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//== PutenvStackArrayChecker.cpp ------------------------------- -*- C++ -*--=//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines PutenvStackArrayChecker which finds calls of ``putenv``
// function with automatic array variable as the argument.
// https://wiki.sei.cmu.edu/confluence/x/6NYxBQ
//
//===----------------------------------------------------------------------===//
#include "AllocationState.h"
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
using namespace clang;
using namespace ento;
namespace {
class PutenvStackArrayChecker : public Checker<check::PostCall> {
private:
BugType BT{this, "'putenv' called with stack-allocated string",
categories::SecurityError};
const CallDescription Putenv{CDM::CLibrary, {"putenv"}, 1};
public:
void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
};
} // namespace
void PutenvStackArrayChecker::checkPostCall(const CallEvent &Call,
CheckerContext &C) const {
if (!Putenv.matches(Call))
return;
SVal ArgV = Call.getArgSVal(0);
const Expr *ArgExpr = Call.getArgExpr(0);
const auto *SSR =
dyn_cast<StackSpaceRegion>(ArgV.getAsRegion()->getMemorySpace());
if (!SSR)
return;
const auto *StackFrameFuncD =
dyn_cast_or_null<FunctionDecl>(SSR->getStackFrame()->getDecl());
if (StackFrameFuncD && StackFrameFuncD->isMain())
return;
StringRef ErrorMsg = "The 'putenv' function should not be called with "
"arrays that have automatic storage";
ExplodedNode *N = C.generateErrorNode();
auto Report = std::make_unique<PathSensitiveBugReport>(BT, ErrorMsg, N);
// Track the argument.
bugreporter::trackExpressionValue(Report->getErrorNode(), ArgExpr, *Report);
C.emitReport(std::move(Report));
}
void ento::registerPutenvStackArray(CheckerManager &Mgr) {
Mgr.registerChecker<PutenvStackArrayChecker>();
}
bool ento::shouldRegisterPutenvStackArray(const CheckerManager &) {
return true;
}
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