pmksa_cache.c
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00001 /*
00002  * WPA Supplicant - RSN PMKSA cache
00003  * Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi>
00004  *
00005  * This program is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License version 2 as
00007  * published by the Free Software Foundation.
00008  *
00009  * Alternatively, this software may be distributed under the terms of BSD
00010  * license.
00011  *
00012  * See README and COPYING for more details.
00013  */
00014 
00015 #include "includes.h"
00016 
00017 #include "common.h"
00018 #include "eloop.h"
00019 #include "eapol_supp/eapol_supp_sm.h"
00020 #include "wpa.h"
00021 #include "wpa_i.h"
00022 #include "pmksa_cache.h"
00023 
00024 #if defined(IEEE8021X_EAPOL) && !defined(CONFIG_NO_WPA2)
00025 
00026 static const int pmksa_cache_max_entries = 32;
00027 
00028 struct rsn_pmksa_cache {
00029         struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */
00030         int pmksa_count; /* number of entries in PMKSA cache */
00031         struct wpa_sm *sm; /* TODO: get rid of this reference(?) */
00032 
00033         void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx,
00034                         int replace);
00035         void *ctx;
00036 };
00037 
00038 
00039 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
00040 
00041 
00042 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
00043 {
00044         os_free(entry);
00045 }
00046 
00047 
00048 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
00049                                    struct rsn_pmksa_cache_entry *entry,
00050                                    int replace)
00051 {
00052         pmksa->pmksa_count--;
00053         pmksa->free_cb(entry, pmksa->ctx, replace);
00054         _pmksa_cache_free_entry(entry);
00055 }
00056 
00057 
00058 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
00059 {
00060         struct rsn_pmksa_cache *pmksa = eloop_ctx;
00061         struct os_time now;
00062 
00063         os_get_time(&now);
00064         while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
00065                 struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
00066                 pmksa->pmksa = entry->next;
00067                 wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
00068                            MACSTR, MAC2STR(entry->aa));
00069                 pmksa_cache_free_entry(pmksa, entry, 0);
00070         }
00071 
00072         pmksa_cache_set_expiration(pmksa);
00073 }
00074 
00075 
00076 static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
00077 {
00078         struct rsn_pmksa_cache *pmksa = eloop_ctx;
00079         pmksa->sm->cur_pmksa = NULL;
00080         eapol_sm_request_reauth(pmksa->sm->eapol);
00081 }
00082 
00083 
00084 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
00085 {
00086         int sec;
00087         struct rsn_pmksa_cache_entry *entry;
00088         struct os_time now;
00089 
00090         eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
00091         eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
00092         if (pmksa->pmksa == NULL)
00093                 return;
00094         os_get_time(&now);
00095         sec = pmksa->pmksa->expiration - now.sec;
00096         if (sec < 0)
00097                 sec = 0;
00098         eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
00099 
00100         entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
00101                 pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL);
00102         if (entry) {
00103                 sec = pmksa->pmksa->reauth_time - now.sec;
00104                 if (sec < 0)
00105                         sec = 0;
00106                 eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
00107                                        NULL);
00108         }
00109 }
00110 
00111 
00128 struct rsn_pmksa_cache_entry *
00129 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
00130                 const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
00131 {
00132         struct rsn_pmksa_cache_entry *entry, *pos, *prev;
00133         struct os_time now;
00134 
00135         if (pmk_len > PMK_LEN)
00136                 return NULL;
00137 
00138         entry = os_zalloc(sizeof(*entry));
00139         if (entry == NULL)
00140                 return NULL;
00141         os_memcpy(entry->pmk, pmk, pmk_len);
00142         entry->pmk_len = pmk_len;
00143         rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
00144                   wpa_key_mgmt_sha256(akmp));
00145         os_get_time(&now);
00146         entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
00147         entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
00148                 pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
00149         entry->akmp = akmp;
00150         os_memcpy(entry->aa, aa, ETH_ALEN);
00151         entry->network_ctx = network_ctx;
00152 
00153         /* Replace an old entry for the same Authenticator (if found) with the
00154          * new entry */
00155         pos = pmksa->pmksa;
00156         prev = NULL;
00157         while (pos) {
00158                 if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
00159                         if (pos->pmk_len == pmk_len &&
00160                             os_memcmp(pos->pmk, pmk, pmk_len) == 0 &&
00161                             os_memcmp(pos->pmkid, entry->pmkid, PMKID_LEN) ==
00162                             0) {
00163                                 wpa_printf(MSG_DEBUG, "WPA: reusing previous "
00164                                            "PMKSA entry");
00165                                 os_free(entry);
00166                                 return pos;
00167                         }
00168                         if (prev == NULL)
00169                                 pmksa->pmksa = pos->next;
00170                         else
00171                                 prev->next = pos->next;
00172                         if (pos == pmksa->sm->cur_pmksa) {
00173                                 /* We are about to replace the current PMKSA
00174                                  * cache entry. This happens when the PMKSA
00175                                  * caching attempt fails, so we don't want to
00176                                  * force pmksa_cache_free_entry() to disconnect
00177                                  * at this point. Let's just make sure the old
00178                                  * PMKSA cache entry will not be used in the
00179                                  * future.
