cppcheck/lib/checkbufferoverrun.cpp

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2014 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 "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 (std::size_t 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 (std::size_t 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 Token *tok, const ArrayInfo &arrayInfo, const std::vector<ValueFlow::Value> &index)
{
    std::ostringstream errmsg;

    errmsg << "Array '" << arrayInfo.varname();
    for (std::size_t i = 0; i < arrayInfo.num().size(); ++i)
        errmsg << "[" << arrayInfo.num(i) << "]";
    if (index.size() == 1)
        errmsg << "' accessed at index " << index[0].intvalue << ", which is out of bounds.";
    else {
        errmsg << "' index " << arrayInfo.varname();
        for (std::size_t i = 0; i < index.size(); ++i)
            errmsg << "[" << index[i].intvalue << "]";
        errmsg << " out of bounds.";
    }

    const Token *condition = nullptr;
    for (std::size_t i = 0; i < index.size(); ++i) {
        if (condition == nullptr)
            condition = index[i].condition;
    }

    if (condition != nullptr) {
        errmsg << " Otherwise condition '" << condition->expressionString() << "' is redundant.";
        std::list<const Token *> callstack;
        callstack.push_back(tok);
        callstack.push_back(condition);
        reportError(callstack, Severity::warning, "arrayIndexOutOfBoundsCond", errmsg.str());
    } else {
        reportError(tok, Severity::error, "arrayIndexOutOfBounds", errmsg.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("warning"))
        return;

    reportError(tok, Severity::warning, "strncatUsage",
                "Dangerous usage of strncat - 3rd parameter is the maximum number of characters to append.\n"
                "At most, strncat appends the 3rd parameter's amount of characters and adds a terminating null byte.\n"
                "The safe way to use strncat is to subtract one from the remaining space in the buffer and use it as 3rd parameter."
                "Source: http://www.cplusplus.com/reference/cstring/strncat/\n"
                "Source: http://www.opensource.apple.com/source/Libc/Libc-167/gen.subproj/i386.subproj/strncat.c");
}

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("warning"))
        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);
}

void CheckBufferOverrun::argumentSizeError(const Token *tok, const std::string &functionName, const std::string &varname)
{
    reportError(tok, Severity::warning, "argumentSize", "The array '" + varname + "' is too small, the function '" + functionName + "' expects a bigger one.");
}

void CheckBufferOverrun::negativeMemoryAllocationSizeError(const Token *tok)
{
    reportError(tok, Severity::error, "negativeMemoryAllocationSize",
                "Memory allocation size is negative.\n"
                "Memory allocation size is negative."
                "Negative allocation size has no specified behaviour.");
}

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


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


/**
 * 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)
{
    const Token* end = tok->linkAt(1)->linkAt(1);
    if (Token::simpleMatch(end, "} else {")) // scan the else-block
        end = end->linkAt(2);
    if (Token::simpleMatch(end, "{")) // Ticket #5203: Invalid code, bailout
        return true;

    // Used later to check if the body belongs to a "if"
    const bool is_if = tok->str() == "if";

    for (; tok && 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;
}
//---------------------------------------------------------------------------

static bool checkMinSizes(const std::list<Library::ArgumentChecks::MinSize> &minsizes, const Token * const ftok, const std::size_t arraySize, const Token **charSizeToken)
{
    if (charSizeToken)
        *charSizeToken = nullptr;

    if (minsizes.empty())
        return false;

