MacOSKeychainAPIChecker.cpp revision 76aadc346c3a4c363238a1e1232f324c3355d9e0
1//==--- MacOSKeychainAPIChecker.cpp ------------------------------*- C++ -*-==// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// This checker flags misuses of KeyChainAPI. In particular, the password data 10// allocated/returned by SecKeychainItemCopyContent, 11// SecKeychainFindGenericPassword, SecKeychainFindInternetPassword functions has 12// to be freed using a call to SecKeychainItemFreeContent. 13//===----------------------------------------------------------------------===// 14 15#include "ClangSACheckers.h" 16#include "clang/StaticAnalyzer/Core/Checker.h" 17#include "clang/StaticAnalyzer/Core/CheckerManager.h" 18#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 19#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" 20#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" 21#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h" 22#include "llvm/ADT/SmallString.h" 23 24using namespace clang; 25using namespace ento; 26 27namespace { 28class MacOSKeychainAPIChecker : public Checker<check::PreStmt<CallExpr>, 29 check::PreStmt<ReturnStmt>, 30 check::PostStmt<CallExpr>, 31 check::EndPath, 32 check::DeadSymbols> { 33 mutable OwningPtr<BugType> BT; 34 35public: 36 /// AllocationState is a part of the checker specific state together with the 37 /// MemRegion corresponding to the allocated data. 38 struct AllocationState { 39 /// The index of the allocator function. 40 unsigned int AllocatorIdx; 41 SymbolRef Region; 42 43 AllocationState(const Expr *E, unsigned int Idx, SymbolRef R) : 44 AllocatorIdx(Idx), 45 Region(R) {} 46 47 bool operator==(const AllocationState &X) const { 48 return (AllocatorIdx == X.AllocatorIdx && 49 Region == X.Region); 50 } 51 52 void Profile(llvm::FoldingSetNodeID &ID) const { 53 ID.AddInteger(AllocatorIdx); 54 ID.AddPointer(Region); 55 } 56 }; 57 58 void checkPreStmt(const CallExpr *S, CheckerContext &C) const; 59 void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const; 60 void checkPostStmt(const CallExpr *S, CheckerContext &C) const; 61 void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const; 62 void checkEndPath(CheckerContext &C) const; 63 64private: 65 typedef std::pair<SymbolRef, const AllocationState*> AllocationPair; 66 typedef llvm::SmallVector<AllocationPair, 2> AllocationPairVec; 67 68 enum APIKind { 69 /// Denotes functions tracked by this checker. 70 ValidAPI = 0, 71 /// The functions commonly/mistakenly used in place of the given API. 72 ErrorAPI = 1, 73 /// The functions which may allocate the data. These are tracked to reduce 74 /// the false alarm rate. 75 PossibleAPI = 2 76 }; 77 /// Stores the information about the allocator and deallocator functions - 78 /// these are the functions the checker is tracking. 79 struct ADFunctionInfo { 80 const char* Name; 81 unsigned int Param; 82 unsigned int DeallocatorIdx; 83 APIKind Kind; 84 }; 85 static const unsigned InvalidIdx = 100000; 86 static const unsigned FunctionsToTrackSize = 8; 87 static const ADFunctionInfo FunctionsToTrack[FunctionsToTrackSize]; 88 /// The value, which represents no error return value for allocator functions. 89 static const unsigned NoErr = 0; 90 91 /// Given the function name, returns the index of the allocator/deallocator 92 /// function. 