From: Casey Schaufler <casey@schaufler-ca.com>
To: Paul Moore <paul@paul-moore.com>
Cc: Steve Grubb <sgrubb@redhat.com>,
Richard Guy Briggs <rgb@redhat.com>,
"linux-audit@redhat.com" <linux-audit@redhat.com>,
Linux Security Module list
<linux-security-module@vger.kernel.org>,
casey@schaufler-ca.com
Subject: Re: Preferred subj= with multiple LSMs
Date: Tue, 16 Jul 2019 10:58:47 -0700 [thread overview]
Message-ID: <38418eec-d6a0-9cf4-542e-e68bd3ee80bc@schaufler-ca.com> (raw)
In-Reply-To: <CAHC9VhSTwvueKcK2yhckwayh9YGou7gt2Gny36DOTaNkrck+Mg@mail.gmail.com>
On 7/16/2019 10:43 AM, Paul Moore wrote:
> On Tue, Jul 16, 2019 at 1:30 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
>> On 7/16/2019 10:12 AM, Paul Moore wrote:
>>> On Mon, Jul 15, 2019 at 6:56 PM Steve Grubb <sgrubb@redhat.com> wrote:
>>>> On Monday, July 15, 2019 5:28:56 PM EDT Paul Moore wrote:
>>>>> On Mon, Jul 15, 2019 at 3:37 PM Casey Schaufler <casey@schaufler-ca.com>
>>>> wrote:
>>>>>> On 7/15/2019 12:04 PM, Richard Guy Briggs wrote:
>>>>>>> On 2019-07-13 11:08, Steve Grubb wrote:
>>> ...
>>>
>>>>>>> Steve's answer is the obvious one, ideally allocating a seperate range
>>>>>>> to each LSM with each message type having its own well defined format.
>>>>>> It doesn't address the issue of success records, or records
>>>>>> generated outside the security modules.
>>>>> Yes, exactly. The individual LSM will presumably will continue to
>>>>> generate their own audit records as they do today and I would imagine
>>>>> that the subject and object fields could remain as they do today for
>>>>> the LSM specific records.
>>>>>
>>>>> The trick is the other records which are not LSM specific but still
>>>>> want to include subject and/or object information. Unfortunately we
>>>>> are stuck with some tough limitations given the current audit record
>>>>> format and Steve's audit userspace tools;
>>>> Not really. We just need to approach the problem thinking about how to make
>>>> it work based on how things currently work.
>>> I suppose it is all somewhat "subjective" - bad joke fully intended :)
>>> - with respect to what one considers good/bad/limiting. My personal
>>> view is that an ideal solution would allow for multiple independent
>>> subj/obj labels without having to multiplex on a single subj/obj
>>> field. My gut feeling is that this would confuse your tools, yes?
>>>
>>>> For example Casey had a list of possible formats. Like this one:
>>>>
>>>> Option 3:
>>>> lsms=selinux,apparmor subj=x:y:z:s:c subj=a
>>>>
>>>> I'd suggest something almost like that. The first field could be a map to
>>>> decipher the labels. Then we could have a comma separated list of labels.
>>>>
>>>> lsms=selinux,apparmor subj=x:y:z:s:c,a
>>> Some quick comments:
>>>
>>> * My usual reminder that new fields for existing audit records must be
>>> added to the end of the record.
>>>
>>> * If we are going to multiplex the labels on a single field (more on
>>> that below) I might suggest using "subj_lsms" instead of "lsms" so we
>>> leave ourself some wiggle room in the future.
>>>
>>> * Multiplexing on a single "subj" field is going to be difficult
>>> because picking the label delimiter is going to be a pain. For
>>> example, in the example above a comma is used, which at the very least
>>> is a valid part of a SELinux label and I suspect for Smack as well
>>> (I'm not sure about the other LSMs). I suspect the only way to parse
>>> out the component labels would be to have knowledge of the LSMs in
>>> use, as well as the policies loaded at the time the audit record was
>>> generated.
>>>
>>> This may be a faulty assumption, but assuming your tools will fall
>>> over if they see multiple "subj" fields, could we do something like
>>> the following (something between option #2 and #3):
>>>
>>> subj1_lsm=smack subj1=<smack_label> subj2_lsm=selinux
>>> subj2=<selinux_label> ...
>> If it's not a subj= field why use the indirection?
>>
>> subj_smack=<smack_label> subj_selinux=<selinux_label>
>>
>> would be easier.
> Good point, that looks reasonable to me.
Which raises the question of what to do with the subj= :
- omit it
- subj=?
- subj=some-special-message
- subj=label-of-first-lsm
next prev parent reply other threads:[~2019-07-16 17:58 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 16:33 Preferred subj= with multiple LSMs Casey Schaufler
[not found] ` <c46932ec-e38e-ba15-7ceb-70e0fe0ef5dc@schaufler-ca.com>
2019-07-13 15:08 ` Steve Grubb
2019-07-15 19:04 ` Richard Guy Briggs
[not found] ` <1979804.kRvuSoDnao@x2>
[not found] ` <2802ddee-b621-c2eb-9ff3-ea15c4f19d0c@schaufler-ca.com>
[not found] ` <3577098.oGDFHdoSSQ@x2>
2019-07-16 17:16 ` Casey Schaufler
[not found] ` <CAHC9VhSELVZN8feH56zsANqoHu16mPMD04Ww60W=r6tWs+8WnQ@mail.gmail.com>
2019-07-16 17:29 ` Casey Schaufler
2019-07-16 17:43 ` Paul Moore
2019-07-16 17:58 ` Casey Schaufler [this message]
2019-07-16 18:06 ` Steve Grubb
2019-07-16 18:41 ` Casey Schaufler
2019-07-16 21:25 ` Paul Moore
2019-07-16 21:46 ` Steve Grubb
2019-07-16 22:18 ` Casey Schaufler
2019-07-16 23:13 ` Paul Moore
2019-07-16 23:47 ` Casey Schaufler
2019-07-17 12:14 ` Paul Moore
2019-07-17 15:49 ` Casey Schaufler
2019-07-17 16:23 ` Paul Moore
2019-07-17 23:02 ` Casey Schaufler
2019-07-18 13:10 ` Simon McVittie
2019-07-18 16:13 ` Casey Schaufler
2019-07-19 12:15 ` Simon McVittie
2019-07-19 16:29 ` Casey Schaufler
2019-07-19 18:47 ` Simon McVittie
2019-07-19 20:02 ` Dbus and multiple LSMs (was Preferred subj= with multiple LSMs) Casey Schaufler
2019-07-22 11:36 ` Simon McVittie
2019-07-22 16:04 ` Casey Schaufler
2019-07-19 21:21 ` Preferred subj= with multiple LSMs Paul Moore
2019-07-22 20:50 ` James Morris
2019-07-22 22:01 ` Casey Schaufler
2019-07-22 22:30 ` Paul Moore
2019-07-23 0:11 ` Casey Schaufler
2019-07-23 14:06 ` Simon McVittie
2019-07-23 17:32 ` Casey Schaufler
2019-07-23 21:46 ` James Morris
2019-07-16 23:09 ` Paul Moore
2019-07-17 4:36 ` James Morris
2019-07-17 12:23 ` Paul Moore
2019-07-18 15:01 ` William Roberts
2019-07-18 18:48 ` Casey Schaufler
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