From patchwork Mon Feb 10 12:33:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 232031 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=ham 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 4A14CC352A3 for ; Mon, 10 Feb 2020 12:36:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 195812465D for ; Mon, 10 Feb 2020 12:36:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338160; bh=giC4kPqCAkEv4uVEpJI14NzZauFjfN0qIk1iIX1ADu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gkJpUpU29BVdbXfG3W4eJRVpQflPHsp/2b2bm5pkigojm+vfviUGvzB78J4oyWh6j /0pyG3krFjuTtgoqDFI4xy5kTXQIzc/EuRxBsXVNDeOOABP/CWjQXOdqQgB46urAhT IWyMllyOecKT6wbCpeSU5xF5GpIhlsJEVbjUZlms= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728194AbgBJMf6 (ORCPT ); Mon, 10 Feb 2020 07:35:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:54258 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728186AbgBJMf5 (ORCPT ); Mon, 10 Feb 2020 07:35:57 -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 C5EB020842; Mon, 10 Feb 2020 12:35:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338156; bh=giC4kPqCAkEv4uVEpJI14NzZauFjfN0qIk1iIX1ADu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Dy8T1fmDe07osp+sn+3T4ZRLFy2RQOHpPOiHlvLzXWjJ+6Q7Uu5IkHLyhYeNw5q07 ng2W/qWl5lqR8h+Pbrri0vpxpLKpUaqGyvTH8KuwNZpc9sTxINvTgPrU4nI+MVk5Ax BzOv5NFdw1Vh9T9svGDZGSHKFzd9w/tRADrrYzNw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Bonzini Subject: [PATCH 4.19 124/195] KVM: x86: Refactor prefix decoding to prevent Spectre-v1/L1TF attacks Date: Mon, 10 Feb 2020 04:33:02 -0800 Message-Id: <20200210122317.508860753@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 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Marios Pomonis commit 125ffc5e0a56a3eded608dc51e09d5ebf72cf652 upstream. This fixes Spectre-v1/L1TF vulnerabilities in vmx_read_guest_seg_selector(), vmx_read_guest_seg_base(), vmx_read_guest_seg_limit() and vmx_read_guest_seg_ar(). When invoked from emulation, these functions contain index computations based on the (attacker-influenced) segment value. Using constants prevents the attack. Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/emulate.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5164,16 +5164,28 @@ int x86_decode_insn(struct x86_emulate_c ctxt->ad_bytes = def_ad_bytes ^ 6; break; case 0x26: /* ES override */ + has_seg_override = true; + ctxt->seg_override = VCPU_SREG_ES; + break; case 0x2e: /* CS override */ + has_seg_override = true; + ctxt->seg_override = VCPU_SREG_CS; + break; case 0x36: /* SS override */ + has_seg_override = true; + ctxt->seg_override = VCPU_SREG_SS; + break; case 0x3e: /* DS override */ has_seg_override = true; - ctxt->seg_override = (ctxt->b >> 3) & 3; + ctxt->seg_override = VCPU_SREG_DS; break; case 0x64: /* FS override */ + has_seg_override = true; + ctxt->seg_override = VCPU_SREG_FS; + break; case 0x65: /* GS override */ has_seg_override = true; - ctxt->seg_override = ctxt->b & 7; + ctxt->seg_override = VCPU_SREG_GS; break; case 0x40 ... 0x4f: /* REX */ if (mode != X86EMUL_MODE_PROT64)