libeap/src/eap_common/eap_fast_common.c

   1 /*
   2  * EAP-FAST common helper functions (RFC 4851)
   3  * Copyright (c) 2008, Jouni Malinen <j@w1.fi>
   4  *
   5  * This software may be distributed under the terms of the BSD license.
   6  * See README for more details.
   7  */
   8
   9 #include "includes.h"
  10
  11 #include "common.h"
  12 #include "crypto/sha1.h"
  13 #include "crypto/tls.h"
  14 #include "eap_defs.h"
  15 #include "eap_tlv_common.h"
  16 #include "eap_fast_common.h"
  17
  18
  19 void eap_fast_put_tlv_hdr(struct wpabuf *buf, u16 type, u16 len)
  20 {
  21         struct pac_tlv_hdr hdr;
  22         hdr.type = host_to_be16(type);
  23         hdr.len = host_to_be16(len);
  24         wpabuf_put_data(buf, &hdr, sizeof(hdr));
  25 }
  26
  27
  28 void eap_fast_put_tlv(struct wpabuf *buf, u16 type, const void *data,
  29                              u16 len)
  30 {
  31         eap_fast_put_tlv_hdr(buf, type, len);
  32         wpabuf_put_data(buf, data, len);
  33 }
  34
  35
  36 void eap_fast_put_tlv_buf(struct wpabuf *buf, u16 type,
  37                                  const struct wpabuf *data)
  38 {
  39         eap_fast_put_tlv_hdr(buf, type, wpabuf_len(data));
  40         wpabuf_put_buf(buf, data);
  41 }
  42
  43
  44 struct wpabuf * eap_fast_tlv_eap_payload(struct wpabuf *buf)
  45 {
  46         struct wpabuf *e;
  47
  48         if (buf == NULL)
  49                 return NULL;
  50
  51         /* Encapsulate EAP packet in EAP-Payload TLV */
  52         wpa_printf(MSG_DEBUG, "EAP-FAST: Add EAP-Payload TLV");
  53         e = wpabuf_alloc(sizeof(struct pac_tlv_hdr) + wpabuf_len(buf));
  54         if (e == NULL) {
  55                 wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to allocate memory "
  56                            "for TLV encapsulation");
  57                 wpabuf_free(buf);
  58                 return NULL;
  59         }
  60         eap_fast_put_tlv_buf(e,
  61                              EAP_TLV_TYPE_MANDATORY | EAP_TLV_EAP_PAYLOAD_TLV,
  62                              buf);
  63         wpabuf_free(buf);
  64         return e;
  65 }
  66
  67
  68 void eap_fast_derive_master_secret(const u8 *pac_key, const u8 *server_random,
  69                                    const u8 *client_random, u8 *master_secret)
  70 {
  71 #define TLS_RANDOM_LEN 32
  72 #define TLS_MASTER_SECRET_LEN 48
  73         u8 seed[2 * TLS_RANDOM_LEN];
  74
  75         wpa_hexdump(MSG_DEBUG, "EAP-FAST: client_random",
  76                     client_random, TLS_RANDOM_LEN);
  77         wpa_hexdump(MSG_DEBUG, "EAP-FAST: server_random",
  78                     server_random, TLS_RANDOM_LEN);
  79
  80         /*
  81          * RFC 4851, Section 5.1:
  82          * master_secret = T-PRF(PAC-Key, "PAC to master secret label hash",
  83          *                       server_random + client_random, 48)
  84          */
  85         os_memcpy(seed, server_random, TLS_RANDOM_LEN);
  86         os_memcpy(seed + TLS_RANDOM_LEN, client_random, TLS_RANDOM_LEN);
  87         sha1_t_prf(pac_key, EAP_FAST_PAC_KEY_LEN,
  88                    "PAC to master secret label hash",
  89                    seed, sizeof(seed), master_secret, TLS_MASTER_SECRET_LEN);
  90
  91         wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: master_secret",
  92                         master_secret, TLS_MASTER_SECRET_LEN);
  93 }
  94
  95
  96 u8 * eap_fast_derive_key(void *ssl_ctx, struct tls_connection *conn,
  97                          const char *label, size_t len)
  98 {
  99         u8 *out;
 100
 101         out = os_malloc(len);
 102         if (out == NULL)
 103                 return NULL;
 104
 105         if (tls_connection_prf(ssl_ctx, conn, label, 1, 1, out, len)) {
 106                 os_free(out);
 107                 return NULL;
 108         }
 109
 110         return out;
 111 }
 112
 113
 114 void eap_fast_derive_eap_msk(const u8 *simck, u8 *msk)
 115 {
 116         /*
 117          * RFC 4851, Section 5.4: EAP Master Session Key Generation
 118          * MSK = T-PRF(S-IMCK[j], "Session Key Generating Function", 64)
 119          */
 120
 121         sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
 122                    "Session Key Generating Function", (u8 *) "", 0,
 123                    msk, EAP_FAST_KEY_LEN);
 124         wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (MSK)",
 125                         msk, EAP_FAST_KEY_LEN);
 126 }
 127
 128
 129 void eap_fast_derive_eap_emsk(const u8 *simck, u8 *emsk)
 130 {
 131         /*
 132          * RFC 4851, Section 5.4: EAP Master Session Key Genreration
 133          * EMSK = T-PRF(S-IMCK[j],
 134          *        "Extended Session Key Generating Function", 64)
 135          */
 136
 137         sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
 138                    "Extended Session Key Generating Function", (u8 *) "", 0,
 139                    emsk, EAP_EMSK_LEN);
 140         wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (EMSK)",
 141                         emsk, EAP_EMSK_LEN);
 142 }
 143
 144
 145 int eap_fast_parse_tlv(struct eap_fast_tlv_parse *tlv,
 146                        int tlv_type, u8 *pos, size_t len)
 147 {
 148         switch (tlv_type) {
 149         case EAP_TLV_EAP_PAYLOAD_TLV:
 150                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: EAP-Payload TLV",
 151                             pos, len);
 152                 if (tlv->eap_payload_tlv) {
 153                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 154                                    "EAP-Payload TLV in the message");
 155                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 156                         return -2;
 157                 }
 158                 tlv->eap_payload_tlv = pos;
