| //===-- 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 "ExprEngineExperimentalChecks.h" |
| #include "clang/GR/BugReporter/BugType.h" |
| #include "clang/GR/PathSensitive/CheckerVisitor.h" |
| #include "clang/GR/PathSensitive/GRState.h" |
| #include "clang/GR/PathSensitive/GRStateTrait.h" |
| #include "clang/GR/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 CheckerVisitor<StreamChecker> { |
| 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; |
| 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), |
| BT_nullfp(0), BT_illegalwhence(0), BT_doubleclose(0), |
| BT_ResourceLeak(0) {} |
| |
| static void *getTag() { |
| static int x; |
| return &x; |
| } |
| |
| virtual bool evalCallExpr(CheckerContext &C, const CallExpr *CE); |
| void evalDeadSymbols(CheckerContext &C, SymbolReaper &SymReaper); |
| void evalEndPath(EndPathNodeBuilder &B, void *tag, ExprEngine &Eng); |
| void PreVisitReturnStmt(CheckerContext &C, const ReturnStmt *S); |
| |
| private: |
| void Fopen(CheckerContext &C, const CallExpr *CE); |
| void Tmpfile(CheckerContext &C, const CallExpr *CE); |
| void Fclose(CheckerContext &C, const CallExpr *CE); |
| void Fread(CheckerContext &C, const CallExpr *CE); |
| void Fwrite(CheckerContext &C, const CallExpr *CE); |
| void Fseek(CheckerContext &C, const CallExpr *CE); |
| void Ftell(CheckerContext &C, const CallExpr *CE); |
| void Rewind(CheckerContext &C, const CallExpr *CE); |
| void Fgetpos(CheckerContext &C, const CallExpr *CE); |
| void Fsetpos(CheckerContext &C, const CallExpr *CE); |
| void Clearerr(CheckerContext &C, const CallExpr *CE); |
| void Feof(CheckerContext &C, const CallExpr *CE); |
| void Ferror(CheckerContext &C, const CallExpr *CE); |
| void Fileno(CheckerContext &C, const CallExpr *CE); |
| |
| void OpenFileAux(CheckerContext &C, const CallExpr *CE); |
| |
| const GRState *CheckNullStream(SVal SV, const GRState *state, |
| CheckerContext &C); |
| const GRState *CheckDoubleClose(const CallExpr *CE, const GRState *state, |
| CheckerContext &C); |
| }; |
| |
| } // end anonymous namespace |
| |
| namespace clang { |
| namespace ento { |
| template <> |
| struct GRStateTrait<StreamState> |
| : public GRStatePartialTrait<llvm::ImmutableMap<SymbolRef, StreamState> > { |
| static void *GDMIndex() { return StreamChecker::getTag(); } |
| }; |
| } |
| } |
| |
| void ento::RegisterStreamChecker(ExprEngine &Eng) { |
| Eng.registerCheck(new StreamChecker()); |
| } |
| |
| bool StreamChecker::evalCallExpr(CheckerContext &C, const CallExpr *CE) { |
| 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) { |
| OpenFileAux(C, CE); |
| } |
| |
| void StreamChecker::Tmpfile(CheckerContext &C, const CallExpr *CE) { |
| OpenFileAux(C, CE); |
| } |
| |
| void StreamChecker::OpenFileAux(CheckerContext &C, const CallExpr *CE) { |
| 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 GRState *state = CheckDoubleClose(CE, C.getState(), C); |
| if (state) |
| C.addTransition(state); |
| } |
| |
| void StreamChecker::Fread(CheckerContext &C, const CallExpr *CE) { |
| const GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(3)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Fwrite(CheckerContext &C, const CallExpr *CE) { |
| const GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(3)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Fseek(CheckerContext &C, const CallExpr *CE) { |
| 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 = 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 GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Rewind(CheckerContext &C, const CallExpr *CE) { |
| const GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Fgetpos(CheckerContext &C, const CallExpr *CE) { |
| const GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Fsetpos(CheckerContext &C, const CallExpr *CE) { |
| const GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Clearerr(CheckerContext &C, const CallExpr *CE) { |
| const GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Feof(CheckerContext &C, const CallExpr *CE) { |
| const GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Ferror(CheckerContext &C, const CallExpr *CE) { |
| const GRState *state = C.getState(); |
| if (!CheckNullStream(state->getSVal(CE->getArg(0)), state, C)) |
| return; |
| } |
| |
| void StreamChecker::Fileno(CheckerContext &C, const CallExpr *CE) { |
| 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 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 = 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) { |
| 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 = 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::evalDeadSymbols(CheckerContext &C,SymbolReaper &SymReaper) { |
| 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 = 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::evalEndPath(EndPathNodeBuilder &B, void *tag, |
| ExprEngine &Eng) { |
| SaveAndRestore<bool> OldHasGen(B.HasGeneratedNode); |
| 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, tag, B.getPredecessor()); |
| if (N) { |
| if (!BT_ResourceLeak) |
| BT_ResourceLeak = 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::PreVisitReturnStmt(CheckerContext &C, const ReturnStmt *S) { |
| 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); |
| } |