Device driver: Difference between revisions

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imported>Kvng
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{{OS}}
{{OS}}


In the context of an [[operating system]], a '''device driver''' is a [[computer program]] that operates or controls a particular type of [[Peripheral|device]] that is attached to a [[computer]] or [[automaton]].<ref name="dev1">{{cite web|title=What is all device driver?|url=http://searchenterprisedesktop.techtarget.com/definition/device-driver|website=WhatIs.com|publisher=TechTarget|access-date=19 March 2018|archive-date=13 February 2021|archive-url=https://web.archive.org/web/20210213094525/https://searchenterprisedesktop.techtarget.com/definition/device-driver|url-status=live}}</ref> A driver provides a software [[Interface (computing)|interface]] to [[Computer hardware|hardware]] devices, enabling operating systems and other computer programs to access hardware functions without needing to know precise details about the hardware being used.
A '''device driver''' is [[software]] that operates or controls a particular type of [[Peripheral|device]] that is attached to a [[computer]].<ref name="dev1">{{cite web|title=What is all device driver?|url=http://searchenterprisedesktop.techtarget.com/definition/device-driver|website=WhatIs.com|publisher=TechTarget|access-date=19 March 2018|archive-date=13 February 2021|archive-url=https://web.archive.org/web/20210213094525/https://searchenterprisedesktop.techtarget.com/definition/device-driver|url-status=live}}</ref> A driver provides a software [[Interface (computing)|interface]] to [[Computer hardware|hardware]] devices, enabling other software to access hardware functions without needing to know precise details about the hardware.


A driver communicates with the device through the [[computer bus]] or communications subsystem to which the hardware connects. When a [[System call|calling]] program invokes a [[subroutine|routine]] in the driver, the driver issues commands to the device (drives it). Once the device sends data back to the driver, the driver may invoke routines in the original calling program.
A driver communicates with the device through the [[computer bus]] or communications subsystem to which the hardware connects. When a [[System call|calling]] program invokes a [[subroutine|routine]] in the driver, the driver issues commands to the device (drives it). Once the device sends data back to the driver, the driver may invoke routines in the original calling program.


Drivers are hardware dependent and operating-system-specific. They usually provide the [[interrupt]] handling required for any necessary asynchronous time-dependent hardware interface.<ref>{{cite book|url=https://books.google.com/books?id=sCCfRAj3aCgC&q=device+driver+hardware+dependent|title=Information Storage and Management: Storing, Managing, and Protecting Digital Information|year=2010|author=EMC Education Services|publisher=John Wiley & Sons|isbn=9780470618332|access-date=2020-11-10|archive-date=2021-02-13|archive-url=https://web.archive.org/web/20210213094529/https://books.google.com/books?id=sCCfRAj3aCgC&q=device+driver+hardware+dependent|url-status=live}}</ref>
Drivers are hardware-dependent and operating-system-specific. They usually provide the [[Interrupt handler|interrupt handling]] required for any necessary asynchronous time-dependent hardware interface.<ref>{{cite book|url=https://books.google.com/books?id=sCCfRAj3aCgC&q=device+driver+hardware+dependent|title=Information Storage and Management: Storing, Managing, and Protecting Digital Information|year=2010|author=EMC Education Services|publisher=John Wiley & Sons|isbn=9780470618332|access-date=2020-11-10|archive-date=2021-02-13|archive-url=https://web.archive.org/web/20210213094529/https://books.google.com/books?id=sCCfRAj3aCgC&q=device+driver+hardware+dependent|url-status=live}}</ref>


==Purpose==
==Purpose==
The main purpose of device drivers is to provide abstraction by acting as a translator between a hardware device and the applications or [[operating system]]s that use it.<ref name="dev1"/> Programmers can write higher-level application code independently of whatever specific hardware the end-user is using.
The main purpose of device drivers is to provide [[hardware abstraction]] by acting as a translator between a hardware device and the applications or [[operating system]]s that use it.<ref name="dev1"/> Programmers can write higher-level application code independently of whatever specific hardware the end-user is using.
For example, a high-level application for interacting with a [[serial port]] may simply have two functions for "send data" and "receive data". At a lower level, a device driver implementing these functions would communicate to the particular serial port controller installed on a user's computer. The commands needed to control a [[16550 UART]] are much different from the commands needed to control an [[FTDI]] serial port converter, but each hardware-specific device driver [[Abstraction (computer science)|abstracts]] these details into the same (or similar) software interface.
 
For example, a high-level application for interacting with a [[serial port]] may simply have two functions for ''send data'' and ''receive data''. At a lower level, a device driver implementing these functions would communicate with the particular serial port controller installed on a user's computer. The commands needed to control a [[16550 UART]] are much different from the commands needed to control a [[USB-to-serial adapter]], but each hardware-specific device driver abstracts these details into the same (or similar) software interface.


==Development==
==Development==
Writing a device driver requires an in-depth understanding of how the hardware and the software works for a given [[Computing platform|platform]] function. Because drivers require low-level access to hardware functions in order to operate, drivers typically operate in a highly [[privilege (computing)|privilege]]d environment and can cause system operational issues if something goes wrong. In contrast, most user-level software on modern operating systems can be stopped without greatly affecting the rest of the system. Even drivers executing in [[user mode]] can crash a system if the device is [[Erroneous program|erroneously programmed]]. These factors make it more difficult and dangerous to diagnose problems.<ref>{{cite book|url=https://books.google.com/books?id=9aFQAAAAMAAJ&q=writing+a+device+driver|title=Writing device drivers: tutorial and reference|year=1995|author=Burke, Timothy|publisher=Digital Press|isbn=9781555581411|access-date=2016-08-05|archive-date=2021-01-26|archive-url=https://web.archive.org/web/20210126050637/https://books.google.com/books?id=9aFQAAAAMAAJ&q=writing+a+device+driver|url-status=live}}</ref>
Writing a device driver requires an in-depth understanding of how the hardware and the software work for a given [[Computing platform|platform]] function. Because drivers require low-level access to hardware functions in order to operate, drivers typically operate in a highly [[privilege (computing)|privileged]] environment and can cause system operational issues if something goes wrong. In contrast, misbehavior in most user-level software on modern operating systems can be stopped without greatly affecting the rest of the system. Even drivers executing in [[user mode]] can crash a system if the device is [[Erroneous program|erroneously programmed]]. These factors make it more difficult and dangerous to diagnose problems.<ref>{{cite book|url=https://books.google.com/books?id=9aFQAAAAMAAJ&q=writing+a+device+driver|title=Writing device drivers: tutorial and reference|year=1995|author=Burke, Timothy|publisher=Digital Press|isbn=9781555581411|access-date=2016-08-05|archive-date=2021-01-26|archive-url=https://web.archive.org/web/20210126050637/https://books.google.com/books?id=9aFQAAAAMAAJ&q=writing+a+device+driver|url-status=live}}</ref>


The task of writing drivers thus usually falls to [[software engineer]]s or [[computer engineer]]s who work for hardware-development companies. This is because they have better information than most outsiders about the design of their hardware. Moreover, it was traditionally considered in the hardware [[manufacturer]]'s interest to guarantee that their clients can use their hardware in an optimal way. Typically, the [[Logical Device Driver]] (LDD) is written by the operating system vendor, while the [[Physical Device Driver]] (PDD) is implemented by the device vendor. However, in recent years, non-vendors have written numerous device drivers for proprietary devices, mainly for use with [[free and open source]] operating systems. In such cases, it is important that the hardware manufacturer provide information on how the device communicates. Although this information can instead be learned by [[reverse engineering]], this is much more difficult with hardware than it is with software.
The task of writing drivers thus usually falls to [[software engineer|software]] or [[computer engineer]]s who work for hardware-development companies. This is because, as employees, they have better information than most outsiders about the design of the hardware. Moreover, it was traditionally considered in the hardware [[manufacturer]]'s interest to guarantee that their clients can use their hardware in an optimal way. Typically, the [[hardware abstraction]] portion of the driver is written by the operating system vendor, while the lower-level physical device access portion is implemented by the device vendor. However, in recent years, non-vendors have written numerous device drivers for proprietary devices, mainly for use with [[free and open source]] operating systems. In such cases, it is important that the hardware manufacturer provide information on how the device communicates. Although this information can instead be learned by [[reverse engineering]], this is much more difficult with hardware than it is with software.


[[Microsoft Windows|Windows]] uses a combination of driver and minidriver, where the full class/port driver is provided with the operating system, and miniclass/miniport drivers are developed by vendors and implement hardware- or function-specific subset of the full driver stack.<ref>{{cite web |url=https://docs.microsoft.com/en-us/windows-hardware/drivers/gettingstarted/choosing-a-driver-model |title=Choosing a driver model |publisher=Microsoft |access-date=2021-03-30}}</ref> Miniport model is used by [[Network Driver Interface Specification#Specification|NDIS]],  [[Windows Driver Model#Object-oriented driver stack|WDM]], [[Windows Display Driver Model|WDDM]], [[WaveRT]], [[StorPort]], [[Windows Image Acquisition|WIA]], and [[Human Interface Device|HID]] drivers; each of them uses device-specific APIs and still requires the developer to handle tedious device management tasks.
[[Windows]] uses a combination of driver and minidriver, where the full class/port driver is provided with the operating system, and miniclass/miniport drivers are developed by vendors and implement hardware- or function-specific subset of the full driver stack.<ref>{{cite web |url=https://docs.microsoft.com/en-us/windows-hardware/drivers/gettingstarted/choosing-a-driver-model |title=Choosing a driver model |publisher=Microsoft |access-date=2021-03-30}}</ref> Miniport model is used by [[Network Driver Interface Specification#Specification|NDIS]],  [[Windows Driver Model#Object-oriented driver stack|WDM]], [[WDDM]], [[WaveRT]], [[StorPort]], [[Windows Image Acquisition|WIA]], and [[Human Interface Device|HID]] drivers; each of them uses device-specific APIs and still requires the developer to handle device management tasks.


[[Microsoft]] has attempted to reduce system instability due to poorly written device drivers by creating a new framework for driver development, called [[Windows Driver Frameworks]] (WDF). This includes [[User-Mode Driver Framework]] (UMDF) that encourages development of certain types of drivers—primarily those that implement a [[message-based protocol]] for communicating with their devices—as user-mode drivers. If such drivers malfunction, they do not cause system instability. The [[Kernel-Mode Driver Framework]] (KMDF) model continues to allow development of kernel-mode device drivers but attempts to provide standard implementations of functions that are known to cause problems, including cancellation of I/O operations, power management, and plug-and-play device support.
[[Microsoft]] has attempted to reduce system instability due to poorly written device drivers by creating a new framework for driver development, called [[Windows Driver Frameworks]] (WDF). This includes [[User-Mode Driver Framework]] (UMDF) that encourages development of certain types of drivers—primarily those that implement a [[message-based protocol]] for communicating with their devices—as user-mode drivers. If such drivers malfunction, they do not cause system instability. The [[Kernel-Mode Driver Framework]] (KMDF) model continues to allow development of kernel-mode device drivers but attempts to provide standard implementations of functions that are known to cause problems, including cancellation of I/O operations, power management, and plug-and-play device support.
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[[Apple Inc.|Apple]] has an open-source framework for developing drivers on [[macOS]], called I/O Kit.
[[Apple Inc.|Apple]] has an open-source framework for developing drivers on [[macOS]], called I/O Kit.


