wifi: ath10k: add peer map clean up for peer delete in ath10k_sta_state()
CVE: CVE-2022-50880
Component: kernel
CWE: CWE-416
Severity: Moderate
CVSS v3: 6.3/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
Release date: 2022-01-01T00:00:00+00:00

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

wifi: ath10k: add peer map clean up for peer delete in ath10k_sta_state()

When peer delete failed in a disconnect operation, use-after-free
detected by KFENCE in below log. It is because for each vdev_id and
address, it has only one struct ath10k_peer, it is allocated in
ath10k_peer_map_event(). When connected to an AP, it has more than
one HTT_T2H_MSG_TYPE_PEER_MAP reported from firmware, then the
array peer_map of struct ath10k will be set muti-elements to the
same ath10k_peer in ath10k_peer_map_event(). When peer delete failed
in ath10k_sta_state(), the ath10k_peer will be free for the 1st peer
id in array peer_map of struct ath10k, and then use-after-free happened
for the 2nd peer id because they map to the same ath10k_peer.

And clean up all peers in array peer_map for the ath10k_peer, then
user-after-free disappeared

peer map event log:
[  306.911021] wlan0: authenticate with b0:2a:43:e6:75:0e
[  306.957187] ath10k_pci 0000:01:00.0: mac vdev 0 peer create b0:2a:43:e6:75:0e (new sta) sta 1 / 32 peer 1 / 33
[  306.957395] ath10k_pci 0000:01:00.0: htt peer map vdev 0 peer b0:2a:43:e6:75:0e id 246
[  306.957404] ath10k_pci 0000:01:00.0: htt peer map vdev 0 peer b0:2a:43:e6:75:0e id 198
[  306.986924] ath10k_pci 0000:01:00.0: htt peer map vdev 0 peer b0:2a:43:e6:75:0e id 166

peer unmap event log:
[  435.715691] wlan0: deauthenticating from b0:2a:43:e6:75:0e by local choice (Reason: 3=DEAUTH_LEAVING)
[  435.716802] ath10k_pci 0000:01:00.0: mac vdev 0 peer delete b0:2a:43:e6:75:0e sta ffff990e0e9c2b50 (sta gone)
[  435.717177] ath10k_pci 0000:01:00.0: htt peer unmap vdev 0 peer b0:2a:43:e6:75:0e id 246
[  435.717186] ath10k_pci 0000:01:00.0: htt peer unmap vdev 0 peer b0:2a:43:e6:75:0e id 198
[  435.717193] ath10k_pci 0000:01:00.0: htt peer unmap vdev 0 peer b0:2a:43:e6:75:0e id 166

use-after-free log:
[21705.888627] wlan0: deauthenticating from d0:76:8f:82:be:75 by local choice (Reason: 3=DEAUTH_LEAVING)
[21713.799910] ath10k_pci 0000:01:00.0: failed to delete peer d0:76:8f:82:be:75 for vdev 0: -110
[21713.799925] ath10k_pci 0000:01:00.0: found sta peer d0:76:8f:82:be:75 (ptr 0000000000000000 id 102) entry on vdev 0 after it was supposedly removed
[21713.799968] ==================================================================
[21713.799991] BUG: KFENCE: use-after-free read in ath10k_sta_state+0x265/0xb8a [ath10k_core]
[21713.799991]
[21713.799997] Use-after-free read at 0x00000000abe1c75e (in kfence-#69):
[21713.800010]  ath10k_sta_state+0x265/0xb8a [ath10k_core]
[21713.800041]  drv_sta_state+0x115/0x677 [mac80211]
[21713.800059]  __sta_info_destroy_part2+0xb1/0x133 [mac80211]
[21713.800076]  __sta_info_flush+0x11d/0x162 [mac80211]
[21713.800093]  ieee80211_set_disassoc+0x12d/0x2f4 [mac80211]
[21713.800110]  ieee80211_mgd_deauth+0x26c/0x29b [mac80211]
[21713.800137]  cfg80211_mlme_deauth+0x13f/0x1bb [cfg80211]
[21713.800153]  nl80211_deauthenticate+0xf8/0x121 [cfg80211]
[21713.800161]  genl_rcv_msg+0x38e/0x3be
[21713.800166]  netlink_rcv_skb+0x89/0xf7
[21713.800171]  genl_rcv+0x28/0x36
[21713.800176]  netlink_unicast+0x179/0x24b
[21713.800181]  netlink_sendmsg+0x3a0/0x40e
[21713.800187]  sock_sendmsg+0x72/0x76
[21713.800192]  ____sys_sendmsg+0x16d/0x1e3
[21713.800196]  ___sys_sendmsg+0x95/0xd1
[21713.800200]  __sys_sendmsg+0x85/0xbf
[21713.800205]  do_syscall_64+0x43/0x55
[21713.800210]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[21713.800213]
[21713.800219] kfence-#69: 0x000000009149b0d5-0x000000004c0697fb, size=1064, cache=kmalloc-2k
[21713.800219]
[21713.800224] allocated by task 13 on cpu 0 at 21705.501373s:
[21713.800241]  ath10k_peer_map_event+0x7e/0x154 [ath10k_core]
[21713.800254]  ath10k_htt_t2h_msg_handler+0x586/0x1039 [ath10k_core]
[21713.800265]  ath10k_htt_htc_t2h_msg_handler+0x12/0x28 [ath10k_core]
[21713.800277]  ath10k_htc_rx_completion_handler+0x14c/0x1b5 [ath10k_core]
[21713.800283]  ath10k_pci_process_rx_cb+0x195/0x1d
---truncated---

Statement: A use-after-free vulnerability exists in the ath10k Wi-Fi driver when multiple peer IDs in peer_map[] reference the same ath10k_peer object. If firmware peer deletion fails during disconnect, the driver may free the peer while leaving stale references, leading to a UAF read in ath10k_sta_state() and a kernel crash. Exploitability is typically constrained by firmware-dependent behavior and timing, making reliable remote exploitation difficult in practice, with DoS being the most realistic outcome.

Remediation: