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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 E72E2C5B579 for ; Fri, 28 Jun 2019 09:34:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBB50214AF for ; Fri, 28 Jun 2019 09:34:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="NijCFQlk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726574AbfF1JeF (ORCPT ); Fri, 28 Jun 2019 05:34:05 -0400 Received: from smtp-fw-6002.amazon.com ([52.95.49.90]:17969 "EHLO smtp-fw-6002.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726385AbfF1JeF (ORCPT ); Fri, 28 Jun 2019 05:34:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1561714444; x=1593250444; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=sSKEUVaTdyL6t5ZO2NW3uKuh1AeVNjk+FHaRRO4KGtI=; b=NijCFQlkyyK7FfvWXmgNHYE0bJIap9oSNNMq9l6hELAx5Xct/iEnSozP WkQW7lzlLaMbI/nG3tC97HAqXxEjfLXGLsM77tWoMtnkewrXJexAWsAzG mBrZeFi0Ti4udYx8FrRDm79mYVNZv1ChSOsk+lbJq2gBn/pUAQ2dcWifl M=; X-IronPort-AV: E=Sophos;i="5.62,427,1554768000"; d="scan'208";a="408520324" Received: from iad6-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-1e-97fdccfd.us-east-1.amazon.com) ([10.124.125.6]) by smtp-border-fw-out-6002.iad6.amazon.com with ESMTP; 28 Jun 2019 09:33:56 +0000 Received: from EX13MTAUWC001.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan2.iad.amazon.com [10.40.159.162]) by email-inbound-relay-1e-97fdccfd.us-east-1.amazon.com (Postfix) with ESMTPS id EB7E1A1DFF; Fri, 28 Jun 2019 09:33:52 +0000 (UTC) Received: from EX13D20UWC001.ant.amazon.com (10.43.162.244) by EX13MTAUWC001.ant.amazon.com (10.43.162.135) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Fri, 28 Jun 2019 09:33:51 +0000 Received: from 38f9d3867b82.ant.amazon.com (10.43.161.16) by EX13D20UWC001.ant.amazon.com (10.43.162.244) with Microsoft SMTP Server (TLS) id 15.0.1367.3; Fri, 28 Jun 2019 09:33:47 +0000 Subject: Re: [PATCH v4 0/5] x86 instruction emulator fuzzing To: Sam Caccavale CC: , , , , , , , , , , , , , , , , , References: <20190628092621.17823-1-samcacc@amazon.de> From: Alexander Graf Message-ID: Date: Fri, 28 Jun 2019 11:33:45 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190628092621.17823-1-samcacc@amazon.de> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.43.161.16] X-ClientProxiedBy: EX13D18UWC004.ant.amazon.com (10.43.162.77) To EX13D20UWC001.ant.amazon.com (10.43.162.244) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 28.06.19 11:26, Sam Caccavale wrote: > Dear all, > > This series aims to provide an entrypoint for, and fuzz KVM's x86 instruction > emulator from userspace. It mirrors Xen's application of the AFL fuzzer to > it's instruction emulator in the hopes of discovering vulnerabilities. > Since this entrypoint also allows arbitrary execution of the emulators code > from userspace, it may also be useful for testing. > > The current 4 patches build the emulator and 2 harnesses: simple-harness is > an example of unit testing; afl-harness is a frontend for the AFL fuzzer. > The fifth patch contains useful scripts for development but is not intended > for usptream consumption. > > Patches > ======= > > - 01: Builds and links afl-harness with the required kernel objects. > - 02: Introduces the minimal set of emulator operations and supporting code > to emulate simple instructions. > - 03: Demonstrates simple-harness as a unit test. > - 04: Adds scripts for install and building. > - 05: Useful scripts for development > > > Issues > ======= > > Currently, fuzzing results in a large amount of FPU related crashes. Xen's > fuzzing efforts had this issue too. Their (temporary?) solution was to > disable FPU exceptions after every instruction iteration? Some solution > is desired for this project. > > > Changelog > ======= > > v1 -> v2: > - Moved -O0 to ifdef DEBUG > - Building with ASAN by default > - Removed a number of macros from emulator_ops.c and moved them as > static inline functions in emulator_ops.h > - Accidentally changed the example in simple-harness (reverted in v3) > - Introduced patch 4 for scripts > > v2 -> v3: > - Removed a workaround for printf smashing the stack when compiled > with -mcmodel=kernel, and stopped compiling with -mcmodel=kernel > - Added a null check for malloc's return value > - Moved more macros from emulator_ops.c into emulator_ops.h as > static inline functions > - Removed commented out code > - Moved changes to emulator_ops.h into the first patch > - Moved addition of afl-many script to the script patch > - Fixed spelling mistakes in documentation > - Reverted the simple-harness example back to the more useful original one > - Moved non-essential development scripts from patch 4 to new patch 5 > > v3 -> v4: > - Stubbed out all unimplemented emulator_ops with a unimplemented_op macro > - Setting FAIL_ON_UNIMPLEMENTED_OP on compile decides whether calling these > is treated as a crash or ignored > - Moved setting up core dumps out of the default build/install path and > detailed this change in the README > - Added a .sh extention to afl-many > - Added an optional timeout to afl-many.sh and made deploy_remote.sh use it > - Building no longer creates a new .config each time and does not force any > config options > - Fixed a path bug in afl-many.sh > > Any comments/suggestions are greatly appreciated. > > Best, > Sam Caccavale > > Sam Caccavale (5): > Build target for emulate.o as a userspace binary > Emulate simple x86 instructions in userspace > Demonstrating unit testing via simple-harness > Added build and install scripts > Development scripts for crash triage and deploy > > tools/Makefile | 9 + > tools/fuzz/x86ie/.gitignore | 2 + > tools/fuzz/x86ie/Makefile | 54 ++ > tools/fuzz/x86ie/README.md | 21 + > tools/fuzz/x86ie/afl-harness.c | 151 +++++ > tools/fuzz/x86ie/common.h | 87 +++ > tools/fuzz/x86ie/emulator_ops.c | 590 ++++++++++++++++++ > tools/fuzz/x86ie/emulator_ops.h | 134 ++++ > tools/fuzz/x86ie/scripts/afl-many.sh | 31 + > tools/fuzz/x86ie/scripts/bin.sh | 49 ++ > tools/fuzz/x86ie/scripts/build.sh | 34 + > tools/fuzz/x86ie/scripts/coalesce.sh | 5 + > tools/fuzz/x86ie/scripts/deploy.sh | 9 + > tools/fuzz/x86ie/scripts/deploy_remote.sh | 10 + > tools/fuzz/x86ie/scripts/gen_output.sh | 11 + > tools/fuzz/x86ie/scripts/install_afl.sh | 15 + > .../fuzz/x86ie/scripts/install_deps_ubuntu.sh | 5 + > tools/fuzz/x86ie/scripts/rebuild.sh | 6 + > tools/fuzz/x86ie/scripts/run.sh | 10 + > tools/fuzz/x86ie/scripts/summarize.sh | 9 + > tools/fuzz/x86ie/simple-harness.c | 49 ++ > tools/fuzz/x86ie/stubs.c | 59 ++ > tools/fuzz/x86ie/stubs.h | 52 ++ Sorry I didn't realize it before. Isn't that missing a patch to the MAINTAINERS file? Alex