In [[Linux kernel|Linux]] environments, programmers can build device drivers as parts of the [[Linux kernel|kernel]], separately as loadable [[loadable kernel module|module]]s, or as user-mode drivers (for certain types of devices where kernel interfaces exist, such as for USB devices). [[Makedev]] includes a list of the devices in Linux, including ttyS (terminal), lp ([[parallel port]]), hd (disk), loop, and sound (these include [[Sound card mixer|mixer]], [[Music sequencer|sequencer]], [[Digital signal processor|dsp]], and audio).<ref>{{cite web
In Linux environments, programmers can build device drivers as parts of the [[Linux kernel|kernel]], separately as loadable [[loadable kernel module|module]]s, or as user-mode drivers for certain types of devices where kernel interfaces exist, such as for USB devices. [[Makedev]] includes a list of the devices in Linux, including ttyS (terminal), lp ([[parallel port]]), hd (disk), loop, and sound (these include [[Sound card mixer|mixer]], [[Music sequencer|sequencer]], [[Digital signal processor|dsp]], and audio).<ref>{{cite web
  | url = http://linux.about.com/od/commands/l/blcmdl8_MAKEDEV.htm
  | url = http://linux.about.com/od/commands/l/blcmdl8_MAKEDEV.htm
  | title = MAKEDEV&nbsp;— Linux Command&nbsp;— Unix Command
  | title = MAKEDEV&nbsp;— Linux Command&nbsp;— Unix Command
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==Privilege levels==
==Privilege levels==
Depending on the operating system, device drivers may be permitted to run at various different [[Privilege_(computing)|privilege levels]]. The choice of which level of privilege the drivers are in is largely decided by the type of [[Kernel (operating system)|kernel]] an operating system uses. An operating system that uses a [[monolithic kernel]], such as the [[Linux kernel]], will typically run device drivers with the same privilege as all other kernel objects. By contrast, a system designed around [[microkernel]], such as [[Minix]], will place drivers as processes independent from the kernel but that use it for essential [[input-output]] functionalities and to pass messages between user programs and each other.<ref>{{cite book
Depending on the operating system, device drivers may be permitted to run at various different [[Privilege_(computing)|privilege levels]]. The choice of which level of privilege the drivers are in is largely decided by the type of [[Kernel (operating system)|kernel]] an operating system uses. An operating system that uses a [[monolithic kernel]], such as the [[Linux kernel]], will typically run device drivers with the same privilege as all other kernel objects. By contrast, a system designed around [[microkernel]], such as [[Minix]], will run drivers as processes independent from the kernel but that use drivers for essential [[input-output]] functions.<ref>{{cite book
|last1=Tanenbaum
|last1=Tanenbaum
|first1=Andrew
|first1=Andrew
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|edition=Seventh}}</ref>
|edition=Seventh}}</ref>


The most common mechanism for segregating memory into various privilege levels is via [[protection ring]]s. On many systems, such as those with [[x86]] and [[ARM_(processor)|ARM]] processors, switching between rings imposes a performance penalty, a factor that operating system developers and [[Embedded software|embedded software engineers]] consider when creating drivers for devices which are preferred to be run with low latency, such as [[Network interface card|network interface cards]]. The primary benefit of running a driver in user mode is improved stability since a poorly written user-mode device driver cannot crash the system by overwriting kernel memory.<ref>{{cite web
The most common mechanism for segregating memory into various privilege levels is via [[protection ring]]s. On many systems, such as those with [[x86]] and [[ARM (processor)|ARM]] processors, switching between rings imposes a performance penalty, a factor that operating system developers and [[embedded software]] engineers consider when creating drivers for devices, such as [[network interface card]]s, which prefer to run with low latency. The primary benefit of running a driver in user mode is improved stability, since a poorly written user-mode device driver cannot crash the system by overwriting kernel memory.<ref>{{cite web
  | url = http://blogs.msdn.com/iliast/archive/2006/10/10/Introduction-to-the-User_2D00_Mode-Driver-Framework.aspx
  | url = http://blogs.msdn.com/iliast/archive/2006/10/10/Introduction-to-the-User_2D00_Mode-Driver-Framework.aspx
  | title = Introduction to the User-Mode Driver Framework (UMDF)
  | title = Introduction to the User-Mode Driver Framework (UMDF)
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  | archive-url = https://web.archive.org/web/20100107015247/http://blogs.msdn.com/iliast/archive/2006/10/10/Introduction-to-the-User_2D00_Mode-Driver-Framework.aspx
  | archive-url = https://web.archive.org/web/20100107015247/http://blogs.msdn.com/iliast/archive/2006/10/10/Introduction-to-the-User_2D00_Mode-Driver-Framework.aspx
  | url-status = live
  | url-status = live
  }}</ref>
  }}</ref><!--[[User:Kvng/RTH]]-->


