If 'virgl_cmd_get_capset' set 'max_size' to 0, the 'virgl_renderer_fill_caps' will write the data after the 'resp'. This patch avoid this by checking the returned 'max_size'.
virtio-gpu fix: abd7f08b23 ("display: virtio-gpu-3d: check virgl capabilities max_size") Fixes: CVE-2021-3546 Reported-by: Li Qiang <liq...@163.com> Reviewed-by: Prasad J Pandit <p...@fedoraproject.org> Signed-off-by: Li Qiang <liq...@163.com> --- contrib/vhost-user-gpu/virgl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/contrib/vhost-user-gpu/virgl.c b/contrib/vhost-user-gpu/virgl.c index a16a311d80..7172104b19 100644 --- a/contrib/vhost-user-gpu/virgl.c +++ b/contrib/vhost-user-gpu/virgl.c @@ -177,6 +177,10 @@ virgl_cmd_get_capset(VuGpu *g, virgl_renderer_get_cap_set(gc.capset_id, &max_ver, &max_size); + if (!max_size) { + cmd->error = VIRTIO_GPU_RESP_ERR_INVALID_PARAMETER; + return; + } resp = g_malloc0(sizeof(*resp) + max_size); resp->hdr.type = VIRTIO_GPU_RESP_OK_CAPSET; -- 2.25.1