Re: [PATCH v5 00/42] idmapped mounts

Darrick J. Wong
2021-01-14T17:13:40Z

On Tue, Jan 12, 2021 at 11:00:42PM +0100, Christian Brauner wrote:
> Hey everyone,
>
> The only major change is the inclusion of hch's patch to port XFS to
> support idmapped mounts. Thanks to Christoph for doing that work.

Yay :)

> (For a full list of major changes between versions see the end of this
> cover letter.
> Please also note the large xfstests testsuite in patch 42 that has been
> kept as part of this series. It verifies correct vfs behavior with and
> without idmapped mounts including covering newer vfs features such as
> io_uring.
> I currently still plan to target the v5.12 merge window.)
>
> With this patchset we make it possible to attach idmappings to mounts,
> i.e. simply put different bind mounts can expose the same file or
> directory with different ownership.
> Shifting of ownership on a per-mount basis handles a wide range of
> long standing use-cases. Here are just a few:
> - Shifting of a subset of ownership-less filesystems (vfat) for use by
> multiple users, effectively allowing for DAC on such devices
> (systemd, Android, ...)
> - Allow remapping uid/gid on external filesystems or paths (USB sticks,
> network filesystem, ...) to match the local system's user and groups.
> (David Howells intends to port AFS as a first candidate.)
> - Shifting of a container rootfs or base image without having to mangle
> every file (runc, Docker, containerd, k8s, LXD, systemd ...)
> - Sharing of data between host or privileged containers with
> unprivileged containers (runC, Docker, containerd, k8s, LXD, ...)
> - Data sharing between multiple user namespaces with incompatible maps
> (LXD, k8s, ...)

That sounds neat. AFAICT, the VFS passes the filesystem a mount userns
structure, which is then carried down the call stack to whatever
functions actually care about mapping kernel [ug]ids to their ondisk
versions?

Does quota still work after this patchset is applied? There isn't any
mention of that in the cover letter and I don't see a code patch, so
does that mean everything just works? I'm particularly curious about
whether there can exist processes with CAP_SYS_ADMIN and an idmapped
mount? Syscalls like bulkstat and quotactl present file [ug]ids to
programs, but afaict there won't be any translating going on?

(To be fair, bulkstat is an xfs-only thing, but quota control isn't.)

I'll start skimming the patchset...

--D

>
> There has been significant interest in this patchset as evidenced by
> user commenting on previous version of this patchset. They include
> containerd, ChromeOS, systemd, LXD and a range of others. There is
> already a patchset up for containerd, the default Kubernetes container
> runtime https://github.com/containerd/containerd/pull/4734
> to make use of this. systemd intends to use it in their systemd-homed
> implementation for portable home directories. ChromeOS wants to make use
> of it to share data between the host and the Linux containers they run
> on Chrome- and Pixelbooks.
> (Fwiw, for fun and since I wanted to do this for a long time I've ported
> my home directory to be completely portable with a simple service file
> that now mounts my home directory on an ext4 formatted usb stick with
> an id mapping mapping all files to the random uid I'm assigned at
> login.)
>
> Making it possible to share directories and mounts between users with
> different uids and gids is itself quite an important use-case in
> distributed systems environments. It's of course especially useful in
> general for portable usb sticks, sharing data between multiple users in,
> and sharing home directories between multiple users. The last example is
> now elegantly expressed in systemd's homed concept for portable home
> directories. As mentioned above, idmapped mounts also allow data from
> the host to be shared with unprivileged containers, between privileged
> and unprivileged containers simultaneously and in addition also between
> unprivileged containers with different idmappings whenever they are used
> to isolate one container completely from another container.
>
> We have implemented and proposed multiple solutions to this before. This
> included the introduction of fsid mappings, a tiny filesystem I've
> authored with Seth Forshee that is currently carried in Ubuntu that has
> shown to be the wrong approach, and the conceptual hack of calling
> override creds directly in the vfs. In addition, to some of these
> solutions being hacky none of these solutions have covered all of the
> above use-cases.
>
> Idmappings become a property of struct vfsmount instead of tying it to a
> process being inside of a user namespace which has been the case for all
> other proposed approaches. It also allows to pass down the user
> namespace into the filesystems which is a clean way instead of violating
> calling conventions by strapping the user namespace information that is
> a property of the mount to the caller's credentials or similar hacks.
> Each mount can have a separate idmapping and idmapped mounts can even be
> created in the initial user namespace unblocking a range of use-cases.
>
> To this end the vfsmount struct gains a new struct user_namespace
> member. The idmapping of the user namespace becomes the idmapping of the
> mount. A caller that is privileged with respect to the user namespace of
> the superblock of the underlying filesystem can create an idmapped
> mount. In the future, we can enable unprivileged use-cases by checking
> whether the caller is privileged wrt to the user namespace that an
> already idmapped mount has been marked with, allowing them to change the
> idmapping. For now, keep things simple until the need arises.
> Note, that with syscall interception it is already possible to intercept
> idmapped mount requests from unprivileged containers and handle them in
> a sufficiently privileged container manager. Support for this is already
> available in LXD and will be available in runC where syscall
> interception is currently in the process of becoming part of the runtime
> spec: https://github.com/opencontainers/runtime-spec/pull/1074.
