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freebsd/contrib/wpa_supplicant/preauth.c
2006-03-07 05:26:33 +00:00

935 lines
25 KiB
C

/*
* WPA Supplicant - RSN pre-authentication and PMKSA caching
* Copyright (c) 2003-2006, Jouni Malinen <jkmaline@cc.hut.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 <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#ifndef CONFIG_NATIVE_WINDOWS
#include <netinet/in.h>
#endif /* CONFIG_NATIVE_WINDOWS */
#include <string.h>
#include <time.h>
#include "common.h"
#include "sha1.h"
#include "wpa.h"
#include "driver.h"
#include "eloop.h"
#include "wpa_supplicant.h"
#include "config.h"
#include "l2_packet.h"
#include "eapol_sm.h"
#include "preauth.h"
#include "wpa_i.h"
#define PMKID_CANDIDATE_PRIO_SCAN 1000
static const int pmksa_cache_max_entries = 32;
struct rsn_pmksa_candidate {
struct rsn_pmksa_candidate *next;
u8 bssid[ETH_ALEN];
int priority;
};
/**
* rsn_pmkid - Calculate PMK identifier
* @pmk: Pairwise master key
* @aa: Authenticator address
* @spa: Supplicant address
*
* IEEE Std 802.11i-2004 - 8.5.1.2 Pairwise key hierarchy
* PMKID = HMAC-SHA1-128(PMK, "PMK Name" || AA || SPA)
*/
static void rsn_pmkid(const u8 *pmk, const u8 *aa, const u8 *spa, u8 *pmkid)
{
char *title = "PMK Name";
const unsigned char *addr[3];
const size_t len[3] = { 8, ETH_ALEN, ETH_ALEN };
unsigned char hash[SHA1_MAC_LEN];
addr[0] = (unsigned char *) title;
addr[1] = aa;
addr[2] = spa;
hmac_sha1_vector(pmk, PMK_LEN, 3, addr, len, hash);
memcpy(pmkid, hash, PMKID_LEN);
}
static void pmksa_cache_set_expiration(struct wpa_sm *sm);
static void pmksa_cache_free_entry(struct wpa_sm *sm,
struct rsn_pmksa_cache *entry, int replace)
{
int current;
current = sm->cur_pmksa == entry ||
(sm->pmk_len == entry->pmk_len &&
memcmp(sm->pmk, entry->pmk, sm->pmk_len) == 0);
free(entry);
sm->pmksa_count--;
if (current) {
wpa_printf(MSG_DEBUG, "RSN: removed current PMKSA entry");
sm->cur_pmksa = NULL;
if (replace) {
/* A new entry is being added, so no need to
* deauthenticate in this case. This happens when EAP
* authentication is completed again (reauth or failed
* PMKSA caching attempt). */
return;
}
memset(sm->pmk, 0, sizeof(sm->pmk));
wpa_sm_deauthenticate(sm, REASON_UNSPECIFIED);
wpa_sm_req_scan(sm, 0, 0);
}
}
static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
{
struct wpa_sm *sm = eloop_ctx;
time_t now;
time(&now);
while (sm->pmksa && sm->pmksa->expiration <= now) {
struct rsn_pmksa_cache *entry = sm->pmksa;
sm->pmksa = entry->next;
wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
MACSTR, MAC2STR(entry->aa));
pmksa_cache_free_entry(sm, entry, 0);
}
pmksa_cache_set_expiration(sm);
}
static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
{
struct wpa_sm *sm = eloop_ctx;
sm->cur_pmksa = NULL;
eapol_sm_request_reauth(sm->eapol);
}
static void pmksa_cache_set_expiration(struct wpa_sm *sm)
{
int sec;
struct rsn_pmksa_cache *entry;
eloop_cancel_timeout(pmksa_cache_expire, sm, NULL);
eloop_cancel_timeout(pmksa_cache_reauth, sm, NULL);
if (sm->pmksa == NULL)
return;
sec = sm->pmksa->expiration - time(NULL);
if (sec < 0)
sec = 0;
eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, sm, NULL);
entry = sm->cur_pmksa ? sm->cur_pmksa :
pmksa_cache_get(sm, sm->bssid, NULL);
if (entry) {
sec = sm->pmksa->reauth_time - time(NULL);
if (sec < 0)
sec = 0;
eloop_register_timeout(sec, 0, pmksa_cache_reauth, sm, NULL);
}
}
/**
* pmksa_cache_add - Add a PMKSA cache entry
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @pmk: The new pairwise master key
* @pmk_len: PMK length in bytes, usually PMK_LEN (32)
* @aa: Authenticator address
* @spa: Supplicant address
* @ssid: The network configuration for which this PMK is being added
* Returns: Pointer to the added PMKSA cache entry or %NULL on error
*
* This function create a PMKSA entry for a new PMK and adds it to the PMKSA
* cache. If an old entry is already in the cache for the same Authenticator,
* this entry will be replaced with the new entry. PMKID will be calculated
* based on the PMK and the driver interface is notified of the new PMKID.
