linux-kernel - Re: [RESEND v4 2/6] remoteproc: debugfs: Add ability to boot remote processor using debugfs

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Date:	Tue, 12 Jan 2016 10:53:19 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Bjorn Andersson <bjorn@...o.se>
Cc:	Arnd Bergmann <arnd@...db.de>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Ohad Ben-Cohen <ohad@...ery.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	Florian Fainelli <f.fainelli@...il.com>, kernel@...inux.com,
	Nathan Lynch <Nathan_Lynch@...tor.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	ludovic.barre@...com, Maxime Coquelin <maxime.coquelin@...com>
Subject: Re: [RESEND v4 2/6] remoteproc: debugfs: Add ability to boot remote
 processor using debugfs

On Mon, 28 Dec 2015, Bjorn Andersson wrote:

> On Fri, Dec 4, 2015 at 12:24 AM, Lee Jones <lee.jones@...aro.org> 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
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