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POE::Filter::SSL(3pm) User Contributed Perl Documentation POE::Filter::SSL(3pm)

NAME

POE::Filter::SSL - The easiest and flexiblest way to SSL in POE!

VERSION

Version 0.41

DESCRIPTION

This module allows one to secure connections of POE::Wheel::ReadWrite with OpenSSL by a POE::Filter object, and behaves (beside of SSLing) as POE::Filter::Stream.

POE::Filter::SSL can be added, switched and removed during runtime, for example if you want to initiate SSL (see the SSL on an established connection example in SYNOPSIS) on an already established connection. You are able to combine POE::Filter::SSL with other filters, for example have a HTTPS server together with POE::Filter::HTTPD (see the HTTPS-Server example in SYNOPSIS).

POE::Filter::SSL is based on Net::SSLeay, but got two XS functions which Net::SSLeay is missing.

Features
Full non-blocking processing

No use of sockets at all

Server and client mode

Optional client certificate verification

Allows one to accept connections with invalid or missing client certificate and return custom error data

CRL check of client certificates

Retrieve client certificate details (subject name, issuer name, certificate serial)

Upcoming Features
Direct cipher encryption without SSL or TLS protocol, for example with static AES encryption

SYNOPSIS

By default POE::Filter::SSL acts as a SSL server. To use it in client mode you just have to set the client option of new() .
TCP-Client
  #!perl

  use warnings;
  use strict;

  use POE qw(Component::Client::TCP Filter::SSL);

  POE::Component::Client::TCP->new(
    RemoteAddress => "yahoo.com",
    RemotePort    => 443,
    Filter        => [ "POE::Filter::SSL", client => 1 ],
    Connected     => sub {
      $_[HEAP]{server}->put("HEAD /\r\n\r\n");
    },
    ServerInput   => sub {
      print "from server: ".$_[ARG0]."\n";
    },
  );

  POE::Kernel->run();
  exit;
    
TCP-Server
  #!perl

  use warnings;
  use strict;

  use POE qw(Component::Server::TCP);

  POE::Component::Server::TCP->new(
    Port => 443,
    ClientFilter => [ "POE::Filter::SSL", crt => 'server.crt', key => 'server.key' ],
    ClientConnected => sub {
      print "got a connection from $_[HEAP]{remote_ip}\n";
      $_[HEAP]{client}->put("Smile from the server!\r\n");
    },
    Alias => "tcp",
    ClientInput => sub {
      my ($kernel, $session, $heap) = @_[KERNEL, SESSION, HEAP];
      $_[HEAP]{client}->put("You sent:\r\n".$_[ARG0]);
      $_[KERNEL]->yield("shutdown");
    },
  );

  POE::Kernel->run;
  exit;
    
HTTPS-Server
  use POE::Filter::SSL::PreFilter
  use POE::Filter::SSL;
  use POE::Component::Server::HTTP;
  use HTTP::Status;
  my $aliases = POE::Component::Server::HTTP->new(
    Port => 443,
    ContentHandler => {
      '/' => \&handler,
      '/dir/' => sub { return; },
      '/file' => sub { return; }
    },
    Headers => { Server => 'My Server' },
    PreFilter => POE::Filter::SSL->new(
      crt    => 'server.crt',
      key    => 'server.key',
      cacrt  => 'ca.crt'
    )
  );

  sub handler {
    my ($request, $response) = @_;
    $response->code(RC_OK);
    $response->content("Hi, you fetched ". $request->uri);
    return RC_OK;
  }

  POE::Kernel->run();
  POE::Kernel->call($aliases->{httpd}, "shutdown");
  # next line isn't really needed
  POE::Kernel->call($aliases->{tcp}, "shutdown");
    

SSL on an established connection

Advanced Example
This example is an IMAP-Relay which forwards the connections to a IMAP server by username. It allows one the unencrypted transfer on port 143, with the option of SSL on the established connection (STARTTLS). On port 993 it allows one to do direct SSL.

Tested with Thunderbird version 3.0.5.

