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From: Kees Cook <keescook@chromium.org>
To: Kyle Huey <me@kylehuey.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	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>,
	"open list:KERNEL SELFTEST FRAMEWORK" 
	<linux-kselftest@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	linux-hardening@vger.kernel.org,
	Robert O'Callahan <rocallahan@gmail.com>
Subject: Re: [REGRESSION] 5.16rc1: SA_IMMUTABLE breaks debuggers
Date: Wed, 17 Nov 2021 17:32:20 -0800	[thread overview]
Message-ID: <202111171728.D85A4E2571@keescook> (raw)
In-Reply-To: <CAP045AoqssLTKOqse1t1DG1HgK9h+goG8C3sqgOyOV3Wwq+LDA@mail.gmail.com>

On Wed, Nov 17, 2021 at 05:20:33PM -0800, Kyle Huey wrote:
> Yeah that's one way to solve the problem. I think you're right that
> fundamentally the problem here is that what SECCOMP_RET_KILL wants is
> not really a signal. To the extent that it wants a signal, what it
> really wants is SIGKILL, and the problem here is the code trying to
> act like SIGKILL but call it SIGSYS. I assume the ship for fixing that
> sailed years ago though.

Yeah, this was IIRC, a specific design choice (to distinguish a seccomp
KILL from a SIGKILL), as desired by the sandboxing folks, and instead
of using two different signals (one for KILL and one for TRAP), both
used SIGSYS, with the KILL variant being uncatchable.

-- 
Kees Cook

  reply	other threads:[~2021-11-18  1:32 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-17 18:47 Kyle Huey
2021-11-17 18:51 ` Kees Cook
2021-11-17 19:05   ` Kyle Huey
2021-11-17 19:09     ` Kyle Huey
2021-11-17 21:04       ` Eric W. Biederman
2021-11-17 21:54         ` Kees Cook
2021-11-17 23:24           ` Linus Torvalds
2021-11-18  0:05             ` Kees Cook
2021-11-18  0:15               ` Linus Torvalds
2021-11-18  0:37             ` Kyle Huey
2021-11-18  1:11               ` Linus Torvalds
2021-11-18  1:20                 ` Kyle Huey
2021-11-18  1:32                   ` Kees Cook [this message]
2021-11-18 16:10                     ` Eric W. Biederman
2021-11-19 16:07                       ` Kyle Huey
2021-11-19 16:35                         ` Kees Cook
2021-11-19 16:58                           ` Kyle Huey
2021-11-18 21:58                     ` [PATCH 0/2] SA_IMMUTABLE fixes Eric W. Biederman
2021-11-18 22:04                       ` [PATCH 1/2] signal: Don't always set SA_IMMUTABLE for forced signals Eric W. Biederman
2021-11-18 23:52                         ` Kees Cook
2021-11-18 23:54                         ` Kees Cook
2021-11-19 15:08                           ` Eric W. Biederman
2021-11-19  1:13                         ` Kyle Huey
2021-11-19 15:03                           ` Eric W. Biederman
2021-11-18 22:05                       ` [PATCH 2/2] signal: Replace force_fatal_sig with force_exit_sig when in doubt Eric W. Biederman
2021-11-18 23:53                         ` Kees Cook
2021-11-19  1:12                       ` [PATCH 0/2] SA_IMMUTABLE fixes Kyle Huey
2021-11-19 15:41                         ` [GIT PULL] SA_IMMUTABLE fixes for v5.16-rc2 Eric W. Biederman
2021-11-19 19:46                           ` pr-tracker-bot
2021-11-17 22:29         ` [REGRESSION] 5.16rc1: SA_IMMUTABLE breaks debuggers Kyle Huey
2021-11-18  5:43 ` Thorsten Leemhuis
2021-11-20  6:13   ` Thorsten Leemhuis

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