CVE-2024-46760

/// Technical description

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

wifi: rtw88: usb: schedule rx work after everything is set up

Right now it's possible to hit NULL pointer dereference in

rtw_rx_fill_rx_status on hw object and/or its fields because

initialization routine can start getting USB replies before

rtw_dev is fully setup.

The stack trace looks like this:

rtw_rx_fill_rx_status

rtw8821c_query_rx_desc

rtw_usb_rx_handler

...

queue_work

rtw_usb_read_port_complete

...

usb_submit_urb

rtw_usb_rx_resubmit

rtw_usb_init_rx

rtw_usb_probe

So while we do the async stuff rtw_usb_probe continues and calls

rtw_register_hw, which does all kinds of initialization (e.g.

via ieee80211_register_hw) that rtw_rx_fill_rx_status relies on.

Fix this by moving the first usb_submit_urb after everything

is set up.

For me, this bug manifested as:

[ 8.893177] rtw_8821cu 1-1:1.2: band wrong, packet dropped

[ 8.910904] rtw_8821cu 1-1:1.2: hw->conf.chandef.chan NULL in rtw_rx_fill_rx_status

becaus

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References