Add RegExp recursion depth limit (#2543)

The regexp engine does not have any recursion depth check, thus it can cause problems with various regexps. Added a new build option `--regexp-recursion-limit N` whose
default value is 0, which is for unlimited recursion depth. Also added a build-option-test.

Fixes #2448
Fixes #2190

JerryScript-DCO-1.0-Signed-off-by: Istvan Miklos imiklos2@inf.u-szeged.hu

jerry-core/ecma/operations/ecma-regexp-object.h

@@ -28,6 +28,46 @@
  * @{
  */
 
+#ifdef REGEXP_RECURSION_LIMIT
+/**
+ * Decrease the recursion counter and test it.
+ * If the counter reaches the limit of the recursion depth
+ * it will return with a range error.
+ */
+#define REGEXP_RECURSION_COUNTER_DECREASE_AND_TEST() \
+  do \
+  { \
+    if (--re_ctx_p->recursion_counter == 0) \
+    { \
+      return ecma_raise_range_error (ECMA_ERR_MSG ("RegExp recursion limit is exceeded.")); \
+    } \
+  } \
+  while (0)
+/**
+ * Increase the recursion counter.
+ */
+#define REGEXP_RECURSION_COUNTER_INCREASE() (++re_ctx_p->recursion_counter)
+/**
+ * Set the recursion counter to the max depth of the recursion.
+ */
+#define REGEXP_RECURSION_COUNTER_INIT() (re_ctx.recursion_counter = REGEXP_RECURSION_LIMIT)
+#else /* !REGEXP_RECURSION_LIMIT */
+/**
+ * Decrease the recursion counter and test it.
+ * If the counter reaches the limit of the recursion depth
+ * it will return with a range error.
+ */
+#define REGEXP_RECURSION_COUNTER_DECREASE_AND_TEST()
+/**
+ * Increase the recursion counter.
+ */
+#define REGEXP_RECURSION_COUNTER_INCREASE()
+/**
+ * Set the recursion counter to the max depth of the recursion.
+ */
+#define REGEXP_RECURSION_COUNTER_INIT()
+#endif /* REGEXP_RECURSION_LIMIT */
+
 /**
  * RegExp flags
  * Note:
@@ -48,6 +88,9 @@ typedef struct
   const lit_utf8_byte_t **saved_p;      /**< saved result string pointers, ECMA 262 v5, 15.10.2.1, State */
   const lit_utf8_byte_t *input_start_p; /**< start of input pattern string */
   const lit_utf8_byte_t *input_end_p;   /**< end of input pattern string */
+#ifdef REGEXP_RECURSION_LIMIT
+  uint32_t recursion_counter;           /**< RegExp recursion counter */
+#endif /* REGEXP_RECURSION_LIMIT */
   uint32_t num_of_captures;             /**< number of capture groups */
   uint32_t num_of_non_captures;         /**< number of non-capture groups */
   uint32_t *num_of_iterations_p;        /**< number of iterations */