nodejs: add crypto APIs and relocatable npm prebuilds

nodejs/crypto.cpp

@@ -0,0 +1,306 @@
+#include "crypto.h"
+
+#include <algorithm>
+#include <cmath>
+#include <variant>
+
+namespace opendht_node {
+namespace {
+
+using PublicKey = std::shared_ptr<dht::crypto::PublicKey>;
+using PrivateKey = std::shared_ptr<dht::crypto::PrivateKey>;
+using Certificate = std::shared_ptr<dht::crypto::Certificate>;
+using Identity = dht::crypto::Identity;
+using Handle = std::variant<PublicKey, PrivateKey, Certificate, Identity>;
+
+constexpr napi_type_tag cryptoTag {0x37cdf3e4648e4cb5ULL, 0x964fb031062c245aULL};
+
+Handle&
+handle(Napi::Value value)
+{
+    bool matches = false;
+    if (!value.IsExternal() || napi_check_object_type_tag(value.Env(), value, &cryptoTag, &matches) != napi_ok
+        || !matches)
+        throw Napi::TypeError::New(value.Env(), "Invalid OpenDHT crypto handle");
+    return *value.As<Napi::External<Handle>>().Data();
+}
+
+template<typename Type>
+Type
+read(Napi::Value value)
+{
+    if (auto result = std::get_if<Type>(&handle(value)))
+        return *result;
+    throw Napi::TypeError::New(value.Env(), "Wrong OpenDHT crypto handle type");
+}
+
+Napi::Value
+wrap(Napi::Env env, Handle value)
+{
+    auto owner = std::make_unique<Handle>(std::move(value));
+    auto result = Napi::External<Handle>::New(env, owner.get(), [](Napi::Env, Handle* data) { delete data; });
+    owner.release();
+    if (napi_type_tag_object(env, result, &cryptoTag) != napi_ok)
+        throw Napi::Error::New(env, "Could not tag OpenDHT crypto handle");
+    return result;
+}
+
+dht::Blob
+bytes(Napi::Value value)
+{
+    if (!value.IsTypedArray() || value.As<Napi::TypedArray>().TypedArrayType() != napi_uint8_array)
+        throw Napi::TypeError::New(value.Env(), "Expected a Uint8Array");
+    auto array = value.As<Napi::Uint8Array>();
+    if (array.ElementLength() > 16 * 1024 * 1024)
+        throw Napi::RangeError::New(value.Env(), "Crypto input exceeds 16 MiB");
+    dht::Blob result(array.ElementLength());
+    if (!result.empty())
+        std::copy_n(array.Data(), result.size(), result.data());
+    return result;
+}
+
+std::string
+string(Napi::Value value)
+{
+    if (!value.IsString())
+        throw Napi::TypeError::New(value.Env(), "Expected a string");
+    auto result = value.As<Napi::String>().Utf8Value();
+    if (result.find('\0') != std::string::npos)
+        throw Napi::TypeError::New(value.Env(), "Crypto strings must not contain NUL bytes");
+    return result;
+}
+
+Napi::Buffer<uint8_t>
+buffer(Napi::Env env, const dht::Blob& value)
+{
+    return Napi::Buffer<uint8_t>::Copy(env, value.data(), value.size());
+}
+
+PublicKey
+publicKey(const Handle& value)
+{
+    if (auto key = std::get_if<PublicKey>(&value))
+        return *key;
+    if (auto key = std::get_if<PrivateKey>(&value))
+        return (*key)->getSharedPublicKey();
+    if (auto certificate = std::get_if<Certificate>(&value))
+        return (*certificate)->getSharedPublicKey();
+    return std::get<Identity>(value).second->getSharedPublicKey();
+}
+
+class GenerateWorker : public Napi::AsyncWorker
+{
+public:
+    GenerateWorker(Napi::Env env, bool identity, std::string name, bool rsa, unsigned bits)
+        : Napi::AsyncWorker(env, "OpenDHT crypto generation")
+        , deferred_(Napi::Promise::Deferred::New(env))
+        , identity_(identity)
+        , name_(std::move(name))
+        , rsa_(rsa)
+        , bits_(bits)
+    {}
+
+    Napi::Promise promise() const { return deferred_.Promise(); }
+
+    void Execute() override
+    {
+        try {
+            if (identity_)
+                result_ = rsa_ ? dht::crypto::generateIdentity(name_, {}, bits_)
+                               : dht::crypto::generateEcIdentity(name_);
+            else
+                result_ = std::make_shared<dht::crypto::PrivateKey>(rsa_ ? dht::crypto::PrivateKey::generate(bits_)
+                                                                         : dht::crypto::PrivateKey::generateEC());
+        } catch (const std::exception& error) {
+            SetError(error.what());
+        }
+    }
+
+    void OnOK() override { deferred_.Resolve(wrap(Env(), std::move(result_))); }
+    void OnError(const Napi::Error& error) override { deferred_.Reject(error.Value()); }
+
+private:
+    Napi::Promise::Deferred deferred_;
+    bool identity_;
+    std::string name_;
+    bool rsa_;
+    unsigned bits_;
+    Handle result_;
+};
+
+Napi::Value
+generate(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        const auto kind = string(info[0]);
+        const auto name = string(info[1]);
+        const auto algorithm = string(info[2]);
+        if (algorithm != "rsa" && algorithm != "ec")
+            throw Napi::TypeError::New(info.Env(), "algorithm must be rsa or ec");
+        if (!info[3].IsNumber())
+            throw Napi::TypeError::New(info.Env(), "bits must be a number");
+        const auto bits = info[3].As<Napi::Number>().DoubleValue();
+        if (!std::isfinite(bits) || std::floor(bits) != bits || bits < 2048 || bits > 8192)
+            throw Napi::RangeError::New(info.Env(), "RSA bits must be an integer between 2048 and 8192");
+        if (kind != "private" && kind != "identity")
+            throw Napi::TypeError::New(info.Env(), "Invalid crypto generation type");
