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From:   "Eric W. Biederman" <ebiederm@xmission.com>
To:     Kees Cook <keescook@chromium.org>
Cc:     Robert =?utf-8?B?xZp3acSZY2tp?= <robert@swiecki.net>,
        Andy Lutomirski <luto@amacapital.net>,
        Will Drewry <wad@chromium.org>, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
References: <20220210025321.787113-1-keescook@chromium.org>
Date:   Thu, 10 Feb 2022 12:17:50 -0600
In-Reply-To: <20220210025321.787113-1-keescook@chromium.org> (Kees Cook's
        message of "Wed, 9 Feb 2022 18:53:18 -0800")
Message-ID: <871r0a8u29.fsf@email.froward.int.ebiederm.org>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)
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Content-Type: text/plain
Subject: Re: [PATCH 0/3] signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE
Precedence: bulk

Kees Cook <keescook@chromium.org> writes:

> Hi,
>
> This fixes the signal refactoring to actually kill unkillable processes
> when receiving a fatal SIGSYS from seccomp. Thanks to Robert for the
> report and Eric for the fix! I've also tweaked seccomp internal a bit to
> fail more safely. This was a partial seccomp bypass, in the sense that
> SECCOMP_RET_KILL_* didn't kill the process, but it didn't bypass other
> aspects of the filters. (i.e. the syscall was still blocked, etc.)

Any luck on figuring out how to suppress the extra event?
>
> I'll be sending this to Linus after a bit more testing...
>
> Thanks,
>
> -Kees
>
> Kees Cook (3):
>   signal: HANDLER_EXIT should clear SIGNAL_UNKILLABLE
>   seccomp: Invalidate seccomp mode to catch death failures
>   samples/seccomp: Adjust sample to also provide kill option
>
>  kernel/seccomp.c          | 10 ++++++++++
>  kernel/signal.c           |  5 +++--
>  samples/seccomp/dropper.c |  9 +++++++--
>  3 files changed, 20 insertions(+), 4 deletions(-)

Eric