attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking.

attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

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inode: make init and permission helpers idmapped mount aware

The inode_owner_or_capable() helper determines whether the caller is the
owner of the inode or is capable with respect to that inode. All

inode: make init and permission helpers idmapped mount aware

The inode_owner_or_capable() helper determines whether the caller is the
owner of the inode or is capable with respect to that inode. Allow it to
handle idmapped mounts. If the inode is accessed through an idmapped
mount it according to the mount's user namespace. Afterwards the checks
are identical to non-idmapped mounts. If the initial user namespace is
passed nothing changes so non-idmapped mounts will see identical
behavior as before.

Similarly, allow the inode_init_owner() helper to handle idmapped
mounts. It initializes a new inode on idmapped mounts by mapping the
fsuid and fsgid of the caller from the mount's user namespace. If the
initial user namespace is passed nothing changes so non-idmapped mounts
will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-7-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

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namei: make permission helpers idmapped mount aware

The two helpers inode_permission() and generic_permission() are used by
the vfs to perform basic permission checking by verifying that the
caller

namei: make permission helpers idmapped mount aware

The two helpers inode_permission() and generic_permission() are used by
the vfs to perform basic permission checking by verifying that the
caller is privileged over an inode. In order to handle idmapped mounts
we extend the two helpers with an additional user namespace argument.
On idmapped mounts the two helpers will make sure to map the inode
according to the mount's user namespace and then peform identical
permission checks to inode_permission() and generic_permission(). If the
initial user namespace is passed nothing changes so non-idmapped mounts
will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-6-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

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capability: handle idmapped mounts

In order to determine whether a caller holds privilege over a given
inode the capability framework exposes the two helpers
privileged_wrt_inode_uidgid() and capabl

capability: handle idmapped mounts

In order to determine whether a caller holds privilege over a given
inode the capability framework exposes the two helpers
privileged_wrt_inode_uidgid() and capable_wrt_inode_uidgid(). The former
verifies that the inode has a mapping in the caller's user namespace and
the latter additionally verifies that the caller has the requested
capability in their current user namespace.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped inodes. If the initial user namespace is passed all
operations are a nop so non-idmapped mounts will not see a change in
behavior.

Link: https://lore.kernel.org/r/20210121131959.646623-5-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

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Merge branch 'next' into for-linus

Prepare input updates for 5.8 merge window.

Merge branch 'for-5.8' into for-linus

Merge tag 'v5.6' into next

Sync up with mainline to get device tree and other changes.

Merge branch 'for-5.7/appleir' into for-linus

- small code cleanups in hid-appleir from Lucas Tanure

Merge branch 'x86/kdump' into locking/kcsan, to resolve conflicts

Conflicts:
arch/x86/purgatory/Makefile

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge drm/drm-next into drm-intel-next-queued

Some DSI and VBT pending patches from Hans will apply
cleanly and with less ugly conflicts if they are rebuilt
on top of other patches that recently lan

Merge drm/drm-next into drm-intel-next-queued

Some DSI and VBT pending patches from Hans will apply
cleanly and with less ugly conflicts if they are rebuilt
on top of other patches that recently landed on drm-next.

Reference: https://patchwork.freedesktop.org/series/70952/
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com

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Merge tag 'v5.6-rc3' into sched/core, to pick up fixes and dependent patches

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge v5.6-rc2 into drm-misc-next

Lyude needs some patches in 5.6-rc2 and we didn't bring drm-misc-next
forward yet, so it looks like a good occasion.

Signed-off-by: Maxime Ripard <maxime@cerno.tec

Merge v5.6-rc2 into drm-misc-next

Lyude needs some patches in 5.6-rc2 and we didn't bring drm-misc-next
forward yet, so it looks like a good occasion.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>

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Merge v5.6-rc1 into drm-misc-fixes

We're based on v5.6, need v5.6-rc1 at least. :)

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

Merge branch 'imm.timestamp' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs timestamp updates from Al Viro:
"More 64bit timestamp work"

* 'imm.timestamp' of git://git.kernel.or

Merge branch 'imm.timestamp' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs timestamp updates from Al Viro:
"More 64bit timestamp work"

* 'imm.timestamp' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
kernfs: don't bother with timestamp truncation
fs: Do not overload update_time
fs: Delete timespec64_trunc()
fs: ubifs: Eliminate timespec64_trunc() usage
fs: ceph: Delete timespec64_trunc() usage
fs: cifs: Delete usage of timespec64_trunc
fs: fat: Eliminate timespec64_trunc() usage
utimes: Clamp the timestamps in notify_change()

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utimes: Clamp the timestamps in notify_change()

Push clamping timestamps into notify_change(), so in-kernel
callers like nfsd and overlayfs will get similar timestamp
set behavior as utimes.

