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author | dim <dim@FreeBSD.org> | 2013-04-08 18:45:10 +0000 |
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committer | dim <dim@FreeBSD.org> | 2013-04-08 18:45:10 +0000 |
commit | c72c57c9e9b69944e3e009cd5e209634839581d3 (patch) | |
tree | 4fc2f184c499d106f29a386c452b49e5197bf63d /lib/StaticAnalyzer/Checkers/MallocChecker.cpp | |
parent | 5b20025c30d23d521e12c1f33ec8fa6b821952cd (diff) | |
download | FreeBSD-src-c72c57c9e9b69944e3e009cd5e209634839581d3.zip FreeBSD-src-c72c57c9e9b69944e3e009cd5e209634839581d3.tar.gz |
Vendor import of clang trunk r178860:
http://llvm.org/svn/llvm-project/cfe/trunk@178860
Diffstat (limited to 'lib/StaticAnalyzer/Checkers/MallocChecker.cpp')
-rw-r--r-- | lib/StaticAnalyzer/Checkers/MallocChecker.cpp | 1096 |
1 files changed, 769 insertions, 327 deletions
diff --git a/lib/StaticAnalyzer/Checkers/MallocChecker.cpp b/lib/StaticAnalyzer/Checkers/MallocChecker.cpp index caf70ca..4b0e766 100644 --- a/lib/StaticAnalyzer/Checkers/MallocChecker.cpp +++ b/lib/StaticAnalyzer/Checkers/MallocChecker.cpp @@ -14,18 +14,19 @@ #include "ClangSACheckers.h" #include "InterCheckerAPI.h" +#include "clang/AST/Attr.h" +#include "clang/Basic/SourceManager.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/CheckerContext.h" -#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h" -#include "clang/Basic/SourceManager.h" #include "llvm/ADT/ImmutableMap.h" -#include "llvm/ADT/SmallString.h" #include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringExtras.h" #include <climits> @@ -34,6 +35,14 @@ using namespace ento; namespace { +// Used to check correspondence between allocators and deallocators. +enum AllocationFamily { + AF_None, + AF_Malloc, + AF_CXXNew, + AF_CXXNewArray +}; + class RefState { enum Kind { // Reference to allocated memory. Allocated, @@ -41,33 +50,55 @@ class RefState { Released, // The responsibility for freeing resources has transfered from // this reference. A relinquished symbol should not be freed. - Relinquished } K; + Relinquished }; + const Stmt *S; + unsigned K : 2; // Kind enum, but stored as a bitfield. + unsigned Family : 30; // Rest of 32-bit word, currently just an allocation + // family. + RefState(Kind k, const Stmt *s, unsigned family) + : S(s), K(k), Family(family) {} public: - RefState(Kind k, const Stmt *s) : K(k), S(s) {} - bool isAllocated() const { return K == Allocated; } bool isReleased() const { return K == Released; } bool isRelinquished() const { return K == Relinquished; } - + AllocationFamily getAllocationFamily() const { + return (AllocationFamily)Family; + } const Stmt *getStmt() const { return S; } bool operator==(const RefState &X) const { - return K == X.K && S == X.S; + return K == X.K && S == X.S && Family == X.Family; } - static RefState getAllocated(const Stmt *s) { - return RefState(Allocated, s); + static RefState getAllocated(unsigned family, const Stmt *s) { + return RefState(Allocated, s, family); + } + static RefState getReleased(unsigned family, const Stmt *s) { + return RefState(Released, s, family); } - static RefState getReleased(const Stmt *s) { return RefState(Released, s); } - static RefState getRelinquished(const Stmt *s) { - return RefState(Relinquished, s); + static RefState getRelinquished(unsigned family, const Stmt *s) { + return RefState(Relinquished, s, family); } void Profile(llvm::FoldingSetNodeID &ID) const { ID.AddInteger(K); ID.AddPointer(S); + ID.AddInteger(Family); + } + + void dump(raw_ostream &OS) const { + static const char *Table[] = { + "Allocated", + "Released", + "Relinquished" + }; + OS << Table[(unsigned) K]; + } + + LLVM_ATTRIBUTE_USED void dump() const { + dump(llvm::errs()); } }; @@ -99,24 +130,27 @@ struct ReallocPair { } }; -typedef std::pair<const Stmt*, const MemRegion*> LeakInfo; +typedef std::pair<const ExplodedNode*, const MemRegion*> LeakInfo; class MallocChecker : public Checker<check::DeadSymbols, - check::EndPath, + check::PointerEscape, + check::ConstPointerEscape, check::PreStmt<ReturnStmt>, check::PreStmt<CallExpr>, check::PostStmt<CallExpr>, + check::PostStmt<CXXNewExpr>, + check::PreStmt<CXXDeleteExpr>, check::PostStmt<BlockExpr>, check::PostObjCMessage, check::Location, - check::Bind, - eval::Assume, - check::RegionChanges> + eval::Assume> { mutable OwningPtr<BugType> BT_DoubleFree; mutable OwningPtr<BugType> BT_Leak; mutable OwningPtr<BugType> BT_UseFree; mutable OwningPtr<BugType> BT_BadFree; + mutable OwningPtr<BugType> BT_MismatchedDealloc; + mutable OwningPtr<BugType> BT_OffsetFree; mutable IdentifierInfo *II_malloc, *II_free, *II_realloc, *II_calloc, *II_valloc, *II_reallocf, *II_strndup, *II_strdup; @@ -129,32 +163,33 @@ public: struct ChecksFilter { DefaultBool CMallocPessimistic; DefaultBool CMallocOptimistic; + DefaultBool CNewDeleteChecker; + DefaultBool CMismatchedDeallocatorChecker; }; ChecksFilter Filter; void checkPreStmt(const CallExpr *S, CheckerContext &C) const; void checkPostStmt(const CallExpr *CE, CheckerContext &C) const; + void checkPostStmt(const CXXNewExpr *NE, CheckerContext &C) const; + void checkPreStmt(const CXXDeleteExpr *DE, CheckerContext &C) const; void checkPostObjCMessage(const ObjCMethodCall &Call, CheckerContext &C) const; void checkPostStmt(const BlockExpr *BE, CheckerContext &C) const; void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; - void checkEndPath(CheckerContext &C) const; void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; ProgramStateRef evalAssume(ProgramStateRef state, SVal Cond, bool Assumption) const; void checkLocation(SVal l, bool isLoad, const Stmt *S, CheckerContext &C) const; - void checkBind(SVal location, SVal val, const Stmt*S, - CheckerContext &C) const; - ProgramStateRef - checkRegionChanges(ProgramStateRef state, - const StoreManager::InvalidatedSymbols *invalidated, - ArrayRef<const MemRegion *> ExplicitRegions, - ArrayRef<const MemRegion *> Regions, - const CallEvent *Call) const; - bool wantsRegionChangeUpdate(ProgramStateRef state) const { - return true; - } + + ProgramStateRef checkPointerEscape(ProgramStateRef State, + const InvalidatedSymbols &Escaped, + const CallEvent *Call, + PointerEscapeKind Kind) const; + ProgramStateRef checkConstPointerEscape(ProgramStateRef State, + const InvalidatedSymbols &Escaped, + const CallEvent *Call, + PointerEscapeKind Kind) const; void printState(raw_ostream &Out, ProgramStateRef State, const char *NL, const char *Sep) const; @@ -162,31 +197,52 @@ public: private: void initIdentifierInfo(ASTContext &C) const; + /// \brief Determine family of a deallocation expression. + AllocationFamily getAllocationFamily(CheckerContext &C, const Stmt *S) const; + + /// \brief Print names of allocators and deallocators. + /// + /// \returns true on success. + bool