Re: implement-file-posix-capabilities.patch

James Morris
2007-06-24T16:19:04Z

On Sun, 24 Jun 2007, Serge E. Hallyn wrote:

> > 2) Allocate capability bit-31 for CAP_SETFCAP, and use it to gate
> > whether the user can set this xattr on a file or not. CAP_SYS_ADMIN is
> > way too overloaded and this functionality is special.
>
> The functionality is special, but someone with CAP_SYS_ADMIN can always
> unload the capability module and create the security.capability xattr
> using the dummy module.
>
> If we do add this cap, do we want to make it apply to all security.*
> xattrs?

The underlying issue here is the notion of security mechanisms which are
built as loadable modules. It's not useful for any in-tree users, and
introduces several unnecessary problems which then need to be addressed.

A better approach would be to make LSM a statically linked interface.

This would also allow us to unexport the LSM symbols and reduce the API
abuse by third-party modules.

- James
--
James Morris
<jmorris@namei.org>