tdesktop/Telegram/SourceFiles/mtproto/special_config_request.cpp

229 lines
8.3 KiB
C++

/*
This file is part of Telegram Desktop,
the official desktop application for the Telegram messaging service.
For license and copyright information please follow this link:
https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
*/
#include "mtproto/special_config_request.h"
#include "mtproto/rsa_public_key.h"
#include "mtproto/dc_options.h"
#include "mtproto/auth_key.h"
#include "base/openssl_help.h"
#include <openssl/aes.h>
namespace MTP {
namespace {
constexpr auto kPublicKey = str_const("\
-----BEGIN RSA PUBLIC KEY-----\n\
MIIBCgKCAQEAyr+18Rex2ohtVy8sroGPBwXD3DOoKCSpjDqYoXgCqB7ioln4eDCF\n\
fOBUlfXUEvM/fnKCpF46VkAftlb4VuPDeQSS/ZxZYEGqHaywlroVnXHIjgqoxiAd\n\
192xRGreuXIaUKmkwlM9JID9WS2jUsTpzQ91L8MEPLJ/4zrBwZua8W5fECwCCh2c\n\
9G5IzzBm+otMS/YKwmR1olzRCyEkyAEjXWqBI9Ftv5eG8m0VkBzOG655WIYdyV0H\n\
fDK/NWcvGqa0w/nriMD6mDjKOryamw0OP9QuYgMN0C9xMW9y8SmP4h92OAWodTYg\n\
Y1hZCxdv6cs5UnW9+PWvS+WIbkh+GaWYxwIDAQAB\n\
-----END RSA PUBLIC KEY-----\
");
} // namespace
SpecialConfigRequest::SpecialConfigRequest(base::lambda<void(DcId dcId, const std::string &ip, int port)> callback) : _callback(std::move(callback)) {
App::setProxySettings(_manager);
performAppRequest();
performDnsRequest();
}
void SpecialConfigRequest::performAppRequest() {
auto appUrl = QUrl();
appUrl.setScheme(qsl("https"));
appUrl.setHost(qsl("google.com"));
if (cTestMode()) {
appUrl.setPath(qsl("/test/"));
}
auto appRequest = QNetworkRequest(appUrl);
appRequest.setRawHeader("Host", "dns-telegram.appspot.com");
_appReply.reset(_manager.get(appRequest));
connect(_appReply.get(), &QNetworkReply::finished, this, [this] { appFinished(); });
}
void SpecialConfigRequest::performDnsRequest() {
auto dnsUrl = QUrl();
dnsUrl.setScheme(qsl("https"));
dnsUrl.setHost(qsl("google.com"));
dnsUrl.setPath(qsl("/resolve"));
dnsUrl.setQuery(qsl("name=%1.stel.com&type=16").arg(cTestMode() ? qsl("tap") : qsl("ap")));
auto dnsRequest = QNetworkRequest(QUrl(dnsUrl));
dnsRequest.setRawHeader("Host", "dns.google.com");
_dnsReply.reset(_manager.get(dnsRequest));
connect(_dnsReply.get(), &QNetworkReply::finished, this, [this] { dnsFinished(); });
}
void SpecialConfigRequest::appFinished() {
if (!_appReply) {
return;
}
auto result = _appReply->readAll();
_appReply.release()->deleteLater();
handleResponse(result);
}
void SpecialConfigRequest::dnsFinished() {
if (!_dnsReply) {
return;
}
if (_dnsReply->error() != QNetworkReply::NoError) {
LOG(("Config Error: Failed to get dns response JSON, error: %1 (%2)").arg(_dnsReply->errorString()).arg(_dnsReply->error()));
}
auto result = _dnsReply->readAll();
_dnsReply.release()->deleteLater();
// Read and store to "entries" map all the data bytes from this response:
// { .., "Answer": [ { .., "data": "bytes1", .. }, { .., "data": "bytes2", .. } ], .. }
auto entries = QMap<int, QString>();
auto error = QJsonParseError { 0, QJsonParseError::NoError };
auto document = QJsonDocument::fromJson(result, &error);
if (error.error != QJsonParseError::NoError) {
LOG(("Config Error: Failed to parse dns response JSON, error: %1").arg(error.errorString()));
} else if (!document.isObject()) {
LOG(("Config Error: Not an object received in dns response JSON."));
} else {
auto response = document.object();
auto answerIt = response.find(qsl("Answer"));
if (answerIt == response.constEnd()) {
LOG(("Config Error: Could not find Answer in dns response JSON."));
} else if (!(*answerIt).isArray()) {
LOG(("Config Error: Not an array received in Answer in dns response JSON."));
} else {
for (auto elem : (*answerIt).toArray()) {
if (!elem.isObject()) {
LOG(("Config Error: Not an object found in Answer array in dns response JSON."));
} else {
auto object = elem.toObject();
auto dataIt = object.find(qsl("data"));
if (dataIt == object.constEnd()) {
LOG(("Config Error: Could not find data in Answer array entry in dns response JSON."));
} else if (!(*dataIt).isString()) {
LOG(("Config Error: Not a string data found in Answer array entry in dns response JSON."));
} else {
auto data = (*dataIt).toString();
