+/**
+ * Detect whether user is logged in
+ *
+ * Function is similar to is_logged_in() function. If user is logged in, function
+ * returns true. If user is not logged in or session is expired, function saves $_POST
+ * and PAGE_NAME in session and returns false. POST information is saved in
+ * 'session_expired_post' variable, PAGE_NAME is saved in 'session_expired_location'.
+ *
+ * This function optionally checks the referrer of this page request. If the
+ * administrator wants to impose a check that the referrer of this page request
+ * is another page on the same domain (otherwise, the page request is likely
+ * the result of a XSS or phishing attack), then they need to specify the
+ * acceptable referrer domain in a variable named $check_referrer in
+ * config/config.php (or the configuration tool) for which the value is
+ * usually the same as the $domain setting (for example:
+ * $check_referrer = 'example.com';
+ * However, in some cases (where proxy servers are in use, etc.), the
+ * acceptable referrer might be different. If $check_referrer is set to
+ * "###DOMAIN###", then the current value of $domain is used (useful in
+ * situations where $domain might change at runtime (when using the Login
+ * Manager plugin to host multiple domains with one SquirrelMail installation,
+ * for example)):
+ * $check_referrer = '###DOMAIN###';
+ * NOTE HOWEVER, that referrer checks are not foolproof - they can be spoofed
+ * by browsers, and some browsers intentionally don't send them, in which
+ * case SquirrelMail silently ignores referrer checks.
+ *
+ * Script that uses this function instead of is_logged_in() function, must handle user
+ * level messages.
+ * @return boolean
+ * @since 1.5.1
+ */
+function sqauth_is_logged_in() {
+
+ global $check_referrer, $domain;
+ if (!sqgetGlobalVar('HTTP_REFERER', $referrer, SQ_SERVER)) $referrer = '';
+ if ($check_referrer == '###DOMAIN###') $check_referrer = $domain;
+ if (!empty($check_referrer)) {
+ $ssl_check_referrer = 'https://' . $check_referrer;
+ $plain_check_referrer = 'http://' . $check_referrer;
+ }
+ if (sqsession_is_registered('user_is_logged_in')
+ && (!$check_referrer || empty($referrer)
+ || ($check_referrer && !empty($referrer)
+ && (strpos(strtolower($referrer), strtolower($plain_check_referrer)) === 0
+ || strpos(strtolower($referrer), strtolower($ssl_check_referrer)) === 0)))) {
+ return true;
+ }
+
+ // First we store some information in the new session to prevent
+ // information-loss.
+ $session_expired_post = $_POST;
+ if (defined('PAGE_NAME'))
+ $session_expired_location = PAGE_NAME;
+ else
+ $session_expired_location = '';
+
+ if (!sqsession_is_registered('session_expired_post')) {
+ sqsession_register($session_expired_post,'session_expired_post');
+ }
+ if (!sqsession_is_registered('session_expired_location')) {
+ sqsession_register($session_expired_location,'session_expired_location');
+ }
+
+ session_write_close();
+
+ return false;
+}
+
+/**
+ * Reads and decodes stored user password information
+ *
+ * Direct access to password information is deprecated.
+ * @return string password in plain text
+ * @since 1.5.1
+ */
+function sqauth_read_password() {
+ global $currentHookName;
+ if ($currentHookName == 'login_verified') global $key;
+
+ sqgetGlobalVar('key', $key, SQ_COOKIE);
+ sqgetGlobalVar('onetimepad', $onetimepad,SQ_SESSION);
+
+ return OneTimePadDecrypt($key, $onetimepad);
+}
+
+/**
+ * Saves or updates user password information
+ *
+ * This function is used to update the password information that
+ * SquirrelMail stores in the existing PHP session. It does NOT
+ * modify the password stored in the authentication system used
+ * by the IMAP server.
+ *
+ * This function must be called before any html output is started.
+ * Direct access to password information is deprecated. The saved
+ * password information is available only to the SquirrelMail script
+ * that is called/executed AFTER the current one. If your script
+ * needs access to the saved password after a sqauth_save_password()
+ * call, use the returned OTP encrypted key.
+ *
+ * @param string $pass password
+ *
+ * @return string Password encrypted with OTP. In case the script
+ * wants to access the password information before
+ * the end of its execution.
