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usr / src / contrib / llvm-project / clang / lib / StaticAnalyzer / Checkers /

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📄 AllocationState.h(1.41 KB)
📄 AnalysisOrderChecker.cpp(8.62 KB)
📄 AnalyzerStatsChecker.cpp(5.04 KB)
📄 ArrayBoundChecker.cpp(3.22 KB)
📄 ArrayBoundCheckerV2.cpp(13.07 KB)
📄 BasicObjCFoundationChecks.cpp(43.82 KB)
📄 BlockInCriticalSectionChecker.cpp(6.69 KB)
📄 BoolAssignmentChecker.cpp(3.45 KB)
📄 BuiltinFunctionChecker.cpp(5 KB)
📄 CStringChecker.cpp(93.24 KB)
📄 CStringSyntaxChecker.cpp(9.8 KB)
📄 CXXSelfAssignmentChecker.cpp(3.08 KB)
📄 CallAndMessageChecker.cpp(26.57 KB)
📄 CastSizeChecker.cpp(4.96 KB)
📄 CastToStructChecker.cpp(4.43 KB)
📄 CastValueChecker.cpp(19.65 KB)
📄 CheckObjCDealloc.cpp(37.83 KB)
📄 CheckObjCInstMethSignature.cpp(4.8 KB)
📄 CheckPlacementNew.cpp(11.91 KB)
📄 CheckSecuritySyntaxOnly.cpp(38.79 KB)
📄 CheckSizeofPointer.cpp(3.16 KB)
📄 CheckerDocumentation.cpp(14.64 KB)
📄 ChrootChecker.cpp(4.88 KB)
📄 CloneChecker.cpp(8.28 KB)
📄 ContainerModeling.cpp(39.85 KB)
📄 ConversionChecker.cpp(7.11 KB)
📄 DeadStoresChecker.cpp(17.82 KB)
📄 DebugCheckers.cpp(10.41 KB)
📄 DebugContainerModeling.cpp(4.94 KB)
📄 DebugIteratorModeling.cpp(5.15 KB)
📄 DeleteWithNonVirtualDtorChecker.cpp(5.35 KB)
📄 DereferenceChecker.cpp(10.54 KB)
📄 DirectIvarAssignment.cpp(8.02 KB)
📄 DivZeroChecker.cpp(3.42 KB)
📄 DynamicTypeChecker.cpp(7.31 KB)
📄 DynamicTypePropagation.cpp(42.11 KB)
📄 EnumCastOutOfRangeChecker.cpp(5.75 KB)
📄 ExprInspectionChecker.cpp(15.6 KB)
📄 FixedAddressChecker.cpp(2.33 KB)
📄 FuchsiaHandleChecker.cpp(23.1 KB)
📄 GCDAntipatternChecker.cpp(7.85 KB)
📄 GTestChecker.cpp(10.52 KB)
📄 GenericTaintChecker.cpp(34.31 KB)
📄 IdenticalExprChecker.cpp(18.88 KB)
📄 InnerPointerChecker.cpp(11.54 KB)
📄 InterCheckerAPI.h(1.09 KB)
📄 InvalidatedIteratorChecker.cpp(4.93 KB)
📄 Iterator.cpp(10.62 KB)
📄 Iterator.h(6.32 KB)
📄 IteratorModeling.cpp(31.33 KB)
📄 IteratorRangeChecker.cpp(12.64 KB)
📄 IvarInvalidationChecker.cpp(27.63 KB)
📄 LLVMConventionsChecker.cpp(9.9 KB)
📄 LocalizationChecker.cpp(52.38 KB)
📄 MIGChecker.cpp(11.3 KB)
📁 MPI-Checker
📄 MacOSKeychainAPIChecker.cpp(25.21 KB)
📄 MacOSXAPIChecker.cpp(6.61 KB)
📄 MallocChecker.cpp(127.38 KB)
📄 MallocOverflowSecurityChecker.cpp(11.91 KB)
📄 MallocSizeofChecker.cpp(8.03 KB)
📄 MismatchedIteratorChecker.cpp(11.01 KB)
📄 MmapWriteExecChecker.cpp(3.22 KB)
📄 Move.h(1.07 KB)
📄 MoveChecker.cpp(27 KB)
📄 NSAutoreleasePoolChecker.cpp(2.93 KB)
📄 NSErrorChecker.cpp(10.6 KB)
📄 NoReturnFunctionChecker.cpp(5.48 KB)
📄 NonNullParamChecker.cpp(11.22 KB)
📄 NonnullGlobalConstantsChecker.cpp(5.09 KB)
📄 NullabilityChecker.cpp(46.95 KB)
📄 NumberObjectConversionChecker.cpp(13.69 KB)
📄 OSObjectCStyleCast.cpp(3.14 KB)
📄 ObjCAtSyncChecker.cpp(3.34 KB)
📄 ObjCAutoreleaseWriteChecker.cpp(8.62 KB)
📄 ObjCContainersASTChecker.cpp(5.5 KB)
📄 ObjCContainersChecker.cpp(6.71 KB)
📄 ObjCMissingSuperCallChecker.cpp(9.23 KB)
📄 ObjCPropertyChecker.cpp(3.03 KB)
📄 ObjCSelfInitChecker.cpp(16.21 KB)
📄 ObjCSuperDeallocChecker.cpp(9.33 KB)
📄 ObjCUnusedIVarsChecker.cpp(6.01 KB)
📄 PaddingChecker.cpp(14.26 KB)
📄 PointerArithChecker.cpp(12.18 KB)
📄 PointerIterationChecker.cpp(3.79 KB)
📄 PointerSortingChecker.cpp(4.5 KB)
📄 PointerSubChecker.cpp(2.56 KB)
📄 PthreadLockChecker.cpp(28.42 KB)
📁 RetainCountChecker
📄 ReturnPointerRangeChecker.cpp(3.39 KB)
📄 ReturnUndefChecker.cpp(4.1 KB)
📄 ReturnValueChecker.cpp(5.79 KB)
📄 RunLoopAutoreleaseLeakChecker.cpp(7.2 KB)
📄 STLAlgorithmModeling.cpp(7 KB)
📄 SimpleStreamChecker.cpp(9.43 KB)
📄 SmartPtr.h(1.17 KB)
📄 SmartPtrChecker.cpp(2.68 KB)
📄 SmartPtrModeling.cpp(8.05 KB)
📄 StackAddrEscapeChecker.cpp(15 KB)
📄 StdLibraryFunctionsChecker.cpp(74.86 KB)
📄 StreamChecker.cpp(37.36 KB)
📄 Taint.cpp(9.04 KB)
📄 Taint.h(4.19 KB)
📄 TaintTesterChecker.cpp(2.17 KB)
📄 TestAfterDivZeroChecker.cpp(8.19 KB)
📄 TraversalChecker.cpp(4.38 KB)
📄 TrustNonnullChecker.cpp(9.12 KB)
📄 UndefBranchChecker.cpp(3.82 KB)
📄 UndefCapturedBlockVarChecker.cpp(3.64 KB)
📄 UndefResultChecker.cpp(7.19 KB)
📄 UndefinedArraySubscriptChecker.cpp(2.36 KB)
📄 UndefinedAssignmentChecker.cpp(3.74 KB)
📁 UninitializedObject
📄 UnixAPIChecker.cpp(18.05 KB)
📄 UnreachableCodeChecker.cpp(9.59 KB)
📄 VLASizeChecker.cpp(10.95 KB)
📄 ValistChecker.cpp(15.65 KB)
📄 VforkChecker.cpp(7.67 KB)
📄 VirtualCallChecker.cpp(8.11 KB)
📁 WebKit
📄 Yaml.h(2.06 KB)
📁 cert