  #!perl

  use warnings;
  use strict;

  use POE qw(Component::Server::TCP Component::Client::TCP Filter::SSL Filter::Stream);

  my $defaultImapServer = "not.existing.de";
  my $usernameToImapServer = {
    user1 => 'mailserver1.domain.de',
    user2 => 'mailserver2.domain.de',
    # ...
  };

  POE::Component::Server::TCP->new(
    Port => 143,
    ClientFilter => "POE::Filter::Stream",
    ClientDisconnected => \&disconnect,
    ClientConnected => \&connected,
    ClientInput => \&handleInput,
    InlineStates => {
      send_stuff => \&send_stuff,
      _child => \&child
    }
  );

  POE::Component::Server::TCP->new(
    Port => 993,
    ClientFilter => [ "POE::Filter::SSL", crt => 'server.crt', key => 'server.key' ],
    ClientConnected => \&connected,
    ClientDisconnected => \&disconnect,
    ClientInput => \&handleInput,
    InlineStates => {
      send_stuff => \&send_stuff,
      _child => \&child
    }
  );

  sub disconnect {
    my ($kernel, $session, $heap) = @_[KERNEL, SESSION, HEAP];
    logevent('server got disconnect', $session);
    $kernel->post($heap->{client_id} => "shutdown");
  }

  sub connected {
    my ($kernel, $session, $heap) = @_[KERNEL, SESSION, HEAP];
    logevent("got a connection from ".$heap->{remote_ip}, $session);
    $heap->{client}->put("* OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] IMAP Relay v0.1 ready.\r\n");
  }

  sub send_stuff {
    my ($heap, $stuff, $session) = @_[HEAP, ARG0, SESSION];
    logevent("-> ".length($stuff)." Bytes", $session);
    (defined($heap->{client})) && (ref($heap->{client}) eq "POE::Wheel::ReadWrite") &&
    $heap->{client}->put($stuff);
  }

  sub child {
    my ($heap, $child_op, $child) = @_[HEAP, ARG0, ARG1];
    if ($child_op eq "create") {
      $heap->{client_id} = $child->ID;
    }
  }

  sub handleInput {
    my ($kernel, $session, $heap, $input) = @_[KERNEL, SESSION, HEAP, ARG0];
    if($heap->{forwarding}) {
      return $kernel->yield("shutdown") unless (defined($heap->{client_id}));
      $kernel->post($heap->{client_id} => send_stuff => $input);
    } elsif ($input =~ /^(\d+)\s+STARTTLS[\r\n]+/i) {
      $_[HEAP]{client}->put($1." OK Begin SSL/TLS negotiation now.\r\n");
      logevent("SSLing now...", $session);
      $_[HEAP]{client}->set_filter(POE::Filter::SSL->new(crt => 'server.crt', key => 'server.key'));
    } elsif ($input =~ /^(\d+)\s+CAPABILITY[\r\n]+/i) {
      $_[HEAP]{client}->put("* CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS\r\n");
      $_[HEAP]{client}->put($1." OK CAPABILITY completed\r\n");
    } elsif ($input =~ /^(\d+)\s+login\s+\"(\S+)\"\s+\"(\S+)\"[\r\n]+/i) {
      my $username = $2;
      my $pass = $3;
      logevent("login of user ".$username, $session);
      spawn_client_side($username, $input);
      $heap->{forwarding}++;
    } else {
      logevent("unknown command before login, disconnecting.", $session);
      return $kernel->yield("shutdown");
    }
  }

