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Some improvements in mtproto data processing.

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Readability improvements. Checking maximum padding size.
Checking SHA1 hash before validating inner message length.
This commit is contained in:
John Preston 2017-02-27 12:51:03 +03:00
parent 4838d1bfc9
commit 6c2f16e9a0
5 changed files with 74 additions and 63 deletions
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139
Telegram/SourceFiles/mtproto/connection.cpp
View file

@ -43,6 +43,7 @@ namespace internal {
namespace {
constexpr auto kRecreateKeyId = AuthKey::KeyId(0xFFFFFFFFFFFFFFFFULL);
constexpr auto kIntSize = static_cast<int>(sizeof(mtpPrime));
void wrapInvokeAfter(mtpRequest &to, const mtpRequest &from, const mtpRequestMap &haveSent, int32 skipBeforeRequest = 0) {
mtpMsgId afterId(*(mtpMsgId*)(from->after->data() + 4));
@ -1314,92 +1315,101 @@ void ConnectionPrivate::handleReceived() {
onReceivedSome();
auto restartOnError = [this, &lockFinished] {
lockFinished.unlock();
restart();
};
ReadLockerAttempt lock(sessionData->keyMutex());
if (!lock) {
DEBUG_LOG(("MTP Error: auth_key for dc %1 busy, cant lock").arg(_shiftedDcId));
clearMessages();
keyId = 0;
lockFinished.unlock();
return restart();
return restartOnError();
}
auto key = sessionData->getKey();
if (!key || key->keyId() != keyId) {
DEBUG_LOG(("MTP Error: auth_key id for dc %1 changed").arg(_shiftedDcId));
lockFinished.unlock();
return restart();
return restartOnError();
}
while (_conn->received().size()) {
const mtpBuffer &encryptedBuf(_conn->received().front());
uint32 len = encryptedBuf.size();
const mtpPrime *encrypted(encryptedBuf.data());
if (len < 18) { // 2 auth_key_id, 4 msg_key, 2 salt, 2 session, 2 msg_id, 1 seq_no, 1 length, (1 data + 3 padding) min
LOG(("TCP Error: bad message received, len %1").arg(len * sizeof(mtpPrime)));
TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encrypted, len * sizeof(mtpPrime)).str()));
lockFinished.unlock();
return restart();
}
if (keyId != *(uint64*)encrypted) {
LOG(("TCP Error: bad auth_key_id %1 instead of %2 received").arg(keyId).arg(*(uint64*)encrypted));
TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encrypted, len * sizeof(mtpPrime)).str()));
lockFinished.unlock();
return restart();
}
QByteArray dataBuffer((len - 6) * sizeof(mtpPrime), Qt::Uninitialized);
mtpPrime *data((mtpPrime*)dataBuffer.data()), *msg = data + 8;
const mtpPrime *from(msg), *end;
MTPint128 msgKey(*(MTPint128*)(encrypted + 2));
aesIgeDecrypt(encrypted + 6, data, dataBuffer.size(), key, msgKey);
uint64 serverSalt = *(uint64*)&data[0], session = *(uint64*)&data[2], msgId = *(uint64*)&data[4];
uint32 seqNo = *(uint32*)&data[6], msgLen = *(uint32*)&data[7];
bool needAck = (seqNo & 0x01);
if (uint32(dataBuffer.size()) < msgLen + 8 * sizeof(mtpPrime) || (msgLen & 0x03)) {
LOG(("TCP Error: bad msg_len received %1, data size: %2").arg(msgLen).arg(dataBuffer.size()));
TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encrypted, len * sizeof(mtpPrime)).str()));
while (!_conn->received().empty()) {
auto intsBuffer = std::move(_conn->received().front());
_conn->received().pop_front();
lockFinished.unlock();
return restart();
}
uchar sha1Buffer[20];
if (memcmp(&msgKey, hashSha1(data, msgLen + 8 * sizeof(mtpPrime), sha1Buffer) + 1, sizeof(msgKey))) {
LOG(("TCP Error: bad SHA1 hash after aesDecrypt in message"));
TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encrypted, len * sizeof(mtpPrime)).str()));
_conn->received().pop_front();
constexpr auto kExternalHeaderIntsCount = 6U; // 2 auth_key_id, 4 msg_key
constexpr auto kEncryptedHeaderIntsCount = 8U; // 2 salt, 2 session, 2 msg_id, 1 seq_no, 1 length
constexpr auto kMinimalEncryptedIntsCount = kEncryptedHeaderIntsCount + 4U; // + 1 data + 3 padding
constexpr auto kMinimalIntsCount = kExternalHeaderIntsCount + kMinimalEncryptedIntsCount;
auto intsCount = uint32(intsBuffer.size());
auto ints = intsBuffer.constData();
if (intsCount < kMinimalIntsCount) {
LOG(("TCP Error: bad message received, len %1").arg(intsCount * kIntSize));
TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(ints, intsCount * kIntSize).str()));
lockFinished.unlock();
return restart();
return restartOnError();
}
TCP_LOG(("TCP Info: decrypted message %1,%2,%3 is %4 len").arg(msgId).arg(seqNo).arg(Logs::b(needAck)).arg(msgLen + 8 * sizeof(mtpPrime)));