AV: ge

utimes: Clamp the timestamps in notify_change()

Push clamping timestamps into notify_change(), so in-kernel
callers like nfsd and overlayfs will get similar timestamp
set behavior as utimes.

AV: get rid of clamping in ->setattr() instances; we don't need
to bother with that there, with notify_change() doing normalization
in all cases now (it already did for implicit case, since current_time()
clamps).

Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 42e729b9ddbb ("utimes: Clamp the timestamps before update")
Cc: stable@vger.kernel.org # v5.4
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

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Merge branch 'next' into for-linus

Prepare input updates for 5.5 merge window.

Merge tag 'v5.4-rc8' into WIP.x86/mm, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'linus' into x86/hyperv

Pick up upstream fixes to avoid conflicts.

Merge tag 'v5.4-rc5' into next

Sync up with mainline.

Merge tag 'v5.4-rc3' into spi-5.4

Linux 5.4-rc3

Merge drm/drm-next into drm-intel-next-queued

Backmerging to pull in HDR DP code:

https://lists.freedesktop.org/archives/dri-devel/2019-September/236453.html

Signed-off-by: Joonas Lahtinen <joonas

Merge drm/drm-next into drm-intel-next-queued

Backmerging to pull in HDR DP code:

https://lists.freedesktop.org/archives/dri-devel/2019-September/236453.html

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

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Merge tag 'fix-missing-panels' into fixes

Merge drm/drm-next into drm-misc-next

We haven't done any backmerge for a while due to the merge window, and it
starts to become an issue for komeda. Let's bring 5.4-rc1 in.

Signed-off-by: Maxime R

Merge drm/drm-next into drm-misc-next

We haven't done any backmerge for a while due to the merge window, and it
starts to become an issue for komeda. Let's bring 5.4-rc1 in.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

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Merge drm/drm-fixes into drm-misc-fixes

We haven't backmerged for a while, let's start the -rc period by pulling
rc1.

Signed-off-by: Maxime Ripard <mripard@kernel.org>

Merge tag 'y2038-vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground

Pull y2038 vfs updates from Arnd Bergmann:
"Add inode timestamp clamping.

This series from Deepa Dinamani a

Merge tag 'y2038-vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground

Pull y2038 vfs updates from Arnd Bergmann:
"Add inode timestamp clamping.

This series from Deepa Dinamani adds a per-superblock minimum/maximum
timestamp limit for a file system, and clamps timestamps as they are
written, to avoid random behavior from integer overflow as well as
having different time stamps on disk vs in memory.

At mount time, a warning is now printed for any file system that can
represent current timestamps but not future timestamps more than 30
years into the future, similar to the arbitrary 30 year limit that was
added to settimeofday().

This was picked as a compromise to warn users to migrate to other file
systems (e.g. ext4 instead of ext3) when they need the file system to
survive beyond 2038 (or similar limits in other file systems), but not
get in the way of normal usage"

* tag 'y2038-vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground:
ext4: Reduce ext4 timestamp warnings
isofs: Initialize filesystem timestamp ranges
pstore: fs superblock limits
fs: omfs: Initialize filesystem timestamp ranges
fs: hpfs: Initialize filesystem timestamp ranges
fs: ceph: Initialize filesystem timestamp ranges
fs: sysv: Initialize filesystem timestamp ranges
fs: affs: Initialize filesystem timestamp ranges
fs: fat: Initialize filesystem timestamp ranges
fs: cifs: Initialize filesystem timestamp ranges
fs: nfs: Initialize filesystem timestamp ranges
ext4: Initialize timestamps limits
9p: Fill min and max timestamps in sb
fs: Fill in max and min timestamps in superblock
utimes: Clamp the timestamps before update
mount: Add mount warning for impending timestamp expiry
timestamp_truncate: Replace users of timespec64_trunc
vfs: Add timestamp_truncate() api
vfs: Add file timestamp range support

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