Linux Kernel up to 5.15.10 io-wq task_work race condition

Summaryinfo

A vulnerability identified as problematic has been detected in Linux Kernel up to 5.15.10. This issue affects the function task_work of the component io-wq. The manipulation leads to an unknown weakness. This vulnerability is referenced as CVE-2021-47577. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 5.15.10. This issue affects the function task_work of the component io-wq. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: io-wq: check for wq exit after adding new worker task_work We check IO_WQ_BIT_EXIT before attempting to create a new worker, and wq exit cancels pending work if we have any. But it's possible to have a race between the two, where creation checks exit finding it not set, but we're in the process of exiting. The exit side will cancel pending creation task_work, but there's a gap where we add task_work after we've canceled existing creations at exit time. Fix this by checking the EXIT bit post adding the creation task_work. If it's set, run the same cancelation that exit does.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2021-47577 since 05/24/2024. The exploitation is known to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 5.15.11 eliminates this vulnerability. Applying the patch 4b4e5bbf9386/71a85387546e 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.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2024-1418). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• IBM InfoSphere Guardium
• Oracle Linux
• Oracle VM
• IBM Security Guardium
• RESF Rocky Linux
• Broadcom Brocade SANnav
• Dell NetWorker
• Open Source Linux Kernel
• IBM QRadar SIEM
• Dell Avamar
• IBM Storage Scale
• Juniper Junos Space
• SolarWinds Security Event Manager
• Dell PowerProtect Data Domain

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
• 5.15.6
• 5.15.7
• 5.15.8
• 5.15.9
• 5.15.10

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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