Apple lower filter driver

Драйвер фильтр FS

Привет всем, есть проблемка ((
Изучаю программирование драйверов, потихоньку приходит понимание как и что работает, только вот одного понять не могу. как написать драйвер фильтр файловой системы?? теоретическую основу я понимаю и представляю как все работает, а вот практики нет (

Есть небольшой пример из книги «Уолтер Они — Использование Microsoft Windows Driver Model — 2003»
я его урезал и сделал «бесполезным». но осталась «основа».

Зачем нужна секция с 76 по 93 строчку листинга выше? за что она отвечает?
Зачем делать цикл с 60 по 101 строку? нельзя ли обойтись без зацикливания и просто прогнать?

Не могу понять, каким образом данный драйвер понимает что нужно подключится именно к стеку файловой системы а не к другому стеку, например клавиатуры?? Подозреваю что дело в .inf файле данного драйвера, поэтому его я тоже выкладываю.

Драйвер фильтр USB
Всем привет! Пробую писать фильтр запросов к USB-устройствам. Пока застрял на том этапе, что.

Драйвер-фильтр для COM порта
Всем привет и доброго времени суток! //Я надеюсь кто-нибудь сможет мне помочь Передо мной.

Драйвер Фильтр
Здрастье! В Windows Driver Kit есть исходники и описания для драйверов фильтров (как их писать на.

Драйвер-фильтр на C/C++
Нужно написать драйвер-фильтр на C/C++.Он должен создавать «виртуальный» жёсткий диск (по сути.

Источник

Installing a UMDF Filter Driver

A filter driver can support a specific device or all devices in a setup class. A lower filter driver attaches below a device’s function driver, while an upper filter attaches above a device’s function driver.

This topic describes how to install and configure a User-Mode Driver Framework (UMDF) device-specific (upper or lower) filter driver. You cannot use UMDF to write a class filter driver. This topic applies to both UMDF versions 1 and 2.

As you structure your device stack, keep in mind that the framework currently supports only one contiguous block of UMDF drivers per stack. Also, you cannot install UMDF version 1 and version 2 drivers in the same device stack.

How to install and configure your driver

A UMDF 1 filter driver should call IWDFDeviceInitialize::SetFilter from the its IDriverEntry::OnDeviceAdd callback function. Starting in UMDF version 2, your driver instead calls WdfFdoInitSetFilter.

In addition to any UMDF-specific directives your driver may specify, you must specify the UmdfService and UmdfServiceOrder directives. In this topic, we’ll specify an upper filter driver:

The drivers are added to the device stack in the order that they are listed in the UmdfServiceOrder entry. The first parameter specifies the lowest UMDF driver in the device stack. To install a lower filter driver, simply reverse the arguments for UmdfServiceOrder.

For more info about these and other UMDF-specific INF directives, see Specifying WDF Directives in INF Files.

If your driver’s device stack contains only UMDF drivers, skip this step.

If your driver’s device stack contains any drivers that are not UMDF, your INF file must include an AddReg section that specifies the reflector as an upper filter driver:

After your driver is loaded as an upper filter, it is responsible for forwarding I/O requests to the next driver in the stack. To illustrate, consider a simple pass-through driver (UMDF version 1) that is above a KMDF function driver.

First, retrieve the interface of the default I/O target (next driver in the stack). Then, format and send the request. The simplest scenario would look like this:

Источник

Lower Filter Driver

How can I install a filter driver as lower filter driver? All samples of DDK are upper filter driver. Is there any method except using INF file for doing this work? I know that lower filter drivers sit under FDO and top of BDO, but if there are more that one lower filter driver, how they are ordered? Can I put my driver at a specific location of this stack?

2 Answers 2

How can I install a filter driver as lower filter driver?

Upper and lower filter drivers are installed in much the same way — you don’t actually require an INF — you can just set values in the Registry. Of course, it depends upon which type of Filter Driver you want install, but as an example, if I want to set a lower disk class filter driver, I open up Regedit and navigate to the following key:

In here, you should see a string value called UpperFilters containing PartMgr. If you want to add a Lower Filter, simply create a LowerFilters value and set the name of your driver key to it. The GUID in the keyname is horrible, but if you scan through the Class key, you’ll see lots of GUID-named keys — the default value of each one contains a brief description of what device the key represents.

Like PartMgr and all the other drivers, you will need to create your driver key under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services with all the appropriate configuration values. If you’re not sure of the values for your driver, dump the entire HKLM\SYSTEM key to a file, install your driver normally, take a second dump of the entire HKLM\SYSTEM key and diff the dumps to see what values were put where.

Can I put my driver at a specific location of this stack?

Contrary to what anyone tells you otherwise, the answer is no. People sometimes believe that when multiple drivers are listed in the UpperFilters and LowerFilters registry values, the first one in this list gets loaded first. I’ve even witnessed this turn into «registry wars» where drivers are constantly fighting over their position in the list. It’s nonsense and you should design your driver to cope with any other driver appearing above or below you.

