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
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
#!/usr/bin/perl -T
#----------------------------------------------------------------------
# socketmap lookup table returning the SASL login name(s) owning a given
# sender address
# Copyright © 2017,2020 Guilhem Moulin <guilhem@fripost.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#----------------------------------------------------------------------
use warnings;
use strict;
use Errno 'EINTR';
use Net::LDAPI ();
use Net::LDAP::Util qw/ldap_explode_dn escape_dn_value escape_filter_value/;
use Net::LDAP::Constant qw/LDAP_NO_SUCH_OBJECT/;
use Authen::SASL ();
# clean up PATH
$ENV{PATH} = join ':', qw{/usr/bin /bin};
delete @ENV{qw/IFS CDPATH ENV BASH_ENV/};
my $nProc = 2; # number of pre-forked servers
my $maxRequests = 32; # maximum number of requests per worker
my $POSTMASTER = 'postmaster@fripost.org'; # returned for forbidden envelope sender addresses
my $BASEDN = "ou=virtual,dc=fripost,dc=org";
my $BUFSIZE = 65536; # try to read that many bytes at the time
my $LDAPI = "ldapi://";
sub server();
# fdopen(3) the file descriptor FD
die "This service must be socket-activated.\n"
unless defined $ENV{LISTEN_PID} and $ENV{LISTEN_PID} == $$
and defined $ENV{LISTEN_FDS} and $ENV{LISTEN_FDS} == 1;
open my $S, '+<&=', 3 or die "fdopen: $!";
my @CHILDREN;
for (my $i = 0; $i < $nProc-1; $i++) {
my $pid = fork() // die "fork: $!";
if ($pid) {
push @CHILDREN, $pid;
} else {
server(); # child, never return
exit;
}
}
server();
waitpid $_ => 0 foreach @CHILDREN;
exit $?;
#############################################################################
sub server() {
for (my $n = 0; $n < $maxRequests; $n++) {
accept(my $conn, $S) or do {
next if $! == EINTR;
die "accept: $!";
};
my $reply = process_request($conn);
# encode the reply as a netstring and send it back
# https://cr.yp.to/proto/netstrings.txt
$reply = length($reply).':'.$reply.',';
my $len = length($reply);
for (my $i = 0; $i < $len;) {
my $n = syswrite($conn, $reply, $len-$i, $i) // do {
next if $! == EINTR;
warn "Can't write: $!";
last;
};
$i += $n;
}
close $conn or warn "Can't close: $!";
}
}
sub process_request($) {
my $conn = shift;
my ($buf, $offset) = (undef, 0);
# keep reading until the request length is determined
do {
my $n = sysread($conn, $buf, $BUFSIZE, $offset) // do {
next if $! == EINTR;
return "TEMP can't read: $!";
};
return "TEMP EOF" if $n == 0;
$offset += $n;
} until ($buf =~ /\A(0|[1-9][0-9]*):/);
# keep reading until the whole request is buffered
my $strlen = length("$1") + 1; # [len]":"
my $len = $strlen + $1 + 1; # [len]":"[string]","
while ($offset < $len) {
my $n = sysread($conn, $buf, $BUFSIZE, $offset) // do {
next if $! == EINTR;
return "TEMP can't read: $!";
};
return "TEMP EOF" if $n == 0;
$offset += $n;
}
# requests are of the form $name <space> $key, cf. socketmap_table(5)
my $i = index($buf, ' ', $strlen);
return "TEMP invalid input: $buf" unless $i > $strlen and substr($buf,-1) eq ',';
my $name = substr($buf, $strlen, $i-$strlen);
my $key = substr($buf, $i, -1);
return "TEMP invalid name: $name" unless $name eq 'sender_login';
$key =~ /\A(.+)@([^\@]+)\z/ or return "NOTFOUND "; # invalid sender address
my ($localpart, $domainpart) = ($1, $2);
$localpart =~ s/\+.*//; # strip extension, cf. postconf(5)'s $recipient_delimiter
my $ldap = Net::LDAPI::->new( $LDAPI ) //
return "TEMP couldn't create Net::LDAPI object";
$ldap->bind( undef, sasl => Authen::SASL::->new(mechanism => 'EXTERNAL') ) or
return "TEMP LDAP: couldn't bind";
my $reply = lookup_sender($ldap, $localpart, $domainpart);
$ldap->unbind();
return $reply;
}
sub lookup_sender($$$) {
my ($ldap, $l, $d) = @_;
my $filter = '(&(objectClass=FripostVirtualDomain)(fvd='.escape_filter_value($d).'))';
my $mesg = $ldap->search( base => $BASEDN, scope => 'one', deref => 'never'
, filter => $filter
, attrs => [qw/objectClass fripostOwner fripostPostmaster/]
);
return "TEMP LDAP error: ".$mesg->error() if $mesg->code;
my $entry = $mesg->pop_entry() // return "NOTFOUND "; # not a domain we know
return "TEMP LDAP error: multiple entry founds" if defined $mesg->pop_entry(); # sanity check
# domain postmasters are allowed to use any sender address
my @logins = $entry->get_value('fripostPostmaster', asref => 0);
my @owners = $entry->get_value('fripostOwner', asref => 0);
if (grep { $_ eq 'FripostVirtualAliasDomain' } $entry->get_value('objectClass', asref => 0)) {
# so are alias domain owners
push @logins, @owners;
} else {
my $dn = 'fvd='.escape_dn_value($d).','.$BASEDN;
my $filter = '(&(|(objectClass=FripostVirtualAlias)(objectClass=FripostVirtualList)(objectClass=FripostVirtualUser))(fvl='.escape_filter_value($l).'))';
my $mesg = $ldap->search( base => $dn, scope => 'one', deref => 'never'
, filter => $filter
, attrs => [qw/objectClass fripostOwner/]
);
unless ($mesg->code == 0 and defined ($entry = $mesg->pop_entry())) {
# domains owners are allowed to use any unkwown localpart as sender address
push @logins, @owners;
} else {
return "TEMP LDAP error: multiple entry founds" if defined $mesg->pop_entry(); # sanity check
if (grep { $_ eq 'FripostVirtualUser' } $entry->get_value('objectClass', asref => 0)) {
push @logins, $entry->dn();
} else {
# alias/list owners can use the address as sender, and so are the domains owners
push @logins, @owners, $entry->get_value('fripostOwner', asref => 0);
}
}
}
# convert DNs to SASL login names
my %logins;
foreach my $dn (@logins) {
next unless defined $dn;
$dn = ldap_explode_dn($dn, casefold => 'lower');
next unless defined $dn and $#$dn == 4;
my $l = $dn->[0]->{fvl} // next;
my $d = $dn->[1]->{fvd} // next;
$logins{$l.'@'.$d} = 1;
}
# if the entry is found in LDAP but doesn't have an owner, only
# $POSTMASTER is allowed to use it as sender address
my $reply = %logins ? join(',', keys %logins) : $POSTMASTER;
return "OK $reply";
}
|
