[PATCH] wifi: mt76: mt7921: fix null pointer access in mt792x_mac_link_bss_remove

[Bert Karwatzki]

Am Donnerstag, dem 18.07.2024 um 16:46 -0700 schrieb sean.wang at kernel.org:
> From: Sean Wang <sean.wang at mediatek.com>
>
> Fix null pointer access in mt792x_mac_link_bss_remove.
>
> To prevent null pointer access, we should assign the vif to bss_conf in
> mt7921_add_interface. This ensures that subsequent operations on the BSS
> can properly reference the correct vif.
>
> [  T843] Call Trace:
> [  T843]  <TASK>
> [  T843]  ? __die+0x1e/0x60
> [  T843]  ? page_fault_oops+0x157/0x450
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? search_bpf_extables+0x5a/0x80
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? exc_page_fault+0x2bb/0x670
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? lock_timer_base+0x71/0x90
> [  T843]  ? asm_exc_page_fault+0x26/0x30
> [  T843]  ? mt792x_mac_link_bss_remove+0x24/0x110 [mt792x_lib]
> [  T843]  ? mt792x_remove_interface+0x6e/0x90 [mt792x_lib]
> [  T843]  ? ieee80211_do_stop+0x507/0x7e0 [mac80211]
> [  T843]  ? ieee80211_stop+0x53/0x190 [mac80211]
> [  T843]  ? __dev_close_many+0xa5/0x120
> [  T843]  ? __dev_change_flags+0x18c/0x220
> [  T843]  ? dev_change_flags+0x21/0x60
> [  T843]  ? do_setlink+0xdf9/0x11d0
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? security_sock_rcv_skb+0x33/0x50
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? __nla_validate_parse+0x61/0xd10
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? genl_done+0x53/0x80
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? netlink_dump+0x357/0x410
> [  T843]  ? __rtnl_newlink+0x5d6/0x980
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? genl_family_rcv_msg_dumpit+0xdf/0xf0
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? __kmalloc_cache_noprof+0x44/0x210
> [  T843]  ? rtnl_newlink+0x42/0x60
> [  T843]  ? rtnetlink_rcv_msg+0x152/0x3f0
> [  T843]  ? mptcp_pm_nl_dump_addr+0x180/0x180
> [  T843]  ? rtnl_calcit.isra.0+0x130/0x130
> [  T843]  ? netlink_rcv_skb+0x56/0x100
> [  T843]  ? netlink_unicast+0x199/0x290
> [  T843]  ? netlink_sendmsg+0x21d/0x490
> [  T843]  ? __sock_sendmsg+0x78/0x80
> [  T843]  ? ____sys_sendmsg+0x23f/0x2e0
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? copy_msghdr_from_user+0x68/0xa0
> [  T843]  ? ___sys_sendmsg+0x81/0xd0
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? crng_fast_key_erasure+0xbc/0xf0
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? get_random_bytes_user+0x126/0x140
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? __fdget+0xb1/0xe0
> [  T843]  ? __sys_sendmsg+0x56/0xa0
> [  T843]  ? srso_alias_return_thunk+0x5/0xfbef5
> [  T843]  ? do_syscall_64+0x5f/0x170
> [  T843]  ? entry_SYSCALL_64_after_hwframe+0x55/0x5d
> [  T843]  </TASK>
>
> Fixes: 1541d63c5fe2 ("wifi: mt76: mt7925: add mt7925_mac_link_bss_remove to remove per-link BSS")
> Reported-by: Bert Karwatzki <spasswolf at web.de>
> Closes: https://lore.kernel.org/linux-wireless/2fee61f8c903d02a900ca3188c3742c7effd102e.camel@web.de/#b
> Signed-off-by: Sean Wang <sean.wang at mediatek.com>
> ---
>  drivers/net/wireless/mediatek/mt76/mt7921/main.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/main.c b/drivers/net/wireless/mediatek/mt76/mt7921/main.c
> index 2e6268cb06c0..1bab93d049df 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7921/main.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7921/main.c
> @@ -303,6 +303,7 @@ mt7921_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
>
>  	mvif->bss_conf.mt76.omac_idx = mvif->bss_conf.mt76.idx;
>  	mvif->phy = phy;
> +	mvif->bss_conf.vif = mvif;
>  	mvif->bss_conf.mt76.band_idx = 0;
>  	mvif->bss_conf.mt76.wmm_idx = mvif->bss_conf.mt76.idx % MT76_CONNAC_MAX_WMM_SETS;
>
I've been testing this since you suggested it on 11.7.2024 and it works fine.

Tested-by: Bert Karwatzki <spasswolf at web.de>

Bert Karwatzki