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 #include <config.h>
24
25 #include "netdissect-stdinc.h"
26
27 #include "netdissect.h"
28 #include "extract.h"
29
30 #define EAP_FRAME_TYPE_PACKET 0
31 #define EAP_FRAME_TYPE_START 1
32 #define EAP_FRAME_TYPE_LOGOFF 2
33 #define EAP_FRAME_TYPE_KEY 3
34 #define EAP_FRAME_TYPE_ENCAP_ASF_ALERT 4
35
36 struct eap_frame_t {
37 nd_uint8_t version;
38 nd_uint8_t type;
39 nd_uint16_t length;
40 };
41
42 static const struct tok eap_frame_type_values[] = {
43 { EAP_FRAME_TYPE_PACKET, "EAP packet" },
44 { EAP_FRAME_TYPE_START, "EAPOL start" },
45 { EAP_FRAME_TYPE_LOGOFF, "EAPOL logoff" },
46 { EAP_FRAME_TYPE_KEY, "EAPOL key" },
47 { EAP_FRAME_TYPE_ENCAP_ASF_ALERT, "Encapsulated ASF alert" },
48 { 0, NULL}
49 };
50
51 /* RFC 3748 */
52 struct eap_packet_t {
53 nd_uint8_t code;
54 nd_uint8_t id;
55 nd_uint16_t length;
56 };
57
58 #define EAP_REQUEST 1
59 #define EAP_RESPONSE 2
60 #define EAP_SUCCESS 3
61 #define EAP_FAILURE 4
62
63 static const struct tok eap_code_values[] = {
64 { EAP_REQUEST, "Request" },
65 { EAP_RESPONSE, "Response" },
66 { EAP_SUCCESS, "Success" },
67 { EAP_FAILURE, "Failure" },
68 { 0, NULL}
69 };
70
71 #define EAP_TYPE_NO_PROPOSED 0
72 #define EAP_TYPE_IDENTITY 1
73 #define EAP_TYPE_NOTIFICATION 2
74 #define EAP_TYPE_NAK 3
75 #define EAP_TYPE_MD5_CHALLENGE 4
76 #define EAP_TYPE_OTP 5
77 #define EAP_TYPE_GTC 6
78 #define EAP_TYPE_TLS 13 /* RFC 5216 */
79 #define EAP_TYPE_SIM 18 /* RFC 4186 */
80 #define EAP_TYPE_TTLS 21 /* RFC 5281, draft-funk-eap-ttls-v0-01.txt */
81 #define EAP_TYPE_AKA 23 /* RFC 4187 */
82 #define EAP_TYPE_FAST 43 /* RFC 4851 */
83 #define EAP_TYPE_EXPANDED_TYPES 254
84 #define EAP_TYPE_EXPERIMENTAL 255
85
86 static const struct tok eap_type_values[] = {
87 { EAP_TYPE_NO_PROPOSED, "No proposed" },
88 { EAP_TYPE_IDENTITY, "Identity" },
89 { EAP_TYPE_NOTIFICATION, "Notification" },
90 { EAP_TYPE_NAK, "Nak" },
91 { EAP_TYPE_MD5_CHALLENGE, "MD5-challenge" },
92 { EAP_TYPE_OTP, "OTP" },
93 { EAP_TYPE_GTC, "GTC" },
94 { EAP_TYPE_TLS, "TLS" },
95 { EAP_TYPE_SIM, "SIM" },
96 { EAP_TYPE_TTLS, "TTLS" },
97 { EAP_TYPE_AKA, "AKA" },
98 { EAP_TYPE_FAST, "FAST" },
99 { EAP_TYPE_EXPANDED_TYPES, "Expanded types" },
100 { EAP_TYPE_EXPERIMENTAL, "Experimental" },
101 { 0, NULL}
102 };
103
104 #define EAP_TLS_EXTRACT_BIT_L(x) (((x)&0x80)>>7)
105
106 /* RFC 5216 - EAP TLS bits */
107 #define EAP_TLS_FLAGS_LEN_INCLUDED (1 << 7)
108 #define EAP_TLS_FLAGS_MORE_FRAGMENTS (1 << 6)
109 #define EAP_TLS_FLAGS_START (1 << 5)
110
111 static const struct tok eap_tls_flags_values[] = {
112 { EAP_TLS_FLAGS_LEN_INCLUDED, "L bit" },
113 { EAP_TLS_FLAGS_MORE_FRAGMENTS, "More fragments bit"},
114 { EAP_TLS_FLAGS_START, "Start bit"},
115 { 0, NULL}
116 };
117
118 #define EAP_TTLS_VERSION(x) ((x)&0x07)
119
120 /* EAP-AKA and EAP-SIM - RFC 4187 */
121 #define EAP_AKA_CHALLENGE 1
122 #define EAP_AKA_AUTH_REJECT 2
123 #define EAP_AKA_SYNC_FAILURE 4
124 #define EAP_AKA_IDENTITY 5
125 #define EAP_SIM_START 10
126 #define EAP_SIM_CHALLENGE 11
127 #define EAP_AKA_NOTIFICATION 12
128 #define EAP_AKA_REAUTH 13
129 #define EAP_AKA_CLIENT_ERROR 14
130
131 static const struct tok eap_aka_subtype_values[] = {
132 { EAP_AKA_CHALLENGE, "Challenge" },
133 { EAP_AKA_AUTH_REJECT, "Auth reject" },
134 { EAP_AKA_SYNC_FAILURE, "Sync failure" },
135 { EAP_AKA_IDENTITY, "Identity" },
136 { EAP_SIM_START, "Start" },
137 { EAP_SIM_CHALLENGE, "Challenge" },