>
> 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. By default vfsmounts are marked with the initial
> user namespace and no behavioral or performance changes are observed.
> All mapping operations are nops for the initial user namespace. When a
> file/inode is accessed through an idmapped mount the i_uid and i_gid of
> the inode will be remapped according to the user namespace the mount has
> been marked with.
>
> In order to support idmapped mounts, filesystems need to be changed and
> mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The initial
> version contains fat, ext4, and xfs including a list of examples.
> But patches for other filesystems are actively worked on and will be
> sent out separately. We are here to see this through and there are
> multiple people involved in converting filesystems. So filesystem
> developers are not left alone with this and are provided with a large
> testsuite to verify that their port is correct.
>
> 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. Here are a few
> illustrations:
>
> 1. Create a simple idmapped mount of another user's home directory
>
> u1001@f2-vm:/$ sudo ./mount-idmapped --map-mount b: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--
>
> 2. Create mapping of the whole ext4 rootfs without a mapping for uid and gid 0
>
> ubuntu@f2-vm:~$ sudo /mount-idmapped --map-mount b:1:1:65536 / /mnt/
> ubuntu@f2-vm:~$ findmnt | grep mnt
> └─/mnt /dev/sda2 ext4 rw,relatime
> └─/mnt/mnt /dev/sda2 ext4 rw,relatime
> ubuntu@f2-vm:~$ sudo mkdir /AS-ROOT-CAN-CREATE
> ubuntu@f2-vm:~$ sudo mkdir /mnt/AS-ROOT-CANT-CREATE
> mkdir: cannot create directory ‘/mnt/AS-ROOT-CANT-CREATE’: Value too large for defined data type
> ubuntu@f2-vm:~$ mkdir /mnt/home/ubuntu/AS-USER-1000-CAN-CREATE
>
> 3. Create a vfat usb mount and expose to user 1001 and 5000
>
> ubuntu@f2-vm:/$ sudo mount /dev/sdb /mnt
> ubuntu@f2-vm:/$ findmnt | grep mnt
> └─/mnt /dev/sdb vfat rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro
> ubuntu@f2-vm:/$ ls -al /mnt
> total 12
> drwxr-xr-x 2 root root 4096 Jan 1 1970 .
> drwxr-xr-x 34 root root 4096 Oct 28 22:24 ..
> -rwxr-xr-x 1 root root 4 Oct 28 03:44 aaa
> -rwxr-xr-x 1 root root 0 Oct 28 01:09 bbb
> ubuntu@f2-vm:/$ sudo /mount-idmapped --map-mount b:0:1001:1 /mnt /mnt-1001/
> ubuntu@f2-vm:/$ ls -al /mnt-1001/
> total 12
> drwxr-xr-x 2 u1001 u1001 4096 Jan 1 1970 .
> drwxr-xr-x 34 root root 4096 Oct 28 22:24 ..
> -rwxr-xr-x 1 u1001 u1001 4 Oct 28 03:44 aaa
> -rwxr-xr-x 1 u1001 u1001 0 Oct 28 01:09 bbb
> ubuntu@f2-vm:/$ sudo /mount-idmapped --map-mount b:0:5000:1 /mnt /mnt-5000/
> ubuntu@f2-vm:/$ ls -al /mnt-5000/
> total 12
> drwxr-xr-x 2 5000 5000 4096 Jan 1 1970 .
> drwxr-xr-x 34 root root 4096 Oct 28 22:24 ..
> -rwxr-xr-x 1 5000 5000 4 Oct 28 03:44 aaa
> -rwxr-xr-x 1 5000 5000 0 Oct 28 01:09 bbb
>
> 4. Create an idmapped rootfs mount for a container
>
> root@f2-vm:~# ls -al /var/lib/lxc/f2/rootfs/
> total 68
> drwxr-xr-x 17 20000 20000 4096 Sep 24 07:48 .
> drwxrwx--- 3 20000 20000 4096 Oct 16 19:26 ..
> lrwxrwxrwx 1 20000 20000 7 Sep 24 07:43 bin -> usr/bin
> drwxr-xr-x 2 20000 20000 4096 Apr 15 2020 boot
> drwxr-xr-x 3 20000 20000 4096 Oct 16 19:26 dev
> drwxr-xr-x 61 20000 20000 4096 Oct 16 19:26 etc
> drwxr-xr-x 3 20000 20000 4096 Sep 24 07:45 home
> lrwxrwxrwx 1 20000 20000 7 Sep 24 07:43 lib -> usr/lib
> lrwxrwxrwx 1 20000 20000 9 Sep 24 07:43 lib32 -> usr/lib32
> lrwxrwxrwx 1 20000 20000 9 Sep 24 07:43 lib64 -> usr/lib64
> lrwxrwxrwx 1 20000 20000 10 Sep 24 07:43 libx32 -> usr/libx32
> drwxr-xr-x 2 20000 20000 4096 Sep 24 07:43 media
> drwxr-xr-x 2 20000 20000 4096 Sep 24 07:43 mnt
> drwxr-xr-x 2 20000 20000 4096 Sep 24 07:43 opt
> drwxr-xr-x 2 20000 20000 4096 Apr 15 2020 proc
> drwx------ 2 20000 20000 4096 Sep 24 07:43 root
> drwxr-xr-x 2 20000 20000 4096 Sep 24 07:45 run
> lrwxrwxrwx 1 20000 20000 8 Sep 24 07:43 sbin -> usr/sbin
> drwxr-xr-x 2 20000 20000 4096 Sep 24 07:43 srv
> drwxr-xr-x 2 20000 20000 4096 Apr 15 2020 sys
> drwxrwxrwt 2 20000 20000 4096 Sep 24 07:44 tmp
> drwxr-xr-x 13 20000 20000 4096 Sep 24 07:43 usr
> drwxr-xr-x 12 20000 20000 4096 Sep 24 07:44 var
> root@f2-vm:~# /mount-idmapped --map-mount b:20000:10000:100000 /var/lib/lxc/f2/rootfs/ /mnt
> root@f2-vm:~# ls -al /mnt
> total 68
> drwxr-xr-x 17 10000 10000 4096 Sep 24 07:48 .
> drwxr-xr-x 34 root root 4096 Oct 28 22:24 ..
> lrwxrwxrwx 1 10000 10000 7 Sep 24 07:43 bin -> usr/bin
> drwxr-xr-x 2 10000 10000 4096 Apr 15 2020 boot
> drwxr-xr-x 3 10000 10000 4096 Oct 16 19:26 dev
> drwxr-xr-x 61 10000 10000 4096 Oct 16 19:26 etc
> drwxr-xr-x 3 10000 10000 4096 Sep 24 07:45 home
> lrwxrwxrwx 1 10000 10000 7 Sep 24 07:43 lib -> usr/lib
> lrwxrwxrwx 1 10000 10000 9 Sep 24 07:43 lib32 -> usr/lib32
> lrwxrwxrwx 1 10000 10000 9 Sep 24 07:43 lib64 -> usr/lib64
> lrwxrwxrwx 1 10000 10000 10 Sep 24 07:43 libx32 -> usr/libx32
> drwxr-xr-x 2 10000 10000 4096 Sep 24 07:43 media
> drwxr-xr-x 2 10000 10000 4096 Sep 24 07:43 mnt
> drwxr-xr-x 2 10000 10000 4096 Sep 24 07:43 opt
> drwxr-xr-x 2 10000 10000 4096 Apr 15 2020 proc
> drwx------ 2 10000 10000 4096 Sep 24 07:43 root
> drwxr-xr-x 2 10000 10000 4096 Sep 24 07:45 run
> lrwxrwxrwx 1 10000 10000 8 Sep 24 07:43 sbin -> usr/sbin
> drwxr-xr-x 2 10000 10000 4096 Sep 24 07:43 srv
> drwxr-xr-x 2 10000 10000 4096 Apr 15 2020 sys
> drwxrwxrwt 2 10000 10000 4096 Sep 24 07:44 tmp
> drwxr-xr-x 13 10000 10000 4096 Sep 24 07:43 usr
> drwxr-xr-x 12 10000 10000 4096 Sep 24 07:44 var
> root@f2-vm:~# lxc-start f2 # uses /mnt as rootfs
> root@f2-vm:~# lxc-attach f2 -- cat /proc/1/uid_map
> 0 10000 10000
> root@f2-vm:~# lxc-attach f2 -- cat /proc/1/gid_map
> 0 10000 10000
> root@f2-vm:~# lxc-attach f2 -- ls -al /
> total 52
> drwxr-xr-x 17 root root 4096 Sep 24 07:48 .
> drwxr-xr-x 17 root root 4096 Sep 24 07:48 ..
> lrwxrwxrwx 1 root root 7 Sep 24 07:43 bin -> usr/bin
> drwxr-xr-x 2 root root 4096 Apr 15 2020 boot
> drwxr-xr-x 5 root root 500 Oct 28 23:39 dev
> drwxr-xr-x 61 root root 4096 Oct 28 23:39 etc
> drwxr-xr-x 3 root root 4096 Sep 24 07:45 home
> lrwxrwxrwx 1 root root 7 Sep 24 07:43 lib -> usr/lib
> lrwxrwxrwx 1 root root 9 Sep 24 07:43 lib32 -> usr/lib32
> lrwxrwxrwx 1 root root 9 Sep 24 07:43 lib64 -> usr/lib64
> lrwxrwxrwx 1 root root 10 Sep 24 07:43 libx32 -> usr/libx32
> drwxr-xr-x 2 root root 4096 Sep 24 07:43 media
> drwxr-xr-x 2 root root 4096 Sep 24 07:43 mnt
> drwxr-xr-x 2 root root 4096 Sep 24 07:43 opt
> dr-xr-xr-x 232 nobody nogroup 0 Oct 28 23:39 proc
> drwx------ 2 root root 4096 Oct 28 23:41 root
> drwxr-xr-x 12 root root 360 Oct 28 23:39 run
> lrwxrwxrwx 1 root root 8 Sep 24 07:43 sbin -> usr/sbin
> drwxr-xr-x 2 root root 4096 Sep 24 07:43 srv
> dr-xr-xr-x 13 nobody nogroup 0 Oct 28 23:39 sys
> drwxrwxrwt 11 root root 4096 Oct 28 23:40 tmp
> drwxr-xr-x 13 root root 4096 Sep 24 07:43 usr
> drwxr-xr-x 12 root root 4096 Sep 24 07:44 var
> root@f2-vm:~# lxc-attach f2 -- ls -al /my-file
> -rw-r--r-- 1 root root 0 Oct 28 23:43 /my-file
> root@f2-vm:~# ls -al /var/lib/lxc/f2/rootfs/my-file
> -rw-r--r-- 1 20000 20000 0 Oct 28 23:43 /var/lib/lxc/f2/rootfs/my-file
>
> I'd like to say thanks to:
> Al for pointing me into the direction to avoid inode alias issues during
> lookup. David for various discussions around this. Christoph for porting
> xfs, providing good reviews and for being involved in the original idea.
> Tycho for helping with this series and on future patches to convert
> filesystems. Alban Crequy and the Kinvolk peeps located just a few
> streets away from me in Berlin for providing use-case discussions and
> writing patches for containerd. Stéphane for his invaluable input on
> many things and level head and enabling me to work on this. Amir for
> explaining and discussing aspects of overlayfs with me. I'd like to
> especially thank Seth Forshee. He provided a lot of good analysis,
> suggestions, and participated in short-notice discussions in both chat
> and video for some nitty-gritty technical details.
>
> This series can be found and pulled from the three usual locations:
> https://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git/log/?h=idmapped_mounts
> https://github.com/brauner/linux/tree/idmapped_mounts
> https://gitlab.com/brauner/linux/-/commits/idmapped_mounts
>
> /* v5 */
> - Adress Christoph's feedback.
> - Use v5.11-rc3 as new base.
> - Add Christoph's xfs port.
>
> /* v4 */
> - Split out several preparatory patches from the initial mount_setattr
> patch as requested by Christoph.
> - Add new tests for file/directory creation in directories with the
> setgid bit set. Specifically, verify that the setgid bit is correctly
> ignored when creating a file with the setgid bit and the parent
> directory's i_gid isn't in_group_p() and the caller isn't
> capable_wrt_inode_uidgid() over the parent directory's inode when
> inode_init_owner() is called.
> Conversely, verify that the setgid bit is set when creating a file
> with the setgid bit and the parent's i_gid is either in_group_p() or
> the caller is capable_wrt_inode_uidgid() over the parent directory's
> inode. In additiona, verify that the setgid bit is always inherited
> when creating directories.
> Test all of this on regular mounts, idmapped mounts, and on idmapped
> mounts in user namespaces.
> - Add new tests to verify that the i_gid of newly created files or
> directories is correctly set to the parent directory's i_gid when the
> parent directory has the setgid bit set.
> - Use "mnt_userns" as the de facto name for a vfsmount's user namespace
> everywhere as suggested by Serge.
> - Reuse existing propagation flags instead of introducing new ones as
> suggested by Christoph. (This is in line with Linus request to not
> introduce too many new flags as evidenced by prior discussions on
> other patchsets such as openat2().)
> - Add first set of Acked-bys from Serge and Reviewed-bys from Christoph.
> - Fix commit messages to reflect the fact that we modify existing
> vfs helpers but do not introduce new ones like we did in the first
> version. Some commit messages still implied we were adding new
> helpers.
> - Reformat all commit messages to adhere to 73 char length limit and
> wrap all lines in commits at 80 chars whenever this doesn't hinder
> legibility.
> - Simplify various codepaths with Christoph's suggestions.
>
> /* v3 */
> - The major change is the port of the test-suite from the
> kernel-internal selftests framework to xfstests as requested by
> Darrick and Christoph. The test-suite for xfstests is patch 38 in this
> series. It has been kept as part of this series even though it belongs
> to xfstests so it's easier to see what is tested and to keep it
> in-sync.
> - Note, the test-suite now has been extended to cover io_uring and
> idmapped mounts. The IORING_REGISTER_PERSONALITY feature allows to
> register the caller's credentials with io_uring and returns an id
> associated with these credentials. This is useful for applications
> that wish to share a ring between separate users/processes. Callers
> can pass in the credential id in the sqe personality field. If set,
> that particular sqe will be issued with these credentials.
> The test-suite now tests that the openat* operations with different
> registered credentials work correctly and safely on regular mounts, on
> regular mounts inside user namespaces, on idmapped mounts, and on
> idmapped mounts inside user namespaces.
>
> /* v2 */
> - The major change is the rework requested by Christoph and others to
> adapt all relevant helpers and inode_operations methods to account for
> idmapped mounts instead of introducing new helpers and methods
> specific to idmapped mounts like we did before. We've also moved the
> overlayfs conversion to handle idmapped mounts into a separate
> patchset that will be sent out separately after the core changes
> landed. The converted filesytems in this series include fat and ext4.
> As per Christoph's request the vfs-wide config option to disable
> idmapped mounts has been removed. Instead the filesystems can decide
> whether or not they want to allow idmap mounts through a config
> option. These config options default to off. Having a config option
> allows us to gain some confidence in the patchset over multiple kernel
> releases.
> - This version introduces a large test-suite to test current vfs
> behavior and idmapped mounts behavior. This test-suite is intended to
> grow over time.
> - While while working on adapting this patchset to the requested
> changes, the runC and containerd crowd was nice enough to adapt
> containerd to this patchset to make use of idmapped mounts in one of
> the most widely used container runtimes:
> https://github.com/containerd/containerd/pull/4734
>
> The solution proposed here has it's origins in multiple discussions
> during Linux Plumbers 2017 during and after the end of the containers
> microconference.
> To the best of my knowledge this involved Aleksa, Stéphane, Eric, David,
> James, and myself.The original idea or a variant thereof has been
> discussed, again to the best of my knowledge, after a Linux conference
> in St. Petersburg in Russia in 2017 between Christoph, Tycho, and
> myself.
> We've taken the time to implement a working version of this solution
> over the last weeks to the best of my abilities. Tycho has signed up
> for this sligthly crazy endeavour as well and he has helped with the
> conversion of the xattr codepaths and will be involved with others in
> converting additional filesystems.
>
> Thanks!
> Christian
>
> Christian Brauner (39):
> namespace: take lock_mount_hash() directly when changing flags
> mount: make {lock,unlock}_mount_hash() static
> namespace: only take read lock in do_reconfigure_mnt()
> fs: split out functions to hold writers
> fs: add attr_flags_to_mnt_flags helper
> fs: add mount_setattr()
> tests: add mount_setattr() selftests
> fs: add id translation helpers
> mount: attach mappings to mounts
> capability: handle idmapped mounts
> namei: make permission helpers idmapped mount aware
> inode: make init and permission helpers idmapped mount aware
> attr: handle idmapped mounts
> acl: handle idmapped mounts
> fs: add file_user_ns() helper
> commoncap: handle idmapped mounts
> stat: handle idmapped mounts
> namei: handle idmapped mounts in may_*() helpers
> namei: introduce struct renamedata
> namei: prepare for idmapped mounts
> open: handle idmapped mounts in do_truncate()
> open: handle idmapped mounts
> af_unix: handle idmapped mounts
> utimes: handle idmapped mounts
> fcntl: handle idmapped mounts
> notify: handle idmapped mounts
> init: handle idmapped mounts
> ioctl: handle idmapped mounts
> would_dump: handle idmapped mounts
> exec: handle idmapped mounts
> fs: make helpers idmap mount aware
> apparmor: handle idmapped mounts
> ima: handle idmapped mounts
> fat: handle idmapped mounts
> ext4: support idmapped mounts
> ecryptfs: do not mount on top of idmapped mounts
> overlayfs: do not mount on top of idmapped mounts
> fs: introduce MOUNT_ATTR_IDMAP
> tests: extend mount_setattr tests
>
> Christoph Hellwig (1):
> xfs: support idmapped mounts
>
> Tycho Andersen (1):
> xattr: handle idmapped mounts
>
> Documentation/filesystems/locking.rst | 6 +-
> Documentation/filesystems/porting.rst | 2 +
> Documentation/filesystems/vfs.rst | 19 +-
> arch/alpha/kernel/syscalls/syscall.tbl | 1 +
> arch/arm/tools/syscall.tbl | 1 +
> arch/arm64/include/asm/unistd32.h | 2 +
> arch/ia64/kernel/syscalls/syscall.tbl | 1 +
> arch/m68k/kernel/syscalls/syscall.tbl | 1 +
> arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
> arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
> arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
> arch/mips/kernel/syscalls/syscall_o32.tbl | 1 +
> arch/parisc/kernel/syscalls/syscall.tbl | 1 +
> arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
> arch/powerpc/platforms/cell/spufs/inode.c | 5 +-
> arch/s390/kernel/syscalls/syscall.tbl | 1 +
> arch/sh/kernel/syscalls/syscall.tbl | 1 +
> arch/sparc/kernel/syscalls/syscall.tbl | 1 +
> arch/x86/entry/syscalls/syscall_32.tbl | 1 +
> arch/x86/entry/syscalls/syscall_64.tbl | 1 +
> arch/xtensa/kernel/syscalls/syscall.tbl | 1 +
> drivers/android/binderfs.c | 6 +-
> drivers/base/devtmpfs.c | 12 +-
> fs/9p/acl.c | 8 +-
> fs/9p/v9fs.h | 3 +-
> fs/9p/v9fs_vfs.h | 2 +-
> fs/9p/vfs_inode.c | 36 +-
> fs/9p/vfs_inode_dotl.c | 39 +-
> fs/9p/xattr.c | 1 +
> fs/adfs/adfs.h | 3 +-
> fs/adfs/inode.c | 5 +-
> fs/affs/affs.h | 10 +-
> fs/affs/inode.c | 7 +-
> fs/affs/namei.c | 15 +-
> fs/afs/dir.c | 34 +-
> fs/afs/inode.c | 9 +-
> fs/afs/internal.h | 7 +-
> fs/afs/security.c | 2 +-
> fs/afs/xattr.c | 2 +
> fs/attr.c | 124 +-
> fs/autofs/root.c | 13 +-
> fs/bad_inode.c | 36 +-
> fs/bfs/dir.c | 12 +-
> fs/btrfs/acl.c | 5 +-
> fs/btrfs/ctree.h | 3 +-
> fs/btrfs/inode.c | 45 +-
> fs/btrfs/ioctl.c | 25 +-
> fs/btrfs/tests/btrfs-tests.c | 2 +-
> fs/btrfs/xattr.c | 2 +
> fs/cachefiles/interface.c | 4 +-
> fs/cachefiles/namei.c | 19 +-
> fs/cachefiles/xattr.c | 16 +-
> fs/ceph/acl.c | 5 +-
> fs/ceph/dir.c | 23 +-
> fs/ceph/inode.c | 17 +-
> fs/ceph/super.h | 12 +-
> fs/ceph/xattr.c | 1 +
> fs/cifs/cifsfs.c | 4 +-
> fs/cifs/cifsfs.h | 21 +-
> fs/cifs/dir.c | 8 +-
> fs/cifs/inode.c | 26 +-
> fs/cifs/link.c | 3 +-
> fs/cifs/xattr.c | 1 +
> fs/coda/coda_linux.h | 6 +-
> fs/coda/dir.c | 17 +-
> fs/coda/inode.c | 9 +-
> fs/coda/pioctl.c | 6 +-
> fs/configfs/configfs_internal.h | 7 +-
> fs/configfs/dir.c | 3 +-
> fs/configfs/inode.c | 5 +-
> fs/configfs/symlink.c | 5 +-
> fs/coredump.c | 14 +-
> fs/crypto/policy.c | 2 +-
> fs/debugfs/inode.c | 9 +-
> fs/ecryptfs/crypto.c | 4 +-
> fs/ecryptfs/inode.c | 80 +-
> fs/ecryptfs/main.c | 6 +
> fs/ecryptfs/mmap.c | 4 +-
> fs/efivarfs/file.c | 2 +-
> fs/efivarfs/inode.c | 4 +-
> fs/erofs/inode.c | 7 +-
> fs/erofs/internal.h | 5 +-
> fs/exec.c | 12 +-
> fs/exfat/exfat_fs.h | 8 +-
> fs/exfat/file.c | 14 +-
> fs/exfat/namei.c | 14 +-
> fs/ext2/acl.c | 5 +-
> fs/ext2/acl.h | 3 +-
> fs/ext2/ext2.h | 5 +-
> fs/ext2/ialloc.c | 2 +-
> fs/ext2/inode.c | 15 +-
> fs/ext2/ioctl.c | 6 +-
> fs/ext2/namei.c | 22 +-
> fs/ext2/xattr_security.c | 1 +
> fs/ext2/xattr_trusted.c | 1 +
> fs/ext2/xattr_user.c | 1 +
> fs/ext4/acl.c | 5 +-
> fs/ext4/acl.h | 3 +-
> fs/ext4/ext4.h | 21 +-
> fs/ext4/ialloc.c | 7 +-
> fs/ext4/inode.c | 21 +-
> fs/ext4/ioctl.c | 19 +-
> fs/ext4/namei.c | 49 +-
> fs/ext4/super.c | 2 +-
> fs/ext4/xattr_hurd.c | 1 +
> fs/ext4/xattr_security.c | 1 +
> fs/ext4/xattr_trusted.c | 1 +
> fs/ext4/xattr_user.c | 1 +
> fs/f2fs/acl.c | 5 +-
> fs/f2fs/acl.h | 3 +-
> fs/f2fs/f2fs.h | 7 +-
> fs/f2fs/file.c | 35 +-
> fs/f2fs/namei.c | 23 +-
> fs/f2fs/xattr.c | 4 +-
> fs/fat/fat.h | 6 +-
> fs/fat/file.c | 24 +-
> fs/fat/namei_msdos.c | 12 +-
> fs/fat/namei_vfat.c | 15 +-
> fs/fcntl.c | 3 +-
> fs/fuse/acl.c | 3 +-
> fs/fuse/dir.c | 45 +-
> fs/fuse/fuse_i.h | 4 +-
> fs/fuse/xattr.c | 2 +
> fs/gfs2/acl.c | 5 +-
> fs/gfs2/acl.h | 3 +-
> fs/gfs2/file.c | 4 +-
> fs/gfs2/inode.c | 59 +-
> fs/gfs2/inode.h | 3 +-
> fs/gfs2/xattr.c | 1 +
> fs/hfs/attr.c | 1 +
> fs/hfs/dir.c | 13 +-
> fs/hfs/hfs_fs.h | 2 +-
> fs/hfs/inode.c | 7 +-
> fs/hfsplus/dir.c | 25 +-
> fs/hfsplus/hfsplus_fs.h | 5 +-
> fs/hfsplus/inode.c | 16 +-
> fs/hfsplus/ioctl.c | 2 +-
> fs/hfsplus/xattr.c | 1 +
> fs/hfsplus/xattr_security.c | 1 +
> fs/hfsplus/xattr_trusted.c | 1 +
> fs/hfsplus/xattr_user.c | 1 +
> fs/hostfs/hostfs_kern.c | 29 +-
> fs/hpfs/hpfs_fn.h | 2 +-
> fs/hpfs/inode.c | 7 +-
> fs/hpfs/namei.c | 20 +-
> fs/hugetlbfs/inode.c | 31 +-
> fs/init.c | 27 +-
> fs/inode.c | 50 +-
> fs/internal.h | 2 +-
> fs/jffs2/acl.c | 5 +-
> fs/jffs2/acl.h | 3 +-
> fs/jffs2/dir.c | 32 +-
> fs/jffs2/fs.c | 7 +-
> fs/jffs2/os-linux.h | 2 +-
> fs/jffs2/security.c | 1 +
> fs/jffs2/xattr_trusted.c | 1 +
> fs/jffs2/xattr_user.c | 1 +
> fs/jfs/acl.c | 5 +-
> fs/jfs/file.c | 9 +-
> fs/jfs/ioctl.c | 2 +-
> fs/jfs/jfs_acl.h | 3 +-
> fs/jfs/jfs_inode.c | 2 +-
> fs/jfs/jfs_inode.h | 2 +-
> fs/jfs/namei.c | 21 +-
> fs/jfs/xattr.c | 2 +
> fs/kernfs/dir.c | 7 +-
> fs/kernfs/inode.c | 19 +-
> fs/kernfs/kernfs-internal.h | 9 +-
> fs/libfs.c | 28 +-
> fs/minix/bitmap.c | 2 +-
> fs/minix/file.c | 7 +-
> fs/minix/inode.c | 6 +-
> fs/minix/minix.h | 3 +-
> fs/minix/namei.c | 24 +-
> fs/mount.h | 10 -
> fs/namei.c | 513 ++++--
> fs/namespace.c | 484 +++++-
> fs/nfs/dir.c | 25 +-
> fs/nfs/inode.c | 9 +-
> fs/nfs/internal.h | 10 +-
> fs/nfs/namespace.c | 14 +-
> fs/nfs/nfs3_fs.h | 3 +-
> fs/nfs/nfs3acl.c | 3 +-
> fs/nfs/nfs4proc.c | 3 +
> fs/nfsd/nfs2acl.c | 4 +-
> fs/nfsd/nfs3acl.c | 4 +-
> fs/nfsd/nfs4acl.c | 4 +-
> fs/nfsd/nfs4recover.c | 6 +-
> fs/nfsd/nfsfh.c | 2 +-
> fs/nfsd/nfsproc.c | 2 +-
> fs/nfsd/vfs.c | 47 +-
> fs/nilfs2/inode.c | 13 +-
> fs/nilfs2/ioctl.c | 2 +-
> fs/nilfs2/namei.c | 19 +-
> fs/nilfs2/nilfs.h | 4 +-
> fs/notify/fanotify/fanotify_user.c | 2 +-
> fs/notify/inotify/inotify_user.c | 3 +-
> fs/ntfs/inode.c | 6 +-
> fs/ntfs/inode.h | 3 +-
> fs/ocfs2/acl.c | 5 +-
> fs/ocfs2/acl.h | 3 +-
> fs/ocfs2/dlmfs/dlmfs.c | 17 +-
> fs/ocfs2/file.c | 17 +-
> fs/ocfs2/file.h | 11 +-
> fs/ocfs2/ioctl.c | 2 +-
> fs/ocfs2/namei.c | 21 +-
> fs/ocfs2/refcounttree.c | 4 +-
> fs/ocfs2/xattr.c | 3 +
> fs/omfs/dir.c | 13 +-
> fs/omfs/file.c | 7 +-
> fs/omfs/inode.c | 2 +-
> fs/open.c | 50 +-
> fs/orangefs/acl.c | 5 +-
> fs/orangefs/inode.c | 20 +-
> fs/orangefs/namei.c | 12 +-
> fs/orangefs/orangefs-kernel.h | 13 +-
> fs/orangefs/xattr.c | 1 +
> fs/overlayfs/copy_up.c | 20 +-
> fs/overlayfs/dir.c | 31 +-
> fs/overlayfs/file.c | 6 +-
> fs/overlayfs/inode.c | 26 +-
> fs/overlayfs/overlayfs.h | 44 +-
> fs/overlayfs/super.c | 19 +-
> fs/overlayfs/util.c | 4 +-
> fs/posix_acl.c | 101 +-
> fs/proc/base.c | 28 +-
> fs/proc/fd.c | 5 +-
> fs/proc/fd.h | 3 +-
> fs/proc/generic.c | 12 +-
> fs/proc/internal.h | 5 +-
> fs/proc/proc_net.c | 5 +-
> fs/proc/proc_sysctl.c | 15 +-
> fs/proc/root.c | 5 +-
> fs/proc_namespace.c | 3 +
> fs/ramfs/file-nommu.c | 9 +-
> fs/ramfs/inode.c | 18 +-
> fs/reiserfs/acl.h | 3 +-
> fs/reiserfs/inode.c | 7 +-
> fs/reiserfs/ioctl.c | 4 +-
> fs/reiserfs/namei.c | 21 +-
> fs/reiserfs/reiserfs.h | 3 +-
> fs/reiserfs/xattr.c | 12 +-
> fs/reiserfs/xattr.h | 3 +-
> fs/reiserfs/xattr_acl.c | 7 +-
> fs/reiserfs/xattr_security.c | 3 +-
> fs/reiserfs/xattr_trusted.c | 3 +-
> fs/reiserfs/xattr_user.c | 3 +-
> fs/remap_range.c | 7 +-
> fs/stat.c | 26 +-
> fs/sysv/file.c | 7 +-
> fs/sysv/ialloc.c | 2 +-
> fs/sysv/itree.c | 6 +-
> fs/sysv/namei.c | 21 +-
> fs/sysv/sysv.h | 3 +-
> fs/tracefs/inode.c | 4 +-
> fs/ubifs/dir.c | 30 +-
> fs/ubifs/file.c | 5 +-
> fs/ubifs/ioctl.c | 2 +-
> fs/ubifs/ubifs.h | 5 +-
> fs/ubifs/xattr.c | 1 +
> fs/udf/file.c | 9 +-
> fs/udf/ialloc.c | 2 +-
> fs/udf/namei.c | 24 +-
> fs/udf/symlink.c | 7 +-
> fs/ufs/ialloc.c | 2 +-
> fs/ufs/inode.c | 7 +-
> fs/ufs/namei.c | 19 +-
> fs/ufs/ufs.h | 3 +-
> fs/utimes.c | 4 +-
> fs/vboxsf/dir.c | 12 +-
> fs/vboxsf/utils.c | 9 +-
> fs/vboxsf/vfsmod.h | 8 +-
> fs/verity/enable.c | 2 +-
> fs/xattr.c | 136 +-
> fs/xfs/xfs_acl.c | 5 +-
> fs/xfs/xfs_acl.h | 3 +-
> fs/xfs/xfs_file.c | 4 +-
> fs/xfs/xfs_inode.c | 26 +-
> fs/xfs/xfs_inode.h | 16 +-
> fs/xfs/xfs_ioctl.c | 23 +-
> fs/xfs/xfs_iops.c | 98 +-
> fs/xfs/xfs_iops.h | 3 +-
> fs/xfs/xfs_qm.c | 3 +-
> fs/xfs/xfs_super.c | 2 +-
> fs/xfs/xfs_symlink.c | 5 +-
> fs/xfs/xfs_symlink.h | 5 +-
> fs/xfs/xfs_xattr.c | 3 +-
> fs/zonefs/super.c | 9 +-
> include/linux/capability.h | 15 +-
> include/linux/fs.h | 158 +-
> include/linux/ima.h | 17 +-
> include/linux/lsm_hook_defs.h | 15 +-
> include/linux/lsm_hooks.h | 1 +
> include/linux/mount.h | 7 +
> include/linux/nfs_fs.h | 7 +-
> include/linux/posix_acl.h | 15 +-
> include/linux/posix_acl_xattr.h | 12 +-
> include/linux/security.h | 46 +-
> include/linux/syscalls.h | 4 +
> include/linux/xattr.h | 30 +-
> include/uapi/asm-generic/unistd.h | 4 +-
> include/uapi/linux/mount.h | 17 +
> ipc/mqueue.c | 8 +-
> kernel/auditsc.c | 5 +-
> kernel/bpf/inode.c | 13 +-
> kernel/capability.c | 14 +-
> kernel/cgroup/cgroup.c | 2 +-
> kernel/sys.c | 2 +-
> mm/madvise.c | 4 +-
> mm/memcontrol.c | 2 +-
> mm/mincore.c | 4 +-
> mm/shmem.c | 48 +-
> net/socket.c | 6 +-
> net/unix/af_unix.c | 4 +-
> security/apparmor/apparmorfs.c | 3 +-
> security/apparmor/domain.c | 13 +-
> security/apparmor/file.c | 5 +-
> security/apparmor/lsm.c | 12 +-
> security/commoncap.c | 109 +-
> security/integrity/evm/evm_crypto.c | 11 +-
> security/integrity/evm/evm_main.c | 4 +-
> security/integrity/evm/evm_secfs.c | 2 +-
> security/integrity/ima/ima.h | 19 +-
> security/integrity/ima/ima_api.c | 10 +-
> security/integrity/ima/ima_appraise.c | 22 +-
> security/integrity/ima/ima_asymmetric_keys.c | 2 +-
> security/integrity/ima/ima_main.c | 31 +-
> security/integrity/ima/ima_policy.c | 19 +-
> security/integrity/ima/ima_queue_keys.c | 2 +-
> security/security.c | 25 +-
> security/selinux/hooks.c | 22 +-
> security/smack/smack_lsm.c | 18 +-
> tools/include/uapi/asm-generic/unistd.h | 4 +-
> tools/testing/selftests/Makefile | 1 +
> .../selftests/mount_setattr/.gitignore | 1 +
> .../testing/selftests/mount_setattr/Makefile | 7 +
> tools/testing/selftests/mount_setattr/config | 1 +
> .../mount_setattr/mount_setattr_test.c | 1424 +++++++++++++++++
> 338 files changed, 4718 insertions(+), 1731 deletions(-)
> create mode 100644 tools/testing/selftests/mount_setattr/.gitignore
> create mode 100644 tools/testing/selftests/mount_setattr/Makefile
> create mode 100644 tools/testing/selftests/mount_setattr/config
> create mode 100644 tools/testing/selftests/mount_setattr/mount_setattr_test.c
>
>
> base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837
> --
> 2.30.0
>