8a5cfdf785
...because it provides no useful functionality compared to its base class `BugType`. A long time ago there were substantial differences between `BugType` and `BuiltinBug`, but they were eliminated by commit 1bd58233 in 2009 (!). Since then the only functionality provided by `BuiltinBug` was that it specified `categories::LogicError` as the bug category and it stored an extra data member `desc`. This commit sets `categories::LogicError` as the default value of the third argument (bug category) in the constructors of BugType and replaces use of the `desc` field with simpler logic. Note that `BugType` has a data member `Description` and a non-virtual method `BugType::getDescription()` which queries it; these are distinct from the member `desc` of `BuiltinBug` and the identically named method `BuiltinBug::getDescription()` which queries it. This confusing name collision was a major motivation for the elimination of `BuiltinBug`. As this commit touches many files, I avoided functional changes and left behind FIXME notes to mark minor issues that should be fixed later. Differential Revision: https://reviews.llvm.org/D158855
80 lines
2.6 KiB
C++
80 lines
2.6 KiB
C++
//=== PointerSubChecker.cpp - Pointer subtraction checker ------*- 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 files defines PointerSubChecker, a builtin checker that checks for
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// pointer subtractions on two pointers pointing to different memory chunks.
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// This check corresponds to CWE-469.
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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 "llvm/ADT/StringRef.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 PointerSubChecker
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: public Checker< check::PreStmt<BinaryOperator> > {
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mutable std::unique_ptr<BugType> BT;
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public:
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void checkPreStmt(const BinaryOperator *B, CheckerContext &C) const;
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};
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}
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void PointerSubChecker::checkPreStmt(const BinaryOperator *B,
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CheckerContext &C) const {
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// When doing pointer subtraction, if the two pointers do not point to the
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// same memory chunk, emit a warning.
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if (B->getOpcode() != BO_Sub)
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return;
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SVal LV = C.getSVal(B->getLHS());
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SVal RV = C.getSVal(B->getRHS());
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const MemRegion *LR = LV.getAsRegion();
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const MemRegion *RR = RV.getAsRegion();
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if (!(LR && RR))
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return;
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const MemRegion *BaseLR = LR->getBaseRegion();
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const MemRegion *BaseRR = RR->getBaseRegion();
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if (BaseLR == BaseRR)
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return;
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// Allow arithmetic on different symbolic regions.
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if (isa<SymbolicRegion>(BaseLR) || isa<SymbolicRegion>(BaseRR))
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return;
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if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
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if (!BT)
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BT.reset(new BugType(this, "Pointer subtraction"));
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constexpr llvm::StringLiteral Msg =
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"Subtraction of two pointers that do not point to the same memory "
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"chunk may cause incorrect result.";
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auto R = std::make_unique<PathSensitiveBugReport>(*BT, Msg, N);
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R->addRange(B->getSourceRange());
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C.emitReport(std::move(R));
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}
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}
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void ento::registerPointerSubChecker(CheckerManager &mgr) {
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mgr.registerChecker<PointerSubChecker>();
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}
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bool ento::shouldRegisterPointerSubChecker(const CheckerManager &mgr) {
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return true;
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}
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