Regex: Set a limit on how many recursions we allow.

This commit is contained in:
jzmaddock
2017-11-09 11:23:54 +00:00
parent 9f104b0664
commit 6246f5ec51
2 changed files with 22 additions and 4 deletions

View File

@ -378,7 +378,7 @@ public:
BidiIterator l_base)
: m_result(what), base(first), last(end),
position(first), backstop(l_base), re(e), traits_inst(e.get_traits()),
m_independent(false), next_count(&rep_obj), rep_obj(&next_count)
m_independent(false), next_count(&rep_obj), rep_obj(&next_count), m_recursions(0)
{
construct_init(e, f);
}
@ -566,6 +566,8 @@ private:
bool m_unwound_alt;
// We are unwinding a commit - used by independent subs to determine whether to stop there or carry on unwinding:
//bool m_unwind_commit;
// Recursion limit:
unsigned m_recursions;
#endif
// these operations aren't allowed, so are declared private,

View File

@ -143,6 +143,15 @@ struct saved_change_case : public saved_state
saved_change_case(bool c) : saved_state(18), icase(c) {}
};
struct incrementer
{
incrementer(unsigned* pu) : m_pu(pu) { ++*m_pu; }
~incrementer() { --*m_pu; }
bool operator > (unsigned i) { return *m_pu > i; }
private:
unsigned* m_pu;
};
template <class BidiIterator, class Allocator, class traits>
bool perl_matcher<BidiIterator, Allocator, traits>::match_all_states()
{
@ -187,7 +196,9 @@ bool perl_matcher<BidiIterator, Allocator, traits>::match_all_states()
&perl_matcher<BidiIterator, Allocator, traits>::match_commit,
&perl_matcher<BidiIterator, Allocator, traits>::match_then,
};
incrementer inc(&m_recursions);
if(inc > 80)
raise_error(traits_inst, regex_constants::error_complexity);
push_recursion_stopper();
do{
while(pstate)
@ -1762,8 +1773,11 @@ bool perl_matcher<BidiIterator, Allocator, traits>::unwind_non_greedy_repeat(boo
template <class BidiIterator, class Allocator, class traits>
bool perl_matcher<BidiIterator, Allocator, traits>::unwind_recursion(bool r)
{
// We are backtracking back inside a recursion, need to push the info
// back onto the recursion stack, and do so unconditionally, otherwise
// we can get mismatched pushes and pops...
saved_recursion<results_type>* pmp = static_cast<saved_recursion<results_type>*>(m_backup_state);
if(!r)
if (!r)
{
recursion_stack.push_back(recursion_info<results_type>());
recursion_stack.back().idx = pmp->recursion_id;
@ -1780,8 +1794,10 @@ bool perl_matcher<BidiIterator, Allocator, traits>::unwind_recursion(bool r)
template <class BidiIterator, class Allocator, class traits>
bool perl_matcher<BidiIterator, Allocator, traits>::unwind_recursion_pop(bool r)
{
// Backtracking out of a recursion, we must pop state off the recursion
// stack unconditionally to ensure matched pushes and pops:
saved_state* pmp = static_cast<saved_state*>(m_backup_state);
if(!r)
if (!r)
{
*m_presult = recursion_stack.back().results;
position = recursion_stack.back().location_of_start;