if (keyId != *(uint64*)ints) {
LOG(("TCP Error: bad auth_key_id %1 instead of %2 received").arg(keyId).arg(*(uint64*)ints));
TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(ints, intsCount * kIntSize).str()));
return restartOnError();
}
auto encryptedInts = ints + kExternalHeaderIntsCount;
auto encryptedIntsCount = (intsCount - kExternalHeaderIntsCount);
auto encryptedBytesCount = encryptedIntsCount * kIntSize;
auto decryptedBuffer = QByteArray(encryptedBytesCount, Qt::Uninitialized);
auto msgKey = *(MTPint128*)(ints + 2);
aesIgeDecrypt(encryptedInts, decryptedBuffer.data(), encryptedBytesCount, key, msgKey);
auto decryptedInts = reinterpret_cast<const mtpPrime*>(decryptedBuffer.constData());
auto serverSalt = *(uint64*)&decryptedInts[0];
auto session = *(uint64*)&decryptedInts[2];
auto msgId = *(uint64*)&decryptedInts[4];
auto seqNo = *(uint32*)&decryptedInts[6];
auto needAck = ((seqNo & 0x01) != 0);
auto messageLength = *(uint32*)&decryptedInts[7];
auto fullDataLength = kEncryptedHeaderIntsCount * kIntSize + messageLength; // Without padding.
constexpr auto kMaxPaddingSize = 15U;
auto paddingSize = encryptedBytesCount - fullDataLength; // Can underflow.
auto badMessageLength = (/*paddingSize < 0 || */paddingSize > kMaxPaddingSize);
auto hashedDataLength = badMessageLength ? encryptedBytesCount : fullDataLength;
auto sha1ForMsgKeyCheck = hashSha1(decryptedInts, hashedDataLength);
if (memcmp(&msgKey, sha1ForMsgKeyCheck.data() + sha1ForMsgKeyCheck.size() - sizeof(msgKey), sizeof(msgKey)) != 0) {
LOG(("TCP Error: bad SHA1 hash after aesDecrypt in message."));
TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encryptedInts, encryptedBytesCount).str()));
return restartOnError();
}
if (badMessageLength || (messageLength & 0x03)) {
LOG(("TCP Error: bad msg_len received %1, data size: %2").arg(messageLength).arg(encryptedBytesCount));
TCP_LOG(("TCP Error: bad message %1").arg(Logs::mb(encryptedInts, encryptedBytesCount).str()));
return restartOnError();
}
TCP_LOG(("TCP Info: decrypted message %1,%2,%3 is %4 len").arg(msgId).arg(seqNo).arg(Logs::b(needAck)).arg(fullDataLength));
uint64 serverSession = sessionData->getSession();
if (session != serverSession) {
LOG(("MTP Error: bad server session received"));
TCP_LOG(("MTP Error: bad server session %1 instead of %2 in message received").arg(session).arg(serverSession));
_conn->received().pop_front();
lockFinished.unlock();
return restart();
return restartOnError();
}
_conn->received().pop_front();
int32 serverTime((int32)(msgId >> 32)), clientTime(unixtime());
bool isReply = ((msgId & 0x03) == 1);
if (!isReply && ((msgId & 0x03) != 3)) {
LOG(("MTP Error: bad msg_id %1 in message received").arg(msgId));
lockFinished.unlock();
return restart();
return restartOnError();
}
bool badTime = false;
@ -1430,8 +1440,9 @@ void ConnectionPrivate::handleReceived() {
if (needAck) ackRequestData.push_back(MTP_long(msgId));
auto res = HandleResult::Success; // if no need to handle, then succeed
end = data + 8 + (msgLen >> 2);
const mtpPrime *sfrom(data + 4);
auto from = decryptedInts + kEncryptedHeaderIntsCount;
auto end = from + (messageLength / kIntSize);
auto sfrom = decryptedInts + 4U; // msg_id + seq_no + length + message
MTP_LOG(_shiftedDcId, ("Recv: ") + mtpTextSerialize(sfrom, end));
bool needToHandle = false;
@ -1470,8 +1481,7 @@ void ConnectionPrivate::handleReceived() {
if (res != HandleResult::Success && res != HandleResult::Ignored) {
_needSessionReset = (res == HandleResult::ResetSession);
lockFinished.unlock();
return restart();
return restartOnError();
}
retryTimeout = 1; // reset restart() timer
@ -2891,15 +2901,16 @@ bool ConnectionPrivate::readResponseNotSecure(TResponse &response) {
onReceivedSome();
try {
if (_conn->received().isEmpty()) {
if (_conn->received().empty()) {
LOG(("AuthKey Error: trying to read response from empty received list"));
return false;
}
mtpBuffer buffer(_conn->received().front());
auto buffer = std::move(_conn->received().front());
_conn->received().pop_front();
const mtpPrime *answer(buffer.constData());
uint32 len = buffer.size();
auto answer = buffer.constData();
auto len = buffer.size();
if (len < 5) {
LOG(("AuthKey Error: bad request answer, len = %1").arg(len * sizeof(mtpPrime)));
DEBUG_LOG(("AuthKey Error: answer bytes %1").arg(Logs::mb(answer, len * sizeof(mtpPrime)).str()));

