diff options
Diffstat (limited to 'package/network/services/hostapd/patches/010-Optional-AP-side-workaround-for-key-reinstallation-a.patch')
-rw-r--r-- | package/network/services/hostapd/patches/010-Optional-AP-side-workaround-for-key-reinstallation-a.patch | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/package/network/services/hostapd/patches/010-Optional-AP-side-workaround-for-key-reinstallation-a.patch b/package/network/services/hostapd/patches/010-Optional-AP-side-workaround-for-key-reinstallation-a.patch new file mode 100644 index 0000000000..19165cce2d --- /dev/null +++ b/package/network/services/hostapd/patches/010-Optional-AP-side-workaround-for-key-reinstallation-a.patch @@ -0,0 +1,221 @@ +From 6f234c1e2ee1ede29f2412b7012b3345ed8e52d3 Mon Sep 17 00:00:00 2001 +From: Jouni Malinen <j@w1.fi> +Date: Mon, 16 Oct 2017 18:37:43 +0300 +Subject: [PATCH] Optional AP side workaround for key reinstallation attacks + +This adds a new hostapd configuration parameter +wpa_disable_eapol_key_retries=1 that can be used to disable +retransmission of EAPOL-Key frames that are used to install +keys (EAPOL-Key message 3/4 and group message 1/2). This is +similar to setting wpa_group_update_count=1 and +wpa_pairwise_update_count=1, but with no impact to message 1/4 +retries and with extended timeout for messages 4/4 and group +message 2/2 to avoid causing issues with stations that may use +aggressive power saving have very long time in replying to the +EAPOL-Key messages. + +This option can be used to work around key reinstallation attacks +on the station (supplicant) side in cases those station devices +cannot be updated for some reason. By removing the +retransmissions the attacker cannot cause key reinstallation with +a delayed frame transmission. This is related to the station side +vulnerabilities CVE-2017-13077, CVE-2017-13078, CVE-2017-13079, +CVE-2017-13080, and CVE-2017-13081. + +This workaround might cause interoperability issues and reduced +robustness of key negotiation especially in environments with +heavy traffic load due to the number of attempts to perform the +key exchange is reduced significantly. As such, this workaround +is disabled by default (unless overridden in build +configuration). To enable this, set the parameter to 1. + +It is also possible to enable this in the build by default by +adding the following to the build configuration: + +CFLAGS += -DDEFAULT_WPA_DISABLE_EAPOL_KEY_RETRIES=1 + +Signed-off-by: Jouni Malinen <j@w1.fi> +--- + hostapd/config_file.c | 2 ++ + hostapd/defconfig | 4 ++++ + hostapd/hostapd.conf | 24 ++++++++++++++++++++++++ + src/ap/ap_config.c | 6 ++++++ + src/ap/ap_config.h | 1 + + src/ap/wpa_auth.c | 22 ++++++++++++++++++++-- + src/ap/wpa_auth.h | 1 + + src/ap/wpa_auth_glue.c | 2 ++ + 8 files changed, 60 insertions(+), 2 deletions(-) + +--- a/hostapd/config_file.c ++++ b/hostapd/config_file.c +@@ -2542,6 +2542,8 @@ static int hostapd_config_fill(struct ho + return 1; + } + bss->wpa_pairwise_update_count = (u32) val; ++ } else if (os_strcmp(buf, "wpa_disable_eapol_key_retries") == 0) { ++ bss->wpa_disable_eapol_key_retries = atoi(pos); + } else if (os_strcmp(buf, "wpa_passphrase") == 0) { + int len = os_strlen(pos); + if (len < 8 || len > 63) { +--- a/hostapd/defconfig ++++ b/hostapd/defconfig +@@ -372,3 +372,7 @@ CONFIG_IPV6=y + # Opportunistic Wireless Encryption (OWE) + # Experimental implementation of draft-harkins-owe-07.txt + #CONFIG_OWE=y ++ ++# Override default value for the wpa_disable_eapol_key_retries configuration ++# parameter. See that parameter in hostapd.conf for more details. ++#CFLAGS += -DDEFAULT_WPA_DISABLE_EAPOL_KEY_RETRIES=1 +--- a/hostapd/hostapd.conf ++++ b/hostapd/hostapd.conf +@@ -1315,6 +1315,30 @@ own_ip_addr=127.0.0.1 + # Range 1..4294967295; default: 4 + #wpa_pairwise_update_count=4 + ++# Workaround for key reinstallation attacks ++# ++# This parameter can be used to disable retransmission of EAPOL-Key frames that ++# are used to install keys (EAPOL-Key message 3/4 and group message 1/2). This ++# is similar to setting wpa_group_update_count=1 and ++# wpa_pairwise_update_count=1, but with no impact to message 1/4 and with ++# extended timeout on the response to avoid causing issues with stations that ++# may use aggressive power saving have very long time in replying to the ++# EAPOL-Key messages. ++# ++# This option can be used to work around key reinstallation attacks on the ++# station (supplicant) side in cases those station devices cannot be updated ++# for some reason. By removing the retransmissions the attacker cannot cause ++# key reinstallation with a delayed frame transmission. This is related to the ++# station side vulnerabilities CVE-2017-13077, CVE-2017-13078, CVE-2017-13079, ++# CVE-2017-13080, and CVE-2017-13081. ++# ++# This workaround might cause interoperability issues and reduced robustness of ++# key negotiation especially in environments with heavy traffic load due to the ++# number of attempts to perform the key exchange is reduced significantly. As ++# such, this workaround is disabled by default (unless overridden in build ++# configuration). To enable this, set the parameter to 1. ++#wpa_disable_eapol_key_retries=1 ++ + # 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. +--- a/src/ap/ap_config.c ++++ b/src/ap/ap_config.c +@@ -37,6 +37,10 @@ static void hostapd_config_free_vlan(str + } + + ++#ifndef DEFAULT_WPA_DISABLE_EAPOL_KEY_RETRIES ++#define DEFAULT_WPA_DISABLE_EAPOL_KEY_RETRIES 0 ++#endif /* DEFAULT_WPA_DISABLE_EAPOL_KEY_RETRIES */ ++ + void hostapd_config_defaults_bss(struct hostapd_bss_config *bss) + { + dl_list_init(&bss->anqp_elem); +@@ -58,6 +62,8 @@ void hostapd_config_defaults_bss(struct + bss->wpa_gmk_rekey = 86400; + bss->wpa_group_update_count = 4; + bss->wpa_pairwise_update_count = 4; ++ bss->wpa_disable_eapol_key_retries = ++ DEFAULT_WPA_DISABLE_EAPOL_KEY_RETRIES; + bss->wpa_key_mgmt = WPA_KEY_MGMT_PSK; + bss->wpa_pairwise = WPA_CIPHER_TKIP; + bss->wpa_group = WPA_CIPHER_TKIP; +--- a/src/ap/ap_config.h ++++ b/src/ap/ap_config.h +@@ -333,6 +333,7 @@ struct hostapd_bss_config { + int wpa_ptk_rekey; + u32 wpa_group_update_count; + u32 wpa_pairwise_update_count; ++ int wpa_disable_eapol_key_retries; + int rsn_pairwise; + int rsn_preauth; + char *rsn_preauth_interfaces; +--- a/src/ap/wpa_auth.c ++++ b/src/ap/wpa_auth.c +@@ -65,6 +65,7 @@ static u8 * ieee80211w_kde_add(struct wp + 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 */ ++static const u32 eapol_key_timeout_no_retrans = 4000; /* ms */ + + /* TODO: make these configurable */ + static const int dot11RSNAConfigPMKLifetime = 43200; +@@ -1653,6 +1654,9 @@ static void wpa_send_eapol(struct wpa_au + eapol_key_timeout_first_group; + else + timeout_ms = eapol_key_timeout_subseq; ++ if (wpa_auth->conf.wpa_disable_eapol_key_retries && ++ (!pairwise || (key_info & WPA_KEY_INFO_MIC))) ++ timeout_ms = eapol_key_timeout_no_retrans; + 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 " +@@ -2882,6 +2886,11 @@ SM_STATE(WPA_PTK, PTKINITNEGOTIATING) + sm->TimeoutEvt = FALSE; + + sm->TimeoutCtr++; ++ if (sm->wpa_auth->conf.wpa_disable_eapol_key_retries && ++ sm->TimeoutCtr > 1) { ++ /* Do not allow retransmission of EAPOL-Key msg 3/4 */ ++ return; ++ } + if (sm->TimeoutCtr > sm->wpa_auth->conf.wpa_pairwise_update_count) { + /* No point in sending the EAPOL-Key - we will disconnect + * immediately following this. */ +@@ -3220,7 +3229,9 @@ SM_STEP(WPA_PTK) + sm->EAPOLKeyPairwise && sm->MICVerified) + SM_ENTER(WPA_PTK, PTKINITDONE); + else if (sm->TimeoutCtr > +- sm->wpa_auth->conf.wpa_pairwise_update_count) { ++ sm->wpa_auth->conf.wpa_pairwise_update_count || ++ (sm->wpa_auth->conf.wpa_disable_eapol_key_retries && ++ sm->TimeoutCtr > 1)) { + wpa_auth->dot11RSNA4WayHandshakeFailures++; + wpa_auth_vlogger( + sm->wpa_auth, sm->addr, LOGGER_DEBUG, +@@ -3260,6 +3271,11 @@ SM_STATE(WPA_PTK_GROUP, REKEYNEGOTIATING + SM_ENTRY_MA(WPA_PTK_GROUP, REKEYNEGOTIATING, wpa_ptk_group); + + sm->GTimeoutCtr++; ++ if (sm->wpa_auth->conf.wpa_disable_eapol_key_retries && ++ sm->GTimeoutCtr > 1) { ++ /* Do not allow retransmission of EAPOL-Key group msg 1/2 */ ++ return; ++ } + if (sm->GTimeoutCtr > sm->wpa_auth->conf.wpa_group_update_count) { + /* No point in sending the EAPOL-Key - we will disconnect + * immediately following this. */ +@@ -3363,7 +3379,9 @@ SM_STEP(WPA_PTK_GROUP) + !sm->EAPOLKeyPairwise && sm->MICVerified) + SM_ENTER(WPA_PTK_GROUP, REKEYESTABLISHED); + else if (sm->GTimeoutCtr > +- sm->wpa_auth->conf.wpa_group_update_count) ++ sm->wpa_auth->conf.wpa_group_update_count || ++ (sm->wpa_auth->conf.wpa_disable_eapol_key_retries && ++ sm->GTimeoutCtr > 1)) + SM_ENTER(WPA_PTK_GROUP, KEYERROR); + else if (sm->TimeoutEvt) + SM_ENTER(WPA_PTK_GROUP, REKEYNEGOTIATING); +--- a/src/ap/wpa_auth.h ++++ b/src/ap/wpa_auth.h +@@ -165,6 +165,7 @@ struct wpa_auth_config { + int wpa_ptk_rekey; + u32 wpa_group_update_count; + u32 wpa_pairwise_update_count; ++ int wpa_disable_eapol_key_retries; + int rsn_pairwise; + int rsn_preauth; + int eapol_version; +--- a/src/ap/wpa_auth_glue.c ++++ b/src/ap/wpa_auth_glue.c +@@ -45,6 +45,8 @@ static void hostapd_wpa_auth_conf(struct + 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_disable_eapol_key_retries = ++ conf->wpa_disable_eapol_key_retries; + wconf->wpa_pairwise_update_count = conf->wpa_pairwise_update_count; + wconf->rsn_pairwise = conf->rsn_pairwise; + wconf->rsn_preauth = conf->rsn_preauth; |