1437 lines
48 KiB
C++
1437 lines
48 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 and 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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// Buffer overrun..
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//---------------------------------------------------------------------------
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#include "checkbufferoverrun.h"
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#include "tokenize.h"
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#include "errorlogger.h"
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#include "mathlib.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 <cctype>
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#include <climits>
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#include <cassert> // <- assert
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#include <cstdlib> // <- strtoul
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//---------------------------------------------------------------------------
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// Register this check class (by creating a static instance of it)
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namespace
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{
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CheckBufferOverrun instance;
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}
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//---------------------------------------------------------------------------
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void CheckBufferOverrun::arrayIndexOutOfBounds(const Token *tok, int size, int index)
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{
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if (!tok)
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arrayIndexOutOfBounds(size, index);
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else
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{
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_callStack.push_back(tok);
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arrayIndexOutOfBounds(size, index);
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_callStack.pop_back();
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}
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}
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void CheckBufferOverrun::arrayIndexOutOfBounds(int size, int index)
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{
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Severity::e severity;
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if (size <= 1 || _callStack.size() > 1)
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{
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severity = Severity::possibleError;
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if (_settings->inconclusive == false)
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return;
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}
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else
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{
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severity = Severity::error;
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}
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if (_callStack.size() == 1)
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{
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std::ostringstream oss;
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oss << "Array '" << (*_callStack.begin())->str() << "[" << size << "]' index " << index << " out of bounds";
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reportError(_callStack, severity, "arrayIndexOutOfBounds", oss.str().c_str());
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}
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else
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reportError(_callStack, severity, "arrayIndexOutOfBounds", "Array index out of bounds");
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}
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void CheckBufferOverrun::bufferOverrun(const Token *tok, const std::string &varnames)
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{
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Severity::e severity;
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if (_callStack.size() > 0)
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{
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severity = Severity::possibleError;
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if (_settings->inconclusive == false)
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return;
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}
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else
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{
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severity = Severity::error;
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}
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std::string v = varnames;
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while (v.find(" ") != std::string::npos)
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v.erase(v.find(" "), 1);
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std::string errmsg("Buffer access out-of-bounds");
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if (!v.empty())
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errmsg += ": " + v;
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reportError(tok, severity, "bufferAccessOutOfBounds", errmsg);
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}
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void CheckBufferOverrun::dangerousStdCin(const Token *tok)
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{
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if (_settings && _settings->inconclusive == false)
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return;
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reportError(tok, Severity::possibleError, "dangerousStdCin", "Dangerous usage of std::cin, possible buffer overrun");
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}
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void CheckBufferOverrun::strncatUsage(const Token *tok)
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{
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if (_settings && _settings->inconclusive == false)
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return;
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reportError(tok, Severity::possibleError, "strncatUsage", "Dangerous usage of strncat. Tip: the 3rd parameter means maximum number of characters to append");
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}
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void CheckBufferOverrun::outOfBounds(const Token *tok, const std::string &what)
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{
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reportError(tok, Severity::error, "outOfBounds", what + " is out of bounds");
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}
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void CheckBufferOverrun::sizeArgumentAsChar(const Token *tok)
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{
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if (_settings && _settings->inconclusive == false)
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return;
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reportError(tok, Severity::possibleError, "sizeArgumentAsChar", "The size argument is given as a char constant");
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}
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void CheckBufferOverrun::terminateStrncpyError(const Token *tok)
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{
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reportError(tok, Severity::style, "terminateStrncpy", "After a strncpy() the buffer should be zero-terminated");
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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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/**
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* @brief This is a helper class to be used with std::find_if
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*/
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class TokenStrEquals
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{
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public:
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/**
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* @param str Token::str() is compared against this.
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*/
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TokenStrEquals(const std::string &str)
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: value(str)
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{
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}
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/**
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* Called automatically by std::find_if
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* @param tok Token inside the list
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*/
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bool operator()(const Token *tok) const
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{
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return value == tok->str();
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}
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private:
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const std::string value;
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};
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void CheckBufferOverrun::checkScope(const Token *tok, const std::vector<std::string> &varname, const int size, const int total_size, unsigned int varid)
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{
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std::string varnames;
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for (unsigned int i = 0; i < varname.size(); ++i)
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varnames += (i == 0 ? "" : " . ") + varname[i];
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const unsigned int varc(varname.empty() ? 0 : (varname.size() - 1) * 2);
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if (Token::Match(tok, "return"))
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{
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tok = tok->next();
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if (!tok)
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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 (Token::Match(tok, "%varid% [ %num% ]", varid))
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{
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int index = MathLib::toLongNumber(tok->strAt(2));
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if (index < 0 || index >= size)
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{
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arrayIndexOutOfBounds(tok, size, index);
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}
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}
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}
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else if (Token::Match(tok, (varnames + " [ %num% ]").c_str()))
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{
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int index = MathLib::toLongNumber(tok->strAt(2 + varc));
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if (index < 0 || index >= size)
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{
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arrayIndexOutOfBounds(tok->tokAt(varc), size, index);
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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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if (varid != 0 && Token::Match(tok, "%varid% = new|malloc|realloc", varid))
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{
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// Abort
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break;
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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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int index = MathLib::toLongNumber(tok->strAt(3));
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if (index < 0 || index >= size)
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{
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if (index > size || !Token::Match(tok->previous(), "& ("))
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{
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arrayIndexOutOfBounds(tok->next(), size, index);
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}
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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(), (varnames + " [ %num% ]").c_str()))
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{
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int index = MathLib::toLongNumber(tok->strAt(3 + varc));
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if (index < 0 || index >= size)
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{
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arrayIndexOutOfBounds(tok->tokAt(1 + varc), size, index);
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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 (_settings->_checkCodingStyle)
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{
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// check for strncpy which is not terminated
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if (Token::Match(tok, "strncpy ( %varid% , %any% , %num% )", varid))
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{
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// strncpy takes entire variable length as input size
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if (MathLib::toLongNumber(tok->strAt(6)) == total_size)
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{
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const Token *tok2 = tok->next()->link()->next();
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for (; tok2; tok2 = tok2->next())
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{
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if (tok2->varId() == tok->tokAt(2)->varId())
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{
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if (!Token::Match(tok2, "%varid% [ %any% ] = 0 ;", tok->tokAt(2)->varId()))
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{
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terminateStrncpyError(tok);
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}
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break;
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}
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}
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}
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}
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}
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if (Token::Match(tok, "memset|memcpy|memmove|memcmp|strncpy|fgets ( %varid% , %any% , %any% )", varid) ||
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Token::Match(tok, "memset|memcpy|memmove|memcmp|fgets ( %var% , %varid% , %any% )", varid))
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{
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const Token *tokSz = tok->tokAt(6);
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if (tokSz->str()[0] == '\'')
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sizeArgumentAsChar(tok);
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else if (tokSz->isNumber())
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{
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const std::string num = tok->strAt(6);
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if (MathLib::toLongNumber(num) < 0 || MathLib::toLongNumber(num) > total_size)
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{
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bufferOverrun(tok, varnames);
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}
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}
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}
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}
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else if (Token::Match(tok, ("memset|memcpy|memmove|memcmp|strncpy|fgets ( " + varnames + " , %num% , %num% )").c_str()) ||
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Token::Match(tok, ("memcpy|memcmp ( %var% , " + varnames + " , %num% )").c_str()))
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{
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const std::string num = tok->strAt(varc + 6);
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if (MathLib::toLongNumber(num) < 0 || MathLib::toLongNumber(num) > total_size)
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{
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bufferOverrun(tok, varnames);
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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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unsigned int counter_varid = 0;
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std::string min_counter_value;
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std::string max_counter_value;
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// for - setup..
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if (Token::Match(tok2, "%var% = %any% ;"))
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{
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if (tok2->tokAt(2)->isNumber())
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{
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min_counter_value = tok2->strAt(2);
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}
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counter_varid = tok2->varId();
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tok2 = tok2->tokAt(4);
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}
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else if (Token::Match(tok2, "%type% %var% = %any% ;"))
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{
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if (tok2->tokAt(3)->isNumber())
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{
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min_counter_value = tok2->strAt(3);
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}
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counter_varid = tok2->next()->varId();
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tok2 = tok2->tokAt(5);
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}
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else if (Token::Match(tok2, "%type% %type% %var% = %any% ;"))
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{
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if (tok->tokAt(4)->isNumber())
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{
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min_counter_value = tok2->strAt(4);
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}
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counter_varid = tok2->tokAt(2)->varId();
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tok2 = tok2->tokAt(6);
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}
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else
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continue;
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if (counter_varid == 0)
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continue;
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bool maxMinFlipped = false;
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const Token *strindextoken = 0;
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if (Token::Match(tok2, "%varid% < %num% ;", counter_varid))
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{
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long value = MathLib::toLongNumber(tok2->strAt(2));
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max_counter_value = MathLib::toString<long>(value - 1);
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strindextoken = tok2;
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}
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else if (Token::Match(tok2, "%varid% <= %num% ;", counter_varid))
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{
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max_counter_value = tok2->strAt(2);
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strindextoken = tok2;
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}
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else if (Token::Match(tok2, " %num% < %varid% ;", counter_varid))
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{
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long value = MathLib::toLongNumber(tok2->str());
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maxMinFlipped = true;
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max_counter_value = min_counter_value;
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min_counter_value = MathLib::toString<long>(value + 1);
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strindextoken = tok2->tokAt(2);
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}
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else if (Token::Match(tok2, "%num% <= %varid% ;", counter_varid))
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{
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maxMinFlipped = true;
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max_counter_value = min_counter_value;
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min_counter_value = tok2->str();
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strindextoken = tok2->tokAt(2);
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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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// Get index variable and stopsize.
