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From: Paul Moore <paul@paul-moore.com>
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, 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
Subject: Re: [PATCH ghak90 V8 12/16] audit: contid check descendancy and nesting
Date: Wed, 22 Jan 2020 16:29:05 -0500
Message-ID: <CAHC9VhT1+mx_tVzyXD=UBqagqYgAFjZ=X1A6oBiMvjVCn8=V-w@mail.gmail.com> (raw)
In-Reply-To: <cfbb80a08fc770dd0dcf6dac6ff307a80d877c3f.1577736799.git.rgb@redhat.com>

On Tue, Dec 31, 2019 at 2:51 PM Richard Guy Briggs <rgb@redhat.com> wrote:
>
> Require the target task to be a descendant of the container
> orchestrator/engine.
>
> You would only change the audit container ID from one set or inherited
> value to another if you were nesting containers.
>
> If changing the contid, the container orchestrator/engine must be a
> descendant and not same orchestrator as the one that set it so it is not
> possible to change the contid of another orchestrator's container.
>
> Since the task_is_descendant() function is used in YAMA and in audit,
> remove the duplication and pull the function into kernel/core/sched.c
>
> Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> ---
>  include/linux/sched.h    |  3 +++
>  kernel/audit.c           | 44 ++++++++++++++++++++++++++++++++++++--------
>  kernel/sched/core.c      | 33 +++++++++++++++++++++++++++++++++
>  security/yama/yama_lsm.c | 33 ---------------------------------
>  4 files changed, 72 insertions(+), 41 deletions(-)

...

> diff --git a/kernel/audit.c b/kernel/audit.c
> index f7a8d3288ca0..ef8e07524c46 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -2603,22 +2610,43 @@ int audit_set_contid(struct task_struct *task, u64 contid)
>         oldcontid = audit_get_contid(task);
>         read_lock(&tasklist_lock);
>         /* Don't allow the contid to be unset */
> -       if (!audit_contid_valid(contid))
> +       if (!audit_contid_valid(contid)) {
>                 rc = -EINVAL;
> +               goto unlock;
> +       }
>         /* Don't allow the contid to be set to the same value again */
> -       else if (contid == oldcontid) {
> +       if (contid == oldcontid) {
>                 rc = -EADDRINUSE;
> +               goto unlock;
> +       }
>         /* if we don't have caps, reject */
> -       else if (!capable(CAP_AUDIT_CONTROL))
> +       if (!capable(CAP_AUDIT_CONTROL)) {
>                 rc = -EPERM;
> -       /* if task has children or is not single-threaded, deny */
> -       else if (!list_empty(&task->children))
> +               goto unlock;
> +       }
> +       /* if task has children, deny */
> +       if (!list_empty(&task->children)) {
>                 rc = -EBUSY;
> -       else if (!(thread_group_leader(task) && thread_group_empty(task)))
> +               goto unlock;
> +       }
> +       /* if task is not single-threaded, deny */
> +       if (!(thread_group_leader(task) && thread_group_empty(task))) {
>                 rc = -EALREADY;
> -       /* if contid is already set, deny */
> -       else if (audit_contid_set(task))
> +               goto unlock;
> +       }

It seems like the if/else-if conversion above should be part of an
earlier patchset.

> +       /* if task is not descendant, block */
> +       if (task == current) {
> +               rc = -EBADSLT;
> +               goto unlock;
> +       }
> +       if (!task_is_descendant(current, task)) {
> +               rc = -EXDEV;
> +               goto unlock;
> +       }

I understand you are trying to provide a unique error code for each
failure case, but this is getting silly.  Let's group the descendent
checks under the same error code.

> +       /* only allow contid setting again if nesting */
> +       if (audit_contid_set(task) && audit_contid_isowner(task))
>                 rc = -ECHILD;

Should that be "!audit_contid_isowner()"?

