Change the JSON format for one time keys to include what algorithm they are for

4 files changed, 85 insertions, 78 deletions

diff --git a/src/account.cpp b/src/account.cpp
index 297d2f4..a171f5c 100644
--- a/src/account.cpp
+++ b/src/account.cpp
@@ -143,13 +143,17 @@ std::size_t olm::Account::get_identity_json_length(
     length += sizeof(IDENTITY_JSON_PART_0) - 1;
     length += device_id_length;
     length += sizeof(IDENTITY_JSON_PART_1) - 1;
-    length += 4;
+    length += olm::encode_base64_length(3);
     length += sizeof(IDENTITY_JSON_PART_2) - 1;
-    length += 43;
+    length += olm::encode_base64_length(
+        sizeof(identity_keys.curve25519_key.public_key)
+    );
     length += sizeof(IDENTITY_JSON_PART_3) - 1;
-    length += 4;
+    length += olm::encode_base64_length(3);
     length += sizeof(IDENTITY_JSON_PART_4) - 1;
-    length += 43;
+    length += olm::encode_base64_length(
+        sizeof(identity_keys.ed25519_key.public_key)
+    );
     length += sizeof(IDENTITY_JSON_PART_5) - 1;
     length += user_id_length;
     length += sizeof(IDENTITY_JSON_PART_6) - 1;
@@ -161,9 +165,9 @@ std::size_t olm::Account::get_identity_json_length(
     length += sizeof(IDENTITY_JSON_PART_9) - 1;
     length += device_id_length;
     length += sizeof(IDENTITY_JSON_PART_A) - 1;
-    length += 4;
+    length += olm::encode_base64_length(3);
     length += sizeof(IDENTITY_JSON_PART_B) - 1;
-    length += 86;
+    length += olm::encode_base64_length(64);
     length += sizeof(IDENTITY_JSON_PART_C) - 1;
     return length;
 }
@@ -176,7 +180,6 @@ std::size_t olm::Account::get_identity_json(
     std::uint64_t valid_until_ts,
     std::uint8_t * identity_json, std::size_t identity_json_length
 ) {
-
     std::uint8_t * pos = identity_json;
     std::uint8_t signature[64];
     size_t expected_length = get_identity_json_length(
@@ -191,17 +194,13 @@ std::size_t olm::Account::get_identity_json(
     pos = write_string(pos, IDENTITY_JSON_PART_0);
     pos = write_string(pos, device_id, device_id_length);
     pos = write_string(pos, IDENTITY_JSON_PART_1);
-    encode_base64(identity_keys.curve25519_key.public_key, 3, pos);
-    pos += 4;
+    pos = encode_base64(identity_keys.curve25519_key.public_key, 3, pos);
     pos = write_string(pos, IDENTITY_JSON_PART_2);
-    encode_base64(identity_keys.curve25519_key.public_key, 32, pos);
-    pos += 43;
+    pos = encode_base64(identity_keys.curve25519_key.public_key, 32, pos);
     pos = write_string(pos, IDENTITY_JSON_PART_3);
-    encode_base64(identity_keys.ed25519_key.public_key, 3, pos);
-    pos += 4;
+    pos = encode_base64(identity_keys.ed25519_key.public_key, 3, pos);
     pos = write_string(pos, IDENTITY_JSON_PART_4);
-    encode_base64(identity_keys.ed25519_key.public_key, 32, pos);
-    pos += 43;
+    pos = encode_base64(identity_keys.ed25519_key.public_key, 32, pos);
     pos = write_string(pos, IDENTITY_JSON_PART_5);
     pos = write_string(pos, user_id, user_id_length);
     pos = write_string(pos, IDENTITY_JSON_PART_6);
@@ -221,15 +220,69 @@ std::size_t olm::Account::get_identity_json(
     pos = write_string(pos, IDENTITY_JSON_PART_9);
     pos = write_string(pos, device_id, device_id_length);
     pos = write_string(pos, IDENTITY_JSON_PART_A);
-    encode_base64(identity_keys.ed25519_key.public_key, 3, pos);
-    pos += 4;
+    pos = encode_base64(identity_keys.ed25519_key.public_key, 3, pos);
     pos = write_string(pos, IDENTITY_JSON_PART_B);
-    encode_base64(signature, 64, pos);
-    pos += 86;
+    pos = encode_base64(signature, 64, pos);
     pos = write_string(pos, IDENTITY_JSON_PART_C);
     return pos - identity_json;
 }
 
+namespace {
+uint8_t ONE_TIME_KEY_JSON_ALG[] = "curve25519";
+}
+
+std::size_t olm::Account::get_one_time_keys_json_length(
+) {
+    std::size_t length = 0;
+    for (auto const & key : one_time_keys) {
+        length += 2; /* {" */
+        length += sizeof(ONE_TIME_KEY_JSON_ALG) - 1;
+        length += 1; /* : */
+        length += olm::encode_base64_length(olm::pickle_length(key.id));
+        length += 3; /* ":" */
+        length += olm::encode_base64_length(sizeof(key.key.public_key));
+        length += 1; /* " */
+    }
+    if (length) {
+        return length + 1; /* } */
+    } else {
+        return 2; /* {} */
+    }
+}
+
+
+std::size_t olm::Account::get_one_time_keys_json(
+    std::uint8_t * one_time_json, std::size_t one_time_json_length
+) {
+    std::uint8_t * pos = one_time_json;
+    if (one_time_json_length < get_one_time_keys_json_length()) {
+        last_error = olm::ErrorCode::OUTPUT_BUFFER_TOO_SMALL;
+        return std::size_t(-1);
+    }
+    std::uint8_t sep = '{';
+    for (auto const & key : one_time_keys) {
+        *(pos++) = sep;
+        *(pos++) = '\"';
+        pos = write_string(pos, ONE_TIME_KEY_JSON_ALG);
+        *(pos++) = ':';
+        std::uint8_t key_id[olm::pickle_length(key.id)];
+        olm::pickle(key_id, key.id);
+        pos = olm::encode_base64(key_id, sizeof(key_id), pos);
+        *(pos++) = '\"'; *(pos++) = ':'; *(pos++) = '\"';
+        pos = olm::encode_base64(
+            key.key.public_key, sizeof(key.key.public_key), pos
+        );
+        *(pos++) = '\"';
+        sep = ',';
+    }
+    if (sep != ',') {
+        *(pos++) = sep;
+    }
+    *(pos++) = '}';
+    return pos - one_time_json;
+}
+
+
 namespace olm {
 