    // All conditions must be true
    bool error = true;
    for (std::list<Library::ArgumentChecks::MinSize>::const_iterator minsize = minsizes.begin(); minsize != minsizes.end(); ++minsize) {
        if (!error)
            return false;
        error = false;
        const Token *argtok = ftok->tokAt(2);
        for (int argnum = 1; argtok && argnum < minsize->arg; argnum++)
            argtok = argtok->nextArgument();
        if (!argtok)
            return false;
        switch (minsize->type) {
        case Library::ArgumentChecks::MinSize::ARGVALUE:
            if (Token::Match(argtok, "%num% ,|)")) {
                const MathLib::bigint sz = MathLib::toLongNumber(argtok->str());
                if ((std::size_t)sz > arraySize)
                    error = true;
            } else if (argtok->type() == Token::eChar && Token::Match(argtok->next(), ",|)") && charSizeToken)
                *charSizeToken = argtok; //sizeArgumentAsCharError(argtok);
            break;
        case Library::ArgumentChecks::MinSize::MUL:
            // TODO: handle arbitrary arg2
            if (minsize->arg2 == minsize->arg+1 && Token::Match(argtok, "%num% , %num% ,|)")) {
                const MathLib::bigint sz = MathLib::toLongNumber(argtok->str()) * MathLib::toLongNumber(argtok->strAt(2));
                if ((std::size_t)sz > arraySize)
                    error = true;
            }
            break;
        case Library::ArgumentChecks::MinSize::STRLEN: {
            const Token *strtoken = argtok->getValueTokenMaxStrLength();
            if (strtoken && Token::getStrLength(strtoken) >= arraySize)
                error = true;
        }
        break;
        case Library::ArgumentChecks::MinSize::SIZEOF:
            if (argtok->type() == Token::eString && Token::getStrLength(argtok) >= arraySize)
                error = true;
            break;
        case Library::ArgumentChecks::MinSize::NONE:
            return false;
        };
    }
    return error;
}

void CheckBufferOverrun::checkFunctionParameter(const Token &ftok, unsigned int par, const ArrayInfo &arrayInfo, const std::list<const Token *>& callstack)
{
    const std::list<Library::ArgumentChecks::MinSize> * const minsizes = _settings->library.argminsizes(ftok.str(),par);

    if (minsizes && (!(Token::simpleMatch(ftok.previous(), ".") || Token::Match(ftok.tokAt(-2), "!!std ::")))) {
        if (arrayInfo.element_size() == 0)
            return;

        MathLib::bigint arraySize = arrayInfo.element_size();
        for (std::size_t i = 0; i < arrayInfo.num().size(); ++i)
            arraySize *= arrayInfo.num(i);

        const Token *charSizeToken = nullptr;
        if (checkMinSizes(*minsizes, &ftok, (std::size_t)arraySize, &charSizeToken))
            bufferOverrunError(callstack, arrayInfo.varname());
        if (charSizeToken)
            sizeArgumentAsCharError(charSizeToken);
    }

    // Calling a user function?
    // only 1-dimensional arrays can be checked currently
    else if (arrayInfo.num().size() == 1) {
        const Function* const func = ftok.function();

        if (func && func->hasBody) {
            // Get corresponding parameter..
            const Variable* const 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->declarationId() == 0)
                return;

            // Check the parameter usage in the function scope..
            for (const Token* ftok2 = func->functionScope->classStart; ftok2 != func->functionScope->classEnd; ftok2 = ftok2->next()) {
                if (Token::Match(ftok2, "if|for|switch|while (")) {
                    // bailout if there is buffer usage..
                    if (bailoutIfSwitch(ftok2, parameter->declarationId())) {
                        break;
                    }

                    // no bailout is needed. skip the if-block
                    else {
                        // goto end of if block..
                        ftok2 = ftok2->linkAt(1)->linkAt(1);
                        if (Token::simpleMatch(ftok2, "} else {"))
                            ftok2 = ftok2->linkAt(2);
                        if (!ftok2)
                            break;
                        continue;
                    }
                }

                if (ftok2->str() == "}")
                    break;

                if (ftok2->varId() == parameter->declarationId()) {
                    if (Token::Match(ftok2->previous(), "-- %var%") ||
                        Token::Match(ftok2, "%var% --"))
                        break;

                    if (Token::Match(ftok2->previous(), ";|{|}|%op% %var% [ %num% ]")) {
                        const MathLib::bigint index = MathLib::toLongNumber(ftok2->strAt(2));
                        if (index >= 0 && arrayInfo.num(0) > 0 && index >= arrayInfo.num(0)) {
                            std::list<const Token *> callstack2(callstack);
                            callstack2.push_back(ftok2);

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

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

                // Calling function..
                if (Token::Match(ftok2, "%var% (")) {
                    ArrayInfo ai(arrayInfo);
                    ai.declarationId(parameter->declarationId());
                    checkFunctionCall(ftok2, ai, callstack);
                }
            }
        }
    }

    // Check 'float x[10]' arguments in declaration
    if (_settings->isEnabled("warning")) {
        const Function* const func = ftok.function();

