Re: [RESEND v4 2/6] remoteproc: debugfs: Add ability to boot remote processor using debugfs
From: Bjorn Andersson
Date: Mon Dec 28 2015 - 13:38:13 EST
On Fri, Dec 4, 2015 at 12:24 AM, Lee Jones <lee.jones@xxxxxxxxxx> 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?
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).
Regards,
Bjorn
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