791 lines
33 KiB
C++
791 lines
33 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2023 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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// Auto variables checks
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//---------------------------------------------------------------------------
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#include "checkautovariables.h"
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#include "astutils.h"
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#include "library.h"
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#include "settings.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 "vfvalue.h"
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#include <algorithm>
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#include <list>
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#include <unordered_set>
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#include <utility>
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#include <vector>
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//---------------------------------------------------------------------------
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// Register this check class into cppcheck by creating a static instance of it..
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namespace {
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CheckAutoVariables instance;
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}
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static const CWE CWE398(398U); // Indicator of Poor Code Quality
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static const CWE CWE562(562U); // Return of Stack Variable Address
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static const CWE CWE590(590U); // Free of Memory not on the Heap
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static bool isPtrArg(const Token *tok)
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{
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const Variable *var = tok->variable();
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return (var && var->isArgument() && var->isPointer());
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}
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static bool isArrayArg(const Token *tok, const Settings* settings)
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{
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const Variable *var = tok->variable();
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return (var && var->isArgument() && var->isArray() && !settings->library.isentrypoint(var->scope()->className));
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}
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static bool isArrayVar(const Token *tok)
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{
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const Variable *var = tok->variable();
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return (var && var->isArray() && !var->isArgument());
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}
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static bool isRefPtrArg(const Token *tok)
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{
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const Variable *var = tok->variable();
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return (var && var->isArgument() && var->isReference() && var->isPointer());
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}
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static bool isNonReferenceArg(const Token *tok)
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{
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const Variable *var = tok->variable();
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return (var && var->isArgument() && !var->isReference() && (var->isPointer() || (var->valueType() && var->valueType()->type >= ValueType::Type::CONTAINER) || var->type()));
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}
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static bool isAutoVar(const Token *tok)
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{
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const Variable *var = tok->variable();
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if (!var || !var->isLocal() || var->isStatic())
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return false;
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if (var->isReference()) {
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// address of reference variable can be taken if the address
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// of the variable it points at is not a auto-var
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// TODO: check what the reference variable references.
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return false;
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}
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if (Token::Match(tok, "%name% .|::")) {
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do {
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tok = tok->tokAt(2);
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} while (Token::Match(tok, "%name% .|::"));
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if (Token::Match(tok, "%name% ("))
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return false;
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}
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return true;
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}
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static bool isAutoVarArray(const Token *tok)
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{
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if (!tok)
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return false;
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// &x[..]
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if (tok->isUnaryOp("&") && Token::simpleMatch(tok->astOperand1(), "["))
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return isAutoVarArray(tok->astOperand1()->astOperand1());
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// x+y
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if (tok->str() == "+")
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return isAutoVarArray(tok->astOperand1()) || isAutoVarArray(tok->astOperand2());
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// x-intexpr
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if (tok->str() == "-")
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return isAutoVarArray(tok->astOperand1()) &&
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tok->astOperand2() &&
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tok->astOperand2()->valueType() &&
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tok->astOperand2()->valueType()->isIntegral();
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const Variable *var = tok->variable();
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if (!var)
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return false;
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// Variable
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if (var->isLocal() && !var->isStatic() && var->isArray() && !var->isPointer())
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return true;
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// ValueFlow
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if (var->isPointer() && !var->isArgument()) {
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for (std::list<ValueFlow::Value>::const_iterator it = tok->values().cbegin(); it != tok->values().cend(); ++it) {
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const ValueFlow::Value &val = *it;
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if (val.isTokValue() && isAutoVarArray(val.tokvalue))
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return true;
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}
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}
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return false;
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}
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static bool isLocalContainerBuffer(const Token* tok)
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{
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if (!tok)
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return false;
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// x+y
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if (tok->str() == "+")
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return isLocalContainerBuffer(tok->astOperand1()) || isLocalContainerBuffer(tok->astOperand2());
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if (tok->str() != "(" || !Token::simpleMatch(tok->astOperand1(), "."))
