From: HE WEI (ギカク) Date: Wed, 15 Jul 2026 13:57:11 +0000 (+0900) Subject: wifi: mwifiex: bound uAP association event IEs to the event buffer X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f0858bfc7d3cab411a447b88e3ef970e575032c9;p=thirdparty%2Fkernel%2Flinux.git wifi: mwifiex: bound uAP association event IEs to the event buffer mwifiex_process_uap_event() handles EVENT_UAP_STA_ASSOC by exposing the (re)association request IEs that the firmware copies into the event: sinfo->assoc_req_ies = &event->data[len]; len = (u8 *)sinfo->assoc_req_ies - (u8 *)&event->frame_control; sinfo->assoc_req_ies_len = le16_to_cpu(event->len) - (u16)len; event->len is supplied by the device firmware and is never validated, and the subtraction is unchecked. assoc_req_ies points into adapter->event_body[MAX_EVENT_SIZE], a fixed-size array embedded in the kmalloc()'d struct mwifiex_adapter. On the ap_11n_enabled path mwifiex_set_sta_ht_cap() walks these IEs with cfg80211_find_ie(), whose for_each_element() loop dereferences each element header. A firmware-reported event->len larger than the bytes actually received makes assoc_req_ies_len describe IEs that extend past event_body, so the walk reads out of the adapter slab object, a slab-out-of-bounds read (KASAN: slab-out-of-bounds in cfg80211_find_ie). An event->len smaller than the header instead makes the int subtraction negative, which wraps to a huge size_t when stored in assoc_req_ies_len. The same length is handed to cfg80211_new_sta(), so a more modest over-claim can also copy stale event_body bytes into the NL80211_CMD_NEW_STATION notification. A malicious or malfunctioning mwifiex device (USB/SDIO/PCIe) can deliver such an event while the interface is in AP/uAP mode. Validate event->len before use: reject a length that underflows the header or that would place the IEs outside the event_body[] buffer the event was copied into. event->len here is struct mwifiex_assoc_event.len, a payload field internal to this event, not the transport frame length, so it is validated in this handler rather than at the generic MWIFIEX_TYPE_EVENT receive path, which only sees the event cause and the transport frame length. The bound is against event_body[MAX_EVENT_SIZE] rather than the actually-received length because the transports store the event differently (USB and SDIO leave the 4-byte event header in event_skb, PCIe strips it via skb_pull), whereas event_body is the single fixed buffer all of them copy the event into. This is the event-path analogue of the receive-path bounds checks added in commit 119585281617 ("wifi: mwifiex: Fix OOB and integer underflow when rx packets"). Fixes: e568634ae7ac ("mwifiex: add AP event handling framework") Signed-off-by: HE WEI (ギカク) Reviewed-by: Francesco Dolcini Link: https://patch.msgid.link/20260715135711.34688-1-skyexpoc@gmail.com Signed-off-by: Johannes Berg --- diff --git a/drivers/net/wireless/marvell/mwifiex/uap_event.c b/drivers/net/wireless/marvell/mwifiex/uap_event.c index 679fdae0f001..ba1bdbbff687 100644 --- a/drivers/net/wireless/marvell/mwifiex/uap_event.c +++ b/drivers/net/wireless/marvell/mwifiex/uap_event.c @@ -123,11 +123,31 @@ int mwifiex_process_uap_event(struct mwifiex_private *priv) len = ETH_ALEN; if (len != -1) { + u16 evt_len = le16_to_cpu(event->len); + sinfo->assoc_req_ies = &event->data[len]; len = (u8 *)sinfo->assoc_req_ies - (u8 *)&event->frame_control; - sinfo->assoc_req_ies_len = - le16_to_cpu(event->len) - (u16)len; + + /* + * event->len is reported by the device firmware + * and is not otherwise validated. Reject a + * length that underflows the header, or that + * would place the association request IEs + * outside the fixed-size event_body[] buffer the + * event was copied into; otherwise the IE walk + * in mwifiex_set_sta_ht_cap() reads past + * event_body and out of the adapter slab object. + */ + if (evt_len < len || + (u8 *)&event->frame_control + evt_len > + adapter->event_body + MAX_EVENT_SIZE) { + mwifiex_dbg(adapter, ERROR, + "invalid STA assoc event length\n"); + kfree(sinfo); + return -1; + } + sinfo->assoc_req_ies_len = evt_len - (u16)len; } } cfg80211_new_sta(priv->netdev->ieee80211_ptr, event->sta_addr,