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de-fuzz: fix infinite recursion when analysing tail-recursive expressions.

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jzmaddock
2017-02-16 19:24:22 +00:00
parent 7f89a8f3b8
commit d70b7bcefe
1 changed files with 11 additions and 12 deletions
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23
include/boost/regex/v4/basic_regex_creator.hpp
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@ -240,7 +240,7 @@ protected:
unsigned m_backrefs; // bitmask of permitted backrefs unsigned m_backrefs; // bitmask of permitted backrefs
boost::uintmax_t m_bad_repeats; // bitmask of repeats we can't deduce a startmap for; boost::uintmax_t m_bad_repeats; // bitmask of repeats we can't deduce a startmap for;
bool m_has_recursions; // set when we have recursive expresisons to fixup bool m_has_recursions; // set when we have recursive expresisons to fixup
std::vector<bool> m_recursion_checks; // notes which recursions we've followed while analysing this expression std::vector<unsigned char> m_recursion_checks; // notes which recursions we've followed while analysing this expression
typename traits::char_class_type m_word_mask; // mask used to determine if a character is a word character typename traits::char_class_type m_word_mask; // mask used to determine if a character is a word character
typename traits::char_class_type m_mask_space; // mask used to determine if a character is a word character typename traits::char_class_type m_mask_space; // mask used to determine if a character is a word character
typename traits::char_class_type m_lower_mask; // mask used to determine if a character is a lowercase character typename traits::char_class_type m_lower_mask; // mask used to determine if a character is a lowercase character
@ -699,7 +699,7 @@ void basic_regex_creator<charT, traits>::finalize(const charT* p1, const charT*
m_bad_repeats = 0; m_bad_repeats = 0;
if(m_has_recursions) if(m_has_recursions)
m_recursion_checks.assign(1 + m_pdata->m_mark_count, false); m_recursion_checks.assign(1 + m_pdata->m_mark_count, 0u);
create_startmap(m_pdata->m_first_state, m_pdata->m_startmap, &(m_pdata->m_can_be_null), mask_all); create_startmap(m_pdata->m_first_state, m_pdata->m_startmap, &(m_pdata->m_can_be_null), mask_all);
// get the restart type: // get the restart type:
m_pdata->m_restart_type = get_restart_type(m_pdata->m_first_state); m_pdata->m_restart_type = get_restart_type(m_pdata->m_first_state);
@ -943,7 +943,7 @@ void basic_regex_creator<charT, traits>::create_startmaps(re_syntax_base* state)
{ {
// Initialize m_recursion_checks if we need it: // Initialize m_recursion_checks if we need it:
if(m_has_recursions) if(m_has_recursions)
m_recursion_checks.assign(1 + m_pdata->m_mark_count, false); m_recursion_checks.assign(1 + m_pdata->m_mark_count, 0u);
const std::pair<bool, re_syntax_base*>& p = v.back(); const std::pair<bool, re_syntax_base*>& p = v.back();
m_icase = p.first; m_icase = p.first;
@ -956,7 +956,7 @@ void basic_regex_creator<charT, traits>::create_startmaps(re_syntax_base* state)
m_bad_repeats = 0; m_bad_repeats = 0;
if(m_has_recursions) if(m_has_recursions)
m_recursion_checks.assign(1 + m_pdata->m_mark_count, false); m_recursion_checks.assign(1 + m_pdata->m_mark_count, 0u);
create_startmap(static_cast<re_alt*>(state)->alt.p, static_cast<re_alt*>(state)->_map, &static_cast<re_alt*>(state)->can_be_null, mask_skip); create_startmap(static_cast<re_alt*>(state)->alt.p, static_cast<re_alt*>(state)->_map, &static_cast<re_alt*>(state)->can_be_null, mask_skip);
// adjust the type of the state to allow for faster matching: // adjust the type of the state to allow for faster matching:
state->type = this->get_repeat_type(state); state->type = this->get_repeat_type(state);
@ -1111,11 +1111,9 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
} }
case syntax_element_recurse: case syntax_element_recurse:
{ {
if(state->type == syntax_element_startmark) BOOST_ASSERT(static_cast<const re_jump*>(state)->alt.p->type == syntax_element_startmark);
recursion_sub = static_cast<re_brace*>(state)->index; recursion_sub = static_cast<re_brace*>(static_cast<const re_jump*>(state)->alt.p)->index;
else if(m_recursion_checks[recursion_sub] & 1u)
recursion_sub = 0;
if(m_recursion_checks[recursion_sub])
{ {
// Infinite recursion!! // Infinite recursion!!
if(0 == this->m_pdata->m_status) // update the error code if not already set if(0 == this->m_pdata->m_status) // update the error code if not already set
@ -1140,10 +1138,10 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
recursion_start = state; recursion_start = state;
recursion_restart = state->next.p; recursion_restart = state->next.p;
state = static_cast<re_jump*>(state)->alt.p; state = static_cast<re_jump*>(state)->alt.p;
m_recursion_checks[recursion_sub] = true; m_recursion_checks[recursion_sub] |= 1u;
break; break;
} }
m_recursion_checks[recursion_sub] = true; m_recursion_checks[recursion_sub] |= 1u;
// can't handle nested recursion here... // can't handle nested recursion here...
BOOST_FALLTHROUGH; BOOST_FALLTHROUGH;
} }
@ -1337,8 +1335,9 @@ void basic_regex_creator<charT, traits>::create_startmap(re_syntax_base* state,
} }
p = p->next.p; p = p->next.p;
} }
if(ok) 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);
} }
} }