From 41f140d38617e1fd3fa88c1667c1bce0cad79224 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=BCnther=20Kelleter?= <guenther.kelleter@devolo.de>
Date: Thu, 5 Jan 2017 17:00:33 +0100
Subject: [PATCH] Add hostapd options wpa_group_update_count and
 wpa_pairwise_update_count
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

wpa_group_update_count and wpa_pairwise_update_count can now be used to
set the GTK and PTK rekey retry limits (dot11RSNAConfigGroupUpdateCount
and dot11RSNAConfigPairwiseUpdateCount). Defaults set to current
hardcoded value (4).

Some stations may suffer from frequent deauthentications due to GTK
rekey failures: EAPOL 1/2 frame is not answered during the total timeout
period of currently ~3.5 seconds. For example, a Galaxy S6 with Android
6.0.1 appears to go into power save mode for up to 5 seconds. Increasing
wpa_group_update_count to 6 fixed this issue.

Signed-off-by: Günther Kelleter <guenther.kelleter@devolo.de>
---
 hostapd/config_file.c     | 22 ++++++++++++++++++++++
 hostapd/hostapd.conf      | 11 +++++++++++
 src/ap/ap_config.c        |  2 ++
 src/ap/ap_config.h        |  2 ++
 src/ap/wpa_auth.c         | 37 ++++++++++++++++++-------------------
 src/ap/wpa_auth.h         |  2 ++
 src/ap/wpa_auth_glue.c    |  2 ++
 src/ap/wpa_auth_i.h       |  4 ++--
 wpa_supplicant/ibss_rsn.c |  2 ++
 wpa_supplicant/mesh_rsn.c |  2 ++
 10 files changed, 65 insertions(+), 21 deletions(-)

diff --git a/hostapd/config_file.c b/hostapd/config_file.c
index 8cfa198c3..02693a5b1 100644
--- a/hostapd/config_file.c
+++ b/hostapd/config_file.c
@@ -2489,6 +2489,28 @@ static int hostapd_config_fill(struct hostapd_config *conf,
 		bss->wpa_gmk_rekey = atoi(pos);
 	} else if (os_strcmp(buf, "wpa_ptk_rekey") == 0) {
 		bss->wpa_ptk_rekey = atoi(pos);
+	} else if (os_strcmp(buf, "wpa_group_update_count") == 0) {
+		char *endp;
+		unsigned long val = strtoul(pos, &endp, 0);
+
+		if (*endp || val < 1 || val > (u32) -1) {
+			wpa_printf(MSG_ERROR,
+				   "Line %d: Invalid wpa_group_update_count=%lu; allowed range 1..4294967295",
+				   line, val);
+			return 1;
+		}
+		bss->wpa_group_update_count = (u32) val;
+	} else if (os_strcmp(buf, "wpa_pairwise_update_count") == 0) {
+		char *endp;
+		unsigned long val = strtoul(pos, &endp, 0);
+
+		if (*endp || val < 1 || val > (u32) -1) {
+			wpa_printf(MSG_ERROR,
+				   "Line %d: Invalid wpa_pairwise_update_count=%lu; allowed range 1..4294967295",
+				   line, val);
+			return 1;
+		}
+		bss->wpa_pairwise_update_count = (u32) val;
 	} else if (os_strcmp(buf, "wpa_passphrase") == 0) {
 		int len = os_strlen(pos);
 		if (len < 8 || len > 63) {
diff --git a/hostapd/hostapd.conf b/hostapd/hostapd.conf
index 314f3842b..1fb1bd987 100644
--- a/hostapd/hostapd.conf
+++ b/hostapd/hostapd.conf
@@ -1221,6 +1221,11 @@ own_ip_addr=127.0.0.1
 # (dot11RSNAConfigGroupRekeyStrict)
 #wpa_strict_rekey=1
 
+# The number of times EAPOL-Key Message 1/2 in the RSN Group Key Handshake is
+#retried per GTK Handshake attempt. (dot11RSNAConfigGroupUpdateCount)
+# Range 1..4294967295; default: 4
+#wpa_group_update_count=4
+
 # Time interval for rekeying GMK (master key used internally to generate GTKs
 # (in seconds).
 #wpa_gmk_rekey=86400
@@ -1229,6 +1234,12 @@ own_ip_addr=127.0.0.1
 # PTK to mitigate some attacks against TKIP deficiencies.
 #wpa_ptk_rekey=600
 
