exit: prevent preemption of oopsing TASK_DEAD task
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7
- 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: exit: prevent preemption of oopsing TASK_DEAD task When an already-exiting task oopses, make_task_dead() currently calls do_task_dead() with preemption enabled. That is forbidden: do_task_dead() calls __schedule(), which has a comment saying "WARNING: must be called with preemption disabled!". If an oopsing task is preempted in do_task_dead(), between becoming TASK_DEAD and entering the scheduler explicitly, bad things happen: finish_task_switch() assumes that once the scheduler has switched away from a TASK_DEAD task, the task can never run again and its stack is no longer needed; but that assumption apparently doesn't hold if the dead task was preempted (the SM_PREEMPT case). This means that the scheduler ends up repeatedly dropping references on the dead task's stack, which can lead to use-after-free or double-free of the entire task stack; in other words, two tasks can end up running on the same stack, resulting in various kinds of memory corruption. (This does not just affect "recursively oopsing" tasks; it is enough to oops once during task exit, for example in a file_operations::release handler)
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From 7f80a2fd7db9a55894fd841915236aca611291b5 · fixed in 3d6fb8a7690c23e3213c4b008f64d89a44b98737; From 7f80a2fd7db9a55894fd841915236aca611291b5 · fixed in 640b4c00fb0e2920327435f6176cbefc3c546165; From 7f80a2fd7db9a55894fd841915236aca611291b5 · fixed in 7b2800ba5f5f77a8ee7f4cbadb19cf1264597a34; From 7f80a2fd7db9a55894fd841915236aca611291b5 · fixed in 6f49f94f3b11fe8bff1bf2a054143789e76aaf17; From 7f80a2fd7db9a55894fd841915236aca611291b5 · fixed in 9756b3db5db6c2f5eccb32dddbd88eb4c54f575e; From 7f80a2fd7db9a55894fd841915236aca611291b5 · fixed in c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891
- Linux Linux
5.17
- KernelLinux
From 5.17.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.140; From 6.7.0 · fixed in 6.12.88; From 6.13.0 · fixed in 6.18.30; From 6.19.0 · fixed in 7.0.7