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path: root/drivers/gpu/drm/virtio/virtgpu_ioctl.c
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Diffstat (limited to 'drivers/gpu/drm/virtio/virtgpu_ioctl.c')
-rw-r--r--drivers/gpu/drm/virtio/virtgpu_ioctl.c24
1 files changed, 18 insertions, 6 deletions
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 5d05093014ac..da45215a933d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -126,7 +126,6 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
void __user *user_bo_handles = NULL;
struct virtio_gpu_object_array *buflist = NULL;
struct sync_file *sync_file;
- int in_fence_fd = exbuf->fence_fd;
int out_fence_fd = -1;
void *buf;
uint64_t fence_ctx;
@@ -152,13 +151,11 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
ring_idx = exbuf->ring_idx;
}
- exbuf->fence_fd = -1;
-
virtio_gpu_create_context(dev, file);
if (exbuf->flags & VIRTGPU_EXECBUF_FENCE_FD_IN) {
struct dma_fence *in_fence;
- in_fence = sync_file_get_fence(in_fence_fd);
+ in_fence = sync_file_get_fence(exbuf->fence_fd);
if (!in_fence)
return -EINVAL;
@@ -358,10 +355,18 @@ static int virtio_gpu_resource_create_ioctl(struct drm_device *dev, void *data,
drm_gem_object_release(obj);
return ret;
}
- drm_gem_object_put(obj);
rc->res_handle = qobj->hw_res_handle; /* similiar to a VM address */
rc->bo_handle = handle;
+
+ /*
+ * The handle owns the reference now. But we must drop our
+ * remaining reference *after* we no longer need to dereference
+ * the obj. Otherwise userspace could guess the handle and
+ * race closing it from another thread.
+ */
+ drm_gem_object_put(obj);
+
return 0;
}
@@ -723,11 +728,18 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
drm_gem_object_release(obj);
return ret;
}
- drm_gem_object_put(obj);
rc_blob->res_handle = bo->hw_res_handle;
rc_blob->bo_handle = handle;
+ /*
+ * The handle owns the reference now. But we must drop our
+ * remaining reference *after* we no longer need to dereference
+ * the obj. Otherwise userspace could guess the handle and
+ * race closing it from another thread.
+ */
+ drm_gem_object_put(obj);
+
return 0;
}