contrib/hostapd-0.5.8/eap_tls_common.c

   1 /*
   2  * hostapd / EAP-TLS/PEAP/TTLS common functions
   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 #include "hostapd.h"
  18 #include "common.h"
  19 #include "eap_i.h"
  20 #include "eap_tls_common.h"
  21 #include "sha1.h"
  22 #include "tls.h"
  23
  24
  25 int eap_tls_ssl_init(struct eap_sm *sm, struct eap_ssl_data *data,
  26                      int verify_peer)
  27 {
  28         data->eap = sm;
  29         data->phase2 = sm->init_phase2;
  30
  31         data->conn = tls_connection_init(sm->ssl_ctx);
  32         if (data->conn == NULL) {
  33                 wpa_printf(MSG_INFO, "SSL: Failed to initialize new TLS "
  34                            "connection");
  35                 return -1;
  36         }
  37
  38         if (tls_connection_set_verify(sm->ssl_ctx, data->conn, verify_peer)) {
  39                 wpa_printf(MSG_INFO, "SSL: Failed to configure verification "
  40                            "of TLS peer certificate");
  41                 tls_connection_deinit(sm->ssl_ctx, data->conn);
  42                 data->conn = NULL;
  43                 return -1;
  44         }
  45
  46         /* TODO: make this configurable */
  47         data->tls_out_limit = 1398;
  48         if (data->phase2) {
  49                 /* Limit the fragment size in the inner TLS authentication
  50                  * since the outer authentication with EAP-PEAP does not yet
  51                  * support fragmentation */
  52                 if (data->tls_out_limit > 100)
  53                         data->tls_out_limit -= 100;
  54         }
  55         return 0;
  56 }
  57
  58
  59 void eap_tls_ssl_deinit(struct eap_sm *sm, struct eap_ssl_data *data)
  60 {
  61         tls_connection_deinit(sm->ssl_ctx, data->conn);
  62         free(data->tls_in);
  63         free(data->tls_out);
  64 }
  65
  66
  67 u8 * eap_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data,
  68                         char *label, size_t len)
  69 {
  70         struct tls_keys keys;
  71         u8 *rnd = NULL, *out;
  72
  73         out = malloc(len);
  74         if (out == NULL)
  75                 return NULL;
  76
  77         if (tls_connection_prf(sm->ssl_ctx, data->conn, label, 0, out, len) ==
  78             0)
  79                 return out;
  80
  81         if (tls_connection_get_keys(sm->ssl_ctx, data->conn, &keys))
  82                 goto fail;
  83
  84         if (keys.client_random == NULL || keys.server_random == NULL ||
  85             keys.master_key == NULL)
  86                 goto fail;
  87
  88         rnd = malloc(keys.client_random_len + keys.server_random_len);
  89         if (rnd == NULL)
  90                 goto fail;
  91         memcpy(rnd, keys.client_random, keys.client_random_len);
  92         memcpy(rnd + keys.client_random_len, keys.server_random,
  93                keys.server_random_len);
  94
  95         if (tls_prf(keys.master_key, keys.master_key_len,
  96                     label, rnd, keys.client_random_len +
  97                     keys.server_random_len, out, len))
  98                 goto fail;
  99
 100         free(rnd);
 101         return out;
 102
 103 fail:
 104         free(out);
 105         free(rnd);
 106         return NULL;
 107 }
 108
 109
 110 int eap_tls_data_reassemble(struct eap_sm *sm, struct eap_ssl_data *data,
 111                             u8 **in_data, size_t *in_len)
 112 {
 113         u8 *buf;
 114
 115         if (data->tls_in_left > *in_len || data->tls_in) {
 116                 if (data->tls_in_len + *in_len > 65536) {
 117                         /* Limit length to avoid rogue peers from causing large
 118                          * memory allocations. */
 119                         free(data->tls_in);
 120                         data->tls_in = NULL;
 121                         data->tls_in_len = 0;
 122                         wpa_printf(MSG_INFO, "SSL: Too long TLS fragment (size"
 123                                    " over 64 kB)");
 124                         return -1;
 125                 }
 126                 buf = realloc(data->tls_in, data->tls_in_len + *in_len);
 127                 if (buf == NULL) {
 128                         free(data->tls_in);
 129                         data->tls_in = NULL;
 130                         data->tls_in_len = 0;
 131                         wpa_printf(MSG_INFO, "SSL: Could not allocate memory "
 132                                    "for TLS data");
 133                         return -1;
 134                 }
 135                 memcpy(buf + data->tls_in_len, *in_data, *in_len);
 136                 data->tls_in = buf;
 137                 data->tls_in_len += *in_len;
 138                 if (*in_len > data->tls_in_left) {
 139                         wpa_printf(MSG_INFO, "SSL: more data than TLS message "
 140                                    "length indicated");
 141                         data->tls_in_left = 0;
 142                         return -1;
 143                 }
 144                 data->tls_in_left -= *in_len;
 145                 if (data->tls_in_left > 0) {
 146                         wpa_printf(MSG_DEBUG, "SSL: Need %lu bytes more input "
 147                                    "data", (unsigned long) data->tls_in_left);
 148                         return 1;
 149                 }
 150
 151                 *in_data = data->tls_in;
 152                 *in_len = data->tls_in_len;
 153         } else
 154                 data->tls_in_left = 0;
 155
 156         return 0;
 157 }
 158
 159
 160 int eap_tls_process_helper(struct eap_sm *sm, struct eap_ssl_data *data,
