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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2018 Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
// Check functions
//---------------------------------------------------------------------------
#include "checkfunctions.h"
#include "astutils.h"
#include "mathlib.h"
#include "standards.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include "valueflow.h"
#include <cmath>
#include <cstddef>
#include <iomanip>
#include <ostream>
#include <vector>
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace {
CheckFunctions instance;
}
static const CWE CWE252(252U); // Unchecked Return Value
static const CWE CWE477(477U); // Use of Obsolete Functions
static const CWE CWE758(758U); // Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
static const CWE CWE628(628U); // Function Call with Incorrectly Specified Arguments
static const CWE CWE686(686U); // Function Call With Incorrect Argument Type
static const CWE CWE687(687U); // Function Call With Incorrectly Specified Argument Value
static const CWE CWE688(688U); // Function Call With Incorrect Variable or Reference as Argument
void CheckFunctions::checkProhibitedFunctions()
{
const bool checkAlloca = mSettings->isEnabled(Settings::WARNING) && ((mSettings->standards.c >= Standards::C99 && mTokenizer->isC()) || mSettings->standards.cpp >= Standards::CPP11);
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope *scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "%name% (") && tok->varId() == 0)
continue;
// alloca() is special as it depends on the code being C or C++, so it is not in Library
if (checkAlloca && Token::simpleMatch(tok, "alloca (") && (!tok->function() || tok->function()->nestedIn->type == Scope::eGlobal)) {
if (mTokenizer->isC()) {
if (mSettings->standards.c > Standards::C89)
reportError(tok, Severity::warning, "allocaCalled",
"$symbol:alloca\n"
"Obsolete function 'alloca' called. In C99 and later it is recommended to use a variable length array instead.\n"
"The obsolete function 'alloca' is called. In C99 and later it is recommended to use a variable length array or "
"a dynamically allocated array instead. The function 'alloca' is dangerous for many reasons "
"(http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice and http://linux.die.net/man/3/alloca).");
} else
reportError(tok, Severity::warning, "allocaCalled",
"$symbol:alloca\n"
"Obsolete function 'alloca' called.\n"
"The obsolete function 'alloca' is called. In C++11 and later it is recommended to use std::array<> or "
"a dynamically allocated array instead. The function 'alloca' is dangerous for many reasons "
"(http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice and http://linux.die.net/man/3/alloca).");
} else {
if (tok->function() && tok->function()->hasBody())
continue;
const Library::WarnInfo* wi = mSettings->library.getWarnInfo(tok);
if (wi) {
if (mSettings->isEnabled(wi->severity) && mSettings->standards.c >= wi->standards.c && mSettings->standards.cpp >= wi->standards.cpp) {
reportError(tok, wi->severity, tok->str() + "Called", wi->message, CWE477, false);
}
}
}
}
}
}
//---------------------------------------------------------------------------
// Check <valid> and <not-bool>
//---------------------------------------------------------------------------
void CheckFunctions::invalidFunctionUsage()
{
const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope *scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (!Token::Match(tok, "%name% ( !!)"))
continue;
const Token * const functionToken = tok;
const std::vector<const Token *> arguments = getArguments(tok);
for (unsigned int argnr = 1; argnr <= arguments.size(); ++argnr) {
const Token * const argtok = arguments[argnr-1];
// check <valid>...</valid>
const ValueFlow::Value *invalidValue = argtok->getInvalidValue(functionToken,argnr,mSettings);
if (invalidValue) {
invalidFunctionArgError(argtok, functionToken->next()->astOperand1()->expressionString(), argnr, invalidValue, mSettings->library.validarg(functionToken, argnr));
}
if (astIsBool(argtok)) {
// check <not-bool>
if (mSettings->library.isboolargbad(functionToken, argnr))
invalidFunctionArgBoolError(argtok, functionToken->str(), argnr);
// Are the values 0 and 1 valid?
else if (!mSettings->library.isIntArgValid(functionToken, argnr, 0))
invalidFunctionArgError(argtok, functionToken->str(), argnr, nullptr, mSettings->library.validarg(functionToken, argnr));
else if (!mSettings->library.isIntArgValid(functionToken, argnr, 1))
invalidFunctionArgError(argtok, functionToken->str(), argnr, nullptr, mSettings->library.validarg(functionToken, argnr));
}
if (mSettings->library.isargstrz(functionToken, argnr)) {
if (Token::Match(argtok, "& %var% !![") && argtok->next() && argtok->next()->valueType()) {
const ValueType * valueType = argtok->next()->valueType();
const Variable * variable = argtok->next()->variable();
if (valueType->type == ValueType::Type::CHAR && !variable->isArray() && !variable->isGlobal() &&
(!argtok->next()->hasKnownValue() || argtok->next()->getValue(0) == nullptr)) {
invalidFunctionArgStrError(argtok, functionToken->str(), argnr);
}
}
}
}
}
}
}
void CheckFunctions::invalidFunctionArgError(const Token *tok, const std::string &functionName, int argnr, const ValueFlow::Value *invalidValue, const std::string &validstr)
{
std::ostringstream errmsg;
errmsg << "$symbol:" << functionName << '\n';
if (invalidValue && invalidValue->condition)
errmsg << ValueFlow::eitherTheConditionIsRedundant(invalidValue->condition)
<< " or $symbol() argument nr " << argnr << " can have invalid value.";
else
errmsg << "Invalid $symbol() argument nr " << argnr << '.';
if (invalidValue)
errmsg << " The value is " << std::setprecision(10) << (invalidValue->isIntValue() ? invalidValue->intvalue : invalidValue->floatValue) << " but the valid values are '" << validstr << "'.";
else
errmsg << " The value is 0 or 1 (boolean) but the valid values are '" << validstr << "'.";
if (invalidValue)
reportError(getErrorPath(tok, invalidValue, "Invalid argument"),
invalidValue->errorSeverity() ? Severity::error : Severity::warning,
"invalidFunctionArg",
errmsg.str(),
CWE628,
invalidValue->isInconclusive());
else
reportError(tok,
Severity::error,
"invalidFunctionArg",
errmsg.str(),
CWE628,
false);
}
void CheckFunctions::invalidFunctionArgBoolError(const Token *tok, const std::string &functionName, int argnr)
{
std::ostringstream errmsg;
errmsg << "$symbol:" << functionName << '\n';
errmsg << "Invalid $symbol() argument nr " << argnr << ". A non-boolean value is required.";
reportError(tok, Severity::error, "invalidFunctionArgBool", errmsg.str(), CWE628, false);
}
void CheckFunctions::invalidFunctionArgStrError(const Token *tok, const std::string &functionName, unsigned int argnr)
{
std::ostringstream errmsg;
errmsg << "$symbol:" << functionName << '\n';
errmsg << "Invalid $symbol() argument nr " << argnr << ". A nul-terminated string is required.";
reportError(tok, Severity::error, "invalidFunctionArgStr", errmsg.str(), CWE628, false);
}
//---------------------------------------------------------------------------
// Check for ignored return values.
//---------------------------------------------------------------------------
void CheckFunctions::checkIgnoredReturnValue()
{
if (!mSettings->isEnabled(Settings::WARNING))
return;
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope *scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
// skip c++11 initialization, ({...})
if (Token::Match(tok, "%var%|(|, {"))
tok = tok->linkAt(1);
else if (Token::Match(tok, "[(<]") && tok->link())
tok = tok->link();
if (tok->varId() || !Token::Match(tok, "%name% ("))
continue;
if (tok->next()->astParent())
continue;
if (!tok->scope()->isExecutable()) {
tok = tok->scope()->bodyEnd;
continue;
}
if ((!tok->function() || !Token::Match(tok->function()->retDef, "void %name%")) &&
(mSettings->library.isUseRetVal(tok) || (tok->function() && tok->function()->isAttributeNodiscard())) &&
!WRONG_DATA(!tok->next()->astOperand1(), tok)) {
ignoredReturnValueError(tok, tok->next()->astOperand1()->expressionString());
}
}
}
}
void CheckFunctions::ignoredReturnValueError(const Token* tok, const std::string& function)
{
reportError(tok, Severity::warning, "ignoredReturnValue",
"$symbol:" + function + "\nReturn value of function $symbol() is not used.", CWE252, false);
}
//---------------------------------------------------------------------------
// Detect passing wrong values to <cmath> functions like atan(0, x);
//---------------------------------------------------------------------------
void CheckFunctions::checkMathFunctions()
{
const bool styleC99 = mSettings->isEnabled(Settings::STYLE) && mSettings->standards.c != Standards::C89 && mSettings->standards.cpp != Standards::CPP03;
const bool printWarnings = mSettings->isEnabled(Settings::WARNING);
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope *scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (tok->varId())
continue;
if (printWarnings && Token::Match(tok, "%name% ( !!)")) {
if (tok->strAt(-1) != "."
