hostap/src/rsn_supp/preauth.c

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/*
* WPA Supplicant - RSN pre-authentication
* Copyright (c) 2003-2009, Jouni Malinen <j@w1.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include "common.h"
#include "wpa.h"
#include "eloop.h"
#include "l2_packet/l2_packet.h"
#include "eapol_supp/eapol_supp_sm.h"
#include "preauth.h"
#include "pmksa_cache.h"
#include "wpa_i.h"
#include "ieee802_11_defs.h"
#if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2)
#define PMKID_CANDIDATE_PRIO_SCAN 1000
struct rsn_pmksa_candidate {
struct rsn_pmksa_candidate *next;
u8 bssid[ETH_ALEN];
int priority;
};
/**
* pmksa_candidate_free - Free all entries in PMKSA candidate list
* @sm: Pointer to WPA state machine data from wpa_sm_init()
*/
void pmksa_candidate_free(struct wpa_sm *sm)
{
struct rsn_pmksa_candidate *entry, *prev;
if (sm == NULL)
return;
entry = sm->pmksa_candidates;
sm->pmksa_candidates = NULL;
while (entry) {
prev = entry;
entry = entry->next;
os_free(prev);
}
}
static void rsn_preauth_receive(void *ctx, const u8 *src_addr,
const u8 *buf, size_t len)
{
struct wpa_sm *sm = ctx;
wpa_printf(MSG_DEBUG, "RX pre-auth from " MACSTR, MAC2STR(src_addr));
wpa_hexdump(MSG_MSGDUMP, "RX pre-auth", buf, len);
if (sm->preauth_eapol == NULL ||
is_zero_ether_addr(sm->preauth_bssid) ||
os_memcmp(sm->preauth_bssid, src_addr, ETH_ALEN) != 0) {
wpa_printf(MSG_WARNING, "RSN pre-auth frame received from "
"unexpected source " MACSTR " - dropped",
MAC2STR(src_addr));
return;
}
eapol_sm_rx_eapol(sm->preauth_eapol, src_addr, buf, len);
}
static void rsn_preauth_eapol_cb(struct eapol_sm *eapol, int success,
void *ctx)
{
struct wpa_sm *sm = ctx;
u8 pmk[PMK_LEN];
if (success) {
int res, pmk_len;
pmk_len = PMK_LEN;
res = eapol_sm_get_key(eapol, pmk, PMK_LEN);
if (res) {
/*
* EAP-LEAP is an exception from other EAP methods: it
* uses only 16-byte PMK.
*/
res = eapol_sm_get_key(eapol, pmk, 16);
pmk_len = 16;
}
if (res == 0) {
wpa_hexdump_key(MSG_DEBUG, "RSN: PMK from pre-auth",
pmk, pmk_len);
sm->pmk_len = pmk_len;
pmksa_cache_add(sm->pmksa, pmk, pmk_len,
sm->preauth_bssid, sm->own_addr,
sm->network_ctx,
WPA_KEY_MGMT_IEEE8021X);
} else {
wpa_msg(sm->ctx->msg_ctx, MSG_INFO,
"RSN: failed to get master session key from "
"pre-auth EAPOL state machines");
success = 0;
}
}
wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
MACSTR " %s", MAC2STR(sm->preauth_bssid),
success ? "completed successfully" : "failed");
rsn_preauth_deinit(sm);
rsn_preauth_candidate_process(sm);
}
static void rsn_preauth_timeout(void *eloop_ctx, void *timeout_ctx)
{
struct wpa_sm *sm = eloop_ctx;
wpa_msg(sm->ctx->msg_ctx, MSG_INFO, "RSN: pre-authentication with "
MACSTR " timed out", MAC2STR(sm->preauth_bssid));
rsn_preauth_deinit(sm);
rsn_preauth_candidate_process(sm);
}
static int rsn_preauth_eapol_send(void *ctx, int type, const u8 *buf,
size_t len)
{
struct wpa_sm *sm = ctx;
u8 *msg;
size_t msglen;
int res;
/* TODO: could add l2_packet_sendmsg that allows fragments to avoid
* extra copy here */
if (sm->l2_preauth == NULL)
return -1;
msg = wpa_sm_alloc_eapol(sm, type, buf, len, &msglen, NULL);
if (msg == NULL)
return -1;
wpa_hexdump(MSG_MSGDUMP, "TX EAPOL (preauth)", msg, msglen);
res = l2_packet_send(sm->l2_preauth, sm->preauth_bssid,
ETH_P_RSN_PREAUTH, msg, msglen);
os_free(msg);
return res;
}
/**
* rsn_preauth_init - Start new RSN pre-authentication
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @dst: Authenticator address (BSSID) with which to preauthenticate
* @eap_conf: Current EAP configuration
* Returns: 0 on success, -1 on another pre-authentication is in progress,
* -2 on layer 2 packet initialization failure, -3 on EAPOL state machine
* initialization failure, -4 on memory allocation failure
*
* This function request an RSN pre-authentication with a given destination
* address. This is usually called for PMKSA candidates found from scan results
* or from driver reports. In addition, ctrl_iface PREAUTH command can trigger
* pre-authentication.
