572 lines
18 KiB
C++
572 lines
18 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2009 Daniel Marjamäki, Reijo Tomperi, Nicolas Le Cam,
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* Leandro Penz, Kimmo Varis
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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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// Buffer overrun..
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//---------------------------------------------------------------------------
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#include "checkbufferoverrun.h"
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#include <algorithm>
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#include <sstream>
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#include <list>
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#include <cstring>
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#include <cstdlib> // <- strtoul
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//---------------------------------------------------------------------------
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// _callStack used when parsing into subfunctions.
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CheckBufferOverrunClass::CheckBufferOverrunClass(const Tokenizer *tokenizer, const Settings &settings, ErrorLogger *errorLogger)
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: _settings(settings)
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{
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_tokenizer = tokenizer;
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_errorLogger = errorLogger;
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}
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CheckBufferOverrunClass::~CheckBufferOverrunClass()
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{
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}
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void CheckBufferOverrunClass::arrayIndexOutOfBounds(const Token *tok)
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{
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_callStack.push_back(tok);
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_errorLogger->arrayIndexOutOfBounds(_tokenizer, _callStack);
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_callStack.pop_back();
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}
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//---------------------------------------------------------------------------
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//---------------------------------------------------------------------------
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// Check array usage..
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//---------------------------------------------------------------------------
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void CheckBufferOverrunClass::CheckBufferOverrun_CheckScope(const Token *tok, const char *varname[], const int size, const int total_size, unsigned int varid)
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{
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unsigned int varc = 0;
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std::string varnames;
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while (varname[varc])
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{
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if (varc > 0)
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varnames += " . ";
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varnames += varname[varc];
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++varc;
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}
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if (varc == 0)
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varc = 1;
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varc = 2 * (varc - 1);
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// Array index..
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if (varid > 0)
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{
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if (Token::Match(tok, "%varid% [ %num% ]", varid))
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{
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const char *num = tok->strAt(2);
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if (std::strtol(num, NULL, 10) >= size)
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{
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arrayIndexOutOfBounds(tok->next());
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}
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}
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}
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else if (Token::Match(tok, std::string(varnames + " [ %num% ]").c_str()))
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{
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const char *num = tok->strAt(2 + varc);
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if (std::strtol(num, NULL, 10) >= size)
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{
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arrayIndexOutOfBounds(tok->next());
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}
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}
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int indentlevel = 0;
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for (; tok; tok = tok->next())
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{
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if (tok->str() == "{")
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{
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++indentlevel;
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}
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else if (tok->str() == "}")
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{
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--indentlevel;
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if (indentlevel < 0)
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return;
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}
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// Array index..
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if (varid > 0)
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{
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if (!tok->isName() && !Token::Match(tok, "[.&]") && Token::Match(tok->next(), "%varid% [ %num% ]", varid))
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{
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const char *num = tok->strAt(3);
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if (std::strtol(num, NULL, 10) >= size)
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{
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arrayIndexOutOfBounds(tok->next());
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}
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}
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}
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else if (!tok->isName() && !Token::Match(tok, "[.&]") && Token::Match(tok->next(), std::string(varnames + " [ %num% ]").c_str()))
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{
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const char *num = tok->next()->strAt(2 + varc);
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if (std::strtol(num, NULL, 10) >= size)
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{
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arrayIndexOutOfBounds(tok->next());
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}
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tok = tok->tokAt(4);
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continue;
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}
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// memset, memcmp, memcpy, strncpy, fgets..
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if (varid > 0)
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{
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if (Token::Match(tok, "memset|memcpy|memmove|memcmp|strncpy|fgets"))
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{
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if (Token::Match(tok->next(), "( %varid% , %num% , %num% )", varid) ||
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Token::Match(tok->next(), "( %var% , %varid% , %num% )", varid))
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{
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const char *num = tok->strAt(6);
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if (std::atoi(num) > total_size)
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{
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_errorLogger->bufferOverrun(_tokenizer, tok);
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}
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}
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continue;
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}
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}
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else if (Token::Match(tok, "memset|memcpy|memmove|memcmp|strncpy|fgets"))
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{
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if (Token::Match(tok->next(), std::string("( " + varnames + " , %num% , %num% )").c_str()) ||
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Token::Match(tok->next(), std::string("( %var% , " + varnames + " , %num% )").c_str()))
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{
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const char *num = tok->strAt(varc + 6);
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if (std::atoi(num) > total_size)
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{
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_errorLogger->bufferOverrun(_tokenizer, tok);
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}
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}
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continue;
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}
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// Loop..
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if (Token::simpleMatch(tok, "for ("))
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{
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const Token *tok2 = tok->tokAt(2);
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// for - setup..
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if (Token::Match(tok2, "%var% = 0 ;"))
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tok2 = tok2->tokAt(4);
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else if (Token::Match(tok2, "%type% %var% = 0 ;"))
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tok2 = tok2->tokAt(5);
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else if (Token::Match(tok2, "%type% %type% %var% = 0 ;"))
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tok2 = tok2->tokAt(6);
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else
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continue;
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// for - condition..