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return false;
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tok = tok->astOperand1()->astOperand1();
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const Variable* var = tok->variable();
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if (!var || !var->isLocal() || var->isStatic())
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return false;
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const Library::Container::Yield yield = astContainerYield(tok);
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return yield == Library::Container::Yield::BUFFER || yield == Library::Container::Yield::BUFFER_NT;
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}
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static bool isAddressOfLocalVariable(const Token *expr)
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{
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if (!expr)
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return false;
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if (Token::Match(expr, "+|-"))
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return isAddressOfLocalVariable(expr->astOperand1()) || isAddressOfLocalVariable(expr->astOperand2());
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if (expr->isCast())
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return isAddressOfLocalVariable(expr->astOperand2() ? expr->astOperand2() : expr->astOperand1());
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if (expr->isUnaryOp("&")) {
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const Token *op = expr->astOperand1();
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bool deref = false;
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while (Token::Match(op, ".|[")) {
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if (op->originalName() == "->")
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return false;
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if (op->str() == "[")
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deref = true;
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op = op->astOperand1();
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}
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return op && isAutoVar(op) && (!deref || !op->variable()->isPointer());
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}
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return false;
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}
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static bool variableIsUsedInScope(const Token* start, nonneg int varId, const Scope *scope)
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{
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if (!start) // Ticket #5024
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return false;
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for (const Token *tok = start; tok && tok != scope->bodyEnd; tok = tok->next()) {
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if (tok->varId() == varId)
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return true;
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const Scope::ScopeType scopeType = tok->scope()->type;
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if (scopeType == Scope::eFor || scopeType == Scope::eDo || scopeType == Scope::eWhile) // In case of loops, better checking would be necessary
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return true;
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if (Token::simpleMatch(tok, "asm ("))
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return true;
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}
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return false;
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}
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void CheckAutoVariables::assignFunctionArg()
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{
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const bool printStyle = mSettings->severity.isEnabled(Severity::style);
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const bool printWarning = mSettings->severity.isEnabled(Severity::warning);
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if (!printStyle && !printWarning)
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return;
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logChecker("CheckAutoVariables::assignFunctionArg"); // style,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; tok && tok != scope->bodyEnd; tok = tok->next()) {
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// TODO: What happens if this is removed?
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if (tok->astParent())
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continue;
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if (!(tok->isAssignmentOp() || tok->tokType() == Token::eIncDecOp) || !Token::Match(tok->astOperand1(), "%var%"))
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continue;
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const Token* const vartok = tok->astOperand1();
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if (isNonReferenceArg(vartok) &&
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!Token::Match(vartok->next(), "= %varid% ;", vartok->varId()) &&
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!variableIsUsedInScope(Token::findsimplematch(vartok->next(), ";"), vartok->varId(), scope) &&
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!Token::findsimplematch(vartok, "goto", scope->bodyEnd)) {
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if (vartok->variable()->isPointer() && printWarning)
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errorUselessAssignmentPtrArg(vartok);
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else if (printStyle)
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errorUselessAssignmentArg(vartok);
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}
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}
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}
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}
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static bool isAutoVariableRHS(const Token* tok) {
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return isAddressOfLocalVariable(tok) || isAutoVarArray(tok) || isLocalContainerBuffer(tok);
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}
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static bool hasOverloadedAssignment(const Token* tok, bool c, bool& inconclusive)
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{
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inconclusive = false;
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if (c)
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return false;
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if (const ValueType* vt = tok->valueType()) {
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if (vt->pointer && !Token::simpleMatch(tok->astParent(), "*"))
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return false;
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if (vt->container && vt->container->stdStringLike)
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return true;
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if (vt->typeScope)
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return std::any_of(vt->typeScope->functionList.begin(), vt->typeScope->functionList.end(), [](const Function& f) { // TODO: compare argument type
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return f.name() == "operator=";
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});
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return false;
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}
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inconclusive = true;
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return true;
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}
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void CheckAutoVariables::autoVariables()
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{
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logChecker("CheckAutoVariables::autoVariables");
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const bool printInconclusive = mSettings->certainty.isEnabled(Certainty::inconclusive);
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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 && tok != scope->bodyEnd; tok = tok->next()) {
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// Skip lambda..
