Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 24 Nov 2020 16:45:46 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Mark Wielaard <mark@klomp.org>
Cc:     Florian Weimer <fweimer@redhat.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        linux-api@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, dev@opencontainers.org,
        corbet@lwn.net, Carlos O'Donell <carlos@redhat.com>
Subject: Re: [PATCH] syscalls: Document OCI seccomp filter interactions &
 workaround
Message-ID: <20201124164546.GA14094@infradead.org>
References: <87lfer2c0b.fsf@oldenburg2.str.redhat.com>
 <20201124122639.x4zqtxwlpnvw7ycx@wittgenstein>
 <878saq3ofx.fsf@oldenburg2.str.redhat.com>
 <dcffcbacbc75086582ea3f073c9e6a981a6dd27f.camel@klomp.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <dcffcbacbc75086582ea3f073c9e6a981a6dd27f.camel@klomp.org>
Precedence: bulk

On Tue, Nov 24, 2020 at 03:08:05PM +0100, Mark Wielaard wrote:
> For valgrind the issue is statx which we try to use before falling back
> to stat64, fstatat or stat (depending on architecture, not all define
> all of these). The problem with these fallbacks is that under some
> containers (libseccomp versions) they might return EPERM instead of
> ENOSYS. This causes really obscure errors that are really hard to
> diagnose.

So find a way to detect these completely broken container run times
and refuse to run under them at all.  After all they've decided to
deliberately break the syscall ABI.  (and yes, we gave the the rope
to do that with seccomp :().