functions/auth.php

   1 <?php
   2
   3 /**
   4  * auth.php
   5  *
   6  * Contains functions used to do authentication.
   7  *
   8  * Dependencies:
   9  *  functions/global.php
  10  *  functions/strings.php.
  11  *
  12  * @copyright &copy; 1999-2007 The SquirrelMail Project Team
  13  * @license http://opensource.org/licenses/gpl-license.php GNU Public License
  14  * @version $Id$
  15  * @package squirrelmail
  16  */
  17
  18
  19 /**
  20  * Detect whether user is logged in
  21  *
  22  * Function is similar to is_logged_in() function. If user is logged in, function
  23  * returns true. If user is not logged in or session is expired, function saves $_POST
  24  * and PAGE_NAME in session and returns false. POST information is saved in
  25  * 'session_expired_post' variable, PAGE_NAME is saved in 'session_expired_location'.
  26  *
  27  * Script that uses this function instead of is_logged_in() function, must handle user
  28  * level messages.
  29  * @return boolean
  30  * @since 1.5.1
  31  */
  32 function sqauth_is_logged_in() {
  33     if ( sqsession_is_registered('user_is_logged_in') ) {
  34         return true;
  35     }
  36
  37         //  First we store some information in the new session to prevent
  38         //  information-loss.
  39         $session_expired_post = $_POST;
  40         $session_expired_location = PAGE_NAME;
  41         if (!sqsession_is_registered('session_expired_post')) {
  42             sqsession_register($session_expired_post,'session_expired_post');
  43         }
  44         if (!sqsession_is_registered('session_expired_location')) {
  45             sqsession_register($session_expired_location,'session_expired_location');
  46         }
  47         session_write_close();
  48
  49         return false;
  50 }
  51
  52 /**
  53  * Reads and decodes stored user password information
  54  *
  55  * Direct access to password information is deprecated.
  56  * @return string password in plain text
  57  * @since 1.5.1
  58  */
  59 function sqauth_read_password() {
  60     sqgetGlobalVar('key',         $key,       SQ_COOKIE);
  61     sqgetGlobalVar('onetimepad',  $onetimepad,SQ_SESSION);
  62
  63     return OneTimePadDecrypt($key, $onetimepad);
  64 }
  65
  66 /**
  67  * Saves or updates user password information
  68  *
  69  * This function is used to update password information that SquirrelMail
  70  * stores during existing web session. It does not modify password stored
  71  * in authentication system used by IMAP server.
  72  *
  73  * Function must be called before any html output started. Direct access
  74  * to password information is deprecated. Saved password information is
  75  * available only to next executed SquirrelMail script. If your script needs
  76  * access to saved password after sqauth_save_password() call, use returned
  77  * OTP encrypted key.
  78  * @param string $pass password
  79  * @return string password encrypted with OTP. In case script wants to access
  80  *  password information before reloading page.
  81  * @since 1.5.1
  82  */
  83 function sqauth_save_password($pass) {
  84     sqgetGlobalVar('base_uri',    $base_uri,   SQ_SESSION);
  85
  86     $onetimepad = OneTimePadCreate(strlen($pass));
  87     sqsession_register($onetimepad,'onetimepad');
  88     $key = OneTimePadEncrypt($pass, $onetimepad);
  89     sqsetcookie('key', $key, false, $base_uri);
  90     return $key;
  91 }
  92
  93 /**
  94  * Given the challenge from the server, supply the response using cram-md5 (See
  95  * RFC 2195 for details)
  96  *
  97  * @param string $username User ID
  98  * @param string $password User password supplied by User
  99  * @param string $challenge The challenge supplied by the server
 100  * @return string The response to be sent to the IMAP server
 101  * @since 1.4.0
 102  */
 103 function cram_md5_response ($username,$password,$challenge) {
 104     $challenge=base64_decode($challenge);
 105     $hash=bin2hex(hmac_md5($challenge,$password));
 106     $response=base64_encode($username . " " . $hash) . "\r\n";
 107     return $response;
 108 }
 109
 110 /**
 111  * Return Digest-MD5 response.
 112  * Given the challenge from the server, calculate and return the
 113  * response-string for digest-md5 authentication.  (See RFC 2831 for more
 114  * details)
 115  *
 116  * @param string $username User ID
 117  * @param string $password User password supplied by User
 118  * @param string $challenge The challenge supplied by the server
 119  * @param string $service The service name, usually 'imap'; it is used to
 120  *   define the digest-uri.
 121  * @param string $host The host name, usually the server's FQDN; it is used to
 122  *   define the digest-uri.
 123  * @param string $authz Authorization ID (since 1.5.2)
 124  * @return string The response to be sent to the IMAP server
 125  * @since 1.4.0
 126  */
 127 function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') {
 128     $result=digest_md5_parse_challenge($challenge);
 129
 130     // verify server supports qop=auth
 131     // $qop = explode(",",$result['qop']);
 132     //if (!in_array("auth",$qop)) {
 133     // rfc2831: client MUST fail if no qop methods supported
 134     // return false;
 135     //}
 136     $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
 137     $ncount = "00000001";
 138
 139     /* This can be auth (authentication only), auth-int (integrity protection), or
 140        auth-conf (confidentiality protection).  Right now only auth is supported.
