* use get_random_bytes() for CSRF token

* get_random_bytes: use PHP7 random_bytes() if it is available
* validate CSRF token using hash_equals

include/functions.php

@@ -581,7 +581,7 @@
 
 				$_SESSION["name"] = $row["login"];
 				$_SESSION["access_level"] = $row["access_level"];
-				$_SESSION["csrf_token"] = uniqid_short();
+				$_SESSION["csrf_token"] = bin2hex(get_random_bytes(16));
 
 				$usth = $pdo->prepare("UPDATE ttrss_users SET last_login = NOW() WHERE id = ?");
 				$usth->execute([$user_id]);
@@ -608,9 +608,8 @@
 
 			$_SESSION["auth_module"] = false;
 
-			if (!$_SESSION["csrf_token"]) {
-				$_SESSION["csrf_token"] = uniqid_short();
-			}
+			if (!$_SESSION["csrf_token"])
+				$_SESSION["csrf_token"] = bin2hex(get_random_bytes(16));
 
 			$_SESSION["ip_address"] = $_SERVER["REMOTE_ADDR"];
 
@@ -680,7 +679,7 @@
 	}
 
 	function validate_csrf($csrf_token) {
-		return $csrf_token === $_SESSION['csrf_token'];
+		return hash_equals($csrf_token, $_SESSION['csrf_token']);
 	}
 
 	function load_user_plugins($owner_uid, $pluginhost = false) {
@@ -1669,7 +1668,9 @@
 	}
 
 	function get_random_bytes($length) {
-		if (function_exists('openssl_random_pseudo_bytes')) {
+		if (function_exists('random_bytes')) {
+			return random_bytes($length);
+		} else if (function_exists('openssl_random_pseudo_bytes')) {
 			return openssl_random_pseudo_bytes($length);
 		} else {
 			$output = "";

plugins/af_proxy_http/init.php

@@ -30,7 +30,7 @@ class Af_Proxy_Http extends Plugin {
 		$host->add_hook($host::HOOK_PREFS_TAB, $this);
 
 		if (!$_SESSION['af_proxy_http_token'])
-			$_SESSION['af_proxy_http_token'] = uniqid_short();
+			$_SESSION['af_proxy_http_token'] = bin2hex(get_random_bytes(16));
 	}
 
 	function hook_enclosure_entry($enc) {
@@ -202,7 +202,7 @@ class Af_Proxy_Http extends Plugin {
 	function hook_prefs_tab($args) {
 		if ($args != "prefFeeds") return;
 
-		print "<div dojoType=\"dijit.layout.AccordionPane\" 
+		print "<div dojoType=\"dijit.layout.AccordionPane\"
 			title=\"<i class='material-icons'>extension</i> ".__('Image proxy settings (af_proxy_http)')."\">";
 
 		print "<form dojoType=\"dijit.form.Form\">";