package Apache::Authn::Redmine;

=head1 Apache::Authn::Redmine

Redmine - a mod_perl module to authenticate webdav subversion users
against redmine database

=head1 SYNOPSIS

This module allow anonymous users to browse public project and
registred users to browse and commit their project. Authentication is
done against the redmine database or the LDAP configured in redmine.

This method is far simpler than the one with pam_* and works with all
database without an hassle but you need to have apache/mod_perl on the
svn server.

=head1 INSTALLATION

For this to automagically work, you need to have a recent reposman.rb
(after r860) and if you already use reposman, read the last section to
migrate.

Sorry ruby users but you need some perl modules, at least mod_perl2,
DBI and DBD::mysql (or the DBD driver for you database as it should
work on allmost all databases).

On debian/ubuntu you must do :

  aptitude install libapache-dbi-perl libapache2-mod-perl2 libdbd-mysql-perl

If your Redmine users use LDAP authentication, you will also need
Authen::Simple::LDAP (and IO::Socket::SSL if LDAPS is used):

  aptitude install libauthen-simple-ldap-perl libio-socket-ssl-perl

=head1 CONFIGURATION

   ## This module has to be in your perl path
   ## eg:  /usr/lib/perl5/Apache/Authn/Redmine.pm
   PerlLoadModule Apache::Authn::Redmine
   <Location /svn>
     DAV svn
     SVNParentPath "/var/svn"

     AuthType Basic
     AuthName redmine
     Require valid-user

     PerlAccessHandler Apache::Authn::Redmine::access_handler
     PerlAuthenHandler Apache::Authn::Redmine::authen_handler
  
     ## for mysql
     RedmineDSN "DBI:mysql:database=databasename;host=my.db.server"
     ## for postgres
     # RedmineDSN "DBI:Pg:dbname=databasename;host=my.db.server"

     RedmineDbUser "redmine"
     RedmineDbPass "password"
     ## Optional where clause (fulltext search would be slow and
     ## database dependant).
     # RedmineDbWhereClause "and members.role_id IN (1,2)"
     ## Optional credentials cache size
     # RedmineCacheCredsMax 50
  </Location>

To be able to browse repository inside redmine, you must add something
like that :

   <Location /svn-private>
     DAV svn
     SVNParentPath "/var/svn"
     Order deny,allow
     Deny from all
     # only allow reading orders
     <Limit GET PROPFIND OPTIONS REPORT>
       Allow from redmine.server.ip
     </Limit>
   </Location>

and you will have to use this reposman.rb command line to create repository :

  reposman.rb --redmine my.redmine.server --svn-dir /var/svn --owner www-data -u http://svn.server/svn-private/

=head1 MIGRATION FROM OLDER RELEASES

If you use an older reposman.rb (r860 or before), you need to change
rights on repositories to allow the apache user to read and write
S<them :>

  sudo chown -R www-data /var/svn/*
  sudo chmod -R u+w /var/svn/*

And you need to upgrade at least reposman.rb (after r860).

=cut

use strict;
use warnings FATAL => 'all', NONFATAL => 'redefine';

use DBI;
use Digest::SHA1;
# optional module for LDAP authentication
my $CanUseLDAPAuth = eval("use Authen::Simple::LDAP; 1");

use Apache2::Module;
use Apache2::Access;
use Apache2::ServerRec qw();
use Apache2::RequestRec qw();
use Apache2::RequestUtil qw();
use Apache2::Const qw(:common :override :cmd_how);
use APR::Pool ();
use APR::Table ();

# use Apache2::Directive qw();

my @directives = (
  {
    name => 'RedmineDSN',
    req_override => OR_AUTHCFG,
    args_how => TAKE1,
    errmsg => 'Dsn in format used by Perl DBI. eg: "DBI:Pg:dbname=databasename;host=my.db.server"',
  },
  {
    name => 'RedmineDbUser',
    req_override => OR_AUTHCFG,
    args_how => TAKE1,
  },
  {
    name => 'RedmineDbPass',
    req_override => OR_AUTHCFG,
    args_how => TAKE1,
  },
  {
    name => 'RedmineDbWhereClause',
    req_override => OR_AUTHCFG,
    args_how => TAKE1,
  },
  {
    name => 'RedmineCacheCredsMax',
    req_override => OR_AUTHCFG,
    args_how => TAKE1,
    errmsg => 'RedmineCacheCredsMax must be decimal number',
  },
);

