add probe with an invalid ciphers length filed

cipher id's are encoded in two bytes, thus the length field of the
ciphers array must always be even, see what happens if we send an array
with odd number of bytes

prober.py

@@ -60,6 +60,9 @@
     InvalidSessionID(),
     InvalidSessionID12(),
     InvalidSessionID12PFS(),
+    InvalidCiphersLength(),
+    InvalidCiphersLength12(),
+    InvalidCiphersLength12PFS(),
     DoubleClientHello(),
     DoubleClientHello12(),
     DoubleClientHello12PFS(),

probes.py

@@ -256,6 +256,53 @@ def __init__(self):
         self.ciphers = DEFAULT_PFS_CIPHERS
 
 
+class InvalidCiphersLength(Probe):
+    '''Send client hello with length field of ciphers that is invalid (odd)'''
+
+    def __init__(self):
+        super(InvalidCiphersLength, self).__init__()
+        self.hello_version = TLSRecord.TLS1_0
+        self.ciphers = DEFAULT_CIPHERS
+
+    def make_hello(self, version, cipher_suites):
+        cipher_bytes = struct.pack('>{0}H'.format(len(cipher_suites)),
+                                   *cipher_suites) + b'\x00'
+        ciphers = struct.pack('>H', len(cipher_bytes)) + cipher_bytes
+        hello = (struct.pack('>H32sB', version,
+                             b'01234567890123456789012345678901',
+                             0) +
+                 ciphers + b'\x01\x00' + b'\x00\x00')
+
+        hello_msg = HandshakeMessage.create(HandshakeMessage.ClientHello,
+                                            hello)
+
+        record = TLSRecord.create(content_type=TLSRecord.Handshake,
+                                  version=TLSRecord.TLS1_0,
+                                  message=hello_msg.bytes)
+        return record.bytes
+
+    def test(self, sock):
+        logging.debug('Sending Client Helo...')
+        sock.write(self.make_hello(self.hello_version, self.ciphers))
+
+class InvalidCiphersLength12(InvalidCiphersLength):
+    '''As with InvalidCiphersLength but with TLSv1.2 helo'''
+
+    def __init__(self):
+        super(InvalidCiphersLength12, self).__init__()
+        self.hello_version = TLSRecord.TLS1_2
+        self.ciphers = DEFAULT_12_CIPHERS
+
+
+class InvalidCiphersLength12PFS(InvalidCiphersLength):
+    '''As with InvalidCiphersLength but with PFS TLSv1.2 hello'''
+
+    def __init__(self):
+        super(InvalidCiphersLength12PFS, self).__init__()
+        self.hello_version = TLSRecord.TLS1_2
+        self.ciphers = DEFAULT_PFS_CIPHERS
+
+
 class DoubleClientHello(NormalHandshake):
     '''Two client hellos'''
 

tests/test_probes.py

@@ -314,6 +314,64 @@ def test_test(self):
                           b'\x00\x00'])
 
 
+class TestInvalidCiphersLength(unittest.TestCase):
+    def test_test(self):
+        probe = InvalidCiphersLength()
+        sock = MockSock()
+
+        probe.test(sock)
+
+        self.assertEqual(sock.sent_data,
+                         [b'\x16\x03\x01\x00<'
+                          b'\x01\x00\x008'
+                          b'\x03\01' +
+                          RANDOM_STR +
+                          b'\x00'
+                          b'\x00\x0f' +
+                          DEFAULT_CIPHERS_STR + b'\x00'
+                          b'\x01\x00'
+                          b'\x00\x00'])
+
+
+class TestInvalidCiphersLength12(unittest.TestCase):
+    def test_test(self):
+        probe = InvalidCiphersLength12()
+        sock = MockSock()
+
+        probe.test(sock)
+
+        self.maxDiff = None
+        self.assertEqual(sock.sent_data,
+                         [b'\x16\x03\x01\x00T'
+                          b'\x01\x00\x00P'
+                          b'\x03\03' +
+                          RANDOM_STR +
+                          b'\x00'
+                          b"\x00'" +
+                          DEFAULT_12_CIPHERS_STR + b'\x00'
+                          b'\x01\x00'
+                          b'\x00\x00'])
+
+
+class TestInvalidCiphersLength12PFS(unittest.TestCase):
+    def test_test(self):
+        probe = InvalidCiphersLength12PFS()
+        sock = MockSock()
+
+        probe.test(sock)
+
+        self.maxDiff = None
+        self.assertEqual(sock.sent_data,
+                         [b'\x16\x03\x01\x00\x8c'
+                          b'\x01\x00\x00\x88'
+                          b'\x03\03' +
+                          RANDOM_STR +
+                          b'\x00'
+                          b'\x00_' +
+                          DEFAULT_PFS_CIPHERS_STR + b'\x00'
+                          b'\x01\x00'
+                          b'\x00\x00'])
+
 
 class TestDoubleClientHello(unittest.TestCase):
     def test_test(self):