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if (const Token *lambdaEndToken = findLambdaEndToken(tok)) {
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tok = lambdaEndToken;
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continue;
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}
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// Critical assignment
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if (Token::Match(tok, "[;{}] %var% =") && isRefPtrArg(tok->next()) && isAutoVariableRHS(tok->tokAt(2)->astOperand2())) {
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checkAutoVariableAssignment(tok->next(), false);
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} else if (Token::Match(tok, "[;{}] * %var% =") && isPtrArg(tok->tokAt(2)) && isAutoVariableRHS(tok->tokAt(3)->astOperand2())) {
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const Token* lhs = tok->tokAt(2);
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bool inconclusive = false;
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if (!hasOverloadedAssignment(lhs, mTokenizer->isC(), inconclusive) || (printInconclusive && inconclusive))
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checkAutoVariableAssignment(tok->next(), inconclusive);
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tok = tok->tokAt(4);
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} else if (Token::Match(tok, "[;{}] %var% . %var% =") && isPtrArg(tok->next()) && isAutoVariableRHS(tok->tokAt(4)->astOperand2())) {
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const Token* lhs = tok->tokAt(3);
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bool inconclusive = false;
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if (!hasOverloadedAssignment(lhs, mTokenizer->isC(), inconclusive) || (printInconclusive && inconclusive))
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checkAutoVariableAssignment(tok->next(), inconclusive);
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tok = tok->tokAt(5);
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} else if (Token::Match(tok, "[;{}] %var% [") && Token::simpleMatch(tok->linkAt(2), "] =") &&
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(isPtrArg(tok->next()) || isArrayArg(tok->next(), mSettings)) &&
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isAutoVariableRHS(tok->linkAt(2)->next()->astOperand2())) {
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errorAutoVariableAssignment(tok->next(), false);
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}
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// Invalid pointer deallocation
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else if ((Token::Match(tok, "%name% ( %var%|%str% ) ;") && mSettings->library.getDeallocFuncInfo(tok)) ||
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(mTokenizer->isCPP() && Token::Match(tok, "delete [| ]| (| %var%|%str% !!["))) {
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tok = Token::findmatch(tok->next(), "%var%|%str%");
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if (Token::simpleMatch(tok->astParent(), "."))
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continue;
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if (isArrayVar(tok) || tok->tokType() == Token::eString)
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errorInvalidDeallocation(tok, nullptr);
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else if (tok->variable() && tok->variable()->isPointer()) {
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for (const ValueFlow::Value &v : tok->values()) {
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if (v.isImpossible())
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continue;
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if ((v.isTokValue() && (isArrayVar(v.tokvalue) || ((v.tokvalue->tokType() == Token::eString)))) ||
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(v.isLocalLifetimeValue() && v.lifetimeKind == ValueFlow::Value::LifetimeKind::Address && !Token::simpleMatch(v.tokvalue, "("))) {
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errorInvalidDeallocation(tok, &v);
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break;
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}
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}
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}
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} else if ((Token::Match(tok, "%name% ( & %var% ) ;") && mSettings->library.getDeallocFuncInfo(tok)) ||
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(mTokenizer->isCPP() && Token::Match(tok, "delete [| ]| (| & %var% !!["))) {
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tok = Token::findmatch(tok->next(), "%var%");
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if (isAutoVar(tok))
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errorInvalidDeallocation(tok, nullptr);
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}
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}
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}
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}
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bool CheckAutoVariables::checkAutoVariableAssignment(const Token *expr, bool inconclusive, const Token *startToken)
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{
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if (!startToken)
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startToken = Token::findsimplematch(expr, "=")->next();
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for (const Token *tok = startToken; tok; tok = tok->next()) {
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if (tok->str() == "}" && tok->scope()->type == Scope::ScopeType::eFunction)
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errorAutoVariableAssignment(expr, inconclusive);
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if (Token::Match(tok, "return|throw|break|continue")) {
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errorAutoVariableAssignment(expr, inconclusive);
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return true;
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}
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if (Token::simpleMatch(tok, "=")) {
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const Token *lhs = tok;
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while (Token::Match(lhs->previous(), "%name%|.|*|]")) {
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if (lhs->linkAt(-1))
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lhs = lhs->linkAt(-1);
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else
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lhs = lhs->previous();
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}
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const Token *e = expr;
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while (e->str() != "=" && lhs->str() == e->str()) {
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e = e->next();
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lhs = lhs->next();
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}
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if (lhs->str() == "=")
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return false;
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}
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if (Token::simpleMatch(tok, "if (")) {
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const Token *ifStart = tok->linkAt(1)->next();
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return checkAutoVariableAssignment(expr, inconclusive, ifStart) || checkAutoVariableAssignment(expr, inconclusive, ifStart->link()->next());
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}
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if (Token::simpleMatch(tok, "} else {"))
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tok = tok->linkAt(2);
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}
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return false;
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}
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//---------------------------------------------------------------------------
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void CheckAutoVariables::errorAutoVariableAssignment(const Token *tok, bool inconclusive)
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{
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if (!inconclusive) {
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reportError(tok, Severity::error, "autoVariables",
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"Address of local auto-variable assigned to a function parameter.\n"
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"Dangerous assignment - the function parameter is assigned the address of a local "
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"auto-variable. Local auto-variables are reserved from the stack which "
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"is freed when the function ends. So the pointer to a local variable "
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"is invalid after the function ends.", CWE562, Certainty::normal);
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} else {
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reportError(tok, Severity::error, "autoVariables",
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"Address of local auto-variable assigned to a function parameter.\n"
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"Function parameter is assigned the address of a local auto-variable. "
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"Local auto-variables are reserved from the stack which is freed when "
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"the function ends. The address is invalid after the function ends and it "
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"might 'leak' from the function through the parameter.",
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CWE562,
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Certainty::inconclusive);
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}
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}
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void CheckAutoVariables::errorUselessAssignmentArg(const Token *tok)
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{
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reportError(tok,
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Severity::style,
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"uselessAssignmentArg",
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"Assignment of function parameter has no effect outside the function.", CWE398, Certainty::normal);
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}
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void CheckAutoVariables::errorUselessAssignmentPtrArg(const Token *tok)
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{
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reportError(tok,
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Severity::warning,
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"uselessAssignmentPtrArg",
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"Assignment of function parameter has no effect outside the function. Did you forget dereferencing it?", CWE398, Certainty::normal);
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}
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bool CheckAutoVariables::diag(const Token* tokvalue)
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{
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if (!tokvalue)
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return true;
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return !mDiagDanglingTemp.insert(tokvalue).second;
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}
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//---------------------------------------------------------------------------
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static bool isInScope(const Token * tok, const Scope * scope)
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{
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if (!tok)
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return false;
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if (!scope)
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return false;
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const Variable * var = tok->variable();
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if (var && (var->isGlobal() || var->isStatic() || var->isExtern()))
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return false;
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if (tok->scope() && !tok->scope()->isClassOrStructOrUnion() && tok->scope()->isNestedIn(scope))
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return true;
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if (!var)
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return false;
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if (var->isArgument() && !var->isReference()) {
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const Scope * tokScope = tok->scope();
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if (!tokScope)
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return false;
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if (std::any_of(tokScope->nestedList.cbegin(), tokScope->nestedList.cend(), [&](const Scope* argScope) {
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return argScope && argScope->isNestedIn(scope);
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}))
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return true;
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}
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return false;
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}
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static bool isDeadScope(const Token * tok, const Scope * scope)
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{
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if (!tok)
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return false;
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if (!scope)
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return false;
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const Variable * var = tok->variable();
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if (var && (!var->isLocal() || var->isStatic() || var->isExtern()))
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return false;
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if (tok->scope() && tok->scope()->bodyEnd != scope->bodyEnd && precedes(tok->scope()->bodyEnd, scope->bodyEnd))
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return true;
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return false;
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}
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static int getPointerDepth(const Token *tok)
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{
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if (!tok)
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return 0;
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if (tok->valueType())
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return tok->valueType()->pointer;
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int n = 0;
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std::pair<const Token*, const Token*> decl = Token::typeDecl(tok);
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for (const Token* tok2 = decl.first; tok2 != decl.second; tok2 = tok2->next())
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if (Token::simpleMatch(tok2, "*"))
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n++;
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return n;
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}
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static bool isDeadTemporary(bool cpp, const Token* tok, const Token* expr, const Library* library)
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{
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if (!isTemporary(cpp, tok, library))
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return false;
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if (expr) {
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if (!precedes(nextAfterAstRightmostLeaf(tok->astTop()), nextAfterAstRightmostLeaf(expr->astTop())))
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return false;
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const Token* parent = tok->astParent();
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if (Token::simpleMatch(parent, "{") && Token::simpleMatch(parent->astParent(), ":"))
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parent = parent->astParent();
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// Is in a for loop
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if (astIsRHS(tok) && Token::simpleMatch(parent, ":") && Token::simpleMatch(parent->astParent(), "(") && Token::simpleMatch(parent->astParent()->previous(), "for (")) {
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const Token* braces = parent->astParent()->link()->next();
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|
if (precedes(braces, expr) && precedes(expr, braces->link()))
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static bool isEscapedReference(const Variable* var)
|
|
{
|
|
if (!var)
|
|
return false;
|
|
if (!var->isReference())
|
|
return false;
|
|
const Token * const varDeclEndToken = var->declEndToken();
|
|
if (!varDeclEndToken)
|
|
return false;
|
|
if (!Token::simpleMatch(varDeclEndToken, "="))
|
|
return false;
|
|
const Token* vartok = varDeclEndToken->astOperand2();
|
|
return !isTemporary(true, vartok, nullptr, false);
|
|
}
|
|
|
|
static bool isDanglingSubFunction(const Token* tokvalue, const Token* tok)
|
|
{
|
|
if (!tokvalue)
|
|
return false;
|
|
const Variable* var = tokvalue->variable();
|
|
if (!var->isLocal())
|
|
return false;
|
|
const Function* f = Scope::nestedInFunction(tok->scope());
|
|
if (!f)
|
|
return false;
|
|
const Token* parent = tokvalue->astParent();
|
|
while (parent && !Token::Match(parent->previous(), "%name% (")) {
|
|
parent = parent->astParent();
|
|
}
|
|
if (!Token::simpleMatch(parent, "("))
|
|
return false;
|
|
return exprDependsOnThis(parent);
|
|
}
|
|
|
|
static const Variable* getParentVar(const Token* tok)
|
|
{
|
|
if (!tok)
|
|
return nullptr;
|
|
if (Token::simpleMatch(tok, "."))
|
|
return getParentVar(tok->astOperand1());
|
|
return tok->variable();
|
|
}
|
|
|
|
static bool isAssignedToNonLocal(const Token* tok)
|
|
{
|
|
if (!Token::simpleMatch(tok->astParent(), "="))
|
|
return false;
|
|
if (!astIsRHS(tok))
|
|
return false;
|
|
const Variable* var = getParentVar(tok->astParent()->astOperand1());
|
|
if (!var)
|
|
return false;
|
|
return !var->isLocal() || var->isStatic();
|
|
}
|
|
|
|
void CheckAutoVariables::checkVarLifetimeScope(const Token * start, const Token * end)
|
|
{
|
|
const bool printInconclusive = mSettings->certainty.isEnabled(Certainty::inconclusive);
|
|
if (!start)
|
|
return;
|
|
const Scope * scope = start->scope();
|
|
if (!scope)
|
|
return;
|
|
// If the scope is not set correctly then skip checking it
|
|
if (scope->bodyStart != start)
|
|
return;
|
|
const bool returnRef = Function::returnsReference(scope->function);
|
|
for (const Token *tok = start; tok && tok != end; tok = tok->next()) {
|
|
// Return reference from function
|
|
if (returnRef && Token::simpleMatch(tok->astParent(), "return")) {
|
|
for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(tok, true)) {
|
|
if (!printInconclusive && lt.inconclusive)
|
|
continue;
|
|
const Variable* var = lt.token->variable();
|
|
if (var && !var->isGlobal() && !var->isStatic() && !var->isReference() && !var->isRValueReference() &&
|
|
isInScope(var->nameToken(), tok->scope())) {
|
|
errorReturnReference(tok, lt.errorPath, lt.inconclusive);
|
|
break;
|
|
}
|
|
if (isDeadTemporary(mTokenizer->isCPP(), lt.token, nullptr, &mSettings->library)) {
|
|
errorReturnTempReference(tok, lt.errorPath, lt.inconclusive);
|
|
break;
|
|
}
|
|
}
|
|
// Assign reference to non-local variable
|
|
} else if (Token::Match(tok->previous(), "&|&& %var% =") && tok->astParent() == tok->next() &&
|
|
tok->variable() && tok->variable()->nameToken() == tok &&
|
|
tok->variable()->declarationId() == tok->varId() && tok->variable()->isStatic() &&
|
|
!tok->variable()->isArgument()) {
|
|
ErrorPath errorPath;
|
|
const Variable *var = ValueFlow::getLifetimeVariable(tok, errorPath);
|
|
if (var && isInScope(var->nameToken(), tok->scope())) {
|
|
errorDanglingReference(tok, var, errorPath);
|
|
continue;
|
|
}
|
|
// Reference to temporary
|
|
} else if (tok->variable() && (tok->variable()->isReference() || tok->variable()->isRValueReference())) {
|
|
for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(getParentLifetime(tok))) {
|
|
if (!printInconclusive && lt.inconclusive)
|
|
continue;
|
|
const Token * tokvalue = lt.token;
|
|
if (isDeadTemporary(mTokenizer->isCPP(), tokvalue, tok, &mSettings->library)) {
|
|
errorDanglingTempReference(tok, lt.errorPath, lt.inconclusive);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
const bool escape = Token::simpleMatch(tok->astParent(), "throw") ||
|
|
(Token::simpleMatch(tok->astParent(), "return") && !Function::returnsStandardType(scope->function));
|
|
std::unordered_set<const Token*> exprs;
|
|
for (const ValueFlow::Value& val:tok->values()) {
|
|
if (!val.isLocalLifetimeValue() && !val.isSubFunctionLifetimeValue())
|
|
continue;
|
|
if (!printInconclusive && val.isInconclusive())
|
|
continue;
|
|
const Token* parent = getParentLifetime(mTokenizer->isCPP(), val.tokvalue, &mSettings->library);
|
|
if (!exprs.insert(parent).second)
|
|
continue;
|
|
for (const ValueFlow::LifetimeToken& lt : ValueFlow::getLifetimeTokens(parent, escape || isAssignedToNonLocal(tok))) {
|
|
const Token * tokvalue = lt.token;
|
|
if (val.isLocalLifetimeValue()) {
|
|
if (escape) {
|
|
if (getPointerDepth(tok) < getPointerDepth(tokvalue))
|
|
continue;
|
|
if (!ValueFlow::isLifetimeBorrowed(tok, mSettings))
|
|
continue;
|
|
if (tokvalue->exprId() == tok->exprId() && !(tok->variable() && tok->variable()->isArray()) &&
|
|
!astIsContainerView(tok->astParent()))
|
|
continue;
|
|
if ((tokvalue->variable() && !isEscapedReference(tokvalue->variable()) &&
|
|
isInScope(tokvalue->variable()->nameToken(), scope)) ||
|
|
isDeadTemporary(mTokenizer->isCPP(), tokvalue, nullptr, &mSettings->library)) {
|
|
errorReturnDanglingLifetime(tok, &val);
|
|
break;
|
|
}
|
|
} else if (tokvalue->variable() && isDeadScope(tokvalue->variable()->nameToken(), tok->scope())) {
|
|
errorInvalidLifetime(tok, &val);
|
|
break;
|
|
} else if (!tokvalue->variable() &&
|
|
isDeadTemporary(mTokenizer->isCPP(), tokvalue, tok, &mSettings->library)) {
|
|
if (!diag(tokvalue))
|
|
errorDanglingTemporaryLifetime(tok, &val, tokvalue);
|
|
break;
|
|
}
|
|
}
|
|
if (tokvalue->variable() && (isInScope(tokvalue->variable()->nameToken(), tok->scope()) ||
|
|
(val.isSubFunctionLifetimeValue() && isDanglingSubFunction(tokvalue, tok)))) {
|
|
const Variable * var = nullptr;
|
|
const Token * tok2 = tok;
|
|
if (Token::simpleMatch(tok->astParent(), "=")) {
|
|
if (astIsRHS(tok)) {
|
|
var = getParentVar(tok->astParent()->astOperand1());
|
|
tok2 = tok->astParent()->astOperand1();
|
|
}
|
|
} else if (tok->variable() && tok->variable()->declarationId() == tok->varId()) {
|
|
var = tok->variable();
|
|
}
|
|
if (!ValueFlow::isLifetimeBorrowed(tok, mSettings))
|
|
continue;
|
|
const Token* nextTok = nextAfterAstRightmostLeaf(tok->astTop());
|
|
if (!nextTok)
|
|
nextTok = tok->next();
|
|
if (var && !var->isLocal() && !var->isArgument() && !(val.tokvalue && val.tokvalue->variable() && val.tokvalue->variable()->isStatic()) &&
|
|
!isVariableChanged(nextTok,
|
|
tok->scope()->bodyEnd,
|
|
var->declarationId(),
|
|
var->isGlobal(),
|
|
mSettings,
|
|
mTokenizer->isCPP())) {
|
|
errorDanglngLifetime(tok2, &val);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
const Token *lambdaEndToken = findLambdaEndToken(tok);
|
|
if (lambdaEndToken) {
|
|
checkVarLifetimeScope(lambdaEndToken->link(), lambdaEndToken);
|
|
tok = lambdaEndToken;
|
|
}
|
|
if (tok->str() == "{" && tok->scope()) {
|
|
// Check functions in local classes
|
|
if (tok->scope()->type == Scope::eClass ||
|
|
tok->scope()->type == Scope::eStruct ||
|
|
tok->scope()->type == Scope::eUnion) {
|
|
for (const Function& f:tok->scope()->functionList) {
|
|
if (f.functionScope)
|
|
checkVarLifetimeScope(f.functionScope->bodyStart, f.functionScope->bodyEnd);
|
|
}
|
|
tok = tok->link();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckAutoVariables::checkVarLifetime()
|
|
{
|
|
logChecker("CheckAutoVariables::checkVarLifetime");
|
|
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
|
|
for (const Scope * scope : symbolDatabase->functionScopes) {
|
|
if (!scope->function)
|
|
continue;
|
|
checkVarLifetimeScope(scope->bodyStart, scope->bodyEnd);
|
|
}
|
|
}
|
|
|
|
void CheckAutoVariables::errorReturnDanglingLifetime(const Token *tok, const ValueFlow::Value *val)
|
|
{
|
|
const bool inconclusive = val ? val->isInconclusive() : false;
|
|
ErrorPath errorPath = val ? val->errorPath : ErrorPath();
|
|
std::string msg = "Returning " + lifetimeMessage(tok, val, errorPath);
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(errorPath, Severity::error, "returnDanglingLifetime", msg + " that will be invalid when returning.", CWE562, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckAutoVariables::errorInvalidLifetime(const Token *tok, const ValueFlow::Value* val)
|
|
{
|
|
const bool inconclusive = val ? val->isInconclusive() : false;
|
|
ErrorPath errorPath = val ? val->errorPath : ErrorPath();
|
|
std::string msg = "Using " + lifetimeMessage(tok, val, errorPath);