  sub spawn_client_side {
    my $username = shift;
    POE::Component::Client::TCP->new(
      RemoteAddress => $usernameToImapServer->{$username} || $defaultImapServer,
      RemotePort    => 143,
      Filter => "POE::Filter::Stream",
      Started       => sub {
        $_[HEAP]->{server_id} = $_[SENDER]->ID;
        $_[HEAP]->{buf} = $_[ARG0];
        $_[HEAP]->{skip} = 0;
      },
      Connected => sub {
        my ($heap, $session) = @_[HEAP, SESSION];
        logevent('client connected', $session);
        $heap->{server}->put($heap->{buf});
        delete $heap->{buf};
      },
      ServerInput => sub {
        my ($kernel, $heap, $session, $input) = @_[KERNEL, HEAP, SESSION, ARG0];
        #logevent('client got input', $session, $input);
        $kernel->post($heap->{server_id} => send_stuff => $input) if ($heap->{skip}++);
      },
      Disconnected => sub {
        my ($kernel, $heap, $session) = @_[KERNEL, HEAP, SESSION];
        logevent('client disconnected', $session);
        $kernel->post($heap->{server_id} => 'shutdown');
      },
      InlineStates => {
        send_stuff => sub {
          my ($heap, $stuff, $session) = @_[HEAP, ARG0, SESSION];
          logevent("<- ".length($stuff)." Bytes", $session);
          (defined($heap->{server})) && (ref($heap->{server}) eq "POE::Wheel::ReadWrite") && 
          $heap->{server}->put($stuff);
        },
      },
      Args => [ shift ]
    );
  }

  sub logevent {
    my ($state, $session, $arg) = @_;
    my $id = $session->ID();
    print "session $id $state ";
    print ": $arg" if (defined $arg);
    print "\n";
  }

  POE::Kernel->run;
    

Client certificate verification

Advanced Example
The following example implements a HTTPS server with client certificate verification, which shows details about the verified client certificate.

  #!perl

  use strict;
  use warnings;
  use Socket;
  use POE qw(
    Wheel::SocketFactory
    Wheel::ReadWrite
    Driver::SysRW
    Filter::SSL
    Filter::Stackable
    Filter::HTTPD
  );

  POE::Session->create(
    inline_states => {
      _start       => sub {
        my $heap = $_[HEAP];
        $heap->{listener} = POE::Wheel::SocketFactory->new(
          BindAddress  => '0.0.0.0',
          BindPort     => 443,
          Reuse        => 'yes',
          SuccessEvent => 'socket_birth',
          FailureEvent => '_stop',
        );
      },
      _stop => sub {
        delete $_[HEAP]->{listener};
      },
      socket_birth => sub {
        my ($socket) = $_[ARG0];
        POE::Session->create(
          inline_states => {
            _start       => sub {
              my ($heap, $kernel, $connected_socket, $address, $port) = @_[HEAP, KERNEL, ARG0, ARG1, ARG2];
              $heap->{sslfilter} = POE::Filter::SSL->new(
                 crt    => 'server.crt',
                 key    => 'server.key',
                 cacrt  => 'ca.crt',
                 cipher => 'DHE-RSA-AES256-GCM-SHA384:AES256-SHA',
                 #cacrl  => 'ca.crl', # Uncomment this, if you have a CRL file.
                 debug  => 1,
                 clientcert => 1
              );
              $heap->{socket_wheel} = POE::Wheel::ReadWrite->new(
                Handle     => $connected_socket,
                Driver     => POE::Driver::SysRW->new(),
                Filter     => POE::Filter::Stackable->new(Filters => [
                  $heap->{sslfilter},
                  POE::Filter::HTTPD->new()
                ]),
                InputEvent => 'socket_input',
                ErrorEvent => '_stop',
              );
            },
            socket_input => sub {
              my ($kernel, $heap, $buf) = @_[KERNEL, HEAP, ARG0];
              my (@certid) = ($heap->{sslfilter}->clientCertIds());
              my $content = '';
              if ($heap->{sslfilter}->clientCertValid()) {
                $content .= "Hello <font color=green>valid</font> client Certifcate:";
              } else {
                $content .= "None or <font color=red>invalid</font> client certificate:";
              }
              $content .= "<hr>";
              foreach my $certid (@certid) {
                $certid = $certid ? $certid->[0]."<br>".$certid->[1]."<br>SERIAL=".$heap->{sslfilter}->hexdump($certid->[2]) : 'No client certificate';
                $content .= $certid."<hr>";
              }
              $content .= "Your URL was: ".$buf->uri."<hr>"
                if (ref($buf) eq "HTTP::Request");
              $content .= localtime(time());
              my $response = HTTP::Response->new(200);
              $response->push_header('Content-type', 'text/html');
              $response->content($content);
              $heap->{socket_wheel}->put($response);
              $kernel->delay(_stop => 1);
            },
            _stop => sub {
              delete $_[HEAP]->{socket_wheel};
            }
          },
          args => [$socket],
        );
      }
    }
  );

  $poe_kernel->run();
    

FUNCTIONS

new(option = value, option => value, option...)>
Returns a new POE::Filter::SSL object. It accepts the following options:
client
By default POE::Filter::SSL acts as a SSL server. To use it in client mode, you have to set this option.
crt{mem}
The certificate file (.crt) for the server, a client certificate in client mode.

