Re-enable logging

A separate branch which retains logging functionality, for debugging and/or
documentation purposes.

(This branch is currently lacking support for C sources, so won't compile
correctly.)

include/olm/logging.h

@@ -0,0 +1,44 @@
+/* Copyright 2016 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef OLM_LOGGING_H_
+#define OLM_LOGGING_H_
+
+#include "olm/olm.hh"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define OLM_LOG_FATAL   1
+#define OLM_LOG_ERROR   2
+#define OLM_LOG_WARNING 3
+#define OLM_LOG_INFO    4
+#define OLM_LOG_DEBUG   5
+#define OLM_LOG_TRACE   6
+
+/* returns non-zero if logging is enabled for this level */
+int olm_log_enabled_for(unsigned int level, const char *category);
+
+__attribute__((__format__ (__printf__, 3, 4)))
+void olm_logf(unsigned int level, const char *category,
+          const char *format, ...);
+
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif /* OLM_LOGGING_H_ */

src/account.cpp

@@ -14,9 +14,12 @@
  */
 #include "olm/account.hh"
 #include "olm/base64.hh"
+#include "olm/logging.h"
 #include "olm/pickle.hh"
 #include "olm/memory.hh"
 
+static const char *LOG_CATEGORY = "olm::Account";
+
 olm::Account::Account(
 ) : next_one_time_key_id(0),
     last_error(olm::ErrorCode::SUCCESS) {
@@ -42,9 +45,11 @@ std::size_t olm::Account::remove_key(
         if (olm::array_equal(i->key.public_key, public_key.public_key)) {
             std::uint32_t id = i->id;
             one_time_keys.erase(i);
+            olm_logf(OLM_LOG_INFO, LOG_CATEGORY, "removed key id %i", id);
             return id;
         }
     }
+    olm_logf(OLM_LOG_WARNING, LOG_CATEGORY, "Couldn't find key to remove");
     return std::size_t(-1);
 }
 
@@ -64,6 +69,8 @@ std::size_t olm::Account::new_account(
     random += KEY_LENGTH;
     olm::curve25519_generate_key(random, identity_keys.curve25519_key);
 
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Created new account");
+
     return 0;
 }
 

src/logging.c

@@ -0,0 +1,47 @@
+/* Copyright 2016 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "olm/logging.h"
+
+#include <stdarg.h>
+#include <stdio.h>
+
+static unsigned int log_level = 1;
+
+void olm_set_log_level(unsigned int level) {
+    log_level = level;
+}
+
+int olm_log_enabled_for(unsigned int level, const char *category)
+{
+    return level <= log_level;
+}
+
+void olm_logf(unsigned int level, const char *category,
+          const char *format, ...) {
+    if (level > log_level) {
+        return;
+    }
+
+    fputs(category, stdout);
+    fputs(": ", stdout);
+
+    va_list ap;
+    va_start(ap, format);
+    vprintf(format, ap);
+    va_end(ap);
+
+    putchar('\n');
+}

src/message.cpp

@@ -14,10 +14,13 @@
  */
 #include "olm/message.hh"
 
+#include "olm/logging.h"
 #include "olm/memory.hh"
 
 namespace {
 
+static const char *LOG_CATEGORY = "olm::Message";
+
 template<typename T>
 static std::size_t varint_length(
     T value
@@ -236,6 +239,13 @@ void olm::decode_message(
         }
         unknown = pos;
     }
+    olm_logf(OLM_LOG_TRACE, LOG_CATEGORY,
+              "Decoded message ver=%i ratchet_key=%s chain_idx=%i ciphertext=%s",
+              reader.version,
+              olm::bytes_to_string(reader.ratchet_key, reader.ratchet_key_length).c_str(),
+              reader.has_counter ? reader.counter : -1,
+              olm::bytes_to_string(reader.ciphertext, reader.ciphertext_length).c_str()
+    );
 }
 
