437 lines
22 KiB
C++
437 lines
22 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2018 Cppcheck team.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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//---------------------------------------------------------------------------
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// Check functions
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//---------------------------------------------------------------------------
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#include "checkfunctions.h"
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#include "astutils.h"
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#include "mathlib.h"
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#include "standards.h"
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#include "symboldatabase.h"
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#include "token.h"
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#include "tokenize.h"
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#include "valueflow.h"
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#include <cmath>
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#include <cstddef>
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#include <iomanip>
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#include <ostream>
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#include <vector>
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//---------------------------------------------------------------------------
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// Register this check class (by creating a static instance of it)
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namespace {
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CheckFunctions instance;
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}
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static const CWE CWE252(252U); // Unchecked Return Value
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static const CWE CWE477(477U); // Use of Obsolete Functions
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static const CWE CWE758(758U); // Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
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static const CWE CWE628(628U); // Function Call with Incorrectly Specified Arguments
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static const CWE CWE686(686U); // Function Call With Incorrect Argument Type
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static const CWE CWE687(687U); // Function Call With Incorrectly Specified Argument Value
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static const CWE CWE688(688U); // Function Call With Incorrect Variable or Reference as Argument
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void CheckFunctions::checkProhibitedFunctions()
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{
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const bool checkAlloca = mSettings->isEnabled(Settings::WARNING) && ((mSettings->standards.c >= Standards::C99 && mTokenizer->isC()) || mSettings->standards.cpp >= Standards::CPP11);
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope *scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
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if (!Token::Match(tok, "%name% (") && tok->varId() == 0)
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continue;
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// alloca() is special as it depends on the code being C or C++, so it is not in Library
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if (checkAlloca && Token::simpleMatch(tok, "alloca (") && (!tok->function() || tok->function()->nestedIn->type == Scope::eGlobal)) {
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if (mTokenizer->isC()) {
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if (mSettings->standards.c > Standards::C89)
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reportError(tok, Severity::warning, "allocaCalled",
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"$symbol:alloca\n"
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"Obsolete function 'alloca' called. In C99 and later it is recommended to use a variable length array instead.\n"
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"The obsolete function 'alloca' is called. In C99 and later it is recommended to use a variable length array or "
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"a dynamically allocated array instead. The function 'alloca' is dangerous for many reasons "
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"(http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice and http://linux.die.net/man/3/alloca).");
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} else
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reportError(tok, Severity::warning, "allocaCalled",
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"$symbol:alloca\n"
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"Obsolete function 'alloca' called.\n"
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"The obsolete function 'alloca' is called. In C++11 and later it is recommended to use std::array<> or "
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"a dynamically allocated array instead. The function 'alloca' is dangerous for many reasons "
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"(http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice and http://linux.die.net/man/3/alloca).");
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} else {
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if (tok->function() && tok->function()->hasBody())
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continue;
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const Library::WarnInfo* wi = mSettings->library.getWarnInfo(tok);
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if (wi) {
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if (mSettings->isEnabled(wi->severity) && mSettings->standards.c >= wi->standards.c && mSettings->standards.cpp >= wi->standards.cpp) {
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reportError(tok, wi->severity, tok->str() + "Called", wi->message, CWE477, false);
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}
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}
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}
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}
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}
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}
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//---------------------------------------------------------------------------
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// Check <valid> and <not-bool>
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//---------------------------------------------------------------------------
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void CheckFunctions::invalidFunctionUsage()
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{
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const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope *scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
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if (!Token::Match(tok, "%name% ( !!)"))
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continue;
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const Token * const functionToken = tok;
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const std::vector<const Token *> arguments = getArguments(tok);
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for (unsigned int argnr = 1; argnr <= arguments.size(); ++argnr) {
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const Token * const argtok = arguments[argnr-1];
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// check <valid>...</valid>
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const ValueFlow::Value *invalidValue = argtok->getInvalidValue(functionToken,argnr,mSettings);
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if (invalidValue) {
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invalidFunctionArgError(argtok, functionToken->next()->astOperand1()->expressionString(), argnr, invalidValue, mSettings->library.validarg(functionToken, argnr));
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}
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if (astIsBool(argtok)) {
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// check <not-bool>
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if (mSettings->library.isboolargbad(functionToken, argnr))
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invalidFunctionArgBoolError(argtok, functionToken->str(), argnr);
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// Are the values 0 and 1 valid?
