OpenBSD-4.6/sys/net80211/ieee80211_pae_input.c
/* $OpenBSD: ieee80211_pae_input.c,v 1.15 2009/01/26 19:09:41 damien Exp $ */
/*-
* Copyright (c) 2007,2008 Damien Bergamini <damien.bergamini@free.fr>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This code implements the 4-Way Handshake and Group Key Handshake protocols
* (both Supplicant and Authenticator Key Receive state machines) defined in
* IEEE Std 802.11-2007 section 8.5.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <net/if_arp.h>
#ifdef INET
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/in_systm.h>
#endif
#include <net80211/ieee80211_var.h>
#include <net80211/ieee80211_priv.h>
#include <dev/rndvar.h>
void ieee80211_recv_4way_msg1(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *);
#ifndef IEEE80211_STA_ONLY
void ieee80211_recv_4way_msg2(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *,
const u_int8_t *);
#endif
void ieee80211_recv_4way_msg3(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *);
#ifndef IEEE80211_STA_ONLY
void ieee80211_recv_4way_msg4(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *);
void ieee80211_recv_4way_msg2or4(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *);
#endif
void ieee80211_recv_rsn_group_msg1(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *);
void ieee80211_recv_wpa_group_msg1(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *);
#ifndef IEEE80211_STA_ONLY
void ieee80211_recv_group_msg2(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *);
void ieee80211_recv_eapol_key_req(struct ieee80211com *,
struct ieee80211_eapol_key *, struct ieee80211_node *);
#endif
/*
* Process an incoming EAPOL frame. Notice that we are only interested in
* EAPOL-Key frames with an IEEE 802.11 or WPA descriptor type.
*/
void
ieee80211_eapol_key_input(struct ieee80211com *ic, struct mbuf *m,
struct ieee80211_node *ni)
{
struct ifnet *ifp = &ic->ic_if;
struct ether_header *eh;
struct ieee80211_eapol_key *key;
u_int16_t info, desc;
int totlen;
ifp->if_ibytes += m->m_pkthdr.len;
eh = mtod(m, struct ether_header *);
if (IEEE80211_IS_MULTICAST(eh->ether_dhost)) {
ifp->if_imcasts++;
goto done;
}
m_adj(m, sizeof(*eh));
if (m->m_pkthdr.len < sizeof(*key))
goto done;
if (m->m_len < sizeof(*key) &&
(m = m_pullup(m, sizeof(*key))) == NULL) {
ic->ic_stats.is_rx_nombuf++;
goto done;
}
key = mtod(m, struct ieee80211_eapol_key *);
if (key->type != EAPOL_KEY)
goto done;
ic->ic_stats.is_rx_eapol_key++;
if ((ni->ni_rsnprotos == IEEE80211_PROTO_RSN &&
key->desc != EAPOL_KEY_DESC_IEEE80211) ||
(ni->ni_rsnprotos == IEEE80211_PROTO_WPA &&
key->desc != EAPOL_KEY_DESC_WPA))
goto done;
/* check packet body length */
if (m->m_pkthdr.len < 4 + BE_READ_2(key->len))
goto done;
/* check key data length */
totlen = sizeof(*key) + BE_READ_2(key->paylen);
if (m->m_pkthdr.len < totlen || totlen > MCLBYTES)
goto done;
info = BE_READ_2(key->info);
/* discard EAPOL-Key frames with an unknown descriptor version */
desc = info & EAPOL_KEY_VERSION_MASK;
if (desc < EAPOL_KEY_DESC_V1 || desc > EAPOL_KEY_DESC_V3)
goto done;
if (ieee80211_is_sha256_akm(ni->ni_rsnakms)) {
if (desc != EAPOL_KEY_DESC_V3)
goto done;
} else if (ni->ni_rsncipher == IEEE80211_CIPHER_CCMP ||
ni->ni_rsngroupcipher == IEEE80211_CIPHER_CCMP) {
if (desc != EAPOL_KEY_DESC_V2)
goto done;
}
/* make sure the key data field is contiguous */
if (m->m_len < totlen && (m = m_pullup2(m, totlen)) == NULL) {
ic->ic_stats.is_rx_nombuf++;
goto done;
}
key = mtod(m, struct ieee80211_eapol_key *);
/* determine message type (see 8.5.3.7) */
if (info & EAPOL_KEY_REQUEST) {
#ifndef IEEE80211_STA_ONLY
/* EAPOL-Key Request frame */
ieee80211_recv_eapol_key_req(ic, key, ni);
#endif
} else if (info & EAPOL_KEY_PAIRWISE) {
/* 4-Way Handshake */
if (info & EAPOL_KEY_KEYMIC) {
if (info & EAPOL_KEY_KEYACK)
ieee80211_recv_4way_msg3(ic, key, ni);
#ifndef IEEE80211_STA_ONLY
else
ieee80211_recv_4way_msg2or4(ic, key, ni);
#endif
} else if (info & EAPOL_KEY_KEYACK)
ieee80211_recv_4way_msg1(ic, key, ni);
} else {
/* Group Key Handshake */
if (!(info & EAPOL_KEY_KEYMIC))
goto done;
if (info & EAPOL_KEY_KEYACK) {
if (key->desc == EAPOL_KEY_DESC_WPA)
ieee80211_recv_wpa_group_msg1(ic, key, ni);
else
ieee80211_recv_rsn_group_msg1(ic, key, ni);
}
#ifndef IEEE80211_STA_ONLY
else
ieee80211_recv_group_msg2(ic, key, ni);
#endif
}
done:
if (m != NULL)
m_freem(m);
}
/*
* Process Message 1 of the 4-Way Handshake (sent by Authenticator).
*/
void
ieee80211_recv_4way_msg1(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
{
struct ieee80211_ptk tptk;
struct ieee80211_pmk *pmk;
const u_int8_t *frm, *efrm;
const u_int8_t *pmkid;
#ifndef IEEE80211_STA_ONLY
if (ic->ic_opmode != IEEE80211_M_STA &&
ic->ic_opmode != IEEE80211_M_IBSS)
return;
#endif
if (ni->ni_replaycnt_ok &&
BE_READ_8(key->replaycnt) <= ni->ni_replaycnt) {
ic->ic_stats.is_rx_eapol_replay++;
return;
}
/* parse key data field (may contain an encapsulated PMKID) */
frm = (const u_int8_t *)&key[1];
efrm = frm + BE_READ_2(key->paylen);
pmkid = NULL;
while (frm + 2 <= efrm) {
if (frm + 2 + frm[1] > efrm)
break;
switch (frm[0]) {
case IEEE80211_ELEMID_VENDOR:
if (frm[1] < 4)
break;
if (memcmp(&frm[2], IEEE80211_OUI, 3) == 0) {
switch (frm[5]) {
case IEEE80211_KDE_PMKID:
pmkid = frm;
break;
}
}
break;
}
frm += 2 + frm[1];
}
/* check that the PMKID KDE is valid (if present) */
if (pmkid != NULL && pmkid[1] != 4 + 16)
return;
if (ieee80211_is_8021x_akm(ni->ni_rsnakms)) {
/* retrieve the PMK for this (AP,PMKID) */
pmk = ieee80211_pmksa_find(ic, ni,
(pmkid != NULL) ? &pmkid[6] : NULL);
if (pmk == NULL) {
DPRINTF(("no PMK available for %s\n",
ether_sprintf(ni->ni_macaddr)));
return;
}
memcpy(ni->ni_pmk, pmk->pmk_key, IEEE80211_PMK_LEN);
} else /* use pre-shared key */
memcpy(ni->ni_pmk, ic->ic_psk, IEEE80211_PMK_LEN);
ni->ni_flags |= IEEE80211_NODE_PMK;
/* save authenticator's nonce (ANonce) */
memcpy(ni->ni_nonce, key->nonce, EAPOL_KEY_NONCE_LEN);
/* generate supplicant's nonce (SNonce) */
arc4random_buf(ic->ic_nonce, EAPOL_KEY_NONCE_LEN);
/* TPTK = CalcPTK(PMK, ANonce, SNonce) */
ieee80211_derive_ptk(ni->ni_rsnakms, ni->ni_pmk, ni->ni_macaddr,
ic->ic_myaddr, ni->ni_nonce, ic->ic_nonce, &tptk);
if (ic->ic_if.if_flags & IFF_DEBUG)
printf("%s: received msg %d/%d of the %s handshake from %s\n",
ic->ic_if.if_xname, 1, 4, "4-way",
ether_sprintf(ni->ni_macaddr));
/* send message 2 to authenticator using TPTK */
(void)ieee80211_send_4way_msg2(ic, ni, key->replaycnt, &tptk);
}
#ifndef IEEE80211_STA_ONLY
/*
* Process Message 2 of the 4-Way Handshake (sent by Supplicant).
