CVE-2022-49943: Software Security Vulnerability Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6cpq-cwgw-5g63",
  "modified" : "2025-11-14T21:30:27Z",
  "published" : "2025-06-18T12:30:35Z",
  "aliases" : [ "CVE-2022-49943" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: gadget: Fix obscure lockdep violation for udc_mutex\n\nA recent commit expanding the scope of the udc_lock mutex in the\ngadget core managed to cause an obscure and slightly bizarre lockdep\nviolation.  In abbreviated form:\n\n======================================================\nWARNING: possible circular locking dependency detected\n5.19.0-rc7+ #12510 Not tainted\n------------------------------------------------------\nudevadm/312 is trying to acquire lock:\nffff80000aae1058 (udc_lock){+.+.}-{3:3}, at: usb_udc_uevent+0x54/0xe0\n\nbut task is already holding lock:\nffff000002277548 (kn->active#4){++++}-{0:0}, at: kernfs_seq_start+0x34/0xe0\n\nwhich lock already depends on the new lock.\n\nthe existing dependency chain (in reverse order) is:\n\n-> #3 (kn->active#4){++++}-{0:0}:\n        lock_acquire+0x68/0x84\n        __kernfs_remove+0x268/0x380\n        kernfs_remove_by_name_ns+0x58/0xac\n        sysfs_remove_file_ns+0x18/0x24\n        device_del+0x15c/0x440\n\n-> #2 (device_links_lock){+.+.}-{3:3}:\n        lock_acquire+0x68/0x84\n        __mutex_lock+0x9c/0x430\n        mutex_lock_nested+0x38/0x64\n        device_link_remove+0x3c/0xa0\n        _regulator_put.part.0+0x168/0x190\n        regulator_put+0x3c/0x54\n        devm_regulator_release+0x14/0x20\n\n-> #1 (regulator_list_mutex){+.+.}-{3:3}:\n        lock_acquire+0x68/0x84\n        __mutex_lock+0x9c/0x430\n        mutex_lock_nested+0x38/0x64\n        regulator_lock_dependent+0x54/0x284\n        regulator_enable+0x34/0x80\n        phy_power_on+0x24/0x130\n        __dwc2_lowlevel_hw_enable+0x100/0x130\n        dwc2_lowlevel_hw_enable+0x18/0x40\n        dwc2_hsotg_udc_start+0x6c/0x2f0\n        gadget_bind_driver+0x124/0x1f4\n\n-> #0 (udc_lock){+.+.}-{3:3}:\n        __lock_acquire+0x1298/0x20cc\n        lock_acquire.part.0+0xe0/0x230\n        lock_acquire+0x68/0x84\n        __mutex_lock+0x9c/0x430\n        mutex_lock_nested+0x38/0x64\n        usb_udc_uevent+0x54/0xe0\n\nEvidently this was caused by the scope of udc_mutex being too large.\nThe mutex is only meant to protect udc->driver along with a few other\nthings.  As far as I can tell, there's no reason for the mutex to be\nheld while the gadget core calls a gadget driver's ->bind or ->unbind\nroutine, or while a UDC is being started or stopped.  (This accounts\nfor link #1 in the chain above, where the mutex is held while the\ndwc2_hsotg_udc is started as part of driver probing.)\n\nGadget drivers' ->disconnect callbacks are problematic.  Even though\nusb_gadget_disconnect() will now acquire the udc_mutex, there's a\nwindow in usb_gadget_bind_driver() between the times when the mutex is\nreleased and the ->bind callback is invoked.  If a disconnect occurred\nduring that window, we could call the driver's ->disconnect routine\nbefore its ->bind routine.  To prevent this from happening, it will be\nnecessary to prevent a UDC from connecting while it has no gadget\ndriver.  This should be done already but it doesn't seem to be;\ncurrently usb_gadget_connect() has no check for this.  Such a check\nwill have to be added later.\n\nSome degree of mutual exclusion is required in soft_connect_store(),\nwhich can dereference udc->driver at arbitrary times since it is a\nsysfs callback.  The solution here is to acquire the gadget's device\nlock rather than the udc_mutex.  Since the driver core guarantees that\nthe device lock is always held during driver binding and unbinding,\nthis will make the accesses in soft_connect_store() mutually exclusive\nwith any changes to udc->driver.\n\nLastly, it turns out there is one place which should hold the\nudc_mutex but currently does not: The function_show() routine needs\nprotection while it dereferences udc->driver.  The missing lock and\nunlock calls are added.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2022-49943"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/1016fc0c096c92dd0e6e0541daac7a7868169903"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/1a065e4673cbdd9f222a05f85e17d78ea50c8d9c"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-667" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2025-06-18T11:15:21Z"
  }
}