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
checkPostCall(const CallEvent & Call,CheckerContext & C) const39 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
registerPutenvWithAuto(CheckerManager & Mgr)62 void ento::registerPutenvWithAuto(CheckerManager &Mgr) {
63 Mgr.registerChecker<PutenvWithAutoChecker>();
64 }
65
shouldRegisterPutenvWithAuto(const CheckerManager &)66 bool ento::shouldRegisterPutenvWithAuto(const CheckerManager &) { return true; }
67