+# The number of times EAPOL-Key Message 1/4 and Message 3/4 in the RSN 4-Way
+# Handshake are retried per 4-Way Handshake attempt.
+# (dot11RSNAConfigPairwiseUpdateCount)
+# Range 1..4294967295; default: 4
+#wpa_pairwise_update_count=4
+
 # Enable IEEE 802.11i/RSN/WPA2 pre-authentication. This is used to speed up
 # roaming be pre-authenticating IEEE 802.1X/EAP part of the full RSN
 # authentication and key handshake before actually associating with a new AP.
diff --git a/src/ap/ap_config.c b/src/ap/ap_config.c
index c2b80ad97..9abcab7fb 100644
--- a/src/ap/ap_config.c
+++ b/src/ap/ap_config.c
@@ -56,6 +56,8 @@ void hostapd_config_defaults_bss(struct hostapd_bss_config *bss)
 
 	bss->wpa_group_rekey = 600;
 	bss->wpa_gmk_rekey = 86400;
+	bss->wpa_group_update_count = 4;
+	bss->wpa_pairwise_update_count = 4;
 	bss->wpa_key_mgmt = WPA_KEY_MGMT_PSK;
 	bss->wpa_pairwise = WPA_CIPHER_TKIP;
 	bss->wpa_group = WPA_CIPHER_TKIP;
diff --git a/src/ap/ap_config.h b/src/ap/ap_config.h
index 31b1e7762..7495dc96f 100644
--- a/src/ap/ap_config.h
+++ b/src/ap/ap_config.h
@@ -330,6 +330,8 @@ struct hostapd_bss_config {
 	int wpa_strict_rekey;
 	int wpa_gmk_rekey;
 	int wpa_ptk_rekey;
+	u32 wpa_group_update_count;
+	u32 wpa_pairwise_update_count;
 	int rsn_pairwise;
 	int rsn_preauth;
 	char *rsn_preauth_interfaces;
diff --git a/src/ap/wpa_auth.c b/src/ap/wpa_auth.c
index 0bd901fbf..8c082f426 100644
--- a/src/ap/wpa_auth.c
+++ b/src/ap/wpa_auth.c
@@ -60,8 +60,6 @@ static void wpa_group_put(struct wpa_authenticator *wpa_auth,
 			  struct wpa_group *group);
 static u8 * ieee80211w_kde_add(struct wpa_state_machine *sm, u8 *pos);
 
-static const u32 dot11RSNAConfigGroupUpdateCount = 4;
-static const u32 dot11RSNAConfigPairwiseUpdateCount = 4;
 static const u32 eapol_key_timeout_first = 100; /* ms */
 static const u32 eapol_key_timeout_subseq = 1000; /* ms */
 static const u32 eapol_key_timeout_first_group = 500; /* ms */
@@ -1623,7 +1621,7 @@ static void wpa_send_eapol(struct wpa_authenticator *wpa_auth,
 {
 	int timeout_ms;
 	int pairwise = key_info & WPA_KEY_INFO_KEY_TYPE;
-	int ctr;
+	u32 ctr;
 
 	if (sm == NULL)
 		return;
@@ -1640,7 +1638,7 @@ static void wpa_send_eapol(struct wpa_authenticator *wpa_auth,
 	if (pairwise && ctr == 1 && !(key_info & WPA_KEY_INFO_MIC))
 		sm->pending_1_of_4_timeout = 1;
 	wpa_printf(MSG_DEBUG, "WPA: Use EAPOL-Key timeout of %u ms (retry "
-		   "counter %d)", timeout_ms, ctr);
+		   "counter %u)", timeout_ms, ctr);
 	eloop_register_timeout(timeout_ms / 1000, (timeout_ms % 1000) * 1000,
 			       wpa_send_eapol_timeout, wpa_auth, sm);
 }
@@ -2002,7 +2000,7 @@ SM_STATE(WPA_PTK, PTKSTART)
 	sm->alt_snonce_valid = FALSE;
 
 	sm->TimeoutCtr++;
-	if (sm->TimeoutCtr > (int) dot11RSNAConfigPairwiseUpdateCount) {
+	if (sm->TimeoutCtr > sm->wpa_auth->conf.wpa_pairwise_update_count) {
 		/* No point in sending the EAPOL-Key - we will disconnect
 		 * immediately following this. */
 		return;
@@ -2693,7 +2691,7 @@ SM_STATE(WPA_PTK, PTKINITNEGOTIATING)
 	sm->TimeoutEvt = FALSE;
 