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const std::string strindex = strindextoken->str();
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bool condition_out_of_bounds = true;
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if (MathLib::toLongNumber(max_counter_value) < size)
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condition_out_of_bounds = false;
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const Token *tok3 = tok2->tokAt(4);
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assert(tok3 != NULL);
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if (Token::Match(tok3, "%varid% += %num% )", counter_varid) ||
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Token::Match(tok3, "%varid% = %num% + %varid% )", counter_varid))
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{
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if (!MathLib::isInt(tok3->strAt(2)))
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continue;
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const int num = MathLib::toLongNumber(tok3->strAt(2));
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// We have for example code: "for(i=2;i<22;i+=6)
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// We can calculate that max value for i is 20, not 21
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// 21-2 = 19
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// 19/6 = 3
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// 6*3+2 = 20
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long max = MathLib::toLongNumber(max_counter_value);
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long min = MathLib::toLongNumber(min_counter_value);
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max = ((max - min) / num) * num + min;
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max_counter_value = MathLib::toString<long>(max);
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if (max <= size)
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condition_out_of_bounds = false;
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}
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else if (Token::Match(tok3, "%varid% = %varid% + %num% )", counter_varid))
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{
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if (!MathLib::isInt(tok3->strAt(4)))
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continue;
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const int num = MathLib::toLongNumber(tok3->strAt(4));
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long max = MathLib::toLongNumber(max_counter_value);
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long min = MathLib::toLongNumber(min_counter_value);
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max = ((max - min) / num) * num + min;
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max_counter_value = MathLib::toString<long>(max);
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if (max <= size)
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condition_out_of_bounds = false;
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}
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else if (Token::Match(tok3, "%varid% -= %num% )", counter_varid) ||
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Token::Match(tok3, "%varid% = %num% - %varid% )", counter_varid))
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{
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if (!MathLib::isInt(tok3->strAt(2)))
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continue;
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const int num = MathLib::toLongNumber(tok3->strAt(2));
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long max = MathLib::toLongNumber(max_counter_value);
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long min = MathLib::toLongNumber(min_counter_value);
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max = ((max - min) / num) * num + min;
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max_counter_value = MathLib::toString<long>(max);
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if (max <= size)
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condition_out_of_bounds = false;
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}
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else if (Token::Match(tok3, "%varid% = %varid% - %num% )", counter_varid))
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{
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if (!MathLib::isInt(tok3->strAt(4)))
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continue;
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const int num = MathLib::toLongNumber(tok3->strAt(4));
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long max = MathLib::toLongNumber(max_counter_value);
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long min = MathLib::toLongNumber(min_counter_value);
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max = ((max - min) / num) * num + min;
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max_counter_value = MathLib::toString<long>(max);
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if (max <= size)
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condition_out_of_bounds = false;
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}
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else if (Token::Match(tok3, "--| %varid% --| )", counter_varid))
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{
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if (!maxMinFlipped && MathLib::toLongNumber(min_counter_value) < MathLib::toLongNumber(max_counter_value))
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{
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// Code relies on the fact that integer will overflow:
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// for (unsigned int i = 3; i < 5; --i)
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// Set min value in this case to zero.
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max_counter_value = min_counter_value;
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min_counter_value = "0";
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}
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}
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else if (! Token::Match(tok3, "++| %varid% ++| )", counter_varid))
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{
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continue;
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}
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// Goto the end paranthesis of the for-statement: "for (x; y; z)" ..
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tok2 = tok->next()->link();
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if (!tok2 || !tok2->tokAt(5))
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break;
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// Check is the counter variable increased elsewhere inside the loop or used
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// for anything else except reading
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bool bailOut = false;
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for (Token *loopTok = tok2->next(); loopTok && loopTok != tok2->next()->link(); loopTok = loopTok->next())
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{
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if (loopTok->varId() == counter_varid)
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{
|
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// Counter variable used inside loop
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if (Token::Match(loopTok->next(), "+=|-=|++|--|=") ||
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Token::Match(loopTok->previous(), "++|--"))
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{
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bailOut = true;
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break;
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}
|
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}
|
|
}
|
|
|
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if (bailOut)
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{
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break;
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}
|
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|
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std::ostringstream pattern;
|
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if (varid > 0)
|
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pattern << "%varid% [ " << strindex << " ]";
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else
|
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pattern << varnames << " [ " << strindex << " ]";
|
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|
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int indentlevel2 = 0;
|
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while ((tok2 = tok2->next()) != 0)
|
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{
|
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if (tok2->str() == ";" && indentlevel2 == 0)
|
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break;
|
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|
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if (tok2->str() == "{")
|
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++indentlevel2;
|
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|
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if (tok2->str() == "}")
|
|
{
|
|
--indentlevel2;
|
|
if (indentlevel2 <= 0)
|
|
break;
|
|
}
|
|
|
|
if (Token::Match(tok2, "if|switch"))
|
|
{
|
|
// Bailout
|
|
break;
|
|
}
|
|
|
|
if (condition_out_of_bounds && Token::Match(tok2, pattern.str().c_str(), varid))
|
|
{
|
|
bufferOverrun(tok2, varid > 0 ? "" : varnames.c_str());
|
|
break;
|
|
}
|
|
|
|
else if (varid > 0 && counter_varid > 0 && !min_counter_value.empty() && !max_counter_value.empty())
|
|
{
|
|
int min_index = 0;
|
|
int max_index = 0;
|
|
|
|
if (Token::Match(tok2, "%varid% [ %var% +|-|*|/ %num% ]", varid) &&
|
|
tok2->tokAt(2)->varId() == counter_varid)
|
|
{
|
|
const char action = tok2->strAt(3)[0];
|
|
const std::string &second(tok2->tokAt(4)->str());
|
|
|
|
//printf("min_index: %s %c %s\n", min_counter_value.c_str(), action, second.c_str());
|
|
//printf("max_index: %s %c %s\n", max_counter_value.c_str(), action, second.c_str());
|
|
|
|
min_index = std::atoi(MathLib::calculate(min_counter_value, second, action).c_str());
|
|
max_index = std::atoi(MathLib::calculate(max_counter_value, second, action).c_str());
|
|
}
|
|
else if (Token::Match(tok2, "%varid% [ %num% +|-|*|/ %var% ]", varid) &&
|
|
tok2->tokAt(4)->varId() == counter_varid)
|
|
{
|
|
const char action = tok2->strAt(3)[0];
|
|
const std::string &first(tok2->tokAt(2)->str());
|
|
|
|
//printf("min_index: %s %c %s\n", first.c_str(), action, min_counter_value.c_str());
|
|
//printf("max_index: %s %c %s\n", first.c_str(), action, max_counter_value.c_str());
|
|
|
|
min_index = std::atoi(MathLib::calculate(first, min_counter_value, action).c_str());
|
|
max_index = std::atoi(MathLib::calculate(first, max_counter_value, action).c_str());
|
|
}
|
|
|
|
//printf("min_index = %d, max_index = %d, size = %d\n", min_index, max_index, size);
|
|
if (min_index >= size || max_index >= size)
|
|
{
|
|
arrayIndexOutOfBounds(tok2, size, min_index > max_index ? min_index : max_index);
|
|
}
|
|
}
|
|
|
|
}
|
|
continue;
|
|
}
|
|
|
|
|
|
// Writing data into array..
