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 223cfb0673277680b39c58943cc090fbdd9ea407..1f9e26ebb569a71720e5db60dea7185d82e811c4 100644 (file)
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2203,7 +2203,7 @@ 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);
@@ -2263,7 +2263,7 @@ 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!", vtpminfo->backend);
        goto err;