Linux-Fsdevel Archive on lore.kernel.org
 help / color / Atom feed
From: Paul Moore <paul@paul-moore.com>
To: Richard Guy Briggs <rgb@redhat.com>
Cc: Steve Grubb <sgrubb@redhat.com>,
	linux-audit@redhat.com, nhorman@tuxdriver.com,
	linux-api@vger.kernel.org, containers@lists.linux-foundation.org,
	LKML <linux-kernel@vger.kernel.org>,
	dhowells@redhat.com, netfilter-devel@vger.kernel.org,
	ebiederm@xmission.com, simo@redhat.com, netdev@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, Eric Paris <eparis@parisplace.org>,
	mpatel@redhat.com, Serge Hallyn <serge@hallyn.com>
Subject: Re: [PATCH ghak90 V8 07/16] audit: add contid support for signalling the audit daemon
Date: Wed, 18 Mar 2020 18:06:00 -0400
Message-ID: <CAHC9VhSdDDP7Ec-w61NhGxZG5ZiekmrBCAg=Y=VJvEZcgQh46g@mail.gmail.com> (raw)
In-Reply-To: <20200318215550.es4stkjwnefrfen2@madcap2.tricolour.ca>

On Wed, Mar 18, 2020 at 5:56 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2020-03-18 17:42, Paul Moore wrote:
> > On Wed, Mar 18, 2020 at 5:27 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > On 2020-03-18 16:56, Paul Moore wrote:
> > > > On Fri, Mar 13, 2020 at 2:59 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > > > On 2020-03-13 12:29, Paul Moore wrote:
> > > > > > On Thu, Mar 12, 2020 at 3:30 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > > > > > On 2020-02-13 16:44, Paul Moore wrote:
> > > > > > > > This is a bit of a thread-hijack, and for that I apologize, but
> > > > > > > > another thought crossed my mind while thinking about this issue
> > > > > > > > further ... Once we support multiple auditd instances, including the
> > > > > > > > necessary record routing and duplication/multiple-sends (the host
> > > > > > > > always sees *everything*), we will likely need to find a way to "trim"
> > > > > > > > the audit container ID (ACID) lists we send in the records.  The
> > > > > > > > auditd instance running on the host/initns will always see everything,
> > > > > > > > so it will want the full container ACID list; however an auditd
> > > > > > > > instance running inside a container really should only see the ACIDs
> > > > > > > > of any child containers.
> > > > > > >
> > > > > > > Agreed.  This should be easy to check and limit, preventing an auditd
> > > > > > > from seeing any contid that is a parent of its own contid.
> > > > > > >
> > > > > > > > For example, imagine a system where the host has containers 1 and 2,
> > > > > > > > each running an auditd instance.  Inside container 1 there are
> > > > > > > > containers A and B.  Inside container 2 there are containers Y and Z.
> > > > > > > > If an audit event is generated in container Z, I would expect the
> > > > > > > > host's auditd to see a ACID list of "1,Z" but container 1's auditd
> > > > > > > > should only see an ACID list of "Z".  The auditd running in container
> > > > > > > > 2 should not see the record at all (that will be relatively
> > > > > > > > straightforward).  Does that make sense?  Do we have the record
> > > > > > > > formats properly designed to handle this without too much problem (I'm
> > > > > > > > not entirely sure we do)?
> > > > > > >
> > > > > > > I completely agree and I believe we have record formats that are able to
> > > > > > > handle this already.
> > > > > >
> > > > > > I'm not convinced we do.  What about the cases where we have a field
> > > > > > with a list of audit container IDs?  How do we handle that?
> > > > >
> > > > > I don't understand the problem.  (I think you crossed your 1/2 vs
> > > > > A/B/Y/Z in your example.) ...
> > > >
> > > > It looks like I did, sorry about that.
> > > >
> > > > > ... Clarifying the example above, if as you
> > > > > suggest an event happens in container Z, the hosts's auditd would report
> > > > >         Z,^2
> > > > > and the auditd in container 2 would report
> > > > >         Z,^2
> > > > > but if there were another auditd running in container Z it would report
> > > > >         Z
> > > > > while the auditd in container 1 or A/B would see nothing.
> > > >
> > > > Yes.  My concern is how do we handle this to minimize duplicating and
> > > > rewriting the records?  It isn't so much about the format, although
> > > > the format is a side effect.
> > >
> > > Are you talking about caching, or about divulging more information than
> > > necessary or even information leaks?  Or even noticing that records that
> > > need to be generated to two audit daemons share the same contid field
> > > values and should be generated at the same time or information shared
> > > between them?  I'd see any of these as optimizations that don't affect
> > > the api.
> >
> > Imagine a record is generated in a container which has more than one
> > auditd in it's ancestry that should receive this record, how do we
> > handle that without completely killing performance?  That's my
> > concern.  If you've already thought up a plan for this - excellent,
> > please share :)
>
> No, I haven't given that much thought other than the correctness and
> security issues of making sure that each audit daemon is sufficiently
> isolated to do its job but not jeopardize another audit domain.  Audit
> already kills performance, according to some...
>
> We currently won't have that problem since there can only be one so far.
> Fixing and optimizing this is part of the next phase of the challenge of
> adding a second audit daemon.
>
> Let's work on correctness and reasonable efficiency for this phase and
> not focus on a problem we don't yet have.  I wouldn't consider this
> incurring technical debt at this point.

I agree, one stage at a time, but the choice we make here is going to
have a significant impact on what we can do later.  We need to get
this as "right" as possible; this isn't something we should dismiss
with a hand-wave as a problem for the next stage.  We don't need an
implementation, but I would like to see a rough design of how we would
address this problem.

> I could see cacheing a contid string from one starting point, but it may
> be more work to search that cached string to truncate it or add to it
> when another audit daemon requests a copy of a similar string.  I
> suppose every full contid string could be generated the first time it is
> used and parts of it used (start/finish) as needed but that
> search/indexing may not be worth it.

I hope we can do better than string manipulations in the kernel.  I'd
much rather defer generating the ACID list (if possible), than
generating a list only to keep copying and editing it as the record is
sent.

-- 
paul moore
www.paul-moore.com

  reply index

Thread overview: 99+ 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 [this message]
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
2020-04-16 20:33                                                           ` Eric W. Biederman
2020-04-16 21:53                                                             ` Paul Moore
2020-04-17 22:23                                                               ` Eric W. Biederman
2020-04-22 17:24                                                                 ` 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
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAHC9VhSdDDP7Ec-w61NhGxZG5ZiekmrBCAg=Y=VJvEZcgQh46g@mail.gmail.com' \
    --to=paul@paul-moore.com \
    --cc=containers@lists.linux-foundation.org \
    --cc=dhowells@redhat.com \
    --cc=ebiederm@xmission.com \
    --cc=eparis@parisplace.org \
    --cc=linux-api@vger.kernel.org \
    --cc=linux-audit@redhat.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mpatel@redhat.com \
    --cc=netdev@vger.kernel.org \
    --cc=netfilter-devel@vger.kernel.org \
    --cc=nhorman@tuxdriver.com \
    --cc=rgb@redhat.com \
    --cc=serge@hallyn.com \
    --cc=sgrubb@redhat.com \
    --cc=simo@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Fsdevel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-fsdevel/0 linux-fsdevel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-fsdevel linux-fsdevel/ https://lore.kernel.org/linux-fsdevel \
		linux-fsdevel@vger.kernel.org
	public-inbox-index linux-fsdevel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-fsdevel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git