Editing: VforkChecker.cpp

//===- VforkChecker.cpp -------- Vfork usage checks --------------*- C++ -*-==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//  This file defines vfork checker which checks for dangerous uses of vfork.
//  Vforked process shares memory (including stack) with parent so it's
//  range of actions is significantly limited: can't write variables,
//  can't call functions not in whitelist, etc. For more details, see
//  http://man7.org/linux/man-pages/man2/vfork.2.html
//
//  This checker checks for prohibited constructs in vforked process.
//  The state transition diagram:
//  PARENT ---(vfork() == 0)--> CHILD
//                                   |
//                                   --(*p = ...)--> bug
//                                   |
//                                   --foo()--> bug
//                                   |
//                                   --return--> bug
//
//===----------------------------------------------------------------------===//

#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerHelpers.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/AST/ParentMap.h"

using namespace clang;
using namespace ento;

namespace {

class VforkChecker : public Checker<check::PreCall, check::PostCall,
                                    check::Bind, check::PreStmt<ReturnStmt>> {
  mutable std::unique_ptr<BuiltinBug> BT;
  mutable llvm::SmallSet<const IdentifierInfo *, 10> VforkWhitelist;
  mutable const IdentifierInfo *II_vfork;

static bool isChildProcess(const ProgramStateRef State);

bool isVforkCall(const Decl *D, CheckerContext &C) const;
  bool isCallWhitelisted(const IdentifierInfo *II, CheckerContext &C) const;

void reportBug(const char *What, CheckerContext &C,
                 const char *Details = nullptr) const;

public:
  VforkChecker() : II_vfork(nullptr) {}

void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
  void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
  void checkBind(SVal L, SVal V, const Stmt *S, CheckerContext &C) const;
  void checkPreStmt(const ReturnStmt *RS, CheckerContext &C) const;
};

