Validate matching double quotes in TXT recordsets.

Currently, designate does not validate that if a TXT recordset starts
with a double quote, it also ends with a double quote. So, if user has
provided TXT record in this unmatched doublequote format, zone ends up
in error.

This change verifies that if a TXT record starts with a double quote,
it also ends with a double quote.

Closes-Bug: 1980757
Change-Id: I75bd7c1657a9178c8e7ef2d66fa7318255c67582

designate/objects/rrdata_txt.py

@@ -36,12 +36,22 @@ class TXT(Record):
     def _is_wrapped_in_double_quotes(value):
         return value.startswith('"') and value.endswith('"')
 
+    @staticmethod
+    def _is_missing_double_quote(value):
+        return ((value.startswith('"') and not value.endswith('"')) or
+                (not value.startswith('"') and value.endswith('"')))
+
     def _validate_record_single_string(self, value):
         if len(value) > 255:
             err = ("Any TXT record string exceeding "
                    "255 characters has to be split.")
             raise InvalidObject(err)
 
+        if self._is_missing_double_quote(value):
+            err = ("TXT record is missing a double quote either at beginning "
+                   "or at end.")
+            raise InvalidObject(err)
+
         if not self._is_wrapped_in_double_quotes(value):
             # value with spaces should be quoted as per RFC1035 5.1
             for element in value:

designate/tests/unit/objects/test_rrdata_txt.py

@@ -44,3 +44,20 @@ class RRDataTXTTest(oslotest.base.BaseTestCase):
             'Provided object does not match schema',
             record.validate
         )
+
+    def test_reject_non_matched_quotes(self):
+        record = objects.TXT()
+        self.assertRaisesRegex(
+            exceptions.InvalidObject,
+            "TXT record is missing a double quote either at beginning "
+            "or at end.",
+            record._from_string,
+            '"foo'
+        )
+        self.assertRaisesRegex(
+            exceptions.InvalidObject,
+            "TXT record is missing a double quote either at beginning "
+            "or at end.",
+            record._from_string,
+            'foo"'
+        )

releasenotes/notes/validate-doublequotes-6c4ed4f65a9d5e4b.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - Verify that if a TXT record starts with a double quote, it also ends with
+    a double quote.