fkie_cve-2025-68335
Vulnerability from fkie_nvd
Published
2025-12-22 17:16
Modified
2025-12-23 14:51
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: comedi: pcl818: fix null-ptr-deref in pcl818_ai_cancel() Syzbot identified an issue [1] in pcl818_ai_cancel(), which stems from the fact that in case of early device detach via pcl818_detach(), subdevice dev->read_subdev may not have initialized its pointer to &struct comedi_async as intended. Thus, any such dereferencing of &s->async->cmd will lead to general protection fault and kernel crash. Mitigate this problem by removing a call to pcl818_ai_cancel() from pcl818_detach() altogether. This way, if the subdevice setups its support for async commands, everything async-related will be handled via subdevice's own ->cancel() function in comedi_device_detach_locked() even before pcl818_detach(). If no support for asynchronous commands is provided, there is no need to cancel anything either. [1] Syzbot crash: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] CPU: 1 UID: 0 PID: 6050 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:pcl818_ai_cancel+0x69/0x3f0 drivers/comedi/drivers/pcl818.c:762 ... Call Trace: <TASK> pcl818_detach+0x66/0xd0 drivers/comedi/drivers/pcl818.c:1115 comedi_device_detach_locked+0x178/0x750 drivers/comedi/drivers.c:207 do_devconfig_ioctl drivers/comedi/comedi_fops.c:848 [inline] comedi_unlocked_ioctl+0xcde/0x1020 drivers/comedi/comedi_fops.c:2178 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] ...
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5caa40e7c6a43e08e3574f990865127705c22861
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/877adccfacb32687b90714a27cfb09f444fdfa16
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a51f025b5038abd3d22eed2ede4cd46793d89565
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d948c53dec36dafe182631457597c49c1f1df5ea
Impacted products
Vendor Product Version


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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: pcl818: fix null-ptr-deref in pcl818_ai_cancel()\n\nSyzbot identified an issue [1] in pcl818_ai_cancel(), which stems from\nthe fact that in case of early device detach via pcl818_detach(),\nsubdevice dev-\u003eread_subdev may not have initialized its pointer to\n\u0026struct comedi_async as intended. Thus, any such dereferencing of\n\u0026s-\u003easync-\u003ecmd will lead to general protection fault and kernel crash.\n\nMitigate this problem by removing a call to pcl818_ai_cancel() from\npcl818_detach() altogether. This way, if the subdevice setups its\nsupport for async commands, everything async-related will be\nhandled via subdevice\u0027s own -\u003ecancel() function in\ncomedi_device_detach_locked() even before pcl818_detach(). If no\nsupport for asynchronous commands is provided, there is no need\nto cancel anything either.\n\n[1] Syzbot crash:\nOops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN PTI\nKASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]\nCPU: 1 UID: 0 PID: 6050 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025\nRIP: 0010:pcl818_ai_cancel+0x69/0x3f0 drivers/comedi/drivers/pcl818.c:762\n...\nCall Trace:\n \u003cTASK\u003e\n pcl818_detach+0x66/0xd0 drivers/comedi/drivers/pcl818.c:1115\n comedi_device_detach_locked+0x178/0x750 drivers/comedi/drivers.c:207\n do_devconfig_ioctl drivers/comedi/comedi_fops.c:848 [inline]\n comedi_unlocked_ioctl+0xcde/0x1020 drivers/comedi/comedi_fops.c:2178\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n..."
    }
  ],
  "id": "CVE-2025-68335",
  "lastModified": "2025-12-23T14:51:52.650",
  "metrics": {},
  "published": "2025-12-22T17:16:01.237",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5caa40e7c6a43e08e3574f990865127705c22861"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/877adccfacb32687b90714a27cfb09f444fdfa16"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a51f025b5038abd3d22eed2ede4cd46793d89565"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d948c53dec36dafe182631457597c49c1f1df5ea"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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