Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <cover.1593198710.git.rgb@redhat.com> <b6cb5500cfd7e8686ac2a7758103688c2da7f4ce.1593198710.git.rgb@redhat.com>
In-Reply-To: <b6cb5500cfd7e8686ac2a7758103688c2da7f4ce.1593198710.git.rgb@redhat.com>
From:   Paul Moore <paul@paul-moore.com>
Date:   Sun, 5 Jul 2020 11:11:47 -0400
Message-ID: <CAHC9VhRvuu-_+gh9ejr0sFDNR6erV2BAig6qrT9gOEB6GczXvw@mail.gmail.com>
Subject: Re: [PATCH ghak90 V9 13/13] audit: add capcontid to set contid
 outside init_user_ns
To:     Richard Guy Briggs <rgb@redhat.com>
Cc:     containers@lists.linux-foundation.org, linux-api@vger.kernel.org,
        Linux-Audit Mailing List <linux-audit@redhat.com>,
        linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
        sgrubb@redhat.com, Ondrej Mosnacek <omosnace@redhat.com>,
        dhowells@redhat.com, simo@redhat.com,
        Eric Paris <eparis@parisplace.org>,
        Serge Hallyn <serge@hallyn.com>, ebiederm@xmission.com,
        nhorman@tuxdriver.com, Dan Walsh <dwalsh@redhat.com>,
        mpatel@redhat.com
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Sat, Jun 27, 2020 at 9:24 AM Richard Guy Briggs <rgb@redhat.com> wrote:
>
> Provide a mechanism similar to CAP_AUDIT_CONTROL to explicitly give a
> process in a non-init user namespace the capability to set audit
> container identifiers of individual children.
>
> Provide the /proc/$PID/audit_capcontid interface to capcontid.
> Valid values are: 1==enabled, 0==disabled
>
> Writing a "1" to this special file for the target process $PID will
> enable the target process to set audit container identifiers of its
> descendants.
>
> A process must already have CAP_AUDIT_CONTROL in the initial user
> namespace or have had audit_capcontid enabled by a previous use of this
> feature by its parent on this process in order to be able to enable it
> for another process.  The target process must be a descendant of the
> calling process.
>
> Report this action in new message type AUDIT_SET_CAPCONTID 1022 with
> fields opid= capcontid= old-capcontid=
>
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> ---
>  fs/proc/base.c             | 57 +++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/audit.h      | 14 ++++++++++++
>  include/uapi/linux/audit.h |  1 +
>  kernel/audit.c             | 38 ++++++++++++++++++++++++++++++-
>  4 files changed, 108 insertions(+), 2 deletions(-)

This seems very similar to the capable/ns_capable combination I
mentioned in patch 11/13; any reasons why you feel that this might be
a better approach?  My current thinking is that the capable/ns_capable
approach is preferable as it leverages existing kernel mechanisms and
doesn't require us to reinvent the wheel in the audit subsystem.


--
paul moore
www.paul-moore.com