Untitled diff
140 removals
271 lines
115 additions
255 lines
//===-- SimpleStreamChecker.cpp -----------------------------------------*- C++ -*--//
//===-- SimpleStreamChecker.cpp -----------------------------------------*- C++ -*--//
//
//
// The LLVM Compiler Infrastructure
// The LLVM Compiler Infrastructure
//
//
// This file is distributed under the University of Illinois Open Source
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// License. See LICENSE.TXT for details.
//
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
//
//
// Defines a checker for proper use of fopen/fclose APIs.
// Defines a checker for proper use of fopen/fclose APIs.
// - If a file has been closed with fclose, it should not be accessed again.
// - If a file has been closed with fclose, it should not be accessed again.
// Accessing a closed file results in undefined behavior.
// Accessing a closed file results in undefined behavior.
// - If a file was opened with fopen, it must be closed with fclose before
// - If a file was opened with fopen, it must be closed with fclose before
// the execution ends. Failing to do so results in a resource leak.
// the execution ends. Failing to do so results in a resource leak.
//
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
#include "ClangSACheckers.h"
#include "ClangSACheckers.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
using namespace clang;
using namespace clang;
using namespace ento;
using namespace ento;
namespace {
namespace {
enum SimpleStreamState { Closed, Opened };
SmartStateTrait SimpleStreamTrait;
typedef SmallVector<SymbolRef, 2> SymbolVector;
typedef SmallVector<SymbolRef, 2> SymbolVector;
struct StreamState {
class SimpleStreamModel
private:
: public Checker<check::ASTDecl<TranslationUnitDecl>, check::PostCall,
enum Kind { Opened, Closed } K;
check::PointerEscape> {
StreamState(Kind InK) : K(InK) { }
CallDescription OpenFn, CloseFn;
bool guaranteedNotToCloseFile(const CallEvent &Call) const;
public:
public:
bool isOpened() const { return K == Opened; }
SimpleStreamModel() : OpenFn("fopen"), CloseFn("fclose") {}
bool isClosed() const { return K == Closed; }
static StreamState getOpened() { return StreamState(Opened); }
void checkASTDecl(const TranslationUnitDecl *D, AnalysisManager &AMgr,
static StreamState getClosed() { return StreamState(Closed); }
BugReporter &BR) const;
void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
ProgramStateRef checkPointerEscape(ProgramStateRef State,
const InvalidatedSymbols &Escaped,
const CallEvent *Call,
PointerEscapeKind Kind) const;
};
} // end of anonymous namespace
bool operator==(const StreamState &X) const {
bool SimpleStreamModel::guaranteedNotToCloseFile(
return K == X.K;
const CallEvent &Call) const {
Text moved from lines 230-239
// If it's not in a system header, assume it might close a file.
if (!Call.isInSystemHeader())
return false;
// Handle cases where we know a buffer's /address/ can escape.
if (Call.argumentsMayEscape())
return false;
// Note, even though fclose closes the file, we do not list it here
// since the checker is modeling the call.
Text moved with changes from lines 241-244 (91.3% similarity)
return true;
}
void SimpleStreamModel::checkASTDecl(const TranslationUnitDecl *D,
AnalysisManager &AMgr,
BugReporter &BR) const {
// Once the AST context is available, we can express the fact that our trait
// has type 'int'.
// FIXME: This is ugly. Maybe make a separate callback, or delay registering
// checkers until AST is constructed?
SimpleStreamTrait.initialize("SimpleStream", AMgr.getASTContext().IntTy);
}
Text moved with changes from lines 117-122 (98.1% similarity)
void SimpleStreamModel::checkPostCall(const CallEvent &Call,
CheckerContext &C) const {
if (!Call.isGlobalCFunction())
return;
if (Call.isCalled(OpenFn)) {
// Get the symbolic value corresponding to the file handle.
SymbolRef FileDesc = Call.getReturnValue().getAsSymbol();
if (!FileDesc)
return;
// Generate the next transition (an edge in the exploded graph).
ProgramStateRef State = C.getState();
State = State->bindLoc(SimpleStreamTrait, FileDesc, Opened);
C.addTransition(State);
} else if (Call.isCalled(CloseFn)) {
// Get the symbolic value corresponding to the file handle.
SymbolRef FileDesc = Call.getArgSVal(0).getAsSymbol();
if (!FileDesc)
return;
// Generate the next transition, in which the stream is closed.
