cppcheck/lib/checkbufferoverrun.cpp

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2012 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/>.
 */

//---------------------------------------------------------------------------
// Buffer overrun..
//---------------------------------------------------------------------------

#include "checkbufferoverrun.h"

#include "tokenize.h"
#include "errorlogger.h"
#include "mathlib.h"
#include "symboldatabase.h"

#include <algorithm>
#include <sstream>
#include <list>
#include <cassert>     // <- assert
#include <cstdlib>

//---------------------------------------------------------------------------

// Register this check class (by creating a static instance of it)
namespace {
    CheckBufferOverrun instance;
}

//---------------------------------------------------------------------------

static void makeArrayIndexOutOfBoundsError(std::ostream& oss, const CheckBufferOverrun::ArrayInfo &arrayInfo, const std::vector<MathLib::bigint> &index)
{
    oss << "Array '" << arrayInfo.varname();
    for (unsigned int i = 0; i < arrayInfo.num().size(); ++i)
        oss << "[" << arrayInfo.num(i) << "]";
    if (index.size() == 1)
        oss << "' accessed at index " << index[0] << ", which is";
    else {
        oss << "' index " << arrayInfo.varname();
        for (unsigned int i = 0; i < index.size(); ++i)
            oss << "[" << index[i] << "]";
    }
    oss << " out of bounds.";
}
void CheckBufferOverrun::arrayIndexOutOfBoundsError(const Token *tok, const ArrayInfo &arrayInfo, const std::vector<MathLib::bigint> &index)
{
    std::ostringstream oss;
    makeArrayIndexOutOfBoundsError(oss, arrayInfo, index);
    reportError(tok, Severity::error, "arrayIndexOutOfBounds", oss.str());
}

void CheckBufferOverrun::arrayIndexOutOfBoundsError(const std::list<const Token *> &callstack, const ArrayInfo &arrayInfo, const std::vector<MathLib::bigint> &index)
{
    std::ostringstream oss;
    makeArrayIndexOutOfBoundsError(oss, arrayInfo, index);
    reportError(callstack, Severity::error, "arrayIndexOutOfBounds", oss.str());
}

static std::string bufferOverrunMessage(std::string varnames)
{
    varnames.erase(std::remove(varnames.begin(), varnames.end(), ' '), varnames.end());

    std::string errmsg("Buffer is accessed out of bounds");
    if (!varnames.empty())
        errmsg += ": " + varnames;
    else
        errmsg += ".";

    return errmsg;
}

void CheckBufferOverrun::bufferOverrunError(const Token *tok, const std::string &varnames)
{
    reportError(tok, Severity::error, "bufferAccessOutOfBounds", bufferOverrunMessage(varnames));
}


void CheckBufferOverrun::bufferOverrunError(const std::list<const Token *> &callstack, const std::string &varnames)
{
    reportError(callstack, Severity::error, "bufferAccessOutOfBounds", bufferOverrunMessage(varnames));
}

void CheckBufferOverrun::possibleBufferOverrunError(const Token *tok, const std::string &src, const std::string &dst, bool cat)
{
    if (cat)
        reportError(tok, Severity::warning, "possibleBufferAccessOutOfBounds",
                    "Possible buffer overflow if strlen(" + src + ") is larger than sizeof(" + dst + ")-strlen(" + dst +").\n"
                    "Possible buffer overflow if strlen(" + src + ") is larger than sizeof(" + dst + ")-strlen(" + dst +"). "
                    "The source buffer is larger than the destination buffer so there is the potential for overflowing the destination buffer.");
    else
        reportError(tok, Severity::warning, "possibleBufferAccessOutOfBounds",
                    "Possible buffer overflow if strlen(" + src + ") is larger than or equal to sizeof(" + dst + ").\n"
                    "Possible buffer overflow if strlen(" + src + ") is larger than or equal to sizeof(" + dst + "). "
                    "The source buffer is larger than the destination buffer so there is the potential for overflowing the destination buffer.");
}

void CheckBufferOverrun::possibleReadlinkBufferOverrunError(const Token* tok, const std::string &funcname, const std::string &varname)
{
    const std::string errmsg = funcname + "() might return the full size of '" + varname + "'. Lower the supplied size by one.\n" +
                               funcname + "() might return the full size of '" + varname + "'. "
                               "If a " + varname + "[len] = '\\0'; statement follows, it will overrun the buffer. Lower the supplied size by one.";

    reportError(tok, Severity::warning, "possibleReadlinkBufferOverrun", errmsg, true);
}

void CheckBufferOverrun::strncatUsageError(const Token *tok)
{
    if (_settings && !_settings->isEnabled("style"))
        return;

    reportError(tok, Severity::warning, "strncatUsage",
                "Dangerous usage of strncat - 3rd parameter is the maximum number of characters to append.\n"
                "strncat appends at max its 3rd parameter's amount of characters. The safe way to use "
                "strncat is to calculate remaining space in the buffer and use it as 3rd parameter.");
}

void CheckBufferOverrun::outOfBoundsError(const Token *tok, const std::string &what, const bool show_size_info, const MathLib::bigint &supplied_size, const MathLib::bigint &actual_size)
{
    std::ostringstream oss;

    oss << what << " is out of bounds";
    if (show_size_info)
        oss << ": Supplied size " << supplied_size << " is larger than actual size " << actual_size;
    oss << '.';
    reportError(tok, Severity::error, "outOfBounds", oss.str());
}

void CheckBufferOverrun::pointerOutOfBoundsError(const Token *tok, const std::string &object)
{
    reportError(tok, Severity::portability, "pointerOutOfBounds", "Undefined behaviour: Pointer arithmetic result does not point into or just past the end of the " + object + ".\n"
                "Undefined behaviour: The result of this pointer arithmetic does not point into or just one element past the end of the " + object + ". Further information: https://www.securecoding.cert.org/confluence/display/seccode/ARR30-C.+Do+not+form+or+use+out+of+bounds+pointers+or+array+subscripts");
}

void CheckBufferOverrun::sizeArgumentAsCharError(const Token *tok)
{
    if (_settings && !_settings->isEnabled("style"))
        return;
    reportError(tok, Severity::warning, "sizeArgumentAsChar", "The size argument is given as a char constant.");
}


void CheckBufferOverrun::terminateStrncpyError(const Token *tok, const std::string &varname)
{
    reportError(tok, Severity::warning, "terminateStrncpy",
                "The buffer '" + varname + "' may not be null-terminated after the call to strncpy().\n"
                "If the source string's size fits or exceeds the given size, strncpy() does not add a "
                "zero at the end of the buffer. This causes bugs later in the code if the code "
                "assumes buffer is null-terminated.", true);
}

void CheckBufferOverrun::cmdLineArgsError(const Token *tok)
{
    reportError(tok, Severity::error, "insecureCmdLineArgs", "Buffer overrun possible for long command line arguments.");
}

void CheckBufferOverrun::bufferNotZeroTerminatedError(const Token *tok, const std::string &varname, const std::string &function)
{
    const std::string errmsg = "The buffer '" + varname + "' is not null-terminated after the call to " + function + "().\n"
                               "The buffer '" + varname + "' is not null-terminated after the call to " + function + "(). "
                               "This will cause bugs later in the code if the code assumes the buffer is null-terminated.";

    reportError(tok, Severity::warning, "bufferNotZeroTerminated", errmsg, true);
}

//---------------------------------------------------------------------------


//---------------------------------------------------------------------------
// Check array usage..
//---------------------------------------------------------------------------

/**
 * @brief This is a helper class to be used with std::find_if
 */
class TokenStrEquals {
public:
    /**
     * @param str Token::str() is compared against this.
     */
    explicit TokenStrEquals(const std::string &str)
        : value(str) {
    }

    /**
     * Called automatically by std::find_if
     * @param tok Token inside the list
     */
    bool operator()(const Token *tok) const {
        return value == tok->str();
    }

private:
    TokenStrEquals& operator=(const TokenStrEquals&); // disallow assignments

    const std::string value;
};


/**
 * bailout if variable is used inside if/else/switch block or if there is "break"
 * @param tok token for "if" or "switch"
 * @param varid variable id
 * @return is bailout recommended?
 */
static bool bailoutIfSwitch(const Token *tok, const unsigned int varid)
{
    // Used later to check if the body belongs to a "if"
    bool is_if = tok->str() == "if";

    const Token* end = tok->linkAt(1)->linkAt(1);
    if (Token::simpleMatch(end, "} else {")) // scan the else-block
        end = end->linkAt(2);
    for (; tok != end; tok = tok->next()) {
        // If scanning a "if" block then bailout for "break"
        if (is_if && (tok->str() == "break" || tok->str() == "continue"))
            return true;

        // bailout for "return"
        else if (tok->str() == "return")
            return true;

        // bailout if varid is found
        else if (tok->varId() == varid)
            return true;
    }

