From b65bf1b459be3cef19dcd8edbce59fc1d8799247 Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Tue, 21 Feb 2017 19:38:36 +0000
Subject: [PATCH] de-fuzz: make sure recursion stack always has a valid start
 location for the recursion.

---
 include/boost/regex/v4/perl_matcher_non_recursive.hpp | 1 +
 include/boost/regex/v4/perl_matcher_recursive.hpp     | 1 +
 2 files changed, 2 insertions(+)

diff --git a/include/boost/regex/v4/perl_matcher_non_recursive.hpp b/include/boost/regex/v4/perl_matcher_non_recursive.hpp
index 6af90fb7..88bceed3 100644
--- a/include/boost/regex/v4/perl_matcher_non_recursive.hpp
+++ b/include/boost/regex/v4/perl_matcher_non_recursive.hpp
@@ -1719,6 +1719,7 @@ bool perl_matcher<BidiIterator, Allocator, traits>::unwind_recursion(bool r)
       recursion_stack.back().idx = pmp->recursion_id;
       recursion_stack.back().preturn_address = pmp->preturn_address;
       recursion_stack.back().results = pmp->results;
+      recursion_stack.back().location_of_start = position;
    }
    boost::BOOST_REGEX_DETAIL_NS::inplace_destroy(pmp++);
    m_backup_state = pmp;
diff --git a/include/boost/regex/v4/perl_matcher_recursive.hpp b/include/boost/regex/v4/perl_matcher_recursive.hpp
index 023e62dd..7cc54ca2 100644
--- a/include/boost/regex/v4/perl_matcher_recursive.hpp
+++ b/include/boost/regex/v4/perl_matcher_recursive.hpp
@@ -996,6 +996,7 @@ bool perl_matcher<BidiIterator, Allocator, traits>::match_match()
          recursion_stack.push_back(recursion_info<results_type>());
          recursion_stack.back().preturn_address = saved_state;
          recursion_stack.back().results = *m_presult;
+         recursion_stack.back().location_of_start = position;
          return false;
       }
       return true;