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C++ regex parse tree and RegexTreeViewSig implementation (Phase 1 of ReDoS support)#22200
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[WIP] Add C++ regular-expression parse tree foundation
C++ regex parse tree and RegexTreeViewSig implementation (Phase 1 of ReDoS support)
Jul 15, 2026
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jketema due to an error
July 16, 2026 13:10
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| import cpp | ||
| private import semmle.code.cpp.dataflow.new.DataFlow |
| private import cpp | ||
| private import semmle.code.cpp.regex.RegexTreeView::RegexTreeView as TreeView | ||
| import codeql.regex.nfa.SuperlinearBackTracking::Make<TreeView> as SuperlinearBackTracking | ||
| private import semmle.code.cpp.ir.dataflow.DataFlow |
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| // Instantiate the shared analysis modules with our RegexTreeView. | ||
| // If RegexTreeView does not satisfy RegexTreeViewSig, these lines cause a compile error. | ||
| private module TestSuperlinear = SuperlinearBackTracking::Make<RegexTreeView>; |
| // If RegexTreeView does not satisfy RegexTreeViewSig, these lines cause a compile error. | ||
| private module TestSuperlinear = SuperlinearBackTracking::Make<RegexTreeView>; | ||
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| private module TestNfaUtils = NfaUtils::Make<RegexTreeView>; |
| @@ -0,0 +1 @@ | |||
| query: Security/CWE/CWE-1333/ReDoS.ql | |||
| @@ -0,0 +1 @@ | |||
| query: Security/CWE/CWE-1333/PolynomialReDoS.ql | |||
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C++ (
codeql/cpp-all) has no regex parse tree and noRegexTreeViewSigimplementation, blocking instantiation of the sharedcodeql/regexReDoS engines. This PR adds the self-contained foundation — parser + tree view — with no queries and no dataflow (Phase 2).New:
ParseRegExp.qllcpp/ql/lib/semmle/code/cpp/regex/internal/ParseRegExp.qllclass RegExp extends StringLiteralproviding offset-span predicates for the full ECMAScript construct set:*,+,?,{n},{n,m},{n,}(greedy and lazy)(...),(?:...),(?<name>...),(?=...),(?!...),(?<=...),(?<!...).,^,$,\b,\B)\1and ECMAScript named\k<name>\n,\r,\t,\xhh,\uhhhh,\u{...}, identity escapesECMAScript semantics throughout (targeting
std::regex's default mode). Phase 1 conservatively treats allStringLiterals as candidate regexes; Phase 2 will restrict viastd::regexconstruction-site dataflow.New:
RegexTreeView.qllcpp/ql/lib/semmle/code/cpp/regex/RegexTreeView.qllprivate newtype TRegExpParentwith 9 variants +module Impl implements RegexTreeViewSig:RegExpQuantifier/RegExpStar/RegExpPlus/RegExpOpt/RegExpRange,RegExpAlt,RegExpSequence,RegExpGroup,RegExpCharacterClass/RegExpCharacterRange,RegExpNormalChar/RegExpEscape/RegExpCharacterClassEscape,RegExpSpecialChar,RegExpDot/RegExpAnchor/RegExpCaret/RegExpDollar/RegExpWordBoundary/RegExpNonWordBoundary,RegExpSubPattern/lookahead/lookbehind variants,RegExpBackRef,RegExpConstantisPossessive → none(),matchesAnyPrefix/AnySuffix → any(),isIgnoreCase/isDotAll → none()(conservative; TODO for Phase 2 construction-site flag detection)hasLocationInfomaps term offsets back to source columns within the enclosingStringLiteralimport Impl as RegexTreeView(functor argument) andimport Impl(direct use)Compile check
cpp/ql/test/library-tests/regex/CompileCheck.qlinstantiates bothSuperlinearBackTracking::Make<RegexTreeView>andNfaUtils::Make<RegexTreeView>to verify the signature is satisfied end-to-end.Tests
cpp/ql/test/library-tests/regex/— test source covering quantifiers, nested quantifiers (relevant for ReDoS:(a+)+), named groups, lookahead/lookbehind, backreferences, anchors, character classes; plus parse-tree printer (parse.ql), table query (regexp.ql), andfailedToParseconsistency check (Consistency.ql).Packaging
cpp/ql/lib/qlpack.yml— addscodeql/regex: ${workspace}dependency.