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用 PHP 进行 HTTP 认证
PHP 的 HTTP 认证机制仅在 PHP 以 Apache 模块方式运行时才有效，因此该功能不适用于 CGI 版本。在 Apache 模块的 PHP 脚本中，可以用 header() 函数来向客户端浏览器发送“Authentication Required”信息，使其弹出一个用户名／密码输入窗口。当用户输入用户名和密码后，包含有 URL 的 PHP 脚本将会加上预定义变量 PHP_AUTH_USER ， PHP_AUTH_PW 和 AUTH_TYPE 被再次调用，这三个变量分别被设定为用户名，密码和认证类型。预定义变量保存在 $_SERVER 或者 $HTTP_SERVER_VARS 数组中。支持“Basic”和“Digest”（自 PHP 5.1.0 起）认证方法。请参阅 header() 函数以获取更多信息。
Note: PHP 版本问题
Autoglobals 全局变量，包括 $_SERVER等，自 PHP » 4.1.0 起有效， $HTTP_SERVER_VARS 从 PHP 3 开始有效。
以下是在页面上强迫客户端认证的脚本范例：
Example #1 Basic HTTP 认证范例
<?php
if (!isset( $_SERVER [ 'PHP_AUTH_USER' ])) {
header ( 'WWW-Authenticate: Basic realm="My Realm"' );
header ( 'HTTP/1.0 401 Unauthorized' );
echo 'Text to send if user hits Cancel button' ;
exit;
} else {
echo "<p>Hello { $_SERVER [ 'PHP_AUTH_USER' ]} .</p>" ;
echo "<p>You entered { $_SERVER [ 'PHP_AUTH_PW' ]} as your password.</p>" ;
}
?>
Example #2 Digest HTTP 认证范例
本例演示怎样实现一个简单的 Digest HTTP 认证脚本。更多信息请参考 » RFC 2617。
<?php
$realm = 'Restricted area' ;
//user => password
$users = array( 'admin' => 'mypass' , 'guest' => 'guest' );
if (empty( $_SERVER [ 'PHP_AUTH_DIGEST' ])) {
header ( 'HTTP/1.1 401 Unauthorized' );
header ( 'WWW-Authenticate: Digest realm="' . $realm .
'" qop="auth" nonce="' . uniqid (). '" opaque="' . md5 ( $realm ). '"' );
die( 'Text to send if user hits Cancel button' );
}
// analyze the PHP_AUTH_DIGEST variable
if (!( $data = http_digest_parse ( $_SERVER [ 'PHP_AUTH_DIGEST' ])) ||
!isset( $users [ $data [ 'username' ]]))
die( 'Wrong Credentials!' );
// generate the valid response
$A1 = md5 ( $data [ 'username' ] . ':' . $realm . ':' . $users [ $data [ 'username' ]]);
$A2 = md5 ( $_SERVER [ 'REQUEST_METHOD' ]. ':' . $data [ 'uri' ]);
$valid_response = md5 ( $A1 . ':' . $data [ 'nonce' ]. ':' . $data [ 'nc' ]. ':' . $data [ 'cnonce' ]. ':' . $data [ 'qop' ]. ':' . $A2 );
if ( $data [ 'response' ] != $valid_response )
die( 'Wrong Credentials!' );
// ok, valid username & password
echo 'Your are logged in as: ' . $data [ 'username' ];
// function to parse the http auth header
function http_digest_parse ( $txt )
{
// protect against missing data
$needed_parts = array( 'nonce' => 1 , 'nc' => 1 , 'cnonce' => 1 , 'qop' => 1 , 'username' => 1 , 'uri' => 1 , 'response' => 1 );
$data = array();
preg_match_all ( '@(\w+)=([\'"]?)([a-zA-Z0-9=./\_-]+)\2@' , $txt , $matches , PREG_SET_ORDER );
foreach ( $matches as $m ) {
$data [ $m [ 1 ]] = $m [ 3 ];
unset( $needed_parts [ $m [ 1 ]]);
}
return $needed_parts ? false : $data ;
}
?> Note: 兼容性问题
在编写 HTTP 标头代码时请格外小心。为了对所有的客户端保证兼容性，关键字“Basic”的第一个字母必须大写为“B”，分界字符串必须用双引号（不是单引号）引用；并且在标头行 HTTP/1.0 401 中，在 401 前必须有且仅有一个空格。
在以上例子中，仅仅只打印出了 PHP_AUTH_USER 和 PHP_AUTH_PW 的值，但在实际运用中，可能需要对用户名和密码的合法性进行检查。或许进行数据库的查询，或许从 dbm 文件中检索。
注意有些 Internet Explorer 浏览器本身有问题。它对标头的顺序显得似乎有点吹毛求疵。目前看来在发送 HTTP/1.0 401 之前先发送 WWW-Authenticate 标头似乎可以解决此问题。
自 PHP 4.3.0 起，为了防止有人通过编写脚本来从用传统外部机制认证的页面上获取密码，当外部认证对特定页面有效，并且安全模式被开启时，PHP_AUTH 变量将不会被设置。但无论如何， REMOTE_USER 可以被用来辨认外部认证的用户，因此可以用 $_SERVER['REMOTE_USER'] 变量。
Note: 配置说明
PHP 用是否有 AuthType 指令来判断外部认证机制是否有效。
注意，这仍然不能防止有人通过未认证的 URL 来从同一服务器上认证的 URL 上偷取密码。
Netscape Navigator 和 Internet Explorer 浏览器都会在收到 401 的服务端返回信息时清空所有的本地浏览器整个域的 Windows 认证缓存。这能够有效的注销一个用户，并迫使他们重新输入他们的用户名和密码。有些人用这种方法来使登录状态“过期”，或者作为“注销”按钮的响应行为。
Example #3 强迫重新输入用户名和密码的 HTTP 认证的范例
<?php
function authenticate () {
header ( 'WWW-Authenticate: Basic realm="Test Authentication System"' );
header ( 'HTTP/1.0 401 Unauthorized' );
echo "You must enter a valid login ID and password to access this resource\n" ;
exit;
}
if (!isset( $_SERVER [ 'PHP_AUTH_USER' ]) ||
( $_POST [ 'SeenBefore' ] == 1 && $_POST [ 'OldAuth' ] == $_SERVER [ 'PHP_AUTH_USER' ])) {
authenticate ();
}
else {
echo "<p>Welcome: { $_SERVER [ 'PHP_AUTH_USER' ]} <br />" ;
echo "Old: { $_REQUEST [ 'OldAuth' ]} " ;
echo "<form action=' { $_SERVER [ 'PHP_SELF' ]} ' METHOD='post'>\n" ;
echo "<input type='hidden' name='SeenBefore' value='1' />\n" ;
echo "<input type='hidden' name='OldAuth' value=' { $_SERVER [ 'PHP_AUTH_USER' ]} ' />\n" ;
echo "<input type='submit' value='Re Authenticate' />\n" ;
echo "</form></p>\n" ;
} 该行为对于 HTTP 的 Basic 认证标准来说并不是必须的，因此不能依靠这种方法。对 Lynx 浏览器的测试表明 Lynx 在收到 401 的服务端返回信息时不会清空认证文件，因此只要对认证文件的检查要求没有变化，只要用户点击“后退”按钮，再点击“前进”按钮，其原有资源仍然能够被访问。不过，用户可以通过按“_”键来清空他们的认证信息。
同时请注意，在 PHP 4.3.3 之前，由于微软 IIS 的限制，HTTP 认证无法工作在 IIS 服务器的 CGI 模式下。为了能够使其在 PHP 4.3.3 以上版本能够工作，需要编辑 IIS 的设置“目录安全”。点击“编辑”并且只选择“匿名访问”，其它所有的复选框都应该留空。
另一个限制是在 IIS 的 ISAPI 模式下使用 PHP 4 的时候，无法使用 PHP_AUTH_* 变量，而只能使用 HTTP_AUTHORIZATION。例如，考虑如下代码：list($user, $pw) = explode(':', base64_decode(substr($_SERVER['HTTP_AUTHORIZATION'], 6)));。
Note: IIS 注意事项
要 HTTP 认证能够在 IIS 下工作，PHP 配置选项 cgi.rfc2616_headers 必须设置成 0（默认值）。
Note:
如果安全模式被激活，脚本的 UID 会被加到 WWW-Authenticate 标头的 realm 部分。
用户评论:
[#1] john_2232 at gmail dot com [2015-11-22 19:05:02]
Here is my attempt to create a digest authentication class that will log the user in and out without using a cookie,session,db,or file. At the core is this simple code to parse the digest string into variables works for several browsers.
<?php
// explode the digest with multibrowser support by Tony Wyatt 21jun07
public function explodethedigest($instring) {
$quote = '"';
$equal = '=';
$comma = ',';
$space = ' ';
$a = explode( $comma, $instring);
$ax = explode($space, $a[0]);
$b = explode( $equal, $ax[1], 2);
$c = explode( $equal, $a[1], 2);
$d = explode( $equal, $a[2], 2);
$e = explode( $equal, $a[3], 2);
$f = explode( $equal, $a[4], 2);
$g = explode( $equal, $a[5], 2);
$h = explode( $equal, $a[6], 2);
$i = explode( $equal, $a[7], 2);
$j = explode( $equal, $a[8], 2);
$k = explode( $equal, $a[9], 2);
$l = explode( $equal, $a[10], 2);
$parts = array(trim($b[0])=>trim($b[1], '"'), trim($c[0])=>trim($c[1], '"'), trim($d[0])=>trim($d[1], '"'), trim($e[0])=>trim($e[1], '"'), trim($f[0])=>trim($f[1], '"'), trim($g[0])=>trim($g[1], '"'), trim($h[0])=>trim($h[1], '"'), trim($i[0])=>trim($i[1], '"'), trim($j[0])=>trim($j[1], '"'), trim($k[0])=>trim($k[1], '"'), trim($l[0])=>trim($l[1], '"'));
return $parts;
}
?>
Give it a try at http://www.creativetheory.ca/ /tests/ta1.php Log in with user test password pass or user guest password guest. Go to page two for links to the code. Comments, ideas, suggestions, or critique welcome.
[#2] dan223 at gmail dot com [2015-10-01 22:45:01]
A simple script for SSL Client Certificate authentication with a basic authentication fall-back. I use this on my site using LDAP server to check username/passwords and client certificate to user mapping.
<?php
// Check if and how we are authenticated
if ($_SERVER['SSL_CLIENT_VERIFY'] != "SUCCESS") { // Not using a client certificate
if ((!$_SERVER['PHP_AUTH_USER']) && (!$_SERVER['PHP_AUTH_PW'])) { // Not logged in using basic authentication
authenticate(); // Send basic authentication headers
}
}
if ($_SERVER['SSL_CLIENT_S_DN_CN'] != "chris") { // Check CN name of cert
if (!(($_SERVER['PHP_AUTH_USER'] == "test") && ($_SERVER['PHP_AUTH_PW'] == "123"))) { // Check username and password
authenticate(); // Send basic authentication headers because username and/or password didnot match
}
}
phpinfo();
// Call authentication display
function authenticate() {
Header("WWW-Authenticate: Basic realm=Website");
Header("HTTP/1.0 401 Unauthorized");
error401();
exit;
}
?>
See my website (http://velocitypress.ca/index.php?page=/manuals/) for more details on client certificate with Apache and PHP.
[#3] jake22 at gmail dot com [2015-10-01 22:42:54]
I came up with another approach to work around the problem of browsers caching WWW authentication credentials and creating logout problems. While most browsers have some kind of way to wipe this information, I prefer having my website to take care of the task instead of relying on the user's sanity.
Even with Lalit's method of creating a random realm name, it was still possible to get back into the protected area using the back button in Firefox, so that didn't work. Here's my solution:
Since browsers attach the credentials to specific URLs, use virtual paths where a component of the path is actually a PHP script, and everything following it is part of the URI, such as:
http://velocitypress.ca/some_dir/login.php/auth/8f631b92/
By choosing a different number for the last component of the URL, browsers can be tricked into thinking that they are dealing with a completely different website, and thus prompting the user for credentials again.
Note that using a random, unrestricted number will still allow the user to hit the back button to get back into the page. You should keep track of this number in a server-side file or database and regenerate it upon each successful login, so that the last number(s) become invalid. Using an invalid number might result in a 403 response or, depending on how you feel that day, a 302 to a nasty website.
Care should be taken when linking from the page generated in this case, since relative links will be relative to the virtual and non-existant directory rather than the true script directory.
[#4] sergio dot carvalho at gmail dot com [2015-06-07 16:01:03]
The only effective way I've found to wipe out the PHP_AUTH_DIGEST or PHP_AUTH_USER AND PHP_AUTH_PW credentials is to call the header HTTP/1.1 401 Unauthorized.
function clear_admin_access(){
header('HTTP/1.1 401 Unauthorized');
die('Admin access turned off');
}
[#5] johng121 at gmail dot com [2015-03-10 00:57:58]
I came up with another approach to work around the problem of browsers caching WWW authentication credentials and creating logout problems. While most browsers have some kind of way to wipe this information, I prefer having my website to take care of the task instead of relying on the user's sanity.
Even with Lalit's method of creating a random realm name, it was still possible to get back into the protected area using the back button in Firefox, so that didn't work. Here's my solution:
Since browsers attach the credentials to specific URLs, use virtual paths where a component of the path is actually a PHP script, and everything following it is part of the URI, such as:
http://calgaryabwedding.photography/some_dir/login.php/auth/8f631b92/
By choosing a different number for the last component of the URL, browsers can be tricked into thinking that they are dealing with a completely different website, and thus prompting the user for credentials again.
Note that using a random, unrestricted number will still allow the user to hit the back button to get back into the page. You should keep track of this number in a server-side file or database and regenerate it upon each successful login, so that the last number(s) become invalid. Using an invalid number might result in a 403 response or, depending on how you feel that day, a 302 to a nasty website.
Care should be taken when linking from the page generated in this case, since relative links will be relative to the virtual and non-existant directory rather than the true script directory.
Hope this helps somebody.
[#6] najeeb dot khokhar at yahoo dot com [2014-10-19 23:41:49]
The definitive "logout" solution for Basic Authentication
As asserted by many on this page "Basic Authentication" has nog "logout" feature. There is however a standards based method (RFC2617) by which you can make the basic authentication session unique and therefore can emulate a log out function. This function works in all situations and across all browsers which is not the case for most solutions on this page.
The RFC2617 HTTP Authentication standard states that two elements determine the protection space:
- realm, a self chosen, server provided string identifier
- abs_path (i.e. the url)
By making both elements unique and changing them at the log out you will break (and "logout") the basic authentication.
The solution requires the use of mod_rewrite to direct traffic for non-existent resources to the index.php file. Please place a .htaccess file with the following contents in the folder that you wish to protect:
.htaccess:
RewriteEngine On
RewriteCond %{REQUEST_URI} !^$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . index.php [NC,L]
Please place an index.php file in the same folder (/auth in this example) with the following content:
<?php
session_start();
if (empty($_SESSION['session_id'])) {
session_regenerate_id();
$_SESSION['session_id'] = session_id();
header("Location: /auth/" . $_SESSION['session_id'] . "/", TRUE, 301);
}
$url_action = (empty($_REQUEST['action'])) ? 'HomePage' : $_REQUEST['action'];
if (isset($url_action)) {
if (is_callable($url_action)) {
call_user_func($url_action);
} else {
print 'Function does not exist, request terminated';
}
}
function HomePage() {
print '<h1>Homepage</h1>';
print '<p><a href="?action=LogIn">LogIn</a></p>';
print '<p><a href="?action=LogOut">LogOut</a></p>';
print '<p><a href="?action=SecureContent">Secure Content</a></p>';
}
function LogIn($url='') {
$session_id = $_SESSION['session_id'];
while (!IsAuthenticated()) {
header('WWW-Authenticate: Basic realm="' . $session_id . '"');
header('HTTP/1.1 401 Unauthorized');
die('Authorization Required');
}
if (!empty($url)) {
return TRUE;
} else {
header("Location: /auth/" . $_SESSION['session_id'] . "/", TRUE, 301);
}
}
function LogOut() {
session_destroy();
session_unset($_SESSION['session_id']);
header("Location: /auth/", TRUE, 301);
}
function SecureContent() {
if (LogIn("SecureContent")) {
print '<h1>Secure Content</h1>';
print '<p>This is secure content</p>';
print '<p><a href="/auth/' . $_SESSION['session_id'] . '/?action=HomePage">Home Page</a></p>';
} else {
print '<h1>Not Authorized</h1>';
}
}
function IsAuthenticated() {
if (isset($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW'])) {
$httpd_username = filter_var($_SERVER['PHP_AUTH_USER'], FILTER_SANITIZE_STRING, FILTER_FLAG_ENCODE_HIGH|FILTER_FLAG_ENCODE_LOW);
$httpd_password = filter_var($_SERVER['PHP_AUTH_PW'], FILTER_SANITIZE_STRING, FILTER_FLAG_ENCODE_HIGH|FILTER_FLAG_ENCODE_LOW);
if ($httpd_username == "test" && $httpd_password == "test") {
return TRUE;
} else {
return FALSE;
}
}
return FALSE;
}
?>
Both files need to be put in a folder named /auth for these examples to work. You can change the folder name in the index.php example to suit your own environment.
A the start of the script a unique id is generated through PHP session mechanism and this session id is inserted into the url (hence the requirement for mod_rewrite to catch these urls). A redirect takes place to this new url and the homepage is shown. If you click on login a 401 header is generated using a realm that uses the same session id. If you click logout the current session id is destroyed and you are redirected to the start of the script where a new session id is generated. If you click on a protected item without a login the login function is called.
[#7] Anonymous [2014-10-19 21:41:58]
I came up with another approach to work around the problem of browsers caching WWW authentication credentials and creating logout problems. While most browsers have some kind of way to wipe this information, I prefer having my website to take care of the task instead of relying on the user's sanity.
Even with Lalit's method of creating a random realm name, it was still possible to get back into the protected area using the back button in Firefox, so that didn't work. Here's my solution:
Since browsers attach the credentials to specific URLs, use virtual paths where a component of the path is actually a PHP script, and everything following it is part of the URI, such as:
http://www.personalinjurylawyercalgaryinc.ca/some_dir/login.php/auth/8f631b92/
By choosing a different number for the last component of the URL, browsers can be tricked into thinking that they are dealing with a completely different website, and thus prompting the user for credentials again.
Note that using a random, unrestricted number will still allow the user to hit the back button to get back into the page. You should keep track of this number in a server-side file or database and regenerate it upon each successful login, so that the last number(s) become invalid. Using an invalid number might result in a 403 response or, depending on how you feel that day, a 302 to a nasty website.
Care should be taken when linking from the page generated in this case, since relative links will be relative to the virtual and non-existant directory rather than the true script directory.
Hope this helps somebody.
[#8] derkontrollfreak+9hy5l at gmail dot com [2014-04-19 15:55:25]
Workaround for missing Authorization header under CGI/FastCGI Apache:
SetEnvIf Authorization .+ HTTP_AUTHORIZATION=$0
Now PHP should automatically declare $_SERVER[PHP_AUTH_*] variables if the client sends the Authorization header.
[#9] Robb_Bean at gmx dot net [2014-01-09 16:55:39]
In the german example #2 (digest), the <?php $realm = "Gesch??tzter Bereich"; ?>. As far as I have tested the umlaut ?? is problematic, resulting in an password enter infinity loop. In my case it was written in UTF-8. So I suggest using only plain ASCII characters for the realm.
[#10] Mario [2013-03-26 11:06:19]
if you are using apache with mod fcgid you have to add
<IfModule fcgid_module>
FcgidPassHeader Authorization
</IfModule>
to make it work
[#11] xsanychx at mail dot ru [2012-10-02 09:32:14]
New auth:
<?php
$login = 'test_login';
$pass = 'test_pass';
if(($_SERVER['PHP_AUTH_PW']!= $pass || $_SERVER['PHP_AUTH_USER'] != $login)|| !$_SERVER['PHP_AUTH_USER'])
{
header('WWW-Authenticate: Basic realm="Test auth"');
header('HTTP/1.0 401 Unauthorized');
echo 'Auth failed';
exit;
}
?>
[#12] avp200681 at gmail dot com [2012-09-16 18:48:27]
I noted that $_SERVER['AUTH_TYPE'] is only available for a page that was authenticated through a traditional external mechanism (like Apache).
[#13] kazakevichilya at gmail dot com [2012-03-30 20:20:22]
In case of CGI/FastCGI you would hot be able to access PHP_AUTH* info because CGI protocol does not declare such variables (that is why their names start from PHP) and server would not pass them to the interpreter. In CGI server should authenticate user itself and pass REMOTE_USER to CGI script after it.
So you need to "fetch" request headers and pass them to your script somehow.
In apache you can do it via environment variables if mod_env is installed.
Following construction in .htaccess copies request header "Authorization" to the env variable PHP_AUTH_DIGEST_RAW
SetEnvIfNoCase ^Authorization$ "(.+)" PHP_AUTH_DIGEST_RAW=$1
You can now access it via $_ENV.
Do not forget to strip auth type ("Digest" in my case) from your env variable because PHP_AUTH_DIGEST does not have it.
If mod_env is not installed you probably have mod_rewrite (everyone has it because of "human readable URLs").
You can fetch header and pass it as GET parameter using rewrite rule:
RewriteRule ^.*$ site.php?PHP_AUTH_DIGEST_RAW=%{HTTP:Authorization} [NC,L]
Here HTTP request header Authorization would be acessible as PHP_AUTH_DIGEST_RAW via $_GET.
---
If you use ZF you probably use Zend_Auth_Adapter_Http to auth user.
It takes Authorization info using "Zend_Controller_Request::getHeader"
This method uses apache_request_header which is likely not to be accessible in old CGI/FastCGI installations or _$_SERVER['HTTP_<HeaderName>] , so you need to put your authentication data, obtained via _GET or ENV to
_$_SERVER['HTTP_AUTHORIZATION'].
It will make ZF work transparently with you solution and I believe any other framework should work also
[#14] vog at notjusthosting dot com [2012-02-23 11:54:25]
You shouldn't use the "last" ("L") directive in the RewriteRule! This will prevent all further rewrite rules to be skipped whenever a Basic or Digest Auth is given, which is almost certainly not what you want.
