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This cycle we added support for mounting overlayfs on top of idmapped mounts.
Recently I've started looking into potential corner cases when trying to add
additional tests and I noticed that reporting for POSIX ACLs is currently wrong
when using idmapped layers with overlayfs mounted on top of it.
I'm going to give a rather detailed explanation to both the origin of the
problem and the solution.
Let's assume the user creates the following directory layout and they have a
rootfs /var/lib/lxc/c1/rootfs. The files in this rootfs are owned as you would
expect files on your host system to be owned. For example, ~/.bashrc for your
regular user would be owned by 1000:1000 and /root/.bashrc would be owned by
0:0. IOW, this is just regular boring filesystem tree on an ext4 or xfs
filesystem.
The user chooses to set POSIX ACLs using the setfacl binary granting the user
with uid 4 read, write, and execute permissions for their .bashrc file:
setfacl -m u:4:rwx /var/lib/lxc/c2/rootfs/home/ubuntu/.bashrc
Now they to expose the whole rootfs to a container using an idmapped mount. So
they first create:
mkdir -pv /vol/contpool/{ctrover,merge,lowermap,overmap}
mkdir -pv /vol/contpool/ctrover/{over,work}
chown 10000000:10000000 /vol/contpool/ctrover/{over,work}
The user now creates an idmapped mount for the rootfs:
mount-idmapped/mount-idmapped --map-mount=b:0:10000000:65536 \
/var/lib/lxc/c2/rootfs \
/vol/contpool/lowermap
This for example makes it so that /var/lib/lxc/c2/rootfs/home/ubuntu/.bashrc
which is owned by uid and gid 1000 as being owned by uid and gid 10001000 at
/vol/contpool/lowermap/home/ubuntu/.bashrc.
Assume the user wants to expose these idmapped mounts through an overlayfs
mount to a container.
mount -t overlay overlay \
-o lowerdir=/vol/contpool/lowermap, \
upperdir=/vol/contpool/overmap/over, \
workdir=/vol/contpool/overmap/work \
/vol/contpool/merge
The user can do this in two ways:
(1) Mount overlayfs in the initial user namespace and expose it to the
container.
(2) Mount overlayfs on top of the idmapped mounts inside of the container's
user namespace.
Let's assume the user chooses the (1) option and mounts overlayfs on the host
and then changes into a container which uses the idmapping 0:10000000:65536
which is the same used for the two idmapped mounts.
Now the user tries to retrieve the POSIX ACLs using the getfacl command
getfacl -n /vol/contpool/lowermap/home/ubuntu/.bashrc
and to their surprise they see:
# file: vol/contpool/merge/home/ubuntu/.bashrc
# owner: 1000
# group: 1000
user::rw-
user:4294967295:rwx
group::r--
mask::rwx
other::r--
indicating the the uid wasn't correctly translated according to the idmapped
mount. The problem is how we currently translate POSIX ACLs. Let's inspect the
callchain in this example:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:0:4k /* initial idmapping */
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
|> vfs_getxattr()
| -> __vfs_getxattr()
| -> handler->get == ovl_posix_acl_xattr_get()
| -> ovl_xattr_get()
| -> vfs_getxattr()
| -> __vfs_getxattr()
| -> handler->get() /* lower filesystem callback */
|> posix_acl_fix_xattr_to_user()
{
4 = make_kuid(&init_user_ns, 4);
4 = mapped_kuid_fs(&init_user_ns /* no idmapped mount */, 4);
/* FAILURE */
-1 = from_kuid(0:10000000:65536 /* caller's idmapping */, 4);
}
If the user chooses to use option (2) and mounts overlayfs on top of idmapped
mounts inside the container things don't look that much better:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:10000000:65536
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
|> vfs_getxattr()
| -> __vfs_getxattr()
| -> handler->get == ovl_posix_acl_xattr_get()
| -> ovl_xattr_get()
| -> vfs_getxattr()
| -> __vfs_getxattr()
| -> handler->get() /* lower filesystem callback */
|> posix_acl_fix_xattr_to_user()
{
4 = make_kuid(&init_user_ns, 4);
4 = mapped_kuid_fs(&init_user_ns, 4);
/* FAILURE */
-1 = from_kuid(0:10000000:65536 /* caller's idmapping */, 4);
}
As is easily seen the problem arises because the idmapping of the lower mount
isn't taken into account as all of this happens in do_gexattr(). But
do_getxattr() is always called on an overlayfs mount and inode and thus cannot
possible take the idmapping of the lower layers into account.
