Re: [PATCH] drm/i915: prevent integer overflow in query_engine_info()

[Andrzej Hajda <andrzej.hajda@xxxxxxxxx>]

On 01.09.2022 17:38, Dan Carpenter wrote:
> This code uses struct_size() but it stores the result in an int so the
> integer overflow checks are not effective.  Record the types as size_t
> to prevent the size from being truncated.
>
> Fixes: bf3c50837506 ("drm/i915/query: Use struct_size() helper")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

Reviewed-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>

Regards
Andrzej
> ---
> I do not know if the integer overflow can happen.  This is a hardenning
> patch just like the conversion to struct_size().
>
>   drivers/gpu/drm/i915/i915_query.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
> index 6ec9c9fb7b0d..43a499fbdc8d 100644
> --- a/drivers/gpu/drm/i915/i915_query.c
> +++ b/drivers/gpu/drm/i915/i915_query.c
> @@ -13,7 +13,7 @@
>   #include <uapi/drm/i915_drm.h>
>   
>   static int copy_query_item(void *query_hdr, size_t query_sz,
> -			   u32 total_length,
> +			   size_t total_length,
>   			   struct drm_i915_query_item *query_item)
>   {
>   	if (query_item->length == 0)
> @@ -135,7 +135,8 @@ query_engine_info(struct drm_i915_private *i915,
>   	struct drm_i915_engine_info info = { };
>   	unsigned int num_uabi_engines = 0;
>   	struct intel_engine_cs *engine;
> -	int len, ret;
> +	size_t len;
> +	int ret;
>   
>   	if (query_item->flags)
>   		return -EINVAL;