 190237fead6SMichael Halcrow .drop_inode = generic_delete_inode, 191237fead6SMichael Halcrow .put_super = ecryptfs_put_super, 192237fead6SMichael Halcrow .statfs = ecryptfs_statfs, 193237fead6SMichael Halcrow .remount_fs = NULL, 194237fead6SMichael Halcrow .clear_inode = ecryptfs_clear_inode, 195237fead6SMichael Halcrow .show_options = ecryptfs_show_options 196237fead6SMichael Halcrow }; 197