freebsd-dev/contrib/hostapd/pmksa_cache.c
2007-07-09 16:15:06 +00:00

367 lines
9.2 KiB
C

/*
* hostapd - PMKSA cache for IEEE 802.11i RSN
* Copyright (c) 2004-2006, 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 "hostapd.h"
#include "common.h"
#include "wpa.h"
#include "eloop.h"
#include "sha1.h"
#include "ieee802_1x.h"
#include "eapol_sm.h"
#include "pmksa_cache.h"
static const int pmksa_cache_max_entries = 1024;
static const int dot11RSNAConfigPMKLifetime = 43200;
struct rsn_pmksa_cache {
#define PMKID_HASH_SIZE 128
#define PMKID_HASH(pmkid) (unsigned int) ((pmkid)[0] & 0x7f)
struct rsn_pmksa_cache_entry *pmkid[PMKID_HASH_SIZE];
struct rsn_pmksa_cache_entry *pmksa;
int pmksa_count;
void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx);
void *ctx;
};
/**
* rsn_pmkid - Calculate PMK identifier
* @pmk: Pairwise master key
* @pmk_len: Length of pmk in bytes
* @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)
*/
void rsn_pmkid(const u8 *pmk, size_t pmk_len, const u8 *aa, const u8 *spa,
u8 *pmkid)
{
char *title = "PMK Name";
const u8 *addr[3];
const size_t len[3] = { 8, ETH_ALEN, ETH_ALEN };
unsigned char hash[SHA1_MAC_LEN];
addr[0] = (u8 *) 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 rsn_pmksa_cache *pmksa);
static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
{
if (entry == NULL)
return;
free(entry->identity);
ieee802_1x_free_radius_class(&entry->radius_class);
free(entry);
}
static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
struct rsn_pmksa_cache_entry *entry)
{
struct rsn_pmksa_cache_entry *pos, *prev;
pmksa->pmksa_count--;
pmksa->free_cb(entry, pmksa->ctx);
pos = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
prev = NULL;
while (pos) {
if (pos == entry) {
if (prev != NULL) {
prev->hnext = pos->hnext;
} else {
pmksa->pmkid[PMKID_HASH(entry->pmkid)] =
pos->hnext;
}
break;
}
prev = pos;
pos = pos->hnext;
}
pos = pmksa->pmksa;
prev = NULL;
while (pos) {
if (pos == entry) {
if (prev != NULL)
prev->next = pos->next;
else
pmksa->pmksa = pos->next;
break;
}
prev = pos;
pos = pos->next;
}
_pmksa_cache_free_entry(entry);
}
static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
{
struct rsn_pmksa_cache *pmksa = eloop_ctx;
struct os_time now;
os_get_time(&now);
while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
pmksa->pmksa = entry->next;
wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
MACSTR, MAC2STR(entry->spa));
pmksa_cache_free_entry(pmksa, entry);
}
pmksa_cache_set_expiration(pmksa);
}
static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
{
int sec;
struct os_time now;
eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
if (pmksa->pmksa == NULL)
return;
os_get_time(&now);
sec = pmksa->pmksa->expiration - now.sec;
if (sec < 0)
sec = 0;
eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
}
static void pmksa_cache_from_eapol_data(struct rsn_pmksa_cache_entry *entry,
struct eapol_state_machine *eapol)
{
if (eapol == NULL)
return;
if (eapol->identity) {
entry->identity = malloc(eapol->identity_len);
if (entry->identity) {
entry->identity_len = eapol->identity_len;
memcpy(entry->identity, eapol->identity,
eapol->identity_len);
}
}
ieee802_1x_copy_radius_class(&entry->radius_class,
&eapol->radius_class);
entry->eap_type_authsrv = eapol->eap_type_authsrv;
entry->vlan_id = eapol->sta->vlan_id;
}
void pmksa_cache_to_eapol_data(struct rsn_pmksa_cache_entry *entry,
struct eapol_state_machine *eapol)
{
if (entry == NULL || eapol == NULL)
return;
if (entry->identity) {
free(eapol->identity);
eapol->identity = malloc(entry->identity_len);
if (eapol->identity) {
eapol->identity_len = entry->identity_len;
memcpy(eapol->identity, entry->identity,
entry->identity_len);
}
wpa_hexdump_ascii(MSG_DEBUG, "STA identity from PMKSA",
eapol->identity, eapol->identity_len);
}
ieee802_1x_free_radius_class(&eapol->radius_class);
ieee802_1x_copy_radius_class(&eapol->radius_class,
&entry->radius_class);
if (eapol->radius_class.attr) {
wpa_printf(MSG_DEBUG, "Copied %lu Class attribute(s) from "
"PMKSA", (unsigned long) eapol->radius_class.count);
}
eapol->eap_type_authsrv = entry->eap_type_authsrv;
eapol->sta->vlan_id = entry->vlan_id;
}
/**
* pmksa_cache_add - Add a PMKSA cache entry
* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
* @pmk: The new pairwise master key
* @pmk_len: PMK length in bytes, usually PMK_LEN (32)
* @aa: Authenticator address
* @spa: Supplicant address
* @session_timeout: Session timeout
* @eapol: Pointer to EAPOL state machine data
* 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 Supplicant,
* this entry will be replaced with the new entry. PMKID will be calculated
* based on the PMK.
