[v2,02/30] 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]
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
---

Notes:
    /* v2 */
    Christoph Hellwig <hch@lst.de>:
    - Split orangefs into a preparatory patch.

 fs/bad_inode.c                |  2 +-
 fs/btrfs/acl.c                |  3 ++-
 fs/btrfs/ctree.h              |  2 +-
 fs/btrfs/inode.c              |  2 +-
 fs/ceph/acl.c                 |  3 ++-
 fs/ceph/inode.c               |  2 +-
 fs/ceph/super.h               |  2 +-
 fs/ext2/acl.c                 |  3 ++-
 fs/ext2/acl.h                 |  2 +-
 fs/ext2/inode.c               |  2 +-
 fs/ext4/acl.c                 |  3 ++-
 fs/ext4/acl.h                 |  2 +-
 fs/ext4/inode.c               |  2 +-
 fs/f2fs/acl.c                 |  4 +++-
 fs/f2fs/acl.h                 |  2 +-
 fs/f2fs/file.c                |  2 +-
 fs/fuse/acl.c                 |  3 ++-
 fs/fuse/fuse_i.h              |  2 +-
 fs/gfs2/acl.c                 |  3 ++-
 fs/gfs2/acl.h                 |  2 +-
 fs/gfs2/inode.c               |  2 +-
 fs/jffs2/acl.c                |  3 ++-
 fs/jffs2/acl.h                |  2 +-
 fs/jffs2/fs.c                 |  2 +-
 fs/jfs/acl.c                  |  3 ++-
 fs/jfs/file.c                 |  2 +-
 fs/jfs/jfs_acl.h              |  2 +-
 fs/ksmbd/smb2pdu.c            |  4 ++--
 fs/ksmbd/smbacl.c             |  4 ++--
 fs/ksmbd/vfs.c                | 15 ++++++++-------
 fs/ksmbd/vfs.h                |  4 ++--
 fs/nfs/nfs3_fs.h              |  2 +-
 fs/nfs/nfs3acl.c              |  3 ++-
 fs/nfsd/nfs2acl.c             |  4 ++--
 fs/nfsd/nfs3acl.c             |  4 ++--
 fs/nfsd/vfs.c                 |  4 ++--
 fs/ntfs3/file.c               |  2 +-
 fs/ntfs3/ntfs_fs.h            |  4 ++--
 fs/ntfs3/xattr.c              |  9 +++++----
 fs/ocfs2/acl.c                |  3 ++-
 fs/ocfs2/acl.h                |  2 +-
 fs/orangefs/acl.c             |  5 +++--
 fs/orangefs/inode.c           |  7 ++++---
 fs/orangefs/orangefs-kernel.h |  4 ++--
 fs/posix_acl.c                | 18 +++++++++++-------
 fs/reiserfs/acl.h             |  6 +++---
 fs/reiserfs/inode.c           |  2 +-
 fs/reiserfs/xattr_acl.c       |  9 ++++++---
 fs/xfs/xfs_acl.c              |  3 ++-
 fs/xfs/xfs_acl.h              |  2 +-
 fs/xfs/xfs_iops.c             | 10 ++++++----
 include/linux/fs.h            |  2 +-
 include/linux/posix_acl.h     | 12 ++++++------
 mm/shmem.c                    |  2 +-
 54 files changed, 118 insertions(+), 92 deletions(-)

Message ID	20220926140827.142806-3-brauner@kernel.org (mailing list archive)
State	Superseded
Delegated to:	Paul Moore
Headers	show Return-Path: <linux-security-module-owner@kernel.org> From: Christian Brauner <brauner@kernel.org> To: linux-fsdevel@vger.kernel.org Cc: Christian Brauner <brauner@kernel.org>, Seth Forshee <sforshee@kernel.org>, Christoph Hellwig <hch@lst.de>, Al Viro <viro@zeniv.linux.org.uk>, linux-security-module@vger.kernel.org Subject: [PATCH v2 02/30] fs: pass dentry to set acl method Date: Mon, 26 Sep 2022 16:07:59 +0200 Message-Id: <20220926140827.142806-3-brauner@kernel.org> In-Reply-To: <20220926140827.142806-1-brauner@kernel.org> References: <20220926140827.142806-1-brauner@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	acl: add vfs posix acl api \| expand [v2,00/30] acl: add vfs posix acl api [v2,01/30] orangefs: rework posix acl handling when creating new filesystem objects [v2,02/30] fs: pass dentry to set acl method [v2,03/30] fs: rename current get acl method [v2,04/30] fs: add new get acl method [v2,05/30] cifs: implement get acl method [v2,06/30] cifs: implement set acl method [v2,07/30] 9p: implement get acl method [v2,08/30] 9p: implement set acl method [v2,09/30] acl: add vfs_set_acl() [v2,10/30] security: add set acl hook [v2,11/30] selinux: implement set acl hook [v2,12/30] smack: implement set acl hook [v2,13/30] evm: implement set acl hook [v2,14/30] acl: use set acl hook [v2,15/30] evm: add post set acl hook [v2,16/30] acl: add vfs_get_acl() [v2,17/30] acl: add vfs_remove_acl() [v2,18/30] evm: simplify evm_xattr_acl_change() [v2,19/30] ksmbd: use vfs_remove_acl() [v2,20/30] ecryptfs: implement get acl method [v2,21/30] ecryptfs: implement set acl method [v2,22/30] ovl: implement get acl method [v2,23/30] ovl: implement set acl method [v2,24/30] ovl: use posix acl api [v2,25/30] xattr: use posix acl api [v2,26/30] ecryptfs: use stub posix acl handlers [v2,27/30] ovl: use stub posix acl handlers [v2,28/30] cifs: use stub posix acl handlers [v2,29/30] 9p: use stub posix acl handlers [v2,30/30] acl: remove a slew of now unused helpers

[v2,02/30] fs: pass dentry to set acl method

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Patch