GHSA-P2Q7-W28W-9654

Vulnerability from github – Published: 2025-12-16 15:30 – Updated: 2026-01-19 15:30
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

comedi: multiq3: sanitize config options in multiq3_attach()

Syzbot identified an issue [1] in multiq3_attach() that induces a task timeout due to open() or COMEDI_DEVCONFIG ioctl operations, specifically, in the case of multiq3 driver.

This problem arose when syzkaller managed to craft weird configuration options used to specify the number of channels in encoder subdevice. If a particularly great number is passed to s->n_chan in multiq3_attach() via it->options[2], then multiple calls to multiq3_encoder_reset() at the end of driver-specific attach() method will be running for minutes, thus blocking tasks and affected devices as well.

While this issue is most likely not too dangerous for real-life devices, it still makes sense to sanitize configuration inputs. Enable a sensible limit on the number of encoder chips (4 chips max, each with 2 channels) to stop this behaviour from manifesting.

[1] Syzbot crash: INFO: task syz.2.19:6067 blocked for more than 143 seconds. ... Call Trace: context_switch kernel/sched/core.c:5254 [inline] __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862 __schedule_loop kernel/sched/core.c:6944 [inline] schedule+0x165/0x360 kernel/sched/core.c:6959 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760 comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2868 chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414 do_dentry_open+0x953/0x13f0 fs/open.c:965 vfs_open+0x3b/0x340 fs/open.c:1097 ...

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68258"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-16T15:15:55Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: multiq3: sanitize config options in multiq3_attach()\n\nSyzbot identified an issue [1] in multiq3_attach() that induces a\ntask timeout due to open() or COMEDI_DEVCONFIG ioctl operations,\nspecifically, in the case of multiq3 driver.\n\nThis problem arose when syzkaller managed to craft weird configuration\noptions used to specify the number of channels in encoder subdevice.\nIf a particularly great number is passed to s-\u003en_chan in\nmultiq3_attach() via it-\u003eoptions[2], then multiple calls to\nmultiq3_encoder_reset() at the end of driver-specific attach() method\nwill be running for minutes, thus blocking tasks and affected devices\nas well.\n\nWhile this issue is most likely not too dangerous for real-life\ndevices, it still makes sense to sanitize configuration inputs. Enable\na sensible limit on the number of encoder chips (4 chips max, each\nwith 2 channels) to stop this behaviour from manifesting.\n\n[1] Syzbot crash:\nINFO: task syz.2.19:6067 blocked for more than 143 seconds.\n...\nCall Trace:\n \u003cTASK\u003e\n context_switch kernel/sched/core.c:5254 [inline]\n __schedule+0x17c4/0x4d60 kernel/sched/core.c:6862\n __schedule_loop kernel/sched/core.c:6944 [inline]\n schedule+0x165/0x360 kernel/sched/core.c:6959\n schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7016\n __mutex_lock_common kernel/locking/mutex.c:676 [inline]\n __mutex_lock+0x7e6/0x1350 kernel/locking/mutex.c:760\n comedi_open+0xc0/0x590 drivers/comedi/comedi_fops.c:2868\n chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414\n do_dentry_open+0x953/0x13f0 fs/open.c:965\n vfs_open+0x3b/0x340 fs/open.c:1097\n...",
  "id": "GHSA-p2q7-w28w-9654",
  "modified": "2026-01-19T15:30:33Z",
  "published": "2025-12-16T15:30:47Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68258"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/049f14557450351750f929ebfff36d849511e132"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4cde9a7e025cc09b88097c70606f6b30c22880f4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/543f4c380c2e1f35e60528df7cb54705cda7fee3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8952bc1973cd54158c35e06bfb8c29ace7375a48"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8dc2f02d3bada9247f00bfd2e5f61f68c389a0a3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ad7ed3c9c7b8408e8612697bc43a5441fe386c71"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f24c6e3a39fa355dabfb684c9ca82db579534e72"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f9ff87aac7b37d462246c46d28912d382a8e2ea6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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