printAllocDeallocName(raw_ostream &os, CheckerContext &C, + const Expr *E) const; + + /// \brief Print expected name of an allocator based on the deallocator's + /// family derived from the DeallocExpr. + void printExpectedAllocName(raw_ostream &os, CheckerContext &C, + const Expr *DeallocExpr) const; + /// \brief Print expected name of a deallocator based on the allocator's + /// family. + void printExpectedDeallocName(raw_ostream &os, AllocationFamily Family) const; + + ///@{ /// Check if this is one of the functions which can allocate/reallocate memory /// pointed to by one of its arguments. bool isMemFunction(const FunctionDecl *FD, ASTContext &C) const; bool isFreeFunction(const FunctionDecl *FD, ASTContext &C) const; bool isAllocationFunction(const FunctionDecl *FD, ASTContext &C) const; - + bool isStandardNewDelete(const FunctionDecl *FD, ASTContext &C) const; + ///@} static ProgramStateRef MallocMemReturnsAttr(CheckerContext &C, const CallExpr *CE, const OwnershipAttr* Att); static ProgramStateRef MallocMemAux(CheckerContext &C, const CallExpr *CE, const Expr *SizeEx, SVal Init, - ProgramStateRef state) { + ProgramStateRef State, + AllocationFamily Family = AF_Malloc) { return MallocMemAux(C, CE, - state->getSVal(SizeEx, C.getLocationContext()), - Init, state); + State->getSVal(SizeEx, C.getLocationContext()), + Init, State, Family); } static ProgramStateRef MallocMemAux(CheckerContext &C, const CallExpr *CE, SVal SizeEx, SVal Init, - ProgramStateRef state); + ProgramStateRef State, + AllocationFamily Family = AF_Malloc); /// Update the RefState to reflect the new memory allocation. - static ProgramStateRef MallocUpdateRefState(CheckerContext &C, - const CallExpr *CE, - ProgramStateRef state); + static ProgramStateRef + MallocUpdateRefState(CheckerContext &C, const Expr *E, ProgramStateRef State, + AllocationFamily Family = AF_Malloc); ProgramStateRef FreeMemAttr(CheckerContext &C, const CallExpr *CE, const OwnershipAttr* Att) const; @@ -209,17 +265,43 @@ private: ///\brief Check if the memory associated with this symbol was released. bool isReleased(SymbolRef Sym, CheckerContext &C) const; - bool checkUseAfterFree(SymbolRef Sym, CheckerContext &C, - const Stmt *S = 0) const; - - /// Check if the function is not known to us. So, for example, we could - /// conservatively assume it can free/reallocate it's pointer arguments. - bool doesNotFreeMemory(const CallEvent *Call, - ProgramStateRef State) const; + bool checkUseAfterFree(SymbolRef Sym, CheckerContext &C, const Stmt *S) const; + + /// Check if the function is known not to free memory, or if it is + /// "interesting" and should be modeled explicitly. + /// + /// We assume that pointers do not escape through calls to system functions + /// not handled by this checker. + bool doesNotFreeMemOrInteresting(const CallEvent *Call, + ProgramStateRef State) const; + + // Implementation of the checkPointerEscape callabcks. + ProgramStateRef checkPointerEscapeAux(ProgramStateRef State, + const InvalidatedSymbols &Escaped, + const CallEvent *Call, + PointerEscapeKind Kind, + bool(*CheckRefState)(const RefState*)) const; + + // Used to suppress warnings if they are not related to the tracked family + // (derived from AllocDeallocStmt). + bool isTrackedFamily(AllocationFamily Family) const; + bool isTrackedFamily(CheckerContext &C, const Stmt *AllocDeallocStmt) const; + bool isTrackedFamily(CheckerContext &C, SymbolRef Sym) const; static bool SummarizeValue(raw_ostream &os, SVal V); static bool SummarizeRegion(raw_ostream &os, const MemRegion *MR); - void ReportBadFree(CheckerContext &C, SVal ArgVal, SourceRange range) const; + void ReportBadFree(CheckerContext &C, SVal ArgVal, SourceRange Range, + const Expr *DeallocExpr) const; + void ReportMismatchedDealloc(CheckerContext &C, SourceRange Range, + const Expr *DeallocExpr, + const RefState *RS) const; + void ReportOffsetFree(CheckerContext &C, SVal ArgVal, SourceRange Range, + const Expr *DeallocExpr, + const Expr *AllocExpr = 0) const; + void ReportUseAfterFree(CheckerContext &C, SourceRange Range, + SymbolRef Sym) const; + void ReportDoubleFree(CheckerContext &C, SourceRange Range, bool Released, + SymbolRef Sym, SymbolRef PrevSym) const; /// Find the location of the allocation for Sym on the path leading to the /// exploded node N. @@ -264,14 +346,14 @@ private: inline bool isAllocated(const RefState *S, const RefState *SPrev, const Stmt *Stmt) { // Did not track -> allocated. Other state (released) -> allocated. - return (Stmt && isa<CallExpr>(Stmt) && + return (Stmt && (isa<CallExpr>(Stmt) || isa<CXXNewExpr>(Stmt)) && (S && S->isAllocated()) && (!SPrev || !SPrev->isAllocated())); } inline bool isReleased(const RefState *S, const RefState *SPrev, const Stmt *Stmt) { // Did not track -> released. Other state (allocated) -> released. - return (Stmt && isa<CallExpr>(Stmt) && + return (Stmt && (isa<CallExpr>(Stmt) || isa<CXXDeleteExpr>(Stmt)) && (S && S->isReleased()) && (!SPrev || !SPrev->isReleased())); } @@ -381,6 +463,9 @@ bool MallocChecker::isMemFunction(const FunctionDecl *FD, ASTContext &C) const { if (isAllocationFunction(FD, C)) return true; + if (isStandardNewDelete(FD, C)) + return true; + return false; } @@ -432,6 +517,39 @@ bool MallocChecker::isFreeFunction(const FunctionDecl *FD, ASTContext &C) const return false; } +// Tells if the callee is one of the following: +// 1) A global non-placement new/delete operator function. +// 2) A global placement operator function with the single placement argument +// of type std::nothrow_t. +bool MallocChecker::isStandardNewDelete(const FunctionDecl *FD, + ASTContext &C) const { + if (!FD) + return false; + + OverloadedOperatorKind Kind = FD->getOverloadedOperator(); + if (Kind != OO_New && Kind != OO_Array_New && + Kind != OO_Delete && Kind != OO_Array_Delete) + return false; + + // Skip all operator new/delete methods. + if (isa<CXXMethodDecl>(FD)) + return false; + + // Return true if tested operator is a standard placement nothrow operator. + if (FD->getNumParams() == 2) { + QualType T = FD->getParamDecl(1)->getType(); + if (const IdentifierInfo *II = T.getBaseTypeIdentifier()) + return II->getName().equals("nothrow_t"); + } + + // Skip placement operators. + if (FD->getNumParams() != 1 || FD->isVariadic()) + return false; + + // One of the standard new/new[]/delete/delete[] non-placement operators. + return true; +} + void MallocChecker::checkPostStmt(const CallExpr *CE, CheckerContext &C) const { if (C.wasInlined) return; @@ -464,9 +582,26 @@ void MallocChecker::checkPostStmt(const CallExpr *CE, CheckerContext &C) const { } else if (FunI == II_strndup) { State = MallocUpdateRefState(C, CE, State); } + else if (isStandardNewDelete(FD, C.getASTContext())) { + // Process direct calls to operator new/new[]/delete/delete[] functions + // as distinct from new/new[]/delete/delete[] expressions that are + // processed by the checkPostStmt callbacks for CXXNewExpr and + // CXXDeleteExpr. + OverloadedOperatorKind K = FD->getOverloadedOperator(); + if (K == OO_New) + State = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State, + AF_CXXNew); + else if (K == OO_Array_New) + State = MallocMemAux(C, CE, CE->getArg(0), UndefinedVal(), State, + AF_CXXNewArray); + else if (K == OO_Delete || K == OO_Array_Delete) + State = FreeMemAux(C, CE, State, 0, false, ReleasedAllocatedMemory); + else + llvm_unreachable("not a new/delete operator"); + } } - if (Filter.CMallocOptimistic) { + if (Filter.CMallocOptimistic || Filter.CMismatchedDeallocatorChecker) { // Check all the attributes, if there are any. // There can be multiple of these attributes. if (FD->hasAttrs()) @@ -488,37 +623,91 @@ void MallocChecker::checkPostStmt(const CallExpr *CE, CheckerContext &C) const { C.addTransition(State); } -static bool isFreeWhenDoneSetToZero(const ObjCMethodCall &Call) { +void MallocChecker::checkPostStmt(const CXXNewExpr *NE, + CheckerContext &C) const { + + if (NE->getNumPlacementArgs()) + for (CXXNewExpr::const_arg_iterator I = NE->placement_arg_begin(), + E = NE->placement_arg_end(); I != E; ++I) + if (SymbolRef Sym = C.getSVal(*I).getAsSymbol()) + checkUseAfterFree(Sym, C, *I); + + if (!isStandardNewDelete(NE->getOperatorNew(), C.getASTContext())) + return; + + ProgramStateRef State = C.getState(); + // The return value from operator new is bound to a specified initialization + // value (if any) and we don't want to loose this value. So we call + // MallocUpdateRefState() instead of MallocMemAux() which breakes the + // existing binding. + State = MallocUpdateRefState(C, NE, State, NE->isArray() ? AF_CXXNewArray + : AF_CXXNew); + C.addTransition(State); +} + +void MallocChecker::checkPreStmt(const CXXDeleteExpr *DE, + CheckerContext &C) const { + + if (!Filter.CNewDeleteChecker) + if (SymbolRef Sym = C.getSVal(DE->getArgument()).getAsSymbol()) + checkUseAfterFree(Sym, C, DE->getArgument()); + + if (!isStandardNewDelete(DE->getOperatorDelete(), C.getASTContext())) + return; + + ProgramStateRef State = C.getState(); + bool ReleasedAllocated; + State = FreeMemAux(C, DE->getArgument(), DE, State, + /*Hold*/false, ReleasedAllocated); + + C.addTransition(State); +} + +static bool isKnownDeallocObjCMethodName(const ObjCMethodCall &Call) { + // If the first selector piece is one of the names below, assume that the + // object takes ownership of the memory, promising to eventually deallocate it + // with free(). + // Ex: [NSData dataWithBytesNoCopy:bytes length:10]; + // (...unless a 'freeWhenDone' parameter is false, but that's checked later.) + StringRef FirstSlot = Call.getSelector().getNameForSlot(0); + if (FirstSlot == "dataWithBytesNoCopy" || + FirstSlot == "initWithBytesNoCopy" || + FirstSlot == "initWithCharactersNoCopy") + return true; + + return false; +} + +static Optional<bool> getFreeWhenDoneArg(const ObjCMethodCall &Call) { Selector S = Call.getSelector(); + + // FIXME: We should not rely on fully-constrained symbols being folded. for (unsigned i = 1; i < S.getNumArgs(); ++i) if (S.getNameForSlot(i).equals("freeWhenDone")) - if (Call.getArgSVal(i).isConstant(0)) - return true; + return !Call.getArgSVal(i).isZeroConstant(); - return false; + return None; } void MallocChecker::checkPostObjCMessage(const ObjCMethodCall &Call, CheckerContext &C) const { - // If the first selector is dataWithBytesNoCopy, assume that the memory will - // be released with 'free' by the new object. - // Ex: [NSData dataWithBytesNoCopy:bytes length:10]; - // Unless 'freeWhenDone' param set to 0. - // TODO: Check that the memory was allocated with malloc. - bool ReleasedAllocatedMemory = false; - Selector S = Call.getSelector(); - if ((S.getNameForSlot(0) == "dataWithBytesNoCopy" || - S.getNameForSlot(0) == "initWithBytesNoCopy" || - S.getNameForSlot(0) == "initWithCharactersNoCopy") && - !isFreeWhenDoneSetToZero(Call)){ - unsigned int argIdx = 0; - ProgramStateRef State = FreeMemAux(C, Call.getArgExpr(argIdx), - Call.getOriginExpr(), C.getState(), true, - ReleasedAllocatedMemory, - /* RetNullOnFailure*/ true); - - C.addTransition(State); - } + if (C.wasInlined) + return; + + if (!isKnownDeallocObjCMethodName(Call)) + return; + + if (Optional<bool> FreeWhenDone = getFreeWhenDoneArg(Call)) + if (!*FreeWhenDone) + return; + + bool ReleasedAllocatedMemory; + ProgramStateRef State = FreeMemAux(C, Call.getArgExpr(0), + Call.getOriginExpr(), C.getState(), + /*Hold=*/true, ReleasedAllocatedMemory, + /*RetNullOnFailure=*/true); + + C.addTransition(State); } ProgramStateRef MallocChecker::MallocMemReturnsAttr(CheckerContext &C, @@ -537,7 +726,8 @@ ProgramStateRef MallocChecker::MallocMemReturnsAttr(CheckerContext &C, ProgramStateRef MallocChecker::MallocMemAux(CheckerContext &C, const CallExpr *CE, SVal Size, SVal Init, - ProgramStateRef state) { + ProgramStateRef State, + AllocationFamily Family) { // Bind the return value to the symbolic value from the heap region. // TODO: We could rewrite post visit to eval call; 'malloc' does not have @@ -545,52 +735,52 @@ ProgramStateRef MallocChecker::MallocMemAux(CheckerContext &C, unsigned Count = C.blockCount(); SValBuilder &svalBuilder = C.getSValBuilder(); const LocationContext *LCtx = C.getPredecessor()->getLocationContext(); - DefinedSVal RetVal = - cast<DefinedSVal>(svalBuilder.getConjuredHeapSymbolVal(CE, LCtx, Count)); - state = state->BindExpr(CE, C.getLocationContext(), RetVal); + DefinedSVal RetVal = svalBuilder.getConjuredHeapSymbolVal(CE, LCtx, Count) + .castAs<DefinedSVal>(); + State = State->BindExpr(CE, C.getLocationContext(), RetVal); // We expect the malloc functions to return a pointer. - if (!isa<Loc>(RetVal)) + if (!RetVal.getAs<Loc>()) return 0; // Fill the region with the initialization value. - state = state->bindDefault(RetVal, Init); + State = State->bindDefault(RetVal, Init); // Set the region's extent equal to the Size parameter. const SymbolicRegion *R = dyn_cast_or_null<SymbolicRegion>(RetVal.getAsRegion()); if (!R) return 0; - if (isa<DefinedOrUnknownSVal>(Size)) { + if (Optional<DefinedOrUnknownSVal> DefinedSize = + Size.getAs<DefinedOrUnknownSVal>()) { SValBuilder &svalBuilder = C.getSValBuilder(); DefinedOrUnknownSVal Extent = R->getExtent(svalBuilder); - DefinedOrUnknownSVal DefinedSize = cast<DefinedOrUnknownSVal>(Size); DefinedOrUnknownSVal extentMatchesSize = - svalBuilder.evalEQ(state, Extent, DefinedSize); + svalBuilder.evalEQ(State, Extent, *DefinedSize); - state = state->assume(extentMatchesSize, true); - assert(state); + State = State->assume(extentMatchesSize, true); + assert(State); } - return MallocUpdateRefState(C, CE, state); + return