cvs commit: qpsmtpd/plugins check_earlytalker

cvsuser     04/08/01 00:08:07

  Modified:    plugins  check_earlytalker
  Log:
  Incorporate suggestions and part of a patch from Mark Powell:
  - Make the awkward silence at connection configurable (default still 1sec)
  - Add an option to defer reaction to the HELO to the MAIL-FROM command
    instead, anticipating broken SMTP agents that don't gracefully handle
    disconnection after greeting.
  
  Also made the specific response configurable (soft, hard, nothing).
  
  Revision  Changes    Path
  1.3       +76 -15    qpsmtpd/plugins/check_earlytalker
  
  Index: check_earlytalker
  ===================================================================
  RCS file: /cvs/public/qpsmtpd/plugins/check_earlytalker,v
  retrieving revision 1.2
  retrieving revision 1.3
  diff -u -w -r1.2 -r1.3
  --- check_earlytalker	5 Mar 2004 12:46:24 -0000	1.2
  +++ check_earlytalker	1 Aug 2004 07:08:07 -0000	1.3
  @@ -4,28 +4,68 @@
   
   =head1 DESCRIPTION
   
  -Hooks connect, checks to see if the remote host starts talking before
  -we've issued a 2xx greeting.  If so, we're likely looking at a
  -direct-to-MX spam agent which pipelines its entire SMTP conversation,
  -and will happily dump an entire spam into our mail log even if later
  -tests deny acceptance.
  +Checks to see if the remote host starts talking before we've issued a 2xx
  +greeting.  If so, we're likely looking at a direct-to-MX spam agent which
  +pipelines its entire SMTP conversation, and will happily dump an entire spam
  +into our mail log even if later tests deny acceptance.
   
  -Such clients gets a 450 error code.  
  +Depending on configuration, clients which behave in this way are either
  +immediately disconnected with a deny or denysoft code, or else are issued this
  +on all mail/rcpt commands in the transaction.
   
  -=head1 TODO
  +=head1 CONFIGURATION
   
  -Make how long we wait before reading from the socket configurable
  -(currently 1 second)
  +=over 4
   
  -Make the soft/hard response code configurable (currently DENYSOFT)
  +=item wait [integer]
  +
  +The number of seconds to delay the initial greeting to see if the connecting
  +host speaks first.  The default is 1.
  +
  +=item action [string: deny, denysoft, log]
  +
  +What to do when matching an early-talker -- the options are I<deny>,
  +I<denysoft> or I<log>.
  +
  +If I<log> is specified, the connection will be allowed to proceed as normal,
  +and only a warning will be logged.
  +
  +The default is I<denysoft>.
  +
  +=item defer-reject [boolean]
  +
  +When an early-talker is detected, if this option is set to a true value, the
  +SMTP greeting will be issued as usual, but all RCPT/MAIL commands will be
  +issued a deny or denysoft (depending on the value of I<action>).  The default
  +is to react at the SMTP greeting stage by issuing the apropriate response code
  +and terminating the SMTP connection.
  +
  +=back
   
   =cut
   
   use IO::Select;
   
  +use warnings;
  +use strict;
  +
   sub register {
  -  my ($self, $qp) = @_;
  +  my ($self, $qp, @args) = @_;
  +
  +  if (@args % 2) {
  +	$self->log(LOGERROR, "Unrecognized/mismatched arguments");
  +	return undef;
  +  }
  +  $self->{_args} = {
  +  	'wait' => 1,
  +	'action' => 'denysoft',
  +	'defer-reject' => 0,
  +	@args,
  +  };
     $self->register_hook('connect', 'connect_handler');
  +  $self->register_hook('mail', 'mail_handler')
  +    if $self->{_args}->{'defer-reject'};
  +  1;
   }
   
   sub connect_handler {
  @@ -33,10 +73,31 @@
     my $in = new IO::Select;
     
     $in->add(\*STDIN) || return DECLINED;
  -  if ($in->can_read(1)) {
  -    $self->log(LOGDEBUG, "remote host started talking before we said hello");
  -    return (DENYSOFT, "Don't be rude and talk before I say hello!");
  +  if ($in->can_read($self->{_args}->{'wait'})) {
  +    $self->log(LOGNOTICE, 'remote host started talking before we said hello');
  +    if ($self->{_args}->{'defer-reject'}) {
  +	$self->qp->connection->notes('earlytalker', 1);
  +    } else {
  +      my $msg = 'Connecting host started transmitting before SMTP greeting';
  +      return (DENY,$msg) if $self->{_args}->{'action'} eq 'deny';
  +      return (DENYSOFT,$msg) if $self->{_args}->{'action'} eq 'denysoft';
  +    }
  +  } else {
  +    $self->log(LOGINFO, 'remote host said nothing spontaneous, proceeding');
     }
  -  $self->log(LOGINFO,"remote host said nothing spontaneous, proceeding");
     return DECLINED;
   }
  +
  +sub mail_handler {
  +  my ($self, $txn) = @_;
  +  my $msg = 'Connecting host started transmitting before SMTP greeting';
  +
  +  return DECLINED unless $self->qp->connection->notes('earlytalker');
  +  return (DENY,$msg) if $self->{_args}->{'action'} eq 'deny';
  +  return (DENYSOFT,$msg) if $self->{_args}->{'action'} eq 'denysoft';
  +  return DECLINED;
  +}
  +
  +
  +1;
  +