From 811cdcdfcb0442791b0c6dfd8814c621a44731cc Mon Sep 17 00:00:00 2001
From: dew-git <55564947+dew-git@users.noreply.github.com>
Date: Thu, 10 Oct 2019 15:21:41 -0800
Subject: [PATCH 1/6] Fix security vulnerbilities.

Fix possible length extension attack, predicable generators, timing attacks on hash comparision and improved formatting.
---
 library/OAuth1.php               | 371 ++++++++++++++++++-------------
 mod/lostpass.php                 |   3 +-
 src/Core/Authentication.php      |  20 +-
 src/Model/Register.php           |   3 +-
 src/Model/User.php               |  92 +++++---
 src/Module/Login.php             |  32 ++-
 src/Network/FKOAuthDataStore.php |   8 +-
 src/Util/Strings.php             | 258 ++++++++++-----------
 8 files changed, 455 insertions(+), 332 deletions(-)

diff --git a/library/OAuth1.php b/library/OAuth1.php
index 27ee090b1..723f6592e 100644
--- a/library/OAuth1.php
+++ b/library/OAuth1.php
@@ -4,27 +4,30 @@
 /* Generic exception class
  */
 if (!class_exists('OAuthException', false)) {
-  class OAuthException extends Exception {
-    // pass
-  }
+  class OAuthException extends Exception
+  { }
 }
 
-class OAuthConsumer {
+class OAuthConsumer
+{
   public $key;
   public $secret;
 
-  function __construct($key, $secret, $callback_url=NULL) {
+  function __construct($key, $secret, $callback_url = NULL)
+  {
     $this->key = $key;
     $this->secret = $secret;
     $this->callback_url = $callback_url;
   }
 
-  function __toString() {
+  function __toString()
+  {
     return "OAuthConsumer[key=$this->key,secret=$this->secret]";
   }
 }
 
-class OAuthToken {
+class OAuthToken
+{
   // access tokens and request tokens
   public $key;
   public $secret;
@@ -37,7 +40,8 @@ class OAuthToken {
    * key = the token
    * secret = the token secret
    */
-  function __construct($key, $secret) {
+  function __construct($key, $secret)
+  {
     $this->key = $key;
     $this->secret = $secret;
   }
@@ -46,14 +50,16 @@ class OAuthToken {
    * generates the basic string serialization of a token that a server
    * would respond to request_token and access_token calls with
    */
-  function to_string() {
+  function to_string()
+  {
     return "oauth_token=" .
-           OAuthUtil::urlencode_rfc3986($this->key) .
-           "&oauth_token_secret=" .
-           OAuthUtil::urlencode_rfc3986($this->secret);
+      OAuthUtil::urlencode_rfc3986($this->key) .
+      "&oauth_token_secret=" .
+      OAuthUtil::urlencode_rfc3986($this->secret);
   }
 
-  function __toString() {
+  function __toString()
+  {
     return $this->to_string();
   }
 }
@@ -62,7 +68,8 @@ class OAuthToken {
  * A class for implementing a Signature Method
  * See section 9 ("Signing Requests") in the spec
  */
-abstract class OAuthSignatureMethod {
+abstract class OAuthSignatureMethod
+{
   /**
    * Needs to return the name of the Signature Method (ie HMAC-SHA1)
    * @return string
@@ -89,25 +96,29 @@ abstract class OAuthSignatureMethod {
    * @param string $signature
    * @return bool
    */
-  public function check_signature($request, $consumer, $token, $signature) {
+  public function check_signature($request, $consumer, $token, $signature)
+  {
     $built = $this->build_signature($request, $consumer, $token);
     return ($built == $signature);
   }
 }
 
 /**
- * The HMAC-SHA1 signature method uses the HMAC-SHA1 signature algorithm as defined in [RFC2104] 
- * where the Signature Base String is the text and the key is the concatenated values (each first 
- * encoded per Parameter Encoding) of the Consumer Secret and Token Secret, separated by an '&' 
+ * The HMAC-SHA1 signature method uses the HMAC-SHA1 signature algorithm as defined in [RFC2104]
+ * where the Signature Base String is the text and the key is the concatenated values (each first
+ * encoded per Parameter Encoding) of the Consumer Secret and Token Secret, separated by an '&'
  * character (ASCII code 38) even if empty.
  *   - Chapter 9.2 ("HMAC-SHA1")
  */
-class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod {
-  function get_name() {
+class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod
+{
+  function get_name()
+  {
     return "HMAC-SHA1";
   }
 
-  public function build_signature($request, $consumer, $token) {
+  public function build_signature($request, $consumer, $token)
+  {
     $base_string = $request->get_signature_base_string();
     $request->base_string = $base_string;
 
@@ -126,25 +137,28 @@ class OAuthSignatureMethod_HMAC_SHA1 extends OAuthSignatureMethod {
 }
 
 /**
- * The PLAINTEXT method does not provide any security protection and SHOULD only be used 
+ * The PLAINTEXT method does not provide any security protection and SHOULD only be used
  * over a secure channel such as HTTPS. It does not use the Signature Base String.
  *   - Chapter 9.4 ("PLAINTEXT")
  */
-class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod {
-  public function get_name() {
+class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod
+{
+  public function get_name()
+  {
     return "PLAINTEXT";
   }
 
   /**
-   * oauth_signature is set to the concatenated encoded values of the Consumer Secret and 
-   * Token Secret, separated by a '&' character (ASCII code 38), even if either secret is 
+   * oauth_signature is set to the concatenated encoded values of the Consumer Secret and
+   * Token Secret, separated by a '&' character (ASCII code 38), even if either secret is
    * empty. The result MUST be encoded again.
    *   - Chapter 9.4.1 ("Generating Signatures")
    *
    * Please note that the second encoding MUST NOT happen in the SignatureMethod, as
    * OAuthRequest handles this!
    */
-  public function build_signature($request, $consumer, $token) {
+  public function build_signature($request, $consumer, $token)
+  {
     $key_parts = array(
       $consumer->secret,
       ($token) ? $token->secret : ""
@@ -159,15 +173,17 @@ class OAuthSignatureMethod_PLAINTEXT extends OAuthSignatureMethod {
 }
 
 /**
- * The RSA-SHA1 signature method uses the RSASSA-PKCS1-v1_5 signature algorithm as defined in 
- * [RFC3447] section 8.2 (more simply known as PKCS#1), using SHA-1 as the hash function for 
- * EMSA-PKCS1-v1_5. It is assumed that the Consumer has provided its RSA public key in a 
- * verified way to the Service Provider, in a manner which is beyond the scope of this 
+ * The RSA-SHA1 signature method uses the RSASSA-PKCS1-v1_5 signature algorithm as defined in
+ * [RFC3447] section 8.2 (more simply known as PKCS#1), using SHA-1 as the hash function for
+ * EMSA-PKCS1-v1_5. It is assumed that the Consumer has provided its RSA public key in a
+ * verified way to the Service Provider, in a manner which is beyond the scope of this
  * specification.
  *   - Chapter 9.3 ("RSA-SHA1")
  */
-abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
-  public function get_name() {
+abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod
+{
+  public function get_name()
+  {
     return "RSA-SHA1";
   }
 
@@ -185,7 +201,8 @@ abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
   // Either way should return a string representation of the certificate
   protected abstract function fetch_private_cert(&$request);
 
-  public function build_signature($request, $consumer, $token) {
+  public function build_signature($request, $consumer, $token)
+  {
     $base_string = $request->get_signature_base_string();
     $request->base_string = $base_string;
 
@@ -204,7 +221,8 @@ abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
     return base64_encode($signature);
   }
 
-  public function check_signature($request, $consumer, $token, $signature) {
+  public function check_signature($request, $consumer, $token, $signature)
+  {
     $decoded_sig = base64_decode($signature);
 
     $base_string = $request->get_signature_base_string();
@@ -225,7 +243,8 @@ abstract class OAuthSignatureMethod_RSA_SHA1 extends OAuthSignatureMethod {
   }
 }
 
