From: ebiederm@xmission.com (Eric W. Biederman)
To: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
Will Drewry <wad@chromium.org>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH 0/2] selftests/seccomp: Report event mismatches more clearly
Date: Wed, 03 Nov 2021 14:17:56 -0500 [thread overview]
Message-ID: <871r3xyrob.fsf@disp2133> (raw)
In-Reply-To: <202111031139.80CE97C532@keescook> (Kees Cook's message of "Wed, 3 Nov 2021 11:40:23 -0700")
Kees Cook <keescook@chromium.org> writes:
> On Wed, Nov 03, 2021 at 01:37:51PM -0500, Eric W. Biederman wrote:
>> Kees Cook <keescook@chromium.org> writes:
>>
>> > Hi,
>> >
>> > This expands the seccomp selftests slightly to add additional debug
>> > reporting detail and a new "immediate fatal SIGSYS under tracing" test.
>> > I expect to be taking these via my seccomp tree.
>>
>> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
>>
>> I am a little fuzzy on the details but I understand what and why
>> you are testing (I broken it). So this is my 10,000 foot ack.
>
> Thanks! Yeah, and the other tests did catch it, but it was kind of a
> "side effect", so I added the specific "direct" case where it can be
> seen more clearly.
Hey. Did you happen to understand the bit about racing with sigaction?
As much as I care about not braking ptrace. What really decided me was
the on SA_IMMUTABLE was closing the race with sigaction changing the
signal handler. Especially for something like seccomp.
It is a race so probably very fickle to write a test for, but if we can
figure out how to write a reliable test I expect it will be a good idea.
Do you have any ideas?
I am concerned there is some threaded program somewhere using seccomp
that is allowed to call sigaction, can use sigaction to keep from
being killed (before I send the fix to Linus).
Eric
prev parent reply other threads:[~2021-11-03 19:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-03 16:30 [PATCH 0/2] selftests/seccomp: Report event mismatches more clearly Kees Cook
2021-11-03 16:30 ` [PATCH 1/2] selftests/seccomp: Stop USER_NOTIF test if kcmp() fails Kees Cook
2021-11-03 16:30 ` [PATCH 2/2] selftests/seccomp: Report event mismatches more clearly Kees Cook
2021-11-03 18:37 ` [PATCH 0/2] " Eric W. Biederman
2021-11-03 18:40 ` Kees Cook
2021-11-03 19:17 ` Eric W. Biederman [this message]
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