93 static unsigned getTrackedFunctionIndex(StringRef Name, bool IsAllocator); 94 95 inline void initBugType() const { 96 if (!BT) 97 BT.reset(new BugType("Improper use of SecKeychain API", "Mac OS API")); 98 } 99 100 void generateDeallocatorMismatchReport(const AllocationPair &AP, 101 const Expr *ArgExpr, 102 CheckerContext &C) const; 103 104 /// Find the allocation site for Sym on the path leading to the node N. 105 const Stmt *getAllocationSite(const ExplodedNode *N, SymbolRef Sym, 106 CheckerContext &C) const; 107 108 BugReport *generateAllocatedDataNotReleasedReport(const AllocationPair &AP, 109 ExplodedNode *N, 110 CheckerContext &C) const; 111 112 /// Check if RetSym evaluates to an error value in the current state. 113 bool definitelyReturnedError(SymbolRef RetSym, 114 ProgramStateRef State, 115 SValBuilder &Builder, 116 bool noError = false) const; 117 118 /// Check if RetSym evaluates to a NoErr value in the current state. 119 bool definitelyDidnotReturnError(SymbolRef RetSym, 120 ProgramStateRef State, 121 SValBuilder &Builder) const { 122 return definitelyReturnedError(RetSym, State, Builder, true); 123 } 124 125 /// Mark an AllocationPair interesting for diagnostic reporting. 126 void markInteresting(BugReport *R, const AllocationPair &AP) const { 127 R->markInteresting(AP.first); 128 R->markInteresting(AP.second->Region); 129 } 130 131 /// The bug visitor which allows us to print extra diagnostics along the 132 /// BugReport path. For example, showing the allocation site of the leaked 133 /// region. 134 class SecKeychainBugVisitor : public BugReporterVisitor { 135 protected: 136 // The allocated region symbol tracked by the main analysis. 137 SymbolRef Sym; 138 139 public: 140 SecKeychainBugVisitor(SymbolRef S) : Sym(S) {} 141 virtual ~SecKeychainBugVisitor() {} 142 143 void Profile(llvm::FoldingSetNodeID &ID) const { 144 static int X = 0; 145 ID.AddPointer(&X); 146 ID.AddPointer(Sym); 147 } 148 149 PathDiagnosticPiece *VisitNode(const ExplodedNode *N, 150 const ExplodedNode *PrevN, 151 BugReporterContext &BRC, 152 BugReport &BR); 153 }; 154}; 155} 156 157/// ProgramState traits to store the currently allocated (and not yet freed) 158/// symbols. This is a map from the allocated content symbol to the 159/// corresponding AllocationState. 160typedef llvm::ImmutableMap<SymbolRef, 161 MacOSKeychainAPIChecker::AllocationState> AllocatedSetTy; 162 163namespace { struct AllocatedData {}; } 164namespace clang { namespace ento { 165template<> struct ProgramStateTrait<AllocatedData> 166 : public ProgramStatePartialTrait<AllocatedSetTy > { 167 static void *GDMIndex() { static int index = 0; return &index; } 168}; 169}} 170 171static bool isEnclosingFunctionParam(const Expr *E) { 172 E = E->IgnoreParenCasts(); 173 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { 174 const ValueDecl *VD = DRE->getDecl(); 175 if (isa<ImplicitParamDecl>(VD) || isa<ParmVarDecl>(VD)) 176 return true; 177 } 178 return false; 179} 180 181const MacOSKeychainAPIChecker::ADFunctionInfo 182 MacOSKeychainAPIChecker::FunctionsToTrack[FunctionsToTrackSize] = { 183 {"SecKeychainItemCopyContent", 4, 3, ValidAPI}, // 0 184 {"SecKeychainFindGenericPassword", 6, 3, ValidAPI}, // 1 185 {"SecKeychainFindInternetPassword", 13, 3, ValidAPI}, // 2 186 {"SecKeychainItemFreeContent", 1, InvalidIdx, ValidAPI}, // 3 187 {"SecKeychainItemCopyAttributesAndData", 5, 5, ValidAPI}, // 4 188 {"SecKeychainItemFreeAttributesAndData", 1, InvalidIdx, ValidAPI}, // 5 189 {"free", 0, InvalidIdx, ErrorAPI}, // 6 190 {"CFStringCreateWithBytesNoCopy", 1, InvalidIdx, PossibleAPI}, // 7 191}; 192 193unsigned MacOSKeychainAPIChecker::getTrackedFunctionIndex(StringRef Name, 194 bool IsAllocator) { 195 for (unsigned I = 0; I < FunctionsToTrackSize; ++I) { 196 ADFunctionInfo FI = FunctionsToTrack[I]; 197 if (FI.Name != Name) 198 continue; 199 // Make sure the function is of the right type (allocator vs deallocator). 