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2245 lines (2108 loc) · 119 KB
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2026 Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
#include "checkio.h"
#include "astutils.h"
#include "errortypes.h"
#include "library.h"
#include "mathlib.h"
#include "platform.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenize.h"
#include "utils.h"
#include "vfvalue.h"
#include <algorithm>
#include <cctype>
#include <cstdlib>
#include <functional>
#include <list>
#include <map>
#include <set>
#include <sstream>
#include <unordered_set>
#include <utility>
#include <vector>
//---------------------------------------------------------------------------
// CVE ID used:
static const CWE CWE119(119U); // Improper Restriction of Operations within the Bounds of a Memory Buffer
static const CWE CWE398(398U); // Indicator of Poor Code Quality
static const CWE CWE474(474U); // Use of Function with Inconsistent Implementations
static const CWE CWE664(664U); // Improper Control of a Resource Through its Lifetime
static const CWE CWE685(685U); // Function Call With Incorrect Number of Arguments
static const CWE CWE686(686U); // Function Call With Incorrect Argument Type
static const CWE CWE687(687U); // Function Call With Incorrectly Specified Argument Value
static const CWE CWE704(704U); // Incorrect Type Conversion or Cast
static const CWE CWE910(910U); // Use of Expired File Descriptor
//---------------------------------------------------------------------------
// std::cout << std::cout;
//---------------------------------------------------------------------------
void CheckIOImpl::checkCoutCerrMisusage()
{
if (mTokenizer->isC())
return;
logChecker("CheckIO::checkCoutCerrMisusage"); // c
const SymbolDatabase * const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token *tok = scope->bodyStart; tok && tok != scope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "std :: cout|cerr !!.") && tok->next()->astParent() && tok->next()->astParent()->astOperand1() == tok->next()) {
const Token* tok2 = tok->next();
while (tok2->astParent() && tok2->astParent()->str() == "<<") {
tok2 = tok2->astParent();
if (tok2->astOperand2() && Token::Match(tok2->astOperand2()->previous(), "std :: cout|cerr"))
coutCerrMisusageError(tok, tok2->astOperand2()->strAt(1));
}
}
}
}
}
void CheckIOImpl::coutCerrMisusageError(const Token* tok, const std::string& streamName)
{
reportError(tok, Severity::error, "coutCerrMisusage", "Invalid usage of output stream: '<< std::" + streamName + "'.", CWE398, Certainty::normal);
}
//---------------------------------------------------------------------------
// fflush(stdin) <- fflush only applies to output streams in ANSI C
// fread(); fwrite(); <- consecutive read/write statements require repositioning in between
// fopen("","r"); fwrite(); <- write to read-only file (or vice versa)
// fclose(); fread(); <- Use closed file
//---------------------------------------------------------------------------
enum class OpenMode : std::uint8_t { CLOSED, READ_MODE, WRITE_MODE, RW_MODE, UNKNOWN_OM };
static OpenMode getMode(const std::string& str)
{
if (str.find('+', 1) != std::string::npos)
return OpenMode::RW_MODE;
if (str.find('w') != std::string::npos || str.find('a') != std::string::npos)
return OpenMode::WRITE_MODE;
if (str.find('r') != std::string::npos)
return OpenMode::READ_MODE;
return OpenMode::UNKNOWN_OM;
}
namespace {
struct Filepointer {
OpenMode mode;
nonneg int mode_indent{};
enum class Operation : std::uint8_t {NONE, UNIMPORTANT, READ, WRITE, POSITIONING, OPEN, CLOSE, UNKNOWN_OP} lastOperation = Operation::NONE;
nonneg int op_indent{};
enum class AppendMode : std::uint8_t { UNKNOWN_AM, APPEND, APPEND_EX };
AppendMode append_mode = AppendMode::UNKNOWN_AM;
enum class ReadMode : std::uint8_t { READ_TEXT, READ_BIN };
ReadMode read_mode = ReadMode::READ_BIN;
