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* [PATCH] drm/virtio: add driver_priv validation in virtio_gpu_create_context
@ 2024-03-28 13:43 Maxim Korotkov
  2024-04-11 12:31 ` Dmitry Osipenko
  0 siblings, 1 reply; 2+ messages in thread
From: Maxim Korotkov @ 2024-03-28 13:43 UTC (permalink / raw)
  To: David Airlie
  Cc: Maxim Korotkov, Gerd Hoffmann, Gurchetan Singh, Chia-I Wu,
	Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
	Daniel Vetter, Emil Velikov, Ivan Kapranov, lvc-project,
	dri-devel, virtualization, linux-kernel

The pointer file->driver_priv was dereferenced without checking
against NULL, but in the "virtio_gpu_transfer_to_host_ioctl" function
it was checked against NULL after calling virtio_gpu_create_context
function.

Found by Security Code and Linux Verification Center(linuxtesting.org)
Fixes: 72b48ae800da ("drm/virtio: enqueue virtio_gpu_create_context after the first 3D ioctl")
Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index e4f76f315550..98fe9ad4ed15 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -64,6 +64,9 @@ void virtio_gpu_create_context(struct drm_device *dev, struct drm_file *file)
 	struct virtio_gpu_device *vgdev = dev->dev_private;
 	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
 
+	if (!vfpriv)
+		return;
+
 	mutex_lock(&vfpriv->context_lock);
 	if (vfpriv->context_created)
 		goto out_unlock;
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] drm/virtio: add driver_priv validation in virtio_gpu_create_context
  2024-03-28 13:43 [PATCH] drm/virtio: add driver_priv validation in virtio_gpu_create_context Maxim Korotkov
@ 2024-04-11 12:31 ` Dmitry Osipenko
  0 siblings, 0 replies; 2+ messages in thread
From: Dmitry Osipenko @ 2024-04-11 12:31 UTC (permalink / raw)
  To: Maxim Korotkov, David Airlie
  Cc: Gerd Hoffmann, Gurchetan Singh, Chia-I Wu, Maarten Lankhorst,
	Maxime Ripard, Thomas Zimmermann, Daniel Vetter, Ivan Kapranov,
	lvc-project, dri-devel, virtualization, linux-kernel

On 3/28/24 16:43, Maxim Korotkov wrote:
> The pointer file->driver_priv was dereferenced without checking
> against NULL, but in the "virtio_gpu_transfer_to_host_ioctl" function
> it was checked against NULL after calling virtio_gpu_create_context
> function.
> 
> Found by Security Code and Linux Verification Center(linuxtesting.org)
> Fixes: 72b48ae800da ("drm/virtio: enqueue virtio_gpu_create_context after the first 3D ioctl")
> Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_ioctl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index e4f76f315550..98fe9ad4ed15 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -64,6 +64,9 @@ void virtio_gpu_create_context(struct drm_device *dev, struct drm_file *file)
>  	struct virtio_gpu_device *vgdev = dev->dev_private;
>  	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
>  
> +	if (!vfpriv)
> +		return;
> +
>  	mutex_lock(&vfpriv->context_lock);
>  	if (vfpriv->context_created)
>  		goto out_unlock;

NULL check in virtio_gpu_transfer_to_host_ioctl() is bogus, vfpriv can't
be NULL there.

-- 
Best regards,
Dmitry


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2024-03-28 13:43 [PATCH] drm/virtio: add driver_priv validation in virtio_gpu_create_context Maxim Korotkov
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