text: /*
   * WPA Supplicant - RSN PMKSA cache
   * Copyright (c) 2004-2009, 2011-2015, Jouni Malinen <j@w1.fi>
   *
   * This software may be distributed under the terms of the BSD license.
   * See README for more details.
   */
  
  #include "includes.h"
  
  #include "common.h"
  #include "eloop.h"
  #include "eapol_supp/eapol_supp_sm.h"
  #include "wpa.h"
  #include "wpa_i.h"
  #include "pmksa_cache.h"
  
  #if (defined(IEEE8021X_EAPOL) || defined(CONFIG_SAE)) && !defined(CONFIG_NO_WPA)
  
  static const int pmksa_cache_max_entries = 32;
  
  struct rsn_pmksa_cache {
  	struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */
  	int pmksa_count; /* number of entries in PMKSA cache */
  	struct wpa_sm *sm; /* TODO: get rid of this reference(?) */
  
  	void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx,
  			enum pmksa_free_reason reason);
  	void *ctx;
  };
  
  
  static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
  
  
  static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
  {
  	bin_clear_free(entry, sizeof(*entry));
  }
  
  
  static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
  				   struct rsn_pmksa_cache_entry *entry,
  				   enum pmksa_free_reason reason)
  {
  	wpa_sm_remove_pmkid(pmksa->sm, entry->aa, entry->pmkid);
  	pmksa->pmksa_count--;
  	pmksa->free_cb(entry, pmksa->ctx, reason);
  	_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_reltime now;
  
  	os_get_reltime(&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->aa));
  		pmksa_cache_free_entry(pmksa, entry, PMKSA_EXPIRE);
  	}
  
  	pmksa_cache_set_expiration(pmksa);
  }
  
  
  static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
  {
  	struct rsn_pmksa_cache *pmksa = eloop_ctx;
  	pmksa->sm->cur_pmksa = NULL;
  	eapol_sm_request_reauth(pmksa->sm->eapol);
  }
  
  
  static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
  {
  	int sec;
  	struct rsn_pmksa_cache_entry *entry;
  	struct os_reltime now;
  
  	eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
  	eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
  	if (pmksa->pmksa == NULL)
  		return;
  	os_get_reltime(&now);
  	sec = pmksa->pmksa->expiration - now.sec;
  	if (sec < 0)
  		sec = 0;
  	eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
  
  	entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
  		pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL, NULL);
  	if (entry) {
  		sec = pmksa->pmksa->reauth_time - now.sec;
  		if (sec < 0)
  			sec = 0;
  		eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
  				       NULL);
  	}
  }
  
  
  /**
   * 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)
   * @pmkid: Calculated PMKID
   * @kck: Key confirmation key or %NULL if not yet derived
   * @kck_len: KCK length in bytes
   * @aa: Authenticator address
   * @spa: Supplicant address
   * @network_ctx: Network configuration context for this PMK
   * @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 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_entry *
  pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
  		const u8 *pmkid, const u8 *kck, size_t kck_len,
  		const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
  {
  	struct rsn_pmksa_cache_entry *entry, *pos, *prev;
  	struct os_reltime now;
  
  	if (pmk_len > PMK_LEN_MAX)
  		return NULL;
  
  	if (wpa_key_mgmt_suite_b(akmp) && !kck)
  		return NULL;
  
  	entry = os_zalloc(sizeof(*entry));
  	if (entry == NULL)
  		return NULL;
  	os_memcpy(entry->pmk, pmk, pmk_len);
  	entry->pmk_len = pmk_len;
  	if (pmkid)
  		os_memcpy(entry->pmkid, pmkid, PMKID_LEN);
  	else if (akmp == WPA_KEY_MGMT_IEEE8021X_SUITE_B_192)
  		rsn_pmkid_suite_b_192(kck, kck_len, aa, spa, entry->pmkid);
  	else if (wpa_key_mgmt_suite_b(akmp))
  		rsn_pmkid_suite_b(kck, kck_len, aa, spa, entry->pmkid);
  	else
  		rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
  			  wpa_key_mgmt_sha256(akmp));
  	os_get_reltime(&now);
  	entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
  	entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
  		pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
  	entry->akmp = akmp;
  	os_memcpy(entry->aa, aa, ETH_ALEN);
  	entry->network_ctx = network_ctx;
  