        // If argument is '%type% a[num]' then check bounds against num
        if (func) {
            const Variable* const argument = func->getArgumentVar(par-1);
            const Token *nameToken;
            if (argument && Token::Match(argument->typeStartToken(), "%type% %var% [ %num% ] [,)[]")
                && (nameToken = argument->nameToken()) != nullptr) {
                const Token *tok2 = nameToken->next();

                MathLib::bigint argsize = _tokenizer->sizeOfType(argument->typeStartToken());
                if (argsize == 100) // unknown size
                    argsize = 0;
                while (Token::Match(tok2, "[ %num% ] [,)[]")) {
                    argsize *= MathLib::toLongNumber(tok2->strAt(1));
                    tok2 = tok2->tokAt(3);
                }

                MathLib::bigint arraysize = arrayInfo.element_size();
                if (arraysize == 100) // unknown size
                    arraysize = 0;
                for (std::size_t i = 0; i < arrayInfo.num().size(); i++)
                    arraysize *= arrayInfo.num(i);

                if (Token::Match(tok2, "[,)]") && arraysize > 0 && argsize > arraysize)
                    argumentSizeError(&ftok, ftok.str(), arrayInfo.varname());
            }
        }
    }
}


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 unsigned int declarationId = arrayInfo.declarationId();

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

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;

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

    const MathLib::bigint total_size = arrayInfo.element_size() * size;
    const unsigned int declarationId = arrayInfo.declarationId();

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

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

    // ValueFlow array index..
    if ((declarationId > 0 && Token::Match(tok, "%varid% [", declarationId)) ||
        (declarationId == 0 && Token::Match(tok, (varnames + " [").c_str()))) {

        const Token *tok2 = tok;
        while (tok2->str() != "[")
            tok2 = tok2->next();
        valueFlowCheckArrayIndex(tok2, arrayInfo);
    }

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

    const bool isPortabilityEnabled = _settings->isEnabled("portability");

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

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

        // Array index..
        if ((declarationId > 0 && ((tok->str() == "return" || (!tok->isName() && !Token::Match(tok, "[.&]"))) && Token::Match(tok->next(), "%varid% [ %num% ]", declarationId))) ||
            (declarationId == 0 && ((tok->str() == "return" || (!tok->isName() && !Token::Match(tok, "[.&]"))) && (Token::Match(tok->next(), (varnames + " [ %num% ]").c_str()) || Token::Match(tok->next(), (varname[0] +" [ %num% ] . " + varname[1] + " [ %num% ]").c_str()))))) {
            std::vector<MathLib::bigint> indexes;
            const Token *tok2 = tok->tokAt(2 + varcount);
            for (; Token::Match(tok2, "[ %num% ]"); tok2 = tok2->tokAt(3)) {
                const MathLib::bigint index = MathLib::toLongNumber(tok2->strAt(1));
                indexes.push_back(index);
            }
            for (; Token::Match(tok2->tokAt(3), "[ %num% ]"); tok2 = tok2->tokAt(3)) {
                const MathLib::bigint index = MathLib::toLongNumber(tok2->strAt(4));
                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 (std::size_t i = 0; i < indexes.size(); ++i) {
                    const 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);

                // taking address of 1 past end?
                if (totalIndex == totalElements) {
                    const bool addr = (tok3 && (tok3->str() == "&" ||
                                                Token::simpleMatch(tok3->previous(), "& (")));
                    if (addr)
                        continue;
                }

                // Is totalIndex in bounds?
                if (totalIndex > totalElements || totalIndex < 0) {
                    arrayIndexOutOfBoundsError(tok->tokAt(1 + varcount), arrayInfo, indexes);
                }
                // Is any array index out of bounds?
                else {
                    // check each index for overflow
                    for (std::size_t i = 0; i < indexes.size(); ++i) {
                        if (indexes[i] >= arrayInfo.num(i)) {
                            if (indexes.size() == 1U) {
                                arrayIndexOutOfBoundsError(tok->tokAt(1 + varcount), 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 + varcount), arrayInfo, indexes);
                                break; // only warn about the first one
                            }
                        }
                    }
                }
            }
            tok = tok2;
            continue;
        }

        // memset, memcmp, memcpy, strncpy, fgets..
        if (declarationId == 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);
        }