    // No bailout stuff found => return false
    return false;
}

/**
 * Parse for loop initialization statement. Look for a counter variable
 * \param tok [in] first token inside the parentheses
 * \param varid [out] varid of counter variable
 * \param varname [out] name of counter variable
 * \param init_value [out] init value of counter variable
 * \return success => pointer to the for loop condition. fail => 0. If 0 is returned and varname has been set then there is
 * a missing varid for the counter variable
 */
static const Token *for_init(const Token *tok, unsigned int &varid, std::string &varname, std::string &init_value)
{
    if (Token::Match(tok, "%var% = %any% ;")) {
        if (tok->tokAt(2)->isNumber()) {
            init_value = tok->strAt(2);
        }

        varid = tok->varId();
        varname = tok->str();
        tok = tok->tokAt(4);

        if (varid == 0)
            return 0;  // failed
    } else if (Token::Match(tok, "%type% %var% = %any% ;")) {
        if (tok->tokAt(3)->isNumber()) {
            init_value = tok->strAt(3);
        }

        varid = tok->next()->varId();
        varname = tok->next()->str();
        tok = tok->tokAt(5);
    } else if (Token::Match(tok, "%type% %type% %var% = %any% ;")) {
        if (tok->tokAt(4)->isNumber()) {
            init_value = tok->strAt(4);
        }

        varid = tok->tokAt(2)->varId();
        varname = tok->strAt(2);
        tok = tok->tokAt(6);
    } else
        return 0;

    if (!init_value.empty() && (Token::Match(tok, "-- %varid%", varid) || Token::Match(tok, "%varid% --", varid))) {
        init_value = MathLib::subtract(init_value, "1");
    }

    return tok;
}


/** Parse for condition */
static bool for_condition(const Token *tok2, unsigned int varid, std::string &min_value, std::string &max_value, bool &maxMinFlipped)
{
    if (Token::Match(tok2, "%varid% < %num% ;|&&|%oror%", varid) ||
        Token::Match(tok2, "%varid% != %num% ; ++ %varid%", varid) ||
        Token::Match(tok2, "%varid% != %num% ; %varid% ++", varid)) {
        maxMinFlipped = false;
        const MathLib::bigint value = MathLib::toLongNumber(tok2->strAt(2));
        max_value = MathLib::longToString(value - 1);
    } else if (Token::Match(tok2, "%varid% <= %num% ;|&&|%oror%", varid)) {
        maxMinFlipped = false;
        max_value = tok2->strAt(2);
    } else if (Token::Match(tok2, "%num% < %varid% ;|&&|%oror%", varid) ||
               Token::Match(tok2, "%num% != %varid% ; ++ %varid%", varid) ||
               Token::Match(tok2, "%num% != %varid% ; %varid% ++", varid)) {
        maxMinFlipped = true;
        const MathLib::bigint value = MathLib::toLongNumber(tok2->str());
        max_value = min_value;
        min_value = MathLib::longToString(value + 1);
    } else if (Token::Match(tok2, "%num% <= %varid% ;|&&|%oror%", varid)) {
        maxMinFlipped = true;
        max_value = min_value;
        min_value = tok2->str();
    } else {
        // parse condition
        while (tok2 && tok2->str() != ";") {
            if (tok2->str() == "(")
                tok2 = tok2->link();
            else if (tok2->str() == ")")    // unexpected ")" => break
                break;
            if (tok2->str() == "&&" || tok2->str() == "||") {
                if (for_condition(tok2->next(), varid, min_value, max_value, maxMinFlipped))
                    return true;
            }
            tok2 = tok2->next();
        }
        return false;
    }

    return true;
}



/**
 * calculate maximum value of loop variable
 * @param stepvalue token that contains the step value
 * @param min_value the minimum value of loop variable
 * @param max_value maximum value of the loop variable
 */
static bool for_maxvalue(const Token * const stepvalue, const std::string &min_value, std::string &max_value)
{
    if (!MathLib::isInt(stepvalue->str()))
        return false;

    // We have for example code: "for(i=2;i<22;i+=6)
    // We can calculate that max value for i is 20, not 21
    // 21-2 = 19
    // 19/6 = 3
    // 6*3+2 = 20
    const MathLib::bigint num = MathLib::toLongNumber(stepvalue->str());
    MathLib::bigint max = MathLib::toLongNumber(max_value);
    const MathLib::bigint min = MathLib::toLongNumber(min_value);
    max = ((max - min) / num) * num + min;
    max_value = MathLib::longToString(max);
    return true;
}


/**
 * Parse the third sub-statement in for head
 * \param tok first token
 * \param varid variable id of counter
 * \param min_value min value of counter
 * \param max_value max value of counter
 * \param maxMinFlipped counting from max to min
 */
static bool for3(const Token * const tok,
                 unsigned int varid,
                 std::string &min_value,
                 std::string &max_value,
                 const bool maxMinFlipped)
{
    assert(tok != 0);
    if (Token::Match(tok, "%varid% += %num% )", varid) ||
        Token::Match(tok, "%varid%  = %num% + %varid% )", varid)) {
        if (!for_maxvalue(tok->tokAt(2), min_value, max_value))
            return false;
    } else if (Token::Match(tok, "%varid% = %varid% + %num% )", varid)) {
        if (!for_maxvalue(tok->tokAt(4), min_value, max_value))
            return false;
    } else if (Token::Match(tok, "%varid% -= %num% )", varid) ||
               Token::Match(tok, "%varid%  = %num% - %varid% )", varid)) {
        if (!for_maxvalue(tok->tokAt(2), min_value, max_value))
            return false;
    } else if (Token::Match(tok, "%varid% = %varid% - %num% )", varid)) {
        if (!for_maxvalue(tok->tokAt(4), min_value, max_value))
            return false;
    } else if (Token::Match(tok, "--| %varid% --| )", varid)) {
        if (!maxMinFlipped && MathLib::toLongNumber(min_value) < MathLib::toLongNumber(max_value)) {
            // Code relies on the fact that integer will overflow:
            // for (unsigned int i = 3; i < 5; --i)

            // Set min value in this case to zero.
            max_value = min_value;
            min_value = "0";
        }
    } else if (! Token::Match(tok, "++| %varid% ++| )", varid)) {
        return false;
    }
    return true;
}



/**
 * Check is the counter variable increased elsewhere inside the loop or used
 * for anything else except reading
 * \param tok1 first token of for-body
 * \param varid counter variable id
 * \return bailout needed => true
 */
static bool for_bailout(const Token * const tok1, unsigned int varid)
{
    for (const Token *loopTok = tok1; loopTok && loopTok != tok1->link(); loopTok = loopTok->next()) {
        if (loopTok->varId() == varid) {
            // Counter variable used inside loop
            if (Token::Match(loopTok->next(), "+=|-=|++|--|=") ||
                (loopTok->previous()->type() == Token::eIncDecOp)) {
                return true;
            }
        }
    }
    return false;
}


void CheckBufferOverrun::parse_for_body(const Token *tok, const ArrayInfo &arrayInfo, const std::string &strindex, bool condition_out_of_bounds, unsigned int counter_varid, const std::string &min_counter_value, const std::string &max_counter_value)
{
    const std::string pattern = (arrayInfo.varid() ? std::string("%varid%") : arrayInfo.varname()) + " [ " + strindex + " ]";

    for (const Token* tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
        // TODO: try to reduce false negatives. This is just a quick fix
        // for TestBufferOverrun::array_index_for_question
        if (tok2->str() == "?")
            break;

        if (Token::simpleMatch(tok2, "for (") && Token::simpleMatch(tok2->next()->link(), ") {")) {
            const Token *endpar = tok2->next()->link();
            const Token *startbody = endpar->next();
            const Token *endbody = startbody->link();
            tok2 = endbody;
            continue;
        }

        if (Token::Match(tok2, "if|switch")) {
            if (bailoutIfSwitch(tok2, arrayInfo.varid()))
                break;
        }

        if (condition_out_of_bounds && Token::Match(tok2, pattern.c_str(), arrayInfo.varid())) {
            bufferOverrunError(tok2, arrayInfo.varname());
            break;
        }

        else if (arrayInfo.varid() && tok2->varId() && counter_varid > 0 && !min_counter_value.empty() && !max_counter_value.empty()) {
            // Is the loop variable used to calculate the array index?
            // In this scope it is determined if such calculated
            // array indexes are out of bounds.
            // Only the minimum and maximum results of the calculation is
            // determined

            // Minimum calculated array index
            int min_index = 0;

            // Maximum calculated array index
            int max_index = 0;

            if (Token::Match(tok2, "%varid% [ %var% +|-|*|/ %num% ]", arrayInfo.varid()) &&
                tok2->tokAt(2)->varId() == counter_varid) {
                // operator: +-*/
                const char action = tok2->strAt(3)[0];

                // second operator
                const std::string &second(tok2->strAt(4));

                //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% ]", arrayInfo.varid()) &&
                       tok2->tokAt(4)->varId() == counter_varid) {
                // operator: +-*/
                const char action = tok2->strAt(3)[0];

                // first operand
                const std::string &first(tok2->strAt(2));

                //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());
            }

            else {
                continue;
            }

            //printf("min_index = %d, max_index = %d, size = %d\n", min_index, max_index, size);
            if (min_index < 0 || max_index < 0) {
                std::vector<MathLib::bigint> indexes;
                indexes.push_back(std::min(min_index, max_index));
                arrayIndexOutOfBoundsError(tok2, arrayInfo, indexes);
            }

            // skip 0 length arrays
            if (arrayInfo.num(0) == 0)
                ;