-class OAuthRequest {
+class OAuthRequest
+{
   private $parameters;
   private $http_method;
   private $http_url;
@@ -234,9 +253,10 @@ class OAuthRequest {
   public static $version = '1.0';
   public static $POST_INPUT = 'php://input';
 
-  function __construct($http_method, $http_url, $parameters=NULL) {
+  function __construct($http_method, $http_url, $parameters = NULL)
+  {
     @$parameters or $parameters = array();
-    $parameters = array_merge( OAuthUtil::parse_parameters(parse_url($http_url, PHP_URL_QUERY)), $parameters);
+    $parameters = array_merge(OAuthUtil::parse_parameters(parse_url($http_url, PHP_URL_QUERY)), $parameters);
     $this->parameters = $parameters;
     $this->http_method = $http_method;
     $this->http_url = $http_url;
@@ -246,15 +266,16 @@ class OAuthRequest {
   /**
    * attempt to build up a request from what was passed to the server
    */
-  public static function from_request($http_method=NULL, $http_url=NULL, $parameters=NULL) {
+  public static function from_request($http_method = NULL, $http_url = NULL, $parameters = NULL)
+  {
     $scheme = (!isset($_SERVER['HTTPS']) || $_SERVER['HTTPS'] != "on")
-              ? 'http'
-              : 'https';
+      ? 'http'
+      : 'https';
     @$http_url or $http_url = $scheme .
-                              '://' . $_SERVER['HTTP_HOST'] .
-                              ':' .
-                              $_SERVER['SERVER_PORT'] .
-                              $_SERVER['REQUEST_URI'];
+      '://' . $_SERVER['HTTP_HOST'] .
+      ':' .
+      $_SERVER['SERVER_PORT'] .
+      $_SERVER['REQUEST_URI'];
     @$http_method or $http_method = $_SERVER['REQUEST_METHOD'];
 
     // We weren't handed any parameters, so let's find the ones relevant to
@@ -270,10 +291,13 @@ class OAuthRequest {
 
       // It's a POST request of the proper content-type, so parse POST
       // parameters and add those overriding any duplicates from GET
-      if ($http_method == "POST"
-          && @strstr($request_headers["Content-Type"],
-                     "application/x-www-form-urlencoded")
-          ) {
+      if (
+        $http_method == "POST"
+        && @strstr(
+          $request_headers["Content-Type"],
+          "application/x-www-form-urlencoded"
+        )
+      ) {
         $post_data = OAuthUtil::parse_parameters(
           file_get_contents(self::$POST_INPUT)
         );
@@ -288,25 +312,27 @@ class OAuthRequest {
         );
         $parameters = array_merge($parameters, $header_parameters);
       }
-
     }
     // fix for friendica redirect system
-    
-    $http_url =  substr($http_url, 0, strpos($http_url,$parameters['pagename'])+strlen($parameters['pagename']));
-    unset( $parameters['pagename'] );
-    
+
+    $http_url =  substr($http_url, 0, strpos($http_url, $parameters['pagename']) + strlen($parameters['pagename']));
+    unset($parameters['pagename']);
+
     return new OAuthRequest($http_method, $http_url, $parameters);
   }
 
   /**
    * pretty much a helper function to set up the request
    */
-  public static function from_consumer_and_token($consumer, $token, $http_method, $http_url, $parameters=NULL) {
+  public static function from_consumer_and_token($consumer, $token, $http_method, $http_url, $parameters = NULL)
+  {
     @$parameters or $parameters = array();
-    $defaults = array("oauth_version" => OAuthRequest::$version,
-                      "oauth_nonce" => OAuthRequest::generate_nonce(),
-                      "oauth_timestamp" => OAuthRequest::generate_timestamp(),
-                      "oauth_consumer_key" => $consumer->key);
+    $defaults = array(
+      "oauth_version" => OAuthRequest::$version,
+      "oauth_nonce" => OAuthRequest::generate_nonce(),
+      "oauth_timestamp" => OAuthRequest::generate_timestamp(),
+      "oauth_consumer_key" => $consumer->key
+    );
     if ($token)
       $defaults['oauth_token'] = $token->key;
 
@@ -315,7 +341,8 @@ class OAuthRequest {
     return new OAuthRequest($http_method, $http_url, $parameters);
   }
 
-  public function set_parameter($name, $value, $allow_duplicates = true) {
+  public function set_parameter($name, $value, $allow_duplicates = true)
+  {
     if ($allow_duplicates && isset($this->parameters[$name])) {
       // We have already added parameter(s) with this name, so add to the list
       if (is_scalar($this->parameters[$name])) {
@@ -330,15 +357,18 @@ class OAuthRequest {
     }
   }
 
-  public function get_parameter($name) {
+  public function get_parameter($name)
+  {
     return isset($this->parameters[$name]) ? $this->parameters[$name] : null;
   }
 
-  public function get_parameters() {
+  public function get_parameters()
+  {
     return $this->parameters;
   }
 
-  public function unset_parameter($name) {
+  public function unset_parameter($name)
+  {
     unset($this->parameters[$name]);
   }
 
@@ -346,7 +376,8 @@ class OAuthRequest {
    * The request parameters, sorted and concatenated into a normalized string.
    * @return string
    */
-  public function get_signable_parameters() {
+  public function get_signable_parameters()
+  {
     // Grab all parameters
     $params = $this->parameters;
 
@@ -366,7 +397,8 @@ class OAuthRequest {
    * and the parameters (normalized), each urlencoded
    * and the concated with &.
    */
-  public function get_signature_base_string() {
+  public function get_signature_base_string()
+  {
     $parts = array(
       $this->get_normalized_http_method(),
       $this->get_normalized_http_url(),
@@ -381,7 +413,8 @@ class OAuthRequest {
   /**
    * just uppercases the http method
    */
-  public function get_normalized_http_method() {
+  public function get_normalized_http_method()
+  {
     return strtoupper($this->http_method);
   }
 
@@ -389,7 +422,8 @@ class OAuthRequest {
    * parses the url and rebuilds it to be
    * scheme://host/path
    */
-  public function get_normalized_http_url() {
+  public function get_normalized_http_url()
+  {
     $parts = parse_url($this->http_url);
 
     $port = @$parts['port'];
@@ -400,7 +434,8 @@ class OAuthRequest {
     $port or $port = ($scheme == 'https') ? '443' : '80';
 
     if (($scheme == 'https' && $port != '443')
-        || ($scheme == 'http' && $port != '80')) {
+      || ($scheme == 'http' && $port != '80')
+    ) {
       $host = "$host:$port";
     }
     return "$scheme://$host$path";
@@ -409,11 +444,12 @@ class OAuthRequest {
   /**
    * builds a url usable for a GET request
    */
-  public function to_url() {
+  public function to_url()
+  {
     $post_data = $this->to_postdata();
     $out = $this->get_normalized_http_url();
     if ($post_data) {
-      $out .= '?'.$post_data;
+      $out .= '?' . $post_data;
     }
     return $out;
   }
@@ -421,9 +457,10 @@ class OAuthRequest {
   /**
    * builds the data one would send in a POST request
    */
-  public function to_postdata($raw = false) {
+  public function to_postdata($raw = false)
+  {
     if ($raw)
-      return($this->parameters);
+      return $this->parameters;
     else
       return OAuthUtil::build_http_query($this->parameters);
   }
@@ -431,15 +468,15 @@ class OAuthRequest {
   /**
    * builds the Authorization: header
    */
-  public function to_header($realm=null) {
+  public function to_header($realm = null)
+  {
     $first = true;
-	if($realm) {
+    if ($realm) {
       $out = 'Authorization: OAuth realm="' . OAuthUtil::urlencode_rfc3986($realm) . '"';
       $first = false;
     } else
       $out = 'Authorization: OAuth';
 
-    $total = array();
     foreach ($this->parameters as $k => $v) {
       if (substr($k, 0, 5) != "oauth") continue;
       if (is_array($v)) {
@@ -447,20 +484,22 @@ class OAuthRequest {
       }
       $out .= ($first) ? ' ' : ',';
       $out .= OAuthUtil::urlencode_rfc3986($k) .
-              '="' .
-              OAuthUtil::urlencode_rfc3986($v) .
-              '"';
+        '="' .
+        OAuthUtil::urlencode_rfc3986($v) .
+        '"';
       $first = false;
     }
     return $out;
   }
 
