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==Security==
==Security==


io_uring has been noted for exposing a significant attack surface and difficulties integrating it with the [[Linux Security Modules|Linux security subsystem]].<ref>{{Cite web |url=https://lwn.net/Articles/902466/ |title=Security requirements for new kernel features |date=2022-07-28 |access-date=2023-06-16 |website=[[LWN.net]] |last=Corbet |first=Jonathan}}</ref>.
io_uring has been noted for exposing a significant attack surface and structural difficulties integrating it with the [[Linux Security Modules|Linux security subsystem]].<ref>{{Cite web |url=https://lwn.net/Articles/902466/ |title=Security requirements for new kernel features |date=2022-07-28 |access-date=2023-06-16 |website=[[LWN.net]] |last=Corbet |first=Jonathan}}</ref>


In June 2023, Google's security team reported that 60% of Linux kernel [[Exploit (computer security)|exploits]] submitted to their [[bug bounty program]] in 2022 were exploits of io_uring vulnerabilities. As a result, io_uring was disabled for apps in [[Android (operating system)|Android]], and disabled entirely in [[ChromeOS]] as well as Google servers.<ref>{{cite web |last1=Koczka |first1=Tamás |title=Learnings from kCTF VRP's 42 Linux kernel exploits submissions |url=https://security.googleblog.com/2023/06/learnings-from-kctf-vrps-42-linux.html |website=Google Online Security Blog |publisher=Google |access-date=14 June 2023 |language=en}}</ref>
In June 2023, Google's security team reported that 60% of Linux kernel [[Exploit (computer security)|exploits]] submitted to their [[bug bounty program]] in 2022 were exploits of io_uring vulnerabilities. As a result, io_uring was disabled for apps in [[Android (operating system)|Android]], and disabled entirely in [[ChromeOS]] as well as Google servers.<ref>{{cite web |last1=Koczka |first1=Tamás |title=Learnings from kCTF VRP's 42 Linux kernel exploits submissions |url=https://security.googleblog.com/2023/06/learnings-from-kctf-vrps-42-linux.html |website=Google Online Security Blog |publisher=Google |access-date=14 June 2023 |language=en}}</ref>

Revision as of 16:38, 16 June 2023

io_uring (previously known as aioring) is a Linux kernel system call interface for storage device asynchronous I/O operations addressing performance issues with similar interfaces provided by functions like read()/write() or aio_read()/aio_write() etc. for operations on data accessed by file descriptors.[1][2]: 2 

Development is ongoing, worked on primarily by Jens Axboe at Meta.[1]

Interface

It works by creating two circular buffers, called "queue rings", for storage of submission and completion of I/O requests, respectively. For storage devices, these are called the submission queue (SQ) and completion queue (CQ).[3] Keeping these buffers shared between the kernel and application helps to boost the I/O performance by eliminating the need to issue extra and expensive system calls to copy these buffers between the two.[1][4][3] According to the io_uring design paper, the SQ buffer is writable only by consumer applications, and the CQ buffer is writable only by the kernel.[1]: 3 

eBPF can be combined with io_uring.[5]

History

The kernel interface was adopted in Linux kernel version 5.1.[1][4][6] The liburing library provides an API to interact with the kernel interface easily from userspace.[1][1]: 12  The Linux kernel has supported asynchronous I/O since version 2.5, but it was seen as difficult to use and inefficient.[7] This older API only supported certain niche use cases.[8]

Security

io_uring has been noted for exposing a significant attack surface and structural difficulties integrating it with the Linux security subsystem.[9]

In June 2023, Google's security team reported that 60% of Linux kernel exploits submitted to their bug bounty program in 2022 were exploits of io_uring vulnerabilities. As a result, io_uring was disabled for apps in Android, and disabled entirely in ChromeOS as well as Google servers.[10]

References

  1. ^ a b c d e f g "Linux Kernel Getting io_uring To Deliver Fast & Efficient I/O - Phoronix". Phoronix. Retrieved 2021-03-14.{{cite web}}: CS1 maint: url-status (link)
  2. ^ Axboe, Jens (October 15, 2019). "Efficient IO with io_uring" (PDF).{{cite web}}: CS1 maint: url-status (link)
  3. ^ a b "Getting Hands-on with io_uring using Go". developers.mattermost.com. Retrieved 2021-11-20.
  4. ^ a b "The rapid growth of io_uring [LWN.net]". lwn.net. Retrieved 2021-11-20.
  5. ^ "BPF meets io_uring [LWN.net]". LWN.net. Retrieved 2023-04-17.
  6. ^ "Faster IO through io_uring | Kernel Recipes 2019". Retrieved 2021-03-14.
  7. ^ Corbet, Jonathan. "Ringing in a new asynchronous I/O API". LWN.net. Retrieved 2021-03-14.{{cite web}}: CS1 maint: url-status (link)
  8. ^ "What's new with io_uring" (PDF). Retrieved 2022-06-01.
  9. ^ Corbet, Jonathan (2022-07-28). "Security requirements for new kernel features". LWN.net. Retrieved 2023-06-16.
  10. ^ Koczka, Tamás. "Learnings from kCTF VRP's 42 Linux kernel exploits submissions". Google Online Security Blog. Google. Retrieved 14 June 2023.
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