libxl: Do not trust backend for vtpm in getinfo (uuid)

Use uuid from /libxl, rather than from backend.  I think the backend
is not supposed to change the uuid, since it seems to be set by libxl
during setup.

If in fact the backend is supposed to be able to change the uuid, this
patch needs to be dropped and replaced by a patch which makes the vtpm
uuid lookup tolerate bad or missing data.

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.c b/tools/libxl/libxl.c
index 1c241cebcc93debab6f074d1ec09fff33f042b27..23ff871b12bd76722b860cce46ffd1c89b7b4a89 100644 (file)
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2200,7 +2200,7 @@ libxl_device_vtpm *libxl_device_vtpm_list(libxl_ctx *ctx, uint32_t domid, int *n
                                               &vtpm->backend_domid);
           if (rc) return NULL;
 
-          tmp = libxl__xs_read(gc, XBT_NULL, GCSPRINTF("%s/uuid", be_path));
+          tmp = libxl__xs_read(gc, XBT_NULL, GCSPRINTF("%s/uuid", libxl_path));
           if (tmp) {
               if(libxl_uuid_from_string(&(vtpm->uuid), tmp)) {
                   LOG(ERROR, "%s/uuid is a malformed uuid?? (%s) Probably a bug!!\n", be_path, tmp);
@@ -2260,7 +2260,7 @@ int libxl_device_vtpm_getinfo(libxl_ctx *ctx,
     vtpminfo->frontend_id = domid;
 
     val = libxl__xs_read(gc, XBT_NULL,
-          GCSPRINTF("%s/uuid", vtpminfo->backend));
+          GCSPRINTF("%s/uuid", libxl_path));
     if(val == NULL) {
        LOG(ERROR, "%s/uuid does not exist!\n", vtpminfo->backend);
        goto err;