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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 6F89BC433E0 for ; Wed, 20 May 2020 14:25:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4AB01207D4 for ; Wed, 20 May 2020 14:25:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728338AbgETOZM (ORCPT ); Wed, 20 May 2020 10:25:12 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33078 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727027AbgETOW1 (ORCPT ); Wed, 20 May 2020 10:22:27 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jbPby-000376-D9; Wed, 20 May 2020 15:22:22 +0100 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1jbPbx-007DVJ-4A; Wed, 20 May 2020 15:22:21 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Marios Pomonis" , "Nick Finco" , "Jim Mattson" , "Paolo Bonzini" , "Andrew Honig" Date: Wed, 20 May 2020 15:14:48 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 80/99] KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF attacks In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.84-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Marios Pomonis commit 4bf79cb089f6b1c6c632492c0271054ce52ad766 upstream. This fixes a Spectre-v1/L1TF vulnerability in kvm_lapic_reg_write(). This function contains index computations based on the (attacker-controlled) MSR number. Fixes: 0105d1a52640 ("KVM: x2apic interface to lapic") Signed-off-by: Nick Finco Signed-off-by: Marios Pomonis Reviewed-by: Andrew Honig Reviewed-by: Jim Mattson Signed-off-by: Paolo Bonzini [bwh: Backported to 3.16: - Add #include - Adjust context] Signed-off-by: Ben Hutchings --- --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -35,6 +35,7 @@ #include #include #include +#include #include "kvm_cache_regs.h" #include "irq.h" #include "trace.h" @@ -1196,15 +1197,20 @@ static int apic_reg_write(struct kvm_lap case APIC_LVTTHMR: case APIC_LVTPC: case APIC_LVT1: - case APIC_LVTERR: + case APIC_LVTERR: { /* TODO: Check vector */ + size_t size; + u32 index; + if (!kvm_apic_sw_enabled(apic)) val |= APIC_LVT_MASKED; - - val &= apic_lvt_mask[(reg - APIC_LVTT) >> 4]; + size = ARRAY_SIZE(apic_lvt_mask); + index = array_index_nospec( + (reg - APIC_LVTT) >> 4, size); + val &= apic_lvt_mask[index]; apic_set_reg(apic, reg, val); - break; + } case APIC_LVTT: if ((kvm_apic_get_reg(apic, APIC_LVTT) &