1 files changed, 204 insertions, 0 deletions
diff --git a/src/qt/paymentrequestplus.cpp b/src/qt/paymentrequestplus.cpp
new file mode 100644
index 0000000000..289ddabb92
--- /dev/null
+++ b/src/qt/paymentrequestplus.cpp
@@ -0,0 +1,204 @@
+//
+// Wraps dumb protocol buffer paymentRequest
+// with some extra methods
+//
+
+#include <QDateTime>
+#include <QDebug>
+#include <QSslCertificate>
+
+#include <openssl/x509.h>
+#include <openssl/x509_vfy.h>
+
+#include <stdexcept>
+
+#include "paymentrequestplus.h"
+
+class SSLVerifyError : public std::runtime_error
+{
+public:
+    SSLVerifyError(std::string err) : std::runtime_error(err) { }
+};
+
+bool PaymentRequestPlus::parse(const QByteArray& data)
+{
+    bool parseOK = paymentRequest.ParseFromArray(data.data(), data.size());
+    if (!parseOK) {
+        qDebug() << "Error parsing payment request";
+        return false;
+    }
+    if (paymentRequest.payment_details_version() > 1) {
+        qDebug() << "Received up-version payment details, version=" << paymentRequest.payment_details_version();
+        return false;
+    }
+
+    parseOK = details.ParseFromString(paymentRequest.serialized_payment_details());
+    if (!parseOK)
+    {
+        qDebug() << "Error parsing payment details";
+        paymentRequest.Clear();
+        return false;
+    }
+    return true;
+}
+
+bool PaymentRequestPlus::SerializeToString(string* output) const
+{
+    return paymentRequest.SerializeToString(output);
+}
+
+bool PaymentRequestPlus::IsInitialized() const
+{
+    return paymentRequest.IsInitialized();
+}
+
+QString PaymentRequestPlus::getPKIType() const
+{
+    if (!IsInitialized()) return QString("none");
+    return QString::fromStdString(paymentRequest.pki_type());
+}
+
+bool PaymentRequestPlus::getMerchant(X509_STORE* certStore, QString& merchant) const
+{
+    merchant.clear();
+
+    if (!IsInitialized())
+        return false;
+
+    // One day we'll support more PKI types, but just
+    // x509 for now:
+    const EVP_MD* digestAlgorithm = NULL;
+    if (paymentRequest.pki_type() == "x509+sha256") {
+        digestAlgorithm = EVP_sha256();
+    }
+    else if (paymentRequest.pki_type() == "x509+sha1") {
+        digestAlgorithm = EVP_sha1();
+    }
+    else if (paymentRequest.pki_type() == "none") {
+        if (fDebug) qDebug() << "PaymentRequest: pki_type == none";
+        return false;
+    }
+    else {
+        qDebug() << "PaymentRequest: unknown pki_type " << paymentRequest.pki_type().c_str();
+        return false;
+    }
+
+    payments::X509Certificates certChain;
+    if (!certChain.ParseFromString(paymentRequest.pki_data())) {
+        qDebug() << "PaymentRequest: error parsing pki_data";
+        return false;
+    }
+
+    std::vector<X509*> certs;
+    const QDateTime currentTime = QDateTime::currentDateTime();
+    for (int i = 0; i < certChain.certificate_size(); i++) {
+        QByteArray certData(certChain.certificate(i).data(), certChain.certificate(i).size());
+        QSslCertificate qCert(certData, QSsl::Der);
+        if (currentTime < qCert.effectiveDate() || currentTime > qCert.expiryDate()) {
+            qDebug() << "PaymentRequest: certificate expired or not yet active: " << qCert;
+            return false;
+        }
+#if QT_VERSION >= 0x050000
+        if (qCert.isBlacklisted()) {
+            qDebug() << "PaymentRequest: certificate blacklisted: " << qCert;
+            return false;
+        }
+#endif
+        const unsigned char *data = (const unsigned char *)certChain.certificate(i).data();
+        X509 *cert = d2i_X509(NULL, &data, certChain.certificate(i).size());
+        if (cert)
+            certs.push_back(cert);
+    }
+    if (certs.empty()) {
+        qDebug() << "PaymentRequest: empty certificate chain";
+        return false;
+    }
+
+    // The first cert is the signing cert, the rest are untrusted certs that chain
+    // to a valid root authority. OpenSSL needs them separately.