        // Writing data into array..
        if ((declarationId > 0 && Token::Match(tok, "strcpy|strcat ( %varid% , %str% )", declarationId)) ||
            (declarationId == 0 && Token::Match(tok, ("strcpy|strcat ( " + varnames + " , %str% )").c_str()))) {
            const std::size_t len = Token::getStrLength(tok->tokAt(varcount + 4));
            if (total_size > 0 && len >= (unsigned int)total_size) {
                bufferOverrunError(tok, declarationId > 0 ? emptyString : varnames);
                continue;
            }
        } else if ((declarationId > 0 && Token::Match(tok, "strcpy|strcat ( %varid% , %var% )", declarationId)) ||
                   (declarationId == 0 && Token::Match(tok, ("strcpy|strcat ( " + varnames + " , %var% )").c_str()))) {
            const Variable *var = tok->tokAt(4)->variable();
            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 = declarationId > 0 ? std::string("strcat ( %varid% , %str% ) ;") : ("strcat ( " + varnames + " , %str% ) ;");
        if (Token::Match(tok, strcatPattern.c_str(), declarationId)) {
            std::size_t charactersAppend = 0;
            const Token *tok2 = tok;

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

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

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

            const ArrayInfo arrayInfo1(declarationId, 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 (declarationId && Token::Match(tok, "= %varid% + %num% ;", declarationId)) {
            const MathLib::bigint index = MathLib::toLongNumber(tok->strAt(3));
            if (isPortabilityEnabled && index > size)
                pointerOutOfBoundsError(tok->next(), "buffer");
            if (index >= size && Token::Match(tok->tokAt(-2), "[;{}] %varid% =", declarationId))
                pointerIsOutOfBounds = true;
        }

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

void CheckBufferOverrun::valueFlowCheckArrayIndex(const Token * const tok, const ArrayInfo &arrayInfo)
{
    // Declaration in global scope?
    if (tok->scope()->type == Scope::eGlobal)
        return;
    /*
         {
            const Token *parent = tok->astParent();
            while (Token::Match(parent, "%var%|::|*|&"))
                parent = parent->astParent();
            if (parent && !Token::simpleMatch(parent, "="))
                return;
        }
    */
    // Taking address?
    bool addressOf = false;
    {
        const Token *tok2 = tok->astParent();
        while (Token::Match(tok2, "%var%|.|::|["))
            tok2 = tok2->astParent();
        addressOf = tok2 && tok2->str() == "&" && !(tok2->astOperand1() && tok2->astOperand2());
    }

    // Look for errors first
    for (int warn = 0; warn == 0 || warn == 1; ++warn) {
        // Negative index..
        for (const Token *tok2 = tok; tok2 && tok2->str() == "["; tok2 = tok2->link()->next()) {
            const Token *index = tok2->astOperand2();
            if (!index)
                continue;
            const ValueFlow::Value *value = index->getValueLE(-1LL,_settings);
            if (value)
                negativeIndexError(index, *value);
        }

        // Index out of bounds..
        std::vector<ValueFlow::Value> indexes;
        unsigned int valuevarid = 0;
        for (const Token *tok2 = tok; indexes.size() < arrayInfo.num().size() && Token::Match(tok2, "["); tok2 = tok2->link()->next()) {
            if (!tok2->astOperand2()) {
                indexes.clear();
                break;
            }
            const ValueFlow::Value *value = tok2->astOperand2()->getMaxValue(warn == 1);
            if (!value) {
                indexes.clear();
                break;
            }
            if (valuevarid == 0U)
                valuevarid = value->varId;
            if (value->varId > 0 && valuevarid != value->varId) {
                indexes.clear();
                break;
            }
            if (value->intvalue < 0) {
                indexes.clear();
                break;
            }
            indexes.push_back(*value);
        }
        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 (std::size_t i = 0; i < indexes.size(); ++i) {
                const std::size_t ri = indexes.size() - 1 - i;
                totalIndex += indexes[ri].intvalue * totalElements;
                totalElements *= arrayInfo.num(ri);
            }

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

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

            // Is totalIndex in bounds?
            if (totalIndex >= totalElements) {
                arrayIndexOutOfBoundsError(tok, arrayInfo, indexes);
                break;
            }

