508 lines
18 KiB
C++
508 lines
18 KiB
C++
//=-- GRExprEngineInternalChecks.cpp - Builtin GRExprEngine Checks---*- C++ -*-=
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the BugType classes used by GRExprEngine to report
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// bugs derived from builtin checks in the path-sensitive engine.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Analysis/PathSensitive/BugReporter.h"
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#include "clang/Analysis/PathSensitive/GRExprEngine.h"
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#include "clang/Basic/SourceManager.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace clang;
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//===----------------------------------------------------------------------===//
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// Utility functions.
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//===----------------------------------------------------------------------===//
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template <typename ITERATOR> inline
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ExplodedNode<GRState>* GetNode(ITERATOR I) {
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return *I;
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}
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template <> inline
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ExplodedNode<GRState>* GetNode(GRExprEngine::undef_arg_iterator I) {
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return I->first;
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}
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//===----------------------------------------------------------------------===//
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// Bug Descriptions.
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//===----------------------------------------------------------------------===//
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namespace {
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class VISIBILITY_HIDDEN BuiltinBug : public BugType {
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GRExprEngine &Eng;
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protected:
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const std::string desc;
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public:
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BuiltinBug(GRExprEngine *eng, const char* n, const char* d)
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: BugType(n, "Logic Errors"), Eng(*eng), desc(d) {}
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BuiltinBug(GRExprEngine *eng, const char* n)
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: BugType(n, "Logic Errors"), Eng(*eng), desc(n) {}
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virtual void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) = 0;
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void FlushReports(BugReporter& BR) { FlushReportsImpl(BR, Eng); }
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template <typename ITER>
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void Emit(BugReporter& BR, ITER I, ITER E) {
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for (; I != E; ++I) BR.EmitReport(new BugReport(*this, desc.c_str(),
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GetNode(I)));
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}
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};
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class VISIBILITY_HIDDEN NullDeref : public BuiltinBug {
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public:
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NullDeref(GRExprEngine* eng)
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: BuiltinBug(eng,"Null dereference", "Dereference of null pointer") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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Emit(BR, Eng.null_derefs_begin(), Eng.null_derefs_end());
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}
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};
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class VISIBILITY_HIDDEN NilReceiverStructRet : public BugType {
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GRExprEngine &Eng;
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public:
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NilReceiverStructRet(GRExprEngine* eng) :
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BugType("'nil' receiver with struct return type", "Logic Errors"),
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Eng(*eng) {}
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void FlushReports(BugReporter& BR) {
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for (GRExprEngine::nil_receiver_struct_ret_iterator
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I=Eng.nil_receiver_struct_ret_begin(),
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E=Eng.nil_receiver_struct_ret_end(); I!=E; ++I) {
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std::string sbuf;
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llvm::raw_string_ostream os(sbuf);
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PostStmt P = cast<PostStmt>((*I)->getLocation());
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ObjCMessageExpr *ME = cast<ObjCMessageExpr>(P.getStmt());
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os << "The receiver in the message expression is 'nil' and results in the"
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" returned value (of type '"
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<< ME->getType().getAsString()
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<< "') to be garbage or otherwise undefined.";
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RangedBugReport *R = new RangedBugReport(*this, os.str().c_str(), *I);
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R->addRange(ME->getReceiver()->getSourceRange());
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BR.EmitReport(R);
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}
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}
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};
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class VISIBILITY_HIDDEN NilReceiverLargerThanVoidPtrRet : public BugType {
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GRExprEngine &Eng;
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public:
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NilReceiverLargerThanVoidPtrRet(GRExprEngine* eng) :
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BugType("'nil' receiver with return type larger than sizeof(void *)",
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"Logic Errors"),
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Eng(*eng) {}
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void FlushReports(BugReporter& BR) {
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for (GRExprEngine::nil_receiver_larger_than_voidptr_ret_iterator
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I=Eng.nil_receiver_larger_than_voidptr_ret_begin(),
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E=Eng.nil_receiver_larger_than_voidptr_ret_end(); I!=E; ++I) {
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std::string sbuf;
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llvm::raw_string_ostream os(sbuf);
