cppcheck/lib/checkbufferoverrun.h

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2009 Daniel Marjamäki and Cppcheck team.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


//---------------------------------------------------------------------------
#ifndef CheckBufferOverrunH
#define CheckBufferOverrunH
//---------------------------------------------------------------------------

#include "check.h"
#include "settings.h"
#include <list>
#include <vector>
#include <string>

class ErrorLogger;
class Token;
class Tokenizer;

/// @addtogroup Checks
/// @{

/**
 * @brief buffer overruns and array index out of bounds
 *
 * Buffer overrun and array index out of bounds are pretty much the same.
 * But I generally use 'array index' if the code contains []. And the given
 * index is out of bounds.
 * I generally use 'buffer overrun' if you for example call a strcpy or
 * other function and pass a buffer and reads or writes too much data.
 */
class CheckBufferOverrun : public Check
{
public:

    /** This constructor is used when registering the CheckClass */
    CheckBufferOverrun() : Check()
    { }

    /** This constructor is used when running checks. */
    CheckBufferOverrun(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
            : Check(tokenizer, settings, errorLogger)
    { }

    void runSimplifiedChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
    {
        CheckBufferOverrun checkBufferOverrun(tokenizer, settings, errorLogger);
        checkBufferOverrun.bufferOverrun();

        /** ExecutionPath checking.. */
        checkBufferOverrun.executionPaths();
    }

    /** @brief %Check for buffer overruns */
    void bufferOverrun();

    /** @brief %Check for buffer overruns by inspecting execution paths */
    void executionPaths();

    /**
     * @brief Get minimum length of format string result
     * @param input_string format string
     * @param parameters given parameters to sprintf
     * @return minimum length of resulting string
     */
    static int countSprintfLength(const std::string &input_string, const std::list<const Token*> &parameters);

    /**
     * @brief %Check code that matches: "sprintf ( %varid% , %str% [,)]" when varid is not 0,
     * and report found errors.
     * @param tok The "sprintf" token.
     * @param size The size of the buffer where sprintf is writing.
     */
    void checkSprintfCall(const Token *tok, int size);

    /** Check for buffer overruns - locate struct variables and check them with the .._CheckScope function */
    void checkStructVariable();

    /** Check for buffer overruns - locate global variables and local function variables and check them with the checkScope function */
    void checkGlobalAndLocalVariable();

    /** Check for buffer overruns - this is the function that performs the actual checking */
    void checkScope(const Token *tok, const std::vector<std::string> &varname, const int size, const int total_size, unsigned int varid);

    /** callstack - used during intra-function checking */
    std::list<const Token *> _callStack;

    void arrayIndexOutOfBounds(const Token *tok, int size, int index);
    void arrayIndexOutOfBounds(int size, int index);
    void bufferOverrun(const Token *tok, const std::string &varnames = "");
    void dangerousStdCin(const Token *tok);
    void strncatUsage(const Token *tok);
    void outOfBounds(const Token *tok, const std::string &what);
    void sizeArgumentAsChar(const Token *tok);
    void terminateStrncpyError(const Token *tok);

    void getErrorMessages()
    {
        arrayIndexOutOfBounds(0, 2, 2);
        bufferOverrun(0, std::string("buffer"));
        dangerousStdCin(0);
        strncatUsage(0);
        outOfBounds(0, "index");
        sizeArgumentAsChar(0);
        terminateStrncpyError(0);
    }

    std::string name() const
    {
        return "Bounds checking";
    }

    std::string classInfo() const
    {
        return "out of bounds checking";
    }
};
/// @}
//---------------------------------------------------------------------------
#endif