6
Telegram/SourceFiles/mtproto/connection_abstract.h
View file

@ -60,9 +60,9 @@ public:
virtual QString transport() const = 0;
typedef QList<mtpBuffer> BuffersQueue;
using BuffersQueue = std::deque<mtpBuffer>;
BuffersQueue &received() {
return receivedQueue;
return _receivedQueue;
}
// Used to emit error(...) with no real code from the server.
@ -78,7 +78,7 @@ signals:
void disconnected();
protected:
BuffersQueue receivedQueue; // list of received packets, not processed yet
BuffersQueue _receivedQueue; // list of received packets, not processed yet
bool _sentEncrypted;
// first we always send fake MTPReq_pq to see if connection works at all

4
Telegram/SourceFiles/mtproto/connection_auto.cpp
View file

@ -208,7 +208,7 @@ void AutoConnection::requestFinished(QNetworkReply *reply) {
}
} else if (!data.isEmpty()) {
if (status == UsingHttp) {
receivedQueue.push_back(data);
_receivedQueue.push_back(data);
emit receivedData();
} else if (status == WaitingBoth || status == WaitingHttp) {
try {
@ -271,7 +271,7 @@ void AutoConnection::socketPacket(const char *packet, uint32 length) {
LOG(("Strange Tcp Error; status %1").arg(status));
}
} else if (status == UsingTcp) {
receivedQueue.push_back(data);
_receivedQueue.push_back(data);
emit receivedData();
} else if (status == WaitingBoth || status == WaitingTcp || status == HttpReady) {
tcpTimeoutTimer.stop();

2
Telegram/SourceFiles/mtproto/connection_http.cpp
View file

@ -165,7 +165,7 @@ void HTTPConnection::requestFinished(QNetworkReply *reply) {
emit error(data[0]);
} else if (!data.isEmpty()) {
if (status == UsingHttp) {
receivedQueue.push_back(data);
_receivedQueue.push_back(data);
emit receivedData();
} else {
try {

2
Telegram/SourceFiles/mtproto/connection_tcp.cpp
View file

@ -351,7 +351,7 @@ void TCPConnection::socketPacket(const char *packet, uint32 length) {
if (data.size() == 1) {
emit error(data[0]);
} else if (status == UsingTcp) {
receivedQueue.push_back(data);
_receivedQueue.push_back(data);
emit receivedData();
} else if (status == WaitingTcp) {
tcpTimeoutTimer.stop();