            // Is any array index out of bounds?
            else {
                // check each index for overflow
                for (std::size_t i = 0; i < indexes.size(); ++i) {
                    if (indexes[i].intvalue >= 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
                        }
                    }
                }
            }
        }
    }
}



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);

    const unsigned int declarationId = arrayInfo.declarationId();

    const bool isPortabilityEnabled = _settings->isEnabled("portability");
    const bool isWarningEnabled = _settings->isEnabled("warning");

    for (const Token* const end = tok->scope()->classEnd; tok != end; tok = tok->next()) {
        if (tok->varId() == declarationId) {
            if (tok->strAt(1) == "[") {
                valueFlowCheckArrayIndex(tok->next(), arrayInfo);
            }

            // undefined behaviour: result of pointer arithmetic is out of bounds
            else if (isPortabilityEnabled && Token::Match(tok->previous(), "= %varid% + %num% ;", declarationId)) {
                const MathLib::bigint index = MathLib::toLongNumber(tok->strAt(2));
                if (index < 0 || index > arrayInfo.num(0)) {
                    pointerOutOfBoundsError(tok, "array");
                }
            }
        }

        else if (!tok->scope()->isExecutable()) // No executable code outside of executable scope - continue to increase performance
            continue;

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

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

            if ((Token::Match(tok, "strncpy|strncat ( %varid% ,", declarationId) && 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 (isWarningEnabled && num >= total_size && _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% ,", declarationId) && 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 (total_size > 0 && Token::Match(tok, "strcpy|strcat ( %varid% , %str% )", declarationId)) {
                const std::size_t len = Token::getStrLength(tok->tokAt(4));
                if (len >= (unsigned int)total_size) {
                    bufferOverrunError(tok, arrayInfo.varname());
                    continue;
                }
            }

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

                while (tok2 && Token::Match(tok2, "strcat ( %varid% , %str% ) ;", declarationId)) {
                    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% [,)]", declarationId)) {
                checkSprintfCall(tok, total_size);
            }

            // snprintf..
            if (total_size > 0 && Token::Match(tok, "snprintf ( %varid% , %num% ,", declarationId)) {
                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 && Token::Match(tok, "readlink|readlinkat ("))
                checkReadlinkBufferUsage(tok, scope_begin, declarationId, total_size);

        }
    }
}

//---------------------------------------------------------------------------
// Checking member variables of structs..
//---------------------------------------------------------------------------
bool CheckBufferOverrun::isArrayOfStruct(const Token* tok, int &position)
{
    if (Token::Match(tok->next(), "%var% [ %num% ] ")) {
        tok = tok->tokAt(4);
        int i = 1;
        for (;;) {
            if (Token::Match(tok->next(), "[ %num% ] ")) {
                i++;
                tok = tok->tokAt(4);
            } else
                break;
        }
        if (Token::simpleMatch(tok->next(),";")) {
            position = i;
            return true;
        }
    }
    return false;
}

void CheckBufferOverrun::checkReadlinkBufferUsage(const Token* ftok, const Token *scope_begin, const unsigned int varid, const MathLib::bigint total_size)
{
    const std::string& funcname = ftok->str();

    const Token* bufParam = ftok->tokAt(2)->nextArgument();
    if (funcname == "readlinkat")
        bufParam = bufParam ? bufParam->nextArgument() : nullptr;
    if (!Token::Match(bufParam, "%varid% , %num% )", varid))
        return;

    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;

    // only writing a part of the buffer
    if (n < total_size)
        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(ftok, bufParam->str(), funcname);
    } else if (n == total_size) {
        possibleReadlinkBufferOverrunError(ftok, 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% ]")) {
            const std::size_t strLen = tok->str().size() - 2; // Don't count enclosing quotes
            const std::size_t index = (std::size_t)std::atoi(tok->strAt(2).c_str());
            if (index > strLen)
                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 * const var = symbolDatabase->getVariableFromVarId(i);
        if (var && var->isArray() && var->dimension(0) > 0) {
            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();
            const ArrayInfo arrayInfo(var, _tokenizer, i);
            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
            const Variable *var = nullptr;

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

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

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

                if (size < 0) {
                    negativeMemoryAllocationSizeError(tok->next()->next());
                }

