commit d39d21db47a4f1f4e9d3b906564e4eaca9262660
author Marshall Clow <mclow.lists@gmail.com> Tue Sep 12 17:56:59 2017 +0000
committer Marshall Clow <mclow.lists@gmail.com> Tue Sep 12 17:56:59 2017 +0000
tree 7d540ca1c146c2abc3cc0ead821c17ef667f8128
parent 33932625e4f031d0c624b0382170b87c9d691ad1

Apply D28224: 'Throw exception after too many steps' Fixes PR#20291. Thanks to Tim Shen for the patch

llvm-svn: 313056
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 5a72679338f9dc0e38c98befe65aac73de1822ab

include/regex

diff --git a/include/regex b/include/regex
index 77ca648..dfc97c5 100644
--- a/include/regex
+++ b/include/regex
@@ -773,6 +773,8 @@
 #include <__undef_macros>
 
 
+#define _LIBCPP_REGEX_COMPLEXITY_FACTOR 4096
+
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 namespace regex_constants
@@ -5552,8 +5554,14 @@
         __states.back().__node_ = __st;
         __states.back().__flags_ = __flags;
         __states.back().__at_first_ = __at_first;
+        int __counter = 0;
+        int __length = __last - __first;
         do
         {
+            ++__counter;
+            if (__counter % _LIBCPP_REGEX_COMPLEXITY_FACTOR == 0 &&
+                __counter / _LIBCPP_REGEX_COMPLEXITY_FACTOR >= __length)
+              __throw_regex_error<regex_constants::error_complexity>();
             __state& __s = __states.back();
             if (__s.__node_)
                 __s.__node_->__exec(__s);
@@ -5627,8 +5635,14 @@
         __states.back().__flags_ = __flags;
         __states.back().__at_first_ = __at_first;
         bool __matched = false;
+        int __counter = 0;
+        int __length = __last - __first;
         do
         {
+            ++__counter;
+            if (__counter % _LIBCPP_REGEX_COMPLEXITY_FACTOR == 0 &&
+                __counter / _LIBCPP_REGEX_COMPLEXITY_FACTOR >= __length)
+              __throw_regex_error<regex_constants::error_complexity>();
             __state& __s = __states.back();
             if (__s.__node_)
                 __s.__node_->__exec(__s);
@@ -5724,8 +5738,14 @@
         __states.back().__at_first_ = __at_first;
         const _CharT* __current = __first;
         bool __matched = false;
+        int __counter = 0;
+        int __length = __last - __first;
         do
         {
+            ++__counter;
+            if (__counter % _LIBCPP_REGEX_COMPLEXITY_FACTOR == 0 &&
+                __counter / _LIBCPP_REGEX_COMPLEXITY_FACTOR >= __length)
+              __throw_regex_error<regex_constants::error_complexity>();
             __state& __s = __states.back();
             if (__s.__node_)
                 __s.__node_->__exec(__s);