-  public function __toString() {
+  public function __toString()
+  {
     return $this->to_url();
   }
 
 
-  public function sign_request($signature_method, $consumer, $token) {
+  public function sign_request($signature_method, $consumer, $token)
+  {
     $this->set_parameter(
       "oauth_signature_method",
       $signature_method->get_name(),
@@ -470,7 +509,8 @@ class OAuthRequest {
     $this->set_parameter("oauth_signature", $signature, false);
   }
 
-  public function build_signature($signature_method, $consumer, $token) {
+  public function build_signature($signature_method, $consumer, $token)
+  {
     $signature = $signature_method->build_signature($this, $consumer, $token);
     return $signature;
   }
@@ -478,33 +518,35 @@ class OAuthRequest {
   /**
    * util function: current timestamp
    */
-  private static function generate_timestamp() {
+  private static function generate_timestamp()
+  {
     return time();
   }
 
   /**
    * util function: current nonce
    */
-  private static function generate_nonce() {
-    $mt = microtime();
-    $rand = mt_rand();
-
-    return md5($mt . $rand); // md5s look nicer than numbers
+  private static function generate_nonce()
+  {
+    return bin2hex(random_bytes(16));
   }
 }
 
-class OAuthServer {
+class OAuthServer
+{
   protected $timestamp_threshold = 300; // in seconds, five minutes
   protected $version = '1.0';             // hi blaine
   protected $signature_methods = array();
 
   protected $data_store;
 
-  function __construct($data_store) {
+  function __construct($data_store)
+  {
     $this->data_store = $data_store;
   }
 
-  public function add_signature_method($signature_method) {
+  public function add_signature_method($signature_method)
+  {
     $this->signature_methods[$signature_method->get_name()] =
       $signature_method;
   }
@@ -515,7 +557,8 @@ class OAuthServer {
    * process a request_token request
    * returns the request token on success
    */
-  public function fetch_request_token(&$request) {
+  public function fetch_request_token(&$request)
+  {
     $this->get_version($request);
 
     $consumer = $this->get_consumer($request);
@@ -536,7 +579,8 @@ class OAuthServer {
    * process an access_token request
    * returns the access token on success
    */
-  public function fetch_access_token(&$request) {
+  public function fetch_access_token(&$request)
+  {
     $this->get_version($request);
 
     $consumer = $this->get_consumer($request);
@@ -556,22 +600,24 @@ class OAuthServer {
   /**
    * verify an api call, checks all the parameters
    */
-  public function verify_request(&$request) {
+  public function verify_request(&$request)
+  {
     $this->get_version($request);
     $consumer = $this->get_consumer($request);
     $token = $this->get_token($request, $consumer, "access");
     $this->check_signature($request, $consumer, $token);
-    return array($consumer, $token);
+    return [$consumer, $token];
   }
 
   // Internals from here
   /**
    * version 1
    */
-  private function get_version(&$request) {
+  private function get_version(&$request)
+  {
     $version = $request->get_parameter("oauth_version");
     if (!$version) {
-      // Service Providers MUST assume the protocol version to be 1.0 if this parameter is not present. 
+      // Service Providers MUST assume the protocol version to be 1.0 if this parameter is not present.
       // Chapter 7.0 ("Accessing Protected Ressources")
       $version = '1.0';
     }
@@ -584,9 +630,10 @@ class OAuthServer {
   /**
    * figure out the signature with some defaults
    */
-  private function get_signature_method(&$request) {
+  private function get_signature_method(&$request)
+  {
     $signature_method =
-        @$request->get_parameter("oauth_signature_method");
+      @$request->get_parameter("oauth_signature_method");
 
     if (!$signature_method) {
       // According to chapter 7 ("Accessing Protected Ressources") the signature-method
@@ -594,12 +641,14 @@ class OAuthServer {
       throw new OAuthException('No signature method parameter. This parameter is required');
     }
 
-    if (!in_array($signature_method,
-                  array_keys($this->signature_methods))) {
+    if (!in_array(
+      $signature_method,
+      array_keys($this->signature_methods)
+    )) {
       throw new OAuthException(
         "Signature method '$signature_method' not supported " .
-        "try one of the following: " .
-        implode(", ", array_keys($this->signature_methods))
+          "try one of the following: " .
+          implode(", ", array_keys($this->signature_methods))
       );
     }
     return $this->signature_methods[$signature_method];
@@ -608,7 +657,8 @@ class OAuthServer {
   /**
    * try to find the consumer for the provided request's consumer key
    */
-  private function get_consumer(&$request) {
+  private function get_consumer(&$request)
+  {
     $consumer_key = @$request->get_parameter("oauth_consumer_key");
     if (!$consumer_key) {
       throw new OAuthException("Invalid consumer key");
@@ -625,10 +675,13 @@ class OAuthServer {
   /**
    * try to find the token for the provided request's token key
    */
-  private function get_token(&$request, $consumer, $token_type="access") {
+  private function get_token(&$request, $consumer, $token_type = "access")
+  {
     $token_field = @$request->get_parameter('oauth_token');
     $token = $this->data_store->lookup_token(
-      $consumer, $token_type, $token_field
+      $consumer,
+      $token_type,
+      $token_field
     );
     if (!$token) {
       throw new OAuthException("Invalid $token_type token: $token_field");
@@ -640,7 +693,8 @@ class OAuthServer {
    * all-in-one function to check the signature on a request
    * should guess the signature method appropriately
    */
-  private function check_signature(&$request, $consumer, $token) {
+  private function check_signature(&$request, $consumer, $token)
+  {
     // this should probably be in a different method
     $timestamp = @$request->get_parameter('oauth_timestamp');
     $nonce = @$request->get_parameter('oauth_nonce');
@@ -657,7 +711,7 @@ class OAuthServer {
       $token,
       $signature
     );
-	
+
 
     if (!$valid_sig) {
       throw new OAuthException("Invalid signature");
@@ -667,12 +721,13 @@ class OAuthServer {
   /**
    * check that the timestamp is new enough
    */
-  private function check_timestamp($timestamp) {
-    if( ! $timestamp )
+  private function check_timestamp($timestamp)
+  {
+    if (!$timestamp)
       throw new OAuthException(
         'Missing timestamp parameter. The parameter is required'
       );
-    
+
     // verify that timestamp is recentish
     $now = time();
     if (abs($now - $timestamp) > $this->timestamp_threshold) {
@@ -685,8 +740,9 @@ class OAuthServer {
   /**
    * check that the nonce is not repeated
    */
-  private function check_nonce($consumer, $token, $nonce, $timestamp) {
-    if( ! $nonce )
+  private function check_nonce($consumer, $token, $nonce, $timestamp)
+  {
+    if (!$nonce)
       throw new OAuthException(
         'Missing nonce parameter. The parameter is required'
       );
@@ -702,65 +758,73 @@ class OAuthServer {
       throw new OAuthException("Nonce already used: $nonce");
     }
   }
-
 }
 
-class OAuthDataStore {
-  function lookup_consumer($consumer_key) {
+class OAuthDataStore
+{
+  function lookup_consumer($consumer_key)
+  {
     // implement me
   }
 
-  function lookup_token($consumer, $token_type, $token) {
+  function lookup_token($consumer, $token_type, $token)
+  {
     // implement me
   }
 
-  function lookup_nonce($consumer, $token, $nonce, $timestamp) {
+  function lookup_nonce($consumer, $token, $nonce, $timestamp)
+  {
     // implement me
   }
 
-  function new_request_token($consumer, $callback = null) {
+  function new_request_token($consumer, $callback = null)
+  {
     // return a new token attached to this consumer
   }
 
