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,URIBL_BLOCKED,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 3F756C2BA83 for ; Thu, 13 Feb 2020 16:09:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0DC5E206ED for ; Thu, 13 Feb 2020 16:09:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581610174; bh=0iu1mtL/dPB7ua2msYJlQENzi50mFh/OXAG/DxLqoTQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=E+G2i4nq4wkVc0Wp1t8lno+VVEYq0GO7Ch1P6n05wj1/9XSJDt+NMBmyPMrdFprAN 0aXqNw6krhbTzlwNvkxXbra3FLiRo8H7CPobsRfcdBaVSczyhQyoz8Hy0fQAuQ3Yqy lXfXRi4mk5BYMQQfr5Xe9f//mWCCbXP6KolvhSC8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728100AbgBMPWp (ORCPT ); Thu, 13 Feb 2020 10:22:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:60154 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727982AbgBMPWf (ORCPT ); Thu, 13 Feb 2020 10:22:35 -0500 Received: from localhost (unknown [104.132.1.104]) (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 342DD24689; Thu, 13 Feb 2020 15:22:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581607353; bh=0iu1mtL/dPB7ua2msYJlQENzi50mFh/OXAG/DxLqoTQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vu2i7SBcP/9LwW0JYBIlwjNdK/hv1JMYdG5av8DsLH81TOHhB86w1C+LLSmFMTI+O uGcJapGHpN1JwS+gOQhnDimGmKA0EzkFuuxmvkLSZ9DyjeRyb6vdYYiqlU3x1oowST ANG0XlsOkOdO8dglGgaUxgnuCHGvIUrRGNBsEW6M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Bonzini Subject: [PATCH 4.4 35/91] KVM: x86: Refactor prefix decoding to prevent Spectre-v1/L1TF attacks Date: Thu, 13 Feb 2020 07:19:52 -0800 Message-Id: <20200213151835.142777176@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200213151821.384445454@linuxfoundation.org> References: <20200213151821.384445454@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: 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 @@ -5041,16 +5041,28 @@ 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)