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feat: Remove custom protobuf parsing

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This commit is contained in:
PapaTutuWawa
2023-06-12 23:39:08 +02:00
parent 0ffc0b067a
commit 50f6513c6f
12 changed files with 53 additions and 1454 deletions
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15
lib/src/double_ratchet/crypto.dart
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@@ -1,8 +1,7 @@
import 'package:omemo_dart/protobuf/schema.pb.dart';
import 'package:omemo_dart/src/crypto.dart';
import 'package:omemo_dart/src/errors.dart';
import 'package:omemo_dart/src/helpers.dart';
import 'package:omemo_dart/src/protobuf/omemo_authenticated_message.dart';
import 'package:omemo_dart/src/protobuf/omemo_message.dart';
/// Info string for ENCRYPT
const encryptHkdfInfoString = 'OMEMO Message Key Material';
@@ -22,12 +21,12 @@ Future<List<int>> encrypt(
await aes256CbcEncrypt(plaintext, keys.encryptionKey, keys.iv);
final header =
OmemoMessage.fromBuffer(associatedData.sublist(sessionAd.length))
OMEMOMessage.fromBuffer(associatedData.sublist(sessionAd.length))
..ciphertext = ciphertext;
final headerBytes = header.writeToBuffer();
final hmacInput = concat([sessionAd, headerBytes]);
final hmacResult = await truncatedHmac(hmacInput, keys.authenticationKey);
final message = OmemoAuthenticatedMessage()
final message = OMEMOAuthenticatedMessage()
..mac = hmacResult
..message = headerBytes;
return message.writeToBuffer();
@@ -46,15 +45,15 @@ Future<List<int>> decrypt(
final keys = await deriveEncryptionKeys(mk, encryptHkdfInfoString);
// Assumption ciphertext is a OMEMOAuthenticatedMessage
final message = OmemoAuthenticatedMessage.fromBuffer(ciphertext);
final header = OmemoMessage.fromBuffer(message.message!);
final message = OMEMOAuthenticatedMessage.fromBuffer(ciphertext);
final header = OMEMOMessage.fromBuffer(message.message);
final hmacInput = concat([sessionAd, header.writeToBuffer()]);
final hmacResult = await truncatedHmac(hmacInput, keys.authenticationKey);
if (!listsEqual(hmacResult, message.mac!)) {
if (!listsEqual(hmacResult, message.mac)) {
throw InvalidMessageHMACException();
}
return aes256CbcDecrypt(header.ciphertext!, keys.encryptionKey, keys.iv);
return aes256CbcDecrypt(header.ciphertext, keys.encryptionKey, keys.iv);
}

24
lib/src/double_ratchet/double_ratchet.dart
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@@ -2,20 +2,20 @@ import 'dart:convert';
import 'package:cryptography/cryptography.dart';
import 'package:hex/hex.dart';
import 'package:meta/meta.dart';
import 'package:omemo_dart/protobuf/schema.pb.dart';
import 'package:omemo_dart/src/crypto.dart';
import 'package:omemo_dart/src/double_ratchet/crypto.dart';
import 'package:omemo_dart/src/double_ratchet/kdf.dart';
import 'package:omemo_dart/src/errors.dart';
import 'package:omemo_dart/src/helpers.dart';
import 'package:omemo_dart/src/keys.dart';
import 'package:omemo_dart/src/protobuf/omemo_message.dart';
/// Amount of messages we may skip per session
const maxSkip = 1000;
class RatchetStep {
const RatchetStep(this.header, this.ciphertext);
final OmemoMessage header;
final OMEMOMessage header;
final List<int> ciphertext;
}
@@ -274,12 +274,12 @@ class OmemoDoubleRatchet {
}
Future<List<int>?> _trySkippedMessageKeys(
OmemoMessage header,
OMEMOMessage header,
List<int> ciphertext,
) async {
final key = SkippedKey(
OmemoPublicKey.fromBytes(header.dhPub!, KeyPairType.x25519),
header.n!,
OmemoPublicKey.fromBytes(header.dhPub, KeyPairType.x25519),