|
|
if ((varid > 0 && Token::Match(tok, "strcpy|strcat ( %varid% , %str% )", varid)) ||
|
|
(varid == 0 && Token::Match(tok, ("strcpy|strcat ( " + varnames + " , %str% )").c_str())))
|
|
{
|
|
long len = Token::getStrLength(tok->tokAt(varc + 4));
|
|
if (len < 0 || len >= total_size)
|
|
{
|
|
bufferOverrun(tok, varid > 0 ? "" : varnames.c_str());
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Writing data into array..
|
|
if (varid > 0 &&
|
|
Token::Match(tok, "read|write ( %any% , %varid% , %num% )", varid) &&
|
|
MathLib::isInt(tok->strAt(6)))
|
|
{
|
|
long len = MathLib::toLongNumber(tok->strAt(6));
|
|
if (len < 0 || len > total_size)
|
|
{
|
|
bufferOverrun(tok);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// fread|frwite
|
|
// size_t fread ( void * ptr, size_t size, size_t count, FILE * stream );
|
|
// ptr -> Pointer to a block of memory with a minimum size of (size*count) bytes.
|
|
// size -> Size in bytes of each element to be read.
|
|
// count -> Number of elements, each one with a size of size bytes.
|
|
// stream -> Pointer to a FILE object that specifies an input stream.
|
|
if (varid > 0 &&
|
|
Token::Match(tok, "fread|fwrite ( %varid% , %num% , %num% , %any% )", varid) &&
|
|
MathLib::isInt(tok->strAt(6)))
|
|
{
|
|
long len = MathLib::toLongNumber(tok->strAt(4)) * MathLib::toLongNumber(tok->strAt(6));
|
|
if (len < 0 || len > total_size)
|
|
{
|
|
bufferOverrun(tok);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Writing data into array..
|
|
if (varid > 0 &&
|
|
Token::Match(tok, "fgets ( %varid% , %num% , %any% )", varid) &&
|
|
MathLib::isInt(tok->strAt(4)))
|
|
{
|
|
long len = MathLib::toLongNumber(tok->strAt(4));
|
|
if (len < 0 || len > total_size)
|
|
{
|
|
bufferOverrun(tok);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Dangerous usage of strncat..
|
|
if (varid > 0 && Token::Match(tok, "strncat ( %varid% , %any% , %num% )", varid))
|
|
{
|
|
int n = MathLib::toLongNumber(tok->strAt(6));
|
|
if (n < 0 || n >= total_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 = MathLib::toLongNumber(tok->strAt(6)) + MathLib::toLongNumber(tok->strAt(15));
|
|
if (n > total_size)
|
|
strncatUsage(tok->tokAt(9));
|
|
}
|
|
|
|
// Detect few strcat() calls
|
|
if (varid > 0 && Token::Match(tok, "strcat ( %varid% , %str% ) ;", varid))
|
|
{
|
|
size_t charactersAppend = 0;
|
|
const Token *tok2 = tok;
|
|
|
|
while (tok2 && Token::Match(tok2, "strcat ( %varid% , %str% ) ;", varid))
|
|
{
|
|
charactersAppend += Token::getStrLength(tok2->tokAt(4));
|
|
if (charactersAppend >= static_cast<size_t>(total_size))
|
|
{
|
|
bufferOverrun(tok2);
|
|
break;
|
|
}
|
|
tok2 = tok2->tokAt(7);
|
|
}
|
|
}
|
|
|
|
// sprintf..
|
|
if (varid > 0 && Token::Match(tok, "sprintf ( %varid% , %str% [,)]", varid))
|
|
{
|
|
checkSprintfCall(tok, total_size);
|
|
}
|
|
|
|
// snprintf..
