Thread (11 messages) 11 messages, 5 authors, 2017-05-04

[kernel-hardening] Re: [PATCH v4 1/2] tiocsti-restrict : Add owner user namespace to tty_struct

From: serge@hallyn.com (Serge E. Hallyn)
Date: 2017-05-04 04:42:12
Also in: lkml

On Wed, May 03, 2017 at 01:19:41PM -0700, Kees Cook wrote:
On Wed, May 3, 2017 at 1:02 PM, Matt Brown [off-list ref] wrote:
quoted
On 05/03/2017 03:45 PM, Greg KH wrote:
quoted
On Wed, May 03, 2017 at 12:32:07PM -0700, Kees Cook wrote:
quoted
On Mon, Apr 24, 2017 at 6:57 AM, Serge E. Hallyn [off-list ref]
wrote:
quoted
Quoting Matt Brown (matt at nmatt.com):
quoted
This patch adds struct user_namespace *owner_user_ns to the tty_struct.
Then it is set to current_user_ns() in the alloc_tty_struct function.

This is done to facilitate capability checks against the original user
namespace that allocated the tty.

E.g. ns_capable(tty->owner_user_ns,CAP_SYS_ADMIN)

This combined with the use of user namespace's will allow hardening
protections to be built to mitigate container escapes that utilize TTY
ioctls such as TIOCSTI.

See: https://bugzilla.redhat.com/show_bug.cgi?id=1411256

Signed-off-by: Matt Brown <redacted>

Acked-by: Serge Hallyn <serge@hallyn.com>

This Ack didn't end up in the v5, but I think it stands, yes?

Greg, is the v5 okay to pull for you or would a v6 with Acks/Reviews
included be preferred?

v6 would be great, and we are dropping patch 2 from the series, right?
I was expecting this to be resent.  I'll start looking at new patches
like this after 4.12-rc1 is out.
I will create a v6 with the Acks/Reviews. I'd like to keep patch 2 in
since that got acked by at least Serge. (Kees also? or just patch 1?)
Sorry, I meant that patch 2's ack from serge got dropped accidentally.
i.e. he Acked v4, but it wasn't in v5.

Serge, just to double-check, does your Ack stand?
Yes.

thanks,
-serge
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