src/src/exim_checkaccess.src

   1 #! /bin/sh
   2
   3 # Copyright (c) University of Cambridge, 1995 - 2007
   4 # See the file NOTICE for conditions of use and distribution.
   5
   6 # Except when they appear in comments, the following placeholders in this
   7 # source are replaced when it is turned into a runnable script:
   8 #
   9 # CONFIGURE_FILE_USE_NODE
  10 # CONFIGURE_FILE
  11 # BIN_DIRECTORY
  12 # PERL_COMMAND
  13
  14 # PROCESSED_FLAG
  15
  16 # A shell+perl wrapper script to run an automated -bh test to check out
  17 # ACLs for incoming addresses.
  18
  19 # Save the shell arguments because we are going to need the shell variables
  20 # while sorting out the configuration file.
  21
  22 args="$@"
  23
  24 # See if this installation is using the esoteric "USE_NODE" feature of Exim,
  25 # in which it uses the host's name as a suffix for the configuration file name.
  26
  27 if [ "CONFIGURE_FILE_USE_NODE" = "yes" ]; then
  28   hostsuffix=.`uname -n`
  29 fi
  30
  31 # Now find the configuration file name. This has got complicated because
  32 # CONFIGURE_FILE may now be a list of files. The one that is used is the first
  33 # one that exists. Mimic the code in readconf.c by testing first for the
  34 # suffixed file in each case.
  35
  36 set `awk -F: '{ for (i = 1; i <= NF; i++) print $i }' <<End
  37 CONFIGURE_FILE
  38 End
  39 `
  40 while [ "$config" = "" -a $# -gt 0 ] ; do
  41   if [ -f "$1$hostsuffix" ] ; then
  42     config="$1$hostsuffix"
  43   elif [ -f "$1" ] ; then
  44     config="$1"
  45   fi
  46   shift
  47 done
  48
  49 # Search for an exim_path setting in the configure file; otherwise use the bin
  50 # directory. BEWARE: a tab character is needed in the command below. It has had
  51 # a nasty tendency to get lost in the past. Use a variable to hold a space and
  52 # a tab to keep the tab in one place.
  53
  54 exim_path=`perl -ne 'chop;if (/^\s*exim_path\s*=\s*(.*)/){print "$1\n";last;}' $config`
  55 if test "$exim_path" = ""; then exim_path=BIN_DIRECTORY/exim; fi
  56
  57
  58 #########################################################################
  59
  60
  61 # Now run the perl script, passing in the Exim path and the arguments given
  62 # to the overall script.
  63
  64 PERL_COMMAND - $exim_path $args <<'End'
  65
  66 BEGIN { pop @INC if $INC[-1] eq '.' };
  67 use FileHandle;
  68 use IPC::Open2;
  69
  70 if (scalar(@ARGV) < 3)
  71   {
  72   print "Usage: exim_checkaccess <IP address> <email address> [exim options]\n";
  73   exit(1);
  74   }
  75
  76 $exim_path = $ARGV[0];          # Set up by the calling shell script
  77 $host      = $ARGV[1];          # Mandatory original first argument
  78 $recipient = $ARGV[2];          # Mandatory original second argument
  79
  80 $c4 = qr/2 (?:[0-4]\d | 5[0-5]) | 1\d\d | \d{1,2}/x;  # IPv4 component
  81 $a4 = qr/^$c4\.$c4\.$c4\.$c4$/;                       # IPv4 address
  82
  83 $c6 = qr/[0-9a-f]{1,4}/i;                             # IPv6 component
  84
  85 # Split the various formats of IPv6 addresses into several cases. I don't
  86 # think I can graft regex that matches all of them without using alternatives.
  87
  88 # 1. Starts with :: followed by up to 7 components
  89
  90 $a6_0 = qr/^::(?:$c6:){0,6}$c6$/x;
  91
  92 # 2. 8 non-empty components
  93
  94 $a6_1 = qr/^(?:$c6:){7}$c6$/x;
  95
  96 # 3. This is the cunning one. Up to 7 components, one (and only one) of which
  97 # can be empty. We use 0 to cause a failure when we've already matched
  98 # an empty component and may be hitting other. This has to fail, because we
  99 # know we've just failed to match a component. We also do a final check to
 100 # ensure that there has been an empty component.
 101
 102 $a6_2 = qr/^(?: (?: $c6 | (?(1)0 | () ) ) : ){1,7}$c6 $ (?(1)|.)/x;
 103
 104 if ($host !~ /$a4 | $a6_0 | $a6_1 | $a6_2/x)
 105   {
 106   print "** Invalid IP address \"$host\"\n";
 107   print "Usage: exim_checkaccess <IP address> <email address> [exim options]\n";
 108   exit(1);
 109   }
 110
 111 # Build any remaining original arguments into a string for passing over
 112 # as Exim options.
 113
 114 $opt = "";
 115 for ($i = 3; $i < scalar(@ARGV); $i++) { $opt .= "$ARGV[$i] "; }
 116
 117 # If the string contains "-f xxxx", extract that as the sender. Otherwise
 118 # the sender is <>.
 119
 120 $sender    = "";
 121 if ($opt =~ /(?:^|\s)-f\s+(\S+|"[^"]*")/)
 122   {
 123   $sender = $1;
 124   $opt = $` . $';
 125   }
 126
 127 # Run a -bh test in Exim, passing the test data
 128
 129 $pid = open2(*IN, *OUT, "$exim_path -bh $host $opt 2>/dev/null");
 130 print OUT "HELO [$host]\r\n";
 131 print OUT "MAIL FROM:<$sender>\r\n";
 132 print OUT "RCPT TO:<$recipient>\r\n";
 133 print OUT "QUIT\r\n";
 134 close OUT;
 135
 136 # Read the output, ignoring anything but the SMTP response to the RCPT
 137 # command.
 138
 139 $count = 0;
 140 $reply = "";
 141
 142 while (<IN>)
 143   {
 144   next if !/^\d\d\d/;
 145   $reply .= $_;
 146   next if /^\d\d\d\-/;
 147
 148   if (++$count != 4)
 149     {
 150     $reply = "";
 151     next;
 152     }
 153
 154   # We have the response we want. Interpret it.
 155
 156   if ($reply =~ /^2\d\d/)
 157     {
 158     print "Accepted\n";
 159     }
 160   else
 161     {
 162     print "Rejected:\n";
 163     $reply =~ s/\n(.)/\n  $1/g;
 164     print "  $reply";
 165     }
 166   last;
 167   }
 168
 169 # Reap the child process
 170
 171 waitpid $pid, 0;
 172
 173 End