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else if (!mSettings->library.isIntArgValid(functionToken, argnr, 0))
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invalidFunctionArgError(argtok, functionToken->str(), argnr, nullptr, mSettings->library.validarg(functionToken, argnr));
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else if (!mSettings->library.isIntArgValid(functionToken, argnr, 1))
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invalidFunctionArgError(argtok, functionToken->str(), argnr, nullptr, mSettings->library.validarg(functionToken, argnr));
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}
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}
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}
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}
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}
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void CheckFunctions::invalidFunctionArgError(const Token *tok, const std::string &functionName, int argnr, const ValueFlow::Value *invalidValue, const std::string &validstr)
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{
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std::ostringstream errmsg;
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errmsg << "$symbol:" << functionName << '\n';
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if (invalidValue && invalidValue->condition)
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errmsg << ValueFlow::eitherTheConditionIsRedundant(invalidValue->condition)
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<< " or $symbol() argument nr " << argnr << " can have invalid value.";
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else
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errmsg << "Invalid $symbol() argument nr " << argnr << '.';
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if (invalidValue)
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errmsg << " The value is " << std::setprecision(10) << (invalidValue->isIntValue() ? invalidValue->intvalue : invalidValue->floatValue) << " but the valid values are '" << validstr << "'.";
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else
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errmsg << " The value is 0 or 1 (boolean) but the valid values are '" << validstr << "'.";
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if (invalidValue)
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reportError(getErrorPath(tok, invalidValue, "Invalid argument"),
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invalidValue->errorSeverity() ? Severity::error : Severity::warning,
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"invalidFunctionArg",
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errmsg.str(),
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CWE628,
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invalidValue->isInconclusive());
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else
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reportError(tok,
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Severity::error,
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"invalidFunctionArg",
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errmsg.str(),
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CWE628,
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false);
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}
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void CheckFunctions::invalidFunctionArgBoolError(const Token *tok, const std::string &functionName, int argnr)
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{
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std::ostringstream errmsg;
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errmsg << "$symbol:" << functionName << '\n';
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errmsg << "Invalid $symbol() argument nr " << argnr << ". A non-boolean value is required.";
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reportError(tok, Severity::error, "invalidFunctionArgBool", errmsg.str(), CWE628, false);
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}
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//---------------------------------------------------------------------------
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// Check for ignored return values.
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//---------------------------------------------------------------------------
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void CheckFunctions::checkIgnoredReturnValue()
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{
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if (!mSettings->isEnabled(Settings::WARNING))
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return;
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope *scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
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// skip c++11 initialization, ({...})
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if (Token::Match(tok, "%var%|(|, {"))
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tok = tok->linkAt(1);
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else if (Token::Match(tok, "[(<]") && tok->link())
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tok = tok->link();
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if (tok->varId() || !Token::Match(tok, "%name% ("))
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continue;
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if (tok->next()->astParent())
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continue;
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if (!tok->scope()->isExecutable()) {
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tok = tok->scope()->bodyEnd;
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continue;
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}
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if ((!tok->function() || !Token::Match(tok->function()->retDef, "void %name%")) &&
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(mSettings->library.isUseRetVal(tok) || (tok->function() && tok->function()->isAttributeNodiscard())) &&
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!WRONG_DATA(!tok->next()->astOperand1(), tok)) {
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ignoredReturnValueError(tok, tok->next()->astOperand1()->expressionString());
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}
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}
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}
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}
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void CheckFunctions::ignoredReturnValueError(const Token* tok, const std::string& function)
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{
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reportError(tok, Severity::warning, "ignoredReturnValue",
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"$symbol:" + function + "\nReturn value of function $symbol() is not used.", CWE252, false);
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}
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//---------------------------------------------------------------------------
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// Detect passing wrong values to <cmath> functions like atan(0, x);
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//---------------------------------------------------------------------------
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void CheckFunctions::checkMathFunctions()
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{
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const bool styleC99 = mSettings->isEnabled(Settings::STYLE) && mSettings->standards.c != Standards::C89 && mSettings->standards.cpp != Standards::CPP03;
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const bool printWarnings = mSettings->isEnabled(Settings::WARNING);
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope *scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
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if (tok->varId())
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continue;
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if (printWarnings && Token::Match(tok, "%name% ( !!)")) {
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if (tok->strAt(-1) != "."