==Applications==
==Applications==
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** Writing to or reading from a [[device control register]]
** Writing to or reading from a [[device control register]]
** Using some higher-level interface (e.g. [[Video BIOS]])
** Using some higher-level interface (e.g. [[Video BIOS]])
** Using another lower-level device driver (e.g. file system drivers using disk drivers)
** Using another lower-level device driver (e.g., file system drivers using disk drivers)
** Simulating work with hardware, while doing something entirely different<ref name="Computer Peripherals and Interfaces">{{cite book|title=Computer Peripherals and Interfaces|date=January 2008|publisher=Technical Publications Pune|isbn=978-8184314748|pages=5–8|url=https://books.google.com/books?id=uK01xKT_mAMC&q=Simulating+work+with+hardware%2C+while+doing+something+entirely+different&pg=SA5-PA8|access-date=2016-05-03|ref=CPIbook}}{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
** Simulating work with hardware, while doing something entirely different<ref name="Computer Peripherals and Interfaces">{{cite book|title=Computer Peripherals and Interfaces|date=January 2008|publisher=Technical Publications Pune|isbn=978-8184314748|pages=5–8|url=https://books.google.com/books?id=uK01xKT_mAMC&q=Simulating+work+with+hardware%2C+while+doing+something+entirely+different&pg=SA5-PA8|access-date=2016-05-03|ref=CPIbook}}{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
* For software:
* For software:
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** Implementing a language, sometimes quite high-level (e.g. [[PostScript]])
** Implementing a language, sometimes quite high-level (e.g. [[PostScript]])


So choosing and installing the correct device drivers for given hardware is often a key component of computer system configuration.<ref>{{cite web|url=http://www.drivers.com/update/drivers-news/what-are-device-drivers-and-why-do-we-need-them/|title=What are Device Drivers and why do we need them?|date=April 17, 2015|access-date=March 19, 2018|website=drivers.com|archive-date=November 20, 2016|archive-url=https://web.archive.org/web/20161120050252/http://www.drivers.com/update/drivers-news/what-are-device-drivers-and-why-do-we-need-them/|url-status=live}}</ref>
So choosing and installing the correct device drivers for the given hardware is often a key component of computer system configuration.<ref>{{cite web|url=http://www.drivers.com/update/drivers-news/what-are-device-drivers-and-why-do-we-need-them/|title=What are Device Drivers and why do we need them?|date=April 17, 2015|access-date=March 19, 2018|website=drivers.com|archive-date=November 20, 2016|archive-url=https://web.archive.org/web/20161120050252/http://www.drivers.com/update/drivers-news/what-are-device-drivers-and-why-do-we-need-them/|url-status=live}}</ref>


==Virtual device drivers==
==Virtual device drivers==
Virtual device drivers represent a particular variant of device drivers. They are used to emulate a hardware device, particularly in [[virtual machine|virtualization]] environments, for example when a [[DOS]] program is run on a [[Microsoft Windows]] computer or when a guest operating system is run on, for example, a [[Xen]] host. Instead of enabling the guest operating system to dialog with hardware, virtual device drivers take the opposite role and emulates a piece of hardware, so that the guest operating system and its drivers running inside a [[virtual machine]] can have the illusion of accessing real hardware. Attempts by the guest operating system to access the hardware are routed to the virtual device driver in the host operating system as e.g.,&nbsp;[[function call]]s. The virtual device driver can also send simulated processor-level events like [[interrupt]]s into the virtual machine.
{{Unreferenced section|date=October 2025}}
 
Virtual device drivers represent a particular variant of device drivers. They are used to emulate a hardware device, particularly in [[virtual machine|virtualization]] environments, for example, when a guest operating system is run on a [[Xen]] host. Instead of enabling the guest operating system to dialog with hardware, virtual device drivers take the opposite role and emulate a piece of hardware, so that the guest operating system and its drivers running inside a [[virtual machine]] can have the illusion of accessing real hardware. Attempts by the guest operating system to access the hardware are routed to the virtual device driver in the host operating system, e.g., [[function call]]s. The virtual device driver can also send simulated processor-level events like [[interrupt]]s into the virtual machine.


Virtual devices may also operate in a non-virtualized environment. For example, a virtual [[network adapter]] is used with a [[virtual private network]], while a virtual [[Hard disk drive|disk]] device is used with [[iSCSI]]. A good example for virtual device drivers can be [[Daemon Tools]].
Virtual devices may also operate in a non-virtualized environment. For example, a virtual [[network adapter]] is used with a [[virtual private network]], while a virtual [[Hard disk drive|disk]] device is used with [[iSCSI]]. A good example for virtual device drivers can be [[Daemon Tools]].
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* Printers: [[CUPS]]
* Printers: [[CUPS]]
* RAIDs: CCISS<ref>{{cite web
* RAIDs: CCISS<ref>{{cite web
| url      = http://sourceforge.net/projects/cciss/
| url      = https://sourceforge.net/projects/cciss/
| title      = CCISS
| title      = CCISS
| year      = 2010
| year      = 2010
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* [[Network Driver Interface Specification]] (NDIS) – a standard [[network card]] driver API
* [[Network Driver Interface Specification]] (NDIS) – a standard [[network card]] driver API
* [[Advanced Linux Sound Architecture]] (ALSA) – the standard Linux sound-driver interface
* [[Advanced Linux Sound Architecture]] (ALSA) – the standard Linux sound-driver interface
* [[Scanner Access Now Easy]] (SANE) – a public-domain interface to raster-image scanner-hardware
* [[Scanner Access Now Easy]] (SANE) – a public-domain interface to raster-image scanner hardware
* [[Installable File System]] (IFS) – a [[filesystem API]] for IBM OS/2 and Microsoft Windows NT
* [[Installable File System]] (IFS) – a [[filesystem API]] for IBM OS/2 and Microsoft Windows NT
* [[Open Data-Link Interface]] (ODI) – network card API similar to NDIS
* [[Open Data-Link Interface]] (ODI) – network card API similar to NDIS
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A device on the [[PCI bus]] or USB is identified by two IDs which consist of two [[byte]]s each. The vendor ID identifies the vendor of the device. The device ID identifies a specific device from that manufacturer/vendor.
A device on the [[PCI bus]] or USB is identified by two IDs which consist of two [[byte]]s each. The vendor ID identifies the vendor of the device. The device ID identifies a specific device from that manufacturer/vendor.