+        auto worker = std::make_unique<GenerateWorker>(info.Env(), kind == "identity", name, algorithm == "rsa", bits);
+        auto promise = worker->promise();
+        worker->Queue();
+        worker.release();
+        return promise;
+    });
+}
+
+Napi::Value
+import(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        const auto kind = string(info[0]);
+        auto data = bytes(info[1]);
+        if (data.empty())
+            throw Napi::TypeError::New(info.Env(), "Crypto imports must not be empty");
+        if (kind == "private")
+            return wrap(info.Env(), std::make_shared<dht::crypto::PrivateKey>(data, string(info[2])));
+        if (kind == "public")
+            return wrap(info.Env(), std::make_shared<dht::crypto::PublicKey>(data));
+        if (kind == "certificate")
+            return wrap(info.Env(), std::make_shared<dht::crypto::Certificate>(data));
+        throw Napi::TypeError::New(info.Env(), "Invalid crypto import type");
+    });
+}
+
+Napi::Value
+serialize(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        auto& value = handle(info[0]);
+        if (auto key = std::get_if<PrivateKey>(&value))
+            return buffer(info.Env(), (*key)->serialize(string(info[1])));
+        if (auto certificate = std::get_if<Certificate>(&value))
+            return buffer(info.Env(), (*certificate)->getPacked());
+        dht::Blob result;
+        readPublicKey(info[0])->pack(result);
+        return buffer(info.Env(), result);
+    });
+}
+
+Napi::Value
+getPublicKey(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&] { return wrap(info.Env(), publicKey(handle(info[0]))); });
+}
+
+Napi::Value
+getId(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        const auto key = publicKey(handle(info[0]));
+        if (!info[1].IsBoolean())
+            throw Napi::TypeError::New(info.Env(), "Expected a boolean");
+        return Napi::String::New(info.Env(),
+                                 info[1].As<Napi::Boolean>().Value() ? key->getLongId().toString()
+                                                                     : key->getId().toString());
+    });
+}
+
+Napi::Value
+sign(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        return buffer(info.Env(), read<PrivateKey>(info[0])->sign(bytes(info[1])));
+    });
+}
+
+Napi::Value
+verify(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        return Napi::Boolean::New(info.Env(), readPublicKey(info[0])->checkSignature(bytes(info[1]), bytes(info[2])));
+    });
+}
+
+Napi::Value
+encrypt(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        const auto key = readEncryptionKey(info[0]);
+        return buffer(info.Env(), key->encrypt(bytes(info[1])));
+    });
+}
+
+Napi::Value
+decrypt(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        return buffer(info.Env(), read<PrivateKey>(info[0])->decrypt(bytes(info[1])));
+    });
+}
+
+Napi::Value
+identity(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        auto key = read<PrivateKey>(info[0]);
+        auto certificate = read<Certificate>(info[1]);
+        if (key->getPublicKey().getLongId() != certificate->getLongId())
+            throw Napi::TypeError::New(info.Env(), "Identity key and certificate do not match");
+        return wrap(info.Env(), Identity {std::move(key), std::move(certificate)});
+    });
+}
+
+Napi::Value
+identityPart(const Napi::CallbackInfo& info)
+{
+    return guarded(info, [&]() -> Napi::Value {
+        const auto value = readIdentity(info[0]);
+        if (!info[1].IsBoolean())
+            throw Napi::TypeError::New(info.Env(), "Expected a boolean");
+        return info[1].As<Napi::Boolean>().Value() ? wrap(info.Env(), value.first) : wrap(info.Env(), value.second);
+    });
+}
+
+} // namespace
+
+dht::crypto::Identity
+readIdentity(Napi::Value value)
+{
+    return read<Identity>(value);
+}
+std::shared_ptr<dht::crypto::PublicKey>
+readPublicKey(Napi::Value value)
+{
+    return read<PublicKey>(value);
+}
+
+std::shared_ptr<dht::crypto::PublicKey>
+readEncryptionKey(Napi::Value value)
+{
+    const auto key = readPublicKey(value);
+    const auto algorithm = gnutls_pubkey_get_pk_algorithm(key->pk, nullptr);
+    if (algorithm != GNUTLS_PK_RSA
+#if GNUTLS_VERSION_NUMBER >= 0x030804
+        && algorithm != GNUTLS_PK_RSA_OAEP
+#endif
+    )
+        throw Napi::TypeError::New(value.Env(), "Encryption requires an RSA public key");
+    return key;
+}
+
+void
+initializeCrypto(Napi::Env env, Napi::Object exports)
+{
+    exports.Set("cryptoGenerate", Napi::Function::New(env, generate));
+    exports.Set("cryptoImport", Napi::Function::New(env, import));
+    exports.Set("cryptoSerialize", Napi::Function::New(env, serialize));
+    exports.Set("cryptoPublicKey", Napi::Function::New(env, getPublicKey));
+    exports.Set("cryptoId", Napi::Function::New(env, getId));
+    exports.Set("cryptoSign", Napi::Function::New(env, sign));
+    exports.Set("cryptoVerify", Napi::Function::New(env, verify));
+    exports.Set("cryptoEncrypt", Napi::Function::New(env, encrypt));
+    exports.Set("cryptoDecrypt", Napi::Function::New(env, decrypt));
+    exports.Set("cryptoIdentity", Napi::Function::New(env, identity));
+    exports.Set("cryptoIdentityPart", Napi::Function::New(env, identityPart));
+}
+
+} // namespace opendht_node