200 if (IsAllocator && (FI.DeallocatorIdx == InvalidIdx)) 201 return InvalidIdx; 202 if (!IsAllocator && (FI.DeallocatorIdx != InvalidIdx)) 203 return InvalidIdx; 204 205 return I; 206 } 207 // The function is not tracked. 208 return InvalidIdx; 209} 210 211static SymbolRef getSymbolForRegion(CheckerContext &C, 212 const MemRegion *R) { 213 // Implicit casts (ex: void* -> char*) can turn Symbolic region into element 214 // region, if that is the case, get the underlining region. 215 R = R->StripCasts(); 216 if (!isa<SymbolicRegion>(R)) { 217 return 0; 218 } 219 return cast<SymbolicRegion>(R)->getSymbol(); 220} 221 222static bool isBadDeallocationArgument(const MemRegion *Arg) { 223 if (isa<AllocaRegion>(Arg) || 224 isa<BlockDataRegion>(Arg) || 225 isa<TypedRegion>(Arg)) { 226 return true; 227 } 228 return false; 229} 230/// Given the address expression, retrieve the value it's pointing to. Assume 231/// that value is itself an address, and return the corresponding symbol. 232static SymbolRef getAsPointeeSymbol(const Expr *Expr, 233 CheckerContext &C) { 234 ProgramStateRef State = C.getState(); 235 SVal ArgV = State->getSVal(Expr, C.getLocationContext()); 236 237 if (const loc::MemRegionVal *X = dyn_cast<loc::MemRegionVal>(&ArgV)) { 238 StoreManager& SM = C.getStoreManager(); 239 const MemRegion *V = SM.getBinding(State->getStore(), *X).getAsRegion(); 240 if (V) 241 return getSymbolForRegion(C, V); 242 } 243 return 0; 244} 245 246// When checking for error code, we need to consider the following cases: 247// 1) noErr / [0] 248// 2) someErr / [1, inf] 249// 3) unknown 250// If noError, returns true iff (1). 251// If !noError, returns true iff (2). 252bool MacOSKeychainAPIChecker::definitelyReturnedError(SymbolRef RetSym, 253 ProgramStateRef State, 254 SValBuilder &Builder, 255 bool noError) const { 256 DefinedOrUnknownSVal NoErrVal = Builder.makeIntVal(NoErr, 257 Builder.getSymbolManager().getType(RetSym)); 258 DefinedOrUnknownSVal NoErr = Builder.evalEQ(State, NoErrVal, 259 nonloc::SymbolVal(RetSym)); 260 ProgramStateRef ErrState = State->assume(NoErr, noError); 261 if (ErrState == State) { 262 return true; 263 } 264 265 return false; 266} 267 268// Report deallocator mismatch. Remove the region from tracking - reporting a 269// missing free error after this one is redundant. 270void MacOSKeychainAPIChecker:: 271 generateDeallocatorMismatchReport(const AllocationPair &AP, 272 const Expr *ArgExpr, 273 CheckerContext &C) const { 274 ProgramStateRef State = C.getState(); 275 State = State->remove<AllocatedData>(AP.first); 276 ExplodedNode *N = C.addTransition(State); 277 278 if (!N) 279 return; 280 initBugType(); 281 SmallString<80> sbuf; 282 llvm::raw_svector_ostream os(sbuf); 283 unsigned int PDeallocIdx = 284 FunctionsToTrack[AP.second->AllocatorIdx].DeallocatorIdx; 285 286 os << "Deallocator doesn't match the allocator: '" 287 << FunctionsToTrack[PDeallocIdx].Name << "' should be used."; 288 BugReport *Report = new BugReport(*BT, os.str(), N); 289 Report->addVisitor(new SecKeychainBugVisitor(AP.first)); 290 Report->addRange(ArgExpr->getSourceRange()); 291 markInteresting(Report, AP); 292 C.EmitReport(Report); 293} 294 295void MacOSKeychainAPIChecker::checkPreStmt(const CallExpr *CE, 296 CheckerContext &C) const { 297 unsigned idx = InvalidIdx; 298 ProgramStateRef State = C.getState(); 299 300 StringRef funName = C.getCalleeName(CE); 301 if (funName.empty()) 302 return; 303 304 // If it is a call to an allocator function, it could be a double allocation. 