--- /dev/null
+/* Copyright 2015-2016 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/message.hh"
+
+#include "olm/memory.hh"
+
+namespace {
+
+template<typename T>
+static std::size_t varint_length(
+ T value
+) {
+ std::size_t result = 1;
+ while (value >= 128U) {
+ ++result;
+ value >>= 7;
+ }
+ return result;
+}
+
+
+template<typename T>
+static std::uint8_t * varint_encode(
+ std::uint8_t * output,
+ T value
+) {
+ while (value >= 128U) {
+ *(output++) = (0x7F & value) | 0x80;
+ value >>= 7;
+ }
+ (*output++) = value;
+ return output;
+}
+
+
+template<typename T>
+static T varint_decode(
+ std::uint8_t const * varint_start,
+ std::uint8_t const * varint_end
+) {
+ T value = 0;
+ if (varint_end == varint_start) {
+ return 0;
+ }
+ do {
+ value <<= 7;
+ value |= 0x7F & *(--varint_end);
+ } while (varint_end != varint_start);
+ return value;
+}
+
+
+static std::uint8_t const * varint_skip(
+ std::uint8_t const * input,
+ std::uint8_t const * input_end
+) {
+ while (input != input_end) {
+ std::uint8_t tmp = *(input++);
+ if ((tmp & 0x80) == 0) {
+ return input;
+ }
+ }
+ return input;
+}
+
+
+static std::size_t varstring_length(
+ std::size_t string_length
+) {
+ return varint_length(string_length) + string_length;
+}
+
+static std::size_t const VERSION_LENGTH = 1;
+static std::uint8_t const RATCHET_KEY_TAG = 012;
+static std::uint8_t const COUNTER_TAG = 020;
+static std::uint8_t const CIPHERTEXT_TAG = 042;
+
+static std::uint8_t * encode(
+ std::uint8_t * pos,
+ std::uint8_t tag,
+ std::uint32_t value
+) {
+ *(pos++) = tag;
+ return varint_encode(pos, value);
+}
+
+static std::uint8_t * encode(
+ std::uint8_t * pos,
+ std::uint8_t tag,
+ std::uint8_t * & value, std::size_t value_length
+) {
+ *(pos++) = tag;
+ pos = varint_encode(pos, value_length);
+ value = pos;
+ return pos + value_length;
+}
+
+static std::uint8_t const * decode(
+ std::uint8_t const * pos, std::uint8_t const * end,
+ std::uint8_t tag,
+ std::uint32_t & value, bool & has_value
+) {
+ if (pos != end && *pos == tag) {
+ ++pos;
+ std::uint8_t const * value_start = pos;
+ pos = varint_skip(pos, end);
+ value = varint_decode<std::uint32_t>(value_start, pos);
+ has_value = true;
+ }
+ return pos;
+}
+
+
+static std::uint8_t const * decode(
+ std::uint8_t const * pos, std::uint8_t const * end,
+ std::uint8_t tag,
+ std::uint8_t const * & value, std::size_t & value_length
+) {
+ if (pos != end && *pos == tag) {
+ ++pos;
+ std::uint8_t const * len_start = pos;
+ pos = varint_skip(pos, end);
+ std::size_t len = varint_decode<std::size_t>(len_start, pos);
+ if (len > std::size_t(end - pos)) return end;
+ value = pos;
+ value_length = len;
+ pos += len;
+ }
+ return pos;
+}
+
+static std::uint8_t const * skip_unknown(
+ std::uint8_t const * pos, std::uint8_t const * end
+) {
+ if (pos != end) {
+ uint8_t tag = *pos;
+ if ((tag & 0x7) == 0) {
+ pos = varint_skip(pos, end);
+ pos = varint_skip(pos, end);
+ } else if ((tag & 0x7) == 2) {
+ pos = varint_skip(pos, end);
+ std::uint8_t const * len_start = pos;
+ pos = varint_skip(pos, end);
+ std::size_t len = varint_decode<std::size_t>(len_start, pos);
+ if (len > std::size_t(end - pos)) return end;
