Re: [PATCH 13/20] signal: Implement force_fatal_sig

Kees Cook
2021-10-21T16:24:25Z

On Wed, Oct 20, 2021 at 12:43:59PM -0500, Eric W. Biederman wrote:
> Add a simple helper force_fatal_sig that causes a signal to be
> delivered to a process as if the signal handler was set to SIG_DFL.
>
> Reimplement force_sigsegv based upon this new helper. This fixes
> force_sigsegv so that when it forces the default signal handler
> to be used the code now forces the signal to be unblocked as well.
>
> Reusing the tested logic in force_sig_info_to_task that was built for
> force_sig_seccomp this makes the implementation trivial.
>
> This is interesting both because it makes force_sigsegv simpler and
> because there are a couple of buggy places in the kernel that call
> do_exit(SIGILL) or do_exit(SIGSYS) because there is no straight
> forward way today for those places to simply force the exit of a
> process with the chosen signal. Creating force_fatal_sig allows
> those places to be implemented with normal signal exits.

I assume this is talking about seccomp()? :) Should a patch be included
in this series to change those?

>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

--
Kees Cook