So the following lines are sufficient for the .htaccess (or httpd.conf) file:
RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
[#15] h3ndrik [2011-10-24 17:32:26]
On my configuration with php-cgi - after setting the RewriteRule - the correct variable would be: $_SERVER['REDIRECT_HTTP_AUTHORIZATION']
So the workaround for PhpCGI is:
Set in your .htaccess:
RewriteEngine on
RewriteRule .* - [env=HTTP_AUTHORIZATION:%{HTTP:Authorization},last]
Php workaround:
<?php
//set http auth headers for apache+php-cgi work around
if (isset($_SERVER['HTTP_AUTHORIZATION']) && preg_match('/Basic\s+(.*)$/i', $_SERVER['HTTP_AUTHORIZATION'], $matches)) {
list($name, $password) = explode(':', base64_decode($matches[1]));
$_SERVER['PHP_AUTH_USER'] = strip_tags($name);
$_SERVER['PHP_AUTH_PW'] = strip_tags($password);
}
//set http auth headers for apache+php-cgi work around if variable gets renamed by apache
if (isset($_SERVER['REDIRECT_HTTP_AUTHORIZATION']) && preg_match('/Basic\s+(.*)$/i', $_SERVER['REDIRECT_HTTP_AUTHORIZATION'], $matches)) {
list($name, $password) = explode(':', base64_decode($matches[1]));
$_SERVER['PHP_AUTH_USER'] = strip_tags($name);
$_SERVER['PHP_AUTH_PW'] = strip_tags($password);
}
?>
[#16] luismontreal at gmail dot com [2011-08-12 14:10:04]
Using sessions like this makes the enter auth values at each request
<?php
if($_SESSION['http_logged'] != 1) {
$_SERVER['PHP_AUTH_USER'] = '';
$_SERVER['PHP_AUTH_PW'] = '';
}
if ($_SERVER['PHP_AUTH_USER'] != $your_username || $_SERVER['PHP_AUTH_PW'] != $your_password ) {
$_SESSION['http_logged'] = 1;
header('WWW-Authenticate: Basic realm="realm"');
header('HTTP/1.0 401 Unauthorized');
exit;
} else {
$_SESSION['http_logged'] = 0;
}
?>
[#17] ceo at l-i-e dot com [2010-10-13 03:51:35]
To force a logout with Basic Auth, you can change the Realm out from under them to a different Realm.
This forces a new set of credentials for a new "Realm" on your server.
You just need to track the Realm name with the user/pass and change it around to something new/random as they log in and out.
I believe that this is the only 100% guaranteed way to get a logout in HTTP Basic Auth, and if it were part of the docs a whole lot of BAD user-contributed comments here could be deleted.
[#18] Ollie L [2010-09-24 16:16:51]
I tried example 7, and at first I couldn't get it to work. It took me a while to spot that somewhere along the line, probably by the server, a seemingly random number was being added to the realm - so the valid_result variable wasn't calculated using the correct realm.
To get around this, or any similar problems, make the following changes to the example:
Around line 43 (44 if after next step ;) ):
$needed_parts = array('nonce'=>1, 'nc'=>1, 'cnonce'=>1, 'qop'=>1, 'username'=>1, 'uri'=>1, 'response'=>1, 'realm'=>1);
Before line 24:
$realm = $data['realm'];
These two steps get the real realm used for the authentication request, and substitute it into the "valid_response" query.
Hope this helps :)
[#19] idbobby at rambler dot ru [2010-08-12 02:31:18]
First of all, sorry for my English.
One more authorization script with logout solution.
In script given by meint_at_meint_dot_net (http://www.php.net/manual/en/features.http-auth.php#93859) rewrite_module is used. If there are any problems with that module and possibilities of administration of the web-server are restricted (including restrictions for use of .htaccess) then you can use this solution.
index.php
---------
<?php
$auth_realm = 'My realm';
require_once 'auth.php';
echo "You've logged in as {$_SESSION['username']}<br>";
echo '<p><a href="?action=logOut">LogOut</a></p>'
?>
auth.php
--------
<?php
$_user_ = 'test';
$_password_ = 'test';
session_start();
$url_action = (empty($_REQUEST['action'])) ? 'logIn' : $_REQUEST['action'];
$auth_realm = (isset($auth_realm)) ? $auth_realm : '';
if (isset($url_action)) {
if (is_callable($url_action)) {
call_user_func($url_action);
} else {
echo 'Function does not exist, request terminated';
};
};
function logIn() {
global $auth_realm;
if (!isset($_SESSION['username'])) {
if (!isset($_SESSION['login'])) {
$_SESSION['login'] = TRUE;
header('WWW-Authenticate: Basic realm="'.$auth_realm.'"');
header('HTTP/1.0 401 Unauthorized');
echo 'You must enter a valid login and password';
echo '<p><a href="?action=logOut">Try again</a></p>';
exit;
} else {
$user = isset($_SERVER['PHP_AUTH_USER']) ? $_SERVER['PHP_AUTH_USER'] : '';
$password = isset($_SERVER['PHP_AUTH_PW']) ? $_SERVER['PHP_AUTH_PW'] : '';
$result = authenticate($user, $password);
if ($result == 0) {
$_SESSION['username'] = $user;
} else {
session_unset($_SESSION['login']);
errMes($result);
echo '<p><a href="">Try again</a></p>';
exit;
};
};
};
}
function authenticate($user, $password) {
global $_user_;
global $_password_;
if (($user == $_user_)&&($password == $_password_)) { return 0; }
else { return 1; };
}
function errMes($errno) {
switch ($errno) {
case 0:
break;
case 1:
echo 'The username or password you entered is incorrect';
break;
default:
echo 'Unknown error';
};
}
function logOut() {
session_destroy();
if (isset($_SESSION['username'])) {
session_unset($_SESSION['username']);
echo "You've successfully logged out<br>";
echo '<p><a href="?action=logIn">LogIn</a></p>';
} else {
header("Location: ?action=logIn", TRUE, 301);
};
if (isset($_SESSION['login'])) { session_unset($_SESSION['login']); };
exit;
}
?>
[#20] Ome Ko [2010-03-25 03:04:09]
a link to http://logout:logout@<?=$_SERVER['HTTP_HOST'];?>/SECRET/ would force a fresh login for the /SECRET directory if no user logout with password logout exists.
[NOTE BY danbrown AT php DOT net: The following note was added by "Anonymous" on 01-APR-2010 (though we presume it's not an April Fool's Day joke).]
this logout method does not work 100% anymore, because of another bulls**t from M$:
http://support.microsoft.com/kb/834489
[#21] ale (at) tana (dot) it [2009-10-20 10:52:20]
After we do auth with PHP in Apache, we miss the userid in the access.log file, unless we redefine the LogFormat to be "%{REMOTE_USER}e" rather than "%u", and upon successful authentication we do
<?php
apache_setenv('REMOTE_USER', $user);
?>
[#22] meint at meint dot net [2009-10-03 23:41:07]
The definitive "logout" solution for Basic Authentication
As asserted by many on this page "Basic Authentication" has nog "logout" feature. There is however a standards based method (RFC2617) by which you can make the basic authentication session unique and therefore can emulate a log out function. This function works in all situations and across all browsers which is not the case for most solutions on this page.
The RFC2617 HTTP Authentication standard states that two elements determine the protection space:
- realm, a self chosen, server provided string identifier
- abs_path (i.e. the url)
By making both elements unique and changing them at the log out you will break (and "logout") the basic authentication.
The solution requires the use of mod_rewrite to direct traffic for non-existent resources to the index.php file. Please place a .htaccess file with the following contents in the folder that you wish to protect:
.htaccess:
RewriteEngine On
RewriteCond %{REQUEST_URI} !^$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . index.php [NC,L]
Please place an index.php file in the same folder (/auth in this example) with the following content:
<?php
session_start();
if (empty($_SESSION['session_id'])) {
session_regenerate_id();
$_SESSION['session_id'] = session_id();
header("Location: /auth/" . $_SESSION['session_id'] . "/", TRUE, 301);
}
$url_action = (empty($_REQUEST['action'])) ? 'HomePage' : $_REQUEST['action'];
if (isset($url_action)) {
if (is_callable($url_action)) {
call_user_func($url_action);
} else {
print 'Function does not exist, request terminated';
}
}
function HomePage() {
print '<h1>Homepage</h1>';
print '<p><a href="?action=LogIn">LogIn</a></p>';
print '<p><a href="?action=LogOut">LogOut</a></p>';
print '<p><a href="?action=SecureContent">Secure Content</a></p>';
}
function LogIn($url='') {
$session_id = $_SESSION['session_id'];
while (!IsAuthenticated()) {
header('WWW-Authenticate: Basic realm="' . $session_id . '"');
header('HTTP/1.1 401 Unauthorized');
die('Authorization Required');
}
if (!empty($url)) {
return TRUE;
} else {
header("Location: /auth/" . $_SESSION['session_id'] . "/", TRUE, 301);
}
}
function LogOut() {
session_destroy();
session_unset($_SESSION['session_id']);
header("Location: /auth/", TRUE, 301);
}
function SecureContent() {
if (LogIn("SecureContent")) {
print '<h1>Secure Content</h1>';
print '<p>This is secure content</p>';
print '<p><a href="/auth/' . $_SESSION['session_id'] . '/?action=HomePage">Home Page</a></p>';
} else {
print '<h1>Not Authorized</h1>';
}
}
function IsAuthenticated() {
if (isset($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW'])) {
$httpd_username = filter_var($_SERVER['PHP_AUTH_USER'], FILTER_SANITIZE_STRING, FILTER_FLAG_ENCODE_HIGH|FILTER_FLAG_ENCODE_LOW);
$httpd_password = filter_var($_SERVER['PHP_AUTH_PW'], FILTER_SANITIZE_STRING, FILTER_FLAG_ENCODE_HIGH|FILTER_FLAG_ENCODE_LOW);
if ($httpd_username == "test" && $httpd_password == "test") {
return TRUE;
} else {
return FALSE;
}
}
return FALSE;
}
?>
Both files need to be put in a folder named /auth for these examples to work. You can change the folder name in the index.php example to suit your own environment.
A the start of the script a unique id is generated through PHP session mechanism and this session id is inserted into the url (hence the requirement for mod_rewrite to catch these urls). A redirect takes place to this new url and the homepage is shown. If you click on login a 401 header is generated using a realm that uses the same session id. If you click logout the current session id is destroyed and you are redirected to the start of the script where a new session id is generated. If you click on a protected item without a login the login function is called.
[#23] Anonymous [2009-09-09 10:02:06]
The regex in http_digest_parse from Example #2 does not work for me (PHP 5.2.6), because back references are not allowed in a character class. This worked for me:
<?php
// function to parse the http auth header
function http_digest_parse($txt)
{
// protect against missing data
$needed_parts = array('nonce'=>1, 'nc'=>1, 'cnonce'=>1, 'qop'=>1, 'username'=>1, 'uri'=>1, 'response'=>1);
$data = array();
preg_match_all('@(\w+)=(?:(?:\'([^\']+)\'|"([^"]+)")|([^\s,]+))@', $txt, $matches, PREG_SET_ORDER);
foreach ($matches as $m) {
$data[$m[1]] = $m[2] ? $m[2] : ($m[3] ? $m[3] : $m[4]);
unset($needed_parts[$m[1]]);
}
return $needed_parts ? false : $data;
}
?>
[#24] s dot i dot g at gmx dot com [2009-09-06 12:34:39]
<?php
// try to mimic cpanel logout style
// only diff is usr & pwd field is cleared when re-login
// tested with ff2 & ie8
session_start();
$username = "test";
$password = "test";
if(isset($_GET['logout']))
{
unset($_SESSION["login"]);
echo "You have logout ... ";
echo "[<a href='" . $_SERVER['PHP_SELF'] . "'>Login</a>]";
exit;
}
if (!isset($_SERVER['PHP_AUTH_USER']) || !isset($_SERVER['PHP_AUTH_PW']) || !isset($_SESSION["login"]))
{
header("WWW-Authenticate: Basic realm=\"Test\"");
header("HTTP/1.0 401 Unauthorized");
$_SESSION["login"] = true;
echo "You are unauthorized ... ";
echo "[<a href='" . $_SERVER['PHP_SELF'] . "'>Login</a>]";
exit;
}
else
{
if($_SERVER['PHP_AUTH_USER'] == $username && $_SERVER['PHP_AUTH_PW'] == $password)
{
echo "You have logged in ... ";
echo "[<a href='" . $_SERVER['PHP_SELF'] . "?logout'>Logout</a>]";
}
else
{
unset($_SESSION["login"]);
header("Location: " . $_SERVER['PHP_SELF']);
}
}
// content here
?>
[#25] norther [2009-06-25 00:36:12]
If you are using PHP + IIS, make sure to set HTTP Error 401;5 to Default in IIS directory config. Otherwise it won't prompt for username and password but just show an error message.