305 idx = getTrackedFunctionIndex(funName, true); 306 if (idx != InvalidIdx) { 307 const Expr *ArgExpr = CE->getArg(FunctionsToTrack[idx].Param); 308 if (SymbolRef V = getAsPointeeSymbol(ArgExpr, C)) 309 if (const AllocationState *AS = State->get<AllocatedData>(V)) { 310 if (!definitelyReturnedError(AS->Region, State, C.getSValBuilder())) { 311 // Remove the value from the state. The new symbol will be added for 312 // tracking when the second allocator is processed in checkPostStmt(). 313 State = State->remove<AllocatedData>(V); 314 ExplodedNode *N = C.addTransition(State); 315 if (!N) 316 return; 317 initBugType(); 318 SmallString<128> sbuf; 319 llvm::raw_svector_ostream os(sbuf); 320 unsigned int DIdx = FunctionsToTrack[AS->AllocatorIdx].DeallocatorIdx; 321 os << "Allocated data should be released before another call to " 322 << "the allocator: missing a call to '" 323 << FunctionsToTrack[DIdx].Name 324 << "'."; 325 BugReport *Report = new BugReport(*BT, os.str(), N); 326 Report->addVisitor(new SecKeychainBugVisitor(V)); 327 Report->addRange(ArgExpr->getSourceRange()); 328 Report->markInteresting(AS->Region); 329 C.EmitReport(Report); 330 } 331 } 332 return; 333 } 334 335 // Is it a call to one of deallocator functions? 336 idx = getTrackedFunctionIndex(funName, false); 337 if (idx == InvalidIdx) 338 return; 339 340 // Check the argument to the deallocator. 341 const Expr *ArgExpr = CE->getArg(FunctionsToTrack[idx].Param); 342 SVal ArgSVal = State->getSVal(ArgExpr, C.getLocationContext()); 343 344 // Undef is reported by another checker. 345 if (ArgSVal.isUndef()) 346 return; 347 348 const MemRegion *Arg = ArgSVal.getAsRegion(); 349 if (!Arg) 350 return; 351 352 SymbolRef ArgSM = getSymbolForRegion(C, Arg); 353 bool RegionArgIsBad = ArgSM ? false : isBadDeallocationArgument(Arg); 354 // If the argument is coming from the heap, globals, or unknown, do not 355 // report it. 356 if (!ArgSM && !RegionArgIsBad) 357 return; 358 359 // Is the argument to the call being tracked? 360 const AllocationState *AS = State->get<AllocatedData>(ArgSM); 361 if (!AS && FunctionsToTrack[idx].Kind != ValidAPI) { 362 return; 363 } 364 // If trying to free data which has not been allocated yet, report as a bug. 365 // TODO: We might want a more precise diagnostic for double free 366 // (that would involve tracking all the freed symbols in the checker state). 367 if (!AS || RegionArgIsBad) { 368 // It is possible that this is a false positive - the argument might 369 // have entered as an enclosing function parameter. 370 if (isEnclosingFunctionParam(ArgExpr)) 371 return; 372 373 ExplodedNode *N = C.addTransition(State); 374 if (!N) 375 return; 376 initBugType(); 377 BugReport *Report = new BugReport(*BT, 378 "Trying to free data which has not been allocated.", N); 379 Report->addRange(ArgExpr->getSourceRange()); 380 if (AS) 381 Report->markInteresting(AS->Region); 382 C.EmitReport(Report); 383 return; 384 } 385 386 // Process functions which might deallocate. 