std::string filename;
explicit Filepointer(OpenMode mode_ = OpenMode::UNKNOWN_OM)
: mode(mode_) {}
};
const std::unordered_set<std::string> whitelist = { "clearerr", "feof", "ferror", "fgetpos", "ftell", "setbuf", "setvbuf", "ungetc", "ungetwc" };
}
void CheckIOImpl::checkFileUsage()
{
const bool windows = mSettings.platform.isWindows();
const bool printPortability = mSettings.severity.isEnabled(Severity::portability);
const bool printWarnings = mSettings.severity.isEnabled(Severity::warning);
std::map<int, Filepointer> filepointers;
logChecker("CheckIO::checkFileUsage");
const SymbolDatabase* symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Variable* var : symbolDatabase->variableList()) {
if (!var || !var->declarationId() || var->isArray() || !Token::simpleMatch(var->typeStartToken(), "FILE *"))
continue;
if (var->isLocal()) {
if (var->nameToken()->strAt(1) == "(") // initialize by calling "ctor"
filepointers.emplace(var->declarationId(), Filepointer(OpenMode::UNKNOWN_OM));
else
filepointers.emplace(var->declarationId(), Filepointer(OpenMode::CLOSED));
} else {
filepointers.emplace(var->declarationId(), Filepointer(OpenMode::UNKNOWN_OM));
// TODO: If all fopen calls we find open the file in the same type, we can set Filepointer::mode
}
}
for (const Scope * scope : symbolDatabase->functionScopes) {
int indent = 0;
for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "%name% (") && isUnevaluated(tok)) {
tok = tok->linkAt(1);
continue;
}
if (tok->function() && tok->function()->nestedIn)
continue;
if (tok->str() == "{")
indent++;
else if (tok->str() == "}") {
indent--;
for (std::pair<const int, Filepointer>& filepointer : filepointers) {
if (indent < filepointer.second.mode_indent) {
filepointer.second.mode_indent = 0;
filepointer.second.mode = OpenMode::UNKNOWN_OM;
}
if (indent < filepointer.second.op_indent) {
filepointer.second.op_indent = 0;
filepointer.second.lastOperation = Filepointer::Operation::UNKNOWN_OP;
}
}
} else if (tok->str() == "return" || tok->str() == "continue" || tok->str() == "break" || mSettings.library.isnoreturn(tok)) { // Reset upon return, continue or break
for (std::pair<const int, Filepointer>& filepointer : filepointers) {
filepointer.second.mode_indent = 0;
filepointer.second.mode = OpenMode::UNKNOWN_OM;
filepointer.second.op_indent = 0;
filepointer.second.lastOperation = Filepointer::Operation::UNKNOWN_OP;
}
} else if (Token::Match(tok, "%var% =") &&
(tok->strAt(2) != "fopen" && tok->strAt(2) != "freopen" && tok->strAt(2) != "tmpfile" &&
(windows ? (tok->str() != "_wfopen" && tok->str() != "_wfreopen") : true))) {
const auto i = filepointers.find(tok->varId());
if (i != filepointers.end()) {
i->second.mode = OpenMode::UNKNOWN_OM;
i->second.lastOperation = Filepointer::Operation::UNKNOWN_OP;
}
} else if (Token::Match(tok, "%name% (") && tok->previous() && (!tok->previous()->isName() || Token::Match(tok->previous(), "return|throw"))) {
std::string mode;
bool isftell = false;
const Token* fileTok = nullptr;
const Token* fileNameTok = nullptr;
Filepointer::Operation operation = Filepointer::Operation::NONE;
if ((tok->str() == "fopen" || tok->str() == "freopen" || tok->str() == "tmpfile" ||
(windows && (tok->str() == "_wfopen" || tok->str() == "_wfreopen"))) &&
tok->strAt(-1) == "=") {
if (tok->str() != "tmpfile") {
const Token* modeTok = tok->tokAt(2)->nextArgument();
if (modeTok && modeTok->tokType() == Token::eString)
mode = modeTok->strValue();
} else
mode = "wb+";
fileTok = tok->tokAt(-2);
operation = Filepointer::Operation::OPEN;
if (Token::Match(tok, "fopen ( %str% ,"))
fileNameTok = tok->tokAt(2);
} else if (windows && Token::Match(tok, "fopen_s|freopen_s|_wfopen_s|_wfreopen_s ( & %name%")) {
const Token* modeTok = tok->tokAt(2)->nextArgument()->nextArgument();
if (modeTok && modeTok->tokType() == Token::eString)
mode = modeTok->strValue();
fileTok = tok->tokAt(3);