MallocUpdateRefState(C, CE, State, Family); } ProgramStateRef MallocChecker::MallocUpdateRefState(CheckerContext &C, - const CallExpr *CE, - ProgramStateRef state) { + const Expr *E, + ProgramStateRef State, + AllocationFamily Family) { // Get the return value. - SVal retVal = state->getSVal(CE, C.getLocationContext()); + SVal retVal = State->getSVal(E, C.getLocationContext()); // We expect the malloc functions to return a pointer. - if (!isa<Loc>(retVal)) + if (!retVal.getAs<Loc>()) return 0; SymbolRef Sym = retVal.getAsLocSymbol(); assert(Sym); // Set the symbol's state to Allocated. - return state->set<RegionState>(Sym, RefState::getAllocated(CE)); - + return State->set<RegionState>(Sym, RefState::getAllocated(Family, E)); } ProgramStateRef MallocChecker::FreeMemAttr(CheckerContext &C, @@ -629,8 +819,8 @@ ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C, /// Checks if the previous call to free on the given symbol failed - if free /// failed, returns true. Also, returns the corresponding return value symbol. -bool didPreviousFreeFail(ProgramStateRef State, - SymbolRef Sym, SymbolRef &RetStatusSymbol) { +static bool didPreviousFreeFail(ProgramStateRef State, + SymbolRef Sym, SymbolRef &RetStatusSymbol) { const SymbolRef *Ret = State->get<FreeReturnValue>(Sym); if (Ret) { assert(*Ret && "We should not store the null return symbol"); @@ -642,6 +832,107 @@ bool didPreviousFreeFail(ProgramStateRef State, return false; } +AllocationFamily MallocChecker::getAllocationFamily(CheckerContext &C, + const Stmt *S) const { + if (!S) + return AF_None; + + if (const CallExpr *CE = dyn_cast<CallExpr>(S)) { + const FunctionDecl *FD = C.getCalleeDecl(CE); + + if (!FD) + FD = dyn_cast<FunctionDecl>(CE->getCalleeDecl()); + + ASTContext &Ctx = C.getASTContext(); + + if (isAllocationFunction(FD, Ctx) || isFreeFunction(FD, Ctx)) + return AF_Malloc; + + if (isStandardNewDelete(FD, Ctx)) { + OverloadedOperatorKind Kind = FD->getOverloadedOperator(); + if (Kind == OO_New || Kind == OO_Delete) + return AF_CXXNew; + else if (Kind == OO_Array_New || Kind == OO_Array_Delete) + return AF_CXXNewArray; + } + + return AF_None; + } + + if (const CXXNewExpr *NE = dyn_cast<CXXNewExpr>(S)) + return NE->isArray() ? AF_CXXNewArray : AF_CXXNew; + + if (const CXXDeleteExpr *DE = dyn_cast<CXXDeleteExpr>(S)) + return DE->isArrayForm() ? AF_CXXNewArray : AF_CXXNew; + + if (isa<ObjCMessageExpr>(S)) + return AF_Malloc; + + return AF_None; +} + +bool MallocChecker::printAllocDeallocName(raw_ostream &os, CheckerContext &C, + const Expr *E) const { + if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { + // FIXME: This doesn't handle indirect calls. + const FunctionDecl *FD = CE->getDirectCallee(); + if (!FD) + return false; + + os << *FD; + if (!FD->isOverloadedOperator()) + os << "()"; + return true; + } + + if (const ObjCMessageExpr *Msg = dyn_cast<ObjCMessageExpr>(E)) { + if (Msg->isInstanceMessage()) + os << "-"; + else + os << "+"; + os << Msg->getSelector().getAsString(); + return true; + } + + if (const CXXNewExpr *NE = dyn_cast<CXXNewExpr>(E)) { + os << "'" + << getOperatorSpelling(NE->getOperatorNew()->getOverloadedOperator()) + << "'"; + return true; + } + + if (const CXXDeleteExpr *DE = dyn_cast<CXXDeleteExpr>(E)) { + os << "'" + << getOperatorSpelling(DE->getOperatorDelete()->getOverloadedOperator()) + << "'"; + return true; + } + + return false; +} + +void MallocChecker::printExpectedAllocName(raw_ostream &os, CheckerContext &C, + const Expr *E) const { + AllocationFamily Family = getAllocationFamily(C, E); + + switch(Family) { + case AF_Malloc: os << "malloc()"; return; + case AF_CXXNew: os << "'new'"; return; + case AF_CXXNewArray: os << "'new[]'"; return; + case AF_None: llvm_unreachable("not a deallocation expression"); + } +} + +void MallocChecker::printExpectedDeallocName(raw_ostream &os, + AllocationFamily Family) const { + switch(Family) { + case AF_Malloc: os << "free()"; return; + case AF_CXXNew: os << "'delete'"; return; + case AF_CXXNewArray: os << "'delete[]'"; return; + case AF_None: llvm_unreachable("suspicious AF_None argument"); + } +} + ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C, const Expr *ArgExpr, const Expr *ParentExpr, @@ -651,12 +942,12 @@ ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C, bool ReturnsNullOnFailure) const { SVal ArgVal = State->getSVal(ArgExpr, C.getLocationContext()); - if (!isa<DefinedOrUnknownSVal>(ArgVal)) + if (!ArgVal.getAs<DefinedOrUnknownSVal>()) return 0; - DefinedOrUnknownSVal location = cast<DefinedOrUnknownSVal>(ArgVal); + DefinedOrUnknownSVal location = ArgVal.castAs<DefinedOrUnknownSVal>(); // Check for null dereferences. - if (!isa<Loc>(location)) + if (!location.getAs<Loc>()) return 0; // The explicit NULL case, no operation is performed. @@ -675,7 +966,7 @@ ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C, // Nonlocs can't be freed, of course. // Non-region locations (labels and fixed addresses) also shouldn't be freed. if (!R) { - ReportBadFree(C, ArgVal, ArgExpr->getSourceRange()); + ReportBadFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr); return 0; } @@ -683,13 +974,14 @@ ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C, // Blocks might show up as heap data, but should not be free()d if (isa<BlockDataRegion>(R)) { - ReportBadFree(C, ArgVal, ArgExpr->getSourceRange()); + ReportBadFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr); return 0; } const MemSpaceRegion *MS = R->getMemorySpace(); - // Parameters, locals, statics, and globals shouldn't be freed. + // Parameters, locals, statics, globals, and memory returned by alloca() + // shouldn't be freed. if (!(isa<UnknownSpaceRegion>(MS) || isa<HeapSpaceRegion>(MS))) { // FIXME: at the time this code was written, malloc() regions were // represented by conjured symbols, which are all in UnknownSpaceRegion. @@ -699,46 +991,59 @@ ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C, // function, so UnknownSpaceRegion is always a possibility. // False negatives are better than false positives. - ReportBadFree(C, ArgVal, ArgExpr->getSourceRange()); + ReportBadFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr); return 0; } - - const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R); + + const SymbolicRegion *SrBase = dyn_cast<SymbolicRegion>(R->getBaseRegion()); // Various cases could lead to non-symbol values here. // For now, ignore them. - if (!SR) + if (!SrBase) return 0; - SymbolRef Sym = SR->getSymbol(); - const RefState *RS = State->get<RegionState>(Sym); + SymbolRef SymBase = SrBase->getSymbol(); + const RefState *RsBase = State->get<RegionState>(SymBase); SymbolRef PreviousRetStatusSymbol = 0; - // Check double free. - if (RS && - (RS->isReleased() || RS->isRelinquished()) && - !didPreviousFreeFail(State, Sym, PreviousRetStatusSymbol)) { - - if (ExplodedNode *N = C.generateSink()) { - if (!BT_DoubleFree) - BT_DoubleFree.reset( - new BugType("Double free", "Memory Error")); - BugReport *R = new BugReport(*BT_DoubleFree, - (RS->isReleased() ? "Attempt to free released memory" : - "Attempt to free non-owned memory"), N); - R->addRange(ArgExpr->getSourceRange()); - R->markInteresting(Sym); - if (PreviousRetStatusSymbol) - R->markInteresting(PreviousRetStatusSymbol); - R->addVisitor(new MallocBugVisitor(Sym)); - C.emitReport(R); + if (RsBase) { + + bool DeallocMatchesAlloc = + RsBase->getAllocationFamily() == AF_None || + RsBase->getAllocationFamily() == getAllocationFamily(C, ParentExpr); + + // Check if an expected deallocation function matches the real one. + if (!DeallocMatchesAlloc && RsBase->isAllocated()) { + ReportMismatchedDealloc(C, ArgExpr->getSourceRange(), ParentExpr, RsBase); + return 0; + } + + // Check double free. + if (DeallocMatchesAlloc && + (RsBase->isReleased() || RsBase->isRelinquished()) && + !didPreviousFreeFail(State, SymBase, PreviousRetStatusSymbol)) { + ReportDoubleFree(C, ParentExpr->getSourceRange(), RsBase->isReleased(), + SymBase, PreviousRetStatusSymbol); + return 0; + } + + // Check if the memory location being freed is the actual location + // allocated, or an offset. + RegionOffset Offset = R->getAsOffset(); + if (RsBase->isAllocated() && + Offset.isValid() && + !Offset.hasSymbolicOffset() && + Offset.getOffset() != 0) { + const Expr *AllocExpr = cast<Expr>(RsBase->getStmt()); + ReportOffsetFree(C, ArgVal, ArgExpr->getSourceRange(), ParentExpr, + AllocExpr); + return 0; } - return 0; } - ReleasedAllocated = (RS != 0); + ReleasedAllocated = (RsBase != 0); // Clean out the info on previous call to free return info. - State = State->remove<FreeReturnValue>(Sym); + State = State->remove<FreeReturnValue>(SymBase); // Keep track of the return value. If it is NULL, we will know that free // failed. @@ -746,23 +1051,60 @@ ProgramStateRef MallocChecker::FreeMemAux(CheckerContext &C, SVal RetVal = C.getSVal(ParentExpr); SymbolRef RetStatusSymbol = RetVal.getAsSymbol(); if (RetStatusSymbol) { - C.getSymbolManager().addSymbolDependency(Sym, RetStatusSymbol); - State = State->set<FreeReturnValue>(Sym, RetStatusSymbol); + C.getSymbolManager().addSymbolDependency(SymBase, RetStatusSymbol); + State = State->set<FreeReturnValue>(SymBase, RetStatusSymbol); } } + AllocationFamily Family = RsBase ? RsBase->getAllocationFamily() : AF_None; // Normal free. if (Hold) - return State->set<RegionState>(Sym, RefState::getRelinquished(ParentExpr)); - return State->set<RegionState>(Sym, RefState::getReleased(ParentExpr)); + return State->set<RegionState>(SymBase, + RefState::getRelinquished(Family, + ParentExpr)); + + return State->set<RegionState>(SymBase, + RefState::getReleased(Family, ParentExpr)); +} + +bool MallocChecker::isTrackedFamily(AllocationFamily Family) const { + switch (Family) { + case AF_Malloc: { + if (!Filter.CMallocOptimistic && !Filter.CMallocPessimistic) + return false; + return true; + } + case AF_CXXNew: + case AF_CXXNewArray: { + if (!Filter.CNewDeleteChecker) + return false; + return true; + } + case AF_None: { + return true; + } + } + llvm_unreachable("unhandled family"); +} + +bool MallocChecker::isTrackedFamily(CheckerContext &C, + const Stmt *AllocDeallocStmt) const { + return isTrackedFamily(getAllocationFamily(C, AllocDeallocStmt)); +} + +bool MallocChecker::isTrackedFamily(CheckerContext &C, SymbolRef Sym) const { + const RefState *RS = C.getState()->get<RegionState>(Sym); + + return RS ? isTrackedFamily(RS->getAllocationFamily()) + : isTrackedFamily(AF_None); } bool MallocChecker::SummarizeValue(raw_ostream &os, SVal V) { - if (nonloc::ConcreteInt *IntVal = dyn_cast<nonloc::ConcreteInt>(&V)) + if (Optional<nonloc::ConcreteInt> IntVal = V.getAs<nonloc::ConcreteInt>()) os << "an integer (" << IntVal->getValue() << ")"; - else if (loc::ConcreteInt *ConstAddr = dyn_cast<loc::ConcreteInt>(&V)) + else if (Optional<loc::ConcreteInt> ConstAddr = V.getAs<loc::ConcreteInt>()) os << "a constant address (" << ConstAddr->getValue() << ")"; - else if (loc::GotoLabel *Label = dyn_cast<loc::GotoLabel>(&V)) + else if (Optional<loc::GotoLabel> Label = V.getAs<loc::GotoLabel>()) os << "the address of the label '" << Label->getLabel()->getName() << "'"; else return false; @@ -844,41 +1186,192 @@ bool MallocChecker::SummarizeRegion(raw_ostream &os, } } -void MallocChecker::ReportBadFree(CheckerContext &C, SVal ArgVal, - SourceRange range) const { +void MallocChecker::ReportBadFree(CheckerContext &C, SVal ArgVal, + SourceRange Range, + const Expr *DeallocExpr) const { + + if (!Filter.CMallocOptimistic && !Filter.CMallocPessimistic && + !Filter.CNewDeleteChecker) + return; + + if (!isTrackedFamily(C, DeallocExpr)) + return; + if (ExplodedNode *N = C.generateSink()) { if (!BT_BadFree) BT_BadFree.reset(new BugType("Bad free", "Memory Error")); SmallString<100> buf; llvm::raw_svector_ostream os(buf); - + const MemRegion *MR = ArgVal.getAsRegion(); - if (MR) { - while (const ElementRegion *ER = dyn_cast<ElementRegion>(MR)) - MR = ER->getSuperRegion(); - - // Special case for alloca() - if (isa<AllocaRegion>(MR)) - os << "Argument to free() was allocated by alloca(), not malloc()"; - else { - os << "Argument to free() is "; - if (SummarizeRegion(os, MR)) - os << ", which is not memory allocated by malloc()"; - else - os << "not memory allocated by malloc()"; - } - } else { - os << "Argument to free() is "; - if (SummarizeValue(os, ArgVal)) - os << ", which is not memory allocated by malloc()"; + while (const ElementRegion *ER = dyn_cast_or_null<ElementRegion>(MR)) + MR = ER->getSuperRegion(); + + if (MR && isa<AllocaRegion>(MR)) + os << "Memory allocated by alloca() should not be deallocated"; + else { + os << "Argument to "; + if (!printAllocDeallocName(os, C, DeallocExpr)) + os << "deallocator"; + + os << " is "; + bool Summarized = MR ? SummarizeRegion(os, MR) + : SummarizeValue(os, ArgVal); + if (Summarized) + os << ", which is not memory allocated by "; else - os << "not memory allocated by malloc()"; + os << "not memory allocated by "; + + printExpectedAllocName(os, C, DeallocExpr); } - + BugReport *R = new BugReport(*BT_BadFree, os.str(), N); R->markInteresting(MR); - R->addRange(range); + R->addRange(Range); + C.emitReport(R); + } +} + +void MallocChecker::ReportMismatchedDealloc(CheckerContext &C, + SourceRange Range, + const Expr *DeallocExpr, + const RefState *RS) const { + + if (!Filter.CMismatchedDeallocatorChecker) + return; + + if (ExplodedNode *N = C.generateSink()) { + if (!BT_MismatchedDealloc) + BT_MismatchedDealloc.reset(new BugType("Bad deallocator", + "Memory Error")); + + SmallString<100> buf; + llvm::raw_svector_ostream os(buf); + + const