entries.insertMulti(INT_MAX - data.size(), data);
}
}
}
}
}
auto text = QStringList(entries.values()).join(QString());
handleResponse(text.toLatin1());
}
bool SpecialConfigRequest::decryptSimpleConfig(const QByteArray &bytes) {
auto cleanBytes = bytes;
auto removeFrom = std::remove_if(cleanBytes.begin(), cleanBytes.end(), [](char ch) {
auto isGoodBase64 = (ch == '+') || (ch == '=') || (ch == '/')
|| (ch >= 'a' && ch <= 'z')
|| (ch >= 'A' && ch <= 'Z')
|| (ch >= '0' && ch <= '9');
return !isGoodBase64;
});
if (removeFrom != cleanBytes.end()) {
cleanBytes.remove(removeFrom - cleanBytes.begin(), cleanBytes.end() - removeFrom);
}
constexpr auto kGoodSizeBase64 = 344;
if (cleanBytes.size() != kGoodSizeBase64) {
LOG(("Config Error: Bad data size %1 required %2").arg(cleanBytes.size()).arg(kGoodSizeBase64));
return false;
}
constexpr auto kGoodSizeData = 256;
auto decodedBytes = QByteArray::fromBase64(cleanBytes, QByteArray::Base64Encoding);
if (decodedBytes.size() != kGoodSizeData) {
LOG(("Config Error: Bad data size %1 required %2").arg(decodedBytes.size()).arg(kGoodSizeData));
return false;
}
auto publicKey = internal::RSAPublicKey(gsl::as_bytes(gsl::make_span(
kPublicKey.c_str(),
kPublicKey.size())));
auto decrypted = publicKey.decrypt(gsl::as_bytes(gsl::make_span(decodedBytes)));
auto decryptedBytes = gsl::make_span(decrypted);
constexpr auto kAesKeySize = CTRState::KeySize;
constexpr auto kAesIvecSize = CTRState::IvecSize;
auto aesEncryptedBytes = decryptedBytes.subspan(kAesKeySize);
base::byte_array<kAesIvecSize> aesivec;
base::copy_bytes(aesivec, decryptedBytes.subspan(CTRState::KeySize - CTRState::IvecSize, CTRState::IvecSize));
AES_KEY aeskey;
AES_set_decrypt_key(reinterpret_cast<const unsigned char*>(decryptedBytes.data()), kAesKeySize * CHAR_BIT, &aeskey);
AES_cbc_encrypt(reinterpret_cast<const unsigned char*>(aesEncryptedBytes.data()), reinterpret_cast<unsigned char*>(aesEncryptedBytes.data()), aesEncryptedBytes.size(), &aeskey, reinterpret_cast<unsigned char*>(aesivec.data()), AES_DECRYPT);
constexpr auto kDigestSize = 16;
auto dataSize = aesEncryptedBytes.size() - kDigestSize;
auto data = aesEncryptedBytes.subspan(0, dataSize);
auto hash = openssl::Sha256(data);
if (base::compare_bytes(gsl::make_span(hash).subspan(0, kDigestSize), aesEncryptedBytes.subspan(dataSize)) != 0) {
LOG(("Config Error: Bad digest."));
return false;
}
mtpBuffer buffer;
buffer.resize(data.size() / sizeof(mtpPrime));
base::copy_bytes(gsl::as_writeable_bytes(gsl::make_span(buffer)), data);
auto from = &*buffer.cbegin();
auto end = from + buffer.size();
auto realLength = *from++;
if (realLength <= 0 || realLength > dataSize || (realLength & 0x03)) {
LOG(("Config Error: Bad length %1.").arg(realLength));
return false;
}
try {
_simpleConfig.read(from, end);
} catch (...) {
LOG(("Config Error: Could not read configSimple."));
return false;
}
if ((end - from) * sizeof(mtpPrime) != (dataSize - realLength)) {
LOG(("Config Error: Bad read length %1, should be %2.").arg((end - from) * sizeof(mtpPrime)).arg(dataSize - realLength));
return false;
}
return true;
}
void SpecialConfigRequest::handleResponse(const QByteArray &bytes) {
if (!decryptSimpleConfig(bytes)) {
return;
}
Assert(_simpleConfig.type() == mtpc_help_configSimple);
auto &config = _simpleConfig.c_help_configSimple();
auto now = unixtime();
if (now < config.vdate.v || now > config.vexpires.v) {
LOG(("Config Error: Bad date frame for simple config: %1-%2, our time is %3.").arg(config.vdate.v).arg(config.vexpires.v).arg(now));
return;
}
if (config.vip_port_list.v.empty()) {
LOG(("Config Error: Empty simple config received."));
return;
}
for (auto &entry : config.vip_port_list.v) {
Assert(entry.type() == mtpc_ipPort);
auto &ipPort = entry.c_ipPort();
auto ip = *reinterpret_cast<const uint32*>(&ipPort.vipv4.v);
auto ipString = qsl("%1.%2.%3.%4").arg((ip >> 24) & 0xFF).arg((ip >> 16) & 0xFF).arg((ip >> 8) & 0xFF).arg(ip & 0xFF);
_callback(config.vdc_id.v, ipString.toStdString(), ipPort.vport.v);
}
}
SpecialConfigRequest::~SpecialConfigRequest() {
if (_appReply) {
_appReply->abort();
}
if (_dnsReply) {
_dnsReply->abort();
}
}
} // namespace MTP