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 7E1AAC352A3 for ; Mon, 10 Feb 2020 12:45:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B26B2051A for ; Mon, 10 Feb 2020 12:45:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338750; bh=ZB7sIyLLF5dzwWVS/9ZihNmuzaaoQdbJSZEp8Y5qgkg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=S7NBbjvtnzIEUNrsifbcmhH3AeKCiy0XuzHp7cIFHpxZzuXFC124Hn5P4JUWJeOuD bsvz00XWIxNCzfkndQBLKTspyKbbS3UdbwFiLqAZDv0O+wSpIeCLW25Fil9mH6KqKN OvAEZPrbYKIdUgvMY9EYsoZr92XD4u8B/0H9v22E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728702AbgBJMps (ORCPT ); Mon, 10 Feb 2020 07:45:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:42618 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729892AbgBJMlH (ORCPT ); Mon, 10 Feb 2020 07:41:07 -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 BE1DE2085B; Mon, 10 Feb 2020 12:41:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338466; bh=ZB7sIyLLF5dzwWVS/9ZihNmuzaaoQdbJSZEp8Y5qgkg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PumI1SKe8m0+m369P4vLSbYt74CKHYzxcMQIvtg5oUWzY/B+VR7EyUM2Kgw6lS9yP 4CszyMpUznaHvhpxQ0ir9xD8pue9Fz4MRMeRCr0xY3/9bKL/QOETgchnmjTvT6P/tN YCasfJJmoXx6ZaYB6loofPz7/5YGnQmXBZBNch48= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Bonzini Subject: [PATCH 5.5 228/367] KVM: x86: Refactor prefix decoding to prevent Spectre-v1/L1TF attacks Date: Mon, 10 Feb 2020 04:32:21 -0800 Message-Id: <20200210122445.417308332@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122423.695146547@linuxfoundation.org> References: <20200210122423.695146547@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 @@ -5210,16 +5210,28 @@ 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)