1 //== ArrayBoundChecker.cpp ------------------------------*- C++ -*--==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines ArrayBoundChecker, which is a path-sensitive check
11 // which looks for an out-of-bound array element access.
13 //===----------------------------------------------------------------------===//
15 #include "ClangSACheckers.h"
16 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
17 #include "clang/StaticAnalyzer/Core/Checker.h"
18 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
19 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
20 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
22 using namespace clang;
26 class ArrayBoundChecker :
27 public Checker<check::Location> {
28 mutable OwningPtr<BuiltinBug> BT;
30 void checkLocation(SVal l, bool isLoad, const Stmt* S,
31 CheckerContext &C) const;
35 void ArrayBoundChecker::checkLocation(SVal l, bool isLoad, const Stmt* LoadS,
36 CheckerContext &C) const {
37 // Check for out of bound array element access.
38 const MemRegion *R = l.getAsRegion();
42 const ElementRegion *ER = dyn_cast<ElementRegion>(R);
46 // Get the index of the accessed element.
47 DefinedOrUnknownSVal Idx = ER->getIndex().castAs<DefinedOrUnknownSVal>();
49 // Zero index is always in bound, this also passes ElementRegions created for
51 if (Idx.isZeroConstant())
54 ProgramStateRef state = C.getState();
56 // Get the size of the array.
57 DefinedOrUnknownSVal NumElements
58 = C.getStoreManager().getSizeInElements(state, ER->getSuperRegion(),
61 ProgramStateRef StInBound = state->assumeInBound(Idx, NumElements, true);
62 ProgramStateRef StOutBound = state->assumeInBound(Idx, NumElements, false);
63 if (StOutBound && !StInBound) {
64 ExplodedNode *N = C.generateSink(StOutBound);
69 BT.reset(new BuiltinBug("Out-of-bound array access",
70 "Access out-of-bound array element (buffer overflow)"));
72 // FIXME: It would be nice to eventually make this diagnostic more clear,
73 // e.g., by referencing the original declaration or by saying *why* this
74 // reference is outside the range.
76 // Generate a report for this bug.
78 new BugReport(*BT, BT->getDescription(), N);
80 report->addRange(LoadS->getSourceRange());
85 // Array bound check succeeded. From this point forward the array bound
86 // should always succeed.
87 C.addTransition(StInBound);
90 void ento::registerArrayBoundChecker(CheckerManager &mgr) {
91 mgr.registerChecker<ArrayBoundChecker>();