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if (!Token::Match(tok2, "%var% < %num% ;") && !Token::Match(tok2, "%var% <= %num% ;"))
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continue;
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// Get index variable and stopsize.
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const char *strindex = tok2->aaaa();
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int value = ((tok2->next()->aaaa1() == '=') ? 1 : 0) + std::atoi(tok2->strAt(2));
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if (value <= size)
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continue;
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// Goto the end of the for loop..
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while (tok2 && tok2->str() != ")")
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tok2 = tok2->next();
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if (!tok2 || !tok2->tokAt(5))
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break;
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std::ostringstream pattern;
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pattern << varnames << " [ " << strindex << " ]";
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int indentlevel2 = 0;
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while ((tok2 = tok2->next()))
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{
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if (tok2->str() == ";" && indentlevel2 == 0)
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break;
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if (tok2->str() == "{")
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++indentlevel2;
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if (tok2->str() == "}")
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{
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--indentlevel2;
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if (indentlevel2 <= 0)
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break;
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}
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if (Token::Match(tok2, pattern.str().c_str()))
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{
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_errorLogger->bufferOverrun(_tokenizer, tok2);
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break;
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}
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}
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continue;
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}
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// Writing data into array..
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if (Token::Match(tok, std::string("strcpy ( " + varnames + " , %str% )").c_str()))
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{
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int len = 0;
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const char *str = tok->strAt(varc + 4);
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while (*str)
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{
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if (*str == '\\')
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++str;
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++str;
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++len;
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}
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if (len > 2 && len >= (int)size + 2)
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{
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_errorLogger->bufferOverrun(_tokenizer, tok);
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}
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continue;
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}
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// sprintf..
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if (varid > 0 && Token::Match(tok, "sprintf ( %varid% , %str% ,", varid))
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{
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int len = 0;
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for (const Token *tok2 = tok->tokAt(6); tok2 && tok2->str() != ")"; tok2 = tok2->next())
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{
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if (tok2->aaaa0() == '\"')
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{
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len -= 2;
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const char *str = tok->strAt(0);
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while (*str)
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{
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if (*str == '\\')
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++str;
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++str;
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++len;
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}
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}
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}
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if (len > (int)size)
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{
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_errorLogger->bufferOverrun(_tokenizer, tok);
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}
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}
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// snprintf..
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if (varid > 0 && Token::Match(tok, "snprintf ( %varid% , %num%", varid))
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{
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int n = std::atoi(tok->strAt(4));
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if (n > size)
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_errorLogger->outOfBounds(_tokenizer, tok->tokAt(4), "snprintf size");
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}
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// Function call..
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// It's not interesting to check what happens when the whole struct is
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// sent as the parameter, that is checked separately anyway.
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if (Token::Match(tok, "%var% ("))
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{
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// Don't make recursive checking..
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if (std::find(_callStack.begin(), _callStack.end(), tok) != _callStack.end())
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continue;
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// Only perform this checking if showAll setting is enabled..
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if (!_settings._showAll)
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continue;
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unsigned int parlevel = 0, par = 0;
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for (const Token *tok2 = tok; tok2; tok2 = tok2->next())
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{
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if (tok2->str() == "(")
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{
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++parlevel;
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}
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else if (tok2->str() == ")")
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{
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--parlevel;
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if (parlevel < 1)
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{
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par = 0;
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break;
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}
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}
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else if (parlevel == 1 && (tok2->str() == ","))
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{
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++par;
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}
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if (parlevel == 1 && Token::Match(tok2, std::string("[(,] " + varnames + " [,)]").c_str()))
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{
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++par;
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break;
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}
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}
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if (par == 0)
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continue;
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// Find function..
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const Token *ftok = _tokenizer->GetFunctionTokenByName(tok->aaaa());
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if (!ftok)
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continue;
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// Parse head of function..
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ftok = ftok->tokAt(2);
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parlevel = 1;
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while (ftok && parlevel == 1 && par >= 1)
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{
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if (ftok->str() == "(")
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++parlevel;
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else if (ftok->str() == ")")
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--parlevel;
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else if (ftok->str() == ",")
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--par;
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else if (par == 1 && parlevel == 1 && Token::Match(ftok, "%var% [,)]"))
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{
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// Parameter name..
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const char *parname[2];
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parname[0] = ftok->aaaa();
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parname[1] = 0;
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// Goto function body..
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while (ftok && (ftok->str() != "{"))
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ftok = ftok->next();
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ftok = ftok ? ftok->next() : 0;
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// Check variable usage in the function..
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_callStack.push_back(tok);
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CheckBufferOverrun_CheckScope(ftok, parname, size, total_size, 0);
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_callStack.pop_back();
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// break out..
