1 /* 2 * EAP-FAST common helper functions (RFC 4851) 3 * Copyright (c) 2008, Jouni Malinen <j (at) 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 } 268
