linux-kernel - Re: [PATCH] platform/x86: huawei-wmi: make validation stricter in huawei_wmi_battery

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Date:   Tue, 15 Oct 2019 15:46:23 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Ayman Bagabas <ayman.bagabas@...il.com>
Cc:     Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Takashi Iwai <tiwai@...e.de>, Mattias Jacobsson <2pi@....nu>,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] platform/x86: huawei-wmi: make validation stricter in
 huawei_wmi_battery_set()

On Tue, Oct 15, 2019 at 08:21:59AM -0400, Ayman Bagabas wrote:
> Hi Dan
> 
> On Tue, Oct 15, 2019, 4:39 AM Dan Carpenter <dan.carpenter@...cle.com>
> wrote:
> 
> > I don't think it makes sense for "end" to be negative or for even for it
> > to be less than "start".  That also means that "start" can't be more
> > than 100 which is good.
> >
> 
> While this makes sense, you run into issues where you cannot set "start"
> before "end" and vice versa.
> 
> Take this scenario, you have start=70 and end=90, now you want to set these
> to start=40 and end=60, you would have to set "start" first before you can
> change the value of "end" otherwise you will run into EINVAL. Now imagine
> you wanna go the opposite direction, you would have to set "end" before you
> can change "start".
> I think having a little wiggle room is fine for such scenarios.
> 

I haven't tested this code...  What you're describing sounds really
very weird to me, but I will accept that you know more about your
use cases than I do.

My other concern is that right now you can set start > 100 or end < 0.

regards,
dan carpenter