            // taking address.
            else if (tok2->previous()->str() == "&" && max_index == arrayInfo.num(0))
                ;

            else if (arrayInfo.num(0) && (min_index >= arrayInfo.num(0) || max_index >= arrayInfo.num(0))) {
                std::vector<MathLib::bigint> indexes;
                indexes.push_back(std::max(min_index, max_index));
                arrayIndexOutOfBoundsError(tok2, arrayInfo, indexes);
            }
        }
    }
}


void CheckBufferOverrun::checkFunctionParameter(const Token &tok, unsigned int par, const ArrayInfo &arrayInfo, std::list<const Token *> callstack)
{
    // total_size : which parameter in function call takes the total size?
    std::map<std::string, unsigned int> total_size;

    total_size["fgets"] = 2; // The second argument for fgets can't exceed the total size of the array
    total_size["memcmp"] = 3;
    total_size["memcpy"] = 3;
    total_size["memmove"] = 3;
    total_size["memchr"] = 3;

    if (par == 1) {
        // reading from array
        // if it is zero terminated properly there won't be buffer overruns
        total_size["strncat"] = 3;
        total_size["strncpy"] = 3;
        total_size["memset"] = 3;
        total_size["fread"] = 1001;     // parameter 2 * parameter 3
        total_size["fwrite"] = 1001;    // parameter 2 * parameter 3
    }

    else if (par == 2) {
        total_size["read"] = 3;
        total_size["pread"] = 3;
        total_size["write"] = 3;
        total_size["recv"] = 3;
        total_size["recvfrom"] = 3;
        total_size["send"] = 3;
        total_size["sendto"] = 3;
    }

    std::map<std::string, unsigned int>::const_iterator it = total_size.find(tok.str());
    if (it != total_size.end()) {
        if (arrayInfo.element_size() == 0)
            return;

        // arg : the index of the "wanted" argument in the function call.
        unsigned int arg = it->second;

        // Parse function call. When a ',' is seen, arg is decremented.
        // if arg becomes 1 then the current function parameter is the wanted parameter.
        // if arg becomes 1000 then multiply current and next argument.
        const Token *tok2 = tok.tokAt(2)->nextArgument();
        if (arg == 3)
            tok2 = tok2->nextArgument();
        if ((arg == 2 || arg == 3) && tok2) {
            if (Token::Match(tok2, "%num% ,|)")) {
                const MathLib::bigint sz = MathLib::toLongNumber(tok2->str());
                MathLib::bigint elements = 1;
                for (unsigned int i = 0; i < arrayInfo.num().size(); ++i)
                    elements *= arrayInfo.num(i);
                if (sz < 0 || sz > int(elements * arrayInfo.element_size())) {
                    bufferOverrunError(callstack, arrayInfo.varname());
                }
            }

            else if (Token::Match(tok2->next(), ",|)") && tok2->type() == Token::eChar) {
                sizeArgumentAsCharError(tok2);
            }
        } else if (arg == 1001) { // special code. This parameter multiplied with the next must not exceed total_size
            if (Token::Match(tok2, "%num% , %num% ,|)")) {
                const MathLib::bigint sz = MathLib::toLongNumber(MathLib::multiply(tok2->str(), tok2->strAt(2)));
                MathLib::bigint elements = 1;
                for (unsigned int i = 0; i < arrayInfo.num().size(); ++i)
                    elements *= arrayInfo.num(i);
                if (sz < 0 || sz > int(elements * arrayInfo.element_size())) {
                    bufferOverrunError(&tok, arrayInfo.varname());
                }
            }
        }
    }

    // Calling a user function?
    // only 1-dimensional arrays can be checked currently
    else if (arrayInfo.num().size() == 1) {
        const Function* func = _tokenizer->getSymbolDatabase()->findFunctionByName(tok.str(), tok.scope());;
        if (func && func->hasBody) {
            // Get corresponding parameter..
            const Variable* parameter = func->getArgumentVar(par-1);

            // Ensure that it has a compatible size..
            if (!parameter || _tokenizer->sizeOfType(parameter->typeStartToken()) != arrayInfo.element_size())
                return;

            // No variable id occur for instance when:
            // - Variable function arguments: "void f(...)"
            // - Unnamed parameter: "void f(char *)"
            if (parameter->varId() == 0)
                return;

            // Check the parameter usage in the function scope..
            for (const Token* ftok = func->functionScope->classStart; ftok != func->functionScope->classEnd; ftok = ftok->next()) {
                if (Token::Match(ftok, "if|for|while (")) {
                    // bailout if there is buffer usage..
                    if (bailoutIfSwitch(ftok, parameter->varId())) {
                        break;
                    }

                    // no bailout is needed. skip the if-block
                    else {
                        // goto end of if block..
                        ftok = ftok->next()->link()->next()->link();
                        if (Token::simpleMatch(ftok, "} else {"))
                            ftok = ftok->linkAt(2);
                        if (!ftok)
                            break;
                        continue;
                    }
                }

                if (ftok->str() == "}")
                    break;

                if (ftok->varId() == parameter->varId()) {
                    if (Token::Match(ftok->previous(), "-- %var%") ||
                        Token::Match(ftok, "%var% --"))
                        break;

                    if (Token::Match(ftok->previous(), "=|;|{|}|%op% %var% [ %num% ]")) {
                        const MathLib::bigint index = MathLib::toLongNumber(ftok->strAt(2));
                        if (index >= 0 && arrayInfo.num(0) > 0 && index >= arrayInfo.num(0)) {
                            std::list<const Token *> callstack2(callstack);
                            callstack2.push_back(ftok);

                            std::vector<MathLib::bigint> indexes;
                            indexes.push_back(index);

                            arrayIndexOutOfBoundsError(callstack2, arrayInfo, indexes);
                        }
                    }
                }

                // Calling function..
                if (Token::Match(ftok, "%var% (")) {
                    ArrayInfo ai(arrayInfo);
                    ai.varid(parameter->varId());
                    checkFunctionCall(ftok, ai, callstack);
                }
            }
        }
    }
}


void CheckBufferOverrun::checkFunctionCall(const Token *tok, const ArrayInfo &arrayInfo, std::list<const Token *> callstack)
{
    // Don't go deeper than 2 levels, the checking can get very slow
    // when there is no limit
    if (callstack.size() >= 2)
        return;

    // Prevent recursion
    for (std::list<const Token*>::const_iterator it = callstack.begin(); it != callstack.end(); ++it) {
        // Same function name => bail out
        if (tok->str() == (*it)->str())
            return;
    }
    callstack.push_back(tok);

    const Token *tok2 = tok->tokAt(2);
    // 1st parameter..
    if (Token::Match(tok2, "%varid% ,|)", arrayInfo.varid()))
        checkFunctionParameter(*tok, 1, arrayInfo, callstack);
    else if (Token::Match(tok2, "%varid% + %num% ,|)", arrayInfo.varid())) {
        const ArrayInfo ai(arrayInfo.limit(MathLib::toLongNumber(tok2->strAt(2))));
        checkFunctionParameter(*tok, 1, ai, callstack);
    }

    // goto 2nd parameter and check it..
    tok2 = tok2->nextArgument();
    if (Token::Match(tok2, "%varid% ,|)", arrayInfo.varid()))
        checkFunctionParameter(*tok, 2, arrayInfo, callstack);
    else if (Token::Match(tok2, "%varid% + %num% ,|)", arrayInfo.varid())) {
        const ArrayInfo ai(arrayInfo.limit(MathLib::toLongNumber(tok2->strAt(2))));
        checkFunctionParameter(*tok, 2, ai, callstack);
    }
}


void CheckBufferOverrun::checkScopeForBody(const Token *tok, const ArrayInfo &arrayInfo, bool &bailout)
{
    bailout = false;
    const Token *tok2 = tok->tokAt(2);
    const MathLib::bigint size = arrayInfo.num(0);

    // Check if there is a break in the body..
    {
        const Token *bodyStart = tok->next()->link()->next();
        const Token *bodyEnd = bodyStart->link();
        if (Token::findsimplematch(bodyStart, "break ;", bodyEnd))
            return;
    }

    std::string counter_name;
    unsigned int counter_varid = 0;
    std::string counter_init_value;

    tok2 = for_init(tok2, counter_varid, counter_name, counter_init_value);
    if (tok2 == 0 && !counter_name.empty())
        _tokenizer->getSymbolDatabase()->debugMessage(tok, "for loop variable \'" + counter_name + "\' has varid 0.");
    if (tok2 == 0 || counter_varid == 0)
        return;

    bool maxMinFlipped = false;
    std::string min_counter_value = counter_init_value;
    std::string max_counter_value;
    if (!for_condition(tok2, counter_varid, min_counter_value, max_counter_value, maxMinFlipped)) {
        // Can't understand the condition. Check that the start value
        // is used correctly
        const Token *startForScope = tok->next()->link()->next();
        if (!for_bailout(startForScope, counter_varid)) {
            // Get index variable and stopsize.
            bool condition_out_of_bounds = bool(size > 0);
            if (MathLib::toLongNumber(counter_init_value) < size)
                condition_out_of_bounds = false;

            parse_for_body(startForScope, arrayInfo, counter_name, condition_out_of_bounds, counter_varid, counter_init_value, counter_init_value);
        }
        return;
    }

    // Get index variable and stopsize.
    bool condition_out_of_bounds = bool(size > 0);
    if (MathLib::toLongNumber(max_counter_value) < size)
        condition_out_of_bounds = false;