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PostStmt P = cast<PostStmt>((*I)->getLocation());
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ObjCMessageExpr *ME = cast<ObjCMessageExpr>(P.getStmt());
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os << "The receiver in the message expression is 'nil' and results in the"
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" returned value (of type '"
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<< ME->getType().getAsString()
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<< "' and of size "
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<< Eng.getContext().getTypeSize(ME->getType()) / 8
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<< " bytes) to be garbage or otherwise undefined.";
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RangedBugReport *R = new RangedBugReport(*this, os.str().c_str(), *I);
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R->addRange(ME->getReceiver()->getSourceRange());
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BR.EmitReport(R);
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}
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}
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};
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class VISIBILITY_HIDDEN UndefinedDeref : public BuiltinBug {
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public:
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UndefinedDeref(GRExprEngine* eng)
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: BuiltinBug(eng,"Dereference of undefined pointer value") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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Emit(BR, Eng.undef_derefs_begin(), Eng.undef_derefs_end());
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}
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};
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class VISIBILITY_HIDDEN DivZero : public BuiltinBug {
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public:
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DivZero(GRExprEngine* eng)
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: BuiltinBug(eng,"Division-by-zero",
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"Division by zero or undefined value.") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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Emit(BR, Eng.explicit_bad_divides_begin(), Eng.explicit_bad_divides_end());
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}
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};
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class VISIBILITY_HIDDEN UndefResult : public BuiltinBug {
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public:
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UndefResult(GRExprEngine* eng) : BuiltinBug(eng,"Undefined result",
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"Result of operation is undefined.") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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Emit(BR, Eng.undef_results_begin(), Eng.undef_results_end());
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}
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};
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class VISIBILITY_HIDDEN BadCall : public BuiltinBug {
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public:
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BadCall(GRExprEngine *eng)
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: BuiltinBug(eng, "Invalid function call",
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"Called function pointer is a null or undefined pointer value") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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Emit(BR, Eng.bad_calls_begin(), Eng.bad_calls_end());
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}
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};
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class VISIBILITY_HIDDEN BadArg : public BuiltinBug {
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public:
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BadArg(GRExprEngine* eng) : BuiltinBug(eng,"Uninitialized argument",
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"Pass-by-value argument in function call is undefined.") {}
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BadArg(GRExprEngine* eng, const char* d)
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: BuiltinBug(eng,"Uninitialized argument", d) {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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for (GRExprEngine::UndefArgsTy::iterator I = Eng.undef_arg_begin(),
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E = Eng.undef_arg_end(); I!=E; ++I) {
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// Generate a report for this bug.
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RangedBugReport *report = new RangedBugReport(*this, desc.c_str(),
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I->first);
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report->addRange(I->second->getSourceRange());
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BR.EmitReport(report);
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}
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}
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};
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class VISIBILITY_HIDDEN BadMsgExprArg : public BadArg {
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public:
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BadMsgExprArg(GRExprEngine* eng)
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: BadArg(eng,"Pass-by-value argument in message expression is undefined"){}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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for (GRExprEngine::UndefArgsTy::iterator I=Eng.msg_expr_undef_arg_begin(),
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E = Eng.msg_expr_undef_arg_end(); I!=E; ++I) {
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// Generate a report for this bug.
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RangedBugReport *report = new RangedBugReport(*this, desc.c_str(),
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I->first);
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report->addRange(I->second->getSourceRange());
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BR.EmitReport(report);
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}
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}
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};
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class VISIBILITY_HIDDEN BadReceiver : public BuiltinBug {
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public:
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BadReceiver(GRExprEngine* eng)
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: BuiltinBug(eng,"Uninitialized receiver",
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"Receiver in message expression is an uninitialized value") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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for (GRExprEngine::ErrorNodes::iterator I=Eng.undef_receivers_begin(),
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End = Eng.undef_receivers_end(); I!=End; ++I) {
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// Generate a report for this bug.
