24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/Support/raw_ostream.h"
27 using namespace clang;
29 using namespace taint;
32 class ArrayBoundCheckerV2 :
33 public Checker<check::Location> {
34 mutable std::unique_ptr<BuiltinBug> BT;
36 enum OOB_Kind { OOB_Precedes, OOB_Excedes, OOB_Tainted };
39 std::unique_ptr<BugReporterVisitor> Visitor =
nullptr)
const;
42 void checkLocation(SVal l,
bool isLoad,
const Stmt*S,
43 CheckerContext &C)
const;
47 class RegionRawOffsetV2 {
49 const SubRegion *baseRegion;
53 : baseRegion(nullptr), byteOffset(UnknownVal()) {}
56 RegionRawOffsetV2(
const SubRegion* base, SVal offset)
57 : baseRegion(base), byteOffset(offset) {}
59 NonLoc getByteOffset()
const {
return byteOffset.castAs<NonLoc>(); }
60 const SubRegion *getRegion()
const {
return baseRegion; }
63 SValBuilder &svalBuilder,
67 void dumpToStream(raw_ostream &os)
const;
72 const MemRegion *region) {
73 const MemSpaceRegion *SR = region->getMemorySpace();
74 if (SR->getKind() == MemRegion::UnknownSpaceRegionKind)
77 return svalBuilder.makeZeroArrayIndex();
84 static std::pair<NonLoc, nonloc::ConcreteInt>
86 SValBuilder &svalBuilder) {
88 if (SymVal && SymVal->isExpression()) {
89 if (
const SymIntExpr *SIE = dyn_cast<SymIntExpr>(SymVal->getSymbol())) {
91 APSIntType(extent.getValue()).convert(SIE->getRHS());
92 switch (SIE->getOpcode()) {
96 if ((extent.getValue() % constant) != 0)
97 return std::pair<NonLoc, nonloc::ConcreteInt>(offset, extent);
100 nonloc::SymbolVal(SIE->getLHS()),
101 svalBuilder.makeIntVal(extent.getValue() / constant),
105 nonloc::SymbolVal(SIE->getLHS()),
106 svalBuilder.makeIntVal(extent.getValue() - constant), svalBuilder);
113 return std::pair<NonLoc, nonloc::ConcreteInt>(offset, extent);
116 void ArrayBoundCheckerV2::checkLocation(SVal location,
bool isLoad,
118 CheckerContext &checkerContext)
const {
131 SValBuilder &svalBuilder = checkerContext.getSValBuilder();
132 const RegionRawOffsetV2 &rawOffset =
133 RegionRawOffsetV2::computeOffset(
state, svalBuilder, location);
135 if (!rawOffset.getRegion())
138 NonLoc rawOffsetVal = rawOffset.getByteOffset();
147 if (NV->getAs<nonloc::ConcreteInt>()) {
148 std::pair<NonLoc, nonloc::ConcreteInt> simplifiedOffsets =
150 NV->castAs<nonloc::ConcreteInt>(),
152 rawOffsetVal = simplifiedOffsets.first;
153 *NV = simplifiedOffsets.second;
156 SVal lowerBound = svalBuilder.evalBinOpNN(
state, BO_LT, rawOffsetVal, *NV,
157 svalBuilder.getConditionType());
160 if (!lowerBoundToCheck)
164 std::tie(state_precedesLowerBound, state_withinLowerBound) =
165 state->assume(*lowerBoundToCheck);
168 if (state_precedesLowerBound && !state_withinLowerBound) {
169 reportOOB(checkerContext, state_precedesLowerBound, OOB_Precedes);
174 assert(state_withinLowerBound);
175 state = state_withinLowerBound;
181 const MemRegion *MR = rawOffset.getRegion();
183 if (!
