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From:   Paul Moore <paul@paul-moore.com>
Date:   Tue, 15 Feb 2022 15:02:51 -0500
Message-ID: <CAHC9VhSHxk0MUR1krpmbot6iG-vqH48sRgKOnJQ0LsFTs6Jvqg@mail.gmail.com>
Subject: Re: [PATCH net v3 2/2] security: implement sctp_assoc_established
 hook in selinux
To:     Xin Long <lucien.xin@gmail.com>
Cc:     Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Ondrej Mosnacek <omosnace@redhat.com>,
        netdev <netdev@vger.kernel.org>,
        David Miller <davem@davemloft.net>,
        SElinux list <selinux@vger.kernel.org>,
        Richard Haines <richard_c_haines@btinternet.com>,
        Vlad Yasevich <vyasevich@gmail.com>,
        Neil Horman <nhorman@tuxdriver.com>,
        "open list:SCTP PROTOCOL" <linux-sctp@vger.kernel.org>,
        LSM List <linux-security-module@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Prashanth Prahlad <pprahlad@redhat.com>
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On Mon, Feb 14, 2022 at 11:13 PM Xin Long <lucien.xin@gmail.com> wrote:
> Looks okay to me.
>
> The difference from the old one is that: with
> selinux_sctp_process_new_assoc() called in
> selinux_sctp_assoc_established(), the client sksec->peer_sid is using
> the first asoc's peer_secid, instead of the latest asoc's peer_secid.
> And not sure if it will cause any problems when doing the extra check
> sksec->peer_sid != asoc->peer_secid for the latest asoc and *returns
> err*. But I don't know about selinux, I guess there must be a reason
> from selinux side.

Generally speaking we don't want to change any SELinux socket labels
once it has been created.  While the peer_sid is a bit different,
changing it after userspace has access to the socket could be
problematic.  In the case where the peer_sid differs between the two
we have a permission check which allows policy to control this
behavior which seems like the best option at this point.

> I will ACK on patch 0/2.

Thanks, I'm going to go ahead and merge these two patches into
selinux/next right now.

-- 
paul-moore.com