CVE-2024-43911

/// Technical description

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

wifi: mac80211: fix NULL dereference at band check in starting tx ba session

In MLD connection, link_data/link_conf are dynamically allocated. They

don't point to vif->bss_conf. So, there will be no chanreq assigned to

vif->bss_conf and then the chan will be NULL. Tweak the code to check

ht_supported/vht_supported/has_he/has_eht on sta deflink.

Crash log (with rtw89 version under MLO development):

[ 9890.526087] BUG: kernel NULL pointer dereference, address: 0000000000000000

[ 9890.526102] #PF: supervisor read access in kernel mode

[ 9890.526105] #PF: error_code(0x0000) - not-present page

[ 9890.526109] PGD 0 P4D 0

[ 9890.526114] Oops: 0000 [#1] PREEMPT SMP PTI

[ 9890.526119] CPU: 2 PID: 6367 Comm: kworker/u16:2 Kdump: loaded Tainted: G OE 6.9.0 #1

[ 9890.526123] Hardware name: LENOVO 2356AD1/2356AD1, BIOS G7ETB3WW (2.73 ) 11/28/2018

[ 9890.526126] Workqueue: phy2 rtw89_core_ba_work [rtw89_core]

[ 989

/// 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