Expr *AllocExpr = cast<Expr>(RS->getStmt()); + SmallString<20> AllocBuf; + llvm::raw_svector_ostream AllocOs(AllocBuf); + SmallString<20> DeallocBuf; + llvm::raw_svector_ostream DeallocOs(DeallocBuf); + + os << "Memory"; + if (printAllocDeallocName(AllocOs, C, AllocExpr)) + os << " allocated by " << AllocOs.str(); + + os << " should be deallocated by "; + printExpectedDeallocName(os, RS->getAllocationFamily()); + + if (printAllocDeallocName(DeallocOs, C, DeallocExpr)) + os << ", not " << DeallocOs.str(); + + BugReport *R = new BugReport(*BT_MismatchedDealloc, os.str(), N); + R->addRange(Range); + C.emitReport(R); + } +} + +void MallocChecker::ReportOffsetFree(CheckerContext &C, SVal ArgVal, + SourceRange Range, const Expr *DeallocExpr, + const Expr *AllocExpr) const { + + if (!Filter.CMallocOptimistic && !Filter.CMallocPessimistic && + !Filter.CNewDeleteChecker) + return; + + if (!isTrackedFamily(C, AllocExpr)) + return; + + ExplodedNode *N = C.generateSink(); + if (N == NULL) + return; + + if (!BT_OffsetFree) + BT_OffsetFree.reset(new BugType("Offset free", "Memory Error")); + + SmallString<100> buf; + llvm::raw_svector_ostream os(buf); + SmallString<20> AllocNameBuf; + llvm::raw_svector_ostream AllocNameOs(AllocNameBuf); + + const MemRegion *MR = ArgVal.getAsRegion(); + assert(MR && "Only MemRegion based symbols can have offset free errors"); + + RegionOffset Offset = MR->getAsOffset(); + assert((Offset.isValid() && + !Offset.hasSymbolicOffset() && + Offset.getOffset() != 0) && + "Only symbols with a valid offset can have offset free errors"); + + int offsetBytes = Offset.getOffset() / C.getASTContext().getCharWidth(); + + os << "Argument to "; + if (!printAllocDeallocName(os, C, DeallocExpr)) + os << "deallocator"; + os << " is offset by " + << offsetBytes + << " " + << ((abs(offsetBytes) > 1) ? "bytes" : "byte") + << " from the start of "; + if (AllocExpr && printAllocDeallocName(AllocNameOs, C, AllocExpr)) + os << "memory allocated by " << AllocNameOs.str(); + else + os << "allocated memory"; + + BugReport *R = new BugReport(*BT_OffsetFree, os.str(), N); + R->markInteresting(MR->getBaseRegion()); + R->addRange(Range); + C.emitReport(R); +} + +void MallocChecker::ReportUseAfterFree(CheckerContext &C, SourceRange Range, + SymbolRef Sym) const { + + if (!Filter.CMallocOptimistic && !Filter.CMallocPessimistic && + !Filter.CNewDeleteChecker) + return; + + if (!isTrackedFamily(C, Sym)) + return; + + if (ExplodedNode *N = C.generateSink()) { + if (!BT_UseFree) + BT_UseFree.reset(new BugType("Use-after-free", "Memory Error")); + + BugReport *R = new BugReport(*BT_UseFree, + "Use of memory after it is freed", N); + + R->markInteresting(Sym); + R->addRange(Range); + R->addVisitor(new MallocBugVisitor(Sym)); + C.emitReport(R); + } +} + +void MallocChecker::ReportDoubleFree(CheckerContext &C, SourceRange Range, + bool Released, SymbolRef Sym, + SymbolRef PrevSym) const { + + if (!Filter.CMallocOptimistic && !Filter.CMallocPessimistic && + !Filter.CNewDeleteChecker) + return; + + if (!isTrackedFamily(C, Sym)) + return; + + if (ExplodedNode *N = C.generateSink()) { + if (!BT_DoubleFree) + BT_DoubleFree.reset(new BugType("Double free", "Memory Error")); + + BugReport *R = new BugReport(*BT_DoubleFree, + (Released ? "Attempt to free released memory" + : "Attempt to free non-owned memory"), + N); + R->addRange(Range); + R->markInteresting(Sym); + if (PrevSym) + R->markInteresting(PrevSym); + R->addVisitor(new MallocBugVisitor(Sym)); C.emitReport(R); } } @@ -893,9 +1386,9 @@ ProgramStateRef MallocChecker::ReallocMem(CheckerContext &C, const Expr *arg0Expr = CE->getArg(0); const LocationContext *LCtx = C.getLocationContext(); SVal Arg0Val = state->getSVal(arg0Expr, LCtx); - if (!isa<DefinedOrUnknownSVal>(Arg0Val)) + if (!Arg0Val.getAs<DefinedOrUnknownSVal>()) return 0; - DefinedOrUnknownSVal arg0Val = cast<DefinedOrUnknownSVal>(Arg0Val); + DefinedOrUnknownSVal arg0Val = Arg0Val.castAs<DefinedOrUnknownSVal>(); SValBuilder &svalBuilder = C.getSValBuilder(); @@ -909,9 +1402,9 @@ ProgramStateRef MallocChecker::ReallocMem(CheckerContext &C, // Get the value of the size argument. SVal Arg1ValG = state->getSVal(Arg1, LCtx); - if (!isa<DefinedOrUnknownSVal>(Arg1ValG)) + if (!Arg1ValG.getAs<DefinedOrUnknownSVal>()) return 0; - DefinedOrUnknownSVal Arg1Val = cast<DefinedOrUnknownSVal>(Arg1ValG); + DefinedOrUnknownSVal Arg1Val = Arg1ValG.castAs<DefinedOrUnknownSVal>(); // Compare the size argument to 0. DefinedOrUnknownSVal SizeZero = @@ -1032,18 +1525,19 @@ MallocChecker::getAllocationSite(const ExplodedNode *N, SymbolRef Sym, N = N->pred_empty() ? NULL : *(N->pred_begin()); } - ProgramPoint P = AllocNode->getLocation(); - const Stmt *AllocationStmt = 0; - if (CallExitEnd *Exit = dyn_cast<CallExitEnd>(&P)) - AllocationStmt = Exit->getCalleeContext()->getCallSite(); - else if (StmtPoint *SP = dyn_cast<StmtPoint>(&P)) - AllocationStmt = SP->getStmt(); - - return LeakInfo(AllocationStmt, ReferenceRegion); + return LeakInfo(AllocNode, ReferenceRegion); } void MallocChecker::reportLeak(SymbolRef Sym, ExplodedNode *N, CheckerContext &C) const { + + if (!Filter.CMallocOptimistic && !Filter.CMallocPessimistic && + !Filter.CNewDeleteChecker) + return; + + if (!isTrackedFamily(C, Sym)) + return; + assert(N); if (!BT_Leak) { BT_Leak.reset(new BugType("Memory leak", "Memory Error")); @@ -1059,12 +1553,20 @@ void MallocChecker::reportLeak(SymbolRef Sym, ExplodedNode *N, // With leaks, we want to unique them by the location where they were // allocated, and only report a single path. PathDiagnosticLocation LocUsedForUniqueing; - const Stmt *AllocStmt = 0; + const ExplodedNode *AllocNode = 0; const MemRegion *Region = 0; - llvm::tie(AllocStmt, Region) = getAllocationSite(N, Sym, C); - if (AllocStmt) - LocUsedForUniqueing = PathDiagnosticLocation::createBegin(AllocStmt, - C.getSourceManager(), N->getLocationContext()); + llvm::tie(AllocNode, Region) = getAllocationSite(N, Sym, C); + + ProgramPoint P = AllocNode->getLocation(); + const Stmt *AllocationStmt = 0; + if (Optional<CallExitEnd> Exit = P.getAs<CallExitEnd>()) + AllocationStmt = Exit->getCalleeContext()->getCallSite(); + else if (Optional<StmtPoint> SP = P.getAs<StmtPoint>()) + AllocationStmt = SP->getStmt(); + if (AllocationStmt) + LocUsedForUniqueing = PathDiagnosticLocation::createBegin(AllocationStmt, + C.getSourceManager(), + AllocNode->getLocationContext()); SmallString<200> buf; llvm::raw_svector_ostream os(buf); @@ -1075,7 +1577,9 @@ void MallocChecker::reportLeak(SymbolRef Sym, ExplodedNode *N, os << '\''; } - BugReport *R = new BugReport(*BT_Leak, os.str(), N, LocUsedForUniqueing); + BugReport *R = new BugReport(*BT_Leak, os.str(), N, + LocUsedForUniqueing, + AllocNode->getLocationContext()->getDecl()); R->markInteresting(Sym); R->addVisitor(new