 141        DO NOT CHANGE THIS VALUE */
 142     $qop_value = "auth";
 143
 144     $digest_uri_value = $service . '/' . $host;
 145
 146     // build the $response_value
 147     //FIXME This will probably break badly if a server sends more than one realm
 148     $string_a1 = utf8_encode($username).":";
 149     $string_a1 .= utf8_encode($result['realm']).":";
 150     $string_a1 .= utf8_encode($password);
 151     $string_a1 = hmac_md5($string_a1);
 152     $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
 153     if(!empty($authz)) {
 154         $A1 .= ":" . utf8_encode($authz);
 155     }
 156     $A1 = bin2hex(hmac_md5($A1));
 157     $A2 = "AUTHENTICATE:$digest_uri_value";
 158     // If qop is auth-int or auth-conf, A2 gets a little extra
 159     if ($qop_value != 'auth') {
 160         $A2 .= ':00000000000000000000000000000000';
 161     }
 162     $A2 = bin2hex(hmac_md5($A2));
 163
 164     $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
 165     $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
 166
 167     $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
 168     $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
 169     $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
 170     $reply .= ',qop=' . $qop_value;
 171     if(!empty($authz)) {
 172         $reply .= ',authzid=' . $authz;
 173     }
 174     $reply = base64_encode($reply);
 175     return $reply . "\r\n";
 176
 177 }
 178
 179 /**
 180  * Parse Digest-MD5 challenge.
 181  * This function parses the challenge sent during DIGEST-MD5 authentication and
 182  * returns an array. See the RFC for details on what's in the challenge string.
 183  *
 184  * @param string $challenge Digest-MD5 Challenge
 185  * @return array Digest-MD5 challenge decoded data
 186  * @since 1.4.0
 187  */
 188 function digest_md5_parse_challenge($challenge) {
 189     $challenge=base64_decode($challenge);
 190     while (isset($challenge)) {
 191         if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
 192             $challenge=substr($challenge,1);
 193         }
 194         $key=explode('=',$challenge,2);
 195         $challenge=$key[1];
 196         $key=$key[0];
 197         if ($challenge{0} == '"') {
 198             // We're in a quoted value
 199             // Drop the first quote, since we don't care about it
 200             $challenge=substr($challenge,1);
 201             // Now explode() to the next quote, which is the end of our value
 202             $val=explode('"',$challenge,2);
 203             $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
 204             $value=explode(',',$val[0]);
 205             // Now, for those quoted values that are only 1 piece..
 206             if (sizeof($value) == 1) {
 207                 $value=$value[0];  // Convert to non-array
 208             }
 209         } else {
 210             // We're in a "simple" value - explode to next comma
 211             $val=explode(',',$challenge,2);
 212             if (isset($val[1])) {
 213                 $challenge=$val[1];
 214             } else {
 215                 unset($challenge);
 216             }
 217             $value=$val[0];
 218         }
 219         $parsed["$key"]=$value;
 220     } // End of while loop
 221     return $parsed;
 222 }
 223
 224 /**
 225  * Creates a HMAC digest that can be used for auth purposes
 226  * See RFCs 2104, 2617, 2831
 227  * Uses mhash() extension if available
 228  *
 229  * @param string $data Data to apply hash function to.
 230  * @param string $key Optional key, which, if supplied, will be used to
 231  * calculate data's HMAC.
 232  * @return string HMAC Digest string
 233  * @since 1.4.0
 234  */
 235 function hmac_md5($data, $key='') {
 236     if (extension_loaded('mhash')) {
 237         if ($key== '') {
 238             $mhash=mhash(MHASH_MD5,$data);
 239         } else {
 240             $mhash=mhash(MHASH_MD5,$data,$key);
 241         }
 242         return $mhash;
 243     }
 244     if (!$key) {
 245         return pack('H*',md5($data));
 246     }
 247     $key = str_pad($key,64,chr(0x00));
 248     if (strlen($key) > 64) {
 249         $key = pack("H*",md5($key));
 250     }
 251     $k_ipad =  $key ^ str_repeat(chr(0x36), 64) ;
 252     $k_opad =  $key ^ str_repeat(chr(0x5c), 64) ;
 253     /* Heh, let's get recursive. */
 254     $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
 255     return $hmac;
 256 }
 257
 258 /**
 259  * Fillin user and password based on SMTP auth settings.
 260  *
 261  * @param string $user Reference to SMTP username
 262  * @param string $pass Reference to SMTP password (unencrypted)
 263  * @since 1.5.0
 264  */
 265 function get_smtp_user(&$user, &$pass) {
 266     global $username, $smtp_auth_mech,
 267            $smtp_sitewide_user, $smtp_sitewide_pass;
 268
 269     if ($smtp_auth_mech == 'none') {
 270         $user = '';
 271         $pass = '';
 272     } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) &&
 273                !empty($smtp_sitewide_user)) {
 274         $user = $smtp_sitewide_user;
 275         $pass = $smtp_sitewide_pass;
 276     } else {
 277         $user = $username;
 278         $pass = sqauth_read_password();
 279     }
 280
 281     // plugin authors note: override $user or $pass by
 282     // directly changing the arguments array contents
 283     // in your plugin e.g., $args[0] = 'new_username';
 284     //
 285     do_hook('smtp_auth', $temp=array(&$user, &$pass));
 286 }