| /** |
| * eCryptfs: Linux filesystem encryption layer |
| * |
| * Copyright (C) 1997-2004 Erez Zadok |
| * Copyright (C) 2001-2004 Stony Brook University |
| * Copyright (C) 2004-2007 International Business Machines Corp. |
| * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
| * Michael C. Thompsion <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/file.h> |
| #include <linux/vmalloc.h> |
| #include <linux/pagemap.h> |
| #include <linux/dcache.h> |
| #include <linux/namei.h> |
| #include <linux/mount.h> |
| #include <linux/crypto.h> |
| #include <linux/fs_stack.h> |
| #include <asm/unaligned.h> |
| #include "ecryptfs_kernel.h" |
| |
| static struct dentry *lock_parent(struct dentry *dentry) |
| { |
| struct dentry *dir; |
| |
| dir = dget_parent(dentry); |
| mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT); |
| return dir; |
| } |
| |
| static void unlock_dir(struct dentry *dir) |
| { |
| mutex_unlock(&dir->d_inode->i_mutex); |
| dput(dir); |
| } |
| |
| /** |
| * ecryptfs_create_underlying_file |
| * @lower_dir_inode: inode of the parent in the lower fs of the new file |
| * @lower_dentry: New file's dentry in the lower fs |
| * @ecryptfs_dentry: New file's dentry in ecryptfs |
| * @mode: The mode of the new file |
| * @nd: nameidata of ecryptfs' parent's dentry & vfsmount |
| * |
| * Creates the file in the lower file system. |
| * |
| * Returns zero on success; non-zero on error condition |
| */ |
| static int |
| ecryptfs_create_underlying_file(struct inode *lower_dir_inode, |
| struct dentry *dentry, int mode, |
| struct nameidata *nd) |
| { |
| struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry); |
| struct dentry *dentry_save; |
| struct vfsmount *vfsmount_save; |
| int rc; |
| |
| dentry_save = nd->path.dentry; |
| vfsmount_save = nd->path.mnt; |
| nd->path.dentry = lower_dentry; |
| nd->path.mnt = lower_mnt; |
| rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd); |
| nd->path.dentry = dentry_save; |
| nd->path.mnt = vfsmount_save; |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_do_create |
| * @directory_inode: inode of the new file's dentry's parent in ecryptfs |
| * @ecryptfs_dentry: New file's dentry in ecryptfs |
| * @mode: The mode of the new file |
| * @nd: nameidata of ecryptfs' parent's dentry & vfsmount |
| * |
| * Creates the underlying file and the eCryptfs inode which will link to |
| * it. It will also update the eCryptfs directory inode to mimic the |
| * stat of the lower directory inode. |
| * |
| * Returns zero on success; non-zero on error condition |
| */ |
| static int |
| ecryptfs_do_create(struct inode *directory_inode, |
| struct dentry *ecryptfs_dentry, int mode, |
| struct nameidata *nd) |
| { |
| int rc; |
| struct dentry *lower_dentry; |
| struct dentry *lower_dir_dentry; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
| lower_dir_dentry = lock_parent(lower_dentry); |
| if (IS_ERR(lower_dir_dentry)) { |
| ecryptfs_printk(KERN_ERR, "Error locking directory of " |
| "dentry\n"); |
| rc = PTR_ERR(lower_dir_dentry); |
| goto out; |
| } |
| rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode, |
| ecryptfs_dentry, mode, nd); |
| if (rc) { |
| printk(KERN_ERR "%s: Failure to create dentry in lower fs; " |
| "rc = [%d]\n", __func__, rc); |
| goto out_lock; |
| } |
| rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry, |
| directory_inode->i_sb, 0); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n"); |
| goto out_lock; |
| } |
| fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode); |
| fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode); |
| out_lock: |
| unlock_dir(lower_dir_dentry); |
| out: |
| return rc; |
| } |
| |
| /** |
| * grow_file |
| * @ecryptfs_dentry: the eCryptfs dentry |
| * |
| * This is the code which will grow the file to its correct size. |
| */ |
| static int grow_file(struct dentry *ecryptfs_dentry) |
| { |
| struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; |
| struct file fake_file; |
| struct ecryptfs_file_info tmp_file_info; |
