From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 833F078D for ; Tue, 2 Aug 2016 19:02:22 +0000 (UTC) Received: from mail-it0-f43.google.com (mail-it0-f43.google.com [209.85.214.43]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 5D034A7 for ; Tue, 2 Aug 2016 19:02:21 +0000 (UTC) Received: by mail-it0-f43.google.com with SMTP id j124so212577848ith.1 for ; Tue, 02 Aug 2016 12:02:21 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1469631987.27356.48.camel@HansenPartnership.com> <20150804152622.GY30479@wotan.suse.de> <1468612258.5335.0.camel@linux.vnet.ibm.com> <1468612671.5335.5.camel@linux.vnet.ibm.com> <20160716005213.GL30372@sirena.org.uk> <1469544138.120686.327.camel@infradead.org> <14209.1469636040@warthog.procyon.org.uk> <1469636881.27356.70.camel@HansenPartnership.com> <1469637367.27356.73.camel@HansenPartnership.com> <1469648220.23563.15.camel@linux.vnet.ibm.com> From: Ard Biesheuvel Date: Tue, 2 Aug 2016 21:02:19 +0200 Message-ID: To: Andy Lutomirski Content-Type: text/plain; charset=UTF-8 Cc: James Bottomley , Mark Brown , "ksummit-discuss@lists.linuxfoundation.org" Subject: Re: [Ksummit-discuss] Last minute nominations: mcgrof and toshi List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 2 August 2016 at 20:55, Andy Lutomirski wrote: > On a related topic: last year or so, I argued that > CONFIG_MODULE_SIG_ALL and, more generally, the idea that in-tree > modules should be signed, is a suboptimal design. Instead, I think > that the kernel shoud just learn to recognize its in-tree modules by > hash. This would allow reproducible builds, get rid of the > autogenerated key, and would allow distros that don't support binary > modules to avoid needing the asymmetric key infrastructure at all (for > modules, anyway -- firmware is a different story. But a firmware > signing key doesn't interfere with the kernel build process the way > that an in-tree module signing key does.) > > On the theory that code speaks louder than vitriol, I decided to try > to implement it. The actual code is trivial (I expect under 50 lines > *total* for the compile-time and run-time parts together), but > convincing make to build the thing is a real pain in the arse. > > So expect code from me before KS unless I really get stuck fighting > kbuild. And, unless anyone objects, I intend to propose that we > delete CONFIG_MODULE_SIG_ALL entirely once this thing works. > This is exactly what I implemented for TomTom years ago, and the only issues I remember from the top of my head were: - build order: vmlinux needs to be built after the modules, but currently, building the modules requires vmlinux to be built already - debug symbols: modules are stripped when installing them, and taking the hash needs to be done afterwards Then,c-ize a build time sorted list of hashes, and do a binary search at verification time.