supported groups extension with a truncated array element

prober.py

@@ -191,7 +191,10 @@
     CertTypeOverflow12PFS(),
     SupportedGroupsNull(),
     SupportedGroupsNull12(),
-    SupportedGroupsNull12PFS()
+    SupportedGroupsNull12PFS(),
+    SupportedGroupsOddLen(),
+    SupportedGroupsOddLen12(),
+    SupportedGroupsOddLen12PFS()
 ]
 
 def probe(ipaddress, port, starttls, specified_probe):

probes.py

@@ -1778,3 +1778,23 @@ class SupportedGroupsNull12(SupportedGroupsNull, NormalHandshake12):
 class SupportedGroupsNull12PFS(SupportedGroupsNull, NormalHandshake12PFS):
     '''Send empty supported groups extension in PFS TLSv1.2 hello'''
     pass
+
+
+class SupportedGroupsOddLen(SupportedGroupsNull):
+    '''Send supported groups extension with invalid length in hello'''
+
+    def test(self, sock):
+        logging.debug('Sending Client Hello...')
+        # normal extension has a two byte length and two byte elements,
+        # truncate the second element
+        sock.write(self.make_supported_groups_hello(b'\x00\x03\x00\x17\x00'))
+
+
+class SupportedGroupsOddLen12(SupportedGroupsOddLen, NormalHandshake12):
+    '''Send supported groups extension with invalid length in TLSv1.2 hello'''
+    pass
+
+
+class SupportedGroupsOddLen12PFS(SupportedGroupsOddLen, NormalHandshake12PFS):
+    '''As with SupportedGroupsOddLen but in PFS TLSv1.2 hello'''
+    pass

tests/test_probes.py

@@ -3578,3 +3578,68 @@ def test_test(self):
                           b'\x01\x00'
                           b'\x00\x04'
                           b'\x00\x0a\x00\x00'])
+
+
+class TestSupportedGroupsOddLen(unittest.TestCase):
+    def test_test(self):
+        probe = SupportedGroupsOddLen()
+        sock = MockSock()
+
+        probe.test(sock)
+
+        self.maxDiff = None
+        self.assertEqual(sock.sent_data,
+                         [b'\x16\x03\x01\x00D'
+                          b'\x01\x00\x00@'
+                          b'\x03\x01' +
+                          RANDOM_STR +
+                          b'\x00'
+                          b'\x00\x0e' +
+                          DEFAULT_CIPHERS_STR +
+                          b'\x01\x00'
+                          b'\x00\x09'
+                          b'\x00\x0a\x00\x05'
+                          b'\x00\x03\x00\x17\x00'])
+
+
+class TestSupportedGroupsOddLen12(unittest.TestCase):
+    def test_test(self):
+        probe = SupportedGroupsOddLen12()
+        sock = MockSock()
+
+        probe.test(sock)
+
+        self.assertEqual(sock.sent_data,
+                         [b'\x16\x03\x01\x00\\'
+                          b'\x01\x00\x00X'
+                          b'\x03\x03' +
+                          RANDOM_STR +
+                          b'\x00'
+                          b'\x00&' +
+                          DEFAULT_12_CIPHERS_STR +
+                          b'\x01\x00'
+                          b'\x00\x09'
+                          b'\x00\x0a\x00\x05'
+                          b'\x00\x03\x00\x17\x00'])
+
+
+class TestSupportedGroupsOddLen12PFS(unittest.TestCase):
+    def test_test(self):
+        probe = SupportedGroupsOddLen12PFS()
+        sock = MockSock()
+
+        probe.test(sock)
+
+        self.maxDiff = None
+        self.assertEqual(sock.sent_data,
+                         [b"\x16\x03\x01\x00\x94"
+                          b"\x01\x00\x00\x90"
+                          b"\x03\x03" +
+                          RANDOM_STR +
+                          b"\x00"
+                          b"\x00^" +
+                          DEFAULT_PFS_CIPHERS_STR +
+                          b"\x01\x00"
+                          b'\x00\x09'
+                          b'\x00\x0a\x00\x05'
+                          b'\x00\x03\x00\x17\x00'])