You are able to pass the already inmemory crt file as scalar via crtmem.

key{mem}
The key file (.key) of the certificate (see crt above).

You are able to pass the already inmemory key file as scalar via keymem.

cacrt{mem}
The ca certificate file (ca.crt), which is used to verificate the client certificates against a CA. You can store multiple ca in one file, all of them gets imported.

You are able to pass the already inmemory cacrt file as scalar via cacrtmem or as an array ref of scalars, if you have multiple ca.

caverifydepth
By default the ca verify depth is 5, you can override this via this option.
chain
Chain certificate, you need it for example for startssl.org which needs a intermedia certificates. Here you can configure it. You can generate this the following way:

cat client.crt intermediate.crt ca.crt > chain.pem

In this case, you normalyly have no key and crt option. Currently it is not possible to pass this inmemory, only by file.

cacrl
Configures a CRL (ca.crl) against the client certificate is verified by clientCertValid().
dhcert{mem}
If you want to enable perfect forward secrecy, here you can enable Diffie-Hellman. You just have to create a dhparam file and there here the path to the path/to/FILENAME.pem where your Diffie-Hellman (pem format) stays.

openssl dhparam -check -text -5 2048 -out path/to/FILENAME.pem

You are able to pass the already inmemory dhparam file as scalar(string) via dhcertmem.

clientcert
Only in server mode: Request during ssl handshake from the client a client certificate.

WARNING: If the client provides an untrusted or no client certificate, the connection is not failing. You have to ask clientCertValid() if the certificate is valid!

sni
Allows one to set the SNI hostname indication in first packet of handshake. See https://de.wikipedia.org/wiki/Server_Name_Indication
tls
Force in the handshake the use of tls, disables support for the obsolete SSL handshake.
tls1_2
Force in the handshake the use of tls in version 1.2, disables support for the obsolete SSL handshake.
nohonor
By default, as server, POE::Filter:SSL sets the option SSL_OP_CIPHER_SERVER_PREFERENCE. For more information you may google the pendant of apache SSLHonorCipherOrder.

To flip back to the old behaviour, not setting this option, you can set nohonor.

cipher
Specify which ciphers are allowed for the synchronous encrypted transfer of the data over the ssl connection.

Example:

  cipher => 'DHE-RSA-AES256-GCM-SHA384:AES256-SHA'
    
blockbadclientcert
Let OpenSSL deny the connection if there is no client certificate.

WARNING: If the client is listed in the CRL file or an invalid client certifiate has been sent, the connection will be established! You have to ask clientCertValid() if you have the crl option set on new(), otherwise to ask clientCertNotOnCRL() if the certificate is listed on your CRL file!

ignoreVerifyErrors
WARNING: Before using this option, you should be realy sure that you know what you are doing!

Specify to ignore specific errors on verifying the certificate chain: This is for example useful to be able to fetch the time from via secure and trusted TLS connection. In this case, your time is wrong, so must ignore time errors, which are 9: X509_V_ERR_CERT_NOT_YET_VALID (certificate is not yet valid) and 10: X509_V_ERR_CERT_HAS_EXPIRED (certificate has expired).

The list of errors you can ignore can be found on the documentation:

<https://wiki.openssl.org/index.php/Manual:Verify(1)>

Example:

  ignoreVerifyErrors => [ 9, 10, ]
    
handshakeDone(options)
Returns true if the handshake is done and all data for handshake has been written out. It accepts the following options:
ignorebuf
Returns true if OpenSSL has established the connection, regardless if all data has been written out. This is needed if you want to exchange the Filter of POE::Wheel::ReadWrite before the first data comes in. This option have been only used by doHandshake() to be able to add new filters before first cleartext data to be processed gets in.
clientCertNotOnCRL($file)
Verifies if the serial of the client certificate is not contained in the CRL $file. No file caching is done, each call opens the file again.