 static std::size_t pickle_length(
diff --git a/src/base64.cpp b/src/base64.cpp
index a8631a1..bf8492e 100644
--- a/src/base64.cpp
+++ b/src/base64.cpp
@@ -45,14 +45,7 @@ static const std::uint8_t DECODE_BASE64[128] = {
 } // namespace
 
 
-std::size_t olm::encode_base64_length(
-    std::size_t input_length
-) {
-    return 4 * ((input_length + 2) / 3) + (input_length + 2) % 3 - 2;
-}
-
-
-void olm::encode_base64(
+std::uint8_t * olm::encode_base64(
     std::uint8_t const * input, std::size_t input_length,
     std::uint8_t * output
 ) {
@@ -70,6 +63,7 @@ void olm::encode_base64(
         output += 4;
     }
     unsigned remainder = input + input_length - pos;
+    std::uint8_t * result = output;
     if (remainder) {
         unsigned value = pos[0];
         if (remainder == 2) {
@@ -77,13 +71,16 @@ void olm::encode_base64(
             value <<= 2;
             output[2] = ENCODE_BASE64[value & 0x3F];
             value >>= 6;
+            result += 3;
         } else {
             value <<= 4;
+            result += 2;
         }
         output[1] = ENCODE_BASE64[value & 0x3F];
         value >>= 6;
         output[0] = ENCODE_BASE64[value];
     }
+    return result;
 }
 
 
@@ -98,7 +95,7 @@ std::size_t olm::decode_base64_length(
 }
 
 
-void olm::decode_base64(
+std::uint8_t const * olm::decode_base64(
     std::uint8_t const * input, std::size_t input_length,
     std::uint8_t * output
 ) {
@@ -129,4 +126,5 @@ void olm::decode_base64(
         }
         output[0] = value;
     }
+    return input + input_length;
 }
diff --git a/src/olm.cpp b/src/olm.cpp
index 8106917..ede9c26 100644
--- a/src/olm.cpp
+++ b/src/olm.cpp
@@ -320,38 +320,6 @@ size_t olm_create_account(
     return from_c(account)->new_account(from_c(random), random_length);
 }
 
-namespace {
-
-static const std::size_t OUTPUT_KEY_LENGTH = 2 + 10 + 2 +
-        olm::encode_base64_length(32) + 3;
-
-void output_one_time_key(
-    olm::OneTimeKey const & key,
-    std::uint8_t sep,
-    std::uint8_t * output
-) {
-    output[0] = sep;
-    output[1] = '[';
-    std::memset(output + 2, ' ', 10);
-    uint32_t value = key.id;
-    uint8_t * number = output + 11;
-    *number = '0' + value % 10;
-    value /= 10;
-    while (value) {
-        *(--number) = '0' + value % 10;
-        value /= 10;
-    }
-    output[12] = ',';
-    output[13] = '"';
-    olm::encode_base64(key.key.public_key, 32, output + 14);
-    output[OUTPUT_KEY_LENGTH - 3] = '"';
-    output[OUTPUT_KEY_LENGTH - 2] = ']';
-    output[OUTPUT_KEY_LENGTH - 1] = '\n';
-}
-
-} // namespace
-
-
 size_t olm_account_identity_keys_length(
     OlmAccount * account,
     size_t user_id_length,
@@ -388,30 +356,17 @@ size_t olm_account_identity_keys(
 size_t olm_account_one_time_keys_length(
     OlmAccount * account
 ) {
-    size_t count = from_c(account)->one_time_keys.size();
-    return OUTPUT_KEY_LENGTH * count + 1;
+    return from_c(account)->get_one_time_keys_json_length();
 }
 
 
 size_t olm_account_one_time_keys(
     OlmAccount * account,
-    void * identity_keys, size_t identity_key_length
+    void * one_time_keys_json, size_t one_time_key_json_length
 ) {
-    std::size_t length = olm_account_one_time_keys_length(account);
-    if (identity_key_length < length) {
-        from_c(account)->last_error =
-            olm::ErrorCode::OUTPUT_BUFFER_TOO_SMALL;
-        return size_t(-1);
-    }
-    std::uint8_t * output = from_c(identity_keys);
-    std::uint8_t sep = '[';
-    for (auto const & key : from_c(account)->one_time_keys) {
-        output_one_time_key(key, sep, output);
-        output += OUTPUT_KEY_LENGTH;
-        sep = ',';
-    }
-    output[0] = ']';
-    return length;
+    return from_c(account)->get_one_time_keys_json(
+        from_c(one_time_keys_json), one_time_key_json_length
+    );
 }
 
 
diff --git a/src/session.cpp b/src/session.cpp
index a56725d..f3b7637 100644
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -157,6 +157,7 @@ std::size_t olm::Session::new_inbound_session(
         last_error = olm::ErrorCode::BAD_MESSAGE_KEY_ID;
         return std::size_t(-1);
     }
+    bob_one_time_key_id = our_one_time_key->id;
 
     std::uint8_t shared_secret[96];