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     if (defined('PAGE_NAME'))
  41         $session_expired_location = PAGE_NAME;
  42     else
  43         $session_expired_location = '';
  44
  45     if (!sqsession_is_registered('session_expired_post')) {
  46         sqsession_register($session_expired_post,'session_expired_post');
  47     }
  48     if (!sqsession_is_registered('session_expired_location')) {
  49         sqsession_register($session_expired_location,'session_expired_location');
  50     }
  51
  52     session_write_close();
  53
  54     return false;
  55 }
  56
  57 /**
  58  * Reads and decodes stored user password information
  59  *
  60  * Direct access to password information is deprecated.
  61  * @return string password in plain text
  62  * @since 1.5.1
  63  */
  64 function sqauth_read_password() {
  65     sqgetGlobalVar('key',         $key,       SQ_COOKIE);
  66     sqgetGlobalVar('onetimepad',  $onetimepad,SQ_SESSION);
  67
  68     return OneTimePadDecrypt($key, $onetimepad);
  69 }
  70
  71 /**
  72  * Saves or updates user password information
  73  *
  74  * This function is used to update password information that SquirrelMail
  75  * stores during existing web session. It does not modify password stored
  76  * in authentication system used by IMAP server.
  77  *
  78  * Function must be called before any html output started. Direct access
  79  * to password information is deprecated. Saved password information is
  80  * available only to next executed SquirrelMail script. If your script needs
  81  * access to saved password after sqauth_save_password() call, use returned
  82  * OTP encrypted key.
  83  * @param string $pass password
  84  * @return string password encrypted with OTP. In case script wants to access
  85  *  password information before reloading page.
  86  * @since 1.5.1
  87  */
  88 function sqauth_save_password($pass) {
  89     sqgetGlobalVar('base_uri',    $base_uri,   SQ_SESSION);
  90
  91     $onetimepad = OneTimePadCreate(strlen($pass));
  92     sqsession_register($onetimepad,'onetimepad');
  93     $key = OneTimePadEncrypt($pass, $onetimepad);
  94     sqsetcookie('key', $key, false, $base_uri);
  95     return $key;
  96 }
  97
  98 /**
  99  * Given the challenge from the server, supply the response using cram-md5 (See
 100  * RFC 2195 for details)
 101  *
 102  * @param string $username User ID
 103  * @param string $password User password supplied by User
 104  * @param string $challenge The challenge supplied by the server
 105  * @return string The response to be sent to the IMAP server
 106  * @since 1.4.0
 107  */
 108 function cram_md5_response ($username,$password,$challenge) {
 109     $challenge=base64_decode($challenge);
 110     $hash=bin2hex(hmac_md5($challenge,$password));
 111     $response=base64_encode($username . " " . $hash) . "\r\n";
 112     return $response;
 113 }
 114
 115 /**
 116  * Return Digest-MD5 response.
 117  * Given the challenge from the server, calculate and return the
 118  * response-string for digest-md5 authentication.  (See RFC 2831 for more
 119  * details)
 120  *
 121  * @param string $username User ID
 122  * @param string $password User password supplied by User
 123  * @param string $challenge The challenge supplied by the server
 124  * @param string $service The service name, usually 'imap'; it is used to
 125  *   define the digest-uri.
 126  * @param string $host The host name, usually the server's FQDN; it is used to
 127  *   define the digest-uri.
 128  * @param string $authz Authorization ID (since 1.5.2)
 129  * @return string The response to be sent to the IMAP server
 130  * @since 1.4.0
 131  */
 132 function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') {
 133     $result=digest_md5_parse_challenge($challenge);
 134
 135     // verify server supports qop=auth
 136     // $qop = explode(",",$result['qop']);
 137     //if (!in_array("auth",$qop)) {
 138     // rfc2831: client MUST fail if no qop methods supported
 139     // return false;
 140     //}
 141     $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
 142     $ncount = "00000001";
 143
 144     /* This can be auth (authentication only), auth-int (integrity protection), or
 145        auth-conf (confidentiality protection).  Right now only auth is supported.