Источник

Apple lower filter driver

Эта статья является практическим дополнением предыдущей, где мы рассмотрели жизненный цикл IRP. Без прочтения предыдущей статьи будет трудно до конца понять материал этой. Если вы используете USB-мышь или клавиатуру у вас, к сожалению, могут возникнуть некоторые трудности (см. конец статьи).

Стек клавиатуры

Для начала совсем чуть-чуть теории о том, как функционирует стек клавиатуры.

Физическую связь клавиатуры с шиной осуществляет микроконтроллер клавиатуры Intel 8042 (или совместимый с ним). На современных компьютерах он интегрирован в чипсет материнской платы. Этот контроллер может работать в двух режимах: AT-совместимом и PS/2-совместимом. AT-клавиатуру, сейчас, наверное, уже сложно найти. Все клавиатуры уже давно являются PS/2-совместимыми или клавиатурами, подключаемыми через интерфейс USB. В PS/2-совместимом режиме микроконтроллер клавиатуры также связывает с шиной и PS/2-совместимую мышь. Всем этим хозяйством управляет функциональный драйвер i8042prt (Intel 8042 Port Driver), полный исходный код которого, можно найти в DDK (DDK\src\input\pnpi8042). Драйвер i8042prt создает два безымянных объекта «устройство» и подключает один к стеку клавиатуры, а другой к стеку мыши. В прошлой статье на рисунке 15-4 вы видели, что на машине с системой Terminal Server у клавиатуры (и у мыши тоже) имеется более одного (определяется количеством терминальных сессий) стека. На «обычной» машине клавиатурный и «мышиный» стеки выглядят примерно так:

Поверх драйвера i8042prt, точнее поверх его устройств, располагаются именованные объекты «устройство» драйверов Kbdclass и Mouclass. Имя «KeyboardClass» является базовым, и к нему добавляются индексы (0, 1 и т.д.). Базовое имя хранится в параметре реестра HKLM\SYSTEM\CurrentControlSet\Services\Kbdclass\Parameters\KeyboardDeviceBaseName и может быть также «KeyboardPort» в случае если клавиатура использует унаследованные (legacy) драйверы, хотя подробно я в этом не разбирался (см. исходный код драйвера Kbdclass). Мы будем использовать в качестве устройства-цели для подключения фильтра объект «устройство» под именем «KeyboardClass0».

Драйверы Kbdclass и Mouclass являются так называемыми драйверами класса (class drivers) и реализуют общую функциональность для всех типов клавиатур и мышей, т.е. для всего класса этих устройств. Оба эти драйвера устанавливаются как высокоуровневые драйверы фильтры и их полный исходный код также можно найти в DDK (DDK\src\input\kbdclass и DDK\src\input\mouclass, соответственно). В архиве к этой статье в каталоге SetKeyboardLeds находится простейший драйвер, зажигающий все три индикатора клавиатуры. Примерно так (т.е. через порты ввода/вывода) функциональный драйвер i8042prt управляет устройством «клавиатура». В исходном коде драйверов Kbdclass и Mouclass обращения к портам вы конечно не найдете.

Источник

Device filter driver ordering

Microsoft has developed a method of declaratively adding filters by expressing the intent of the filter, rather than the stack position, known as device filter driver ordering.

The need for device filter driver ordering

Prior to Windows 10 version 1903, the only supported way to register a device filter driver was by addition of a registry entry (using the AddReg directive). However, this method of registry manipulation does not provide the flexibility to specify at exactly which position to register a particular filter.

Filter registration using the AddReg directive simply appends the filter to the end of the filter list. This approach uses a list of values where order matters and determines where in the stack the filter is loaded.

Using a single list of ordered values is less than ideal, especially when AddReg only appends to the end, because there are negative consequences when more than one driver is adding filters to the same device.

In the scenario where there is at least one Extension INF involved, if the INFs improperly use AddReg (in other words don’t use the append flag), they could wipe out a filter added by a different INF.

Additionally, multiple Extension INF’s could be adding filters, and the relative ordering of those filters may be important; however, the Plug and Play (PnP) platform does not guarantee an installation order for the extensions. The result is that the order of the «appends» is not guaranteed.

Implementing device filter driver ordering

In order to provide a flexible declarative method to register device filters, Microsoft has developed a method of declaratively adding filters by expressing the intent of the filter, rather than the stack position. The solution provides function driver authors the ability to express in their INF an ordered set of positions (called levels) that a filter may register itself against.

In addition to a specific level, a filter can declaratively register simply as an upper or lower level filter.

The infrastructure is based on a new filter registration method to determine what order drivers are to be included in the device stack. The new method does not break compatibility for the old way of adding filters. It does, however, enable new filters to move to a more robust and flexible registration mechanism.