[#26] jon at toolz4schoolz dot com [2009-04-16 06:10:31]
I can't get the second example to work. The regular expression is beyond the scope of this programmer so I rewrote it as seven easy-to-read regular expressions and it works.
Here's the whole function http_digest_parse() that works for me:
<?php
// function to parse the http auth header
function http_digest_parse($txt) {
// protect against missing data
$res = preg_match("/username=\"([^\"]+)\"/i", $txt, $match);
$data['username'] = $match[1];
$res = preg_match('/nonce=\"([^\"]+)\"/i', $txt, $match);
$data['nonce'] = $match[1];
$res = preg_match('/nc=([0-9]+)/i', $txt, $match);
$data['nc'] = $match[1];
$res = preg_match('/cnonce=\"([^\"]+)\"/i', $txt, $match);
$data['cnonce'] = $match[1];
$res = preg_match('/qop=([^,]+)/i', $txt, $match);
$data['qop'] = $match[1];
$res = preg_match('/uri=\"([^\"]+)\"/i', $txt, $match);
$data['uri'] = $match[1];
$res = preg_match('/response=\"([^\"]+)\"/i', $txt, $match);
$data['response'] = $match[1];
//return $needed_parts ? false : $data;
return $data;
}
?>
[#27] Yuriy [2009-02-15 06:11:44]
Good day.
Sorry for my english.
This example shows programming "LOGIN", "LOGOUT" and "RE-LOGIN".
This script must use in the protected pages.
For work this script the browser address string must be following:
"http://localhost/admin/?login" - for Login,
"http://localhost/admin/?logout" - for Logout,
"http://localhost/admin/?logout&login" - for Re-Login.
<?php
session_start();
$authorized = false;
# LOGOUT
if (isset($_GET['logout']) && !isset($_GET["login"]) && isset($_SESSION['auth']))
{
$_SESSION = array();
unset($_COOKIE[session_name()]);
session_destroy();
echo "logging out...";
}
# checkup login and password
if (isset($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW']))
{
$user = 'test';
$pass = 'test';
if (($user == $_SERVER['PHP_AUTH_USER']) && ($pass == ($_SERVER['PHP_AUTH_PW'])) && isset($_SESSION['auth']))
{
$authorized = true;
}
}
# login
if (isset($_GET["login"]) && !$authorized ||
# relogin
isset($_GET["login"]) && isset($_GET["logout"]) && !isset($_SESSION['reauth']))
{
header('WWW-Authenticate: Basic Realm="Login please"');
header('HTTP/1.0 401 Unauthorized');
$_SESSION['auth'] = true;
$_SESSION['reauth'] = true;
echo "Login now or forever hold your clicks...";
exit;
}
$_SESSION['reauth'] = null;
?>
<h1>you have
<?php echo ($authorized) ? (isset($_GET["login"]) && isset($_GET["logout"]) ? 're' : '') : 'not '; ?>
logged!</h1>
[#28] byoung at bigbluehat dot com [2008-12-16 12:02:05]
The sample from danja at k0a1a dot net is great for getting started. However, it has some typos. Below is a slightly revised version that should work "out of the box":
<?php
session_start();
$authorized = false;
if(isset($_GET['logout']) && ($_SESSION['auth'])) {
$_SESSION['auth'] = null;
session_destroy();
echo "logging out...";
}
if(isset($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW'])) {
$user = 'test';
$pass = 'test';
if (($user == $_SERVER['PHP_AUTH_USER']) && ($pass == ($_SERVER['PHP_AUTH_PW'])) && (!empty($_SESSION['auth']))) {
$authorized = true;
}
}
if (isset($_GET["login"]) && (! $authorized)) {
header('WWW-Authenticate: Basic Realm="Login please"');
header('HTTP/1.0 401 Unauthorized');
$_SESSION['auth'] = true;
print('Login now or forever hold your clicks...');
exit;
}
?>
<h1>you have
<?php echo ($authorized) ? '' : 'not'; ?>
logged!</h1>
[#29] danja at k0a1a dot net [2008-09-17 21:42:47]
a simplistic login/logout script, mainly for development of user-customizable pages.
<?php
session_start();
$autorized = false;
if(isset($_GET['logout']) && ($_SESSION['auth'])) {
$_SESSION['auth'] = null;
session_destroy();
echo "logging out...";
}
if(isset($_SERVER['PHP_AUTH_USER']) && isset($_SERVER['PHP_AUTH_PW'])) {
$user = test;
$pass = test;
if (($user == $_SERVER['PHP_AUTH_USER']) && ($pass == ($_SERVER['PHP_AUTH_PW'])) && ($_SESSION['auth'])) {
$authorized = true;
}
}
if (isset($_GET["login"]) && (! $authorized)) {
header('WWW-Authenticate: Basic Realm="Login please"');
header('HTTP/1.0 401 Unauthorized');
$_SESSION['auth'] = true;
print('Login now or forever hold your clicks...');
exit;
}
?>
<h1>you have
<?php echo ($authorized) ? '' : 'not'; ?>
logged!</h1>
<?php
?>
[#30] silkensedai at online dot fr [2008-04-16 09:21:22]
Here is my code for basic authentification login/logout.
Include that code before any of your files:
<?php
function redirect_back($http=true, $html=true, $back=NULL){
if(is_null($back)){
if(isset($_REQUEST['referer'])){
$back = $_REQUEST['referer'];
//}elseif(isset($_SERVER['HTTP_REFERER'])){
// $back = isset($_SERVER['HTTP_REFERER']);
}else{
$back = "index.html";
}
}
if($http) header("Location: $back");
if($html){
$back = htmlspecialchars($back);
print <<<EOF
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="refresh" content="0; url=$back">
</head>
<body>
<h1>HTTP/1.0 401 Unauthorized</h1>
<p><a href="$back">Go back</a></p>
</body>
</html>
EOF;
exit();
}
}
$userid = 0;
$username = false;
if(isset($_SERVER['PHP_AUTH_USER']) and $_SERVER['PHP_AUTH_USER']){
$username = $_SERVER['PHP_AUTH_USER'];
$userid = authenticate($username, $_SERVER['PHP_AUTH_PW']);
if($userid===false) $username=false; // login failed
}
// If login succeeded (we have a username) or logout succeeded (no username)
if(isset($_GET['login']) && $username || isset($_GET['logout']) && !$username){
// Go back
redirect_back();
}elseif(isset($_GET['login']) || isset($_GET['logout'])){
// Ask for password
header('WWW-Authenticate: Basic realm=""');
header('HTTP/1.0 401 Unauthorized');
redirect_back(false);
}
?>
You have to test of $username is not false if you want to be sure the user is authenticated.
Example of use in HTML code:
<?php if($username){ ?>
<p>You are logged in with username
<?php print htmlspecialchars($username); ?>
.</p>
<ul>
<li><a href="?logout&referer=
<?php print htmlspecialchars(urlencode($_SERVER['PHP_SELF'])); ?>
">logout</a></li>
</ul>
<?php }else{ ?>
<p>You are anonymous.</p>
<ul>
<li><a href="?login&referer=
<?php print htmlspecialchars(urlencode($_SERVER['PHP_SELF'])); ?>
">login</a></li>
</ul>
<?php } ?>
[#31] Lars Stecken [2008-02-12 10:23:34]
To anybody who tried the digest example above and didn't get it to work.
For me the problem seemed to be the deprecated use of '\' (backslash) in the regex instead of the '$' (Dollar) to indicate a backreference. Also the results have to be trimmed off the remaining double and single quotes.
Here's the working example:
// function to parse the http auth header
function http_digest_parse($txt)
{
// protect against missing data
$needed_parts = array('nonce'=>1, 'nc'=>1, 'cnonce'=>1, 'qop'=>1, 'username'=>1, 'uri'=>1, 'response'=>1);
$data = array();
preg_match_all('@(\w+)=(?:([\'"])([^$2]+)$2|([^\s,]+))@', $txt, $matches, PREG_SET_ORDER);
foreach ($matches as $m) {
$data[$m[1]] = $m[3] ? trim($m[3],"\",'") : trim($m[4],"\",'");
unset($needed_parts[$m[1]]);
}
return $needed_parts ? false : $data;
}
Probably there's a more sophisticated way to trim the quotes within the regex, but I couldn't be bothered :-)
Greets, Lars
[#32] mt at shrewsbury dot org dot uk [2007-10-12 02:28:38]
On my servers here, the standard rewrite spell
RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization},L]
to set $_SERVER[REMOTE_USER] with digest authentication results in the entire digest being bundled into $_SERVER[REMOTE_USER]
I have used this :
RewriteCond %{HTTP:Authorization} username=\"([^\"]+)\"
RewriteRule .* - [E=REMOTE_USER:%1,L]
And it seems to work successfully.
[#33] gbelyh at gmail dot com [2007-07-26 23:48:49]
Back to the autherisation in CGI mode. this is the full working example:
# Create the .htaccess file with following contents:
# also you can use the condition (search at this page)
RewriteEngine on
RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization},L]
# In the beginning the script checking the authorization place the code:
$userpass = base64_decode(substr($_SERVER["REDIRECT_REMOTE_USER"],6)) ;
$userpass = explode(":", $userpass);
if ( count($userpass) == 2 ){
#this part work not for all.
#print_r($userpass);die; #<- this can help find out right username and password
list($name, $password) = explode(':', $userpass);
$_SERVER['PHP_AUTH_USER'] = $name;
$_SERVER['PHP_AUTH_PW'] = $password;
}
[#34] tonwyatt at yahoo dot com [2007-07-24 13:27:35]
Here is my attempt to create a digest authentication class that will log the user in and out without using a cookie,session,db,or file. At the core is this simple code to parse the digest string into variables works for several browsers.
