1 //== PutenvWithAutoChecker.cpp --------------------------------- -*- C++ -*--=// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file defines PutenvWithAutoChecker which finds calls of ``putenv`` 10 // function with automatic variable as the argument. 11 // https://wiki.sei.cmu.edu/confluence/x/6NYxBQ 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "../AllocationState.h" 16 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h" 17 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 18 #include "clang/StaticAnalyzer/Core/Checker.h" 19 #include "clang/StaticAnalyzer/Core/CheckerManager.h" 20 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" 21 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 22 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h" 23 24 using namespace clang; 25 using namespace ento; 26 27 namespace { 28 class PutenvWithAutoChecker : public Checker<check::PostCall> { 29 private: 30 BugType BT{this, "'putenv' function should not be called with auto variables", 31 categories::SecurityError}; 32 const CallDescription Putenv{"putenv", 1}; 33 34 public: 35 void checkPostCall(const CallEvent &Call, CheckerContext &C) const; 36 }; 37 } // namespace 38 39 void PutenvWithAutoChecker::checkPostCall(const CallEvent &Call, 40 CheckerContext &C) const { 41 if (!Call.isCalled(Putenv)) 42 return; 43 44 SVal ArgV = Call.getArgSVal(0); 45 const Expr *ArgExpr = Call.getArgExpr(0); 46 const MemSpaceRegion *MSR = ArgV.getAsRegion()->getMemorySpace(); 47 48 if (!isa<StackSpaceRegion>(MSR)) 49 return; 50 51 StringRef ErrorMsg = "The 'putenv' function should not be called with " 52 "arguments that have automatic storage"; 53 ExplodedNode *N = C.generateErrorNode(); 54 auto Report = std::make_unique<PathSensitiveBugReport>(BT, ErrorMsg, N); 55 56 // Track the argument. 57 bugreporter::trackExpressionValue(Report->getErrorNode(), ArgExpr, *Report); 58 59 C.emitReport(std::move(Report)); 60 } 61 62 void ento::registerPutenvWithAuto(CheckerManager &Mgr) { 63 Mgr.registerChecker<PutenvWithAutoChecker>(); 64 } 65 66 bool ento::shouldRegisterPutenvWithAuto(const CheckerManager &) { return true; } 67