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
24using namespace clang;
25using namespace ento;
26
27namespace {
28class PutenvWithAutoChecker : public Checker<check::PostCall> {
29private:
30  BugType BT{this, "'putenv' function should not be called with auto variables",
31             categories::SecurityError};
32  const CallDescription Putenv{"putenv", 1};
33
34public:
35  void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
36};
37} // namespace
38
39void 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
62void ento::registerPutenvWithAuto(CheckerManager &Mgr) {
63  Mgr.registerChecker<PutenvWithAutoChecker>();
64}
65
66bool ento::shouldRegisterPutenvWithAuto(const CheckerManager &) { return true; }
67