blk-mq: pop cached request if it is usable
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.2, 6.6, 6.7, 6.12.104, 6.18.45, and 1 more
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
In the Linux kernel, the following vulnerability has been resolved: blk-mq: pop cached request if it is usable When submitting a bio to blk-mq, if the task should sleep after peeking a cached request, but before it pops it, the plug flushes and calls blk_mq_free_plug_rqs, freeing the cached_rqs. This creates a use-after-free bug. Fix this by popping the cached request before any possible blocking calls if it is suitable for use. Popping this request first holds a queue reference, so avoid any serialization races with queue freezes and can safely proceed with dispatching that request to the driver. This potentially increases a timing window from when a driver wants to freeze its queue to when requests stop being dispatched. That scenario is off the fast path though, and drivers need to appropriately handle requests during a freeze request anyway. The downside is the popped element needs to be individually freed when we performed a bio plug merge. The cached request would have had to be freed later anyway, but this patch does it inline with building the plug list instead of after flushing it.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From b0077e269f6c152e807fdac90b58caf012cdbaab · fixed in 23d8ea1e303b5f32d883757a4a707e791dbc9808; From b0077e269f6c152e807fdac90b58caf012cdbaab · fixed in 97e2d08de282ef76f84ab4ccd00f1acb3f5f999e; From b0077e269f6c152e807fdac90b58caf012cdbaab · fixed in 388468f7e7d1eab092cf2a39fdfb502e52019ec6; From b0077e269f6c152e807fdac90b58caf012cdbaab · fixed in dc278e9bf2b9513a763353e6b9cc21e0f532954e; From 6.1.72 · fixed in 6.2; From 6.5.13 · fixed in 6.6; From 6.6.3 · fixed in 6.7; From 6.1.75 · fixed in 6.2; From 6.6.14 · fixed in 6.7
- Linux Linux
6.7
- KernelLinux
From 6.7.0 · fixed in 6.12.104; From 6.13.0 · fixed in 6.18.45; From 6.19.0 · fixed in 7.0.11