Re: [capabilities] Allow normal inheritance for a configurable set of capabilities

Andy Lutomirski
2015-02-02T20:38:19Z

On Mon, Feb 2, 2015 at 10:08 AM, Serge Hallyn <serge.hallyn@ubuntu.com> wrote:
> Quoting Casey Schaufler (casey@schaufler-ca.com):
>> I'm game to participate in such an effort. The POSIX scheme
>> is workable, but given that it's 20 years old and hasn't
>> developed real traction it's hard to call it successful.
>
> Over the years we've several times discussed possible reasons for this
> and how to help. I personally think it's two things: 1. lack of
> toolchain and fs support. The fact that we cannot to this day enable
> ping using capabilities by default because of cpio, tar and non-xattr
> filesystems is disheartening. 2. It's hard for users and applications
> to know what caps they need. yes the API is a bear to use, but we can
> hide that behind fancier libraries. But using capabilities requires too
> much in-depth knowledge of precisely what caps you might need for
> whatever operations library may now do when you asked for something.

None of this could address the problem here, though: if I hold a
capability and I want to pass that capability to an exec'd helper, I
shouldn't need the fs's help to do this.

--Andy