    // Goto the end of the condition
    while (tok2 && tok2->str() != ";") {
        if (tok2->str() == "(")
            tok2 = tok2->link();
        else if (tok2->str() == ")")  // unexpected ")" => break
            break;
        tok2 = tok2->next();
    }
    if (!tok2 || tok2->str() != ";")
        return;
    if (!for3(tok2->next(), counter_varid, min_counter_value, max_counter_value, maxMinFlipped))
        return;

    if (Token::Match(tok2->next(), "%var% =|+=|-=") && MathLib::toLongNumber(max_counter_value) <= size)
        condition_out_of_bounds = false;

    // Goto the end parenthesis of the for-statement: "for (x; y; z)" ..
    tok2 = tok->next()->link();
    if (!tok2 || !tok2->tokAt(5)) {
        bailout = true;
        return;
    }

    // Check is the counter variable increased elsewhere inside the loop or used
    // for anything else except reading
    if (for_bailout(tok2->next(), counter_varid)) {
        bailout = true;
        return;
    }

    parse_for_body(tok2->next(), arrayInfo, counter_name, condition_out_of_bounds, counter_varid, min_counter_value, max_counter_value);
}

void CheckBufferOverrun::arrayIndexInForLoop(const Token *tok, const ArrayInfo &arrayInfo)
{
    const MathLib::bigint size = arrayInfo.num(0);
    const Token *tok3 = tok->tokAt(2);
    std::string counter_name;
    unsigned int counter_varid = 0;
    std::string counter_init_value;

    tok3 = for_init(tok3, counter_varid, counter_name, counter_init_value);
    if (tok3 == 0 && !counter_name.empty())
        _tokenizer->getSymbolDatabase()->debugMessage(tok, "for loop variable \'" + counter_name + "\' has varid 0.");
    if (tok3 == 0 || counter_varid == 0)
        return;

    bool maxMinFlipped = false;
    std::string min_counter_value = counter_init_value;
    std::string max_counter_value;
    MathLib::bigint max_value = MathLib::toLongNumber(max_counter_value);

    for_condition(tok3, counter_varid, min_counter_value, max_counter_value, maxMinFlipped);
    while (tok3 && tok3->str() != ";") {
        tok3 = tok3->next();
    }

    for (const Token* tok2 = tok; tok2; tok2 = tok2->next()) {
        if (Token::Match(tok2, "%var% < %num%")) {
            max_value = MathLib::toLongNumber(tok2->strAt(2));
            max_value = max_value - 1;
        }
    }

    if (max_value > size) {
        if (tok3 && tok3->strAt(1) == ")") {
            bool usedInArray = false;
            for (const Token *loopTok = tok3->tokAt(2); loopTok->str() != "}" ; loopTok = loopTok->next()) {
                if (loopTok->varId() == arrayInfo.varid() && loopTok->tokAt(2)->varId() == counter_varid)
                    usedInArray = true;
            }

            for (const Token *loopTok = tok3->tokAt(2); loopTok->str() != "}" ; loopTok = loopTok->next()) {
                if (usedInArray && (counter_varid == loopTok->varId())) {
                    if (loopTok->strAt(1) == "++" ||
                        (loopTok->previous()->type() == Token::eIncDecOp)) {
                        bufferOverrunError(tok, arrayInfo.varname());
                    }
                }
            }
        }
    }
}

void CheckBufferOverrun::checkScope(const Token *tok, const std::vector<std::string> &varname, const ArrayInfo &arrayInfo)
{
    const MathLib::bigint size = arrayInfo.num(0);
    if (size == 0)  // unknown size
        return;

    const MathLib::bigint total_size = arrayInfo.element_size() * arrayInfo.num(0);
    unsigned int varid = arrayInfo.varid();

    std::string varnames;
    for (unsigned int i = 0; i < varname.size(); ++i)
        varnames += (i == 0 ? "" : " . ") + varname[i];

    const unsigned char varc = static_cast<unsigned char>(varname.empty() ? 0U : (varname.size() - 1) * 2U);

    if (tok->str() == "return") {
        tok = tok->next();
        if (!tok)
            return;
    }

    // Array index..
    if ((varid > 0 && Token::Match(tok, "%varid% [ %num% ]", varid)) ||
        (varid == 0 && Token::Match(tok, (varnames + " [ %num% ]").c_str()))) {
        const MathLib::bigint index = MathLib::toLongNumber(tok->strAt(2 + varc));
        if (index >= size) {
            std::vector<MathLib::bigint> indexes;
            indexes.push_back(index);
            arrayIndexOutOfBoundsError(tok->tokAt(varc), arrayInfo, indexes);
        }
    }

    // If the result of pointer arithmetic means that the pointer is
    // out of bounds then this flag will be set.
    bool pointerIsOutOfBounds = false;

    for (const Token* const end = tok->scope()->classEnd; tok != end; tok = tok->next()) {
        if (varid != 0 && Token::Match(tok, "%varid% = new|malloc|realloc", varid)) {
            // Abort
            break;
        }

        // reassign buffer
        if (varid > 0 && Token::Match(tok, "[;{}] %varid% = %any%", varid)) {
            // using varid .. bailout
            if (tok->tokAt(3)->varId() != varid)
                break;
            pointerIsOutOfBounds = false;
        }

        // Array index..
        if ((varid > 0 && ((tok->str() == "return" || (!tok->isName() && !Token::Match(tok, "[.&]"))) && Token::Match(tok->next(), "%varid% [ %num% ]", varid))) ||
            (varid == 0 && ((tok->str() == "return" || (!tok->isName() && !Token::Match(tok, "[.&]"))) && Token::Match(tok->next(), (varnames + " [ %num% ]").c_str())))) {
            std::vector<MathLib::bigint> indexes;
            const Token *tok2 = tok->tokAt(2 + varc);
            for (; Token::Match(tok2, "[ %num% ]"); tok2 = tok2->tokAt(3)) {
                const MathLib::bigint index = MathLib::toLongNumber(tok2->strAt(1));
                indexes.push_back(index);
            }

            if (indexes.size() == arrayInfo.num().size()) {
                // Check if the indexes point outside the whole array..
                // char a[10][10];
                // a[0][20]  <-- ok.
                // a[9][20]  <-- error.

                // total number of elements of array..
                MathLib::bigint totalElements = 1;

                // total index..
                MathLib::bigint totalIndex = 0;

                // calculate the totalElements and totalIndex..
                for (unsigned int i = 0; i < indexes.size(); ++i) {
                    std::size_t ri = indexes.size() - 1 - i;
                    totalIndex += indexes[ri] * totalElements;
                    totalElements *= arrayInfo.num(ri);
                }

                // totalElements == 0 => Unknown size
                if (totalElements == 0)
                    continue;

                const Token *tok3 = tok->previous();
                while (tok3 && Token::Match(tok3->previous(), "%var% ."))
                    tok3 = tok3->tokAt(-2);

                // just taking the address?
                const bool addr(tok3 && (tok3->str() == "&" ||
                                         Token::simpleMatch(tok3->previous(), "& (")));

                // taking address of 1 past end?
                if (addr && totalIndex == totalElements)
                    continue;

                // Is totalIndex in bounds?
                if (totalIndex > totalElements || totalIndex < 0) {
                    arrayIndexOutOfBoundsError(tok->tokAt(1 + varc), arrayInfo, indexes);
                }
                // Is any array index out of bounds?
                else {
                    // check each index for overflow
                    for (unsigned int i = 0; i < indexes.size(); ++i) {
                        if (indexes[i] >= arrayInfo.num(i)) {
                            if (indexes.size() == 1U) {
                                arrayIndexOutOfBoundsError(tok->tokAt(1 + varc), arrayInfo, indexes);
                                break; // only warn about the first one
                            }

                            // The access is still within the memory range for the array
                            // so it may be intentional.
                            else if (_settings->inconclusive) {
                                arrayIndexOutOfBoundsError(tok->tokAt(1 + varc), arrayInfo, indexes);
                                break; // only warn about the first one
                            }
                        }
                    }
                }
            }
            tok = tok2;
            continue;
        }

        // memset, memcmp, memcpy, strncpy, fgets..
        if (varid == 0 && size > 0) {
            std::list<const Token *> callstack;
            callstack.push_back(tok);
            if (Token::Match(tok, ("%var% ( " + varnames + " ,").c_str()))
                checkFunctionParameter(*tok, 1, arrayInfo, callstack);
            if (Token::Match(tok, ("%var% ( %var% , " + varnames + " ,").c_str()))
                checkFunctionParameter(*tok, 2, arrayInfo, callstack);
        }

        // Loop..
        if (Token::simpleMatch(tok, "for (")) {
            const ArrayInfo arrayInfo1(varid, varnames, (unsigned int)size, (unsigned int)total_size);
            bool bailout = false;
            checkScopeForBody(tok, arrayInfo1, bailout);
            if (bailout)
                break;
            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()))) {
            const std::size_t len = Token::getStrLength(tok->tokAt(varc + 4));
            if (total_size > 0 && len >= (unsigned int)total_size) {
                bufferOverrunError(tok, varid > 0 ? std::string("") : varnames);
                continue;
            }
        } else if ((varid > 0 && Token::Match(tok, "strcpy|strcat ( %varid% , %var% )", varid)) ||
                   (varid == 0 && Token::Match(tok, ("strcpy|strcat ( " + varnames + " , %var% )").c_str()))) {
            const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok->tokAt(4)->varId());
            if (var && var->isArray() && var->dimensions().size() == 1) {
                const std::size_t len = (std::size_t)var->dimension(0);
                if (total_size > 0 && len > (unsigned int)total_size) {
                    if (_settings->inconclusive)
                        possibleBufferOverrunError(tok, tok->strAt(4), tok->strAt(2), tok->str() == "strcat");
                    continue;
                }
            }
        }

