Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worse scenario, could lead to heap overflows.

Link: https://github.com/KSPP/linux/issues/160
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/gpu/drm/nouveau/nouveau_svm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index 266809e511e2..46a5a1016e37 100644
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -925,8 +925,8 @@ nouveau_pfns_map(struct nouveau_svmm *svmm, struct mm_struct *mm,
 
 	mutex_lock(&svmm->mutex);
 
-	ret = nvif_object_ioctl(&svmm->vmm->vmm.object, args, sizeof(*args) +
-				npages * sizeof(args->p.phys[0]), NULL);
+	ret = nvif_object_ioctl(&svmm->vmm->vmm.object, args,
+				struct_size(args, p.phys, npages), NULL);
 
 	mutex_unlock(&svmm->mutex);
 }
-- 
2.27.0

Reviewed-by: Lyude Paul <lyude@redhat.com>

Will push this to drm-misc-next, thanks!

On Mon, 2022-02-07 at 17:39 -0600, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worse scenario, could lead to heap overflows.
> 
> Link: https://github.com/KSPP/linux/issues/160
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/gpu/drm/nouveau/nouveau_svm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c
> b/drivers/gpu/drm/nouveau/nouveau_svm.c
> index 266809e511e2..46a5a1016e37 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_svm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
> @@ -925,8 +925,8 @@ nouveau_pfns_map(struct nouveau_svmm *svmm, struct
> mm_struct *mm,
>  
>         mutex_lock(&svmm->mutex);
>  
> -       ret = nvif_object_ioctl(&svmm->vmm->vmm.object, args, sizeof(*args)
> +
> -                               npages * sizeof(args->p.phys[0]), NULL);
> +       ret = nvif_object_ioctl(&svmm->vmm->vmm.object, args,
> +                               struct_size(args, p.phys, npages), NULL);
>  
>         mutex_unlock(&svmm->mutex);
>  }

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat