contrib/hostapd-0.4.9/eap_sim_db.c

   1 /*
   2  * hostapd / EAP-SIM database/authenticator gateway
   3  * Copyright (c) 2005, Jouni Malinen <jkmaline@cc.hut.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 /* This is an example implementation of the EAP-SIM database/authentication
  16  * gateway interface that is expected to be replaced with an implementation of
  17  * SS7 gateway to GSM authentication center (HLR/AuC) or a local
  18  * implementation of SIM triplet generator.
  19  *
  20  * The example implementation here reads triplets from a text file in
  21  * IMSI:Kc:SRES:RAND format, IMSI in ASCII, other fields as hex strings. This
  22  * is used to simulate an HLR/AuC. As such, it is not very useful for real life
  23  * authentication, but it is useful both as an example implementation and for
  24  * EAP-SIM testing.
  25  */
  26
  27 #include <stdlib.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30
  31 #include "common.h"
  32 #include "eap_sim_common.h"
  33 #include "eap_sim_db.h"
  34
  35
  36 /* TODO: add an alternative callback based version of the interface. This is
  37  * needed to work better with the single threaded design of hostapd. For this,
  38  * the EAP data has to be stored somewhere and eap_sim_db is given a context
  39  * pointer for this and a callback function. The callback function will re-send
  40  * the EAP data through normal operations which will eventually end up calling
  41  * eap_sim_db_get_gsm_triplets() again for the same user. This time, eap_sim_db
  42  * should have the triplets available immediately. */
  43
  44
  45 struct eap_sim_db_data {
  46         char *fname;
  47 };
  48
  49 #define KC_LEN 8
  50 #define SRES_LEN 4
  51 #define RAND_LEN 16
  52
  53
  54 /* Initialize EAP-SIM database/authentication gateway interface.
  55  * Returns pointer to a private data structure. */
  56 void * eap_sim_db_init(const char *config)
  57 {
  58         struct eap_sim_db_data *data;
  59
  60         data = malloc(sizeof(*data));
  61         if (data == NULL) {
  62                 return NULL;
  63         }
  64
  65         memset(data, 0, sizeof(*data));
  66         data->fname = strdup(config);
  67         if (data->fname == NULL) {
  68                 free(data);
  69                 return NULL;
  70         }
  71
  72         return data;
  73 }
  74
  75 /* Deinitialize EAP-SIM database/authentication gateway interface.
  76  * priv is the pointer from eap_sim_db_init(). */
  77 void eap_sim_db_deinit(void *priv)
  78 {
  79         struct eap_sim_db_data *data = priv;
  80         free(data->fname);
  81         free(data);
  82 }
  83
  84
  85 /* Get GSM triplets for user name identity (identity_len bytes). In most cases,
  86  * the user name is '1' | IMSI, i.e., 1 followed by the IMSI in ASCII format.
  87  * The identity may also include NAI realm (@realm).
  88  * priv is the pointer from eap_sim_db_init().
  89  * Returns the number of triplets received (has to be less than or equal to
  90  * max_chal) or -1 on error (e.g., user not found). rand, kc, and sres are
  91  * pointers to data areas for the triplets. */
  92 int eap_sim_db_get_gsm_triplets(void *priv, const u8 *identity,
  93                                 size_t identity_len, int max_chal,
  94                                 u8 *rand, u8 *kc, u8 *sres)
  95 {
  96         struct eap_sim_db_data *data = priv;
  97         FILE *f;
  98         int count, i;
  99         char buf[80], *pos, *next;
 100
 101         f = fopen(data->fname, "r");
 102         if (f == NULL) {
 103                 wpa_printf(MSG_DEBUG, "EAP-SIM DB: could not open triplet "
 104                            "file '%s'", data->fname);
 105                 return -1;
 106         }
 107
 108         if (identity_len < 2 || identity[0] != '1') {
 109                 wpa_hexdump_ascii(MSG_DEBUG, "EAP-SIM DB: unexpected identity",
 110                                   identity, identity_len);
 111                 fclose(f);
 112                 return -1;
 113         }
 114         identity++;
 115         identity_len--;
 116         for (i = 0; i < identity_len; i++) {
 117                 if (identity[i] == '@') {
 118                         identity_len = i;
 119                         break;
 120                 }
 121         }
 122         wpa_hexdump_ascii(MSG_DEBUG, "EAP-SIM DB: get triplets for IMSI",
 123                           identity, identity_len);
