Received-SPF: pass (google.com: domain of selinux-refpolicy-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: How is policy.31 created from modules under /usr/share/selinux
To:     Ashish Mishra <ashishm@mvista.com>
Cc:     Richard Haines <richard_c_haines@btinternet.com>,
        Steve Lawrence <slawrence@owlcyberdefense.com>,
        selinux-refpolicy@vger.kernel.org, Paul Moore <paul@paul-moore.com>
References: <CAP2OjcjCFYiyMfqa=X__X6g0U0143U5Fd-xGaKJgGNabFUpr7w@mail.gmail.com>
 <CAP2OjciTWXRsYWw9VtOJGUOGj9B35HMXBHF94O6Qc=csg5=Spw@mail.gmail.com>
 <e82841a8b652f4b4b697ba1e417fdac56f443adb.camel@btinternet.com>
 <CAP2OjchJjMo8zMVvHk-_esu-53E0=367yV8cuZtwQwubi7+q=Q@mail.gmail.com>
 <0b58a502b5036e8b92b274068fbea53ca915992e.camel@btinternet.com>
 <CAP2Ojcg7DgQsEHJP3TZj=Q9NjZjqb3ugw+D2UYC4qmqt-PcZWw@mail.gmail.com>
 <2806a33b-87ad-61b1-9143-5a24d770a180@ieee.org>
 <CAP2OjcgtcoUmBQZJSzz2DYQ-g23=RrSXT-uefCROUi3y_tU=tg@mail.gmail.com>
 <1b218c6ab1380164cd6c1c774fa4cd3db6d8eb8c.camel@btinternet.com>
 <CAP2OjciFL+zWnyU8VVp1qbD+1mguR8bB9+XPNSR2gbt6avi93g@mail.gmail.com>
 <a926d6a67a7c4013983c716c8a797b9194e2f81a.camel@btinternet.com>
 <217b4754-6f3b-cf71-b0be-440f8517312a@owlcyberdefense.com>
 <cb30c0ce026bbad58666570dd92e172c4ae95955.camel@btinternet.com>
 <950fdabd-07a4-0446-3a3d-4928a14e5962@ieee.org>
 <CAP2OjcjQFgjM_scEgPmu3wka8M=HGWaWQ0Wyb96GkVRwg+zOjA@mail.gmail.com>
From:   Chris PeBenito <pebenito@ieee.org>
Message-ID: <33c70a8e-09be-d779-33ec-a07cbf22440f@ieee.org>
Date:   Mon, 14 Dec 2020 10:16:36 -0500
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.5.0
MIME-Version: 1.0
In-Reply-To: <CAP2OjcjQFgjM_scEgPmu3wka8M=HGWaWQ0Wyb96GkVRwg+zOjA@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 12/13/20 12:06 PM, Ashish Mishra wrote:
> Hi Chris / Richard / Steve ,
> 
> I tried the suggested approach w.r.t Monolithic & also the patch suggested .
> It seems it's creating policy.31 under DESTDIR directories .
> 
> a) Is there anything I can check specifically and share observations ?

I don't understand what you're asking.


> b) Any link where we have this thread available for future reference.
>      I wanted to know if we have any archive which can be accessed like
> other community
>      Something like https://lists.yoctoproject.org/g/poky/topics

The mail list archive is here: https://lore.kernel.org/selinux-refpolicy/


> On Thu, Dec 10, 2020 at 3:32 AM Chris PeBenito <pebenito@ieee.org> wrote:
>>
>> On 12/9/20 11:13 AM, Richard Haines wrote:
>>> On Wed, 2020-12-09 at 10:07 -0500, Steve Lawrence wrote:
>>>>
>>>> On 12/9/20 9:37 AM, Richard Haines wrote:
>>>>> On Wed, 2020-12-09 at 19:42 +0530, Ashish Mishra wrote:
>>>>>> Hi Richard ,
>>>>>>
>>>>>> Will check with the monolithic policy to check the behavior of
>>>>>> the
>>>>>> semodule as you suggested.
>>>>>>
>>>>>> Is there any similar approach / workaround for modular one?
>>>>>
>>>>> I've only had a quick look at code and I could see two ways to fix:
>>>>> 1) Modify the Rules.modular part of the make file to move or copy
>>>>> the
>>>>> policy and file contexts set of files over to $DESTDIR.
>>>>> 2) Modify semodule/semanage to handle $DESTDIR. I think this would
>>>>> be
>>>>> more difficult to fix as lots go on here.
>>>>>
>>>>
>>>> semodule does accept the -p option to change the root, so we could
>>>> feed
>>>> DESTDIR into that. For example, a minimally tested patch:
>>>>
>>>> diff --git a/Rules.modular b/Rules.modular
>>>> index d6224e95..64d953dc 100644
>>>> --- a/Rules.modular
>>>> +++ b/Rules.modular
>>>> @@ -55,8 +55,8 @@ load: $(instpkg) $(appfiles)
>>>>    # make sure two directories exist since they are not
>>>>    # created by semanage
>>>>           @echo "Loading configured modules."
>>>> -       @$(INSTALL) -d -m 0755 $(policypath) $(dir $(fcpath))
>>>> -       $(verbose) $(SEMODULE) -s $(NAME) -i $(modpkgdir)/$(notdir
>>>> $(base_pkg)) $(foreach mod,$(mod_pkgs),-i $(modpkgdir)/$(mod))
>>>> +       @$(INSTALL) -d -m 0755 $(policypath) $(dir $(fcpath))
>>>> $(DESTDIR)/var/lib/selinux
>>>> +       $(verbose) $(SEMODULE) -p $(DESTDIR)/ -s $(NAME) -i
>>>> $(modpkgdir)/$(notdir $(base_pkg)) $(foreach mod,$(mod_pkgs),-i
>>>> $(modpkgdir)/$(mod))
>>>>
>>>>    ########################################
>>>>    #
>>>>
>>>>
>>>> Note that we need to create $(DESTDIR)/var/lib/selinux since semanage
>>>> expects that to already exist.
>>>>
>>>> Though, I would suggest that maybe the "install" target should run
>>>> the
>>>> above semodule command with the --noreload option to install all
>>>> files
>>>> and build the policy binary but not actually load it into the kernel.
>>>> Then make load just becomes something like
>>>>
>>>>     semodule -p $(DESTDIR)/ --reload
>>>>
>>>> Makes a clear distinction between installing everything that's needed
>>>> vs actually loading the policy into the kernel. Happy to create a
>>>> patch
>>>> if that approach makes sense.
>>>
>>> Thanks Steve, that worked for me, however I guess Chris needs to
>>> comment as the $(DESTDIR)/var/lib/selinux needs to be generated and
>>> maybe a clarification comment in the README. Also need comment
>>> regarding the use of --reload/--noreload.
>>
>> To my knowledge, the history is that semodule was only intended to run on the
>> target system.  If you wanted to precreate a policy you could
>> semodule_link+semodule_expand like what is leveraged in the validate target.
>>
>> I'd take a patch that changes the Makefile behavior but would like some real
>> testing first.
>>
>> --
>> Chris PeBenito


-- 
Chris PeBenito