On Wed, May 03, 2017 at 12:32:07PM -0700, Kees Cook wrote:

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.

thanks,

greg k-h
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