 	sm->TimeoutCtr++;
-	if (sm->TimeoutCtr > (int) dot11RSNAConfigPairwiseUpdateCount) {
+	if (sm->TimeoutCtr > sm->wpa_auth->conf.wpa_pairwise_update_count) {
 		/* No point in sending the EAPOL-Key - we will disconnect
 		 * immediately following this. */
 		return;
@@ -2988,11 +2986,12 @@ SM_STEP(WPA_PTK)
 		    sm->EAPOLKeyPairwise)
 			SM_ENTER(WPA_PTK, PTKCALCNEGOTIATING);
 		else if (sm->TimeoutCtr >
-			 (int) dot11RSNAConfigPairwiseUpdateCount) {
+			 sm->wpa_auth->conf.wpa_pairwise_update_count) {
 			wpa_auth->dot11RSNA4WayHandshakeFailures++;
-			wpa_auth_vlogger(sm->wpa_auth, sm->addr, LOGGER_DEBUG,
-					 "PTKSTART: Retry limit %d reached",
-					 dot11RSNAConfigPairwiseUpdateCount);
+			wpa_auth_vlogger(
+				sm->wpa_auth, sm->addr, LOGGER_DEBUG,
+				"PTKSTART: Retry limit %u reached",
+				sm->wpa_auth->conf.wpa_pairwise_update_count);
 			SM_ENTER(WPA_PTK, DISCONNECT);
 		} else if (sm->TimeoutEvt)
 			SM_ENTER(WPA_PTK, PTKSTART);
@@ -3016,12 +3015,12 @@ SM_STEP(WPA_PTK)
 			 sm->EAPOLKeyPairwise && sm->MICVerified)
 			SM_ENTER(WPA_PTK, PTKINITDONE);
 		else if (sm->TimeoutCtr >
-			 (int) dot11RSNAConfigPairwiseUpdateCount) {
+			 sm->wpa_auth->conf.wpa_pairwise_update_count) {
 			wpa_auth->dot11RSNA4WayHandshakeFailures++;
-			wpa_auth_vlogger(sm->wpa_auth, sm->addr, LOGGER_DEBUG,
-					 "PTKINITNEGOTIATING: Retry limit %d "
-					 "reached",
-					 dot11RSNAConfigPairwiseUpdateCount);
+			wpa_auth_vlogger(
+				sm->wpa_auth, sm->addr, LOGGER_DEBUG,
+				"PTKINITNEGOTIATING: Retry limit %u reached",
+				sm->wpa_auth->conf.wpa_pairwise_update_count);
 			SM_ENTER(WPA_PTK, DISCONNECT);
 		} else if (sm->TimeoutEvt)
 			SM_ENTER(WPA_PTK, PTKINITNEGOTIATING);
@@ -3056,7 +3055,7 @@ SM_STATE(WPA_PTK_GROUP, REKEYNEGOTIATING)
 	SM_ENTRY_MA(WPA_PTK_GROUP, REKEYNEGOTIATING, wpa_ptk_group);
 
