fs: port ->set_acl() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("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>

fs: pass dentry to set acl method

The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

Since some filesystem rely on the dentry being available to them when
setting posix acls (e.g., 9p and cifs) they cannot rely on set acl inode
operation. But since ->set_acl() is required in order to use the generic
posix acl xattr handlers filesystems that do not implement this inode
operation cannot use the handler and need to implement their own
dedicated posix acl handlers.

Update the ->set_acl() inode method to take a dentry argument. This
allows all filesystems to rely on ->set_acl().

As far as I can tell all codepaths can be switched to rely on the dentry
instead of just the inode. Note that the original motivation for passing
the dentry separate from the inode instead of just the dentry in the
xattr handlers was because of security modules that call
security_d_instantiate(). This hook is called during
d_instantiate_new(), d_add(), __d_instantiate_anon(), and
d_splice_alias() to initialize the inode's security context and possibly
to set security.* xattrs. Since this only affects security.* xattrs this
is completely irrelevant for posix acls.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

vfs: add rcu argument to ->get_acl() callback

Add a rcu argument to the ->get_acl() callback to allow
get_cached_acl_rcu() to call the ->get_acl() method in the next patch.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs: make helpers idmap mount aware

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-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>

Convert jffs2 acl to struct_size

Need to tell the compiler that the acl entries follow the acl header.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

jffs2: use generic posix ACL infrastructure

Also don't bother to set up a .get_acl method for symlinks as we do not
support access control (ACLs or even mode bits) for symlinks in Linux.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

switch posix_acl_create() to umode_t *

so we can pass &inode->i_mode to it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs: take the ACL checks to common code

Replace the ->check_acl method with a ->get_acl method that simply reads an
ACL from disk after having a cache miss. This means we can replace the ACL
checking boilerplate code with a single implementation in namei.c.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fix jffs2 ACLs on big-endian with 16bit mode_t

casting int * to mode_t * is not a good thing - on a *lot* of big-endian
architectures mode_t happens to be smaller than int and there it breaks
quite spectaculary...

Fucked-up-by: commit cfc8dc6f6f69ede939e09c2af06a01adee577285
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

->permission() sanitizing: don't pass flags to ->check_acl()

not used in the instances anymore.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs: provide rcu-walk aware permission i_ops

Signed-off-by: Nick Piggin <npiggin@kernel.dk>

jffs2: constify xattr_handler

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

jffs2/jfs/xfs: switch over to 'check_acl' rather than 'permission()'

This avoids an indirect call in the VFS for each path component lookup.

Well, at least as long as you own the directory in question, and the ACL
check is unnecessary.

Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

switch jffs2 to inode->i_acl

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[PATCH] sanitize ->permission() prototype

* kill nameidata * argument; map the 3 bits in ->flags anybody cares
about to new MAY_... ones and pass with the mask.
* kill redundant gfs2_iop_permission()
* sanitize ecryptfs_permission()
* fix remaining places where ->permission() instances might barf on new
MAY_... found in mask.

The obvious next target in that direction is permission(9)

folded fix for nfs_permission() breakage from Miklos Szeredi <mszeredi@suse.cz>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

[JFFS2] make jffs2_get_acl() static

jffs2_get_acl() can now become static again.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Tidy up fix for ACL/permissions problem.

[In commit 9ed437c50d89eabae763dd422579f73fdebf288d we fixed a problem
with standard permissions on newly-created inodes, when POSIX ACLs are
enabled. This cleans it up...]

The attached patch separate jffs2_init_acl() into two parts.

The one is jffs2_init_acl_pre() called from jffs2_new_inode().
It compute ACL oriented inode->i_mode bits, and allocate in-memory ACL
objects associated with the new inode just before when inode meta
infomation is written to the medium.

The other is jffs2_init_acl_post() called from jffs2_symlink(),
jffs2_mkdir(), jffs2_mknod() and jffs2_do_create().
It actually writes in-memory ACL objects into the medium next to
the success of writing meta-information.

In the current implementation, we have to write a same inode meta
infomation twice when inode->i_mode is updated by the default ACL.
However, we can avoid the behavior by putting an updated i_mode
before it is written at first, as jffs2_init_acl_pre() doing.

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Fix ACL vs. mode handling.

When POSIX ACL support was enabled, we weren't writing correct
legacy modes to the medium on inode creation, or when the ACL was set.
This meant that the permissions would be incorrect after the file system
was remounted.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2] Tidy up licensing/copyright boilerplate.

In particular, remove the bit in the LICENCE file about contacting
Red Hat for alternative arrangements. Their errant IS department broke
that arrangement a long time ago -- the policy of collecting copyright
assignments from contributors came to an end when the plug was pulled on
the servers hosting the project, without notice or reason.

We do still dual-license it for use with eCos, with the GPL+exception
licence approved by the FSF as being GPL-compatible. It's just that nobody
has the right to license it differently.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2][XATTR] Fix memory leak in POSIX-ACL support

jffs2_clear_acl() which releases acl caches allocated by kmalloc()
was defined but it was never called. Thus, we faced to the risk
of memory leaking.

This patch plugs jffs2_clear_acl() into jffs2_do_clear_inode().
It ensures to release acl cache when inode is cleared.

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

[JFFS2][XATTR] remove '__KERNEL__' from acl.h

[9/10] jffs2-xattr-v5.1-09-remove__KERNEL__.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] Unify each file header part with any jffs2 file.

Unify each file header part with any jffs2 file.

[7/10] jffs2-xattr-v5.1-07-unify_file_header.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] remove typedef from posix_acl related definition.

jffs2_acl_header, jffs2_acl_entry and jffs2_acl_entry_short were redefined
with using 'struct' instead of 'typedef' in kernel implementation.

[1/10] jffs2-xattr-v5.1-01-remove_typedef_kernel.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>

[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>