Update default wpa_group_rekey to once-per-day when using CCMP/GCMP

The default value for GTK rekeying period was previously hardcoded to
600 seconds for all cases. Leave that short value only for TKIP as group
cipher while moving to the IEEE 802.11 default value of 86400 seconds
(once-per-day) for CCMP/GCMP.

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

hostapd/config_file.c

@@ -2513,6 +2513,7 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 		bss->wpa = atoi(pos);
 	} else if (os_strcmp(buf, "wpa_group_rekey") == 0) {
 		bss->wpa_group_rekey = atoi(pos);
+		bss->wpa_group_rekey_set = 1;
 	} else if (os_strcmp(buf, "wpa_strict_rekey") == 0) {
 		bss->wpa_strict_rekey = atoi(pos);
 	} else if (os_strcmp(buf, "wpa_gmk_rekey") == 0) {

hostapd/hostapd.conf

@@ -1282,7 +1282,10 @@ own_ip_addr=127.0.0.1
 
 # Time interval for rekeying GTK (broadcast/multicast encryption keys) in
 # seconds. (dot11RSNAConfigGroupRekeyTime)
-#wpa_group_rekey=600
+# This defaults to 86400 seconds (once per day) when using CCMP/GCMP as the
+# group cipher and 600 seconds (once per 10 minutes) when using TKIP as the
+# group cipher.
+#wpa_group_rekey=86400
 
 # Rekey GTK when any STA that possesses the current GTK is leaving the BSS.
 # (dot11RSNAConfigGroupRekeyStrict)

src/ap/ap_config.c

@@ -1036,6 +1036,9 @@ void hostapd_set_security_params(struct hostapd_bss_config *bss,
 		bss->rsn_pairwise = bss->wpa_pairwise;
 	bss->wpa_group = wpa_select_ap_group_cipher(bss->wpa, bss->wpa_pairwise,
 						    bss->rsn_pairwise);
+	if (!bss->wpa_group_rekey_set)
+		bss->wpa_group_rekey = bss->wpa_group == WPA_CIPHER_TKIP ?
+			600 : 86400;
 
 	if (full_config) {
 		bss->radius->auth_server = bss->radius->auth_servers;

src/ap/ap_config.h

@@ -327,6 +327,7 @@ struct hostapd_bss_config {
 	int wpa_pairwise;
 	int wpa_group;
 	int wpa_group_rekey;
+	int wpa_group_rekey_set;
 	int wpa_strict_rekey;
 	int wpa_gmk_rekey;
 	int wpa_ptk_rekey;