| char zero_virt[] = { 0x00 }; |
| int rc = 0; |
| |
| memset(&fake_file, 0, sizeof(fake_file)); |
| fake_file.f_path.dentry = ecryptfs_dentry; |
| memset(&tmp_file_info, 0, sizeof(tmp_file_info)); |
| ecryptfs_set_file_private(&fake_file, &tmp_file_info); |
| ecryptfs_set_file_lower( |
| &fake_file, |
| ecryptfs_inode_to_private(ecryptfs_inode)->lower_file); |
| rc = ecryptfs_write(&fake_file, zero_virt, 0, 1); |
| i_size_write(ecryptfs_inode, 0); |
| rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode); |
| ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |= |
| ECRYPTFS_NEW_FILE; |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_initialize_file |
| * |
| * Cause the file to be changed from a basic empty file to an ecryptfs |
| * file with a header and first data page. |
| * |
| * Returns zero on success |
| */ |
| static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry) |
| { |
| struct ecryptfs_crypt_stat *crypt_stat = |
| &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; |
| int rc = 0; |
| |
| if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { |
| ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); |
| crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
| goto out; |
| } |
| crypt_stat->flags |= ECRYPTFS_NEW_FILE; |
| ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n"); |
| rc = ecryptfs_new_file_context(ecryptfs_dentry); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error creating new file " |
| "context; rc = [%d]\n", rc); |
| goto out; |
| } |
| rc = ecryptfs_write_metadata(ecryptfs_dentry); |
| if (rc) { |
| printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); |
| goto out; |
| } |
| rc = grow_file(ecryptfs_dentry); |
| if (rc) |
| printk(KERN_ERR "Error growing file; rc = [%d]\n", rc); |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_create |
| * @dir: The inode of the directory in which to create the file. |
| * @dentry: The eCryptfs dentry |
| * @mode: The mode of the new file. |
| * @nd: nameidata |
| * |
| * Creates a new file. |
| * |
| * Returns zero on success; non-zero on error condition |
| */ |
| static int |
| ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry, |
| int mode, struct nameidata *nd) |
| { |
| int rc; |
| |
| /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens |
| * the crypt_stat->lower_file (persistent file) */ |
| rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd); |
| if (unlikely(rc)) { |
| ecryptfs_printk(KERN_WARNING, "Failed to create file in" |
| "lower filesystem\n"); |
| goto out; |
| } |
| /* At this point, a file exists on "disk"; we need to make sure |
| * that this on disk file is prepared to be an ecryptfs file */ |
| rc = ecryptfs_initialize_file(ecryptfs_dentry); |
| out: |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_lookup |
| * @dir: inode |
| * @dentry: The dentry |
| * @nd: nameidata, may be NULL |
| * |
| * Find a file on disk. If the file does not exist, then we'll add it to the |
| * dentry cache and continue on to read it from the disk. |
| */ |
| static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry, |
| struct nameidata *nd) |
| { |
| int rc = 0; |
| struct dentry *lower_dir_dentry; |
| struct dentry *lower_dentry; |
| struct vfsmount *lower_mnt; |
| char *encoded_name; |
| int encoded_namelen; |
| struct ecryptfs_crypt_stat *crypt_stat = NULL; |
| struct ecryptfs_mount_crypt_stat *mount_crypt_stat; |
| char *page_virt = NULL; |
| struct inode *lower_inode; |
| u64 file_size; |
| |
| lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent); |
| dentry->d_op = &ecryptfs_dops; |
| if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, ".")) |
| || (dentry->d_name.len == 2 |
| && !strcmp(dentry->d_name.name, ".."))) { |
| d_drop(dentry); |
| goto out; |
| } |
| encoded_namelen = ecryptfs_encode_filename(crypt_stat, |
| dentry->d_name.name, |
| dentry->d_name.len, |
| &encoded_name); |
| if (encoded_namelen < 0) { |
| rc = encoded_namelen; |
| d_drop(dentry); |
| goto out; |
| } |
| ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen " |
| "= [%d]\n", encoded_name, encoded_namelen); |
| lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry, |
| encoded_namelen - 1); |
| kfree(encoded_name); |
| if (IS_ERR(lower_dentry)) { |
| ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n"); |
| rc = PTR_ERR(lower_dentry); |
| d_drop(dentry); |
| goto out; |
| } |
| lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent)); |
| ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->" |
| "d_name.name = [%s]\n", lower_dentry, |
| lower_dentry->d_name.name); |
| lower_inode = lower_dentry->d_inode; |
| fsstack_copy_attr_atime(dir, lower_dir_dentry->d_inode); |
| BUG_ON(!atomic_read(&lower_dentry->d_count)); |
| ecryptfs_set_dentry_private(dentry, |
| kmem_cache_alloc(ecryptfs_dentry_info_cache, |
| GFP_KERNEL)); |
| if (!ecryptfs_dentry_to_private(dentry)) { |
| rc = -ENOMEM; |
| ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting " |
| "to allocate ecryptfs_dentry_info struct\n"); |
| goto out_dput; |
| } |
| ecryptfs_set_dentry_lower(dentry, lower_dentry); |
| ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt); |
| if (!lower_dentry->d_inode) { |
| /* We want to add because we couldn't find in lower */ |
| d_add(dentry, NULL); |
| goto out; |
| } |
| rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1); |
| if (rc) { |
| ecryptfs_printk(KERN_ERR, "Error interposing\n"); |
| goto out_dput; |
| } |
| if (S_ISDIR(lower_inode->i_mode)) { |
| ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n"); |
| goto out; |
| } |
| if (S_ISLNK(lower_inode->i_mode)) { |
| ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n"); |
| goto out; |
| } |
| if (special_file(lower_inode->i_mode)) { |
| ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n"); |
| goto out; |
| } |
| if (!nd) { |
| ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave" |
| "as we *think* we are about to unlink\n"); |
| goto out; |
| } |
| /* Released in this function */ |
| page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, |
| GFP_USER); |
| if (!page_virt) { |
| rc = -ENOMEM; |
| ecryptfs_printk(KERN_ERR, |
| "Cannot ecryptfs_kmalloc a page\n"); |
| goto out_dput; |
| } |
| crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; |
| if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) |
| ecryptfs_set_default_sizes(crypt_stat); |
| rc = ecryptfs_read_and_validate_header_region(page_virt, |
| dentry->d_inode); |
| if (rc) { |
| rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry); |
| if (rc) { |
| printk(KERN_DEBUG "Valid metadata not found in header " |
| "region or xattr region; treating file as " |
| "unencrypted\n"); |
| rc = 0; |
| kmem_cache_free(ecryptfs_header_cache_2, page_virt); |
| goto out; |
| } |
| crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; |
| } |
| mount_crypt_stat = &ecryptfs_superblock_to_private( |
| dentry->d_sb)->mount_crypt_stat; |
| if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { |
| if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
| file_size = (crypt_stat->num_header_bytes_at_front |
| + i_size_read(lower_dentry->d_inode)); |
| else |
| file_size = i_size_read(lower_dentry->d_inode); |
| } else { |
| file_size = get_unaligned_be64(page_virt); |
| } |
| i_size_write(dentry->d_inode, (loff_t)file_size); |
| kmem_cache_free(ecryptfs_header_cache_2, page_virt); |
| goto out; |
| |
| out_dput: |
| dput(lower_dentry); |
| d_drop(dentry); |
| out: |
| return ERR_PTR(rc); |
| } |
| |
| static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir, |
| struct dentry *new_dentry) |
| { |
| struct dentry *lower_old_dentry; |
| struct dentry *lower_new_dentry; |
| struct dentry *lower_dir_dentry; |
| u64 file_size_save; |
| int rc; |
| |
| file_size_save = i_size_read(old_dentry->d_inode); |
| lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); |
| lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); |
| dget(lower_old_dentry); |
| dget(lower_new_dentry); |
