ghsa-7r9r-9pcc-36g7
Vulnerability from github
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: 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] ...
{
"affected": [],
"aliases": [
"CVE-2025-68335"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-22T17:16:01Z",
"severity": null
},
"details": "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": "GHSA-7r9r-9pcc-36g7",
"modified": "2025-12-22T18:30:25Z",
"published": "2025-12-22T18:30:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68335"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5caa40e7c6a43e08e3574f990865127705c22861"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/877adccfacb32687b90714a27cfb09f444fdfa16"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a51f025b5038abd3d22eed2ede4cd46793d89565"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d948c53dec36dafe182631457597c49c1f1df5ea"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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