path: root/LedgerSMB/Session.pm

#=====================================================================
# LedgerSMB 
# Small Medium Business Accounting software
# http://www.ledgersmb.org/
# 
#
# Copyright (C) 2006
# This work contains copyrighted information from a number of sources all used
# with permission.  It is released under the GNU General Public License 
# Version 2 or, at your option, any later version.  See COPYRIGHT file for 
# details.
#
#
#======================================================================
#
# This file has undergone whitespace cleanup.
#
#======================================================================
# This package contains session related functions:
#
# check - checks validity of session based on the user's cookie and login
#
# create - creates a new session, writes cookie upon success
#
# destroy - destroys session
#====================================================================
package Session;

sub session_check {

    my ($cookie, $form, %myconfig) = @_;
    my ($sessionid, $token) = split /:/, $cookie;

    # connect to database
    my $dbh = DBI->connect($myconfig{dbconnect}, $myconfig{dbuser}, $myconfig{dbpasswd});

    my $checkQuery = $dbh->prepare("SELECT sl_login FROM session WHERE session_id = ? AND token = ? AND last_used > now() - ?::interval");

    my $updateAge = $dbh->prepare("UPDATE session SET last_used = now() WHERE session_id = ?;");

    #must be an integer
    $sessionid =~ s/[^0-9]//g;
    $sessionid = int $sessionid;

    #must be 32 chars long and contain hex chars
    $token =~ s/[^0-9a-f]//g;
    $token = substr($token, 0, 32);

    if (!$myconfig{timeout}){
        $timeout = "1 day";
    } else {
        $timeout = "$myconfig{timeout} seconds";
    }

    $checkQuery->execute($sessionid, $token, $timeout) || $form->dberror('Looking for session: ');
    my $sessionValid = $checkQuery->rows;

    if($sessionValid){

        #user has a valid session cookie, now check the user
        my ($sessionLogin) = $checkQuery->fetchrow_array;

        my $login = $form->{login};
        $login =~ s/[^a-zA-Z0-9@.-]//g;

        if($sessionLogin eq $login){
            $updateAge->execute($sessionid) || $form->dberror('Updating session age: ');
            return 1;

        } else {
            #something's wrong, they have the cookie, but wrong user. Hijack attempt?
            #delete the cookie in the browser
            print qq|Set-Cookie: LedgerSMB=; path=/;\n|;
            return 0;
        }
    
    } else {
        #cookie is not valid
        #delete the cookie in the browser
        print qq|Set-Cookie: LedgerSMB=; path=/;\n|;
        print qq|Set-Cookie: DiedHere=true; path=/;\n|;
        return 0;
    }
}

sub session_create {
    my ($form, %myconfig) = @_;

    # connect to database
    my $dbh = DBI->connect($myconfig{dbconnect}, $myconfig{dbuser}, $myconfig{dbpasswd});

    # TODO Change this to use %myconfig
    my $deleteExisting = $dbh->prepare("DELETE FROM session WHERE sl_login = ? AND age(last_used) > ?::interval");  

    my $seedRandom = $dbh->prepare("SELECT setseed(?);");

    my $fetchSequence = $dbh->prepare("SELECT nextval('session_session_id_seq'), md5(random());");
    
    my $createNew = $dbh->prepare("INSERT INTO session (session_id, sl_login, token) VALUES(?, ?, ?);");


    # this is assuming that $form->{login} is safe, which might be a bad assumption
    # so, I'm going to remove some chars, which might make previously valid logins invalid
    my $login = $form->{login};
    $login =~ s/[^a-zA-Z0-9@.-]//g;

    #delete any existing stale sessions with this login if they exist
    if (!$myconfig{timeout}){
       $myconfig{timeout} = 86400;
    }

    $deleteExisting->execute($login, "$myconfig{timeout} seconds") || $form->dberror('Delete from session: ');

    #doing the md5 and random stuff in the db so that LedgerSMB won't
    #require new perl modules (Digest::MD5 and a good random generator)
    $fetchSequence->execute() || $form->dberror('Fetch sequence id: ');
    my ($newSessionID, $newToken) = $fetchSequence->fetchrow_array;

    #create a new session
    $createNew->execute($newSessionID, $login, $newToken) || $form->dberror('Create new session: ');

    #reseed the random number generator
    my $randomSeed = 1.0 * ('0.'. (time() ^ ($$ + ($$ <<15))));
    $seedRandom->execute($randomSeed)|| $form->dberror('Reseed random generator: ');;

    $newCookieValue = $newSessionID . ':' . $newToken;

    #now set the cookie in the browser
    #TODO set domain from ENV, also set path to install path
    print qq|Set-Cookie: LedgerSMB=$newCookieValue; path=/;\n|;
    $form->{LedgerSMB} = $newCookieValue;
}

sub session_destroy {

    # Under the current architecture, this function is a bit problematic
    # %myconfig is often not defined when this function needs to be called.
    # which means that the db connection parameters are not available.
    # moving user prefs and the session table into a central db will solve this issue

    my ($form, %myconfig) = @_;

    my $login = $form->{login};
    $login =~ s/[^a-zA-Z0-9@.-]//g;

    # connect to database
    my $dbh = DBI->connect($myconfig{dbconnect}, $myconfig{dbuser}, $myconfig{dbpasswd});

    my $deleteExisting = $dbh->prepare("DELETE FROM session WHERE sl_login = ?;");
    $deleteExisting->execute($login) || $form->dberror('Delete from session: ');

    #delete the cookie in the browser
    print qq|Set-Cookie: LedgerSMB=; path=/;\n|;

}

1;