comedi: fix race between polling and detaching (Linux Linux)

CVE-2025-38687
HIGH 7.3

En bref

Source
NVD
EPSS
EPSS 0.13 % · centile 2 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: comedi: fix race between polling and detaching syzbot reports a use-after-free in comedi in the below link, which is due to comedi gladly removing the allocated async area even though poll requests are still active on the wait_queue_head inside of it. This can cause a use-after-free when the poll entries are later triggered or removed, as the memory for the wait_queue_head has been freed. We need to check there are no tasks queued on any of the subdevices' wait queues before allowing the device to be detached by the `COMEDI_DEVCONFIG` ioctl. Tasks will read-lock `dev->attach_lock` before adding themselves to the subdevice wait queue, so fix the problem in the `COMEDI_DEVCONFIG` ioctl handler by write-locking `dev->attach_lock` before checking that all of the subdevices are safe to be deleted. This includes testing for any sleepers on the subdevices' wait queues. It remains locked until the device has been detached. This requires the `comedi_device_detach()` function to be refactored slightly, moving the bulk of it into new function `comedi_device_detach_locked()`. Note that the refactor of `comedi_device_detach()` results in `comedi_device_cancel_all()` now being called while `dev->attach_lock` is write-locked, which wasn't the case previously, but that does not matter. Thanks to Jens Axboe for diagnosing the problem and co-developing this patch.

Faiblesses (CWE)

  • CWE-362 — Situation de compétition

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1HIGH 7.3CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.3CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)
CVSS 3.1MEDIUM 4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:HNVD · nvd@nist.gov (Primary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
Linux · Linuxaffected 2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 < fe67122ba781df44a1a9716eb1dfd751321ab512 ; affected 2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 < cd4286123d6948ff638ea9cd5818ae4796d5d252 ; affected 2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 < d85fac8729c9acfd72368faff1d576ec585e5c8f ; affected 2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 < 0f989f9d05492028afd2bded4b42023c57d8a76e ; affected 2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 < 5c4a2ffcbd052c69bbf4680677d4c4eaa5a252d4 ; affected 2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 < 017198079551a2a5cf61eae966af3c4b145e1f3b
Linux · Linuxaffected 3.14 ; unaffected 0 < 3.14 ; unaffected 5.4.297 ≤ 5.4.* ; unaffected 5.10.241 ≤ 5.10.* ; unaffected 5.15.190 ≤ 5.15.* ; unaffected 6.1.149 ≤ 6.1.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD