Auth changes (John Peacock with minor modifications by baud)
git-svn-id: https://svn.perl.org/qpsmtpd/trunk@252 958fd67b-6ff1-0310-b445-bb7760255be9
This commit is contained in:
Matt Sergeant
parent
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347
lib/Qpsmtpd/Auth.pm
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347
lib/Qpsmtpd/Auth.pm
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#!/usr/bin/perl -w
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=head1 NAME
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Qpsmtpd::Auth - Authentication framework for qpsmtpd
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=head1 DESCRIPTION
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Provides support for SMTP AUTH within qpsmtpd transactions, see
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L<http://www.faqs.org/rfcs/rfc2222.html>
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L<http://www.faqs.org/rfcs/rfc2554.html>
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for more details.
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=head1 USAGE
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This module is automatically loaded by Qpsmtpd::SMTP only if a plugin
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providing one of the defined L<Auth Hooks> is loaded. The only
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time this can happen is if the client process employs the EHLO command to
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initiate the SMTP session. If the client uses HELO, the AUTH command is
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not available and this module isn't even loaded.
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=head2 Plugin Design
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An authentication plugin can bind to one or more auth hooks or bind to all
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of them at once. See L<Multiple Hook Behavior> for more details.
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All plugins must provide two functions:
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=over 4
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=item * register()
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This is the standard function which is called by qpsmtpd for any plugin
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listed in config/plugins. Typically, an auth plugin should register at
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least one hook, like this:
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sub register {
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my ($self, $qp) = @_;
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$self->register_hook("auth", "authfunction");
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}
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where in this case "auth" means this plugin expects to support any of
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the defined authentication methods.
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=item * authfunction()
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The plugin must provide an authentication function which is part of
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the register_hook call. That function will receive the following
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six parameters when called:
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=over 4
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=item $self
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A Qpsmtpd::Plugin object, which can be used, for example, to emit log
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entries or to send responses to the remote SMTP client.
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=item $transaction
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A Qpsmtpd::Transaction object which can be used to examine information
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about the current SMTP session like the remote IP address.
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=item $user
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Whatever the remote SMTP client sent to identify the user (may be bare
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name or fully qualified e-mail address).
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=item $clearPassword
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If the particular authentication method supports unencrypted passwords
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(currently PLAIN and LOGIN), which will be the plaintext password sent
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by the remote SMTP client.
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=item $hashPassword
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An encrypted form of the remote user's password, using the MD-5 algorithm
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(see also the $ticket parameter).
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=item $ticket
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This is the cryptographic challenge which was sent to the client as part
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of a CRAM-MD5 transaction. Since the MD-5 algorithm is one-way, the same
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$ticket value must be used on the backend to compare with the encrypted
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password sent in $hashPassword.
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=back
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=back
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Plugins should perform whatever checking they want and then return one
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of the following values (taken from Qpsmtpd::Constants):
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=over 4
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=item OK
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If the authentication has succeeded, the plugin can return this value and
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all subsequently registered hooks will be skipped.
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=item DECLINE
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If the authentication has failed, but any additional plugins should be run,
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this value will be returned. If none of the registered plugins succeed, the
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overall authentication will fail.
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=item DENY
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If the authentication has failed, and the plugin wishes this to short circuit
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any further testing, it should return this value. For example, a plugin could
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register the L<auth-plain> hook and immediately fail any connection which is
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not trusted (i.e. not in the same network).
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Another reason to return DENY over DECLINE would be if the user name matched
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an existing account but the password failed to match. This would make a
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dictionary-based attack much harder to accomplish. See the example authsql
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plugin for how this might be accomplished
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By returning DENY, no further authentication attempts will be made using the
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current method and data. A remote SMTP client is free to attempt a second
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auth method if the first one fails.
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=back
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Plugins may also return an optional message with the return code, e.g.
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return (DENY, "If you forgot your password, contact your admin");
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and this will be appended to whatever response is sent to the remote SMTP
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client. There is no guarantee that the end user will see this information,
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though, since some prominent MTA's (produced by M$oft) I<helpfully>
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hide this information under the default configuration. This message will
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be logged locally, if appropriate based on the configured log level. If
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you are running multiple auth plugins, it is helpful to include at least
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the plugin name in the returned message (for debugging purposes).
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=head1 Auth Hooks
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The currently defined authentication methods are:
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=over 4
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=item * auth-plain
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Any plugin which registers an auth-plain hook will engage in a plaintext
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prompted negotiation. This is the least secure authentication method since
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both the user name and password are visible in plaintext. Most SMTP clients
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will preferentially chose a more secure method if it is advertised by the
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server.
