On Mon, Sep 26, 2022 at 11:24 AM Christian Brauner <brauner@xxxxxxxxxx> wrote: > > In previous patches we implemented get and set inode operations for all > non-stacking filesystems that support posix acls but didn't yet > implement get and/or set acl inode operations. This specifically > affected cifs and 9p. > > Now we can build a posix acl api based solely on get and set inode > operations. We add a new vfs_remove_acl() api that can be used to set > posix acls. This finally removes all type unsafety and type conversion > issues explained in detail in [1] that we aim to get rid of. > > After we finished building the vfs api we can switch stacking > filesystems to rely on the new posix api and then finally switch the > xattr system calls themselves to rely on the posix acl api. > > Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@xxxxxxxxxx [1] > Signed-off-by: Christian Brauner (Microsoft) <brauner@xxxxxxxxxx> > --- > > Notes: > /* v2 */ > unchanged > > fs/posix_acl.c | 65 +++++++++++++++++++++++++++++++++++++++ > include/linux/posix_acl.h | 8 +++++ > 2 files changed, 73 insertions(+) ... > diff --git a/fs/posix_acl.c b/fs/posix_acl.c > index 18873be583a9..40038851bfe1 100644 > --- a/fs/posix_acl.c > +++ b/fs/posix_acl.c > @@ -1484,3 +1484,68 @@ struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, > return acl; > } > EXPORT_SYMBOL(vfs_get_acl); > + > +/** > + * vfs_remove_acl - remove posix acls > + * @mnt_userns: user namespace of the mount > + * @dentry: the dentry based on which to retrieve the posix acls > + * @acl_name: the name of the posix acl > + * > + * This function removes posix acls. > + * > + * Return: On success 0, on error negative errno. > + */ > +int vfs_remove_acl(struct user_namespace *mnt_userns, struct dentry *dentry, > + const char *acl_name) > +{ > + int acl_type; > + int error; > + struct inode *inode = d_inode(dentry); > + struct inode *delegated_inode = NULL; > + > + acl_type = posix_acl_type(acl_name); > + if (acl_type < 0) > + return -EINVAL; > + > +retry_deleg: > + inode_lock(inode); > + > + /* > + * We only care about restrictions the inode struct itself places upon > + * us otherwise POSIX ACLs aren't subject to any VFS restrictions. > + */ > + error = xattr_permission(mnt_userns, inode, acl_name, MAY_WRITE); > + if (error) > + goto out_inode_unlock; > + > + error = security_inode_removexattr(mnt_userns, dentry, acl_name); > + if (error) > + goto out_inode_unlock; Similar to my comments in patch 16/30 for vfs_get_acl(), I would suggest a dedicated ACL remove hook here. Yes, it's still a little bit silly, but if we are going to make one dedicated hook, we might as well do them all. > + error = try_break_deleg(inode, &delegated_inode); > + if (error) > + goto out_inode_unlock; > + > + if (inode->i_opflags & IOP_XATTR) > + error = set_posix_acl(mnt_userns, dentry, acl_type, NULL); > + else if (unlikely(is_bad_inode(inode))) > + error = -EIO; > + else > + error = -EOPNOTSUPP; > + if (!error) { > + fsnotify_xattr(dentry); > + evm_inode_post_removexattr(dentry, acl_name); > + } > + > +out_inode_unlock: > + inode_unlock(inode); > + > + if (delegated_inode) { > + error = break_deleg_wait(&delegated_inode); > + if (!error) > + goto retry_deleg; > + } > + > + return error; > +} > +EXPORT_SYMBOL(vfs_remove_acl); -- paul-moore.com
