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 $INC[-1] eq '.' };
  67 use FileHandle;
  68 use File::Basename;
  69 use IPC::Open2;
  70
  71 if ($ARGV[0] eq '--version') {
  72     print basename($0) . ": $0\n",
  73           "build: EXIM_RELEASE_VERSIONEXIM_VARIANT_VERSION\n",
  74           "perl(runtime): $]\n";
  75           exit 0;
  76 }
  77
  78 if (scalar(@ARGV) < 3)
  79   {
  80   print "Usage: exim_checkaccess <IP address> <email address> [exim options]\n";
  81   exit(1);
  82   }
  83
  84 $exim_path = $ARGV[0];          # Set up by the calling shell script
  85 $host      = $ARGV[1];          # Mandatory original first argument
  86 $recipient = $ARGV[2];          # Mandatory original second argument
  87
  88 $c4 = qr/2 (?:[0-4]\d | 5[0-5]) | 1\d\d | \d{1,2}/x;  # IPv4 component
  89 $a4 = qr/^$c4\.$c4\.$c4\.$c4$/;                       # IPv4 address
  90
  91 $c6 = qr/[0-9a-f]{1,4}/i;                             # IPv6 component
  92
  93 # Split the various formats of IPv6 addresses into several cases. I don't
  94 # think I can graft regex that matches all of them without using alternatives.
  95
  96 # 1. Starts with :: followed by up to 7 components
  97
  98 $a6_0 = qr/^::(?:$c6:){0,6}$c6$/x;
  99
 100 # 2. 8 non-empty components
 101
 102 $a6_1 = qr/^(?:$c6:){7}$c6$/x;
 103
 104 # 3. This is the cunning one. Up to 7 components, one (and only one) of which
 105 # can be empty. We use 0 to cause a failure when we've already matched
 106 # an empty component and may be hitting other. This has to fail, because we
 107 # know we've just failed to match a component. We also do a final check to
 108 # ensure that there has been an empty component.
 109
 110 $a6_2 = qr/^(?: (?: $c6 | (?(1)0 | () ) ) : ){1,7}$c6 $ (?(1)|.)/x;
 111
 112 if ($host !~ /$a4 | $a6_0 | $a6_1 | $a6_2/x)
 113   {
 114   print "** Invalid IP address \"$host\"\n";
 115   print "Usage: exim_checkaccess <IP address> <email address> [exim options]\n";
 116   exit(1);
 117   }
 118
 119 # Build any remaining original arguments into a string for passing over
 120 # as Exim options.
 121
 122 $opt = "";
 123 for ($i = 3; $i < scalar(@ARGV); $i++) { $opt .= "$ARGV[$i] "; }
 124
 125 # If the string contains "-f xxxx", extract that as the sender. Otherwise
 126 # the sender is <>.
 127
 128 $sender    = "";
 129 if ($opt =~ /(?:^|\s)-f\s+(\S+|"[^"]*")/)
 130   {
 131   $sender = $1;
 132   $opt = $` . $';
 133   }
 134
 135 # Run a -bh test in Exim, passing the test data
 136
 137 $pid = open2(*IN, *OUT, "$exim_path -bh $host $opt 2>/dev/null");
 138 print OUT "HELO [$host]\r\n";
 139 print OUT "MAIL FROM:<$sender>\r\n";
 140 print OUT "RCPT TO:<$recipient>\r\n";
 141 print OUT "QUIT\r\n";
 142 close OUT;
 143
 144 # Read the output, ignoring anything but the SMTP response to the RCPT
 145 # command.
 146
 147 $count = 0;
 148 $reply = "";
 149
 150 while (<IN>)
 151   {
 152   next if !/^\d\d\d/;
 153   $reply .= $_;
 154   next if /^\d\d\d\-/;
 155
 156   if (++$count != 4)
 157     {
 158     $reply = "";
 159     next;
 160     }
 161
 162   # We have the response we want. Interpret it.
 163
 164   if ($reply =~ /^2\d\d/)
 165     {
 166     print "Accepted\n";
 167     }
 168   else
 169     {
 170     print "Rejected:\n";
 171     $reply =~ s/\n(.)/\n  $1/g;
 172     print "  $reply";
 173     }
 174   last;
 175   }
 176
 177 # Reap the child process
 178
 179 waitpid $pid, 0;
 180
 181 End