cppcheck/lib/checkvaarg.cpp at main · cppcheck-opensource/cppcheck · GitHub

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* Cppcheck - A tool for static C/C++ code analysis

* 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>

//---------------------------------------------------------------------------

// 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 CheckVaargImpl::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());

}

tok = tok->linkAt(1);

}

void CheckVaargImpl::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 CheckVaargImpl::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 CheckVaargImpl::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 CheckVaargImpl::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 CheckVaargImpl::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 CheckVaargImpl::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)

{

CheckVaargImpl check(&tokenizer, tokenizer.getSettings(), errorLogger);

check.va_start_argument();

check.va_list_usage();

}

void CheckVaarg::getErrorMessages(ErrorLogger& errorLogger, const Settings &settings) const

{

CheckVaargImpl 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");

}

cppcheck/lib/checkvaarg.cpp at main · cppcheck-opensource/cppcheck · GitHub

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