A PCI device has often an ID pair for the main chip of the device, and also a subsystem ID pair that identifies the vendor, which may be different from the chip manufacturer.
A PCI device often has an ID pair for the main chip of the device, and also a subsystem ID pair that identifies the vendor, which may be different from the chip manufacturer.


==Security==
==Security==
Computers often have many diverse and customized device drivers running in their operating system kernel which often contain various [[Computer bug|bugs]] and [[Vulnerability (computing)|vulnerabilities]], making them a target for [[Exploit (computer security)|exploits]].<ref>{{cite book |last1=Talebi |first1=Seyed Mohammadjavad Seyed |last2=Tavakoli |first2=Hamid |last3=Zhang |first3=Hang |last4=Zhang |first4=Zheng |last5=Sani |first5=Ardalan Amiri |last6=Qian |first6=Zhiyun |title=Charm: Facilitating Dynamic Analysis of Device Drivers of Mobile Systems |url=https://www.usenix.org/conference/usenixsecurity18/presentation/talebi |access-date=5 November 2022 |pages=291–307 |language=en |date=2018 |isbn=9781939133045 |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175041/https://www.usenix.org/conference/usenixsecurity18/presentation/talebi |url-status=live }}</ref> {{anchor|BYOVD}} A ''Bring Your Own Vulnerable Driver'' (BYOVD) attacker installs any signed, old third-party driver with known vulnerabilities that allow malicious code to be inserted into the kernel.<ref name="arstechnica/microsoft-blunder">{{cite news |last1=Goodin |first1=Dan |title=How a Microsoft blunder opened millions of PCs to potent malware attacks |url=https://arstechnica.com/information-technology/2022/10/how-a-microsoft-blunder-opened-millions-of-pcs-to-potent-malware-attacks/ |access-date=8 November 2022 |work=[[Ars Technica]] |date=14 October 2022 |language=en-us |archive-date=8 November 2022 |archive-url=https://web.archive.org/web/20221108164935/https://arstechnica.com/information-technology/2022/10/how-a-microsoft-blunder-opened-millions-of-pcs-to-potent-malware-attacks/ |url-status=live }}</ref>
Computers often have many diverse and customized device drivers running in their operating system kernel, which often contain various [[Computer bug|bugs]] and [[Vulnerability (computing)|vulnerabilities]], making them a target for [[Exploit (computer security)|exploits]].<ref>{{cite book |last1=Talebi |first1=Seyed Mohammadjavad Seyed |last2=Tavakoli |first2=Hamid |last3=Zhang |first3=Hang |last4=Zhang |first4=Zheng |last5=Sani |first5=Ardalan Amiri |last6=Qian |first6=Zhiyun |title=Charm: Facilitating Dynamic Analysis of Device Drivers of Mobile Systems |url=https://www.usenix.org/conference/usenixsecurity18/presentation/talebi |access-date=5 November 2022 |pages=291–307 |language=en |date=2018 |isbn=9781939133045 |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175041/https://www.usenix.org/conference/usenixsecurity18/presentation/talebi |url-status=live }}</ref> {{anchor|BYOVD}} A ''Bring Your Own Vulnerable Driver'' (BYOVD) attacker installs any signed, old third-party driver with known vulnerabilities that allow malicious code to be inserted into the kernel.<ref name="arstechnica/microsoft-blunder">{{cite news |last1=Goodin |first1=Dan |title=How a Microsoft blunder opened millions of PCs to potent malware attacks |url=https://arstechnica.com/information-technology/2022/10/how-a-microsoft-blunder-opened-millions-of-pcs-to-potent-malware-attacks/ |access-date=8 November 2022 |work=[[Ars Technica]] |date=14 October 2022 |language=en-us |archive-date=8 November 2022 |archive-url=https://web.archive.org/web/20221108164935/https://arstechnica.com/information-technology/2022/10/how-a-microsoft-blunder-opened-millions-of-pcs-to-potent-malware-attacks/ |url-status=live }}</ref>
Drivers that may be vulnerable include those for WiFi and Bluetooth,<ref>{{cite news |last1=Ridley |first1=Jacob |title=You're going to want to update your Wi-Fi and Bluetooth drivers today |url=https://www.pcgamer.com/its-a-really-good-idea-to-update-your-wi-fi-and-bluetooth-drivers-today/ |access-date=5 November 2022 |work=PC Gamer |date=9 February 2022 |language=en |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175040/https://www.pcgamer.com/its-a-really-good-idea-to-update-your-wi-fi-and-bluetooth-drivers-today/ |url-status=live }}</ref><ref>{{cite news |title=Wireless 'BlueBorne' Attacks Target Billions of Bluetooth Devices |url=https://threatpost.com/wireless-blueborne-attacks-target-billions-of-bluetooth-devices/127921/ |access-date=5 November 2022 |work=threatpost.com |language=en |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175043/https://threatpost.com/wireless-blueborne-attacks-target-billions-of-bluetooth-devices/127921/ |url-status=live }}</ref> gaming/graphics drivers,<ref>{{cite news |last1=Spadafora |first1=Anthony |title=Installing gaming drivers might leave your PC vulnerable to cyberattacks |url=https://www.techradar.com/news/installing-gaming-drivers-might-leave-your-pc-vulnerable-to-cyberattacks |access-date=5 November 2022 |work=TechRadar |date=12 January 2022 |language=en |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175046/https://www.techradar.com/news/installing-gaming-drivers-might-leave-your-pc-vulnerable-to-cyberattacks |url-status=live }}</ref> and drivers for printers.<ref>{{cite news |title=HP patches vulnerable driver lurking in printers for 16 years |url=https://www.zdnet.com/article/hp-patches-vulnerable-printer-driver-impacting-millions-of-devices/ |access-date=5 November 2022 |work=ZDNET |language=en |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175042/https://www.zdnet.com/article/hp-patches-vulnerable-printer-driver-impacting-millions-of-devices/ |url-status=live }}</ref>
Drivers that may be vulnerable include those for WiFi and Bluetooth,<ref>{{cite news |last1=Ridley |first1=Jacob |title=You're going to want to update your Wi-Fi and Bluetooth drivers today |url=https://www.pcgamer.com/its-a-really-good-idea-to-update-your-wi-fi-and-bluetooth-drivers-today/ |access-date=5 November 2022 |work=PC Gamer |date=9 February 2022 |language=en |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175040/https://www.pcgamer.com/its-a-really-good-idea-to-update-your-wi-fi-and-bluetooth-drivers-today/ |url-status=live }}</ref><ref>{{cite news |title=Wireless 'BlueBorne' Attacks Target Billions of Bluetooth Devices |url=https://threatpost.com/wireless-blueborne-attacks-target-billions-of-bluetooth-devices/127921/ |access-date=5 November 2022 |work=threatpost.com |language=en |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175043/https://threatpost.com/wireless-blueborne-attacks-target-billions-of-bluetooth-devices/127921/ |url-status=live }}</ref> gaming/graphics drivers,<ref>{{cite news |last1=Spadafora |first1=Anthony |title=Installing gaming drivers might leave your PC vulnerable to cyberattacks |url=https://www.techradar.com/news/installing-gaming-drivers-might-leave-your-pc-vulnerable-to-cyberattacks |access-date=5 November 2022 |work=TechRadar |date=12 January 2022 |language=en |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175046/https://www.techradar.com/news/installing-gaming-drivers-might-leave-your-pc-vulnerable-to-cyberattacks |url-status=live }}</ref> and drivers for printers.<ref>{{cite news |title=HP patches vulnerable driver lurking in printers for 16 years |url=https://www.zdnet.com/article/hp-patches-vulnerable-printer-driver-impacting-millions-of-devices/ |access-date=5 November 2022 |work=ZDNET |language=en |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105175042/https://www.zdnet.com/article/hp-patches-vulnerable-printer-driver-impacting-millions-of-devices/ |url-status=live }}</ref>


