drm/xe: prevent UAF around preempt fence
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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
- 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: partial
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/xe: prevent UAF around preempt fence The fence lock is part of the queue, therefore in the current design anything locking the fence should then also hold a ref to the queue to prevent the queue from being freed. However, currently it looks like we signal the fence and then drop the queue ref, but if something is waiting on the fence, the waiter is kicked to wake up at some later point, where upon waking up it first grabs the lock before checking the fence state. But if we have already dropped the queue ref, then the lock might already be freed as part of the queue, leading to uaf. To prevent this, move the fence lock into the fence itself so we don't run into lifetime issues. Alternative might be to have device level lock, or only release the queue in the fence release callback, however that might require pushing to another worker to avoid locking issues. References: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2454 References: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2342 References: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2020 (cherry picked from commit 7116c35aacedc38be6d15bd21b2fc936eed0008b)
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
Version range not reported
- Linux Linux
6.8