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mka: Consider missing MKPDU parameter sets a failure

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The previous commit introduced parameter set error checking. This commit
extends upon that by considering missing parameter sets a failure.

Two checks are added by this commit. First, verify that live peers start
encoding MKA_SAK_USE within a reasonable amount of time after going live
(10 MKPDUs). Second, verify that once a live peer starts encoding
MKA_SAK_USE it continues to do so indefinitely.

Signed-off-by: Michael Siedzik <msiedzik@extremenetworks.com>
This commit is contained in:
Mike Siedzik 2018-02-20 14:28:44 -05:00 committed by Jouni Malinen
parent db9ca18bbf
commit e4ae284bba
2 changed files with 37 additions and 2 deletions
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38
src/pae/ieee802_1x_kay.c
View File

@ -27,6 +27,9 @@
#define DEFAULT_ICV_LEN 16
#define MAX_ICV_LEN 32 /* 32 bytes, 256 bits */
#define MAX_MISSING_SAK_USE 10 /* Accept up to 10 inbound MKPDUs without
* SAK-USE before dropping */
#define PENDING_PN_EXHAUSTION 0xC0000000
#define MKA_ALIGN_LENGTH(len) (((len) + 0x3) & ~0x3)
@ -571,6 +574,7 @@ ieee802_1x_kay_create_peer(const u8 *mi, u32 mn)
peer->mn = mn;
peer->expire = time(NULL) + MKA_LIFE_TIME / 1000;
peer->sak_used = FALSE;
peer->missing_sak_use_count = 0;
return peer;
}
@ -3146,10 +3150,40 @@ static int ieee802_1x_kay_decode_mkpdu(struct ieee802_1x_kay *kay,
return -1;
}
/* Detect missing parameter sets */
peer = ieee802_1x_kay_get_live_peer(participant,
participant->current_peer_id.mi);
if (peer) {
/* MKPDU is from live peer */
if (!handled[MKA_SAK_USE]) {
/* Once a live peer starts sending SAK-USE, it should be
* sent every time. */
if (peer->sak_used) {
wpa_printf(MSG_INFO,
"KaY: Discarding Rx MKPDU: Live Peer stopped sending SAK-USE");
return -1;
}
/* Live peer is probably hung if it hasn't sent SAK-USE
* after a reasonable number of MKPDUs. Drop the MKPDU,
* which will eventually force an timeout. */
if (++peer->missing_sak_use_count >
MAX_MISSING_SAK_USE) {
wpa_printf(MSG_INFO,
"KaY: Discarding Rx MKPDU: Live Peer not sending SAK-USE");
return -1;
}
} else {
peer->missing_sak_use_count = 0;
}
} else {
/* MKPDU is from new or potential peer */
peer = ieee802_1x_kay_get_peer(participant,
participant->current_peer_id.mi);
}
/* Only update live peer watchdog after successful decode of all
* parameter sets */
peer = ieee802_1x_kay_get_peer(participant,
participant->current_peer_id.mi);
if (peer)
peer->expire = time(NULL) + MKA_LIFE_TIME / 1000;

1
src/pae/ieee802_1x_kay_i.h
View File

@ -51,6 +51,7 @@ struct ieee802_1x_kay_peer {
Boolean macsec_desired;
enum macsec_cap macsec_capability;
Boolean sak_used;
int missing_sak_use_count;
struct dl_list list;
};