header.n,
);
if (mkSkipped.containsKey(key)) {
final mk = mkSkipped[key]!;
@@ -312,11 +312,11 @@ class OmemoDoubleRatchet {
}
}
Future<void> _dhRatchet(OmemoMessage header) async {
Future<void> _dhRatchet(OMEMOMessage header) async {
pn = ns;
ns = 0;
nr = 0;
dhr = OmemoPublicKey.fromBytes(header.dhPub!, KeyPairType.x25519);
dhr = OmemoPublicKey.fromBytes(header.dhPub, KeyPairType.x25519);
final newRk = await kdfRk(rk, await omemoDH(dhs, dhr!, 0));
rk = List.from(newRk);
@@ -333,7 +333,7 @@ class OmemoDoubleRatchet {
final mk = await kdfCk(cks!, kdfCkNextMessageKey);
cks = newCks;
final header = OmemoMessage()
final header = OMEMOMessage()
..dhPub = await dhs.pk.getBytes()
..pn = pn
..n = ns;
@@ -356,7 +356,7 @@ class OmemoDoubleRatchet {
///
/// Throws an SkippingTooManyMessagesException if too many messages were to be skipped.
Future<List<int>> ratchetDecrypt(
OmemoMessage header,
OMEMOMessage header,
List<int> ciphertext,
) async {
// Check if we skipped too many messages
@@ -366,15 +366,15 @@ class OmemoDoubleRatchet {
}
final dhPubMatches = listsEqual(
header.dhPub!,
header.dhPub,
(await dhr?.getBytes()) ?? <int>[],
);
if (!dhPubMatches) {
await _skipMessageKeys(header.pn!);
await _skipMessageKeys(header.pn);
await _dhRatchet(header);
}
await _skipMessageKeys(header.n!);
await _skipMessageKeys(header.n);
final newCkr = await kdfCk(ckr!, kdfCkNextChainKey);
final mk = await kdfCk(ckr!, kdfCkNextMessageKey);
ckr = newCkr;

44
lib/src/omemo/omemomanager.dart
View File

@@ -6,6 +6,7 @@ import 'package:cryptography/cryptography.dart';
import 'package:hex/hex.dart';
import 'package:logging/logging.dart';
import 'package:meta/meta.dart';
import 'package:omemo_dart/protobuf/schema.pb.dart';
import 'package:omemo_dart/src/crypto.dart';
import 'package:omemo_dart/src/double_ratchet/double_ratchet.dart';
import 'package:omemo_dart/src/errors.dart';
@@ -21,9 +22,6 @@ import 'package:omemo_dart/src/omemo/events.dart';
import 'package:omemo_dart/src/omemo/fingerprint.dart';
import 'package:omemo_dart/src/omemo/ratchet_map_key.dart';
import 'package:omemo_dart/src/omemo/stanza.dart';
import 'package:omemo_dart/src/protobuf/omemo_authenticated_message.dart';
import 'package:omemo_dart/src/protobuf/omemo_key_exchange.dart';
import 'package:omemo_dart/src/protobuf/omemo_message.dart';
import 'package:omemo_dart/src/trust/base.dart';
import 'package:omemo_dart/src/x3dh/x3dh.dart';
import 'package:synchronized/synchronized.dart';
@@ -194,7 +192,7 @@ class OmemoManager {
Future<OmemoDoubleRatchet> _addSessionFromKeyExchange(
String jid,
int deviceId,
OmemoKeyExchange kex,
OMEMOKeyExchange kex,
) async {
// Pick the correct SPK
final device = await getDevice();
@@ -209,17 +207,17 @@ class OmemoManager {
final kexResult = await x3dhFromInitialMessage(
X3DHMessage(
OmemoPublicKey.fromBytes(kex.ik!, KeyPairType.ed25519),
OmemoPublicKey.fromBytes(kex.ek!, KeyPairType.x25519),
kex.pkId!,
OmemoPublicKey.fromBytes(kex.ik, KeyPairType.ed25519),
OmemoPublicKey.fromBytes(kex.ek, KeyPairType.x25519),
kex.pkId,
),
spk,
device.opks.values.elementAt(kex.pkId!),
device.opks.values.elementAt(kex.pkId),
device.ik,
);
final ratchet = await OmemoDoubleRatchet.acceptNewSession(
spk,
OmemoPublicKey.fromBytes(kex.ik!, KeyPairType.ed25519),
OmemoPublicKey.fromBytes(kex.ik, KeyPairType.ed25519),
kexResult.sk,
kexResult.ad,
getTimestamp(),
@@ -234,7 +232,7 @@ class OmemoManager {
/// Create a ratchet session initiated by Alice to the user with Jid [jid] and the device
/// [deviceId] from the bundle [bundle].
