From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933095AbdKBNn3 convert rfc822-to-8bit (ORCPT ); Thu, 2 Nov 2017 09:43:29 -0400 Received: from mga06.intel.com ([134.134.136.31]:17684 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932583AbdKBNn2 (ORCPT ); Thu, 2 Nov 2017 09:43:28 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,334,1505804400"; d="scan'208";a="168396797" From: "Roberts, William C" To: "Tobin C. Harding" , Sergey Senozhatsky CC: Sergey Senozhatsky , "kernel-hardening@lists.openwall.com" , "Jason A. Donenfeld" , "Theodore Ts'o" , "Linus Torvalds" , Kees Cook , Paolo Bonzini , Tycho Andersen , "Tejun Heo" , Jordan Glover , Greg KH , Petr Mladek , Joe Perches , Ian Campbell , Catalin Marinas , Will Deacon , Steven Rostedt , Chris Fries , Dave Weinstein , Daniel Micay , Djalal Harouni , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH V8 0/2] printk: hash addresses printed with %p Thread-Topic: [PATCH V8 0/2] printk: hash addresses printed with %p Thread-Index: AQHTU7P5e/Ie6sojY0GHqaAmC4u9tqMBVMWA///EyXA= Date: Thu, 2 Nov 2017 13:43:24 +0000 Message-ID: <476DC76E7D1DF2438D32BFADF679FC563F4B8075@ORSMSX115.amr.corp.intel.com> References: <1508986436-31966-1-git-send-email-me@tobin.cc> <20171027133301.GA612@tigerII.localdomain> <20171031233533.GD3585@eros> <20171102082344.GC655@jagdpanzerIV> <20171102101449.GG7499@eros> In-Reply-To: <20171102101449.GG7499@eros> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.0.0.116 dlp-reaction: no-action x-originating-ip: [10.22.254.139] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Tobin C. Harding [mailto:me@tobin.cc] > Sent: Thursday, November 2, 2017 3:15 AM > To: Sergey Senozhatsky > Cc: Sergey Senozhatsky ; kernel- > hardening@lists.openwall.com; Jason A. Donenfeld ; > Theodore Ts'o ; Linus Torvalds foundation.org>; Kees Cook ; Paolo Bonzini > ; Tycho Andersen ; Roberts, > William C ; Tejun Heo ; Jordan > Glover ; Greg KH > ; Petr Mladek ; Joe > Perches ; Ian Campbell ; Catalin Marinas > ; Will Deacon ; Steven > Rostedt ; Chris Fries ; Dave > Weinstein ; Daniel Micay ; Djalal > Harouni ; linux-kernel@vger.kernel.org > Subject: Re: [PATCH V8 0/2] printk: hash addresses printed with %p > > On Thu, Nov 02, 2017 at 05:23:44PM +0900, Sergey Senozhatsky wrote: > > On (11/01/17 10:35), Tobin C. Harding wrote: > > [..] > > > Yes. The question has been raised will we be here again in 6 years > > > time trying to fix all the uses of %x. And there are already 29K > > > uses of %[xX] in tree, which of these are leaking addresses? This is why Linus' > > > has commented that really effort should be directed at finding the > > > leaks as they happen (in procfs, sysfs, dmesg) instead of fixing > > > this in the code. > > > > got it. thanks. > > > > > So far I haven't been able to come up with any meaningful way to do > > > this on 32 bit machines. There is a patch adding a script to catch > > > leaks on 64 bit machines in flight. > > > > who is expected to run that script? > > If one person runs it and finds one leaking address, I'd say it wast worth writing. If > a bunch of people with different set ups run it and we find a bunch of leaking > addresses, WIN! I wonder if the 0 day testing robot could run it.... > > Your comment did give me the idea of adding some output to the command > offering an email address to send suspicious output for those who do not wish to > investigate it further. I can put my email address if there is not a better option. > > > BTW, can BPF/eBPF printk addresses? > > I know absolutely zero about BPF/eBPF. I guess now is a good time to learn. > > > > This patch needs to be a small part of a continued effort to stop > > > the leaks if we want to have any hope of stopping them. > > > > > > If you have any suggestions on dealing with %x please do say. We > > > have code changes, compiler warnings, and checkpatch - none of which > > > immediately seem great. > > > > hm... just a huge pile of if's > > > > if (is_vmalloc_addr(addr)) > > do_hashing(addr); > > else if (__module_address(addr)) > > do_hashing(addr); > > else if (is_kernel(addr) || is_kernel_inittext(addr)) > > ... > > > > but that's going to be really messy and "iffy". > > This is the only suggestion we have so far. > > thanks, > Tobin.