ProgramStateRef State = C.getState();
State = State->bindLoc(SimpleStreamTrait, FileDesc, Closed);
C.addTransition(State);
}
}
void Profile(llvm::FoldingSetNodeID &ID) const {
}
ID.AddInteger(K);
ProgramStateRef SimpleStreamModel::checkPointerEscape(
ProgramStateRef State, const InvalidatedSymbols &Escaped,
const CallEvent *Call, PointerEscapeKind Kind) const {
// If we know that the call cannot close a file, there is nothing to do.
if (Kind == PSK_DirectEscapeOnCall && guaranteedNotToCloseFile(*Call))
return State;
for (auto I = Escaped.begin(), E = Escaped.end(); I != E; ++I) {
Text moved from lines 259-262
SymbolRef Sym = *I;
// The symbol escaped. Optimistically, assume that the corresponding file
// handle will be closed somewhere else.
// FIXME: We're doing double lookup here, and we could have probably just
// deleted the binding, because our checker doesn't discriminate between
// different kind of unknowns.
if (State->hasAnyBinding(SimpleStreamTrait, Sym))
State = State->bindLoc(SimpleStreamTrait, Sym, UnknownVal());
}
}
};
return State;
}
class SimpleStreamChecker : public Checker<check::PostCall,
namespace {
check::PreCall,
class SimpleStreamChecker
check::DeadSymbols,
: public Checker<check::PreCall, check::DeadSymbols> {
check::PointerEscape> {
CallDescription CloseFn;
CallDescription OpenFn, CloseFn;
std::unique_ptr<BugType> DoubleCloseBugType;
std::unique_ptr<BugType> DoubleCloseBugType;
std::unique_ptr<BugType> LeakBugType;
std::unique_ptr<BugType> LeakBugType;
void reportDoubleClose(SymbolRef FileDescSym,
void reportDoubleClose(SymbolRef FileDescSym,
const CallEvent &Call,
const CallEvent &Call,
CheckerContext &C) const;
CheckerContext &C) const;
void reportLeaks(ArrayRef<SymbolRef> LeakedStreams, CheckerContext &C,
void reportLeaks(ArrayRef<SymbolRef> LeakedStreams, CheckerContext &C,
ExplodedNode *ErrNode) const;
ExplodedNode *ErrNode) const;
bool guaranteedNotToCloseFile(const CallEvent &Call) const;
public:
public:
SimpleStreamChecker();
SimpleStreamChecker();
/// Process fopen.
void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
/// Process fclose.
/// Process fclose.
void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
/// Detect leaks.
void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
/// Stop tracking addresses which escape.
ProgramStateRef checkPointerEscape(ProgramStateRef State,
const InvalidatedSymbols &Escaped,
const CallEvent *Call,
PointerEscapeKind Kind) const;
};
} // end anonymous namespace
/// The state of the checker is a map from tracked stream symbols to their
/// state. Let's store it in the ProgramState.
REGISTER_MAP_WITH_PROGRAMSTATE(StreamMap, SymbolRef, StreamState)
namespace {
class StopTrackingCallback final : public SymbolVisitor {
ProgramStateRef state;
public:
StopTrackingCallback(ProgramStateRef st) : state(st) {}
ProgramStateRef getState() const { return state; }
bool VisitSymbol(SymbolRef sym) override {
state = state->remove<StreamMap>(sym);
return true;
}
};
};
} // end anonymous namespace
} // end anonymous namespace
SimpleStreamChecker::SimpleStreamChecker()
SimpleStreamChecker::SimpleStreamChecker() : CloseFn("fclose", 1) {
: OpenFn("fopen"), CloseFn("fclose", 1) {
// Initialize the bug types.
// Initialize the bug types.
DoubleCloseBugType.reset(
DoubleCloseBugType.reset(
new BugType(this, "Double fclose", "Unix Stream API Error"));
new BugType(this, "Double fclose", "Unix Stream API Error"));
LeakBugType.reset(
LeakBugType.reset(
new BugType(this, "Resource Leak", "Unix Stream API Error"));
new BugType(this, "Resource Leak", "Unix Stream API Error"));
// Sinks are higher importance bugs as well as calls to assert() or exit(0).
// Sinks are higher importance bugs as well as calls to assert() or exit(0).
