Add a test for the axolotl API

src/axolotl.cpp

@@ -67,7 +67,6 @@ std::size_t enc_output(
     std::size_t length = ciphertext_length + PICKLE_CIPHER.mac_length();
     std::size_t base64_length = axolotl::encode_base64_length(length);
     std::uint8_t * raw_output = output + base64_length - length;
-    length -= PICKLE_CIPHER.mac_length();
     PICKLE_CIPHER.encrypt(
         key, key_length,
         raw_output, raw_length,
@@ -395,6 +394,12 @@ size_t axolotl_account_one_time_keys(
 }
 
 
+size_t axolotl_create_outbound_session_random_length(
+    AxolotlSession * session
+) {
+    return from_c(session)->new_outbound_session_random_length();
+}
+
 size_t axolotl_create_outbound_session(
     AxolotlSession * session,
     AxolotlAccount * account,

src/crypto.cpp

@@ -237,15 +237,18 @@ std::size_t axolotl::aes_decrypt_cbc(
 ) {
     std::uint32_t key_schedule[60];
     ::aes_key_setup(key.key, key_schedule, 256);
+    std::uint8_t block1[AES_BLOCK_LENGTH];
+    std::uint8_t block2[AES_BLOCK_LENGTH];
+    std::memcpy(block1, iv.iv, AES_BLOCK_LENGTH);
     for (std::size_t i = 0; i < input_length; i += AES_BLOCK_LENGTH) {
+        std::memcpy(block2, &input[i], AES_BLOCK_LENGTH);
         ::aes_decrypt(&input[i], &output[i], key_schedule, 256);
-        if (i == 0) {
-            xor_block<AES_BLOCK_LENGTH>(&output[i], iv.iv);
-        } else {
-            xor_block<AES_BLOCK_LENGTH>(&output[i], &input[i - AES_BLOCK_LENGTH]);
-        }
+        xor_block<AES_BLOCK_LENGTH>(&output[i], block1);
+        std::memcpy(block1, block2, AES_BLOCK_LENGTH);
     }
     axolotl::unset(key_schedule);
+    axolotl::unset(block1);
+    axolotl::unset(block2);
     std::size_t padding = output[input_length - 1];
     return (padding > input_length) ? std::size_t(-1) : (input_length - padding);
 }

src/ratchet.cpp

@@ -141,12 +141,12 @@ std::size_t verify_mac_and_decrypt_for_new_chain(
     /* They shouldn't move to a new chain until we've sent them a message
      * acknowledging the last one */
     if (session.sender_chain.empty()) {
-        return false;
+        return std::size_t(-1);
     }
 
     /* Limit the number of hashes we're prepared to compute */
     if (reader.counter > MAX_MESSAGE_GAP) {
-        return false;
+        return std::size_t(-1);
     }
     std::memcpy(
         new_chain.ratchet_key.public_key, reader.ratchet_key, KEY_LENGTH
@@ -191,6 +191,7 @@ void axolotl::Ratchet::initialise_as_bob(
         derived_secrets, sizeof(derived_secrets)
     );
     receiver_chains.insert();
+    receiver_chains[0].chain_key.index = 0;
     std::memcpy(root_key, derived_secrets, 32);
     std::memcpy(receiver_chains[0].chain_key.key, derived_secrets + 32, 32);
     receiver_chains[0].ratchet_key = their_ratchet_key;
@@ -210,6 +211,7 @@ void axolotl::Ratchet::initialise_as_alice(
         derived_secrets, sizeof(derived_secrets)
     );
     sender_chain.insert();
+    sender_chain[0].chain_key.index = 0;
     std::memcpy(root_key, derived_secrets, 32);
     std::memcpy(sender_chain[0].chain_key.key, derived_secrets + 32, 32);
     sender_chain[0].ratchet_key = our_ratchet_key;

src/session.cpp

@@ -332,6 +332,8 @@ std::size_t axolotl::Session::decrypt(
     if (result == std::size_t(-1)) {
         last_error = ratchet.last_error;
         ratchet.last_error = axolotl::ErrorCode::SUCCESS;
+    } else {
+        received_message = true;
     }
     return result;
 }