+    STACK_OF(X509) *chain = sk_X509_new_null();
+    for (int i = certs.size()-1; i > 0; i--) {
+        sk_X509_push(chain, certs[i]);
+    }
+    X509 *signing_cert = certs[0];
+
+    // Now create a "store context", which is a single use object for checking,
+    // load the signing cert into it and verify.
+    X509_STORE_CTX *store_ctx = X509_STORE_CTX_new();
+    if (!store_ctx) {
+        qDebug() << "PaymentRequest: error creating X509_STORE_CTX";
+        return false;
+    }
+
+    char *website = NULL;
+    bool fResult = true;
+    try
+    {
+        if (!X509_STORE_CTX_init(store_ctx, certStore, signing_cert, chain))
+        {
+            int error = X509_STORE_CTX_get_error(store_ctx);
+            throw SSLVerifyError(X509_verify_cert_error_string(error));
+        }
+
+        // Now do the verification!
+        int result = X509_verify_cert(store_ctx);
+        if (result != 1) {
+            int error = X509_STORE_CTX_get_error(store_ctx);
+            throw SSLVerifyError(X509_verify_cert_error_string(error));
+        }
+        X509_NAME *certname = X509_get_subject_name(signing_cert);
+
+        // Valid cert; check signature:
+        payments::PaymentRequest rcopy(paymentRequest); // Copy
+        rcopy.set_signature(std::string(""));
+        std::string data_to_verify;                 // Everything but the signature
+        rcopy.SerializeToString(&data_to_verify);
+
+        EVP_MD_CTX ctx;
+        EVP_PKEY *pubkey = X509_get_pubkey(signing_cert);
+        EVP_MD_CTX_init(&ctx);
+        if (!EVP_VerifyInit_ex(&ctx, digestAlgorithm, NULL) ||
+            !EVP_VerifyUpdate(&ctx, data_to_verify.data(), data_to_verify.size()) ||
+            !EVP_VerifyFinal(&ctx, (const unsigned char*)paymentRequest.signature().data(), paymentRequest.signature().size(), pubkey)) {
+
+            throw SSLVerifyError("Bad signature, invalid PaymentRequest.");
+        }
+
+        // OpenSSL API for getting human printable strings from certs is baroque.
+        int textlen = X509_NAME_get_text_by_NID(certname, NID_commonName, NULL, 0);
+        website = new char[textlen + 1];
+        if (X509_NAME_get_text_by_NID(certname, NID_commonName, website, textlen + 1) == textlen && textlen > 0) {
+            merchant = website;
+        }
+        else {
+            throw SSLVerifyError("Bad certificate, missing common name");
+        }
+        // TODO: detect EV certificates and set merchant = business name instead of unfriendly NID_commonName ?
+    }
+    catch (SSLVerifyError& err)
+    {
+        fResult = false;
+        qDebug() << "PaymentRequestPlus::getMerchant SSL err: " << err.what();
+    }
+
+    if (website)
+        delete[] website;
+    X509_STORE_CTX_free(store_ctx);
+    for (unsigned int i = 0; i < certs.size(); i++)
+        X509_free(certs[i]);
+
+    return fResult;
+}
+
+QList<std::pair<CScript,qint64> > PaymentRequestPlus::getPayTo() const
+{
+    QList<std::pair<CScript,qint64> > result;
+    for (int i = 0; i < details.outputs_size(); i++)
+    {
+        const unsigned char* scriptStr = (const unsigned char*)details.outputs(i).script().data();
+        CScript s(scriptStr, scriptStr+details.outputs(i).script().size());
+
+        result.append(make_pair(s, details.outputs(i).amount()));
+    }
+    return result;
+}