From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 17 Oct 2017 20:35:16 -0400 From: Steven Rostedt Message-ID: <20171017203516.3746395e@vmware.local.home> In-Reply-To: <20171017231559.GD8001@eros> References: <1508215972-7769-1-git-send-email-me@tobin.cc> <20171017093119.6dd98919@gandalf.local.home> <20171017231559.GD8001@eros> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: [kernel-hardening] Re: [PATCH v2] printk: hash addresses printed with %p To: "Tobin C. Harding" Cc: kernel-hardening@lists.openwall.com, Linus Torvalds , Kees Cook , Paolo Bonzini , Tycho Andersen , "Roberts, William C" , Tejun Heo , Jordan Glover , Greg KH , Petr Mladek , Joe Perches , Ian Campbell , Sergey Senozhatsky , Catalin Marinas , Will Deacon , Chris Fries , Dave Weinstein , Daniel Micay , Djalal Harouni , linux-kernel@vger.kernel.org List-ID: On Wed, 18 Oct 2017 10:15:59 +1100 "Tobin C. Harding" wrote: > > Does %p[FfSs] leak addresses? Well, I guess it does if they are not > > found in kallsyms, but otherwise you have: > > > > function+0x > > You are correct %pF and %pS print an offset. Does this provide an attack vector, > I didn't think so but I'm no security expert. If they do then we need to amend > those calls also. Hopefully not. We changed stack dumps to use them only instead of showing addresses because of the location leak. -- Steve From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758519AbdJRAfZ (ORCPT ); Tue, 17 Oct 2017 20:35:25 -0400 Received: from smtprelay0040.hostedemail.com ([216.40.44.40]:33663 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758388AbdJRAfV (ORCPT ); Tue, 17 Oct 2017 20:35:21 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::::::::::::::::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1538:1593:1594:1711:1714:1730:1747:1777:1792:2393:2553:2559:2562:2894:3138:3139:3140:3141:3142:3351:3622:3865:3866:3867:3868:3870:3872:3873:5007:6261:6742:6743:7875:8957:10004:10400:10848:10967:11232:11658:11914:12663:12740:12760:12895:13069:13311:13357:13439:14181:14659:21080:21627:30025:30054:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:1,LUA_SUMMARY:none X-HE-Tag: tooth72_859892c151920 X-Filterd-Recvd-Size: 2149 Date: Tue, 17 Oct 2017 20:35:16 -0400 From: Steven Rostedt To: "Tobin C. Harding" Cc: kernel-hardening@lists.openwall.com, Linus Torvalds , Kees Cook , Paolo Bonzini , Tycho Andersen , "Roberts, William C" , Tejun Heo , Jordan Glover , Greg KH , Petr Mladek , Joe Perches , Ian Campbell , Sergey Senozhatsky , Catalin Marinas , Will Deacon , Chris Fries , Dave Weinstein , Daniel Micay , Djalal Harouni , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] printk: hash addresses printed with %p Message-ID: <20171017203516.3746395e@vmware.local.home> In-Reply-To: <20171017231559.GD8001@eros> References: <1508215972-7769-1-git-send-email-me@tobin.cc> <20171017093119.6dd98919@gandalf.local.home> <20171017231559.GD8001@eros> X-Mailer: Claws Mail 3.15.1-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 18 Oct 2017 10:15:59 +1100 "Tobin C. Harding" wrote: > > Does %p[FfSs] leak addresses? Well, I guess it does if they are not > > found in kallsyms, but otherwise you have: > > > > function+0x > > You are correct %pF and %pS print an offset. Does this provide an attack vector, > I didn't think so but I'm no security expert. If they do then we need to amend > those calls also. Hopefully not. We changed stack dumps to use them only instead of showing addresses because of the location leak. -- Steve