Using SecureSMTPClientSession with GMail

[peterk]

Hi all,

I am trying to send an e-mail through GMail's smtp severs. They require authentication, so I am using SecureSMTPClientSession. Here is the code:

Code: Select all

Poco::Net::MailMessage message;
   message.setSender("sender@sender.com");
   message.addRecipient(Poco::Net::MailRecipient(Poco::Net::MailRecipient::PRIMARY_RECIPIENT, "blah@blah.blah", "Blah Blaherson"));
   message.setSubject("Test Message");
   message.setContent("Hello\r\nblah blah\r\n\r\nJohn\r\n");

   Poco::Net::SecureSMTPClientSession session("smtp.gmail.com",587);
   session.login("smtp.gmail.com");
   session.startTLS();
   session.login("smtp.gmail.com",Poco::Net::SMTPClientSession::AUTH_LOGIN,"gmail_account","gmail_password");
   session.sendMessage(message);

Everything compiles without any errors or warnings, but the code segfaults on session.startTLS(). What am I doing wrong? Has anybody on this forum done this before?

Thanks,
P.

[guenter]

You'll either need to create a Poco::Net::Context object (for client use) and pass it to startTLS(), or use the Util application framework (Poco::Util::Application or Poco::Util::ServerApplication) and create a configuration file with an appropriate OpenSSL configuration.

See the download sample in the NetSSL_OpenSSL/samples directory for how to perform proper NetSSL initialization and for how to create the Context object.

[peterk]

Sorry, I still can't figure out how to do it. Can you provide some example code applicable to this case, using Poco::Net::Context?

[guenter]

Here's the Mail sample from Net modified to work with SecureSMTPClientSession. Tested with gmail. Note that you need to call login() twice. Once without credentials, the second time (after switching to a secure connection) with your username and password.

Code: Select all

#include "Poco/Net/MailMessage.h"
#include "Poco/Net/MailRecipient.h"
#include "Poco/Net/SecureSMTPClientSession.h"
#include "Poco/Net/StringPartSource.h"
#include "Poco/Net/SSLManager.h"
#include "Poco/Net/KeyConsoleHandler.h"
#include "Poco/Net/ConsoleCertificateHandler.h"
#include "Poco/SharedPtr.h"
#include "Poco/Path.h"
#include "Poco/Exception.h"
#include <iostream>


using Poco::Net::MailMessage;
using Poco::Net::MailRecipient;
using Poco::Net::SMTPClientSession;
using Poco::Net::SecureSMTPClientSession;
using Poco::Net::StringPartSource;
using Poco::Net::SSLManager;
using Poco::Net::Context;
using Poco::Net::KeyConsoleHandler;
using Poco::Net::PrivateKeyPassphraseHandler;
using Poco::Net::InvalidCertificateHandler;
using Poco::Net::ConsoleCertificateHandler;
using Poco::SharedPtr;
using Poco::Path;
using Poco::Exception;


class SSLInitializer
{
public:
   SSLInitializer()
   {
      Poco::Net::initializeSSL();
   }
   
   ~SSLInitializer()
   {
      Poco::Net::uninitializeSSL();
   }
};


const unsigned char PocoLogo[] =
{
   #include "PocoLogo.hpp"
};


int main(int argc, char** argv)
{
   SSLInitializer sslInitializer;

   if (argc != 4)
   {
      Path p(argv[0]);
      std::cerr << "usage: " << p.getBaseName() << " <mailhost> <sender> <recipient>" << std::endl;
      std::cerr << "       Send an email greeting from <sender> to <recipient>," << std::endl;
      std::cerr << "       the SMTP server at <mailhost>." << std::endl;
      return 1;
   }
   
   std::string mailhost(argv[1]);
   std::string sender(argv[2]);
   std::string recipient(argv[3]);
   
   try
   {
      // Note: we must create the passphrase handler prior Context
      SharedPtr<InvalidCertificateHandler> pCert = new ConsoleCertificateHandler(false); // ask the user via console
      Context::Ptr pContext = new Context(Context::CLIENT_USE, "", "", "", Context::VERIFY_RELAXED, 9, true, "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH");
      SSLManager::instance().initializeClient(0, pCert, pContext);

      MailMessage message;
      message.setSender(sender);
      message.addRecipient(MailRecipient(MailRecipient::PRIMARY_RECIPIENT, recipient));
      message.setSubject("Hello from the POCO C++ Libraries");
      std::string content;
      content += "Hello ";
      content += recipient;
      content += ",\r\n\r\n";
      content += "This is a greeting from the POCO C++ Libraries.\r\n\r\n";
      std::string logo(reinterpret_cast<const char*>(PocoLogo), sizeof(PocoLogo));
      message.addContent(new StringPartSource(content));
      message.addAttachment("logo", new StringPartSource(logo, "image/gif"));
      
      SecureSMTPClientSession session(mailhost);
      session.login();
      session.startTLS(pContext);
      session.login(SMTPClientSession::AUTH_LOGIN, "username", "password");
      session.sendMessage(message);
      session.close();
   }
   catch (Exception& exc)
   {
      std::cerr << exc.displayText() << std::endl;
      return 1;
   }
   return 0;
}


[peterk]

Thank you!

[vortex]

The following code worked fine for me. But I would like to store the certificate on a location on disk (on a trusted list location), and then use this code to send an email without the console handler getting called, therefore i modified your code in the following manner:

Code: Select all

...
Context::Ptr pContext = new Context(Context::CLIENT_USE, "", "", "C:\\TrustedCertificates\\", Context::VERIFY_RELAXED, 9, true, "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH");
..


And i have saved the gmail certificate as a .pem file in the path "C:\\TrustedCertificates\\", but still, i got an invalid certificate handler call.
What is the way to resolve this?
My final aim would be to save new certificates in an untrusted location on disk (i guess this could be handled with an InvalidCertificateHandler implementation) and check the trusted certificates from a trusted location.
Is there a way to bring this about?