138 { EAP_AKA_NOTIFICATION, "Notification" },
139 { EAP_AKA_REAUTH, "Reauth" },
140 { EAP_AKA_CLIENT_ERROR, "Client error" },
141 { 0, NULL}
142 };
143
144 /*
145 * Print EAP requests / responses
146 */
147 void
eap_print(netdissect_options * ndo,const u_char * cp,u_int length)148 eap_print(netdissect_options *ndo,
149 const u_char *cp,
150 u_int length)
151 {
152 u_int type, subtype, len;
153 u_int count;
154 const char *sep;
155
156 ndo->ndo_protocol = "eap";
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 sep = "";
222 for (count = 5; count < len; count++) {
223 ND_PRINT("%s %s (%u)", sep,
224 tok2str(eap_type_values, "unknown", GET_U_1((cp + count))),
225 GET_U_1(cp + count));
226 sep = ",";
227 }
228 break;
229
230 case EAP_TYPE_TTLS:
231 case EAP_TYPE_TLS:
232 if (len < 6) {
233 ND_PRINT(" (too short for EAP TLS/TTLS request/response)");
234 return;
235 }
236 if (subtype == EAP_TYPE_TTLS)
237 ND_PRINT(" TTLSv%u",
238 EAP_TTLS_VERSION(GET_U_1((cp + 5))));
239 ND_PRINT(" flags [%s] 0x%02x",
240 bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
241 GET_U_1(cp + 5));
242
243 if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
244 if (len < 10) {
245 ND_PRINT(" (too short for EAP TLS/TTLS request/response with length)");
246 return;
247 }
248 ND_PRINT(", len %u", GET_BE_U_4(cp + 6));
249 }
250 break;
251
252 case EAP_TYPE_FAST:
253 if (len < 6) {
254 ND_PRINT(" (too short for EAP FAST request/response)");
255 return;
256 }
257 ND_PRINT(" FASTv%u",
258 EAP_TTLS_VERSION(GET_U_1((cp + 5))));
259 ND_PRINT(" flags [%s] 0x%02x",
260 bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
261 GET_U_1(cp + 5));
262
263 if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
264 if (len < 10) {
265 ND_PRINT(" (too short for EAP FAST request/response with length)");
266 return;
267 }
268 ND_PRINT(", len %u", GET_BE_U_4(cp + 6));
269 }
270
271 /* FIXME - TLV attributes follow */
272 break;
273
274 case EAP_TYPE_AKA:
275 case EAP_TYPE_SIM:
276 if (len < 6) {
277 ND_PRINT(" (too short for EAP SIM/AKA request/response)");
278 return;
279 }
280 ND_PRINT(" subtype [%s] 0x%02x",
281 tok2str(eap_aka_subtype_values, "unknown", GET_U_1((cp + 5))),
282 GET_U_1(cp + 5));
283
284 /* FIXME - TLV attributes follow */
285 break;
286
287 case EAP_TYPE_MD5_CHALLENGE:
288 case EAP_TYPE_OTP:
289 case EAP_TYPE_GTC:
290 case EAP_TYPE_EXPANDED_TYPES:
291 case EAP_TYPE_EXPERIMENTAL:
292 default:
293 break;
294 }
295 }
296 return;
297 trunc:
298 nd_print_trunc(ndo);
299 }
300
301 void
eapol_print(netdissect_options * ndo,const u_char * cp)302 eapol_print(netdissect_options *ndo,
303 const u_char *cp)
304 {
305 const struct eap_frame_t *eap;
306 u_int eap_type, eap_len;
307
308 ndo->ndo_protocol = "eap";
309 eap = (const struct eap_frame_t *)cp;
310 ND_TCHECK_SIZE(eap);
311 eap_type = GET_U_1(eap->type);
312
313 ND_PRINT("%s (%u) v%u, len %u",
314 tok2str(eap_frame_type_values, "unknown", eap_type),
315 eap_type,
316 GET_U_1(eap->version),
317 GET_BE_U_2(eap->length));
318 if (ndo->ndo_vflag < 1)
319 return;
320
321 cp += sizeof(struct eap_frame_t);
322 eap_len = GET_BE_U_2(eap->length);
323
324 switch (eap_type) {
325 case EAP_FRAME_TYPE_PACKET:
326 if (eap_len == 0)
327 goto trunc;
328 ND_PRINT(", ");
329 eap_print(ndo, cp, eap_len);
330 return;
331 case EAP_FRAME_TYPE_LOGOFF:
332 case EAP_FRAME_TYPE_ENCAP_ASF_ALERT:
333 default:
334 break;
335 }
336 return;
337
338 trunc:
339 nd_print_trunc(ndo);
340 }
341