@visibleForTesting
Future<OmemoKeyExchange> addSessionFromBundle(
Future<OMEMOKeyExchange> addSessionFromBundle(
String jid,
int deviceId,
OmemoBundle bundle,
@@ -255,7 +253,7 @@ class OmemoManager {
await _trustManager.onNewSession(jid, deviceId);
_addSession(jid, deviceId, ratchet);
return OmemoKeyExchange()
return OMEMOKeyExchange()
..pkId = kexResult.opkId
..spkId = bundle.spkId
..ik = await device.ik.pk.getBytes()
@@ -312,17 +310,17 @@ class OmemoManager {
final decodedRawKey = base64.decode(rawKey.value);
List<int>? keyAndHmac;
OmemoAuthenticatedMessage authMessage;
OmemoMessage? message;
OMEMOAuthenticatedMessage authMessage;
OMEMOMessage? message;
// If the ratchet already existed, we store it. If it didn't, oldRatchet will stay
// null.
final ratchetKey = RatchetMapKey(senderJid, senderDeviceId);
final oldRatchet = getRatchet(ratchetKey)?.clone();
if (rawKey.kex) {
final kex = OmemoKeyExchange.fromBuffer(decodedRawKey);
authMessage = kex.message!;
message = OmemoMessage.fromBuffer(authMessage.message!);
final kex = OMEMOKeyExchange.fromBuffer(decodedRawKey);
authMessage = kex.message;
message = OMEMOMessage.fromBuffer(authMessage.message);
// Guard against old key exchanges
if (oldRatchet != null) {
@@ -348,7 +346,7 @@ class OmemoManager {
// Replace the OPK
await _deviceLock.synchronized(() async {
device = await device.replaceOnetimePrekey(kex.pkId!);
device = await device.replaceOnetimePrekey(kex.pkId);
// Commit the device
_eventStreamController.add(DeviceModifiedEvent(device));
@@ -374,8 +372,8 @@ class OmemoManager {
_log.finest('Kex failed due to $ex. Not proceeding with kex.');
}
} else {
authMessage = OmemoAuthenticatedMessage.fromBuffer(decodedRawKey);
message = OmemoMessage.fromBuffer(authMessage.message!);
authMessage = OMEMOAuthenticatedMessage.fromBuffer(decodedRawKey);
message = OMEMOMessage.fromBuffer(authMessage.message);
}
final devices = _deviceList[senderJid];
@@ -499,7 +497,7 @@ class OmemoManager {
keyPayload = List<int>.filled(32, 0x0);
}
final kex = <RatchetMapKey, OmemoKeyExchange>{};
final kex = <RatchetMapKey, OMEMOKeyExchange>{};
for (final jid in jids) {
for (final newSession in await _fetchNewBundles(jid)) {
kex[RatchetMapKey(jid, newSession.id)] = await addSessionFromBundle(
@@ -551,7 +549,7 @@ class OmemoManager {
if (kex.containsKey(ratchetKey)) {
// The ratchet did not exist
final k = kex[ratchetKey]!
