2188 lines
89 KiB
C++
2188 lines
89 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2013 Daniel Marjamäki and Cppcheck team.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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//---------------------------------------------------------------------------
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// Buffer overrun..
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//---------------------------------------------------------------------------
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#include "checkbufferoverrun.h"
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#include "tokenize.h"
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#include "errorlogger.h"
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#include "mathlib.h"
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#include "symboldatabase.h"
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#include <algorithm>
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#include <sstream>
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#include <list>
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#include <cassert> // <- assert
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#include <cstdlib>
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//---------------------------------------------------------------------------
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// Register this check class (by creating a static instance of it)
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namespace {
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CheckBufferOverrun instance;
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}
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//---------------------------------------------------------------------------
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static void makeArrayIndexOutOfBoundsError(std::ostream& oss, const CheckBufferOverrun::ArrayInfo &arrayInfo, const std::vector<MathLib::bigint> &index)
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{
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oss << "Array '" << arrayInfo.varname();
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for (unsigned int i = 0; i < arrayInfo.num().size(); ++i)
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oss << "[" << arrayInfo.num(i) << "]";
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if (index.size() == 1)
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oss << "' accessed at index " << index[0] << ", which is";
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else {
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oss << "' index " << arrayInfo.varname();
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for (unsigned int i = 0; i < index.size(); ++i)
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oss << "[" << index[i] << "]";
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}
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oss << " out of bounds.";
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}
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void CheckBufferOverrun::arrayIndexOutOfBoundsError(const Token *tok, const ArrayInfo &arrayInfo, const std::vector<MathLib::bigint> &index)
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{
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std::ostringstream oss;
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makeArrayIndexOutOfBoundsError(oss, arrayInfo, index);
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reportError(tok, Severity::error, "arrayIndexOutOfBounds", oss.str());
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}
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void CheckBufferOverrun::arrayIndexOutOfBoundsError(const std::list<const Token *> &callstack, const ArrayInfo &arrayInfo, const std::vector<MathLib::bigint> &index)
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{
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std::ostringstream oss;
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makeArrayIndexOutOfBoundsError(oss, arrayInfo, index);
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reportError(callstack, Severity::error, "arrayIndexOutOfBounds", oss.str());
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}
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static std::string bufferOverrunMessage(std::string varnames)
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{
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varnames.erase(std::remove(varnames.begin(), varnames.end(), ' '), varnames.end());
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std::string errmsg("Buffer is accessed out of bounds");
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if (!varnames.empty())
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errmsg += ": " + varnames;
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else
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errmsg += ".";
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return errmsg;
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}
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void CheckBufferOverrun::bufferOverrunError(const Token *tok, const std::string &varnames)
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{
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reportError(tok, Severity::error, "bufferAccessOutOfBounds", bufferOverrunMessage(varnames));
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}
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void CheckBufferOverrun::bufferOverrunError(const std::list<const Token *> &callstack, const std::string &varnames)
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{
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reportError(callstack, Severity::error, "bufferAccessOutOfBounds", bufferOverrunMessage(varnames));
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}
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void CheckBufferOverrun::possibleBufferOverrunError(const Token *tok, const std::string &src, const std::string &dst, bool cat)
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{
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if (cat)
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reportError(tok, Severity::warning, "possibleBufferAccessOutOfBounds",
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"Possible buffer overflow if strlen(" + src + ") is larger than sizeof(" + dst + ")-strlen(" + dst +").\n"
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"Possible buffer overflow if strlen(" + src + ") is larger than sizeof(" + dst + ")-strlen(" + dst +"). "
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"The source buffer is larger than the destination buffer so there is the potential for overflowing the destination buffer.");
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else
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reportError(tok, Severity::warning, "possibleBufferAccessOutOfBounds",
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"Possible buffer overflow if strlen(" + src + ") is larger than or equal to sizeof(" + dst + ").\n"
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"Possible buffer overflow if strlen(" + src + ") is larger than or equal to sizeof(" + dst + "). "
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"The source buffer is larger than the destination buffer so there is the potential for overflowing the destination buffer.");
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}
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void CheckBufferOverrun::possibleReadlinkBufferOverrunError(const Token* tok, const std::string &funcname, const std::string &varname)
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{
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const std::string errmsg = funcname + "() might return the full size of '" + varname + "'. Lower the supplied size by one.\n" +
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funcname + "() might return the full size of '" + varname + "'. "
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"If a " + varname + "[len] = '\\0'; statement follows, it will overrun the buffer. Lower the supplied size by one.";
