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 use FileHandle;
  67 use IPC::Open2;
  68
  69 if (scalar(@ARGV) < 3)
  70   {
  71   print "Usage: exim_checkaccess <IP address> <email address> [exim options]\n";
  72   exit(1);
  73   }
  74
  75 $exim_path = $ARGV[0];          # Set up by the calling shell script
  76 $host      = $ARGV[1];          # Mandatory original first argument
  77 $recipient = $ARGV[2];          # Mandatory original second argument
  78
  79 $c4 = qr/2 (?:[0-4]\d | 5[0-5]) | 1\d\d | \d{1,2}/x;  # IPv4 component
  80 $a4 = qr/^$c4\.$c4\.$c4\.$c4$/;                       # IPv4 address
  81
  82 $c6 = qr/[0-9a-f]{1,4}/i;                             # IPv6 component
  83
  84 # Split the various formats of IPv6 addresses into several cases. I don't
  85 # think I can graft regex that matches all of them without using alternatives.
  86
  87 # 1. Starts with :: followed by up to 7 components
  88
  89 $a6_0 = qr/^::(?:$c6:){0,6}$c6$/x;
  90
  91 # 2. 8 non-empty components
  92
  93 $a6_1 = qr/^(?:$c6:){7}$c6$/x;
  94
  95 # 3. This is the cunning one. Up to 7 components, one (and only one) of which
  96 # can be empty. We use 0 to cause a failure when we've already matched
  97 # an empty component and may be hitting other. This has to fail, because we
  98 # know we've just failed to match a component. We also do a final check to
  99 # ensure that there has been an empty component.
 100
 101 $a6_2 = qr/^(?: (?: $c6 | (?(1)0 | () ) ) : ){1,7}$c6 $ (?(1)|.)/x;
 102
 103 if ($host !~ /$a4 | $a6_0 | $a6_1 | $a6_2/x)
 104   {
 105   print "** Invalid IP address \"$host\"\n";
 106   print "Usage: exim_checkaccess <IP address> <email address> [exim options]\n";
 107   exit(1);
 108   }
 109
 110 # Build any remaining original arguments into a string for passing over
 111 # as Exim options.
 112
 113 $opt = "";
 114 for ($i = 3; $i < scalar(@ARGV); $i++) { $opt .= "$ARGV[$i] "; }
 115
 116 # If the string contains "-f xxxx", extract that as the sender. Otherwise
 117 # the sender is <>.
 118
 119 $sender    = "";
 120 if ($opt =~ /(?:^|\s)-f\s+(\S+|"[^"]*")/)
 121   {
 122   $sender = $1;
 123   $opt = $` . $';
 124   }
 125
 126 # Run a -bh test in Exim, passing the test data
 127
 128 $pid = open2(*IN, *OUT, "$exim_path -bh $host $opt 2>/dev/null");
 129 print OUT "HELO [$host]\r\n";
 130 print OUT "MAIL FROM:<$sender>\r\n";
 131 print OUT "RCPT TO:<$recipient>\r\n";
 132 print OUT "QUIT\r\n";
 133 close OUT;
 134
 135 # Read the output, ignoring anything but the SMTP response to the RCPT
 136 # command.
 137
 138 $count = 0;
 139 $reply = "";
 140
 141 while (<IN>)
 142   {
 143   next if !/^\d\d\d/;
 144   $reply .= $_;
 145   next if /^\d\d\d\-/;
 146
 147   if (++$count != 4)
 148     {
 149     $reply = "";
 150     next;
 151     }
 152
 153   # We have the response we want. Interpret it.
 154
 155   if ($reply =~ /^2\d\d/)
 156     {
 157     print "Accepted\n";
 158     }
 159   else
 160     {
 161     print "Rejected:\n";
 162     $reply =~ s/\n(.)/\n  $1/g;
 163     print "  $reply";
 164     }
 165   last;
 166   }
 167
 168 # Reap the child process
 169
 170 waitpid $pid, 0;
 171
 172 End