Consolidate NSEC/NSEC3/CSYNC bitmap handling.

This also fixes several bugs; the NSEC3 code would properly avoid empty
windows, but the NSEC and CSYNC code did not.  Also, none of the wire
parsing routines properly checked to see that the window number was
monotonically increasing.

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/test_nsec3.py b/tests/test_nsec3.py
index 0b75b29..bf7d115 100644
--- a/tests/test_nsec3.py
+++ b/tests/test_nsec3.py
@@ -17,6 +17,7 @@
 
 import unittest
 
+import dns.exception
 import dns.rdata
 import dns.rdataclass
 import dns.rdatatype
@@ -34,5 +35,14 @@ class NSEC3TestCase(unittest.TestCase):
                                          (255, bitmap)
                                          ))
 
+    def test_NSEC3_bad_bitmaps(self):
+        rdata = dns.rdata.from_text(dns.rdataclass.IN, dns.rdatatype.NSEC3,
+                u"1 0 100 ABCD SCBCQHKU35969L2A68P3AD59LHF30715 A CAA")
+
+        with self.assertRaises(dns.exception.FormError):
+            copy = bytearray(rdata.to_wire())
+            copy[-3] = 0
+            dns.rdata.from_wire('IN', 'NSEC3', copy, 0, len(copy))
+
 if __name__ == '__main__':
     unittest.main()