Merge pull request #96 from CanonicalLtd/identity_field_protection

Implement username field protection

subiquity/ui/interactive.py

@@ -18,6 +18,7 @@
 
 from urwid import (Edit, IntEdit, RadioButton, WidgetWrap)
 import logging
+import re
 
 log = logging.getLogger("subiquity.ui.input")
 
@@ -59,6 +60,26 @@ class PasswordEditor(StringEditor):
         super().__init__(caption, mask=mask)
 
 
+class UsernameEditor(StringEditor):
+    """ Username input prompt with input rules
+    """
+
+    def keypress(self, size, key):
+        ''' restrict what chars we allow for username '''
+
+        userlen = len(self.value)
+        if userlen == 0:
+            username = r'[a-z_]'
+        else:
+            username = r'[a-z0-9_-]'
+
+        # don't allow non username chars
+        if re.match(username, key) is None:
+            return False
+
+        return super().keypress(size, key)
+
+
 class IntegerEditor(WidgetWrap):
     """ IntEdit input class
     """

subiquity/ui/views/identity.py

@@ -21,7 +21,9 @@ Welcome provides user with language selection
 import logging
 from urwid import (Pile, Columns, Text, ListBox)
 from subiquity.ui.buttons import done_btn, cancel_btn
-from subiquity.ui.interactive import StringEditor, PasswordEditor
+from subiquity.ui.interactive import (PasswordEditor,
+                                      StringEditor,
+                                      UsernameEditor)
 from subiquity.ui.utils import Padding, Color
 from subiquity.view import ViewPolicy
 
@@ -34,7 +36,7 @@ class IdentityView(ViewPolicy):
         self.signal = signal
         self.items = []
         self.realname = StringEditor(caption="")
-        self.username = StringEditor(caption="")
+        self.username = UsernameEditor(caption="")
         self.password = PasswordEditor(caption="")
         self.error = Text("", align="center")
         self.confirm_password = PasswordEditor(caption="")
@@ -105,6 +107,12 @@ class IdentityView(ViewPolicy):
             self.password.value = ""
             self.confirm_password.value = ""
             return
+
+        if len(self.username.value) > 32:
+            self.error.set_text("Username too long, must be < 32")
+            self.username.value = ""
+            return
+
         cpassword = self.model.encrypt_password(self.password.value)
         log.debug("*crypted* User input: {} {} {}".format(
             self.username.value, cpassword, cpassword))