This problem is similar for fscaps but there the translation happens as part of
vfs_getxattr() already. Let's walk through an fscaps overlayfs callchain:
setcap 'cap_net_raw+ep' /var/lib/lxc/c2/rootfs/home/ubuntu/.bashrc
The expected outcome here is that we'll receive the cap_net_raw capability as
we are able to map the uid associated with the fscap to 0 within our container.
IOW, we want to see 0 as the result of the idmapping translations.
If the user chooses option (1) we get the following callchain for fscaps:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:0:4k /* initial idmapping */
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
-> vfs_getxattr()
-> xattr_getsecurity()
-> security_inode_getsecurity() ________________________________
-> cap_inode_getsecurity() | |
{ V |
10000000 = make_kuid(0:0:4k /* overlayfs idmapping */, 10000000); |
10000000 = mapped_kuid_fs(0:0:4k /* no idmapped mount */, 10000000); |
/* Expected result is 0 and thus that we own the fscap. */ |
0 = from_kuid(0:10000000:65536 /* caller's idmapping */, 10000000); |
} |
-> vfs_getxattr_alloc() |
-> handler->get == ovl_other_xattr_get() |
-> vfs_getxattr() |
-> xattr_getsecurity() |
-> security_inode_getsecurity() |
-> cap_inode_getsecurity() |
{ |
0 = make_kuid(0:0:4k /* lower s_user_ns */, 0); |
10000000 = mapped_kuid_fs(0:10000000:65536 /* idmapped mount */, 0); |
10000000 = from_kuid(0:0:4k /* overlayfs idmapping */, 10000000); |
|____________________________________________________________________|
}
-> vfs_getxattr_alloc()
-> handler->get == /* lower filesystem callback */
And if the user chooses option (2) we get:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:10000000:65536
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
-> vfs_getxattr()
-> xattr_getsecurity()
-> security_inode_getsecurity() _______________________________
-> cap_inode_getsecurity() | |
{ V |
10000000 = make_kuid(0:10000000:65536 /* overlayfs idmapping */, 0); |
10000000 = mapped_kuid_fs(0:0:4k /* no idmapped mount */, 10000000); |
/* Expected result is 0 and thus that we own the fscap. */ |
0 = from_kuid(0:10000000:65536 /* caller's idmapping */, 10000000); |
} |
-> vfs_getxattr_alloc() |
-> handler->get == ovl_other_xattr_get() |
|-> vfs_getxattr() |
-> xattr_getsecurity() |
-> security_inode_getsecurity() |
-> cap_inode_getsecurity() |
{ |
0 = make_kuid(0:0:4k /* lower s_user_ns */, 0); |
10000000 = mapped_kuid_fs(0:10000000:65536 /* idmapped mount */, 0); |
0 = from_kuid(0:10000000:65536 /* overlayfs idmapping */, 10000000); |
|____________________________________________________________________|
}
-> vfs_getxattr_alloc()
-> handler->get == /* lower filesystem callback */
We can see how the translation happens correctly in those cases as the
conversion happens within the vfs_getxattr() helper.
For POSIX ACLs we need to do something similar. However, in contrast to fscaps
we cannot apply the fix directly to the kernel internal posix acl data
structure as this would alter the cached values and would also require a rework
of how we currently deal with POSIX ACLs in general which almost never take the
filesystem idmapping into account (the noteable exception being FUSE but even
there the implementation is special) and instead retrieve the raw values based
on the initial idmapping.
The correct values are then generated right before returning to userspace. The
fix for this is to move taking the mount's idmapping into account directly in
vfs_getxattr() instead of having it be part of posix_acl_fix_xattr_to_user().
To this end we split out two small and unexported helpers
posix_acl_getxattr_idmapped_mnt() and posix_acl_setxattr_idmapped_mnt(). The
former to be called in vfs_getxattr() and the latter to be called in
vfs_setxattr().