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RangedBugReport *report = new RangedBugReport(*this, desc.c_str(), *I);
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ExplodedNode<GRState>* N = *I;
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Stmt *S = cast<PostStmt>(N->getLocation()).getStmt();
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Expr* E = cast<ObjCMessageExpr>(S)->getReceiver();
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assert (E && "Receiver cannot be NULL");
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report->addRange(E->getSourceRange());
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BR.EmitReport(report);
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}
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}
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};
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class VISIBILITY_HIDDEN RetStack : public BuiltinBug {
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public:
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RetStack(GRExprEngine* eng)
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: BuiltinBug(eng, "Return of address to stack-allocated memory") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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for (GRExprEngine::ret_stackaddr_iterator I=Eng.ret_stackaddr_begin(),
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End = Eng.ret_stackaddr_end(); I!=End; ++I) {
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ExplodedNode<GRState>* N = *I;
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Stmt *S = cast<PostStmt>(N->getLocation()).getStmt();
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Expr* E = cast<ReturnStmt>(S)->getRetValue();
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assert (E && "Return expression cannot be NULL");
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// Get the value associated with E.
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loc::MemRegionVal V =
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cast<loc::MemRegionVal>(Eng.getStateManager().GetSVal(N->getState(),
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E));
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// Generate a report for this bug.
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std::string buf;
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llvm::raw_string_ostream os(buf);
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SourceRange R;
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// Check if the region is a compound literal.
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if (const CompoundLiteralRegion* CR =
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dyn_cast<CompoundLiteralRegion>(V.getRegion())) {
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const CompoundLiteralExpr* CL = CR->getLiteralExpr();
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os << "Address of stack memory associated with a compound literal "
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"declared on line "
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<< BR.getSourceManager()
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.getInstantiationLineNumber(CL->getLocStart())
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<< " returned.";
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R = CL->getSourceRange();
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}
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else if (const AllocaRegion* AR = dyn_cast<AllocaRegion>(V.getRegion())) {
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const Expr* ARE = AR->getExpr();
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SourceLocation L = ARE->getLocStart();
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R = ARE->getSourceRange();
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os << "Address of stack memory allocated by call to alloca() on line "
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<< BR.getSourceManager().getInstantiationLineNumber(L)
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<< " returned.";
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}
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else {
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os << "Address of stack memory associated with local variable '"
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<< V.getRegion()->getString() << "' returned.";
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}
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RangedBugReport *report = new RangedBugReport(*this, os.str().c_str(), N);
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report->addRange(E->getSourceRange());
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if (R.isValid()) report->addRange(R);
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BR.EmitReport(report);
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}
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}
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};
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class VISIBILITY_HIDDEN RetUndef : public BuiltinBug {
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public:
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RetUndef(GRExprEngine* eng) : BuiltinBug(eng, "Uninitialized return value",
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"Uninitialized or undefined return value returned to caller.") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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Emit(BR, Eng.ret_undef_begin(), Eng.ret_undef_end());
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}
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};
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class VISIBILITY_HIDDEN UndefBranch : public BuiltinBug {
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struct VISIBILITY_HIDDEN FindUndefExpr {
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GRStateManager& VM;
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const GRState* St;
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FindUndefExpr(GRStateManager& V, const GRState* S) : VM(V), St(S) {}
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Expr* FindExpr(Expr* Ex) {
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if (!MatchesCriteria(Ex))
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return 0;
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for (Stmt::child_iterator I=Ex->child_begin(), E=Ex->child_end();I!=E;++I)
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if (Expr* ExI = dyn_cast_or_null<Expr>(*I)) {
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Expr* E2 = FindExpr(ExI);
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if (E2) return E2;
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}
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return Ex;
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}
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bool MatchesCriteria(Expr* Ex) { return VM.GetSVal(St, Ex).isUndef(); }
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};
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public:
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UndefBranch(GRExprEngine *eng)
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: BuiltinBug(eng,"Use of uninitialized value",
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"Branch condition evaluates to an uninitialized value.") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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for (GRExprEngine::undef_branch_iterator I=Eng.undef_branches_begin(),
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E=Eng.undef_branches_end(); I!=E; ++I) {
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// What's going on here: we want to highlight the subexpression of the
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// condition that is the most likely source of the "uninitialized
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// branch condition." We do a recursive walk of the condition's
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// subexpressions and roughly look for the most nested subexpression
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// that binds to Undefined. We then highlight that expression's range.