        // Detect few strcat() calls
        const std::string strcatPattern = varid > 0 ? std::string("strcat ( %varid% , %str% ) ;") : ("strcat ( " + varnames + " , %str% ) ;");
        if (Token::Match(tok, strcatPattern.c_str(), varid)) {
            std::size_t charactersAppend = 0;
            const Token *tok2 = tok;

            while (Token::Match(tok2, strcatPattern.c_str(), varid)) {
                charactersAppend += Token::getStrLength(tok2->tokAt(4 + varc));
                if (charactersAppend >= static_cast<std::size_t>(total_size)) {
                    bufferOverrunError(tok2);
                    break;
                }
                tok2 = tok2->tokAt(7 + varc);
            }
        }

        // sprintf..
        // TODO: change total_size to an unsigned value and remove the "&& total_size > 0" check.
        const std::string sprintfPattern = varid > 0 ? std::string("sprintf ( %varid% , %str% [,)]") : ("sprintf ( " + varnames + " , %str% [,)]");
        if (Token::Match(tok, sprintfPattern.c_str(), varid) && total_size > 0) {
            checkSprintfCall(tok, static_cast<unsigned int>(total_size));
        }

        // snprintf..
        const std::string snprintfPattern = varid > 0 ? std::string("snprintf ( %varid% , %num% ,") : ("snprintf ( " + varnames + " , %num% ,");
        if (Token::Match(tok, snprintfPattern.c_str(), varid)) {
            const MathLib::bigint n = MathLib::toLongNumber(tok->strAt(4 + varc));
            if (n > total_size)
                outOfBoundsError(tok->tokAt(4 + varc), "snprintf size", true, n, total_size);
        }

        // Check function call..
        if (Token::Match(tok, "%var% (") && total_size > 0) {
            // No varid => function calls are not handled
            if (varid == 0)
                continue;

            const ArrayInfo arrayInfo1(varid, varnames, total_size / size, size);
            const std::list<const Token *> callstack;
            checkFunctionCall(tok, arrayInfo1, callstack);
        }

        // undefined behaviour: result of pointer arithmetic is out of bounds
        else if (varid && Token::Match(tok, "= %varid% + %num% ;", varid)) {
            const MathLib::bigint index = MathLib::toLongNumber(tok->strAt(3));
            if (index > size && _settings->isEnabled("portability"))
                pointerOutOfBoundsError(tok->next(), "buffer");
            if (index >= size && Token::Match(tok->tokAt(-2), "[;{}] %varid% =", varid))
                pointerIsOutOfBounds = true;
        }

        else if (pointerIsOutOfBounds && Token::Match(tok, "[;{}=] * %varid% [;=]", varid)) {
            outOfBoundsError(tok->tokAt(2), tok->strAt(2), false, 0, 0);
        }
    }
}


void CheckBufferOverrun::checkScope(const Token *tok, const ArrayInfo &arrayInfo)
{
    const MathLib::bigint total_size = arrayInfo.num(0) * arrayInfo.element_size();

    const Token *scope_begin = tok->previous();
    assert(scope_begin != 0);

    for (const Token* const end = tok->scope()->classEnd; tok != end; tok = tok->next()) {
        // Skip array declarations
        if (Token::Match(tok, "[;{}] %type% *| %var% [") && tok->strAt(1) != "return") {
            tok = tok->tokAt(3);
            continue;
        }

        else if (Token::Match(tok, "%varid% [ %num% ]", arrayInfo.varid())) {
            std::vector<MathLib::bigint> indexes;
            for (const Token *tok2 = tok->next(); Token::Match(tok2, "[ %num% ]"); tok2 = tok2->tokAt(3)) {
                const MathLib::bigint index = MathLib::toLongNumber(tok2->strAt(1));
                if (index < 0) {
                    indexes.clear();
                    break;
                }
                indexes.push_back(index);
            }
            if (indexes.size() == arrayInfo.num().size()) {
                // Check if the indexes point outside the whole array..
                // char a[10][10];
                // a[0][20]  <-- ok.
                // a[9][20]  <-- error.

                // total number of elements of array..
                MathLib::bigint totalElements = 1;

                // total index..
                MathLib::bigint totalIndex = 0;

                // calculate the totalElements and totalIndex..
                for (unsigned int i = 0; i < indexes.size(); ++i) {
                    std::size_t ri = indexes.size() - 1 - i;
                    totalIndex += indexes[ri] * totalElements;
                    totalElements *= arrayInfo.num(ri);
                }

                // totalElements == 0 => Unknown size
                if (totalElements == 0)
                    continue;

                const Token *tok2 = tok->previous();
                while (tok2 && Token::Match(tok2->previous(), "%var% ."))
                    tok2 = tok2->tokAt(-2);

                // just taking the address?
                const bool addr(tok2 && (tok2->str() == "&" ||
                                         Token::simpleMatch(tok2->previous(), "& (")));

                // taking address of 1 past end?
                if (addr && totalIndex == totalElements)
                    continue;

                // Is totalIndex in bounds?
                if (totalIndex >= totalElements) {
                    arrayIndexOutOfBoundsError(tok, arrayInfo, indexes);
                }
                // Is any array index out of bounds?
                else {
                    // check each index for overflow
                    for (unsigned int i = 0; i < indexes.size(); ++i) {
                        if (indexes[i] >= arrayInfo.num(i)) {
                            // The access is still within the memory range for the array
                            // so it may be intentional.
                            if (_settings->inconclusive) {
                                arrayIndexOutOfBoundsError(tok, arrayInfo, indexes);
                                break; // only warn about the first one
                            }
                        }
                    }
                }
            }
        }

        // Loop..
        else if (Token::simpleMatch(tok, "for (")) {
            bool bailout = false;
            arrayIndexInForLoop(tok, arrayInfo);
            checkScopeForBody(tok, arrayInfo, bailout);
            if (bailout)
                break;
            continue;
        }


        // Check function call..
        if (Token::Match(tok, "%var% (")) {
            const std::list<const Token *> callstack;
            checkFunctionCall(tok, arrayInfo, callstack);
        }

        if (Token::Match(tok, "strncpy|memcpy|memmove ( %varid% , %str% , %num% )", arrayInfo.varid())) {
            unsigned int num = (unsigned int)MathLib::toLongNumber(tok->strAt(6));
            if (Token::getStrLength(tok->tokAt(4)) >= (unsigned int)total_size && (unsigned int)total_size == num) {
                if (_settings->inconclusive)
                    bufferNotZeroTerminatedError(tok, tok->strAt(2), tok->str());
            }
        }

        if ((Token::Match(tok, "strncpy|strncat ( %varid% , %var%", arrayInfo.varid()) && Token::Match(tok->linkAt(1)->tokAt(-2), ", %num% )"))) {
            const Token* param3 = tok->linkAt(1)->previous();

            // check for strncpy which is not terminated
            if (tok->str() == "strncpy") {
                // strncpy takes entire variable length as input size
                unsigned int num = (unsigned int)MathLib::toLongNumber(param3->str());

                // this is currently 'inconclusive'. See TestBufferOverrun::terminateStrncpy3
                if (num >= total_size && _settings->isEnabled("style") && _settings->inconclusive) {
                    const Token *tok2 = tok->next()->link()->next();
                    for (; tok2; tok2 = tok2->next()) {
                        if (tok2->varId() == tok->tokAt(2)->varId()) {
                            if (!Token::Match(tok2, "%varid% [ %any% ]  = 0 ;", tok->tokAt(2)->varId())) {
                                terminateStrncpyError(tok, tok->strAt(2));
                            }

                            break;
                        }
                    }
                }
            }

            // Dangerous usage of strncat..
            else if (tok->str() == "strncat") {
                const MathLib::bigint n = MathLib::toLongNumber(param3->str());
                if (n >= total_size)
                    strncatUsageError(tok);
            }

            // Dangerous usage of strncpy + strncat..
            if (Token::Match(param3->tokAt(2), "; strncat ( %varid% ,", arrayInfo.varid()) && Token::Match(param3->linkAt(4)->tokAt(-2), ", %num% )")) {
                const MathLib::bigint n = MathLib::toLongNumber(param3->str()) + MathLib::toLongNumber(param3->linkAt(4)->strAt(-1));
                if (n > total_size)
                    strncatUsageError(param3->tokAt(3));
            }
        }

        // Writing data into array..
        if (Token::Match(tok, "strcpy|strcat ( %varid% , %str% )", arrayInfo.varid())) {
            const std::size_t len = Token::getStrLength(tok->tokAt(4));
            if (total_size > 0 && len >= (unsigned int)total_size) {
                bufferOverrunError(tok, arrayInfo.varname());
                continue;
            }
        }

