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![Linus Torvalds](/assets/img/avatar_default.png)
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Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
https://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
1d7b902e28
In order to support idmapped mounts, filesystems need to be changed
and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
patches to convert individual filesystem are not very large or
complicated overall as can be seen from the included fat, ext4, and
xfs ports. Patches for other filesystems are actively worked on and
will be sent out separately. The xfstestsuite can be used to verify
that port has been done correctly.
The mount_setattr() syscall is motivated independent of the idmapped
mounts patches and it's been around since July 2019. One of the most
valuable features of the new mount api is the ability to perform
mounts based on file descriptors only.
Together with the lookup restrictions available in the openat2()
RESOLVE_* flag namespace which we added in v5.6 this is the first time
we are close to hardened and race-free (e.g. symlinks) mounting and
path resolution.
While userspace has started porting to the new mount api to mount
proper filesystems and create new bind-mounts it is currently not
possible to change mount options of an already existing bind mount in
the new mount api since the mount_setattr() syscall is missing.
With the addition of the mount_setattr() syscall we remove this last
restriction and userspace can now fully port to the new mount api,
covering every use-case the old mount api could. We also add the
crucial ability to recursively change mount options for a whole mount
tree, both removing and adding mount options at the same time. This
syscall has been requested multiple times by various people and
projects.
There is a simple tool available at
https://github.com/brauner/mount-idmapped
that allows to create idmapped mounts so people can play with this
patch series. I'll add support for the regular mount binary should you
decide to pull this in the following weeks:
Here's an example to a simple idmapped mount of another user's home
directory:
u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt
u1001@f2-vm:/$ ls -al /home/ubuntu/
total 28
drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
drwxr-xr-x 4 root root 4096 Oct 28 04:00 ..
-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile
-rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ ls -al /mnt/
total 28
drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 .
drwxr-xr-x 29 root root 4096 Oct 28 22:01 ..
-rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile
-rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ touch /mnt/my-file
u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file
u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file
u1001@f2-vm:/$ ls -al /mnt/my-file
-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file
u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file
u1001@f2-vm:/$ getfacl /mnt/my-file
getfacl: Removing leading '/' from absolute path names
# file: mnt/my-file
# owner: u1001
# group: u1001
user::rw-
user:u1001:rwx
group::rw-
mask::rwx
other::r--
u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
getfacl: Removing leading '/' from absolute path names
# file: home/ubuntu/my-file
# owner: ubuntu
# group: ubuntu
user::rw-
user:ubuntu:rwx
group::rw-
mask::rwx
other::r--"
* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
xfs: support idmapped mounts
ext4: support idmapped mounts
fat: handle idmapped mounts
tests: add mount_setattr() selftests
fs: introduce MOUNT_ATTR_IDMAP
fs: add mount_setattr()
fs: add attr_flags_to_mnt_flags helper
fs: split out functions to hold writers
namespace: only take read lock in do_reconfigure_mnt()
mount: make {lock,unlock}_mount_hash() static
namespace: take lock_mount_hash() directly when changing flags
nfs: do not export idmapped mounts
overlayfs: do not mount on top of idmapped mounts
ecryptfs: do not mount on top of idmapped mounts
ima: handle idmapped mounts
apparmor: handle idmapped mounts
fs: make helpers idmap mount aware
exec: handle idmapped mounts
would_dump: handle idmapped mounts
...
1181 lines
33 KiB
C
1181 lines
33 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/**
|
|
* eCryptfs: Linux filesystem encryption layer
|
|
*
|
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* Copyright (C) 1997-2004 Erez Zadok
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* Copyright (C) 2001-2004 Stony Brook University
|
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* Copyright (C) 2004-2007 International Business Machines Corp.