Size.getAs<NonLoc>())
186 if (
Size.getAs<nonloc::ConcreteInt>()) {
187 std::pair<NonLoc, nonloc::ConcreteInt> simplifiedOffsets =
189 Size.castAs<nonloc::ConcreteInt>(), svalBuilder);
190 rawOffsetVal = simplifiedOffsets.first;
191 Size = simplifiedOffsets.second;
194 SVal upperbound = svalBuilder.evalBinOpNN(
state, BO_GE, rawOffsetVal,
195 Size.castAs<NonLoc>(),
196 svalBuilder.getConditionType());
199 if (!upperboundToCheck)
203 std::tie(state_exceedsUpperBound, state_withinUpperBound) =
204 state->assume(*upperboundToCheck);
207 if (state_exceedsUpperBound && state_withinUpperBound) {
208 SVal ByteOffset = rawOffset.getByteOffset();
210 reportOOB(checkerContext, state_exceedsUpperBound, OOB_Tainted,
211 std::make_unique<TaintBugVisitor>(ByteOffset));
214 }
else if (state_exceedsUpperBound) {
217 assert(!state_withinUpperBound);
218 reportOOB(checkerContext, state_exceedsUpperBound, OOB_Excedes);
222 assert(state_withinUpperBound);
223 state = state_withinUpperBound;
227 checkerContext.addTransition(
state);
230 void ArrayBoundCheckerV2::reportOOB(
232 std::unique_ptr<BugReporterVisitor> Visitor)
const {
234 ExplodedNode *errorNode = checkerContext.generateErrorNode(errorState);
239 BT.reset(
new BuiltinBug(
this,
"Out-of-bound access"));
245 llvm::raw_svector_ostream os(buf);
246 os <<
"Out of bound memory access ";
249 os <<
"(accessed memory precedes memory block)";
252 os <<
"(access exceeds upper limit of memory block)";
255 os <<
"(index is tainted)";
259 auto BR = std::make_unique<PathSensitiveBugReport>(*BT, os.str(), errorNode);
260 BR->addVisitor(std::move(Visitor));
261 checkerContext.emitReport(std::move(BR));
266 dumpToStream(llvm::errs());
269 void RegionRawOffsetV2::dumpToStream(raw_ostream &os)
const {
270 os <<
"raw_offset_v2{" << getRegion() <<
',' << getByteOffset() <<
'}';
277 static inline SVal
getValue(SVal val, SValBuilder &svalBuilder) {
278 return val.getAs<UndefinedVal>() ? svalBuilder.makeArrayIndex(0) : val;
286 return sb.evalBinOpNN(
state, BO_Mul, baseVal,
288 sb.getArrayIndexType());
294 SValBuilder &svalBuilder) {
297 if (
x.isUnknownOrUndef() || y.isUnknownOrUndef())
300 return svalBuilder.evalBinOpNN(
state, BO_Add,
x.castAs<NonLoc>(),
302 svalBuilder.getArrayIndexType());
308 SValBuilder &svalBuilder,
311 const MemRegion *region = location.getAsRegion();
312 SVal offset = UndefinedVal();
315 switch (region->getKind()) {
317 if (
const SubRegion *subReg = dyn_cast<SubRegion>(region)) {
318 offset =
getValue(offset, svalBuilder);
319 if (!offset.isUnknownOrUndef())
320 return RegionRawOffsetV2(subReg, offset);
322 return RegionRawOffsetV2();
324 case MemRegion::ElementRegionKind: {
325 const ElementRegion *elemReg = cast<ElementRegion>(region);
326 SVal index = elemReg->getIndex();
327 if (!index.getAs<NonLoc>())
328 return RegionRawOffsetV2();
329 QualType elemType = elemReg->getElementType();
331 ASTContext &astContext = svalBuilder.getContext();
333 return RegionRawOffsetV2();
339 index.castAs<NonLoc>(),
344 if (offset.isUnknownOrUndef())
345 return RegionRawOffsetV2();
347 region = elemReg->getSuperRegion();
352 return RegionRawOffsetV2();
355 void ento::registerArrayBoundCheckerV2(CheckerManager &mgr) {
356 mgr.registerChecker<ArrayBoundCheckerV2>();
359 bool ento::shouldRegisterArrayBoundCheckerV2(
const CheckerManager &mgr) {