| lower_dir_dentry = lock_parent(lower_new_dentry); |
| rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode, |
| lower_new_dentry); |
| if (rc || !lower_new_dentry->d_inode) |
| goto out_lock; |
| rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0); |
| if (rc) |
| goto out_lock; |
| fsstack_copy_attr_times(dir, lower_new_dentry->d_inode); |
| fsstack_copy_inode_size(dir, lower_new_dentry->d_inode); |
| old_dentry->d_inode->i_nlink = |
| ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink; |
| i_size_write(new_dentry->d_inode, file_size_save); |
| out_lock: |
| unlock_dir(lower_dir_dentry); |
| dput(lower_new_dentry); |
| dput(lower_old_dentry); |
| d_drop(lower_old_dentry); |
| d_drop(new_dentry); |
| d_drop(old_dentry); |
| return rc; |
| } |
| |
| static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) |
| { |
| int rc = 0; |
| struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); |
| struct dentry *lower_dir_dentry; |
| |
| lower_dir_dentry = lock_parent(lower_dentry); |
| rc = vfs_unlink(lower_dir_inode, lower_dentry); |
| if (rc) { |
| printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); |
| goto out_unlock; |
| } |
| fsstack_copy_attr_times(dir, lower_dir_inode); |
| dentry->d_inode->i_nlink = |
| ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink; |
| dentry->d_inode->i_ctime = dir->i_ctime; |
| d_drop(dentry); |
| out_unlock: |
| unlock_dir(lower_dir_dentry); |
| return rc; |
| } |
| |
| static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, |
| const char *symname) |
| { |
| int rc; |
| struct dentry *lower_dentry; |
| struct dentry *lower_dir_dentry; |
| umode_t mode; |
| char *encoded_symname; |
| int encoded_symlen; |
| struct ecryptfs_crypt_stat *crypt_stat = NULL; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| dget(lower_dentry); |
| lower_dir_dentry = lock_parent(lower_dentry); |
| mode = S_IALLUGO; |
| encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname, |
| strlen(symname), |
| &encoded_symname); |
| if (encoded_symlen < 0) { |
| rc = encoded_symlen; |
| goto out_lock; |
| } |
| rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry, |
| encoded_symname, mode); |
| kfree(encoded_symname); |
| if (rc || !lower_dentry->d_inode) |
| goto out_lock; |
| rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); |
| if (rc) |
| goto out_lock; |
| fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); |
| fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); |
| out_lock: |
| unlock_dir(lower_dir_dentry); |
| dput(lower_dentry); |
| if (!dentry->d_inode) |
| d_drop(dentry); |
| return rc; |
| } |
| |
| static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
| { |
| int rc; |
| struct dentry *lower_dentry; |
| struct dentry *lower_dir_dentry; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| lower_dir_dentry = lock_parent(lower_dentry); |
| rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode); |
| if (rc || !lower_dentry->d_inode) |
| goto out; |
| rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); |
| if (rc) |
| goto out; |
| fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); |
| fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); |
| dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; |
| out: |
| unlock_dir(lower_dir_dentry); |
| if (!dentry->d_inode) |
| d_drop(dentry); |
| return rc; |
| } |
| |
| static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry) |
| { |
| struct dentry *lower_dentry; |
| struct dentry *lower_dir_dentry; |
| int rc; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| dget(dentry); |
| lower_dir_dentry = lock_parent(lower_dentry); |
| dget(lower_dentry); |
| rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry); |
| dput(lower_dentry); |
| if (!rc) |
| d_delete(lower_dentry); |
| fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); |
| dir->i_nlink = lower_dir_dentry->d_inode->i_nlink; |
| unlock_dir(lower_dir_dentry); |
| if (!rc) |
| d_drop(dentry); |
| dput(dentry); |
| return rc; |
| } |
| |
| static int |
| ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) |
| { |
| int rc; |
| struct dentry *lower_dentry; |
| struct dentry *lower_dir_dentry; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| lower_dir_dentry = lock_parent(lower_dentry); |
| rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev); |
| if (rc || !lower_dentry->d_inode) |
| goto out; |
| rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0); |
| if (rc) |
| goto out; |
| fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode); |
| fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode); |
| out: |
| unlock_dir(lower_dir_dentry); |
| if (!dentry->d_inode) |
| d_drop(dentry); |
| return rc; |
| } |
| |
| static int |
| ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, |
| struct inode *new_dir, struct dentry *new_dentry) |
| { |
| int rc; |
| struct dentry *lower_old_dentry; |
| struct dentry *lower_new_dentry; |
| struct dentry *lower_old_dir_dentry; |
| struct dentry *lower_new_dir_dentry; |
| |
| lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry); |
| lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry); |
| dget(lower_old_dentry); |
| dget(lower_new_dentry); |
| lower_old_dir_dentry = dget_parent(lower_old_dentry); |
| lower_new_dir_dentry = dget_parent(lower_new_dentry); |
| lock_rename(lower_old_dir_dentry, lower_new_dir_dentry); |
| rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry, |
| lower_new_dir_dentry->d_inode, lower_new_dentry); |
| if (rc) |
| goto out_lock; |
| fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL); |
| if (new_dir != old_dir) |
| fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL); |
| out_lock: |
| unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry); |
| dput(lower_new_dentry->d_parent); |
| dput(lower_old_dentry->d_parent); |
| dput(lower_new_dentry); |
| dput(lower_old_dentry); |
| return rc; |
| } |
| |
| static int |
| ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz) |
| { |
| int rc; |
| struct dentry *lower_dentry; |
| char *decoded_name; |
| char *lower_buf; |
| mm_segment_t old_fs; |
| struct ecryptfs_crypt_stat *crypt_stat; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| if (!lower_dentry->d_inode->i_op || |
| !lower_dentry->d_inode->i_op->readlink) { |
| rc = -EINVAL; |
| goto out; |
| } |
| /* Released in this function */ |
| lower_buf = kmalloc(bufsiz, GFP_KERNEL); |
| if (lower_buf == NULL) { |
| ecryptfs_printk(KERN_ERR, "Out of memory\n"); |
| rc = -ENOMEM; |
| goto out; |
| } |
| old_fs = get_fs(); |
| set_fs(get_ds()); |
| ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ " |
| "lower_dentry->d_name.name = [%s]\n", |
| lower_dentry->d_name.name); |
| rc = lower_dentry->d_inode->i_op->readlink(lower_dentry, |
| (char __user *)lower_buf, |
| bufsiz); |
| set_fs(old_fs); |
| if (rc >= 0) { |
| crypt_stat = NULL; |
| rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc, |
| &decoded_name); |
| if (rc == -ENOMEM) |
| goto out_free_lower_buf; |
| if (rc > 0) { |
| ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes " |
| "to userspace: [%*s]\n", rc, |
| decoded_name); |
| if (copy_to_user(buf, decoded_name, rc)) |
| rc = -EFAULT; |
| } |
| kfree(decoded_name); |
| fsstack_copy_attr_atime(dentry->d_inode, |
| lower_dentry->d_inode); |
| } |
| out_free_lower_buf: |
| kfree(lower_buf); |
| out: |
| return rc; |
| } |
| |
| static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd) |
| { |
| char *buf; |
| int len = PAGE_SIZE, rc; |
| mm_segment_t old_fs; |
| |
| /* Released in ecryptfs_put_link(); only release here on error */ |
| buf = kmalloc(len, GFP_KERNEL); |
| if (!buf) { |
| rc = -ENOMEM; |
| goto out; |
| } |
| old_fs = get_fs(); |
| set_fs(get_ds()); |
| ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ " |
| "dentry->d_name.name = [%s]\n", dentry->d_name.name); |
| rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len); |
| buf[rc] = '\0'; |
| set_fs(old_fs); |
| if (rc < 0) |
| goto out_free; |
| rc = 0; |
| nd_set_link(nd, buf); |
| goto out; |
