Received: by 2002:a25:c593:0:0:0:0:0 with SMTP id v141csp6235736ybe; Tue, 17 Sep 2019 23:31:38 -0700 (PDT) X-Google-Smtp-Source: APXvYqypO/Wtu2pC90fUdQt+T3kD/VUP5k5l6jBJurphdF2L4oZEl3UTywBzoo5fWooN1jlyu9vS X-Received: by 2002:a17:906:85c8:: with SMTP id i8mr8223383ejy.178.1568788298146; Tue, 17 Sep 2019 23:31:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1568788298; cv=none; d=google.com; s=arc-20160816; b=BLsSZys3EKeEXL0aVGWmNvSfKw7Z+/VJDqCgTXWf7dGVJGKczwqetudjt9TpioupJC iQxfMaYjWq4wKHksNL3EqrEOGDYTiz0ax7G6NDpSGmNHSnF8WVSBk5AKwH3j+XKWQ9Rg 9QEvinUjN8EBJ6eEkJbsnkcXY16kubGI51FP6/Pbl3QzkjCLaWtBK6Kb8VMjhj168ik5 VOwChdSl+/L8uCkSpOIK4+HjH05rp6huummKGOwYmPZi6rZMr/mj9y+ii8OTPePW88cG q8e8NCGOYq55gra1iEKTnWMpQek8vv6ZKJMa0PZaYdbgEejEeUYwPI8nVRqXnTPE8O7f BDEw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=fO5J+LZMtdj2qgyjjstx+4EZvAsRp3ol0danL0QUuR8=; b=q9wvDoh8RZZMQnBaVvHCFcV7yu11zQbadqoJG0J/YuYM61mTdA/QMZGPSvU6Yh0ipQ qmBZ/UoskrM4a1cl4hfQTooLZJ+ks7iccGr8SMaT3/XTxbfc6hDi9fMYrQGPsIsQN7vc zf6KQ+g/BV4/fGPgJuOh0luH4lemf5qbx/qnkXTAqlMbOYgNf7IOuNpQOb5EU8gs5Wvh PCkTBeacn6/curMeJSG0c2xMuf+JAUOdj7Tfj/2xwXPXh7vQfhJ4JW1Xfsl8wr7g/muZ 3DwyZ333qe57nZkBXZalIYfCJ47tQUr1EKu0C/5HiY/zwfel9AWleBCvryP4EOg7H3WG ArjA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=KSxK4elr; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id b44si2731497ede.451.2019.09.17.23.31.15; Tue, 17 Sep 2019 23:31:38 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=KSxK4elr; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729778AbfIRG1s (ORCPT + 99 others); Wed, 18 Sep 2019 02:27:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:49724 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729753AbfIRG1m (ORCPT ); Wed, 18 Sep 2019 02:27:42 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 53A1821924; Wed, 18 Sep 2019 06:27:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568788061; bh=6Bp66dhnguOvsj+AWTcuGX7grWtd/Ey3/k8Ya37DBto=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KSxK4elrWiyvXa7Js6p7hbLI49WF/XwhrvOOtytVo88nPGu8TboAWTNaCda5VL6pj 5kZPD2CSzBVMyD29AQPkn83d9ncjrmYS2VUklq9BLC2xry42NrSD08kAAqVqYzaDo7 6svomaVoznjWH8EhuUK9x13TZ1EquGdXpkSMXuOI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Fuqian Huang , Paolo Bonzini Subject: [PATCH 5.2 45/85] KVM: x86: work around leak of uninitialized stack contents Date: Wed, 18 Sep 2019 08:19:03 +0200 Message-Id: <20190918061235.562781847@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190918061234.107708857@linuxfoundation.org> References: <20190918061234.107708857@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Fuqian Huang commit 541ab2aeb28251bf7135c7961f3a6080eebcc705 upstream. Emulation of VMPTRST can incorrectly inject a page fault when passed an operand that points to an MMIO address. The page fault will use uninitialized kernel stack memory as the CR2 and error code. The right behavior would be to abort the VM with a KVM_EXIT_INTERNAL_ERROR exit to userspace; however, it is not an easy fix, so for now just ensure that the error code and CR2 are zero. Signed-off-by: Fuqian Huang Cc: stable@vger.kernel.org [add comment] Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5265,6 +5265,13 @@ int kvm_write_guest_virt_system(struct k /* kvm_write_guest_virt_system can pull in tons of pages. */ vcpu->arch.l1tf_flush_l1d = true; + /* + * FIXME: this should call handle_emulation_failure if X86EMUL_IO_NEEDED + * is returned, but our callers are not ready for that and they blindly + * call kvm_inject_page_fault. Ensure that they at least do not leak + * uninitialized kernel stack memory into cr2 and error code. + */ + memset(exception, 0, sizeof(*exception)); return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, PFERR_WRITE_MASK, exception); }