&& Token::Match(tok, "log|logf|logl|log10|log10f|log10l|log2|log2f|log2l ( %num% )")) {
const std::string& number = tok->strAt(2);
if ((MathLib::isInt(number) && MathLib::toLongNumber(number) <= 0) ||
(MathLib::isFloat(number) && MathLib::toDoubleNumber(number) <= 0.))
mathfunctionCallWarning(tok);
} else if (Token::Match(tok, "log1p|log1pf|log1pl ( %num% )")) {
const std::string& number = tok->strAt(2);
if ((MathLib::isInt(number) && MathLib::toLongNumber(number) <= -1) ||
(MathLib::isFloat(number) && MathLib::toDoubleNumber(number) <= -1.))
mathfunctionCallWarning(tok);
}
// atan2 ( x , y): x and y can not be zero, because this is mathematically not defined
else if (Token::Match(tok, "atan2|atan2f|atan2l ( %num% , %num% )")) {
if (MathLib::isNullValue(tok->strAt(2)) && MathLib::isNullValue(tok->strAt(4)))
mathfunctionCallWarning(tok, 2);
}
// fmod ( x , y) If y is zero, then either a range error will occur or the function will return zero (implementation-defined).
else if (Token::Match(tok, "fmod|fmodf|fmodl (")) {
const Token* nextArg = tok->tokAt(2)->nextArgument();
if (nextArg && nextArg->isNumber() && MathLib::isNullValue(nextArg->str()))
mathfunctionCallWarning(tok, 2);
}
// pow ( x , y) If x is zero, and y is negative --> division by zero
else if (Token::Match(tok, "pow|powf|powl ( %num% , %num% )")) {
if (MathLib::isNullValue(tok->strAt(2)) && MathLib::isNegative(tok->strAt(4)))
mathfunctionCallWarning(tok, 2);
}
}
if (styleC99) {
if (Token::Match(tok, "%num% - erf (") && Tokenizer::isOneNumber(tok->str()) && tok->next()->astOperand2() == tok->tokAt(3)) {
mathfunctionCallWarning(tok, "1 - erf(x)", "erfc(x)");
} 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()) {
mathfunctionCallWarning(tok, "exp(x) - 1", "expm1(x)");
} else if (Token::simpleMatch(tok, "log (") && tok->next()->astOperand2()) {
const Token* plus = tok->next()->astOperand2();
if (plus->str() == "+" && ((plus->astOperand1() && Tokenizer::isOneNumber(plus->astOperand1()->str())) || (plus->astOperand2() && Tokenizer::isOneNumber(plus->astOperand2()->str()))))
mathfunctionCallWarning(tok, "log(1 + x)", "log1p(x)");
}
}
}
}
}
void CheckFunctions::mathfunctionCallWarning(const Token *tok, const unsigned int numParam)
{
if (tok) {
if (numParam == 1)
reportError(tok, Severity::warning, "wrongmathcall", "$symbol:" + tok->str() + "\nPassing value " + tok->strAt(2) + " to $symbol() leads to implementation-defined result.", CWE758, false);
else if (numParam == 2)
reportError(tok, Severity::warning, "wrongmathcall", "$symbol:" + tok->str() + "\nPassing values " + tok->strAt(2) + " and " + tok->strAt(4) + " to $symbol() leads to implementation-defined result.", CWE758, false);
} else
reportError(tok, Severity::warning, "wrongmathcall", "Passing value '#' to #() leads to implementation-defined result.", CWE758, false);
}
void CheckFunctions::mathfunctionCallWarning(const Token *tok, const std::string& oldexp, const std::string& newexp)
{
reportError(tok, Severity::style, "unpreciseMathCall", "Expression '" + oldexp + "' can be replaced by '" + newexp + "' to avoid loss of precision.", CWE758, false);
}
//---------------------------------------------------------------------------
// memset(p, y, 0 /* bytes to fill */) <- 2nd and 3rd arguments inverted
//---------------------------------------------------------------------------
void CheckFunctions::memsetZeroBytes()
{
// FIXME:
// Replace this with library configuration.
