Re: [patch] [media] media: info leak in media_device_enum_entities()

[Dan Carpenter <dan.carpenter@oracle.com>]

On Sun, Apr 21, 2013 at 01:51:56PM +0200, walter harms wrote:
> 
> 
> Am 21.04.2013 13:10, schrieb Dan Carpenter:
> > The last part of the "u_ent.name" buffer isn't cleared so it still has
> > uninitialized stack memory.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > 
> > diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> > index 99b80b6..1957c0d 100644
> > --- a/drivers/media/media-device.c
> > +++ b/drivers/media/media-device.c
> > @@ -102,9 +102,12 @@ static long media_device_enum_entities(struct media_device *mdev,
> >  		return -EINVAL;
> >  
> >  	u_ent.id = ent->id;
> > -	u_ent.name[0] = '\0';
> > -	if (ent->name)
> > -		strlcpy(u_ent.name, ent->name, sizeof(u_ent.name));
> > +	if (ent->name) {
> > +		strncpy(u_ent.name, ent->name, sizeof(u_ent.name));
> > +		u_ent.name[sizeof(u_ent.name) - 1] = '\0';
> > +	} else {
> > +		memset(u_ent.name, 0, sizeof(u_ent.name));
> > +	}
> 
> I would always memset()
> and then do strncpy() for sizeof(u_ent.name) - 1
> the rest is always zero.

Both ways are fine.  You'd still have to test for "if (ent->name)",
of course.  This way is a little faster because I do the test first.

Mauro, if you want I can redo it?

regards,
dan carpenter