IEEE80211_MLE_STA_EPCS_CONTROL_LINK_ID is 0x000f, so link_id extracted from a PRIO_ACCESS ML element PER_STA_PROFILE subelement can be 0..15. sdata->link[] has IEEE80211_MLD_MAX_NUM_LINKS (15) entries (indices 0..14), making index 15 out-of-bounds. A connected WiFi 7 AP can trigger this by sending an EPCS Enable Response action frame with a PER_STA_PROFILE subelement where link_id = 15. The unsolicited-notification path (dialog_token = 0) is reachable any time EPCS is already enabled, without any prior client request. sdata->link[15] reads into the first word of sdata->activate_links_work (a wiphy_work whose embedded list_head is non-NULL after INIT_LIST_HEAD), so the NULL check on the result does not catch the invalid access. The garbage pointer is then passed to ieee80211_sta_wmm_params(), which dereferences link->sdata and crashes the kernel. The same class of bug was fixed for ieee80211_ml_reconfiguration() by commit 162d331d833d ("wifi: mac80211: bounds-check link_id in ieee80211_ml_reconfiguration"). Fixes: de86c5f60839 ("wifi: mac80211: Add support for EPCS configuration") Signed-off-by: Alexandru Hossu --- net/mac80211/mlme.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index 5b02141b0cb2..0403ebd11a4d 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -11214,6 +11214,9 @@ static void ieee80211_ml_epcs(struct ieee80211_sub_if_data *sdata, control = get_unaligned_le16(pos); link_id = control & IEEE80211_MLE_STA_EPCS_CONTROL_LINK_ID; + if (link_id >= IEEE80211_MLD_MAX_NUM_LINKS) + continue; + link = sdata_dereference(sdata->link[link_id], sdata); if (!link) continue; -- 2.50.0