[Xen-changelog] [xen master] libxl: Do not trust backend for vtpm in getinfo (except uuid)

[patchbot@xxxxxxx]

commit 615c2be2ff0788c71bf6520abd79154f15bb5a79
Author:     Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
AuthorDate: Fri Apr 29 17:18:44 2016 +0100
Commit:     Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
CommitDate: Thu Jun 2 15:53:29 2016 +0100

    libxl: Do not trust backend for vtpm in getinfo (except uuid)
    
    * Do not check the backend for existence.  We have already read the
      /libxl path so know that the vtpm exists (or is supposed to); if the
      backend doesn't exist then that must be the backend's doing.
    * Get the frontend path from the /libxl directory.
    * The frontend domid is the guest domid, and does not need to be read
      from xenstore (!)
    
    We still attempt to read the uuid from the backend.  This will be
    fixed in the next patch.
    
    This is part of XSA-178.
    
    Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
    Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/libxl/libxl.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 752dc58..223cfb0 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2241,9 +2241,6 @@ int libxl_device_vtpm_getinfo(libxl_ctx *ctx,
     if (!vtpminfo->backend) {
         goto err;
     }
-    if(!libxl__xs_read(gc, XBT_NULL, vtpminfo->backend)) {
-       goto err;
-    }
 
     rc = libxl__backendpath_parse_domid(gc, vtpminfo->backend,
                                         &vtpminfo->backend_id);
@@ -2262,11 +2259,8 @@ int libxl_device_vtpm_getinfo(libxl_ctx *ctx,
     vtpminfo->rref = val ? strtoul(val, NULL, 10) : -1;
 
     vtpminfo->frontend = xs_read(ctx->xsh, XBT_NULL,
-          GCSPRINTF("%s/frontend", vtpminfo->backend), NULL);
-
-    val = libxl__xs_read(gc, XBT_NULL,
-          GCSPRINTF("%s/frontend-id", vtpminfo->backend));
-    vtpminfo->frontend_id = val ? strtoul(val, NULL, 10) : -1;
+          GCSPRINTF("%s/frontend", libxl_path), NULL);
+    vtpminfo->frontend_id = domid;
 
     val = libxl__xs_read(gc, XBT_NULL,
           GCSPRINTF("%s/uuid", vtpminfo->backend));
--
generated by git-patchbot for /home/xen/git/xen.git#master

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