2022-03-28 20:45:23

by Xiaomeng Tong

Subject: [PATCH] virtio-gpu: fix a missing check to avoid NULL dereference

'cache_ent' could be set NULL inside virtio_gpu_cmd_get_capset()
and it will lead to a NULL dereference by a lately use of it
(i.e., ptr = cache_ent->caps_cache). Fix it with a NULL check.

Fixes: 62fb7a5e10962 ("virtio-gpu: add 3d/virgl support")
Signed-off-by: Xiaomeng Tong <[email protected]>
---
drivers/gpu/drm/virtio/virtgpu_ioctl.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index c708bab555c6..b0f1c4d8fd23 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -579,8 +579,10 @@ static int virtio_gpu_get_caps_ioctl(struct drm_device *dev,
spin_unlock(&vgdev->display_info_lock);

/* not in cache - need to talk to hw */
- virtio_gpu_cmd_get_capset(vgdev, found_valid, args->cap_set_ver,
+ ret = virtio_gpu_cmd_get_capset(vgdev, found_valid, args->cap_set_ver,
&cache_ent);
+ if (ret)
+ return ret;
virtio_gpu_notify(vgdev);

copy_exit:

base-commit: f443e374ae131c168a065ea1748feac6b2e76613
--
2.17.1

2022-03-28 22:55:16

by Chia-I Wu

Subject: Re: [PATCH] virtio-gpu: fix a missing check to avoid NULL dereference

On Sat, Mar 26, 2022 at 10:09 PM Xiaomeng Tong <[email protected]> wrote:
>
> 'cache_ent' could be set NULL inside virtio_gpu_cmd_get_capset()
> and it will lead to a NULL dereference by a lately use of it
> (i.e., ptr = cache_ent->caps_cache). Fix it with a NULL check.
>
> Fixes: 62fb7a5e10962 ("virtio-gpu: add 3d/virgl support")
> Signed-off-by: Xiaomeng Tong <[email protected]>
Reviewed-by: Chia-I Wu <[email protected]>
> ---
> drivers/gpu/drm/virtio/virtgpu_ioctl.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index c708bab555c6..b0f1c4d8fd23 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -579,8 +579,10 @@ static int virtio_gpu_get_caps_ioctl(struct drm_device *dev,
> spin_unlock(&vgdev->display_info_lock);
>
> /* not in cache - need to talk to hw */
> - virtio_gpu_cmd_get_capset(vgdev, found_valid, args->cap_set_ver,
> + ret = virtio_gpu_cmd_get_capset(vgdev, found_valid, args->cap_set_ver,
> &cache_ent);
> + if (ret)
> + return ret;
> virtio_gpu_notify(vgdev);
>
> copy_exit:
>
> base-commit: f443e374ae131c168a065ea1748feac6b2e76613
> --
> 2.17.1
>