llvm-project/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp

467 lines
15 KiB
C++

//===-- StreamChecker.cpp -----------------------------------------*- C++ -*--//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines checkers that model and check stream handling functions.
//
//===----------------------------------------------------------------------===//
#include "ClangSACheckers.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/GRState.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/GRStateTrait.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
#include "llvm/ADT/ImmutableMap.h"
using namespace clang;
using namespace ento;
namespace {
struct StreamState {
enum Kind { Opened, Closed, OpenFailed, Escaped } K;
const Stmt *S;
StreamState(Kind k, const Stmt *s) : K(k), S(s) {}
bool isOpened() const { return K == Opened; }
bool isClosed() const { return K == Closed; }
//bool isOpenFailed() const { return K == OpenFailed; }
//bool isEscaped() const { return K == Escaped; }
bool operator==(const StreamState &X) const {
return K == X.K && S == X.S;
}
static StreamState getOpened(const Stmt *s) { return StreamState(Opened, s); }
static StreamState getClosed(const Stmt *s) { return StreamState(Closed, s); }
static StreamState getOpenFailed(const Stmt *s) {
return StreamState(OpenFailed, s);
}
static StreamState getEscaped(const Stmt *s) {
return StreamState(Escaped, s);
}
void Profile(llvm::FoldingSetNodeID &ID) const {
ID.AddInteger(K);
ID.AddPointer(S);
}
};
class StreamChecker : public Checker<eval::Call,
check::DeadSymbols,
check::EndPath,
check::PreStmt<ReturnStmt> > {
mutable IdentifierInfo *II_fopen, *II_tmpfile, *II_fclose, *II_fread,
*II_fwrite,
*II_fseek, *II_ftell, *II_rewind, *II_fgetpos, *II_fsetpos,
*II_clearerr, *II_feof, *II_ferror, *II_fileno;
mutable llvm::OwningPtr<BuiltinBug> BT_nullfp, BT_illegalwhence,
BT_doubleclose, BT_ResourceLeak;
public:
StreamChecker()
: II_fopen(0), II_tmpfile(0) ,II_fclose(0), II_fread(0), II_fwrite(0),
II_fseek(0), II_ftell(0), II_rewind(0), II_fgetpos(0), II_fsetpos(0),
II_clearerr(0), II_feof(0), II_ferror(0), II_fileno(0) {}
bool evalCall(const CallExpr *CE, CheckerContext &C) const;
void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
void checkEndPath(EndOfFunctionNodeBuilder &B, ExprEngine &Eng) const;
void checkPreStmt(const ReturnStmt *S, CheckerContext &C) const;
private:
void Fopen(CheckerContext &C, const CallExpr *CE) const;
void Tmpfile(CheckerContext &C, const CallExpr *CE) const;
void Fclose(CheckerContext &C, const CallExpr *CE) const;
void Fread(CheckerContext &C, const CallExpr *CE) const;
void Fwrite(CheckerContext &C, const CallExpr *CE) const;
void Fseek(CheckerContext &C, const CallExpr *CE) const;
void Ftell(CheckerContext &C, const CallExpr *CE) const;
void Rewind(CheckerContext &C, const CallExpr *CE) const;
void Fgetpos(CheckerContext &C, const CallExpr *CE) const;
void Fsetpos(CheckerContext &C, const CallExpr *CE) const;
void Clearerr(CheckerContext &C, const CallExpr *CE) const;
void Feof(CheckerContext &C, const CallExpr *CE) const;
void Ferror(CheckerContext &C, const CallExpr *CE) const;
void Fileno(CheckerContext &C, const CallExpr *CE) const;
void OpenFileAux(CheckerContext &C, const CallExpr *CE) const;
const GRState *CheckNullStream(SVal SV, const GRState *state,
CheckerContext &C) const;
const GRState *CheckDoubleClose(const CallExpr *CE, const GRState *state,
CheckerContext &C) const;
};
} // end anonymous namespace
namespace clang {
namespace ento {
template <>
struct GRStateTrait<StreamState>
: public GRStatePartialTrait<llvm::ImmutableMap<SymbolRef, StreamState> > {
static void *GDMIndex() { static int x; return &x; }
};
}
}
