Re: [PATCH v2 2/3 drm: Check property/enum name length

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Mar 06, 2018 at 11:22:54AM +0100, Daniel Vetter wrote:
> On Fri, Mar 02, 2018 at 04:03:00PM +0200, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > 
> > Reject requests to add properties/enums with an overly long name.
> > Previously we would have just silently truncated the string and exposed
> > it userspace.
> > 
> > v2: drm_property_create() returns a pointer
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> While you're typing validation code, I noticed that drm_property_add_enum
> allows you to overwrite the name of an existing enum value already added.
> That sounds like something we never want to allow either.

Good point. I suppose we should just WARN and error out there as well?

> 
> Anyway, this is
> 
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> 
> > ---
> >  drivers/gpu/drm/drm_property.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_property.c b/drivers/gpu/drm/drm_property.c
> > index fe8627fb7ae6..c37ac41125b5 100644
> > --- a/drivers/gpu/drm/drm_property.c
> > +++ b/drivers/gpu/drm/drm_property.c
> > @@ -78,6 +78,9 @@ struct drm_property *drm_property_create(struct drm_device *dev, int flags,
> >  	struct drm_property *property = NULL;
> >  	int ret;
> >  
> > +	if (WARN_ON(strlen(name) >= DRM_PROP_NAME_LEN))
> > +		return NULL;
> > +
> >  	property = kzalloc(sizeof(struct drm_property), GFP_KERNEL);
> >  	if (!property)
> >  		return NULL;
> > @@ -372,6 +375,9 @@ int drm_property_add_enum(struct drm_property *property, int index,
> >  {
> >  	struct drm_property_enum *prop_enum;
> >  
> > +	if (WARN_ON(strlen(name) >= DRM_PROP_NAME_LEN))
> > +		return -EINVAL;
> > +
> >  	if (!(drm_property_type_is(property, DRM_MODE_PROP_ENUM) ||
> >  			drm_property_type_is(property, DRM_MODE_PROP_BITMASK)))
> >  		return -EINVAL;
> > -- 
> > 2.16.1
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Ville Syrjälä
Intel OTC
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