402 lines
18 KiB
C++
402 lines
18 KiB
C++
/*
|
|
* Cppcheck - A tool for static C/C++ code analysis
|
|
* Copyright (C) 2007-2015 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 "checksizeof.h"
|
|
#include "symboldatabase.h"
|
|
#include <algorithm>
|
|
#include <cctype>
|
|
//---------------------------------------------------------------------------
|
|
|
|
// Register this check class (by creating a static instance of it)
|
|
namespace {
|
|
CheckSizeof instance;
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
//---------------------------------------------------------------------------
|
|
void CheckSizeof::checkSizeofForNumericParameter()
|
|
{
|
|
if (!_settings->isEnabled("warning"))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
const std::size_t functions = symbolDatabase->functionScopes.size();
|
|
for (std::size_t i = 0; i < functions; ++i) {
|
|
const Scope * scope = symbolDatabase->functionScopes[i];
|
|
for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
|
|
if (Token::Match(tok, "sizeof ( %num% )") ||
|
|
Token::Match(tok, "sizeof %num%")) {
|
|
sizeofForNumericParameterError(tok);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckSizeof::sizeofForNumericParameterError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::warning,
|
|
"sizeofwithnumericparameter", "Suspicious usage of 'sizeof' with a numeric constant as parameter.\n"
|
|
"It is unusual to use a constant value with sizeof. For example, 'sizeof(10)'"
|
|
" returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 10. 'sizeof('A')'"
|
|
" and 'sizeof(char)' can return different results.");
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
//---------------------------------------------------------------------------
|
|
void CheckSizeof::checkSizeofForArrayParameter()
|
|
{
|
|
if (!_settings->isEnabled("warning"))
|
|
return;
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
const std::size_t functions = symbolDatabase->functionScopes.size();
|
|
for (std::size_t i = 0; i < functions; ++i) {
|
|
const Scope * scope = symbolDatabase->functionScopes[i];
|
|
for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
|
|
if (Token::Match(tok, "sizeof ( %var% )") ||
|
|
Token::Match(tok, "sizeof %var% !![")) {
|
|
const Token* varTok = tok->next();
|
|
if (varTok->str() == "(") {
|
|
varTok = varTok->next();
|
|
}
|
|
|
|
const Variable *var = varTok->variable();
|
|
if (var && var->isArray() && var->isArgument() && !var->isReference())
|
|
sizeofForArrayParameterError(tok);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckSizeof::sizeofForArrayParameterError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::warning,
|
|
"sizeofwithsilentarraypointer", "Using 'sizeof' on array given as function argument "
|
|
"returns size of a pointer.\n"
|
|
"Using 'sizeof' for array given as function argument returns the size of a pointer. "
|
|
"It does not return the size of the whole array in bytes as might be "
|
|
"expected. For example, this code:\n"
|
|
" int f(char a[100]) {\n"
|
|
" return sizeof(a);\n"
|
|
" }\n"
|
|
"returns 4 (in 32-bit systems) or 8 (in 64-bit systems) instead of 100 (the "
|
|
"size of the array in bytes)."
|
|
);
|
|
}
|
|
|
|
void CheckSizeof::checkSizeofForPointerSize()
|
|
{
|
|
if (!_settings->isEnabled("warning"))
|
|
return;
|
|
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
const std::size_t functions = symbolDatabase->functionScopes.size();
|
|
for (std::size_t i = 0; i < functions; ++i) {
|
|
const Scope * scope = symbolDatabase->functionScopes[i];
|
|
for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
|
|
const Token* tokSize;
|
|
const Token* tokFunc;
|
|
const Token *variable = nullptr;
|
|
const Token *variable2 = nullptr;
|
|
|
|
// Find any function that may use sizeof on a pointer
|
|
// Once leaving those tests, it is mandatory to have:
|
|
// - variable matching the used pointer
|
|
// - tokVar pointing on the argument where sizeof may be used
|
|
if (Token::Match(tok, "%var% = malloc|alloca (")) {
|
|
variable = tok;
|
|
tokSize = tok->tokAt(4);
|
|
tokFunc = tok->tokAt(2);
|
|
} else if (Token::Match(tok, "%var% = calloc (")) {
|
|
variable = tok;
|
|
tokSize = tok->tokAt(4)->nextArgument();
|
|
tokFunc = tok->tokAt(2);
|
|
} else if (Token::Match(tok, "return malloc|alloca (")) {
|
|
tokSize = tok->tokAt(3);
|
|
tokFunc = tok->next();
|
|
} else if (Token::simpleMatch(tok, "return calloc (")) {
|
|
tokSize = tok->tokAt(3)->nextArgument();
|
|
tokFunc = tok->next();
|
|
} else if (Token::simpleMatch(tok, "memset (") && tok->strAt(-1) != ".") {
|
|
variable = tok->tokAt(2);
|
|
tokSize = variable->nextArgument();
|
|
if (tokSize)
|
|
tokSize = tokSize->nextArgument();
|
|
tokFunc = tok;
|
|
} else if (Token::Match(tok, "memcpy|memcmp|memmove|strncpy|strncmp|strncat (") && tok->strAt(-1) != ".") {
|
|
variable = tok->tokAt(2);
|
|
variable2 = variable->nextArgument();
|
|
if (!variable2)
|
|
continue;
|
|
tokSize = variable2->nextArgument();
|
|
tokFunc = tok;
|
|
} else {
|
|
continue;
|
|
}
|
|
|
|
if (tokFunc && tokSize) {
|
|
for (const Token* tok2 = tokSize; tok2 != tokFunc->linkAt(1); tok2 = tok2->next()) {
|
|
if (Token::simpleMatch(tok2, "/ sizeof"))
|
|
divideBySizeofError(tok2, tokFunc->str());
|
|
}
|
|
}
|
|
|
|
if (!variable || !tokSize)
|
|
continue;
|
|
|
|
while (Token::Match(variable, "%var% ::|."))
|
|
variable = variable->tokAt(2);
|
|
|
|
// Ensure the variables are in the symbol database
|
|
// Also ensure the variables are pointers
|
|
// Only keep variables which are pointers
|
|
const Variable *var = variable->variable();
|
|
if (!var || !var->isPointer() || var->isArray()) {
|
|
variable = 0;
|
|
}
|
|
|
|
if (variable2) {
|
|
var = variable2->variable();
|
|
if (!var || !var->isPointer() || var->isArray()) {
|
|
variable2 = 0;
|
|
}
|
|
}
|
|
|
|
// If there are no pointer variable at this point, there is
|
|
// no need to continue
|
|
if (variable == 0 && variable2 == 0) {
|
|
continue;
|
|
}
|
|
|
|
// Jump to the next sizeof token in the function and in the parameter
|
|
// This is to allow generic operations with sizeof
|
|
for (; tokSize && tokSize->str() != ")" && tokSize->str() != "," && tokSize->str() != "sizeof"; tokSize = tokSize->next()) {}
|
|
|
|
if (tokSize->str() != "sizeof")
|
|
continue;
|
|
|
|
if (Token::simpleMatch(tokSize, "sizeof ( &"))
|
|
tokSize = tokSize->tokAt(3);
|
|
else if (Token::Match(tokSize, "sizeof (|&"))
|
|
tokSize = tokSize->tokAt(2);
|
|
else
|
|
tokSize = tokSize->next();
|
|
|
|
while (Token::Match(tokSize, "%var% ::|."))
|
|
tokSize = tokSize->tokAt(2);
|
|
|
|
if (Token::Match(tokSize, "%var% [|("))
|
|
continue;
|
|
|
|
// Now check for the sizeof usage. Once here, everything using sizeof(varid) or sizeof(&varid)
|
|
// looks suspicious
|
|
// Do it for first variable
|
|
if (variable && tokSize->varId() == variable->varId())
|
|
sizeofForPointerError(variable, variable->str());
|
|
if (variable2 && tokSize->varId() == variable2->varId())
|
|
sizeofForPointerError(variable2, variable2->str());
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckSizeof::sizeofForPointerError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::warning, "pointerSize",
|
|
"Size of pointer '" + varname + "' used instead of size of its data.\n"
|
|
"Size of pointer '" + varname + "' used instead of size of its data. "
|
|
"This is likely to lead to a buffer overflow. You probably intend to "
|
|
"write 'sizeof(*" + varname + ")'.");
|
|
}
|
|
|
|
void CheckSizeof::divideBySizeofError(const Token *tok, const std::string &memfunc)
|
|
{
|
|
reportError(tok, Severity::warning, "sizeofDivisionMemfunc",
|
|
"Division by result of sizeof(). " + memfunc + "() expects a size in bytes, did you intend to multiply instead?");
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
//-----------------------------------------------------------------------------
|
|
void CheckSizeof::sizeofsizeof()
|
|
{
|
|
if (!_settings->isEnabled("warning"))
|
|
return;
|
|
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (Token::Match(tok, "sizeof (| sizeof")) {
|
|
sizeofsizeofError(tok);
|
|
tok = tok->next();
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckSizeof::sizeofsizeofError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::warning,
|
|
"sizeofsizeof", "Calling 'sizeof' on 'sizeof'.\n"
|
|
"Calling sizeof for 'sizeof looks like a suspicious code and "
|
|
"most likely there should be just one 'sizeof'. The current "
|
|
"code is equivalent to 'sizeof(size_t)'");
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
|
|
void CheckSizeof::sizeofCalculation()
|
|
{
|
|
if (!_settings->isEnabled("warning"))
|
|
return;
|
|
|
|
const bool printInconclusive = _settings->inconclusive;
|
|
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (Token::simpleMatch(tok, "sizeof (")) {
|
|
|
|
// ignore if the `sizeof` result is cast to void inside a macro, i.e. the calculation is
|
|
// expected to be parsed but skipped, such as in a disabled custom ASSERT() macro
|
|
if (tok->isExpandedMacro() && tok->previous()) {
|
|
const Token *cast_end = (tok->previous()->str() == "(") ? tok->previous() : tok;
|
|
if (Token::simpleMatch(cast_end->tokAt(-3), "( void )") ||
|
|
Token::simpleMatch(cast_end->tokAt(-1), "static_cast<void>")) {
|
|
continue;
|
|
}
|
|
}
|
|
|
|
const Token *argument = tok->next()->astOperand2();
|
|
if (argument && argument->isCalculation() && (!argument->isExpandedMacro() || printInconclusive))
|
|
sizeofCalculationError(argument, argument->isExpandedMacro());
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckSizeof::sizeofCalculationError(const Token *tok, bool inconclusive)
|
|
{
|
|
reportError(tok, Severity::warning,
|
|
"sizeofCalculation", "Found calculation inside sizeof().", 0U, inconclusive);
|
|
}
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// Check for code like sizeof()*sizeof() or sizeof(ptr)/value
|
|
//-----------------------------------------------------------------------------
|
|
void CheckSizeof::suspiciousSizeofCalculation()
|
|
{
|
|
if (!_settings->isEnabled("warning") || !_settings->inconclusive)
|
|
return;
|
|
|
|
// TODO: Use AST here. This should be possible as soon as sizeof without brackets is correctly parsed
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (Token::simpleMatch(tok, "sizeof (")) {
|
|
const Token* const end = tok->linkAt(1);
|
|
const Variable* var = end->previous()->variable();
|
|
if (end->strAt(-1) == "*" || (var && var->isPointer() && !var->isArray())) {
|
|
if (end->strAt(1) == "/")
|
|
divideSizeofError(tok);
|
|
} else if (Token::simpleMatch(end, ") * sizeof") && end->next()->astOperand1() == tok->next())
|
|
multiplySizeofError(tok);
