The Tcpdump Group git mirrors - tcpdump/blob - print-eap.c

   1 /*
   2  * Copyright (c) 2004 - Michael Richardson <mcr@xelerance.com>
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that: (1) source code distributions
   6  * retain the above copyright notice and this paragraph in its entirety, (2)
   7  * distributions including binary code include the above copyright notice and
   8  * this paragraph in its entirety in the documentation or other materials
   9  * provided with the distribution, and (3) all advertising materials mentioning
  10  * features or use of this software display the following acknowledgement:
  11  * ``This product includes software developed by the University of California,
  12  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  13  * the University nor the names of its contributors may be used to endorse
  14  * or promote products derived from this software without specific prior
  15  * written permission.
  16  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  17  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  19  */
  20
  21 /* \summary: Extensible Authentication Protocol (EAP) printer */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #include "netdissect-stdinc.h"
  28
  29 #include "netdissect.h"
  30 #include "extract.h"
  31
  32 #define EAP_FRAME_TYPE_PACKET           0
  33 #define EAP_FRAME_TYPE_START            1
  34 #define EAP_FRAME_TYPE_LOGOFF           2
  35 #define EAP_FRAME_TYPE_KEY              3
  36 #define EAP_FRAME_TYPE_ENCAP_ASF_ALERT  4
  37
  38 struct eap_frame_t {
  39     nd_uint8_t  version;
  40     nd_uint8_t  type;
  41     nd_uint16_t length;
  42 };
  43
  44 static const struct tok eap_frame_type_values[] = {
  45     { EAP_FRAME_TYPE_PACKET,            "EAP packet" },
  46     { EAP_FRAME_TYPE_START,             "EAPOL start" },
  47     { EAP_FRAME_TYPE_LOGOFF,            "EAPOL logoff" },
  48     { EAP_FRAME_TYPE_KEY,               "EAPOL key" },
  49     { EAP_FRAME_TYPE_ENCAP_ASF_ALERT,   "Encapsulated ASF alert" },
  50     { 0, NULL}
  51 };
  52
  53 /* RFC 3748 */
  54 struct eap_packet_t {
  55     nd_uint8_t  code;
  56     nd_uint8_t  id;
  57     nd_uint16_t length;
  58 };
  59
  60 #define         EAP_REQUEST     1
  61 #define         EAP_RESPONSE    2
  62 #define         EAP_SUCCESS     3
  63 #define         EAP_FAILURE     4
  64
  65 static const struct tok eap_code_values[] = {
  66     { EAP_REQUEST,      "Request" },
  67     { EAP_RESPONSE,     "Response" },
  68     { EAP_SUCCESS,      "Success" },
  69     { EAP_FAILURE,      "Failure" },
  70     { 0, NULL}
  71 };
  72
  73 #define         EAP_TYPE_NO_PROPOSED    0
  74 #define         EAP_TYPE_IDENTITY       1
  75 #define         EAP_TYPE_NOTIFICATION   2
  76 #define         EAP_TYPE_NAK            3
  77 #define         EAP_TYPE_MD5_CHALLENGE  4
  78 #define         EAP_TYPE_OTP            5
  79 #define         EAP_TYPE_GTC            6
  80 #define         EAP_TYPE_TLS            13              /* RFC 5216 */
  81 #define         EAP_TYPE_SIM            18              /* RFC 4186 */
  82 #define         EAP_TYPE_TTLS           21              /* RFC 5281, draft-funk-eap-ttls-v0-01.txt */
  83 #define         EAP_TYPE_AKA            23              /* RFC 4187 */
  84 #define         EAP_TYPE_FAST           43              /* RFC 4851 */
  85 #define         EAP_TYPE_EXPANDED_TYPES 254
  86 #define         EAP_TYPE_EXPERIMENTAL   255
  87
  88 static const struct tok eap_type_values[] = {
  89     { EAP_TYPE_NO_PROPOSED,     "No proposed" },
  90     { EAP_TYPE_IDENTITY,        "Identity" },
  91     { EAP_TYPE_NOTIFICATION,    "Notification" },
  92     { EAP_TYPE_NAK,             "Nak" },
  93     { EAP_TYPE_MD5_CHALLENGE,   "MD5-challenge" },
  94     { EAP_TYPE_OTP,             "OTP" },
  95     { EAP_TYPE_GTC,             "GTC" },
  96     { EAP_TYPE_TLS,             "TLS" },
  97     { EAP_TYPE_SIM,             "SIM" },
  98     { EAP_TYPE_TTLS,            "TTLS" },
  99     { EAP_TYPE_AKA,             "AKA" },
 100     { EAP_TYPE_FAST,            "FAST" },
 101     { EAP_TYPE_EXPANDED_TYPES,  "Expanded types" },
 102     { EAP_TYPE_EXPERIMENTAL,    "Experimental" },
 103     { 0, NULL}
 104 };
 105
 106 #define EAP_TLS_EXTRACT_BIT_L(x)        (((x)&0x80)>>7)