..message = OmemoAuthenticatedMessage.fromBuffer(ciphertext);
..message = OMEMOAuthenticatedMessage.fromBuffer(ciphertext);
final buffer = base64.encode(k.writeToBuffer());
encryptedKeys.add(
EncryptedKey(
@@ -568,8 +566,8 @@ class OmemoManager {
// The ratchet exists but is not acked
if (ratchet.kex != null) {
final oldKex =
OmemoKeyExchange.fromBuffer(base64.decode(ratchet.kex!))
..message = OmemoAuthenticatedMessage.fromBuffer(ciphertext);
OMEMOKeyExchange.fromBuffer(base64.decode(ratchet.kex!))
..message = OMEMOAuthenticatedMessage.fromBuffer(ciphertext);
encryptedKeys.add(
EncryptedKey(

38
lib/src/protobuf/omemo_authenticated_message.dart
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@@ -1,38 +0,0 @@
import 'package:omemo_dart/src/helpers.dart';
import 'package:omemo_dart/src/protobuf/protobuf.dart';
class OmemoAuthenticatedMessage {
OmemoAuthenticatedMessage();
factory OmemoAuthenticatedMessage.fromBuffer(List<int> data) {
var i = 0;
// required bytes mac = 1;
if (data[0] != fieldId(1, fieldTypeByteArray)) {
throw Exception();
}
final mac = data.sublist(2, i + 2 + data[1]);
i += data[1] + 2;
if (data[i] != fieldId(2, fieldTypeByteArray)) {
throw Exception();
}
final message = data.sublist(i + 2, i + 2 + data[i + 1]);
return OmemoAuthenticatedMessage()
..mac = mac
..message = message;
}
List<int>? mac;
List<int>? message;
List<int> writeToBuffer() {
return concat([
[fieldId(1, fieldTypeByteArray), mac!.length],
mac!,
[fieldId(2, fieldTypeByteArray), message!.length],
message!,
]);
}
}

71
lib/src/protobuf/omemo_key_exchange.dart
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@@ -1,71 +0,0 @@
import 'package:omemo_dart/src/helpers.dart';
import 'package:omemo_dart/src/protobuf/omemo_authenticated_message.dart';
import 'package:omemo_dart/src/protobuf/protobuf.dart';
class OmemoKeyExchange {
OmemoKeyExchange();
factory OmemoKeyExchange.fromBuffer(List<int> data) {
var i = 0;
if (data[i] != fieldId(1, fieldTypeUint32)) {
throw Exception();
}
var decoded = decodeVarint(data, 1);
final pkId = decoded.n;
i += decoded.length + 1;
if (data[i] != fieldId(2, fieldTypeUint32)) {
throw Exception();
}
decoded = decodeVarint(data, i + 1);
final spkId = decoded.n;
i += decoded.length + 1;
if (data[i] != fieldId(3, fieldTypeByteArray)) {
throw Exception();
}
final ik = data.sublist(i + 2, i + 2 + data[i + 1]);
i += 2 + data[i + 1];
if (data[i] != fieldId(4, fieldTypeByteArray)) {
throw Exception();
}
final ek = data.sublist(i + 2, i + 2 + data[i + 1]);
i += 2 + data[i + 1];
if (data[i] != fieldId(5, fieldTypeByteArray)) {
throw Exception();
}
final message = OmemoAuthenticatedMessage.fromBuffer(data.sublist(i + 2));
return OmemoKeyExchange()
..pkId = pkId
..spkId = spkId
..ik = ik
..ek = ek
..message = message;
}
int? pkId;
int? spkId;
List<int>? ik;
List<int>? ek;
OmemoAuthenticatedMessage? message;
List<int> writeToBuffer() {
final msg = message!.writeToBuffer();
return concat([
[fieldId(1, fieldTypeUint32)],
encodeVarint(pkId!),
[fieldId(2, fieldTypeUint32)],
encodeVarint(spkId!),
[fieldId(3, fieldTypeByteArray), ik!.length],
ik!,
[fieldId(4, fieldTypeByteArray), ek!.length],
ek!,
