dist/wpa/hostapd/preauth.c

   1 /*
   2  * hostapd - Authenticator for IEEE 802.11i RSN pre-authentication
   3  * Copyright (c) 2004-2007, 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/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         wpa_printf(MSG_DEBUG, "RSN: receive pre-auth packet "
  54                    "from interface '%s'", piface->ifname);
  55         if (len < sizeof(*ethhdr) + sizeof(*hdr)) {
  56                 wpa_printf(MSG_DEBUG, "RSN: too short pre-auth packet "
  57                            "(len=%lu)", (unsigned long) len);
  58                 return;
  59         }
  60
  61         ethhdr = (struct l2_ethhdr *) buf;
  62         hdr = (struct ieee802_1x_hdr *) (ethhdr + 1);
  63
  64         if (os_memcmp(ethhdr->h_dest, hapd->own_addr, ETH_ALEN) != 0) {
  65                 wpa_printf(MSG_DEBUG, "RSN: pre-auth for foreign address "
  66                            MACSTR, MAC2STR(ethhdr->h_dest));
  67                 return;
  68         }
  69
  70         sta = ap_get_sta(hapd, ethhdr->h_source);
  71         if (sta && (sta->flags & WLAN_STA_ASSOC)) {
  72                 wpa_printf(MSG_DEBUG, "RSN: pre-auth for already association "
  73                            "STA " MACSTR, MAC2STR(sta->addr));
  74                 return;
  75         }
  76         if (!sta && hdr->type == IEEE802_1X_TYPE_EAPOL_START) {
  77                 sta = ap_sta_add(hapd, ethhdr->h_source);
  78                 if (sta == NULL)
  79                         return;
  80                 sta->flags = WLAN_STA_PREAUTH;
  81
  82                 ieee802_1x_new_station(hapd, sta);
  83                 if (sta->eapol_sm == NULL) {
  84                         ap_free_sta(hapd, sta);
  85                         sta = NULL;
  86                 } else {
  87                         sta->eapol_sm->radius_identifier = -1;
  88                         sta->eapol_sm->portValid = TRUE;
  89                         sta->eapol_sm->flags |= EAPOL_SM_PREAUTH;
  90                 }
  91         }
  92         if (sta == NULL)
  93                 return;
  94         sta->preauth_iface = piface;
  95         ieee802_1x_receive(hapd, ethhdr->h_source, (u8 *) (ethhdr + 1),
  96                            len - sizeof(*ethhdr));
  97 }
  98
  99
 100 static int rsn_preauth_iface_add(struct hostapd_data *hapd, const char *ifname)
 101 {
 102         struct rsn_preauth_interface *piface;
 103
 104         wpa_printf(MSG_DEBUG, "RSN pre-auth interface '%s'", ifname);
 105
 106         piface = os_zalloc(sizeof(*piface));
 107         if (piface == NULL)
 108                 return -1;
 109         piface->hapd = hapd;
 110
 111         piface->ifname = os_strdup(ifname);
 112         if (piface->ifname == NULL) {
 113                 goto fail1;
 114         }
 115
 116         piface->l2 = l2_packet_init(piface->ifname, NULL, ETH_P_PREAUTH,
 117                                     rsn_preauth_receive, piface, 1);
 118         if (piface->l2 == NULL) {
 119                 wpa_printf(MSG_ERROR, "Failed to open register layer 2 access "
 120                            "to ETH_P_PREAUTH");
 121                 goto fail2;
 122         }
 123
 124         piface->next = hapd->preauth_iface;
 125         hapd->preauth_iface = piface;
 126         return 0;
 127
 128 fail2:
 129         os_free(piface->ifname);
 130 fail1:
 131         os_free(piface);
 132         return -1;
 133 }
 134
 135
 136 void rsn_preauth_iface_deinit(struct hostapd_data *hapd)
 137 {
 138         struct rsn_preauth_interface *piface, *prev;
 139
 140         piface = hapd->preauth_iface;
 141         hapd->preauth_iface = NULL;
 142         while (piface) {
 143                 prev = piface;
 144                 piface = piface->next;
 145                 l2_packet_deinit(prev->l2);
 146                 os_free(prev->ifname);
 147                 os_free(prev);
 148         }
 149 }
 150
 151
 152 int rsn_preauth_iface_init(struct hostapd_data *hapd)
 153 {
 154         char *tmp, *start, *end;
 155
 156         if (hapd->conf->rsn_preauth_interfaces == NULL)
 157                 return 0;
 158
 159         tmp = os_strdup(hapd->conf->rsn_preauth_interfaces);
 160         if (tmp == NULL)
 161                 return -1;
 162         start = tmp;
 163         for (;;) {
 164                 while (*start == ' ')