operation = Filepointer::Operation::OPEN;
} else if ((tok->str() == "rewind" || tok->str() == "fseek" || tok->str() == "fsetpos" || tok->str() == "fflush") ||
(windows && tok->str() == "_fseeki64")) {
fileTok = tok->tokAt(2);
if (printPortability && fileTok && tok->str() == "fflush") {
if (fileTok->str() == "stdin")
fflushOnInputStreamError(tok, fileTok->str());
else {
const Filepointer& f = filepointers[fileTok->varId()];
if (f.mode == OpenMode::READ_MODE)
fflushOnInputStreamError(tok, fileTok->str());
}
}
operation = Filepointer::Operation::POSITIONING;
} else if (tok->str() == "fgetc" || tok->str() == "fgetwc" ||
tok->str() == "fgets" || tok->str() == "fgetws" || tok->str() == "fread" ||
tok->str() == "fscanf" || tok->str() == "fwscanf" || tok->str() == "getc" ||
(windows && (tok->str() == "fscanf_s" || tok->str() == "fwscanf_s"))) {
if (tok->str().find("scanf") != std::string::npos)
fileTok = tok->tokAt(2);
else
fileTok = tok->linkAt(1)->previous();
operation = Filepointer::Operation::READ;
} else if (tok->str() == "fputc" || tok->str() == "fputwc" ||
tok->str() == "fputs" || tok->str() == "fputws" || tok->str() == "fwrite" ||
tok->str() == "fprintf" || tok->str() == "fwprintf" || tok->str() == "putcc" ||
(windows && (tok->str() == "fprintf_s" || tok->str() == "fwprintf_s"))) {
if (tok->str().find("printf") != std::string::npos)
fileTok = tok->tokAt(2);
else
fileTok = tok->linkAt(1)->previous();
operation = Filepointer::Operation::WRITE;
} else if (tok->str() == "fclose") {
fileTok = tok->tokAt(2);
operation = Filepointer::Operation::CLOSE;
// #1473 Check if fclose is in a while loop condition
if (fileTok && fileTok->isVariable()) {
const Token* loopTok = tok->astTop()->previous();
if (loopTok && loopTok->str() == "while") {
const Token* bodyEnd = nullptr;
const Token* bodyStart = nullptr;
if (Token::simpleMatch(loopTok->previous(), "}") && loopTok->previous()->scope()->type == ScopeType::eDo) { // Handle do-while loops
bodyEnd = loopTok->previous();
bodyStart = bodyEnd->link();
} else {
bodyStart = loopTok->linkAt(1)->next();
bodyEnd = bodyStart->link();
}
// Do not trigger a warning if the loop always exits or if the file is opened again in the loop.
if (!isReturnScope(bodyEnd, mSettings.library) && Token::findmatch(bodyStart, "%var% =", bodyEnd, fileTok->varId()) == nullptr)
fcloseInLoopConditionError(tok, fileTok->str());
}
}
} else if (whitelist.find(tok->str()) != whitelist.end()) {
fileTok = tok->tokAt(2);
if ((tok->str() == "ungetc" || tok->str() == "ungetwc") && fileTok)
fileTok = fileTok->nextArgument();
else if (tok->str() == "ftell") {
isftell = true;
}
operation = Filepointer::Operation::UNIMPORTANT;
} else if (!Token::Match(tok, "if|for|while|catch|switch") && !mSettings.library.isFunctionConst(tok->str(), true)) {
const Token* const end2 = tok->linkAt(1);
if (scope->functionOf && scope->functionOf->isClassOrStruct() && !scope->function->isStatic() && ((tok->strAt(-1) != "::" && tok->strAt(-1) != ".") || tok->strAt(-2) == "this")) {
if (!tok->function() || (tok->function()->nestedIn && tok->function()->nestedIn->isClassOrStruct())) {
for (std::pair<const int, Filepointer>& filepointer : filepointers) {
const Variable* var = symbolDatabase->getVariableFromVarId(filepointer.first);
if (!var || !(var->isLocal() || var->isGlobal() || var->isStatic())) {
filepointer.second.mode = OpenMode::UNKNOWN_OM;
filepointer.second.mode_indent = 0;
filepointer.second.op_indent = indent;
filepointer.second.lastOperation = Filepointer::Operation::UNKNOWN_OP;
}
}
continue;
}
}
for (const Token* tok2 = tok->tokAt(2); tok2 != end2; tok2 = tok2->next()) {
if (tok2->varId() && filepointers.find(tok2->varId()) != filepointers.end()) {
fileTok = tok2;
operation = Filepointer::Operation::UNKNOWN_OP; // Assume that repositioning was last operation and that the file is opened now
break;
}
}
}
while (Token::Match(fileTok, "%name% ."))