tests/include/unittest.hh

@@ -53,6 +53,25 @@ void assert_equals(
     }
 }
 
+template<typename T>
+void assert_not_equals(
+    const char *file,
+    unsigned line,
+    const char *expected_expr,
+    const char *actual_expr,
+    T const & expected,
+    T const & actual
+) {
+    if (expected == actual) {
+        std::cout << "FAILED: " << TEST_CASE << std::endl;
+        std::cout << file << ":" << line << std::endl;
+        std::cout << expected_expr << " == " << actual_expr << std::endl;
+        std::cout << "Unexpected: " << expected << std::endl;
+        std::cout << "Actual:   " << actual << std::endl;
+        std::exit(1);
+    }
+}
+
 
 void assert_equals(
     const char *file,
@@ -77,6 +96,10 @@ void assert_equals(
     __FILE__, __LINE__, #expected, #actual, expected, actual, ##__VA_ARGS__ \
 )
 
+#define assert_not_equals(expected, actual, ...) assert_not_equals( \
+    __FILE__, __LINE__, #expected, #actual, expected, actual, ##__VA_ARGS__ \
+)
+
 class TestCase  {
 public:
     TestCase(const char *name) { TEST_CASE = name; }

tests/test_axolotl.cpp

@@ -0,0 +1,135 @@
+#include "axolotl/axolotl.hh"
+#include "unittest.hh"
+
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+
+int main() {
+
+{ /** Pickle account test */
+
+TestCase test_case("Pickle account test");
+
+std::uint8_t account_buffer[::axolotl_account_size()];
+::AxolotlAccount *account = ::axolotl_account(account_buffer);
+std::size_t random_length = ::axolotl_create_account_random_length(account);
+std::uint8_t random[random_length];
+std::memset(random, 4, random_length); /* http://xkcd.com/221/ */
+::axolotl_create_account(account, random, random_length);
+std::size_t pickle_length = ::axolotl_pickle_account_length(account);
+std::uint8_t pickle1[pickle_length];
+::axolotl_pickle_account(account, "secret_key", 10, pickle1, pickle_length);
+std::uint8_t pickle2[pickle_length];
+std::memcpy(pickle2, pickle1, pickle_length);
+
+std::uint8_t account_buffer2[::axolotl_account_size()];
+::AxolotlAccount *account2 = ::axolotl_account(account_buffer2);
+::axolotl_unpickle_account(account2, "secret_key", 10, pickle2, pickle_length);
+assert_equals(pickle_length, ::axolotl_pickle_account_length(account2));
+::axolotl_pickle_account(account2, "secret_key", 10, pickle2, pickle_length);
+
+assert_equals(pickle1, pickle2, pickle_length);
+
+}
+
+{ /** Loopback test */
+
+TestCase test_case("Loopback test");
+
+std::uint8_t a_account_buffer[::axolotl_account_size()];
+::AxolotlAccount *a_account = ::axolotl_account(a_account_buffer);
+std::uint8_t a_random[::axolotl_create_account_random_length(a_account)];
+std::memset(a_random, 4, sizeof(a_random)); /* http://xkcd.com/221/ */
+::axolotl_create_account(a_account, a_random, sizeof(a_random));
+
+std::uint8_t b_account_buffer[::axolotl_account_size()];
+::AxolotlAccount *b_account = ::axolotl_account(b_account_buffer);
+std::uint8_t b_random[::axolotl_create_account_random_length(b_account)];
+std::memset(b_random, 5, sizeof(b_random)); /* http://xkcd.com/221/ */
+::axolotl_create_account(b_account, b_random, sizeof(b_random));
+
+std::uint8_t b_id_keys[::axolotl_account_identity_keys_length(b_account)];
+std::uint8_t b_ot_keys[::axolotl_account_one_time_keys_length(b_account)];
+::axolotl_account_identity_keys(b_account, b_id_keys, sizeof(b_id_keys));
+::axolotl_account_one_time_keys(b_account, b_ot_keys, sizeof(b_ot_keys));
+
+std::uint8_t a_session_buffer[::axolotl_session_size()];
+::AxolotlSession *a_session = ::axolotl_session(a_session_buffer);
+std::uint8_t a_rand[::axolotl_create_outbound_session_random_length(a_session)];
+std::memset(b_random, 6, sizeof(a_rand)); /* http://xkcd.com/221/ */
+assert_not_equals(std::size_t(-1), ::axolotl_create_outbound_session(
+    a_session, a_account,
+    b_id_keys + 14, 43,
+    ::atol((char *)(b_ot_keys + 62)), b_ot_keys + 74, 43,
+    a_rand, sizeof(a_rand)
+));
+
+std::uint8_t plaintext[] = "Hello, World";
+std::uint8_t message_1[::axolotl_encrypt_message_length(a_session, 12)];
+std::uint8_t a_message_random[::axolotl_encrypt_random_length(a_session)];
+assert_equals(std::size_t(0), ::axolotl_encrypt_message_type(a_session));
+assert_not_equals(std::size_t(-1), ::axolotl_encrypt(
+    a_session,
+    plaintext, 12,
+    a_message_random, sizeof(a_message_random),
+    message_1, sizeof(message_1)
+));
+
+
+std::uint8_t tmp_message_1[sizeof(message_1)];
+std::memcpy(tmp_message_1, message_1, sizeof(message_1));
+std::uint8_t b_session_buffer[::axolotl_account_size()];
+::AxolotlSession *b_session = ::axolotl_session(b_session_buffer);
+::axolotl_create_inbound_session(
+    b_session, b_account, tmp_message_1, sizeof(message_1)
+);
+
+std::memcpy(tmp_message_1, message_1, sizeof(message_1));
+std::uint8_t plaintext_1[::axolotl_decrypt_max_plaintext_length(
+    b_session, 0, tmp_message_1, sizeof(message_1)
+)];
+std::memcpy(tmp_message_1, message_1, sizeof(message_1));
+assert_equals(std::size_t(12), ::axolotl_decrypt(
+    b_session, 0,
+    tmp_message_1, sizeof(message_1),
+    plaintext_1, sizeof(plaintext_1)
+));
+
+assert_equals(plaintext, plaintext_1, 12);
+
+std::uint8_t message_2[::axolotl_encrypt_message_length(b_session, 12)];
+std::uint8_t b_message_random[::axolotl_encrypt_random_length(b_session)];
+assert_equals(std::size_t(1), ::axolotl_encrypt_message_type(b_session));
+assert_not_equals(std::size_t(-1), ::axolotl_encrypt(
+    b_session,
+    plaintext, 12,
+    b_message_random, sizeof(b_message_random),
+    message_2, sizeof(message_2)
+));
+
+std::uint8_t tmp_message_2[sizeof(message_2)];
+std::memcpy(tmp_message_2, message_2, sizeof(message_2));
+std::uint8_t plaintext_2[::axolotl_decrypt_max_plaintext_length(
+    a_session, 1, tmp_message_2, sizeof(message_2)
+)];
+std::memcpy(tmp_message_2, message_2, sizeof(message_2));
+assert_equals(std::size_t(12), ::axolotl_decrypt(
+    a_session, 1,
+    tmp_message_2, sizeof(message_2),
+    plaintext_2, sizeof(plaintext_2)
+));
+
+assert_equals(plaintext, plaintext_2, 12);
+
+std::memcpy(tmp_message_2, message_2, sizeof(message_2));
+assert_equals(std::size_t(-1), ::axolotl_decrypt(
+    a_session, 1,
+    tmp_message_2, sizeof(message_2),
+    plaintext_2, sizeof(plaintext_2)
+));
+
+
+}
+
+}

tests/test_base64.cpp

@@ -1,4 +1,3 @@
-
 #include "axolotl/base64.hh"
 #include "unittest.hh"