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From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Florian Weimer <fweimer@redhat.com>,
	Josh Max <JMax@mail.greenriver.edu>,
	viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Carlos O'Donell" <carlos@redhat.com>
Subject: Re: [PATCH] binfmt_misc: allow selecting the interpreter based on xattr keywords
Date: Sat, 27 Aug 2016 12:52:30 +0100	[thread overview]
Message-ID: <20160827125230.25b9d3e1@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <1472246778.5189.90.camel@HansenPartnership.com>

On Fri, 26 Aug 2016 17:26:18 -0400
James Bottomley <James.Bottomley@HansenPartnership.com> wrote:

> On Fri, 2016-08-26 at 22:12 +0100, One Thousand Gnomes wrote:
> > > A non-security use case would be to run the binary (without 
> > > modification) with a different ELF interpreter (assuming this 
> > > allows to override binfmt_elf, but self-sandboxing would need that 
> > > as well).  This would make it easier to use older or newer libcs 
> > > for select binaries on the system.  Right now, one has to write 
> > > wrappers for that, and the explicit dynamic linker invocation is 
> > > not completely transparent to the application.  
> > 
> > If it gets in I'll be using it to label CP/M COM files so that they 
> > can be auto-run nicely when crossbuilding stuff in part with the 
> > original tools but a modern build environment 8)
> > 
> > Sandboxing is an obvious use but there are more bizarre ones such as
> > marking a file system image to get auto-run under a virtual machine 
> > or make containers fire up as if they were commands.  
> 
> So I asked previously but didn't get an answer.  If this is useful for
> sandboxing and being in the sandbox depends on the xattr value,
> shouldn't it be in one of the privileged xattr namespaces, not the
> user. one?

IMHO no 

- because it's not giving additional rights, it is taking rights away
  voluntarily
- because as a user I can simply cp the file to get an unsandboxed version

If it was a setuid like bit then yes it would matter.

Alan

      reply	other threads:[~2016-08-27 11:52 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-22  4:01 [PATCH] binfmt_misc: allow selecting the interpreter based on xattr keywords Josh Max
2016-08-25 16:15 ` James Bottomley
2016-08-26  8:00   ` Josh Max
2016-08-26 14:55   ` Florian Weimer
2016-08-26 17:59     ` Carlos O'Donell
2016-08-26 21:38       ` James Bottomley
2016-11-11 10:31       ` Alex Bennée
2016-08-26 21:12     ` One Thousand Gnomes
2016-08-26 21:26       ` James Bottomley
2016-08-27 11:52         ` One Thousand Gnomes [this message]

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