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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 16FBAC4332D for ; Thu, 19 Mar 2020 09:17:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E08D520724 for ; Thu, 19 Mar 2020 09:17:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727477AbgCSJRW (ORCPT ); Thu, 19 Mar 2020 05:17:22 -0400 Received: from 8bytes.org ([81.169.241.247]:52476 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727406AbgCSJOj (ORCPT ); Thu, 19 Mar 2020 05:14:39 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 9157DA75; Thu, 19 Mar 2020 10:14:24 +0100 (CET) From: Joerg Roedel To: x86@kernel.org Cc: hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Thomas Hellstrom , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Joerg Roedel , Joerg Roedel Subject: [PATCH 44/70] x86/sev-es: Handle instruction fetches from user-space Date: Thu, 19 Mar 2020 10:13:41 +0100 Message-Id: <20200319091407.1481-45-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200319091407.1481-1-joro@8bytes.org> References: <20200319091407.1481-1-joro@8bytes.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel When a #VC exception is triggered by user-space the instruction decoder needs to read the instruction bytes from user addresses. Enhance vc_decode_insn() to safely fetch kernel and user instructions. Signed-off-by: Joerg Roedel --- arch/x86/kernel/sev-es.c | 31 ++++++++++++++++++++++--------- 1 file changed, 22 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 226ab0c57a09..79a71d14a1fc 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -114,17 +114,30 @@ static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt) enum es_result ret; int res; - res = vc_fetch_insn_kernel(ctxt, buffer); - if (unlikely(res == -EFAULT)) { - ctxt->fi.vector = X86_TRAP_PF; - ctxt->fi.error_code = 0; - ctxt->fi.cr2 = ctxt->regs->ip; - return ES_EXCEPTION; + if (!user_mode(ctxt->regs)) { + res = vc_fetch_insn_kernel(ctxt, buffer); + if (unlikely(res == -EFAULT)) { + ctxt->fi.vector = X86_TRAP_PF; + ctxt->fi.error_code = 0; + ctxt->fi.cr2 = ctxt->regs->ip; + return ES_EXCEPTION; + } + + insn_init(&ctxt->insn, buffer, MAX_INSN_SIZE - res, 1); + insn_get_length(&ctxt->insn); + } else { + res = insn_fetch_from_user(ctxt->regs, buffer); + if (res == 0) { + ctxt->fi.vector = X86_TRAP_PF; + ctxt->fi.cr2 = ctxt->regs->ip; + ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; + return ES_EXCEPTION; + } + + if (!insn_decode(ctxt->regs, &ctxt->insn, buffer, res)) + return ES_DECODE_FAILED; } - insn_init(&ctxt->insn, buffer, MAX_INSN_SIZE - res, 1); - insn_get_length(&ctxt->insn); - ret = ctxt->insn.immediate.got ? ES_OK : ES_DECODE_FAILED; return ret; -- 2.17.1