624 lines
19 KiB
C++
624 lines
19 KiB
C++
/*
|
|
* Cppcheck - A tool for static C/C++ code analysis
|
|
* Copyright (C) 2007-2009 Daniel Marjamäki, Reijo Tomperi, Nicolas Le Cam,
|
|
* Leandro Penz, Kimmo Varis, Vesa Pikki
|
|
*
|
|
* 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/
|
|
*/
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Buffer overrun..
|
|
//---------------------------------------------------------------------------
|
|
|
|
#include "checkbufferoverrun.h"
|
|
|
|
#include "tokenize.h"
|
|
#include "errorlogger.h"
|
|
|
|
#include <algorithm>
|
|
#include <sstream>
|
|
#include <list>
|
|
#include <cstring>
|
|
|
|
|
|
#include <cstdlib> // <- strtoul
|
|
|
|
//---------------------------------------------------------------------------
|
|
|
|
// Register this check class (by creating a static instance of it)
|
|
namespace
|
|
{
|
|
CheckBufferOverrunClass instance;
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckBufferOverrunClass::arrayIndexOutOfBounds(const Token *tok)
|
|
{
|
|
_callStack.push_back(tok);
|
|
arrayIndexOutOfBounds();
|
|
_callStack.pop_back();
|
|
}
|
|
|
|
void CheckBufferOverrunClass::arrayIndexOutOfBounds()
|
|
{
|
|
reportError(_callStack, "all", "arrayIndexOutOfBounds", "Array index out of bounds");
|
|
}
|
|
|
|
void CheckBufferOverrunClass::bufferOverrun(const Token *tok)
|
|
{
|
|
reportError(tok, "all", "bufferOverrun", "Buffer overrun");
|
|
}
|
|
|
|
void CheckBufferOverrunClass::strncatUsage(const Token *tok)
|
|
{
|
|
reportError(tok, "all", "strncatUsage", "Dangerous usage of strncat, possible buffer overrun");
|
|
}
|
|
|
|
void CheckBufferOverrunClass::outOfBounds(const Token *tok, const std::string &what)
|
|
{
|
|
reportError(tok, "error", "outOfBounds", what + " is out of bounds");
|
|
}
|
|
|
|
void CheckBufferOverrunClass::sizeArgumentAsChar(const Token *tok)
|
|
{
|
|
reportError(tok, "all", "sizeArgumentAsChar", "The size argument is given as a char constant");
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Check array usage..
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckBufferOverrunClass::CheckBufferOverrun_CheckScope(const Token *tok, const char *varname[], const int size, const int total_size, unsigned int varid)
|
|
{
|
|
unsigned int varc = 0;
|
|
|
|
std::string varnames;
|
|
while (varname[varc])
|
|
{
|
|
if (varc > 0)
|
|
varnames += " . ";
|
|
|
|
varnames += varname[varc];
|
|
|
|
++varc;
|
|
}
|
|
|
|
if (varc == 0)
|
|
varc = 1;
|
|
|
|
varc = 2 * (varc - 1);
|
|
|
|
// Array index..
|
|
if (varid > 0)
|
|
{
|
|
if (Token::Match(tok, "%varid% [ %num% ]", varid))
|
|
{
|
|
const char *num = tok->strAt(2);
|
|
if (std::strtol(num, NULL, 10) >= size)
|
|
{
|
|
arrayIndexOutOfBounds(tok->next());
|
|
}
|
|
}
|
|
}
|
|
else if (Token::Match(tok, std::string(varnames + " [ %num% ]").c_str()))
|
|
{
|
|
const char *num = tok->strAt(2 + varc);
|
|
if (std::strtol(num, NULL, 10) >= size)
|
|
{
|
|
arrayIndexOutOfBounds(tok->next());
|
|
}
|
|
}
|
|
|
|
int indentlevel = 0;
|
|
for (; tok; tok = tok->next())
|
|
{
|
|
if (tok->str() == "{")
|
|
{
|
|
++indentlevel;
|
|
}
|
|
|
|
else if (tok->str() == "}")
|
|
{
|
|
--indentlevel;
|
|
if (indentlevel < 0)
|
|
return;
|
|
}
|
|
|
|
// Array index..
