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; 1999-2006 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 $PHP_SELF in session and returns false. POST information is saved in
  25  * 'session_expired_post' variable, PHP_SELF 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         sqGetGlobalVar('PHP_SELF', $PHP_SELF, SQ_SERVER);
  40
  41         $session_expired_post = $_POST;
  42         $session_expired_location = $PHP_SELF;
  43         if (!sqsession_is_registered('session_expired_post')) {
  44             sqsession_register($session_expired_post,'session_expired_post');
  45         }
  46         if (!sqsession_is_registered('session_expired_location')) {
  47             sqsession_register($session_expired_location,'session_expired_location');
  48         }
  49         session_write_close();
  50
  51         return false;
  52 }
  53
  54 /**
  55  * Reads and decodes stored user password information
  56  *
  57  * Direct access to password information is deprecated.
  58  * @return string password in plain text
  59  * @since 1.5.1
  60  */
  61 function sqauth_read_password() {
  62     sqgetGlobalVar('key',         $key,       SQ_COOKIE);
  63     sqgetGlobalVar('onetimepad',  $onetimepad,SQ_SESSION);
  64
  65     return OneTimePadDecrypt($key, $onetimepad);
  66 }
  67
  68 /**
  69  * Saves or updates user password information
  70  *
  71  * This function is used to update password information that SquirrelMail
  72  * stores during existing web session. It does not modify password stored
  73  * in authentication system used by IMAP server.
  74  *
  75  * Function must be called before any html output started. Direct access
  76  * to password information is deprecated. Saved password information is
  77  * available only to next executed SquirrelMail script. If your script needs
  78  * access to saved password after sqauth_save_password() call, use returned
  79  * OTP encrypted key.
  80  * @param string $pass password
  81  * @return string password encrypted with OTP. In case script wants to access
  82  *  password information before reloading page.
  83  * @since 1.5.1
  84  */
  85 function sqauth_save_password($pass) {
  86     sqgetGlobalVar('base_uri',    $base_uri,   SQ_SESSION);
  87
  88     $onetimepad = OneTimePadCreate(strlen($pass));
  89     sqsession_register($onetimepad,'onetimepad');
  90     $key = OneTimePadEncrypt($pass, $onetimepad);
  91     sqsetcookie('key', $key, false, $base_uri);
  92     return $key;
  93 }
  94
  95 /**
  96  * Given the challenge from the server, supply the response using cram-md5 (See
  97  * RFC 2195 for details)
  98  *
  99  * @param string $username User ID
 100  * @param string $password User password supplied by User
 101  * @param string $challenge The challenge supplied by the server
 102  * @return string The response to be sent to the IMAP server
 103  * @since 1.4.0
 104  */
 105 function cram_md5_response ($username,$password,$challenge) {
 106     $challenge=base64_decode($challenge);
 107     $hash=bin2hex(hmac_md5($challenge,$password));
 108     $response=base64_encode($username . " " . $hash) . "\r\n";
 109     return $response;
 110 }
 111
 112 /**
 113  * Return Digest-MD5 response.
 114  * Given the challenge from the server, calculate and return the
 115  * response-string for digest-md5 authentication.  (See RFC 2831 for more
 116  * details)
 117  *
 118  * @param string $username User ID
 119  * @param string $password User password supplied by User
 120  * @param string $challenge The challenge supplied by the server
 121  * @param string $service The service name, usually 'imap'; it is used to
 122  *   define the digest-uri.
 123  * @param string $host The host name, usually the server's FQDN; it is used to
 124  *   define the digest-uri.
 125  * @param string $authz Authorization ID (since 1.5.2)
 126  * @return string The response to be sent to the IMAP server
 127  * @since 1.4.0
 128  */
 129 function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') {
 130     $result=digest_md5_parse_challenge($challenge);
 131
 132     // verify server supports qop=auth
 133     // $qop = explode(",",$result['qop']);
 134     //if (!in_array("auth",$qop)) {
 135     // rfc2831: client MUST fail if no qop methods supported
 136     // return false;
 137     //}
 138     $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
 139     $ncount = "00000001";
 140
 141     /* This can be auth (authentication only), auth-int (integrity protection), or
 142        auth-conf (confidentiality protection).  Right now only auth is supported.