bool StreamChecker::evalCall(const CallExpr *CE, CheckerContext &C) const {
const GRState *state = C.getState();
const Expr *Callee = CE->getCallee();
SVal L = state->getSVal(Callee);
const FunctionDecl *FD = L.getAsFunctionDecl();
if (!FD)
return false;
ASTContext &Ctx = C.getASTContext();
if (!II_fopen)
II_fopen = &Ctx.Idents.get("fopen");
if (!II_tmpfile)
II_tmpfile = &Ctx.Idents.get("tmpfile");
if (!II_fclose)
II_fclose = &Ctx.Idents.get("fclose");
if (!II_fread)
II_fread = &Ctx.Idents.get("fread");
if (!II_fwrite)
II_fwrite = &Ctx.Idents.get("fwrite");
if (!II_fseek)
II_fseek = &Ctx.Idents.get("fseek");
if (!II_ftell)
II_ftell = &Ctx.Idents.get("ftell");
if (!II_rewind)
II_rewind = &Ctx.Idents.get("rewind");
if (!II_fgetpos)
II_fgetpos = &Ctx.Idents.get("fgetpos");
if (!II_fsetpos)
II_fsetpos = &Ctx.Idents.get("fsetpos");
if (!II_clearerr)
II_clearerr = &Ctx.Idents.get("clearerr");
if (!II_feof)
II_feof = &Ctx.Idents.get("feof");
if (!II_ferror)
II_ferror = &Ctx.Idents.get("ferror");
if (!II_fileno)
II_fileno = &Ctx.Idents.get("fileno");
if (FD->getIdentifier() == II_fopen) {
Fopen(C, CE);
return true;
}
if (FD->getIdentifier() == II_tmpfile) {
Tmpfile(C, CE);
return true;
}
if (FD->getIdentifier() == II_fclose) {
Fclose(C, CE);
return true;
}
if (FD->getIdentifier() == II_fread) {
Fread(C, CE);
return true;
}
if (FD->getIdentifier() == II_fwrite) {
Fwrite(C, CE);
return true;
}
if (FD->getIdentifier() == II_fseek) {
Fseek(C, CE);
return true;
}
if (FD->getIdentifier() == II_ftell) {
Ftell(C, CE);
return true;
}
if (FD->getIdentifier() == II_rewind) {
Rewind(C, CE);
return true;
}
if (FD->getIdentifier() == II_fgetpos) {
Fgetpos(C, CE);
return true;
}
if (FD->getIdentifier() == II_fsetpos) {
Fsetpos(C, CE);
return true;
}
if (FD->getIdentifier() == II_clearerr) {
Clearerr(C, CE);
return true;
}
if (FD->getIdentifier() == II_feof) {
Feof(C, CE);
return true;
}
if (FD->getIdentifier() == II_ferror) {
Ferror(C, CE);
return true;
}
if (FD->getIdentifier() == II_fileno) {
Fileno(C, CE);
return true;
}
return false;
}
void StreamChecker::Fopen(CheckerContext &C, const CallExpr *CE) const {
OpenFileAux(C, CE);
}
void StreamChecker::Tmpfile(CheckerContext &C, const CallExpr *CE) const {
OpenFileAux(C, CE);
}
void StreamChecker::OpenFileAux(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
unsigned Count = C.getNodeBuilder().getCurrentBlockCount();
SValBuilder &svalBuilder = C.getSValBuilder();
DefinedSVal RetVal =
cast<DefinedSVal>(svalBuilder.getConjuredSymbolVal(0, CE, Count));
state = state->BindExpr(CE, RetVal);
ConstraintManager &CM = C.getConstraintManager();
// Bifurcate the state into two: one with a valid FILE* pointer, the other
// with a NULL.
const GRState *stateNotNull, *stateNull;
llvm::tie(stateNotNull, stateNull) = CM.assumeDual(state, RetVal);
if (SymbolRef Sym = RetVal.getAsSymbol()) {
// if RetVal is not NULL, set the symbol's state to Opened.
stateNotNull =
stateNotNull->set<StreamState>(Sym,StreamState::getOpened(CE));
stateNull =
stateNull->set<StreamState>(Sym, StreamState::getOpenFailed(CE));
C.addTransition(stateNotNull);
C.addTransition(stateNull);
}
}
void StreamChecker::Fclose(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = CheckDoubleClose(CE, C.getState(), C);
if (state)
C.addTransition(state);
}
void StreamChecker::Fread(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(3)), state, C))
return;
}
void StreamChecker::Fwrite(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(3)), state, C))
return;
}
void StreamChecker::Fseek(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!(state = CheckNullStream(state->getSVal(CE->getArg(0)), state, C)))
return;
// Check the legality of the 'whence' argument of 'fseek'.