|
|
if (varid > 0)
|
|
{
|
|
if (!tok->isName() && !Token::Match(tok, "[.&]") && Token::Match(tok->next(), "%varid% [ %num% ]", varid))
|
|
{
|
|
const char *num = tok->strAt(3);
|
|
if (std::strtol(num, NULL, 10) >= size)
|
|
{
|
|
arrayIndexOutOfBounds(tok->next());
|
|
}
|
|
}
|
|
}
|
|
else if (!tok->isName() && !Token::Match(tok, "[.&]") && Token::Match(tok->next(), std::string(varnames + " [ %num% ]").c_str()))
|
|
{
|
|
const char *num = tok->next()->strAt(2 + varc);
|
|
if (std::strtol(num, NULL, 10) >= size)
|
|
{
|
|
arrayIndexOutOfBounds(tok->next());
|
|
}
|
|
tok = tok->tokAt(4);
|
|
continue;
|
|
}
|
|
|
|
|
|
// memset, memcmp, memcpy, strncpy, fgets..
|
|
if (varid > 0)
|
|
{
|
|
if (Token::Match(tok, "memset|memcpy|memmove|memcmp|strncpy|fgets"))
|
|
{
|
|
if (Token::Match(tok->next(), "( %varid% , %any% , %any% )", varid) ||
|
|
Token::Match(tok->next(), "( %var% , %varid% , %any% )", varid))
|
|
{
|
|
const Token *tokSz = tok->tokAt(6);
|
|
if (tokSz->str()[0] == '\'')
|
|
sizeArgumentAsChar(tok);
|
|
else if (tokSz->isNumber())
|
|
{
|
|
const char *num = tok->strAt(6);
|
|
if (std::atoi(num) > total_size)
|
|
{
|
|
bufferOverrun(tok);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
else if (Token::Match(tok, "memset|memcpy|memmove|memcmp|strncpy|fgets"))
|
|
{
|
|
if (Token::Match(tok->next(), std::string("( " + varnames + " , %num% , %num% )").c_str()) ||
|
|
Token::Match(tok->next(), std::string("( %var% , " + varnames + " , %num% )").c_str()))
|
|
{
|
|
const char *num = tok->strAt(varc + 6);
|
|
if (std::atoi(num) > total_size)
|
|
{
|
|
bufferOverrun(tok);
|
|
}
|
|
}
|
|
continue;
|
|
}
|
|
|
|
|
|
// Loop..
|
|
if (Token::simpleMatch(tok, "for ("))
|
|
{
|
|
const Token *tok2 = tok->tokAt(2);
|
|
|
|
// for - setup..
|
|
if (Token::Match(tok2, "%var% = %any% ;"))
|
|
tok2 = tok2->tokAt(4);
|
|
else if (Token::Match(tok2, "%type% %var% = %any% ;"))
|
|
tok2 = tok2->tokAt(5);
|
|
else if (Token::Match(tok2, "%type% %type% %var% = %any% ;"))
|
|
tok2 = tok2->tokAt(6);
|
|
else
|
|
continue;
|
|
|
|
// for - condition..
|
|
if (!Token::Match(tok2, "%var% < %num% ;") && !Token::Match(tok2, "%var% <= %num% ;"))
|
|
continue;
|
|
|
|
// Get index variable and stopsize.
|
|
const char *strindex = tok2->str().c_str();
|
|
int value = ((tok2->strAt(1)[1] == '=') ? 1 : 0) + std::atoi(tok2->strAt(2));
|
|
if (value <= size)
|
|
continue;
|
|
|
|
// Goto the end of the for loop..
|
|
while (tok2 && tok2->str() != ")")
|
|
tok2 = tok2->next();
|
|
if (!tok2 || !tok2->tokAt(5))
|
|
break;
|
|
|
|
std::ostringstream pattern;
|
|
pattern << varnames << " [ " << strindex << " ]";
|
|
|
|
int indentlevel2 = 0;
|
|
while ((tok2 = tok2->next()))
|
|
{
|
|
if (tok2->str() == ";" && indentlevel2 == 0)
|
|
break;
|
|
|
|
if (tok2->str() == "{")
|
|
++indentlevel2;
|
|
|
|
if (tok2->str() == "}")
|
|
{
|
|
--indentlevel2;
|
|
if (indentlevel2 <= 0)
|
|
break;
|
|
}
|
|
|
|
if (Token::Match(tok2, pattern.str().c_str()))
|
|
{
|
|
bufferOverrun(tok2);
|
|
break;
|
|
}
|
|
|
|
}
|
|
continue;
|
|
}
|
|
|
|
|
|
// Writing data into array..
|
|
if (Token::Match(tok, ("strcpy|strcat ( " + varnames + " , %str% )").c_str()))
|
|
{
|
|
int len = 0;
|
|
const char *str = tok->strAt(varc + 4);
|
|
while (*str)
|
|
{
|
|
if (*str == '\\')
|
|
++str;
|
|
++str;
|
|
++len;
|
|
}
|
|
if (len > 2 && len >= (int)size + 2)
|
|
{
|
|
bufferOverrun(tok);
|
|
}
|
|
continue;
|
|
}
|
|
|
|
|
|
// Dangerous usage of strncat..
|
|
if (varid > 0 && Token::Match(tok, "strncat ( %varid% , %any% , %num% )", varid))
|
|
{
|
|
int n = atoi(tok->strAt(6));
|
|
if (n == size)
|
|
strncatUsage(tok);
|
|
}
|
|
|
|
|
|
// Dangerous usage of strncpy + strncat..
|
|
if (varid > 0 && Token::Match(tok, "strncpy|strncat ( %varid% , %any% , %num% ) ; strncat ( %varid% , %any% , %num% )", varid))
|
|
{
|
|
int n = atoi(tok->strAt(6)) + atoi(tok->strAt(15));
|
|
if (n > size)
|
|
strncatUsage(tok->tokAt(9));
|
|
}
|
|
|
|
|
|
// sprintf..
|
|
if (varid > 0 && Token::Match(tok, "sprintf ( %varid% , %str% ,", varid))
|
|
{
|
|
int len = 0;
|
|
for (const Token *tok2 = tok->tokAt(6); tok2 && tok2->str() != ")"; tok2 = tok2->next())
|
|
{
|
|
if (tok2->str()[0] == '\"')
|
|
{
|
|
len -= 2;
|
|
const char *str = tok->str().c_str();
|
|
while (*str)
|
|
{
|
|
if (*str == '\\')
|
|
++str;
|
|
++str;
|
|
++len;
|
|
}
|
|
}
|
|
}
|
|
if (len > (int)size)
|
|
{
|
|
bufferOverrun(tok);
|
|
}
|
|
}
|
|
|
|
// snprintf..
|
|
if (varid > 0 && Token::Match(tok, "snprintf ( %varid% , %num% ,", varid))
|
|
{
|
|
int n = std::atoi(tok->strAt(4));
|
|
if (n > size)
|
|
outOfBounds(tok->tokAt(4), "snprintf size");
|
|
}
|
|
|
|
// cin..
|
|
if (varid > 0 && Token::Match(tok, "cin >> %varid% ;", varid))
|
|
{
|
|
bufferOverrun(tok);
|
|
}
|
|
|
|
// Function call..
|
|
// It's not interesting to check what happens when the whole struct is
|
|
// sent as the parameter, that is checked separately anyway.
|
|
if (Token::Match(tok, "%var% ("))
|
|
{
|
|
// Don't make recursive checking..
|
|
if (std::find(_callStack.begin(), _callStack.end(), tok) != _callStack.end())
|
|
continue;
|
|
|
|
// Only perform this checking if showAll setting is enabled..
|
|
if (!_settings->_showAll)
|
|
continue;
|
|
|
|
unsigned int parlevel = 0, par = 0;
|
|
for (const Token *tok2 = tok; tok2; tok2 = tok2->next())
|
|
{
|
|
if (tok2->str() == "(")
|
|
{
|
|
++parlevel;
|
|
}
|
|
|
|
else if (tok2->str() == ")")
|
|
{
|
|
--parlevel;
|
|
if (parlevel < 1)
|
|
{
|
|
par = 0;
|
|
break;
|
|
}
|
|
}
|
|
|
|
else if (parlevel == 1 && (tok2->str() == ","))
|
|
{
|
|
++par;
|
|
}
|
|
|
|
if (parlevel == 1 && Token::Match(tok2, std::string("[(,] " + varnames + " [,)]").c_str()))
|
|
{
|
|
++par;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (par == 0)
|
|
continue;
|
|
|
|
// Find function..
|
|
const Token *ftok = _tokenizer->GetFunctionTokenByName(tok->str().c_str());
|
|
if (!ftok)
|
|
continue;
|
|
|
|
// Parse head of function..
|
|
ftok = ftok->tokAt(2);
|
|
parlevel = 1;
|
|
while (ftok && parlevel == 1 && par >= 1)
|
|
{
|
|
if (ftok->str() == "(")
|
|
++parlevel;
|
|
|
|
else if (ftok->str() == ")")
|
|
--parlevel;
|
|
|
|
else if (ftok->str() == ",")
|
|
--par;
|
|
|
|
else if (par == 1 && parlevel == 1 && Token::Match(ftok, "%var% [,)]"))
|
|
{
|
|
// Parameter name..
|
|
const char *parname[2];
|
|
parname[0] = ftok->str().c_str();
|
|
parname[1] = 0;
|
|
|
|
// Goto function body..
|
|
while (ftok && (ftok->str() != "{"))
|
|
ftok = ftok->next();
|
|
ftok = ftok ? ftok->next() : 0;
|
|
|
|
// Check variable usage in the function..
|
|
_callStack.push_back(tok);
|
|
CheckBufferOverrun_CheckScope(ftok, parname, size, total_size, 0);
|
|
_callStack.pop_back();
|
|
|
|
// break out..
|
|
break;
|
|
}
|
|
|
|
ftok = ftok->next();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Checking local variables in a scope
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckBufferOverrunClass::CheckBufferOverrun_GlobalAndLocalVariable()
|
|
{
|
|
int indentlevel = 0;
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
|
|
{
|
|
if (tok->str() == "{")
|
|
++indentlevel;
|
|
|
|
else if (tok->str() == "}")
|
|
--indentlevel;
|
|
|
|
const char *varname[2] = {0};
|
|
unsigned int size = 0;
|
|
const char *type = 0;
|
|
unsigned int varid = 0;
|
|
int nextTok = 0;
|
|
|
|
if (Token::Match(tok, "%type% %var% [ %num% ] [;=]"))
|
|
{
|
|
varname[0] = tok->strAt(1);
|
|
size = std::strtoul(tok->strAt(3), NULL, 10);
|
|
type = tok->str().c_str();
|
|
varid = tok->tokAt(1)->varId();
|
|
nextTok = 6;
|
|
}
|
|
else if (indentlevel > 0 && Token::Match(tok, "[*;{}] %var% = new %type% [ %num% ]"))
|
|
{
|
|
varname[0] = tok->strAt(1);
|
|
size = std::strtoul(tok->strAt(6), NULL, 10);
|
|
type = tok->strAt(4);
|
|
varid = tok->tokAt(1)->varId();
|
|
nextTok = 8;
|
|
}
|
|
else if (indentlevel > 0 && Token::Match(tok, "[*;{}] %var% = malloc ( %num% ) ;"))
|
|
{
|
|
varname[0] = tok->strAt(1);
|
|
size = std::strtoul(tok->strAt(5), NULL, 10);
|
|
type = "char";
|
|
varid = tok->tokAt(1)->varId();
|
|
nextTok = 7;
|
|
}
|
|
else
|
|
{
|
|
continue;
|
|
}
|
|
|
|
int total_size = size * _tokenizer->SizeOfType(type);
|
|
if (total_size == 0)
|
|
continue;
|
|
|
|
// The callstack is empty
|
|
_callStack.clear();
|
|
CheckBufferOverrun_CheckScope(tok->tokAt(nextTok), varname, size, total_size, varid);
|
|
}
|
|
}
|
|
//---------------------------------------------------------------------------
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Checking member variables of structs..