*/
void
ieee80211_recv_4way_msg2(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni,
const u_int8_t *rsnie)
{
struct ieee80211_ptk tptk;
if (ic->ic_opmode != IEEE80211_M_HOSTAP &&
ic->ic_opmode != IEEE80211_M_IBSS)
return;
/* discard if we're not expecting this message */
if (ni->ni_rsn_state != RSNA_PTKSTART &&
ni->ni_rsn_state != RSNA_PTKCALCNEGOTIATING) {
DPRINTF(("unexpected in state: %d\n", ni->ni_rsn_state));
return;
}
ni->ni_rsn_state = RSNA_PTKCALCNEGOTIATING;
/* NB: replay counter has already been verified by caller */
/* PTK = CalcPTK(ANonce, SNonce) */
ieee80211_derive_ptk(ni->ni_rsnakms, ni->ni_pmk, ic->ic_myaddr,
ni->ni_macaddr, ni->ni_nonce, key->nonce, &tptk);
/* check Key MIC field using KCK */
if (ieee80211_eapol_key_check_mic(key, tptk.kck) != 0) {
DPRINTF(("key MIC failed\n"));
ic->ic_stats.is_rx_eapol_badmic++;
return; /* will timeout.. */
}
timeout_del(&ni->ni_eapol_to);
ni->ni_rsn_state = RSNA_PTKCALCNEGOTIATING_2;
ni->ni_rsn_retries = 0;
/* install TPTK as PTK now that MIC is verified */
memcpy(&ni->ni_ptk, &tptk, sizeof(tptk));
/*
* The RSN IE must match bit-wise with what the STA included in its
* (Re)Association Request.
*/
if (ni->ni_rsnie == NULL || rsnie[1] != ni->ni_rsnie[1] ||
memcmp(rsnie, ni->ni_rsnie, 2 + rsnie[1]) != 0) {
IEEE80211_SEND_MGMT(ic, ni, IEEE80211_FC0_SUBTYPE_DEAUTH,
IEEE80211_REASON_RSN_DIFFERENT_IE);
ieee80211_node_leave(ic, ni);
return;
}
if (ic->ic_if.if_flags & IFF_DEBUG)
printf("%s: received msg %d/%d of the %s handshake from %s\n",
ic->ic_if.if_xname, 2, 4, "4-way",
ether_sprintf(ni->ni_macaddr));
/* send message 3 to supplicant */
(void)ieee80211_send_4way_msg3(ic, ni);
}
#endif /* IEEE80211_STA_ONLY */
/*
* Process Message 3 of the 4-Way Handshake (sent by Authenticator).
*/
void
ieee80211_recv_4way_msg3(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
{
struct ieee80211_ptk tptk;
struct ieee80211_key *k;
const u_int8_t *frm, *efrm;
const u_int8_t *rsnie1, *rsnie2, *gtk, *igtk;
u_int16_t info, reason = 0;
int keylen;
#ifndef IEEE80211_STA_ONLY
if (ic->ic_opmode != IEEE80211_M_STA &&
ic->ic_opmode != IEEE80211_M_IBSS)
return;
#endif
if (ni->ni_replaycnt_ok &&
BE_READ_8(key->replaycnt) <= ni->ni_replaycnt) {
ic->ic_stats.is_rx_eapol_replay++;
return;
}
/* make sure that a PMK has been selected */
if (!(ni->ni_flags & IEEE80211_NODE_PMK)) {
DPRINTF(("no PMK found for %s\n",
ether_sprintf(ni->ni_macaddr)));
return;
}
/* check that ANonce matches that of Message 1 */
if (memcmp(key->nonce, ni->ni_nonce, EAPOL_KEY_NONCE_LEN) != 0) {
DPRINTF(("ANonce does not match msg 1/4\n"));
return;
}
/* TPTK = CalcPTK(PMK, ANonce, SNonce) */
ieee80211_derive_ptk(ni->ni_rsnakms, ni->ni_pmk, ni->ni_macaddr,
ic->ic_myaddr, key->nonce, ic->ic_nonce, &tptk);
info = BE_READ_2(key->info);
/* check Key MIC field using KCK */
if (ieee80211_eapol_key_check_mic(key, tptk.kck) != 0) {
DPRINTF(("key MIC failed\n"));
ic->ic_stats.is_rx_eapol_badmic++;
return;
}
/* install TPTK as PTK now that MIC is verified */
memcpy(&ni->ni_ptk, &tptk, sizeof(tptk));
/* if encrypted, decrypt Key Data field using KEK */
if ((info & EAPOL_KEY_ENCRYPTED) &&
ieee80211_eapol_key_decrypt(key, ni->ni_ptk.kek) != 0) {
DPRINTF(("decryption failed\n"));
return;
}
/* parse key data field */
frm = (const u_int8_t *)&key[1];
efrm = frm + BE_READ_2(key->paylen);
/*
* Some WPA1+WPA2 APs (like hostapd) appear to include both WPA and
* RSN IEs in message 3/4. We only take into account the IE of the
* version of the protocol we negotiated at association time.
*/
rsnie1 = rsnie2 = gtk = igtk = NULL;
while (frm + 2 <= efrm) {
if (frm + 2 + frm[1] > efrm)
break;
switch (frm[0]) {
case IEEE80211_ELEMID_RSN:
if (ni->ni_rsnprotos != IEEE80211_PROTO_RSN)
break;
if (rsnie1 == NULL)
rsnie1 = frm;
else if (rsnie2 == NULL)
rsnie2 = frm;
/* ignore others if more than two RSN IEs */
break;
case IEEE80211_ELEMID_VENDOR:
if (frm[1] < 4)
break;
if (memcmp(&frm[2], IEEE80211_OUI, 3) == 0) {
switch (frm[5]) {
case IEEE80211_KDE_GTK:
gtk = frm;
break;
case IEEE80211_KDE_IGTK:
if (ni->ni_flags & IEEE80211_NODE_MFP)
igtk = frm;
break;
}
} else if (memcmp(&frm[2], MICROSOFT_OUI, 3) == 0) {
switch (frm[5]) {
case 1: /* WPA */
if (ni->ni_rsnprotos !=
IEEE80211_PROTO_WPA)
break;
rsnie1 = frm;
break;
}
}
break;
}
frm += 2 + frm[1];
}
/* first WPA/RSN IE is mandatory */
if (rsnie1 == NULL) {
DPRINTF(("missing RSN IE\n"));
return;
}
/* key data must be encrypted if GTK is included */
if (gtk != NULL && !(info & EAPOL_KEY_ENCRYPTED)) {
DPRINTF(("GTK not encrypted\n"));
return;
}
/* GTK KDE must be included if IGTK KDE is present */
if (igtk != NULL && gtk == NULL) {
DPRINTF(("IGTK KDE found but GTK KDE missing\n"));
return;
}
/* check that the Install bit is set if using pairwise keys */
if (ni->ni_rsncipher != IEEE80211_CIPHER_USEGROUP &&
!(info & EAPOL_KEY_INSTALL)) {
DPRINTF(("pairwise cipher but !Install\n"));
return;
}
/*
* Check that first WPA/RSN IE is identical to the one received in
* the beacon or probe response frame.
*/
if (ni->ni_rsnie == NULL || rsnie1[1] != ni->ni_rsnie[1] ||
memcmp(rsnie1, ni->ni_rsnie, 2 + rsnie1[1]) != 0) {
reason = IEEE80211_REASON_RSN_DIFFERENT_IE;
goto deauth;
}
/*
* If a second RSN information element is present, use its pairwise
* cipher suite or deauthenticate.
*/
if (rsnie2 != NULL) {
struct ieee80211_rsnparams rsn;
if (ieee80211_parse_rsn(ic, rsnie2, &rsn) == 0) {
if (rsn.rsn_akms != ni->ni_rsnakms ||
rsn.rsn_groupcipher != ni->ni_rsngroupcipher ||
rsn.rsn_nciphers != 1 ||
!(rsn.rsn_ciphers & ic->ic_rsnciphers)) {
reason = IEEE80211_REASON_BAD_PAIRWISE_CIPHER;
goto deauth;
}
/* use pairwise cipher suite of second RSN IE */
ni->ni_rsnciphers = rsn.rsn_ciphers;
ni->ni_rsncipher = ni->ni_rsnciphers;
}
}
/* update the last seen value of the key replay counter field */
ni->ni_replaycnt = BE_READ_8(key->replaycnt);
ni->ni_replaycnt_ok = 1;
if (ic->ic_if.if_flags & IFF_DEBUG)
printf("%s: received msg %d/%d of the %s handshake from %s\n",
ic->ic_if.if_xname, 3, 4, "4-way",
ether_sprintf(ni->ni_macaddr));
/* send message 4 to authenticator */
if (ieee80211_send_4way_msg4(ic, ni) != 0)
return; /* ..authenticator will retry */
if (ni->ni_rsncipher != IEEE80211_CIPHER_USEGROUP) {
u_int64_t prsc;
/* check that key length matches that of pairwise cipher */
keylen = ieee80211_cipher_keylen(ni->ni_rsncipher);
if (BE_READ_2(key->keylen) != keylen) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
prsc = (gtk == NULL) ? LE_READ_6(key->rsc) : 0;
/* map PTK to 802.11 key */
k = &ni->ni_pairwise_key;
memset(k, 0, sizeof(*k));
k->k_cipher = ni->ni_rsncipher;
k->k_rsc[0] = prsc;
k->k_len = keylen;
memcpy(k->k_key, ni->ni_ptk.tk, k->k_len);
/* install the PTK */
if ((*ic->ic_set_key)(ic, ni, k) != 0) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
ni->ni_flags &= ~IEEE80211_NODE_TXRXPROT;
ni->ni_flags |= IEEE80211_NODE_RXPROT;
}
if (gtk != NULL) {
u_int8_t kid;
/* check that key length matches that of group cipher */
keylen = ieee80211_cipher_keylen(ni->ni_rsngroupcipher);
if (gtk[1] != 6 + keylen) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
/* map GTK to 802.11 key */