fileTok = fileTok->tokAt(2);
if (!fileTok || !fileTok->varId() || fileTok->strAt(1) == "[")
continue;
// function call indicates: Its a File
filepointers.emplace(fileTok->varId(), Filepointer(OpenMode::UNKNOWN_OM));
Filepointer& f = filepointers[fileTok->varId()];
switch (operation) {
case Filepointer::Operation::OPEN:
if (fileNameTok) {
for (auto it = filepointers.cbegin(); it != filepointers.cend(); ++it) {
const Filepointer &fptr = it->second;
if (fptr.filename == fileNameTok->str() && (fptr.mode == OpenMode::RW_MODE || fptr.mode == OpenMode::WRITE_MODE))
incompatibleFileOpenError(tok, fileNameTok->str());
}
f.filename = fileNameTok->str();
}
f.mode = getMode(mode);
if (mode.find('a') != std::string::npos) {
if (f.mode == OpenMode::RW_MODE)
f.append_mode = Filepointer::AppendMode::APPEND_EX;
else
f.append_mode = Filepointer::AppendMode::APPEND;
}
else if (mode.find('r') != std::string::npos &&
mode.find('t') != std::string::npos) {
f.read_mode = Filepointer::ReadMode::READ_TEXT;
} else
f.append_mode = Filepointer::AppendMode::UNKNOWN_AM;
f.mode_indent = indent;
break;
case Filepointer::Operation::POSITIONING:
if (f.mode == OpenMode::CLOSED)
useClosedFileError(tok);
else if (f.append_mode == Filepointer::AppendMode::APPEND && tok->str() != "fflush" && printWarnings)
seekOnAppendedFileError(tok);
break;
case Filepointer::Operation::READ:
if (f.mode == OpenMode::CLOSED)
useClosedFileError(tok);
else if (f.mode == OpenMode::WRITE_MODE)
readWriteOnlyFileError(tok);
else if (f.lastOperation == Filepointer::Operation::WRITE)
ioWithoutPositioningError(tok);
break;
case Filepointer::Operation::WRITE:
if (f.mode == OpenMode::CLOSED)
useClosedFileError(tok);
else if (f.mode == OpenMode::READ_MODE)
writeReadOnlyFileError(tok);
else if (f.lastOperation == Filepointer::Operation::READ)
ioWithoutPositioningError(tok);
break;
case Filepointer::Operation::CLOSE:
if (f.mode == OpenMode::CLOSED)
useClosedFileError(tok);
else
f.mode = OpenMode::CLOSED;
f.mode_indent = indent;
break;
case Filepointer::Operation::UNIMPORTANT:
if (f.mode == OpenMode::CLOSED)
useClosedFileError(tok);
if (isftell && f.read_mode == Filepointer::ReadMode::READ_TEXT && printPortability)
ftellFileError(tok);
break;
case Filepointer::Operation::UNKNOWN_OP:
f.mode = OpenMode::UNKNOWN_OM;
f.mode_indent = 0;
break;
default:
break;
}
if (operation != Filepointer::Operation::NONE && operation != Filepointer::Operation::UNIMPORTANT) {
f.op_indent = indent;
f.lastOperation = operation;
}
}
}
for (std::pair<const int, Filepointer>& filepointer : filepointers) {
filepointer.second.op_indent = 0;
filepointer.second.mode = OpenMode::UNKNOWN_OM;
filepointer.second.lastOperation = Filepointer::Operation::UNKNOWN_OP;
}
}
}
void CheckIOImpl::fflushOnInputStreamError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::portability,
"fflushOnInputStream", "fflush() called on input stream '" + varname + "' may result in undefined behaviour on non-linux systems.", CWE398, Certainty::normal);
}
void CheckIOImpl::ioWithoutPositioningError(const Token *tok)
{
reportError(tok, Severity::error,
"IOWithoutPositioning", "Read and write operations without a call to a positioning function (fseek, fsetpos or rewind) or fflush in between result in undefined behaviour.", CWE664, Certainty::normal);
}
void CheckIOImpl::readWriteOnlyFileError(const Token *tok)
{
reportError(tok, Severity::error,
"readWriteOnlyFile", "Read operation on a file that was opened only for writing.", CWE664, Certainty::normal);
}
void CheckIOImpl::writeReadOnlyFileError(const Token *tok)
{
reportError(tok, Severity::error,
"writeReadOnlyFile", "Write operation on a file that was opened only for reading.", CWE664, Certainty::normal);
}
void CheckIOImpl::useClosedFileError(const Token *tok)
{
reportError(tok, Severity::error,
"useClosedFile", "Used file that is not opened.", CWE910, Certainty::normal);
}
void CheckIOImpl::fcloseInLoopConditionError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::warning,
"fcloseInLoopCondition",
"fclose() used as loop condition may skip loop body or double-close file handle.\n"
"fclose() closes '" + varname + "' each time it is evaluated. On success the loop body might never execute, on failure fclose() might be called again on the already-closed file handle.",
CWE910, Certainty::normal);
}
void CheckIOImpl::seekOnAppendedFileError(const Token *tok)
{
reportError(tok, Severity::warning,
"seekOnAppendedFile", "Repositioning operation performed on a file opened in append mode has no effect.", CWE398, Certainty::normal);
}
void CheckIOImpl::ftellFileError(const Token *tok)
{
reportError(tok, Severity::portability,
"ftellTextModeFile", "ftell() result is unspecified when file is opened in mode \"t\"", CWE474, Certainty::normal);
}
void CheckIOImpl::incompatibleFileOpenError(const Token *tok, const std::string &filename)
{
reportError(tok, Severity::warning,
"incompatibleFileOpen", "The file '" + filename + "' is opened for read and write access at the same time on different streams", CWE664, Certainty::normal);
}
//---------------------------------------------------------------------------
// scanf without field width limits can crash with huge input data
//---------------------------------------------------------------------------
void CheckIOImpl::invalidScanf()
{
if (!mSettings.severity.isEnabled(Severity::warning) && !mSettings.isPremiumEnabled("invalidscanf"))
return;
logChecker("CheckIO::invalidScanf");
const SymbolDatabase * const symbolDatabase = mTokenizer->getSymbolDatabase();
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token *tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
const Token *formatToken = nullptr;
if (Token::Match(tok, "scanf|vscanf ( %str% ,"))
formatToken = tok->tokAt(2);
else if (Token::Match(tok, "sscanf|vsscanf|fscanf|vfscanf (")) {
const Token* nextArg = tok->tokAt(2)->nextArgument();
if (nextArg && nextArg->tokType() == Token::eString)
formatToken = nextArg;
else
continue;
} else
continue;
bool format = false;
// scan the string backwards, so we do not need to keep states
const std::string &formatstr(formatToken->str());
for (std::size_t i = 1; i < formatstr.length(); i++) {
if (formatstr[i] == '%')
format = !format;
else if (!format)
continue;
else if (std::isdigit(formatstr[i]) || formatstr[i] == '*') {
format = false;
}
else if (std::isalpha(static_cast<unsigned char>(formatstr[i])) || formatstr[i] == '[') {
if (formatstr[i] == 's' || formatstr[i] == '[' || formatstr[i] == 'S' || (formatstr[i] == 'l' && formatstr[i+1] == 's')) // #3490 - field width limits are only necessary for string input
invalidScanfError(tok);
format = false;
}
}
}
}
}
void CheckIOImpl::invalidScanfError(const Token *tok)
{
const std::string fname = (tok ? tok->str() : std::string("scanf"));
reportError(tok, Severity::warning,
"invalidscanf", fname + "() without field width limits can crash with huge input data.\n" +
fname + "() without field width limits can crash with huge input data. Add a field width "
"specifier to fix this problem.\n"
"\n"
"Sample program that can crash:\n"
"\n"
"#include <stdio.h>\n"
"int main()\n"
"{\n"
" char c[5];\n"
" scanf(\"%s\", c);\n"
" return 0;\n"
"}\n"
"\n"
"Typing in 5 or more characters may make the program crash. The correct usage "
"here is 'scanf(\"%4s\", c);', as the maximum field width does not include the "
"terminating null byte.\n"
"Source: http://linux.die.net/man/3/scanf\n"
"Source: http://www.opensource.apple.com/source/xnu/xnu-1456.1.26/libkern/stdio/scanf.c",
CWE119, Certainty::normal);
}
static const Token* findFileReadCall(const Token *start, const Token *end, int varid)
{
const Token* found = Token::findmatch(start, "fgets|fgetc|getc|fread|fscanf (", end);
while (found) {
const std::vector<const Token*> args = getArguments(found);
if (!args.empty()) {
const bool match = (found->str() == "fscanf")
? args.front()->varId() == varid
: args.back()->varId() == varid;
if (match)
return found;
}
found = Token::findmatch(found->next(), "fgets|fgetc|getc|fread|fscanf (", end);
}
return nullptr;
}
void CheckIOImpl::checkWrongfeofUsage()
{
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
logChecker("CheckIO::checkWrongfeofUsage");
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token *tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
// TODO: Handle for loops
if (!Token::Match(tok, "while ( ! feof ( %var% )"))
continue;
// Bail out if we cannot identify file pointer
const int fpVarId = tok->tokAt(5)->varId();
if (fpVarId == 0)
continue;
const Token *endCond = tok->linkAt(1);
const Token *bodyStart;
const Token *bodyEnd;
if (Token::simpleMatch(tok->previous(), "}") && tok->previous()->scope()->type == ScopeType::eDo) {
bodyEnd = tok->previous();
bodyStart = bodyEnd->link();
} else {
if (!Token::simpleMatch(endCond, ") {"))
continue;
bodyEnd = endCond->linkAt(1);
bodyStart = endCond->next();
}
// Bail out if the loop contains control flow (too complex to analyze)
if (Token::findmatch(bodyStart, "return|break|goto|continue|throw", bodyEnd))
continue;
// Bail out if fp is used outside of known file I/O functions.
// If it is passed to an unknown function, reads may occur there.
bool fpUsedElsewhere = false;
for (const Token *t = bodyStart->next(); t && t != bodyEnd; t = t->next()) {
if (t->varId() != fpVarId)
continue;
const Token *p = t->astParent();
while (p && p->str() == ",")
p = p->astParent();
if (!p || !Token::Match(p->astOperand1(), "fgets|fgetc|getc|fread|fscanf|fprintf|fwrite|fputs|fputc|putc")) {
fpUsedElsewhere = true;
break;
}
}
if (fpUsedElsewhere)
continue;
// No file read call in the loop: feof can never become true inside it
const Token *loopFileReadCallTok = findFileReadCall(bodyStart, bodyEnd, fpVarId);
if (!loopFileReadCallTok) {
// TODO: Warn about infinite loop
continue;
}
// Find last file read
const Token *lastLoopFileReadCallTok = loopFileReadCallTok;
while (loopFileReadCallTok) {
lastLoopFileReadCallTok = loopFileReadCallTok;
loopFileReadCallTok = findFileReadCall(lastLoopFileReadCallTok->next(), bodyEnd, fpVarId);
}
// Warn if the destination of the last file read is used after the call before bodyEnd.
// If it is not, the stale buffer is never accessed on the extra iteration at EOF.
if (lastLoopFileReadCallTok->str() == "fgetc" || lastLoopFileReadCallTok->str() == "getc") {
// Warn if the return value feeds into an expression (astParent of the call node)
if (lastLoopFileReadCallTok->astParent() && lastLoopFileReadCallTok->astParent()->astParent())
wrongfeofUsage(getCondTok(tok));
} else {
const std::vector<const Token*> args = getArguments(lastLoopFileReadCallTok);
// Collect destination varIds
std::vector<nonneg int> destVarIds;
if (lastLoopFileReadCallTok->str() == "fscanf") {
// args[0]=fp, args[1]=format, args[2+]=destinations (typically &var)
for (std::size_t i = 2; i < args.size(); ++i) {
const Token *destTok = Token::Match(args[i], "& %var%") ? args[i]->next() : args[i];
if (destTok->varId() != 0)
destVarIds.push_back(destTok->varId());
}
} else {
// Handle fgets, fread
// First argument is the destination buffer
if (!args.empty() && args.front()->varId() != 0)
destVarIds.push_back(args.front()->varId());
}
// Search for any destination use between this call's ';' and endBody
const Token *semiColonTok = lastLoopFileReadCallTok->linkAt(1)->next();
for (const Token *t = semiColonTok; t && t != bodyEnd; t = t->next()) {
if (std::find(destVarIds.begin(), destVarIds.end(), t->varId()) != destVarIds.end()) {
wrongfeofUsage(getCondTok(tok));
break;
}
}
}
}
}
}
void CheckIOImpl::wrongfeofUsage(const Token * tok)
{
reportError(tok, Severity::warning,
"wrongfeofUsage",
"Using feof() as a loop condition causes the last line to be processed twice.\n"
"feof() returns true only after a read has failed due to end-of-file, so the loop "
"body executes once more after the last successful read. Check the return value of "
"the read function instead (e.g. fgets, fread, fscanf).");
}
//---------------------------------------------------------------------------
// printf("%u", "xyz"); // Wrong argument type
// printf("%u%s", 1); // Too few arguments
// printf("", 1); // Too much arguments
//---------------------------------------------------------------------------
static bool findFormat(nonneg int arg, const Token *firstArg,
const Token *&formatStringTok, const Token *&formatArgTok)
{
const Token* argTok = firstArg;
for (int i = 0; i < arg && argTok; ++i)
argTok = argTok->nextArgument();
if (Token::Match(argTok, "%str% [,)]")) {
formatArgTok = argTok->nextArgument();
formatStringTok = argTok;
return true;
}
if (Token::Match(argTok, "%var% [,)]") &&
argTok->variable() &&
Token::Match(argTok->variable()->typeStartToken(), "char|wchar_t") &&
(argTok->variable()->isPointer() ||
(argTok->variable()->dimensions().size() == 1 &&
argTok->variable()->dimensionKnown(0) &&
argTok->variable()->dimension(0) != 0))) {
formatArgTok = argTok->nextArgument();
if (!argTok->values().empty()) {
const auto value = std::find_if(
argTok->values().cbegin(), argTok->values().cend(), std::mem_fn(&ValueFlow::Value::isTokValue));
if (value != argTok->values().cend() && value->isTokValue() && value->tokvalue &&
value->tokvalue->tokType() == Token::eString) {
formatStringTok = value->tokvalue;
}
}
return true;
}
return false;
}
// Utility function returning whether iToTest equals iTypename or iOptionalPrefix+iTypename
static inline bool typesMatch(const std::string& iToTest, const std::string& iTypename, const std::string& iOptionalPrefix = "std::")
{
return (iToTest == iTypename) || (iToTest == iOptionalPrefix + iTypename);
}
void CheckIOImpl::checkWrongPrintfScanfArguments()
{
const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
const bool isWindows = mSettings.platform.isWindows();
logChecker("CheckIO::checkWrongPrintfScanfArguments");
for (const Scope * scope : symbolDatabase->functionScopes) {
for (const Token *tok = scope->bodyStart->next(); tok != scope->bodyEnd; tok = tok->next()) {
if (!tok->isName()) continue;
const Token* argListTok = nullptr; // Points to first va_list argument
const Token* formatStringTok = nullptr; // Points to format string token
bool scan = false;
bool scanf_s = false;
int formatStringArgNo = -1;
if (tok->strAt(1) == "(" && mSettings.library.formatstr_function(tok)) {
formatStringArgNo = mSettings.library.formatstr_argno(tok);
scan = mSettings.library.formatstr_scan(tok);
scanf_s = mSettings.library.formatstr_secure(tok);
}
if (formatStringArgNo >= 0) {
// formatstring found in library. Find format string and first argument belonging to format string.
if (!findFormat(formatStringArgNo, tok->tokAt(2), formatStringTok, argListTok))
continue;
} else if (Token::simpleMatch(tok, "swprintf (")) {
if (Token::Match(tok->tokAt(2)->nextArgument(), "%str%")) {
// Find third parameter and format string
if (!findFormat(1, tok->tokAt(2), formatStringTok, argListTok))
continue;
} else {
// Find fourth parameter and format string
if (!findFormat(2, tok->tokAt(2), formatStringTok, argListTok))
continue;
}
} else if (isWindows && Token::Match(tok, "sprintf_s|swprintf_s (")) {
// template <size_t size> int sprintf_s(char (&buffer)[size], const char *format, ...);
if (findFormat(1, tok->tokAt(2), formatStringTok, argListTok)) {
if (!formatStringTok)
continue;
}
// int sprintf_s(char *buffer, size_t sizeOfBuffer, const char *format, ...);
else if (findFormat(2, tok->tokAt(2), formatStringTok, argListTok)) {
if (!formatStringTok)
continue;
}
} else if (isWindows && Token::Match(tok, "_snprintf_s|_snwprintf_s (")) {
// template <size_t size> int _snprintf_s(char (&buffer)[size], size_t count, const char *format, ...);
if (findFormat(2, tok->tokAt(2), formatStringTok, argListTok)) {
if (!formatStringTok)
continue;
}
// int _snprintf_s(char *buffer, size_t sizeOfBuffer, size_t count, const char *format, ...);
else if (findFormat(3, tok->tokAt(2), formatStringTok, argListTok)) {
if (!formatStringTok)
continue;
}
} else {
continue;
}
if (!formatStringTok)
continue;
checkFormatString(tok, formatStringTok, argListTok, scan, scanf_s);
}
}
}
void CheckIOImpl::checkFormatString(const Token * const tok,
const Token * const formatStringTok,
const Token * argListTok,
const bool scan,
const bool scanf_s)
{
const bool isWindows = mSettings.platform.isWindows();
const bool printWarning = mSettings.severity.isEnabled(Severity::warning);
const std::string &formatString = formatStringTok->str();
// Count format string parameters..
int numFormat = 0;
int numSecure = 0;
bool percent = false;
const Token* argListTok2 = argListTok;
std::set<int> parameterPositionsUsed;
for (auto i = formatString.cbegin(); i != formatString.cend(); ++i) {
if (*i == '%') {
percent = !percent;
} else if (percent && *i == '[') {
while (i != formatString.cend()) {
if (*i == ']') {
numFormat++;
if (argListTok)
argListTok = argListTok->nextArgument();
percent = false;
break;
}
++i;
}
if (scanf_s) {
numSecure++;
if (argListTok) {
argListTok = argListTok->nextArgument();
}
}
if (i == formatString.cend())
break;
} else if (percent) {
percent = false;
bool _continue = false;
bool skip = false;
std::string width;
int parameterPosition = 0;
bool hasParameterPosition = false;
while (i != formatString.cend() && *i != '[' && !std::isalpha(static_cast<unsigned char>(*i))) {
if (*i == '*') {
skip = true;
if (scan)
_continue = true;
else {
numFormat++;
if (argListTok)
argListTok = argListTok->nextArgument();
}
} else if (std::isdigit(*i)) {
width += *i;
} else if (*i == '$') {
parameterPosition = strToInt<int>(width);
hasParameterPosition = true;
width.clear();
}
++i;
}
auto bracketBeg = formatString.cend();
if (i != formatString.cend() && *i == '[') {
bracketBeg = i;
while (i != formatString.cend()) {
if (*i == ']')
break;
++i;
}
if (scanf_s && !skip) {
if (argListTok) {
argListTok = argListTok->nextArgument();
}
}
}
if (i == formatString.cend())
break;
if (_continue)
continue;
if (scan || *i != 'm') { // %m is a non-standard extension that requires no parameter on print functions.
++numFormat;
// Handle parameter positions (POSIX extension) - Ticket #4900
if (hasParameterPosition) {
if (parameterPositionsUsed.find(parameterPosition) == parameterPositionsUsed.end())
parameterPositionsUsed.insert(parameterPosition);
else // Parameter already referenced, hence don't consider it a new format
--numFormat;
}
// Perform type checks
ArgumentInfo argInfo(argListTok, mSettings, mTokenizer->isCPP());
if ((argInfo.typeToken && !argInfo.isLibraryType(mSettings.library)) || *i == ']') {
if (scan) {
std::string specifier;
bool done = false;
while (!done) {
switch (*i) {
case 's':
case ']': // charset
specifier += (*i == 's' || bracketBeg == formatString.end()) ? std::string{ 's' } : std::string{ bracketBeg, i + 1 };
if (argInfo.variableInfo && argInfo.isKnownType() && argInfo.variableInfo->isArray() && (argInfo.variableInfo->dimensions().size() == 1) && argInfo.variableInfo->dimensions()[0].known) {
if (!width.empty()) {
const int numWidth = strToInt<int>(width);
if (numWidth != (argInfo.variableInfo->dimension(0) - 1))
invalidScanfFormatWidthError(tok, numFormat, numWidth, argInfo.variableInfo, specifier);
}
}
if (argListTok && argListTok->tokType() != Token::eString && argInfo.typeToken &&
argInfo.isKnownType() && argInfo.isArrayOrPointer() &&
(!Token::Match(argInfo.typeToken, "char|wchar_t") ||
argInfo.typeToken->strAt(-1) == "const")) {
if (!(argInfo.isArrayOrPointer() && argInfo.element && !argInfo.typeToken->isStandardType()))
invalidScanfArgTypeError_s(tok, numFormat, specifier, &argInfo);
}
if (scanf_s) {
numSecure++;
if (argListTok) {
argListTok = argListTok->nextArgument();
}
}
done = true;
break;
case 'c':
if (argInfo.variableInfo && argInfo.isKnownType() && argInfo.variableInfo->isArray() && (argInfo.variableInfo->dimensions().size() == 1) && argInfo.variableInfo->dimensions()[0].known) {
if (!width.empty()) {
const int numWidth = strToInt<int>(width);
if (numWidth > argInfo.variableInfo->dimension(0))
invalidScanfFormatWidthError(tok, numFormat, numWidth, argInfo.variableInfo, std::string(1, *i));
}
}
if (scanf_s) {
numSecure++;
if (argListTok) {
argListTok = argListTok->nextArgument();
}
}
done = true;
break;
case 'x':
case 'X':
case 'u':
case 'o':
specifier += *i;
if (argInfo.typeToken->tokType() == Token::eString)
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
else if (argInfo.isKnownType()) {
if (!Token::Match(argInfo.typeToken, "char|short|int|long")) {
if (argInfo.typeToken->isStandardType() || !argInfo.element)
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
} else if (!argInfo.typeToken->isUnsigned() ||
!argInfo.isArrayOrPointer() ||
argInfo.typeToken->strAt(-1) == "const") {
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
} else {
switch (specifier[0]) {
case 'h':
if (specifier[1] == 'h') {
if (argInfo.typeToken->str() != "char")
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
} else if (argInfo.typeToken->str() != "short")
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
break;
case 'l':
if (specifier[1] == 'l') {
if (argInfo.typeToken->str() != "long" || !argInfo.typeToken->isLong())
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
else if (typesMatch(argInfo.typeToken->originalName(), "size_t") ||
typesMatch(argInfo.typeToken->originalName(), "ptrdiff_t") ||
typesMatch(argInfo.typeToken->originalName(), "uintmax_t"))
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
} else if (argInfo.typeToken->str() != "long" || argInfo.typeToken->isLong())
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
else if (typesMatch(argInfo.typeToken->originalName(), "size_t") ||
typesMatch(argInfo.typeToken->originalName(), "ptrdiff_t") ||
typesMatch(argInfo.typeToken->originalName(), "uintmax_t"))
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
break;
case 'I':
if (specifier.find("I64") != std::string::npos) {
if (argInfo.typeToken->str() != "long" || !argInfo.typeToken->isLong())
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
} else if (specifier.find("I32") != std::string::npos) {
if (argInfo.typeToken->str() != "int" || argInfo.typeToken->isLong())
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
} else if (!typesMatch(argInfo.typeToken->originalName(), "size_t"))
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
break;
case 'j':
if (!typesMatch(argInfo.typeToken->originalName(), "uintmax_t"))
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
break;
case 'z':
if (!typesMatch(argInfo.typeToken->originalName(), "size_t"))
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
break;
case 't':
if (!typesMatch(argInfo.typeToken->originalName(), "ptrdiff_t"))
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
break;
case 'L':
if (argInfo.typeToken->str() != "long" || !argInfo.typeToken->isLong())
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
else if (typesMatch(argInfo.typeToken->originalName(), "size_t") ||
typesMatch(argInfo.typeToken->originalName(), "uintmax_t"))
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
break;
default:
if (argInfo.typeToken->str() != "int")
invalidScanfArgTypeError_int(tok, numFormat, specifier, &argInfo, true);
else if (typesMatch(argInfo.typeToken->originalName(), "size_t") ||
typesMatch(argInfo.typeToken->originalName(), "ptrdiff_t") ||
typesMatch(argInfo.typeToken->originalName(), "uintmax_t"))