--- /dev/null
+From 8c07fa9eda13e835f3f968b2e1c9a8be3a851ff9 Mon Sep 17 00:00:00 2001
+From: Jouni Malinen <j@w1.fi>
+Date: Thu, 29 Aug 2019 11:52:04 +0300
+Subject: [PATCH] AP: Silently ignore management frame from unexpected source
+ address
+
+Do not process any received Management frames with unexpected/invalid SA
+so that we do not add any state for unexpected STA addresses or end up
+sending out frames to unexpected destination. This prevents unexpected
+sequences where an unprotected frame might end up causing the AP to send
+out a response to another device and that other device processing the
+unexpected response.
+
+In particular, this prevents some potential denial of service cases
+where the unexpected response frame from the AP might result in a
+connected station dropping its association.
+
+Signed-off-by: Jouni Malinen <j@w1.fi>
+---
+ src/ap/drv_callbacks.c | 13 +++++++++++++
+ src/ap/ieee802_11.c | 12 ++++++++++++
+ 2 files changed, 25 insertions(+)
+
+--- a/src/ap/drv_callbacks.c
++++ b/src/ap/drv_callbacks.c
+@@ -129,6 +129,19 @@ int hostapd_notif_assoc(struct hostapd_d
+ "hostapd_notif_assoc: Skip event with no address");
+ return -1;
+ }
++
++ if (is_multicast_ether_addr(addr) ||
++ is_zero_ether_addr(addr) ||
++ os_memcmp(addr, hapd->own_addr, ETH_ALEN) == 0) {
++ /* Do not process any frames with unexpected/invalid SA so that
++ * we do not add any state for unexpected STA addresses or end
++ * up sending out frames to unexpected destination. */
++ wpa_printf(MSG_DEBUG, "%s: Invalid SA=" MACSTR
++ " in received indication - ignore this indication silently",
++ __func__, MAC2STR(addr));
++ return 0;
++ }
++
+ random_add_randomness(addr, ETH_ALEN);
+
+ hostapd_logger(hapd, addr, HOSTAPD_MODULE_IEEE80211,
+--- a/src/ap/ieee802_11.c
++++ b/src/ap/ieee802_11.c
+@@ -3978,6 +3978,18 @@ int ieee802_11_mgmt(struct hostapd_data
+ fc = le_to_host16(mgmt->frame_control);
+ stype = WLAN_FC_GET_STYPE(fc);
+
++ if (is_multicast_ether_addr(mgmt->sa) ||
++ is_zero_ether_addr(mgmt->sa) ||
++ os_memcmp(mgmt->sa, hapd->own_addr, ETH_ALEN) == 0) {
++ /* Do not process any frames with unexpected/invalid SA so that
++ * we do not add any state for unexpected STA addresses or end
++ * up sending out frames to unexpected destination. */
++ wpa_printf(MSG_DEBUG, "MGMT: Invalid SA=" MACSTR
++ " in received frame - ignore this frame silently",
++ MAC2STR(mgmt->sa));
++ return 0;
++ }
++
+ if (stype == WLAN_FC_STYPE_BEACON) {
+ handle_beacon(hapd, mgmt, len, fi);
+ return 1;
sta = ap_get_sta(hapd, mgmt->sa);
if (sta == NULL) {
wpa_msg(hapd->msg_ctx, MSG_DEBUG, "Station " MACSTR " trying "
-@@ -4077,7 +4106,7 @@ int ieee802_11_mgmt(struct hostapd_data
+@@ -4089,7 +4118,7 @@ int ieee802_11_mgmt(struct hostapd_data
if (stype == WLAN_FC_STYPE_PROBE_REQ) {
return 1;
}
-@@ -4097,17 +4126,17 @@ int ieee802_11_mgmt(struct hostapd_data
+@@ -4109,17 +4138,17 @@ int ieee802_11_mgmt(struct hostapd_data
switch (stype) {
case WLAN_FC_STYPE_AUTH:
wpa_printf(MSG_DEBUG, "mgmt::auth");
if (addr == NULL) {
/*
-@@ -195,6 +199,12 @@ int hostapd_notif_assoc(struct hostapd_d
+@@ -208,6 +212,12 @@ int hostapd_notif_assoc(struct hostapd_d
goto fail;
}