2021-12-13 18:32:02

by Roberto Sassu

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

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: [email protected] # 5.13.x
Signed-off-by: Roberto Sassu <[email protected]>
Reported-by: [email protected]
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

2021-12-16 15:12:40

by Roberto Sassu

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

> 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: [email protected] # 5.13.x
> Signed-off-by: Roberto Sassu <[email protected]>
> Reported-by: [email protected]
> 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

2022-01-19 19:52:14

by Gerd Hoffmann

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

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: [email protected] # 5.13.x
> Signed-off-by: Roberto Sassu <[email protected]>
> Reported-by: [email protected]
> Fixes: 377f8331d0565 ("drm/virtio: fix possible leak/unlock virtio_gpu_object_array")

Pushed to drm-misc-next.

thanks,
Gerd