From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA135C352A5 for ; Mon, 10 Feb 2020 13:31:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7786A20714 for ; Mon, 10 Feb 2020 13:31:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581341482; bh=IYzxdXsmudUkeoX+3056nzpQ6OHR3iAIkWE89utgMGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YI+v4eyNNTgAWrRswtsFLyd+/3KQMk7GUZtXEYNqp3fZjKWZEgfHJ1dOtWbR8Vcyc Dtt/bdvBmUGghtTte5COTK3Wh1YTqX6e+DhAzDZsI+9CvfC/hjeOrIbOwkjHPmJUUN axVZ3i0PWn6sB1jtah6rSmeS78OeB16Eh8NpknjY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731415AbgBJNbO (ORCPT ); Mon, 10 Feb 2020 08:31:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:54558 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728222AbgBJMgD (ORCPT ); Mon, 10 Feb 2020 07:36:03 -0500 Received: from localhost (unknown [209.37.97.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 64CDE20842; Mon, 10 Feb 2020 12:36:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338162; bh=IYzxdXsmudUkeoX+3056nzpQ6OHR3iAIkWE89utgMGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AbVc5IfCCM9aNLxEh978GfAErBGwKz7BhjTjkOIkDHC7LPLPWFj2s55BUD3+ZxEom cICxsIdzfAr86SiWFXDi1EIV2/W8rdyNf2W2a6zvyVFtV2dJGLfltf2xiC8XlUq++1 6NnhJl6lVU1cWxZO0WFDqvfV+FHN0YWVzH9Nd4MU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Boris Ostrovsky , Joao Martins , Paolo Bonzini Subject: [PATCH 4.19 138/195] x86/kvm: Be careful not to clear KVM_VCPU_FLUSH_TLB bit Date: Mon, 10 Feb 2020 04:33:16 -0800 Message-Id: <20200210122318.794552975@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122305.731206734@linuxfoundation.org> References: <20200210122305.731206734@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Boris Ostrovsky commit 8c6de56a42e0c657955e12b882a81ef07d1d073e upstream. kvm_steal_time_set_preempted() may accidentally clear KVM_VCPU_FLUSH_TLB bit if it is called more than once while VCPU is preempted. This is part of CVE-2019-3016. (This bug was also independently discovered by Jim Mattson ) Signed-off-by: Boris Ostrovsky Reviewed-by: Joao Martins Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3244,6 +3244,9 @@ static void kvm_steal_time_set_preempted if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) return; + if (vcpu->arch.st.steal.preempted) + return; + vcpu->arch.st.steal.preempted = KVM_VCPU_PREEMPTED; kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime,