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