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=item * auth-login
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A slightly more secure method where the username and password are Base-64
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encoded before sending. This is still an insecure method, since it is
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trivial to decode the Base-64 data. Again, it will not normally be chosen
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by SMTP clients unless a more secure method is not available (or if it fails).
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CURRENTLY NOT SUPPORTED DUE TO LACK OF DOCUMENTATION ON FUNCTIONALITY
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=item * auth-cram-md5
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A cryptographically secure authentication method which employs a one-way
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hashing function to transmit the secret information without significant
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risk between the client and server. The server provides a challenge key
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L<$ticket>, which the client uses to encrypt the user's password.
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Then both user name and password are concatenated and Base-64 encoded before
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transmission.
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This hook must normally have access to the user's plaintext password,
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since there is no way to extract that information from the transmitted data.
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Since the CRAM-MD5 scheme requires that the server send the challenge
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L<$ticket> before knowing what user is attempting to log in, there is no way
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to use any existing MD5-encrypted password (like is frequently used with MySQL).
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=item * auth
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A catch-all hook which requires that the plugin support all three preceeding
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authentication methods. Any plugins registering the auth hook will be run
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only after all other plugins registered for the specific authentication
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method which was requested. This allows you to move from more specific
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plugins to more general plugins (e.g. local accounts first vs replicated
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accounts with expensive network access later).
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=back
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=head2 Multiple Hook Behavior
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If more than one hook is registered for a given authentication method, then
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they will be tried in the order that they appear in the config/plugins file
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unless one of the plugins returns DENY, which will immediately cease all
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authentication attempts for this transaction.
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In addition, all plugins that are registered for a specific auth hook will
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be tried before any plugins which are registered for the general auth hook.
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=head1 AUTHOR
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John Peacock <jpeacock@cpan.org>
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=head1 COPYRIGHT AND LICENSE
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Copyright (c) 2004 John Peacock
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Portions based on original code by Ask Bjoern Hansen and Guillaume Filion
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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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package Qpsmtpd::Auth;
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use Qpsmtpd::Constants;
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use MIME::Base64;
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sub Qpsmtpd::SMTP::auth {
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my ( $self, $arg, @stuff ) = @_;
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#they AUTH'd once already
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return $self->respond( 503, "but you already said AUTH ..." )
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if ( defined $self->{_auth}
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and $self->{_auth} == OK );
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return $self->{_auth} = Qpsmtpd::Auth::SASL( $self, $arg, @stuff );
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}
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sub SASL {
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# $DB::single = 1;
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my ( $session, $mechanism, $prekey ) = @_;
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my ( $user, $passClear, $passHash, $ticket );
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$mechanism = lc($mechanism);
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if ( $mechanism eq "plain" ) {
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if ($prekey) {
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( $passHash, $user, $passClear ) = split /\x0/,
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decode_base64($prekey);
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}
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else {
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$session->respond( 334, "Username:" );
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# We read the username and password from STDIN
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$user = <>;
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chop($user);
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chop($user);
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if ( $user eq '*' ) {
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$session->respond( 501, "Authentification canceled" );
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return DECLINED;
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}
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$session->respond( 334, "Password:" );
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$passClear = <>;
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chop($passClear);
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chop($passClear);
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if ( $passClear eq '*' ) {
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$session->respond( 501, "Authentification canceled" );
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return DECLINED;
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}
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}
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}
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# elsif ($mechanism eq "login") {
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# if ( $prekey ) {
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# ($passHash, $user, $passClear) = split /\x0/, decode_base64($prekey);
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# }
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# else {
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#
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# $session->respond(334, encode_base64("User Name:"));
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# $user = decode_base64(<>);
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# #warn("Debug: User: '$user'");
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# if ($user eq '*') {
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# $session->respond(501, "Authentification canceled");
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# return DECLINED;
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# }
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#
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# $session->respond(334, encode_base64("Password:"));
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# $passClear = <>;
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# $passClear = decode_base64($passClear);
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# #warn("Debug: Pass: '$pass'");
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# if ($passClear eq '*') {
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# $session->respond(501, "Authentification canceled");
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# return DECLINED;
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# }
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# }
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# }
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elsif ( $mechanism eq "cram-md5" ) {
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# rand() is not cryptographic, but we only need to generate a globally
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# unique number. The rand() is there in case the user logs in more than
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# once in the same second, of if the clock is skewed.
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$ticket = sprintf( "<%x.%x\@" . $session->config("me") . ">",
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rand(1000000), time() );
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# We send the ticket encoded in Base64
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$session->respond( 334, encode_base64( $ticket, "" ) );
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my $line = <>;
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chop($line);
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chop($line);
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if ( $line eq '*' ) {
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$session->respond( 501, "Authentification canceled" );
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return DECLINED;
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}
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( $user, $passHash ) = split( ' ', decode_base64($line) );
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}
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else {
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$session->respond( 500, "Unrecognized authentification mechanism" );
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return DECLINED;
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}
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# try running the specific hooks first
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my ( $rc, $msg ) =
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$session->run_hooks( "auth-$mechanism", $mechanism, $user, $passClear,
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$passHash, $ticket );
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# try running the polymorphous hooks next
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if ( $rc == DECLINED ) {
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( $rc, $msg ) =
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$session->run_hooks( "auth", $mechanism, $user, $passClear, $passHash,
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$ticket );
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}
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if ( $rc == OK ) {
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$msg = "Authentication successful" .
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( defined $msg ? " - " . $msg : "" );
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$session->respond( 235, $msg );
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$ENV{RELAYCLIENT} = 1;
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$session->log( LOGINFO, $msg );
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return OK;
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}
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else {
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$msg = "Authentication failed" .
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( defined $msg ? " - " . $msg : "" );
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$session->respond( 535, $msg );
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$session->log( LOGERROR, $msg );
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return DENY;
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}
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}
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# tag: qpsmtpd plugin that sets RELAYCLIENT when the user authentifies
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1;
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@ -3,6 +3,7 @@ use strict;
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my %hooks = map { $_ => 1 } qw(
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config queue data_post quit rcpt mail ehlo helo
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auth auth-plain auth-login auth-cram-md5
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connect reset_transaction unrecognized_command disconnect
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);
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@ -10,6 +10,7 @@ use Qpsmtpd::Connection;
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use Qpsmtpd::Transaction;
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use Qpsmtpd::Plugin;
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use Qpsmtpd::Constants;
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use Qpsmtpd::Auth;
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use Mail::Address ();
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use Mail::Header ();
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@ -166,6 +167,25 @@ sub ehlo {
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? @{ $self->transaction->notes('capabilities') }
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: ();
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# Check for possible AUTH mechanisms
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my %auth_mechanisms;
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HOOK: foreach my $hook ( keys %{$self->{_hooks}} ) {
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if ( $hook =~ m/^auth-?(.+)?$/ ) {
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if ( defined $1 ) {
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$auth_mechanisms{uc($1)} = 1;
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}
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else { # at least one polymorphous auth provider
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%auth_mechanisms = map {$_,1} qw(PLAIN CRAM-MD5);
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last HOOK;
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}
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}
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}
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if ( %auth_mechanisms ) {
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push @capabilities, 'AUTH '.join(" ",keys(%auth_mechanisms));
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$self->{_commands}->{'auth'} = "";
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}
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$self->respond(250,
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$self->config("me") . " Hi " . $conn->remote_info . " [" . $conn->remote_ip ."]",
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"PIPELINING",
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@ -415,6 +435,10 @@ sub data {
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my $smtp = $self->connection->hello eq "ehlo" ? "ESMTP" : "SMTP";
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# only true if client authenticated
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if ( defined $self->{_auth} and $self->{_auth} == OK ) {
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$header->add("X-Qpsmtpd-Auth","True");
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}
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$header->add("Received", "from ".$self->connection->remote_info
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." (HELO ".$self->connection->hello_host . ") (".$self->connection->remote_ip
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23
plugins/authdeny
Normal file
23
plugins/authdeny
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@ -0,0 +1,23 @@
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#!/usr/bin/perl
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#
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# This plugin doesn't actually check anything and will fail any
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# user no matter what they type. It is strictly a proof of concept for
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# the Qpsmtpd::Auth module. Don't run this in production!!!
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#
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sub register {
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my ( $self, $qp ) = @_;
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$self->register_hook( "auth", "authdeny" );
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}
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sub authdeny {
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my ( $self, $transaction, $method, $user, $passClear, $passHash, $ticket ) =
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@_;
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# $DB::single = 1;
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$self->log( LOGWARN, "Cannot authenticate using authdeny" );
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return ( DECLINED, "$user is not free to abuse my relay" );
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}
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27
plugins/authnull
Normal file
27
plugins/authnull
Normal file
@ -0,0 +1,27 @@
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#!/usr/bin/perl
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#
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# This plugin doesn't actually check anything and will authenticate any
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# user no matter what they type. It is strictly a proof of concept for
|
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# the Qpsmtpd::Auth module. Don't run this in production!!!