kid = gtk[6] & 3;
k = &ic->ic_nw_keys[kid];
memset(k, 0, sizeof(*k));
k->k_id = kid; /* 0-3 */
k->k_cipher = ni->ni_rsngroupcipher;
k->k_flags = IEEE80211_KEY_GROUP;
if (gtk[6] & (1 << 2))
k->k_flags |= IEEE80211_KEY_TX;
k->k_rsc[0] = LE_READ_6(key->rsc);
k->k_len = keylen;
memcpy(k->k_key, >k[8], k->k_len);
/* install the GTK */
if ((*ic->ic_set_key)(ic, ni, k) != 0) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
}
if (igtk != NULL) { /* implies MFP && gtk != NULL */
u_int16_t kid;
/* check that the IGTK KDE is valid */
if (igtk[1] != 4 + 24) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
kid = LE_READ_2(&igtk[6]);
if (kid != 4 && kid != 5) {
DPRINTF(("unsupported IGTK id %u\n", kid));
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
/* map IGTK to 802.11 key */
k = &ic->ic_nw_keys[kid];
memset(k, 0, sizeof(*k));
k->k_id = kid; /* either 4 or 5 */
k->k_cipher = ni->ni_rsngroupmgmtcipher;
k->k_flags = IEEE80211_KEY_IGTK;
k->k_mgmt_rsc = LE_READ_6(&igtk[8]); /* IPN */
k->k_len = 16;
memcpy(k->k_key, &igtk[14], k->k_len);
/* install the IGTK */
if ((*ic->ic_set_key)(ic, ni, k) != 0) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
}
if (info & EAPOL_KEY_INSTALL)
ni->ni_flags |= IEEE80211_NODE_TXRXPROT;
if (info & EAPOL_KEY_SECURE) {
ni->ni_flags |= IEEE80211_NODE_TXRXPROT;
#ifndef IEEE80211_STA_ONLY
if (ic->ic_opmode != IEEE80211_M_IBSS ||
++ni->ni_key_count == 2)
#endif
{
DPRINTF(("marking port %s valid\n",
ether_sprintf(ni->ni_macaddr)));
ni->ni_port_valid = 1;
}
}
deauth:
if (reason != 0) {
IEEE80211_SEND_MGMT(ic, ni, IEEE80211_FC0_SUBTYPE_DEAUTH,
reason);
ieee80211_new_state(ic, IEEE80211_S_SCAN, -1);
}
}
#ifndef IEEE80211_STA_ONLY
/*
* Process Message 4 of the 4-Way Handshake (sent by Supplicant).
*/
void
ieee80211_recv_4way_msg4(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
{
if (ic->ic_opmode != IEEE80211_M_HOSTAP &&
ic->ic_opmode != IEEE80211_M_IBSS)
return;
/* discard if we're not expecting this message */
if (ni->ni_rsn_state != RSNA_PTKINITNEGOTIATING) {
DPRINTF(("unexpected in state: %d\n", ni->ni_rsn_state));
return;
}
/* NB: replay counter has already been verified by caller */
/* check Key MIC field using KCK */
if (ieee80211_eapol_key_check_mic(key, ni->ni_ptk.kck) != 0) {
DPRINTF(("key MIC failed\n"));
ic->ic_stats.is_rx_eapol_badmic++;
return; /* will timeout.. */
}
timeout_del(&ni->ni_eapol_to);
ni->ni_rsn_state = RSNA_PTKINITDONE;
ni->ni_rsn_retries = 0;
if (ni->ni_rsncipher != IEEE80211_CIPHER_USEGROUP) {
struct ieee80211_key *k;
/* map PTK to 802.11 key */
k = &ni->ni_pairwise_key;
memset(k, 0, sizeof(*k));
k->k_cipher = ni->ni_rsncipher;
k->k_len = ieee80211_cipher_keylen(k->k_cipher);
memcpy(k->k_key, ni->ni_ptk.tk, k->k_len);
/* install the PTK */
if ((*ic->ic_set_key)(ic, ni, k) != 0) {
IEEE80211_SEND_MGMT(ic, ni,
IEEE80211_FC0_SUBTYPE_DEAUTH,
IEEE80211_REASON_ASSOC_TOOMANY);
ieee80211_node_leave(ic, ni);
return;
}
ni->ni_flags |= IEEE80211_NODE_TXRXPROT;
}
if (ic->ic_opmode != IEEE80211_M_IBSS || ++ni->ni_key_count == 2) {
DPRINTF(("marking port %s valid\n",
ether_sprintf(ni->ni_macaddr)));
ni->ni_port_valid = 1;
}
if (ic->ic_if.if_flags & IFF_DEBUG)
printf("%s: received msg %d/%d of the %s handshake from %s\n",
ic->ic_if.if_xname, 4, 4, "4-way",
ether_sprintf(ni->ni_macaddr));
/* initiate a group key handshake for WPA */
if (ni->ni_rsnprotos == IEEE80211_PROTO_WPA)
(void)ieee80211_send_group_msg1(ic, ni);
else
ni->ni_rsn_gstate = RSNA_IDLE;
}
/*
* Differentiate Message 2 from Message 4 of the 4-Way Handshake based on
* the presence of an RSN or WPA Information Element.
