/**
* 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 <mhalcrow@us.ibm.com>
* Michael C. Thompson <mcthomps@us.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <linux/file.h>
#include <linux/poll.h>
#include <linux/mount.h>
#include <linux/pagemap.h>
#include <linux/security.h>
#include <linux/smp_lock.h>
#include <linux/compat.h>
#include <linux/fs_stack.h>
#include "ecryptfs_kernel.h"
/**
* ecryptfs_llseek
* @file: File we are seeking in
* @offset: The offset to seek to
* @origin: 2 - offset from i_size; 1 - offset from f_pos
*
* Returns the position we have seeked to, or negative on error
*/
static loff_t ecryptfs_llseek(struct file *file, loff_t offset, int origin)
{
loff_t rv;
loff_t new_end_pos;
int rc;
int expanding_file = 0;
struct inode *inode = file->f_mapping->host;
/* If our offset is past the end of our file, we're going to
* need to grow it so we have a valid length of 0's */
new_end_pos = offset;
switch (origin) {
case 2:
new_end_pos += i_size_read(inode);
expanding_file = 1;
break;
case 1:
new_end_pos += file->f_pos;
if (new_end_pos > i_size_read(inode)) {
ecryptfs_printk(KERN_DEBUG, "new_end_pos(=[0x%.16x]) "
"> i_size_read(inode)(=[0x%.16x])\n",
new_end_pos, i_size_read(inode));
expanding_file = 1;
}
break;
default:
if (new_end_pos > i_size_read(inode)) {
ecryptfs_printk(KERN_DEBUG, "new_end_pos(=[0x%.16x]) "
"> i_size_read(inode)(=[0x%.16x])\n",
new_end_pos, i_size_read(inode));
expanding_file = 1;
}
}
ecryptfs_printk(KERN_DEBUG, "new_end_pos = [0x%.16x]\n", new_end_pos);
if (expanding_file) {
rc = ecryptfs_truncate(file->f_path.dentry, new_end_pos);
if (rc) {
rv = rc;
ecryptfs_printk(KERN_ERR, "Error on attempt to "
"truncate to (higher) offset [0x%.16x];"
" rc = [%d]\n", new_end_pos, rc);
goto out;
}
}
rv = generic_file_llseek(file, offset, origin);
out:
return rv;
}
/**
* ecryptfs_read_update_atime
*
* generic_file_read updates the atime of upper layer inode. But, it
* doesn't give us a chance to update the atime of the lower layer
* inode. This function is a wrapper to generic_file_read. It
* updates the atime of the lower level inode if generic_file_read
* returns without any errors. This is to be used only for file reads.
* The function to be used for directory reads is ecryptfs_read.
*/
static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
int rc;
struct dentry *lower_dentry;
struct vfsmount *lower_vfsmount;
struct file *file = iocb->ki_filp;
rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
/*
* Even though this is a async interface, we need to wait
* for IO to finish to update atime
*/
if (-EIOCBQUEUED == rc)
rc = wait_on_sync_kiocb(iocb);
if (rc >= 0) {
lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
touch_atime(lower_vfsmount, lower_dentry);
}
return rc;
}
struct ecryptfs_getdents_callback {
void *dirent;
struct dentry *dentry;
filldir_t filldir;
int err;
int filldir_called;
int entries_written;
};
/* Inspired by generic filldir in fs/readir.c */
static int
ecryptfs_filldir(void *dirent, const char *name, int namelen, loff_t offset,
u64 ino, unsigned int d_type)
{
struct ecryptfs_crypt_stat *crypt_stat;
struct ecryptfs_getdents_callback *buf =
(struct ecryptfs_getdents_callback *)dirent;
int rc;
int decoded_length;
char *decoded_name;
crypt_stat = ecryptfs_dentry_to_private(buf->dentry)->crypt_stat;
buf->filldir_called++;
decoded_length = ecryptfs_decode_filename(crypt_stat, name, namelen,
&decoded_name);
if (decoded_length < 0) {
rc = decoded_length;
goto out;
}
rc = buf->filldir(buf->dirent, decoded_name, decoded_length, offset,
ino, d_type);
kfree(decoded_name);
if (rc >= 0)
buf->entries_written++;
out:
return rc;
}
/**
* ecryptfs_readdir
* @file: The ecryptfs file struct
* @dirent: Directory entry
* @filldir: The filldir callback function
*/
static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
