clang/lib/StaticAnalyzer/Checkers/cert/PutenvWithAutoChecker.cpp

   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/CallDescription.h"
  21 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
  22 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
  23 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
  24
  25 using namespace clang;
  26 using namespace ento;
  27
  28 namespace {
  29 class PutenvWithAutoChecker : public Checker<check::PostCall> {
  30 private:
  31   BugType BT{this, "'putenv' function should not be called with auto variables",
  32              categories::SecurityError};
  33   const CallDescription Putenv{{"putenv"}, 1};
  34
  35 public:
  36   void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
  37 };
  38 } // namespace
  39
  40 void PutenvWithAutoChecker::checkPostCall(const CallEvent &Call,
  41                                           CheckerContext &C) const {
  42   if (!Putenv.matches(Call))
  43     return;
  44
  45   SVal ArgV = Call.getArgSVal(0);
  46   const Expr *ArgExpr = Call.getArgExpr(0);
  47   const MemSpaceRegion *MSR = ArgV.getAsRegion()->getMemorySpace();
  48
  49   if (!isa<StackSpaceRegion>(MSR))
  50     return;
  51
  52   StringRef ErrorMsg = "The 'putenv' function should not be called with "
  53                        "arguments that have automatic storage";
  54   ExplodedNode *N = C.generateErrorNode();
  55   auto Report = std::make_unique<PathSensitiveBugReport>(BT, ErrorMsg, N);
  56
  57   // Track the argument.
  58   bugreporter::trackExpressionValue(Report->getErrorNode(), ArgExpr, *Report);
  59
  60   C.emitReport(std::move(Report));
  61 }
  62
  63 void ento::registerPutenvWithAuto(CheckerManager &Mgr) {
  64   Mgr.registerChecker<PutenvWithAutoChecker>();
  65 }
  66
  67 bool ento::shouldRegisterPutenvWithAuto(const CheckerManager &) { return true; }