*/
int rsn_preauth_init(struct wpa_sm *sm, const u8 *dst,
struct eap_peer_config *eap_conf)
{
struct eapol_config eapol_conf;
struct eapol_ctx *ctx;
if (sm->preauth_eapol)
return -1;
wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG,
"RSN: starting pre-authentication with " MACSTR, MAC2STR(dst));
sm->l2_preauth = l2_packet_init(sm->ifname, sm->own_addr,
ETH_P_RSN_PREAUTH,
rsn_preauth_receive, sm, 0);
if (sm->l2_preauth == NULL) {
wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 packet "
"processing for pre-authentication");
return -2;
}
if (sm->bridge_ifname) {
sm->l2_preauth_br = l2_packet_init(sm->bridge_ifname,
sm->own_addr,
ETH_P_RSN_PREAUTH,
rsn_preauth_receive, sm, 0);
if (sm->l2_preauth_br == NULL) {
wpa_printf(MSG_WARNING, "RSN: Failed to initialize L2 "
"packet processing (bridge) for "
"pre-authentication");
return -2;
}
}
ctx = os_zalloc(sizeof(*ctx));
if (ctx == NULL) {
wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context.");
return -4;
}
ctx->ctx = sm->ctx->ctx;
ctx->msg_ctx = sm->ctx->ctx;
ctx->preauth = 1;
ctx->cb = rsn_preauth_eapol_cb;
ctx->cb_ctx = sm;
ctx->scard_ctx = sm->scard_ctx;
ctx->eapol_send = rsn_preauth_eapol_send;
ctx->eapol_send_ctx = sm;
ctx->set_config_blob = sm->ctx->set_config_blob;
ctx->get_config_blob = sm->ctx->get_config_blob;
sm->preauth_eapol = eapol_sm_init(ctx);
if (sm->preauth_eapol == NULL) {
os_free(ctx);
wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL "
"state machines for pre-authentication");
return -3;
}
os_memset(&eapol_conf, 0, sizeof(eapol_conf));
eapol_conf.accept_802_1x_keys = 0;
eapol_conf.required_keys = 0;
eapol_conf.fast_reauth = sm->fast_reauth;
eapol_conf.workaround = sm->eap_workaround;
eapol_sm_notify_config(sm->preauth_eapol, eap_conf, &eapol_conf);
/*
* Use a shorter startPeriod with preauthentication since the first
* preauth EAPOL-Start frame may end up being dropped due to race
* condition in the AP between the data receive and key configuration
* after the 4-Way Handshake.
*/
eapol_sm_configure(sm->preauth_eapol, -1, -1, 5, 6);
os_memcpy(sm->preauth_bssid, dst, ETH_ALEN);
eapol_sm_notify_portValid(sm->preauth_eapol, TRUE);
/* 802.1X::portControl = Auto */
eapol_sm_notify_portEnabled(sm->preauth_eapol, TRUE);
eloop_register_timeout(sm->dot11RSNAConfigSATimeout, 0,
rsn_preauth_timeout, sm, NULL);
return 0;
}
/**
* rsn_preauth_deinit - Abort RSN pre-authentication
* @sm: Pointer to WPA state machine data from wpa_sm_init()
*
* This function aborts the current RSN pre-authentication (if one is started)
* and frees resources allocated for it.
