libxl: Do not trust backend in libxl__device_exists

To determine whether a device is supposed to exist, look in /libxl,
rather than the backend.

This is part of XSA-178.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>

diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 4b61b4c2d5a3b916ff90f06909176d326c318020..4717027821a4330a82fad8c17bf629f4d58dc8c0 100644 (file)
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -54,7 +54,7 @@ int libxl__device_exists(libxl__gc *gc, xs_transaction_t t,
                          libxl__device *device)
 {
     int rc;
-    char *be_path = libxl__device_backend_path(gc, device);
+    char *be_path = libxl__device_libxl_path(gc, device);
     const char *dir;
 
     rc = libxl__xs_read_checked(gc, t, be_path, &dir);