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Offload DH key exchange crypto to background thread #30595

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185 changes: 99 additions & 86 deletions Telegram/SourceFiles/calls/calls_call.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -288,25 +288,6 @@ Call::Call(
setupOutgoingVideo();
}

void Call::generateModExpFirst(bytes::const_span randomSeed) {
Expects(!conferenceInvite());

auto first = MTP::CreateModExp(_dhConfig.g, _dhConfig.p, randomSeed);
if (first.modexp.empty()) {
LOG(("Call Error: Could not compute mod-exp first."));
finish(FinishType::Failed);
return;
}

_randomPower = std::move(first.randomPower);
if (_type == Type::Incoming) {
_gb = std::move(first.modexp);
} else {
_ga = std::move(first.modexp);
_gaHash = openssl::Sha256(_ga);
}
}

bool Call::isIncomingWaiting() const {
if (type() != Call::Type::Incoming) {
return false;
Expand All @@ -324,18 +305,38 @@ void Call::start(bytes::const_span random) {
Assert(_dhConfig.g != 0);
Assert(!_dhConfig.p.empty());

generateModExpFirst(random);
const auto state = _state.current();
if (state == State::Starting || state == State::Requesting) {
if (_type == Type::Outgoing) {
startOutgoing();
} else {
startIncoming();
}
} else if (state == State::ExchangingKeys
&& _answerAfterDhConfigReceived) {
answer();
}
const auto g = _dhConfig.g;
const auto p = _dhConfig.p;
auto randomCopy = bytes::vector(random.begin(), random.end());
const auto weak = base::make_weak(this);
crl::async([=, randomCopy = std::move(randomCopy)]() mutable {
auto first = MTP::CreateModExp(g, p, randomCopy);
crl::on_main(weak, [=, first = std::move(first)]() mutable {
if (first.modexp.empty()) {
LOG(("Call Error: Could not compute mod-exp first."));
finish(FinishType::Failed);
return;
}
_randomPower = std::move(first.randomPower);
if (_type == Type::Incoming) {
_gb = std::move(first.modexp);
} else {
_ga = std::move(first.modexp);
_gaHash = openssl::Sha256(_ga);
}
const auto state = _state.current();
if (state == State::Starting || state == State::Requesting) {
if (_type == Type::Outgoing) {
startOutgoing();
} else {
startIncoming();
}
} else if (state == State::ExchangingKeys
&& _answerAfterDhConfigReceived) {
answer();
}
});
});
}

void Call::startOutgoing() {
Expand Down Expand Up @@ -784,7 +785,7 @@ bool Call::handleUpdate(const MTPPhoneCall &call) {
if (_type == Type::Incoming
&& _state.current() == State::ExchangingKeys
&& !_instance) {
startConfirmedCall(data);
startConfirmedCall(call);
}
} return true;

Expand Down Expand Up @@ -951,53 +952,58 @@ void Call::confirmAcceptedCall(const MTPDphoneCallAccepted &call) {
return;
}

const auto firstBytes = bytes::make_span(call.vg_b().v);
const auto computedAuthKey = MTP::CreateAuthKey(
firstBytes,
_randomPower,
_dhConfig.p);
if (computedAuthKey.empty()) {
LOG(("Call Error: Could not compute mod-exp final."));
finish(FinishType::Failed);
return;
}

MTP::AuthKey::FillData(_authKey, computedAuthKey);
_keyFingerprint = ComputeFingerprint(_authKey);

setState(State::ExchangingKeys);
_api.request(MTPphone_ConfirmCall(
MTP_inputPhoneCall(MTP_long(_id), MTP_long(_accessHash)),
MTP_bytes(_ga),
MTP_long(_keyFingerprint),
MTP_phoneCallProtocol(
MTP_flags(MTPDphoneCallProtocol::Flag::f_udp_p2p
| MTPDphoneCallProtocol::Flag::f_udp_reflector),
MTP_int(kMinLayer),
MTP_int(tgcalls::Meta::MaxLayer()),
MTP_vector(CollectVersionsForApi()))
)).done([=](const MTPphone_PhoneCall &result) {
Expects(result.type() == mtpc_phone_phoneCall);

const auto &call = result.c_phone_phoneCall();
_user->session().data().processUsers(call.vusers());
if (call.vphone_call().type() != mtpc_phoneCall) {
LOG(("Call Error: Expected phoneCall in response to "
"phone.confirmCall()"));
finish(FinishType::Failed);
return;
}
auto firstBytesData = bytes::vector(
call.vg_b().v.begin(),
call.vg_b().v.end());
const auto randomPower = _randomPower;
const auto prime = _dhConfig.p;
const auto weak = base::make_weak(this);
crl::async([=, firstBytesData = std::move(firstBytesData)]() mutable {
auto key = MTP::CreateAuthKey(firstBytesData, randomPower, prime);
crl::on_main(weak, [=, key = std::move(key)]() mutable {
if (key.empty()) {
LOG(("Call Error: Could not compute mod-exp final."));
finish(FinishType::Failed);
return;
}
MTP::AuthKey::FillData(_authKey, key);
_keyFingerprint = ComputeFingerprint(_authKey);
_api.request(MTPphone_ConfirmCall(
MTP_inputPhoneCall(MTP_long(_id), MTP_long(_accessHash)),
MTP_bytes(_ga),
MTP_long(_keyFingerprint),
MTP_phoneCallProtocol(
MTP_flags(MTPDphoneCallProtocol::Flag::f_udp_p2p
| MTPDphoneCallProtocol::Flag::f_udp_reflector),
MTP_int(kMinLayer),
MTP_int(tgcalls::Meta::MaxLayer()),
MTP_vector(CollectVersionsForApi()))
)).done([=](const MTPphone_PhoneCall &result) {
Expects(result.type() == mtpc_phone_phoneCall);

const auto &call = result.c_phone_phoneCall();
_user->session().data().processUsers(call.vusers());
if (call.vphone_call().type() != mtpc_phoneCall) {
LOG(("Call Error: Expected phoneCall in response to "
"phone.confirmCall()"));
finish(FinishType::Failed);
return;
}

createAndStartController(call.vphone_call().c_phoneCall());
}).fail([=](const MTP::Error &error) {
handleRequestError(error.type());
}).send();
createAndStartController(call.vphone_call().c_phoneCall());
}).fail([=](const MTP::Error &error) {
handleRequestError(error.type());
}).send();
});
});
}

void Call::startConfirmedCall(const MTPDphoneCall &call) {
void Call::startConfirmedCall(MTPPhoneCall phoneCall) {
Expects(_type == Type::Incoming);
Expects(!conferenceInvite());

const auto &call = phoneCall.c_phoneCall();
const auto firstBytes = bytes::make_span(call.vg_a_or_b().v);
if (_gaHash != openssl::Sha256(firstBytes)) {
LOG(("Call Error: Wrong g_a hash received."));
Expand All @@ -1006,20 +1012,27 @@ void Call::startConfirmedCall(const MTPDphoneCall &call) {
}
_ga = bytes::vector(firstBytes.begin(), firstBytes.end());

const auto computedAuthKey = MTP::CreateAuthKey(
firstBytes,
_randomPower,
_dhConfig.p);
if (computedAuthKey.empty()) {
LOG(("Call Error: Could not compute mod-exp final."));
finish(FinishType::Failed);
return;
}

MTP::AuthKey::FillData(_authKey, computedAuthKey);
_keyFingerprint = ComputeFingerprint(_authKey);

createAndStartController(call);
auto firstBytesData = bytes::vector(firstBytes.begin(), firstBytes.end());
const auto randomPower = _randomPower;
const auto prime = _dhConfig.p;
const auto weak = base::make_weak(this);
crl::async([=,
firstBytesData = std::move(firstBytesData),
phoneCall = std::move(phoneCall)]() mutable {
auto key = MTP::CreateAuthKey(firstBytesData, randomPower, prime);
crl::on_main(weak, [=,
key = std::move(key),
phoneCall = std::move(phoneCall)]() mutable {
if (key.empty()) {
LOG(("Call Error: Could not compute mod-exp final."));
finish(FinishType::Failed);
return;
}
MTP::AuthKey::FillData(_authKey, key);
_keyFingerprint = ComputeFingerprint(_authKey);
createAndStartController(phoneCall.c_phoneCall());
});
});
}

void Call::createAndStartController(const MTPDphoneCall &call) {
Expand Down
3 changes: 1 addition & 2 deletions Telegram/SourceFiles/calls/calls_call.h
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Original file line number Diff line number Diff line change
Expand Up @@ -295,7 +295,6 @@ class Call final
void startWaitingTrack();
void sendSignalingData(const QByteArray &data);

void generateModExpFirst(bytes::const_span randomSeed);
void handleControllerStateChange(tgcalls::State state);
void handleControllerBarCountChange(int count);
void createAndStartController(const MTPDphoneCall &call);
Expand All @@ -308,7 +307,7 @@ class Call final
void actuallyAnswer();
void acceptConferenceInvite();
void confirmAcceptedCall(const MTPDphoneCallAccepted &call);
void startConfirmedCall(const MTPDphoneCall &call);
void startConfirmedCall(MTPPhoneCall call);
void setState(State state);
void setStateQueued(State state);
void setFailedQueued(const QString &error);
Expand Down