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