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reportError(tok, Severity::warning, "possibleReadlinkBufferOverrun", errmsg, true);
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}
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void CheckBufferOverrun::strncatUsageError(const Token *tok)
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{
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if (_settings && !_settings->isEnabled("style"))
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return;
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reportError(tok, Severity::warning, "strncatUsage",
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"Dangerous usage of strncat - 3rd parameter is the maximum number of characters to append.\n"
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"strncat appends at max its 3rd parameter's amount of characters. The safe way to use "
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"strncat is to calculate remaining space in the buffer and use it as 3rd parameter.");
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}
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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)
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{
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std::ostringstream oss;
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oss << what << " is out of bounds";
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if (show_size_info)
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oss << ": Supplied size " << supplied_size << " is larger than actual size " << actual_size;
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oss << '.';
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reportError(tok, Severity::error, "outOfBounds", oss.str());
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}
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void CheckBufferOverrun::pointerOutOfBoundsError(const Token *tok, const std::string &object)
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{
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reportError(tok, Severity::portability, "pointerOutOfBounds", "Undefined behaviour: Pointer arithmetic result does not point into or just past the end of the " + object + ".\n"
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"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");
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}
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void CheckBufferOverrun::sizeArgumentAsCharError(const Token *tok)
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{
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if (_settings && !_settings->isEnabled("style"))
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return;
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reportError(tok, Severity::warning, "sizeArgumentAsChar", "The size argument is given as a char constant.");
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}
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void CheckBufferOverrun::terminateStrncpyError(const Token *tok, const std::string &varname)
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{
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reportError(tok, Severity::warning, "terminateStrncpy",
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"The buffer '" + varname + "' may not be null-terminated after the call to strncpy().\n"
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"If the source string's size fits or exceeds the given size, strncpy() does not add a "
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"zero at the end of the buffer. This causes bugs later in the code if the code "
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"assumes buffer is null-terminated.", true);
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}
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void CheckBufferOverrun::cmdLineArgsError(const Token *tok)
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{
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reportError(tok, Severity::error, "insecureCmdLineArgs", "Buffer overrun possible for long command line arguments.");
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}
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void CheckBufferOverrun::bufferNotZeroTerminatedError(const Token *tok, const std::string &varname, const std::string &function)
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{
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const std::string errmsg = "The buffer '" + varname + "' is not null-terminated after the call to " + function + "().\n"
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"The buffer '" + varname + "' is not null-terminated after the call to " + function + "(). "
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"This will cause bugs later in the code if the code assumes the buffer is null-terminated.";
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reportError(tok, Severity::warning, "bufferNotZeroTerminated", errmsg, true);
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}
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void CheckBufferOverrun::argumentSizeError(const Token *tok, const std::string &functionName, const std::string &varname)
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{
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reportError(tok, Severity::style, "argumentSize", "the array " + varname + " is too small, the function " + functionName + " expects a bigger array");
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}
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//---------------------------------------------------------------------------
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//---------------------------------------------------------------------------
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// Check array usage..
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//---------------------------------------------------------------------------
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/**
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* @brief This is a helper class to be used with std::find_if
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*/
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class TokenStrEquals {
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public:
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/**
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* @param str Token::str() is compared against this.
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*/
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explicit TokenStrEquals(const std::string &str)
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: value(str) {
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}
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/**
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* Called automatically by std::find_if
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* @param tok Token inside the list
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*/
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bool operator()(const Token *tok) const {
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return value == tok->str();
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}
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private:
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TokenStrEquals& operator=(const TokenStrEquals&); // disallow assignments
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const std::string value;
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};
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/**
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* bailout if variable is used inside if/else/switch block or if there is "break"
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* @param tok token for "if" or "switch"
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* @param varid variable id
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* @return is bailout recommended?