LeakBugType->setSuppressOnSink(true);
LeakBugType->setSuppressOnSink(true);
}
}
Text moved with changes to lines 76-81 (98.1% similarity)
void SimpleStreamChecker::checkPostCall(const CallEvent &Call,
CheckerContext &C) const {
if (!Call.isGlobalCFunction())
return;
if (!Call.isCalled(OpenFn))
return;
// Get the symbolic value corresponding to the file handle.
SymbolRef FileDesc = Call.getReturnValue().getAsSymbol();
if (!FileDesc)
return;
// Generate the next transition (an edge in the exploded graph).
ProgramStateRef State = C.getState();
State = State->set<StreamMap>(FileDesc, StreamState::getOpened());
C.addTransition(State);
}
void SimpleStreamChecker::checkPreCall(const CallEvent &Call,
void SimpleStreamChecker::checkPreCall(const CallEvent &Call,
CheckerContext &C) const {
CheckerContext &C) const {
if (!Call.isGlobalCFunction())
if (!Call.isGlobalCFunction())
return;
return;
if (!Call.isCalled(CloseFn))
if (!Call.isCalled(CloseFn))
return;
return;
// Get the symbolic value corresponding to the file handle.
// Get the symbolic value corresponding to the file handle.
SymbolRef FileDesc = Call.getArgSVal(0).getAsSymbol();
SymbolRef FileDesc = Call.getArgSVal(0).getAsSymbol();
if (!FileDesc)
if (!FileDesc)
return;
return;
// Check if the stream has already been closed.
// Check if the stream has already been closed.
ProgramStateRef State = C.getState();
ProgramStateRef State = C.getState();
const StreamState *SS = State->get<StreamMap>(FileDesc);
SVal Val = State->getSVal(SimpleStreamTrait, FileDesc);
if (SS && SS->isClosed()) {
if (Val.isConstant(Closed)) {
reportDoubleClose(FileDesc, Call, C);
reportDoubleClose(FileDesc, Call, C);
return;
return;
}
}
// Generate the next transition, in which the stream is closed.
State = State->set<StreamMap>(FileDesc, StreamState::getClosed());
C.addTransition(State);
}
}
static bool isLeaked(SymbolRef Sym, const StreamState &SS,
static bool isLeaked(SymbolRef Sym, ProgramStateRef State) {
bool IsSymDead, ProgramStateRef State) {
// If a symbol is NULL, assume that fopen failed on this path.
if (IsSymDead && SS.isOpened()) {
// A symbol should only be considered leaked if it is non-null.
// If a symbol is NULL, assume that fopen failed on this path.
ConstraintManager &CMgr = State->getConstraintManager();
// A symbol should only be considered leaked if it is non-null.
ConditionTruthVal OpenFailed = CMgr.isNull(State, Sym);
ConstraintManager &CMgr = State->getConstraintManager();
return !OpenFailed.isConstrainedTrue();
ConditionTruthVal OpenFailed = CMgr.isNull(State, Sym);
return !OpenFailed.isConstrainedTrue();
}
return false;
}
}
void SimpleStreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
void SimpleStreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
CheckerContext &C) const {
CheckerContext &C) const {
ProgramStateRef State = C.getState();
ProgramStateRef State = C.getState();
SymbolVector LeakedStreams;
SymbolVector LeakedStreams;
StreamMapTy TrackedStreams = State->get<StreamMap>();
// FIXME: Iterate through trait, not through dead symbols (might be faster)?
for (StreamMapTy::iterator I = TrackedStreams.begin(),
for (auto I = SymReaper.dead_begin(), E = SymReaper.dead_end(); I != E; ++I) {
E = TrackedStreams.end(); I != E; ++I) {
SymbolRef FileDesc = *I;
SymbolRef Sym = I->first;
SVal Val = State->getSVal(SimpleStreamTrait, FileDesc);
bool IsSymDead = SymReaper.isDead(Sym);
if (!Val.isConstant(Opened))
continue;
// Collect leaked symbols.