Let's go back to the original example. Assume the user chose option (1) and
mounted overlayfs on top of idmapped mounts on the host:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:0:4k /* initial idmapping */
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
|> vfs_getxattr()
| |> __vfs_getxattr()
| | -> handler->get == ovl_posix_acl_xattr_get()
| | -> ovl_xattr_get()
| | -> vfs_getxattr()
| | |> __vfs_getxattr()
| | | -> handler->get() /* lower filesystem callback */
| | |> posix_acl_getxattr_idmapped_mnt()
| | {
| | 4 = make_kuid(&init_user_ns, 4);
| | 10000004 = mapped_kuid_fs(0:10000000:65536 /* lower idmapped mount */, 4);
| | 10000004 = from_kuid(&init_user_ns, 10000004);
| | |_______________________
| | } |
| | |
| |> posix_acl_getxattr_idmapped_mnt() |
| { |
| V
| 10000004 = make_kuid(&init_user_ns, 10000004);
| 10000004 = mapped_kuid_fs(&init_user_ns /* no idmapped mount */, 10000004);
| 10000004 = from_kuid(&init_user_ns, 10000004);
| } |_________________________________________________
| |
| |
|> posix_acl_fix_xattr_to_user() |
{ V
10000004 = make_kuid(0:0:4k /* init_user_ns */, 10000004);
/* SUCCESS */
4 = from_kuid(0:10000000:65536 /* caller's idmapping */, 10000004);
}
And similarly if the user chooses option (1) and mounted overayfs on top of
idmapped mounts inside the container:
idmapped mount /vol/contpool/merge: 0:10000000:65536
caller's idmapping: 0:10000000:65536
overlayfs idmapping (ofs->creator_cred): 0:10000000:65536
sys_getxattr()
-> path_getxattr()
-> getxattr()
-> do_getxattr()
|> vfs_getxattr()
| |> __vfs_getxattr()
| | -> handler->get == ovl_posix_acl_xattr_get()
| | -> ovl_xattr_get()
| | -> vfs_getxattr()
| | |> __vfs_getxattr()
| | | -> handler->get() /* lower filesystem callback */
| | |> posix_acl_getxattr_idmapped_mnt()
| | {
| | 4 = make_kuid(&init_user_ns, 4);
| | 10000004 = mapped_kuid_fs(0:10000000:65536 /* lower idmapped mount */, 4);
| | 10000004 = from_kuid(&init_user_ns, 10000004);
| | |_______________________
| | } |
| | |
| |> posix_acl_getxattr_idmapped_mnt() |
| { V
| 10000004 = make_kuid(&init_user_ns, 10000004);
| 10000004 = mapped_kuid_fs(&init_user_ns /* no idmapped mount */, 10000004);
| 10000004 = from_kuid(0(&init_user_ns, 10000004);
| |_________________________________________________
| } |
| |
|> posix_acl_fix_xattr_to_user() |
{ V
10000004 = make_kuid(0:0:4k /* init_user_ns */, 10000004);
/* SUCCESS */
4 = from_kuid(0:10000000:65536 /* caller's idmappings */, 10000004);
}
The last remaining problem we need to fix here is ovl_get_acl(). During
ovl_permission() overlayfs will call:
ovl_permission()
-> generic_permission()
-> acl_permission_check()
-> check_acl()
-> get_acl()
-> inode->i_op->get_acl() == ovl_get_acl()
> get_acl() /* on the underlying filesystem)
->inode->i_op->get_acl() == /*lower filesystem callback */
-> posix_acl_permission()
passing through the get_acl request to the underlying filesystem. This will
retrieve the acls stored in the lower filesystem without taking the idmapping
of the underlying mount into account as this would mean altering the cached
values for the lower filesystem. So we block using ACLs for now until we
decided on a nice way to fix this. Note this limitation both in the
documentation and in the code.
The most straightforward solution would be to have ovl_get_acl() simply
duplicate the ACLs, update the values according to the idmapped mount and
return it to acl_permission_check() so it can be used in posix_acl_permission()
forgetting them afterwards. This is a bit heavy handed but fairly
straightforward otherwise.
Link: https://github.com/brauner/mount-idmapped/issues/9
Link: https://lore.kernel.org/r/20220708090134.385160-2-brauner@kernel.org
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: linux-unionfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
689 lines
23 KiB
C
689 lines
23 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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*
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* Copyright (C) 2011 Novell Inc.
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*/
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#include <linux/kernel.h>
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#include <linux/uuid.h>
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include "ovl_entry.h"
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#undef pr_fmt
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#define pr_fmt(fmt) "overlayfs: " fmt
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enum ovl_path_type {
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__OVL_PATH_UPPER = (1 << 0),
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__OVL_PATH_MERGE = (1 << 1),
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__OVL_PATH_ORIGIN = (1 << 2),
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};
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#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
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#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
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#define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN)
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#define OVL_XATTR_NAMESPACE "overlay."
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#define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
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#define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
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enum ovl_xattr {
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OVL_XATTR_OPAQUE,
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OVL_XATTR_REDIRECT,
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OVL_XATTR_ORIGIN,
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OVL_XATTR_IMPURE,
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OVL_XATTR_NLINK,
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OVL_XATTR_UPPER,
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OVL_XATTR_METACOPY,
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OVL_XATTR_PROTATTR,
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};
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enum ovl_inode_flag {
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/* Pure upper dir that may contain non pure upper entries */
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OVL_IMPURE,
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/* Non-merge dir that may contain whiteout entries */
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OVL_WHITEOUTS,
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OVL_INDEX,
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OVL_UPPERDATA,
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/* Inode number will remain constant over copy up. */
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OVL_CONST_INO,
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};
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enum ovl_entry_flag {
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OVL_E_UPPER_ALIAS,
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OVL_E_OPAQUE,
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OVL_E_CONNECTED,
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};
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enum {
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OVL_XINO_OFF,
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OVL_XINO_AUTO,
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OVL_XINO_ON,
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};
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/*
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* The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
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* where:
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* origin.fh - exported file handle of the lower file
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* origin.uuid - uuid of the lower filesystem
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*/
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#define OVL_FH_VERSION 0
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#define OVL_FH_MAGIC 0xfb
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/* CPU byte order required for fid decoding: */
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#define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
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#define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
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/* Is the real inode encoded in fid an upper inode? */
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#define OVL_FH_FLAG_PATH_UPPER (1 << 2)
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#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
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OVL_FH_FLAG_PATH_UPPER)
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#if defined(__LITTLE_ENDIAN)
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#define OVL_FH_FLAG_CPU_ENDIAN 0
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#elif defined(__BIG_ENDIAN)
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#define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
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#else
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#error Endianness not defined
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#endif
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/* The type used to be returned by overlay exportfs for misaligned fid */
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#define OVL_FILEID_V0 0xfb
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/* The type returned by overlay exportfs for 32bit aligned fid */
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#define OVL_FILEID_V1 0xf8
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/* On-disk format for "origin" file handle */
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struct ovl_fb {
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u8 version; /* 0 */
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u8 magic; /* 0xfb */
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u8 len; /* size of this header + size of fid */
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u8 flags; /* OVL_FH_FLAG_* */
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u8 type; /* fid_type of fid */
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uuid_t uuid; /* uuid of filesystem */
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u32 fid[]; /* file identifier should be 32bit aligned in-memory */
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} __packed;
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/* In-memory and on-wire format for overlay file handle */
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struct ovl_fh {
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u8 padding[3]; /* make sure fb.fid is 32bit aligned */
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union {
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struct ovl_fb fb;
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u8 buf[0];
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};
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} __packed;
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#define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
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#define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
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#define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
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offsetof(struct ovl_fb, fid))
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extern const char *const ovl_xattr_table[][2];
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static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
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{
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return ovl_xattr_table[ox][ofs->config.userxattr];
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}
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/*
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* When changing ownership of an upper object map the intended ownership
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* according to the upper layer's idmapping. When an upper mount idmaps files
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* that are stored on-disk as owned by id 1001 to id 1000 this means stat on
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* this object will report it as being owned by id 1000 when calling stat via
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* the upper mount.
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* In order to change ownership of an object so stat reports id 1000 when
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* called on an idmapped upper mount the value written to disk - i.e., the
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* value stored in ia_*id - must 1001. The mount mapping helper will thus take
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* care to map 1000 to 1001.
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* The mnt idmapping helpers are nops if the upper layer isn't idmapped.
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*/
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static inline int ovl_do_notify_change(struct ovl_fs *ofs,
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struct dentry *upperdentry,
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struct iattr *attr)
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{
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return notify_change(ovl_upper_mnt_userns(ofs), upperdentry, attr, NULL);
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}
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static inline int ovl_do_rmdir(struct ovl_fs *ofs,
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struct inode *dir, struct dentry *dentry)
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{
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int err = vfs_rmdir(ovl_upper_mnt_userns(ofs), dir, dentry);
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pr_debug("rmdir(%pd2) = %i\n", dentry, err);
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return err;
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}
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static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir,
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struct dentry *dentry)
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{
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int err = vfs_unlink(ovl_upper_mnt_userns(ofs), dir, dentry, NULL);
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pr_debug("unlink(%pd2) = %i\n", dentry, err);
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return err;
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}
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static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry,
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struct inode *dir, struct dentry *new_dentry)
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{
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int err = vfs_link(old_dentry, ovl_upper_mnt_userns(ofs), dir, new_dentry, NULL);
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pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
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return err;
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}
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static inline int ovl_do_create(struct ovl_fs *ofs,
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struct inode *dir, struct dentry *dentry,
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umode_t mode)
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{
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int err = vfs_create(ovl_upper_mnt_userns(ofs), dir, dentry, mode, true);
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pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
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return err;
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}
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static inline int ovl_do_mkdir(struct ovl_fs *ofs,
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struct inode *dir, struct dentry *dentry,
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umode_t mode)
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{
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int err = vfs_mkdir(ovl_upper_mnt_userns(ofs), dir, dentry, mode);
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pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
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return err;
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}
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static inline int ovl_do_mknod(struct ovl_fs *ofs,
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struct inode *dir, struct dentry *dentry,
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umode_t mode, dev_t dev)
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{
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int err = vfs_mknod(ovl_upper_mnt_userns(ofs), dir, dentry, mode, dev);
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pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
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return err;
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}
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static inline int ovl_do_symlink(struct ovl_fs *ofs,
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struct inode *dir, struct dentry *dentry,
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const char *oldname)
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{
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int err = vfs_symlink(ovl_upper_mnt_userns(ofs), dir, dentry, oldname);
|
|
|
|
pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
|
|
return err;
|
|
}
|
|
|
|
static inline ssize_t ovl_do_getxattr(struct path *path, const char *name,
|
|
void *value, size_t size)
|
|
{
|
|
int err, len;
|
|
|
|
WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
|
|
|
|
err = vfs_getxattr(mnt_user_ns(path->mnt), path->dentry,
|
|
name, value, size);
|
|
len = (value && err > 0) ? err : 0;
|
|
|
|
pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
|
|
path->dentry, name, min(len, 48), value, size, err);
|
|
return err;
|
|
}
|
|
|
|
static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
|
|
struct dentry *upperdentry,
|
|
enum ovl_xattr ox, void *value,
|
|
size_t size)
|
|
{
|
|
struct path upperpath = {
|
|
.dentry = upperdentry,
|
|
.mnt = ovl_upper_mnt(ofs),
|
|
};
|
|
|
|
return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size);
|
|
}
|
|
|
|
static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
|
|
struct path *path,
|
|
enum ovl_xattr ox, void *value,
|
|
size_t size)
|
|
{
|
|
return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size);
|
|
}
|
|
|
|
static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
|
|
const char *name, const void *value,
|
|
size_t size, int flags)
|
|
{
|
|
int err = vfs_setxattr(ovl_upper_mnt_userns(ofs), dentry, name,
|
|
(void *)value, size, flags);
|
|
|
|
pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
|
|
dentry, name, min((int)size, 48), value, size, flags, err);
|
|
return err;
|
|
}
|
|
|
|
static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
|
|
enum ovl_xattr ox, const void *value,
|
|
size_t size)
|
|
{
|
|
return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
|
|
}
|
|
|
|
static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
|
|
const char *name)
|
|
{
|
|
int err = vfs_removexattr(ovl_upper_mnt_userns(ofs), dentry, name);
|
|
pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
|
|
return err;
|
|
}
|
|
|
|
static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
|
|
enum ovl_xattr ox)
|
|
{
|
|
return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
|
|
}
|
|
|
|
static inline int ovl_do_rename(struct ovl_fs *ofs, struct inode *olddir,
|
|
struct dentry *olddentry, struct inode *newdir,
|
|
struct dentry *newdentry, unsigned int flags)
|
|
{
|
|
int err;
|
|
struct renamedata rd = {
|
|
.old_mnt_userns = ovl_upper_mnt_userns(ofs),
|
|
.old_dir = olddir,
|
|
.old_dentry = olddentry,
|
|
.new_mnt_userns = ovl_upper_mnt_userns(ofs),
|
|
.new_dir = newdir,
|
|
.new_dentry = newdentry,
|
|
.flags = flags,
|
|
};
|
|
|
|
pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
|
|
err = vfs_rename(&rd);
|
|
if (err) {
|
|
pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
|
|
olddentry, newdentry, err);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static inline int ovl_do_whiteout(struct ovl_fs *ofs,
|
|
struct inode *dir, struct dentry *dentry)
|
|
{
|
|
int err = vfs_whiteout(ovl_upper_mnt_userns(ofs), dir, dentry);
|
|
pr_debug("whiteout(%pd2) = %i\n", dentry, err);
|
|
return err;
|
|
}
|
|
|
|
static inline struct dentry *ovl_do_tmpfile(struct ovl_fs *ofs,
|
|
struct dentry *dentry, umode_t mode)
|
|
{
|
|
struct dentry *ret = vfs_tmpfile(ovl_upper_mnt_userns(ofs), dentry, mode, 0);
|
|
int err = PTR_ERR_OR_ZERO(ret);
|
|
|
|
pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
|
|
return ret;
|
|
}
|
|
|
|
static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
|
|
const char *name,
|
|
struct dentry *base, int len)
|
|
{
|
|
return lookup_one(ovl_upper_mnt_userns(ofs), name, base, len);
|
|
}
|
|
|
|
static inline bool ovl_open_flags_need_copy_up(int flags)
|
|
{
|
|
if (!flags)
|
|
return false;
|
|
|
|
return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
|
|
}
|
|
|
|
static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
|
|
{
|
|
/*
|
|
* To avoid regressions in existing setups with overlay lower offline
|
|
* changes, we allow lower changes only if none of the new features
|
|
* are used.
|
|
*/
|
|
return (!ofs->config.index && !ofs->config.metacopy &&
|
|
!ofs->config.redirect_dir && ofs->config.xino != OVL_XINO_ON);
|
|
}
|
|
|
|
|
|
/* util.c */
|
|
int ovl_want_write(struct dentry *dentry);
|
|
void ovl_drop_write(struct dentry *dentry);
|
|
struct dentry *ovl_workdir(struct dentry *dentry);
|
|
const struct cred *ovl_override_creds(struct super_block *sb);
|
|
int ovl_can_decode_fh(struct super_block *sb);
|
|
struct dentry *ovl_indexdir(struct super_block *sb);
|
|
bool ovl_index_all(struct super_block *sb);
|
|
bool ovl_verify_lower(struct super_block *sb);
|
|
struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
|
|
bool ovl_dentry_remote(struct dentry *dentry);
|
|
void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
|
|
unsigned int mask);
|
|
bool ovl_dentry_weird(struct dentry *dentry);
|
|
enum ovl_path_type ovl_path_type(struct dentry *dentry);
|
|
void ovl_path_upper(struct dentry *dentry, struct path *path);
|
|
void ovl_path_lower(struct dentry *dentry, struct path *path);
|
|
void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
|
|
void ovl_i_path_real(struct inode *inode, struct path *path);
|
|
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
|
|
enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
|
|
struct dentry *ovl_dentry_upper(struct dentry *dentry);
|
|
struct dentry *ovl_dentry_lower(struct dentry *dentry);
|
|
struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
|
|
const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
|
|
const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
|
|
struct dentry *ovl_dentry_real(struct dentry *dentry);
|
|
struct dentry *ovl_i_dentry_upper(struct inode *inode);
|
|
struct inode *ovl_inode_upper(struct inode *inode);
|
|
struct inode *ovl_inode_lower(struct inode *inode);
|
|
struct inode *ovl_inode_lowerdata(struct inode *inode);
|
|
struct inode *ovl_inode_real(struct inode *inode);
|
|
struct inode *ovl_inode_realdata(struct inode *inode);
|
|
struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
|
|
void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
|
|
void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
|
|
void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
|
|
bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
|
|
bool ovl_dentry_is_opaque(struct dentry *dentry);
|
|
bool ovl_dentry_is_whiteout(struct dentry *dentry);
|
|
void ovl_dentry_set_opaque(struct dentry *dentry);
|
|
bool ovl_dentry_has_upper_alias(struct dentry *dentry);
|
|
void ovl_dentry_set_upper_alias(struct dentry *dentry);
|
|
bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
|
|
bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
|
|
bool ovl_has_upperdata(struct inode *inode);
|
|
void ovl_set_upperdata(struct inode *inode);
|
|
bool ovl_redirect_dir(struct super_block *sb);
|
|
const char *ovl_dentry_get_redirect(struct dentry *dentry);
|
|
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
|
|
void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
|
|
void ovl_dir_modified(struct dentry *dentry, bool impurity);
|
|
u64 ovl_dentry_version_get(struct dentry *dentry);
|
|
bool ovl_is_whiteout(struct dentry *dentry);
|
|
struct file *ovl_path_open(struct path *path, int flags);
|
|
int ovl_copy_up_start(struct dentry *dentry, int flags);
|
|
void ovl_copy_up_end(struct dentry *dentry);
|
|
bool ovl_already_copied_up(struct dentry *dentry, int flags);
|
|
bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, struct path *path,
|
|
enum ovl_xattr ox);
|
|
bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, struct path *path);
|
|
|
|
static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
|
|
struct dentry *upperdentry)
|
|
{
|
|
struct path upperpath = {
|
|
.dentry = upperdentry,
|
|
.mnt = ovl_upper_mnt(ofs),
|
|
};
|
|
return ovl_path_check_origin_xattr(ofs, &upperpath);
|
|
}
|
|
|
|
int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
|
|
enum ovl_xattr ox, const void *value, size_t size,
|
|
int xerr);
|
|
int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
|
|
bool ovl_inuse_trylock(struct dentry *dentry);
|
|
void ovl_inuse_unlock(struct dentry *dentry);
|
|
bool ovl_is_inuse(struct dentry *dentry);
|
|
bool ovl_need_index(struct dentry *dentry);
|
|
int ovl_nlink_start(struct dentry *dentry);
|
|
void ovl_nlink_end(struct dentry *dentry);
|
|
int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
|
|
int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct path *path);
|
|
bool ovl_is_metacopy_dentry(struct dentry *dentry);
|
|
char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct path *path, int padding);
|
|
int ovl_sync_status(struct ovl_fs *ofs);
|
|
|
|
static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
|
|
{
|
|
set_bit(flag, &OVL_I(inode)->flags);
|
|
}
|
|
|
|
static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
|
|
{
|
|
clear_bit(flag, &OVL_I(inode)->flags);
|
|
}
|
|
|
|
static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
|
|
{
|
|
return test_bit(flag, &OVL_I(inode)->flags);
|
|
}
|
|
|
|
static inline bool ovl_is_impuredir(struct super_block *sb,
|
|
struct dentry *upperdentry)
|
|
{
|
|
struct ovl_fs *ofs = OVL_FS(sb);
|
|
struct path upperpath = {
|
|
.dentry = upperdentry,
|
|
.mnt = ovl_upper_mnt(ofs),
|
|
};
|
|
|
|
return ovl_path_check_dir_xattr(ofs, &upperpath, OVL_XATTR_IMPURE);
|
|
}
|
|
|
|
/*
|
|
* With xino=auto, we do best effort to keep all inodes on same st_dev and
|
|
* d_ino consistent with st_ino.
|
|
* With xino=on, we do the same effort but we warn if we failed.
|
|
*/
|
|
static inline bool ovl_xino_warn(struct super_block *sb)
|
|
{
|
|
return OVL_FS(sb)->config.xino == OVL_XINO_ON;
|
|
}
|
|
|
|
/* All layers on same fs? */
|
|
static inline bool ovl_same_fs(struct super_block *sb)
|
|
{
|
|
return OVL_FS(sb)->xino_mode == 0;
|
|
}
|
|
|
|
/* All overlay inodes have same st_dev? */
|
|
static inline bool ovl_same_dev(struct super_block *sb)
|
|
{
|
|
return OVL_FS(sb)->xino_mode >= 0;
|
|
}
|
|
|
|
static inline unsigned int ovl_xino_bits(struct super_block *sb)
|
|
{
|
|
return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
|
|
}
|
|
|
|
static inline void ovl_inode_lock(struct inode *inode)
|
|
{
|
|
mutex_lock(&OVL_I(inode)->lock);
|
|
}
|
|
|
|
static inline int ovl_inode_lock_interruptible(struct inode *inode)
|
|
{
|
|
return mutex_lock_interruptible(&OVL_I(inode)->lock);
|
|
}
|
|
|
|
static inline void ovl_inode_unlock(struct inode *inode)
|
|
{
|
|
mutex_unlock(&OVL_I(inode)->lock);
|
|
}
|
|
|
|
|
|
/* namei.c */
|
|
int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
|
|
|
|
static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
|
|
{
|
|
if (fh_len < sizeof(struct ovl_fh))
|
|
return -EINVAL;
|
|
|
|
return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
|
|
}
|
|
|
|
struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
|
|
struct vfsmount *mnt, bool connected);
|
|
int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
|
|
struct dentry *upperdentry, struct ovl_path **stackp);
|
|
int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
|
|
enum ovl_xattr ox, struct dentry *real, bool is_upper,
|
|
bool set);
|
|
struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
|
|
int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
|
|
int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
|
|
struct qstr *name);
|
|
struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
|
|
struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
|
|
struct dentry *origin, bool verify);
|
|
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
|
|
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
|
|
unsigned int flags);
|
|
bool ovl_lower_positive(struct dentry *dentry);
|
|
|
|
static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
|
|
struct dentry *origin, bool set)
|
|
{
|
|
return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
|
|
false, set);
|
|
}
|
|
|
|
static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
|
|
struct dentry *upper, bool set)
|
|
{
|
|
return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
|
|
}
|
|
|
|
/* readdir.c */
|
|
extern const struct file_operations ovl_dir_operations;
|
|
struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
|
|
int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
|
|
void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
|
|
struct list_head *list);
|
|
void ovl_cache_free(struct list_head *list);
|
|
void ovl_dir_cache_free(struct inode *inode);
|
|
int ovl_check_d_type_supported(struct path *realpath);
|
|
int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
|
|
struct vfsmount *mnt, struct dentry *dentry, int level);
|
|
int ovl_indexdir_cleanup(struct ovl_fs *ofs);
|
|
|
|
/*
|
|
* Can we iterate real dir directly?
|
|
*
|
|
* Non-merge dir may contain whiteouts from a time it was a merge upper, before
|
|
* lower dir was removed under it and possibly before it was rotated from upper
|
|
* to lower layer.
|
|
*/
|
|
static inline bool ovl_dir_is_real(struct dentry *dir)
|
|
{
|
|
return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
|
|
}
|
|
|
|
/* inode.c */
|
|
int ovl_set_nlink_upper(struct dentry *dentry);
|
|
int ovl_set_nlink_lower(struct dentry *dentry);
|
|
unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
|
|
struct dentry *upperdentry,
|
|
unsigned int fallback);
|
|
int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
|
|
struct iattr *attr);
|
|
int ovl_getattr(struct user_namespace *mnt_userns, const struct path *path,
|
|
struct kstat *stat, u32 request_mask, unsigned int flags);
|
|
int ovl_permission(struct user_namespace *mnt_userns, struct inode *inode,
|
|
int mask);
|
|
int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
|
|
const void *value, size_t size, int flags);
|
|
int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
|
|
void *value, size_t size);
|
|
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
|
|
struct posix_acl *ovl_get_acl(struct inode *inode, int type, bool rcu);
|
|
int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
|
|
bool ovl_is_private_xattr(struct super_block *sb, const char *name);
|
|
|
|
struct ovl_inode_params {
|
|
struct inode *newinode;
|
|
struct dentry *upperdentry;
|
|
struct ovl_path *lowerpath;
|
|
bool index;
|
|
unsigned int numlower;
|
|
char *redirect;
|
|
struct dentry *lowerdata;
|
|
};
|
|
void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
|
|
unsigned long ino, int fsid);
|
|
struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
|
|
struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
|
|
bool is_upper);
|
|
bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
|
|
struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
|
|
struct inode *ovl_get_inode(struct super_block *sb,
|
|
struct ovl_inode_params *oip);
|
|
void ovl_copyattr(struct inode *to);
|
|
|
|
/* vfs inode flags copied from real to ovl inode */
|
|
#define OVL_COPY_I_FLAGS_MASK (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE)
|
|
/* vfs inode flags read from overlay.protattr xattr to ovl inode */
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#define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE)
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/*
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* fileattr flags copied from lower to upper inode on copy up.
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* We cannot copy up immutable/append-only flags, because that would prevent
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* linking temp inode to upper dir, so we store them in xattr instead.
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*/
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#define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL)
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#define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
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#define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL)
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#define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
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void ovl_check_protattr(struct inode *inode, struct dentry *upper);
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int ovl_set_protattr(struct inode *inode, struct dentry *upper,
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struct fileattr *fa);
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static inline void ovl_copyflags(struct inode *from, struct inode *to)
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{
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unsigned int mask = OVL_COPY_I_FLAGS_MASK;
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inode_set_flags(to, from->i_flags & mask, mask);
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}
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/* dir.c */
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extern const struct inode_operations ovl_dir_inode_operations;
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int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
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struct dentry *dentry);
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struct ovl_cattr {
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dev_t rdev;
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umode_t mode;
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const char *link;
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struct dentry *hardlink;
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};
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#define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
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int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir,
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struct dentry **newdentry, umode_t mode);
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struct dentry *ovl_create_real(struct ovl_fs *ofs,
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struct inode *dir, struct dentry *newdentry,
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struct ovl_cattr *attr);
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int ovl_cleanup(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry);
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struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir);
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struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
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struct ovl_cattr *attr);
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/* file.c */
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extern const struct file_operations ovl_file_operations;
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int __init ovl_aio_request_cache_init(void);
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void ovl_aio_request_cache_destroy(void);
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int ovl_real_fileattr_get(struct path *realpath, struct fileattr *fa);
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int ovl_real_fileattr_set(struct path *realpath, struct fileattr *fa);
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int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
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int ovl_fileattr_set(struct user_namespace *mnt_userns,
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struct dentry *dentry, struct fileattr *fa);
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/* copy_up.c */
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int ovl_copy_up(struct dentry *dentry);
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int ovl_copy_up_with_data(struct dentry *dentry);
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int ovl_maybe_copy_up(struct dentry *dentry, int flags);
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int ovl_copy_xattr(struct super_block *sb, struct path *path, struct dentry *new);
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int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
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struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
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bool is_upper);
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int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
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struct dentry *upper);
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/* export.c */
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extern const struct export_operations ovl_export_operations;
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