98 lines
3.2 KiB
C++
98 lines
3.2 KiB
C++
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//== ArrayBoundChecker.cpp ------------------------------*- C++ -*--==//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines ArrayBoundChecker, which is a path-sensitive check
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// which looks for an out-of-bound array element access.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
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#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
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#include "clang/StaticAnalyzer/Core/Checker.h"
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#include "clang/StaticAnalyzer/Core/CheckerManager.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/DynamicSize.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
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using namespace clang;
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using namespace ento;
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namespace {
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class ArrayBoundChecker :
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public Checker<check::Location> {
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mutable std::unique_ptr<BuiltinBug> BT;
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public:
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void checkLocation(SVal l, bool isLoad, const Stmt* S,
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CheckerContext &C) const;
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};
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}
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void ArrayBoundChecker::checkLocation(SVal l, bool isLoad, const Stmt* LoadS,
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CheckerContext &C) const {
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// Check for out of bound array element access.
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const MemRegion *R = l.getAsRegion();
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if (!R)
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return;
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const ElementRegion *ER = dyn_cast<ElementRegion>(R);
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if (!ER)
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return;
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// Get the index of the accessed element.
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DefinedOrUnknownSVal Idx = ER->getIndex().castAs<DefinedOrUnknownSVal>();
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// Zero index is always in bound, this also passes ElementRegions created for
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// pointer casts.
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if (Idx.isZeroConstant())
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return;
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ProgramStateRef state = C.getState();
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// Get the size of the array.
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DefinedOrUnknownSVal ElementCount = getDynamicElementCount(
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state, ER->getSuperRegion(), C.getSValBuilder(), ER->getValueType());
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ProgramStateRef StInBound = state->assumeInBound(Idx, ElementCount, true);
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ProgramStateRef StOutBound = state->assumeInBound(Idx, ElementCount, false);
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if (StOutBound && !StInBound) {
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ExplodedNode *N = C.generateErrorNode(StOutBound);
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if (!N)
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return;
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if (!BT)
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BT.reset(new BuiltinBug(
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this, "Out-of-bound array access",
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"Access out-of-bound array element (buffer overflow)"));
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// FIXME: It would be nice to eventually make this diagnostic more clear,
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// e.g., by referencing the original declaration or by saying *why* this
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// reference is outside the range.
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// Generate a report for this bug.
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auto report =
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std::make_unique<PathSensitiveBugReport>(*BT, BT->getDescription(), N);
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report->addRange(LoadS->getSourceRange());
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C.emitReport(std::move(report));
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return;
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}
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// Array bound check succeeded. From this point forward the array bound
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// should always succeed.
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C.addTransition(StInBound);
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}
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void ento::registerArrayBoundChecker(CheckerManager &mgr) {
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mgr.registerChecker<ArrayBoundChecker>();
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}
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bool ento::shouldRegisterArrayBoundChecker(const CheckerManager &mgr) {
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return true;
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}
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