-  function new_access_token($token, $consumer, $verifier = null) {
+  function new_access_token($token, $consumer, $verifier = null)
+  {
     // return a new access token attached to this consumer
     // for the user associated with this token if the request token
     // is authorized
     // should also invalidate the request token
   }
-
 }
 
-class OAuthUtil {
-  public static function urlencode_rfc3986($input) {
-  if (is_array($input)) {
-    return array_map(array('OAuthUtil', 'urlencode_rfc3986'), $input);
-  } else if (is_scalar($input)) {
-    return str_replace(
-      '+',
-      ' ',
-      str_replace('%7E', '~', rawurlencode($input))
-    );
-  } else {
-    return '';
+class OAuthUtil
+{
+  public static function urlencode_rfc3986($input)
+  {
+    if (is_array($input)) {
+      return array_map(['OAuthUtil', 'urlencode_rfc3986'], $input);
+    } else if (is_scalar($input)) {
+      return str_replace(
+        '+',
+        ' ',
+        str_replace('%7E', '~', rawurlencode($input))
+      );
+    } else {
+      return '';
+    }
   }
-}
 
 
   // This decode function isn't taking into consideration the above
   // modifications to the encoding process. However, this method doesn't
   // seem to be used anywhere so leaving it as is.
-  public static function urldecode_rfc3986($string) {
+  public static function urldecode_rfc3986($string)
+  {
     return urldecode($string);
   }
 
   // Utility function for turning the Authorization: header into
   // parameters, has to do some unescaping
   // Can filter out any non-oauth parameters if needed (default behaviour)
-  public static function split_header($header, $only_allow_oauth_parameters = true) {
+  public static function split_header($header, $only_allow_oauth_parameters = true)
+  {
     $pattern = '/(([-_a-z]*)=("([^"]*)"|([^,]*)),?)/';
     $offset = 0;
-    $params = array();
+    $params = [];
     while (preg_match($pattern, $header, $matches, PREG_OFFSET_CAPTURE, $offset) > 0) {
       $match = $matches[0];
       $header_name = $matches[2][0];
@@ -779,7 +843,8 @@ class OAuthUtil {
   }
 
   // helper to try to sort out headers for people who aren't running apache
-  public static function get_headers() {
+  public static function get_headers()
+  {
     if (function_exists('apache_request_headers')) {
       // we need this to get the actual Authorization: header
       // because apache tends to tell us it doesn't exist
@@ -789,22 +854,22 @@ class OAuthUtil {
       // we always want the keys to be Cased-Like-This and arh()
       // returns the headers in the same case as they are in the
       // request
-      $out = array();
-      foreach( $headers AS $key => $value ) {
+      $out = [];
+      foreach ($headers as $key => $value) {
         $key = str_replace(
-            " ",
-            "-",
-            ucwords(strtolower(str_replace("-", " ", $key)))
-          );
+          " ",
+          "-",
+          ucwords(strtolower(str_replace("-", " ", $key)))
+        );
         $out[$key] = $value;
       }
     } else {
       // otherwise we don't have apache and are just going to have to hope
       // that $_SERVER actually contains what we need
-      $out = array();
-      if( isset($_SERVER['CONTENT_TYPE']) )
+      $out = [];
+      if (isset($_SERVER['CONTENT_TYPE']))
         $out['Content-Type'] = $_SERVER['CONTENT_TYPE'];
-      if( isset($_ENV['CONTENT_TYPE']) )
+      if (isset($_ENV['CONTENT_TYPE']))
         $out['Content-Type'] = $_ENV['CONTENT_TYPE'];
 
       foreach ($_SERVER as $key => $value) {
@@ -827,12 +892,13 @@ class OAuthUtil {
   // This function takes a input like a=b&a=c&d=e and returns the parsed
   // parameters like this
   // array('a' => array('b','c'), 'd' => 'e')
-  public static function parse_parameters( $input ) {
+  public static function parse_parameters($input)
+  {
     if (!isset($input) || !$input) return array();
 
     $pairs = explode('&', $input);
 
-    $parsed_parameters = array();
+    $parsed_parameters = [];
     foreach ($pairs as $pair) {
       $split = explode('=', $pair, 2);
       $parameter = OAuthUtil::urldecode_rfc3986($split[0]);
@@ -845,7 +911,7 @@ class OAuthUtil {
         if (is_scalar($parsed_parameters[$parameter])) {
           // This is the first duplicate, so transform scalar (string) into an array
           // so we can add the duplicates
-          $parsed_parameters[$parameter] = array($parsed_parameters[$parameter]);
+          $parsed_parameters[$parameter] = [$parsed_parameters[$parameter]];
         }
 
         $parsed_parameters[$parameter][] = $value;
@@ -856,7 +922,8 @@ class OAuthUtil {
     return $parsed_parameters;
   }
 
-  public static function build_http_query($params) {
+  public static function build_http_query($params)
+  {
     if (!$params) return '';
 
     // Urlencode both keys and values
@@ -868,7 +935,7 @@ class OAuthUtil {
     // Ref: Spec: 9.1.1 (1)
     uksort($params, 'strcmp');
 
-    $pairs = array();
+    $pairs = [];
     foreach ($params as $parameter => $value) {
       if (is_array($value)) {
         // If two or more parameters share the same name, they are sorted by their value
@@ -886,5 +953,3 @@ class OAuthUtil {
     return implode('&', $pairs);
   }
 }
-
-?>
diff --git a/mod/lostpass.php b/mod/lostpass.php
index 01e84268b..ecab0982c 100644
--- a/mod/lostpass.php
+++ b/mod/lostpass.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file mod/lostpass.php
  */
@@ -27,7 +28,7 @@ function lostpass_post(App $a)
 		$a->internalRedirect();
 	}
 
-	$pwdreset_token = Strings::getRandomName(12) . mt_rand(1000, 9999);
+	$pwdreset_token = Strings::getRandomName(12) . random_int(1000, 9999);
 
 	$fields = [
 		'pwdreset' => $pwdreset_token,
diff --git a/src/Core/Authentication.php b/src/Core/Authentication.php
index 59061c04c..fd34dbc88 100644
--- a/src/Core/Authentication.php
+++ b/src/Core/Authentication.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file /src/Core/Authentication.php
  */
@@ -10,8 +11,8 @@ use Friendica\BaseObject;
 use Friendica\Network\HTTPException\ForbiddenException;
 
 /**
-* Handle Authentification, Session and Cookies
-*/
+ * Handle Authentification, Session and Cookies
+ */
 class Authentication extends BaseObject
 {
 	/**
@@ -24,9 +25,11 @@ class Authentication extends BaseObject
 	 */
 	public static function getCookieHashForUser($user)
 	{
-		return(hash("sha256", Config::get("system", "site_prvkey") .
-				$user["prvkey"] .
-				$user["password"]));
+		return hash_hmac(
+			"sha256",
+			hash_hmac("sha256", $user["password"], $user["privkey"]),
+			Config::get("system", "site_prvkey")
+		);
 	}
 
 	/**
@@ -43,9 +46,11 @@ class Authentication extends BaseObject
 		}
 
 		if ($user) {
-			$value = json_encode(["uid" => $user["uid"],
+			$value = json_encode([
+				"uid" => $user["uid"],
 				"hash" => self::getCookieHashForUser($user),
-				"ip" => defaults($_SERVER, 'REMOTE_ADDR', '0.0.0.0')]);
+				"ip" => defaults($_SERVER, 'REMOTE_ADDR', '0.0.0.0')
+			]);
 		} else {
 			$value = "";
 		}
@@ -88,4 +93,3 @@ class Authentication extends BaseObject
 		}
 	}
 }
-
diff --git a/src/Model/Register.php b/src/Model/Register.php
index 8a03f379a..9f6d36974 100644
--- a/src/Model/Register.php
+++ b/src/Model/Register.php
@@ -3,6 +3,7 @@
 /**
  * @file src/Model/Register.php
  */
+
 namespace Friendica\Model;
 
 use Friendica\Database\DBA;
@@ -83,7 +84,7 @@ class Register
 	 */
 	public static function createForInvitation()
 	{
-		$code = Strings::getRandomName(8) . srand(1000, 9999);
+		$code = Strings::getRandomName(8) . random_int(1000, 9999);
 
