Re: [PATCH] drivers: of: check input parameter name for __of_find_property

[Peng Fan <van.freenix@gmail.com>]

Hi Rob,

On Tue, Sep 15, 2015 at 10:56:28AM -0500, Rob Herring wrote:
> On 09/11/2015 08:44 AM, Peng Fan wrote:
> > Check input parameter 'name' for __of_find_property. If name is NULL,
> > of_prop_cmp->strcasecmp may trigger panic.
> 
> Arguably that could be a feature. Do you have a usecase where name being
> NULL is valid and panicking is a problem?

In drivers/pinctrl/devicetree.c

195                 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
196                 prop = of_find_property(np, propname, &size);
197                 kfree(propname);
198                 if (!prop)
199                         break;

If propname is NULL, of_find_property may trigger panic. Anyway propname should be checked
before passing to of_find_property.

I did not met panic message. I wrote this patch when I was reading the piece code.
I think the name parameter should be checked before doing string compare.

Regards,
Peng.

> 
> Rob
> 
> > 
> > Signed-off-by: Peng Fan <van.freenix@gmail.com>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: Frank Rowand <frowand.list@gmail.com>
> > Cc: Grant Likely <grant.likely@linaro.org>
> > ---
> >  drivers/of/base.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/of/base.c b/drivers/of/base.c
> > index 8b5a187..e41436d 100644
> > --- a/drivers/of/base.c
> > +++ b/drivers/of/base.c
> > @@ -215,7 +215,7 @@ static struct property *__of_find_property(const struct device_node *np,
> >  {
> >  	struct property *pp;
> >  
> > -	if (!np)
> > +	if (!np || !name)
> >  		return NULL;
> >  
> >  	for (pp = np->properties; pp; pp = pp->next) {
> > 
>