{
int rc;
struct file *lower_file;
struct inode *inode;
struct ecryptfs_getdents_callback buf;
lower_file = ecryptfs_file_to_lower(file);
lower_file->f_pos = file->f_pos;
inode = file->f_path.dentry->d_inode;
memset(&buf, 0, sizeof(buf));
buf.dirent = dirent;
buf.dentry = file->f_path.dentry;
buf.filldir = filldir;
retry:
buf.filldir_called = 0;
buf.entries_written = 0;
buf.err = 0;
rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
if (buf.err)
rc = buf.err;
if (buf.filldir_called && !buf.entries_written)
goto retry;
file->f_pos = lower_file->f_pos;
if (rc >= 0)
fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode);
return rc;
}
struct kmem_cache *ecryptfs_file_info_cache;
int ecryptfs_open_lower_file(struct file **lower_file,
struct dentry *lower_dentry,
struct vfsmount *lower_mnt, int flags)
{
int rc = 0;
flags |= O_LARGEFILE;
dget(lower_dentry);
mntget(lower_mnt);
*lower_file = dentry_open(lower_dentry, lower_mnt, flags);
if (IS_ERR(*lower_file)) {
printk(KERN_ERR "Error opening lower file for lower_dentry "
"[0x%p], lower_mnt [0x%p], and flags [0x%x]\n",
lower_dentry, lower_mnt, flags);
rc = PTR_ERR(*lower_file);
*lower_file = NULL;
goto out;
}
out:
return rc;
}
int ecryptfs_close_lower_file(struct file *lower_file)
{
fput(lower_file);
return 0;
}
/**
* ecryptfs_open
* @inode: inode speciying file to open
* @file: Structure to return filled in
*
* Opens the file specified by inode.
*
* Returns zero on success; non-zero otherwise
*/
static int ecryptfs_open(struct inode *inode, struct file *file)
{
int rc = 0;
struct ecryptfs_crypt_stat *crypt_stat = NULL;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
struct dentry *ecryptfs_dentry = file->f_path.dentry;
/* Private value of ecryptfs_dentry allocated in
* ecryptfs_lookup() */
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
struct inode *lower_inode = NULL;
struct file *lower_file = NULL;
struct vfsmount *lower_mnt;
struct ecryptfs_file_info *file_info;
int lower_flags;
mount_crypt_stat = &ecryptfs_superblock_to_private(
ecryptfs_dentry->d_sb)->mount_crypt_stat;
if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
&& ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
|| (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
|| (file->f_flags & O_APPEND))) {
printk(KERN_WARNING "Mount has encrypted view enabled; "
"files may only be read\n");
rc = -EPERM;
goto out;
}
/* Released in ecryptfs_release or end of function if failure */
file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
ecryptfs_set_file_private(file, file_info);
if (!file_info) {
ecryptfs_printk(KERN_ERR,
"Error attempting to allocate memory\n");
rc = -ENOMEM;
goto out;
}
lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
mutex_lock(&crypt_stat->cs_mutex);
if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
/* Policy code enabled in future release */
crypt_stat->flags |= ECRYPTFS_POLICY_APPLIED;
crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
}
mutex_unlock(&crypt_stat->cs_mutex);
lower_flags = file->f_flags;
if ((lower_flags & O_ACCMODE) == O_WRONLY)
lower_flags = (lower_flags & O_ACCMODE) | O_RDWR;
if (file->f_flags & O_APPEND)
lower_flags &= ~O_APPEND;
lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
/* Corresponding fput() in ecryptfs_release() */
if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
lower_flags))) {
ecryptfs_printk(KERN_ERR, "Error opening lower file\n");
goto out_puts;
}
ecryptfs_set_file_lower(file, lower_file);
/* Isn't this check the same as the one in lookup? */
lower_inode = lower_dentry->d_inode;
if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
rc = 0;
goto out;
}
mutex_lock(&crypt_stat->cs_mutex);
if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
|| !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
rc = ecryptfs_read_metadata(ecryptfs_dentry, lower_file);
if (rc) {
ecryptfs_printk(KERN_DEBUG,
"Valid headers not found\n");
if (!(mount_crypt_stat->flags
& ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
rc = -EIO;
printk(KERN_WARNING "Attempt to read file that "
"is not in a valid eCryptfs format, "
"and plaintext passthrough mode is not "
"enabled; returning -EIO\n");
mutex_unlock(&crypt_stat->cs_mutex);
goto out_puts;
}
rc = 0;
crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
mutex_unlock(&crypt_stat->cs_mutex);
goto out;
}
}
mutex_unlock(&crypt_stat->cs_mutex);
ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
"size: [0x%.16x]\n", inode, inode->i_ino,
i_size_read(inode));
ecryptfs_set_file_lower(file, lower_file);
goto out;
out_puts:
mntput(lower_mnt);
dput(lower_dentry);
kmem_cache_free(ecryptfs_file_info_cache,
ecryptfs_file_to_private(file));
out:
return rc;
}
static int ecryptfs_flush(struct file *file, fl_owner_t td)
{
int rc = 0;
struct file *lower_file = NULL;
lower_file = ecryptfs_file_to_lower(file);
if (lower_file->f_op && lower_file->f_op->flush)
rc = lower_file->f_op->flush(lower_file, td);
return rc;
}
static int ecryptfs_release(struct inode *inode, struct file *file)
{
struct file *lower_file = ecryptfs_file_to_lower(file);
struct ecryptfs_file_info *file_info = ecryptfs_file_to_private(file);
struct inode *lower_inode = ecryptfs_inode_to_lower(inode);
int rc;
if ((rc = ecryptfs_close_lower_file(lower_file))) {
printk(KERN_ERR "Error closing lower_file\n");
goto out;
}
inode->i_blocks = lower_inode->i_blocks;
kmem_cache_free(ecryptfs_file_info_cache, file_info);
out:
return rc;
}
static int
ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
{
struct file *lower_file = ecryptfs_file_to_lower(file);
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
struct inode *lower_inode = lower_dentry->d_inode;
int rc = -EINVAL;
if (lower_inode->i_fop->fsync) {
mutex_lock(&lower_inode->i_mutex);
rc = lower_inode->i_fop->fsync(lower_file, lower_dentry,
datasync);
mutex_unlock(&lower_inode->i_mutex);
}
return rc;
}
static int ecryptfs_fasync(int fd, struct file *file, int flag)
{
int rc = 0;
struct file *lower_file = NULL;
lower_file = ecryptfs_file_to_lower(file);
if (lower_file->f_op && lower_file->f_op->fasync)
rc = lower_file->f_op->fasync(fd, lower_file, flag);
return rc;
}
static ssize_t ecryptfs_sendfile(struct file *file, loff_t * ppos,
size_t count, read_actor_t actor, void *target)
{
struct file *lower_file = NULL;
int rc = -EINVAL;
lower_file = ecryptfs_file_to_lower(file);
if (lower_file->f_op && lower_file->f_op->sendfile)
rc = lower_file->f_op->sendfile(lower_file, ppos, count,
actor, target);
return rc;
}
static int ecryptfs_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg);
const struct file_operations ecryptfs_dir_fops = {
.readdir = ecryptfs_readdir,
.ioctl = ecryptfs_ioctl,
.mmap = generic_file_mmap,
.open = ecryptfs_open,
.flush = ecryptfs_flush,
.release = ecryptfs_release,
.fsync = ecryptfs_fsync,
.fasync = ecryptfs_fasync,
.sendfile = ecryptfs_sendfile,
};
const struct file_operations ecryptfs_main_fops = {
.llseek = ecryptfs_llseek,
.read = do_sync_read,
.aio_read = ecryptfs_read_update_atime,
.write = do_sync_write,
.aio_write = generic_file_aio_write,
.readdir = ecryptfs_readdir,
.ioctl = ecryptfs_ioctl,
.mmap = generic_file_mmap,
.open = ecryptfs_open,
.flush = ecryptfs_flush,
.release = ecryptfs_release,
.fsync = ecryptfs_fsync,
.fasync = ecryptfs_fasync,
.sendfile = ecryptfs_sendfile,
};
static int
ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
int rc = 0;
struct file *lower_file = NULL;
if (ecryptfs_file_to_private(file))
lower_file = ecryptfs_file_to_lower(file);
if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
lower_file, cmd, arg);
else
rc = -ENOTTY;
return rc;
}