 
@@ -324,4 +334,14 @@ void olm::decode_one_time_key_message(
         }
         unknown = pos;
     }
+
+    olm_logf(OLM_LOG_TRACE, LOG_CATEGORY,
+              "Decoded pre-key message ver=%i one_time_key[Eb]=%s "
+              "base_key[Ea]=%s identity_key[Ia]=%s message=%s",
+              reader.version,
+              olm::bytes_to_string(reader.one_time_key, reader.one_time_key_length).c_str(),
+              olm::bytes_to_string(reader.base_key, reader.base_key_length).c_str(),
+              olm::bytes_to_string(reader.identity_key, reader.identity_key_length).c_str(),
+              olm::bytes_to_string(reader.message, reader.message_length).c_str()
+    );
 }

src/olm.cpp

@@ -19,6 +19,7 @@
 #include "olm/base64.hh"
 #include "olm/cipher.hh"
 #include "olm/memory.hh"
+#include "olm/logging.h"
 
 #include <new>
 #include <cstring>

src/ratchet.cpp

@@ -17,11 +17,14 @@
 #include "olm/memory.hh"
 #include "olm/cipher.hh"
 #include "olm/pickle.hh"
+#include "olm/logging.h"
 
 #include <cstring>
 
 namespace {
 
+static const char *LOG_CATEGORY = "olm::Ratchet";
+
 static const std::uint8_t PROTOCOL_VERSION = 3;
 static const std::uint8_t MESSAGE_KEY_SEED[1] = {0x01};
 static const std::uint8_t CHAIN_KEY_SEED[1] = {0x02};
@@ -76,6 +79,8 @@ static void advance_chain_key(
         new_chain_key.key
     );
     new_chain_key.index = chain_key.index + 1;
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Derived chain key C(%i,%i)",
+              chain_index, new_chain_key.index);
 }
 
 
@@ -90,6 +95,8 @@ static void create_message_keys(
         message_key.key
     );
     message_key.index = chain_key.index;
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Created message key with chain key C(%i,%i)",
+              chain_index, message_key.index);
 }
 
 
@@ -169,6 +176,9 @@ static std::size_t verify_mac_and_decrypt_for_new_chain(
         new_chain.ratchet_key, session.kdf_info,
         new_root_key, new_chain.chain_key
     );
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Calculated new receiver chain R(%i)",
+                  chain_index);
+
     std::size_t result = verify_mac_and_decrypt_for_existing_chain(
         session, chain_index, new_chain.chain_key, reader,
         plaintext, max_plaintext_length
@@ -209,6 +219,7 @@ void olm::Ratchet::initialise_as_bob(
     receiver_chains[0].ratchet_key = their_ratchet_key;
     chain_index = 0;
     olm::unset(derived_secrets);
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Initialised receiver chain R(0)");
 }
 
 
@@ -231,6 +242,7 @@ void olm::Ratchet::initialise_as_alice(
     sender_chain[0].ratchet_key = our_ratchet_key;
     chain_index = 0;
     olm::unset(derived_secrets);
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Initialised sender chain R(0)");
 }
 
 namespace olm {
@@ -438,6 +450,9 @@ std::size_t olm::Ratchet::encrypt(
     if (sender_chain.empty()) {
         sender_chain.insert();
         olm::curve25519_generate_key(random, sender_chain[0].ratchet_key);
+        olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Created new ratchet key T(%i) %s",
+                  chain_index + 1,
+                  sender_chain[0].ratchet_key.to_string().c_str());
         create_chain_key(
             root_key,
             sender_chain[0].ratchet_key,
@@ -445,6 +460,8 @@ std::size_t olm::Ratchet::encrypt(
             kdf_info,
             root_key, sender_chain[0].chain_key
         );
+        olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Initialised new sender chain R(%i)",
+                  chain_index + 1);
         chain_index++;
     }
 
@@ -474,6 +491,14 @@ std::size_t olm::Ratchet::encrypt(
         output, output_length
     );
 
