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=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 982BFC2BA83 for ; Thu, 13 Feb 2020 16:06:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6EEA1206D7 for ; Thu, 13 Feb 2020 16:06:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581609962; bh=XXb20+cl7ObgXcj/kFd/QmhIqjvVjJSEWhKs5xo0lEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=y0q9NQi6rwYETG4Ztv7W+PSXap0rJQMQUDFTiHL/8QA7+Q4K1U/VGOL6uZrg7evrw LQX8odELuO+n0wqRGszqCsiyhF5kMnBLGM/vNYyAT9xFGb6SkbKOqVNrjjL0EUBeKP /aXASzvtiL3+dinW14P+PNjuDft7xtDVo+W8zQic= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730354AbgBMQGB (ORCPT ); Thu, 13 Feb 2020 11:06:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:35350 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728454AbgBMPXo (ORCPT ); Thu, 13 Feb 2020 10:23:44 -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 3F5212469C; Thu, 13 Feb 2020 15:23:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581607423; bh=XXb20+cl7ObgXcj/kFd/QmhIqjvVjJSEWhKs5xo0lEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d+9h/sHq7jB8HQftmZuCvifaXaDT6CvX2WYkKfjlYAPg9YL9C1BpimlZKqJw8c0mg Eepx12+eUyx5ki543RJF/i3PDw+rFrAQzSjUeyg0Ud5iH5Zpp9WBvfEz41JneoIPa1 1hZ/K4t1HedkF6Trq3oOGGqE2at0jIpmjsD3MEqU= 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 4.9 052/116] KVM: x86: Protect x86_decode_insn from Spectre-v1/L1TF attacks Date: Thu, 13 Feb 2020 07:19:56 -0800 Message-Id: <20200213151903.154634019@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200213151842.259660170@linuxfoundation.org> References: <20200213151842.259660170@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 | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -21,6 +21,7 @@ */ #include +#include #include "kvm_cache_regs.h" #include #include @@ -5158,10 +5159,15 @@ 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)