SVal Whence = state->getSVal(CE->getArg(2));
const nonloc::ConcreteInt *CI = dyn_cast<nonloc::ConcreteInt>(&Whence);
if (!CI)
return;
int64_t x = CI->getValue().getSExtValue();
if (x >= 0 && x <= 2)
return;
if (ExplodedNode *N = C.generateNode(state)) {
if (!BT_illegalwhence)
BT_illegalwhence.reset(new BuiltinBug("Illegal whence argument",
"The whence argument to fseek() should be "
"SEEK_SET, SEEK_END, or SEEK_CUR."));
BugReport *R = new BugReport(*BT_illegalwhence,
BT_illegalwhence->getDescription(), N);
C.EmitReport(R);
}
}
void StreamChecker::Ftell(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::Rewind(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::Fgetpos(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::Fsetpos(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::Clearerr(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::Feof(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::Ferror(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::Fileno(CheckerContext &C, const CallExpr *CE) const {
const GRState *state = C.getState();
if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
const GRState *StreamChecker::CheckNullStream(SVal SV, const GRState *state,
CheckerContext &C) const {
const DefinedSVal *DV = dyn_cast<DefinedSVal>(&SV);
if (!DV)
return 0;
ConstraintManager &CM = C.getConstraintManager();
const GRState *stateNotNull, *stateNull;
llvm::tie(stateNotNull, stateNull) = CM.assumeDual(state, *DV);
if (!stateNotNull && stateNull) {
if (ExplodedNode *N = C.generateSink(stateNull)) {
if (!BT_nullfp)
BT_nullfp.reset(new BuiltinBug("NULL stream pointer",
"Stream pointer might be NULL."));
BugReport *R =new BugReport(*BT_nullfp, BT_nullfp->getDescription(), N);
C.EmitReport(R);
}
return 0;
}
return stateNotNull;
}
const GRState *StreamChecker::CheckDoubleClose(const CallExpr *CE,
const GRState *state,
CheckerContext &C) const {
SymbolRef Sym = state->getSVal(CE->getArg(0)).getAsSymbol();
if (!Sym)
return state;
const StreamState *SS = state->get<StreamState>(Sym);
// If the file stream is not tracked, return.
if (!SS)
return state;
// Check: Double close a File Descriptor could cause undefined behaviour.
// Conforming to man-pages
if (SS->isClosed()) {
ExplodedNode *N = C.generateSink();
if (N) {
if (!BT_doubleclose)
BT_doubleclose.reset(new BuiltinBug("Double fclose",
"Try to close a file Descriptor already"
" closed. Cause undefined behaviour."));
BugReport *R = new BugReport(*BT_doubleclose,
BT_doubleclose->getDescription(), N);
C.EmitReport(R);
}
return NULL;
}
// Close the File Descriptor.
return state->set<StreamState>(Sym, StreamState::getClosed(CE));
}
void StreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
CheckerContext &C) const {
for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
E = SymReaper.dead_end(); I != E; ++I) {
SymbolRef Sym = *I;
const GRState *state = C.getState();
const StreamState *SS = state->get<StreamState>(Sym);
if (!SS)
return;
if (SS->isOpened()) {
ExplodedNode *N = C.generateSink();
if (N) {
if (!BT_ResourceLeak)
BT_ResourceLeak.reset(new BuiltinBug("Resource Leak",
"Opened File never closed. Potential Resource leak."));
BugReport *R = new BugReport(*BT_ResourceLeak,
BT_ResourceLeak->getDescription(), N);
C.EmitReport(R);
}
}
}
}
void StreamChecker::checkEndPath(EndOfFunctionNodeBuilder &B,
ExprEngine &Eng) const {
const GRState *state = B.getState();
typedef llvm::ImmutableMap<SymbolRef, StreamState> SymMap;
SymMap M = state->get<StreamState>();
for (SymMap::iterator I = M.begin(), E = M.end(); I != E; ++I) {
StreamState SS = I->second;
if (SS.isOpened()) {
ExplodedNode *N = B.generateNode(state);
if (N) {
if (!BT_ResourceLeak)
BT_ResourceLeak.reset(new BuiltinBug("Resource Leak",
"Opened File never closed. Potential Resource leak."));
BugReport *R = new BugReport(*BT_ResourceLeak,
BT_ResourceLeak->getDescription(), N);
Eng.getBugReporter().EmitReport(R);
}
}
}
}
void StreamChecker::checkPreStmt(const ReturnStmt *S, CheckerContext &C) const {
const Expr *RetE = S->getRetValue();
if (!RetE)
return;
const GRState *state = C.getState();
SymbolRef Sym = state->getSVal(RetE).getAsSymbol();
if (!Sym)
return;
const StreamState *SS = state->get<StreamState>(Sym);
if(!SS)
return;
if (SS->isOpened())
state = state->set<StreamState>(Sym, StreamState::getEscaped(S));
C.addTransition(state);
}
void ento::registerStreamChecker(CheckerManager &mgr) {
mgr.registerChecker<StreamChecker>();
}