+ *
+ * @since 1.5.1
+ *
+ */
+function sqauth_save_password($pass) {
+ sqgetGlobalVar('base_uri', $base_uri, SQ_SESSION);
+
+ $onetimepad = OneTimePadCreate(strlen($pass));
+ sqsession_register($onetimepad,'onetimepad');
+ $key = OneTimePadEncrypt($pass, $onetimepad);
+ sqsetcookie('key', $key, false, $base_uri);
+ return $key;
+}
+
+/**
+ * Given the challenge from the server, supply the response using cram-md5 (See
+ * RFC 2195 for details)
+ *
+ * @param string $username User ID
+ * @param string $password User password supplied by User
+ * @param string $challenge The challenge supplied by the server
+ * @return string The response to be sent to the IMAP server
+ * @since 1.4.0
+ */
+function cram_md5_response ($username,$password,$challenge) {
+ $challenge=base64_decode($challenge);
+ $hash=bin2hex(hmac_md5($challenge,$password));
+ $response=base64_encode($username . " " . $hash) . "\r\n";
+ return $response;
+}
+
+/**
+ * Return Digest-MD5 response.
+ * Given the challenge from the server, calculate and return the
+ * response-string for digest-md5 authentication. (See RFC 2831 for more
+ * details)
+ *
+ * @param string $username User ID
+ * @param string $password User password supplied by User
+ * @param string $challenge The challenge supplied by the server
+ * @param string $service The service name, usually 'imap'; it is used to
+ * define the digest-uri.
+ * @param string $host The host name, usually the server's FQDN; it is used to
+ * define the digest-uri.
+ * @param string $authz Authorization ID (since 1.5.2)
+ * @return string The response to be sent to the IMAP server
+ * @since 1.4.0
+ */
+function digest_md5_response ($username,$password,$challenge,$service,$host,$authz='') {
+ $result=digest_md5_parse_challenge($challenge);
+ //FIXME we should check that $result contains the expected values that we use below
+
+ // verify server supports qop=auth
+ // $qop = explode(",",$result['qop']);
+ //if (!in_array("auth",$qop)) {
+ // rfc2831: client MUST fail if no qop methods supported
+ // return false;
+ //}
+ $cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
+ $ncount = "00000001";
+
+ /* This can be auth (authentication only), auth-int (integrity protection), or
+ auth-conf (confidentiality protection). Right now only auth is supported.
+ DO NOT CHANGE THIS VALUE */
+ $qop_value = "auth";
+
+ $digest_uri_value = $service . '/' . $host;
+
+ // build the $response_value
+ //FIXME This will probably break badly if a server sends more than one realm
+ $string_a1 = utf8_encode($username).":";
+ $string_a1 .= utf8_encode($result['realm']).":";
+ $string_a1 .= utf8_encode($password);
+ $string_a1 = hmac_md5($string_a1);
+ $A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
+ if(!empty($authz)) {
+ $A1 .= ":" . utf8_encode($authz);
+ }
+ $A1 = bin2hex(hmac_md5($A1));
+ $A2 = "AUTHENTICATE:$digest_uri_value";
+ // If qop is auth-int or auth-conf, A2 gets a little extra
+ if ($qop_value != 'auth') {
+ $A2 .= ':00000000000000000000000000000000';
+ }
+ $A2 = bin2hex(hmac_md5($A2));
+
+ $string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
+ $response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
+
+ $reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
+ $reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
+ $reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
+ $reply .= ',qop=' . $qop_value;
+ if(!empty($authz)) {
+ $reply .= ',authzid=' . $authz;
+ }
+ $reply = base64_encode($reply);
+ return $reply . "\r\n";
+
+}
+
+/**
+ * Parse Digest-MD5 challenge.
+ * This function parses the challenge sent during DIGEST-MD5 authentication and
+ * returns an array. See the RFC for details on what's in the challenge string.
+ *
+ * @param string $challenge Digest-MD5 Challenge
+ * @return array Digest-MD5 challenge decoded data
+ * @since 1.4.0
+ */
+function digest_md5_parse_challenge($challenge) {
+ $challenge=base64_decode($challenge);
+ $parsed = array();
+ while (!empty($challenge)) {
+ if ($challenge[0] == ',') { // First char is a comma, must not be 1st time through loop
+ $challenge=substr($challenge,1);