} // end anonymous namespace

// This trait holds region of variable that is assigned with vfork's
// return value (this is the only region child is allowed to write).
// VFORK_RESULT_INVALID means that we are in parent process.
// VFORK_RESULT_NONE means that vfork's return value hasn't been assigned.
// Other values point to valid regions.
REGISTER_TRAIT_WITH_PROGRAMSTATE(VforkResultRegion, const void *)
#define VFORK_RESULT_INVALID 0
#define VFORK_RESULT_NONE ((void *)(uintptr_t)1)

bool VforkChecker::isChildProcess(const ProgramStateRef State) {
  return State->get<VforkResultRegion>() != VFORK_RESULT_INVALID;
}

bool VforkChecker::isVforkCall(const Decl *D, CheckerContext &C) const {
  auto FD = dyn_cast_or_null<FunctionDecl>(D);
  if (!FD || !C.isCLibraryFunction(FD))
    return false;

if (!II_vfork) {
    ASTContext &AC = C.getASTContext();
    II_vfork = &AC.Idents.get("vfork");
  }

return FD->getIdentifier() == II_vfork;
}

// Returns true iff ok to call function after successful vfork.
bool VforkChecker::isCallWhitelisted(const IdentifierInfo *II,
                                 CheckerContext &C) const {
  if (VforkWhitelist.empty()) {
    // According to manpage.
    const char *ids[] = {
      "_Exit",
      "_exit",
      "execl",
      "execle",
      "execlp",
      "execv",
      "execve",
      "execvp",
      "execvpe",
      nullptr
    };

ASTContext &AC = C.getASTContext();
    for (const char **id = ids; *id; ++id)
      VforkWhitelist.insert(&AC.Idents.get(*id));
  }

return VforkWhitelist.count(II);
}

void VforkChecker::reportBug(const char *What, CheckerContext &C,
                             const char *Details) const {
  if (ExplodedNode *N = C.generateErrorNode(C.getState())) {
    if (!BT)
      BT.reset(new BuiltinBug(this,
                              "Dangerous construct in a vforked process"));

SmallString<256> buf;
    llvm::raw_svector_ostream os(buf);

os << What << " is prohibited after a successful vfork";

if (Details)
      os << "; " << Details;

auto Report = std::make_unique<PathSensitiveBugReport>(*BT, os.str(), N);
    // TODO: mark vfork call in BugReportVisitor
    C.emitReport(std::move(Report));
  }
}

// Detect calls to vfork and split execution appropriately.
void VforkChecker::checkPostCall(const CallEvent &Call,
                                 CheckerContext &C) const {
  // We can't call vfork in child so don't bother
  // (corresponding warning has already been emitted in checkPreCall).
  ProgramStateRef State = C.getState();
  if (isChildProcess(State))
    return;

if (!isVforkCall(Call.getDecl(), C))
    return;

// Get return value of vfork.
  SVal VforkRetVal = Call.getReturnValue();
  Optional<DefinedOrUnknownSVal> DVal =
    VforkRetVal.getAs<DefinedOrUnknownSVal>();
  if (!DVal)
    return;

// Get assigned variable.
  const ParentMap &PM = C.getLocationContext()->getParentMap();
  const Stmt *P = PM.getParentIgnoreParenCasts(Call.getOriginExpr());
  const VarDecl *LhsDecl;
  std::tie(LhsDecl, std::ignore) = parseAssignment(P);

// Get assigned memory region.
  MemRegionManager &M = C.getStoreManager().getRegionManager();
  const MemRegion *LhsDeclReg =
    LhsDecl
      ? M.getVarRegion(LhsDecl, C.getLocationContext())
      : (const MemRegion *)VFORK_RESULT_NONE;

// Parent branch gets nonzero return value (according to manpage).
  ProgramStateRef ParentState, ChildState;
  std::tie(ParentState, ChildState) = C.getState()->assume(*DVal);
  C.addTransition(ParentState);
  ChildState = ChildState->set<VforkResultRegion>(LhsDeclReg);
  C.addTransition(ChildState);
}

// Prohibit calls to non-whitelist functions in child process.
void VforkChecker::checkPreCall(const CallEvent &Call,
                                CheckerContext &C) const {
  ProgramStateRef State = C.getState();
  if (isChildProcess(State)
      && !isCallWhitelisted(Call.getCalleeIdentifier(), C))
    reportBug("This function call", C);
}

// Prohibit writes in child process (except for vfork's lhs).
void VforkChecker::checkBind(SVal L, SVal V, const Stmt *S,
                             CheckerContext &C) const {
  ProgramStateRef State = C.getState();
  if (!isChildProcess(State))
    return;

const MemRegion *VforkLhs =
    static_cast<const MemRegion *>(State->get<VforkResultRegion>());
  const MemRegion *MR = L.getAsRegion();

// Child is allowed to modify only vfork's lhs.
  if (!MR || MR == VforkLhs)
    return;

reportBug("This assignment", C);
}

// Prohibit return from function in child process.
void VforkChecker::checkPreStmt(const ReturnStmt *RS, CheckerContext &C) const {
  ProgramStateRef State = C.getState();
  if (isChildProcess(State))
    reportBug("Return", C, "call _exit() instead");
}

void ento::registerVforkChecker(CheckerManager &mgr) {
  mgr.registerChecker<VforkChecker>();
}

bool ento::shouldRegisterVforkChecker(const CheckerManager &mgr) {
  return true;
}

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