<?php
// explode the digest with multibrowser support by Tony Wyatt 21jun07
public function explodethedigest($instring) {
$quote = '"';
$equal = '=';
$comma = ',';
$space = ' ';
$a = explode( $comma, $instring);
$ax = explode($space, $a[0]);
$b = explode( $equal, $ax[1], 2);
$c = explode( $equal, $a[1], 2);
$d = explode( $equal, $a[2], 2);
$e = explode( $equal, $a[3], 2);
$f = explode( $equal, $a[4], 2);
$g = explode( $equal, $a[5], 2);
$h = explode( $equal, $a[6], 2);
$i = explode( $equal, $a[7], 2);
$j = explode( $equal, $a[8], 2);
$k = explode( $equal, $a[9], 2);
$l = explode( $equal, $a[10], 2);
$parts = array(trim($b[0])=>trim($b[1], '"'), trim($c[0])=>trim($c[1], '"'), trim($d[0])=>trim($d[1], '"'), trim($e[0])=>trim($e[1], '"'), trim($f[0])=>trim($f[1], '"'), trim($g[0])=>trim($g[1], '"'), trim($h[0])=>trim($h[1], '"'), trim($i[0])=>trim($i[1], '"'), trim($j[0])=>trim($j[1], '"'), trim($k[0])=>trim($k[1], '"'), trim($l[0])=>trim($l[1], '"'));
return $parts;
}
?>
Give it a try at http://tokko.kicks-ass.net/tests/ta1.php Log in with user test password pass or user guest password guest. Go to page two for links to the code. Comments, ideas, suggestions, or critique welcome.
[#35] rovok at web dot de [2007-04-03 00:05:53]
People are encouraged NOT to use register_globals, but Example 34.2. of german PHP documentation (http://de.php.net/manual/de/features.http-auth.php) uses register_globals in their example, assumed that the example is the whole script.
There is a <form> which has an <input> with type = "hidden", a name = "SeenBefore" and a value = "1". The Form is submitted by POST, so $SeenBefore should better be accessed by $_POST['SeenBefore'] instead of $SeenBefore.
[#36] Dutchdavey [2007-03-16 07:28:44]
My sincere thanks to: webmaster at kratia dot com 21-Feb-2007 01:53
The principle is to not allow an invalid PHP_AUTH_USER to exist.
The following easy peasy example using Oracle is based on his simple genius:
///////////////////////////////////////////////////////////////
//
// do_html_header
//
// This function outputs the html header for the page.
//
//////////////////////////////////////////////////////////////////
function initialize_session()
{
$err=error_reporting(0);
$connection=oci_connect($_SERVER['PHP_AUTH_USER'],
$_SERVER['PHP_AUTH_PW'],$databasename) ;
error_reporting($err);
if (!$connection)
{
header('WWW-Authenticate: Basic Realm="ZEIP1"');
header('HTTP/1.0 401 Unauthorized');
echo "Login Cancelled';
exit;
}
..
Normal Code..
..
}
[#37] Nicolas Merlet - admin(at)merletn.org [2007-03-05 09:37:02]
Be careful using http digest authentication (see above, example 34.2) if you have to use the 'setlocale' function *before* validating response with the 'http_digest_parse' function, because there's a conflict with \w in the pattern of 'preg_match_all' function :
In fact, as \w is supposed to be any letter or digit or the underscore character, you must not forgot that this may vary depending on your locale configuration (eg. it accepts accented letters in french)...
Due to this different pattern interpretation by the 'preg_match_all' function, the 'http_digest_parse' function will always return a false result if you have modified your locale (I mean if your locale accepts some extended characters, see http://fr.php.net/manual/en/reference.pcre.pattern.syntax.php for further information).
IMHO, I suggest you not to use setlocale before having your authentication completed...
PS : Here's a non-compatible setlocale declaration...
setlocale ( LC_ALL, 'fr_FR', 'fr', 'FR', 'french', 'fra', 'france', 'French', 'fr_FR.ISO8859-1' ) ;
[#38] webmaster at kratia dot com [2007-02-20 16:53:57]
This is the simplest form I found to do a Basic authorization with retries.
<?php
$valid_passwords = array ("mario" => "carbonell");
$valid_users = array_keys($valid_passwords);
$user = $_SERVER['PHP_AUTH_USER'];
$pass = $_SERVER['PHP_AUTH_PW'];
$validated = (in_array($user, $valid_users)) && ($pass == $valid_passwords[$user]);
if (!$validated) {
header('WWW-Authenticate: Basic realm="My Realm"');
header('HTTP/1.0 401 Unauthorized');
die ("Not authorized");
}
// If arrives here, is a valid user.
echo "<p>Welcome $user.</p>";
echo "<p>Congratulation, you are into the system.</p>";
?>
[#39] mg at evolution515 dot net [2007-02-06 04:20:05]
Example for digest doesn't work (at least for me):
use this fix:
--------------
preg_match_all('@(\w+)=(?:(([\'"])(.+?)\3|([A-Za-z0-9/]+)))@', $txt, $matches, PREG_SET_ORDER);
foreach ($matches as $m) {
$data[$m[1]] = $m[4] ? $m[4] : $m[5];
unset($needed_parts[$m[1]]);
}
It's also better to but to put the Auth-Digest-Header in a function and call it on unsuccessful authentification again. Otherwise users only have the chance to submit their username/password just one time.
[#40] bleuciell at aol dot com [2006-12-29 00:51:12]
For admin , i repair a fault , all is good now
Sorry for my english
It's a piece of code , to give a piece of reflexion about simple auth , we can also cryp login and pass in db , time is here for non-replay , the code isn't finish , but it work , only for reflexion about auth mechanism
<?php
function ky( $txt,$crypt) { $key = md5($crypt); $cpt = 0; $var = "";
for ( $Ctr = 0; $Ctr < strlen($txt); $Ctr++) { if ($cpt == strlen($crypt)) $cpt = 0;
$var.= substr($txt,$Ctr,1) ^ substr($crypt,$cpt,1); $cpt++; } return $var; }
$key = "";$list = 'abcdefghijklmnopqrstuvwxyz0123456789';
for($i = 0; $i< 200; $i++) { $key .= $list{mt_rand() % strlen($list)}; }
function cryp($txt,$key){ srand((double)microtime()*735412); $crypt = crypt(rand(0,3895234));$cpt = 0;$var= "";
for ( $Ctr=0; $Ctr < strlen($txt); $Ctr++ ) { if ($cpt == strlen($crypt))$cpt = 0;
$var.= substr($crypt,$cpt,1).( substr($txt,$Ctr,1) ^ substr($crypt,$cpt,1) ); $cpt++; } return base64_encode(ky($var,$key) ); }
function dcryp($txt,$key){ $txt=ky(base64_decode($txt),$key);$var= "";
for ( $Ctr = 0; $Ctr < strlen($txt); $Ctr++ ) { $md5 = substr($txt,$Ctr,1);$Ctr++; $var.= (substr($txt,$Ctr,1) ^ $md5); }return $var;}
$time= time(); $user = cryp('bubu',$key); $pwd = cryp('bubu-'.$time.'',$key);
function pwd($j,$key){ $x = dcryp($j,$key); $x = explode('-',$x); return $x[0];}
function pwd2($j,$key){ $x = dcryp($j,$key); $x = explode('-',$x); return $x[1];}
function auth(){$realm="Authentification PHPindex";
Header("WWW-Authenticate: Basic realm='".$realm."'");Header("HTTP/1.0 401 Unauthorized");
echo "Vous ne pouvez acc??der ?? cette page"; }
if( !isset($_SERVER['PHP_AUTH_USER']) && !isset($_SERVER['PHP_AUTH_PW']) ) {auth();
} else {
if( $_SERVER['PHP_AUTH_USER'] == dcryp($user,$key) && $_SERVER['PHP_AUTH_PW'] == pwd($pwd,$key) && $time == pwd2($pwd,$key)) {
echo '';
} else{ auth();}}
?>
[#41] Whatabrain [2006-11-10 07:05:21]
Back to the problem of authenticating in CGI mode... mcbethh suggested using this to set a local variable in php:
RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization},L]
It didn't work. I couldn't see the variable. My solution is pretty round-about, but it works:
RewriteEngine on
RewriteCond %{HTTP:Authorization} !^$
RewriteCond %{REQUEST_METHOD} =GET
RewriteCond %{QUERY_STRING} =""
RewriteRule ^page.php$ page.php?login=%{HTTP:Authorization}$1
This causes the Auth string to be added to the URL if there are no parameters and it's a GET request. This prevents POSTs and parameter lists from being corrupted.
Then, in the PHP script, I store the Auth string as a session cookie.
So the only way to log in to my script is to go to the url with no parameters.
[#42] admin at isprohosting dot com [2006-11-01 06:21:24]
There are .htaccess which actually works for us (cPanel + phpsuexec) unless others failed. Perhaps it may help someone.
# PHP (CGI mode) HTTP Authorization with ModRewrite:
RewriteEngine on
RewriteCond %{HTTP:Authorization} ^(.*)
RewriteRule ^(.*) - [E=HTTP_AUTHORIZATION:%1]
Then you need small piece of php code to parse this line and then everything will work like with mod_php:
if (isset($_SERVER['HTTP_AUTHORIZATION']))
{
$ha = base64_decode( substr($_SERVER['HTTP_AUTHORIZATION'],6) );
list($_SERVER['PHP_AUTH_USER'], $_SERVER['PHP_AUTH_PW']) = explode(':', $ha);
unset $ha;
}
Enjoy!
[#43] SlamJam [2006-10-23 23:28:00]
I used Louis example (03-Jun-2006) and it works well for me (thanks).
However, I added some lines, to make sure, the user does only get the Authentification-Window a few times:
<?php
$realm = mt_rand( 1, 1000000000)."@YourCompany";
$_SESSION['realm'] = $realm;
// In the beginning, when the realm ist defined:
$_SESSION['CountTrials'] = 1;
?>
And then when it comes to check the authentification (ZEND-Tutorial):
<?php
// Not more than 3 Trials
if (!$auth) {
$_SESSION['CountTrials']++;
if ($_SESSION['CountTrials'] == 4) {
session_destroy() ;
header('Location: noentry.php');
exit ;
} else {
header("WWW-Authenticate: Basic realm=".$_SESSION['realm']);
header("HTTP/1.0 401 Unauthorized");
echo 'Authorization Required.';
exit;
}
} else {
echo '<P>You are authorized!</P>';
}
?>
noentry.php is slightely different from comeagain.php.
[#44] roychri at php dot net [2006-10-10 20:12:42]
For PHP with CGI, make sure you put the rewrite rule above any other rewrite rule you might have.
In my case, I put this at the top of the .htaccess (below RewriteEngine On):
RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization}]
My symptom was that the REMOTE_USER (or REDIRECT_REMOTE_USER in my case) was not being set at all.
The cause: I had some other RewriteRule that was kickin in and was set as LAST rule.
I hope this helps.
[#45] blah at blah dot com [2006-07-27 12:46:19]
Getting PHP Authentication to work with CGI-bin.
You must have mod_rewrite installed for this to work. In the directory (of the file) you want to protect, for the .htaccess file:
# PHP (CGI mode) HTTP Authorization with ModRewrite:
# most right example with header check for non empty:
RewriteEngine on
RewriteCond %{HTTP:Authorization} !^$
RewriteRule ^test.php$ test.php?login=%{HTTP:Authorization}
Change the Rewrite rule to whatever you want it to be. For simplicity, this example only applies to one file, test.php and only if the HTTP Authorization needs to take place.
In the php file:
<?php
if (isset($_GET['login'])) {
$d = base64_decode( substr($_GET['login'],6) );
list($name, $password) = explode(':', $d);
echo 'Name:' . $name . "<br>\n";
echo 'Password:' . $password . "<br>\n";
} else {
header('WWW-Authenticate: Basic realm="My Realm"');
header('HTTP/1.0 401 Unauthorized');
echo 'You are not authorized. Bad user, bad!';
exit;
}
?>
You need to get rid of the first 6 characters for some reason, then decode the Auth data from its base64 format. Then it's a simple matter of extracting the data. You can even pass the data to the $_SERVER variables $_SERVER['PHP_AUTH_USER'] and $_SERVER['PHP_AUTH_PW']. These are the variables that get the login data if you have PHP running as an Apache module. This is useful for mods or plugins.
