vhost-user-gpu: fix memory leak in vg_resource_attach_backing (CVE-2021-3544)

Git-commit: b9f79858a614d95f5de875d0ca31096eaab72c3b
References: CVE-2021-3544

Check whether the 'res' has already been attach_backing to avoid
memory leak.

Fixes: CVE-2021-3544
Reported-by: Li Qiang <liq3ea@163.com>
virtio-gpu fix: 204f01b309 ("virtio-gpu: fix memory leak
in resource attach backing")

Signed-off-by: Li Qiang <liq3ea@163.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20210516030403.107723-4-liq3ea@163.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Jose R. Ziviani <jziviani@suse.de>

diff --git a/contrib/vhost-user-gpu/main.c b/contrib/vhost-user-gpu/main.c
index 74c97c1585f6bd2e9cef94cde3afb9fc730c5ce1..e728237858d279a32698c0fc0de72bb460fc7815 100644 (file)
--- a/contrib/vhost-user-gpu/main.c
+++ b/contrib/vhost-user-gpu/main.c
@@ -468,6 +468,11 @@ vg_resource_attach_backing(VuGpu *g,
         return;
     }
 
+    if (res->iov) {
+        cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;
+        return;
+    }
+
     ret = vg_create_mapping_iov(g, &ab, cmd, &res->iov);
     if (ret != 0) {
         cmd->error = VIRTIO_GPU_RESP_ERR_UNSPEC;