                /** @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
                const unsigned int sizeOfType = _tokenizer->sizeOfType(var->typeStartToken());
                if (sizeOfType > 0) {
                    size /= static_cast<int>(sizeOfType);
                }
                if (size < 0) {
                    negativeMemoryAllocationSizeError(tok->next()->next());
                }
            } else {
                continue;
            }

            if (var == 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(var->declarationId(), 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) {
            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;

                        // find all array variables
                        int posOfSemicolon = -1;

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

                        else if (isArrayOfStruct(tok3,posOfSemicolon)) {
                            varname[0] = tok3->strAt(1);

                            int pos = 2;
                            for (int k = 0 ; k < posOfSemicolon; k++) {
                                for (int index = pos; index < (pos + 3); index++)
                                    tok3->strAt(index);
                                pos += 3;
                            }
                        }

                        // 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 || arrayInfo.element_size() == 0)
                                                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 = nullptr;
                        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.declarationId(0); // do variable lookup by variable and member names rather than varid
                        std::string varnames; // use class and member name for messages
                        for (std::size_t k = 0; k < varname.size(); ++k)
                            varnames += (k == 0 ? "" : ".") + varname[k];

                        temp.varname(varnames);
                        checkScope(checkTok, varname, temp);
                    }
                }
            }
        }
    }
}
//---------------------------------------------------------------------------

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

void CheckBufferOverrun::bufferOverrun2()
{
    // singlepass checking using ast, symboldatabase and valueflow
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
        // Array index
        if (!Token::Match(tok, "%var% ["))
            continue;

        // TODO: what to do about negative index..
        const Token *index = tok->next()->astOperand2();
        if (index && index->getValueLE(-1LL,_settings))
            continue;

        // Set full varname..
        std::string varname(tok->str());
        if (tok->astParent() && tok->astParent()->str() == ".") {
            const Token *parent = tok->astParent();
            while (parent->astParent() && parent->astParent()->str() == ".")
                parent = parent->astParent();
            varname = parent->expressionString();
        }


        const Token * const strtoken = tok->getValueTokenMinStrSize();
        if (strtoken) {
            ArrayInfo arrayInfo(tok->varId(), varname, 1U, Token::getStrSize(strtoken));
            valueFlowCheckArrayIndex(tok->next(), arrayInfo);
        }

        else {
            const Variable * const var = tok->variable();
            if (!var || var->nameToken() == tok || !var->isArray())
                continue;

            // TODO: last array in struct..
            if (var->dimension(0) <= 1 && Token::simpleMatch(var->nameToken()->linkAt(1),"] ; }"))
                continue;

            ArrayInfo arrayInfo(var,_tokenizer);
            arrayInfo.varname(varname);

            valueFlowCheckArrayIndex(tok->next(), arrayInfo);
        }
    }
}
//---------------------------------------------------------------------------

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 (i < input_string.length() - 1 && 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);
                const 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(nullptr);
        } else // Parameter is more complex than just a value or variable. Ignore it for now and skip to next token.
            parameters.push_back(nullptr);

        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;
        }
    }
}

//---------------------------------------------------------------------------
// memcpy(temp, "hello world", 50);
//---------------------------------------------------------------------------
void CheckBufferOverrun::checkStringArgument()
{
    const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
    std::size_t functions = symbolDatabase->functionScopes.size();
    for (std::size_t functionIndex = 0; functionIndex < functions; ++functionIndex) {
        const Scope * const scope = symbolDatabase->functionScopes[functionIndex];
        for (const Token *tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
            if (!Token::Match(tok, "%var% (") || !_settings->library.hasminsize(tok->str()))
                continue;

            unsigned int argnr = 1;
            for (const Token *argtok = tok->tokAt(2); argtok; argtok = argtok->nextArgument(), argnr++) {
                if (!Token::Match(argtok, "%var%|%str% ,|)"))
                    continue;
                const Token *strtoken = argtok->getValueTokenMinStrSize();
                if (!strtoken)
                    continue;
                const std::list<Library::ArgumentChecks::MinSize> *minsizes = _settings->library.argminsizes(tok->str(), argnr);
                if (!minsizes)
                    continue;
                if (checkMinSizes(*minsizes, tok, Token::getStrSize(strtoken), nullptr))
                    bufferOverrunError(argtok);
            }
        }
    }
}

