Vulnerability CVE-2024-35811
Published: 2024-05-17

Description:
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]

 References:
https://git.kernel.org/stable/c/202c503935042272e2f9e1bb549d5f69a8681169
https://git.kernel.org/stable/c/8e3f03f4ef7c36091f46e7349096efb5a2cdb3a1
https://git.kernel.org/stable/c/bacb8c3ab86dcd760c15903fcee58169bc3026aa
https://git.kernel.org/stable/c/8c36205123dc57349b59b4f1a2301eb278cbc731
https://git.kernel.org/stable/c/0b812f706fd7090be74812101114a0e165b36744
https://git.kernel.org/stable/c/190794848e2b9d15de92d502b6ac652806904f5a
https://git.kernel.org/stable/c/6678a1e7d896c00030b31491690e8ddc9a90767a
https://git.kernel.org/stable/c/0a7591e14a8da794d0b93b5d1c6254ccb23adacb
https://git.kernel.org/stable/c/0f7352557a35ab7888bc7831411ec8a3cbe20d78
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