|
|
if (varid > 0 && Token::Match(tok, "snprintf ( %varid% , %num% ,", varid))
|
|
{
|
|
int n = MathLib::toLongNumber(tok->strAt(4));
|
|
if (n > total_size)
|
|
outOfBounds(tok->tokAt(4), "snprintf size");
|
|
}
|
|
|
|
// cin..
|
|
if (varid > 0 && Token::Match(tok, "cin >> %varid% ;", varid))
|
|
{
|
|
dangerousStdCin(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% ("))
|
|
{
|
|
// Only perform this checking if showAll setting is enabled..
|
|
if (!_settings->inconclusive)
|
|
continue;
|
|
|
|
unsigned int parlevel = 0, par = 0;
|
|
const Token * tok1 = tok;
|
|
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)
|
|
{
|
|
if (varid > 0 && Token::Match(tok2, "[(,] %varid% [,)]", varid))
|
|
{
|
|
++par;
|
|
tok1 = tok2->next();
|
|
break;
|
|
}
|
|
else if (varid == 0 && Token::Match(tok2, ("[(,] " + varnames + " [,)]").c_str()))
|
|
{
|
|
++par;
|
|
tok1 = tok2->tokAt(varc + 1);
|
|
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..
|
|
std::vector<std::string> parname;
|
|
parname.push_back(ftok->str());
|
|
|
|
const unsigned int parId = ftok->varId();
|
|
|
|
// Goto function body..
|
|
while (ftok && (ftok->str() != "{"))
|
|
ftok = ftok->next();
|
|
ftok = ftok ? ftok->next() : 0;
|
|
|
|
// Don't make recursive checking..
|
|
if (std::find_if(_callStack.begin(), _callStack.end(), TokenStrEquals(tok1->str())) != _callStack.end())
|
|
continue;
|
|
|
|
// Check variable usage in the function..
|
|
_callStack.push_back(tok1);
|
|
checkScope(ftok, parname, size, total_size, parId);
|
|
_callStack.pop_back();
|
|
|
|
// break out..
|
|
break;
|
|
}
|
|
|
|
ftok = ftok->next();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Checking local variables in a scope
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckBufferOverrun::checkGlobalAndLocalVariable()
|
|
{
|
|
int indentlevel = 0;
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
|
|
{
|
|
if (tok->str() == "{")
|
|
++indentlevel;
|
|
|
|
else if (tok->str() == "}")
|
|
--indentlevel;
|
|
|
|
int size = 0;
|
|
std::string type;
|
|
unsigned int varid = 0;
|
|
int nextTok = 0;
|
|
|
|
// if the previous token exists, it must be either a variable name or "[;{}]"
|
|
if (tok->previous() && (!tok->previous()->isName() && !Token::Match(tok->previous(), "[;{}]")))
|
|
continue;
|
|
|
|
if (Token::Match(tok, "%type% *| %var% [ %num% ] [;=]"))
|
|
{
|
|
unsigned int varpos = 1;
|
|
if (tok->next()->str() == "*")
|
|
++varpos;
|
|
size = MathLib::toLongNumber(tok->strAt(varpos + 2));
|
|
type = tok->strAt(varpos - 1);
|
|
varid = tok->tokAt(varpos)->varId();
|
|
nextTok = varpos + 5;
|
|
}
|
|
else if (Token::Match(tok, "%type% *| %var% [ %var% ] [;=]"))
|
|
{
|
|
unsigned int varpos = 1;
|
|
if (tok->next()->str() == "*")
|
|
++varpos;
|
|
|
|
// make sure the variable is defined
|
|
if (tok->tokAt(varpos + 2)->varId() == 0)
|
|
continue; // FIXME we loose the check for negative index when we bail
|
|
|
|
// get maximum size from type
|
|
// find where this token is defined
|
|
const Token *index_type = Token::findmatch(_tokenizer->tokens(), "%varid%", tok->tokAt(varpos + 2)->varId());
|
|
|
|
index_type = index_type->previous();
|
|
|
|
if (index_type->str() == "char")
|
|
{
|
|
if (index_type->isUnsigned())
|
|
size = UCHAR_MAX + 1;
|
|
else if (index_type->isSigned())
|
|
size = SCHAR_MAX + 1;
|
|
else
|
|
size = CHAR_MAX + 1;
|
|
}
|
|
else if (index_type->str() == "short")
|
|
{
|
|
if (index_type->isUnsigned())
|
|
size = USHRT_MAX + 1;
|
|
else
|
|
size = SHRT_MAX + 1;
|
|
}
|
|
|
|
// checkScope assumes size is signed int so we limit the following sizes to INT_MAX
|
|
else if (index_type->str() == "int")
|
|
{
|
|
if (index_type->isUnsigned())
|
|
size = INT_MAX; // should be UINT_MAX + 1U;
|
|
else
|
|
size = INT_MAX; // should be INT_MAX + 1U;
|
|
}
|
|
else if (index_type->str() == "long")
|
|
{
|
|
if (index_type->isUnsigned())
|
|
{
|
|
if (index_type->isLong())
|
|
size = INT_MAX; // should be ULLONG_MAX + 1ULL;
|
|
else
|
|
size = INT_MAX; // should be ULONG_MAX + 1UL;
|
|
}
|
|
else
|
|
{
|
|
if (index_type->isLong())
|
|
size = INT_MAX; // should be LLONG_MAX + 1LL;
|
|
else
|
|
size = INT_MAX; // should be LONG_MAX + 1L;
|
|
}
|
|
}
|
|
|
|
type = tok->strAt(varpos - 1);
|
|
varid = tok->tokAt(varpos)->varId();
|
|
nextTok = varpos + 5;
|
|
}
|
|
else if (indentlevel > 0 && Token::Match(tok, "[*;{}] %var% = new %type% [ %num% ]"))
|
|
{
|
|
size = MathLib::toLongNumber(tok->strAt(6));
|
|
type = tok->strAt(4);
|
|
varid = tok->tokAt(1)->varId();
|
|
nextTok = 8;
|
|
}
|
|
else if (indentlevel > 0 && Token::Match(tok, "[*;{}] %var% = new %type% ( %num% )"))
|
|
{
|
|
size = 1;
|
|
type = tok->strAt(4);
|
|
varid = tok->tokAt(1)->varId();
|
|
nextTok = 8;
|
|
}
|
|
else if (indentlevel > 0 && Token::Match(tok, "[*;{}] %var% = malloc ( %num% ) ;"))
