Regex: Add a hard limit on the number of nested parenthesis allowed.

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=3471#c2.
This commit is contained in:
jzmaddock
2017-10-19 18:23:43 +01:00
parent b59dc980c8
commit 7de023237f

View File

@ -105,6 +105,7 @@ private:
std::ptrdiff_t m_paren_start; // where the last seen ')' began (where repeats are inserted).
std::ptrdiff_t m_alt_insert_point; // where to insert the next alternative
bool m_has_case_change; // true if somewhere in the current block the case has changed
unsigned m_recursion_count; // How many times we've called parse_all.
#if defined(BOOST_MSVC) && defined(_M_IX86)
// This is an ugly warning suppression workaround (for warnings *inside* std::vector
// that can not otherwise be suppressed)...
@ -120,7 +121,7 @@ private:
template <class charT, class traits>
basic_regex_parser<charT, traits>::basic_regex_parser(regex_data<charT, traits>* data)
: basic_regex_creator<charT, traits>(data), m_mark_count(0), m_mark_reset(-1), m_max_mark(0), m_paren_start(0), m_alt_insert_point(0), m_has_case_change(false)
: basic_regex_creator<charT, traits>(data), m_mark_count(0), m_mark_reset(-1), m_max_mark(0), m_paren_start(0), m_alt_insert_point(0), m_has_case_change(false), m_recursion_count(0)
{
}
@ -245,11 +246,17 @@ void basic_regex_parser<charT, traits>::fail(regex_constants::error_type error_c
template <class charT, class traits>
bool basic_regex_parser<charT, traits>::parse_all()
{
if (++m_recursion_count > 400)
{
// exceeded internal limits
fail(boost::regex_constants::error_complexity, m_position - m_base, "Exceeded nested brace limit.");
}
bool result = true;
while(result && (m_position != m_end))
{
result = (this->*m_parser_proc)();
}
--m_recursion_count;
return result;
}