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7f427d3a60
linux/fs/ecryptfs/inode.c
Linus Torvalds 7f427d3a60 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 
Pull parallel filesystem directory handling update from Al Viro.

This is the main parallel directory work by Al that makes the vfs layer
able to do lookup and readdir in parallel within a single directory.
That's a big change, since this used to be all protected by the
directory inode mutex.

The inode mutex is replaced by an rwsem, and serialization of lookups of
a single name is done by a "in-progress" dentry marker.

The series begins with xattr cleanups, and then ends with switching
filesystems over to actually doing the readdir in parallel (switching to
the "iterate_shared()" that only takes the read lock).

A more detailed explanation of the process from Al Viro:
 "The xattr work starts with some acl fixes, then switches ->getxattr to
  passing inode and dentry separately.  This is the point where the
  things start to get tricky - that got merged into the very beginning
  of the -rc3-based #work.lookups, to allow untangling the
  security_d_instantiate() mess.  The xattr work itself proceeds to
  switch a lot of filesystems to generic_...xattr(); no complications
  there.

  After that initial xattr work, the series then does the following:

   - untangle security_d_instantiate()

   - convert a bunch of open-coded lookup_one_len_unlocked() to calls of
     that thing; one such place (in overlayfs) actually yields a trivial
     conflict with overlayfs fixes later in the cycle - overlayfs ended
     up switching to a variant of lookup_one_len_unlocked() sans the
     permission checks.  I would've dropped that commit (it gets
     overridden on merge from #ovl-fixes in #for-next; proper resolution
     is to use the variant in mainline fs/overlayfs/super.c), but I
     didn't want to rebase the damn thing - it was fairly late in the
     cycle...

   - some filesystems had managed to depend on lookup/lookup exclusion
     for *fs-internal* data structures in a way that would break if we
     relaxed the VFS exclusion.  Fixing hadn't been hard, fortunately.

   - core of that series - parallel lookup machinery, replacing
     ->i_mutex with rwsem, making lookup_slow() take it only shared.  At
     that point lookups happen in parallel; lookups on the same name
     wait for the in-progress one to be done with that dentry.

     Surprisingly little code, at that - almost all of it is in
     fs/dcache.c, with fs/namei.c changes limited to lookup_slow() -
     making it use the new primitive and actually switching to locking
     shared.

   - parallel readdir stuff - first of all, we provide the exclusion on
     per-struct file basis, same as we do for read() vs lseek() for
     regular files.  That takes care of most of the needed exclusion in
     readdir/readdir; however, these guys are trickier than lookups, so
     I went for switching them one-by-one.  To do that, a new method
     '->iterate_shared()' is added and filesystems are switched to it
     as they are either confirmed to be OK with shared lock on directory
     or fixed to be OK with that.  I hope to kill the original method
     come next cycle (almost all in-tree filesystems are switched
     already), but it's still not quite finished.

   - several filesystems get switched to parallel readdir.  The
     interesting part here is dealing with dcache preseeding by readdir;
     that needs minor adjustment to be safe with directory locked only
     shared.

     Most of the filesystems doing that got switched to in those
     commits.  Important exception: NFS.  Turns out that NFS folks, with
     their, er, insistence on VFS getting the fuck out of the way of the
     Smart Filesystem Code That Knows How And What To Lock(tm) have
     grown the locking of their own.  They had their own homegrown
     rwsem, with lookup/readdir/atomic_open being *writers* (sillyunlink
     is the reader there).  Of course, with VFS getting the fuck out of
     the way, as requested, the actual smarts of the smart filesystem
     code etc. had become exposed...

   - do_last/lookup_open/atomic_open cleanups.  As the result, open()
     without O_CREAT locks the directory only shared.  Including the
     ->atomic_open() case.  Backmerge from #for-linus in the middle of
     that - atomic_open() fix got brought in.

   - then comes NFS switch to saner (VFS-based ;-) locking, killing the
     homegrown "lookup and readdir are writers" kinda-sorta rwsem.  All
     exclusion for sillyunlink/lookup is done by the parallel lookups
     mechanism.  Exclusion between sillyunlink and rmdir is a real rwsem
     now - rmdir being the writer.

     Result: NFS lookups/readdirs/O_CREAT-less opens happen in parallel
     now.