|
|
{
|
|
size = MathLib::toLongNumber(tok->strAt(5));
|
|
type = "char"; // minimum type, typesize=1
|
|
varid = tok->tokAt(1)->varId();
|
|
nextTok = 7;
|
|
|
|
if (varid > 0)
|
|
{
|
|
// get type of variable
|
|
const Token *declTok = Token::findmatch(_tokenizer->tokens(), "[;{}] %type% * %varid% ;", varid);
|
|
if (!declTok)
|
|
continue;
|
|
|
|
type = declTok->next()->str();
|
|
|
|
// malloc() gets count of bytes and not count of
|
|
// elements, so we should calculate count of elements
|
|
// manually
|
|
unsigned int sizeOfType = _tokenizer->sizeOfType(declTok->next());
|
|
if (sizeOfType > 0)
|
|
size /= sizeOfType;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
continue;
|
|
}
|
|
|
|
if (varid == 0)
|
|
continue;
|
|
|
|
Token sizeTok(0);
|
|
sizeTok.str(type);
|
|
int total_size = size * _tokenizer->sizeOfType(&sizeTok);
|
|
if (total_size == 0)
|
|
continue;
|
|
|
|
// The callstack is empty
|
|
_callStack.clear();
|
|
std::vector<std::string> v;
|
|
checkScope(tok->tokAt(nextTok), v, size, total_size, varid);
|
|
}
|
|
}
|
|
//---------------------------------------------------------------------------
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
// Checking member variables of structs..
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckBufferOverrun::checkStructVariable()
|
|
{
|
|
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())
|
|
{
|
|
// skip inner scopes..
|
|
if (tok2->next() && tok2->next()->str() == "{")
|
|
{
|
|
tok2 = tok2->next()->link();
|
|
continue;
|
|
}
|
|
|
|
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;
|
|
|
|
std::vector<std::string> varname(2, "");
|
|
const unsigned int varId = tok2->tokAt(ivar)->varId();
|
|
varname[1] = tok2->strAt(ivar);
|
|
int arrsize = MathLib::toLongNumber(tok2->strAt(ivar + 2));
|
|
int total_size = arrsize * _tokenizer->sizeOfType(tok2->tokAt(1));
|
|
if (tok2->tokAt(2)->str() == "*")
|
|
total_size = arrsize * _tokenizer->sizeOfType(tok2->tokAt(2));
|
|
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, ") {"))
|
|
{
|
|
std::vector<std::string> v;
|
|
checkScope(tok4->tokAt(2), v, arrsize, total_size, varId);
|
|
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..
|
|
checkScope(CheckTok, varname, arrsize, total_size, 0);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
//---------------------------------------------------------------------------
|
|
|
|
void CheckBufferOverrun::bufferOverrun()
|
|
{
|
|
checkGlobalAndLocalVariable();
|
|
checkStructVariable();
|
|
}
|
|
//---------------------------------------------------------------------------
|
|
|
|
|
|
int CheckBufferOverrun::countSprintfLength(const std::string &input_string, const std::list<const Token*> ¶meters)
|
|
{
|
|
bool percentCharFound = false;
|
|
int input_string_size = 1;
|
|
bool handleNextParameter = false;
|
|
std::string digits_string = "";
|
|
bool i_d_x_f_found = false;
|
|
std::list<const Token*>::const_iterator paramIter = parameters.begin();
|
|
unsigned int parameterLength = 0;
|
|
for (std::string::size_type i = 0; i < input_string.length(); ++i)
|
|
{
|
|
if (input_string[i] == '\\')
|
|
{
|
|
if (input_string[i+1] == '0')
|
|
break;
|
|
|
|
++input_string_size;
|
|
++i;
|
|
continue;
|
|
}
|
|
|
|
if (percentCharFound)
|
|
{
|
|
switch (input_string[i])
|
|
{
|
|
case 'f':
|
|
case 'x':
|
|
case 'X':
|
|
case 'i':
|
|
i_d_x_f_found = true;
|
|
case 'c':
|
|
case 'e':
|
|
case 'E':
|
|
case 'g':
|
|
case 'o':
|
|
case 'u':
|
|
case 'p':
|
|
case 'n':
|
|
handleNextParameter = true;
|
|
break;
|
|
case 'd':
|
|
i_d_x_f_found = true;
|
|
if (paramIter != parameters.end() && *paramIter && (*paramIter)->str()[0] != '"')
|
|
parameterLength = (*paramIter)->str().length();
|
|
|
|
handleNextParameter = true;
|
|
break;
|
|
case 's':
|
|
if (paramIter != parameters.end() && *paramIter && (*paramIter)->str()[0] == '"')
|
|
parameterLength = Token::getStrLength(*paramIter);
|
|
|
|
handleNextParameter = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (input_string[i] == '%')
|
|
percentCharFound = !percentCharFound;
|
|
else if (percentCharFound)
|
|
{
|
|
digits_string.append(1, input_string[i]);
|
|
}
|
|
|
|
if (!percentCharFound)
|
|
input_string_size++;
|
|
|
|
if (handleNextParameter)
|
|
{
|
|
unsigned int tempDigits = std::abs(std::atoi(digits_string.c_str()));
|
|
if (i_d_x_f_found)
|
|
tempDigits = std::max(static_cast<int>(tempDigits), 1);
|
|
|
|
if (digits_string.find('.') != std::string::npos)
|
|
{
|
|
const std::string endStr = digits_string.substr(digits_string.find('.') + 1);
|
|
unsigned int maxLen = std::max(std::abs(std::atoi(endStr.c_str())), 1);
|
|
|
|
if (input_string[i] == 's')
|
|
{
|
|
// For strings, the length after the dot "%.2s" will limit
|
|
// the length of the string.
|
|
if (parameterLength > maxLen)
|
|
parameterLength = maxLen;
|
|
}
|
|
else
|
|
{
|
|
// For integers, the length after the dot "%.2d" can
|
|
// increase required length
|
|
if (tempDigits < maxLen)
|
|
tempDigits = maxLen;
|
|
}
|
|
}
|
|
|
|
if (tempDigits < parameterLength)
|
|
input_string_size += parameterLength;
|
|
else
|
|
input_string_size += tempDigits;
|
|
|
|
parameterLength = 0;
|
|
digits_string = "";
|
|
i_d_x_f_found = false;
|
|
percentCharFound = false;
|
|
handleNextParameter = false;
|
|
if (paramIter != parameters.end())
|
|
++paramIter;
|
|
}
|
|
}
|
|
|
|
return input_string_size;
|
|
}
|
|
|
|
|
|
void CheckBufferOverrun::checkSprintfCall(const Token *tok, int size)
|
|
{
|
|
std::list<const Token*> parameters;
|
|
if (tok->tokAt(5)->str() == ",")
|
|
{
|
|
const Token *end = tok->next()->link();
|
|
for (const Token *tok2 = tok->tokAt(5); tok2 && tok2 != end; tok2 = tok2->next())
|
|
{
|
|
if (Token::Match(tok2, ", %any% [,)]"))
|
|
{
|
|
|
|
if (Token::Match(tok2->next(), "%str%"))
|
|
parameters.push_back(tok2->next());
|
|
|
|
else if (Token::Match(tok2->next(), "%num%"))
|
|
parameters.push_back(tok2->next());
|
|
|
|
// TODO, get value of the variable if possible and use that instead of 0
|
|
else
|
|
parameters.push_back(0);
|
|
}
|
|
else
|
|
{
|
|
// Parameter is more complex, than just a value or variable. Ignore it for now
|
|
// and skip to next token.
|
|
parameters.push_back(0);
|
|
int ind = 0;
|
|
for (const Token *tok3 = tok2->next(); tok3; tok3 = tok3->next())
|
|
{
|
|
if (tok3->str() == "(")
|
|
++ind;
|
|
|
|
else if (tok3->str() == ")")
|
|
{
|
|
--ind;
|
|
if (ind < 0)
|
|
break;
|
|
}
|
|
|
|
else if (ind == 0 && tok3->str() == ",")
|
|
{
|
|
tok2 = tok3->previous();
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (ind < 0)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
int len = countSprintfLength(tok->tokAt(4)->strValue(), parameters);
|
|
if (len > size)
|
|
{
|
|
bufferOverrun(tok);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
|
|
#include "executionpath.h"
|
|
|
|
/// @addtogroup Checks
|
|
/// @{
|
|
|
|
|
|
class ArrayInfo
|
|
{
|
|
public:
|
|
/** type size in bytes */
|
|
unsigned int type_size;
|
|
|
|
/** number of elements of array */
|
|
unsigned int num;
|
|
};
|
|
|
|
|
|
/**
|
|
* @brief %Check for buffer overruns (using ExecutionPath)
|
|
*/
|
|
|
|
class ExecutionPathBufferOverrun : public ExecutionPath
|
|
{
|
|
public:
|
|
/** Startup constructor */
|
|
ExecutionPathBufferOverrun(Check *c, const std::map<unsigned int, ArrayInfo> &arrayinfo)
|
|
: ExecutionPath(c, 0), arrayInfo(arrayinfo)
|
|
{
|
|
}
|
|
|
|
private:
|
|
/** Copy this check */
|
|
ExecutionPath *copy()
|
|
{
|
|
return new ExecutionPathBufferOverrun(*this);
|
|
}
|
|
|
|
/** @brief buffer information */
|
|
const std::map<unsigned int, ArrayInfo> &arrayInfo;
|
|
|
|
/** no implementation => compiler error if used by accident */
|
|
void operator=(const ExecutionPathBufferOverrun &);
|
|
|
|
/** internal constructor for creating extra checks */
|
|
ExecutionPathBufferOverrun(Check *c, const std::map<unsigned int, ArrayInfo> &arrayinfo, unsigned int varid_)
|
|
: ExecutionPath(c, varid_),
|
|
arrayInfo(arrayinfo)
|
|
{
|
|
// Pretend that variables are initialized to 0
|
|
// This checking is not about uninitialized variables
|
|
value = 0;