[fieldId(5, fieldTypeByteArray), msg.length],
msg,
]);
}
}

75
lib/src/protobuf/omemo_message.dart
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@@ -1,75 +0,0 @@
import 'package:omemo_dart/src/helpers.dart';
import 'package:omemo_dart/src/protobuf/protobuf.dart';
class OmemoMessage {
OmemoMessage();
factory OmemoMessage.fromBuffer(List<int> data) {
var i = 0;
// required uint32 n = 1;
if (data[0] != fieldId(1, fieldTypeUint32)) {
throw Exception();
}
var decode = decodeVarint(data, 1);
final n = decode.n;
i += decode.length + 1;
// required uint32 pn = 2;
if (data[i] != fieldId(2, fieldTypeUint32)) {
throw Exception();
}
decode = decodeVarint(data, i + 1);
final pn = decode.n;
i += decode.length + 1;
// required bytes dh_pub = 3;
if (data[i] != fieldId(3, fieldTypeByteArray)) {
throw Exception();
}
final dhPub = data.sublist(i + 2, i + 2 + data[i + 1]);
i += 2 + data[i + 1];
// optional bytes ciphertext = 4;
List<int>? ciphertext;
if (i < data.length) {
if (data[i] != fieldId(4, fieldTypeByteArray)) {
throw Exception();
}
ciphertext = data.sublist(i + 2, i + 2 + data[i + 1]);
}
return OmemoMessage()
..n = n
..pn = pn
..dhPub = dhPub
..ciphertext = ciphertext;
}
int? n;
int? pn;
List<int>? dhPub;
List<int>? ciphertext;
List<int> writeToBuffer() {
final data = concat([
[fieldId(1, fieldTypeUint32)],
encodeVarint(n!),
[fieldId(2, fieldTypeUint32)],
encodeVarint(pn!),
[fieldId(3, fieldTypeByteArray), dhPub!.length],
dhPub!,
]);
if (ciphertext != null) {
return concat([
data,
[fieldId(4, fieldTypeByteArray), ciphertext!.length],
ciphertext!,
]);
}
return data;
}
}

64
lib/src/protobuf/protobuf.dart
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@@ -1,64 +0,0 @@
/// Masks the 7 LSB
const lsb7Mask = 0x7F;
/// Constant for setting the MSB
const msb = 1 << 7;
/// Field types
const fieldTypeUint32 = 0;
const fieldTypeByteArray = 2;
int fieldId(int number, int type) {
return (number << 3) | type;
}
class VarintDecode {
const VarintDecode(this.n, this.length);
final int n;
final int length;
}
/// Decode a Varint that begins at [input]'s index [offset].
VarintDecode decodeVarint(List<int> input, int offset) {
// The return value
var n = 0;
// The byte offset counter
var i = 0;
// Iterate until the MSB of the byte is 0
while (true) {
// Mask only the 7 LSB and "move" them accordingly
n += (input[offset + i] & lsb7Mask) << (7 * i);
// Break if we reached the end
if (input[offset + i] & 1 << 7 == 0) {
break;
}
i++;
}
return VarintDecode(n, i + 1);
}
// Encodes the integer [i] into a Varint.
List<int> encodeVarint(int i) {
assert(i >= 0, "Two's complement is not implemented");
final ret = List<int>.empty(growable: true);
// Thanks to https://github.com/hathibelagal-dev/LEB128 for the trick with toRadixString!
final numSevenBlocks = (i.toRadixString(2).length / 7).ceil();
for (var j = 0; j < numSevenBlocks; j++) {
// The 7 LSB of the byte we're creating
final x = (i & (lsb7Mask << j * 7)) >> j * 7;
if (j == numSevenBlocks - 1) {
// If we were to shift further, we only get zero, so we're at the end
ret.add(x);
} else {
// We still have at least one bit more to go, so set the MSB to 1
ret.add(x + msb);
}
}
return ret;
}