From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965152AbcALKxe (ORCPT ); Tue, 12 Jan 2016 05:53:34 -0500 Received: from mail-wm0-f50.google.com ([74.125.82.50]:32836 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965131AbcALKxY (ORCPT ); Tue, 12 Jan 2016 05:53:24 -0500 Date: Tue, 12 Jan 2016 10:53:19 +0000 From: Lee Jones To: Bjorn Andersson Cc: Arnd Bergmann , "linux-arm-kernel@lists.infradead.org" , Ohad Ben-Cohen , "devicetree@vger.kernel.org" , Florian Fainelli , kernel@stlinux.com, Nathan Lynch , "linux-kernel@vger.kernel.org" , ludovic.barre@st.com, Maxime Coquelin Subject: Re: [RESEND v4 2/6] remoteproc: debugfs: Add ability to boot remote processor using debugfs Message-ID: <20160112105319.GB27358@x1> References: <1448370862-19120-1-git-send-email-lee.jones@linaro.org> <2600153.9u9Z7N2IT1@wuerfel> <20151203172830.GB26902@x1> <2473673.tSymyNlg3h@wuerfel> <20151204082427.GC26902@x1> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 28 Dec 2015, Bjorn Andersson wrote: > On Fri, Dec 4, 2015 at 12:24 AM, Lee Jones wrote: > > On Thu, 03 Dec 2015, Arnd Bergmann wrote: > > > >> On Thursday 03 December 2015 17:28:30 Lee Jones wrote: > >> > > > >> > > Ah, interesting. I haven't tried myself, and just tried to read the > >> > > code. Maybe glibc already catches zero-length writes before it gets > >> > > into the kernel, or I just missed the part of the syscall that checks > >> > > for this. > >> > > >> > Glibc is responsible indeed: > >> > > >> > http://osxr.org/glibc/source/io/write.c > >> > >> Ok, so an attacker can force the stack overflow by calling > >> syscall(__NR_write, fd, p, 0) if that has any potential value, > >> but normal users won't hit this case. > > > > Right. I have fixed the issue (and another one I found) anyway, if > > only to rid the GCC warning. > > > > Sorry, but I'm unable to find a new version of this patch, did I miss > it or could you resend it? I didn't send it out. Just looking at this again, post-vacation. > Also, as I looked at this again, we should probably return an error if > count >= sizeof(buf) rather than just acknowledging the input (same in > the other debugfs write function in this file). Sure. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog