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From:   rishi gupta <gupt21@gmail.com>
Date:   Fri, 6 Nov 2020 21:20:50 +0530
Message-ID: <CALUj-gtyVJ9nLYWYbX2Oa9=dcCYqc2H0RkO4HQcJKj2ejAfSYg@mail.gmail.com>
Subject: Re: Selinux policy for x509_ima.der public certificate loaded by
 kernel during boot
To:     Mikhail Novosyolov <m.novosyolov@rosalinux.ru>
Cc:     linux-integrity <linux-integrity@vger.kernel.org>,
        selinux-refpolicy@vger.kernel.org, selinux@vger.kernel.org
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On Fri, Nov 6, 2020 at 8:42 PM Mikhail Novosyolov
<m.novosyolov@rosalinux.ru> wrote:
>
> 06.11.2020 15:22, rishi gupta =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> > I am getting below error as selinux is denying access to the .ima
> > keyring. Looking for guidance for asymmetric public key selinux
> > policy.
> >
> > [  172.014855] integrity: Request for unknown key 'id:87deb3bf' err -13
> I am getting the same error without selinux.
If I make selinux permissive, it works for me. So I know in my case
the problem is selinux.
> >
> > [  172.015035] audit: type=3D1800 audit(1604596570.579:240): pid=3D825
> > uid=3D1021 auid=3D4294967295 ses=3D4294967295
> > subj=3Dsystem_u:system_r:mydaemon_t:s0-s15:c0.c1023 op=3D"appraise_data=
"
> > cause=3D"invalid-signature" comm=3D"mydaemon"
> > name=3D"/usr/lib/libstdc++.so.6.0.25" dev=3D"ubifs" ino=3D14353 res=3D0
> Selinux context is just logged here. It has nothing to do with reasons of=
 ivalid signature. Public key seems to be not loaded.
Basically when we access a file, driver checks if selinux allow access
to it or not. In my case this function is returning -EACCES
https://github.com/torvalds/linux/blob/master/security/keys/permission.c#L8=
8
> >
> > (a) Do I need to set the selinux context of file
> > /etc/keys/x509_ima.der. If yes what it should be.
> > (b) Do I need to set some selinux rule for .ima keyring. If yes how. I
> > tried a lot but could not find any resource.
> Usually IMA policy is loaded before SELinux policy I think
I am using the policy defined in ima_policy driver as of now. My kernel is =
4.14.
> >
> > Regards,
> > Rishi