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break;
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}
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ftok = ftok->next();
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}
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}
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}
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}
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//---------------------------------------------------------------------------
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// Checking local variables in a scope
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//---------------------------------------------------------------------------
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void CheckBufferOverrunClass::CheckBufferOverrun_LocalVariable()
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{
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int indentlevel = 0;
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for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
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{
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if (tok->str() == "{")
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++indentlevel;
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else if (tok->str() == "}")
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--indentlevel;
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else if (indentlevel > 0)
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{
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const char *varname[2] = {0};
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unsigned int size = 0;
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const char *type = 0;
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unsigned int varid = 0;
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int nextTok = 0;
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if (Token::Match(tok, "%type% %var% [ %num% ] ;"))
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{
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varname[0] = tok->strAt(1);
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size = std::strtoul(tok->strAt(3), NULL, 10);
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type = tok->aaaa();
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varid = tok->tokAt(1)->varId();
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nextTok = 6;
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}
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else if (Token::Match(tok, "[*;{}] %var% = new %type% [ %num% ]"))
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{
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varname[0] = tok->strAt(1);
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size = std::strtoul(tok->strAt(6), NULL, 10);
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type = tok->strAt(4);
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varid = tok->tokAt(1)->varId();
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nextTok = 8;
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}
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else
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{
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continue;
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}
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int total_size = size * _tokenizer->SizeOfType(type);
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if (total_size == 0)
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continue;
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// The callstack is empty
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_callStack.clear();
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CheckBufferOverrun_CheckScope(tok->tokAt(nextTok), varname, size, total_size, varid);
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}
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}
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}
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//---------------------------------------------------------------------------
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//---------------------------------------------------------------------------
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// Checking member variables of structs..
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//---------------------------------------------------------------------------
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void CheckBufferOverrunClass::CheckBufferOverrun_StructVariable()
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{
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const char declstruct[] = "struct|class %var% {";
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for (const Token *tok = Token::findmatch(_tokenizer->tokens(), declstruct);
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tok; tok = Token::findmatch(tok->next(), declstruct))
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{
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const std::string &structname = tok->next()->str();
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// Found a struct declaration. Search for arrays..
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for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next())
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{
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if (tok2->str() == "}")
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break;
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int ivar = 0;
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if (Token::Match(tok2->next(), "%type% %var% [ %num% ] ;"))
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ivar = 2;
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else if (Token::Match(tok2->next(), "%type% %type% %var% [ %num% ] ;"))
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ivar = 3;
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else if (Token::Match(tok2->next(), "%type% * %var% [ %num% ] ;"))
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ivar = 3;
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else if (Token::Match(tok2->next(), "%type% %type% * %var% [ %num% ] ;"))
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ivar = 4;
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else
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continue;
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const char *varname[3] = {0, 0, 0};
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varname[1] = tok2->strAt(ivar);
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int arrsize = std::atoi(tok2->strAt(ivar + 2));
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int total_size = arrsize * _tokenizer->SizeOfType(tok2->next()->aaaa());
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if (total_size == 0)
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continue;
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// Class member variable => Check functions
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if (tok->str() == "class")
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{
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std::string func_pattern(structname + " :: %var% (");
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const Token *tok3 = Token::findmatch(_tokenizer->tokens(), func_pattern.c_str());
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while (tok3)
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{
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for (const Token *tok4 = tok3; tok4; tok4 = tok4->next())
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{
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if (Token::Match(tok4, "[;{}]"))
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break;
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if (Token::simpleMatch(tok4, ") {"))
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{
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const char *names[2] = {varname[1], 0};
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CheckBufferOverrun_CheckScope(tok4->tokAt(2), names, arrsize, total_size, 0);
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break;
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}
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}
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tok3 = Token::findmatch(tok3->next(), func_pattern.c_str());
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}
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}
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for (const Token *tok3 = _tokenizer->tokens(); tok3; tok3 = tok3->next())
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{
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if (tok3->str() != structname)
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continue;
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// Declare variable: Fred fred1;
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if (Token::Match(tok3->next(), "%var% ;"))
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varname[0] = tok3->strAt(1);
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// Declare pointer: Fred *fred1
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else if (Token::Match(tok3->next(), "* %var% [,);=]"))
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varname[0] = tok3->strAt(2);
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else
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continue;
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// Goto end of statement.
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const Token *CheckTok = NULL;
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while (tok3)
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{
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// End of statement.
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if (tok3->str() == ";")
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{
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CheckTok = tok3;
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break;
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}
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// End of function declaration..
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if (Token::simpleMatch(tok3, ") ;"))
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break;
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// Function implementation..
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if (Token::simpleMatch(tok3, ") {"))
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{
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CheckTok = tok3->tokAt(2);
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break;
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}
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tok3 = tok3->next();
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}
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if (!tok3)
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break;
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if (!CheckTok)
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continue;
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// Check variable usage..
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CheckBufferOverrun_CheckScope(CheckTok, varname, arrsize, total_size, 0);
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}
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}
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}
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}
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//---------------------------------------------------------------------------
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void CheckBufferOverrunClass::bufferOverrun()
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{
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CheckBufferOverrun_LocalVariable();
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CheckBufferOverrun_StructVariable();
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}
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//---------------------------------------------------------------------------
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