linux-kernel - Re: [patch V2 26/50] signal: Get rid of resched

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240418163811.GA23440@redhat.com>
Date: Thu, 18 Apr 2024 18:38:11 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
	Anna-Maria Behnsen <anna-maria@...utronix.de>,
	Frederic Weisbecker <frederic@...nel.org>,
	John Stultz <jstultz@...gle.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, Stephen Boyd <sboyd@...nel.org>,
	Eric Biederman <ebiederm@...ssion.com>
Subject: Re: [patch V2 26/50] signal: Get rid of resched_timer logic

On 04/11, Thomas Gleixner wrote:
>
> There is no reason for handing the *resched pointer argument through
> several functions just to check whether the signal is related to a self
> rearming posix timer.

Agreed, these changes looks good to me.

But,

> SI_TIMER is only used by the posix timer code and cannot be queued from
> user space.

Why? I think sigqueueinfo() can certainly use si_code = SI_TIMER, so

> @@ -1011,6 +1001,9 @@ static int __send_signal_locked(int sig,
>  
>  	lockdep_assert_held(&t->sighand->siglock);
>  
> +	if (WARN_ON_ONCE(!is_si_special(info) && info->si_code == SI_TIMER))
> +		return 0;

this can be easily triggered by userspace and thus looks wrong.

Oleg.