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From:   ebiederm@xmission.com (Eric W. Biederman)
To:     Kees Cook <keescook@chromium.org>
Cc:     Andrea Righi <andrea.righi@canonical.com>,
        Shuah Khan <shuah@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Andy Lutomirski <luto@amacapital.net>,
        Will Drewry <wad@chromium.org>,
        linux-kselftest@vger.kernel.org, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
References: <YXrN+Hnl9pSOsWlA@arighi-desktop> <202110280955.B18CB67@keescook>
        <878rydm56l.fsf@disp2133> <202110281136.5CE65399A7@keescook>
        <8735okls76.fsf@disp2133> <202110290755.451B036CE9@keescook>
Date:   Tue, 02 Nov 2021 13:22:19 -0500
In-Reply-To: <202110290755.451B036CE9@keescook> (Kees Cook's message of "Fri,
        29 Oct 2021 07:58:02 -0700")
Message-ID: <87y2665sf8.fsf@disp2133>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux)
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Subject: Re: selftests: seccomp_bpf failure on 5.15
Precedence: bulk

Kees Cook <keescook@chromium.org> writes:

> On Thu, Oct 28, 2021 at 05:06:53PM -0500, Eric W. Biederman wrote:
>> Kees Cook <keescook@chromium.org> writes:
>> 
>> > On Thu, Oct 28, 2021 at 12:26:26PM -0500, Eric W. Biederman wrote:
>> 
>> Is it a problem that the debugger can see the signal if the process does
>> not?
>
> Right, I'm trying to understand that too. However, my neighbor just lost
> power. :|
>
> What I was in the middle of checking was what ptrace "sees" going
> through a fatal SIGSYS; my initial debugging attempts were weird.

Kees have you regained power and had a chance to see my SA_IMMUTABLE
patch?

Does what I implemented seem like it will work for you?

I think it is a solid and simple solution to a pair of problems with my
change to use the ordinary coredump path for seccomp.  But I would very
much love to hear it seems reasonable to you, as you were looking at the
problem as well.

Eric