Re: [patch] mfd: vexpress: use after free in vexpress_syscfg_regmap_init()

Dan Carpenter
2014-06-11T10:07:52Z

On Wed, Jun 11, 2014 at 10:22:22AM +0100, Pawel Moll wrote:
> On Wed, 2014-06-11 at 07:07 +0100, Dan Carpenter wrote:
> > We should return NULL if regmap_init() fails instead of continuing.
> >
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> >
> > diff --git a/drivers/misc/vexpress-syscfg.c b/drivers/misc/vexpress-syscfg.c
> > index 73068e5..2c0ddb2 100644
> > --- a/drivers/misc/vexpress-syscfg.c
> > +++ b/drivers/misc/vexpress-syscfg.c
> > @@ -231,10 +231,12 @@ static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
> > func->regmap = regmap_init(dev, NULL, func,
> > &vexpress_syscfg_regmap_config);
> >
> > - if (IS_ERR(func->regmap))
> > + if (IS_ERR(func->regmap)) {
> > kfree(func);
> > - else
> > - list_add(&func->list, &syscfg->funcs);
> > + return NULL;
> > + }
> > +
> > + list_add(&func->list, &syscfg->funcs);
> >
> > return func->regmap;
> > }
>
> Not really, no. What made you think so?
>
> vexpress_config_bridge_ops.regmap_init should return an ERR_PTR in case
> of troubles, not a NULL. See devm_regmap_init_vexpress_config() in
> drivers/bus/vexpress-config.c:
>
> regmap = bridge->ops->regmap_init(dev, bridge->context);
> if (IS_ERR(regmap)) {

Ah... That was sloppy of me. There is a similar bug earlier and I'll
fix that as well.

regards,
dan carpenter