Changeset 34922

Timestamp:

10/08/2015 12:01:26 AM (11 years ago)

Author:

dd32

Message:

Use PHP7's random_int() CSPRNG functionality in wp_rand() with a fallback to the random_compat library for PHP 5.x.
random_compat offers a set of compatible functions for older versions of PHP, filling in the gap by using other PHP extensions when available.
We still include our existing wp_rand() functionality as a fallback for when no proper CSPRNG exists on the system.

Props sarciszewski
See #28633

Location:

trunk/src/wp-includes

Files:

• compat.php (modified) (1 diff)
• pluggable.php (modified) (3 diffs)
• random_compat (added)
• random_compat/byte_safe_strings.php (added)
• random_compat/error_polyfill.php (added)
• random_compat/random.php (added)
• random_compat/random_bytes_com_dotnet.php (added)
• random_compat/random_bytes_dev_urandom.php (added)
• random_compat/random_bytes_mcrypt.php (added)
• random_compat/random_bytes_openssl.php (added)
• random_compat/random_int.php (added)

trunk/src/wp-includes/compat.php

@@ -333 +333 @@
         }
 }
+
+// random_int was introduced in PHP 7.0
+if ( ! function_exists( 'random_int' ) ) {
+        require ABSPATH . WPINC . '/random_compat/random.php';
+}

trunk/src/wp-includes/pluggable.php

@@ -2133 +2133 @@
  *
  * @since 2.6.2
+ * @since 4.4 Uses PHP7 random_int() or the random_compat library if avaialble.
  *
  * @global string $rnd_value
  * @staticvar string $seed
+ * @staticvar bool $external_rand_source_available
  *
  * @param int $min Lower limit for the generated number
@@ -2143 +2145 @@
 function wp_rand( $min = 0, $max = 0 ) {
         global $rnd_value;
+
+        // Some misconfigured 32bit environments (Entropy PHP, for example) truncate integers larger than PHP_INT_MAX to PHP_INT_MAX rather than overflowing them to floats.
+        $max_random_number = 3000000000 === 2147483647 ? (float) "4294967295" : 4294967295; // 4294967295 = 0xffffffff
+
+        // We only handle Ints, floats are truncated to their integer value.
+        $min = (int) $min;
+        $max = (int) $max;
+
+        // Use PHP's CSPRNG, or a compatible method
+        static $use_random_int_functionality = true;
+        if ( $use_random_int_functionality ) {
+                try {
+                        $_max = ( 0 != $max ) ? $max : $max_random_number;
+                        // wp_rand() can accept arguements in either order, PHP cannot.
+                        $_max = max( $min, $_max );
+                        $_min = min( $min, $_max );
+                        $val = random_int( $_min, $_max );
+                        if ( false !== $val ) {
+                                return absint( $val );
+                        } else {
+                                $use_random_int_functionality = false;
+                        }
+                } catch ( Throwable $t ) { 
+                        $use_random_int_functionality = false;
+                } catch ( Exception $e ) {
+                        $use_random_int_functionality = false;
+                }
+        }
 
         // Reset $rnd_value after 14 uses
@@ -2167 +2197 @@
 
         $value = abs(hexdec($value));
-
-        // Some misconfigured 32bit environments (Entropy PHP, for example) truncate integers larger than PHP_INT_MAX to PHP_INT_MAX rather than overflowing them to floats.
-        $max_random_number = 3000000000 === 2147483647 ? (float) "4294967295" : 4294967295; // 4294967295 = 0xffffffff
 
         // Reduce the value to be within the min - max range