diff options
| -rw-r--r-- | clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp | 69 | ||||
| -rw-r--r-- | clang/test/Analysis/stream-error.c | 25 | ||||
| -rw-r--r-- | clang/test/Analysis/stream.c | 6 |
3 files changed, 100 insertions, 0 deletions
diff --git a/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp index 95c7503..8492373 100644 --- a/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp +++ b/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp @@ -266,6 +266,9 @@ private: {{{"fprintf"}}, {std::bind(&StreamChecker::preReadWrite, _1, _2, _3, _4, false), std::bind(&StreamChecker::evalFprintf, _1, _2, _3, _4), 0}}, + {{{"fscanf"}}, + {std::bind(&StreamChecker::preReadWrite, _1, _2, _3, _4, true), + std::bind(&StreamChecker::evalFscanf, _1, _2, _3, _4), 0}}, {{{"ungetc"}, 2}, {std::bind(&StreamChecker::preReadWrite, _1, _2, _3, _4, false), std::bind(&StreamChecker::evalUngetc, _1, _2, _3, _4), 1}}, @@ -345,6 +348,9 @@ private: void evalFprintf(const FnDescription *Desc, const CallEvent &Call, CheckerContext &C) const; + void evalFscanf(const FnDescription *Desc, const CallEvent &Call, + CheckerContext &C) const; + void evalUngetc(const FnDescription *Desc, const CallEvent &Call, CheckerContext &C) const; @@ -975,6 +981,69 @@ void StreamChecker::evalFprintf(const FnDescription *Desc, C.addTransition(StateFailed); } +void StreamChecker::evalFscanf(const FnDescription *Desc, const CallEvent &Call, + CheckerContext &C) const { + ProgramStateRef State = C.getState(); + if (Call.getNumArgs() < 2) + return; + SymbolRef StreamSym = getStreamArg(Desc, Call).getAsSymbol(); + if (!StreamSym) + return; + + const CallExpr *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr()); + if (!CE) + return; + + const StreamState *OldSS = State->get<StreamMap>(StreamSym); + if (!OldSS) + return; + + assertStreamStateOpened(OldSS); + + SValBuilder &SVB = C.getSValBuilder(); + ASTContext &ACtx = C.getASTContext(); + + // Add the success state. + // In this context "success" means there is not an EOF or other read error + // before any item is matched in 'fscanf'. But there may be match failure, + // therefore return value can be 0 or greater. + // It is not specified what happens if some items (not all) are matched and + // then EOF or read error happens. Now this case is handled like a "success" + // case, and no error flags are set on the stream. This is probably not + // accurate, and the POSIX documentation does not tell more. + if (OldSS->ErrorState != ErrorFEof) { + NonLoc RetVal = makeRetVal(C, CE).castAs<NonLoc>(); + ProgramStateRef StateNotFailed = + State->BindExpr(CE, C.getLocationContext(), RetVal); + auto RetGeZero = + SVB.evalBinOp(StateNotFailed, BO_GE, RetVal, + SVB.makeZeroVal(ACtx.IntTy), SVB.getConditionType()) + .getAs<DefinedOrUnknownSVal>(); + if (!RetGeZero) + return; + StateNotFailed = StateNotFailed->assume(*RetGeZero, true); + + C.addTransition(StateNotFailed); + } + + // Add transition for the failed state. + // Error occurs if nothing is matched yet and reading the input fails. + // Error can be EOF, or other error. At "other error" FERROR or 'errno' can + // be set but it is not further specified if all are required to be set. + // Documentation does not mention, but file position will be set to + // indeterminate similarly as at 'fread'. + ProgramStateRef StateFailed = bindInt(*EofVal, State, C, CE); + StreamErrorState NewES = (OldSS->ErrorState == ErrorFEof) + ? ErrorFEof + : ErrorNone | ErrorFEof | ErrorFError; + StreamState NewSS = StreamState::getOpened(Desc, NewES, !NewES.isFEof()); + StateFailed = StateFailed->set<StreamMap>(StreamSym, NewSS); + if (OldSS->ErrorState != ErrorFEof) + C.addTransition(StateFailed, constructSetEofNoteTag(C, StreamSym)); + else + C.addTransition(StateFailed); +} + void StreamChecker::evalUngetc(const FnDescription *Desc, const CallEvent &Call, CheckerContext &C) const { ProgramStateRef State = C.getState(); diff --git a/clang/test/Analysis/stream-error.c b/clang/test/Analysis/stream-error.c index 0f7fddd..2cf46e1 100644 --- a/clang/test/Analysis/stream-error.c +++ b/clang/test/Analysis/stream-error.c @@ -208,6 +208,31 @@ void error_fprintf(void) { fprintf(F, "ccc"); // expected-warning {{Stream might be already closed}} } +void error_fscanf(int *A) { + FILE *F = tmpfile(); + if (!F) + return; + int Ret = fscanf(F, "a%ib", A); + if (Ret >= 0) { + clang_analyzer_eval(feof(F) || ferror(F)); // expected-warning {{FALSE}} + fscanf(F, "bbb"); // no-warning + } else { + if (ferror(F)) { + clang_analyzer_warnIfReached(); // expected-warning {{REACHABLE}} + fscanf(F, "bbb"); // expected-warning {{might be 'indeterminate'}} + } else if (feof(F)) { + clang_analyzer_warnIfReached(); // expected-warning {{REACHABLE}} + fscanf(F, "bbb"); // expected-warning {{is in EOF state}} + clang_analyzer_eval(feof(F)); // expected-warning {{TRUE}} + } else { + clang_analyzer_warnIfReached(); // expected-warning {{REACHABLE}} + fscanf(F, "bbb"); // expected-warning {{might be 'indeterminate'}} + } + } + fclose(F); + fscanf(F, "ccc"); // expected-warning {{Stream might be already closed}} +} + void error_ungetc() { FILE *F = tmpfile(); if (!F) diff --git a/clang/test/Analysis/stream.c b/clang/test/Analysis/stream.c index e8f0692..36a9b4e 100644 --- a/clang/test/Analysis/stream.c +++ b/clang/test/Analysis/stream.c @@ -45,6 +45,12 @@ void check_fprintf(void) { fclose(fp); } +void check_fscanf(void) { + FILE *fp = tmpfile(); + fscanf(fp, "ABC"); // expected-warning {{Stream pointer might be NULL}} + fclose(fp); +} + void check_ungetc(void) { FILE *fp = tmpfile(); ungetc('A', fp); // expected-warning {{Stream pointer might be NULL}} |