Add test code for fetching the last configured GTK

This can be useful for some test cases, so allow wpa_supplicant to be
built with special test functionality to expose the current (last
configured) GTK. This is disabled by default and can be enabled by
adding following line into .config:
CFLAGS += -DCONFIG_TESTING_GET_GTK

The GTK can then be fetched with "wpa_cli get gtk".

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

wpa_supplicant/ctrl_iface.c

@@ -461,6 +461,14 @@ static int wpa_supplicant_ctrl_iface_get(struct wpa_supplicant *wpa_s,
 			return -1;
 		return res;
 #endif /* CONFIG_WIFI_DISPLAY */
+#ifdef CONFIG_TESTING_GET_GTK
+	} else if (os_strcmp(cmd, "gtk") == 0) {
+		if (wpa_s->last_gtk_len == 0)
+			return -1;
+		res = wpa_snprintf_hex(buf, buflen, wpa_s->last_gtk,
+				       wpa_s->last_gtk_len);
+		return res;
+#endif /* CONFIG_TESTING_GET_GTK */
 	}
 
 	if (res < 0 || (unsigned int) res >= buflen)

wpa_supplicant/wpa_supplicant_i.h

@@ -708,6 +708,11 @@ struct wpa_supplicant {
 	u8 wnm_bss_termination_duration[12];
 	struct neighbor_report *wnm_neighbor_report_elements;
 #endif /* CONFIG_WNM */
+
+#ifdef CONFIG_TESTING_GET_GTK
+	u8 last_gtk[32];
+	size_t last_gtk_len;
+#endif /* CONFIG_TESTING_GET_GTK */
 };
 
 

wpa_supplicant/wpas_glue.c

@@ -437,6 +437,13 @@ static int wpa_supplicant_set_key(void *_wpa_s, enum wpa_alg alg,
 		/* Clear the MIC error counter when setting a new PTK. */
 		wpa_s->mic_errors_seen = 0;
 	}
+#ifdef CONFIG_TESTING_GET_GTK
+	if (key_idx > 0 && addr && is_broadcast_ether_addr(addr) &&
+	    alg != WPA_ALG_NONE && key_len <= sizeof(wpa_s->last_gtk)) {
+		os_memcpy(wpa_s->last_gtk, key, key_len);
+		wpa_s->last_gtk_len = key_len;
+	}
+#endif /* CONFIG_TESTING_GET_GTK */
 	return wpa_drv_set_key(wpa_s, alg, addr, key_idx, set_tx, seq, seq_len,
 			       key, key_len);
 }