From 51b64191e569dd345bf38d3d981fcb28cea8e1f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sat, 30 Mar 2019 14:22:24 +0100
Subject: [PATCH] Fixed slow checking in FwdAnalysis

Credit to OSS-Fuzz for reporting this!
---
 lib/astutils.cpp | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/astutils.cpp b/lib/astutils.cpp
index a05104e8d..428761696 100644
--- a/lib/astutils.cpp
+++ b/lib/astutils.cpp
@@ -1388,11 +1388,14 @@ FwdAnalysis::Result FwdAnalysis::check(const Token *expr, const Token *startToke
     // all variable ids in expr.
     std::set<unsigned int> exprVarIds;
     bool local = true;
+    bool unknownVarId = false;
     visitAstNodes(expr,
     [&](const Token *tok) {
-        if (tok->varId() == 0 && tok->isName() && tok->previous()->str() != ".")
-            // unknown variables are not local
-            local = false;
+        if (tok->varId() == 0 && tok->isName() && tok->previous()->str() != ".") {
+            // unknown variable
+            unknownVarId = true;
+            return ChildrenToVisit::none;
+        }
         if (tok->varId() > 0) {
             exprVarIds.insert(tok->varId());
             if (!Token::simpleMatch(tok->previous(), ".")) {
@@ -1406,6 +1409,9 @@ FwdAnalysis::Result FwdAnalysis::check(const Token *expr, const Token *startToke
         return ChildrenToVisit::op1_and_op2;
     });
 
+    if (unknownVarId)
+        return Result(FwdAnalysis::Result::Type::BAILOUT);
+
     // In unused values checking we do not want to check assignments to
     // global data.
     if (mWhat == What::UnusedValue && isGlobalData(expr))