+ pos += len;
+ } else {
+ return end;
+ }
+ }
+ return pos;
+}
+
+} // namespace
+
+
+std::size_t olm::encode_message_length(
+ std::uint32_t counter,
+ std::size_t ratchet_key_length,
+ std::size_t ciphertext_length,
+ std::size_t mac_length
+) {
+ std::size_t length = VERSION_LENGTH;
+ length += 1 + varstring_length(ratchet_key_length);
+ length += 1 + varint_length(counter);
+ length += 1 + varstring_length(ciphertext_length);
+ length += mac_length;
+ return length;
+}
+
+
+void olm::encode_message(
+ olm::MessageWriter & writer,
+ std::uint8_t version,
+ std::uint32_t counter,
+ std::size_t ratchet_key_length,
+ std::size_t ciphertext_length,
+ std::uint8_t * output
+) {
+ std::uint8_t * pos = output;
+ *(pos++) = version;
+ pos = encode(pos, RATCHET_KEY_TAG, writer.ratchet_key, ratchet_key_length);
+ pos = encode(pos, COUNTER_TAG, counter);
+ pos = encode(pos, CIPHERTEXT_TAG, writer.ciphertext, ciphertext_length);
+}
+
+
+void olm::decode_message(
+ olm::MessageReader & reader,
+ std::uint8_t const * input, std::size_t input_length,
+ std::size_t mac_length
+) {
+ std::uint8_t const * pos = input;
+ std::uint8_t const * end = input + input_length - mac_length;
+ std::uint8_t const * unknown = nullptr;
+
+ reader.version = 0;
+ reader.has_counter = false;
+ reader.counter = 0;
+ reader.input = input;
+ reader.input_length = input_length;
+ reader.ratchet_key = nullptr;
+ reader.ratchet_key_length = 0;
+ reader.ciphertext = nullptr;
+ reader.ciphertext_length = 0;
+
+ if (input_length < mac_length) return;
+
+ if (pos == end) return;
+ reader.version = *(pos++);
+
+ while (pos != end) {
+ unknown = pos;
+ pos = decode(
+ pos, end, RATCHET_KEY_TAG,
+ reader.ratchet_key, reader.ratchet_key_length
+ );
+ pos = decode(
+ pos, end, COUNTER_TAG,
+ reader.counter, reader.has_counter
+ );
+ pos = decode(
+ pos, end, CIPHERTEXT_TAG,
+ reader.ciphertext, reader.ciphertext_length
+ );
+ if (unknown == pos) {
+ pos = skip_unknown(pos, end);
+ }
+ }
+}
+
+
+namespace {
+
+static std::uint8_t const ONE_TIME_KEY_ID_TAG = 012;
+static std::uint8_t const BASE_KEY_TAG = 022;
+static std::uint8_t const IDENTITY_KEY_TAG = 032;
+static std::uint8_t const MESSAGE_TAG = 042;
+
+} // namespace
+
+
+std::size_t olm::encode_one_time_key_message_length(
+ std::size_t one_time_key_length,
+ std::size_t identity_key_length,
+ std::size_t base_key_length,
+ std::size_t message_length
+) {
+ std::size_t length = VERSION_LENGTH;
+ length += 1 + varstring_length(one_time_key_length);
+ length += 1 + varstring_length(identity_key_length);
+ length += 1 + varstring_length(base_key_length);
+ length += 1 + varstring_length(message_length);
+ return length;
+}
+
+
+void olm::encode_one_time_key_message(
+ olm::PreKeyMessageWriter & writer,
+ std::uint8_t version,
+ std::size_t identity_key_length,
+ std::size_t base_key_length,
+ std::size_t one_time_key_length,
+ std::size_t message_length,
+ std::uint8_t * output
+) {
+ std::uint8_t * pos = output;
+ *(pos++) = version;
+ pos = encode(pos, ONE_TIME_KEY_ID_TAG, writer.one_time_key, one_time_key_length);
+ pos = encode(pos, BASE_KEY_TAG, writer.base_key, base_key_length);
