From b0233262b8a4ab3751cf2d94a6966a6ff56461c4 Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Thu, 12 Oct 2017 21:21:52 +0800
Subject: [PATCH] Regex: Limit programs to std::numeric_limits<uint16_t>::max()
 instructions

---
 src/regex_impl.cc | 3 +++
 src/regex_impl.hh | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/regex_impl.cc b/src/regex_impl.cc
index c7c6fe08..2a517d01 100644
--- a/src/regex_impl.cc
+++ b/src/regex_impl.cc
@@ -531,6 +531,9 @@ struct RegexCompiler
     {
         compile_node(m_parsed_regex.ast);
         push_inst(CompiledRegex::Match);
+        constexpr auto max_instructions = std::numeric_limits<uint16_t>::max();
+        if (m_program.instructions.size() >= max_instructions)
+            throw regex_error(format("regex compiled to more than {} instructions", max_instructions));
         m_program.matchers = m_parsed_regex.matchers;
         m_program.save_count = m_parsed_regex.capture_count * 2;
         m_program.direction = direction;
diff --git a/src/regex_impl.hh b/src/regex_impl.hh
index 9a8efdd7..f1068dca 100644
--- a/src/regex_impl.hh
+++ b/src/regex_impl.hh
@@ -235,7 +235,7 @@ private:
     {
         Vector<Thread> current_threads;
         Vector<Thread> next_threads;
-        Vector<uint32_t> processed;
+        Vector<uint16_t> processed;
     };
 
     enum class StepResult { Consumed, Matched, Failed };