Commit cfadf08a6c06ce319f6144e724f45e4923e72778

Marius Storm-Olsen <marius @trol…ech.com>
Wed Jul 01 09:51:13 GMT 2009

Tree SHA1: 672f5e0
Parent SHA1: 5ae330b (src/corelib: Remove QT_WA and non-Unicode code paths, dropping Win9x and NT support)
raw diff | raw patch

Handle application paths larger than MAX_PATH, and fix potential buffer overflow

These days we can easily get very long paths, so we should support
application paths as long as needed.

There was also a potention exploit in that if the path was MAX_PATH or
larger, the string would not be \0 terminated (see MSDN docs for
GetModuleFileName), and thus cause problems in QString::fromWCharArray().

Merge-request: 604
Reviewed-by: Marius Storm-Olsen <marius@trolltech.com>

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1741	1741	if (!d->cachedApplicationFilePath.isNull())
1742	1742	return d->cachedApplicationFilePath;
1743	1743
1744		#if defined( Q_WS_WIN )
1745		wchar_t module_name[MAX_PATH];
1746		GetModuleFileName(0, module_name, MAX_PATH);
1747		module_name[MAX_PATH] = 0;
1748		QFileInfo filePath = QString::fromWCharArray(module_name);
1749
1750		d->cachedApplicationFilePath = filePath.filePath();
	1744	#if defined(Q_WS_WIN)
	1745	d->cachedApplicationFilePath = QFileInfo(qAppFileName()).filePath();
1751	1746	return d->cachedApplicationFilePath;
1752	1747	#elif defined(Q_WS_MAC)
1753	1748	QString qAppFileName_str = qAppFileName();


76	76
77	77	Q_CORE_EXPORT QString qAppFileName() // get application file name
78	78	{
79		wchar_t buffer[MAX_PATH];
80		GetModuleFileName(0, buffer, MAX_PATH);
81		return QString::fromWCharArray(buffer);
	79	// We do MAX_PATH + 2 here, and request with MAX_PATH + 1, so we can handle all paths
	80	// up to, and including MAX_PATH size perfectly fine with string termination, as well
	81	// as easily detect if the file path is indeed larger than MAX_PATH, in which case we
	82	// need to use the heap instead. This is a work-around, since contrary to what the
	83	// MSDN documentation states, GetModuleFileName sometimes doesn't set the
	84	// ERROR_INSUFFICIENT_BUFFER error number, and we thus cannot rely on this value if
	85	// GetModuleFileName(0, buffer, MAX_PATH) == MAX_PATH.
	86	// GetModuleFileName(0, buffer, MAX_PATH + 1) == MAX_PATH just means we hit the normal
	87	// file path limit, and we handle it normally, if the result is MAX_PATH + 1, we use
	88	// heap (even if the result _might_ be exactly MAX_PATH + 1, but that's ok).
	89	wchar_t buffer[MAX_PATH + 2];
	90	DWORD v = GetModuleFileName(0, buffer, MAX_PATH + 1);
	91	buffer[MAX_PATH + 1] = 0;
	92
	93	if (v == 0)
	94	return QString();
	95	else if (v <= MAX_PATH)
	96	return QString::fromWCharArray(buffer);
	97
	98	// MAX_PATH sized buffer wasn't large enough to contain the full path, use heap
	99	wchar_t *b = 0;
	100	int i = 1;
	101	size_t size;
	102	do {
	103	++i;
	104	size = MAX_PATH * i;
	105	b = reinterpret_cast<wchar_t >(realloc(b, (size + 1) sizeof(wchar_t)));
	106	if (b)
	107	v = GetModuleFileName(NULL, b, size);
	108	} while (b && v == size);
	109
	110	if (b)
	111	*(b + size) = 0;
	112	QString res = QString::fromWCharArray(b);
	113	free(b);
	114
	115	return res;
82	116	}
83	117
84	118	void set_winapp_name()

Commit cfadf08a6c06ce319f6144e724f45e4923e72778

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