[Qt] add option to allow self signed root certs (for testing)

- it is helpful to be able to test and verify payment request processing
  by allowing self signed root certificates (e.g. generated by Gavins
  "certificate authority in a box")
- This option is just shown in the UI options, if -help-debug is enabled.

src/qt/paymentrequestplus.cpp

@@ -9,6 +9,8 @@
 
 #include "paymentrequestplus.h"
 
+#include "util.h"
+
 #include <stdexcept>
 
 #include <openssl/x509.h>
@@ -150,7 +152,13 @@ bool PaymentRequestPlus::getMerchant(X509_STORE* certStore, QString& merchant) c
         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));
+            // For testing payment requests, we allow self signed root certs!
+            // This option is just shown in the UI options, if -help-debug is enabled.
+            if (!(error == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT && GetBoolArg("-allowselfsignedrootcertificates", false))) {
+                throw SSLVerifyError(X509_verify_cert_error_string(error));
+            } else {
+               qDebug() << "PaymentRequestPlus::getMerchant: Allowing self signed root certificate, because -allowselfsignedrootcertificates is true.";
+            }
         }
         X509_NAME *certname = X509_get_subject_name(signing_cert);
 

src/qt/utilitydialog.cpp

@@ -12,6 +12,7 @@
 
 #include "clientversion.h"
 #include "init.h"
+#include "util.h"
 
 #include <stdio.h>
 
@@ -108,6 +109,12 @@ HelpMessageDialog::HelpMessageDialog(QWidget *parent, bool about) :
         cursor.movePosition(QTextCursor::NextRow);
         cursor.insertText(tr("UI options") + ":", bold);
         cursor.movePosition(QTextCursor::NextRow);
+        if (GetBoolArg("-help-debug", false)) {
+            cursor.insertText("-allowselfsignedrootcertificates");
+            cursor.movePosition(QTextCursor::NextCell);
+            cursor.insertText(tr("Allow self signed root certificates (default: 0)"));
+            cursor.movePosition(QTextCursor::NextCell);
+        }
         cursor.insertText("-choosedatadir");
         cursor.movePosition(QTextCursor::NextCell);
         cursor.insertText(tr("Choose data directory on startup (default: 0)"));