sub RedmineDSN { 
  my ($self, $parms, $arg) = @_;
  $self->{RedmineDSN} = $arg;
  my $query = "SELECT 
                 hashed_password, salt, auth_source_id, permissions
              FROM members, projects, users, roles, member_roles
              WHERE 
                projects.id=members.project_id
                AND member_roles.member_id=members.id
                AND users.id=members.user_id 
                AND roles.id=member_roles.role_id
                AND users.status=1 
                AND login=? 
                AND identifier=? ";
  $self->{RedmineQuery} = trim($query);
}

sub RedmineDbUser { set_val('RedmineDbUser', @_); }
sub RedmineDbPass { set_val('RedmineDbPass', @_); }
sub RedmineDbWhereClause { 
  my ($self, $parms, $arg) = @_;
  $self->{RedmineQuery} = trim($self->{RedmineQuery}.($arg ? $arg : "")." ");
}

sub RedmineCacheCredsMax { 
  my ($self, $parms, $arg) = @_;
  if ($arg) {
    $self->{RedmineCachePool} = APR::Pool->new;
    $self->{RedmineCacheCreds} = APR::Table::make($self->{RedmineCachePool}, $arg);
    $self->{RedmineCacheCredsCount} = 0;
    $self->{RedmineCacheCredsMax} = $arg;
  }
}

sub trim {
  my $string = shift;
  $string =~ s/\s{2,}/ /g;
  return $string;
}

sub set_val {
  my ($key, $self, $parms, $arg) = @_;
  $self->{$key} = $arg;
}

Apache2::Module::add(__PACKAGE__, \@directives);


my %read_only_methods = map { $_ => 1 } qw/GET PROPFIND REPORT OPTIONS/;

sub access_handler {
  my $r = shift;

  unless ($r->some_auth_required) {
      $r->log_reason("No authentication has been configured");
      return FORBIDDEN;
  }

  my $method = $r->method;
  return OK unless defined $read_only_methods{$method};

  my $project_id = get_project_identifier($r);

  $r->set_handlers(PerlAuthenHandler => [\&OK])
      if is_public_project($project_id, $r) && anonymous_role_allows_browse_repository($r);

  return OK
}

sub authen_handler {
  my $r = shift;
  
  my ($res, $redmine_pass) =  $r->get_basic_auth_pw();
  return $res unless $res == OK;
  
  if (is_member($r->user, $redmine_pass, $r)) {
      return OK;
  } else {
      $r->note_auth_failure();
      return AUTH_REQUIRED;
  }
}

# check if authentication is forced
sub is_authentication_forced {
  my $r = shift;

  my $dbh = connect_database($r);
  my $sth = $dbh->prepare(
    "SELECT value FROM settings where settings.name = 'login_required';"
  );

  $sth->execute();
  my $ret = 0;
  if (my @row = $sth->fetchrow_array) {
    if ($row[0] eq "1" || $row[0] eq "t") {
      $ret = 1;
    }
  }
  $sth->finish();
  undef $sth;
  
  $dbh->disconnect();
  undef $dbh;

  $ret;
}

sub is_public_project {
    my $project_id = shift;
    my $r = shift;
    
    if (is_authentication_forced($r)) {
      return 0;
    }

    my $dbh = connect_database($r);
    my $sth = $dbh->prepare(
        "SELECT is_public FROM projects WHERE projects.identifier = ?;"
    );

    $sth->execute($project_id);
    my $ret = 0;
    if (my @row = $sth->fetchrow_array) {
    	if ($row[0] eq "1" || $row[0] eq "t") {
    		$ret = 1;
    	}
    }
    $sth->finish();
    undef $sth;
    $dbh->disconnect();
    undef $dbh;

    $ret;
}

sub anonymous_role_allows_browse_repository {
  my $r = shift;
  
  my $dbh = connect_database($r);
  my $sth = $dbh->prepare(
      "SELECT permissions FROM roles WHERE builtin = 2;"
  );
  
  $sth->execute();
  my $ret = 0;
  if (my @row = $sth->fetchrow_array) {
    if ($row[0] =~ /:browse_repository/) {
      $ret = 1;
    }
  }
  $sth->finish();
  undef $sth;
  $dbh->disconnect();
  undef $dbh;
  
  $ret;
}

# perhaps we should use repository right (other read right) to check public access.
# it could be faster BUT it doesn't work for the moment.
# sub is_public_project_by_file {
#     my $project_id = shift;
#     my $r = shift;

#     my $tree = Apache2::Directive::conftree();
#     my $node = $tree->lookup('Location', $r->location);
#     my $hash = $node->as_hash;

#     my $svnparentpath = $hash->{SVNParentPath};
#     my $repos_path = $svnparentpath . "/" . $project_id;
#     return 1 if (stat($repos_path))[2] & 00007;
# }

sub is_member {
  my $redmine_user = shift;
  my $redmine_pass = shift;
  my $r = shift;

  my $dbh         = connect_database($r);
  my $project_id  = get_project_identifier($r);

  my $pass_digest = Digest::SHA1::sha1_hex($redmine_pass);
  
  my $access_mode = defined $read_only_methods{$r->method} ? "R" : "W";

  my $cfg = Apache2::Module::get_config(__PACKAGE__, $r->server, $r->per_dir_config);
  my $usrprojpass;
  if ($cfg->{RedmineCacheCredsMax}) {
    $usrprojpass = $cfg->{RedmineCacheCreds}->get($redmine_user.":".$project_id.":".$access_mode);
    return 1 if (defined $usrprojpass and ($usrprojpass eq $pass_digest));
  }
  my $query = $cfg->{RedmineQuery};
  my $sth = $dbh->prepare($query);
  $sth->execute($redmine_user, $project_id);

  my $ret;
  while (my ($hashed_password, $salt, $auth_source_id, $permissions) = $sth->fetchrow_array) {

      unless ($auth_source_id) {
	  			my $method = $r->method;
          my $salted_password = Digest::SHA1::sha1_hex($salt.$pass_digest);
					if ($hashed_password eq $salted_password && (($access_mode eq "R" && $permissions =~ /:browse_repository/) || $permissions =~ /:commit_access/) ) {
              $ret = 1;
              last;
          }
      } elsif ($CanUseLDAPAuth) {
          my $sthldap = $dbh->prepare(
              "SELECT host,port,tls,account,account_password,base_dn,attr_login from auth_sources WHERE id = ?;"
          );
          $sthldap->execute($auth_source_id);
          while (my @rowldap = $sthldap->fetchrow_array) {
            my $ldap = Authen::Simple::LDAP->new(
                host    =>      ($rowldap[2] eq "1" || $rowldap[2] eq "t") ? "ldaps://$rowldap[0]:$rowldap[1]" : $rowldap[0],
                port    =>      $rowldap[1],
                basedn  =>      $rowldap[5],
                binddn  =>      $rowldap[3] ? $rowldap[3] : "",
                bindpw  =>      $rowldap[4] ? $rowldap[4] : "",
                filter  =>      "(".$rowldap[6]."=%s)"
            );
            my $method = $r->method;
            $ret = 1 if ($ldap->authenticate($redmine_user, $redmine_pass) && (($access_mode eq "R" && $permissions =~ /:browse_repository/) || $permissions =~ /:commit_access/));

          }
          $sthldap->finish();
          undef $sthldap;
      }
  }
  $sth->finish();
  undef $sth;
  $dbh->disconnect();
  undef $dbh;

  if ($cfg->{RedmineCacheCredsMax} and $ret) {
    if (defined $usrprojpass) {
      $cfg->{RedmineCacheCreds}->set($redmine_user.":".$project_id.":".$access_mode, $pass_digest);
    } else {
      if ($cfg->{RedmineCacheCredsCount} < $cfg->{RedmineCacheCredsMax}) {
        $cfg->{RedmineCacheCreds}->set($redmine_user.":".$project_id.":".$access_mode, $pass_digest);
        $cfg->{RedmineCacheCredsCount}++;
      } else {
        $cfg->{RedmineCacheCreds}->clear();
        $cfg->{RedmineCacheCredsCount} = 0;
      }
    }
  }

  $ret;
}

sub get_project_identifier {
    my $r = shift;
    
    my $location = $r->location;
    my ($identifier) = $r->uri =~ m{$location/*([^/]+)};
    $identifier;
}

sub connect_database {
    my $r = shift;
    
    my $cfg = Apache2::Module::get_config(__PACKAGE__, $r->server, $r->per_dir_config);
    return DBI->connect($cfg->{RedmineDSN}, $cfg->{RedmineDbUser}, $cfg->{RedmineDbPass});
}

1;