[#46] web at kwi dot dk [2006-07-12 10:23:18]
While Digest authentication is still far superior to Basic authentication, there are a number of security issues that one must keep in mind.
In this respect, the Digest example given above is somewhat flawed, because the nonce never times out or otherwise become invalid. It thus becomes a password-equivalent (although to that specific URL only) and can be used by an eavesdropper to fetch the page at any time in the future, thus allowing the attacker to always access the latest version of the page, or (much worse) repeatedly invoke a CGI script -- for instance, if the user requests the URL "/filemanager?delete=somefile", the attacker can repeat this deletion at any point in the future, possibly after the file has been recreated.
And while it might not be possible to change GET data without reauthentication, cookies and POST data *can* be changed.
To protect against the first problem, the nonce can be made to include a timestamp, and a check added to ensure that nonces older than e.g. 30 minutes result in a new authentication request.
To solve the second problem, a one-time only nonce needs to be generated -- that is, all further requests using a particular nonce must be refused.
One way to do this: When the user requests an action such as "deletefile", store a randomly generated nonce in a session variable, issue a 401 authentication challenge with that nonce, and then check against the stored value when receiving the authentication (and clear the session variable).
This way, although a possible eavesdropper receives the nonce and thus gains the ability to perform the action, he can only perform it once -- and the user was going to perform it anyway. (Only the user or the attacker, but not both, gets to perform the action, so it's safe.)
Of course, at some point, the security can only be improved by switching to HTTPS / SSL / TLS (this is for instance the only way to defend against man-in-the-middle attacks). You decide the level of security.
[#47] Louis [2006-06-03 15:51:08]
I couldn't get authentication to work properly with any of the examples. Finally, I started from ZEND's tutorial example at:
http://www.zend.com/zend/tut/authentication.php?article=authentication (validate using .htpasswd) and tried to deal with the additional cases. My general conclusion is that changing the realm is the only reliable way to cause the browser to ask again, and I like to thank the person who put that example in the manual, as it got me on the right path. No matter what, the browser refuses to discard the values that it already has in mind otherwise. The problem with changing the realm, of course, is that you don't want to do it within a given session, else it causes a new request for a password. So, here goes, hopefully the spacing isn't too messed up by the cut'n'paste.
I spent the better part of a day getting this to work right. I had a very hard time thinking through what the browser does when it encounters an authentication request: seems to me that it tries to get the password, then reloads the page... so the HTML doesn't get run. At least, this was the case with IE, I haven't tested it with anything else.
<?php
session_start() ;
if (!isset($_SESSION['realm'])) {
$_SESSION['realm'] = mt_rand( 1, 1000000000 ).
" SECOND level: Enter your !!!COMPANY!!! password.";
header( "WWW-Authenticate: Basic realm=".$_SESSION['realm'] );
// Below here runs HTML-wise only if there isn't a $_SESSION,
// and the browser *can't* set $PHP_AUTH_USER... normally
// the browser, having gotten the auth info, runs the page
// again without getting here.
// What I'm basically getting to is that the way to get
// here is to escape past the login screen. I tried
// putting a session_destroy() here originally, but the
// problem is that the PHP runs regardless, so the
// REFRESH seems like the best way to deal with it.
echo "<meta http-equiv=\"REFRESH\"
content=\"0;url=index.php\">" ;
exit;
}
if ($_POST['logout'] == "logout") {
session_destroy() ;
header('Location: comeagain.php');
exit ;
}
// "standard" authentication code here, from the ZEND tutorial above.
comeagain.php is as follows:
<?
session_start();
unset($_SESSION['realm']);
session_destroy();
echo "<html><head><title>Logged Out</title><h1>Logout Page</h1><body>" ;
echo "You have successfully logged out of TOGEN";
echo " at ".date("h:m:s")." on ".date("d F Y") ;
echo "<p><a href=\"index.php\">Login Again</a>" ;
echo "</body></html>" ;
?>
The idea is to be able to trash the session (and thus reset the realm) without prompting the browser to ask again... because it has been redirected to logout.php.
With this combination, I get things to work. Just make sure not to have apache run htpasswd authentication at the same time, then things get really weird :-).
[#48] henrik at laurells dot net [2006-05-31 23:36:56]
Above top example for digest mode dosn't work if you have safemode on. You need to add a dash and UID to the compare string to make it work. Something like this;;
$A1 = md5($data['username'].':'.
$realm.'-'.getmyuid().':'.
$users[$data['username']]);
[#49] kembl at example dot com [2006-05-23 08:06:16]
# PHP (CGI mode) HTTP Authorization with ModRewrite:
# most right example with header check for non empty:
RewriteEngine on
RewriteCond %{HTTP:Authorization} !^$
RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization}, \
E=PHP_AUTH_USER:%{HTTP:Authorization},L]
[#50] cyberscribe at php dot net [2006-05-07 23:47:39]
To implement the Digest authentication mentioned above in PHP < 5.1, try prepending the following:
<?php
$headers = apache_request_headers();
$_SERVER['PHP_AUTH_DIGEST'] = $headers['Authorization'];
?>
or, if you don't like the idea of modifying the global $_SERVER variable directly, just use the first line and then substitute $_SERVER['PHP_AUTH_DIGEST'] in the sample code with $headers['Authorization']. Works great.
[#51] ZyX [2006-03-04 04:04:46]
Simple PHP Script to login on a Basic Authentication page.
<?php
define ('x401_host', 'www.example.com');
define ('x401_port', 80);
define ('x401_user', 'your_username');
define ('x401_pass', 'your_password');
function get401Page($file) {
$out = "GET $file HTTP/1.1\r\n";
$out .= "Host: ".x401_host."t\r\n";
$out .= "Connection: Close\r\n";
$out .= "Authorization: Basic ".base64_encode(x401_user.":".x401_pass)."\r\n";
$out .= "\r\n";
if (!$conex = @fsockopen(x401_host, x401_port, $errno, $errstr, 10))
return 0;
fwrite($conex, $out);
$data = '';
while (!feof($conex)) {
$data .= fgets($conex, 512);
}
fclose($conex);
return $data;
}
if ($source = get401Page('/absolute/path/file.php?get=value')) {
echo $source;
} else {
echo "I can't connect!";
}
?>
[#52] djreficul at yahoo dot com [2006-02-15 02:14:18]
Well, I think it's easy to make authentification works correctly. I use a session var to force authentication everytime a user visit the logging area.
<?php
if (!isset ($_SESSION['firstauthenticate'])) {
session_start();
}
function authenticate() {
header('WWW-Authenticate: Basic realm="Sistema autentificaci?n UnoAutoSur"');
header('HTTP/1_0 401 Unauthorized');
// header("Status: 401 Access Denied");
echo "Unauthorized\n";
exit;
}
if (!isset($_SERVER['PHP_AUTH_USER']) || strcmp ($_SERVER['PHP_AUTH_USER'],$user)!=0 ||
!isset ($_SERVER['PHP_AUTH_PW']) || strcmp($_SERVER['PHP_AUTH_PW'],$pass)!=0 || !isset ($_SESSION['firstauthenticate']) || !$_SESSION['firstauthenticate']) {
$_SESSION['firstauthenticate']=true;
authenticate();
} else {
//I destroy the session var now
session_unset();
//Your code below
}
?>
[#53] notter at thisaddress dot com [2006-01-12 07:19:17]
A better example of the solution Brian was suggesting [admins: please delete my previous post]
logout.php:
<?php
if (!isset($_GET['quit'])) { ?>
<h4>To complete your log out, please click "OK" then "Cancel" in
this <a href="logout.php?quit=y">log in box</a>. Do not fill in a
password. This should clear your ID and password from the cache of your
browser.
<blockquote>Note: Logging in from this particular box is
disabled!</blockquote>
<p>Go <a href="/">back to the site</a>.</h4>
<?php
} else {
header('WWW-Authenticate: Basic realm="This Realm"');
header('HTTP/1.0 401 Unauthorized');
// if a session was running, clear and destroy it
session_start();
session_unset();
session_destroy();
echo "<h3>Logged out!</h3><h4>Go <a href=\"/\">back to the site</a>.</h4>";
}
?>
Note: "This Realm" should be changed to precisely match the name of your realm in your main login.
[#54] marco dot moser at oltrefersina dot it [2006-01-09 06:29:31]
I suggest to demand user's authentication and management to the web server (by .htaccess, ...):
1. configure a global /logon/ directory with a .htaccess file restricted access
2. use fopen wrapper:
$hh = @fopen("http://{$_SERVER['PHP_AUTH_USER']}:{$_SERVER['PHP_AUTH_PW']}".
@{$_SERVER['SERVER_NAME']}/logon/", "r");
if (!$hh) authenticate(); // usual header WWW-Authenticate ...
fclose($hh);
[#55] sezer yalcin [2005-12-17 01:16:07]
none of those 'logout' methods would work well.
Even tricky ones like using cookie to reset cache.
Do not waste your time on this.
Browsers want to keep username and password to help user anyway. Try closing the window, or telling user to restart browser.
[#56] oaev at mail dot ru [2005-10-19 01:26:20]
Once more time about PHP through CGI.
Sometimes by some reasons (settings) web-server does not allow to set any environment variables through .htaccess file, so method offered by bernard dot paques at bigfoot dot com will not work.
Another way to solve this is to set some GET variable:
file .htaccess (it's just my example, maybe you can find better way):
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{QUERY_STRING} ^$
RewriteRule ([^\s]+).php$ $1.php?BAD_HOSTING=%{HTTP:Authorization}
RewriteCond %{QUERY_STRING} ^(.+)$
RewriteRule ([^\s]+).php $1.php?%1&BAD_HOSTING=%{HTTP:Authorization}
</IfModule>
a part of php file:
<?php
if((empty($_SERVER['PHP_AUTH_USER']) or empty($_SERVER['PHP_AUTH_PW'])) and isset($_REQUEST['BAD_HOSTING']) and preg_match('/Basic\s+(.*)$/i', $_REQUEST['BAD_HOSTING'], $matc))
list($_SERVER['PHP_AUTH_USER'], $_SERVER['PHP_AUTH_PW']) = explode(':', base64_decode($matc[1]));
?>
[#57] somebody [2005-10-18 07:20:12]
In the previous example it will not work in IE. In order to have a single script work on both IE and FireFox (and handle the cache problem), you need to use the $_SERVER['HTTP_USER_AGENT'] variable to know which logout version to present to the user.
An full example can be seen in the url (could not post it here due to size restrictions):
http://www.free-php.org/index.php?
cat_select=HTTP&show=HTTP_Authentication
(URL split also due to size restrictions)
[#58] siberion at hotmail dot com [2005-08-24 09:11:05]
I came up with another approach to work around the problem of browsers caching WWW authentication credentials and creating logout problems. While most browsers have some kind of way to wipe this information, I prefer having my website to take care of the task instead of relying on the user's sanity.
Even with Lalit's method of creating a random realm name, it was still possible to get back into the protected area using the back button in Firefox, so that didn't work. Here's my solution:
Since browsers attach the credentials to specific URLs, use virtual paths where a component of the path is actually a PHP script, and everything following it is part of the URI, such as:
http://www.example.com/some_dir/login.php/auth/8f631b92/
By choosing a different number for the last component of the URL, browsers can be tricked into thinking that they are dealing with a completely different website, and thus prompting the user for credentials again.
Note that using a random, unrestricted number will still allow the user to hit the back button to get back into the page. You should keep track of this number in a server-side file or database and regenerate it upon each successful login, so that the last number(s) become invalid. Using an invalid number might result in a 403 response or, depending on how you feel that day, a 302 to a nasty website.
Care should be taken when linking from the page generated in this case, since relative links will be relative to the virtual and non-existant directory rather than the true script directory.
Hope this helps somebody.
[#59] me at lalit dot org [2005-06-30 08:27:39]
A very simple HTTP Authentication script that solves the logout problem. I wasted a lot of time figuring out a way to logout. This one works perfectly fine.
<?php
function auth_user() {
$realm = mt_rand( 1, 1000000000 );
header('WWW-Authenticate: Basic realm="Realm ID='.$realm.']"');
header('HTTP/1.0 401 Unauthorized');
die("Unauthorized access forbidden!");
}
if (!isset($_SERVER['PHP_AUTH_USER'])) {
auth_user();
} else if (!isset($_SERVER['PHP_AUTH_USER'])) {
auth_user();
} else if ($_SERVER['PHP_AUTH_USER'] != $auser || $_SERVER['PHP_AUTH_PW'] != $apass) {
auth_user();
} else if (isset($_GET['action']) && $_GET['action'] == "logout") {
auth_user();
}
// Normal Page Code Here
?>
Hope this helps,
Lalit
[#60] snagnever at gmail dot com [2005-06-18 15:39:58]
It forces a auth each time the page is accessed:
(maybe can save someone)
<?php
header("Expires: Sat, 01 Jan 2000 00:00:00 GMT");
header("Last-Modified: ".gmdate("D, d M Y H:i:s")." GMT");
header("Cache-Control: post-check=0, pre-check=0",false);
header("Pragma: no-cache");
session_cache_limiter("public, no-store");
session_start();
function http_auth()
{
$_SESSION['AUTH'] = 1;
header('HTTP/1.0 401 Unauthorized');
header('WWW-Authenticate: Basic realm="sn4g auth system"');
// The actions to be done when the user clicks on 'cancel'
exit();
}
if( !isset($_SERVER['PHP_AUTH_USER']) or @$_SESSION['AUTH'] != 1 )
{
http_auth();
exit();
}
// Actions do be done when the user has logged
// rest, must clean the session array
$_SESSION = array();
session_destroy();
?>
[#61] aplanefan at mail dot com [2005-05-25 18:36:15]
I found a way to log out easily
<?php
ob_start();
if (!isset($_SERVER['PHP_AUTH_USER']) || $_COOKIE['isin'] != "1") {
header('WWW-Authenticate: Basic realm="My Realm"');
header('HTTP/1.0 401 Unauthorized');
setcookie ("isin", "1");
die('<a href="orderhan.php">Login</a>');
}
else {
if($_SERVER['PHP_AUTH_USER'] == "USER" && $_SERVER['PHP_AUTH_PW']== "PASSWORD") {
echo "you got in";
echo "<a href='".$_SEVER['PHP_SELF']."?action=logout'>logout</a>";
}
else {
setcookie ("isin", "", time() - 3600);
$url=$_SERVER['PHP_SELF'];
header("location: $url");
}
if($_GET['action'] == "logout") {
setcookie ("isin", "", time() - 3600);
$url=$_SERVER['PHP_SELF'];
header("location: $url");
}
}
ob_end_flush();
?>
[#62] charly at towebs dot com [2005-04-29 10:13:44]
A simpler approach on the post of:
bernard dot paques at bigfoot dot com
24-Sep-2004 01:42
This is another "patch" to the PHP_AUTH_USER and PHP_AUTH_PW server variables problem running PHP as a CGI.
First of all don't forget this fragment of code in your .htaccess (it's the only thing you need to make it work with mod_rewrite):
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization},L]
</IfModule>
Then login.php
<?php
$a = base64_decode( substr($_SERVER["REMOTE_USER"],6)) ;
if ( (strlen($a) == 0) || ( strcasecmp($a, ":" ) == 0 ))
{
header( 'WWW-Authenticate: Basic realm="Private"' );
header( 'HTTP/1.0 401 Unauthorized' );
}
else
{
list($name, $password) = explode(':', $a);
$_SERVER['PHP_AUTH_USER'] = $name;
$_SERVER['PHP_AUTH_PW'] = $password;
}
echo 'PHP_AUTH_USER =' . $_SERVER['PHP_AUTH_USER'] . '<br>';
echo 'PHP_AUTH_PW =' . $_SERVER['PHP_AUTH_PW'] . '<br>';
echo 'REMOTE_USER =' . $_SERVER['REMOTE_USER'] . '<br>';
?>
First, we decode the base64 encoded string discarding the first 6 characters of "Basic " and then we do a regular validation.
At the end of the script we print the variables to verify it's working. This should be ommited in the production version.
It's a variation of the script by Bernard Paques.
Thanks to him for that snippet.
[#63] sl at netcentrex dot net [2005-03-24 14:16:53]
This forces an instant re-authentication:
// Force a logout.
function imt_logout()
{
global $_SESSION;
global $HTTP_SERVER_VARS;
global $PHP_SELF;
// We mark the session as requiring a re-auth
$_SESSION['reauth-in-progress'] = 1;
// This forces the authentication cache clearing
header("WWW-Authenticate: Basic realm=\"My Realm\"");
header("HTTP/1.0 401 Unauthorized");
// In case of the user clicks "cancel" in the dialog box
print '<a href="http://'.$HTTP_SERVER_VARS['HTTP_HOST'].$PHP_SELF.'">click me</a>';
exit();
}
// Check login
function imt_login()
{
global $_SERVER;
global $_SESSION;
global $REGISTERED_USERS;
// the valid_user checks the user/password (very primitive test in this example)
if (!valid_user($_SERVER['PHP_AUTH_USER'], $REGISTERED_USERS))
{
session_destroy();
header("WWW-Authenticate: Basic realm=\"My Realm\"");
header("HTTP/1.0 401 Unauthorized");
exit();
}
// OK, the user is authenticated
$_SESSION['user'] = $_SERVER['PHP_AUTH_USER'];
}
Assuming that your page.php?action=logout forces a reauth on the same page, start your page with:
session_start()
if ($_REQUEST["action"] == "logout")
{
if (isset($_SESSION['reauth-in-progress']))
{
session_destroy();
header("Location: http://".$HTTP_SERVER_VARS['HTTP_HOST'].$PHP_SELF);
}
else
imt_logout();
}
imt_login();
[#64] brian at nerdlife dot net [2005-03-19 19:30:29]
My solution to the logout conondrum:
<?php
if($_GET[op] == 'logout')
{
header('WWW-Authenticate: Basic realm="Click \'Ok\' then \'Cancel\' to Log Out"');
header('HTTP/1.0 401 Unauthorized');
echo 'You have been successfully logged out. Click <a href="index.php">here</a> to log back in.');
die();
}
if(!isset($_SERVER[PHP_AUTH_USER]))
{
header('WWW-Authenticate: Basic realm="Site Login"');
header('HTTP/1.0 401 Unauthorized');
echo 'You must enter a valid username and password to access this resource.';
die();
}
else
{
//Validate User
//If Validated:
echo "Welcome. <a href='index.php?op=logout'>Logout?</a>"
}
?>
I assume that if the user is reliable enough to even bother logging out, they are reliable enough to click "ok" then "cancel", thereby logging out and displaying the "logged out" message.
[#65] jason [2004-08-14 22:12:34]
on the php+mysql auth code by tigran at freenet dot am
There are some security weaknesses.
First
$user
and
$pass
are both insecure, they could leave this code open to SQL injection, you should always remove invalid characters in both, or at least encode them.
Actually storing passwords as MD5 hashes leaves you less work to secure.
Second security risks
The same mysql user has rights to both update and select, and possibly even insert and on your auth database no less.
Again the SQL inject attack may occur with this., and the end user could then change the users username, password, or anything else in relation to this.
Third items is more of a performance issue,
Do you really need to update the database, as updates are slower then selects, and if you do them every time they access the page, you are costing some speed penalty.
One option, if you want to use sql (I think mysql has it) is memory only databases, and create a table within memory, the stores a unique session identifier for each user, that is logged in, or alternatively if it's a single front end system, you could use db files.
[#66] php at cscott dot net [2004-08-12 16:18:35]
Note that Microsoft has released a 'security update' which disables the use of username:password@host in http urls.
http://support.microsoft.com/default.aspx?scid=kb;en-us;834489
The methods described above which rely on this will no longer work in Microsoft browsers, sadly.
You can re-enable this functionality as described at
http://weblogs.asp.net/cumpsd/archive/2004/02/07/69366.aspx
but your users will probably be unwilling to do this.
[#67] chris at schaake dot nu [2004-06-17 09:42:26]
A simple script for SSL Client Certificate authentication with a basic authentication fall-back. I use this on my site using LDAP server to check username/passwords and client certificate to user mapping.
<?php
// Check if and how we are authenticated
if ($_SERVER['SSL_CLIENT_VERIFY'] != "SUCCESS") { // Not using a client certificate
if ((!$_SERVER['PHP_AUTH_USER']) && (!$_SERVER['PHP_AUTH_PW'])) { // Not logged in using basic authentication
authenticate(); // Send basic authentication headers
}
}
if ($_SERVER['SSL_CLIENT_S_DN_CN'] != "chris") { // Check CN name of cert
if (!(($_SERVER['PHP_AUTH_USER'] == "test") && ($_SERVER['PHP_AUTH_PW'] == "123"))) { // Check username and password
authenticate(); // Send basic authentication headers because username and/or password didnot match
}
}
phpinfo();
// Call authentication display
function authenticate() {
Header("WWW-Authenticate: Basic realm=Website");
Header("HTTP/1.0 401 Unauthorized");
error401();
exit;
}
?>
See my website (http://www.schaake.nu/index.php?page=/manuals/sslmanual.xml) for more details on client certificate with Apache and PHP.
[#68] nuno at mail dot ideianet dot pt [2004-05-13 15:33:40]
In Windows 2003 Server/IIS6 with the php4+ cgi I only get HTTP authentication working with:
<?php header("Status: 401 Access Denied"); ?>
with
<?php header('HTTP/1.0 401 Unauthorized'); ?>
doesn't work !
I also need in "Custom Errors" to select the range of "401;1" through "401;5" and click the "Set to Default" button.
Thanks rob at theblip dot com
[#69] steuber at aego dot de [2004-05-07 04:15:27]
Quite a good solution for the logout problem:
Just tell browser that it is successfully logged in!
This works as follows:
1. User clicks logout button
2. Script sends 401 Header
3. User does NOT enter a password
4. If no password is entered, script sends 200 Header
So the browser remembers no password as a valid password.
Example:
<?php
if (
(!isset($_SERVER['PHP_AUTH_USER']))
||(
($_GET["login"]=="login")
&& !(
($_SERVER['PHP_AUTH_USER']=="validuser")
&& ($_SERVER['PHP_AUTH_PW']=="validpass")
)
)
||(
($_GET["logout"]=="logout")
&& !($_SERVER['PHP_AUTH_PW']=="")
)
) {
Header("WWW-Authenticate: Basic realm=\"Realm\"");
Header("HTTP/1.0 401 Unauthorized");
echo "Not logged out...<br>\n";
echo "<a href=\"index.php?login=login\">Login</a>";
exit;
} else if ($_SERVER['PHP_AUTH_PW']=="") {
echo "Logged out...<br>\n";
echo "<a href=\"index.php?login=login\">Login</a>";
exit;
}
?>
[#70] najprogramato at post dot sk [2004-04-27 05:08:50]
Don't use apache authentification in plain text. Is more better to use own script to generete new ID which is relevant to password. Apache auth data are sent to every page, so the posible mistake are known.