--
paul moore
www.paul-moore.com

  reply index

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-31 19:48 [PATCH ghak90 V8 00/16] audit: implement container identifier Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 01/16] audit: collect audit task parameters Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 02/16] audit: add container id Richard Guy Briggs
2020-01-22 21:28   ` Paul Moore
2020-01-30 17:53     ` Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 03/16] audit: read container ID of a process Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 04/16] audit: convert to contid list to check for orch/engine ownership Richard Guy Briggs
2020-01-22 21:28   ` Paul Moore
2020-02-04 22:51     ` Richard Guy Briggs
2020-02-05 22:40       ` Paul Moore
2019-12-31 19:48 ` [PATCH ghak90 V8 05/16] audit: log drop of contid on exit of last task Richard Guy Briggs
2020-01-22 21:28   ` Paul Moore
2020-02-04 23:02     ` Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 06/16] audit: log container info of syscalls Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 07/16] audit: add contid support for signalling the audit daemon Richard Guy Briggs
2020-01-22 21:28   ` Paul Moore
2020-01-23 16:29     ` Richard Guy Briggs
2020-01-23 17:09       ` Paul Moore
2020-01-23 20:04         ` Richard Guy Briggs
2020-01-23 21:35           ` Paul Moore
2020-02-04 23:14             ` Richard Guy Briggs
2020-02-05 22:50               ` Paul Moore
2020-02-12 22:38                 ` Steve Grubb
2020-02-13  0:09                   ` Paul Moore
2020-02-13 21:44                     ` Paul Moore
2020-03-12 19:30                       ` Richard Guy Briggs
2020-03-13 16:29                         ` Paul Moore
2020-03-13 18:59                           ` Richard Guy Briggs
2020-03-18 20:56                             ` Paul Moore
2020-03-18 21:26                               ` Richard Guy Briggs
2020-03-18 21:42                                 ` Paul Moore
2020-03-18 21:55                                   ` Richard Guy Briggs
2020-03-18 22:06                                     ` Paul Moore
2020-03-19 22:02                                       ` Richard Guy Briggs
2020-03-24  0:16                                         ` Paul Moore
2020-03-24 21:01                                           ` Richard Guy Briggs
2020-03-29  3:11                                             ` Paul Moore
2020-03-30 13:47                                               ` Richard Guy Briggs
2020-03-30 14:26                                                 ` Paul Moore
2020-03-30 16:21                                                   ` Richard Guy Briggs
2020-03-30 17:34                                                     ` Paul Moore
2020-03-30 17:49                                                       ` Richard Guy Briggs
2020-03-30 19:55                                                         ` Paul Moore
2020-03-12 20:27                     ` Richard Guy Briggs
2020-03-13 16:42                       ` Paul Moore
2020-03-13 16:45                         ` Steve Grubb
2020-03-13 16:49                           ` Paul Moore
2020-03-13 19:23                         ` Richard Guy Briggs
2020-03-18 21:01                           ` Paul Moore
2020-03-18 21:41                             ` Richard Guy Briggs
2020-03-18 21:47                               ` Paul Moore
2020-03-19 21:47                                 ` Richard Guy Briggs
2020-03-20 21:56                                   ` Paul Moore
2020-03-25 12:29                                     ` Richard Guy Briggs
2020-03-29  3:17                                       ` Paul Moore
2020-03-30 15:23                                         ` Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 08/16] audit: add support for non-syscall auxiliary records Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 09/16] audit: add containerid support for user records Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 10/16] audit: add containerid filtering Richard Guy Briggs
2019-12-31 19:48 ` [PATCH ghak90 V8 11/16] audit: add support for containerid to network namespaces Richard Guy Briggs
2020-01-22 21:28   ` Paul Moore
2020-02-04 23:42     ` Richard Guy Briggs
2020-02-05 22:51       ` Paul Moore
2019-12-31 19:48 ` [PATCH ghak90 V8 12/16] audit: contid check descendancy and nesting Richard Guy Briggs
2020-01-22 21:29   ` Paul Moore [this message]
2020-01-23 21:02     ` Richard Guy Briggs
2020-01-23 21:47       ` Paul Moore
2019-12-31 19:48 ` [PATCH ghak90 V8 13/16] audit: track container nesting Richard Guy Briggs
2020-01-22 21:29   ` Paul Moore
2020-01-30 19:27     ` Richard Guy Briggs
2020-02-05 23:05       ` Paul Moore
2020-02-05 23:50         ` Richard Guy Briggs
2020-02-13 21:49           ` Paul Moore
2020-03-12 20:51             ` Richard Guy Briggs
2020-03-13 16:47               ` Paul Moore
2020-03-14 22:42                 ` Richard Guy Briggs
2020-03-17 18:28                   ` Richard Guy Briggs
2020-03-18 21:08                   ` Paul Moore
2020-01-31 14:50     ` Steve Grubb
2020-02-04 13:19       ` Richard Guy Briggs
2020-02-04 15:47         ` Steve Grubb
2020-02-04 15:52           ` Paul Moore
2020-02-04 18:12             ` Steve Grubb
2020-02-05 22:57               ` Paul Moore
2019-12-31 19:48 ` [PATCH ghak90 V8 14/16] audit: check contid depth and add limit config param Richard Guy Briggs
2020-01-22 21:29   ` Paul Moore
2019-12-31 19:48 ` [PATCH ghak90 V8 15/16] audit: check contid count per netns and add config param limit Richard Guy Briggs
2020-01-22 21:29   ` Paul Moore
2019-12-31 19:48 ` [PATCH ghak90 V8 16/16] audit: add capcontid to set contid outside init_user_ns Richard Guy Briggs
2020-01-22 21:29   ` Paul Moore
2020-02-05  0:39     ` Richard Guy Briggs
2020-02-05 22:56       ` Paul Moore
2020-02-06 12:51         ` Richard Guy Briggs
2020-02-13 21:58           ` Paul Moore
2020-03-12 21:58             ` Richard Guy Briggs

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