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 785C5C352A3 for ; Mon, 10 Feb 2020 12:59:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 482A820708 for ; Mon, 10 Feb 2020 12:59:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581339554; bh=Xg4iqm6V4qtq84XPRJTH35SoanajKEy1ZkNBZh07Ma8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0FH2pODzX5pjLl8dMqXk2tlgrzwnXOC4JmWkFr5GN1KTAvT7ho9paok4hEHRTiRWK deljgTbl9J6PNLtwnvyw4VkPy/UjqXTJE1N8npG4bm9z/CyiM4C0LBp1f/BChsWfUs USTgRIvGmcVNWIVkYxpnvvRQyfx71C7Klb6T28ao= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730340AbgBJM7N (ORCPT ); Mon, 10 Feb 2020 07:59:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:42928 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729924AbgBJMlM (ORCPT ); Mon, 10 Feb 2020 07:41:12 -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 CF9F220842; Mon, 10 Feb 2020 12:41:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338471; bh=Xg4iqm6V4qtq84XPRJTH35SoanajKEy1ZkNBZh07Ma8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KGHCeGNs7IWnPvlMNVCj9NOvmUBiHpk3GelEnKErv8+6/d4BlXJPHY7DNAa+QaYML gAwF+Ur5C4JFYtia1cDLr8pKRRmYmRbhzneYicpKd4O4lRghGb7KClPTwJrGuXadVu aGyylJWrDa5q8gv6N4qaKcb5Z2EU7+QlqekI/yVY= 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 5.5 237/367] KVM: x86: Protect x86_decode_insn from Spectre-v1/L1TF attacks Date: Mon, 10 Feb 2020 04:32:30 -0800 Message-Id: <20200210122446.064541026@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 3c9053a2cae7ba2ba73766a34cea41baa70f57f7 upstream. This fixes a Spectre-v1/L1TF vulnerability in x86_decode_insn(). kvm_emulate_instruction() (an ancestor of x86_decode_insn()) is an exported symbol, so KVM should treat it conservatively from a security perspective. Fixes: 045a282ca415 ("KVM: emulator: implement fninit, fnstsw, fnstcw") 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/emulate.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5315,10 +5315,15 @@ done_prefixes: } break; case Escape: - if (ctxt->modrm > 0xbf) - opcode = opcode.u.esc->high[ctxt->modrm - 0xc0]; - else + if (ctxt->modrm > 0xbf) { + size_t size = ARRAY_SIZE(opcode.u.esc->high); + u32 index = array_index_nospec( + ctxt->modrm - 0xc0, size); + + opcode = opcode.u.esc->high[index]; + } else { opcode = opcode.u.esc->op[(ctxt->modrm >> 3) & 7]; + } break; case InstrDual: if ((ctxt->modrm >> 6) == 3)