[PATCH] drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free()

[PATCH] drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free()

[Roberto Sassu]

If virtio_gpu_object_shmem_init() fails (e.g. due to fault injection, as it
happened in the bug report by syzbot), virtio_gpu_array_put_free() could be
called with objs equal to NULL.

Ensure that objs is not NULL in virtio_gpu_array_put_free(), or otherwise
return from the function.

Cc: stable@vger.kernel.org # 5.13.x
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reported-by: syzbot+e9072e90624a31dfa85f@syzkaller.appspotmail.com
Fixes: 377f8331d0565 ("drm/virtio: fix possible leak/unlock virtio_gpu_object_array")
---
 drivers/gpu/drm/virtio/virtgpu_gem.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
index 2de61b63ef91..48d3c9955f0d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_gem.c
+++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
@@ -248,6 +248,9 @@ void virtio_gpu_array_put_free(struct virtio_gpu_object_array *objs)
 {
 	u32 i;
 
+	if (!objs)
+		return;
+
 	for (i = 0; i < objs->nents; i++)
 		drm_gem_object_put(objs->objs[i]);
 	virtio_gpu_array_free(objs);
-- 
2.32.0

RE: [PATCH] drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free()

[Roberto Sassu]

> From: Roberto Sassu
> Sent: Monday, December 13, 2021 7:31 PM
> If virtio_gpu_object_shmem_init() fails (e.g. due to fault injection, as it
> happened in the bug report by syzbot), virtio_gpu_array_put_free() could be
> called with objs equal to NULL.
> 
> Ensure that objs is not NULL in virtio_gpu_array_put_free(), or otherwise
> return from the function.

Hello

did you have the chance to look at this patch?

Thanks

Roberto

HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063
Managing Director: Li Peng, Zhong Ronghua

> Cc: stable@vger.kernel.org # 5.13.x
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> Reported-by: syzbot+e9072e90624a31dfa85f@syzkaller.appspotmail.com
> Fixes: 377f8331d0565 ("drm/virtio: fix possible leak/unlock
> virtio_gpu_object_array")
> ---
>  drivers/gpu/drm/virtio/virtgpu_gem.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c
> b/drivers/gpu/drm/virtio/virtgpu_gem.c
> index 2de61b63ef91..48d3c9955f0d 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
> @@ -248,6 +248,9 @@ void virtio_gpu_array_put_free(struct
> virtio_gpu_object_array *objs)
>  {
>  	u32 i;
> 
> +	if (!objs)
> +		return;
> +
>  	for (i = 0; i < objs->nents; i++)
>  		drm_gem_object_put(objs->objs[i]);
>  	virtio_gpu_array_free(objs);
> --
> 2.32.0

Re: [PATCH] drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free()

[Gerd Hoffmann]

On Mon, Dec 13, 2021 at 07:31:22PM +0100, Roberto Sassu wrote:
> If virtio_gpu_object_shmem_init() fails (e.g. due to fault injection, as it
> happened in the bug report by syzbot), virtio_gpu_array_put_free() could be
> called with objs equal to NULL.
> 
> Ensure that objs is not NULL in virtio_gpu_array_put_free(), or otherwise
> return from the function.
> 
> Cc: stable@vger.kernel.org # 5.13.x
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> Reported-by: syzbot+e9072e90624a31dfa85f@syzkaller.appspotmail.com
> Fixes: 377f8331d0565 ("drm/virtio: fix possible leak/unlock virtio_gpu_object_array")

Pushed to drm-misc-next.

thanks,
  Gerd