vhost-user-gpu: fix resource leak in 'vg_resource_create_2d' (CVE-2021-3544)

Call 'vugbm_buffer_destroy' in error path to avoid resource leak.

Fixes: CVE-2021-3544
Reported-by: Li Qiang <liq3ea@163.com>
Reviewed-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Li Qiang <liq3ea@163.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20210516030403.107723-3-liq3ea@163.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

contrib/vhost-user-gpu/vhost-user-gpu.c

@@ -349,6 +349,7 @@ vg_resource_create_2d(VuGpu *g,
         g_critical("%s: resource creation failed %d %d %d",
                    __func__, c2d.resource_id, c2d.width, c2d.height);
         g_free(res);
+        vugbm_buffer_destroy(&res->buffer);
         cmd->error = VIRTIO_GPU_RESP_ERR_OUT_OF_MEMORY;
         return;
     }