Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965300AbbEMNvO (ORCPT ); Wed, 13 May 2015 09:51:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39011 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933065AbbEMNvL (ORCPT ); Wed, 13 May 2015 09:51:11 -0400 Date: Wed, 13 May 2015 08:51:09 -0500 From: Josh Poimboeuf To: Michal Marek Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Peter Zijlstra , x86@kernel.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/3] x86, stackvalidate: Compile-time stack frame pointer validation Message-ID: <20150513135109.GA28284@treble.redhat.com> References: <555329D2.8090909@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <555329D2.8090909@suse.cz> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2929 Lines: 74 On Wed, May 13, 2015 at 12:39:14PM +0200, Michal Marek wrote: > On 2015-05-11 18:38, Josh Poimboeuf wrote: > > Frame pointer based stack traces aren't always reliable. One big reason > > is that most asm functions don't set up the frame pointer. > > > > Fix that by enforcing that all asm functions honor CONFIG_FRAME_POINTER. > > This is done with a new stackvalidate host tool which is automatically > > run for every compiled .S file and which validates that every asm > > function does the proper frame pointer setup. > > > > Also, to make sure somebody didn't forget to annotate their callable asm code > > as a function, flag an error for any return instructions which are hiding > > outside of a function. In almost all cases, return instructions are part of > > callable functions and should be annotated as such so that we can validate > > their frame pointer usage. A whitelist mechanism exists for those few return > > instructions which are not actually in callable code. > > > > It currently only supports x86_64. It *almost* supports x86_32, but the > > stackvalidate code doesn't yet know how to deal with 32-bit REL > > relocations for the return whitelists. I tried to make the code generic > > so that support for other architectures can be plugged in pretty easily. > > > > As a first step, all reported non-compliances result in warnings. Right > > now I'm seeing 200+ warnings. Once we get them all cleaned up, we can > > change the warnings to build errors so the asm code can stay clean. > > > > Signed-off-by: Josh Poimboeuf > > --- > > MAINTAINERS | 6 + > > arch/Kconfig | 4 + > > arch/x86/Kconfig | 1 + > > arch/x86/Makefile | 6 +- > > lib/Kconfig.debug | 11 ++ > > scripts/Makefile | 1 + > > scripts/Makefile.build | 22 ++- > > For the kbuild parts: Acked-by: Michal Marek Thanks! > > +int main(int argc, char *argv[]) > > +{ > > + struct args args; > > + struct elf *elf; > > + struct section *sec; > > + int ret, warnings = 0; > > + > > + argp_parse(&argp, argc, argv, 0, 0, &args); > > + > > + elf = elf_open(args.args[0]); > > + if (!elf) { > > + fprintf(stderr, "error reading elf file %s\n", args.args[0]); > > + return 1; > > + } > > + > > + if (is_file_whitelisted(elf)) > > + return 0; > > + > > + list_for_each_entry(sec, &elf->sections, list) { > > + ret = validate_section(elf, sec); > > + if (ret < 0) > > + return -1; > > return 1? Since this is the exit status of the program. Ok, I'll change it to 1. -- Josh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/