        // Detect few strcat() calls
        if (total_size > 0 && Token::Match(tok, "strcat ( %varid% , %str% ) ;", arrayInfo.varid())) {
            std::size_t charactersAppend = 0;
            const Token *tok2 = tok;

            while (tok2 && Token::Match(tok2, "strcat ( %varid% , %str% ) ;", arrayInfo.varid())) {
                charactersAppend += Token::getStrLength(tok2->tokAt(4));
                if (charactersAppend >= (unsigned int)total_size) {
                    bufferOverrunError(tok2, arrayInfo.varname());
                    break;
                }
                tok2 = tok2->tokAt(7);
            }
        }


        if (Token::Match(tok, "sprintf ( %varid% , %str% [,)]", arrayInfo.varid())) {
            checkSprintfCall(tok, total_size);
        }

        // snprintf..
        if (total_size > 0 && Token::Match(tok, "snprintf ( %varid% , %num% ,", arrayInfo.varid())) {
            const MathLib::bigint n = MathLib::toLongNumber(tok->strAt(4));
            if (n > total_size)
                outOfBoundsError(tok->tokAt(4), "snprintf size", true, n, total_size);
        }

        // readlink() / readlinkat() buffer usage
        if (_settings->standards.posix) {
            if (Token::simpleMatch(tok, "readlink (") && Token::Match(tok->tokAt(2)->nextArgument(), "%varid% , %num% )", arrayInfo.varid()))
                checkReadlinkBufferUsage(tok, scope_begin, total_size, false);
            else if (Token::simpleMatch(tok, "readlinkat (") && Token::Match(tok->tokAt(2)->nextArgument()->nextArgument(), "%varid% , %num% )", arrayInfo.varid()))
                checkReadlinkBufferUsage(tok, scope_begin, total_size, true);
        }

        // undefined behaviour: result of pointer arithmetic is out of bounds
        if (_settings->isEnabled("portability") && Token::Match(tok, "= %varid% + %num% ;", arrayInfo.varid())) {
            const MathLib::bigint index = MathLib::toLongNumber(tok->strAt(3));
            if (index < 0 || index > arrayInfo.num(0)) {
                pointerOutOfBoundsError(tok->next(), "array");
            }
        }
    }
}

void CheckBufferOverrun::checkReadlinkBufferUsage(const Token* tok, const Token *scope_begin, const MathLib::bigint total_size, const bool is_readlinkat)
{
    const Token* bufParam = tok->tokAt(2)->nextArgument();
    if (is_readlinkat)
        bufParam = bufParam->nextArgument();
    const std::string funcname = is_readlinkat ? "readlinkat" : "readlink";

    const MathLib::bigint n = MathLib::toLongNumber(bufParam->strAt(2));
    if (total_size > 0 && n > total_size)
        outOfBoundsError(bufParam, funcname + "() buf size", true, n, total_size);

    if (!_settings->inconclusive)
        return;

    // readlink()/readlinkat() never terminates the buffer, check the end of the scope for buffer termination.
    bool found_termination = false;
    const Token *scope_end = scope_begin->link();
    for (const Token *tok2 = bufParam->tokAt(4); tok2 && tok2 != scope_end; tok2 = tok2->next()) {
        if (Token::Match(tok2, "%varid% [ %any% ] = 0 ;", bufParam->varId())) {
            found_termination = true;
            break;
        }
    }

    if (!found_termination) {
        bufferNotZeroTerminatedError(tok, bufParam->str(), funcname);
    } else if (n == total_size) {
        possibleReadlinkBufferOverrunError(tok, funcname, bufParam->str());
    }
}

//---------------------------------------------------------------------------
// Checking local variables in a scope
//---------------------------------------------------------------------------

void CheckBufferOverrun::checkGlobalAndLocalVariable()
{
    // check string literals
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        if (Token::Match(tok, "%str% [ %num% ]")) {
            std::string str = tok->strValue();
            std::size_t index = (std::size_t)std::atoi(tok->strAt(2).c_str());
            if (index > str.length()) {
                bufferOverrunError(tok, tok->str());
            }
        }
    }

    // check all known fixed size arrays first by just looking them up
    const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
    for (unsigned int i = 1; i <= _tokenizer->varIdCount(); i++) {
        const Variable *var = symbolDatabase->getVariableFromVarId(i);
        if (var && var->isArray() && var->dimension(0) > 0) {
            const ArrayInfo arrayInfo(var, _tokenizer);
            const Token *tok = var->nameToken();
            while (tok && tok->str() != ";") {
                if (tok->str() == "{") {
                    if (Token::simpleMatch(tok->previous(), "= {"))
                        tok = tok->link();
                    else
                        break;
                }
                tok = tok->next();
            }
            if (!tok)
                break;
            if (tok->str() == "{")
                tok = tok->next();
            checkScope(tok, arrayInfo);
        }
    }

    // find all dynamically allocated arrays next
    const std::size_t functions = symbolDatabase->functionScopes.size();
    for (std::size_t i = 0; i < functions; ++i) {
        const Scope * scope = symbolDatabase->functionScopes[i];

        for (const Token *tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
            // if the previous token exists, it must be either a variable name or "[;{}]"
            if (tok->previous() && (!tok->previous()->isName() && !Token::Match(tok->previous(), "[;{}]")))
                continue;

            // size : Max array index
            MathLib::bigint size = 0;

            // type : The type of a array element
            std::string type;

            // varid : The variable id for the array
            unsigned int varid = 0;

            // nextTok : number of tokens used in variable declaration - used to skip to next statement.
            int nextTok = 0;

            _errorLogger->reportProgress(_tokenizer->getSourceFilePath(),
                                         "Check (BufferOverrun::checkGlobalAndLocalVariable)",
                                         tok->progressValue());

            if (Token::Match(tok, "[*;{}] %var% = new %type% [ %num% ]")) {
                size = MathLib::toLongNumber(tok->strAt(6));
                type = tok->strAt(4);
                varid = tok->next()->varId();
                nextTok = 8;
            } else if (Token::Match(tok, "[*;{}] %var% = new %type% ( %num% )")) {
                size = 1;
                type = tok->strAt(4);
                varid = tok->next()->varId();
                nextTok = 8;
            } else if (Token::Match(tok, "[;{}] %var% = %str% ;") &&
                       tok->next()->varId() > 0 &&
                       NULL != Token::findmatch(_tokenizer->tokens(), "[;{}] const| %type% * %varid% ;", tok->next()->varId())) {
                size = 1 + int(tok->tokAt(3)->strValue().size());
                type = "char";
                varid = tok->next()->varId();
                nextTok = 4;
            } else if (Token::Match(tok, "[*;{}] %var% = malloc|alloca ( %num% ) ;")) {
                size = MathLib::toLongNumber(tok->strAt(5));
                type = "char";   // minimum type, typesize=1
                varid = tok->next()->varId();
                nextTok = 7;

                if (varid > 0) {
                    // get type of variable
                    const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(varid);
                    /** @todo false negatives: this may be too conservative */
                    if (!var || var->typeEndToken()->str() != "*" || var->typeStartToken()->next() != var->typeEndToken())
                        continue;

                    // get name of variable
                    type = var->typeStartToken()->str();

                    // malloc() gets count of bytes and not count of
                    // elements, so we should calculate count of elements
                    // manually
                    unsigned int sizeOfType = _tokenizer->sizeOfType(var->typeStartToken());
                    if (sizeOfType > 0)
                        size /= static_cast<int>(sizeOfType);
                }
            } else {
                continue;
            }

            if (varid == 0)
                continue;

            Token sizeTok(0);
            sizeTok.str(type);
            const MathLib::bigint total_size = size * static_cast<int>(_tokenizer->sizeOfType(&sizeTok));
            if (total_size == 0)
                continue;

            std::vector<std::string> v;
            ArrayInfo temp(varid, tok->next()->str(), total_size / size, size);
            checkScope(tok->tokAt(nextTok), v, temp);
        }
    }
}
//---------------------------------------------------------------------------


//---------------------------------------------------------------------------
// Checking member variables of structs..
//---------------------------------------------------------------------------

void CheckBufferOverrun::checkStructVariable()
{
    const SymbolDatabase * symbolDatabase = _tokenizer->getSymbolDatabase();

    // find every class and struct
    const std::size_t classes = symbolDatabase->classAndStructScopes.size();
    for (std::size_t i = 0; i < classes; ++i) {
        const Scope * scope = symbolDatabase->classAndStructScopes[i];

        // check all variables to see if they are arrays
        std::list<Variable>::const_iterator var;
        for (var = scope->varlist.begin(); var != scope->varlist.end(); ++var) {
            // find all array variables
            if (var->isArray()) {
                // create ArrayInfo from the array variable
                ArrayInfo arrayInfo(&*var, _tokenizer);

                // find every function
                const std::size_t functions = symbolDatabase->functionScopes.size();
                for (std::size_t j = 0; j < functions; ++j) {
                    const Scope * func_scope = symbolDatabase->functionScopes[j];

                    // If struct is declared in a function then check
                    // if scope_func matches
                    if (scope->nestedIn->type == Scope::eFunction &&
                        scope->nestedIn != &*func_scope) {
                        continue;
                    }

                    // check for member variables
                    if (func_scope->functionOf == &*scope) {
                        // only check non-empty function
                        if (func_scope->classStart->next() != func_scope->classEnd) {
                            // start checking after the {
                            const Token *tok = func_scope->classStart->next();
                            checkScope(tok, arrayInfo);
                        }
                    }

                    // skip inner scopes..
                    /** @todo false negatives: handle inner scopes someday */
                    if (scope->nestedIn->isClassOrStruct())
                        continue;

                    std::vector<std::string> varname;
                    varname.push_back("");
                    varname.push_back(arrayInfo.varname());

                    // search the function and it's parameters
                    for (const Token *tok3 = func_scope->classDef; tok3 && tok3 != func_scope->classEnd; tok3 = tok3->next()) {
                        // search for the class/struct name
                        if (tok3->str() != scope->className)
                            continue;

                        // Declare variable: Fred fred1;
                        if (Token::Match(tok3->next(), "%var% ;"))
                            varname[0] = tok3->strAt(1);

                        // Declare pointer or reference: Fred *fred1
                        else if (Token::Match(tok3->next(), "*|& %var% [,);=]"))
                            varname[0] = tok3->strAt(2);

                        else
                            continue;

                        // check for variable sized structure
                        if (scope->type == Scope::eStruct && var->isPublic()) {
                            // last member of a struct with array size of 0 or 1 could be a variable sized structure
                            if (var->dimensions().size() == 1 && var->dimension(0) < 2 &&
                                var->index() == (scope->varlist.size() - 1)) {
                                // dynamically allocated so could be variable sized structure
                                if (tok3->next()->str() == "*") {
                                    // check for allocation
                                    if ((Token::Match(tok3->tokAt(3), "; %var% = malloc ( %num% ) ;") ||
                                         (Token::Match(tok3->tokAt(3), "; %var% = (") &&
                                          Token::Match(tok3->linkAt(6), ") malloc ( %num% ) ;"))) &&
                                        (tok3->strAt(4) == tok3->strAt(2))) {
                                        MathLib::bigint size;

                                        // find size of allocation
                                        if (tok3->strAt(3) == "(") // has cast
                                            size = MathLib::toLongNumber(tok3->linkAt(6)->strAt(3));
                                        else
                                            size = MathLib::toLongNumber(tok3->strAt(8));

                                        // We don't calculate the size of a structure even when we know
                                        // the size of the members.  We just assign a length of 100 for
                                        // any struct.  If the size is less than 100, we assume the
                                        // programmer knew the size and specified it rather than using
                                        // sizeof(struct). If the size is greater than 100, we assume
                                        // the programmer specified the size as sizeof(struct) + number.
                                        // Either way, this is just a guess and could be wrong.  The
                                        // information to make the right decision has been simplified
                                        // away by the time we get here.
                                        if (size != 100) { // magic number for size of struct
                                            // check if a real size was specified and give up
                                            // malloc(10) rather than malloc(sizeof(struct))
                                            if (size < 100)
                                                continue;

                                            // calculate real array size based on allocated size
                                            MathLib::bigint elements = (size - 100) / arrayInfo.element_size();
                                            arrayInfo.num(0, arrayInfo.num(0) + elements);
                                        }
                                    }

                                    // size unknown so assume it is a variable sized structure
                                    else
                                        continue;
                                }
                            }
                        }

                        // Goto end of statement.
                        const Token *CheckTok = NULL;
                        while (tok3 && tok3 != func_scope->classEnd) {
                            // 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..
                        ArrayInfo temp = arrayInfo;
                        temp.varid(0); // do variable lookup by variable and member names rather than varid
                        std::string varnames; // use class and member name for messages
                        for (unsigned int k = 0; k < varname.size(); ++k)
                            varnames += (k == 0 ? "" : ".") + varname[k];
                        temp.varname(varnames);
                        checkScope(CheckTok, varname, temp);
                    }
                }
            }
        }
    }
}
//---------------------------------------------------------------------------

void CheckBufferOverrun::bufferOverrun()
{
    checkGlobalAndLocalVariable();
    checkStructVariable();
    checkBufferAllocatedWithStrlen();
    checkInsecureCmdLineArgs();
}
//---------------------------------------------------------------------------


MathLib::bigint CheckBufferOverrun::countSprintfLength(const std::string &input_string, const std::list<const Token*> &parameters)
{
    bool percentCharFound = false;
    std::size_t 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();
    std::size_t 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)->type() != Token::eString)
                    parameterLength = (*paramIter)->str().length();

                handleNextParameter = true;
                break;
            case 's':
                if (paramIter != parameters.end() && *paramIter && (*paramIter)->type() == Token::eString)
                    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 = static_cast<unsigned int>(std::abs(std::atoi(digits_string.c_str())));
            if (i_d_x_f_found)
                tempDigits = std::max(static_cast<unsigned int>(tempDigits), 1U);

            if (digits_string.find('.') != std::string::npos) {
                const std::string endStr = digits_string.substr(digits_string.find('.') + 1);
                unsigned int maxLen = std::max(static_cast<unsigned int>(std::abs(std::atoi(endStr.c_str()))), 1U);

                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 (MathLib::bigint)input_string_size;
}

void CheckBufferOverrun::checkSprintfCall(const Token *tok, const MathLib::bigint size)
{
    if (size == 0)
        return;

    std::list<const Token*> parameters;
    const Token* vaArg = tok->tokAt(2)->nextArgument()->nextArgument();
    while (vaArg) {
        if (Token::Match(vaArg->next(), "[,)]")) {
            if (vaArg->type() == Token::eString)
                parameters.push_back(vaArg);

            else if (vaArg->isNumber())
                parameters.push_back(vaArg);

            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);

        vaArg = vaArg->nextArgument();
    }

    MathLib::bigint len = countSprintfLength(tok->tokAt(2)->nextArgument()->strValue(), parameters);
    if (len > size) {
        bufferOverrunError(tok);
    }
}



//---------------------------------------------------------------------------
// Checking for allocating insufficient memory for copying a string by
// allocating only strlen(src) bytes instead of strlen(src) + 1 bytes (one
// extra for the terminating null character).
// Example:
//   char *b = malloc(strlen(a));   // Should be malloc(strlen(a) + 1);
//   strcpy(b, a);                  // <== Buffer overrun
//---------------------------------------------------------------------------
void CheckBufferOverrun::checkBufferAllocatedWithStrlen()
{
    const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();

    const std::size_t functions = symbolDatabase->functionScopes.size();
    for (std::size_t i = 0; i < functions; ++i) {
        const Scope * scope = symbolDatabase->functionScopes[i];
        for (const Token *tok = scope->classStart->next(); tok && tok != scope->classEnd; tok = tok->next()) {
            unsigned int dstVarId;
            unsigned int srcVarId;

            // Look for allocation of a buffer based on the size of a string
            if (Token::Match(tok, "%var% = malloc|g_malloc|g_try_malloc ( strlen ( %var% ) )")) {
                dstVarId = tok->varId();
                srcVarId = tok->tokAt(6)->varId();
                tok      = tok->tokAt(8);
            } else if (Token::Match(tok, "%var% = new char [ strlen ( %var% ) ]")) {
                dstVarId = tok->varId();
                srcVarId = tok->tokAt(7)->varId();
                tok      = tok->tokAt(9);
            } else if (Token::Match(tok, "%var% = realloc|g_realloc|g_try_realloc ( %var% , strlen ( %var% ) )")) {
                dstVarId = tok->varId();
                srcVarId = tok->tokAt(8)->varId();
                tok      = tok->tokAt(10);
            } else
                continue;

            // To avoid false positives and added complexity, we will only look for
            // improper usage of the buffer within the block that it was allocated
            for (const Token* const end = tok->scope()->classEnd; tok && tok->next() && tok != end; tok = tok->next()) {
                // If the buffers are modified, we can't be sure of their sizes
                if (tok->varId() == srcVarId || tok->varId() == dstVarId)
                    break;

                if (Token::Match(tok, "strcpy ( %varid% , %var% )", dstVarId) &&
                    tok->tokAt(4)->varId() == srcVarId) {
                    bufferOverrunError(tok);
                } else if (Token::Match(tok, "sprintf ( %varid% , %str% , %var% )", dstVarId) &&
                           tok->tokAt(6)->varId() == srcVarId &&
                           tok->strAt(4).find("%s") != std::string::npos) {
                    bufferOverrunError(tok);
                }
            }
            if (!tok)
                return;
        }
    }
}

//---------------------------------------------------------------------------
// Checking for buffer overflow caused by copying command line arguments
// into fixed-sized buffers without checking to make sure that the command
// line arguments will not overflow the buffer.
//
// int main(int argc, char* argv[])
// {
//   char prog[10];
//   strcpy(prog, argv[0]);      <-- Possible buffer overrun
// }
//---------------------------------------------------------------------------
void CheckBufferOverrun::checkInsecureCmdLineArgs()
{
    const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();

    std::size_t functions = symbolDatabase->functionScopes.size();
    for (std::size_t i = 0; i < functions; ++i) {
        const Scope * scope = symbolDatabase->functionScopes[i];
        Function * j = scope->function;
        if (j) {
            const Token* tok = j->token;

            // Get the name of the argv variable
            unsigned int varid = 0;
            if (Token::Match(tok, "main ( int %var% , char * %var% [ ] ,|)")) {
                varid = tok->tokAt(7)->varId();