Latest revision as of 17:03, 1 May 2026

This article is about device drivers for hardware. For other software drivers, see Driver (software).

Template:OS

A device driver is software that operates or controls a particular type of device that is attached to a computer.[1] A driver provides a software interface to hardware devices, enabling other software to access hardware functions without needing to know precise details about the hardware.

A driver communicates with the device through the computer bus or communications subsystem to which the hardware connects. When a calling program invokes a routine in the driver, the driver issues commands to the device (drives it). Once the device sends data back to the driver, the driver may invoke routines in the original calling program.

Drivers are hardware-dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface.[2]

Purpose

The main purpose of device drivers is to provide hardware abstraction by acting as a translator between a hardware device and the applications or operating systems that use it.[1] Programmers can write higher-level application code independently of whatever specific hardware the end-user is using.

For example, a high-level application for interacting with a serial port may simply have two functions for send data and receive data. At a lower level, a device driver implementing these functions would communicate with the particular serial port controller installed on a user's computer. The commands needed to control a 16550 UART are much different from the commands needed to control a USB-to-serial adapter, but each hardware-specific device driver abstracts these details into the same (or similar) software interface.

Development

Writing a device driver requires an in-depth understanding of how the hardware and the software work for a given platform function. Because drivers require low-level access to hardware functions in order to operate, drivers typically operate in a highly privileged environment and can cause system operational issues if something goes wrong. In contrast, misbehavior in most user-level software on modern operating systems can be stopped without greatly affecting the rest of the system. Even drivers executing in user mode can crash a system if the device is erroneously programmed. These factors make it more difficult and dangerous to diagnose problems.[3]

The task of writing drivers thus usually falls to software or computer engineers who work for hardware-development companies. This is because, as employees, they have better information than most outsiders about the design of the hardware. Moreover, it was traditionally considered in the hardware manufacturer's interest to guarantee that their clients can use their hardware in an optimal way. Typically, the hardware abstraction portion of the driver is written by the operating system vendor, while the lower-level physical device access portion is implemented by the device vendor. However, in recent years, non-vendors have written numerous device drivers for proprietary devices, mainly for use with free and open source operating systems. In such cases, it is important that the hardware manufacturer provide information on how the device communicates. Although this information can instead be learned by reverse engineering, this is much more difficult with hardware than it is with software.

Windows uses a combination of driver and minidriver, where the full class/port driver is provided with the operating system, and miniclass/miniport drivers are developed by vendors and implement hardware- or function-specific subset of the full driver stack.[4] Miniport model is used by NDIS, WDM, WDDM, WaveRT, StorPort, WIA, and HID drivers; each of them uses device-specific APIs and still requires the developer to handle device management tasks.

Microsoft has attempted to reduce system instability due to poorly written device drivers by creating a new framework for driver development, called Windows Driver Frameworks (WDF). This includes User-Mode Driver Framework (UMDF) that encourages development of certain types of drivers—primarily those that implement a message-based protocol for communicating with their devices—as user-mode drivers. If such drivers malfunction, they do not cause system instability. The Kernel-Mode Driver Framework (KMDF) model continues to allow development of kernel-mode device drivers but attempts to provide standard implementations of functions that are known to cause problems, including cancellation of I/O operations, power management, and plug-and-play device support.

Apple has an open-source framework for developing drivers on macOS, called I/O Kit.