| out_free: |
| kfree(buf); |
| out: |
| return ERR_PTR(rc); |
| } |
| |
| static void |
| ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr) |
| { |
| /* Free the char* */ |
| kfree(nd_get_link(nd)); |
| } |
| |
| /** |
| * upper_size_to_lower_size |
| * @crypt_stat: Crypt_stat associated with file |
| * @upper_size: Size of the upper file |
| * |
| * Calculate the required size of the lower file based on the |
| * specified size of the upper file. This calculation is based on the |
| * number of headers in the underlying file and the extent size. |
| * |
| * Returns Calculated size of the lower file. |
| */ |
| static loff_t |
| upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat, |
| loff_t upper_size) |
| { |
| loff_t lower_size; |
| |
| lower_size = crypt_stat->num_header_bytes_at_front; |
| if (upper_size != 0) { |
| loff_t num_extents; |
| |
| num_extents = upper_size >> crypt_stat->extent_shift; |
| if (upper_size & ~crypt_stat->extent_mask) |
| num_extents++; |
| lower_size += (num_extents * crypt_stat->extent_size); |
| } |
| return lower_size; |
| } |
| |
| /** |
| * ecryptfs_truncate |
| * @dentry: The ecryptfs layer dentry |
| * @new_length: The length to expand the file to |
| * |
| * Function to handle truncations modifying the size of the file. Note |
| * that the file sizes are interpolated. When expanding, we are simply |
| * writing strings of 0's out. When truncating, we need to modify the |
| * underlying file size according to the page index interpolations. |
| * |
| * Returns zero on success; non-zero otherwise |
| */ |
| int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) |
| { |
| int rc = 0; |
| struct inode *inode = dentry->d_inode; |
| struct dentry *lower_dentry; |
| struct file fake_ecryptfs_file; |
| struct ecryptfs_crypt_stat *crypt_stat; |
| loff_t i_size = i_size_read(inode); |
| loff_t lower_size_before_truncate; |
| loff_t lower_size_after_truncate; |
| |
| if (unlikely((new_length == i_size))) |
| goto out; |
| crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; |
| /* Set up a fake ecryptfs file, this is used to interface with |
| * the file in the underlying filesystem so that the |
| * truncation has an effect there as well. */ |
| memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file)); |
| fake_ecryptfs_file.f_path.dentry = dentry; |
| /* Released at out_free: label */ |
| ecryptfs_set_file_private(&fake_ecryptfs_file, |
| kmem_cache_alloc(ecryptfs_file_info_cache, |
| GFP_KERNEL)); |
| if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) { |
| rc = -ENOMEM; |
| goto out; |
| } |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| ecryptfs_set_file_lower( |
| &fake_ecryptfs_file, |
| ecryptfs_inode_to_private(dentry->d_inode)->lower_file); |
| /* Switch on growing or shrinking file */ |
| if (new_length > i_size) { |
| char zero[] = { 0x00 }; |
| |
| /* Write a single 0 at the last position of the file; |
| * this triggers code that will fill in 0's throughout |
| * the intermediate portion of the previous end of the |
| * file and the new and of the file */ |
| rc = ecryptfs_write(&fake_ecryptfs_file, zero, |
| (new_length - 1), 1); |
| } else { /* new_length < i_size_read(inode) */ |
| /* We're chopping off all the pages down do the page |
| * in which new_length is located. Fill in the end of |
| * that page from (new_length & ~PAGE_CACHE_MASK) to |
| * PAGE_CACHE_SIZE with zeros. */ |
| size_t num_zeros = (PAGE_CACHE_SIZE |
| - (new_length & ~PAGE_CACHE_MASK)); |
| |
| if (num_zeros) { |
| char *zeros_virt; |
| |
| zeros_virt = kzalloc(num_zeros, GFP_KERNEL); |
| if (!zeros_virt) { |
| rc = -ENOMEM; |
| goto out_free; |
| } |
| rc = ecryptfs_write(&fake_ecryptfs_file, zeros_virt, |
| new_length, num_zeros); |
| kfree(zeros_virt); |
| if (rc) { |
| printk(KERN_ERR "Error attempting to zero out " |
| "the remainder of the end page on " |
| "reducing truncate; rc = [%d]\n", rc); |
| goto out_free; |
| } |
| } |
| vmtruncate(inode, new_length); |
| rc = ecryptfs_write_inode_size_to_metadata(inode); |
