[PATCH v2] drm/nouveau: fix null pointer dereference in nouveau_connector_get_modes

[PATCH v2] drm/nouveau: fix null pointer dereference in nouveau_connector_get_modes

[Ma Ke]

In nouveau_connector_get_modes(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a possible NULL pointer
dereference on failure of drm_mode_duplicate(). Add a check to avoid npd.

Fixes: 6ee738610f41 ("drm/nouveau: Add DRM driver for NVIDIA GPUs")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
Changes in v2:
- modified the patch according to suggestions.
---
 drivers/gpu/drm/nouveau/nouveau_connector.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index 856b3ef5edb8..0c71d761d378 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -1001,6 +1001,9 @@ nouveau_connector_get_modes(struct drm_connector *connector)
 		struct drm_display_mode *mode;
 
 		mode = drm_mode_duplicate(dev, nv_connector->native_mode);
+		if (!mode)
+			return 0;
+
 		drm_mode_probed_add(connector, mode);
 		ret = 1;
 	}
-- 
2.25.1

Re: [PATCH v2] drm/nouveau: fix null pointer dereference in nouveau_connector_get_modes

[Lyude Paul]

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

Will push this upstream in just a moment, thanks!

On Thu, 2024-06-27 at 10:27 +0800, Ma Ke wrote:
> In nouveau_connector_get_modes(), the return value of
> drm_mode_duplicate()
> is assigned to mode, which will lead to a possible NULL pointer
> dereference on failure of drm_mode_duplicate(). Add a check to avoid
> npd.
> 
> Fixes: 6ee738610f41 ("drm/nouveau: Add DRM driver for NVIDIA GPUs")
> Signed-off-by: Ma Ke <make24@iscas.ac.cn>
> ---
> Changes in v2:
> - modified the patch according to suggestions.
> ---
>  drivers/gpu/drm/nouveau/nouveau_connector.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c
> b/drivers/gpu/drm/nouveau/nouveau_connector.c
> index 856b3ef5edb8..0c71d761d378 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_connector.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
> @@ -1001,6 +1001,9 @@ nouveau_connector_get_modes(struct
> drm_connector *connector)
>  		struct drm_display_mode *mode;
>  
>  		mode = drm_mode_duplicate(dev, nv_connector-
> >native_mode);
> +		if (!mode)
> +			return 0;
> +
>  		drm_mode_probed_add(connector, mode);
>  		ret = 1;
>  	}

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