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckBufferOverrunClass::CheckBufferOverrun_StructVariable()
|
|
{
|
|
const char declstruct[] = "struct|class %var% {";
|
|
for (const Token *tok = Token::findmatch(_tokenizer->tokens(), declstruct);
|
|
tok; tok = Token::findmatch(tok->next(), declstruct))
|
|
{
|
|
const std::string &structname = tok->next()->str();
|
|
|
|
// Found a struct declaration. Search for arrays..
|
|
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next())
|
|
{
|
|
if (tok2->str() == "}")
|
|
break;
|
|
|
|
int ivar = 0;
|
|
if (Token::Match(tok2->next(), "%type% %var% [ %num% ] ;"))
|
|
ivar = 2;
|
|
else if (Token::Match(tok2->next(), "%type% %type% %var% [ %num% ] ;"))
|
|
ivar = 3;
|
|
else if (Token::Match(tok2->next(), "%type% * %var% [ %num% ] ;"))
|
|
ivar = 3;
|
|
else if (Token::Match(tok2->next(), "%type% %type% * %var% [ %num% ] ;"))
|
|
ivar = 4;
|
|
else
|
|
continue;
|
|
|
|
const char *varname[3] = {0, 0, 0};
|
|
varname[1] = tok2->strAt(ivar);
|
|
int arrsize = std::atoi(tok2->strAt(ivar + 2));
|
|
int total_size = arrsize * _tokenizer->SizeOfType(tok2->strAt(1));
|
|
if (total_size == 0)
|
|
continue;
|
|
|
|
|
|
// Class member variable => Check functions
|
|
if (tok->str() == "class")
|
|
{
|
|
std::string func_pattern(structname + " :: %var% (");
|
|
const Token *tok3 = Token::findmatch(_tokenizer->tokens(), func_pattern.c_str());
|
|
while (tok3)
|
|
{
|
|
for (const Token *tok4 = tok3; tok4; tok4 = tok4->next())
|
|
{
|
|
if (Token::Match(tok4, "[;{}]"))
|
|
break;
|
|
|
|
if (Token::simpleMatch(tok4, ") {"))
|
|
{
|
|
const char *names[2] = {varname[1], 0};
|
|
CheckBufferOverrun_CheckScope(tok4->tokAt(2), names, arrsize, total_size, 0);
|
|
break;
|
|
}
|
|
}
|
|
tok3 = Token::findmatch(tok3->next(), func_pattern.c_str());
|
|
}
|
|
}
|
|
|
|
for (const Token *tok3 = _tokenizer->tokens(); tok3; tok3 = tok3->next())
|
|
{
|
|
if (tok3->str() != structname)
|
|
continue;
|
|
|
|
// Declare variable: Fred fred1;
|
|
if (Token::Match(tok3->next(), "%var% ;"))
|
|
varname[0] = tok3->strAt(1);
|
|
|
|
// Declare pointer: Fred *fred1
|
|
else if (Token::Match(tok3->next(), "* %var% [,);=]"))
|
|
varname[0] = tok3->strAt(2);
|
|
|
|
else
|
|
continue;
|
|
|
|
|
|
// Goto end of statement.
|
|
const Token *CheckTok = NULL;
|
|
while (tok3)
|
|
{
|
|
// End of statement.
|
|
if (tok3->str() == ";")
|
|
{
|
|
CheckTok = tok3;
|
|
break;
|
|
}
|
|
|
|
// End of function declaration..
|
|
if (Token::simpleMatch(tok3, ") ;"))
|
|
break;
|
|
|
|
// Function implementation..
|
|
if (Token::simpleMatch(tok3, ") {"))
|
|
{
|
|
CheckTok = tok3->tokAt(2);
|
|
break;
|
|
}
|
|
|
|
tok3 = tok3->next();
|
|
}
|
|
|
|
if (!tok3)
|
|
break;
|
|
|
|
if (!CheckTok)
|
|
continue;
|
|
|
|
// Check variable usage..
|
|
CheckBufferOverrun_CheckScope(CheckTok, varname, arrsize, total_size, 0);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckBufferOverrunClass::bufferOverrun()
|
|
{
|
|
CheckBufferOverrun_GlobalAndLocalVariable();
|
|
CheckBufferOverrun_StructVariable();
|
|
}
|
|
//---------------------------------------------------------------------------
|
|
|
|
|
|
|
|
|
|
|