 107
 108 /* RFC 5216 - EAP TLS bits */
 109 #define EAP_TLS_FLAGS_LEN_INCLUDED              (1 << 7)
 110 #define EAP_TLS_FLAGS_MORE_FRAGMENTS            (1 << 6)
 111 #define EAP_TLS_FLAGS_START                     (1 << 5)
 112
 113 static const struct tok eap_tls_flags_values[] = {
 114         { EAP_TLS_FLAGS_LEN_INCLUDED, "L bit" },
 115         { EAP_TLS_FLAGS_MORE_FRAGMENTS, "More fragments bit"},
 116         { EAP_TLS_FLAGS_START, "Start bit"},
 117         { 0, NULL}
 118 };
 119
 120 #define EAP_TTLS_VERSION(x)             ((x)&0x07)
 121
 122 /* EAP-AKA and EAP-SIM - RFC 4187 */
 123 #define EAP_AKA_CHALLENGE               1
 124 #define EAP_AKA_AUTH_REJECT             2
 125 #define EAP_AKA_SYNC_FAILURE            4
 126 #define EAP_AKA_IDENTITY                5
 127 #define EAP_SIM_START                   10
 128 #define EAP_SIM_CHALLENGE               11
 129 #define EAP_AKA_NOTIFICATION            12
 130 #define EAP_AKA_REAUTH                  13
 131 #define EAP_AKA_CLIENT_ERROR            14
 132
 133 static const struct tok eap_aka_subtype_values[] = {
 134     { EAP_AKA_CHALLENGE,        "Challenge" },
 135     { EAP_AKA_AUTH_REJECT,      "Auth reject" },
 136     { EAP_AKA_SYNC_FAILURE,     "Sync failure" },
 137     { EAP_AKA_IDENTITY,         "Identity" },
 138     { EAP_SIM_START,            "Start" },
 139     { EAP_SIM_CHALLENGE,        "Challenge" },
 140     { EAP_AKA_NOTIFICATION,     "Notification" },
 141     { EAP_AKA_REAUTH,           "Reauth" },
 142     { EAP_AKA_CLIENT_ERROR,     "Client error" },
 143     { 0, NULL}
 144 };
 145
 146 /*
 147  * Print EAP requests / responses
 148  */
 149 void
 150 eap_print(netdissect_options *ndo,
 151           const u_char *cp,
 152           u_int length)
 153 {
 154     u_int type, subtype, len;
 155     u_int count;
 156
 157     type = GET_U_1(cp);
 158     len = GET_BE_U_2(cp + 2);
 159     if (len != length) {
 160         /*
 161          * Probably a fragment; in some cases the fragmentation might
 162          * not put an EAP header on every packet, if reassembly can
 163          * be done without that (e.g., fragmentation to make a message
 164          * fit in multiple TLVs in a RADIUS packet).
 165          */
 166         ND_PRINT("EAP fragment?");
 167         return;
 168     }
 169     ND_PRINT("%s (%u), id %u, len %u",
 170             tok2str(eap_code_values, "unknown", type),
 171             type,
 172             GET_U_1((cp + 1)),
 173             len);
 174     if (len < 4) {
 175         ND_PRINT(" (too short for EAP header)");
 176         return;
 177     }
 178
 179     ND_TCHECK_LEN(cp, len);
 180
 181     if (type == EAP_REQUEST || type == EAP_RESPONSE) {
 182         /* RFC 3748 Section 4.1 */
 183         if (len < 5) {
 184             ND_PRINT(" (too short for EAP request/response)");
 185             return;
 186         }
 187         subtype = GET_U_1(cp + 4);
 188         ND_PRINT("\n\t\t Type %s (%u)",
 189                 tok2str(eap_type_values, "unknown", subtype),
 190                 subtype);
 191
 192         switch (subtype) {
 193             case EAP_TYPE_IDENTITY:
 194                 /* According to RFC 3748, the message is optional */
 195                 if (len > 5) {
 196                     ND_PRINT(", Identity: ");
 197                     nd_printjnp(ndo, cp + 5, len - 5);
 198                 }
 199                 break;
 200
 201             case EAP_TYPE_NOTIFICATION:
 202                 /* According to RFC 3748, there must be at least one octet of message */
 203                 if (len < 6) {
 204                     ND_PRINT(" (too short for EAP Notification request/response)");
 205                     return;
 206                 }
 207                 ND_PRINT(", Notification: ");
 208                 nd_printjnp(ndo, cp + 5, len - 5);
 209                 break;
 210
 211             case EAP_TYPE_NAK:
 212                 /*
 213                  * one or more octets indicating
 214                  * the desired authentication
 215                  * type one octet per type
 216                  */
 217                 if (len < 6) {
 218                     ND_PRINT(" (too short for EAP Legacy NAK request/response)");
 219                     return;
 220                 }
