contrib/hostapd/preauth.c

   1 /*
   2  * hostapd - Authenticator for IEEE 802.11i RSN pre-authentication
   3  * Copyright (c) 2004-2006, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "includes.h"
  16
  17 #ifdef CONFIG_RSN_PREAUTH
  18
  19 #include "hostapd.h"
  20 #include "l2_packet.h"
  21 #include "ieee802_1x.h"
  22 #include "eloop.h"
  23 #include "sta_info.h"
  24 #include "wpa_common.h"
  25 #include "eapol_sm.h"
  26 #include "wpa.h"
  27 #include "preauth.h"
  28
  29 #ifndef ETH_P_PREAUTH
  30 #define ETH_P_PREAUTH 0x88C7 /* IEEE 802.11i pre-authentication */
  31 #endif /* ETH_P_PREAUTH */
  32
  33 static const int dot11RSNAConfigPMKLifetime = 43200;
  34
  35 struct rsn_preauth_interface {
  36         struct rsn_preauth_interface *next;
  37         struct hostapd_data *hapd;
  38         struct l2_packet_data *l2;
  39         char *ifname;
  40         int ifindex;
  41 };
  42
  43
  44 static void rsn_preauth_receive(void *ctx, const u8 *src_addr,
  45                                 const u8 *buf, size_t len)
  46 {
  47         struct rsn_preauth_interface *piface = ctx;
  48         struct hostapd_data *hapd = piface->hapd;
  49         struct ieee802_1x_hdr *hdr;
  50         struct sta_info *sta;
  51         struct l2_ethhdr *ethhdr;
  52
  53         HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL, "RSN: receive pre-auth packet "
  54                       "from interface '%s'\n", piface->ifname);
  55         if (len < sizeof(*ethhdr) + sizeof(*hdr)) {
  56                 HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL, "RSN: too short pre-auth "
  57                               "packet (len=%lu)\n", (unsigned long) len);
  58                 return;
  59         }
  60
  61         ethhdr = (struct l2_ethhdr *) buf;
  62         hdr = (struct ieee802_1x_hdr *) (ethhdr + 1);
  63
  64         if (memcmp(ethhdr->h_dest, hapd->own_addr, ETH_ALEN) != 0) {
  65                 HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL, "RSN: pre-auth for "
  66                               "foreign address " MACSTR "\n",
  67                               MAC2STR(ethhdr->h_dest));
  68                 return;
  69         }
  70
  71         sta = ap_get_sta(hapd, ethhdr->h_source);
  72         if (sta && (sta->flags & WLAN_STA_ASSOC)) {
  73                 HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL, "RSN: pre-auth for "
  74                               "already association STA " MACSTR "\n",
  75                               MAC2STR(sta->addr));
  76                 return;
  77         }
  78         if (!sta && hdr->type == IEEE802_1X_TYPE_EAPOL_START) {
  79                 sta = ap_sta_add(hapd, ethhdr->h_source);
  80                 if (sta == NULL)
  81                         return;
  82                 sta->flags = WLAN_STA_PREAUTH;
  83
  84                 ieee802_1x_new_station(hapd, sta);
  85                 if (sta->eapol_sm == NULL) {
  86                         ap_free_sta(hapd, sta);
  87                         sta = NULL;
  88                 } else {
  89                         sta->eapol_sm->radius_identifier = -1;
  90                         sta->eapol_sm->portValid = TRUE;
  91                         sta->eapol_sm->flags |= EAPOL_SM_PREAUTH;
  92                 }
  93         }
  94         if (sta == NULL)
  95                 return;
  96         sta->preauth_iface = piface;
  97         ieee802_1x_receive(hapd, ethhdr->h_source, (u8 *) (ethhdr + 1),
  98                            len - sizeof(*ethhdr));
  99 }
 100
 101
 102 static int rsn_preauth_iface_add(struct hostapd_data *hapd, const char *ifname)
 103 {
 104         struct rsn_preauth_interface *piface;
 105
 106         HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL, "RSN pre-auth interface '%s'\n",
 107                       ifname);
 108
 109         piface = wpa_zalloc(sizeof(*piface));
 110         if (piface == NULL)
 111                 return -1;
 112         piface->hapd = hapd;
 113
 114         piface->ifname = strdup(ifname);
 115         if (piface->ifname == NULL) {
 116                 goto fail1;
 117         }
 118
 119         piface->l2 = l2_packet_init(piface->ifname, NULL, ETH_P_PREAUTH,
 120                                     rsn_preauth_receive, piface, 1);
 121         if (piface->l2 == NULL) {
 122                 printf("Failed to open register layer 2 access to "
 123                        "ETH_P_PREAUTH\n");
 124                 goto fail2;
 125         }
 126
 127         piface->next = hapd->preauth_iface;
 128         hapd->preauth_iface = piface;
 129         return 0;
 130
 131 fail2:
 132         free(piface->ifname);
 133 fail1:
 134         free(piface);
 135         return -1;
 136 }
 137
 138
 139 void rsn_preauth_iface_deinit(struct hostapd_data *hapd)
 140 {
 141         struct rsn_preauth_interface *piface, *prev;
 142
 143         piface = hapd->preauth_iface;
 144         hapd->preauth_iface = NULL;
 145         while (piface) {
 146                 prev = piface;
 147                 piface = piface->next;
 148                 l2_packet_deinit(prev->l2);
 149                 free(prev->ifname);
 150                 free(prev);
 151         }
 152 }
 153
 154
 155 int rsn_preauth_iface_init(struct hostapd_data *hapd)
 156 {
 157         char *tmp, *start, *end;
 158
 159         if (hapd->conf->rsn_preauth_interfaces == NULL)
 160                 return 0;
 161
 162         tmp = strdup(hapd->conf->rsn_preauth_interfaces);
 163         if (tmp == NULL)
 164                 return -1;
 165         start = tmp;
 166         for (;;) {
 167                 while (*start == ' ')
 168                         start++;
 169                 if (*start == '\0')
 170                         break;
 171                 end = strchr(start, ' ');
 172                 if (end)
 173                         *end = '\0';
 174
 175                 if (rsn_preauth_iface_add(hapd, start)) {
 176                         rsn_preauth_iface_deinit(hapd);
 177                         return -1;
 178                 }
 179
 180                 if (end)
 181                         start = end + 1;
 182                 else
 183                         break;
 184         }
 185         free(tmp);
 186         return 0;
 187 }
 188
 189
 190 static void rsn_preauth_finished_cb(void *eloop_ctx, void *timeout_ctx)
 191 {
 192         struct hostapd_data *hapd = eloop_ctx;
 193         struct sta_info *sta = timeout_ctx;
 194         wpa_printf(MSG_DEBUG, "RSN: Removing pre-authentication STA entry for "
 195                    MACSTR, MAC2STR(sta->addr));
 196         ap_free_sta(hapd, sta);
 197 }
 198
 199
 200 void rsn_preauth_finished(struct hostapd_data *hapd, struct sta_info *sta,
 201                           int success)
 202 {
 203         u8 *key;
 204         size_t len;
 205         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 206                        HOSTAPD_LEVEL_INFO, "pre-authentication %s",
 207                        success ? "succeeded" : "failed");
 208
 209         key = ieee802_1x_get_key_crypt(sta->eapol_sm, &len);
 210         if (success && key) {
 211                 if (wpa_auth_pmksa_add_preauth(hapd->wpa_auth, key, len,
 212                                                sta->addr,
 213                                                dot11RSNAConfigPMKLifetime,
 214                                                sta->eapol_sm) == 0) {
 215                         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 216                                        HOSTAPD_LEVEL_DEBUG,
 217                                        "added PMKSA cache entry (pre-auth)");
 218                 } else {
 219                         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 220                                        HOSTAPD_LEVEL_DEBUG,
 221                                        "failed to add PMKSA cache entry "
 222                                        "(pre-auth)");
 223                 }
 224         }
 225
 226         /*
 227          * Finish STA entry removal from timeout in order to avoid freeing
 228          * STA data before the caller has finished processing.
 229          */
 230         eloop_register_timeout(0, 0, rsn_preauth_finished_cb, hapd, sta);
 231 }
 232
 233
 234 void rsn_preauth_send(struct hostapd_data *hapd, struct sta_info *sta,
 235                       u8 *buf, size_t len)
 236 {
 237         struct rsn_preauth_interface *piface;
 238         struct l2_ethhdr *ethhdr;
 239
 240         piface = hapd->preauth_iface;
 241         while (piface) {
 242                 if (piface == sta->preauth_iface)
 243                         break;
 244                 piface = piface->next;
 245         }
 246
 247         if (piface == NULL) {
 248                 HOSTAPD_DEBUG(HOSTAPD_DEBUG_MINIMAL, "RSN: Could not find "
 249                               "pre-authentication interface for " MACSTR "\n",
 250                               MAC2STR(sta->addr));
 251                 return;
 252         }
 253
 254         ethhdr = malloc(sizeof(*ethhdr) + len);
 255         if (ethhdr == NULL)
 256                 return;
 257
 258         memcpy(ethhdr->h_dest, sta->addr, ETH_ALEN);
 259         memcpy(ethhdr->h_source, hapd->own_addr, ETH_ALEN);
 260         ethhdr->h_proto = htons(ETH_P_PREAUTH);
 261         memcpy(ethhdr + 1, buf, len);
 262
 263         if (l2_packet_send(piface->l2, sta->addr, ETH_P_PREAUTH, (u8 *) ethhdr,
 264                            sizeof(*ethhdr) + len) < 0) {
 265                 printf("Failed to send preauth packet using l2_packet_send\n");
 266         }
 267         free(ethhdr);
 268 }
 269
 270
 271 void rsn_preauth_free_station(struct hostapd_data *hapd, struct sta_info *sta)
 272 {
 273         eloop_cancel_timeout(rsn_preauth_finished_cb, hapd, sta);
 274 }
 275
 276 #endif /* CONFIG_RSN_PREAUTH */