GHSA-8P7C-4HWQ-MWGW

Vulnerability from github – Published: 2025-12-16 18:31 – Updated: 2025-12-16 18:31
VLAI?
Details

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

usb: gadget: udc: fix use-after-free in usb_gadget_state_work

A race condition during gadget teardown can lead to a use-after-free in usb_gadget_state_work(), as reported by KASAN:

BUG: KASAN: invalid-access in sysfs_notify+0x2c/0xd0 Workqueue: events usb_gadget_state_work

The fundamental race occurs because a concurrent event (e.g., an interrupt) can call usb_gadget_set_state() and schedule gadget->work at any time during the cleanup process in usb_del_gadget().

Commit 399a45e5237c ("usb: gadget: core: flush gadget workqueue after device removal") attempted to fix this by moving flush_work() to after device_del(). However, this does not fully solve the race, as a new work item can still be scheduled after flush_work() completes but before the gadget's memory is freed, leading to the same use-after-free.

This patch fixes the race condition robustly by introducing a 'teardown' flag and a 'state_lock' spinlock to the usb_gadget struct. The flag is set during cleanup in usb_del_gadget() before calling flush_work() to prevent any new work from being scheduled once cleanup has commenced. The scheduling site, usb_gadget_set_state(), now checks this flag under the lock before queueing the work, thus safely closing the race window.

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{
  "affected": [],
  "aliases": [
    "CVE-2025-68282"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-12-16T16:16:06Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: udc: fix use-after-free in usb_gadget_state_work\n\nA race condition during gadget teardown can lead to a use-after-free\nin usb_gadget_state_work(), as reported by KASAN:\n\n  BUG: KASAN: invalid-access in sysfs_notify+0x2c/0xd0\n  Workqueue: events usb_gadget_state_work\n\nThe fundamental race occurs because a concurrent event (e.g., an\ninterrupt) can call usb_gadget_set_state() and schedule gadget-\u003ework\nat any time during the cleanup process in usb_del_gadget().\n\nCommit 399a45e5237c (\"usb: gadget: core: flush gadget workqueue after\ndevice removal\") attempted to fix this by moving flush_work() to after\ndevice_del(). However, this does not fully solve the race, as a new\nwork item can still be scheduled *after* flush_work() completes but\nbefore the gadget\u0027s memory is freed, leading to the same use-after-free.\n\nThis patch fixes the race condition robustly by introducing a \u0027teardown\u0027\nflag and a \u0027state_lock\u0027 spinlock to the usb_gadget struct. The flag is\nset during cleanup in usb_del_gadget() *before* calling flush_work() to\nprevent any new work from being scheduled once cleanup has commenced.\nThe scheduling site, usb_gadget_set_state(), now checks this flag under\nthe lock before queueing the work, thus safely closing the race window.",
  "id": "GHSA-8p7c-4hwq-mwgw",
  "modified": "2025-12-16T18:31:32Z",
  "published": "2025-12-16T18:31:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68282"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/10014310193cf6736c1aeb4105c5f4a0818d0c65"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3b32caa73d135eea8fb9cabb45e9fc64c5a3ecb9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/baeb66fbd4201d1c4325074e78b1f557dff89b5b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c12a0c3ef815ddd67e47f9c819f9fe822fed5467"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f02a412c0a18f02f0f91b0a3d9788315a721b7fd"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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