 		$fields = [
 			'hash' => $code,
diff --git a/src/Model/User.php b/src/Model/User.php
index 141ecf059..b6121ad04 100644
--- a/src/Model/User.php
+++ b/src/Model/User.php
@@ -1,8 +1,10 @@
 <?php
+
 /**
  * @file src/Model/User.php
  * @brief This file includes the User class with user related database functions
  */
+
 namespace Friendica\Model;
 
 use DivineOmega\PasswordExposed;
@@ -155,8 +157,10 @@ class User
 	 * @return boolean|array
 	 * @throws Exception
 	 */
-	public static function getOwnerDataById($uid, $check_valid = true) {
-		$r = DBA::fetchFirst("SELECT
+	public static function getOwnerDataById($uid, $check_valid = true)
+	{
+		$r = DBA::fetchFirst(
+			"SELECT
 			`contact`.*,
 			`user`.`prvkey` AS `uprvkey`,
 			`user`.`timezone`,
@@ -355,7 +359,8 @@ class User
 				$user = $user_info;
 			}
 
-			if (!isset($user['uid'])
+			if (
+				!isset($user['uid'])
 				|| !isset($user['password'])
 				|| !isset($user['legacy_password'])
 			) {
@@ -363,7 +368,9 @@ class User
 			}
 		} elseif (is_int($user_info) || is_string($user_info)) {
 			if (is_int($user_info)) {
-				$user = DBA::selectFirst('user', ['uid', 'password', 'legacy_password'],
+				$user = DBA::selectFirst(
+					'user',
+					['uid', 'password', 'legacy_password'],
 					[
 						'uid' => $user_info,
 						'blocked' => 0,
@@ -374,9 +381,11 @@ class User
 				);
 			} else {
 				$fields = ['uid', 'password', 'legacy_password'];
-				$condition = ["(`email` = ? OR `username` = ? OR `nickname` = ?)
+				$condition = [
+					"(`email` = ? OR `username` = ? OR `nickname` = ?)
 					AND NOT `blocked` AND NOT `account_expired` AND NOT `account_removed` AND `verified`",
-					$user_info, $user_info, $user_info];
+					$user_info, $user_info, $user_info
+				];
 				$user = DBA::selectFirst('user', $fields, $condition);
 			}
 
@@ -395,7 +404,7 @@ class User
 	 */
 	public static function generateNewPassword()
 	{
-		return ucfirst(Strings::getRandomName(8)) . mt_rand(1000, 9999);
+		return ucfirst(Strings::getRandomName(8)) . random_int(1000, 9999);
 	}
 
 	/**
@@ -671,7 +680,8 @@ class User
 		}
 
 		// Check existing and deleted accounts for this nickname.
-		if (DBA::exists('user', ['nickname' => $nickname])
+		if (
+			DBA::exists('user', ['nickname' => $nickname])
 			|| DBA::exists('userd', ['username' => $nickname])
 		) {
 			throw new Exception(L10n::t('Nickname is already registered. Please choose another.'));
@@ -839,7 +849,8 @@ class User
 	 */
 	public static function sendRegisterPendingEmail($user, $sitename, $siteurl, $password)
 	{
-		$body = Strings::deindent(L10n::t('
+		$body = Strings::deindent(L10n::t(
+			'
 			Dear %1$s,
 				Thank you for registering at %2$s. Your account is pending for approval by the administrator.
 
@@ -849,7 +860,11 @@ class User
 			Login Name:		%4$s
 			Password:		%5$s
 		',
-			$user['username'], $sitename, $siteurl, $user['nickname'], $password
+			$user['username'],
+			$sitename,
+			$siteurl,
+			$user['nickname'],
+			$password
 		));
 
 		return notification([
@@ -875,13 +890,16 @@ class User
 	 */
 	public static function sendRegisterOpenEmail($user, $sitename, $siteurl, $password)
 	{
-		$preamble = Strings::deindent(L10n::t('
-			Dear %1$s,
+		$preamble = Strings::deindent(L10n::t(
+			'
+				Dear %1$s,
 				Thank you for registering at %2$s. Your account has been created.
-		',
-			$user['username'], $sitename
+			',
+			$user['username'],
+			$sitename
 		));
-		$body = Strings::deindent(L10n::t('
+		$body = Strings::deindent(L10n::t(
+			'
 			The login details are as follows:
 
 			Site Location:	%3$s
@@ -908,7 +926,11 @@ class User
 			If you ever want to delete your account, you can do so at %3$s/removeme
 
 			Thank you and welcome to %2$s.',
-			$user['nickname'], $sitename, $siteurl, $user['username'], $password
+			$user['nickname'],
+			$sitename,
+			$siteurl,
+			$user['username'],
+			$password
 		));
 
 		return notification([
@@ -989,33 +1011,45 @@ class User
 
 		if ($user['parent-uid'] == 0) {
 			// First add our own entry
-			$identities = [['uid' => $user['uid'],
+			$identities = [[
+				'uid' => $user['uid'],
 				'username' => $user['username'],
-				'nickname' => $user['nickname']]];
+				'nickname' => $user['nickname']
+			]];
 
 			// Then add all the children
-			$r = DBA::select('user', ['uid', 'username', 'nickname'],
-				['parent-uid' => $user['uid'], 'account_removed' => false]);
+			$r = DBA::select(
+				'user',
+				['uid', 'username', 'nickname'],
+				['parent-uid' => $user['uid'], 'account_removed' => false]
+			);
 			if (DBA::isResult($r)) {
 				$identities = array_merge($identities, DBA::toArray($r));
 			}
 		} else {
 			// First entry is our parent
-			$r = DBA::select('user', ['uid', 'username', 'nickname'],
-				['uid' => $user['parent-uid'], 'account_removed' => false]);
+			$r = DBA::select(
+				'user',
+				['uid', 'username', 'nickname'],
+				['uid' => $user['parent-uid'], 'account_removed' => false]
+			);
 			if (DBA::isResult($r)) {
 				$identities = DBA::toArray($r);
 			}
 
 			// Then add all siblings
-			$r = DBA::select('user', ['uid', 'username', 'nickname'],
-				['parent-uid' => $user['parent-uid'], 'account_removed' => false]);
+			$r = DBA::select(
+				'user',
+				['uid', 'username', 'nickname'],
+				['parent-uid' => $user['parent-uid'], 'account_removed' => false]
+			);
 			if (DBA::isResult($r)) {
 				$identities = array_merge($identities, DBA::toArray($r));
 			}
 		}
 
-		$r = DBA::p("SELECT `user`.`uid`, `user`.`username`, `user`.`nickname`
+		$r = DBA::p(
+			"SELECT `user`.`uid`, `user`.`username`, `user`.`nickname`
 			FROM `manage`
 			INNER JOIN `user` ON `manage`.`mid` = `user`.`uid`
 			WHERE `user`.`account_removed` = 0 AND `manage`.`uid` = ?",
@@ -1061,13 +1095,13 @@ class User
 		while ($user = DBA::fetch($userStmt)) {
 			$statistics['total_users']++;
 
-			if ((strtotime($user['login_date']) > $halfyear) ||
-				(strtotime($user['last-item']) > $halfyear)) {
+			if ((strtotime($user['login_date']) > $halfyear) || (strtotime($user['last-item']) > $halfyear)
+			) {
 				$statistics['active_users_halfyear']++;
 			}
 
-			if ((strtotime($user['login_date']) > $month) ||
-				(strtotime($user['last-item']) > $month)) {
+			if ((strtotime($user['login_date']) > $month) || (strtotime($user['last-item']) > $month)
+			) {
 				$statistics['active_users_monthly']++;
 			}
 		}
diff --git a/src/Module/Login.php b/src/Module/Login.php
index 40e376aeb..a8c9f9fb9 100644
--- a/src/Module/Login.php
+++ b/src/Module/Login.php
@@ -1,7 +1,9 @@
 <?php
+
 /**
  * @file src/Module/Login.php
  */
+
 namespace Friendica\Module;
 
 use Exception;
@@ -48,10 +50,8 @@ class Login extends BaseModule
 		// OpenId Login
 		if (
 			empty($_POST['password'])
-			&& (
-				!empty($_POST['openid_url'])
-				|| !empty($_POST['username'])
-			)
+			&& (!empty($_POST['openid_url'])
+				|| !empty($_POST['username']))
 		) {
 			$openid_url = trim(defaults($_POST, 'openid_url', $_POST['username']));
 