387 if (FunctionsToTrack[idx].Kind == PossibleAPI) { 388 389 if (funName == "CFStringCreateWithBytesNoCopy") { 390 const Expr *DeallocatorExpr = CE->getArg(5)->IgnoreParenCasts(); 391 // NULL ~ default deallocator, so warn. 392 if (DeallocatorExpr->isNullPointerConstant(C.getASTContext(), 393 Expr::NPC_ValueDependentIsNotNull)) { 394 const AllocationPair AP = std::make_pair(ArgSM, AS); 395 generateDeallocatorMismatchReport(AP, ArgExpr, C); 396 return; 397 } 398 // One of the default allocators, so warn. 399 if (const DeclRefExpr *DE = dyn_cast<DeclRefExpr>(DeallocatorExpr)) { 400 StringRef DeallocatorName = DE->getFoundDecl()->getName(); 401 if (DeallocatorName == "kCFAllocatorDefault" || 402 DeallocatorName == "kCFAllocatorSystemDefault" || 403 DeallocatorName == "kCFAllocatorMalloc") { 404 const AllocationPair AP = std::make_pair(ArgSM, AS); 405 generateDeallocatorMismatchReport(AP, ArgExpr, C); 406 return; 407 } 408 // If kCFAllocatorNull, which does not deallocate, we still have to 409 // find the deallocator. Otherwise, assume that the user had written a 410 // custom deallocator which does the right thing. 411 if (DE->getFoundDecl()->getName() != "kCFAllocatorNull") { 412 State = State->remove<AllocatedData>(ArgSM); 413 C.addTransition(State); 414 return; 415 } 416 } 417 } 418 return; 419 } 420 421 // The call is deallocating a value we previously allocated, so remove it 422 // from the next state. 423 State = State->remove<AllocatedData>(ArgSM); 424 425 // Check if the proper deallocator is used. 426 unsigned int PDeallocIdx = FunctionsToTrack[AS->AllocatorIdx].DeallocatorIdx; 427 if (PDeallocIdx != idx || (FunctionsToTrack[idx].Kind == ErrorAPI)) { 428 const AllocationPair AP = std::make_pair(ArgSM, AS); 429 generateDeallocatorMismatchReport(AP, ArgExpr, C); 430 return; 431 } 432 433 // If the buffer can be null and the return status can be an error, 434 // report a bad call to free. 435 if (State->assume(cast<DefinedSVal>(ArgSVal), false) && 436 !definitelyDidnotReturnError(AS->Region, State, C.getSValBuilder())) { 437 ExplodedNode *N = C.addTransition(State); 438 if (!N) 439 return; 440 initBugType(); 441 BugReport *Report = new BugReport(*BT, 442 "Only call free if a valid (non-NULL) buffer was returned.", N); 443 Report->addVisitor(new SecKeychainBugVisitor(ArgSM)); 444 Report->addRange(ArgExpr->getSourceRange()); 445 Report->markInteresting(AS->Region); 446 C.EmitReport(Report); 447 return; 448 } 449 450 C.addTransition(State); 451} 452 453void MacOSKeychainAPIChecker::checkPostStmt(const CallExpr *CE, 454 CheckerContext &C) const { 455 ProgramStateRef State = C.getState(); 456 StringRef funName = C.getCalleeName(CE); 457 458 // If a value has been allocated, add it to the set for tracking. 459 unsigned idx = getTrackedFunctionIndex(funName, true); 460 if (idx == InvalidIdx) 461 return; 462 463 const Expr *ArgExpr = CE->getArg(FunctionsToTrack[idx].Param); 464 // If the argument entered as an enclosing function parameter, skip it to 465 // avoid false positives. 466 if (isEnclosingFunctionParam(ArgExpr) && 467 C.getLocationContext()->getParent() == 0) 468 return; 469 470 if (SymbolRef V = getAsPointeeSymbol(ArgExpr, C)) { 471 // If the argument points to something that's not a symbolic region, it 472 // can be: 473 // - unknown (cannot reason about it) 474 // - undefined (already reported by other checker) 475 // - constant (null - should not be tracked, 476 // other constant will generate a compiler warning) 477 // - goto (should be reported by other checker) 478 479 // The call return value symbol should stay alive for as long as the 480 // allocated value symbol, since our diagnostics depend on the value 481 // returned by the call. Ex: Data should only be freed if noErr was 482 // returned during allocation.) 483 SymbolRef RetStatusSymbol = 484 State->getSVal(CE, C.getLocationContext()).getAsSymbol(); 485 C.getSymbolManager().addSymbolDependency(V, RetStatusSymbol); 486 487 // Track the allocated value in the checker state. 