   - the rest of the series consists of switching a lot of filesystems
     to parallel readdir; in a lot of cases ->llseek() gets simplified
     as well.  One backmerge in there (again, #for-linus - rockridge
     fix)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (74 commits)
  ext4: switch to ->iterate_shared()
  hfs: switch to ->iterate_shared()
  hfsplus: switch to ->iterate_shared()
  hostfs: switch to ->iterate_shared()
  hpfs: switch to ->iterate_shared()
  hpfs: handle allocation failures in hpfs_add_pos()
  gfs2: switch to ->iterate_shared()
  f2fs: switch to ->iterate_shared()
  afs: switch to ->iterate_shared()
  befs: switch to ->iterate_shared()
  befs: constify stuff a bit
  isofs: switch to ->iterate_shared()
  get_acorn_filename(): deobfuscate a bit
  btrfs: switch to ->iterate_shared()
  logfs: no need to lock directory in lseek
  switch ecryptfs to ->iterate_shared
  9p: switch to ->iterate_shared()
  fat: switch to ->iterate_shared()
  romfs, squashfs: switch to ->iterate_shared()
  more trivial ->iterate_shared conversions
  ...
2016-05-17 11:01:31 -07:00

1139 lines
32 KiB
C
Raw Blame History

/**
* 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/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);
inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
return dir;
}
static void unlock_dir(struct dentry *dir)
{
inode_unlock(d_inode(dir));
dput(dir);
}
static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
{
return ecryptfs_inode_to_lower(inode) == lower_inode;
}
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;
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(d_inode(lower_dentry), sb);
if (IS_ERR(inode))
return PTR_ERR(inode);
d_instantiate(dentry, inode);
return 0;
}
static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
struct inode *inode)
{
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
struct dentry *lower_dir_dentry;
int rc;
dget(lower_dentry);
lower_dir_dentry = lock_parent(lower_dentry);
rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
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(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
inode->i_ctime = dir->i_ctime;
d_drop(dentry);
out_unlock:
unlock_dir(lower_dir_dentry);
dput(lower_dentry);
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
*
* 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);
rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
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(d_inode(lower_dentry),
directory_inode->i_sb);
if (IS_ERR(inode)) {
vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
goto out_lock;
}
fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
out_lock:
unlock_dir(lower_dir_dentry);
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
*/
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 "
"[%pd]; rc = [%d]\n", __func__,
ecryptfs_dentry, 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.
*
* 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, bool excl)
{
struct inode *ecryptfs_inode;
int rc;
ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
mode);
if (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) {
ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
ecryptfs_inode);
iget_failed(ecryptfs_inode);
goto out;
}
unlock_new_inode(ecryptfs_inode);
d_instantiate(ecryptfs_dentry, 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 "
"[%pd]; rc = [%d]\n", __func__,
dentry, 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 = d_inode(lower_dentry);
struct ecryptfs_dentry_info *dentry_info;
struct vfsmount *lower_mnt;
int rc = 0;
dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
if (!dentry_info) {
printk(KERN_ERR "%s: Out of memory whilst attempting "
"to allocate ecryptfs_dentry_info struct\n",
__func__);
dput(lower_dentry);
return -ENOMEM;
}
lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
fsstack_copy_attr_atime(dir_inode, d_inode(lower_dentry->d_parent));
BUG_ON(!d_count(lower_dentry));
ecryptfs_set_dentry_private(dentry, dentry_info);
dentry_info->lower_path.mnt = lower_mnt;
dentry_info->lower_path.dentry = lower_dentry;
if (d_really_is_negative(lower_dentry)) {
/* 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
* @flags: lookup flags
*
* 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,
unsigned int flags)
{
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;
lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
lower_dentry = lookup_one_len_unlocked(ecryptfs_dentry->d_name.name,
lower_dir_dentry,
ecryptfs_dentry->d_name.len);
if (IS_ERR(lower_dentry)) {
rc = PTR_ERR(lower_dentry);
ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
"[%d] on lower_dentry = [%pd]\n", __func__, rc,
ecryptfs_dentry);
goto out;
}
if (d_really_is_positive(lower_dentry))
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,
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;
}
lower_dentry = lookup_one_len_unlocked(encrypted_and_encoded_name,
lower_dir_dentry,
encrypted_and_encoded_name_size);
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;
}
interpose:
rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
ecryptfs_dir_inode);
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(d_inode(old_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_dir_dentry = lock_parent(lower_new_dentry);
rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
lower_new_dentry, NULL);
if (rc || d_really_is_negative(lower_new_dentry))
goto out_lock;
rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
if (rc)
goto out_lock;
fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
set_nlink(d_inode(old_dentry),
ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
i_size_write(d_inode(new_dentry), 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)
{
return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
}
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,
mount_crypt_stat, symname,
strlen(symname));
if (rc)
goto out_lock;
rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
encoded_symname);
kfree(encoded_symname);
if (rc || d_really_is_negative(lower_dentry))
goto out_lock;
rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
if (rc)
goto out_lock;
fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
out_lock:
unlock_dir(lower_dir_dentry);
dput(lower_dentry);
if (d_really_is_negative(dentry))
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(d_inode(lower_dir_dentry), lower_dentry, mode);
if (rc || d_really_is_negative(lower_dentry))
goto out;
rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
if (rc)
goto out;
fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
out:
unlock_dir(lower_dir_dentry);
if (d_really_is_negative(dentry))
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(d_inode(lower_dir_dentry), lower_dentry);
dput(lower_dentry);
if (!rc && d_really_is_positive(dentry))
clear_nlink(d_inode(dentry));
fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
set_nlink(dir, d_inode(lower_dir_dentry)->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(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
if (rc || d_really_is_negative(lower_dentry))
goto out;
rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
if (rc)
goto out;
fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
out:
unlock_dir(lower_dir_dentry);
if (d_really_is_negative(dentry))
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;
struct inode *target_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_old_dir_dentry = dget_parent(lower_old_dentry);
lower_new_dir_dentry = dget_parent(lower_new_dentry);
target_inode = d_inode(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(d_inode(lower_old_dir_dentry), lower_old_dentry,
d_inode(lower_new_dir_dentry), lower_new_dentry,
NULL, 0);
if (rc)
goto out_lock;
if (target_inode)
fsstack_copy_attr_all(target_inode,
ecryptfs_inode_to_lower(target_inode));
fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
if (new_dir != old_dir)
fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
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 char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
{
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
char *lower_buf;
char *buf;
mm_segment_t old_fs;
int rc;
lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
if (!lower_buf)
return ERR_PTR(-ENOMEM);
old_fs = get_fs();
set_fs(get_ds());
rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
(char __user *)lower_buf,
PATH_MAX);
set_fs(old_fs);
if (rc < 0)
goto out;
rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
lower_buf, rc);
out:
kfree(lower_buf);
return rc ? ERR_PTR(rc) : buf;
}
static const char *ecryptfs_get_link(struct dentry *dentry,
struct inode *inode,
struct delayed_call *done)
{
size_t len;
char *buf;
if (!dentry)
return ERR_PTR(-ECHILD);
buf = ecryptfs_readlink_lower(dentry, &len);
if (IS_ERR(buf))
return buf;
fsstack_copy_attr_atime(d_inode(dentry),
d_inode(ecryptfs_dentry_to_lower(dentry)));
buf[len] = '\0';
set_delayed_call(done, kfree_link, buf);
return 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 = d_inode(dentry);
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(d_inode(dentry))->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_MASK) to
* PAGE_SIZE with zeros. */
size_t num_zeros = (PAGE_SIZE
- (ia->ia_size & ~PAGE_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(d_inode(dentry), 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);
inode_lock(d_inode(lower_dentry));
rc = notify_change(lower_dentry, &lower_ia, NULL);
inode_unlock(d_inode(lower_dentry));
}
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(d_inode(dentry))->crypt_stat;
if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
rc = ecryptfs_init_crypt_stat(crypt_stat);
if (rc)
return rc;
}
inode = d_inode(dentry);
lower_inode = ecryptfs_inode_to_lower(inode);
lower_dentry = ecryptfs_dentry_to_lower(dentry);
mutex_lock(&crypt_stat->cs_mutex);
if (d_is_dir(dentry))
crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
else if (d_is_reg(dentry)
&& (!(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;
}
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;
inode_lock(d_inode(lower_dentry));
rc = notify_change(lower_dentry, &lower_ia, NULL);
inode_unlock(d_inode(lower_dentry));
out:
fsstack_copy_attr_all(inode, lower_inode);
return rc;
}
static 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(d_inode(dentry), stat);
if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
char *target;
size_t targetsiz;
target = ecryptfs_readlink_lower(dentry, &targetsiz);
if (!IS_ERR(target)) {
kfree(target);
stat->size = targetsiz;
} else {
rc = PTR_ERR(target);
}
}
return rc;
}
static 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_path(dentry), &lower_stat);
if (!rc) {
fsstack_copy_attr_all(d_inode(dentry),
ecryptfs_inode_to_lower(d_inode(dentry)));
generic_fillattr(d_inode(dentry), 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 (!d_inode(lower_dentry)->i_op->setxattr) {
rc = -EOPNOTSUPP;
goto out;
}
rc = vfs_setxattr(lower_dentry, name, value, size, flags);
if (!rc && d_really_is_positive(dentry))
fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
out:
return rc;
}
ssize_t
ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
const char *name, void *value, size_t size)
{
int rc = 0;
if (!lower_inode->i_op->getxattr) {
rc = -EOPNOTSUPP;
goto out;
}
inode_lock(lower_inode);
rc = lower_inode->i_op->getxattr(lower_dentry, lower_inode,
name, value, size);
inode_unlock(lower_inode);
out:
return rc;
}
static ssize_t
ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
const char *name, void *value, size_t size)
{
return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
ecryptfs_inode_to_lower(inode),
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 (!d_inode(lower_dentry)->i_op->listxattr) {
rc = -EOPNOTSUPP;
goto out;
}
inode_lock(d_inode(lower_dentry));
rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
inode_unlock(d_inode(lower_dentry));
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 (!d_inode(lower_dentry)->i_op->removexattr) {
rc = -EOPNOTSUPP;
goto out;
}
inode_lock(d_inode(lower_dentry));
rc = d_inode(lower_dentry)->i_op->removexattr(lower_dentry, name);
inode_unlock(d_inode(lower_dentry));
out:
return rc;
}
const struct inode_operations ecryptfs_symlink_iops = {
.readlink = generic_readlink,
.get_link = ecryptfs_get_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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