 143        DO NOT CHANGE THIS VALUE */
 144     $qop_value = "auth";
 145
 146     $digest_uri_value = $service . '/' . $host;
 147
 148     // build the $response_value
 149     //FIXME This will probably break badly if a server sends more than one realm
 150     $string_a1 = utf8_encode($username).":";
 151     $string_a1 .= utf8_encode($result['realm']).":";
 152     $string_a1 .= utf8_encode($password);
 153     $string_a1 = hmac_md5($string_a1);
 154     $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
 155     $A1 = bin2hex(hmac_md5($A1));
 156     $A2 = "AUTHENTICATE:$digest_uri_value";
 157     // If qop is auth-int or auth-conf, A2 gets a little extra
 158     if ($qop_value != 'auth') {
 159         $A2 .= ':00000000000000000000000000000000';
 160     }
 161     $A2 = bin2hex(hmac_md5($A2));
 162
 163     $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
 164     $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
 165
 166     $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
 167     $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
 168     $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
 169     $reply .= ',qop=' . $qop_value;
 170     if(!empty($authz)) {
 171         $reply .= ',authzid=' . $authz;
 172     }
 173     $reply = base64_encode($reply);
 174     return $reply . "\r\n";
 175
 176 }
 177
 178 /**
 179  * Parse Digest-MD5 challenge.
 180  * This function parses the challenge sent during DIGEST-MD5 authentication and
 181  * returns an array. See the RFC for details on what's in the challenge string.
 182  *
 183  * @param string $challenge Digest-MD5 Challenge
 184  * @return array Digest-MD5 challenge decoded data
 185  * @since 1.4.0
 186  */
 187 function digest_md5_parse_challenge($challenge) {
 188     $challenge=base64_decode($challenge);
 189     while (isset($challenge)) {
 190         if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
 191             $challenge=substr($challenge,1);
 192         }
 193         $key=explode('=',$challenge,2);
 194         $challenge=$key[1];
 195         $key=$key[0];
 196         if ($challenge{0} == '"') {
 197             // We're in a quoted value
 198             // Drop the first quote, since we don't care about it
 199             $challenge=substr($challenge,1);
 200             // Now explode() to the next quote, which is the end of our value
 201             $val=explode('"',$challenge,2);
 202             $challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
 203             $value=explode(',',$val[0]);
 204             // Now, for those quoted values that are only 1 piece..
 205             if (sizeof($value) == 1) {
 206                 $value=$value[0];  // Convert to non-array
 207             }
 208         } else {
 209             // We're in a "simple" value - explode to next comma
 210             $val=explode(',',$challenge,2);
 211             if (isset($val[1])) {
 212                 $challenge=$val[1];
 213             } else {
 214                 unset($challenge);
 215             }
 216             $value=$val[0];
 217         }
 218         $parsed["$key"]=$value;
 219     } // End of while loop
 220     return $parsed;
 221 }
 222
 223 /**
 224  * Creates a HMAC digest that can be used for auth purposes
 225  * See RFCs 2104, 2617, 2831
 226  * Uses mhash() extension if available
 227  *
 228  * @param string $data Data to apply hash function to.
 229  * @param string $key Optional key, which, if supplied, will be used to
 230  * calculate data's HMAC.
 231  * @return string HMAC Digest string
 232  * @since 1.4.0
 233  */
 234 function hmac_md5($data, $key='') {
 235     if (extension_loaded('mhash')) {
 236         if ($key== '') {
 237             $mhash=mhash(MHASH_MD5,$data);
 238         } else {
 239             $mhash=mhash(MHASH_MD5,$data,$key);
 240         }
 241         return $mhash;
 242     }
 243     if (!$key) {
 244         return pack('H*',md5($data));
 245     }
 246     $key = str_pad($key,64,chr(0x00));
 247     if (strlen($key) > 64) {
 248         $key = pack("H*",md5($key));
 249     }
 250     $k_ipad =  $key ^ str_repeat(chr(0x36), 64) ;
 251     $k_opad =  $key ^ str_repeat(chr(0x5c), 64) ;
 252     /* Heh, let's get recursive. */
 253     $hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
 254     return $hmac;
 255 }
 256
 257 /**
 258  * Fillin user and password based on SMTP auth settings.
 259  *
 260  * @param string $user Reference to SMTP username
 261  * @param string $pass Reference to SMTP password (unencrypted)
 262  * @since 1.5.0
 263  */
 264 function get_smtp_user(&$user, &$pass) {
 265     global $username, $smtp_auth_mech,
 266            $smtp_sitewide_user, $smtp_sitewide_pass;
 267
 268     if ($smtp_auth_mech == 'none') {
 269         $user = '';
 270         $pass = '';
 271     } elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) &&
 272                !empty($smtp_sitewide_user)) {
 273         $user = $smtp_sitewide_user;
 274         $pass = $smtp_sitewide_pass;
 275     } else {
 276         $user = $username;
 277         $pass = sqauth_read_password();
 278     }
 279 }