| if (rc) { |
| printk(KERN_ERR "Problem with " |
| "ecryptfs_write_inode_size_to_metadata; " |
| "rc = [%d]\n", rc); |
| goto out_free; |
| } |
| /* We are reducing the size of the ecryptfs file, and need to |
| * know if we need to reduce the size of the lower file. */ |
| lower_size_before_truncate = |
| upper_size_to_lower_size(crypt_stat, i_size); |
| lower_size_after_truncate = |
| upper_size_to_lower_size(crypt_stat, new_length); |
| if (lower_size_after_truncate < lower_size_before_truncate) |
| vmtruncate(lower_dentry->d_inode, |
| lower_size_after_truncate); |
| } |
| out_free: |
| if (ecryptfs_file_to_private(&fake_ecryptfs_file)) |
| kmem_cache_free(ecryptfs_file_info_cache, |
| ecryptfs_file_to_private(&fake_ecryptfs_file)); |
| out: |
| return rc; |
| } |
| |
| static int |
| ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd) |
| { |
| int rc; |
| |
| if (nd) { |
| struct vfsmount *vfsmnt_save = nd->path.mnt; |
| struct dentry *dentry_save = nd->path.dentry; |
| |
| nd->path.mnt = ecryptfs_dentry_to_lower_mnt(nd->path.dentry); |
| nd->path.dentry = ecryptfs_dentry_to_lower(nd->path.dentry); |
| rc = permission(ecryptfs_inode_to_lower(inode), mask, nd); |
| nd->path.mnt = vfsmnt_save; |
| nd->path.dentry = dentry_save; |
| } else |
| rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL); |
| return rc; |
| } |
| |
| /** |
| * ecryptfs_setattr |
| * @dentry: dentry handle to the inode to modify |
| * @ia: Structure with flags of what to change and values |
| * |
| * Updates the metadata of an inode. If the update is to the size |
| * i.e. truncation, then ecryptfs_truncate will handle the size modification |
| * of both the ecryptfs inode and the lower inode. |
| * |
| * All other metadata changes will be passed right to the lower filesystem, |
| * and we will just update our inode to look like the lower. |
| */ |
| static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) |
| { |
| int rc = 0; |
| struct dentry *lower_dentry; |
| struct inode *inode; |
| struct inode *lower_inode; |
| struct ecryptfs_crypt_stat *crypt_stat; |
| |
| crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat; |
| if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) |
| ecryptfs_init_crypt_stat(crypt_stat); |
| inode = dentry->d_inode; |
| lower_inode = ecryptfs_inode_to_lower(inode); |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| mutex_lock(&crypt_stat->cs_mutex); |
| if (S_ISDIR(dentry->d_inode->i_mode)) |
| crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
| else if (S_ISREG(dentry->d_inode->i_mode) |
| && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) |
| || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) { |
| struct ecryptfs_mount_crypt_stat *mount_crypt_stat; |
| |
| mount_crypt_stat = &ecryptfs_superblock_to_private( |
| dentry->d_sb)->mount_crypt_stat; |
| rc = ecryptfs_read_metadata(dentry); |
| if (rc) { |
| if (!(mount_crypt_stat->flags |
| & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { |
| rc = -EIO; |
| printk(KERN_WARNING "Either the lower file " |
| "is not in a valid eCryptfs format, " |
| "or the key could not be retrieved. " |
| "Plaintext passthrough mode is not " |
| "enabled; returning -EIO\n"); |
| mutex_unlock(&crypt_stat->cs_mutex); |
| goto out; |
| } |
| rc = 0; |
| crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
| mutex_unlock(&crypt_stat->cs_mutex); |
| goto out; |
| } |
| } |
| mutex_unlock(&crypt_stat->cs_mutex); |
| if (ia->ia_valid & ATTR_SIZE) { |
| ecryptfs_printk(KERN_DEBUG, |
| "ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n", |
| ia->ia_valid, ATTR_SIZE); |
| rc = ecryptfs_truncate(dentry, ia->ia_size); |
| /* ecryptfs_truncate handles resizing of the lower file */ |
| ia->ia_valid &= ~ATTR_SIZE; |
| ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n", |
| ia->ia_valid); |
| if (rc < 0) |
| goto out; |
| } |
| |
| /* |
| * mode change is for clearing setuid/setgid bits. Allow lower fs |
| * to interpret this in its own way. |
