/* * hostapd - PMKSA cache for IEEE 802.11i RSN * Copyright (c) 2004-2008, Jouni Malinen * * 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 "sha256.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 * @pmkid: Buffer for PMKID * @use_sha256: Whether to use SHA256-based KDF * * 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, int use_sha256) { char *title = "PMK Name"; const u8 *addr[3]; const size_t len[3] = { 8, ETH_ALEN, ETH_ALEN }; unsigned char hash[SHA256_MAC_LEN]; addr[0] = (u8 *) title; addr[1] = aa; addr[2] = spa; #ifdef CONFIG_IEEE80211W if (use_sha256) hmac_sha256_vector(pmk, pmk_len, 3, addr, len, hash); else #endif /* CONFIG_IEEE80211W */ 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 * @akmp: WPA_KEY_MGMT_* used in key derivation * 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, int akmp) { 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, wpa_key_mgmt_sha256(akmp)); os_get_time(&now); entry->expiration = now.sec; if (session_timeout > 0) entry->expiration += session_timeout; else entry->expiration += dot11RSNAConfigPMKLifetime; entry->akmp = akmp; 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() * @aa: Authenticator address * @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, wpa_key_mgmt_sha256(entry->akmp)); 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; }