131 lines
3.2 KiB
Perl
Executable File
131 lines
3.2 KiB
Perl
Executable File
#!/usr/bin/perl
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###################################################################
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# identd.perl5 : An implementation of RFC 1413 Ident Server
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# using Vic Abell's lsof.
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#
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# - Started from inetd with 'nowait' option. This entry in
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# /etc/inetd.conf will suffice :
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#
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# ident stream tcp nowait root /usr/local/bin/identd.perl5 -t200
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#
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# - Multiple instances of the server are not a performance penalty
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# since they shall use lsof's cacheing mechanism. (compare with
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# Peter Eriksson's pidentd)
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# - assumes 'lsof' binary in $PATH
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# - Command line arguments :
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# -t TIMEOUT Number of seconds to wait for a query before aborting.
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# Default is 120.
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#
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# Kapil Chowksey <kchowksey@hss.hns.com>
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###################################################################
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use strict;
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use Socket;
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use Getopt::Long;
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# Set path to lsof.
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my $LSOF;
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if (($LSOF = &isexec("/usr/bin/lsof")) eq "") { # Try .. first
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if (($LSOF = &isexec("lsof")) eq "") { # Then try . and $PATH
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print "can't execute $LSOF\n"; exit 1
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}
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}
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# redirect lsof's warnings/errors to /dev/null
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close(STDERR);
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open(STDERR, ">/dev/null");
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my $Timeout = "120";
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GetOptions('timeout=i'=>\$Timeout);
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my ($port, $iaddr) = sockaddr_in(getpeername(STDIN));
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my $peer_addr = inet_ntoa($iaddr);
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my $query;
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# read ident-query from socket (STDIN) with a timeout.
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my $timeout = int($Timeout);
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eval {
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local $SIG{ALRM} = sub { die "alarm\n" };
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alarm $timeout;
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$query = <STDIN>;
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alarm 0;
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};
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die if $@ && $@ ne "alarm\n";
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if ($@) {
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# timed out
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exit;
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}
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# remove all white-spaces from query
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$query =~ s/\s//g;
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my $serv_port = "";
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my $cli_port = "";
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($serv_port,$cli_port) = split(/,/,$query);
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if ($serv_port =~ /^[0-9]+$/) {
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if (int($serv_port) < 1 || int($serv_port) > 65535) {
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print $query." : ERROR : INVALID-PORT"."\n";
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exit;
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}
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} else {
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print $query." : ERROR : INVALID-PORT"."\n";
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exit;
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}
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if ($cli_port =~ /^[0-9]+$/) {
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if (int($cli_port) < 1 || int($cli_port) > 65535) {
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print $query." : ERROR : INVALID-PORT"."\n";
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exit;
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}
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} else {
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print $query." : ERROR : INVALID-PORT"."\n";
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exit;
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}
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open(LSOFP,"$LSOF -nPDi -T -FLn -iTCP@".$peer_addr.":".$cli_port."|");
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my $user = "UNKNOWN";
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while (my $a_line = <LSOFP>) {
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# extract user name.
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if ($a_line =~ /^L.*/) {
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($user) = ($a_line =~ /^L(.*)/);
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}
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# make sure local port matches.
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if ($a_line =~ /^n.*:\Q$serv_port->/) {
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print $serv_port.", ".$cli_port." : USERID : UNIX :".$user."\n";
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exit;
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}
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}
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print $serv_port.", ".$cli_port." : ERROR : NO-USER"."\n";
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## isexec($path) -- is $path executable
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#
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# $path = absolute or relative path to file to test for executabiity.
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# Paths that begin with neither '/' nor '.' that arent't found as
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# simple references are also tested with the path prefixes of the
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# PATH environment variable.
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sub
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isexec {
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my ($path) = @_;
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my ($i, @P, $PATH);
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$path =~ s/^\s+|\s+$//g;
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if ($path eq "") { return(""); }
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if (($path =~ m#^[\/\.]#)) {
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if (-x $path) { return($path); }
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return("");
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}
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$PATH = $ENV{PATH};
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@P = split(":", $PATH);
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for ($i = 0; $i <= $#P; $i++) {
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if (-x "$P[$i]/$path") { return("$P[$i]/$path"); }
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}
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return("");
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}
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