PHP/PAM to change user password?

wag2639 picture wag2639 · Jun 13, 2010 · Viewed 10.8k times · Source

Are there any working packages to change a linux user passwords using PHP?

I've tried using PECL:PAM but theres an error when it tries to change the password.

Edit:

PHP code:

echo pam_chpass($username, $password, $new_pass, &$error) ? 'good' : $error;

PHP (echo) output:

Permission denied (in pam_authenticate)

From /var/log/auth (these are actually from before, the log doesn't seem to be working ATM for some reason yet to be determined):

Jun 11 15:30:20 veda php: pam_unix(php:chauthtok): conversation failed
Jun 11 15:30:20 veda php: pam_unix(php:chauthtok): password - (old) token not obtained
Jun 11 15:30:20 veda php: pam_winbind(php:chauthtok): valid_user: wbcGetpwnam gave WBC_ERR_DOMAIN_NOT_FOUND

Other:

Sorry for the lack of details before, I was really tired when I posted the question but thats still a crappy excuse.

Answer

wag2639 picture wag2639 · Jun 18, 2010

After hours of research online, I wasn't able to find a super good option so I'm implemented this hack. It uses this article for changing passwords using PHP.

I'm also using the PECL:PAM package to add a little verification.

This page is on a secure HTTPS folder (automatic redirect via .htaccess)

<?php

$messages = array();

function change_password ($user, $currpwd, $newpwd) {

    // Open a handle to expect in write mode
    $p = popen('/usr/bin/expect','w');

    // Log conversation for verification
    $log = '/tmp/passwd_' . md5($user . time());
    $cmd .= "log_file -a \"$log\"; ";

    // Spawn a shell as $user
    $cmd .= "spawn /bin/su $user; ";
    $cmd .= "expect \"Password:\"; ";
    $cmd .= "send \"$currpwd\\r\"; ";
    $cmd .= "expect \"$user@\"; ";

    // Change the unix password
    $cmd .= "send \"/usr/bin/passwd\\r\"; ";
    $cmd .= "expect \"(current) UNIX password:\"; ";
    $cmd .= "send \"$currpwd\\r\"; ";
    $cmd .= "expect \"Enter new UNIX password:\"; ";
    $cmd .= "send \"$newpwd\\r\"; ";
    $cmd .= "expect \"Retype new UNIX password:\"; ";
    $cmd .= "send \"$newpwd\\r\"; ";
    $cmd .= "expect \"passwd: password updated successfully\"; ";

    // Commit the command to expect & close
    fwrite($p, $cmd); pclose ($p);

    // Read & delete the log
    $fp = fopen($log,r);
    $output = fread($fp, 2048);
    fclose($fp); unlink($log);
    $output = explode("\n",$output);

    return (trim($output[count($output)-2]) == 'passwd: password updated successfully') ? true : false;
}

function process_post() {

    if ((!isset($_SERVER['HTTP_REFERER'])) 
        || (strpos($_SERVER['HTTP_REFERER'], $_SERVER['SCRIPT_NAME']) === FALSE)) {

        echo "GO AWAY!";
        exit();
        return FALSE;

    }

    global $messages;

    $username           = trim($_POST['username']);
    $password_current   = trim($_POST['password_current']);
    $password_new       = trim($_POST['password_new']);
    $password_confirm   = trim($_POST['password_confirm']);

    // Check for blanks
    if ($username == '' || $password_current == '' || $password_new == '' || $password_confirm == '') {
        array_push(&$messages, "ERROR: You cannot leave any field empty.");
        return FALSE;
    }

    // Check username
    if (!ctype_alnum($username)) {
        array_push(&$messages, "ERROR: You've entered an invalid username.");
        return FALSE;
    }

    // Check to see if new password is correctly typed
    if ($password_new != $password_confirm) {       
        array_push(&$messages, "ERROR: New Password and Confirmation do not match.");
        return FALSE;
    }

    // Check if current password is valid (not really neccessary)
    if (!pam_auth($username, $password_current, &$error, FALSE)) {
        if (trim($error) == "Permission denied (in pam_authenticate)")
            array_push(&$messages, "ERROR: You've username/password was not accepted.");    
        else
            array_push(&$messages, "ERROR: " . $error);
        return FALSE;
    }

    if (change_password ($username, $password_current, $password_new))
        array_push(&$messages, "Password Successfully Changed");
    else 
        array_push(&$messages, "ERROR: Password change failed.");

}

if ($_SERVER['REQUEST_METHOD'] == 'POST') process_post();


?><html>
<head>


<title>Passwords</title>

<style type="text/css">

body {
    font-family: Verdana, Arial, sans-serif;
    font-size: 12px;
}

label {
    width: 150px;
    display: block;
    float: left;
}

input {
    float: left;
}

br {
    clear: both;
}

.message {
    font-size: 11px;
    font-weight: bold;
}

.error {
    color:#C00;
}


</style>

</head>


<body>

<h2>Change Passwords</h2>

<form action="<?= $_SERVER['SCRIPT_NAME'] ?>" method="post">

<fieldset>

<? if (count($messages) != 0) { 

    foreach ($messages as $message) { ?>

<p class="message<?= ((strpos($message, 'ERROR:') === FALSE) ? '' : ' error') ?>"><?= $message ?></p>

<? } } ?>

<label>Username: </label>
<input type="text" name="username" /><br />

<label>Current Password:</label>
<input type="password" name="password_current" /><br />

<label>New Password:</label>
<input type="password" name="password_new" /><br />

<label>Confirm Password:</label>
<input type="password" name="password_confirm" /><br />

<input type="reset" value="Reset" /> <input type="submit" value="Submit" />

</fieldset>


</form>


</body>
</html>

I also have this question/answer posted in https://serverfault.com/questions/150306/how-to-let-users-change-linux-password-from-web-browser/152409#152409