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a261a03904
linux-next/fs/ecryptfs/inode.c
Tyler Hicks a261a03904 eCryptfs: Check inode changes in setattr 
Most filesystems call inode_change_ok() very early in ->setattr(), but
eCryptfs didn't call it at all. It allowed the lower filesystem to make
the call in its ->setattr() function. Then, eCryptfs would copy the
appropriate inode attributes from the lower inode to the eCryptfs inode.

This patch changes that and actually calls inode_change_ok() on the
eCryptfs inode, fairly early in ecryptfs_setattr(). Ideally, the call
would happen earlier in ecryptfs_setattr(), but there are some possible
inode initialization steps that must happen first.

Since the call was already being made on the lower inode, the change in
functionality should be minimal, except for the case of a file extending
truncate call. In that case, inode_newsize_ok() was never being
called on the eCryptfs inode. Rather than inode_newsize_ok() catching
maximum file size errors early on, eCryptfs would encrypt zeroed pages
and write them to the lower filesystem until the lower filesystem's
write path caught the error in generic_write_checks(). This patch
introduces a new function, called ecryptfs_inode_newsize_ok(), which
checks if the new lower file size is within the appropriate limits when
the truncate operation will be growing the lower file.

In summary this change prevents eCryptfs truncate operations (and the
resulting page encryptions), which would exceed the lower filesystem
limits or FSIZE rlimits, from ever starting.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Li Wang <liwang@nudt.edu.cn>
Cc: <stable@vger.kernel.org>
2012-01-25 14:43:41 -06:00

1193 lines
34 KiB
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/**
* 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);
}
static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
{
if (ecryptfs_inode_to_lower(inode) == (struct inode *)lower_inode)
return 1;
return 0;
}
static int ecryptfs_inode_set(struct inode *inode, void *opaque)
{
struct inode *lower_inode = opaque;
ecryptfs_set_inode_lower(inode, lower_inode);
fsstack_copy_attr_all(inode, lower_inode);
/* i_size will be overwritten for encrypted regular files */
fsstack_copy_inode_size(inode, lower_inode);
inode->i_ino = lower_inode->i_ino;
inode->i_version++;
inode->i_mapping->a_ops = &ecryptfs_aops;
inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
if (S_ISLNK(inode->i_mode))
inode->i_op = &ecryptfs_symlink_iops;
else if (S_ISDIR(inode->i_mode))
inode->i_op = &ecryptfs_dir_iops;
else
inode->i_op = &ecryptfs_main_iops;
if (S_ISDIR(inode->i_mode))
inode->i_fop = &ecryptfs_dir_fops;
else if (special_file(inode->i_mode))
init_special_inode(inode, inode->i_mode, inode->i_rdev);
else
inode->i_fop = &ecryptfs_main_fops;
return 0;
}
static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
struct super_block *sb)
{
struct inode *inode;
if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
return ERR_PTR(-EXDEV);
if (!igrab(lower_inode))
return ERR_PTR(-ESTALE);
inode = iget5_locked(sb, (unsigned long)lower_inode,
ecryptfs_inode_test, ecryptfs_inode_set,
lower_inode);
if (!inode) {
iput(lower_inode);
return ERR_PTR(-EACCES);
}
if (!(inode->i_state & I_NEW))
iput(lower_inode);
return inode;
}
struct inode *ecryptfs_get_inode(struct inode *lower_inode,
struct super_block *sb)
{
struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
if (!IS_ERR(inode) && (inode->i_state & I_NEW))
unlock_new_inode(inode);
return inode;
}
/**
* ecryptfs_interpose
* @lower_dentry: Existing dentry in the lower filesystem
* @dentry: ecryptfs' dentry
* @sb: ecryptfs's super_block
*
* Interposes upper and lower dentries.
*
* Returns zero on success; non-zero otherwise
*/
static int ecryptfs_interpose(struct dentry *lower_dentry,
struct dentry *dentry, struct super_block *sb)
{
struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb);
if (IS_ERR(inode))
return PTR_ERR(inode);
d_instantiate(dentry, inode);
return 0;
}
/**
* 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 the new eCryptfs inode on success; an ERR_PTR on error condition
*/
static struct inode *
ecryptfs_do_create(struct inode *directory_inode,
struct dentry *ecryptfs_dentry, umode_t mode)
{
int rc;
struct dentry *lower_dentry;
struct dentry *lower_dir_dentry;
struct inode *inode;
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");
inode = ERR_CAST(lower_dir_dentry);
goto out;
}
rc = vfs_create(lower_dir_dentry->d_inode, lower_dentry, mode, NULL);
if (rc) {
printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
"rc = [%d]\n", __func__, rc);
inode = ERR_PTR(rc);
goto out_lock;
}
inode = __ecryptfs_get_inode(lower_dentry->d_inode,
directory_inode->i_sb);
if (IS_ERR(inode))
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 inode;
}
/**
* 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 inode *ecryptfs_inode)
{
struct ecryptfs_crypt_stat *crypt_stat =
&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
int rc = 0;
if (S_ISDIR(ecryptfs_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_inode);
if (rc) {
ecryptfs_printk(KERN_ERR, "Error creating new file "
"context; rc = [%d]\n", rc);
goto out;
}
rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
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, ecryptfs_inode);
if (rc)
printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
ecryptfs_put_lower_file(ecryptfs_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,
umode_t mode, struct nameidata *nd)
{
struct inode *ecryptfs_inode;
int rc;
ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
mode);
if (unlikely(IS_ERR(ecryptfs_inode))) {
ecryptfs_printk(KERN_WARNING, "Failed to create file in"
"lower filesystem\n");
rc = PTR_ERR(ecryptfs_inode);
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, ecryptfs_inode);
if (rc) {
drop_nlink(ecryptfs_inode);
unlock_new_inode(ecryptfs_inode);
iput(ecryptfs_inode);
goto out;
}
d_instantiate(ecryptfs_dentry, ecryptfs_inode);
unlock_new_inode(ecryptfs_inode);
out:
return rc;
}
static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
{
struct ecryptfs_crypt_stat *crypt_stat;
int rc;
rc = ecryptfs_get_lower_file(dentry, inode);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the lower file for the dentry with name "
"[%s]; rc = [%d]\n", __func__,
dentry->d_name.name, rc);
return rc;
}
crypt_stat = &ecryptfs_inode_to_private(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(inode);
ecryptfs_put_lower_file(inode);
if (rc) {
rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
if (!rc)
crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
}
/* Must return 0 to allow non-eCryptfs files to be looked up, too */
return 0;
}
/**
* ecryptfs_lookup_interpose - Dentry interposition for a lookup
*/
static int ecryptfs_lookup_interpose(struct dentry *dentry,
struct dentry *lower_dentry,
struct inode *dir_inode)
{
struct inode *inode, *lower_inode = lower_dentry->d_inode;
struct ecryptfs_dentry_info *dentry_info;
struct vfsmount *lower_mnt;
int rc = 0;
lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
BUG_ON(!lower_dentry->d_count);
dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
ecryptfs_set_dentry_private(dentry, dentry_info);
if (!dentry_info) {
printk(KERN_ERR "%s: Out of memory whilst attempting "
"to allocate ecryptfs_dentry_info struct\n",
__func__);
dput(lower_dentry);
mntput(lower_mnt);
d_drop(dentry);
return -ENOMEM;
}
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);
return 0;
}
inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
if (IS_ERR(inode)) {
printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
__func__, PTR_ERR(inode));
return PTR_ERR(inode);
}
if (S_ISREG(inode->i_mode)) {
rc = ecryptfs_i_size_read(dentry, inode);
if (rc) {
make_bad_inode(inode);
return rc;
}
}
if (inode->i_state & I_NEW)
unlock_new_inode(inode);
d_add(dentry, 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 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 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;
}
interpose:
rc = ecryptfs_lookup_interpose(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);
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);
set_nlink(old_dentry->d_inode,
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);
set_nlink(dentry->d_inode,
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);
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, umode_t 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);
if (rc)
goto out;
fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
set_nlink(dir, 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);
set_nlink(dir, 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, umode_t 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);
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, inode);
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));
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;
}
static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
{
struct ecryptfs_crypt_stat *crypt_stat;
loff_t lower_oldsize, lower_newsize;
crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
lower_oldsize = upper_size_to_lower_size(crypt_stat,
i_size_read(inode));
lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
if (lower_newsize > lower_oldsize) {
/*
* The eCryptfs inode and the new *lower* size are mixed here
* because we may not have the lower i_mutex held and/or it may
* not be appropriate to call inode_newsize_ok() with inodes
* from other filesystems.
*/
return inode_newsize_ok(inode, lower_newsize);
}
return 0;
}
/**
* 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 = ecryptfs_inode_newsize_ok(dentry->d_inode, new_length);
if (rc)
return 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)
{
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, inode);
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);
rc = inode_change_ok(inode, ia);
if (rc)
goto out;
if (ia->ia_valid & ATTR_SIZE) {
rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
if (rc)
goto out;
}
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;
}
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
};
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