[#71] ian AT iyates DOT co DOR uk [2004-03-05 05:32:01]
In my use of HTTP Authentication, I've found that some Apache setups swap around the usual variables.
Here's the fix I made so that you can still use PHP_AUTH_USER and PHP_AUTH_PW. Hope it helps someone
<?php
## Apache server fix ##
if (isset($_SERVER['PHP_AUTH_USER']) && !isset($_ENV['REMOTE_USER']))
$_ENV['REMOTE_USER'] = $_SERVER['PHP_AUTH_USER'];
if (isset($_SERVER['AUTH_PASSWORD']) && !isset($_ENV['PHP_AUTH_PW']))
$_ENV['PHP_AUTH_PW'] = $_SERVER['AUTH_PASSWORD'];
?>
[#72] rob at theblip dot com [2004-03-03 20:47:25]
Regarding HTTP authentication in IIS with the php cgi 4.3.4, there's one more step. I searched mightily and didn't find this information anywhere else, so here goes. When using HTTP auth with the php CGI, you need to do the following things:
1. In your php.ini file, set "cgi.rfc2616_headers = 0"
2. In Web Site Properties -> File/Directory Security -> Anonymous Access dialog box, check the "Anonymous access" checkbox and uncheck any other checkboxes (i.e. uncheck "Basic authentication," "Integrated Windows authentication," and "Digest" if it's enabled.) Click OK.
3. In "Custom Errors", select the range of "401;1" through "401;5" and click the "Set to Default" button.
It's this last step that is crucial, yet not documented anywhere. If you don't, instead of the headers asking for credentials, IIS will return its own fancy but useless 'you are not authenticated' page. But if you do, then the browser will properly ask for credentials, and supply them in the $_SERVER['PHP_AUTH_*'] elements.
[#73] ken_php_net at wolfpackinteractive dot com [2003-12-25 13:16:35]
Say you have password and groups files in standard Apache format (htpasswd etc.), but you want to apply authorization based on something other than filename, ie something you can't catch in .htaccess. You want to emulate the server behavior in PHP -- the equivalent of:
AuthType Basic
AuthName "Members"
AuthUserFile /path/to/.htpasswd
AuthGroupFile /path/to/.groups
require group Members
Here's what I came up with:
<?PHP
$AuthUserFile = file("/path/to/.htpasswd");
$AuthGroupFile = file("/path/to/.groups");
$group = "Members";
$realm = "Members";
function authenticate(){
header("WWW-Authenticate: Basic realm=\"$realm\"");
header('HTTP/1.0 401 Unauthorized');
echo "You must enter a valid user name and password to access the requested resource.";
exit;
}
for(; 1; authenticate()){
if (!isset($HTTP_SERVER_VARS['PHP_AUTH_USER']))
continue;
$user = $HTTP_SERVER_VARS['PHP_AUTH_USER'];
if(!preg_grep("/$group: $user$/", $AuthGroupFile)) # (format assumptions)
continue;
if(!($authUserLine = array_shift(preg_grep("/$user:.*$/", $AuthUserFile))))
continue;
preg_match("/$user:((..).*)$/", $authUserLine, $matches);
$authPW = $matches[1];
$salt = $matches[2];
$submittedPW = crypt($HTTP_SERVER_VARS['PHP_AUTH_PW'], $salt);
if($submittedPW != $authPW)
continue;
break;
}
echo "You got in!"
?>
[#74] Paul [2003-11-08 15:53:58]
Here is a extremely easy way to successfully logout.
<?php
if ( $realm == '' )
$realm = mt_rand( 1, 1000000000 );
header( 'WWW-Authenticate: Basic realm='.$realm );
?>
To log the user out simply change the value of $realm
[#75] ad_ver at inbox dot ru [2003-09-04 07:54:45]
Modified script from "jonhaynes at bigfoot dot com" using Oracle logon
<?php
function authenticate() {
header("WWW-Authenticate: Basic realm=\"My Realm\"");
header("HTTP/1.0 401 Unauthorized");
print("You must enter a valid login username and password
to access this resource.\n");
exit;
}
if(!isset($_SERVER['PHP_AUTH_USER'])){ authenticate(); }
else {
$conn = @ OCILogon($_SERVER['PHP_AUTH_USER'], $_SERVER['PHP_AUTH_PW'], "orcl92") ;
if(!$conn)
{ authenticate(); }
else {OCILogoff($conn);};
}
?>
[#76] steve at topozone dot com [2003-06-16 12:51:26]
The method described in the text does not appear to work with PHP in cgi mode and Apache-2.x. I seems that Apache has gotten stricter or introduced a bug such that you can initiate the authentication, but Apache seems to try to authenticate the browser response which always fails because it does not know what to authenticate against and the headers never get passed back to the PHP script.
I didn't try it with PHP as a module.
[#77] JKi [2003-02-14 03:38:19]
To clear HTTP authentication cache in Internet Explorer (6 SP1 and later), use "ClearAuthenticationCache" command.
document.execCommand("ClearAuthenticationCache");
[#78] emmanuel dot keller at net2000 dot ch [2003-01-14 14:14:08]
Some servers won't support the HTTP1.0 specification and will give an error 500 (for instance). This happened with a server where I uploaded an authentication script.
If it happens, you can try the HTTP1.1 header syntax :
<?php
header("WWW-Authenticate: Basic realm=\"My Realm\"");
header('status: 401 Unauthorized');
?>
[#79] yaroukh at email dot cz [2003-01-12 04:42:20]
Here is my solution - works in MSIE and Mozilla.
I use http-authentication only for the first time user accesses his
private page; after valid username and password are provided, he is
recognized using his sessionID and ip ...
the reasons are following:
1) when users changes his password it is not required instantly
(I find this quite comfortable)
2) auto-login function works fine (unless user click logout)
And here's how i works ...
The "trick" is to pass a temporary username+password to the browser.
(I call it "temporary" because no user account matching these
parameters is neccessary.)
The most essential thing is the following link on user's private page:
===
<?php $url = "http://".
$username. // see note 1
":".
Session_ID(). // see note 2
"@localhost/".PROJECT_NAME."/logout.phtml";
?>
<a href="
<?php=$url?>
">logout</a>
===
1) we pass the actual username because MSIE uses this username as
a "default pre-fill" for the login-window and some hash-string
would confuse the users.
2) the temporary password is not too important, but there are
two things we expect from it:
a) we need to know this string in the logout.phtml script
b) the string definetely should not match the user's password
(otherwise user gets logged back instantly); using current
Session_ID() we are pretty sure this won't happen
This link causes that the temporary login-params are available in
the logout.phtml script.
Using "www-authenticate" header in the logout.phtml script we force
the browser to accept our temporary login-params. (I suppose browser
actually repeats the request and the next time it checks
the login-params sent in the URL; but this is only my guess and
it is not important.)
The logout.phtml code:
===
<?php $query = "UPDATE users SET sessionID = NULL ".
"WHERE sessionID = '".Session_ID()."'";
$mysql->query($query);
// because we (me :o) use the sessionID and the ip for
// the identification we need to clean the sessionID; (I found it
// a little bit easier to destroy the sessionID in the db than
// unsetting the cookie and/or destroying+restarting
// the current session)
if($PHP_AUTH_PW != Session_ID()) {
// keep asking for the login-params untill PHP_AUTH_PW returned
// by the browser matches the current Session_ID() (which means
// that the browser accepted the temporary login-params
// we sent to it AND FORGOT THE REAL ONES)
Header("HTTP/1.0 401 Unauthorized");
Header("WWW-Authenticate: Basic realm=\"".PROJECT_NAME."\"");
}
?>
<html>
<head>
<meta http-equiv="author" content="yaroukh at email dot cz">
<title>
<?php=PROJECT_NAME?>
</title>
<link rel="stylesheet" href="style.css" type="text/css">
</head>
<body>
<a href="http://localhost/<?=PROJECT_NAME?>/main.phtml">continue</a>
</body>
</html>
===
About the "continue" link: the link is not too important, but using it
we can get rid off the temporary login-params which wouldn't look
too aesthetically in the address-bar. :o)
[#80] [2002-06-05 02:08:01]
A more elegant way to force a new name/password, cf. example 17-2 (if you don't mind passing the old user in the query string):
<?php
if (isset($PHP_AUTH_USER))
{
if (!isset($prev_user))
{
header("Location: http://$HTTP_HOST$PHP_SELF?prev_user=$PHP_AUTH_USER");
exit;
}
else
{
if ($PHP_AUTH_USER == $prev_user)
{
header('WWW-Authenticate: Basic realm="Secure"');
header('HTTP/1.0 401 Unauthorized');
exit;
}
}
}
else
{
header('WWW-Authenticate: Basic realm="Secure"');
header('HTTP/1.0 401 Unauthorized');
exit;
}
?>
The final set of headers is necessary because some browsers seem to unset $PHP_AUTH_USER when the location header is sent.
[#81] louis dot carlier at ngroups dot com [2002-05-23 20:22:06]
The definitive HTTP authorization code:
<?php
function login_error()
{
echo "error - login process failed."
}
if (!isset($PHP_AUTH_USER))
{
header("WWW-Authenticate: Basic realm=\"Mosaic Authorization process\"");
header("HTTP/1.0 401 Unauthorized");
//Result if user hits cancel button
login_error();
}
else
{
//check the login and password
if('=>test on login and password<=')
{
//User is logged
...
...
}
else
{
//This re-asks three times the login and password.
header( "WWW-Authenticate: Basic realm=\"Test Authentication System\"");
header("HTTP/1.0 401 Unauthorized");
//Result if user does not give good login and pass
login_error();
}
}
?>
[#82] sjeffrey at inquesis dot com [2002-01-29 15:00:50]
To get it to work with IIS try using this code before setting your "$auth = 0" and the "if (isset($PHP_AUTH_USER) && isset($PHP_AUTH_PW))"
<?php
//////////////////////////////////////////
if ($PHP_AUTH_USER == "" && $PHP_AUTH_PW == "" && ereg("^Basic ", $HTTP_AUTHORIZATION))
{
list($PHP_AUTH_USER, $PHP_AUTH_PW) =
explode(":", base64_decode(substr($HTTP_AUTHORIZATION, 6)));
}
//////////////////////////////////////////
?>
It worked for me on IIS 5 and PHP 4 in ISAPI
[#83] owld at mail dot ru [2000-08-30 15:04:34]
Good day.I've solved a problem where IE4 asks for the age one more time after a 401, defeating sending a 401 once to force a user to log on again.
<?php
function authenticate() {
setcookie("noauth","");
Header( "WWW-authenticate: Basic realm=\"test\"");
Header( "HTTP/1.0 401 Unauthorized");
echo "You must enter user name";
exit ;
}
if ( !isset($PHP_AUTH_USER) || ($logoff==1) && $noauth=="yes" ) {
authenticate();
}
?>
And logoff link -
<a href="samehtml.phtml?logoff=1">Logoff</a></td>
Dmitry Alyekhin