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LibRegex: Make parse_disjunction() consume all disjunctions in one frame

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This helps us not blow up when too many disjunctions are chained togther
in the regex we're parsing.
Fixes #12615.
This commit is contained in:
Ali Mohammad Pur 2022-02-19 17:34:55 +03:30 • committed by Andreas Kling
parent 627bbee055
commit 4be7239626
2 changed files with 33 additions and 21 deletions
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47
Userland/Libraries/LibRegex/RegexParser.cpp
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@ -956,28 +956,37 @@ bool ECMA262Parser::parse_pattern(ByteCode& stack, size_t& match_length_minimum,
bool ECMA262Parser::parse_disjunction(ByteCode& stack, size_t& match_length_minimum, bool unicode, bool named)
{
ByteCode left_alternative_stack;
size_t left_alternative_min_length = 0;
auto alt_ok = parse_alternative(left_alternative_stack, left_alternative_min_length, unicode, named);
if (!alt_ok)
return false;
size_t total_match_length_minimum = NumericLimits<size_t>::max();
Vector<ByteCode> alternatives;
do {
ByteCode alternative_stack;
size_t alternative_minimum_length = 0;
auto alt_ok = parse_alternative(alternative_stack, alternative_minimum_length, unicode, named);
if (!alt_ok)
return false;
if (!match(TokenType::Pipe)) {
stack.extend(left_alternative_stack);
match_length_minimum = left_alternative_min_length;
return alt_ok;
alternatives.append(move(alternative_stack));
total_match_length_minimum = min(alternative_minimum_length, total_match_length_minimum);
if (!match(TokenType::Pipe))
break;
consume();
} while (true);
Optional<ByteCode> alternative_stack {};
for (auto& alternative : alternatives) {
if (alternative_stack.has_value()) {
ByteCode target_stack;
target_stack.insert_bytecode_alternation(alternative_stack.release_value(), move(alternative));
alternative_stack = move(target_stack);
} else {
alternative_stack = move(alternative);
}
}
consume();
ByteCode right_alternative_stack;
size_t right_alternative_min_length = 0;
auto continuation_ok = parse_disjunction(right_alternative_stack, right_alternative_min_length, unicode, named);
if (!continuation_ok)
return false;
stack.insert_bytecode_alternation(move(left_alternative_stack), move(right_alternative_stack));
match_length_minimum = min(left_alternative_min_length, right_alternative_min_length);
return continuation_ok;
stack.extend(alternative_stack.release_value());
match_length_minimum = total_match_length_minimum;
return true;
}
bool ECMA262Parser::parse_alternative(ByteCode& stack, size_t& match_length_minimum, bool unicode, bool named)