Backport PR #2421: Cannot run Jupyter lab subcommands from root

notebook/notebookapp.py

@@ -339,6 +339,11 @@ def start(self):
     """
 )
 
+flags['allow-root']=(
+    {'NotebookApp' : {'allow_root' : True}},
+    "Allow the notebook to be run from root user."
+)
+
 # Add notebook manager flags
 flags.update(boolean_flag('script', 'FileContentsManager.save_script',
                'DEPRECATED, IGNORED',
@@ -438,6 +443,10 @@ def _log_format_default(self):
         help="Set the Access-Control-Allow-Credentials: true header"
     )
 
+    allow_root = Bool(False, config=True, 
+        help="Whether to allow the user to run the notebook as root."
+    )
+
     default_url = Unicode('/tree', config=True,
         help="The default URL to redirect to from `/`"
     )
@@ -1194,8 +1203,19 @@ def start(self):
         
         This method takes no arguments so all configuration and initialization
         must be done prior to calling this method."""
+
         super(NotebookApp, self).start()
 
+        if not self.allow_root:
+            # check if we are running as root, and abort if it's not allowed
+            try:
+                uid = os.geteuid()
+            except AttributeError:
+                uid = -1 # anything nonzero here, since we can't check UID assume non-root
+            if uid == 0:
+                self.log.critical("Running as root is not recommended. Use --allow-root to bypass.")
+                self.exit(1)
+
         info = self.log.info
         for line in self.notebook_info().split("\n"):
             info(line)