@@ -136,7 +136,9 @@ class Login extends BaseModule
 					throw new Exception(L10n::t('Login failed.'));
 				}
 			} else {
-				$record = DBA::selectFirst('user', [],
+				$record = DBA::selectFirst(
+					'user',
+					[],
 					['uid' => User::getIdFromPasswordAuthentication($username, $password)]
 				);
 			}
@@ -176,7 +178,9 @@ class Login extends BaseModule
 			$data = json_decode($_COOKIE["Friendica"]);
 			if (isset($data->uid)) {
 
-				$user = DBA::selectFirst('user', [],
+				$user = DBA::selectFirst(
+					'user',
+					[],
 					[
 						'uid'             => $data->uid,
 						'blocked'         => false,
@@ -186,7 +190,13 @@ class Login extends BaseModule
 					]
 				);
 				if (DBA::isResult($user)) {
-					if ($data->hash != Authentication::getCookieHashForUser($user)) {
+					// Time safe comparision of the two hashes.
+					$validSession = hash_equals(
+						Authentication::getCookieHashForUser($user),
+						$data->hash
+					);
+
+					if (!$validSession) {
 						Logger::log("Hash for user " . $data->uid . " doesn't fit.");
 						Authentication::deleteSession();
 						$a->internalRedirect();
@@ -229,7 +239,9 @@ class Login extends BaseModule
 					$a->internalRedirect();
 				}
 
-				$user = DBA::selectFirst('user', [],
+				$user = DBA::selectFirst(
+					'user',
+					[],
 					[
 						'uid'             => $_SESSION['uid'],
 						'blocked'         => false,
@@ -312,12 +324,12 @@ class Login extends BaseModule
 				'$logout'       => L10n::t('Logout'),
 				'$login'        => L10n::t('Login'),
 
-				'$lname'        => ['username', L10n::t('Nickname or Email: ') , '', ''],
+				'$lname'        => ['username', L10n::t('Nickname or Email: '), '', ''],
 				'$lpassword'    => ['password', L10n::t('Password: '), '', ''],
 				'$lremember'    => ['remember', L10n::t('Remember me'), 0,  ''],
 
 				'$openid'       => !$noid,
-				'$lopenid'      => ['openid_url', L10n::t('Or login using OpenID: '),'',''],
+				'$lopenid'      => ['openid_url', L10n::t('Or login using OpenID: '), '', ''],
 
 				'$hiddens'      => $hiddens,
 
diff --git a/src/Network/FKOAuthDataStore.php b/src/Network/FKOAuthDataStore.php
index d1f43172b..9fba89685 100644
--- a/src/Network/FKOAuthDataStore.php
+++ b/src/Network/FKOAuthDataStore.php
@@ -29,7 +29,7 @@ class FKOAuthDataStore extends OAuthDataStore
 	 */
 	private static function genToken()
 	{
-		return md5(base64_encode(pack('N6', mt_rand(), mt_rand(), mt_rand(), mt_rand(), mt_rand(), uniqid())));
+		return bin2hex(random_bytes(16));
 	}
 
 	/**
@@ -119,7 +119,8 @@ class FKOAuthDataStore extends OAuthDataStore
 				'secret' => $sec,
 				'client_id' => $k,
 				'scope' => 'request',
-				'expires' => time() + REQUEST_TOKEN_DURATION]
+				'expires' => time() + REQUEST_TOKEN_DURATION
+			]
 		);
 
 		if (!$r) {
@@ -162,7 +163,8 @@ class FKOAuthDataStore extends OAuthDataStore
 					'client_id' => $consumer->key,
 					'scope' => 'access',
 					'expires' => time() + ACCESS_TOKEN_DURATION,
-					'uid' => $uverifier]
+					'uid' => $uverifier
+				]
 			);
 
 			if ($r) {
diff --git a/src/Util/Strings.php b/src/Util/Strings.php
index 88dd1d39f..cd065aed1 100644
--- a/src/Util/Strings.php
+++ b/src/Util/Strings.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * @file src/Util/Strings.php
  */
@@ -13,13 +14,13 @@ use Friendica\Core\Logger;
  */
 class Strings
 {
-	/**
-	 * @brief Generates a pseudo-random string of hexadecimal characters
-	 *
-	 * @param int $size
-	 * @return string
-	 * @throws \Exception
-	 */
+    /**
+     * @brief Generates a pseudo-random string of hexadecimal characters
+     *
+     * @param int $size
+     * @return string
+     * @throws \Exception
+     */
     public static function getRandomHex($size = 64)
     {
         $byte_size = ceil($size / 2);
@@ -31,16 +32,16 @@ class Strings
         return $return;
     }
 
-	/**
-	 * Checks, if the given string is a valid hexadecimal code
-	 *
-	 * @param string $hexCode
-	 *
-	 * @return bool
-	 */
+    /**
+     * Checks, if the given string is a valid hexadecimal code
+     *
+     * @param string $hexCode
+     *
+     * @return bool
+     */
     public static function isHex($hexCode)
     {
-	    return !empty($hexCode) ? @preg_match("/^[a-f0-9]{2,}$/i", $hexCode) && !(strlen($hexCode) & 1) : false;
+        return !empty($hexCode) ? @preg_match("/^[a-f0-9]{2,}$/i", $hexCode) && !(strlen($hexCode) & 1) : false;
     }
 
     /**
@@ -62,19 +63,19 @@ class Strings
      * @brief Use this on "body" or "content" input where angle chars shouldn't be removed,
      * and allow them to be safely displayed.
      * @param string $string
-     * 
+     *
      * @return string
      */
     public static function escapeHtml($string)
     {
-        return htmlspecialchars($string, ENT_COMPAT, 'UTF-8', false);
+        return htmlentities($string, ENT_QUOTES | ENT_HTML5, "UTF-8", false);
     }
 
     /**
      * @brief Generate a string that's random, but usually pronounceable. Used to generate initial passwords
-     * 
+     *
      * @param int $len  length
-     * 
+     *
      * @return string
      */
     public static function getRandomName($len)
@@ -85,40 +86,44 @@ class Strings
 
         $vowels = ['a', 'a', 'ai', 'au', 'e', 'e', 'e', 'ee', 'ea', 'i', 'ie', 'o', 'ou', 'u'];
 
-        if (mt_rand(0, 5) == 4) {
+        if (random_int(0, 5) == 4) {
             $vowels[] = 'y';
         }
 
         $cons = [
-                'b', 'bl', 'br',
-                'c', 'ch', 'cl', 'cr',
-                'd', 'dr',
-                'f', 'fl', 'fr',
-                'g', 'gh', 'gl', 'gr',
-                'h',
-                'j',
-                'k', 'kh', 'kl', 'kr',
-                'l',
-                'm',
-                'n',
-                'p', 'ph', 'pl', 'pr',
-                'qu',
-                'r', 'rh',
-                's' ,'sc', 'sh', 'sm', 'sp', 'st',
-                't', 'th', 'tr',
-                'v',
-                'w', 'wh',
-                'x',
-                'z', 'zh'
-            ];
+            'b', 'bl', 'br',
+            'c', 'ch', 'cl', 'cr',
+            'd', 'dr',
+            'f', 'fl', 'fr',
+            'g', 'gh', 'gl', 'gr',
+            'h',
+            'j',
+            'k', 'kh', 'kl', 'kr',
+            'l',
+            'm',
+            'n',
+            'p', 'ph', 'pl', 'pr',
+            'qu',
+            'r', 'rh',
+            's', 'sc', 'sh', 'sm', 'sp', 'st',
+            't', 'th', 'tr',
+            'v',
+            'w', 'wh',
+            'x',
+            'z', 'zh'
+        ];
 
-        $midcons = ['ck', 'ct', 'gn', 'ld', 'lf', 'lm', 'lt', 'mb', 'mm', 'mn', 'mp',
-                    'nd', 'ng', 'nk', 'nt', 'rn', 'rp', 'rt'];
+        $midcons = [
+            'ck', 'ct', 'gn', 'ld', 'lf', 'lm', 'lt', 'mb', 'mm', 'mn', 'mp',
+            'nd', 'ng', 'nk', 'nt', 'rn', 'rp', 'rt'
+        ];
 
-        $noend = ['bl', 'br', 'cl', 'cr', 'dr', 'fl', 'fr', 'gl', 'gr',
-                    'kh', 'kl', 'kr', 'mn', 'pl', 'pr', 'rh', 'tr', 'qu', 'wh', 'q'];
+        $noend = [
+            'bl', 'br', 'cl', 'cr', 'dr', 'fl', 'fr', 'gl', 'gr',
+            'kh', 'kl', 'kr', 'mn', 'pl', 'pr', 'rh', 'tr', 'qu', 'wh', 'q'
+        ];
 
-        $start = mt_rand(0, 2);
+        $start = random_int(0, 2);
         if ($start == 0) {
             $table = $vowels;
         } else {
@@ -127,8 +132,8 @@ class Strings
 
         $word = '';
 
-        for ($x = 0; $x < $len; $x ++) {
-            $r = mt_rand(0, count($table) - 1);
+        for ($x = 0; $x < $len; $x++) {
+            $r = random_int(0, count($table) - 1);
             $word .= $table[$r];
 
             if ($table == $vowels) {
@@ -136,7 +141,6 @@ class Strings
             } else {
                 $table = $vowels;
             }
-
         }
 
         $word = substr($word, 0, $len);
@@ -152,20 +156,20 @@ class Strings
         return $word;
     }
 
-	/**
-	 * Translate and format the network name of a contact
-	 *
-	 * @param string $network Network name of the contact (e.g. dfrn, rss and so on)
-	 * @param string $url     The contact url
-	 *
-	 * @return string Formatted network name
-	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
-	 */
+    /**
+     * Translate and format the network name of a contact
+     *
+     * @param string $network Network name of the contact (e.g. dfrn, rss and so on)
+     * @param string $url     The contact url
+     *
+     * @return string Formatted network name
+     * @throws \Friendica\Network\HTTPException\InternalServerErrorException
+     */
     public static function formatNetworkName($network, $url = '')
     {
         if ($network != '') {
             if ($url != '') {
-                $network_name = '<a href="' . $url  .'">' . ContactSelector::networkToName($network, $url) . '</a>';
+                $network_name = '<a href="' . $url . '">' . ContactSelector::networkToName($network, $url) . '</a>';
             } else {
                 $network_name = ContactSelector::networkToName($network);
             }
@@ -176,11 +180,11 @@ class Strings
 
     /**
      * @brief Remove indentation from a text
-     * 
+     *
      * @param string $text  String to be transformed.
      * @param string $chr   Optional. Indentation tag. Default tab (\t).
      * @param int    $count Optional. Default null.
-     * 
+     *
      * @return string       Transformed string.
      */
     public static function deindent($text, $chr = "[\t ]", $count = NULL)
@@ -206,10 +210,10 @@ class Strings
 
     /**
      * @brief Get byte size returned in a Data Measurement (KB, MB, GB)
-     * 
+     *
      * @param int $bytes    The number of bytes to be measured
      * @param int $precision    Optional. Default 2.
-     * 
+     *
      * @return string   Size with measured units.
      */
     public static function formatBytes($bytes, $precision = 2)
@@ -225,9 +229,9 @@ class Strings
 
     /**
      * @brief Protect percent characters in sprintf calls
-     * 
+     *
      * @param string $s String to transform.
-     * 
+     *
      * @return string   Transformed string.
      */
     public static function protectSprintf($s)
@@ -237,10 +241,10 @@ class Strings
 
     /**
      * @brief Base64 Encode URL and translate +/ to -_ Optionally strip padding.
-     * 
+     *
      * @param string $s                 URL to encode
      * @param boolean $strip_padding    Optional. Default false
-     * 
+     *
      * @return string   Encoded URL
      */
     public static function base64UrlEncode($s, $strip_padding = false)
@@ -254,13 +258,13 @@ class Strings
         return $s;
     }
 
-	/**
-	 * @brief Decode Base64 Encoded URL and translate -_ to +/
-	 * @param string $s URL to decode
-	 *
-	 * @return string   Decoded URL
-	 * @throws \Exception
-	 */
+    /**
+     * @brief Decode Base64 Encoded URL and translate -_ to +/
+     * @param string $s URL to decode
+     *
+     * @return string   Decoded URL
+     * @throws \Exception
+     */
     public static function base64UrlDecode($s)
     {
         if (is_array($s)) {
@@ -291,7 +295,7 @@ class Strings
      * @brief Normalize url
      *
      * @param string $url   URL to be normalized.
-     * 
+     *
      * @return string   Normalized URL.
      */
     public static function normaliseLink($url)
@@ -302,9 +306,9 @@ class Strings
 
     /**
      * @brief Normalize OpenID identity
-     * 
+     *
      * @param string $s OpenID Identity
-     * 
+     *
      * @return string   normalized OpenId Identity
      */
     public static function normaliseOpenID($s)
@@ -329,51 +333,51 @@ class Strings
     }
 
 
-	/**
-	 * Ensures the provided URI has its query string punctuation in order.
-	 *
-	 * @param string $uri
-	 * @return string
-	 */
-	public static function ensureQueryParameter($uri)
-	{
-		if (strpos($uri, '?') === false && ($pos = strpos($uri, '&')) !== false) {
-			$uri = substr($uri, 0, $pos) . '?' . substr($uri, $pos + 1);
-		}
+    /**
+     * Ensures the provided URI has its query string punctuation in order.
+     *
+     * @param string $uri
+     * @return string
+     */
+    public static function ensureQueryParameter($uri)
+    {
+        if (strpos($uri, '?') === false && ($pos = strpos($uri, '&')) !== false) {
+            $uri = substr($uri, 0, $pos) . '?' . substr($uri, $pos + 1);
+        }
 
-		return $uri;
-	}
+        return $uri;
+    }
 
 
-	/**
-	 * Check if the trimmed provided string is starting with one of the provided characters
-	 *
-	 * @param string $string
-	 * @param array  $chars
-	 * @return bool
-	 */
-	public static function startsWith($string, array $chars)
-	{
-		$return = in_array(substr(trim($string), 0, 1), $chars);
+    /**
+     * Check if the trimmed provided string is starting with one of the provided characters
+     *
+     * @param string $string
+     * @param array  $chars
+     * @return bool
+     */
+    public static function startsWith($string, array $chars)
+    {
+        $return = in_array(substr(trim($string), 0, 1), $chars);
 
-		return $return;
-	}
+        return $return;
+    }
 
-	/**
-	 * Returns the regular expression string to match URLs in a given text
-	 *
-	 * @return string
-	 * @see https://daringfireball.net/2010/07/improved_regex_for_matching_urls
-	 */
-	public static function autoLinkRegEx()
-	{
-		return '@
+    /**
+     * Returns the regular expression string to match URLs in a given text
+     *
+     * @return string
+     * @see https://daringfireball.net/2010/07/improved_regex_for_matching_urls
+     */
+    public static function autoLinkRegEx()
+    {
+        return '@
 (?<![=\'\]"/])          # Not preceded by [, =, \', ], ", /
 \b
 (                              # Capture 1: entire matched URL
   https?://                            # http or https protocol
   (?:
-    [^/\s\xA0`!()\[\]{};:\'",<>?«»“”‘’.]    # Domain can\'t start with a . 
+    [^/\s\xA0`!()\[\]{};:\'",<>?«»“”‘’.]    # Domain can\'t start with a .
     [^/\s\xA0`!()\[\]{};:\'",<>?«»“”‘’]+    # Domain can\'t end with a .
     \.
     [^/\s\xA0`!()\[\]{};:\'".,<>?«»“”‘’]+/? # Followed by a slash
@@ -386,21 +390,21 @@ class Strings
     [^\s\xA0`!()\[\]{};:\'".,<>?«»“”‘’]    # not a space or one of these punct chars
   )*
 )@xiu';
-	}
+    }
 