// For instance:
// <arg nr="3">
// <warn knownIntValue="0" severity="warning" msg="..."/>
// </arg>
if (!mSettings->isEnabled(Settings::WARNING))
return;
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope *scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "memset|wmemset (") && (numberOfArguments(tok)==3)) {
const std::vector<const Token *> &arguments = getArguments(tok);
if (WRONG_DATA(arguments.size() != 3U, tok))
continue;
const Token* lastParamTok = arguments[2];
if (lastParamTok->str() == "0")
memsetZeroBytesError(tok);
}
}
}
}
void CheckFunctions::memsetZeroBytesError(const Token *tok)
{
const std::string summary("memset() called to fill 0 bytes.");
const std::string verbose(summary + " The second and third arguments might be inverted."
" The function memset ( void * ptr, int value, size_t num ) sets the"
" first num bytes of the block of memory pointed by ptr to the specified value.");
reportError(tok, Severity::warning, "memsetZeroBytes", summary + "\n" + verbose, CWE687, false);
}
void CheckFunctions::memsetInvalid2ndParam()
{
// FIXME:
// Replace this with library configuration.
// For instance:
// <arg nr="2">
// <not-float/>
// <warn possibleIntValue=":-129,256:" severity="warning" msg="..."/>
// </arg>
const bool printPortability = mSettings->isEnabled(Settings::PORTABILITY);
const bool printWarning = mSettings->isEnabled(Settings::WARNING);
if (!printWarning && !printPortability)
return;
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope *scope : symbolDatabase->functionScopes) {
for (const Token* tok = scope->bodyStart->next(); tok && (tok != scope->bodyEnd); tok = tok->next()) {
if (!Token::simpleMatch(tok, "memset ("))
continue;
const std::vector<const Token *> args = getArguments(tok);
if (args.size() != 3)
continue;
// Second parameter is zero literal, i.e. 0.0f
const Token * const secondParamTok = args[1];
if (Token::Match(secondParamTok, "%num% ,") && MathLib::isNullValue(secondParamTok->str()))
continue;
// Check if second parameter is a float variable or a float literal != 0.0f
if (printPortability && astIsFloat(secondParamTok,false)) {
memsetFloatError(secondParamTok, secondParamTok->expressionString());
}
if (printWarning && secondParamTok->isNumber()) { // Check if the second parameter is a literal and is out of range
const long long int value = MathLib::toLongNumber(secondParamTok->str());
const long long sCharMin = mSettings->signedCharMin();
const long long uCharMax = mSettings->unsignedCharMax();
if (value < sCharMin || value > uCharMax)
memsetValueOutOfRangeError(secondParamTok, secondParamTok->str());
}
}
}
}
void CheckFunctions::memsetFloatError(const Token *tok, const std::string &var_value)
{
const std::string message("The 2nd memset() argument '" + var_value +
"' is a float, its representation is implementation defined.");
const std::string verbose(message + " memset() is used to set each byte of a block of memory to a specific value and"
" the actual representation of a floating-point value is implementation defined.");
reportError(tok, Severity::portability, "memsetFloat", message + "\n" + verbose, CWE688, false);
}
void CheckFunctions::memsetValueOutOfRangeError(const Token *tok, const std::string &value)
{
const std::string message("The 2nd memset() argument '" + value + "' doesn't fit into an 'unsigned char'.");
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.");
reportError(tok, Severity::warning, "memsetValueOutOfRange", message + "\n" + verbose, CWE686, false);
}
//---------------------------------------------------------------------------
// --check-library => warn for unconfigured functions
//---------------------------------------------------------------------------
void CheckFunctions::checkLibraryMatchFunctions()
{
if (!mSettings->checkLibrary || !mSettings->isEnabled(Settings::INFORMATION))
return;
bool New = false;
for (const Token *tok = mTokenizer->tokens(); tok; tok = tok->next()) {
if (!tok->scope() || !tok->scope()->isExecutable())
continue;
if (tok->str() == "new")
New = true;
else if (tok->str() == ";")
New = false;
else if (New)
continue;
if (!Token::Match(tok, "%name% (") || Token::Match(tok, "asm|sizeof|catch"))
continue;
if (tok->varId() != 0 || tok->type() || tok->isStandardType() || tok->isControlFlowKeyword())
continue;
if (tok->linkAt(1)->strAt(1) == "(")
continue;
if (!mSettings->library.isNotLibraryFunction(tok))
continue;
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 + "()");
}
}