60 lines
1.3 KiB
Perl
60 lines
1.3 KiB
Perl
#!perl -w
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=head1 NAME
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count_unrecognized_commands - Count unrecognized commands and disconnect when we have too many
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=head1 DESCRIPTION
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Disconnect the client if it sends too many unrecognized commands.
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Good for rejecting spam sent through open HTTP proxies.
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=head1 CONFIGURATION
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Takes one parameter, the number of allowed unrecognized commands
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before we disconnect the client. Defaults to 4.
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=cut
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use strict;
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use warnings;
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use Qpsmtpd::Constants;
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sub register {
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my ($self, $qp ) = shift, shift;
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$self->{_unrec_cmd_max} = shift || 4;
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if ( scalar @_ ) {
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$self->log(LOGWARN, "Ignoring additional arguments.");
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}
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}
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sub hook_connect {
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my $self = shift;
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$self->qp->connection->notes('unrec_cmd_count', 0);
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return DECLINED;
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}
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sub hook_unrecognized_command {
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my ($self, $cmd) = @_[0,2];
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$self->log(LOGINFO, "Unrecognized command '$cmd'");
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my $badcmdcount =
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$self->qp->connection->notes( 'unrec_cmd_count',
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($self->qp->connection->notes('unrec_cmd_count') || 0) + 1
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);
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if ($badcmdcount >= $self->{_unrec_cmd_max}) {
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my $msg = "Closing connection, $badcmdcount unrecognized commands.";
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$self->log(LOGINFO, "fail: $msg");
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return (DENY_DISCONNECT, "$msg Perhaps you should read RFC 2821?");
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}
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return DECLINED;
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}
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