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#
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sub register {
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my ( $self, $qp ) = @_;
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# $self->register_hook("auth-plain", "authnull");
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# $self->register_hook("auth-login", "authnull");
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# $self->register_hook("auth-cram-md5", "authnull");
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$self->register_hook( "auth", "authnull" );
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}
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sub authnull {
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my ( $self, $transaction, $method, $user, $passClear, $passHash, $ticket ) =
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@_;
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# $DB::single = 1;
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$self->log( LOGERROR, "authenticating $user using $method" );
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return ( OK, "$user is free to abuse my relay" );
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}
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116
plugins/authsql
Normal file
116
plugins/authsql
Normal file
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#!/usr/bin/perl -w
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=head1 NAME
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||||
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||||
authsql - Authenticate to vpopmail via MySQL
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=head1 DESCRIPTION
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|
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This plugin authenticates vpopmail users directly against a standard
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vpopmail MySQL database. It makes the not-unreasonable assumption that
|
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both pw_name and pw_domain are lowercase only (qmail doesn't actually care).
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It also requires that vpopmail be built with the recommended
|
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'--enable-clear-passwd=y' option, because there is no other way to compare
|
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the password with CRAM-MD5.
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=head1 CONFIGURATION
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Decide which authentication methods you are willing to support and uncomment
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the lines in the register() sub. See the POD for Qspmtpd::Auth for more
|
||||
details on the ramifications of supporting various authentication methods.
|
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Then, change the database information at the top of the authsql() sub so that
|
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the module can access the database. This can be a read-only account since
|
||||
the plugin does not update the last accessed time (yet, see below).
|
||||
|
||||
The remote user must login with a fully qualified e-mail address (i.e. both
|
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account name and domain), even if they don't normally need to. This is
|
||||
because the vpopmail table has a unique index on pw_name/pw_domain, and this
|
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module requires that only a single record be returned from the database.
|
||||
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=head1 FUTURE DIRECTION
|
||||
|
||||
The default MySQL configuration for vpopmail includes a table to log access,
|
||||
lastauth, which could conceivably be updated upon sucessful authentication.
|
||||
The addition of this feature is left as an exercise for someone who cares. ;)
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||||
|
||||
=head1 AUTHOR
|
||||
|
||||
John Peacock <jpeacock@cpan.org>
|
||||
|
||||
=head1 COPYRIGHT AND LICENSE
|
||||
|
||||
Copyright (c) 2004 John Peacock
|
||||
|
||||
This plugin is licensed under the same terms as the qpsmtpd package itself.
|
||||
Please see the LICENSE file included with qpsmtpd for details.
|
||||
|
||||
|
||||
=cut
|
||||
|
||||
sub register {
|
||||
my ( $self, $qp ) = @_;
|
||||
|
||||
$self->register_hook( "auth-plain", "authsql" );
|
||||
|
||||
# $self->register_hook("auth-cram-md5", "authsql");
|
||||
|
||||
}
|
||||
|
||||
sub authsql {
|
||||
use DBI;
|
||||
use Qpsmtpd::Constants;
|
||||
use Digest::HMAC_MD5 qw(hmac_md5_hex);
|
||||
|
||||
# $DB::single = 1;
|
||||
|
||||
my $connect = "dbi:mysql:dbname=vpopmail";
|
||||
my $dbuser = "vpopmailuser";
|
||||
my $dbpasswd = "**********";
|
||||
|
||||
my $dbh = DBI->connect( $connect, $dbuser, $dbpasswd );
|
||||
$dbh->{ShowErrorStatement} = 1;
|
||||
|
||||
my ( $self, $transaction, $method, $user, $passClear, $passHash, $ticket ) =
|
||||
@_;
|
||||
my ( $pw_name, $pw_domain ) = split "@", lc($user);
|
||||
|
||||
unless ( defined $pw_domain ) {
|
||||
return DECLINED;
|
||||
}
|
||||
|
||||
my $sth = $dbh->prepare(<<SQL);
|
||||
select pw_clear_passwd
|
||||
from vpopmail
|
||||
where pw_name = ? and pw_domain = ?
|
||||
SQL
|
||||
|
||||
$sth->execute( $pw_name, $pw_domain );
|
||||
|
||||
my ($pw_clear_passwd) = $sth->fetchrow_array;
|
||||
|
||||
$sth->finish;
|
||||
$dbh->disconnect;
|
||||
|
||||
unless ( defined $pw_clear_passwd ) {
|
||||
|
||||
# if this isn't defined then the user doesn't exist here
|
||||
# or the administrator forgot to build with --enable-clear-passwd=y
|
||||
return ( DECLINED, "authsql/$method" );
|
||||
}
|
||||
|
||||
# at this point we can assume the user name matched
|
||||
if (
|
||||
( defined $passClear
|
||||
and $pw_clear_passwd eq $passClear ) or
|
||||
( defined $passHash
|
||||
and $passHash eq hmac_md5_hex( $ticket, $pw_clear_passwd ) )
|
||||
)
|
||||
{
|
||||
|
||||
return ( OK, "authsql/$method" );
|
||||
}
|
||||
else {
|
||||
return ( DENY, "authsql/$method - wrong password" );
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user