From: [email protected] (Eric W. Biederman)
To: Jens Axboe <[email protected]>
Cc: [email protected], [email protected],
[email protected], [email protected],
Stefan Metzmacher <[email protected]>
Subject: Re: [PATCH 1/2] signal: don't allow sending any signals to PF_IO_WORKER threads
Date: Sat, 20 Mar 2021 11:18:29 -0500 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]> (Jens Axboe's message of "Sat, 20 Mar 2021 09:38:31 -0600")
Jens Axboe <[email protected]> writes:
> They don't take signals individually, and even if they share signals with
> the parent task, don't allow them to be delivered through the worker
> thread.
This is silly I know, but why do we care?
The creds should be reasonably in-sync with the rest of the threads.
There are other threads that will receive the signal, especially when
you worry about group_send_sig_info. Which signal sending code paths
are actually a problem.
> Reported-by: Stefan Metzmacher <[email protected]>
> Signed-off-by: Jens Axboe <[email protected]>
> ---
> kernel/signal.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/signal.c b/kernel/signal.c
> index ba4d1ef39a9e..730ecd3d6faf 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -833,6 +833,9 @@ static int check_kill_permission(int sig, struct kernel_siginfo *info,
>
> if (!valid_signal(sig))
> return -EINVAL;
> + /* PF_IO_WORKER threads don't take any signals */
> + if (t->flags & PF_IO_WORKER)
> + return -EPERM;
>
> if (!si_fromuser(info))
> return 0;
next prev parent reply other threads:[~2021-03-20 16:20 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-20 15:38 [PATCHSET 0/2] PF_IO_WORKER signal tweaks Jens Axboe
2021-03-20 15:38 ` [PATCH 1/2] signal: don't allow sending any signals to PF_IO_WORKER threads Jens Axboe
2021-03-20 16:18 ` Eric W. Biederman [this message]
2021-03-20 17:56 ` Linus Torvalds
2021-03-20 21:38 ` Eric W. Biederman
2021-03-20 22:42 ` Jens Axboe
2021-03-21 14:54 ` Eric W. Biederman
2021-03-21 15:40 ` Jens Axboe
2021-03-20 15:38 ` [PATCH 2/2] signal: don't allow STOP on " Jens Axboe
2021-03-20 16:21 ` Eric W. Biederman
2021-03-22 16:18 ` Oleg Nesterov
2021-03-22 16:15 ` Oleg Nesterov
2021-03-20 16:26 ` [PATCHSET 0/2] PF_IO_WORKER signal tweaks Eric W. Biederman
2021-03-20 17:51 ` Linus Torvalds
2021-03-20 19:18 ` Linus Torvalds
2021-03-20 22:08 ` Eric W. Biederman
2021-03-20 22:53 ` Jens Axboe
2021-03-21 15:18 ` Eric W. Biederman
2021-03-21 15:42 ` Jens Axboe
2021-03-20 22:56 ` Jens Axboe
2021-03-20 17:05 ` kernel test robot
2021-03-20 17:05 ` kernel test robot
2021-03-20 19:10 ` kernel test robot
2021-03-22 16:05 ` Oleg Nesterov
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