From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932588Ab1DMQJp (ORCPT ); Wed, 13 Apr 2011 12:09:45 -0400 Received: from kroah.org ([198.145.64.141]:54261 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757633Ab1DMPzQ (ORCPT ); Wed, 13 Apr 2011 11:55:16 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Apr 13 08:51:44 2011 Message-Id: <20110413155144.799029367@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 13 Apr 2011 08:50:41 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Julien Tinnes , Roland Dreier Subject: [17/74] Relax si_code check in rt_sigqueueinfo and rt_tgsigqueueinfo In-Reply-To: <20110413155406.GA22568@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Roland Dreier commit 243b422af9ea9af4ead07a8ad54c90d4f9b6081a upstream. Commit da48524eb206 ("Prevent rt_sigqueueinfo and rt_tgsigqueueinfo from spoofing the signal code") made the check on si_code too strict. There are several legitimate places where glibc wants to queue a negative si_code different from SI_QUEUE: - This was first noticed with glibc's aio implementation, which wants to queue a signal with si_code SI_ASYNCIO; the current kernel causes glibc's tst-aio4 test to fail because rt_sigqueueinfo() fails with EPERM. - Further examination of the glibc source shows that getaddrinfo_a() wants to use SI_ASYNCNL (which the kernel does not even define). The timer_create() fallback code wants to queue signals with SI_TIMER. As suggested by Oleg Nesterov , loosen the check to forbid only the problematic SI_TKILL case. Reported-by: Klaus Dittrich Acked-by: Julien Tinnes Signed-off-by: Roland Dreier Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- kernel/signal.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2353,7 +2353,7 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, /* 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 >= 0 || info.si_code == SI_TKILL) { /* We used to allow any < 0 si_code */ WARN_ON_ONCE(info.si_code < 0); return -EPERM; @@ -2373,7 +2373,7 @@ long do_rt_tgsigqueueinfo(pid_t tgid, pi /* 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 >= 0 || info->si_code == SI_TKILL) { /* We used to allow any < 0 si_code */ WARN_ON_ONCE(info->si_code < 0); return -EPERM;