Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933008AbaJXPHr (ORCPT ); Fri, 24 Oct 2014 11:07:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:14922 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932860AbaJXPHj (ORCPT ); Fri, 24 Oct 2014 11:07:39 -0400 From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Andy Honig , stable@vger.kernel.org Subject: [PATCH 03/14] KVM: x86: Improve thread safety in pit Date: Fri, 24 Oct 2014 17:07:14 +0200 Message-Id: <1414163245-18555-4-git-send-email-pbonzini@redhat.com> In-Reply-To: <1414163245-18555-1-git-send-email-pbonzini@redhat.com> References: <1414163245-18555-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Honig There's a race condition in the PIT emulation code in KVM. In __kvm_migrate_pit_timer the pit_timer object is accessed without synchronization. If the race condition occurs at the wrong time this can crash the host kernel. This fixes CVE-2014-3611. Cc: stable@vger.kernel.org Signed-off-by: Andrew Honig Signed-off-by: Paolo Bonzini --- arch/x86/kvm/i8254.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 518d86471b76..298781d4cfb4 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -262,8 +262,10 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu) return; timer = &pit->pit_state.timer; + mutex_lock(&pit->pit_state.lock); if (hrtimer_cancel(timer)) hrtimer_start_expires(timer, HRTIMER_MODE_ABS); + mutex_unlock(&pit->pit_state.lock); } static void destroy_pit_timer(struct kvm_pit *pit) -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/