*/
void rsn_preauth_deinit(struct wpa_sm *sm)
{
if (sm == NULL || !sm->preauth_eapol)
return;
eloop_cancel_timeout(rsn_preauth_timeout, sm, NULL);
eapol_sm_deinit(sm->preauth_eapol);
sm->preauth_eapol = NULL;
os_memset(sm->preauth_bssid, 0, ETH_ALEN);
l2_packet_deinit(sm->l2_preauth);
sm->l2_preauth = NULL;
if (sm->l2_preauth_br) {
l2_packet_deinit(sm->l2_preauth_br);
sm->l2_preauth_br = NULL;
}
}
/**
* rsn_preauth_candidate_process - Process PMKSA candidates
* @sm: Pointer to WPA state machine data from wpa_sm_init()
*
* Go through the PMKSA candidates and start pre-authentication if a candidate
* without an existing PMKSA cache entry is found. Processed candidates will be
* removed from the list.
*/
void rsn_preauth_candidate_process(struct wpa_sm *sm)
{
struct rsn_pmksa_candidate *candidate;
if (sm->pmksa_candidates == NULL)
return;
/* TODO: drop priority for old candidate entries */
wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: processing PMKSA candidate "
"list");
if (sm->preauth_eapol ||
sm->proto != WPA_PROTO_RSN ||
wpa_sm_get_state(sm) != WPA_COMPLETED ||
(sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X &&
sm->key_mgmt != WPA_KEY_MGMT_IEEE8021X_SHA256)) {
wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: not in suitable "
"state for new pre-authentication");
return; /* invalid state for new pre-auth */
}
while (sm->pmksa_candidates) {
struct rsn_pmksa_cache_entry *p = NULL;
candidate = sm->pmksa_candidates;
p = pmksa_cache_get(sm->pmksa, candidate->bssid, NULL);
if (os_memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 &&
(p == NULL || p->opportunistic)) {
wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA "
"candidate " MACSTR
" selected for pre-authentication",
MAC2STR(candidate->bssid));
sm->pmksa_candidates = candidate->next;
rsn_preauth_init(sm, candidate->bssid,
sm->eap_conf_ctx);
os_free(candidate);
return;
}
wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: PMKSA candidate "
MACSTR " does not need pre-authentication anymore",
MAC2STR(candidate->bssid));
/* Some drivers (e.g., NDIS) expect to get notified about the
* PMKIDs again, so report the existing data now. */
if (p) {
wpa_sm_add_pmkid(sm, candidate->bssid, p->pmkid);
}
sm->pmksa_candidates = candidate->next;
os_free(candidate);
}
wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: no more pending PMKSA "
"candidates");
}
/**
* pmksa_candidate_add - Add a new PMKSA candidate
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @bssid: BSSID (authenticator address) of the candidate
* @prio: Priority (the smaller number, the higher priority)
* @preauth: Whether the candidate AP advertises support for pre-authentication
*
* This function is used to add PMKSA candidates for RSN pre-authentication. It
* is called from scan result processing and from driver events for PMKSA
* candidates, i.e., EVENT_PMKID_CANDIDATE events to wpa_supplicant_event().
