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From: Oleg Nesterov <oleg@redhat.com>
To: Roland Dreier <roland@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel@vger.kernel.org, Julien Tinnes <jln@google.com>,
	Klaus Dittrich <kladit@arcor.de>
Subject: Re: [PATCH] Allow rt_sigqueueinfo and rt_tgsigqueueinfo to use si_code == SI_ASYNCIO
Date: Mon, 28 Mar 2011 19:42:30 +0200	[thread overview]
Message-ID: <20110328174230.GB11649@redhat.com> (raw)
In-Reply-To: <1301336640-16348-1-git-send-email-roland@kernel.org>

On 03/28, Roland Dreier wrote:
>
> Commit da48524eb206 ("Prevent rt_sigqueueinfo and rt_tgsigqueueinfo
> from spoofing the signal code") made the check on si_code too strict:
> glibc's aio implementation wants to queue signals with SI_ASYNCIO, and
> indeed glibc's tst-aio4 fails with the patched kernel.
>
> Fix this by loosening the new check to allow SI_ASYNCIO as well.

Heh.

> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -2437,7 +2437,7 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
>  	/* Not even root can pretend to send signals from the kernel.
>  	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
>  	 */
> -	if (info.si_code != SI_QUEUE) {
> +	if (info.si_code != SI_QUEUE && info.si_code != SI_ASYNCIO) {

I am starting to think that "plan B" was better.

	if (info.si_code >= 0 || info.si_code == SI_TKILL)
		return -EPERM;

Although we should probably keep WARN_ON_ONCE() anyway.

Oleg.


  reply	other threads:[~2011-03-28 18:52 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-28 18:24 [PATCH] Allow rt_sigqueueinfo and rt_tgsigqueueinfo to use si_code == SI_ASYNCIO Roland Dreier
2011-03-28 17:42 ` Oleg Nesterov [this message]
2011-03-28 20:27   ` Roland Dreier

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