 124
 125         count = 0;
 126         while (count < max_chal && fgets(buf, sizeof(buf), f)) {
 127                 /* Parse IMSI:Kc:SRES:RAND and match IMSI with identity. */
 128                 buf[sizeof(buf) - 1] = '\0';
 129                 pos = buf;
 130                 while (*pos != '\0' && *pos != '\n')
 131                         pos++;
 132                 if (*pos == '\n')
 133                         *pos = '\0';
 134                 if (pos - buf < 60 || pos[0] == '#')
 135                         continue;
 136
 137                 pos = strchr(buf, ':');
 138                 if (pos == NULL)
 139                         continue;
 140                 *pos++ = '\0';
 141                 if (strlen(buf) != identity_len ||
 142                     memcmp(buf, identity, identity_len) != 0)
 143                         continue;
 144
 145                 next = strchr(pos, ':');
 146                 if (next == NULL)
 147                         continue;
 148                 *next++ = '\0';
 149                 if (hexstr2bin(pos, &kc[count * KC_LEN], KC_LEN) < 0)
 150                         continue;
 151
 152                 pos = next;
 153                 next = strchr(pos, ':');
 154                 if (next == NULL)
 155                         continue;
 156                 *next++ = '\0';
 157                 if (hexstr2bin(pos, &sres[count * SRES_LEN], SRES_LEN) < 0)
 158                         continue;
 159
 160                 if (hexstr2bin(next, &rand[count * RAND_LEN], RAND_LEN) < 0)
 161                         continue;
 162
 163                 count++;
 164         }
 165
 166         fclose(f);
 167
 168         if (count == 0) {
 169                 wpa_printf(MSG_DEBUG, "EAP-SIM DB: no triplets found");
 170                 count = -1;
 171         }
 172
 173         return count;
 174 }
 175
 176
 177 /* Verify whether the given user identity (identity_len bytes) is known. In
 178  * most cases, the user name is '1' | IMSI, i.e., 1 followed by the IMSI in
 179  * ASCII format.
 180  * priv is the pointer from eap_sim_db_init().
 181  * Returns 0 if the user is found and GSM triplets would be available for it or
 182  * -1 on error (e.g., user not found or no triplets available). */
 183 int eap_sim_db_identity_known(void *priv, const u8 *identity,
 184                               size_t identity_len)
 185 {
 186         struct eap_sim_db_data *data = priv;
 187         FILE *f;
 188         char buf[80], *pos;
 189         int i;
 190
 191         if (identity_len < 1 || identity[0] != '1') {
 192                 return -1;
 193         }
 194
 195         f = fopen(data->fname, "r");
 196         if (f == NULL) {
 197                 wpa_printf(MSG_DEBUG, "EAP-SIM DB: could not open triplet "
 198                            "file '%s'", data->fname);
 199                 return -1;
 200         }
 201
 202         if (identity_len < 2 || identity[0] != '1') {
 203                 wpa_hexdump_ascii(MSG_DEBUG, "EAP-SIM DB: unexpected identity",
 204                                   identity, identity_len);
 205                 return -1;
 206         }
 207         identity++;
 208         identity_len--;
 209         for (i = 0; i < identity_len; i++) {
 210                 if (identity[i] == '@') {
 211                         identity_len = i;
 212                         break;
 213                 }
 214         }
 215
 216         while (fgets(buf, sizeof(buf), f)) {
 217                 /* Parse IMSI:Kc:SRES:RAND and match IMSI with identity. */
 218                 buf[sizeof(buf) - 1] = '\0';
 219                 pos = buf;
 220                 while (*pos != '\0' && *pos != '\n')
 221                         pos++;
 222                 if (*pos == '\n')
 223                         *pos = '\0';
 224                 if (pos - buf < 60 || pos[0] == '#')
 225                         continue;
 226
 227                 pos = strchr(buf, ':');
 228                 if (pos == NULL)
 229                         continue;
 230                 *pos++ = '\0';
 231                 if (strlen(buf) != identity_len ||
 232                     memcmp(buf, identity, identity_len) != 0)
 233                         continue;
 234
 235                 fclose(f);
 236                 return 0;
 237         }
 238
 239         /* IMSI not found */
 240
 241         fclose(f);
 242         return -1;
 243 }