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*/
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static bool bailoutIfSwitch(const Token *tok, const unsigned int varid)
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{
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// Used later to check if the body belongs to a "if"
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bool is_if = tok->str() == "if";
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const Token* end = tok->linkAt(1)->linkAt(1);
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if (Token::simpleMatch(end, "} else {")) // scan the else-block
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end = end->linkAt(2);
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for (; tok != end; tok = tok->next()) {
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// If scanning a "if" block then bailout for "break"
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if (is_if && (tok->str() == "break" || tok->str() == "continue"))
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return true;
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// bailout for "return"
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else if (tok->str() == "return")
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return true;
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// bailout if varid is found
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else if (tok->varId() == varid)
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return true;
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}
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// No bailout stuff found => return false
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return false;
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}
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/**
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* Parse for loop initialization statement. Look for a counter variable
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* \param tok [in] first token inside the parentheses
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* \param varid [out] varid of counter variable
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* \param varname [out] name of counter variable
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* \param init_value [out] init value of counter variable
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* \return success => pointer to the for loop condition. fail => 0. If 0 is returned and varname has been set then there is
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* a missing varid for the counter variable
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*/
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static const Token *for_init(const Token *tok, unsigned int &varid, std::string &varname, std::string &init_value)
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{
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if (Token::Match(tok, "%var% = %any% ;")) {
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if (tok->tokAt(2)->isNumber()) {
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init_value = tok->strAt(2);
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}
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varid = tok->varId();
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varname = tok->str();
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tok = tok->tokAt(4);
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if (varid == 0)
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return 0; // failed
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} else if (Token::Match(tok, "%type% %var% = %any% ;")) {
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if (tok->tokAt(3)->isNumber()) {
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init_value = tok->strAt(3);
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}
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varid = tok->next()->varId();
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varname = tok->next()->str();
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tok = tok->tokAt(5);
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} else if (Token::Match(tok, "%type% %type% %var% = %any% ;")) {
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if (tok->tokAt(4)->isNumber()) {
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init_value = tok->strAt(4);
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}
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varid = tok->tokAt(2)->varId();
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varname = tok->strAt(2);
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tok = tok->tokAt(6);
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} else
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return 0;
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if (!init_value.empty() && (Token::Match(tok, "-- %varid%", varid) || Token::Match(tok, "%varid% --", varid))) {
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init_value = MathLib::subtract(init_value, "1");
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}
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return tok;
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}
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/** Parse for condition */
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static bool for_condition(const Token *tok2, unsigned int varid, std::string &min_value, std::string &max_value, bool &maxMinFlipped)
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{
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if (Token::Match(tok2, "%varid% < %num% ;|&&|%oror%", varid) ||
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Token::Match(tok2, "%varid% != %num% ; ++ %varid%", varid) ||
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Token::Match(tok2, "%varid% != %num% ; %varid% ++", varid)) {
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maxMinFlipped = false;
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const MathLib::bigint value = MathLib::toLongNumber(tok2->strAt(2));
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max_value = MathLib::longToString(value - 1);
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} else if (Token::Match(tok2, "%varid% <= %num% ;|&&|%oror%", varid)) {
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maxMinFlipped = false;
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max_value = tok2->strAt(2);
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} else if (Token::Match(tok2, "%num% < %varid% ;|&&|%oror%", varid) ||
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Token::Match(tok2, "%num% != %varid% ; ++ %varid%", varid) ||
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Token::Match(tok2, "%num% != %varid% ; %varid% ++", varid)) {
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maxMinFlipped = true;
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const MathLib::bigint value = MathLib::toLongNumber(tok2->str());
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max_value = min_value;
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min_value = MathLib::longToString(value + 1);
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} else if (Token::Match(tok2, "%num% <= %varid% ;|&&|%oror%", varid)) {
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maxMinFlipped = true;
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max_value = min_value;
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min_value = tok2->str();
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} else {
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// parse condition
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while (tok2 && tok2->str() != ";") {
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if (tok2->str() == "(")
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tok2 = tok2->link();
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else if (tok2->str() == ")") // unexpected ")" => break
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break;
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if (tok2->str() == "&&" || tok2->str() == "||") {
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if (for_condition(tok2->next(), varid, min_value, max_value, maxMinFlipped))
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return true;
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}
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tok2 = tok2->next();
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}
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return false;
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}
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return true;
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}
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/**
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* calculate maximum value of loop variable
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* @param stepvalue token that contains the step value
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* @param min_value the minimum value of loop variable
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* @param max_value maximum value of the loop variable
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*/
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static bool for_maxvalue(const Token * const stepvalue, const std::string &min_value, std::string &max_value)
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{
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if (!MathLib::isInt(stepvalue->str()))
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return false;
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// We have for example code: "for(i=2;i<22;i+=6)
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// We can calculate that max value for i is 20, not 21
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// 21-2 = 19
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// 19/6 = 3
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// 6*3+2 = 20
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const MathLib::bigint num = MathLib::toLongNumber(stepvalue->str());
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MathLib::bigint max = MathLib::toLongNumber(max_value);
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const MathLib::bigint min = MathLib::toLongNumber(min_value);
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max = ((max - min) / num) * num + min;
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max_value = MathLib::longToString(max);
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return true;
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}
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/**
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* Parse the third sub-statement in for head
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* \param tok first token
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* \param varid variable id of counter
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* \param min_value min value of counter
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* \param max_value max value of counter
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* \param maxMinFlipped counting from max to min
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*/
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static bool for3(const Token * const tok,
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unsigned int varid,
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std::string &min_value,
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std::string &max_value,
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const bool maxMinFlipped)
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{
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assert(tok != 0);
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if (Token::Match(tok, "%varid% = %num% + %varid% )", varid)) {
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if (!for_maxvalue(tok->tokAt(2), min_value, max_value))
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return false;
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} else if (Token::Match(tok, "%varid% = %varid% + %num% )", varid)) {
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if (!for_maxvalue(tok->tokAt(4), min_value, max_value))
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return false;
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} else if (Token::Match(tok, "%varid% = %num% - %varid% )", varid)) {
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if (!for_maxvalue(tok->tokAt(2), min_value, max_value))
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return false;
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} else if (Token::Match(tok, "%varid% = %varid% - %num% )", varid)) {
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if (!for_maxvalue(tok->tokAt(4), min_value, max_value))
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return false;
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} else if (Token::Match(tok, "--| %varid% --| )", varid)) {
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if (!maxMinFlipped && MathLib::toLongNumber(min_value) < MathLib::toLongNumber(max_value)) {
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// Code relies on the fact that integer will overflow:
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// for (unsigned int i = 3; i < 5; --i)
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// Set min value in this case to zero.
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max_value = min_value;
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min_value = "0";
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}
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} else if (! Token::Match(tok, "++| %varid% ++| )", varid)) {
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return false;
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}
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return true;
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}
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/**
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* Check is the counter variable increased elsewhere inside the loop or used
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* for anything else except reading
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* \param tok1 first token of for-body
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* \param varid counter variable id
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* \return bailout needed => true
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*/
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static bool for_bailout(const Token * const tok1, unsigned int varid)
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{
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for (const Token *loopTok = tok1; loopTok && loopTok != tok1->link(); loopTok = loopTok->next()) {
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if (loopTok->varId() == varid) {
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// Counter variable used inside loop
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if (Token::Match(loopTok->next(), "++|--|=") ||
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(loopTok->previous()->type() == Token::eIncDecOp)) {
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return true;
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}
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}
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}
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return false;
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}
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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)
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{
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const std::string pattern = (arrayInfo.varid() ? std::string("%varid%") : arrayInfo.varname()) + " [ " + strindex + " ]";
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for (const Token* tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
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// TestBufferOverrun::array_index_for_question
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if (tok2->str() == "?") {
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// does condition check counter variable?
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bool usesCounter = false;
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const Token *tok3 = tok2->previous();
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while (Token::Match(tok3, "%comp%|%num%|%var%|)")) {
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if (tok3->str() == strindex) {
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usesCounter = true;
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break;
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}
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tok3 = tok3->previous();
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}
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// If strindex is used in the condition then skip the
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// conditional expressions
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if (usesCounter) {
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while (tok2 && !Token::Match(tok2, "[)],;]")) {
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if (tok2->str() == "(" || tok2->str() == "[")
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tok2 = tok2->link();
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tok2 = tok2->next();
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}
|
|
if (!tok2)
|
|
break;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
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 1001 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 = tok.function();
|
|
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Check 'float x[10]' arguments in declaration
|
|
if (_settings->isEnabled("style")) {
|
|
const Function* func = tok.function();
|
|
|
|
// If argument is '%type% a[num]' then check bounds against num
|
|
if (func) {
|
|
const Variable* argument = func->getArgumentVar(par-1);
|
|
const Token *nameToken;
|
|
if (argument && Token::Match(argument->typeStartToken(), "%type% %var% [ %num% ] [,)[]")
|
|
&& (nameToken = argument->nameToken()) != NULL) {
|
|
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 (unsigned int i = 0; i < arrayInfo.num().size(); i++)
|
|
arraysize *= arrayInfo.num(i);
|
|
|
|
if (Token::Match(tok2, "[,)]") && arraysize > 0 && argsize > arraysize)
|
|
argumentSizeError(&tok, tok.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 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 parentheses 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*> ¶meters)
|
|
{
|
|
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.");
|
|
}
|