+ pos = encode(pos, IDENTITY_KEY_TAG, writer.identity_key, identity_key_length);
+ pos = encode(pos, MESSAGE_TAG, writer.message, message_length);
+}
+
+
+void olm::decode_one_time_key_message(
+ PreKeyMessageReader & reader,
+ std::uint8_t const * input, std::size_t input_length
+) {
+ std::uint8_t const * pos = input;
+ std::uint8_t const * end = input + input_length;
+ std::uint8_t const * unknown = nullptr;
+
+ reader.version = 0;
+ reader.one_time_key = nullptr;
+ reader.one_time_key_length = 0;
+ reader.identity_key = nullptr;
+ reader.identity_key_length = 0;
+ reader.base_key = nullptr;
+ reader.base_key_length = 0;
+ reader.message = nullptr;
+ reader.message_length = 0;
+
+ if (pos == end) return;
+ reader.version = *(pos++);
+
+ while (pos != end) {
+ unknown = pos;
+ pos = decode(
+ pos, end, ONE_TIME_KEY_ID_TAG,
+ reader.one_time_key, reader.one_time_key_length
+ );
+ pos = decode(
+ pos, end, BASE_KEY_TAG,
+ reader.base_key, reader.base_key_length
+ );
+ pos = decode(
+ pos, end, IDENTITY_KEY_TAG,
+ reader.identity_key, reader.identity_key_length
+ );
+ pos = decode(
+ pos, end, MESSAGE_TAG,
+ reader.message, reader.message_length
+ );
+ if (unknown == pos) {
+ pos = skip_unknown(pos, end);
+ }
+ }
+}
+
+
+
+static const std::uint8_t GROUP_MESSAGE_INDEX_TAG = 010;
+static const std::uint8_t GROUP_CIPHERTEXT_TAG = 022;
+
+size_t _olm_encode_group_message_length(
+ uint32_t message_index,
+ size_t ciphertext_length,
+ size_t mac_length,
+ size_t signature_length
+) {
+ size_t length = VERSION_LENGTH;
+ length += 1 + varint_length(message_index);
+ length += 1 + varstring_length(ciphertext_length);
+ length += mac_length;
+ length += signature_length;
+ return length;
+}
+
+
+size_t _olm_encode_group_message(
+ uint8_t version,
+ uint32_t message_index,
+ size_t ciphertext_length,
+ uint8_t *output,
+ uint8_t **ciphertext_ptr
+) {
+ std::uint8_t * pos = output;
+
+ *(pos++) = version;
+ pos = encode(pos, GROUP_MESSAGE_INDEX_TAG, message_index);
+ pos = encode(pos, GROUP_CIPHERTEXT_TAG, *ciphertext_ptr, ciphertext_length);
+ return pos-output;
+}
+
+void _olm_decode_group_message(
+ const uint8_t *input, size_t input_length,
+ size_t mac_length, size_t signature_length,
+ struct _OlmDecodeGroupMessageResults *results
+) {
+ std::uint8_t const * pos = input;
+ std::size_t trailer_length = mac_length + signature_length;
+ std::uint8_t const * end = input + input_length - trailer_length;
+ std::uint8_t const * unknown = nullptr;
+
+ bool has_message_index = false;
+ results->version = 0;
+ results->message_index = 0;
+ results->has_message_index = (int)has_message_index;
+ results->ciphertext = nullptr;
+ results->ciphertext_length = 0;
+
+ if (input_length < trailer_length) return;
+
+ if (pos == end) return;
+ results->version = *(pos++);
+
+ while (pos != end) {
+ unknown = pos;
+ pos = decode(
+ pos, end, GROUP_MESSAGE_INDEX_TAG,
+ results->message_index, has_message_index
+ );
+ pos = decode(
+ pos, end, GROUP_CIPHERTEXT_TAG,
+ results->ciphertext, results->ciphertext_length
+ );
+ if (unknown == pos) {
+ pos = skip_unknown(pos, end);
+ }
+ }
+
+ results->has_message_index = (int)has_message_index;
+}
projects / matrix_esp_thesis / blobdiff