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(errorPath, Severity::error, "invalidLifetime", msg + " that is out of scope.", CWE562, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckAutoVariables::errorDanglingTemporaryLifetime(const Token* tok, const ValueFlow::Value* val, const Token* tempTok)
|
|
{
|
|
const bool inconclusive = val ? val->isInconclusive() : false;
|
|
ErrorPath errorPath = val ? val->errorPath : ErrorPath();
|
|
std::string msg = "Using " + lifetimeMessage(tok, val, errorPath);
|
|
errorPath.emplace_back(tempTok, "Temporary created here.");
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(errorPath,
|
|
Severity::error,
|
|
"danglingTemporaryLifetime",
|
|
msg + " that is a temporary.",
|
|
CWE562,
|
|
inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckAutoVariables::errorDanglngLifetime(const Token *tok, const ValueFlow::Value *val)
|
|
{
|
|
const bool inconclusive = val ? val->isInconclusive() : false;
|
|
ErrorPath errorPath = val ? val->errorPath : ErrorPath();
|
|
std::string tokName = tok ? tok->expressionString() : "x";
|
|
std::string msg = "Non-local variable '" + tokName + "' will use " + lifetimeMessage(tok, val, errorPath);
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(errorPath, Severity::error, "danglingLifetime", msg + ".", CWE562, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckAutoVariables::errorDanglingTempReference(const Token* tok, ErrorPath errorPath, bool inconclusive)
|
|
{
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(
|
|
errorPath, Severity::error, "danglingTempReference", "Using reference to dangling temporary.", CWE562, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckAutoVariables::errorReturnReference(const Token* tok, ErrorPath errorPath, bool inconclusive)
|
|
{
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(
|
|
errorPath, Severity::error, "returnReference", "Reference to local variable returned.", CWE562, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckAutoVariables::errorDanglingReference(const Token *tok, const Variable *var, ErrorPath errorPath)
|
|
{
|
|
std::string tokName = tok ? tok->str() : "x";
|
|
std::string varName = var ? var->name() : "y";
|
|
std::string msg = "Non-local reference variable '" + tokName + "' to local variable '" + varName + "'";
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(errorPath, Severity::error, "danglingReference", msg, CWE562, Certainty::normal);
|
|
}
|
|
|
|
void CheckAutoVariables::errorReturnTempReference(const Token* tok, ErrorPath errorPath, bool inconclusive)
|
|
{
|
|
errorPath.emplace_back(tok, "");
|
|
reportError(
|
|
errorPath, Severity::error, "returnTempReference", "Reference to temporary returned.", CWE562, inconclusive ? Certainty::inconclusive : Certainty::normal);
|
|
}
|
|
|
|
void CheckAutoVariables::errorInvalidDeallocation(const Token *tok, const ValueFlow::Value *val)
|
|
{
|
|
const Variable *var = val ? val->tokvalue->variable() : (tok ? tok->variable() : nullptr);
|
|
|
|
std::string type = "an auto-variable";
|
|
if (tok && tok->tokType() == Token::eString)
|
|
type = "a string literal";
|
|
else if (val && val->tokvalue->tokType() == Token::eString)
|
|
type = "a pointer pointing to a string literal";
|
|
else if (var) {
|
|
if (var->isGlobal())
|
|
type = "a global variable";
|
|
else if (var->isStatic())
|
|
type = "a static variable";
|
|
}
|
|
|
|
if (val)
|
|
type += " (" + val->tokvalue->str() + ")";
|
|
|
|
reportError(getErrorPath(tok, val, "Deallocating memory that was not dynamically allocated"),
|
|
Severity::error,
|
|
"autovarInvalidDeallocation",
|
|
"Deallocation of " + type + " results in undefined behaviour.\n"
|
|
"The deallocation of " + type + " results in undefined behaviour. You should only free memory "
|
|
"that has been allocated dynamically.", CWE590, Certainty::normal);
|
|
}
|