Avoid Full Path Disclosure error on session error.

[github/shaarli/Shaarli.git] / application / Utils.php

diff --git a/application/Utils.php b/application/Utils.php
index 737f150253d407f07d55d2411a6f4fad4558ed41..fa18f1588b278352554dbf85312980f4be6289e8 100644 (file)
--- a/application/Utils.php
+++ b/application/Utils.php
@@ -42,4 +42,123 @@ function endsWith($haystack, $needle, $case=true)
     }
     return (strcasecmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
 }
-?>
+
+/**
+ * Same as nl2br(), but escapes < and >
+ */
+function nl2br_escaped($html)
+{
+    return str_replace('>', '&gt;', str_replace('<', '&lt;', nl2br($html)));
+}
+
+/**
+ * htmlspecialchars wrapper
+ */
+function escape($str)
+{
+    return htmlspecialchars($str, ENT_COMPAT, 'UTF-8', false);
+}
+
+/**
+ * Link sanitization before templating
+ */
+function sanitizeLink(&$link)
+{
+    $link['url'] = escape($link['url']); // useful?
+    $link['title'] = escape($link['title']);
+    $link['description'] = escape($link['description']);
+    $link['tags'] = escape($link['tags']);
+}
+
+/**
+ * Checks if a string represents a valid date
+ *
+ * @param string        a string-formatted date
+ * @param format        the expected DateTime format of the string
+ * @return              whether the string is a valid date
+ * @see                 http://php.net/manual/en/class.datetime.php
+ * @see                 http://php.net/manual/en/datetime.createfromformat.php
+ */
+function checkDateFormat($format, $string)
+{
+    $date = DateTime::createFromFormat($format, $string);
+    return $date && $date->format($string) == $string;
+}
+
+/**
+ * Generate a header location from HTTP_REFERER.
+ * Make sure the referer is Shaarli itself and prevent redirection loop.
+ *
+ * @param string $referer - HTTP_REFERER.
+ * @param string $host - Server HOST.
+ * @param array $loopTerms - Contains list of term to prevent redirection loop.
+ *
+ * @return string $referer - final referer.
+ */
+function generateLocation($referer, $host, $loopTerms = array())
+{
+    $final_referer = '?';
+
+    // No referer if it contains any value in $loopCriteria.
+    foreach ($loopTerms as $value) {
+        if (strpos($referer, $value) !== false) {
+            return $final_referer;
+        }
+    }
+
+    // Remove port from HTTP_HOST
+    if ($pos = strpos($host, ':')) {
+        $host = substr($host, 0, $pos);
+    }
+
+    if (!empty($referer) && strpos(parse_url($referer, PHP_URL_HOST), $host) !== false) {
+        $final_referer = $referer;
+    }
+
+    return $final_referer;
+}
+
+/**
+ * Checks the PHP version to ensure Shaarli can run
+ *
+ * @param string $minVersion minimum PHP required version
+ * @param string $curVersion current PHP version (use PHP_VERSION)
+ *
+ * @throws Exception    the PHP version is not supported
+ */
+function checkPHPVersion($minVersion, $curVersion)
+{
+    if (version_compare($curVersion, $minVersion) < 0) {
+        throw new Exception(
+            'Your PHP version is obsolete!'
+            .' Shaarli requires at least PHP '.$minVersion.', and thus cannot run.'
+            .' Your PHP version has known security vulnerabilities and should be'
+            .' updated as soon as possible.'
+        );
+    }
+}
+
+/**
+ * Validate session ID to prevent Full Path Disclosure.
+ * See #298.
+ *
+ * @param string $sessionId Session ID
+ *
+ * @return true if valid, false otherwise.
+ */
+function is_session_id_valid($sessionId)
+{
+    if (empty($sessionId)) {
+        return false;
+    }
+
+    if (!$sessionId) {
+        return false;
+    }
+
+    if (!preg_match('/^[a-z0-9]{2,32}$/', $sessionId)) {
+        return false;
+    }
+
+    return true;
+}