  	/* Replace an old entry for the same Authenticator (if found) with the
  	 * new entry */
  	pos = pmksa->pmksa;
  	prev = NULL;
  	while (pos) {
  		if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
  			if (pos->pmk_len == pmk_len &&
  			    os_memcmp_const(pos->pmk, pmk, pmk_len) == 0 &&
  			    os_memcmp_const(pos->pmkid, entry->pmkid,
  					    PMKID_LEN) == 0) {
  				wpa_printf(MSG_DEBUG, "WPA: reusing previous "
  					   "PMKSA entry");
  				os_free(entry);
  				return pos;
  			}
  			if (prev == NULL)
  				pmksa->pmksa = pos->next;
  			else
  				prev->next = pos->next;
  
  			/*
  			 * If OKC is used, there may be other PMKSA cache
  			 * entries based on the same PMK. These needs to be
  			 * flushed so that a new entry can be created based on
  			 * the new PMK. Only clear other entries if they have a
  			 * matching PMK and this PMK has been used successfully
  			 * with the current AP, i.e., if opportunistic flag has
  			 * been cleared in wpa_supplicant_key_neg_complete().
  			 */
  			wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
  				   "the current AP and any PMKSA cache entry "
  				   "that was based on the old PMK");
  			if (!pos->opportunistic)
  				pmksa_cache_flush(pmksa, network_ctx, pos->pmk,
  						  pos->pmk_len);
  			pmksa_cache_free_entry(pmksa, pos, PMKSA_REPLACE);
  			break;
  		}
  		prev = pos;
  		pos = pos->next;
  	}
  
  	if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
  		/* Remove the oldest entry to make room for the new entry */
  		pos = pmksa->pmksa;
  
  		if (pos == pmksa->sm->cur_pmksa) {
  			/*
  			 * Never remove the current PMKSA cache entry, since
  			 * it's in use, and removing it triggers a needless
  			 * deauthentication.
  			 */
  			pos = pos->next;
  			pmksa->pmksa->next = pos ? pos->next : NULL;
  		} else
  			pmksa->pmksa = pos->next;
  
  		if (pos) {
  			wpa_printf(MSG_DEBUG, "RSN: removed the oldest idle "
  				   "PMKSA cache entry (for " MACSTR ") to "
  				   "make room for new one",
  				   MAC2STR(pos->aa));
  			pmksa_cache_free_entry(pmksa, pos, PMKSA_FREE);
  		}
  	}
  
  	/* 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;
  		pmksa_cache_set_expiration(pmksa);
  	} else {
  		entry->next = prev->next;
  		prev->next = entry;
  	}
  	pmksa->pmksa_count++;
  	wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR
  		   " network_ctx=%p", MAC2STR(entry->aa), network_ctx);
  	wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
  
  	return entry;
  }
  
  
  /**
   * pmksa_cache_flush - Flush PMKSA cache entries for a specific network
   * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
   * @network_ctx: Network configuration context or %NULL to flush all entries
   * @pmk: PMK to match for or %NYLL to match all PMKs
   * @pmk_len: PMK length
   */
  void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx,
  		       const u8 *pmk, size_t pmk_len)
  {
  	struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp;
  	int removed = 0;
  
  	entry = pmksa->pmksa;
  	while (entry) {
  		if ((entry->network_ctx == network_ctx ||
  		     network_ctx == NULL) &&
  		    (pmk == NULL ||
  		     (pmk_len == entry->pmk_len &&
  		      os_memcmp(pmk, entry->pmk, pmk_len) == 0))) {
  			wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry "
  				   "for " MACSTR, MAC2STR(entry->aa));
  			if (prev)
  				prev->next = entry->next;
  			else
  				pmksa->pmksa = entry->next;
  			tmp = entry;
  			entry = entry->next;
  			pmksa_cache_free_entry(pmksa, tmp, PMKSA_FREE);
  			removed++;
  		} else {
  			prev = entry;
  			entry = entry->next;
  		}
  	}
  	if (removed)
  		pmksa_cache_set_expiration(pmksa);
  }
  
  
  /**
   * 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;
  
  	if (pmksa == NULL)
  		return;
  
  	entry = pmksa->pmksa;
  	pmksa->pmksa = NULL;
  	while (entry) {
  		prev = entry;
  		entry = entry->next;
  		os_free(prev);
  	}
  	pmksa_cache_set_expiration(pmksa);
  	os_free(pmksa);
  }
  
  
  /**
   * pmksa_cache_get - Fetch a PMKSA cache entry
   * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
   * @aa: Authenticator address or %NULL to match any
   * @pmkid: PMKID or %NULL to match any
   * @network_ctx: Network context 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 *aa, const u8 *pmkid,
  					       const void *network_ctx)
  {
  	struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
  	while (entry) {
  		if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
  		    (pmkid == NULL ||
  		     os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) &&
  		    (network_ctx == NULL || network_ctx == entry->network_ctx))
  			return entry;
  		entry = entry->next;
  	}
  	return NULL;
  }
  
  
  static struct rsn_pmksa_cache_entry *
  pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
  			const struct rsn_pmksa_cache_entry *old_entry,
  			const u8 *aa)
  {
  	struct rsn_pmksa_cache_entry *new_entry;
  
  	new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
  				    NULL, NULL, 0,
  				    aa, pmksa->sm->own_addr,
  				    old_entry->network_ctx, old_entry->akmp);
  	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
   * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
   * @network_ctx: Network configuration context
   * @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.
   */
  struct rsn_pmksa_cache_entry *
  pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
  			      const u8 *aa)
  {
  	struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
  
  	wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa));
  	if (network_ctx == NULL)
  		return NULL;
  	while (entry) {
  		if (entry->network_ctx == network_ctx) {
  			entry = pmksa_cache_clone_entry(pmksa, 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_entry * 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
   * @network_ctx: Network configuration context
   * @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, void *network_ctx,
  			    int try_opportunistic)
  {
  	struct rsn_pmksa_cache *pmksa = sm->pmksa;
  	wpa_printf(MSG_DEBUG, "RSN: PMKSA cache search - network_ctx=%p "
  		   "try_opportunistic=%d", network_ctx, try_opportunistic);
  	if (pmkid)
  		wpa_hexdump(MSG_DEBUG, "RSN: Search for PMKID",
  			    pmkid, PMKID_LEN);
  	if (bssid)
  		wpa_printf(MSG_DEBUG, "RSN: Search for BSSID " MACSTR,
  			   MAC2STR(bssid));
  
  	sm->cur_pmksa = NULL;
  	if (pmkid)
  		sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid,
  						network_ctx);
  	if (sm->cur_pmksa == NULL && bssid)
  		sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL,
  						network_ctx);
  	if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
  		sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
  							      network_ctx,
  							      bssid);
  	if (sm->cur_pmksa) {
  		wpa_hexdump(MSG_DEBUG, "RSN: PMKSA cache entry found - PMKID",
  			    sm->cur_pmksa->pmkid, PMKID_LEN);
  		return 0;
  	}
  	wpa_printf(MSG_DEBUG, "RSN: No PMKSA cache entry found");
  	return -1;
  }
  
  
  /**
   * pmksa_cache_list - Dump text list of entries in PMKSA cache
   * @pmksa: Pointer to PMKSA cache data from pmksa_cache_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 rsn_pmksa_cache *pmksa, char *buf, size_t len)
  {
  	int i, ret;
  	char *pos = buf;
  	struct rsn_pmksa_cache_entry *entry;
  	struct os_reltime now;
  
  	os_get_reltime(&now);
  	ret = os_snprintf(pos, buf + len - pos,
  			  "Index / AA / PMKID / expiration (in seconds) / "
  			  "opportunistic\n");
  	if (os_snprintf_error(buf + len - pos, ret))
  		return pos - buf;
  	pos += ret;
  	i = 0;
  	entry = pmksa->pmksa;
  	while (entry) {
  		i++;
  		ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
  				  i, MAC2STR(entry->aa));
  		if (os_snprintf_error(buf + len - pos, ret))
  			return pos - buf;
  		pos += ret;
  		pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
  					PMKID_LEN);
  		ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
  				  (int) (entry->expiration - now.sec),
  				  entry->opportunistic);
  		if (os_snprintf_error(buf + len - pos, ret))
  			return pos - buf;
  		pos += ret;
  		entry = entry->next;
  	}
  	return pos - buf;
  }
  
  
  /**
   * 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
   * @sm: Pointer to WPA state machine data from wpa_sm_init()
   * 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, enum pmksa_free_reason reason),
  		 void *ctx, struct wpa_sm *sm)
  {
  	struct rsn_pmksa_cache *pmksa;
  
  	pmksa = os_zalloc(sizeof(*pmksa));
  	if (pmksa) {
  		pmksa->free_cb = free_cb;
  		pmksa->ctx = ctx;
  		pmksa->sm = sm;
  	}
  
  	return pmksa;
  }
  
  #endif /* IEEE8021X_EAPOL */
  