This file is indexed.

/usr/sbin/exim_checkaccess is in exim4-base 4.82-3ubuntu2.

This file is owned by root:root, with mode 0o755.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
#! /bin/sh

# Copyright (c) University of Cambridge, 1995 - 2007
# See the file NOTICE for conditions of use and distribution.

# Except when they appear in comments, the following placeholders in this
# source are replaced when it is turned into a runnable script:
#
# CONFIGURE_FILE_USE_NODE
# CONFIGURE_FILE
# BIN_DIRECTORY
# PERL_COMMAND

# This file has been so processed.

# A shell+perl wrapper script to run an automated -bh test to check out
# ACLs for incoming addresses.

# Save the shell arguments because we are going to need the shell variables
# while sorting out the configuration file.

args="$@"

# See if this installation is using the esoteric "USE_NODE" feature of Exim,
# in which it uses the host's name as a suffix for the configuration file name.

if [ "" = "yes" ]; then
  hostsuffix=.`uname -n`
fi

# Now find the configuration file name. This has got complicated because
# CONFIGURE_FILE may now be a list of files. The one that is used is the first
# one that exists. Mimic the code in readconf.c by testing first for the
# suffixed file in each case.

set `awk -F: '{ for (i = 1; i <= NF; i++) print $i }' <<End
/etc/exim4/exim4.conf:/var/lib/exim4/config.autogenerated
End
`
while [ "$config" = "" -a $# -gt 0 ] ; do
  if [ -f "$1$hostsuffix" ] ; then
    config="$1$hostsuffix"
  elif [ -f "$1" ] ; then
    config="$1"
  fi
  shift
done

# Search for an exim_path setting in the configure file; otherwise use the bin
# directory. BEWARE: a tab character is needed in the command below. It has had
# a nasty tendency to get lost in the past. Use a variable to hold a space and
# a tab to keep the tab in one place.

exim_path=`perl -ne 'chop;if (/^\s*exim_path\s*=\s*(.*)/){print "$1\n";last;}' $config`
if test "$exim_path" = ""; then exim_path=/usr/sbin/exim4; fi


#########################################################################


# Now run the perl script, passing in the Exim path and the arguments given
# to the overall script.

/usr/bin/perl - $exim_path $args <<'End'

use FileHandle;
use IPC::Open2;

if (scalar(@ARGV) < 3)
  {
  print "Usage: exim_checkaccess <IP address> <email address> [exim options]\n";
  exit(1);
  }

$exim_path = $ARGV[0];          # Set up by the calling shell script
$host      = $ARGV[1];          # Mandatory original first argument
$recipient = $ARGV[2];          # Mandatory original second argument

$c4 = qr/2 (?:[0-4]\d | 5[0-5]) | 1\d\d | \d{1,2}/x;  # IPv4 component
$a4 = qr/^$c4\.$c4\.$c4\.$c4$/;                       # IPv4 address

$c6 = qr/[0-9a-f]{1,4}/i;                             # IPv6 component

# Split the various formats of IPv6 addresses into several cases. I don't
# think I can graft regex that matches all of them without using alternatives.

# 1. Starts with :: followed by up to 7 components

$a6_0 = qr/^::(?:$c6:){0,6}$c6$/x;

# 2. 8 non-empty components

$a6_1 = qr/^(?:$c6:){7}$c6$/x;

# 3. This is the cunning one. Up to 7 components, one (and only one) of which
# can be empty. We use 0 to cause a failure when we've already matched
# an empty component and may be hitting other. This has to fail, because we
# know we've just failed to match a component. We also do a final check to
# ensure that there has been an empty component.

$a6_2 = qr/^(?: (?: $c6 | (?(1)0 | () ) ) : ){1,7}$c6 $ (?(1)|.)/x;

if ($host !~ /$a4 | $a6_0 | $a6_1 | $a6_2/x)
  {
  print "** Invalid IP address \"$host\"\n";
  print "Usage: exim_checkaccess <IP address> <email address> [exim options]\n";
  exit(1);
  }

# Build any remaining original arguments into a string for passing over
# as Exim options.

$opt = "";
for ($i = 3; $i < scalar(@ARGV); $i++) { $opt .= "$ARGV[$i] "; }

# If the string contains "-f xxxx", extract that as the sender. Otherwise
# the sender is <>.

$sender    = "";
if ($opt =~ /(?:^|\s)-f\s+(\S+|"[^"]*")/)
  {
  $sender = $1;
  $opt = $` . $';
  }

# Run a -bh test in Exim, passing the test data

$pid = open2(*IN, *OUT, "$exim_path -bh $host $opt 2>/dev/null");
print OUT "HELO [$host]\r\n";
print OUT "MAIL FROM:<$sender>\r\n";
print OUT "RCPT TO:<$recipient>\r\n";
print OUT "QUIT\r\n";
close OUT;

# Read the output, ignoring anything but the SMTP response to the RCPT
# command.

$count = 0;
$reply = "";

while (<IN>)
  {
  next if !/^\d\d\d/;
  $reply .= $_;
  next if /^\d\d\d\-/;

  if (++$count != 4)
    {
    $reply = "";
    next;
    }

  # We have the response we want. Interpret it.

  if ($reply =~ /^2\d\d/)
    {
    print "Accepted\n";
    }
  else
    {
    print "Rejected:\n";
    $reply =~ s/\n(.)/\n  $1/g;
    print "  $reply";
    }
  last;
  }

# Reap the child process

waitpid $pid, 0;

End