|
|
}
|
|
|
|
unsigned int value;
|
|
|
|
/** @brief Assign value to a variable */
|
|
static void assign_value(std::list<ExecutionPath *> &checks, unsigned int varid, const std::string &value)
|
|
{
|
|
if (varid == 0)
|
|
return;
|
|
|
|
std::list<ExecutionPath *>::const_iterator it;
|
|
for (it = checks.begin(); it != checks.end(); ++it)
|
|
{
|
|
ExecutionPathBufferOverrun *c = dynamic_cast<ExecutionPathBufferOverrun *>(*it);
|
|
if (c && c->varId == varid)
|
|
c->value = MathLib::toLongNumber(value);
|
|
}
|
|
}
|
|
|
|
/** @brief Found array usage.. */
|
|
static void array_index(const Token *tok, std::list<ExecutionPath *> &checks, unsigned int varid1, unsigned int varid2)
|
|
{
|
|
if (checks.empty() || varid1 == 0 || varid2 == 0)
|
|
return;
|
|
|
|
// Locate array info corresponding to varid1
|
|
ArrayInfo ai;
|
|
{
|
|
ExecutionPathBufferOverrun *c = dynamic_cast<ExecutionPathBufferOverrun *>(checks.front());
|
|
std::map<unsigned int, ArrayInfo>::const_iterator it;
|
|
it = c->arrayInfo.find(varid1);
|
|
if (it == c->arrayInfo.end())
|
|
return;
|
|
ai = it->second;
|
|
}
|
|
|
|
// Check if varid2 variable has a value that is out-of-bounds
|
|
std::list<ExecutionPath *>::const_iterator it;
|
|
for (it = checks.begin(); it != checks.end(); ++it)
|
|
{
|
|
ExecutionPathBufferOverrun *c = dynamic_cast<ExecutionPathBufferOverrun *>(*it);
|
|
if (c && c->varId == varid2 && c->value >= ai.num)
|
|
{
|
|
// variable value is out of bounds, report error
|
|
CheckBufferOverrun *checkBufferOverrun = dynamic_cast<CheckBufferOverrun *>(c->owner);
|
|
if (checkBufferOverrun)
|
|
{
|
|
checkBufferOverrun->arrayIndexOutOfBounds(tok, ai.num, c->value);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
const Token *parse(const Token &tok, std::list<ExecutionPath *> &checks) const
|
|
{
|
|
if (Token::Match(tok.previous(), "[;{}]"))
|
|
{
|
|
// Declaring variable..
|
|
if (Token::Match(&tok, "%type% %var% ;") && tok.isStandardType())
|
|
{
|
|
checks.push_back(new ExecutionPathBufferOverrun(owner, arrayInfo, tok.next()->varId()));
|
|
return tok.tokAt(2);
|
|
}
|
|
|
|
// Assign variable..
|
|
if (Token::Match(&tok, "%var% = %num% ;"))
|
|
{
|
|
assign_value(checks, tok.varId(), tok.strAt(2));
|
|
return tok.tokAt(3);
|
|
}
|
|
}
|
|
|
|
// Assign variable (unknown value = 0)..
|
|
if (Token::Match(&tok, "%var% ="))
|
|
{
|
|
assign_value(checks, tok.varId(), "0");
|
|
return &tok;
|
|
}
|
|
|
|
// Array index..
|
|
if (Token::Match(&tok, "%var% [ %var% ]"))
|
|
{
|
|
array_index(&tok, checks, tok.varId(), tok.tokAt(2)->varId());
|
|
return tok.tokAt(3);
|
|
}
|
|
|
|
return &tok;
|
|
}
|
|
};
|
|
|
|
/// @}
|
|
|
|
|
|
void CheckBufferOverrun::executionPaths()
|
|
{
|
|
// Parse all tokens and extract array info..
|
|
std::map<unsigned int, ArrayInfo> arrayInfo;
|
|
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
|
|
{
|
|
if (Token::Match(tok, "[;{}] %type% %var% [ %num% ] ;"))
|
|
{
|
|
const unsigned int varid(tok->tokAt(2)->varId());
|
|
ArrayInfo ai;
|
|
ai.type_size = _tokenizer->sizeOfType(tok->next());
|
|
ai.num = MathLib::toLongNumber(tok->strAt(4));
|
|
arrayInfo[varid] = ai;
|
|
}
|
|
}
|
|
|
|
// Perform checking - check how the arrayInfo arrays are used
|
|
ExecutionPathBufferOverrun c(this, arrayInfo);
|
|
checkExecutionPaths(_tokenizer->tokens(), &c);
|
|
}
|
|
|
|
|
|
|