Re: [PATCH v2] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc
From: Masami Hiramatsu
Date: Tue Aug 01 2017 - 04:36:02 EST
On Tue, 1 Aug 2017 10:09:09 +0200
Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> On Mon, Jul 31, 2017 at 3:57 AM, Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
> > Check user-given gpio number and reject it before
> > calling gpio_to_desc() because gpio_to_desc() is
> > for kernel driver and it expects given gpio number
> > is valid (means 0 to 511).
> > If given number is invalid, gpio_to_desc() calls
> > WARN() and dump registers and stack for debug.
> > This means user can easily kick WARN() just by
> > writing invalid gpio number (e.g. 512) to
> > /sys/class/gpio/export.
> > Fixes: 0e9a5edf5d01 ("gpio: fix deferred probe detection for legacy API")
> > Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > ---
> > Changes in v2:
> > - Add gpio_to_valid_desc() according to Andy's comment (Thanks!).
> > - Fix patch description.
> I hate the old sysfs ABI sigh. Thanks for fixing it anyways!
> Should this be tagged for stable?
Yes, I think so. Since this has been introduced 3 years ago,
it would be nice to go to older stable trees too.
> Waiting for Andy's review before applying.
> Linus Walleij
Masami Hiramatsu <mhiramat@xxxxxxxxxx>