 	sm->GTimeoutCtr++;
-	if (sm->GTimeoutCtr > (int) dot11RSNAConfigGroupUpdateCount) {
+	if (sm->GTimeoutCtr > sm->wpa_auth->conf.wpa_group_update_count) {
 		/* No point in sending the EAPOL-Key - we will disconnect
 		 * immediately following this. */
 		return;
@@ -3154,7 +3153,7 @@ SM_STEP(WPA_PTK_GROUP)
 		    !sm->EAPOLKeyPairwise && sm->MICVerified)
 			SM_ENTER(WPA_PTK_GROUP, REKEYESTABLISHED);
 		else if (sm->GTimeoutCtr >
-			 (int) dot11RSNAConfigGroupUpdateCount)
+			 sm->wpa_auth->conf.wpa_group_update_count)
 			SM_ENTER(WPA_PTK_GROUP, KEYERROR);
 		else if (sm->TimeoutEvt)
 			SM_ENTER(WPA_PTK_GROUP, REKEYNEGOTIATING);
@@ -3614,8 +3613,8 @@ int wpa_get_mib(struct wpa_authenticator *wpa_auth, char *buf, size_t buflen)
 		"dot11RSNAConfigNumberOfGTKSAReplayCounters=0\n",
 		RSN_VERSION,
 		!!wpa_auth->conf.wpa_strict_rekey,
-		dot11RSNAConfigGroupUpdateCount,
-		dot11RSNAConfigPairwiseUpdateCount,
+		wpa_auth->conf.wpa_group_update_count,
+		wpa_auth->conf.wpa_pairwise_update_count,
 		wpa_cipher_key_len(wpa_auth->conf.wpa_group) * 8,
 		dot11RSNAConfigPMKLifetime,
 		dot11RSNAConfigPMKReauthThreshold,
diff --git a/src/ap/wpa_auth.h b/src/ap/wpa_auth.h
index 9cbe3889b..0920a169d 100644
--- a/src/ap/wpa_auth.h
+++ b/src/ap/wpa_auth.h
@@ -144,6 +144,8 @@ struct wpa_auth_config {
 	int wpa_strict_rekey;
 	int wpa_gmk_rekey;
 	int wpa_ptk_rekey;
+	u32 wpa_group_update_count;
+	u32 wpa_pairwise_update_count;
 	int rsn_pairwise;
 	int rsn_preauth;
 	int eapol_version;
diff --git a/src/ap/wpa_auth_glue.c b/src/ap/wpa_auth_glue.c
index 22518a1f1..394f77a66 100644
--- a/src/ap/wpa_auth_glue.c
+++ b/src/ap/wpa_auth_glue.c
@@ -41,6 +41,8 @@ static void hostapd_wpa_auth_conf(struct hostapd_bss_config *conf,
 	wconf->wpa_strict_rekey = conf->wpa_strict_rekey;
 	wconf->wpa_gmk_rekey = conf->wpa_gmk_rekey;
 	wconf->wpa_ptk_rekey = conf->wpa_ptk_rekey;
+	wconf->wpa_group_update_count = conf->wpa_group_update_count;
+	wconf->wpa_pairwise_update_count = conf->wpa_pairwise_update_count;
 	wconf->rsn_pairwise = conf->rsn_pairwise;
 	wconf->rsn_preauth = conf->rsn_preauth;
 	wconf->eapol_version = conf->eapol_version;
diff --git a/src/ap/wpa_auth_i.h b/src/ap/wpa_auth_i.h
index 065a624ad..cda2c5065 100644
--- a/src/ap/wpa_auth_i.h
+++ b/src/ap/wpa_auth_i.h
@@ -48,8 +48,8 @@ struct wpa_state_machine {
 	Boolean AuthenticationRequest;
 	Boolean ReAuthenticationRequest;
 	Boolean Disconnect;
-	int TimeoutCtr;
-	int GTimeoutCtr;
+	u32 TimeoutCtr;
+	u32 GTimeoutCtr;
 	Boolean TimeoutEvt;
 	Boolean EAPOLKeyReceived;
 	Boolean EAPOLKeyPairwise;
diff --git a/wpa_supplicant/ibss_rsn.c b/wpa_supplicant/ibss_rsn.c
index 521a692ba..954061ae4 100644
--- a/wpa_supplicant/ibss_rsn.c
+++ b/wpa_supplicant/ibss_rsn.c
@@ -428,6 +428,8 @@ static int ibss_rsn_auth_init_group(struct ibss_rsn *ibss_rsn,
 	conf.wpa_group = WPA_CIPHER_CCMP;
 	conf.eapol_version = 2;
 	conf.wpa_group_rekey = ssid->group_rekey ? ssid->group_rekey : 600;
+	conf.wpa_group_update_count = 4;
+	conf.wpa_pairwise_update_count = 4;
 
 	ibss_rsn->auth_group = wpa_init(own_addr, &conf, &cb, ibss_rsn);
 	if (ibss_rsn->auth_group == NULL) {
diff --git a/wpa_supplicant/mesh_rsn.c b/wpa_supplicant/mesh_rsn.c
index 33040f30b..628382cbf 100644
--- a/wpa_supplicant/mesh_rsn.c
+++ b/wpa_supplicant/mesh_rsn.c
@@ -158,6 +158,8 @@ static int __mesh_rsn_auth_init(struct mesh_rsn *rsn, const u8 *addr,
 	conf.wpa_group = rsn->group_cipher;
 	conf.eapol_version = 0;
 	conf.wpa_group_rekey = -1;
+	conf.wpa_group_update_count = 4;
+	conf.wpa_pairwise_update_count = 4;
 #ifdef CONFIG_IEEE80211W
 	conf.ieee80211w = ieee80211w;
 	if (ieee80211w != NO_MGMT_FRAME_PROTECTION)
-- 
2.13.6