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BlockEdge B = cast<BlockEdge>((*I)->getLocation());
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Expr* Ex = cast<Expr>(B.getSrc()->getTerminatorCondition());
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assert (Ex && "Block must have a terminator.");
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// Get the predecessor node and check if is a PostStmt with the Stmt
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// being the terminator condition. We want to inspect the state
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// of that node instead because it will contain main information about
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// the subexpressions.
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assert (!(*I)->pred_empty());
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// Note: any predecessor will do. They should have identical state,
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// since all the BlockEdge did was act as an error sink since the value
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// had to already be undefined.
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ExplodedNode<GRState> *N = *(*I)->pred_begin();
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ProgramPoint P = N->getLocation();
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const GRState* St = (*I)->getState();
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if (PostStmt* PS = dyn_cast<PostStmt>(&P))
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if (PS->getStmt() == Ex)
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St = N->getState();
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FindUndefExpr FindIt(Eng.getStateManager(), St);
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Ex = FindIt.FindExpr(Ex);
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RangedBugReport *R = new RangedBugReport(*this, desc.c_str(), *I);
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R->addRange(Ex->getSourceRange());
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BR.EmitReport(R);
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}
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}
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};
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class VISIBILITY_HIDDEN OutOfBoundMemoryAccess : public BuiltinBug {
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public:
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OutOfBoundMemoryAccess(GRExprEngine* eng)
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: BuiltinBug(eng,"Out-of-bounds memory access",
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"Load or store into an out-of-bound memory position.") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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Emit(BR, Eng.explicit_oob_memacc_begin(), Eng.explicit_oob_memacc_end());
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}
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};
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class VISIBILITY_HIDDEN BadSizeVLA : public BuiltinBug {
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public:
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BadSizeVLA(GRExprEngine* eng) :
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BuiltinBug(eng, "Bad variable-length array (VLA) size") {}
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void FlushReportsImpl(BugReporter& BR, GRExprEngine& Eng) {
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for (GRExprEngine::ErrorNodes::iterator
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I = Eng.ExplicitBadSizedVLA.begin(),
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E = Eng.ExplicitBadSizedVLA.end(); I!=E; ++I) {
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// Determine whether this was a 'zero-sized' VLA or a VLA with an
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// undefined size.