*/
struct rsn_pmksa_cache *
pmksa_cache_add(struct wpa_sm *sm, const u8 *pmk,
size_t pmk_len, const u8 *aa, const u8 *spa,
struct wpa_ssid *ssid)
{
struct rsn_pmksa_cache *entry, *pos, *prev;
time_t now;
if (sm->proto != WPA_PROTO_RSN || pmk_len > PMK_LEN)
return NULL;
entry = malloc(sizeof(*entry));
if (entry == NULL)
return NULL;
memset(entry, 0, sizeof(*entry));
memcpy(entry->pmk, pmk, pmk_len);
entry->pmk_len = pmk_len;
rsn_pmkid(pmk, aa, spa, entry->pmkid);
now = time(NULL);
entry->expiration = now + sm->dot11RSNAConfigPMKLifetime;
entry->reauth_time = now + sm->dot11RSNAConfigPMKLifetime *
sm->dot11RSNAConfigPMKReauthThreshold / 100;
entry->akmp = WPA_KEY_MGMT_IEEE8021X;
memcpy(entry->aa, aa, ETH_ALEN);
entry->ssid = ssid;
/* Replace an old entry for the same Authenticator (if found) with the
* new entry */
pos = sm->pmksa;
prev = NULL;
while (pos) {
if (memcmp(aa, pos->aa, ETH_ALEN) == 0) {
if (pos->pmk_len == pmk_len &&
memcmp(pos->pmk, pmk, pmk_len) == 0 &&
memcmp(pos->pmkid, entry->pmkid, PMKID_LEN) == 0) {
wpa_printf(MSG_DEBUG, "WPA: reusing previous "
"PMKSA entry");
free(entry);
return pos;
}
if (prev == NULL)
sm->pmksa = pos->next;
else
prev->next = pos->next;
wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
"the current AP");
pmksa_cache_free_entry(sm, pos, 1);
break;
}
prev = pos;
pos = pos->next;
}
if (sm->pmksa_count >= pmksa_cache_max_entries && sm->pmksa) {
/* Remove the oldest entry to make room for the new entry */
pos = sm->pmksa;
sm->pmksa = pos->next;
wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
"entry (for " MACSTR ") to make room for new one",
MAC2STR(pos->aa));
wpa_sm_remove_pmkid(sm, pos->aa, pos->pmkid);
pmksa_cache_free_entry(sm, pos, 0);
}
/* Add the new entry; order by expiration time */
pos = sm->pmksa;
prev = NULL;
while (pos) {
if (pos->expiration > entry->expiration)
break;
prev = pos;
pos = pos->next;
}
if (prev == NULL) {
entry->next = sm->pmksa;
sm->pmksa = entry;
pmksa_cache_set_expiration(sm);
} else {
entry->next = prev->next;
prev->next = entry;
}
sm->pmksa_count++;
wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
MAC2STR(entry->aa));
wpa_sm_add_pmkid(sm, entry->aa, entry->pmkid);
return entry;
}
/**
* pmksa_cache_free - Free all entries in PMKSA cache
* @sm: Pointer to WPA state machine data from wpa_sm_init()
*/
void pmksa_cache_free(struct wpa_sm *sm)
{
struct rsn_pmksa_cache *entry, *prev;
if (sm == NULL)
return;
entry = sm->pmksa;
sm->pmksa = NULL;
while (entry) {
prev = entry;
entry = entry->next;
free(prev);
}
pmksa_cache_set_expiration(sm);
sm->cur_pmksa = NULL;
}
/**
* pmksa_cache_get - Fetch a PMKSA cache entry
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @aa: Authenticator address or %NULL to match any
* @pmkid: PMKID or %NULL to match any
* Returns: Pointer to PMKSA cache entry or %NULL if no match was found
*/
struct rsn_pmksa_cache * pmksa_cache_get(struct wpa_sm *sm,
const u8 *aa, const u8 *pmkid)
{
struct rsn_pmksa_cache *entry = sm->pmksa;
while (entry) {
if ((aa == NULL || memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
(pmkid == NULL ||
memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
return entry;
entry = entry->next;
}
return NULL;
}
/**
* pmksa_cache_notify_reconfig - Reconfiguration notification for PMKSA cache
* @sm: Pointer to WPA state machine data from wpa_sm_init()
*
* Clear references to old data structures when wpa_supplicant is reconfigured.
