Re: [PATCH v6 0/1] ns: introduce binfmt_misc namespace

Laurent Vivier [off-list ref] writes:

On 01/11/2018 04:51, Jann Horn wrote:

quoted

On Thu, Nov 1, 2018 at 3:59 AM James Bottomley
[off-list ref] wrote:

quoted

On Tue, 2018-10-16 at 11:52 +0200, Laurent Vivier wrote:

quoted

Hi,

Any comment on this last version?

Any chance to be merged?

I've got a use case for this:  I went to one of the Graphene talks in
Edinburgh and it struck me that we seem to keep reinventing the type of
sandboxing that qemu-user already does.  However if you want to do an
x86 on x86 sandbox, you can't currently use the binfmt_misc mechanism
because that has you running *every* binary on the system emulated.
Doing it per user namespace fixes this problem and allows us to at
least cut down on all the pointless duplication.

Waaaaaait. What? qemu-user does not do "sandboxing". qemu-user makes
your code slower and *LESS* secure. As far as I know, qemu-user is
only intended for purposes like development and testing.

I think the idea here is not to run qemu, but to use an interpreter
(something like gVisor) into a container to control the binaries
execution inside the container without using this interpreter on the
host itself (container and host shares the same binfmt_misc
magic/mask).

Please remind me of this patchset after the merge window is over, and if
there are no issues I will take it via my user namespace branch.

Last I looked I had a concern that some of the permission check issues
were being papered over by using override cred instead of fixing the
deaper code.  Sometimes they are necessary but seeing work-arounds
instead of fixes for problems tends to be a maintenance issue, possibly
with security consequences.  Best is if the everyone agrees on how all
of the interfaces work so their are no surprises.

Eric