The method is enabled by having the base INF define an ordered list of one or more «levels». Both the base INF and any extension INFs may register a declarative filter via a new INF directive that specifies the service name and level to which the filter belongs to. Upper and lower filters each are represented by their own respective ordered list of levels.

These upper and lower filter lists are created by sorting all filter drivers by their level. The order of the filters within each level should be considered arbitrary, where no dependency may be taken on the order of filters within a particular level. In scenarios where the relative order of two filters must be guaranteed, they should be registered to different levels.

Consider the following device driver example:

The device driver’s base INF declares two upper filter levels, A and B (in that order). In the base INF’s associated Extension INF, two filters are added into each of the two levels.

The result of the installation of the device driver is a device stack order that merges the lists of filter drivers while respecting the desired positioning and ordering. The resulting device stack order ensures that any filter placed in the «A» level comes before any filter in the «B» level. However, within each level, the order is arbitrary.

As shown in the example, Filter3 could come before Filter5 or it could come after Filter5. In any case, Filter3 and Filter5 will come before the filters at the next level, «B».

When designing the series of levels that filters can be registered against, rather than creating a series of levels for the sake of ordering, the levels should be named and ordered such that they map to the intent of the filter. For instance, an I/O device may define the level Encryption, to which any encryption filter should be registered. This allows the intent of the filter to be easily understood and managed, and makes the stack more robust against breaking changes to the function driver.

Even without levels defined by the base INF, a declarative filter may register as simply upper or lower. When levels are not defined, this is logically equivalent to appending the filter to the end of the UpperFilters/LowerFilters registry value. When levels are defined, one of the levels must be marked as the default level in the base driver, and in this case the filter will be registered into that level.

Scenarios

Consider an I/O device driver that encrypts the data that is coming through the stack. A typical implementation may use a lower filter driver immediately underneath the function driver to accomplish this. In order to ensure that the encryption filter is placed at the exact position the driver author desires, they may use declarative filters as shown below:

The Base INF establishes two levels of lower filters, «Encryption» and «Monitoring» (Default). «Monitoring» (Default) in this example are the rest of the lower filters that might exist for this particular device. By explicitly placing the «Encrypt» filter driver in the «Encryption» level, the driver ensures that the resulting device stack order will put the «Encrypt» filter driver before any other lower filters and immediately following the function driver.

Let’s take the example one step further. Imagine a newer version of the driver comes out and the author has built in encryption to the function driver. This removes the need for a separate «Encrypt» filter driver. The author simply needs to remove the level that contained the «Encrypt» filter from the Base INF and when the driver updates, the stack is dynamically built again.

If a filter declares itself to be in an explicit level that does not exist, the filter does not end up in the device stack. In the example, the Base INF has been updated and even though the Extension INF remains the same, the resulting device stack excludes the «Encrypt» filter as it was not included in the Base INF’s declaration of levels.

Default filter level

To generate the final filter stack, all sources of filter information are merged into a single list. It is important to note that the merge logic is performed when creating the device stack. If a new filter is added by installing a new/updated base or extension driver, the devices will be restarted during installation and pick up a new filter list.

Some sources of filters lack any position information, namely filters added via the legacy UpperFilters/LowerFilters registry values, or through position-only declarative syntax (discussed below).

To support an effective merge when lacking position information, an additional piece of information must be defined by the Base INF: a default filter level. The default filter level is a position where filters, lacking level or position information, will be inserted.

For example, filter levels may be defined in the Base INF as:

Specifying the default level as the final level indicates that any filter that lacking position information will be appended to the filter list. Alternatively, the driver author may wish to have the stack always end with filters explicitly registered to level C:

Due to the default filter level being set to B, any additional filter without position information will be inserted between A’s filters and C’s filters.

Syntax

Registering filters

FilterLevel OR FilterPosition may be specified in one of two ways:

Option 1:

Option 2:

This can be done in both Base and Extension INF’s.

FilterName is the name of the service on the system.

Flags is currently unused and should be left empty or set to 0.

FilterSection is a section describing the filter.

A filter section must contain exactly one of the following two directives:В FilterLevel or FilterPosition.

A FilterLevel is a specific place to insert the device filter on the stack, defined by the Base INF.В Within each level, the order of the filters is arbitrary.

A FilterPosition is used in the case where the class has one specific place for third-party filters to be inserted.

Defining Filter Levels

This can only be done by a base driver.

The full declarative list of filters for a specific device can be retrieved by querying the following properties:

Legacy-equivalent filter registration

Let’s examine how to accomplish the legacy approach of trying to add an upper filter via INF:

This syntax will add «MyFilter» to the end of the list of upper filters.

With the new syntax that has been introduced, the above section is logically similar to:

This specifies that the filter «MyFilter» should be added to the list of upper filters. If the base INF has specified filter levels, using FilterPosition will register the filter in the default level for that position.

If filter levels are not specified, this filter will be registered as an upper filter in arbitrary order.

Источник