/**
* 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 <linux/slab.h>
#include <linux/xattr.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
* @dentry: New file's dentry
* @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;
unsigned int flags_save;
int rc;
if (nd) {
dentry_save = nd->path.dentry;
vfsmount_save = nd->path.mnt;
flags_save = nd->flags;
nd->path.dentry = lower_dentry;
nd->path.mnt = lower_mnt;
nd->flags &= ~LOOKUP_OPEN;
}
rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
if (nd) {
nd->path.dentry = dentry_save;
nd->path.mnt = vfsmount_save;
nd->flags = flags_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;
}
/**
* 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;
}
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_get_lower_file(ecryptfs_dentry);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the lower file for the dentry with name "
"[%s]; rc = [%d]\n", __func__,
ecryptfs_dentry->d_name.name, rc);
goto out;
}
rc = ecryptfs_write_metadata(ecryptfs_dentry);
if (rc)
printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
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() */
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_and_interpose_lower - Perform a lookup
*/
int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
struct dentry *lower_dentry,
struct inode *ecryptfs_dir_inode)
{
struct dentry *lower_dir_dentry;
struct vfsmount *lower_mnt;
struct inode *lower_inode;
struct ecryptfs_crypt_stat *crypt_stat;
char *page_virt = NULL;
int put_lower = 0, rc = 0;
lower_dir_dentry = lower_dentry->d_parent;
lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
ecryptfs_dentry->d_parent));
lower_inode = lower_dentry->d_inode;
fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
BUG_ON(!lower_dentry->d_count);
ecryptfs_set_dentry_private(ecryptfs_dentry,
kmem_cache_alloc(ecryptfs_dentry_info_cache,
GFP_KERNEL));
if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
rc = -ENOMEM;
printk(KERN_ERR "%s: Out of memory whilst attempting "
"to allocate ecryptfs_dentry_info struct\n",
__func__);
goto out_put;
}
ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
if (!lower_dentry->d_inode) {
/* We want to add because we couldn't find in lower */
d_add(ecryptfs_dentry, NULL);
goto out;
}
rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
ecryptfs_dir_inode->i_sb,
ECRYPTFS_INTERPOSE_FLAG_D_ADD);
if (rc) {
printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
__func__, rc);
goto out;
}
if (S_ISDIR(lower_inode->i_mode))
goto out;
if (S_ISLNK(lower_inode->i_mode))
goto out;
if (special_file(lower_inode->i_mode))
goto out;
/* Released in this function */
page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
if (!page_virt) {
printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
__func__);
rc = -ENOMEM;
goto out;
}
rc = ecryptfs_get_lower_file(ecryptfs_dentry);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the lower file for the dentry with name "
"[%s]; rc = [%d]\n", __func__,
ecryptfs_dentry->d_name.name, rc);
goto out_free_kmem;
}
put_lower = 1;
crypt_stat = &ecryptfs_inode_to_private(
ecryptfs_dentry->d_inode)->crypt_stat;
/* TODO: lock for crypt_stat comparison */
if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
ecryptfs_set_default_sizes(crypt_stat);
rc = ecryptfs_read_and_validate_header_region(page_virt,
ecryptfs_dentry->d_inode);
if (rc) {
memset(page_virt, 0, PAGE_CACHE_SIZE);
rc = ecryptfs_read_and_validate_xattr_region(page_virt,
ecryptfs_dentry);
if (rc) {
rc = 0;
goto out_free_kmem;
}
crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
}
ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
out_free_kmem:
kmem_cache_free(ecryptfs_header_cache_2, page_virt);
goto out;
out_put:
dput(lower_dentry);
mntput(lower_mnt);
d_drop(ecryptfs_dentry);
out:
if (put_lower)
ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
return rc;
}
/**
* ecryptfs_lookup
* @ecryptfs_dir_inode: The eCryptfs directory inode
* @ecryptfs_dentry: The eCryptfs dentry that we are looking up
* @ecryptfs_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 *ecryptfs_dir_inode,
struct dentry *ecryptfs_dentry,
struct nameidata *ecryptfs_nd)
{
char *encrypted_and_encoded_name = NULL;
size_t encrypted_and_encoded_name_size;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
struct dentry *lower_dir_dentry, *lower_dentry;
int rc = 0;
if ((ecryptfs_dentry->d_name.len == 1
&& !strcmp(ecryptfs_dentry->d_name.name, "."))
