[Intel-gfx] [PATCH v5 5/6] drm/i915: add query uAPI

[Lionel Landwerlin]

On 16/01/18 14:08, Chris Wilson wrote:
> Quoting Lionel Landwerlin (2018-01-16 13:40:09)
>> +int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
>> +{
>> +       struct drm_i915_query *args = data;
>> +       struct drm_i915_query_item __user *user_item_ptr =
>> +               u64_to_user_ptr(args->items_ptr);
>> +       u32 i;
> You need to reject non-zero pad values. I would just rename them as
> flags because that's almost always the first field added later on when
> extending the ioctl.

Ah yeah, forgot about that...

>
>> +
>> +       for (i = 0; i < args->num_items; i++, user_item_ptr++) {
>> +               struct drm_i915_query_item item;
>> +
>> +               if (copy_from_user(&item, user_item_ptr, sizeof(item)))
>> +                       return -EFAULT;
>> +
>> +               switch (item.query_id) {
>> +               default:
>> +                       return -EINVAL;
>> +               }
>> +
>> +               if (copy_to_user(user_item_ptr, &item, sizeof(item)))
>> +                       return -EFAULT;
> I would suggest not doing a blind copy of the entire item. The majority
> of it should be unchanged, but copying everything sounds like an easy
> accident to leak information (looking at that item_ptr.ptr!). The only
> out-param in the item is the length, so just copy that back?
> -Chris
>
Done.