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 <sys/cdefs.h>
24 #ifndef lint
25 __RCSID("$NetBSD: print-eap.c,v 1.9 2024/09/02 16:15:31 christos Exp $");
26 #endif
27
28 #include <config.h>
29
30 #include "netdissect-stdinc.h"
31
32 #include "netdissect.h"
33 #include "extract.h"
34
35 #define EAP_FRAME_TYPE_PACKET 0
36 #define EAP_FRAME_TYPE_START 1
37 #define EAP_FRAME_TYPE_LOGOFF 2
38 #define EAP_FRAME_TYPE_KEY 3
39 #define EAP_FRAME_TYPE_ENCAP_ASF_ALERT 4
40
41 struct eap_frame_t {
42 nd_uint8_t version;
43 nd_uint8_t type;
44 nd_uint16_t length;
45 };
46
47 static const struct tok eap_frame_type_values[] = {
48 { EAP_FRAME_TYPE_PACKET, "EAP packet" },
49 { EAP_FRAME_TYPE_START, "EAPOL start" },
50 { EAP_FRAME_TYPE_LOGOFF, "EAPOL logoff" },
51 { EAP_FRAME_TYPE_KEY, "EAPOL key" },
52 { EAP_FRAME_TYPE_ENCAP_ASF_ALERT, "Encapsulated ASF alert" },
53 { 0, NULL}
54 };
55
56 /* RFC 3748 */
57 struct eap_packet_t {
58 nd_uint8_t code;
59 nd_uint8_t id;
60 nd_uint16_t length;
61 };
62
63 #define EAP_REQUEST 1
64 #define EAP_RESPONSE 2
65 #define EAP_SUCCESS 3
66 #define EAP_FAILURE 4
67
68 static const struct tok eap_code_values[] = {
69 { EAP_REQUEST, "Request" },
70 { EAP_RESPONSE, "Response" },
71 { EAP_SUCCESS, "Success" },
72 { EAP_FAILURE, "Failure" },
73 { 0, NULL}
74 };
75
76 #define EAP_TYPE_NO_PROPOSED 0
77 #define EAP_TYPE_IDENTITY 1
78 #define EAP_TYPE_NOTIFICATION 2
79 #define EAP_TYPE_NAK 3
80 #define EAP_TYPE_MD5_CHALLENGE 4
81 #define EAP_TYPE_OTP 5
82 #define EAP_TYPE_GTC 6
83 #define EAP_TYPE_TLS 13 /* RFC 5216 */
84 #define EAP_TYPE_SIM 18 /* RFC 4186 */
85 #define EAP_TYPE_TTLS 21 /* RFC 5281, draft-funk-eap-ttls-v0-01.txt */
86 #define EAP_TYPE_AKA 23 /* RFC 4187 */
87 #define EAP_TYPE_FAST 43 /* RFC 4851 */
88 #define EAP_TYPE_EXPANDED_TYPES 254
89 #define EAP_TYPE_EXPERIMENTAL 255
90
91 static const struct tok eap_type_values[] = {
92 { EAP_TYPE_NO_PROPOSED, "No proposed" },
93 { EAP_TYPE_IDENTITY, "Identity" },
94 { EAP_TYPE_NOTIFICATION, "Notification" },
95 { EAP_TYPE_NAK, "Nak" },
96 { EAP_TYPE_MD5_CHALLENGE, "MD5-challenge" },
97 { EAP_TYPE_OTP, "OTP" },
98 { EAP_TYPE_GTC, "GTC" },
99 { EAP_TYPE_TLS, "TLS" },
100 { EAP_TYPE_SIM, "SIM" },
101 { EAP_TYPE_TTLS, "TTLS" },
102 { EAP_TYPE_AKA, "AKA" },
103 { EAP_TYPE_FAST, "FAST" },
104 { EAP_TYPE_EXPANDED_TYPES, "Expanded types" },
105 { EAP_TYPE_EXPERIMENTAL, "Experimental" },
106 { 0, NULL}
107 };
108
109 #define EAP_TLS_EXTRACT_BIT_L(x) (((x)&0x80)>>7)
110
111 /* RFC 5216 - EAP TLS bits */
112 #define EAP_TLS_FLAGS_LEN_INCLUDED (1 << 7)
113 #define EAP_TLS_FLAGS_MORE_FRAGMENTS (1 << 6)
114 #define EAP_TLS_FLAGS_START (1 << 5)
115
116 static const struct tok eap_tls_flags_values[] = {
117 { EAP_TLS_FLAGS_LEN_INCLUDED, "L bit" },
118 { EAP_TLS_FLAGS_MORE_FRAGMENTS, "More fragments bit"},
119 { EAP_TLS_FLAGS_START, "Start bit"},
120 { 0, NULL}
121 };
122
123 #define EAP_TTLS_VERSION(x) ((x)&0x07)
124
125 /* EAP-AKA and EAP-SIM - RFC 4187 */
126 #define EAP_AKA_CHALLENGE 1
127 #define EAP_AKA_AUTH_REJECT 2
128 #define EAP_AKA_SYNC_FAILURE 4
129 #define EAP_AKA_IDENTITY 5
130 #define EAP_SIM_START 10
131 #define EAP_SIM_CHALLENGE 11
132 #define EAP_AKA_NOTIFICATION 12
133 #define EAP_AKA_REAUTH 13
134 #define EAP_AKA_CLIENT_ERROR 14
135
136 static const struct tok eap_aka_subtype_values[] = {
137 { EAP_AKA_CHALLENGE, "Challenge" },
