Fix root operations on trivfs-translated nodes

* libtrivfs/fsys-getroot.c: When `uids` contain 0, make a verbatim copy of
the real node instead of making an auth-restricted copy.

1 files changed, 14 insertions, 2 deletions

diff --git a/libtrivfs/fsys-getroot.c b/libtrivfs/fsys-getroot.c
index 2bc11f52..c44e5358 100644
--- a/libtrivfs/fsys-getroot.c
+++ b/libtrivfs/fsys-getroot.c
@@ -69,8 +69,20 @@ trivfs_S_fsys_getroot (struct trivfs_control *cntl,
   flags &= O_HURD;
   flags &= ~(O_CREAT|O_EXCL|O_NOLINK|O_NOTRANS);
 
-  err = io_restrict_auth (cntl->underlying,
-			  &new_realnode, uids, nuids, gids, ngids);
+  struct idvec idvec = {
+    .ids = uids,
+    .num = nuids,
+    .alloced = nuids,
+  };
+
+  if (idvec_contains (&idvec, 0))
+    /* Root should be given all our rights.  */
+    err = io_duplicate (cntl->underlying, &new_realnode);
+  else
+    /* Non-root, restrict rights.  */
+    err = io_restrict_auth (cntl->underlying,
+			    &new_realnode, uids, nuids, gids, ngids);
+
   if (err)
     return err;