From: Gabriel Krisman Bertazi <krisman@collabora.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
Al Viro <viro@ZenIV.linux.org.uk>,
Kees Cook <keescook@chromium.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH 14/20] exit/syscall_user_dispatch: Send ordinary signals on failure
Date: Thu, 21 Oct 2021 13:35:40 -0300 [thread overview]
Message-ID: <875ytq1gkj.fsf@collabora.com> (raw)
In-Reply-To: <20211020174406.17889-14-ebiederm@xmission.com> (Eric W. Biederman's message of "Wed, 20 Oct 2021 12:44:00 -0500")
"Eric W. Biederman" <ebiederm@xmission.com> writes:
> Use force_fatal_sig instead of calling do_exit directly. This ensures
> the ordinary signal handling path gets invoked, core dumps as
> appropriate get created, and for multi-threaded processes all of the
> threads are terminated not just a single thread.
>
> When asked Gabriel Krisman Bertazi <krisman@collabora.com> said [1]:
>> ebiederm@xmission.com (Eric W. Biederman) asked:
>>
>> > Why does do_syscal_user_dispatch call do_exit(SIGSEGV) and
>> > do_exit(SIGSYS) instead of force_sig(SIGSEGV) and force_sig(SIGSYS)?
>> >
>> > Looking at the code these cases are not expected to happen, so I would
>> > be surprised if userspace depends on any particular behaviour on the
>> > failure path so I think we can change this.
>>
>> Hi Eric,
>>
>> There is not really a good reason, and the use case that originated the
>> feature doesn't rely on it.
>>
>> Unless I'm missing yet another problem and others correct me, I think
>> it makes sense to change it as you described.
>>
>> > Is using do_exit in this way something you copied from seccomp?
>>
>> I'm not sure, its been a while, but I think it might be just that. The
>> first prototype of SUD was implemented as a seccomp mode.
>
> If at some point it becomes interesting we could relax
> "force_fatal_sig(SIGSEGV)" to instead say
> "force_sig_fault(SIGSEGV, SEGV_MAPERR, sd->selector)".
>
> I avoid doing that in this patch to avoid making it possible
> to catch currently uncatchable signals.
>
> Cc: Gabriel Krisman Bertazi <krisman@collabora.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Andy Lutomirski <luto@kernel.org>
> [1] https://lkml.kernel.org/r/87mtr6gdvi.fsf@collabora.com
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> ---
> kernel/entry/syscall_user_dispatch.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
Hi Eric,
Feel free to add:
Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Thanks,
--
Gabriel Krisman Bertazi
next prev parent reply other threads:[~2021-10-21 16:35 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 17:32 [PATCH 00/20] exit cleanups Eric W. Biederman
2021-10-20 17:43 ` [PATCH 01/20] exit/doublefault: Remove apparently bogus comment about rewind_stack_do_exit Eric W. Biederman
2021-10-21 16:02 ` Kees Cook
2021-10-20 17:43 ` [PATCH 02/20] exit: Remove calls of do_exit after noreturn versions of die Eric W. Biederman
2021-10-21 16:02 ` Kees Cook
2021-10-21 16:25 ` Eric W. Biederman
2021-10-20 17:43 ` [PATCH 03/20] reboot: Remove the unreachable panic after do_exit in reboot(2) Eric W. Biederman
2021-10-21 16:05 ` Kees Cook
2021-10-20 17:43 ` [PATCH 04/20] signal/sparc32: Remove unreachable do_exit in do_sparc_fault Eric W. Biederman
2021-10-21 16:05 ` Kees Cook
2021-10-20 17:43 ` [PATCH 05/20] signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT Eric W. Biederman
2021-10-21 16:06 ` Kees Cook
2021-10-24 4:24 ` Maciej W. Rozycki
2021-10-25 20:55 ` Eric W. Biederman
2021-10-24 15:27 ` Thomas Bogendoerfer
2021-10-20 17:43 ` [PATCH 06/20] signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL) Eric W. Biederman
2021-10-20 19:57 ` Linus Torvalds
2021-10-27 14:24 ` Rich Felker
2021-10-21 16:08 ` Kees Cook
2021-10-20 17:43 ` [PATCH 07/20] signal/powerpc: On swapcontext failure force SIGSEGV Eric W. Biederman
2021-10-21 16:09 ` Kees Cook
2021-10-20 17:43 ` [PATCH 08/20] signal/sparc: In setup_tsb_params convert open coded BUG into BUG Eric W. Biederman
2021-10-21 16:12 ` Kees Cook
2021-10-20 17:43 ` [PATCH 09/20] signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON Eric W. Biederman
2021-10-21 16:15 ` Kees Cook
2021-10-20 17:43 ` [PATCH 10/20] signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved Eric W. Biederman
2021-10-21 16:16 ` Kees Cook
2021-10-21 17:02 ` Eric W. Biederman
2021-10-21 20:33 ` Kees Cook
2021-10-21 23:08 ` Andy Lutomirski
2021-10-24 16:06 ` Eric W. Biederman
[not found] ` <875ytkygfj.fsf_-_@disp2133>
2021-10-25 21:12 ` [PATCH v2 10/32] " Linus Torvalds
2021-10-25 21:28 ` Eric W. Biederman
2021-10-25 22:25 ` Andy Lutomirski
2021-10-25 23:45 ` Linus Torvalds
2021-10-26 0:21 ` Andy Lutomirski
2021-10-20 17:43 ` [PATCH 11/20] signal/s390: Use force_sigsegv in default_trap_handler Eric W. Biederman
2021-10-21 16:17 ` Kees Cook
2021-10-26 9:38 ` Christian Borntraeger
2021-10-28 15:56 ` Eric W. Biederman
2021-10-29 19:32 ` Eric W. Biederman
2021-10-20 17:43 ` [PATCH 12/20] exit/kthread: Have kernel threads return instead of calling do_exit Eric W. Biederman
2021-10-21 11:12 ` Christoph Hellwig
2021-10-21 15:11 ` Eric W. Biederman
2021-10-21 16:21 ` Kees Cook
2021-10-20 17:43 ` [PATCH 13/20] signal: Implement force_fatal_sig Eric W. Biederman
2021-10-20 20:05 ` Linus Torvalds
2021-10-20 21:25 ` Eric W. Biederman
2021-10-25 22:41 ` Andy Lutomirski
2021-10-25 23:15 ` Linus Torvalds
2021-10-26 4:45 ` Eric W. Biederman
2021-10-26 4:57 ` Eric W. Biederman
2021-10-26 16:15 ` Linus Torvalds
2021-10-28 16:33 ` Eric W. Biederman
2021-10-21 16:24 ` Kees Cook
2021-10-21 16:33 ` Eric W. Biederman
2021-10-21 16:39 ` Kees Cook
2021-10-20 17:44 ` [PATCH 14/20] exit/syscall_user_dispatch: Send ordinary signals on failure Eric W. Biederman
2021-10-21 16:25 ` Kees Cook
2021-10-21 16:37 ` Eric W. Biederman
2021-10-21 16:40 ` Kees Cook
2021-10-21 17:05 ` Eric W. Biederman
2021-10-25 22:32 ` Andy Lutomirski
2021-10-21 16:35 ` Gabriel Krisman Bertazi [this message]
2021-10-20 17:44 ` [PATCH 15/20] signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails Eric W. Biederman
2021-10-21 16:34 ` Kees Cook
2021-10-21 16:56 ` Eric W. Biederman
2021-10-20 17:44 ` [PATCH 16/20] signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig Eric W. Biederman
2021-10-21 16:34 ` Kees Cook
2021-10-20 17:44 ` [PATCH 17/20] signal/x86: In emulate_vsyscall force a signal instead of calling do_exit Eric W. Biederman
2021-10-21 16:36 ` Kees Cook
2021-10-20 17:44 ` [PATCH 18/20] exit/rtl8723bs: Replace the macro thread_exit with a simple return 0 Eric W. Biederman
2021-10-21 7:06 ` Greg KH
2021-10-21 15:06 ` Eric W. Biederman
2021-10-21 16:37 ` Kees Cook
2021-10-20 17:44 ` [PATCH 19/20] exit/rtl8712: " Eric W. Biederman
2021-10-21 7:07 ` Greg KH
2021-10-21 16:37 ` Kees Cook
2021-10-20 17:44 ` [PATCH 20/20] exit/r8188eu: " Eric W. Biederman
2021-10-21 7:07 ` Greg KH
2021-10-21 16:37 ` Kees Cook
2021-10-20 21:51 ` [PATCH 21/20] signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV) Eric W. Biederman
2021-10-21 8:09 ` Geert Uytterhoeven
2021-10-21 13:33 ` Eric W. Biederman
2021-10-21 8:32 ` Philippe Mathieu-Daudé
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