            } else if (Token::Match(tok, "main ( int %var% , char * * %var% ,|)")) {
                varid = tok->tokAt(8)->varId();
            }
            if (varid == 0)
                continue;

            // Jump to the opening curly brace
            tok = tok->next()->link();
            if (!Token::simpleMatch(tok, ") {"))
                continue;
            tok = tok->next();

            // Search within main() for possible buffer overruns involving argv
            for (const Token* end = tok->link(); tok != end; tok = tok->next()) {
                // If argv is modified or tested, its size may be being limited properly
                if (tok->varId() == varid)
                    break;

                // Match common patterns that can result in a buffer overrun
                // e.g. strcpy(buffer, argv[0])
                if (Token::Match(tok, "strcpy|strcat ( %var% , * %varid%", varid) ||
                    Token::Match(tok, "strcpy|strcat ( %var% , %varid% [", varid)) {
                    cmdLineArgsError(tok);
                } else if (Token::Match(tok, "sprintf ( %var% , %str% , %varid% [", varid) &&
                           tok->strAt(4).find("%s") != std::string::npos) {
                    cmdLineArgsError(tok);
                } else if (Token::Match(tok, "sprintf ( %var% , %str% , * %varid%", varid) &&
                           tok->strAt(4).find("%s") != std::string::npos) {
                    cmdLineArgsError(tok);
                }
            }
        }
    }
}
//---------------------------------------------------------------------------


void CheckBufferOverrun::negativeIndexError(const Token *tok, MathLib::bigint index)
{
    std::ostringstream ostr;
    ostr << "Array index " << index << " is out of bounds.";
    reportError(tok, Severity::error, "negativeIndex", ostr.str());
}

void CheckBufferOverrun::negativeIndex()
{
    const char pattern[] = "[ %num% ]";
    for (const Token *tok = Token::findmatch(_tokenizer->tokens(), pattern); tok; tok = Token::findmatch(tok->next(),pattern)) {
        const MathLib::bigint index = MathLib::toLongNumber(tok->next()->str());
        if (index < 0) {
            // Negative index. Check if it's an array.
            const Token *tok2 = tok;
            while (tok2->strAt(-1) == "]")
                tok2 = tok2->previous()->link();

            if (tok2->previous() && tok2->previous()->varId()) {
                const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok2->previous()->varId());
                if (var && var->isArray())
                    negativeIndexError(tok, index);
            }
        }
    }
}




#include "executionpath.h"

/// @addtogroup Checks
/// @{



CheckBufferOverrun::ArrayInfo::ArrayInfo()
    : _element_size(0), _varid(0)
{
}

CheckBufferOverrun::ArrayInfo::ArrayInfo(const CheckBufferOverrun::ArrayInfo &ai)
{
    *this = ai;
}

CheckBufferOverrun::ArrayInfo::ArrayInfo(const Variable *var, const Tokenizer *tokenizer)
    : _varname(var->name()), _varid(var->varId())
{
    for (std::size_t i = 0; i < var->dimensions().size(); i++)
        _num.push_back(var->dimension(i));
    if (var->typeEndToken()->str() == "*")
        _element_size = tokenizer->sizeOfType(var->typeEndToken());
    else if (var->typeStartToken()->str() == "struct")
        _element_size = 100;
    else
        _element_size = tokenizer->sizeOfType(var->typeEndToken());
}

CheckBufferOverrun::ArrayInfo & CheckBufferOverrun::ArrayInfo::operator=(const CheckBufferOverrun::ArrayInfo &ai)
{
    if (&ai != this) {
        _element_size = ai._element_size;
        _num = ai._num;
        _varid = ai._varid;
        _varname = ai._varname;
    }
    return *this;
}

/**
 * Create array info with specified data
 * The intention is that this is only a temporary solution.. all
 * checking should be based on ArrayInfo from the start and then
 * this will not be needed as the declare can be used instead.
 */
CheckBufferOverrun::ArrayInfo::ArrayInfo(unsigned int id, const std::string &name, MathLib::bigint size1, MathLib::bigint n)
    : _varname(name), _element_size(size1), _varid(id)
{
    _num.push_back(n);
}

CheckBufferOverrun::ArrayInfo CheckBufferOverrun::ArrayInfo::limit(MathLib::bigint value) const
{
    MathLib::bigint uvalue = std::max(MathLib::bigint(0), value);
    MathLib::bigint n = 1;
    for (unsigned int i = 0; i < _num.size(); ++i)
        n *= _num[i];
    if (uvalue > n)
        n = uvalue;
    return ArrayInfo(_varid, _varname, _element_size, n - uvalue);
}


/**
 * @brief %Check for buffer overruns (using ExecutionPath)
 */

class ExecutionPathBufferOverrun : public ExecutionPath {
public:
    /** Startup constructor */
    ExecutionPathBufferOverrun(Check *c, const std::map<unsigned int, CheckBufferOverrun::ArrayInfo> &arrayinfo)
        : ExecutionPath(c, 0), arrayInfo(arrayinfo), value(0) {
    }

private:
    /** @brief Copy this check. Called from the ExecutionPath baseclass. */
    ExecutionPath *copy() {
        return new ExecutionPathBufferOverrun(*this);
    }

    /** @brief is other execution path equal? */
    bool is_equal(const ExecutionPath *e) const {
        const ExecutionPathBufferOverrun *c = static_cast<const ExecutionPathBufferOverrun *>(e);
        return (value == c->value);
    }

    /** @brief Buffer information */
    const std::map<unsigned int, CheckBufferOverrun::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, CheckBufferOverrun::ArrayInfo> &arrayinfo, unsigned int varid_)
        : ExecutionPath(c, varid_),
          arrayInfo(arrayinfo),
          value(0) { // Pretend that variables are initialized to 0. This checking is not about uninitialized variables.
    }

    /** @brief Variable value. */
    MathLib::bigint value;

    /**
     * @brief Assign value to a variable
     * @param checks the execution paths
     * @param varid the variable id
     * @param value the assigned value
     */
    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, analyse the array usage
     * @param tok token where usage occurs (only used when reporting the error)
     * @param checks The execution paths
     * @param varid1 variable id for the array
     * @param varid2 variable id for the index
     */
    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
        ExecutionPathBufferOverrun *c = dynamic_cast<ExecutionPathBufferOverrun *>(checks.front());
        std::map<unsigned int, CheckBufferOverrun::ArrayInfo>::const_iterator it1;
        it1 = c->arrayInfo.find(varid1);
        if (it1 == c->arrayInfo.end())
            return;
        const CheckBufferOverrun::ArrayInfo& ai = it1->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) {
            c = dynamic_cast<ExecutionPathBufferOverrun *>(*it);
            if (c && c->varId == varid2 && c->value >= ai.num(0)) {
                // variable value is out of bounds, report error
                CheckBufferOverrun *checkBufferOverrun = dynamic_cast<CheckBufferOverrun *>(c->owner);
                if (checkBufferOverrun) {
                    std::vector<MathLib::bigint> index;
                    index.push_back(c->value);
                    checkBufferOverrun->arrayIndexOutOfBoundsError(tok, ai, index);
                    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() || isC)*/) {
                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;
        }

        // Assign variable (unknown value = 0)..
        if (Token::Match(tok.tokAt(-2), "(|, & %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 variables and extract array info..
    std::map<unsigned int, ArrayInfo> arrayInfo;
    for (unsigned int i = 1; i <= _tokenizer->varIdCount(); i++) {
        const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(i);
        if (var && var->isArray() && var->dimension(0) > 0)
            arrayInfo[i] = ArrayInfo(var, _tokenizer);
    }

    // Perform checking - check how the arrayInfo arrays are used
    ExecutionPathBufferOverrun c(this, arrayInfo);
    checkExecutionPaths(_tokenizer->getSymbolDatabase(), &c);
}




void CheckBufferOverrun::arrayIndexThenCheck()
{
    if (!_settings->isEnabled("style"))
        return;

    const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
    const std::size_t functions = symbolDatabase->functionScopes.size();
    for (std::size_t i = 0; i < functions; ++i) {
        const Scope * scope = symbolDatabase->functionScopes[i];
        for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
            if (Token::Match(tok, "%var% [ %var% ]")) {
                const std::string& indexName(tok->strAt(2));

                // skip array index..
                tok = tok->tokAt(4);
                while (tok && tok->str() == "[")
                    tok = tok->link()->next();

                // syntax error
                if (!tok)
                    return;

                // skip comparison
                if (tok->type() == Token::eComparisonOp && tok->strAt(2) == "&&")
                    tok = tok->tokAt(2);

                // check if array index is ok
                if (Token::Match(tok, ("&& " + indexName + " <|<=").c_str()))
                    arrayIndexThenCheckError(tok, indexName);
            }
        }
    }
}

void CheckBufferOverrun::arrayIndexThenCheckError(const Token *tok, const std::string &indexName)
{
    reportError(tok, Severity::style, "arrayIndexThenCheck",
                "Array index '" + indexName + "' is used before limits check.\n"
                "Defensive programming: The variable '" + indexName + "' is used as an array index before it "
                "is check that is within limits. This can mean that the array might be accessed out of bounds. "
                "Reorder conditions such as '(a[i] && i < 10)' to '(i < 10 && a[i])'. That way the array will "
                "not be accessed if the index is out of limits.");
}