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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2025 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/>.
*/
#include "checkvaarg.h"
#include "astutils.h"
#include "errortypes.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include <cstddef>
#include <iterator>
#include <list>
#include <vector>
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace {
CheckVaarg instance;
}
//---------------------------------------------------------------------------
// Ensure that correct parameter is passed to va_start()
//---------------------------------------------------------------------------
// CWE ids used:
static const CWE CWE664(664U); // Improper Control of a Resource Through its Lifetime
static const CWE CWE688(688U); // Function Call With Incorrect Variable or Reference as Argument
static const CWE CWE758(758U); // Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
void CheckVaarg::va_start_argument()
{
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
const std::size_t functions = symbolDatabase->functionScopes.size();
const bool printWarnings = mSettings->severity.isEnabled(Severity::warning);
logChecker("CheckVaarg::va_start_argument");
for (std::size_t i = 0; i < functions; ++i) {
const Scope* scope = symbolDatabase->functionScopes[i];
const Function* function = scope->function;
if (!function)
continue;
for (const Token* tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (!tok->scope()->isExecutable())
tok = tok->scope()->bodyEnd;
else if (Token::simpleMatch(tok, "va_start (")) {
const Token* param2 = tok->tokAt(2)->nextArgument();
if (!param2)
continue;
const Variable* var = param2->variable();
if (var && var->isReference())
referenceAs_va_start_error(param2, var->name());
if (var && var->index() + 2 < function->argCount() && printWarnings) {
auto it = function->argumentList.end();
std::advance(it, -2);
wrongParameterTo_va_start_error(tok, var->name(), it->name()); // cppcheck-suppress derefInvalidIterator // FP due to isVariableChangedByFunctionCall()
}
tok = tok->linkAt(1);
}
}
}
}
void CheckVaarg::wrongParameterTo_va_start_error(const Token *tok, const std::string& paramIsName, const std::string& paramShouldName)
{
reportError(tok, Severity::warning,
"va_start_wrongParameter", "'" + paramIsName + "' given to va_start() is not last named argument of the function. Did you intend to pass '" + paramShouldName + "'?", CWE688, Certainty::normal);
}
void CheckVaarg::referenceAs_va_start_error(const Token *tok, const std::string& paramName)
{
reportError(tok, Severity::error,
"va_start_referencePassed", "Using reference '" + paramName + "' as parameter for va_start() results in undefined behaviour.", CWE758, Certainty::normal);
}
//---------------------------------------------------------------------------
// Detect missing va_end() if va_start() was used
// Detect va_list usage after va_end()
//---------------------------------------------------------------------------
void CheckVaarg::va_list_usage()
{
if (mSettings->clang)
return;
logChecker("CheckVaarg::va_list_usage"); // notclang
const SymbolDatabase* const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Variable* var : symbolDatabase->variableList()) {
if (!var || var->isPointer() || var->isReference() || var->isArray() || !var->scope() || var->typeStartToken()->str() != "va_list")
continue;
if (!var->isLocal() && !var->isArgument()) // Check only local variables and arguments
continue;
bool open = var->isArgument(); // va_list passed as argument are opened
bool exitOnEndOfStatement = false;
const Token* tok = var->nameToken()->next();
for (; tok && tok != var->scope()->bodyEnd; tok = tok->next()) {
// Skip lambdas
const Token* tok2 = findLambdaEndToken(tok);
if (tok2)
tok = tok2;
if (Token::Match(tok, "va_start ( %varid%", var->declarationId())) {
if (open)
va_start_subsequentCallsError(tok, var->name());
open = true;
tok = tok->linkAt(1);
} else if (Token::Match(tok, "va_end ( %varid%", var->declarationId())) {
if (!open)
va_list_usedBeforeStartedError(tok, var->name());
open = false;
tok = tok->linkAt(1);
} else if (Token::simpleMatch(tok, "va_copy (")) {
bool nopen = open;
if (tok->linkAt(1)->previous()->varId() == var->declarationId()) { // Source
if (!open)
va_list_usedBeforeStartedError(tok, var->name());
}
if (tok->tokAt(2)->varId() == var->declarationId()) { // Destination
if (open)
va_start_subsequentCallsError(tok, var->name());
nopen = true;
}
open = nopen;
tok = tok->linkAt(1);
} else if (Token::Match(tok, "throw|return"))
exitOnEndOfStatement = true;
else if (tok->str() == "break") {
tok = findNextTokenFromBreak(tok);
if (!tok)
return;
} else if (tok->str() == "goto" || (tok->isCpp() && tok->str() == "try")) {
open = false;
break;
} else if (!open && tok->varId() == var->declarationId())
va_list_usedBeforeStartedError(tok, var->name());
else if (exitOnEndOfStatement && tok->str() == ";")
break;
}
if (open && !var->isArgument())
va_end_missingError(tok, var->name());
}
}
void CheckVaarg::va_end_missingError(const Token *tok, const std::string& varname)
{
reportError(tok, Severity::error,
"va_end_missing", "va_list '" + varname + "' was opened but not closed by va_end().", CWE664, Certainty::normal);
}
void CheckVaarg::va_list_usedBeforeStartedError(const Token *tok, const std::string& varname)
{
reportError(tok, Severity::error,
"va_list_usedBeforeStarted", "va_list '" + varname + "' used before va_start() was called.", CWE664, Certainty::normal);
}
void CheckVaarg::va_start_subsequentCallsError(const Token *tok, const std::string& varname)
{
reportError(tok, Severity::error,
"va_start_subsequentCalls", "va_start() or va_copy() called subsequently on '" + varname + "' without va_end() in between.", CWE664, Certainty::normal);
}
void CheckVaarg::runChecks(const Tokenizer &tokenizer, ErrorLogger *errorLogger)
{
CheckVaarg check(&tokenizer, &tokenizer.getSettings(), errorLogger);
check.va_start_argument();
check.va_list_usage();
}
void CheckVaarg::getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const
{
CheckVaarg c(nullptr, settings, errorLogger);
c.wrongParameterTo_va_start_error(nullptr, "arg1", "arg2");
c.referenceAs_va_start_error(nullptr, "arg1");
c.va_end_missingError(nullptr, "vl");
c.va_list_usedBeforeStartedError(nullptr, "vl");
c.va_start_subsequentCallsError(nullptr, "vl");
}
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