MallocBugVisitor(Sym, true)); C.emitReport(R); @@ -1091,7 +1595,7 @@ void MallocChecker::checkDeadSymbols(SymbolReaper &SymReaper, RegionStateTy RS = state->get<RegionState>(); RegionStateTy::Factory &F = state->get_context<RegionState>(); - llvm::SmallVector<SymbolRef, 2> Errors; + SmallVector<SymbolRef, 2> Errors; for (RegionStateTy::iterator I = RS.begin(), E = RS.end(); I != E; ++I) { if (SymReaper.isDead(I->first)) { if (I->second.isAllocated()) @@ -1125,7 +1629,7 @@ void MallocChecker::checkDeadSymbols(SymbolReaper &SymReaper, if (!Errors.empty()) { static SimpleProgramPointTag Tag("MallocChecker : DeadSymbolsLeak"); N = C.addTransition(C.getState(), C.getPredecessor(), &Tag); - for (llvm::SmallVector<SymbolRef, 2>::iterator + for (SmallVector<SymbolRef, 2>::iterator I = Errors.begin(), E = Errors.end(); I != E; ++I) { reportLeak(*I, N, C); } @@ -1134,27 +1638,14 @@ void MallocChecker::checkDeadSymbols(SymbolReaper &SymReaper, C.addTransition(state->set<RegionState>(RS), N); } -void MallocChecker::checkEndPath(CheckerContext &C) const { - ProgramStateRef state = C.getState(); - RegionStateTy M = state->get<RegionState>(); - - // If inside inlined call, skip it. - if (C.getLocationContext()->getParent() != 0) - return; - - for (RegionStateTy::iterator I = M.begin(), E = M.end(); I != E; ++I) { - RefState RS = I->second; - if (RS.isAllocated()) { - ExplodedNode *N = C.addTransition(state); - if (N) - reportLeak(I->first, N, C); - } - } -} - void MallocChecker::checkPreStmt(const CallExpr *CE, CheckerContext &C) const { // We will check for double free in the post visit. - if (isFreeFunction(C.getCalleeDecl(CE), C.getASTContext())) + if ((Filter.CMallocOptimistic || Filter.CMallocPessimistic) && + isFreeFunction(C.getCalleeDecl(CE), C.getASTContext())) + return; + + if (Filter.CNewDeleteChecker && + isStandardNewDelete(C.getCalleeDecl(CE), C.getASTContext())) return; // Check use after free, when a freed pointer is passed to a call. @@ -1163,7 +1654,7 @@ void MallocChecker::checkPreStmt(const CallExpr *CE, CheckerContext &C) const { E = CE->arg_end(); I != E; ++I) { const Expr *A = *I; if (A->getType().getTypePtr()->isAnyPointerType()) { - SymbolRef Sym = State->getSVal(A, C.getLocationContext()).getAsSymbol(); + SymbolRef Sym = C.getSVal(A).getAsSymbol(); if (!Sym) continue; if (checkUseAfterFree(Sym, C, A)) @@ -1193,15 +1684,7 @@ void MallocChecker::checkPreStmt(const ReturnStmt *S, CheckerContext &C) const { // Check if we are returning freed memory. if (Sym) - if (checkUseAfterFree(Sym, C, E)) - return; - - // If this function body is not inlined, stop tracking any returned symbols. - if (C.getLocationContext()->getParent() == 0) { - State = - State->scanReachableSymbols<StopTrackingCallback>(RetVal).getState(); - C.addTransition(State); - } + checkUseAfterFree(Sym, C, E); } // TODO: Blocks should be either inlined or should call invalidate regions @@ -1231,7 +1714,7 @@ void MallocChecker::checkPostStmt(const BlockExpr *BE, MemRegionManager &MemMgr = C.getSValBuilder().getRegionManager(); for ( ; I != E; ++I) { - const VarRegion *VR = *I; + const VarRegion *VR = I.getCapturedRegion(); if (VR->getSuperRegion() == R) { VR = MemMgr.getVarRegion(VR->getDecl(), LC); } @@ -1252,21 +1735,12 @@ bool MallocChecker::isReleased(SymbolRef Sym, CheckerContext &C) const { bool MallocChecker::checkUseAfterFree(SymbolRef Sym, CheckerContext &C, const Stmt *S) const { + if (isReleased(Sym, C)) { - if (ExplodedNode *N = C.generateSink()) { - if (!BT_UseFree) - BT_UseFree.reset(new BugType("Use-after-free", "Memory Error")); - - BugReport *R = new BugReport(*BT_UseFree, - "Use of memory after it is freed",N); - if (S) - R->addRange(S->getSourceRange()); - R->markInteresting(Sym); - R->addVisitor(new MallocBugVisitor(Sym)); - C.emitReport(R); - return true; - } + ReportUseAfterFree(C, S->getSourceRange(), Sym); + return true; } + return false; } @@ -1278,51 +1752,6 @@ void MallocChecker::checkLocation(SVal l, bool isLoad, const Stmt *S, checkUseAfterFree(Sym, C, S); } -//===----------------------------------------------------------------------===// -// Check various ways a symbol can be invalidated. -// TODO: This logic (the next 3 functions) is copied/similar to the -// RetainRelease checker. We might want to factor this out. -//===----------------------------------------------------------------------===// - -// Stop tracking symbols when a value escapes as a result of checkBind. -// A value escapes in three possible cases: -// (1) we are binding to something that is not a memory region. -// (2) we are binding to a memregion that does not have stack storage -// (3) we are binding to a memregion with stack storage that the store -// does not understand. -void MallocChecker::checkBind(SVal loc, SVal val, const Stmt *S, - CheckerContext &C) const { - // Are we storing to something that causes the value to "escape"? - bool escapes = true; - ProgramStateRef state = C.getState(); - - if (loc::MemRegionVal *regionLoc = dyn_cast<loc::MemRegionVal>(&loc)) { - escapes = !regionLoc->getRegion()->hasStackStorage(); - - if (!escapes) { - // To test (3), generate a new state with the binding added. If it is - // the same state, then it escapes (since the store cannot represent - // the binding). - // Do this only if we know that the store is not supposed to generate the - // same state. - SVal StoredVal = state->getSVal(regionLoc->getRegion()); - if (StoredVal != val) - escapes = (state == (state->bindLoc(*regionLoc, val))); - } - } - - // If our store can represent the binding and we aren't storing to something - // that doesn't have local storage then just return and have the simulation - // state continue as is. - if (!escapes) - return; - - // Otherwise, find all symbols referenced by 'val' that we are tracking - // and stop tracking them. - state = state->scanReachableSymbols<StopTrackingCallback>(val).getState(); - C.addTransition(state); -} - // If a symbolic region is assumed to NULL (or another constant), stop tracking // it - assuming that allocation failed on this path. ProgramStateRef MallocChecker::evalAssume(ProgramStateRef state, @@ -1352,7 +1781,7 @@ ProgramStateRef MallocChecker::evalAssume(ProgramStateRef state, if (RS->isReleased()) { if (I.getData().Kind == RPToBeFreedAfterFailure) state = state->set<RegionState>(ReallocSym, - RefState::getAllocated(RS->getStmt())); + RefState::getAllocated(RS->getAllocationFamily(), RS->getStmt())); else if (I.getData().Kind == RPDoNotTrackAfterFailure) state = state->remove<RegionState>(ReallocSym); else @@ -1365,12 +1794,8 @@ ProgramStateRef MallocChecker::evalAssume(ProgramStateRef state, return state; } -// Check if the function is known to us. So, for example, we could -// conservatively assume it can