00180                                  */
00181                                 wpa_printf(MSG_DEBUG, "RSN: replacing current "
00182                                            "PMKSA entry");
00183                                 pmksa->sm->cur_pmksa = NULL;
00184                         }
00185                         wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
00186                                    "the current AP");
00187                         pmksa_cache_free_entry(pmksa, pos, 1);
00188                         break;
00189                 }
00190                 prev = pos;
00191                 pos = pos->next;
00192         }
00193 
00194         if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
00195                 /* Remove the oldest entry to make room for the new entry */
00196                 pos = pmksa->pmksa;
00197                 pmksa->pmksa = pos->next;
00198                 wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
00199                            "entry (for " MACSTR ") to make room for new one",
00200                            MAC2STR(pos->aa));
00201                 wpa_sm_remove_pmkid(pmksa->sm, pos->aa, pos->pmkid);
00202                 pmksa_cache_free_entry(pmksa, pos, 0);
00203         }
00204 
00205         /* Add the new entry; order by expiration time */
00206         pos = pmksa->pmksa;
00207         prev = NULL;
00208         while (pos) {
00209                 if (pos->expiration > entry->expiration)
00210                         break;
00211                 prev = pos;
00212                 pos = pos->next;
00213         }
00214         if (prev == NULL) {
00215                 entry->next = pmksa->pmksa;
00216                 pmksa->pmksa = entry;
00217                 pmksa_cache_set_expiration(pmksa);
00218         } else {
00219                 entry->next = prev->next;
00220                 prev->next = entry;
00221         }
00222         pmksa->pmksa_count++;
00223         wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
00224                    MAC2STR(entry->aa));
00225         wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);
00226 
00227         return entry;
00228 }
00229 
00230 
00235 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
00236 {
00237         struct rsn_pmksa_cache_entry *entry, *prev;
00238 
00239         if (pmksa == NULL)
00240                 return;
00241 
00242         entry = pmksa->pmksa;
00243         pmksa->pmksa = NULL;
00244         while (entry) {
00245                 prev = entry;
00246                 entry = entry->next;
00247                 os_free(prev);
00248         }
00249         pmksa_cache_set_expiration(pmksa);
00250         os_free(pmksa);
00251 }
00252 
00253 
00261 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
00262                                                const u8 *aa, const u8 *pmkid)
00263 {
00264         struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
00265         while (entry) {
00266                 if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
00267                     (pmkid == NULL ||
00268                      os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
00269                         return entry;
00270                 entry = entry->next;
00271         }
00272         return NULL;
00273 }
00274 
00275 
00282 void pmksa_cache_notify_reconfig(struct rsn_pmksa_cache *pmksa)
00283 {
00284         struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
00285         while (entry) {
00286                 entry->network_ctx = NULL;
00287                 entry = entry->next;
00288         }
00289 }
00290 
00291 
00292 static struct rsn_pmksa_cache_entry *
00293 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
00294                         const struct rsn_pmksa_cache_entry *old_entry,
00295                         const u8 *aa)
00296 {
00297         struct rsn_pmksa_cache_entry *new_entry;
00298 
00299         new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
00300                                     aa, pmksa->sm->own_addr,
00301                                     old_entry->network_ctx, old_entry->akmp);
00302         if (new_entry == NULL)
00303                 return NULL;
00304 
00305         /* TODO: reorder entries based on expiration time? */
00306         new_entry->expiration = old_entry->expiration;
00307         new_entry->opportunistic = 1;
00308 
00309         return new_entry;
00310 }
00311 
00312 
00324 struct rsn_pmksa_cache_entry *
00325 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