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GRExprEngine::NodeTy* N = *I;
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PostStmt PS = cast<PostStmt>(N->getLocation());
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DeclStmt *DS = cast<DeclStmt>(PS.getStmt());
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VarDecl* VD = cast<VarDecl>(*DS->decl_begin());
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QualType T = Eng.getContext().getCanonicalType(VD->getType());
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VariableArrayType* VT = cast<VariableArrayType>(T);
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Expr* SizeExpr = VT->getSizeExpr();
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std::string buf;
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llvm::raw_string_ostream os(buf);
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os << "The expression used to specify the number of elements in the "
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"variable-length array (VLA) '"
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<< VD->getNameAsString() << "' evaluates to ";
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if (Eng.getStateManager().GetSVal(N->getState(), SizeExpr).isUndef())
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os << "an undefined or garbage value.";
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else
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os << "0. VLAs with no elements have undefined behavior.";
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RangedBugReport *report = new RangedBugReport(*this, os.str().c_str(), N);
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report->addRange(SizeExpr->getSourceRange());
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BR.EmitReport(report);
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}
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}
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};
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//===----------------------------------------------------------------------===//
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// __attribute__(nonnull) checking
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class VISIBILITY_HIDDEN CheckAttrNonNull : public GRSimpleAPICheck {
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BugType *BT;
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BugReporter &BR;
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public:
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CheckAttrNonNull(BugReporter &br) : BT(0), BR(br) {}
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virtual bool Audit(ExplodedNode<GRState>* N, GRStateManager& VMgr) {
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CallExpr* CE = cast<CallExpr>(cast<PostStmt>(N->getLocation()).getStmt());
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const GRState* state = N->getState();
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SVal X = VMgr.GetSVal(state, CE->getCallee());
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if (!isa<loc::FuncVal>(X))
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return false;
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FunctionDecl* FD = dyn_cast<FunctionDecl>(cast<loc::FuncVal>(X).getDecl());
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const NonNullAttr* Att = FD->getAttr<NonNullAttr>();
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if (!Att)
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return false;
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// Iterate through the arguments of CE and check them for null.
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unsigned idx = 0;
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bool hasError = false;
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for (CallExpr::arg_iterator I=CE->arg_begin(), E=CE->arg_end(); I!=E;
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++I, ++idx) {
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if (!VMgr.isEqual(state, *I, 0) || !Att->isNonNull(idx))
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continue;
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// Lazily allocate the BugType object if it hasn't already been created.
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// Ownership is transferred to the BugReporter object once the BugReport
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// is passed to 'EmitWarning'.
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if (!BT) BT =
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new BugType("Argument with 'nonnull' attribute passed null", "API");
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RangedBugReport *R = new RangedBugReport(*BT,
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"Null pointer passed as an argument to a "
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"'nonnull' parameter", N);
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R->addRange((*I)->getSourceRange());
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BR.EmitReport(R);
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hasError = true;
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}
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return hasError;
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}
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};
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} // end anonymous namespace
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//===----------------------------------------------------------------------===//
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// Check registration.
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//===----------------------------------------------------------------------===//
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void GRExprEngine::RegisterInternalChecks() {
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// Register internal "built-in" BugTypes with the BugReporter. These BugTypes
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// are different than what probably many checks will do since they don't
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// create BugReports on-the-fly but instead wait until GRExprEngine finishes
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// analyzing a function. Generation of BugReport objects is done via a call
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// to 'FlushReports' from BugReporter.
|
|
BR.Register(new NullDeref(this));
|
|
BR.Register(new UndefinedDeref(this));
|
|
BR.Register(new UndefBranch(this));
|
|
BR.Register(new DivZero(this));
|
|
BR.Register(new UndefResult(this));
|
|
BR.Register(new BadCall(this));
|
|
BR.Register(new RetStack(this));
|
|
BR.Register(new RetUndef(this));
|
|
BR.Register(new BadArg(this));
|
|
BR.Register(new BadMsgExprArg(this));
|
|
BR.Register(new BadReceiver(this));
|
|
BR.Register(new OutOfBoundMemoryAccess(this));
|
|
BR.Register(new BadSizeVLA(this));
|
|
BR.Register(new NilReceiverStructRet(this));
|
|
BR.Register(new NilReceiverLargerThanVoidPtrRet(this));
|
|
|
|
// The following checks do not need to have their associated BugTypes
|
|
// explicitly registered with the BugReporter. If they issue any BugReports,
|
|
// their associated BugType will get registered with the BugReporter
|
|
// automatically. Note that the check itself is owned by the GRExprEngine
|
|
// object.
|
|
AddCheck(new CheckAttrNonNull(BR), Stmt::CallExprClass);
|
|
}
|