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&& Token::Match(tok, "log|logf|logl|log10|log10f|log10l ( %num% )")) {
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const std::string& number = tok->strAt(2);
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const bool isNegative = MathLib::isNegative(number);
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const bool isInt = MathLib::isInt(number);
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const bool isFloat = MathLib::isFloat(number);
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if (isNegative && isInt && MathLib::toLongNumber(number) <= 0) {
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mathfunctionCallWarning(tok); // case log(-2)
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} else if (isNegative && isFloat && MathLib::toDoubleNumber(number) <= 0.) {
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mathfunctionCallWarning(tok); // case log(-2.0)
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} else if (!isNegative && isFloat && MathLib::toDoubleNumber(number) <= 0.) {
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mathfunctionCallWarning(tok); // case log(0.0)
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} else if (!isNegative && isInt && MathLib::toLongNumber(number) <= 0) {
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mathfunctionCallWarning(tok); // case log(0)
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}
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}
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// atan2 ( x , y): x and y can not be zero, because this is mathematically not defined
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else if (Token::Match(tok, "atan2|atan2f|atan2l ( %num% , %num% )")) {
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if (MathLib::isNullValue(tok->strAt(2)) && MathLib::isNullValue(tok->strAt(4)))
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mathfunctionCallWarning(tok, 2);
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}
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// fmod ( x , y) If y is zero, then either a range error will occur or the function will return zero (implementation-defined).
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else if (Token::Match(tok, "fmod|fmodf|fmodl (")) {
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const Token* nextArg = tok->tokAt(2)->nextArgument();
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if (nextArg && nextArg->isNumber() && MathLib::isNullValue(nextArg->str()))
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mathfunctionCallWarning(tok, 2);
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}
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// pow ( x , y) If x is zero, and y is negative --> division by zero
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else if (Token::Match(tok, "pow|powf|powl ( %num% , %num% )")) {
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if (MathLib::isNullValue(tok->strAt(2)) && MathLib::isNegative(tok->strAt(4)))
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mathfunctionCallWarning(tok, 2);
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}
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}
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if (styleC99) {
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if (Token::Match(tok, "%num% - erf (") && Tokenizer::isOneNumber(tok->str()) && tok->next()->astOperand2() == tok->tokAt(3)) {
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mathfunctionCallWarning(tok, "1 - erf(x)", "erfc(x)");
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} else if (Token::simpleMatch(tok, "exp (") && Token::Match(tok->linkAt(1), ") - %num%") && Tokenizer::isOneNumber(tok->linkAt(1)->strAt(2)) && tok->linkAt(1)->next()->astOperand1() == tok->next()) {
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mathfunctionCallWarning(tok, "exp(x) - 1", "expm1(x)");
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} else if (Token::simpleMatch(tok, "log (") && tok->next()->astOperand2()) {
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const Token* plus = tok->next()->astOperand2();
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if (plus->str() == "+" && ((plus->astOperand1() && Tokenizer::isOneNumber(plus->astOperand1()->str())) || (plus->astOperand2() && Tokenizer::isOneNumber(plus->astOperand2()->str()))))
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mathfunctionCallWarning(tok, "log(1 + x)", "log1p(x)");
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}
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}
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}
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}
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}
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void CheckFunctions::mathfunctionCallWarning(const Token *tok, const unsigned int numParam)
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{
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if (tok) {
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if (numParam == 1)
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reportError(tok, Severity::warning, "wrongmathcall", "$symbol:" + tok->str() + "\nPassing value " + tok->strAt(2) + " to $symbol() leads to implementation-defined result.", CWE758, false);
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else if (numParam == 2)
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reportError(tok, Severity::warning, "wrongmathcall", "$symbol:" + tok->str() + "\nPassing values " + tok->strAt(2) + " and " + tok->strAt(4) + " to $symbol() leads to implementation-defined result.", CWE758, false);
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} else
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reportError(tok, Severity::warning, "wrongmathcall", "Passing value '#' to #() leads to implementation-defined result.", CWE758, false);
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}
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void CheckFunctions::mathfunctionCallWarning(const Token *tok, const std::string& oldexp, const std::string& newexp)
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{
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reportError(tok, Severity::style, "unpreciseMathCall", "Expression '" + oldexp + "' can be replaced by '" + newexp + "' to avoid loss of precision.", CWE758, false);
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}
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//---------------------------------------------------------------------------
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// memset(p, y, 0 /* bytes to fill */) <- 2nd and 3rd arguments inverted
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//---------------------------------------------------------------------------
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void CheckFunctions::memsetZeroBytes()
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{
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// FIXME:
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// Replace this with library configuration.
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// For instance:
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// <arg nr="3">
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// <warn knownIntValue="0" severity="warning" msg="..."/>
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// </arg>
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if (!mSettings->isEnabled(Settings::WARNING))
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return;
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope *scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
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if (Token::Match(tok, "memset|wmemset (") && (numberOfArguments(tok)==3)) {
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const std::vector<const Token *> &arguments = getArguments(tok);
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if (WRONG_DATA(arguments.size() != 3U, tok))
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continue;
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const Token* lastParamTok = arguments[2];
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if (lastParamTok->str() == "0")
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memsetZeroBytesError(tok);
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}
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}
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}
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}
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void CheckFunctions::memsetZeroBytesError(const Token *tok)
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{
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const std::string summary("memset() called to fill 0 bytes.");
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const std::string verbose(summary + " The second and third arguments might be inverted."
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" The function memset ( void * ptr, int value, size_t num ) sets the"
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" first num bytes of the block of memory pointed by ptr to the specified value.");
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reportError(tok, Severity::warning, "memsetZeroBytes", summary + "\n" + verbose, CWE687, false);
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}
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void CheckFunctions::memsetInvalid2ndParam()
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{
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// FIXME:
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// Replace this with library configuration.
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// For instance:
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// <arg nr="2">
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// <not-float/>
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// <warn possibleIntValue=":-129,256:" severity="warning" msg="..."/>
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// </arg>
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const bool printPortability = mSettings->isEnabled(Settings::PORTABILITY);
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const bool printWarning = mSettings->isEnabled(Settings::WARNING);
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if (!printWarning && !printPortability)
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return;
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const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
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for (const Scope *scope : symbolDatabase->functionScopes) {
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for (const Token* tok = scope->bodyStart->next(); tok && (tok != scope->bodyEnd); tok = tok->next()) {
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if (!Token::simpleMatch(tok, "memset ("))
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continue;
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const std::vector<const Token *> args = getArguments(tok);
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if (args.size() != 3)
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continue;
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// Second parameter is zero literal, i.e. 0.0f
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const Token * const secondParamTok = args[1];
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if (Token::Match(secondParamTok, "%num% ,") && MathLib::isNullValue(secondParamTok->str()))
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continue;
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// Check if second parameter is a float variable or a float literal != 0.0f
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if (printPortability && astIsFloat(secondParamTok,false)) {
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memsetFloatError(secondParamTok, secondParamTok->expressionString());
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}
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if (printWarning && secondParamTok->isNumber()) { // Check if the second parameter is a literal and is out of range
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const long long int value = MathLib::toLongNumber(secondParamTok->str());
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const long long sCharMin = mSettings->signedCharMin();
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const long long uCharMax = mSettings->unsignedCharMax();
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if (value < sCharMin || value > uCharMax)
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memsetValueOutOfRangeError(secondParamTok, secondParamTok->str());
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}
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}
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}
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}
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void CheckFunctions::memsetFloatError(const Token *tok, const std::string &var_value)
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{
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const std::string message("The 2nd memset() argument '" + var_value +
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"' is a float, its representation is implementation defined.");
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const std::string verbose(message + " memset() is used to set each byte of a block of memory to a specific value and"
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" the actual representation of a floating-point value is implementation defined.");
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reportError(tok, Severity::portability, "memsetFloat", message + "\n" + verbose, CWE688, false);
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}
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void CheckFunctions::memsetValueOutOfRangeError(const Token *tok, const std::string &value)
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{
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const std::string message("The 2nd memset() argument '" + value + "' doesn't fit into an 'unsigned char'.");
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const std::string verbose(message + " The 2nd parameter is passed as an 'int', but the function fills the block of memory using the 'unsigned char' conversion of this value.");
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reportError(tok, Severity::warning, "memsetValueOutOfRange", message + "\n" + verbose, CWE686, false);
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}
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//---------------------------------------------------------------------------
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// --check-library => warn for unconfigured functions
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//---------------------------------------------------------------------------
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void CheckFunctions::checkLibraryMatchFunctions()
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{
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if (!mSettings->checkLibrary || !mSettings->isEnabled(Settings::INFORMATION))
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return;
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bool New = false;
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for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
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if (!tok->scope() || !tok->scope()->isExecutable())
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continue;
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if (tok->str() == "new")
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New = true;
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else if (tok->str() == ";")
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New = false;
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else if (New)
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continue;
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if (!Token::Match(tok, "%name% (") || Token::Match(tok, "asm|sizeof|catch"))
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continue;
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if (tok->varId() != 0 || tok->type() || tok->isStandardType() || tok->isControlFlowKeyword())
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continue;
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if (tok->linkAt(1)->strAt(1) == "(")
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continue;
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if (!mSettings->library.isNotLibraryFunction(tok))
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continue;
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const std::string &functionName = mSettings->library.getFunctionName(tok);
|
|
if (functionName.empty() || mSettings->library.functions.find(functionName) != mSettings->library.functions.end())
|
|
continue;
|
|
|
|
reportError(tok,
|
|
Severity::information,
|
|
"checkLibraryFunction",
|
|
"--check-library: There is no matching configuration for function " + functionName + "()");
|
|
}
|
|
}
|