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

Serge E. Hallyn
2015-02-03T16:04:08Z

Quoting Mimi Zohar (zohar@linux.vnet.ibm.com):
> On Mon, 2015-02-02 at 18:08 +0000, Serge Hallyn 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.
>
> We're working on resolving the CPIO issue.

Awesome, thanks for that :)

> tar currently supports
> xattrs.

yes, I guess what i was thinking of was a (recent) bug to do with one
of the longer term support older systems. Problem is people want to
run new releases in containers on older systems :)

Anyway when I said "over the years", the first was I believe in 2009/2010,
the last was in 2013 (at that LSS, when Ted mentioned it); so yeah things have
gotten better with respect to this.

But AFAIK we don't yet have any good ideas for tackling the second issue below.

> At this point, how many non-xattr filesystems are there really?
>
> Mimi
>
> > 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.
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>
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