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 struct tls_keys keys; 100 u8 *rnd = NULL, *out; 101 int block_size; 102 103 block_size = tls_connection_get_keyblock_size(ssl_ctx, conn); 104 if (block_size < 0) 105 return NULL; 106 107 out = os_malloc(block_size + len); 108 if (out == NULL) 109 return NULL; 110 111 if (tls_connection_prf(ssl_ctx, conn, label, 1, out, block_size + len) 112 == 0) { 113 os_memmove(out, out + block_size, len); 114 return out; 115 } 116 117 if (tls_connection_get_keys(ssl_ctx, conn, &keys)) 118 goto fail; 119 120 rnd = os_malloc(keys.client_random_len + keys.server_random_len); 121 if (rnd == NULL) 122 goto fail; 123 124 os_memcpy(rnd, keys.server_random, keys.server_random_len); 125 os_memcpy(rnd + keys.server_random_len, keys.client_random, 126 keys.client_random_len); 127 128 wpa_hexdump_key(MSG_MSGDUMP, "EAP-FAST: master_secret for key " 129 "expansion", keys.master_key, keys.master_key_len); 130 if (tls_prf_sha1_md5(keys.master_key, keys.master_key_len, 131 label, rnd, keys.client_random_len + 132 keys.server_random_len, out, block_size + len)) 133 goto fail; 134 os_free(rnd); 135 os_memmove(out, out + block_size, len); 136 return out; 137 138 fail: 139 os_free(rnd); 140 os_free(out); 141 return NULL; 142 } 143 144 145 void eap_fast_derive_eap_msk(const u8 *simck, u8 *msk) 146 { 147 /* 148 * RFC 4851, Section 5.4: EAP Master Session Key Generation 149 * MSK = T-PRF(S-IMCK[j], "Session Key Generating Function", 64) 150 */ 151 152 sha1_t_prf(simck, EAP_FAST_SIMCK_LEN, 153 "Session Key Generating Function", (u8 *) "", 0, 154 msk, EAP_FAST_KEY_LEN); 155 wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (MSK)", 156 msk, EAP_FAST_KEY_LEN); 157 } 158 159 160 void eap_fast_derive_eap_emsk(const u8 *simck, u8 *emsk) 161 { 162 /* 163 * RFC 4851, Section 5.4: EAP Master Session Key Genreration 164 * EMSK = T-PRF(S-IMCK[j], 165 * "Extended Session Key Generating Function", 64) 166 */ 167 168 sha1_t_prf(simck, EAP_FAST_SIMCK_LEN, 169 "Extended Session Key Generating Function", (u8 *) "", 0, 170 emsk, EAP_EMSK_LEN); 171 wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (EMSK)", 172 emsk, EAP_EMSK_LEN); 173 } 174 175 176 int eap_fast_parse_tlv(struct eap_fast_tlv_parse *tlv, 177 int tlv_type, u8 *pos, int len) 178 { 179 switch (tlv_type) { 180 case EAP_TLV_EAP_PAYLOAD_TLV: 181 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: EAP-Payload TLV", 182 pos, len); 183 if (tlv->eap_payload_tlv) { 184 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one " 185 "EAP-Payload TLV in the message"); 186 tlv->iresult = EAP_TLV_RESULT_FAILURE; 187 return -2; 188 } 189 tlv->eap_payload_tlv = pos; 190 tlv->eap_payload_tlv_len = len; 191 break; 192 case EAP_TLV_RESULT_TLV: 193 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Result TLV", pos, len); 194 if (tlv->result) { 195 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one " 196 "Result TLV in the message"); 197 tlv->result = EAP_TLV_RESULT_FAILURE; 198 return -2; 199 } 200 if (len < 2) { 201 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short " 202 "Result TLV"); 203 tlv->result = EAP_TLV_RESULT_FAILURE; 204 break; 205 } 206 tlv->result = WPA_GET_BE16(pos); 207 if (tlv->result != EAP_TLV_RESULT_SUCCESS && 208 tlv->result != EAP_TLV_RESULT_FAILURE) { 209 wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Result %d", 210 tlv->result); 211 tlv->result = EAP_TLV_RESULT_FAILURE; 212 } 213 wpa_printf(MSG_DEBUG, "EAP-FAST: Result: %s", 214 tlv->result == EAP_TLV_RESULT_SUCCESS ? 215 "Success" : "Failure"); 216 break; 217 case EAP_TLV_INTERMEDIATE_RESULT_TLV: 218 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Intermediate Result TLV", 219 pos, len); 220 if (len < 2) { 221 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short " 222 "Intermediate-Result TLV"); 223 tlv->iresult = EAP_TLV_RESULT_FAILURE; 224 break; 225 } 226 if (tlv->iresult) { 227 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one " 228 "Intermediate-Result TLV in the message"); 229 tlv->iresult = EAP_TLV_RESULT_FAILURE; 230 return -2; 231 } 232 tlv->iresult = WPA_GET_BE16(pos); 233 if (tlv->iresult != EAP_TLV_RESULT_SUCCESS && 234 tlv->iresult != EAP_TLV_RESULT_FAILURE) { 235 wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Intermediate " 236 "Result %d", tlv->iresult); 237 tlv->iresult = EAP_TLV_RESULT_FAILURE; 238 } 239 wpa_printf(MSG_DEBUG, "EAP-FAST: Intermediate Result: %s", 240 tlv->iresult == EAP_TLV_RESULT_SUCCESS ? 241 "Success" : "Failure"); 242 break; 243 case EAP_TLV_CRYPTO_BINDING_TLV: 244 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV", 245 pos, len); 246 if (tlv->crypto_binding) { 247 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one " 248 "Crypto-Binding TLV in the message"); 249 tlv->iresult = EAP_TLV_RESULT_FAILURE; 250 return -2; 251 } 252 tlv->crypto_binding_len = sizeof(struct eap_tlv_hdr) + len; 253 if (tlv->crypto_binding_len < sizeof(*tlv->crypto_binding)) { 254 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short " 255 "Crypto-Binding TLV"); 256 tlv->iresult = EAP_TLV_RESULT_FAILURE; 257 return -2; 258 } 259 tlv->crypto_binding = (struct eap_tlv_crypto_binding_tlv *) 260 (pos - sizeof(struct eap_tlv_hdr)); 261 break; 262 case EAP_TLV_REQUEST_ACTION_TLV: 263 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Request-Action TLV", 264 pos, len); 265 if (tlv->request_action) { 266 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one " 267 "Request-Action TLV in the message"); 268 tlv->iresult = EAP_TLV_RESULT_FAILURE; 269 return -2; 270 } 271 if (len < 2) { 272 wpa_printf(MSG_DEBUG, "EAP-FAST: Too short " 273 "Request-Action TLV"); 274 tlv->iresult = EAP_TLV_RESULT_FAILURE; 275 break; 276 } 277 tlv->request_action = WPA_GET_BE16(pos); 278 wpa_printf(MSG_DEBUG, "EAP-FAST: Request-Action: %d", 279 tlv->request_action); 280 break; 281 case EAP_TLV_PAC_TLV: 282 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: PAC TLV", pos, len); 283 if (tlv->pac) { 284 wpa_printf(MSG_DEBUG, "EAP-FAST: More than one " 285 "PAC TLV in the message"); 286 tlv->iresult = EAP_TLV_RESULT_FAILURE; 287 return -2; 288 } 289 tlv->pac = pos; 290 tlv->pac_len = len; 291 break; 292 default: 293 /* Unknown TLV */ 294 return -1; 295 } 296 297 return 0; 298 } 299