Commit Graph

23 Commits

Author SHA1 Message Date
Jeff Layton
5aa8fd9cea
fs: add a new SB_I_NOUMASK flag
SB_POSIXACL must be set when a filesystem supports POSIX ACLs, but NFSv4
also sets this flag to prevent the VFS from applying the umask on
newly-created files. NFSv4 doesn't support POSIX ACLs however, which
causes confusion when other subsystems try to test for them.

Add a new SB_I_NOUMASK flag that allows filesystems to opt-in to umask
stripping without advertising support for POSIX ACLs. Set the new flag
on NFSv4 instead of SB_POSIXACL.

Also, move mode_strip_umask to namei.h and convert init_mknod and
init_mkdir to use it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230911-acl-fix-v3-1-b25315333f6c@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-10-19 11:02:47 +02:00
Christian Brauner
4609e1f18e
fs: port ->permission() to pass mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:28 +01:00
Christian Brauner
abf08576af
fs: port vfs_*() helpers to struct mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-18 17:51:45 +01:00
Christian Brauner
b816dd5dde
init: handle idmapped mounts
Enable the init helpers to handle idmapped mounts by passing down 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/20210121131959.646623-21-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>
2021-01-24 14:27:19 +01:00
Christian Brauner
6521f89170
namei: prepare for idmapped mounts
The various vfs_*() helpers are called by filesystems or by the vfs
itself to perform core operations such as create, link, mkdir, mknod, rename,
rmdir, tmpfile and unlink. Enable them to handle idmapped mounts. If the
inode is accessed through an idmapped mount map it into the
mount's user namespace and pass it down. Afterwards the checks and
operations 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.

Link: https://lore.kernel.org/r/20210121131959.646623-15-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>
2021-01-24 14:27:18 +01:00
Christian Brauner
ba73d98745
namei: handle idmapped mounts in may_*() helpers
The may_follow_link(), may_linkat(), may_lookup(), may_open(),
may_o_create(), may_create_in_sticky(), may_delete(), and may_create()
helpers determine whether the caller is privileged enough to perform the
associated operations. Let them handle idmapped mounts by mapping the
inode or fsids according to the mount's user namespace. Afterwards the
checks are identical to non-idmapped inodes. The patch takes care to
retrieve the mount's user namespace right before performing permission
checks and passing it down into the fileystem so the user namespace
can't change in between by someone idmapping a mount that is currently
not idmapped. 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/20210121131959.646623-13-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>
2021-01-24 14:27:17 +01:00
Christian Brauner
02f92b3868
fs: add file and path permissions helpers
Add two simple helpers to check permissions on a file and path
respectively and convert over some callers. It simplifies quite a few
codepaths and also reduces the churn in later patches quite a bit.
Christoph also correctly points out that this makes codepaths (e.g.
ioctls) way easier to follow that would otherwise have to do more
complex argument passing than necessary.

Link: https://lore.kernel.org/r/20210121131959.646623-4-christian.brauner@ubuntu.com
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:16 +01:00
Christoph Hellwig
f073531070 init: add an init_dup helper
Add a simple helper to grab a reference to a file and install it at
the next available fd, and switch the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-08-04 21:02:38 -04:00
Christoph Hellwig
235e57935b init: add an init_utimes helper
Add a simple helper to set timestamps with a kernel space file name and
switch the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:54 +02:00
Christoph Hellwig
716308a533 init: add an init_stat helper
Add a simple helper to stat with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:54 +02:00
Christoph Hellwig
5fee64fcde init: add an init_mknod helper
Add a simple helper to mknod with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_mknod.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:54 +02:00
Christoph Hellwig
83ff98c3e9 init: add an init_mkdir helper
Add a simple helper to mkdir with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_mkdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
cd3acb6a79 init: add an init_symlink helper
Add a simple helper to symlink with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_symlink.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
812931d693 init: add an init_link helper
Add a simple helper to link with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_link.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
eb9d7d390e init: add an init_eaccess helper
Add a simple helper to check if a file exists based on kernel space file
name and switch the early init code over to it.  Note that this
theoretically changes behavior as it always is based on the effective
permissions.  But during early init that doesn't make a difference.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
1097742efc init: add an init_chmod helper
Add a simple helper to chmod with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
b873498f99 init: add an init_chown helper
Add a simple helper to chown with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
4b7ca5014c init: add an init_chroot helper
Add a simple helper to chroot with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_chroot.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
db63f1e315 init: add an init_chdir helper
Add a simple helper to chdir with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_chdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
20cce026c3 init: add an init_rmdir helper
Add a simple helper to rmdir with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_rmdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
8fb9f73e5a init: add an init_unlink helper
Add a simple helper to unlink with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_unlink.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
09267defa3 init: add an init_umount helper
Like ksys_umount, but takes a kernel pointer for the destination path.
Switch over the umount in the init code, which just happen to work due to
the implicit set_fs(KERNEL_DS) during early init right now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:51 +02:00
Christoph Hellwig
c60166f042 init: add an init_mount helper
Like do_mount, but takes a kernel pointer for the destination path.
Switch over the mounts in the init code and devtmpfs to it, which
just happen to work due to the implicit set_fs(KERNEL_DS) during early
init right now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:51 +02:00