--- a/nemo-share/src/install-samba	2019-02-08 16:11:14.000000000 +0600
+++ b/nemo-share/src/install-samba	2019-04-29 09:16:24.571726203 +0600
@@ -42,6 +42,15 @@
         uid = int(uid)
         passwd = pwd.getpwuid(uid)
         user = passwd[0]
+    # prefer using the uid provided by pkexec to the command line argument. if
+    # a user authenticated via pkexec then he should only be able to add
+    # himself to the group.
+    uid = os.getenv("PKEXEC_UID", None)
+
+    if uid != None:
+        uid = int(uid)
+         passwd = pwd.getpwuid(uid)
+         user = passwd[0]
     elif len(sys.argv) == 2:
         user = sys.argv[1]
     else: