Bug 2347929 (CVE-2022-49377)

Summary: CVE-2022-49377 kernel: blk-mq: don't touch ->tagset in blk_mq_get_sq_hctx
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A use-after-free vulnerability was found in the blk_mq_get_sq_hctx function in the Linux kernel's block multiqueue (blk-mq) subsystem. This issue occurs when the function accesses the tagset pointer to determine the current default hardware context through mapping. If this access occurs after the tagset has been freed, typically after the queue cleanup process, it can lead to memory corruption. Such corruption may result in system crashes, information leaks, or privilege escalation, depending on how the freed memory is subsequently used.
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Description OSIDB Bzimport 2025-02-26 03:11:40 UTC 
In the Linux kernel, the following vulnerability has been resolved:

blk-mq: don't touch ->tagset in blk_mq_get_sq_hctx

blk_mq_run_hw_queues() could be run when there isn't queued request and
after queue is cleaned up, at that time tagset is freed, because tagset
lifetime is covered by driver, and often freed after blk_cleanup_queue()
returns.

So don't touch ->tagset for figuring out current default hctx by the mapping
built in request queue, so use-after-free on tagset can be avoided. Meantime
this way should be fast than retrieving mapping from tagset.
Comment 1 Avinash Hanwate 2025-02-26 21:42:46 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022647-CVE-2022-49377-4fdf@gregkh/T