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 2ED95C352A3 for ; Mon, 10 Feb 2020 13:31:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E265B2085B for ; Mon, 10 Feb 2020 13:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581341508; bh=3RpGryatGBCq6S5c0B9vkCb178y4CrEyAAo+c/YCQ+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CrpV0cPvOmGAP+gXaM64uOVxjetLnOc3mRDHXOZ1HBbPdEvwWX6yTSVN+aZg99iup QZMoFmQF+91mNtKIFJDlNd6/vxPMwytg1Kv5A6Vn/LMa51jL7nBvbUc4r++0gm7D0W R88RkUWS8nUUPlIVw4aXiYiEOdXd8hqYi/EUeZ8A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731377AbgBJNbr (ORCPT ); Mon, 10 Feb 2020 08:31:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:54184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728192AbgBJMf6 (ORCPT ); Mon, 10 Feb 2020 07:35:58 -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 C72C120863; Mon, 10 Feb 2020 12:35:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338157; bh=3RpGryatGBCq6S5c0B9vkCb178y4CrEyAAo+c/YCQ+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E03FGZHbYgXMiiBBufuTIw0SnYEFZlRf7wQvuNBZByuKSbg73/kmgsSFGk/hX6xqs 5EDCl52cQTQ95XwC3b5javU+5cUyLJe6dgjDPUkmtYb/ttFr9QOGY2cVJizkA8uxSt 9wn+248xTq53iGviIKFif2d392jOZZKTSPiQbsQM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nick Finco , Marios Pomonis , Andrew Honig , Jim Mattson , Paolo Bonzini Subject: [PATCH 4.19 126/195] KVM: x86: Protect DR-based index computations from Spectre-v1/L1TF attacks Date: Mon, 10 Feb 2020 04:33:04 -0800 Message-Id: <20200210122317.689295109@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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marios Pomonis commit ea740059ecb37807ba47b84b33d1447435a8d868 upstream. This fixes a Spectre-v1/L1TF vulnerability in __kvm_set_dr() and kvm_get_dr(). Both kvm_get_dr() and kvm_set_dr() (a wrapper of __kvm_set_dr()) are exported symbols so KVM should tream them conservatively from a security perspective. Fixes: 020df0794f57 ("KVM: move DR register access handling into generic code") Signed-off-by: Nick Finco Signed-off-by: Marios Pomonis Reviewed-by: Andrew Honig Cc: stable@vger.kernel.org Reviewed-by: Jim Mattson Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/x86.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -961,9 +961,11 @@ static u64 kvm_dr6_fixed(struct kvm_vcpu static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val) { + size_t size = ARRAY_SIZE(vcpu->arch.db); + switch (dr) { case 0 ... 3: - vcpu->arch.db[dr] = val; + vcpu->arch.db[array_index_nospec(dr, size)] = val; if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) vcpu->arch.eff_db[dr] = val; break; @@ -1000,9 +1002,11 @@ EXPORT_SYMBOL_GPL(kvm_set_dr); int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val) { + size_t size = ARRAY_SIZE(vcpu->arch.db); + switch (dr) { case 0 ... 3: - *val = vcpu->arch.db[dr]; + *val = vcpu->arch.db[array_index_nospec(dr, size)]; break; case 4: /* fall through */