|| (ecryptfs_dentry->d_name.len == 2
&& !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
goto out_d_drop;
}
lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
lower_dir_dentry,
ecryptfs_dentry->d_name.len);
mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
if (IS_ERR(lower_dentry)) {
rc = PTR_ERR(lower_dentry);
ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
"[%d] on lower_dentry = [%s]\n", __func__, rc,
encrypted_and_encoded_name);
goto out_d_drop;
}
if (lower_dentry->d_inode)
goto lookup_and_interpose;
mount_crypt_stat = &ecryptfs_superblock_to_private(
ecryptfs_dentry->d_sb)->mount_crypt_stat;
if (!(mount_crypt_stat
&& (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
goto lookup_and_interpose;
dput(lower_dentry);
rc = ecryptfs_encrypt_and_encode_filename(
&encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
ecryptfs_dentry->d_name.len);
if (rc) {
printk(KERN_ERR "%s: Error attempting to encrypt and encode "
"filename; rc = [%d]\n", __func__, rc);
goto out_d_drop;
}
mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
lower_dentry = lookup_one_len(encrypted_and_encoded_name,
lower_dir_dentry,
encrypted_and_encoded_name_size);
mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
if (IS_ERR(lower_dentry)) {
rc = PTR_ERR(lower_dentry);
ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
"[%d] on lower_dentry = [%s]\n", __func__, rc,
encrypted_and_encoded_name);
goto out_d_drop;
}
lookup_and_interpose:
rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
ecryptfs_dir_inode);
goto out;
out_d_drop:
d_drop(ecryptfs_dentry);
out:
kfree(encrypted_and_encoded_name);
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_dir_dentry->d_inode);
fsstack_copy_inode_size(dir, lower_dir_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);
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;
dget(lower_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);
dput(lower_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;
char *encoded_symname;
size_t encoded_symlen;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
lower_dentry = ecryptfs_dentry_to_lower(dentry);
dget(lower_dentry);
lower_dir_dentry = lock_parent(lower_dentry);
mount_crypt_stat = &ecryptfs_superblock_to_private(
dir->i_sb)->mount_crypt_stat;
rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
&encoded_symlen,
NULL,
mount_crypt_stat, symname,
strlen(symname));
if (rc)
goto out_lock;
rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
encoded_symname);
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 && dentry->d_inode)
clear_nlink(dentry->d_inode);
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;
struct dentry *trap = NULL;
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);
trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
/* source should not be ancestor of target */
if (trap == lower_old_dentry) {
rc = -EINVAL;
goto out_lock;
}
/* target should not be ancestor of source */
if (trap == lower_new_dentry) {
rc = -ENOTEMPTY;
goto out_lock;
}
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);
if (new_dir != old_dir)
fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
out_lock:
unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
dput(lower_new_dir_dentry);
dput(lower_old_dir_dentry);
dput(lower_new_dentry);
dput(lower_old_dentry);
return rc;
}
static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
size_t *bufsiz)
{
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
char *lower_buf;
size_t lower_bufsiz = PATH_MAX;
mm_segment_t old_fs;
int rc;
lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
if (!lower_buf) {
rc = -ENOMEM;
goto out;
}
old_fs = get_fs();
set_fs(get_ds());
rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
(char __user *)lower_buf,
lower_bufsiz);
set_fs(old_fs);
if (rc < 0)
goto out;
lower_bufsiz = rc;
rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
lower_buf, lower_bufsiz);
out:
kfree(lower_buf);
return rc;
}
static int
ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
{
char *kbuf;
size_t kbufsiz, copied;
int rc;
rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
if (rc)
goto out;
copied = min_t(size_t, bufsiz, kbufsiz);
rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
kfree(kbuf);
fsstack_copy_attr_atime(dentry->d_inode,
ecryptfs_dentry_to_lower(dentry)->d_inode);
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) {
buf = ERR_PTR(-ENOMEM);
goto out;
}
old_fs = get_fs();
set_fs(get_ds());
rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
set_fs(old_fs);
if (rc < 0) {
kfree(buf);
buf = ERR_PTR(rc);
} else
buf[rc] = '\0';
out:
nd_set_link(nd, buf);
return NULL;
}
static void
ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
{
char *buf = nd_get_link(nd);
if (!IS_ERR(buf)) {
/* Free the char* */
kfree(buf);
}
}
/**
* 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 = ecryptfs_lower_header_size(crypt_stat);
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;
}
/**
* truncate_upper
* @dentry: The ecryptfs layer dentry
* @ia: Address of the ecryptfs inode's attributes
* @lower_ia: Address of the lower inode's attributes
*
* 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 truncate the upper
* inode and update the lower_ia according to the page index
* interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
* the caller must use lower_ia in a call to notify_change() to perform
* the truncation of the lower inode.
*
* Returns zero on success; non-zero otherwise
*/
static int truncate_upper(struct dentry *dentry, struct iattr *ia,
struct iattr *lower_ia)
{
int rc = 0;
struct inode *inode = dentry->d_inode;
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((ia->ia_size == i_size))) {
lower_ia->ia_valid &= ~ATTR_SIZE;
return 0;
}
rc = ecryptfs_get_lower_file(dentry);
if (rc)
return rc;
crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
/* Switch on growing or shrinking file */
if (ia->ia_size > i_size) {
char zero[] = { 0x00 };
lower_ia->ia_valid &= ~ATTR_SIZE;
/* 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(inode, zero,
(ia->ia_size - 1), 1);
} else { /* ia->ia_size < i_size_read(inode) */
/* We're chopping off all the pages down to the page
* in which ia->ia_size is located. Fill in the end of
* that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
* PAGE_CACHE_SIZE with zeros. */
size_t num_zeros = (PAGE_CACHE_SIZE
- (ia->ia_size & ~PAGE_CACHE_MASK));
/*
* XXX(truncate) this should really happen at the begginning
* of ->setattr. But the code is too messy to that as part
* of a larger patch. ecryptfs is also totally missing out
* on the inode_change_ok check at the beginning of
* ->setattr while would include this.
*/
rc = inode_newsize_ok(inode, ia->ia_size);
if (rc)
goto out;
if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
truncate_setsize(inode, ia->ia_size);
lower_ia->ia_size = ia->ia_size;
lower_ia->ia_valid |= ATTR_SIZE;
goto out;
}
if (num_zeros) {
char *zeros_virt;
zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
if (!zeros_virt) {
rc = -ENOMEM;
goto out;
}
rc = ecryptfs_write(inode, zeros_virt,
ia->ia_size, 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;
}
}
truncate_setsize(inode, ia->ia_size);
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;
}
/* 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, ia->ia_size);
if (lower_size_after_truncate < lower_size_before_truncate) {
lower_ia->ia_size = lower_size_after_truncate;
lower_ia->ia_valid |= ATTR_SIZE;
} else
lower_ia->ia_valid &= ~ATTR_SIZE;
}
out:
ecryptfs_put_lower_file(inode);
return rc;
}
/**
* ecryptfs_truncate
* @dentry: The ecryptfs layer dentry
* @new_length: The length to expand the file to
*
* Simple function that handles the truncation of an eCryptfs inode and
* its corresponding lower inode.
*
* Returns zero on success; non-zero otherwise
*/
int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
{
struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
struct iattr lower_ia = { .ia_valid = 0 };
int rc;
rc = truncate_upper(dentry, &ia, &lower_ia);
if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
mutex_lock(&lower_dentry->d_inode->i_mutex);
rc = notify_change(lower_dentry, &lower_ia);
mutex_unlock(&lower_dentry->d_inode->i_mutex);
}
return rc;
}
static int
ecryptfs_permission(struct inode *inode, int mask, unsigned int flags)
{
if (flags & IPERM_FLAG_RCU)
return -ECHILD;
return inode_permission(ecryptfs_inode_to_lower(inode), mask);
}
/**
* 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 iattr lower_ia;
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_get_lower_file(dentry);
if (rc) {
mutex_unlock(&crypt_stat->cs_mutex);
goto out;
}
rc = ecryptfs_read_metadata(dentry);
ecryptfs_put_lower_file(inode);
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_I_SIZE_INITIALIZED
| ECRYPTFS_ENCRYPTED);
}
}
mutex_unlock(&crypt_stat->cs_mutex);
if (S_ISREG(inode->i_mode)) {
rc = filemap_write_and_wait(inode->i_mapping);
if (rc)
goto out;
fsstack_copy_attr_all(inode, lower_inode);
}
memcpy(&lower_ia, ia, sizeof(lower_ia));
if (ia->ia_valid & ATTR_FILE)
lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
if (ia->ia_valid & ATTR_SIZE) {
rc = truncate_upper(dentry, ia, &lower_ia);
if (rc < 0)
goto out;
}
/*
* mode change is for clearing setuid/setgid bits. Allow lower fs
* to interpret this in its own way.
*/
if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
lower_ia.ia_valid &= ~ATTR_MODE;
mutex_lock(&lower_dentry->d_inode->i_mutex);
rc = notify_change(lower_dentry, &lower_ia);
mutex_unlock(&lower_dentry->d_inode->i_mutex);
out:
fsstack_copy_attr_all(inode, lower_inode);
return rc;
}
int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
int rc = 0;
mount_crypt_stat = &ecryptfs_superblock_to_private(
dentry->d_sb)->mount_crypt_stat;
generic_fillattr(dentry->d_inode, stat);
if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
char *target;
size_t targetsiz;
rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
if (!rc) {
kfree(target);
stat->size = targetsiz;
}
}
return rc;
}
int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
struct kstat lower_stat;
int rc;
rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
ecryptfs_dentry_to_lower(dentry), &lower_stat);
if (!rc) {
fsstack_copy_attr_all(dentry->d_inode,
ecryptfs_inode_to_lower(dentry->d_inode));
generic_fillattr(dentry->d_inode, stat);
stat->blocks = lower_stat.blocks;
}
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 = -EOPNOTSUPP;
goto out;
}
rc = vfs_setxattr(lower_dentry, name, value, size, flags);
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 = -EOPNOTSUPP;
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 = -EOPNOTSUPP;
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 = -EOPNOTSUPP;
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,
.getattr = ecryptfs_getattr_link,
.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,
.getattr = ecryptfs_getattr,
.setxattr = ecryptfs_setxattr,
.getxattr = ecryptfs_getxattr,
.listxattr = ecryptfs_listxattr,
.removexattr = ecryptfs_removexattr
};