//---------------------------------------------------------------------------
// 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 Function * function = symbolDatabase->functionScopes[i]->function;
        if (function) {
            const Token* tok = function->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::negativeIndexError(const Token *tok, const ValueFlow::Value &index)
{
    std::ostringstream ostr;
    ostr << "Array index " << index.intvalue << " is out of bounds.";
    if (index.condition)
        ostr << " Otherwise there is useless condition at line " << index.condition->linenr() << ".";
    reportError(tok, index.condition ? Severity::warning : Severity::error, "negativeIndex", ostr.str(), index.inconclusive);
}

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

CheckBufferOverrun::ArrayInfo::ArrayInfo(const Variable *var, const Tokenizer *tokenizer, const unsigned int forcedeclid)
    : _varname(var->name()), _declarationId((forcedeclid == 0U) ? var->declarationId() : forcedeclid)
{
    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());
}

/**
 * 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), _declarationId(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 (std::size_t i = 0; i < _num.size(); ++i)
        n *= _num[i];
    if (uvalue > n)
        n = uvalue;
    return ArrayInfo(_declarationId, _varname, _element_size, n - uvalue);
}



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

    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 * const scope = symbolDatabase->functionScopes[i];
        for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
            if (Token::Match(tok, "%var% [ %var% ]")) {
                tok = tok->tokAt(2);
                unsigned int indexID = tok->varId();
                if (!indexID)
                    continue;

                const std::string& indexName(tok->str());

                // skip array index..
                tok = tok->tokAt(2);
                while (tok && tok->str() == "[")
                    tok = tok->link()->next();

                // syntax error
                if (!tok)
                    return;

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

                // skip close parenthesis
                if (tok->str() == ")")
                    tok = tok->next();

                // check if array index is ok
                // statement can be closed in parentheses, so "(| " is using
                if (Token::Match(tok, "&& (| %varid% <|<=", indexID))
                    arrayIndexThenCheckError(tok, indexName);
                else if (Token::Match(tok, "&& (| %any% >|>= %varid% !!+", indexID))
                    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 checked 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.");
}

// -------------------------------------------------------------------------------------
// Check the second and the third parameter of the POSIX function write and validate
// their values.
// The parameters have the following meaning:
// - 1.parameter: file descripter (not required for this check)
// - 2.parameter: is a null terminated character string of the content to write.
// - 3.parameter: the number of bytes to write.
//
// This check is triggered if the size of the string ( 2. parameter) is lower than
// the number of bytes provided at the 3. parameter.
//
// References:
//  - http://pubs.opengroup.org/onlinepubs/9699919799/functions/write.html
//  - http://gd.tuwien.ac.at/languages/c/programming-bbrown/c_075.htm
//  - http://codewiki.wikidot.com/c:system-calls:write
// -------------------------------------------------------------------------------------
void CheckBufferOverrun::writeOutsideBufferSize()
{
    if (!_settings->standards.posix)
        return;

    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 * const scope = symbolDatabase->functionScopes[i];
        for (const Token *tok = scope->classStart; tok && tok != scope->classEnd; tok = tok->next()) {
            if (Token::Match(tok, "pwrite|write (") && Token::Match(tok->tokAt(2)->nextArgument(), "%str% , %num%")) {
                const std::string & functionName(tok->str());
                tok = tok->tokAt(2)->nextArgument(); // set tokenptr to %str% parameter
                const std::size_t stringLength = Token::getStrLength(tok)+1; // zero-terminated string!
                tok = tok->tokAt(2); // set tokenptr to %num% parameter
                const MathLib::bigint writeLength = MathLib::toLongNumber(tok->str());
                if (static_cast<std::size_t>(writeLength) > stringLength)
                    writeOutsideBufferSizeError(tok, stringLength, writeLength, functionName);
            }
        }
    }
}

void CheckBufferOverrun::writeOutsideBufferSizeError(const Token *tok, const std::size_t stringLength, const MathLib::bigint writeLength, const std::string &strFunctionName)
{
    reportError(tok, Severity::error, "writeOutsideBufferSize",
                "Writing " + MathLib::toString(writeLength-stringLength) + " bytes outside buffer size.\n"
                "The number of bytes to write (" + MathLib::toString(writeLength) + " bytes) are bigger than the source buffer (" +MathLib::toString(stringLength)+ " bytes)."
                " Please check the second and the third parameter of the function '"+strFunctionName+"'.");
}