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 "config.h"
  21 #include "l2_packet/l2_packet.h"
  22 #include "ieee802_1x.h"
  23 #include "eloop.h"
  24 #include "sta_flags.h"
  25 #include "sta_info.h"
  26 #include "common/wpa_common.h"
  27 #include "eapol_sm.h"
  28 #include "wpa.h"
  29 #include "preauth.h"
  30
  31 #ifndef ETH_P_PREAUTH
  32 #define ETH_P_PREAUTH 0x88C7 /* IEEE 802.11i pre-authentication */
  33 #endif /* ETH_P_PREAUTH */
  34
  35 static const int dot11RSNAConfigPMKLifetime = 43200;
  36
  37 struct rsn_preauth_interface {
  38         struct rsn_preauth_interface *next;
  39         struct hostapd_data *hapd;
  40         struct l2_packet_data *l2;
  41         char *ifname;
  42         int ifindex;
  43 };
  44
  45
  46 static void rsn_preauth_receive(void *ctx, const u8 *src_addr,
  47                                 const u8 *buf, size_t len)
  48 {
  49         struct rsn_preauth_interface *piface = ctx;
  50         struct hostapd_data *hapd = piface->hapd;
  51         struct ieee802_1x_hdr *hdr;
  52         struct sta_info *sta;
  53         struct l2_ethhdr *ethhdr;
  54
  55         wpa_printf(MSG_DEBUG, "RSN: receive pre-auth packet "
  56                    "from interface '%s'", piface->ifname);
  57         if (len < sizeof(*ethhdr) + sizeof(*hdr)) {
  58                 wpa_printf(MSG_DEBUG, "RSN: too short pre-auth packet "
  59                            "(len=%lu)", (unsigned long) len);
  60                 return;
  61         }
  62
  63         ethhdr = (struct l2_ethhdr *) buf;
  64         hdr = (struct ieee802_1x_hdr *) (ethhdr + 1);
  65
  66         if (os_memcmp(ethhdr->h_dest, hapd->own_addr, ETH_ALEN) != 0) {
  67                 wpa_printf(MSG_DEBUG, "RSN: pre-auth for foreign address "
  68                            MACSTR, MAC2STR(ethhdr->h_dest));
  69                 return;
  70         }
  71
  72         sta = ap_get_sta(hapd, ethhdr->h_source);
  73         if (sta && (sta->flags & WLAN_STA_ASSOC)) {
  74                 wpa_printf(MSG_DEBUG, "RSN: pre-auth for already association "
  75                            "STA " MACSTR, 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         wpa_printf(MSG_DEBUG, "RSN pre-auth interface '%s'", ifname);
 107
 108         piface = os_zalloc(sizeof(*piface));
 109         if (piface == NULL)
 110                 return -1;
 111         piface->hapd = hapd;
 112
 113         piface->ifname = os_strdup(ifname);
 114         if (piface->ifname == NULL) {
 115                 goto fail1;
 116         }
 117
 118         piface->l2 = l2_packet_init(piface->ifname, NULL, ETH_P_PREAUTH,
 119                                     rsn_preauth_receive, piface, 1);
 120         if (piface->l2 == NULL) {
 121                 wpa_printf(MSG_ERROR, "Failed to open register layer 2 access "
 122                            "to ETH_P_PREAUTH");
 123                 goto fail2;
 124         }
 125
 126         piface->next = hapd->preauth_iface;
 127         hapd->preauth_iface = piface;
 128         return 0;
 129
 130 fail2:
 131         os_free(piface->ifname);
 132 fail1:
 133         os_free(piface);
 134         return -1;
 135 }
 136
 137
 138 void rsn_preauth_iface_deinit(struct hostapd_data *hapd)
 139 {
 140         struct rsn_preauth_interface *piface, *prev;
 141
 142         piface = hapd->preauth_iface;
 143         hapd->preauth_iface = NULL;
 144         while (piface) {
 145                 prev = piface;
 146                 piface = piface->next;
 147                 l2_packet_deinit(prev->l2);
 148                 os_free(prev->ifname);
 149                 os_free(prev);
 150         }
 151 }
 152
 153
 154 int rsn_preauth_iface_init(struct hostapd_data *hapd)
 155 {
 156         char *tmp, *start, *end;
 157
 158         if (hapd->conf->rsn_preauth_interfaces == NULL)
 159                 return 0;
 160
 161         tmp = os_strdup(hapd->conf->rsn_preauth_interfaces);
 162         if (tmp == NULL)
 163                 return -1;
 164         start = tmp;
 165         for (;;) {
 166                 while (*start == ' ')
 167                         start++;
