61de599c1b
find . -type f | xargs -n1 perl -pi.bak -0777 -e '$want = "#!perl -Tw"; s/\A#!.*\n/$want\n/; s/\A([^#])/$want\n\1/s'
151 lines
4.3 KiB
Perl
151 lines
4.3 KiB
Perl
#!perl -Tw
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=head1 NAME
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auth_checkpassword - Authenticate against a DJB style checkpassword program
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=head1 DESCRIPTION
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This plugin authenticates users against a DJB style checkpassword
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program. Unlike previous checkpassword implementations, this plugin
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expects qpsmtpd to be running as the qpsmtpd user. Privilege
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escalation can be attained by running the checkpassword binary setuid
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or with sudo.
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=head1 CONFIGURATION
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Configure the path to your checkpassword binary:
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echo "/usr/local/vpopmail/bin/vchkpw /usr/bin/true" > ~qpsmtpd/config/smtpauth-checkpassword
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vchkpw is the checkpassword program provided by vpopmail. Substitute
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your own checkpassword app as appropriate.
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If you are using vchkpw and this plugin is being executed by a user ID
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other than 89 or 0 (as is the default), and the vchkpw binary is not
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setuid (as is the default), this plugin will automatically prepend the
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vchkpw command with sudo. If that is the case, you must configure sudo
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by adding these two lines to your sudoers file:
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Defaults:qpsmtpd closefrom_override
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qpsmtpd ALL = (ALL) NOPASSWD: /usr/local/vpopmail/bin/vchkpw
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The closefrom_override option is necessary because, by default, sudo
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appropriates the first 3 file descriptors. Those descriptors are
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necessary to communicate with the checkpassword program. If you run
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qpsmtpd as some other user, adjust the sudo lines approriately.
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Using sudo is preferable to enabling setuid on the vchkpw binary. If
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you reinstall vpopmail and the setuid bit is lost, this plugin will be
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broken.
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=head1 SEE ALSO
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If you are using this plugin with vpopmail, please read the VPOPMAIL
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section in docs/authentication.pod
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=head1 DIAGNOSTICS
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Is the path in the config/smtpauth-checkpassword correct?
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Is the path to true in config/smtpauth-checkpassword correct?
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Is qpsmtpd running as the qpsmtpd user? If not, did you adjust the
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sudo configuration appropriately?
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If you are not using sudo, did you remember to make the vchkpw binary
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setuid (chmod 4711 ~vpopmail/bin/vchkpw)?
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While writing this plugin, I first wrote myself a little test script,
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which helped me identify the sudo closefrom_override issue. Here is
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that script:
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#!/usr/bin/perl
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use strict;
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my $sudo = "/usr/local/bin/sudo";
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$sudo .= " -C4 -u vpopmail";
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my $vchkpw = "/usr/local/vpopmail/bin/vchkpw";
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my $true = "/usr/bin/true";
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open(CPW,"|$sudo $vchkpw $true 3<&0");
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printf(CPW "%s\0%s\0Y123456\0",'user@example.com','pa55word');
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close(CPW);
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my $status = $?;
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print "FAIL\n" and exit if ( $status != 0 );
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print "OK\n";
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Save that script to vchkpw.pl and then run it as the same user that
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qpsmtpd runs as:
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setuidgid qpsmtpd perl vchkpw.pl
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If you aren't using sudo, then remove $sudo from the open line.
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=head1 ACKNOWLEDGEMENTS
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based upon authcheckpassword by Michael Holzt
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and adapted by Johan Almqvist 2006-01-18
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=head1 AUTHOR
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Matt Simerson <msimerson@cpan.org>
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=head1 COPYRIGHT AND LICENSE
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Copyright (c) 2010 Matt Simerson
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This plugin is licensed under the same terms as the qpsmtpd package itself.
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Please see the LICENSE file included with qpsmtpd for details.
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=cut
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sub register {
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my ($self, $qp) = @_;
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$self->register_hook("auth-plain", "auth_checkpassword");
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$self->register_hook("auth-login", "auth_checkpassword");
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}
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sub auth_checkpassword {
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my ($self, $transaction, $method, $user, $passClear, $passHash, $ticket) =
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@_;
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my $command = $self->qp->config("smtpauth-checkpassword")
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or return (DECLINED);
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my ($binary, $params) = $command =~ /^(\S+)(.*)$/;
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return (DECLINED) if (!-x $binary);
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my $sudo = get_sudo($binary);
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open(CPW, "|$sudo $binary $params 3<&0");
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printf(CPW "%s\0%s\0Y123456\0", $user, $passClear);
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close(CPW);
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my $status = $?;
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return (DECLINED) if ($status != 0);
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$self->connection->notes('authuser', $user);
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return (OK, "auth_checkpassword");
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}
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sub get_sudo {
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my $binary = shift;
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return '' if $> == 0; # running as root
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return '' if $> == 89 && $binary =~ /vchkpw/; # running as vpopmail
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my $mode = (stat($binary))[2];
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$mode = sprintf "%lo", $mode & 07777;
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return '' if $mode eq '4711'; # $binary is setuid
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my $sudo = `which sudo` || '/usr/local/bin/sudo';
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return '' if !-x $sudo;
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$sudo .= ' -C4'; # prevent sudo from clobber file descriptor 3
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return "$sudo -u vpopmail" if $binary =~ /vchkpw/;
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return $sudo;
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}
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