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| author | Christian Brauner <brauner@kernel.org> | 2022-08-29 15:38:43 +0300 |
|---|---|---|
| committer | Christian Brauner (Microsoft) <brauner@kernel.org> | 2022-08-31 17:37:58 +0300 |
| commit | 52edb4080eb9606536c34d5d642ccd9d35ad5d08 (patch) | |
| tree | deb0a8a618fa6d40ff89201f5e223b43e5186d85 /fs/xattr.c | |
| parent | 6b70fe0601adb1396ad0b85cdf05d217500b49e7 (diff) | |
| download | linux-52edb4080eb9606536c34d5d642ccd9d35ad5d08.tar.xz | |
acl: move idmapping handling into posix_acl_xattr_set()
The uapi POSIX ACL struct passed through the value argument during
setxattr() contains {g,u}id values encoded via ACL_{GROUP,USER} entries
that should actually be stored in the form of k{g,u}id_t (See [1] for a
long explanation of the issue.).
In 0c5fd887d2bb ("acl: move idmapped mount fixup into vfs_{g,s}etxattr()")
we took the mount's idmapping into account in order to let overlayfs
handle POSIX ACLs on idmapped layers correctly. The fixup is currently
performed directly in vfs_setxattr() which piles on top of the earlier
hackiness by handling the mount's idmapping and stuff the vfs{g,u}id_t
values into the uapi struct as well. While that is all correct and works
fine it's just ugly.
Now that we have introduced vfs_make_posix_acl() earlier move handling
idmapped mounts out of vfs_setxattr() and into the POSIX ACL handler
where it belongs.
Note that we also need to call vfs_make_posix_acl() for EVM which
interpretes POSIX ACLs during security_inode_setxattr(). Leave them a
longer comment for future reference.
All filesystems that support idmapped mounts via FS_ALLOW_IDMAP use the
standard POSIX ACL xattr handlers and are covered by this change. This
includes overlayfs which simply calls vfs_{g,s}etxattr().
The following filesystems use custom POSIX ACL xattr handlers: 9p, cifs,
ecryptfs, and ntfs3 (and overlayfs but we've covered that in the paragraph
above) and none of them support idmapped mounts yet.
Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org/ [1]
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Seth Forshee (DigitalOcean) <sforshee@kernel.org>
Diffstat (limited to 'fs/xattr.c')
| -rw-r--r-- | fs/xattr.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/fs/xattr.c b/fs/xattr.c index a1f4998bc6be..3ac68ec0c023 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -305,9 +305,6 @@ vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, size = error; } - if (size && is_posix_acl_xattr(name)) - posix_acl_setxattr_idmapped_mnt(mnt_userns, inode, value, size); - retry_deleg: inode_lock(inode); error = __vfs_setxattr_locked(mnt_userns, dentry, name, value, size, |