 165                         start++;
 166                 if (*start == '\0')
 167                         break;
 168                 end = os_strchr(start, ' ');
 169                 if (end)
 170                         *end = '\0';
 171
 172                 if (rsn_preauth_iface_add(hapd, start)) {
 173                         rsn_preauth_iface_deinit(hapd);
 174                         return -1;
 175                 }
 176
 177                 if (end)
 178                         start = end + 1;
 179                 else
 180                         break;
 181         }
 182         os_free(tmp);
 183         return 0;
 184 }
 185
 186
 187 static void rsn_preauth_finished_cb(void *eloop_ctx, void *timeout_ctx)
 188 {
 189         struct hostapd_data *hapd = eloop_ctx;
 190         struct sta_info *sta = timeout_ctx;
 191         wpa_printf(MSG_DEBUG, "RSN: Removing pre-authentication STA entry for "
 192                    MACSTR, MAC2STR(sta->addr));
 193         ap_free_sta(hapd, sta);
 194 }
 195
 196
 197 void rsn_preauth_finished(struct hostapd_data *hapd, struct sta_info *sta,
 198                           int success)
 199 {
 200         const u8 *key;
 201         size_t len;
 202         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 203                        HOSTAPD_LEVEL_INFO, "pre-authentication %s",
 204                        success ? "succeeded" : "failed");
 205
 206         key = ieee802_1x_get_key(sta->eapol_sm, &len);
 207         if (len > PMK_LEN)
 208                 len = PMK_LEN;
 209         if (success && key) {
 210                 if (wpa_auth_pmksa_add_preauth(hapd->wpa_auth, key, len,
 211                                                sta->addr,
 212                                                dot11RSNAConfigPMKLifetime,
 213                                                sta->eapol_sm) == 0) {
 214                         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 215                                        HOSTAPD_LEVEL_DEBUG,
 216                                        "added PMKSA cache entry (pre-auth)");
 217                 } else {
 218                         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 219                                        HOSTAPD_LEVEL_DEBUG,
 220                                        "failed to add PMKSA cache entry "
 221                                        "(pre-auth)");
 222                 }
 223         }
 224
 225         /*
 226          * Finish STA entry removal from timeout in order to avoid freeing
 227          * STA data before the caller has finished processing.
 228          */
 229         eloop_register_timeout(0, 0, rsn_preauth_finished_cb, hapd, sta);
 230 }
 231
 232
 233 void rsn_preauth_send(struct hostapd_data *hapd, struct sta_info *sta,
 234                       u8 *buf, size_t len)
 235 {
 236         struct rsn_preauth_interface *piface;
 237         struct l2_ethhdr *ethhdr;
 238
 239         piface = hapd->preauth_iface;
 240         while (piface) {
 241                 if (piface == sta->preauth_iface)
 242                         break;
 243                 piface = piface->next;
 244         }
 245
 246         if (piface == NULL) {
 247                 wpa_printf(MSG_DEBUG, "RSN: Could not find pre-authentication "
 248                            "interface for " MACSTR, MAC2STR(sta->addr));
 249                 return;
 250         }
 251
 252         ethhdr = os_malloc(sizeof(*ethhdr) + len);
 253         if (ethhdr == NULL)
 254                 return;
 255
 256         os_memcpy(ethhdr->h_dest, sta->addr, ETH_ALEN);
 257         os_memcpy(ethhdr->h_source, hapd->own_addr, ETH_ALEN);
 258         ethhdr->h_proto = htons(ETH_P_PREAUTH);
 259         os_memcpy(ethhdr + 1, buf, len);
 260
 261         if (l2_packet_send(piface->l2, sta->addr, ETH_P_PREAUTH, (u8 *) ethhdr,
 262                            sizeof(*ethhdr) + len) < 0) {
 263                 wpa_printf(MSG_ERROR, "Failed to send preauth packet using "
 264                            "l2_packet_send\n");
 265         }
 266         os_free(ethhdr);
 267 }
 268
 269
 270 void rsn_preauth_free_station(struct hostapd_data *hapd, struct sta_info *sta)
 271 {
 272         eloop_cancel_timeout(rsn_preauth_finished_cb, hapd, sta);
 273 }
 274
 275 #endif /* CONFIG_RSN_PREAUTH */