// Collect leaked symbols.
if (isLeaked(Sym, I->second, IsSymDead, State))
if (isLeaked(FileDesc, State))
LeakedStreams.push_back(Sym);
LeakedStreams.push_back(FileDesc);
// Remove the dead symbol from the streams map.
if (IsSymDead)
State = State->remove<StreamMap>(Sym);
}
}
if (LeakedStreams.empty())
return;
ExplodedNode *N = C.generateNonFatalErrorNode(State);
ExplodedNode *N = C.generateNonFatalErrorNode(State);
if (!N)
if (!N)
return;
return;
reportLeaks(LeakedStreams, C, N);
reportLeaks(LeakedStreams, C, N);
}
}
void SimpleStreamChecker::reportDoubleClose(SymbolRef FileDescSym,
void SimpleStreamChecker::reportDoubleClose(SymbolRef FileDescSym,
const CallEvent &Call,
const CallEvent &Call,
CheckerContext &C) const {
CheckerContext &C) const {
// We reached a bug, stop exploring the path here by generating a sink.
// We reached a bug, stop exploring the path here by generating a sink.
ExplodedNode *ErrNode = C.generateErrorNode();
ExplodedNode *ErrNode = C.generateErrorNode();
// If we've already reached this node on another path, return.
// If we've already reached this node on another path, return.
if (!ErrNode)
if (!ErrNode)
return;
return;
// Generate the report.
// Generate the report.
auto R = llvm::make_unique<BugReport>(*DoubleCloseBugType,
auto R = llvm::make_unique<BugReport>(*DoubleCloseBugType,
"Closing a previously closed file stream", ErrNode);
"Closing a previously closed file stream", ErrNode);
R->addRange(Call.getSourceRange());
R->addRange(Call.getSourceRange());
R->markInteresting(FileDescSym);
R->markInteresting(FileDescSym);
C.emitReport(std::move(R));
C.emitReport(std::move(R));
}
}
void SimpleStreamChecker::reportLeaks(ArrayRef<SymbolRef> LeakedStreams,
void SimpleStreamChecker::reportLeaks(ArrayRef<SymbolRef> LeakedStreams,
CheckerContext &C,
CheckerContext &C,
ExplodedNode *ErrNode) const {
ExplodedNode *ErrNode) const {
// Attach bug reports to the leak node.
// Attach bug reports to the leak node.
// TODO: Identify the leaked file descriptor.
// TODO: Identify the leaked file descriptor.
for (SymbolRef LeakedStream : LeakedStreams) {
for (SymbolRef LeakedStream : LeakedStreams) {
auto R = llvm::make_unique<BugReport>(*LeakBugType,
auto R = llvm::make_unique<BugReport>(*LeakBugType,
"Opened file is never closed; potential resource leak", ErrNode);
"Opened file is never closed; potential resource leak", ErrNode);
R->markInteresting(LeakedStream);
R->markInteresting(LeakedStream);
C.emitReport(std::move(R));
C.emitReport(std::move(R));
}
}
}
}
bool SimpleStreamChecker::guaranteedNotToCloseFile(const CallEvent &Call) const{
void ento::registerSimpleStreamCheckerV2(CheckerManager &mgr) {
Text moved to lines 53-62
// If it's not in a system header, assume it might close a file.
mgr.registerChecker<SimpleStreamModel>();
if (!Call.isInSystemHeader())
return false;
// Handle cases where we know a buffer's /address/ can escape.
if (Call.argumentsMayEscape())
return false;
// Note, even though fclose closes the file, we do not list it here
// since the checker is modeling the call.
Text moved with changes to lines 63-66 (91.3% similarity)
return true;
}
// If the pointer we are tracking escaped, do not track the symbol as
// we cannot reason about it anymore.
ProgramStateRef
SimpleStreamChecker::checkPointerEscape(ProgramStateRef State,
const InvalidatedSymbols &Escaped,
const CallEvent *Call,
PointerEscapeKind Kind) const {
// If we know that the call cannot close a file, there is nothing to do.
if (Kind == PSK_DirectEscapeOnCall && guaranteedNotToCloseFile(*Call)) {
return State;
}
for (InvalidatedSymbols::const_iterator I = Escaped.begin(),
E = Escaped.end();
I != E; ++I) {
Text moved to lines 115-118
SymbolRef Sym = *I;
// The symbol escaped. Optimistically, assume that the corresponding file
// handle will be closed somewhere else.
State = State->remove<StreamMap>(Sym);
}
return State;
}
void ento::registerSimpleStreamChecker(CheckerManager &mgr) {
mgr.registerChecker<SimpleStreamChecker>();
mgr.registerChecker<SimpleStreamChecker>();
}
}