deny insecure parameters by default

[python-delta-tar] / testing / test_crypto.py

diff --git a/testing/test_crypto.py b/testing/test_crypto.py
index 41b38d7..f47c7c7 100644 (file)
--- a/testing/test_crypto.py
+++ b/testing/test_crypto.py
@@ -21,6 +21,7 @@ TEST_DUMMY_FILENAME  = "insurance-file.txt"
 TEST_VERSION         = 1
 TEST_PARAMVERSION    = 1
 TEST_STATIC_NACL     = os.urandom (CRYPTO_NACL_SIZE)
+PLAIN_PARAMVERSION   = 0
 
 def faux_hdr (ctsize=1337, iv=None):
     return \
@@ -81,6 +82,28 @@ class AESGCMTest (CryptoLayerTest):
                                      password=password,
                                      nacl=TEST_STATIC_NACL)
 
+    def test_crypto_aes_gcm_enc_ctor_bad_plainparams (self):
+        """Refuse plaintext passthrough mode by default."""
+        password   = str (os.urandom (42))
+        with self.assertRaises (crypto.InvalidParameter):
+            encryptor  = crypto.Encrypt (TEST_VERSION,
+                                         PLAIN_PARAMVERSION,
+                                         password=password,
+                                         nacl=TEST_STATIC_NACL)
+
+
+    def test_crypto_aes_gcm_enc_ctor_ok_insecure_plainparams (self):
+        """
+        Comply with request for plaintext passthrough mode if the
+        *insecure* flag is passed.
+        """
+        password   = str (os.urandom (42))
+        encryptor  = crypto.Encrypt (TEST_VERSION,
+                                        PLAIN_PARAMVERSION,
+                                        password=password,
+                                        nacl=TEST_STATIC_NACL,
+                                        insecure=True)
+
 
     def test_crypto_aes_gcm_enc_ctor_key (self):
         key        = os.urandom (42)
@@ -190,6 +213,64 @@ class AESGCMTest (CryptoLayerTest):
         assert plaintext == TEST_PLAINTEXT
 
 
+    def test_crypto_aes_gcm_dec_plain_bad (self):
+        """
+        Downgrade to plaintext must not be allowed in parameters
+        obtained from headers.
+        """
+        password       = str (os.urandom (42))
+        encryptor      = crypto.Encrypt (TEST_VERSION,
+                                         TEST_PARAMVERSION,
+                                         password=password,
+                                         nacl=TEST_STATIC_NACL)
+
+        header_dummy   = encryptor.next (TEST_DUMMY_FILENAME)
+        _, ciphertext  = encryptor.process (TEST_PLAINTEXT)
+        rest, header, fixed = encryptor.done (header_dummy)
+        ciphertext    += rest
+
+        header         = crypto.hdr_read (header)
+        header ["paramversion"] = PLAIN_PARAMVERSION
+        ok, header     = crypto.hdr_make (header)
+        assert ok
+
+        decryptor      = crypto.Decrypt (password=password, fixedparts=fixed)
+        with self.assertRaises (crypto.InvalidParameter):
+            decryptor.next (header)
+
+
+    def test_crypto_aes_gcm_dec_plain_ok_insecure (self):
+        """
+        Allow plaintext crypto mode if *insecure* flag is passed.
+        """
+        password       = str (os.urandom (42))
+        encryptor      = crypto.Encrypt (TEST_VERSION,
+                                         PLAIN_PARAMVERSION,
+                                         password=password,
+                                         nacl=TEST_STATIC_NACL,
+                                         insecure=True)
+
+        header_dummy   = encryptor.next (TEST_DUMMY_FILENAME)
+        _, ciphertext  = encryptor.process (TEST_PLAINTEXT)
+        rest, header, fixed = encryptor.done (header_dummy)
+        ciphertext    += rest
+
+        header         = crypto.hdr_read (header)
+        header ["paramversion"] = PLAIN_PARAMVERSION
+        ok, header     = crypto.hdr_make (header)
+        assert ok
+
+        decryptor      = crypto.Decrypt (password=password,
+                                         fixedparts=fixed,
+                                         insecure=True)
+        decryptor.next (header)
+        plaintext      = decryptor.process (ciphertext)
+        rest           = decryptor.done ()
+        plaintext     += rest
+
+        assert plaintext == TEST_PLAINTEXT
+
+
     def test_crypto_aes_gcm_dec_bad_tag (self):
         password       = str (os.urandom (42))
         encryptor      = crypto.Encrypt (TEST_VERSION,