-	/**
-	 * Ensures a single path item doesn't contain any path-traversing characters
-	 *
-	 * @see https://stackoverflow.com/a/46097713
-	 * @param string $pathItem
-	 * @return string
-	 */
-	public static function sanitizeFilePathItem($pathItem)
-	{
-		$pathItem = str_replace('/', '_', $pathItem);
-		$pathItem = str_replace('\\', '_', $pathItem);
-		$pathItem = str_replace(DIRECTORY_SEPARATOR, '_', $pathItem); // In case it does not equal the standard values
+    /**
+     * Ensures a single path item doesn't contain any path-traversing characters
+     *
+     * @see https://stackoverflow.com/a/46097713
+     * @param string $pathItem
+     * @return string
+     */
+    public static function sanitizeFilePathItem($pathItem)
+    {
+        $pathItem = str_replace('/', '_', $pathItem);
+        $pathItem = str_replace('\\', '_', $pathItem);
+        $pathItem = str_replace(DIRECTORY_SEPARATOR, '_', $pathItem); // In case it does not equal the standard values
 
-		return $pathItem;
-	}
+        return $pathItem;
+    }
 }

From dc01bdbc80cd382e33f61a21ce836a1e44a6c44c Mon Sep 17 00:00:00 2001
From: dew-git <55564947+dew-git@users.noreply.github.com>
Date: Thu, 10 Oct 2019 20:43:32 -0800
Subject: [PATCH 2/6] Use the utility instead.

---
 library/OAuth1.php               | 2 +-
 src/Network/FKOAuthDataStore.php | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/OAuth1.php b/library/OAuth1.php
index 723f6592e..e3ca24646 100644
--- a/library/OAuth1.php
+++ b/library/OAuth1.php
@@ -528,7 +528,7 @@ class OAuthRequest
    */
   private static function generate_nonce()
   {
-    return bin2hex(random_bytes(16));
+    return Friendica\Util\Strings::getRandomHex(32);
   }
 }
 
diff --git a/src/Network/FKOAuthDataStore.php b/src/Network/FKOAuthDataStore.php
index 9fba89685..e3ee68d9c 100644
--- a/src/Network/FKOAuthDataStore.php
+++ b/src/Network/FKOAuthDataStore.php
@@ -29,7 +29,7 @@ class FKOAuthDataStore extends OAuthDataStore
 	 */
 	private static function genToken()
 	{
-		return bin2hex(random_bytes(16));
+		return Friendica\Util\Strings::getRandomHex(32);
 	}
 
 	/**

From 3940e804e3ee4ac921e109f62a73fac2becaa611 Mon Sep 17 00:00:00 2001
From: dew-git <55564947+dew-git@users.noreply.github.com>
Date: Thu, 10 Oct 2019 20:48:13 -0800
Subject: [PATCH 3/6] Remove uneeded variable.

---
 src/Module/Login.php | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/Module/Login.php b/src/Module/Login.php
index a8c9f9fb9..8affd7755 100644
--- a/src/Module/Login.php
+++ b/src/Module/Login.php
@@ -190,13 +190,10 @@ class Login extends BaseModule
 					]
 				);
 				if (DBA::isResult($user)) {
-					// Time safe comparision of the two hashes.
-					$validSession = hash_equals(
+					if (!hash_equals(
 						Authentication::getCookieHashForUser($user),
 						$data->hash
-					);
-
-					if (!$validSession) {
+					)) {
 						Logger::log("Hash for user " . $data->uid . " doesn't fit.");
 						Authentication::deleteSession();
 						$a->internalRedirect();

From b5dac16defccaf5a929368b2e7ca6e8c15e40984 Mon Sep 17 00:00:00 2001
From: dew-git <55564947+dew-git@users.noreply.github.com>
Date: Thu, 10 Oct 2019 20:50:51 -0800
Subject: [PATCH 4/6] Comply with coding style.

---
 src/Util/Strings.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Util/Strings.php b/src/Util/Strings.php
index cd065aed1..ef7a2df06 100644
--- a/src/Util/Strings.php
+++ b/src/Util/Strings.php
@@ -68,7 +68,7 @@ class Strings
      */
     public static function escapeHtml($string)
     {
-        return htmlentities($string, ENT_QUOTES | ENT_HTML5, "UTF-8", false);
+        return htmlentities($string, ENT_QUOTES | ENT_HTML5, 'UTF-8', false);
     }
 
     /**

From 1d1c089f84b05312d594ecd052c9a0d8aa942f76 Mon Sep 17 00:00:00 2001
From: dew-git <55564947+dew-git@users.noreply.github.com>
Date: Thu, 10 Oct 2019 21:21:22 -0800
Subject: [PATCH 5/6] Make test comply.

---
 tests/src/Util/StringsTest.php | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tests/src/Util/StringsTest.php b/tests/src/Util/StringsTest.php
index f92618310..03bc88d74 100644
--- a/tests/src/Util/StringsTest.php
+++ b/tests/src/Util/StringsTest.php
@@ -12,7 +12,7 @@ use PHPUnit\Framework\TestCase;
  */
 class StringsTest extends TestCase
 {
-    /**
+	/**
 	 * randomnames should be random, even length
 	 */
 	public function testRandomEven()
@@ -64,9 +64,9 @@ class StringsTest extends TestCase
 
 		$randomname2 = Strings::getRandomName(1);
 		$this->assertEquals(1, strlen($randomname2));
-    }
-    
-    /**
+	}
+
+	/**
 	 * test, that tags are escaped
 	 */
 	public function testEscapeHtml()
@@ -78,7 +78,7 @@ class StringsTest extends TestCase
 
 		$this->assertEquals('[submit type="button" onclick="alert(\'failed!\');" /]', $validstring);
 		$this->assertEquals(
-			"&lt;submit type=&quot;button&quot; onclick=&quot;alert('failed!');&quot; /&gt;",
+			'&lt;submit type&equals;&quot;button&quot; onclick&equals;&quot;alert&lpar;&apos;failed&excl;&apos;&rpar;&semi;&quot; &sol;&gt;',
 			$escapedString
 		);
 	}

From e1e1d26b5beb166af6f747809fbd67eca499ae06 Mon Sep 17 00:00:00 2001
From: dew-git <55564947+dew-git@users.noreply.github.com>
Date: Fri, 11 Oct 2019 00:00:15 -0800
Subject: [PATCH 6/6] Revert random_int changes.

---
 src/Util/Strings.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Util/Strings.php b/src/Util/Strings.php
index ef7a2df06..91b86fbfd 100644
--- a/src/Util/Strings.php
+++ b/src/Util/Strings.php
@@ -86,7 +86,7 @@ class Strings
 
         $vowels = ['a', 'a', 'ai', 'au', 'e', 'e', 'e', 'ee', 'ea', 'i', 'ie', 'o', 'ou', 'u'];
 
-        if (random_int(0, 5) == 4) {
+        if (mt_rand(0, 5) == 4) {
             $vowels[] = 'y';
         }
 
@@ -123,7 +123,7 @@ class Strings
             'kh', 'kl', 'kr', 'mn', 'pl', 'pr', 'rh', 'tr', 'qu', 'wh', 'q'
         ];
 
-        $start = random_int(0, 2);
+        $start = mt_rand(0, 2);
         if ($start == 0) {
             $table = $vowels;
         } else {
@@ -133,7 +133,7 @@ class Strings
         $word = '';
 
         for ($x = 0; $x < $len; $x++) {
-            $r = random_int(0, count($table) - 1);
+            $r = mt_rand(0, count($table) - 1);
             $word .= $table[$r];
 
             if ($table == $vowels) {