 161                            u8 *in_data, size_t in_len)
 162 {
 163         WPA_ASSERT(data->tls_out_len == 0 || in_len == 0);
 164
 165         if (data->tls_out_len == 0) {
 166                 /* No more data to send out - expect to receive more data from
 167                  * the peer. */
 168                 int res = eap_tls_data_reassemble(sm, data, &in_data, &in_len);
 169                 if (res < 0 || res == 1) {
 170                         wpa_printf(MSG_DEBUG, "SSL: data reassembly failed");
 171                         return res;
 172                 }
 173                 /* Full TLS message reassembled - continue handshake processing
 174                  */
 175                 if (data->tls_out) {
 176                         /* This should not happen.. */
 177                         wpa_printf(MSG_INFO, "SSL: eap_tls_process_helper - "
 178                                    "pending tls_out data even though "
 179                                    "tls_out_len = 0");
 180                         free(data->tls_out);
 181                         WPA_ASSERT(data->tls_out == NULL);
 182                 }
 183                 data->tls_out = tls_connection_server_handshake(
 184                         sm->ssl_ctx, data->conn, in_data, in_len,
 185                         &data->tls_out_len);
 186
 187                 /* Clear reassembled input data (if the buffer was needed). */
 188                 data->tls_in_left = data->tls_in_total = data->tls_in_len = 0;
 189                 free(data->tls_in);
 190                 data->tls_in = NULL;
 191         }
 192
 193         if (data->tls_out == NULL) {
 194                 wpa_printf(MSG_DEBUG, "SSL: failed to generate output data");
 195                 data->tls_out_len = 0;
 196                 return -1;
 197         }
 198         if (data->tls_out_len == 0) {
 199                 /* TLS negotiation should now be complete since all other cases
 200                  * needing more that should have been catched above based on
 201                  * the TLS Message Length field. */
 202                 wpa_printf(MSG_DEBUG, "SSL: No data to be sent out");
 203                 free(data->tls_out);
 204                 data->tls_out = NULL;
 205
 206                 if (tls_connection_get_read_alerts(sm->ssl_ctx, data->conn)) {
 207                         wpa_printf(MSG_DEBUG, "SSL: Remote end sent a fatal "
 208                                    "alert - abort handshake");
 209                         return -1;
 210                 }
 211
 212                 return 1;
 213         }
 214
 215         wpa_printf(MSG_DEBUG, "SSL: %lu bytes left to be sent out (of total "
 216                    "%lu bytes)",
 217                    (unsigned long) data->tls_out_len - data->tls_out_pos,
 218                    (unsigned long) data->tls_out_len);
 219
 220         return 0;
 221 }
 222
 223
 224 int eap_tls_buildReq_helper(struct eap_sm *sm, struct eap_ssl_data *data,
 225                             int eap_type, int peap_version, u8 id,
 226                             u8 **out_data, size_t *out_len)
 227 {
 228         size_t len;
 229         u8 *pos, *flags;
 230         struct eap_hdr *req;
 231
 232         *out_len = 0;
 233
 234         req = malloc(sizeof(struct eap_hdr) + 2 + 4 + data->tls_out_limit);
 235         if (req == NULL) {
 236                 *out_data = NULL;
 237                 return -1;
 238         }
 239         req->code = EAP_CODE_REQUEST;
 240         req->identifier = id;
 241         pos = (u8 *) (req + 1);
 242         *pos++ = eap_type;
 243         flags = pos++;
 244         *flags = peap_version;
 245         if (data->tls_out_pos == 0 &&
 246             data->tls_out_len > data->tls_out_limit) {
 247                 *flags |= EAP_TLS_FLAGS_LENGTH_INCLUDED;
 248                 *pos++ = (data->tls_out_len >> 24) & 0xff;
 249                 *pos++ = (data->tls_out_len >> 16) & 0xff;
 250                 *pos++ = (data->tls_out_len >> 8) & 0xff;
 251                 *pos++ = data->tls_out_len & 0xff;
 252         }
 253
 254         len = data->tls_out_len - data->tls_out_pos;
 255         if (len > data->tls_out_limit) {
 256                 *flags |= EAP_TLS_FLAGS_MORE_FRAGMENTS;
 257                 len = data->tls_out_limit;
 258                 wpa_printf(MSG_DEBUG, "SSL: sending %lu bytes, more fragments "
 259                            "will follow", (unsigned long) len);
 260         }
 261         memcpy(pos, &data->tls_out[data->tls_out_pos], len);
 262         data->tls_out_pos += len;
 263         *out_len = (pos - (u8 *) req) + len;
 264         req->length = htons(*out_len);
 265         *out_data = (u8 *) req;
 266
 267         if (!(*flags & EAP_TLS_FLAGS_MORE_FRAGMENTS)) {
 268                 data->tls_out_len = 0;
 269                 data->tls_out_pos = 0;
 270                 free(data->tls_out);
 271                 data->tls_out = NULL;
 272         }
 273
 274         return 0;
 275 }
 276
 277
 278 u8 * eap_tls_build_ack(size_t *reqDataLen, u8 id, int eap_type,
 279                        int peap_version)
 280 {
 281         struct eap_hdr *req;
 282         u8 *pos;
 283
 284         *reqDataLen = sizeof(struct eap_hdr) + 2;
 285         req = malloc(*reqDataLen);
 286         if (req == NULL)
 287                 return NULL;
 288         wpa_printf(MSG_DEBUG, "SSL: Building ACK");
 289         req->code = EAP_CODE_REQUEST;
 290         req->identifier = id;
 291         req->length = htons(*reqDataLen);
 292         pos = (u8 *) (req + 1);
 293         *pos++ = eap_type; /* Type */
 294         *pos = peap_version; /* Flags */
 295         return (u8 *) req;
 296 }