 168                 if (*start == '\0')
 169                         break;
 170                 end = os_strchr(start, ' ');
 171                 if (end)
 172                         *end = '\0';
 173
 174                 if (rsn_preauth_iface_add(hapd, start)) {
 175                         rsn_preauth_iface_deinit(hapd);
 176                         return -1;
 177                 }
 178
 179                 if (end)
 180                         start = end + 1;
 181                 else
 182                         break;
 183         }
 184         os_free(tmp);
 185         return 0;
 186 }
 187
 188
 189 static void rsn_preauth_finished_cb(void *eloop_ctx, void *timeout_ctx)
 190 {
 191         struct hostapd_data *hapd = eloop_ctx;
 192         struct sta_info *sta = timeout_ctx;
 193         wpa_printf(MSG_DEBUG, "RSN: Removing pre-authentication STA entry for "
 194                    MACSTR, MAC2STR(sta->addr));
 195         ap_free_sta(hapd, sta);
 196 }
 197
 198
 199 void rsn_preauth_finished(struct hostapd_data *hapd, struct sta_info *sta,
 200                           int success)
 201 {
 202         const u8 *key;
 203         size_t len;
 204         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 205                        HOSTAPD_LEVEL_INFO, "pre-authentication %s",
 206                        success ? "succeeded" : "failed");
 207
 208         key = ieee802_1x_get_key(sta->eapol_sm, &len);
 209         if (len > PMK_LEN)
 210                 len = PMK_LEN;
 211         if (success && key) {
 212                 if (wpa_auth_pmksa_add_preauth(hapd->wpa_auth, key, len,
 213                                                sta->addr,
 214                                                dot11RSNAConfigPMKLifetime,
 215                                                sta->eapol_sm) == 0) {
 216                         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 217                                        HOSTAPD_LEVEL_DEBUG,
 218                                        "added PMKSA cache entry (pre-auth)");
 219                 } else {
 220                         hostapd_logger(hapd, sta->addr, HOSTAPD_MODULE_WPA,
 221                                        HOSTAPD_LEVEL_DEBUG,
 222                                        "failed to add PMKSA cache entry "
 223                                        "(pre-auth)");
 224                 }
 225         }
 226
 227         /*
 228          * Finish STA entry removal from timeout in order to avoid freeing
 229          * STA data before the caller has finished processing.
 230          */
 231         eloop_register_timeout(0, 0, rsn_preauth_finished_cb, hapd, sta);
 232 }
 233
 234
 235 void rsn_preauth_send(struct hostapd_data *hapd, struct sta_info *sta,
 236                       u8 *buf, size_t len)
 237 {
 238         struct rsn_preauth_interface *piface;
 239         struct l2_ethhdr *ethhdr;
 240
 241         piface = hapd->preauth_iface;
 242         while (piface) {
 243                 if (piface == sta->preauth_iface)
 244                         break;
 245                 piface = piface->next;
 246         }
 247
 248         if (piface == NULL) {
 249                 wpa_printf(MSG_DEBUG, "RSN: Could not find pre-authentication "
 250                            "interface for " MACSTR, MAC2STR(sta->addr));
 251                 return;
 252         }
 253
 254         ethhdr = os_malloc(sizeof(*ethhdr) + len);
 255         if (ethhdr == NULL)
 256                 return;
 257
 258         os_memcpy(ethhdr->h_dest, sta->addr, ETH_ALEN);
 259         os_memcpy(ethhdr->h_source, hapd->own_addr, ETH_ALEN);
 260         ethhdr->h_proto = host_to_be16(ETH_P_PREAUTH);
 261         os_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                 wpa_printf(MSG_ERROR, "Failed to send preauth packet using "
 266                            "l2_packet_send\n");
 267         }
 268         os_free(ethhdr);
 269 }
 270
 271
 272 void rsn_preauth_free_station(struct hostapd_data *hapd, struct sta_info *sta)
 273 {
 274         eloop_cancel_timeout(rsn_preauth_finished_cb, hapd, sta);
 275 }
 276
 277 #endif /* CONFIG_RSN_PREAUTH */