Set a limit on max recursions.

Applies to last remaining recursive calls in regex creation, and format string parsing.
Added tests, and updated CI.
This commit is contained in:
jzmaddock
2024-03-16 19:06:10 +00:00
parent 237e69caf6
commit b86985e65a
9 changed files with 146 additions and 171 deletions

View File

@ -248,7 +248,7 @@ private:
void fixup_recursions(re_syntax_base* state);
void create_startmaps(re_syntax_base* state);
int calculate_backstep(re_syntax_base* state);
void create_startmap(re_syntax_base* state, unsigned char* l_map, unsigned int* pnull, unsigned char mask);
void create_startmap(re_syntax_base* state, unsigned char* l_map, unsigned int* pnull, unsigned char mask, unsigned recursion_count = 0);
unsigned get_restart_type(re_syntax_base* state);
void set_all_masks(unsigned char* bits, unsigned char);
bool is_bad_repeat(re_syntax_base* pt);
@ -1074,7 +1074,7 @@ struct recursion_saver
};
template <class charT, class traits>
void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state, unsigned char* l_map, unsigned int* pnull, unsigned char mask)
void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state, unsigned char* l_map, unsigned int* pnull, unsigned char mask, unsigned recursion_count)
{
recursion_saver saved_recursions(&m_recursion_checks);
int not_last_jump = 1;
@ -1085,6 +1085,28 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
// track case sensitivity:
bool l_icase = m_icase;
if (recursion_count > BOOST_REGEX_MAX_RECURSION_DEPTH)
{
// Oops error:
if (0 == this->m_pdata->m_status) // update the error code if not already set
this->m_pdata->m_status = boost::regex_constants::error_complexity;
//
// clear the expression, we should be empty:
//
this->m_pdata->m_expression = 0;
this->m_pdata->m_expression_len = 0;
//
// and throw if required:
//
if (0 == (this->flags() & regex_constants::no_except))
{
std::string message = "Expression complexity exceeded.";
boost::regex_error e(message, boost::regex_constants::error_complexity, 0);
e.raise();
}
return;
}
while(state)
{
switch(state->type)
@ -1122,7 +1144,7 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
}
// now figure out if we can match a NULL string at this point:
if(pnull)
create_startmap(state->next.p, 0, pnull, mask);
create_startmap(state->next.p, 0, pnull, mask, ++recursion_count);
return;
}
case syntax_element_recurse:
@ -1184,7 +1206,7 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
case syntax_element_word_start:
{
// recurse, then AND with all the word characters:
create_startmap(state->next.p, l_map, pnull, mask);
create_startmap(state->next.p, l_map, pnull, mask, ++recursion_count);
if(l_map)
{
l_map[0] |= mask_init;
@ -1199,7 +1221,7 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
case syntax_element_word_end:
{
// recurse, then AND with all the word characters:
create_startmap(state->next.p, l_map, pnull, mask);
create_startmap(state->next.p, l_map, pnull, mask, ++recursion_count);
if(l_map)
{
l_map[0] |= mask_init;
@ -1291,11 +1313,11 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
return;
}
set_bad_repeat(state);
create_startmap(state->next.p, l_map, pnull, mask);
create_startmap(state->next.p, l_map, pnull, mask, ++recursion_count);
if((state->type == syntax_element_alt)
|| (static_cast<re_repeat*>(state)->min == 0)
|| (not_last_jump == 0))
create_startmap(rep->alt.p, l_map, pnull, mask);
create_startmap(rep->alt.p, l_map, pnull, mask, ++recursion_count);
}
}
return;
@ -1354,7 +1376,7 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
if(ok && ((m_recursion_checks[static_cast<re_brace*>(state)->index] & 2u) == 0))
{
m_recursion_checks[static_cast<re_brace*>(state)->index] |= 2u;
create_startmap(p->next.p, l_map, pnull, mask);
create_startmap(p->next.p, l_map, pnull, mask, ++recursion_count);
}
}
state = state->next.p;