*/
void
ieee80211_recv_4way_msg2or4(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
{
const u_int8_t *frm, *efrm;
const u_int8_t *rsnie;
if (BE_READ_8(key->replaycnt) != ni->ni_replaycnt) {
ic->ic_stats.is_rx_eapol_replay++;
return;
}
/* parse key data field (check if an RSN IE is present) */
frm = (const u_int8_t *)&key[1];
efrm = frm + BE_READ_2(key->paylen);
rsnie = NULL;
while (frm + 2 <= efrm) {
if (frm + 2 + frm[1] > efrm)
break;
switch (frm[0]) {
case IEEE80211_ELEMID_RSN:
rsnie = frm;
break;
case IEEE80211_ELEMID_VENDOR:
if (frm[1] < 4)
break;
if (memcmp(&frm[2], MICROSOFT_OUI, 3) == 0) {
switch (frm[5]) {
case 1: /* WPA */
rsnie = frm;
break;
}
}
}
frm += 2 + frm[1];
}
if (rsnie != NULL)
ieee80211_recv_4way_msg2(ic, key, ni, rsnie);
else
ieee80211_recv_4way_msg4(ic, key, ni);
}
#endif /* IEEE80211_STA_ONLY */
/*
* Process Message 1 of the RSN Group Key Handshake (sent by Authenticator).
*/
void
ieee80211_recv_rsn_group_msg1(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
{
struct ieee80211_key *k;
const u_int8_t *frm, *efrm;
const u_int8_t *gtk, *igtk;
u_int16_t info, kid, reason = 0;
int keylen;
#ifndef IEEE80211_STA_ONLY
if (ic->ic_opmode != IEEE80211_M_STA &&
ic->ic_opmode != IEEE80211_M_IBSS)
return;
#endif
if (BE_READ_8(key->replaycnt) <= ni->ni_replaycnt) {
ic->ic_stats.is_rx_eapol_replay++;
return;
}
/* check Key MIC field using KCK */
if (ieee80211_eapol_key_check_mic(key, ni->ni_ptk.kck) != 0) {
DPRINTF(("key MIC failed\n"));
ic->ic_stats.is_rx_eapol_badmic++;
return;
}
info = BE_READ_2(key->info);
/* check that encrypted and decrypt Key Data field using KEK */
if (!(info & EAPOL_KEY_ENCRYPTED) ||
ieee80211_eapol_key_decrypt(key, ni->ni_ptk.kek) != 0) {
DPRINTF(("decryption failed\n"));
return;
}
/* parse key data field (shall contain a GTK KDE) */
frm = (const u_int8_t *)&key[1];
efrm = frm + BE_READ_2(key->paylen);
gtk = igtk = NULL;
while (frm + 2 <= efrm) {
if (frm + 2 + frm[1] > efrm)
break;
switch (frm[0]) {
case IEEE80211_ELEMID_VENDOR:
if (frm[1] < 4)
break;
if (memcmp(&frm[2], IEEE80211_OUI, 3) == 0) {
switch (frm[5]) {
case IEEE80211_KDE_GTK:
gtk = frm;
break;
case IEEE80211_KDE_IGTK:
if (ni->ni_flags & IEEE80211_NODE_MFP)
igtk = frm;
break;
}
}
break;
}
frm += 2 + frm[1];
}
/* check that the GTK KDE is present */
if (gtk == NULL) {
DPRINTF(("GTK KDE missing\n"));
return;
}
/* check that key length matches that of group cipher */
keylen = ieee80211_cipher_keylen(ni->ni_rsngroupcipher);
if (gtk[1] != 6 + keylen)
return;
/* map GTK to 802.11 key */
kid = gtk[6] & 3;
k = &ic->ic_nw_keys[kid];
memset(k, 0, sizeof(*k));
k->k_id = kid; /* 0-3 */
k->k_cipher = ni->ni_rsngroupcipher;
k->k_flags = IEEE80211_KEY_GROUP;
if (gtk[6] & (1 << 2))
k->k_flags |= IEEE80211_KEY_TX;
k->k_rsc[0] = LE_READ_6(key->rsc);
k->k_len = keylen;
/* install the GTK */
if ((*ic->ic_set_key)(ic, ni, k) != 0) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
if (igtk != NULL) { /* implies MFP */
/* check that the IGTK KDE is valid */
if (igtk[1] != 4 + 24) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
kid = LE_READ_2(&igtk[6]);
if (kid != 4 && kid != 5) {
DPRINTF(("unsupported IGTK id %u\n", kid));
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
/* map IGTK to 802.11 key */
k = &ic->ic_nw_keys[kid];
memset(k, 0, sizeof(*k));
k->k_id = kid; /* either 4 or 5 */
k->k_cipher = ni->ni_rsngroupmgmtcipher;
k->k_flags = IEEE80211_KEY_IGTK;
k->k_mgmt_rsc = LE_READ_6(&igtk[8]); /* IPN */
k->k_len = 16;
memcpy(k->k_key, &igtk[14], k->k_len);
/* install the IGTK */
if ((*ic->ic_set_key)(ic, ni, k) != 0) {
reason = IEEE80211_REASON_AUTH_LEAVE;
goto deauth;
}
}
if (info & EAPOL_KEY_SECURE) {
#ifndef IEEE80211_STA_ONLY
if (ic->ic_opmode != IEEE80211_M_IBSS ||
++ni->ni_key_count == 2)
#endif
{
DPRINTF(("marking port %s valid\n",
ether_sprintf(ni->ni_macaddr)));
ni->ni_port_valid = 1;
}
}
/* update the last seen value of the key replay counter field */
ni->ni_replaycnt = BE_READ_8(key->replaycnt);
if (ic->ic_if.if_flags & IFF_DEBUG)
printf("%s: received msg %d/%d of the %s handshake from %s\n",
ic->ic_if.if_xname, 1, 2, "group key",
ether_sprintf(ni->ni_macaddr));
/* send message 2 to authenticator */
(void)ieee80211_send_group_msg2(ic, ni, NULL);
return;
deauth:
IEEE80211_SEND_MGMT(ic, ni, IEEE80211_FC0_SUBTYPE_DEAUTH, reason);
ieee80211_new_state(ic, IEEE80211_S_SCAN, -1);
}
/*
* Process Message 1 of the WPA Group Key Handshake (sent by Authenticator).
*/
void
ieee80211_recv_wpa_group_msg1(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
{
struct ieee80211_key *k;
u_int16_t info;
u_int8_t kid;
int keylen;
#ifndef IEEE80211_STA_ONLY
if (ic->ic_opmode != IEEE80211_M_STA &&
ic->ic_opmode != IEEE80211_M_IBSS)
return;
#endif
if (BE_READ_8(key->replaycnt) <= ni->ni_replaycnt) {
ic->ic_stats.is_rx_eapol_replay++;
return;
}
/* check Key MIC field using KCK */
if (ieee80211_eapol_key_check_mic(key, ni->ni_ptk.kck) != 0) {
DPRINTF(("key MIC failed\n"));
ic->ic_stats.is_rx_eapol_badmic++;
return;
}
/*
* EAPOL-Key data field is encrypted even though WPA doesn't set
* the ENCRYPTED bit in the info field.
*/
if (ieee80211_eapol_key_decrypt(key, ni->ni_ptk.kek) != 0) {
DPRINTF(("decryption failed\n"));
return;
}
/* check that key length matches that of group cipher */
keylen = ieee80211_cipher_keylen(ni->ni_rsngroupcipher);
if (BE_READ_2(key->keylen) != keylen)
return;
/* check that the data length is large enough to hold the key */
if (BE_READ_2(key->paylen) < keylen)
return;
info = BE_READ_2(key->info);
/* map GTK to 802.11 key */
kid = (info >> EAPOL_KEY_WPA_KID_SHIFT) & 3;
k = &ic->ic_nw_keys[kid];
memset(k, 0, sizeof(*k));
k->k_id = kid; /* 0-3 */
k->k_cipher = ni->ni_rsngroupcipher;
k->k_flags = IEEE80211_KEY_GROUP;
if (info & EAPOL_KEY_WPA_TX)
k->k_flags |= IEEE80211_KEY_TX;
k->k_rsc[0] = LE_READ_6(key->rsc);
k->k_len = keylen;
/* key data field contains the GTK */
memcpy(k->k_key, &key[1], k->k_len);
/* install the GTK */
if ((*ic->ic_set_key)(ic, ni, k) != 0) {
IEEE80211_SEND_MGMT(ic, ni, IEEE80211_FC0_SUBTYPE_DEAUTH,
IEEE80211_REASON_AUTH_LEAVE);
ieee80211_new_state(ic, IEEE80211_S_SCAN, -1);
return;
}
if (info & EAPOL_KEY_SECURE) {
#ifndef IEEE80211_STA_ONLY
if (ic->ic_opmode != IEEE80211_M_IBSS ||
++ni->ni_key_count == 2)
#endif
{
DPRINTF(("marking port %s valid\n",
ether_sprintf(ni->ni_macaddr)));
ni->ni_port_valid = 1;
}
}
/* update the last seen value of the key replay counter field */
ni->ni_replaycnt = BE_READ_8(key->replaycnt);
if (ic->ic_if.if_flags & IFF_DEBUG)
printf("%s: received msg %d/%d of the %s handshake from %s\n",
ic->ic_if.if_xname, 1, 2, "group key",
ether_sprintf(ni->ni_macaddr));
/* send message 2 to authenticator */
(void)ieee80211_send_group_msg2(ic, ni, k);
}
#ifndef IEEE80211_STA_ONLY
/*
* Process Message 2 of the Group Key Handshake (sent by Supplicant).
*/
void
ieee80211_recv_group_msg2(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
{
if (ic->ic_opmode != IEEE80211_M_HOSTAP &&
ic->ic_opmode != IEEE80211_M_IBSS)
return;
/* discard if we're not expecting this message */
if (ni->ni_rsn_gstate != RSNA_REKEYNEGOTIATING) {
DPRINTF(("%s: unexpected in state: %d\n", ni->ni_rsn_gstate));
return;
}
if (BE_READ_8(key->replaycnt) != ni->ni_replaycnt) {
ic->ic_stats.is_rx_eapol_replay++;
return;
}
/* check Key MIC field using KCK */
if (ieee80211_eapol_key_check_mic(key, ni->ni_ptk.kck) != 0) {
DPRINTF(("key MIC failed\n"));
ic->ic_stats.is_rx_eapol_badmic++;
return;
}
timeout_del(&ni->ni_eapol_to);
ni->ni_rsn_gstate = RSNA_REKEYESTABLISHED;
if ((ni->ni_flags & IEEE80211_NODE_REKEY) &&
--ic->ic_rsn_keydonesta == 0)
ieee80211_setkeysdone(ic);
ni->ni_flags &= ~IEEE80211_NODE_REKEY;
ni->ni_flags |= IEEE80211_NODE_TXRXPROT;
ni->ni_rsn_gstate = RSNA_IDLE;
ni->ni_rsn_retries = 0;
if (ic->ic_if.if_flags & IFF_DEBUG)
printf("%s: received msg %d/%d of the %s handshake from %s\n",
ic->ic_if.if_xname, 2, 2, "group key",
ether_sprintf(ni->ni_macaddr));
}
/*
* EAPOL-Key Request frames are sent by the supplicant to request that the
* authenticator initiates either a 4-Way Handshake or Group Key Handshake,
* or to report a MIC failure in a TKIP MSDU.
*/
void
ieee80211_recv_eapol_key_req(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, struct ieee80211_node *ni)
{
u_int16_t info;
if (ic->ic_opmode != IEEE80211_M_HOSTAP &&
ic->ic_opmode != IEEE80211_M_IBSS)
return;
/* enforce monotonicity of key request replay counter */
if (ni->ni_reqreplaycnt_ok &&
BE_READ_8(key->replaycnt) <= ni->ni_reqreplaycnt) {
ic->ic_stats.is_rx_eapol_replay++;
return;
}
info = BE_READ_2(key->info);
if (!(info & EAPOL_KEY_KEYMIC) ||
ieee80211_eapol_key_check_mic(key, ni->ni_ptk.kck) != 0) {
DPRINTF(("key request MIC failed\n"));
ic->ic_stats.is_rx_eapol_badmic++;
return;
}
/* update key request replay counter now that MIC is verified */
ni->ni_reqreplaycnt = BE_READ_8(key->replaycnt);
ni->ni_reqreplaycnt_ok = 1;
if (info & EAPOL_KEY_ERROR) { /* TKIP MIC failure */
/* ignore reports from STAs not using TKIP */
if (ic->ic_bss->ni_rsngroupcipher != IEEE80211_CIPHER_TKIP &&
ni->ni_rsncipher != IEEE80211_CIPHER_TKIP) {
DPRINTF(("MIC failure report from !TKIP STA: %s\n",
ether_sprintf(ni->ni_macaddr)));
return;
}
ic->ic_stats.is_rx_remmicfail++;
ieee80211_michael_mic_failure(ic, LE_READ_6(key->rsc));
} else if (info & EAPOL_KEY_PAIRWISE) {
/* initiate a 4-Way Handshake */
} else {
/*
* Should change the GTK, initiate the 4-Way Handshake and
* then execute a Group Key Handshake with all supplicants.
*/
}
}
#endif /* IEEE80211_STA_ONLY */