00326                               const u8 *aa)
00327 {
00328         struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
00329 
00330         if (network_ctx == NULL)
00331                 return NULL;
00332         while (entry) {
00333                 if (entry->network_ctx == network_ctx) {
00334                         entry = pmksa_cache_clone_entry(pmksa, entry, aa);
00335                         if (entry) {
00336                                 wpa_printf(MSG_DEBUG, "RSN: added "
00337                                            "opportunistic PMKSA cache entry "
00338                                            "for " MACSTR, MAC2STR(aa));
00339                         }
00340                         return entry;
00341                 }
00342                 entry = entry->next;
00343         }
00344         return NULL;
00345 }
00346 
00347 
00353 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
00354 {
00355         if (sm == NULL)
00356                 return NULL;
00357         return sm->cur_pmksa;
00358 }
00359 
00360 
00365 void pmksa_cache_clear_current(struct wpa_sm *sm)
00366 {
00367         if (sm == NULL)
00368                 return;
00369         sm->cur_pmksa = NULL;
00370 }
00371 
00372 
00382 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
00383                             const u8 *bssid, void *network_ctx,
00384                             int try_opportunistic)
00385 {
00386         struct rsn_pmksa_cache *pmksa = sm->pmksa;
00387         sm->cur_pmksa = NULL;
00388         if (pmkid)
00389                 sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid);
00390         if (sm->cur_pmksa == NULL && bssid)
00391                 sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL);
00392         if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
00393                 sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
00394                                                               network_ctx,
00395                                                               bssid);
00396         if (sm->cur_pmksa) {
00397                 wpa_hexdump(MSG_DEBUG, "RSN: PMKID",
00398                             sm->cur_pmksa->pmkid, PMKID_LEN);
00399                 return 0;
00400         }
00401         return -1;
00402 }
00403 
00404 
00415 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
00416 {
00417         int i, ret;
00418         char *pos = buf;
00419         struct rsn_pmksa_cache_entry *entry;
00420         struct os_time now;
00421 
00422         os_get_time(&now);
00423         ret = os_snprintf(pos, buf + len - pos,
00424                           "Index / AA / PMKID / expiration (in seconds) / "
00425                           "opportunistic\n");
00426         if (ret < 0 || ret >= buf + len - pos)
00427                 return pos - buf;
00428         pos += ret;
00429         i = 0;
00430         entry = pmksa->pmksa;
00431         while (entry) {
00432                 i++;
00433                 ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
00434                                   i, MAC2STR(entry->aa));
00435                 if (ret < 0 || ret >= buf + len - pos)
00436                         return pos - buf;
00437                 pos += ret;
00438                 pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
00439                                         PMKID_LEN);
00440                 ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
00441                                   (int) (entry->expiration - now.sec),
00442                                   entry->opportunistic);
00443                 if (ret < 0 || ret >= buf + len - pos)
00444                         return pos - buf;
00445                 pos += ret;
00446                 entry = entry->next;
00447         }
00448         return pos - buf;
00449 }
00450 
00451 
00459 struct rsn_pmksa_cache *
00460 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
00461                                  void *ctx, int replace),
00462                  void *ctx, struct wpa_sm *sm)
00463 {
00464         struct rsn_pmksa_cache *pmksa;
00465 
00466         pmksa = os_zalloc(sizeof(*pmksa));
00467         if (pmksa) {
00468                 pmksa->free_cb = free_cb;
00469                 pmksa->ctx = ctx;
00470                 pmksa->sm = sm;
00471         }
00472 
00473         return pmksa;
00474 }
00475 
00476 #endif /* IEEE8021X_EAPOL and !CONFIG_NO_WPA2 */


wpa_supplicant_node
Author(s): Package maintained by Blaise Gassend
autogenerated on Thu Jan 2 2014 11:25:14