488 State = State->set<AllocatedData>(V, AllocationState(ArgExpr, idx, 489 RetStatusSymbol)); 490 assert(State); 491 C.addTransition(State); 492 } 493} 494 495void MacOSKeychainAPIChecker::checkPreStmt(const ReturnStmt *S, 496 CheckerContext &C) const { 497 const Expr *retExpr = S->getRetValue(); 498 if (!retExpr) 499 return; 500 501 // If inside inlined call, skip it. 502 if (C.getLocationContext()->getParent() != 0) 503 return; 504 505 // Check if the value is escaping through the return. 506 ProgramStateRef state = C.getState(); 507 const MemRegion *V = 508 state->getSVal(retExpr, C.getLocationContext()).getAsRegion(); 509 if (!V) 510 return; 511 state = state->remove<AllocatedData>(getSymbolForRegion(C, V)); 512 513 // Proceed from the new state. 514 C.addTransition(state); 515} 516 517// TODO: This logic is the same as in Malloc checker. 518const Stmt * 519MacOSKeychainAPIChecker::getAllocationSite(const ExplodedNode *N, 520 SymbolRef Sym, 521 CheckerContext &C) const { 522 const LocationContext *LeakContext = N->getLocationContext(); 523 // Walk the ExplodedGraph backwards and find the first node that referred to 524 // the tracked symbol. 525 const ExplodedNode *AllocNode = N; 526 527 while (N) { 528 if (!N->getState()->get<AllocatedData>(Sym)) 529 break; 530 // Allocation node, is the last node in the current context in which the 531 // symbol was tracked. 532 if (N->getLocationContext() == LeakContext) 533 AllocNode = N; 534 N = N->pred_empty() ? NULL : *(N->pred_begin()); 535 } 536 537 ProgramPoint P = AllocNode->getLocation(); 538 if (!isa<StmtPoint>(P)) 539 return 0; 540 return cast<clang::PostStmt>(P).getStmt(); 541} 542 543BugReport *MacOSKeychainAPIChecker:: 544 generateAllocatedDataNotReleasedReport(const AllocationPair &AP, 545 ExplodedNode *N, 546 CheckerContext &C) const { 547 const ADFunctionInfo &FI = FunctionsToTrack[AP.second->AllocatorIdx]; 548 initBugType(); 549 SmallString<70> sbuf; 550 llvm::raw_svector_ostream os(sbuf); 551 os << "Allocated data is not released: missing a call to '" 552 << FunctionsToTrack[FI.DeallocatorIdx].Name << "'."; 553 554 // Most bug reports are cached at the location where they occurred. 555 // With leaks, we want to unique them by the location where they were 556 // allocated, and only report a single path. 557 PathDiagnosticLocation LocUsedForUniqueing; 558 if (const Stmt *AllocStmt = getAllocationSite(N, AP.first, C)) 559 LocUsedForUniqueing = PathDiagnosticLocation::createBegin(AllocStmt, 560 C.getSourceManager(), N->getLocationContext()); 561 562 BugReport *Report = new BugReport(*BT, os.str(), N, LocUsedForUniqueing); 563 Report->addVisitor(new SecKeychainBugVisitor(AP.first)); 564 markInteresting(Report, AP); 565 return Report; 566} 567 568void MacOSKeychainAPIChecker::checkDeadSymbols(SymbolReaper &SR, 569 CheckerContext &C) const { 570 ProgramStateRef State = C.getState(); 571 AllocatedSetTy ASet = State->get<AllocatedData>(); 572 if (ASet.isEmpty()) 573 return; 574 575 bool Changed = false; 576 AllocationPairVec Errors; 577 for (AllocatedSetTy::iterator I = ASet.begin(), E = ASet.end(); I != E; ++I) { 578 if (SR.isLive(I->first)) 579 continue; 580 581 Changed = true; 582 State = State->remove<AllocatedData>(I->first); 583 // If the allocated symbol is null or if the allocation call might have 584 // returned an error, do not report. 