In Linux environments, programmers can build device drivers as parts of the kernel, separately as loadable modules, or as user-mode drivers for certain types of devices where kernel interfaces exist, such as for USB devices. Makedev includes a list of the devices in Linux, including ttyS (terminal), lp (parallel port), hd (disk), loop, and sound (these include mixer, sequencer, dsp, and audio).[5]

Microsoft Windows .sys files and Linux .ko files can contain loadable device drivers. The advantage of loadable device drivers is that they can be loaded only when necessary and then unloaded, thus saving kernel memory.

Privilege levels

Depending on the operating system, device drivers may be permitted to run at various different privilege levels. The choice of which level of privilege the drivers are in is largely decided by the type of kernel an operating system uses. An operating system that uses a monolithic kernel, such as the Linux kernel, will typically run device drivers with the same privilege as all other kernel objects. By contrast, a system designed around microkernel, such as Minix, will run drivers as processes independent from the kernel but that use drivers for essential input-output functions.[6] On Windows NT, a system with a hybrid kernel, it is common for device drivers to run in either kernel-mode or user-mode.[7]

The most common mechanism for segregating memory into various privilege levels is via protection rings. On many systems, such as those with x86 and ARM processors, switching between rings imposes a performance penalty, a factor that operating system developers and embedded software engineers consider when creating drivers for devices, such as network interface cards, which prefer to run with low latency. The primary benefit of running a driver in user mode is improved stability, since a poorly written user-mode device driver cannot crash the system by overwriting kernel memory.[8]

Applications

Because of the diversity of modern hardware and operating systems, drivers operate in many different environments.[9] Drivers may interface with:

Common levels of abstraction for device drivers include:

  • For hardware:
    • Interfacing directly
    • Writing to or reading from a device control register
    • Using some higher-level interface (e.g. Video BIOS)
    • Using another lower-level device driver (e.g., file system drivers using disk drivers)
    • Simulating work with hardware, while doing something entirely different[10]
  • For software:
    • Allowing the operating system direct access to hardware resources
    • Implementing only primitives
    • Implementing an interface for non-driver software (e.g. TWAIN)
    • Implementing a language, sometimes quite high-level (e.g. PostScript)

So choosing and installing the correct device drivers for the given hardware is often a key component of computer system configuration.[11]

Virtual device drivers

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Virtual device drivers represent a particular variant of device drivers. They are used to emulate a hardware device, particularly in virtualization environments, for example, when a guest operating system is run on a Xen host. Instead of enabling the guest operating system to dialog with hardware, virtual device drivers take the opposite role and emulate a piece of hardware, so that the guest operating system and its drivers running inside a virtual machine can have the illusion of accessing real hardware. Attempts by the guest operating system to access the hardware are routed to the virtual device driver in the host operating system, e.g., function calls. The virtual device driver can also send simulated processor-level events like interrupts into the virtual machine.

Virtual devices may also operate in a non-virtualized environment. For example, a virtual network adapter is used with a virtual private network, while a virtual disk device is used with iSCSI. A good example for virtual device drivers can be Daemon Tools.

There are several variants of virtual device drivers, such as VxDs, VLMs, and VDDs.

Open source drivers

Solaris descriptions of commonly used device drivers:

  • fas: Fast/wide SCSI controller
  • hme: Fast (10/100 Mbit/s) Ethernet
  • isp: Differential SCSI controllers and the SunSwift card
  • glm: (Gigabaud Link Module[14]) UltraSCSI controllers
  • scsi: Small Computer Serial Interface (SCSI) devices
  • sf: soc+ or social Fiber Channel Arbitrated Loop (FCAL)
  • soc: SPARC Storage Array (SSA) controllers and the control device
  • social: Serial optical controllers for FCAL (soc+)

APIs

Identifiers

A device on the PCI bus or USB is identified by two IDs which consist of two bytes each. The vendor ID identifies the vendor of the device. The device ID identifies a specific device from that manufacturer/vendor.

A PCI device often has an ID pair for the main chip of the device, and also a subsystem ID pair that identifies the vendor, which may be different from the chip manufacturer.

Security

Computers often have many diverse and customized device drivers running in their operating system kernel, which often contain various bugs and vulnerabilities, making them a target for exploits.[18] A Bring Your Own Vulnerable Driver (BYOVD) attacker installs any signed, old third-party driver with known vulnerabilities that allow malicious code to be inserted into the kernel.[19] Drivers that may be vulnerable include those for WiFi and Bluetooth,[20][21] gaming/graphics drivers,[22] and drivers for printers.[23]

There is a lack of effective kernel vulnerability detection tools, especially for closed-source operating systems such as Microsoft Windows[24] where the source code of the device drivers is mostly proprietary and not available to examine,[25] and drivers often have many privileges.[26][27][28][29]

A group of security researchers considers the lack of isolation as one of the main factors undermining kernel security,[30] and published an isolation framework to protect operating system kernels, primarily the monolithic Linux kernel whose drivers they say get ~80,000 commits per year.[31][32]

page-not-found

See also

References

  1. ↑ 1.0 1.1 "What is all device driver?". WhatIs.com. TechTarget. Archived from the original on 13 February 2021. Retrieved 19 March 2018.
  2. ↑ EMC Education Services (2010). Information Storage and Management: Storing, Managing, and Protecting Digital Information. John Wiley & Sons. ISBN 9780470618332. Archived from the original on 2021-02-13. Retrieved 2020-11-10.
  3. ↑ Burke, Timothy (1995). Writing device drivers: tutorial and reference. Digital Press. ISBN 9781555581411. Archived from the original on 2021-01-26. Retrieved 2016-08-05.
  4. ↑ "Choosing a driver model". Microsoft. Retrieved 2021-03-30.
  5. ↑ "MAKEDEV — Linux Command — Unix Command". Linux.about.com. 2009-09-11. Archived from the original on 2009-04-30. Retrieved 2009-09-17.
  6. ↑ Tanenbaum, Andrew; Woodhull, Albert (2006). Operating Systems, Design and Implementation (3rd. ed.). Upper Saddle River, NJ: Pearson Pretence Hall. p. 256. ISBN 0-13-142938-8.
  7. ↑ Yosifovich, Pavel; Ionescu, Alex; Russinovich, Mark; Solomon, David (2017). Windows Internals, Part 1 (Seventh ed.). Redmond, Washington: Microsoft Press. ISBN 978-0-7356-8418-8.
  8. ↑ "Introduction to the User-Mode Driver Framework (UMDF)". Microsoft. 2006-10-10. Archived from the original on 2010-01-07. Retrieved 2008-03-04.
  9. ↑ Deborah Morley (2009). Understanding Computers 2009: Today and Tomorrow. Cengage Learning. ISBN 9780324830132. Archived from the original on 2021-06-09. Retrieved 2020-11-10.
  10. ↑ Computer Peripherals and Interfaces. Technical Publications Pune. January 2008. pp. 5–8. ISBN 978-8184314748. Retrieved 2016-05-03.[permanent dead link]
  11. ↑ "What are Device Drivers and why do we need them?". drivers.com. April 17, 2015. Archived from the original on November 20, 2016. Retrieved March 19, 2018.
  12. ↑ "CCISS". SourceForge. 2010. Archived from the original on 2010-08-21. Retrieved 2010-08-11. Drivers for the HP (previously Compaq) Smart Array controllers which provide hardware RAID capability.
  13. ↑ Russell, Steve; et al. (2003-10-21). Abbreviations and acronyms. Server Consolidation with the IBM eserver xSeries 440 and VMware ESX Serve. IBM International Technical Support Organization. p. 207. ISBN 0-7384-2684-9. Retrieved 2011-08-14.[permanent dead link]
  14. ↑ "US Patent 5969841 - Gigabaud link module with received power detect signal". PatentStorm LLC. Archived from the original on 2011-06-12. Retrieved 2009-09-08. An improved Gigabaud Link Module (GLM) is provided for performing bi-directional data transfers between a host device and a serial transfer medium.
  15. ↑ "Unified Audio Model (Windows CE 5.0)". Microsoft Developer Network. 14 September 2012. Archived from the original on 2017-06-22. Retrieved 2016-09-19.
  16. ↑ Dell US. "What are DCH drivers and why do you need to know about them? | Dell US". www.dell.com. Retrieved 2020-10-29.
  17. ↑ "dxd - dynax driver framework: Main Page". dxd.dynax.at. Archived from the original on 2016-05-29. Retrieved 2016-09-19.
  18. ↑ Talebi, Seyed Mohammadjavad Seyed; Tavakoli, Hamid; Zhang, Hang; Zhang, Zheng; Sani, Ardalan Amiri; Qian, Zhiyun (2018). Charm: Facilitating Dynamic Analysis of Device Drivers of Mobile Systems. pp. 291–307. ISBN 9781939133045. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  19. ↑ Goodin, Dan (14 October 2022). "How a Microsoft blunder opened millions of PCs to potent malware attacks". Ars Technica. Archived from the original on 8 November 2022. Retrieved 8 November 2022.
  20. ↑ Ridley, Jacob (9 February 2022). "You're going to want to update your Wi-Fi and Bluetooth drivers today". PC Gamer. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  21. ↑ "Wireless 'BlueBorne' Attacks Target Billions of Bluetooth Devices". threatpost.com. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  22. ↑ Spadafora, Anthony (12 January 2022). "Installing gaming drivers might leave your PC vulnerable to cyberattacks". TechRadar. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  23. ↑ "HP patches vulnerable driver lurking in printers for 16 years". ZDNET. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  24. ↑ Pan, Jianfeng; Yan, Guanglu; Fan, Xiaocao (2017). Digtool: A {Virtualization-Based} Framework for Detecting Kernel Vulnerabilities. USENIX Association. pp. 149–165. ISBN 9781931971409. Retrieved 5 November 2022.
  25. ↑ King, Bertel (18 June 2022). "Closed Source vs. Open Source Hardware Drivers: Why It Matters". MUO. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  26. ↑ Branscombe, Mary (7 April 2022). "How Microsoft blocks vulnerable and malicious drivers in Defender, third-party security tools and in Windows 11". TechRepublic. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  27. ↑ Goodin, Dan (5 October 2022). "No fix in sight for mile-wide loophole plaguing a key Windows defense for years". Ars Technica. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  28. ↑ Davenport, Corbin. ""Bring Your Own Vulnerable Driver" Attacks Are Breaking Windows". How-To Geek. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  29. ↑ "Windows 10 Security Alert: Vulnerabilities Found in Over 40 Drivers". BleepingComputer. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  30. ↑ "Fine-grained kernel isolation". mars-research.github.io. Archived from the original on 15 September 2022. Retrieved 15 September 2022.
  31. ↑ Fetzer, Mary. "Automatic device driver isolation protects against bugs in operating systems". Pennsylvania State University via techxplore.com. Archived from the original on 15 September 2022. Retrieved 15 September 2022.
  32. ↑ Huang, Yongzhe; Narayanan, Vikram; Detweiler, David; Huang, Kaiming; Tan, Gang; Jaeger, Trent; Burtsev, Anton (2022). "KSplit: Automating Device Driver Isolation" (PDF). Archived (PDF) from the original on 15 September 2022. Retrieved 15 September 2022.

Template:Operating systems

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