+    olm_logf(OLM_LOG_TRACE, LOG_CATEGORY,
+              "Encoded message ver=%i ratchet_key=%s chain_idx=%i ciphertext=%s",
+              PROTOCOL_VERSION,
+              olm::bytes_to_string(writer.ratchet_key, olm::KEY_LENGTH).c_str(),
+              counter,
+              olm::bytes_to_string(writer.ciphertext, ciphertext_length).c_str()
+    );
+
     olm::unset(keys);
     return output_length;
 }
@@ -500,6 +525,10 @@ std::size_t olm::Ratchet::decrypt(
     std::uint8_t const * input, std::size_t input_length,
     std::uint8_t * plaintext, std::size_t max_plaintext_length
 ) {
+    olm_logf(OLM_LOG_TRACE, LOG_CATEGORY,
+              "Decrypting message %s",
+              olm::bytes_to_string(input, input_length).c_str());
+
     olm::MessageReader reader;
     olm::decode_message(
         reader, input, input_length, ratchet_cipher.mac_length()
@@ -551,6 +580,8 @@ std::size_t olm::Ratchet::decrypt(
     std::size_t result = std::size_t(-1);
 
     if (!chain) {
+        olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY,
+                  "Sender ratchet key does not match known chain; starting new one");
         result = verify_mac_and_decrypt_for_new_chain(
             *this, reader, plaintext, max_plaintext_length
         );
@@ -611,6 +642,8 @@ std::size_t olm::Ratchet::decrypt(
         olm::unset(sender_chain[0]);
         sender_chain.erase(sender_chain.begin());
         receiver_chain_index = ++chain_index;
+        olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Initialised new receiver chain R(%i)",
+                  chain_index);
     }
 
     while (chain->chain_key.index < reader.counter) {

src/session.cpp

@@ -16,6 +16,7 @@
 #include "olm/cipher.hh"
 #include "olm/crypto.hh"
 #include "olm/account.hh"
+#include "olm/logging.h"
 #include "olm/memory.hh"
 #include "olm/message.hh"
 #include "olm/pickle.hh"
@@ -24,6 +25,8 @@
 
 namespace {
 
+static const char *LOG_CATEGORY = "olm::Session";
+
 static const std::uint8_t PROTOCOL_VERSION = 0x3;
 
 static const std::uint8_t ROOT_KDF_INFO[] = "OLM_ROOT";
@@ -65,11 +68,21 @@ std::size_t olm::Session::new_outbound_session(
         return std::size_t(-1);
     }
 
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY,
+              "Creating new outbound session to receiver identity IB %s, "
+              "receiver ephemeral EB %s", identity_key.to_string().c_str(),
+              one_time_key.to_string().c_str()
+    );
+
     olm::Curve25519KeyPair base_key;
     olm::curve25519_generate_key(random, base_key);
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Created new ephemeral key EA %s",
+              base_key.to_string().c_str());
 
     olm::Curve25519KeyPair ratchet_key;
     olm::curve25519_generate_key(random + olm::KEY_LENGTH, ratchet_key);
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Created new ratchet key T(0) %s",
+              ratchet_key.to_string().c_str());
 
     olm::Curve25519KeyPair const & alice_identity_key_pair = (
         local_account.identity_keys.curve25519_key
@@ -95,6 +108,7 @@ std::size_t olm::Session::new_outbound_session(
     olm::unset(ratchet_key);
     olm::unset(secret);
 
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Initialised outbound session");
     return std::size_t(0);
 }
 
@@ -137,6 +151,13 @@ std::size_t olm::Session::new_inbound_session(
             their_identity_key->public_key, reader.identity_key, olm::KEY_LENGTH
         );
         if (!same) {
+            olm_logf(OLM_LOG_INFO, LOG_CATEGORY,
+                      "Identity key on received message is incorrect "
+                      "(expected %s, got %s)",
+                      their_identity_key->to_string().c_str(),
+                      olm::bytes_to_string(reader.identity_key,
+                                           reader.identity_key + olm::KEY_LENGTH)
+                          .c_str());
             last_error = olm::ErrorCode::BAD_MESSAGE_KEY_ID;
             return std::size_t(-1);
         }
@@ -146,6 +167,13 @@ std::size_t olm::Session::new_inbound_session(
     olm::load_array(alice_base_key.public_key, reader.base_key);
     olm::load_array(bob_one_time_key.public_key, reader.one_time_key);
 
