Add a AP mode event message for possible PSK/passphrase mismatch

If the AP/Authenticator receives an EAPOL-Key msg 2/4 for an association
that negotiated use of PSK and the EAPOL-Key MIC does not match, it is
likely that the station is trying to use incorrect PSK/passphrase.
Report this with "AP-STA-POSSIBLE-PSK-MISMATCH <STA addr>" control
interface event.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/ap/wpa_auth.c

@@ -67,6 +67,14 @@ static inline int wpa_auth_mic_failure_report(
 }
 
 
+static inline void wpa_auth_psk_failure_report(
+	struct wpa_authenticator *wpa_auth, const u8 *addr)
+{
+	if (wpa_auth->cb.psk_failure_report)
+		wpa_auth->cb.psk_failure_report(wpa_auth->cb.ctx, addr);
+}
+
+
 static inline void wpa_auth_set_eapol(struct wpa_authenticator *wpa_auth,
 				      const u8 *addr, wpa_eapol_variable var,
 				      int value)
@@ -1985,7 +1993,7 @@ static int wpa_derive_ptk(struct wpa_state_machine *sm, const u8 *snonce,
 SM_STATE(WPA_PTK, PTKCALCNEGOTIATING)
 {
 	struct wpa_ptk PTK;
-	int ok = 0;
+	int ok = 0, psk_found = 0;
 	const u8 *pmk = NULL;
 
 	SM_ENTRY_MA(WPA_PTK, PTKCALCNEGOTIATING, wpa_ptk);
@@ -2001,6 +2009,7 @@ SM_STATE(WPA_PTK, PTKCALCNEGOTIATING)
 					       sm->p2p_dev_addr, pmk);
 			if (pmk == NULL)
 				break;
+			psk_found = 1;
 		} else
 			pmk = sm->PMK;
 
@@ -2020,6 +2029,8 @@ SM_STATE(WPA_PTK, PTKCALCNEGOTIATING)
 	if (!ok) {
 		wpa_auth_logger(sm->wpa_auth, sm->addr, LOGGER_DEBUG,
 				"invalid MIC in msg 2/4 of 4-Way Handshake");
+		if (psk_found)
+			wpa_auth_psk_failure_report(sm->wpa_auth, sm->addr);
 		return;
 	}
 

src/ap/wpa_auth.h

@@ -189,6 +189,7 @@ struct wpa_auth_callbacks {
 		       const char *txt);
 	void (*disconnect)(void *ctx, const u8 *addr, u16 reason);
 	int (*mic_failure_report)(void *ctx, const u8 *addr);
+	void (*psk_failure_report)(void *ctx, const u8 *addr);
 	void (*set_eapol)(void *ctx, const u8 *addr, wpa_eapol_variable var,
 			  int value);
 	int (*get_eapol)(void *ctx, const u8 *addr, wpa_eapol_variable var);

src/ap/wpa_auth_glue.c

@@ -11,6 +11,7 @@
 #include "utils/common.h"
 #include "common/ieee802_11_defs.h"
 #include "common/sae.h"
+#include "common/wpa_ctrl.h"
 #include "eapol_auth/eapol_auth_sm.h"
 #include "eapol_auth/eapol_auth_sm_i.h"
 #include "eap_server/eap.h"
@@ -144,6 +145,14 @@ static int hostapd_wpa_auth_mic_failure_report(void *ctx, const u8 *addr)
 }
 
 
+static void hostapd_wpa_auth_psk_failure_report(void *ctx, const u8 *addr)
+{
+	struct hostapd_data *hapd = ctx;
+	wpa_msg(hapd->msg_ctx, MSG_INFO, AP_STA_POSSIBLE_PSK_MISMATCH MACSTR,
+		MAC2STR(addr));
+}
+
+
 static void hostapd_wpa_auth_set_eapol(void *ctx, const u8 *addr,
 				       wpa_eapol_variable var, int value)
 {
@@ -579,6 +588,7 @@ int hostapd_setup_wpa(struct hostapd_data *hapd)
 	cb.logger = hostapd_wpa_auth_logger;
 	cb.disconnect = hostapd_wpa_auth_disconnect;
 	cb.mic_failure_report = hostapd_wpa_auth_mic_failure_report;
+	cb.psk_failure_report = hostapd_wpa_auth_psk_failure_report;
 	cb.set_eapol = hostapd_wpa_auth_set_eapol;
 	cb.get_eapol = hostapd_wpa_auth_get_eapol;
 	cb.get_psk = hostapd_wpa_auth_get_psk;

src/common/wpa_ctrl.h

@@ -227,6 +227,7 @@ extern "C" {
 #define WPS_EVENT_AP_PIN_DISABLED "WPS-AP-PIN-DISABLED "
 #define AP_STA_CONNECTED "AP-STA-CONNECTED "
 #define AP_STA_DISCONNECTED "AP-STA-DISCONNECTED "
+#define AP_STA_POSSIBLE_PSK_MISMATCH "AP-STA-POSSIBLE-PSK-MISMATCH "
 
 #define AP_REJECTED_MAX_STA "AP-REJECTED-MAX-STA "
 #define AP_REJECTED_BLOCKED_STA "AP-REJECTED-BLOCKED-STA "