CVE-2024-35811

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

wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach

This is the candidate patch of CVE-2023-47233 :
https://nvd.nist.gov/vuln/detail/CVE-2023-47233

In brcm80211 driver,it starts with the following invoking chain
to start init a timeout worker:

->brcmf_usb_probe
  ->brcmf_usb_probe_cb
    ->brcmf_attach
      ->brcmf_bus_started
        ->brcmf_cfg80211_attach
          ->wl_init_priv
            ->brcmf_init_escan
              ->INIT_WORK(&cfg->escan_timeout_work,
		  brcmf_cfg80211_escan_timeout_worker);

If we disconnect the USB by hotplug, it will call
brcmf_usb_disconnect to make cleanup. The invoking chain is :

brcmf_usb_disconnect
  ->brcmf_usb_disconnect_cb
    ->brcmf_detach
      ->brcmf_cfg80211_detach
        ->kfree(cfg);

While the timeout woker may still be running. This will cause
a use-after-free bug on cfg in brcmf_cfg80211_escan_timeout_worker.

Fix it by deleting the timer and canceling the worker in
brcmf_cfg80211_detach.

[arend.vanspriel@broadcom.com: keep timer delete as is and cancel work just before free]