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY,
+              "Creating new inbound session from sender identity IA %s, "
+              "sender ephemeral EA %s, our ephemeral EB %s",
+              alice_identity_key.to_string().c_str(),
+              alice_base_key.to_string().c_str(),
+              bob_one_time_key.to_string().c_str());
+
     olm::MessageReader message_reader;
     decode_message(
         message_reader, reader.message, reader.message_length,
@@ -161,11 +189,17 @@ std::size_t olm::Session::new_inbound_session(
     olm::Curve25519PublicKey ratchet_key;
     olm::load_array(ratchet_key.public_key, message_reader.ratchet_key);
 
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY,
+              "Received ratchet key T(0) %s", ratchet_key.to_string().c_str());
+
     olm::OneTimeKey const * our_one_time_key = local_account.lookup_key(
         bob_one_time_key
     );
 
     if (!our_one_time_key) {
+        olm_logf(OLM_LOG_INFO, LOG_CATEGORY,
+                  "Session uses unknown ephemeral key %s",
+                  bob_one_time_key.to_string().c_str());
         last_error = olm::ErrorCode::BAD_MESSAGE_KEY_ID;
         return std::size_t(-1);
     }
@@ -187,6 +221,7 @@ std::size_t olm::Session::new_inbound_session(
 
     olm::unset(secret);
 
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Initialised inbound session");
     return std::size_t(0);
 }
 
@@ -285,6 +320,9 @@ std::size_t olm::Session::encrypt(
     std::uint8_t const * random, std::size_t random_length,
     std::uint8_t * message, std::size_t message_length
 ) {
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Encrypting '%.*s'",
+              (int)plaintext_length, plaintext);
+
     if (message_length < encrypt_message_length(plaintext_length)) {
         last_error = olm::ErrorCode::OUTPUT_BUFFER_TOO_SMALL;
         return std::size_t(-1);
@@ -311,6 +349,16 @@ std::size_t olm::Session::encrypt(
         olm::store_array(writer.identity_key, alice_identity_key.public_key);
         olm::store_array(writer.base_key, alice_base_key.public_key);
         message_body = writer.message;
+
+
+        olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY,
+                  "Encoded pre-key message ver=%i one_time_key[Eb]=%s "
+                  "base_key[Ea]=%s identity_key[Ia]=%s",
+                  PROTOCOL_VERSION,
+                  olm::bytes_to_string(writer.one_time_key, olm::KEY_LENGTH).c_str(),
+                  olm::bytes_to_string(writer.base_key, olm::KEY_LENGTH).c_str(),
+                  olm::bytes_to_string(writer.identity_key, olm::KEY_LENGTH).c_str()
+        );
     }
 
     std::size_t result = ratchet.encrypt(
@@ -325,6 +373,9 @@ std::size_t olm::Session::encrypt(
         return result;
     }
 
+    olm_logf(OLM_LOG_TRACE, LOG_CATEGORY, "Encrypted message %s",
+              olm::bytes_to_string(message_body, result).c_str());
+
     return result;
 }
 
@@ -366,6 +417,9 @@ std::size_t olm::Session::decrypt(
     std::uint8_t const * message, std::size_t message_length,
     std::uint8_t * plaintext, std::size_t max_plaintext_length
 ) {
+    olm_logf(OLM_LOG_TRACE, LOG_CATEGORY, "Decrypting %smessage",
+              message_type == olm::MessageType::MESSAGE ? "" : "pre-key ");
+
     std::uint8_t const * message_body;
     std::size_t message_body_length;
     if (message_type == olm::MessageType::MESSAGE) {
@@ -393,6 +447,8 @@ std::size_t olm::Session::decrypt(
     }
 
     received_message = true;
+    olm_logf(OLM_LOG_DEBUG, LOG_CATEGORY, "Decrypted '%.*s'",
+              (int)result, plaintext);
     return result;
 }