 159                 tlv->eap_payload_tlv_len = len;
 160                 break;
 161         case EAP_TLV_RESULT_TLV:
 162                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Result TLV", pos, len);
 163                 if (tlv->result) {
 164                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 165                                    "Result TLV in the message");
 166                         tlv->result = EAP_TLV_RESULT_FAILURE;
 167                         return -2;
 168                 }
 169                 if (len < 2) {
 170                         wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
 171                                    "Result TLV");
 172                         tlv->result = EAP_TLV_RESULT_FAILURE;
 173                         break;
 174                 }
 175                 tlv->result = WPA_GET_BE16(pos);
 176                 if (tlv->result != EAP_TLV_RESULT_SUCCESS &&
 177                     tlv->result != EAP_TLV_RESULT_FAILURE) {
 178                         wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Result %d",
 179                                    tlv->result);
 180                         tlv->result = EAP_TLV_RESULT_FAILURE;
 181                 }
 182                 wpa_printf(MSG_DEBUG, "EAP-FAST: Result: %s",
 183                            tlv->result == EAP_TLV_RESULT_SUCCESS ?
 184                            "Success" : "Failure");
 185                 break;
 186         case EAP_TLV_INTERMEDIATE_RESULT_TLV:
 187                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Intermediate Result TLV",
 188                             pos, len);
 189                 if (len < 2) {
 190                         wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
 191                                    "Intermediate-Result TLV");
 192                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 193                         break;
 194                 }
 195                 if (tlv->iresult) {
 196                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 197                                    "Intermediate-Result TLV in the message");
 198                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 199                         return -2;
 200                 }
 201                 tlv->iresult = WPA_GET_BE16(pos);
 202                 if (tlv->iresult != EAP_TLV_RESULT_SUCCESS &&
 203                     tlv->iresult != EAP_TLV_RESULT_FAILURE) {
 204                         wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Intermediate "
 205                                    "Result %d", tlv->iresult);
 206                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 207                 }
 208                 wpa_printf(MSG_DEBUG, "EAP-FAST: Intermediate Result: %s",
 209                            tlv->iresult == EAP_TLV_RESULT_SUCCESS ?
 210                            "Success" : "Failure");
 211                 break;
 212         case EAP_TLV_CRYPTO_BINDING_TLV:
 213                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV",
 214                             pos, len);
 215                 if (tlv->crypto_binding) {
 216                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 217                                    "Crypto-Binding TLV in the message");
 218                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 219                         return -2;
 220                 }
 221                 tlv->crypto_binding_len = sizeof(struct eap_tlv_hdr) + len;
 222                 if (tlv->crypto_binding_len < sizeof(*tlv->crypto_binding)) {
 223                         wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
 224                                    "Crypto-Binding TLV");
 225                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 226                         return -2;
 227                 }
 228                 tlv->crypto_binding = (struct eap_tlv_crypto_binding_tlv *)
 229                         (pos - sizeof(struct eap_tlv_hdr));
 230                 break;
 231         case EAP_TLV_REQUEST_ACTION_TLV:
 232                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Request-Action TLV",
 233                             pos, len);
 234                 if (tlv->request_action) {
 235                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 236                                    "Request-Action TLV in the message");
 237                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 238                         return -2;
 239                 }
 240                 if (len < 2) {
 241                         wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
 242                                    "Request-Action TLV");
 243                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 244                         break;
 245                 }
 246                 tlv->request_action = WPA_GET_BE16(pos);
 247                 wpa_printf(MSG_DEBUG, "EAP-FAST: Request-Action: %d",
 248                            tlv->request_action);
 249                 break;
 250         case EAP_TLV_PAC_TLV:
 251                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: PAC TLV", pos, len);
 252                 if (tlv->pac) {
 253                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 254                                    "PAC TLV in the message");
 255                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 256                         return -2;
 257                 }
 258                 tlv->pac = pos;
 259                 tlv->pac_len = len;
 260                 break;
 261         default:
 262                 /* Unknown TLV */
 263                 return -1;
 264         }
 265
 266         return 0;
 267 }