585 if (State->getSymVal(I->first) || 586 definitelyReturnedError(I->second.Region, State, C.getSValBuilder())) 587 continue; 588 Errors.push_back(std::make_pair(I->first, &I->second)); 589 } 590 if (!Changed) { 591 // Generate the new, cleaned up state. 592 C.addTransition(State); 593 return; 594 } 595 596 static SimpleProgramPointTag Tag("MacOSKeychainAPIChecker : DeadSymbolsLeak"); 597 ExplodedNode *N = C.addTransition(C.getState(), C.getPredecessor(), &Tag); 598 599 // Generate the error reports. 600 for (AllocationPairVec::iterator I = Errors.begin(), E = Errors.end(); 601 I != E; ++I) { 602 C.EmitReport(generateAllocatedDataNotReleasedReport(*I, N, C)); 603 } 604 605 // Generate the new, cleaned up state. 606 C.addTransition(State, N); 607} 608 609// TODO: Remove this after we ensure that checkDeadSymbols are always called. 610void MacOSKeychainAPIChecker::checkEndPath(CheckerContext &C) const { 611 ProgramStateRef state = C.getState(); 612 613 // If inside inlined call, skip it. 614 if (C.getLocationContext()->getParent() != 0) 615 return; 616 617 AllocatedSetTy AS = state->get<AllocatedData>(); 618 if (AS.isEmpty()) 619 return; 620 621 // Anything which has been allocated but not freed (nor escaped) will be 622 // found here, so report it. 623 bool Changed = false; 624 AllocationPairVec Errors; 625 for (AllocatedSetTy::iterator I = AS.begin(), E = AS.end(); I != E; ++I ) { 626 Changed = true; 627 state = state->remove<AllocatedData>(I->first); 628 // If the allocated symbol is null or if error code was returned at 629 // allocation, do not report. 630 if (state->getSymVal(I.getKey()) || 631 definitelyReturnedError(I->second.Region, state, 632 C.getSValBuilder())) { 633 continue; 634 } 635 Errors.push_back(std::make_pair(I->first, &I->second)); 636 } 637 638 // If no change, do not generate a new state. 639 if (!Changed) { 640 C.addTransition(state); 641 return; 642 } 643 644 static SimpleProgramPointTag Tag("MacOSKeychainAPIChecker : EndPathLeak"); 645 ExplodedNode *N = C.addTransition(C.getState(), C.getPredecessor(), &Tag); 646 647 // Generate the error reports. 648 for (AllocationPairVec::iterator I = Errors.begin(), E = Errors.end(); 649 I != E; ++I) { 650 C.EmitReport(generateAllocatedDataNotReleasedReport(*I, N, C)); 651 } 652 653 C.addTransition(state, N); 654} 655 656 657PathDiagnosticPiece *MacOSKeychainAPIChecker::SecKeychainBugVisitor::VisitNode( 658 const ExplodedNode *N, 659 const ExplodedNode *PrevN, 660 BugReporterContext &BRC, 661 BugReport &BR) { 662 const AllocationState *AS = N->getState()->get<AllocatedData>(Sym); 663 if (!AS) 664 return 0; 665 const AllocationState *ASPrev = PrevN->getState()->get<AllocatedData>(Sym); 666 if (ASPrev) 667 return 0; 668 669 // (!ASPrev && AS) ~ We started tracking symbol in node N, it must be the 670 // allocation site. 671 const CallExpr *CE = cast<CallExpr>(cast<StmtPoint>(N->getLocation()) 672 .getStmt()); 673 const FunctionDecl *funDecl = CE->getDirectCallee(); 674 assert(funDecl && "We do not support indirect function calls as of now."); 675 StringRef funName = funDecl->getName(); 676 677 // Get the expression of the corresponding argument. 678 unsigned Idx = getTrackedFunctionIndex(funName, true); 679 assert(Idx != InvalidIdx && "This should be a call to an allocator."); 680 const Expr *ArgExpr = CE->getArg(FunctionsToTrack[Idx].Param); 681 PathDiagnosticLocation Pos(ArgExpr, BRC.getSourceManager(), 682 N->getLocationContext()); 683 return new PathDiagnosticEventPiece(Pos, "Data is allocated here."); 684} 685 686void ento::registerMacOSKeychainAPIChecker(CheckerManager &mgr) { 687 mgr.registerChecker<MacOSKeychainAPIChecker>(); 688} 689