Linux Kernel up to 5.15.5 io_uring fs/io_uring.c denial of service

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.15.5. It has been rated as problematic. The affected element is an unknown function of the file fs/io_uring.c of the component io_uring. Performing a manipulation results in denial of service. This vulnerability is reported as CVE-2021-47569. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.15.5. It has been classified as problematic. This affects an unknown function of the file fs/io_uring.c of the component io_uring. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: io_uring: fail cancellation for EXITING tasks WARNING: CPU: 1 PID: 20 at fs/io_uring.c:6269 io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269 CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.16.0-rc1-syzkaller #0 Workqueue: events io_fallback_req_func RIP: 0010:io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269 Call Trace: io_req_task_link_timeout+0x6b/0x1e0 fs/io_uring.c:6886 io_fallback_req_func+0xf9/0x1ae fs/io_uring.c:1334 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 We need original task's context to do cancellations, so if it's dying and the callback is executed in a fallback mode, fail the cancellation attempt.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2021-47569. The exploitability is told to be difficult. Technical details are known, but no exploit is available.

Upgrading to version 5.15.6 eliminates this vulnerability. Applying the patch 3d2a1e68fd99/617a89484deb is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4
• 5.15.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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