free/reallocate its pointer arguments. -// (We assume that the pointers cannot escape through calls to system -// functions not handled by this checker.) -bool MallocChecker::doesNotFreeMemory(const CallEvent *Call, - ProgramStateRef State) const { +bool MallocChecker::doesNotFreeMemOrInteresting(const CallEvent *Call, + ProgramStateRef State) const { assert(Call); // For now, assume that any C++ call can free memory. @@ -1387,24 +1812,23 @@ bool MallocChecker::doesNotFreeMemory(const CallEvent *Call, if (!Call->isInSystemHeader() || Call->hasNonZeroCallbackArg()) return false; - Selector S = Msg->getSelector(); - - // Whitelist the ObjC methods which do free memory. - // - Anything containing 'freeWhenDone' param set to 1. - // Ex: dataWithBytesNoCopy:length:freeWhenDone. - for (unsigned i = 1; i < S.getNumArgs(); ++i) { - if (S.getNameForSlot(i).equals("freeWhenDone")) { - if (Call->getArgSVal(i).isConstant(1)) - return false; - else - return true; - } - } + // If it's a method we know about, handle it explicitly post-call. + // This should happen before the "freeWhenDone" check below. + if (isKnownDeallocObjCMethodName(*Msg)) + return true; - // If the first selector ends with NoCopy, assume that the ownership is - // transferred as well. - // Ex: [NSData dataWithBytesNoCopy:bytes length:10]; - StringRef FirstSlot = S.getNameForSlot(0); + // If there's a "freeWhenDone" parameter, but the method isn't one we know + // about, we can't be sure that the object will use free() to deallocate the + // memory, so we can't model it explicitly. The best we can do is use it to + // decide whether the pointer escapes. + if (Optional<bool> FreeWhenDone = getFreeWhenDoneArg(*Msg)) + return !*FreeWhenDone; + + // If the first selector piece ends with "NoCopy", and there is no + // "freeWhenDone" parameter set to zero, we know ownership is being + // transferred. Again, though, we can't be sure that the object will use + // free() to deallocate the memory, so we can't model it explicitly. + StringRef FirstSlot = Msg->getSelector().getNameForSlot(0); if (FirstSlot.endswith("NoCopy")) return false; @@ -1509,41 +1933,50 @@ bool MallocChecker::doesNotFreeMemory(const CallEvent *Call, return true; } -// If the symbol we are tracking is invalidated, but not explicitly (ex: the &p -// escapes, when we are tracking p), do not track the symbol as we cannot reason -// about it anymore. -ProgramStateRef -MallocChecker::checkRegionChanges(ProgramStateRef State, - const StoreManager::InvalidatedSymbols *invalidated, - ArrayRef<const MemRegion *> ExplicitRegions, - ArrayRef<const MemRegion *> Regions, - const CallEvent *Call) const { - if (!invalidated || invalidated->empty()) - return State; - llvm::SmallPtrSet<SymbolRef, 8> WhitelistedSymbols; +static bool retTrue(const RefState *RS) { + return true; +} - // If it's a call which might free or reallocate memory, we assume that all - // regions (explicit and implicit) escaped. +static bool checkIfNewOrNewArrayFamily(const RefState *RS) { + return (RS->getAllocationFamily() == AF_CXXNewArray || + RS->getAllocationFamily() == AF_CXXNew); +} - // Otherwise, whitelist explicit pointers; we still can track them. - if (!Call || doesNotFreeMemory(Call, State)) { - for (ArrayRef<const MemRegion *>::iterator I = ExplicitRegions.begin(), - E = ExplicitRegions.end(); I != E; ++I) { - if (const SymbolicRegion *R = (*I)->StripCasts()->getAs<SymbolicRegion>()) - WhitelistedSymbols.insert(R->getSymbol()); - } +ProgramStateRef MallocChecker::checkPointerEscape(ProgramStateRef State, + const InvalidatedSymbols &Escaped, + const CallEvent *Call, + PointerEscapeKind Kind) const { + return checkPointerEscapeAux(State, Escaped, Call, Kind, &retTrue); +} + +ProgramStateRef MallocChecker::checkConstPointerEscape(ProgramStateRef State, + const InvalidatedSymbols &Escaped, + const CallEvent *Call, + PointerEscapeKind Kind) const { + return checkPointerEscapeAux(State, Escaped, Call, Kind, + &checkIfNewOrNewArrayFamily); +} + +ProgramStateRef MallocChecker::checkPointerEscapeAux(ProgramStateRef State, + const InvalidatedSymbols &Escaped, + const CallEvent *Call, + PointerEscapeKind Kind, + bool(*CheckRefState)(const RefState*)) const { + // If we know that the call does not free memory, or we want to process the + // call later, keep tracking the top level arguments. + if ((Kind == PSK_DirectEscapeOnCall || + Kind == PSK_IndirectEscapeOnCall) && + doesNotFreeMemOrInteresting(Call, State)) { + return State; } - for (StoreManager::InvalidatedSymbols::const_iterator I=invalidated->begin(), - E = invalidated->end(); I!=E; ++I) { + for (InvalidatedSymbols::const_iterator I = Escaped.begin(), + E = Escaped.end(); + I != E; ++I) { SymbolRef sym = *I; - if (WhitelistedSymbols.count(sym)) - continue; - // The symbol escaped. Note, we assume that if the symbol is released, - // passing it out will result in a use after free. We also keep tracking - // relinquished symbols. + if (const RefState *RS = State->get<RegionState>(sym)) { - if (RS->isAllocated()) + if (RS->isAllocated() && CheckRefState(RS)) State = State->remove<RegionState>(sym); } } @@ -1584,16 +2017,16 @@ MallocChecker::MallocBugVisitor::VisitNode(const ExplodedNode *N, // Retrieve the associated statement. ProgramPoint ProgLoc = N->getLocation(); - if (StmtPoint *SP = dyn_cast<StmtPoint>(&ProgLoc)) + if (Optional<StmtPoint> SP = ProgLoc.getAs<StmtPoint>()) { S = SP->getStmt(); - else if (CallExitEnd *Exit = dyn_cast<CallExitEnd>(&ProgLoc)) + } else if (Optional<CallExitEnd> Exit = ProgLoc.getAs<CallExitEnd>()) { S = Exit->getCalleeContext()->getCallSite(); - // If an assumption was made on a branch, it should be caught - // here by looking at the state transition. - else if (BlockEdge *Edge = dyn_cast<BlockEdge>(&ProgLoc)) { - const CFGBlock *srcBlk = Edge->getSrc(); - S = srcBlk->getTerminator(); + } else if (Optional<BlockEdge> Edge = ProgLoc.getAs<BlockEdge>()) { + // If an assumption was made on a branch, it should be caught + // here by looking at the state transition. + S = Edge->getSrc()->getTerminator(); } + if (!S) return 0; @@ -1658,8 +2091,15 @@ void MallocChecker::printState(raw_ostream &Out, ProgramStateRef State, RegionStateTy RS = State->get<RegionState>(); - if (!RS.isEmpty()) - Out << "Has Malloc data" << NL; + if (!RS.isEmpty()) { + Out << Sep << "MallocChecker:" << NL; + for (RegionStateTy::iterator I = RS.begin(), E = RS.end(); I != E; ++I) { + I.getKey()->dumpToStream(Out); + Out << " : "; + I.getData().dump(Out); + Out << NL; + } + } } #define REGISTER_CHECKER(name) \ @@ -1670,3 +2110,5 @@ void ento::register##name(CheckerManager &mgr) {\ REGISTER_CHECKER(MallocPessimistic) REGISTER_CHECKER(MallocOptimistic) +REGISTER_CHECKER(NewDeleteChecker) +REGISTER_CHECKER(MismatchedDeallocatorChecker) |