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckSizeof::multiplySizeofError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::warning,
|
|
"multiplySizeof", "Multiplying sizeof() with sizeof() indicates a logic error.", 0U, true);
|
|
}
|
|
|
|
void CheckSizeof::divideSizeofError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::warning,
|
|
"divideSizeof", "Division of result of sizeof() on pointer type.\n"
|
|
"Division of result of sizeof() on pointer type. sizeof() returns the size of the pointer, "
|
|
"not the size of the memory area it points to.", 0U, true);
|
|
}
|
|
|
|
void CheckSizeof::sizeofVoid()
|
|
{
|
|
if (!_settings->isEnabled("portability"))
|
|
return;
|
|
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
|
|
if (Token::simpleMatch(tok, "sizeof ( )")) { // "sizeof(void)" gets simplified to sizeof ( )
|
|
sizeofVoidError(tok);
|
|
} else if (Token::Match(tok, "sizeof ( * %var% )") && tok->tokAt(3)->variable() &&
|
|
(Token::Match(tok->tokAt(3)->variable()->typeStartToken(), "void * !!*")) &&
|
|
(!tok->tokAt(3)->variable()->isArray())) { // sizeof(*p) where p is of type "void*"
|
|
sizeofDereferencedVoidPointerError(tok, tok->strAt(3));
|
|
} else if (Token::Match(tok, "%name% +|-|++|--") ||
|
|
Token::Match(tok, "+|-|++|-- %name%")) { // Arithmetic operations on variable of type "void*"
|
|
const int index = (tok->isName()) ? 0 : 1;
|
|
const Variable* var = tok->tokAt(index)->variable();
|
|
if (var && !var->isArray() && Token::Match(var->typeStartToken(), "void * !!*")) {
|
|
std::string varname = tok->strAt(index);
|
|
// In case this 'void *' var is a member then go back to the main object
|
|
const Token* tok2 = tok->tokAt(index);
|
|
if (index == 0) {
|
|
bool isMember = false;
|
|
while (Token::simpleMatch(tok2->previous(), ".")) {
|
|
isMember = true;
|
|
if (Token::simpleMatch(tok2->tokAt(-2), ")"))
|
|
tok2 = tok2->linkAt(-2);
|
|
else if (Token::simpleMatch(tok2->tokAt(-2), "]"))
|
|
tok2 = tok2->linkAt(-2)->previous();
|
|
else
|
|
tok2 = tok2->tokAt(-2);
|
|
}
|
|
if (isMember) {
|
|
// Get 'struct.member' complete name (without spaces)
|
|
varname = tok2->stringifyList(tok->next());
|
|
varname.erase(std::remove_if(varname.begin(), varname.end(),
|
|
static_cast<int (*)(int)>(std::isspace)), varname.end());
|
|
}
|
|
}
|
|
// Check for cast on operations with '+|-'
|
|
if (Token::Match(tok, "%name% +|-")) {
|
|
// Check for cast expression
|
|
if (Token::simpleMatch(tok2->previous(), ")") && !Token::Match(tok2->previous()->link(), "( const| void *"))
|
|
continue;
|
|
if (tok2->strAt(-1) == "&") // Check for reference operator
|
|
continue;
|
|
}
|
|
arithOperationsOnVoidPointerError(tok, varname,
|
|
var->typeStartToken()->stringifyList(var->typeEndToken()->next()));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckSizeof::sizeofVoidError(const Token *tok)
|
|
{
|
|
const std::string message = "Behaviour of 'sizeof(void)' is not covered by the ISO C standard.";
|
|
const std::string verbose = message + " A value for 'sizeof(void)' is defined only as part of a GNU C extension, which defines 'sizeof(void)' to be 1.";
|
|
reportError(tok, Severity::portability, "sizeofVoid", message + "\n" + verbose);
|
|
}
|
|
|
|
void CheckSizeof::sizeofDereferencedVoidPointerError(const Token *tok, const std::string &varname)
|
|
{
|
|
const std::string message = "'*" + varname + "' is of type 'void', the behaviour of 'sizeof(void)' is not covered by the ISO C standard.";
|
|
const std::string verbose = message + " A value for 'sizeof(void)' is defined only as part of a GNU C extension, which defines 'sizeof(void)' to be 1.";
|
|
reportError(tok, Severity::portability, "sizeofDereferencedVoidPointer", message + "\n" + verbose);
|
|
}
|
|
|
|
void CheckSizeof::arithOperationsOnVoidPointerError(const Token* tok, const std::string &varname, const std::string &vartype)
|
|
{
|
|
const std::string message = "'" + varname + "' is of type '" + vartype + "'. When using void pointers in calculations, the behaviour is undefined.";
|
|
const std::string verbose = message + " Arithmetic operations on 'void *' is a GNU C extension, which defines the 'sizeof(void)' to be 1.";
|
|
reportError(tok, Severity::portability, "arithOperationsOnVoidPointer", message + "\n" + verbose);
|
|
}
|