| */ |
| if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) |
| ia->ia_valid &= ~ATTR_MODE; |
| |
| mutex_lock(&lower_dentry->d_inode->i_mutex); |
| rc = notify_change(lower_dentry, ia); |
| mutex_unlock(&lower_dentry->d_inode->i_mutex); |
| out: |
| fsstack_copy_attr_all(inode, lower_inode, NULL); |
| return rc; |
| } |
| |
| int |
| ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
| size_t size, int flags) |
| { |
| int rc = 0; |
| struct dentry *lower_dentry; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| if (!lower_dentry->d_inode->i_op->setxattr) { |
| rc = -ENOSYS; |
| goto out; |
| } |
| mutex_lock(&lower_dentry->d_inode->i_mutex); |
| rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value, |
| size, flags); |
| mutex_unlock(&lower_dentry->d_inode->i_mutex); |
| out: |
| return rc; |
| } |
| |
| ssize_t |
| ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name, |
| void *value, size_t size) |
| { |
| int rc = 0; |
| |
| if (!lower_dentry->d_inode->i_op->getxattr) { |
| rc = -ENOSYS; |
| goto out; |
| } |
| mutex_lock(&lower_dentry->d_inode->i_mutex); |
| rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value, |
| size); |
| mutex_unlock(&lower_dentry->d_inode->i_mutex); |
| out: |
| return rc; |
| } |
| |
| static ssize_t |
| ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value, |
| size_t size) |
| { |
| return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name, |
| value, size); |
| } |
| |
| static ssize_t |
| ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size) |
| { |
| int rc = 0; |
| struct dentry *lower_dentry; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| if (!lower_dentry->d_inode->i_op->listxattr) { |
| rc = -ENOSYS; |
| goto out; |
| } |
| mutex_lock(&lower_dentry->d_inode->i_mutex); |
| rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size); |
| mutex_unlock(&lower_dentry->d_inode->i_mutex); |
| out: |
| return rc; |
| } |
| |
| static int ecryptfs_removexattr(struct dentry *dentry, const char *name) |
| { |
| int rc = 0; |
| struct dentry *lower_dentry; |
| |
| lower_dentry = ecryptfs_dentry_to_lower(dentry); |
| if (!lower_dentry->d_inode->i_op->removexattr) { |
| rc = -ENOSYS; |
| goto out; |
| } |
| mutex_lock(&lower_dentry->d_inode->i_mutex); |
| rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name); |
| mutex_unlock(&lower_dentry->d_inode->i_mutex); |
| out: |
| return rc; |
| } |
| |
| int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode) |
| { |
| if ((ecryptfs_inode_to_lower(inode) |
| == (struct inode *)candidate_lower_inode)) |
| return 1; |
| else |
| return 0; |
| } |
| |
| int ecryptfs_inode_set(struct inode *inode, void *lower_inode) |
| { |
| ecryptfs_init_inode(inode, (struct inode *)lower_inode); |
| return 0; |
| } |
| |
| const struct inode_operations ecryptfs_symlink_iops = { |
| .readlink = ecryptfs_readlink, |
| .follow_link = ecryptfs_follow_link, |
| .put_link = ecryptfs_put_link, |
| .permission = ecryptfs_permission, |
| .setattr = ecryptfs_setattr, |
| .setxattr = ecryptfs_setxattr, |
| .getxattr = ecryptfs_getxattr, |
| .listxattr = ecryptfs_listxattr, |
| .removexattr = ecryptfs_removexattr |
| }; |
| |
| const struct inode_operations ecryptfs_dir_iops = { |
| .create = ecryptfs_create, |
| .lookup = ecryptfs_lookup, |
| .link = ecryptfs_link, |
| .unlink = ecryptfs_unlink, |
| .symlink = ecryptfs_symlink, |
| .mkdir = ecryptfs_mkdir, |
| .rmdir = ecryptfs_rmdir, |
| .mknod = ecryptfs_mknod, |
| .rename = ecryptfs_rename, |
| .permission = ecryptfs_permission, |
| .setattr = ecryptfs_setattr, |
| .setxattr = ecryptfs_setxattr, |
| .getxattr = ecryptfs_getxattr, |
| .listxattr = ecryptfs_listxattr, |
| .removexattr = ecryptfs_removexattr |
| }; |
| |
| const struct inode_operations ecryptfs_main_iops = { |
| .permission = ecryptfs_permission, |
| .setattr = ecryptfs_setattr, |
| .setxattr = ecryptfs_setxattr, |
| .getxattr = ecryptfs_getxattr, |
| .listxattr = ecryptfs_listxattr, |
| .removexattr = ecryptfs_removexattr |
| }; |