From 84851007d9b5e75fb7d9ae9893922e19329ecbfa Mon Sep 17 00:00:00 2001 From: Thomas Winter Date: Tue, 27 Aug 2019 15:55:37 +1200 Subject: [PATCH] mka: Check OLPN for exhaustion on SAKuse encode Most of the time is spent in the CP state machine RETIRE state where LKI is not set and OKI is the currently used SAK, so OLPN needs to be checked for PN exhaustion. hostapd/wpa_supplicant implemented an interpretation of the standard as described in a proposed amendment titled "MKA pending PN exhastion" which was deemed to be wrong. This amendment was included in IEEE Std 802.1Xck-2018. Signed-off-by: Thomas Winter --- src/pae/ieee802_1x_kay.c | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-) diff --git a/src/pae/ieee802_1x_kay.c b/src/pae/ieee802_1x_kay.c index a330d0cf4..9ec76a33b 100644 --- a/src/pae/ieee802_1x_kay.c +++ b/src/pae/ieee802_1x_kay.c @@ -1287,7 +1287,7 @@ ieee802_1x_mka_encode_sak_use_body( struct ieee802_1x_mka_sak_use_body *body; struct ieee802_1x_kay *kay = participant->kay; unsigned int length; - u32 pn = 1; + u32 olpn, llpn; length = ieee802_1x_mka_get_sak_use_length(participant); body = wpabuf_put(buf, length); @@ -1307,18 +1307,31 @@ ieee802_1x_mka_encode_sak_use_body( /* data delay protect */ body->delay_protect = kay->mka_hello_time <= MKA_BOUNDED_HELLO_TIME; - /* lowest accept packet number */ - pn = ieee802_1x_mka_get_lpn(participant, &participant->lki); - if (pn > kay->pn_exhaustion) { - wpa_printf(MSG_WARNING, "KaY: My LPN exhaustion"); - if (participant->is_key_server) - participant->new_sak = TRUE; + /* lowest accept packet numbers */ + olpn = ieee802_1x_mka_get_lpn(participant, &participant->oki); + body->olpn = host_to_be32(olpn); + llpn = ieee802_1x_mka_get_lpn(participant, &participant->lki); + body->llpn = host_to_be32(llpn); + if (participant->is_key_server) { + /* The CP will spend most of it's time in RETIRE where only + * the old key is populated. Therefore we should be checking + * the OLPN most of the time. + */ + if (participant->lrx) { + if (llpn > kay->pn_exhaustion) { + wpa_printf(MSG_WARNING, + "KaY: My LLPN exhaustion"); + participant->new_sak = TRUE; + } + } else { + if (olpn > kay->pn_exhaustion) { + wpa_printf(MSG_WARNING, + "KaY: My OLPN exhaustion"); + participant->new_sak = TRUE; + } + } } - body->llpn = host_to_be32(pn); - pn = ieee802_1x_mka_get_lpn(participant, &participant->oki); - body->olpn = host_to_be32(pn); - /* plain tx, plain rx */ body->ptx = !kay->macsec_protect; body->prx = kay->macsec_validate != Strict;