hostap/hostapd/pmksa_cache.c
Jouni Malinen bf98f7f3bc Added support for opportunistic key caching (OKC)
This allows hostapd to share the PMKSA caches internally when multiple
BSSes or radios are being controlled by the same hostapd process.
2008-08-03 20:17:58 +03:00

443 lines
11 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 "common.h"
#include "ap.h"
#include "config.h"
#include "common.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);
os_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;
os_free(entry->identity);
ieee802_1x_free_radius_class(&entry->radius_class);
os_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 = os_malloc(eapol->identity_len);
if (entry->identity) {
entry->identity_len = eapol->identity_len;
os_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) {
os_free(eapol->identity);
eapol->identity = os_malloc(entry->identity_len);
if (eapol->identity) {
eapol->identity_len = entry->identity_len;
os_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;
}
static void pmksa_cache_link_entry(struct rsn_pmksa_cache *pmksa,
struct rsn_pmksa_cache_entry *entry)
{
struct rsn_pmksa_cache_entry *pos, *prev;
/* 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);
}
/**
* 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;
struct os_time now;
if (pmk_len > PMK_LEN)
return NULL;
entry = os_zalloc(sizeof(*entry));
if (entry == NULL)
return NULL;
os_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;
os_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);
}
pmksa_cache_link_entry(pmksa, entry);
return entry;
}
struct rsn_pmksa_cache_entry *
pmksa_cache_add_okc(struct rsn_pmksa_cache *pmksa,
const struct rsn_pmksa_cache_entry *old_entry,
const u8 *aa, const u8 *pmkid)
{
struct rsn_pmksa_cache_entry *entry;
entry = os_zalloc(sizeof(*entry));
if (entry == NULL)
return NULL;
os_memcpy(entry->pmkid, pmkid, PMKID_LEN);
os_memcpy(entry->pmk, old_entry->pmk, old_entry->pmk_len);
entry->pmk_len = old_entry->pmk_len;
entry->expiration = old_entry->expiration;
entry->akmp = old_entry->akmp;
os_memcpy(entry->spa, old_entry->spa, ETH_ALEN);
entry->opportunistic = 1;
if (old_entry->identity) {
entry->identity = os_malloc(old_entry->identity_len);
if (entry->identity) {
entry->identity_len = old_entry->identity_len;
os_memcpy(entry->identity, old_entry->identity,
old_entry->identity_len);
}
}
ieee802_1x_copy_radius_class(&entry->radius_class,
&old_entry->radius_class);
entry->eap_type_authsrv = old_entry->eap_type_authsrv;
entry->vlan_id = old_entry->vlan_id;
entry->opportunistic = 1;
pmksa_cache_link_entry(pmksa, entry);
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;
os_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 ||
os_memcmp(entry->spa, spa, ETH_ALEN) == 0) &&
(pmkid == NULL ||
os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
return entry;
entry = pmkid ? entry->hnext : entry->next;
}
return NULL;
}
/**
* pmksa_cache_get_okc - Fetch a PMKSA cache entry using OKC
* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
* @spa: Supplicant address
* @pmkid: PMKID
* Returns: Pointer to PMKSA cache entry or %NULL if no match was found
*
* Use opportunistic key caching (OKC) to find a PMK for a supplicant.
*/
struct rsn_pmksa_cache_entry * pmksa_cache_get_okc(
struct rsn_pmksa_cache *pmksa, const u8 *aa, const u8 *spa,
const u8 *pmkid)
{
struct rsn_pmksa_cache_entry *entry;
u8 new_pmkid[PMKID_LEN];
entry = pmksa->pmksa;
while (entry) {
if (os_memcmp(entry->spa, spa, ETH_ALEN) != 0)
continue;
rsn_pmkid(entry->pmk, entry->pmk_len, aa, spa, new_pmkid);
if (os_memcmp(new_pmkid, pmkid, PMKID_LEN) == 0)
return entry;
entry = 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 = os_zalloc(sizeof(*pmksa));
if (pmksa) {
pmksa->free_cb = free_cb;
pmksa->ctx = ctx;
}
return pmksa;
}