*/
void pmksa_candidate_add(struct wpa_sm *sm, const u8 *bssid,
int prio, int preauth)
{
struct rsn_pmksa_candidate *cand, *prev, *pos;
if (sm->network_ctx && sm->proactive_key_caching)
pmksa_cache_get_opportunistic(sm->pmksa, sm->network_ctx,
bssid);
if (!preauth) {
wpa_printf(MSG_DEBUG, "RSN: Ignored PMKID candidate without "
"preauth flag");
return;
}
/* If BSSID already on candidate list, update the priority of the old
* entry. Do not override priority based on normal scan results. */
prev = NULL;
cand = sm->pmksa_candidates;
while (cand) {
if (os_memcmp(cand->bssid, bssid, ETH_ALEN) == 0) {
if (prev)
prev->next = cand->next;
else
sm->pmksa_candidates = cand->next;
break;
}
prev = cand;
cand = cand->next;
}
if (cand) {
if (prio < PMKID_CANDIDATE_PRIO_SCAN)
cand->priority = prio;
} else {
cand = os_zalloc(sizeof(*cand));
if (cand == NULL)
return;
os_memcpy(cand->bssid, bssid, ETH_ALEN);
cand->priority = prio;
}
/* Add candidate to the list; order by increasing priority value. i.e.,
* highest priority (smallest value) first. */
prev = NULL;
pos = sm->pmksa_candidates;
while (pos) {
if (cand->priority <= pos->priority)
break;
prev = pos;
pos = pos->next;
}
cand->next = pos;
if (prev)
prev->next = cand;
else
sm->pmksa_candidates = cand;
wpa_msg(sm->ctx->msg_ctx, MSG_DEBUG, "RSN: added PMKSA cache "
"candidate " MACSTR " prio %d", MAC2STR(bssid), prio);
rsn_preauth_candidate_process(sm);
}
/* TODO: schedule periodic scans if current AP supports preauth */
/**
* rsn_preauth_scan_results - Start processing scan results for canditates
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* Returns: 0 if ready to process results or -1 to skip processing
*
* This functions is used to notify RSN code about start of new scan results
* processing. The actual scan results will be provided by calling
* rsn_preauth_scan_result() for each BSS if this function returned 0.
*/
int rsn_preauth_scan_results(struct wpa_sm *sm)
{
if (sm->ssid_len == 0)
return -1;
/*
* TODO: is it ok to free all candidates? What about the entries
* received from EVENT_PMKID_CANDIDATE?
*/
pmksa_candidate_free(sm);
return 0;
}
/**
* rsn_preauth_scan_result - Processing scan result for PMKSA canditates
* @sm: Pointer to WPA state machine data from wpa_sm_init()
*
* Add all suitable APs (Authenticators) from scan results into PMKSA
* candidate list.
*/
void rsn_preauth_scan_result(struct wpa_sm *sm, const u8 *bssid,
const u8 *ssid, const u8 *rsn)
{
struct wpa_ie_data ie;
struct rsn_pmksa_cache_entry *pmksa;
if (ssid[1] != sm->ssid_len ||
os_memcmp(ssid + 2, sm->ssid, sm->ssid_len) != 0)
return; /* Not for the current SSID */
if (os_memcmp(bssid, sm->bssid, ETH_ALEN) == 0)
return; /* Ignore current AP */
if (wpa_parse_wpa_ie(rsn, 2 + rsn[1], &ie))
return;
pmksa = pmksa_cache_get(sm->pmksa, bssid, NULL);
if (pmksa && (!pmksa->opportunistic ||
!(ie.capabilities & WPA_CAPABILITY_PREAUTH)))
return;
/* Give less priority to candidates found from normal scan results. */
pmksa_candidate_add(sm, bssid, PMKID_CANDIDATE_PRIO_SCAN,
ie.capabilities & WPA_CAPABILITY_PREAUTH);
}
#ifdef CONFIG_CTRL_IFACE
/**
* rsn_preauth_get_status - Get pre-authentication status
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @buf: Buffer for status information
* @buflen: Maximum buffer length
* @verbose: Whether to include verbose status information
* Returns: Number of bytes written to buf.
*
* Query WPA2 pre-authentication for status information. This function fills in
* a text area with current status information. If the buffer (buf) is not
* large enough, status information will be truncated to fit the buffer.
*/
int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
int verbose)
{
char *pos = buf, *end = buf + buflen;
int res, ret;
if (sm->preauth_eapol) {
ret = os_snprintf(pos, end - pos, "Pre-authentication "
"EAPOL state machines:\n");
if (ret < 0 || ret >= end - pos)
return pos - buf;
pos += ret;
res = eapol_sm_get_status(sm->preauth_eapol,
pos, end - pos, verbose);
if (res >= 0)
pos += res;
}
return pos - buf;
}
#endif /* CONFIG_CTRL_IFACE */
/**
* rsn_preauth_in_progress - Verify whether pre-authentication is in progress
* @sm: Pointer to WPA state machine data from wpa_sm_init()
*/
int rsn_preauth_in_progress(struct wpa_sm *sm)
{
return sm->preauth_eapol != NULL;
}
#endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */