Fix legacy mode RAND_RANGE and 32/64-bit consistency

diff --git a/ext/standard/mt_rand.c b/ext/standard/mt_rand.c
index fa7c004b65dd38f33602261961be6f62989be93a..bf9ce66f652b2ae81bcb64d51c49e53073f83bed 100644 (file)
--- a/ext/standard/mt_rand.c
+++ b/ext/standard/mt_rand.c
@@ -217,11 +217,10 @@ PHPAPI zend_long php_mt_rand_range(zend_long min, zend_long max)
        zend_ulong limit;
        zend_ulong result;
 
-#if ZEND_ULONG_MAX > UINT32_MAX
-       result = ((zend_ulong)php_mt_rand() << 32) | php_mt_rand();
-#else
        result = php_mt_rand();
-#endif
+       if (umax > UINT32_MAX) {
+               result = (result << 32) | php_mt_rand();
+       }
 
        /* Special case where no modulus is required */
        if (UNEXPECTED(umax == ZEND_ULONG_MAX)) {
@@ -238,11 +237,7 @@ PHPAPI zend_long php_mt_rand_range(zend_long min, zend_long max)
 
                /* Discard numbers over the limit to avoid modulo bias */
                while (UNEXPECTED(result > limit)) {
-#if ZEND_ULONG_MAX > UINT32_MAX
                        result = (result << 32) | php_mt_rand();
-#else
-                       result = php_mt_rand();
-#endif
                }
        }
 
@@ -256,6 +251,7 @@ PHP_FUNCTION(mt_rand)
 {
        zend_long min;
        zend_long max;
+       zend_long n;
        int argc = ZEND_NUM_ARGS();
 
        if (argc == 0) {
@@ -272,7 +268,15 @@ PHP_FUNCTION(mt_rand)
                RETURN_FALSE;
        }
 
-       RETURN_LONG(php_mt_rand_range(min, max));
+       if (BG(mt_rand_mode) == MT_RAND_MT19937) {
+               RETURN_LONG(php_mt_rand_range(min, max));
+       }
+
+       /* Legacy mode deliberately not inside php_mt_rand_range()
+        * to prevent other functions being affected */
+       n = (zend_long)php_mt_rand() >> 1;
+       RAND_RANGE_BADSCALING(n, min, max, PHP_MT_RAND_MAX);
+       RETURN_LONG(n);
 }
 /* }}} */
 

diff --git a/ext/standard/php_rand.h b/ext/standard/php_rand.h
index 76a368484d2b1715aa481d233f206ce1eaff7eab..506e4976a63cf5ebfaf194dfc96f16df6ccf9846 100644 (file)
--- a/ext/standard/php_rand.h
+++ b/ext/standard/php_rand.h
@@ -60,6 +60,9 @@
  *
  * -RL
  */
+#define RAND_RANGE_BADSCALING(__n, __min, __max, __tmax) \
+       (__n) = (__min) + (zend_long) ((double) ( (double) (__max) - (__min) + 1.0) * ((__n) / ((__tmax) + 1.0)))
+
 #define RAND_RANGE(__n, __min, __max, __tmax) \
        (__n) = php_mt_rand_range((__min), (__max))