*/
struct rsn_pmksa_cache_entry *
pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
const u8 *aa, const u8 *spa, int session_timeout,
struct eapol_state_machine *eapol)
{
struct rsn_pmksa_cache_entry *entry, *pos, *prev;
struct os_time now;
if (pmk_len > PMK_LEN)
return NULL;
entry = wpa_zalloc(sizeof(*entry));
if (entry == NULL)
return NULL;
memcpy(entry->pmk, pmk, pmk_len);
entry->pmk_len = pmk_len;
rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid);
os_get_time(&now);
entry->expiration = now.sec;
if (session_timeout > 0)
entry->expiration += session_timeout;
else
entry->expiration += dot11RSNAConfigPMKLifetime;
entry->akmp = WPA_KEY_MGMT_IEEE8021X;
memcpy(entry->spa, spa, ETH_ALEN);
pmksa_cache_from_eapol_data(entry, eapol);
/* Replace an old entry for the same STA (if found) with the new entry
*/
pos = pmksa_cache_get(pmksa, spa, NULL);
if (pos)
pmksa_cache_free_entry(pmksa, pos);
if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
/* Remove the oldest entry to make room for the new entry */
wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
"entry (for " MACSTR ") to make room for new one",
MAC2STR(pmksa->pmksa->spa));
pmksa_cache_free_entry(pmksa, pmksa->pmksa);
}
/* Add the new entry; order by expiration time */
pos = pmksa->pmksa;
prev = NULL;
while (pos) {
if (pos->expiration > entry->expiration)
break;
prev = pos;
pos = pos->next;
}
if (prev == NULL) {
entry->next = pmksa->pmksa;
pmksa->pmksa = entry;
} else {
entry->next = prev->next;
prev->next = entry;
}
entry->hnext = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
pmksa->pmkid[PMKID_HASH(entry->pmkid)] = entry;
pmksa->pmksa_count++;
wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
MAC2STR(entry->spa));
wpa_hexdump(MSG_DEBUG, "RSN: added PMKID", entry->pmkid, PMKID_LEN);
return entry;
}
/**
* pmksa_cache_deinit - Free all entries in PMKSA cache
* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
*/
void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
{
struct rsn_pmksa_cache_entry *entry, *prev;
int i;
if (pmksa == NULL)
return;
entry = pmksa->pmksa;
while (entry) {
prev = entry;
entry = entry->next;
_pmksa_cache_free_entry(prev);
}
eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
for (i = 0; i < PMKID_HASH_SIZE; i++)
pmksa->pmkid[i] = NULL;
free(pmksa);
}
/**
* pmksa_cache_get - Fetch a PMKSA cache entry
* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
* @spa: Supplicant 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_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
const u8 *spa, const u8 *pmkid)
{
struct rsn_pmksa_cache_entry *entry;
if (pmkid)
entry = pmksa->pmkid[PMKID_HASH(pmkid)];
else
entry = pmksa->pmksa;
while (entry) {
if ((spa == NULL || memcmp(entry->spa, spa, ETH_ALEN) == 0) &&
(pmkid == NULL ||
memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
return entry;
entry = pmkid ? entry->hnext : entry->next;
}
return NULL;
}
/**
* pmksa_cache_init - Initialize PMKSA cache
* @free_cb: Callback function to be called when a PMKSA cache entry is freed
* @ctx: Context pointer for free_cb function
* Returns: Pointer to PMKSA cache data or %NULL on failure
*/
struct rsn_pmksa_cache *
pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
void *ctx), void *ctx)
{
struct rsn_pmksa_cache *pmksa;
pmksa = wpa_zalloc(sizeof(*pmksa));
if (pmksa) {
pmksa->free_cb = free_cb;
pmksa->ctx = ctx;
}
return pmksa;
}