*/
void pmksa_cache_notify_reconfig(struct wpa_sm *sm)
{
struct rsn_pmksa_cache *entry = sm->pmksa;
while (entry) {
entry->ssid = NULL;
entry = entry->next;
}
}
static struct rsn_pmksa_cache *
pmksa_cache_clone_entry(struct wpa_sm *sm,
const struct rsn_pmksa_cache *old_entry, const u8 *aa)
{
struct rsn_pmksa_cache *new_entry;
new_entry = pmksa_cache_add(sm, old_entry->pmk, old_entry->pmk_len,
aa, sm->own_addr, old_entry->ssid);
if (new_entry == NULL)
return NULL;
/* TODO: reorder entries based on expiration time? */
new_entry->expiration = old_entry->expiration;
new_entry->opportunistic = 1;
return new_entry;
}
/**
* pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @ssid: Pointer to the current network configuration
* @aa: Authenticator address for the new AP
* Returns: Pointer to a new PMKSA cache entry or %NULL if not available
*
* Try to create a new PMKSA cache entry opportunistically by guessing that the
* new AP is sharing the same PMK as another AP that has the same SSID and has
* already an entry in PMKSA cache.
*/
static struct rsn_pmksa_cache *
pmksa_cache_get_opportunistic(struct wpa_sm *sm,
struct wpa_ssid *ssid, const u8 *aa)
{
struct rsn_pmksa_cache *entry = sm->pmksa;
if (ssid == NULL)
return NULL;
while (entry) {
if (entry->ssid == ssid) {
entry = pmksa_cache_clone_entry(sm, entry, aa);
if (entry) {
wpa_printf(MSG_DEBUG, "RSN: added "
"opportunistic PMKSA cache entry "
"for " MACSTR, MAC2STR(aa));
}
return entry;
}
entry = entry->next;
}
return NULL;
}
/**
* pmksa_cache_get_current - Get the current used PMKSA entry
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* Returns: Pointer to the current PMKSA cache entry or %NULL if not available
*/
struct rsn_pmksa_cache * pmksa_cache_get_current(struct wpa_sm *sm)
{
if (sm == NULL)
return NULL;
return sm->cur_pmksa;
}
/**
* pmksa_cache_clear_current - Clear the current PMKSA entry selection
* @sm: Pointer to WPA state machine data from wpa_sm_init()
*/
void pmksa_cache_clear_current(struct wpa_sm *sm)
{
if (sm == NULL)
return;
sm->cur_pmksa = NULL;
}
/**
* pmksa_cache_set_current - Set the current PMKSA entry selection
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @pmkid: PMKID for selecting PMKSA or %NULL if not used
* @bssid: BSSID for PMKSA or %NULL if not used
* @ssid: The network configuration for the current network
* @try_opportunistic: Whether to allow opportunistic PMKSA caching
* Returns: 0 if PMKSA was found or -1 if no matching entry was found
*/
int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
const u8 *bssid, struct wpa_ssid *ssid,
int try_opportunistic)
{
sm->cur_pmksa = NULL;
if (pmkid)
sm->cur_pmksa = pmksa_cache_get(sm, NULL, pmkid);
if (sm->cur_pmksa == NULL && bssid)
sm->cur_pmksa = pmksa_cache_get(sm, bssid, NULL);
if (sm->cur_pmksa == NULL && try_opportunistic)
sm->cur_pmksa = pmksa_cache_get_opportunistic(sm, ssid, bssid);
if (sm->cur_pmksa) {
wpa_hexdump(MSG_DEBUG, "RSN: PMKID",
sm->cur_pmksa->pmkid, PMKID_LEN);
return 0;
}
return -1;
}
/**
* pmksa_cache_list - Dump text list of entries in PMKSA cache
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @buf: Buffer for the list
* @len: Length of the buffer
* Returns: number of bytes written to buffer
*
* This function is used to generate a text format representation of the
* current PMKSA cache contents for the ctrl_iface PMKSA command.