 146        DO NOT CHANGE THIS VALUE */
 147     $qop_value = "auth";
 148
 149     $digest_uri_value = $service . '/' . $host;
 150
 151     // build the $response_value
 152     //FIXME This will probably break badly if a server sends more than one realm
 153     $string_a1 = utf8_encode($username).":";
 154     $string_a1 .= utf8_encode($result['realm']).":";
 155     $string_a1 .= utf8_encode($password);
 156     $string_a1 = hmac_md5($string_a1);
 157     $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
 158     if(!empty($authz)) {
 159         $A1 .= ":" . utf8_encode($authz);
 160     }
 161     $A1 = bin2hex(hmac_md5($A1));
 162     $A2 = "AUTHENTICATE:$digest_uri_value";
 163     // If qop is auth-int or auth-conf, A2 gets a little extra
 164     if ($qop_value != 'auth') {
 165         $A2 .= ':00000000000000000000000000000000';
 166     }
 167     $A2 = bin2hex(hmac_md5($A2));
 168
 169     $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
 170     $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
 171
 172     $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
 173     $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
 174     $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
 175     $reply .= ',qop=' . $qop_value;
 176     if(!empty($authz)) {
 177         $reply .= ',authzid=' . $authz;
 178     }
 179     $reply = base64_encode($reply);
 180     return $reply . "\r\n";
 181
 182 }
 183
 184 /**
 185  * Parse Digest-MD5 challenge.
 186  * This function parses the challenge sent during DIGEST-MD5 authentication and
 187  * returns an array. See the RFC for details on what's in the challenge string.
 188  *
 189  * @param string $challenge Digest-MD5 Challenge
 190  * @return array Digest-MD5 challenge decoded data
 191  * @since 1.4.0
 192  */
 193 function digest_md5_parse_challenge($challenge) {
 194     $challenge=base64_decode($challenge);
 195     while (isset($challenge)) {
 196         if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
 197             $challenge=substr($challenge,1);
 198         }
 199         $key=explode('=',$challenge,2);
 200         $challenge=$key[1];
 201         $key=$key[0];
 202         if ($challenge{0} == '"') {
 203             // We're in a quoted value
 204             // Drop the first quote, since we don't care about it
 205             $challenge=substr($challenge,1);
 206             // Now explode() to the next quote, which is the end of our value
 207             $val=explode('"',$challenge,2);
 208             $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
 209             $value=explode(',',$val[0]);
 210             // Now, for those quoted values that are only 1 piece..
 211             if (sizeof($value) == 1) {
 212                 $value=$value[0];  // Convert to non-array
 213             }
 214         } else {
 215             // We're in a "simple" value - explode to next comma
 216             $val=explode(',',$challenge,2);
 217             if (isset($val[1])) {
 218                 $challenge=$val[1];
 219             } else {
 220                 unset($challenge);
 221             }
 222             $value=$val[0];
 223         }
 224         $parsed["$key"]=$value;
 225     } // End of while loop
 226     return $parsed;
 227 }
 228
 229 /**
 230  * Creates a HMAC digest that can be used for auth purposes
 231  * See RFCs 2104, 2617, 2831
 232  * Uses mhash() extension if available
 233  *
 234  * @param string $data Data to apply hash function to.
 235  * @param string $key Optional key, which, if supplied, will be used to
 236  * calculate data's HMAC.
 237  * @return string HMAC Digest string
 238  * @since 1.4.0
 239  */
 240 function hmac_md5($data, $key='') {
 241     if (extension_loaded('mhash')) {
 242         if ($key== '') {
 243             $mhash=mhash(MHASH_MD5,$data);
 244         } else {
 245             $mhash=mhash(MHASH_MD5,$data,$key);
 246         }
 247         return $mhash;
 248     }
 249     if (!$key) {
 250         return pack('H*',md5($data));
 251     }
 252     $key = str_pad($key,64,chr(0x00));
 253     if (strlen($key) > 64) {
 254         $key = pack("H*",md5($key));
 255     }
 256     $k_ipad =  $key ^ str_repeat(chr(0x36), 64) ;
 257     $k_opad =  $key ^ str_repeat(chr(0x5c), 64) ;
 258     /* Heh, let's get recursive. */
 259     $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
 260     return $hmac;
 261 }
 262
 263 /**
 264  * Fillin user and password based on SMTP auth settings.
 265  *
 266  * @param string $user Reference to SMTP username
 267  * @param string $pass Reference to SMTP password (unencrypted)
 268  * @since 1.4.11
 269  */
 270 function get_smtp_user(&$user, &$pass) {
 271     global $username, $smtp_auth_mech,
 272            $smtp_sitewide_user, $smtp_sitewide_pass;
 273
 274     if ($smtp_auth_mech == 'none') {
 275         $user = '';
 276         $pass = '';
 277     } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) &&
 278                !empty($smtp_sitewide_user)) {
 279         $user = $smtp_sitewide_user;
 280         $pass = $smtp_sitewide_pass;
 281     } else {
 282         $user = $username;
 283         $pass = sqauth_read_password();
 284     }
 285
 286     // plugin authors note: override $user or $pass by
 287     // directly changing the arguments array contents
 288     // in your plugin e.g., $args[0] = 'new_username';
 289     //
 290     $temp = array(&$user, &$pass);
 291     do_hook('smtp_auth', $temp);
 292 }