 221                 for (count = 5; count < len; count++) {
 222                     ND_PRINT(" %s (%u),",
 223                            tok2str(eap_type_values, "unknown", GET_U_1((cp + count))),
 224                            GET_U_1(cp + count));
 225                 }
 226                 break;
 227
 228             case EAP_TYPE_TTLS:
 229             case EAP_TYPE_TLS:
 230                 if (len < 6) {
 231                     ND_PRINT(" (too short for EAP TLS/TTLS request/response)");
 232                     return;
 233                 }
 234                 if (subtype == EAP_TYPE_TTLS)
 235                     ND_PRINT(" TTLSv%u",
 236                            EAP_TTLS_VERSION(GET_U_1((cp + 5))));
 237                 ND_PRINT(" flags [%s] 0x%02x,",
 238                        bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
 239                        GET_U_1(cp + 5));
 240
 241                 if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
 242                     if (len < 10) {
 243                         ND_PRINT(" (too short for EAP TLS/TTLS request/response with length)");
 244                         return;
 245                     }
 246                     ND_PRINT(" len %u", GET_BE_U_4(cp + 6));
 247                 }
 248                 break;
 249
 250             case EAP_TYPE_FAST:
 251                 if (len < 6) {
 252                     ND_PRINT(" (too short for EAP FAST request/response)");
 253                     return;
 254                 }
 255                 ND_PRINT(" FASTv%u",
 256                        EAP_TTLS_VERSION(GET_U_1((cp + 5))));
 257                 ND_PRINT(" flags [%s] 0x%02x,",
 258                        bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
 259                        GET_U_1(cp + 5));
 260
 261                 if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
 262                     if (len < 10) {
 263                         ND_PRINT(" (too short for EAP FAST request/response with length)");
 264                         return;
 265                     }
 266                     ND_PRINT(" len %u", GET_BE_U_4(cp + 6));
 267                 }
 268
 269                 /* FIXME - TLV attributes follow */
 270                 break;
 271
 272             case EAP_TYPE_AKA:
 273             case EAP_TYPE_SIM:
 274                 if (len < 6) {
 275                     ND_PRINT(" (too short for EAP SIM/AKA request/response)");
 276                     return;
 277                 }
 278                 ND_PRINT(" subtype [%s] 0x%02x,",
 279                        tok2str(eap_aka_subtype_values, "unknown", GET_U_1((cp + 5))),
 280                        GET_U_1(cp + 5));
 281
 282                 /* FIXME - TLV attributes follow */
 283                 break;
 284
 285             case EAP_TYPE_MD5_CHALLENGE:
 286             case EAP_TYPE_OTP:
 287             case EAP_TYPE_GTC:
 288             case EAP_TYPE_EXPANDED_TYPES:
 289             case EAP_TYPE_EXPERIMENTAL:
 290             default:
 291                 break;
 292         }
 293     }
 294     return;
 295 trunc:
 296     nd_print_trunc(ndo);
 297 }
 298
 299 void
 300 eapol_print(netdissect_options *ndo,
 301             const u_char *cp)
 302 {
 303     const struct eap_frame_t *eap;
 304     u_int eap_type, eap_len;
 305
 306     ndo->ndo_protocol = "eap";
 307     eap = (const struct eap_frame_t *)cp;
 308     ND_TCHECK_SIZE(eap);
 309     eap_type = GET_U_1(eap->type);
 310
 311     ND_PRINT("%s (%u) v%u, len %u",
 312            tok2str(eap_frame_type_values, "unknown", eap_type),
 313            eap_type,
 314            GET_U_1(eap->version),
 315            GET_BE_U_2(eap->length));
 316     if (ndo->ndo_vflag < 1)
 317         return;
 318
 319     cp += sizeof(struct eap_frame_t);
 320     eap_len = GET_BE_U_2(eap->length);
 321
 322     switch (eap_type) {
 323     case EAP_FRAME_TYPE_PACKET:
 324         if (eap_len == 0)
 325             goto trunc;
 326         ND_PRINT(", ");
 327         eap_print(ndo, cp, eap_len);
 328         return;
 329     case EAP_FRAME_TYPE_LOGOFF:
 330     case EAP_FRAME_TYPE_ENCAP_ASF_ALERT:
 331     default:
 332         break;
 333     }
 334     return;
 335
 336  trunc:
 337     nd_print_trunc(ndo);
 338 }