*/
int pmksa_cache_list(struct wpa_sm *sm, char *buf, size_t len)
{
int i, j;
char *pos = buf;
struct rsn_pmksa_cache *entry;
time_t now;
time(&now);
pos += snprintf(pos, buf + len - pos,
"Index / AA / PMKID / expiration (in seconds) / "
"opportunistic\n");
i = 0;
entry = sm->pmksa;
while (entry) {
i++;
pos += snprintf(pos, buf + len - pos, "%d " MACSTR " ",
i, MAC2STR(entry->aa));
for (j = 0; j < PMKID_LEN; j++)
pos += snprintf(pos, buf + len - pos, "%02x",
entry->pmkid[j]);
pos += snprintf(pos, buf + len - pos, " %d %d\n",
(int) (entry->expiration - now),
entry->opportunistic);
entry = entry->next;
}
return pos - buf;
}
/**
* 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;
free(prev);
}
}
#ifdef IEEE8021X_EAPOL
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 ||
memcmp(sm->preauth_bssid, "\x00\x00\x00\x00\x00\x00",
ETH_ALEN) == 0 ||
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);
#ifdef EAP_LEAP
if (res) {
res = eapol_sm_get_key(eapol, pmk, 16);
pmk_len = 16;
}
#endif /* EAP_LEAP */
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, pmk, pmk_len,
sm->preauth_bssid, sm->own_addr,
sm->cur_ssid);
} else {
wpa_msg(sm->ctx->ctx, MSG_INFO, "RSN: failed to get "
"master session key from pre-auth EAPOL state "
"machines");
success = 0;
}
}
wpa_msg(sm->ctx->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->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);
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
* @config: Current network 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 wpa_ssid *config)
{
struct eapol_config eapol_conf;
struct eapol_ctx *ctx;
if (sm->preauth_eapol)
return -1;
wpa_msg(sm->ctx->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;
}
ctx = malloc(sizeof(*ctx));
if (ctx == NULL) {
wpa_printf(MSG_WARNING, "Failed to allocate EAPOL context.");
return -4;
}
memset(ctx, 0, sizeof(*ctx));
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) {
free(ctx);
wpa_printf(MSG_WARNING, "RSN: Failed to initialize EAPOL "
"state machines for pre-authentication");
return -3;
}
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;
if (config)
eapol_conf.workaround = config->eap_workaround;
eapol_sm_notify_config(sm->preauth_eapol, config, &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);
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;
memset(sm->preauth_bssid, 0, ETH_ALEN);
l2_packet_deinit(sm->l2_preauth);
sm->l2_preauth = 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->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) {
wpa_msg(sm->ctx->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 *p = NULL;
candidate = sm->pmksa_candidates;
p = pmksa_cache_get(sm, candidate->bssid, NULL);
if (memcmp(sm->bssid, candidate->bssid, ETH_ALEN) != 0 &&
(p == NULL || p->opportunistic)) {
wpa_msg(sm->ctx->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->cur_ssid);
free(candidate);
return;
}
wpa_msg(sm->ctx->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;
free(candidate);
}
wpa_msg(sm->ctx->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->cur_ssid && sm->cur_ssid->proactive_key_caching)
pmksa_cache_get_opportunistic(sm, sm->cur_ssid, 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 (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 = malloc(sizeof(*cand));
if (cand == NULL)
return;
memset(cand, 0, sizeof(*cand));
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->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 - Process scan results to find PMKSA candidates
* @sm: Pointer to WPA state machine data from wpa_sm_init()
* @results: Scan results
* @count: Number of BSSes in scan results
*
* This functions goes through the scan results and adds all suitable APs
* (Authenticators) into PMKSA candidate list.
*/
void rsn_preauth_scan_results(struct wpa_sm *sm,
struct wpa_scan_result *results, int count)
{
struct wpa_scan_result *r;
struct wpa_ie_data ie;
int i;
struct rsn_pmksa_cache *pmksa;
if (sm->cur_ssid == NULL)
return;
/*
* TODO: is it ok to free all candidates? What about the entries
* received from EVENT_PMKID_CANDIDATE?
*/
pmksa_candidate_free(sm);
for (i = count - 1; i >= 0; i--) {
r = &results[i];
if (r->ssid_len != sm->cur_ssid->ssid_len ||
memcmp(r->ssid, sm->cur_ssid->ssid,
r->ssid_len) != 0)
continue;
if (memcmp(r->bssid, sm->bssid, ETH_ALEN) == 0)
continue;
if (r->rsn_ie_len == 0 ||
wpa_parse_wpa_ie(r->rsn_ie, r->rsn_ie_len, &ie))
continue;
pmksa = pmksa_cache_get(sm, r->bssid, NULL);
if (pmksa &&
(!pmksa->opportunistic ||
!(ie.capabilities & WPA_CAPABILITY_PREAUTH)))
continue;
/*
* Give less priority to candidates found from normal
* scan results.
*/
pmksa_candidate_add(sm, r->bssid,
PMKID_CANDIDATE_PRIO_SCAN,
ie.capabilities & WPA_CAPABILITY_PREAUTH);
}
}
/**
* 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;
if (sm->preauth_eapol) {
pos += snprintf(pos, end - pos, "Pre-authentication "
"EAPOL state machines:\n");
res = eapol_sm_get_status(sm->preauth_eapol,
pos, end - pos, verbose);
if (res >= 0)
pos += res;
}
return pos - buf;
}
/**
* 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 */