|
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* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
|
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* Michael C. Thompsion <mcthomps@us.ibm.com>
|
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*/
|
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|
|
#include <linux/file.h>
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#include <linux/vmalloc.h>
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#include <linux/pagemap.h>
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#include <linux/dcache.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/fs_stack.h>
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#include <linux/slab.h>
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#include <linux/xattr.h>
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#include <asm/unaligned.h>
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#include "ecryptfs_kernel.h"
|
|
|
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static struct dentry *lock_parent(struct dentry *dentry)
|
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{
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struct dentry *dir;
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|
|
|
dir = dget_parent(dentry);
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|
inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
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return dir;
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}
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|
|
|
static void unlock_dir(struct dentry *dir)
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|
{
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|
inode_unlock(d_inode(dir));
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|
dput(dir);
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|
}
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|
|
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static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
|
|
{
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return ecryptfs_inode_to_lower(inode) == lower_inode;
|
|
}
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|
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static int ecryptfs_inode_set(struct inode *inode, void *opaque)
|
|
{
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struct inode *lower_inode = opaque;
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|
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ecryptfs_set_inode_lower(inode, lower_inode);
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fsstack_copy_attr_all(inode, lower_inode);
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/* i_size will be overwritten for encrypted regular files */
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fsstack_copy_inode_size(inode, lower_inode);
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inode->i_ino = lower_inode->i_ino;
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inode->i_mapping->a_ops = &ecryptfs_aops;
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|
|
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if (S_ISLNK(inode->i_mode))
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inode->i_op = &ecryptfs_symlink_iops;
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else if (S_ISDIR(inode->i_mode))
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inode->i_op = &ecryptfs_dir_iops;
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else
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inode->i_op = &ecryptfs_main_iops;
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|
|
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if (S_ISDIR(inode->i_mode))
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inode->i_fop = &ecryptfs_dir_fops;
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else if (special_file(inode->i_mode))
|
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init_special_inode(inode, inode->i_mode, inode->i_rdev);
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else
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inode->i_fop = &ecryptfs_main_fops;
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|
|
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return 0;
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}
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static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
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struct super_block *sb)
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{
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struct inode *inode;
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|
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if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
|
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return ERR_PTR(-EXDEV);
|
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if (!igrab(lower_inode))
|
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return ERR_PTR(-ESTALE);
|
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inode = iget5_locked(sb, (unsigned long)lower_inode,
|
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ecryptfs_inode_test, ecryptfs_inode_set,
|
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lower_inode);
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if (!inode) {
|
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iput(lower_inode);
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return ERR_PTR(-EACCES);
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}
|
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if (!(inode->i_state & I_NEW))
|
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iput(lower_inode);
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|
|
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return inode;
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}
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|
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struct inode *ecryptfs_get_inode(struct inode *lower_inode,
|
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struct super_block *sb)
|
|
{
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struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
|
|
|
|
if (!IS_ERR(inode) && (inode->i_state & I_NEW))
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unlock_new_inode(inode);
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|
|
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return inode;
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}
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|
|
|
/**
|
|
* ecryptfs_interpose
|
|
* @lower_dentry: Existing dentry in the lower filesystem
|
|
* @dentry: ecryptfs' dentry
|
|
* @sb: ecryptfs's super_block
|
|
*
|
|
* Interposes upper and lower dentries.
|
|
*
|
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* Returns zero on success; non-zero otherwise
|
|
*/
|
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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 dentry *lower_dir_dentry;
|
|
struct inode *lower_dir_inode;
|
|
int rc;
|
|
|
|
lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
|
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lower_dir_inode = d_inode(lower_dir_dentry);
|
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inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
|
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dget(lower_dentry); // don't even try to make the lower negative
|
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if (lower_dentry->d_parent != lower_dir_dentry)
|
|
rc = -EINVAL;
|
|
else if (d_unhashed(lower_dentry))
|
|
rc = -EINVAL;
|
|
else
|
|
rc = vfs_unlink(&init_user_ns, lower_dir_inode, lower_dentry,
|
|
NULL);
|
|
if (rc) {
|
|
printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
|
|
goto out_unlock;
|
|
}
|
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fsstack_copy_attr_times(dir, lower_dir_inode);
|
|
set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
|
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inode->i_ctime = dir->i_ctime;
|
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out_unlock:
|
|
dput(lower_dentry);
|
|
inode_unlock(lower_dir_inode);
|
|
if (!rc)
|
|
d_drop(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(&init_user_ns, 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(&init_user_ns, 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
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|
*/
|
|
int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
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|
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)) {
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|
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 user_namespace *mnt_userns,
|
|
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;
|
|
}
|
|
d_instantiate_new(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 struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
|
|
struct dentry *lower_dentry)
|
|
{
|
|
struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
|
|
struct inode *inode, *lower_inode;
|
|
struct ecryptfs_dentry_info *dentry_info;
|
|
int rc = 0;
|
|
|
|
dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
|
|
if (!dentry_info) {
|
|
dput(lower_dentry);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
fsstack_copy_attr_atime(d_inode(dentry->d_parent),
|
|
d_inode(path->dentry));
|
|
BUG_ON(!d_count(lower_dentry));
|
|
|
|
ecryptfs_set_dentry_private(dentry, dentry_info);
|
|
dentry_info->lower_path.mnt = mntget(path->mnt);
|
|
dentry_info->lower_path.dentry = lower_dentry;
|
|
|
|
/*
|
|
* negative dentry can go positive under us here - its parent is not
|
|
* locked. That's OK and that could happen just as we return from
|
|
* ecryptfs_lookup() anyway. Just need to be careful and fetch
|
|
* ->d_inode only once - it's not stable here.
|
|
*/
|
|
lower_inode = READ_ONCE(lower_dentry->d_inode);
|
|
|
|
if (!lower_inode) {
|
|
/* We want to add because we couldn't find in lower */
|
|
d_add(dentry, NULL);
|
|
return NULL;
|
|
}
|
|
inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
|
|
if (IS_ERR(inode)) {
|
|
printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
|
|
__func__, PTR_ERR(inode));
|
|
return ERR_CAST(inode);
|
|
}
|
|
if (S_ISREG(inode->i_mode)) {
|
|
rc = ecryptfs_i_size_read(dentry, inode);
|
|
if (rc) {
|
|
make_bad_inode(inode);
|
|
return ERR_PTR(rc);
|
|
}
|
|
}
|
|
|
|
if (inode->i_state & I_NEW)
|
|
unlock_new_inode(inode);
|
|
return d_splice_alias(inode, dentry);
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
|
|
struct dentry *lower_dir_dentry, *lower_dentry;
|
|
const char *name = ecryptfs_dentry->d_name.name;
|
|
size_t len = ecryptfs_dentry->d_name.len;
|
|
struct dentry *res;
|
|
int rc = 0;
|
|
|
|
lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
|
|
|
|
mount_crypt_stat = &ecryptfs_superblock_to_private(
|
|
ecryptfs_dentry->d_sb)->mount_crypt_stat;
|
|
if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
|
|
rc = ecryptfs_encrypt_and_encode_filename(
|
|
&encrypted_and_encoded_name, &len,
|
|
mount_crypt_stat, name, len);
|
|
if (rc) {
|
|
printk(KERN_ERR "%s: Error attempting to encrypt and encode "
|
|
"filename; rc = [%d]\n", __func__, rc);
|
|
return ERR_PTR(rc);
|
|
}
|
|
name = encrypted_and_encoded_name;
|
|
}
|
|
|
|
lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
|
|
if (IS_ERR(lower_dentry)) {
|
|
ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
|
|
"[%ld] on lower_dentry = [%s]\n", __func__,
|
|
PTR_ERR(lower_dentry),
|
|
name);
|
|
res = ERR_CAST(lower_dentry);
|
|
} else {
|
|
res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
|
|
}
|
|
kfree(encrypted_and_encoded_name);
|
|
return res;
|
|
}
|
|
|
|
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, &init_user_ns,
|
|
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 user_namespace *mnt_userns,
|
|
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(&init_user_ns, 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 user_namespace *mnt_userns, 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(&init_user_ns, 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;
|
|
struct inode *lower_dir_inode;
|
|
int rc;
|
|
|
|
lower_dentry = ecryptfs_dentry_to_lower(dentry);
|
|
lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
|
|
lower_dir_inode = d_inode(lower_dir_dentry);
|
|
|
|
inode_lock_nested(lower_dir_inode, I_MUTEX_PARENT);
|
|
dget(lower_dentry); // don't even try to make the lower negative
|
|
if (lower_dentry->d_parent != lower_dir_dentry)
|
|
rc = -EINVAL;
|
|
else if (d_unhashed(lower_dentry))
|
|
rc = -EINVAL;
|
|
else
|
|
rc = vfs_rmdir(&init_user_ns, lower_dir_inode, lower_dentry);
|
|
if (!rc) {
|
|
clear_nlink(d_inode(dentry));
|
|
fsstack_copy_attr_times(dir, lower_dir_inode);
|
|
set_nlink(dir, lower_dir_inode->i_nlink);
|
|
}
|
|
dput(lower_dentry);
|
|
inode_unlock(lower_dir_inode);
|
|
if (!rc)
|
|
d_drop(dentry);
|
|
return rc;
|
|
}
|
|
|
|
static int
|
|
ecryptfs_mknod(struct user_namespace *mnt_userns, 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(&init_user_ns, 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 user_namespace *mnt_userns, struct inode *old_dir,
|
|
struct dentry *old_dentry, struct inode *new_dir,
|
|
struct dentry *new_dentry, unsigned int flags)
|
|
{
|
|
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;
|
|
struct inode *target_inode;
|
|
struct renamedata rd = {};
|
|
|
|
if (flags)
|
|
return -EINVAL;
|
|
|
|
lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
|
|
lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
|
|
|
|
lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
|
|
lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
|
|
|
|
target_inode = d_inode(new_dentry);
|
|
|
|
trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
|
|
dget(lower_new_dentry);
|
|
rc = -EINVAL;
|
|
if (lower_old_dentry->d_parent != lower_old_dir_dentry)
|
|
goto out_lock;
|
|
if (lower_new_dentry->d_parent != lower_new_dir_dentry)
|
|
goto out_lock;
|
|
if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
|
|
goto out_lock;
|
|
/* source should not be ancestor of target */
|
|
if (trap == lower_old_dentry)
|
|
goto out_lock;
|
|
/* target should not be ancestor of source */
|
|
if (trap == lower_new_dentry) {
|
|
rc = -ENOTEMPTY;
|
|
goto out_lock;
|
|
}
|
|
|
|
rd.old_mnt_userns = &init_user_ns;
|
|
rd.old_dir = d_inode(lower_old_dir_dentry);
|
|
rd.old_dentry = lower_old_dentry;
|
|
rd.new_mnt_userns = &init_user_ns;
|
|
rd.new_dir = d_inode(lower_new_dir_dentry);
|
|
rd.new_dentry = lower_new_dentry;
|
|
rc = vfs_rename(&rd);
|
|
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:
|
|
dput(lower_new_dentry);
|
|
unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
|
|
return rc;
|
|
}
|
|
|
|
static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
|
|
{
|
|
DEFINE_DELAYED_CALL(done);
|
|
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
|
|
const char *link;
|
|
char *buf;
|
|
int rc;
|
|
|
|
link = vfs_get_link(lower_dentry, &done);
|
|
if (IS_ERR(link))
|
|
return ERR_CAST(link);
|
|
|
|
rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
|
|
link, strlen(link));
|
|
do_delayed_call(&done);
|
|
if (rc)
|
|
return ERR_PTR(rc);
|
|
|
|
return 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(&init_user_ns, lower_dentry,
|
|
&lower_ia, NULL);
|
|
inode_unlock(d_inode(lower_dentry));
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
static int
|
|
ecryptfs_permission(struct user_namespace *mnt_userns, struct inode *inode,
|
|
int mask)
|
|
{
|
|
return inode_permission(&init_user_ns,
|
|
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 user_namespace *mnt_userns,
|
|
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 = setattr_prepare(&init_user_ns, dentry, 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(&init_user_ns, 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 user_namespace *mnt_userns,
|
|
const struct path *path, struct kstat *stat,
|
|
u32 request_mask, unsigned int flags)
|
|
{
|
|
struct dentry *dentry = path->dentry;
|
|
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(&init_user_ns, 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 user_namespace *mnt_userns,
|
|
const struct path *path, struct kstat *stat,
|
|
u32 request_mask, unsigned int flags)
|
|
{
|
|
struct dentry *dentry = path->dentry;
|
|
struct kstat lower_stat;
|
|
int rc;
|
|
|
|
rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat,
|
|
request_mask, flags);
|
|
if (!rc) {
|
|
fsstack_copy_attr_all(d_inode(dentry),
|
|
ecryptfs_inode_to_lower(d_inode(dentry)));
|
|
generic_fillattr(&init_user_ns, d_inode(dentry), stat);
|
|
stat->blocks = lower_stat.blocks;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
int
|
|
ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
|
|
const char *name, const void *value,
|
|
size_t size, int flags)
|
|
{
|
|
int rc;
|
|
struct dentry *lower_dentry;
|
|
struct inode *lower_inode;
|
|
|
|
lower_dentry = ecryptfs_dentry_to_lower(dentry);
|
|
lower_inode = d_inode(lower_dentry);
|
|
if (!(lower_inode->i_opflags & IOP_XATTR)) {
|
|
rc = -EOPNOTSUPP;
|
|
goto out;
|
|
}
|
|
inode_lock(lower_inode);
|
|
rc = __vfs_setxattr_locked(&init_user_ns, lower_dentry, name, value, size, flags, NULL);
|
|
inode_unlock(lower_inode);
|
|
if (!rc && inode)
|
|
fsstack_copy_attr_all(inode, lower_inode);
|
|
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;
|
|
|
|
if (!(lower_inode->i_opflags & IOP_XATTR)) {
|
|
rc = -EOPNOTSUPP;
|
|
goto out;
|
|
}
|
|
inode_lock(lower_inode);
|
|
rc = __vfs_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, struct inode *inode,
|
|
const char *name)
|
|
{
|
|
int rc;
|
|
struct dentry *lower_dentry;
|
|
struct inode *lower_inode;
|
|
|
|
lower_dentry = ecryptfs_dentry_to_lower(dentry);
|
|
lower_inode = ecryptfs_inode_to_lower(inode);
|
|
if (!(lower_inode->i_opflags & IOP_XATTR)) {
|
|
rc = -EOPNOTSUPP;
|
|
goto out;
|
|
}
|
|
inode_lock(lower_inode);
|
|
rc = __vfs_removexattr(&init_user_ns, lower_dentry, name);
|
|
inode_unlock(lower_inode);
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
const struct inode_operations ecryptfs_symlink_iops = {
|
|
.get_link = ecryptfs_get_link,
|
|
.permission = ecryptfs_permission,
|
|
.setattr = ecryptfs_setattr,
|
|
.getattr = ecryptfs_getattr_link,
|
|
.listxattr = ecryptfs_listxattr,
|
|
};
|
|
|
|
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,
|
|
.listxattr = ecryptfs_listxattr,
|
|
};
|
|
|
|
const struct inode_operations ecryptfs_main_iops = {
|
|
.permission = ecryptfs_permission,
|
|
.setattr = ecryptfs_setattr,
|
|
.getattr = ecryptfs_getattr,
|
|
.listxattr = ecryptfs_listxattr,
|
|
};
|
|
|
|
static int ecryptfs_xattr_get(const struct xattr_handler *handler,
|
|
struct dentry *dentry, struct inode *inode,
|
|
const char *name, void *buffer, size_t size)
|
|
{
|
|
return ecryptfs_getxattr(dentry, inode, name, buffer, size);
|
|
}
|
|
|
|
static int ecryptfs_xattr_set(const struct xattr_handler *handler,
|
|
struct user_namespace *mnt_userns,
|
|
struct dentry *dentry, struct inode *inode,
|
|
const char *name, const void *value, size_t size,
|
|
int flags)
|
|
{
|
|
if (value)
|
|
return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
|
|
else {
|
|
BUG_ON(flags != XATTR_REPLACE);
|
|
return ecryptfs_removexattr(dentry, inode, name);
|
|
}
|
|
}
|
|
|
|
static const struct xattr_handler ecryptfs_xattr_handler = {
|
|
.prefix = "", /* match anything */
|
|
.get = ecryptfs_xattr_get,
|
|
.set = ecryptfs_xattr_set,
|
|
};
|
|
|
|
const struct xattr_handler *ecryptfs_xattr_handlers[] = {
|
|
&ecryptfs_xattr_handler,
|
|
NULL
|
|
};
|