WARNING: If your CRL file is missing, can not be opened is empty or has no blocked certificate at all in it, then every call will get blocked!

clientCertIds()
Returns an array of every certificate found by OpenSSL. Each element is again a array. The first element is the value of X509_get_subject_name, second is the value of X509_get_issuer_name and third element is the serial of the certificate in binary form. You have to use split() and ord(), or the hexdump() function, to convert it to a readable form.

Example:

  my ($certid) = ($heap->{sslfilter}->clientCertIds());
  $certid = $certid ? $certid->[0]."<br>".$certid->[1]."<br>SERIAL=".$heap->{sslfilter}->hexdump($certid->[2]) : 'No client certificate';
    
getCipher()
Returns the used cryptographic algorithm and length.

Example:

  $sslfilter->getCipher()
    
clientCertValid()
Returns true if there is a client certificate that is valid. It also tests against the CRL, if you have the cacrl option set on new().
doHandshake($readWrite, $filter, $filter, ...) !!!REMOVED!!!
WARNING: POE::Filter:SSL now is able to do the ssh handshake now without any helpers. Because of this, this function has been removed!

Allows one to add filters after the ssl handshake. It has to be called in the input handler, and needs the passing of the POE::Wheel::ReadWhile object. If it returns false, you have to return from the input handler.

See the HTTPS-Server, SSL on an established connection and Client certificate verification examples in SYNOPSIS

clientCertExists()
Returns true if there is a client certificate, that might be untrusted.

WARNING: If the client provides an untrusted client certificate a client certificate that is listed in CRL, this function returns true. You have to ask clientCertValid() if the certificate is valid!

errorhandler
By default, every ssl error is escalated via carp. You may change this behaviour via this option to:
"ignore"
Do not report any error.
CODE
Setting errorhandler to a reference of a function allows one to be called it callback function with the following options:

ARG1: POE:SSL::Filter instance

ARG2: Ref on a Hash with the following keys:

  ret        The return code of Net::SSLeay::connect (client) or Net::SSLeay::accept (server)
  ssl        The SSL context (SSL_CTX)
  msg        The error message as text, as normally reported via carp
  get_error  The error code of get_error the ssl context
  error      The error code of get_error without context
    
"carp" (or undef)
Do Carp/carp on error.
"confess"
Do Carp/confess (stacktrace) on error.
"carponetime"
Report carp for one occurrence only one time - over all!
debug
Shows debug messages of clientCertNotOnCRL().
hexdump($string)
Returns string data in hex format.

Example:

  perl -e 'use POE::Filter::SSL; print POE::Filter::SSL->hexdump("test")."\n";'
  74:65:73:74
    

Internal functions and POE::Filter handler

VERIFY()
POE_FILTER_X509_get_serialNumber()
POE_FILTER_SSL_CTX_set_tmp_dh()
POE_FILTER_SSL_CTX_set_tmp_rsa()
POE_FILTER_SSL_set_tmp_dh()
clone()
doSSL()
get()
get_one()
get_one_start()
get_pending()
writeToSSLBIO()
writeToSSL()
put()
verify_serial_against_crl_file()
DOSENDBACK()
checkForDoSendback()
CTX_add_client_CA()
PEMdataToEVP_PKEY
PEMdataToX509
dataToBio

AUTHOR

Markus Schraeder, "<privi at cpan.org>"

BUGS

Please report any bugs or feature requests to "bug-poe-filter-ssl at rt.cpan.org", or through the web interface at <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=POE-Filter-SSL>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc POE::Filter::SSL

You can also look for information at:

Commercial support

Commercial support can be gained at <sslsupport at cryptomagic.eu>.

Used in our products, you can find on <https://www.cryptomagic.eu/>

COPYRIGHT & LICENSE

Copyright 2010-2017 Markus Schraeder, CryptoMagic GmbH, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

2019-10-06 perl v5.30.0