138 { EAP_AKA_AUTH_REJECT, "Auth reject" },
139 { EAP_AKA_SYNC_FAILURE, "Sync failure" },
140 { EAP_AKA_IDENTITY, "Identity" },
141 { EAP_SIM_START, "Start" },
142 { EAP_SIM_CHALLENGE, "Challenge" },
143 { EAP_AKA_NOTIFICATION, "Notification" },
144 { EAP_AKA_REAUTH, "Reauth" },
145 { EAP_AKA_CLIENT_ERROR, "Client error" },
146 { 0, NULL}
147 };
148
149 /*
150 * Print EAP requests / responses
151 */
152 void
eap_print(netdissect_options * ndo,const u_char * cp,u_int length)153 eap_print(netdissect_options *ndo,
154 const u_char *cp,
155 u_int length)
156 {
157 u_int type, subtype, len;
158 u_int count;
159 const char *sep;
160
161 ndo->ndo_protocol = "eap";
162 type = GET_U_1(cp);
163 len = GET_BE_U_2(cp + 2);
164 if (len != length) {
165 /*
166 * Probably a fragment; in some cases the fragmentation might
167 * not put an EAP header on every packet, if reassembly can
168 * be done without that (e.g., fragmentation to make a message
169 * fit in multiple TLVs in a RADIUS packet).
170 */
171 ND_PRINT("EAP fragment?");
172 return;
173 }
174 ND_PRINT("%s (%u), id %u, len %u",
175 tok2str(eap_code_values, "unknown", type),
176 type,
177 GET_U_1((cp + 1)),
178 len);
179 if (len < 4) {
180 ND_PRINT(" (too short for EAP header)");
181 return;
182 }
183
184 ND_TCHECK_LEN(cp, len);
185
186 if (type == EAP_REQUEST || type == EAP_RESPONSE) {
187 /* RFC 3748 Section 4.1 */
188 if (len < 5) {
189 ND_PRINT(" (too short for EAP request/response)");
190 return;
191 }
192 subtype = GET_U_1(cp + 4);
193 ND_PRINT("\n\t\t Type %s (%u)",
194 tok2str(eap_type_values, "unknown", subtype),
195 subtype);
196
197 switch (subtype) {
198 case EAP_TYPE_IDENTITY:
199 /* According to RFC 3748, the message is optional */
200 if (len > 5) {
201 ND_PRINT(", Identity: ");
202 nd_printjnp(ndo, cp + 5, len - 5);
203 }
204 break;
205
206 case EAP_TYPE_NOTIFICATION:
207 /* According to RFC 3748, there must be at least one octet of message */
208 if (len < 6) {
209 ND_PRINT(" (too short for EAP Notification request/response)");
210 return;
211 }
212 ND_PRINT(", Notification: ");
213 nd_printjnp(ndo, cp + 5, len - 5);
214 break;
215
216 case EAP_TYPE_NAK:
217 /*
218 * one or more octets indicating
219 * the desired authentication
220 * type one octet per type
221 */
222 if (len < 6) {
223 ND_PRINT(" (too short for EAP Legacy NAK request/response)");
224 return;
225 }
226 sep = "";
227 for (count = 5; count < len; count++) {
228 ND_PRINT("%s %s (%u)", sep,
229 tok2str(eap_type_values, "unknown", GET_U_1((cp + count))),
230 GET_U_1(cp + count));
231 sep = ",";
232 }
233 break;
234
235 case EAP_TYPE_TTLS:
236 case EAP_TYPE_TLS:
237 if (len < 6) {
238 ND_PRINT(" (too short for EAP TLS/TTLS request/response)");
239 return;
240 }
241 if (subtype == EAP_TYPE_TTLS)
242 ND_PRINT(" TTLSv%u",
243 EAP_TTLS_VERSION(GET_U_1((cp + 5))));
244 ND_PRINT(" flags [%s] 0x%02x",
245 bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
246 GET_U_1(cp + 5));
247
248 if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
249 if (len < 10) {
250 ND_PRINT(" (too short for EAP TLS/TTLS request/response with length)");
251 return;
252 }
253 ND_PRINT(", len %u", GET_BE_U_4(cp + 6));
254 }
255 break;
256
257 case EAP_TYPE_FAST:
258 if (len < 6) {
259 ND_PRINT(" (too short for EAP FAST request/response)");
260 return;
261 }
262 ND_PRINT(" FASTv%u",
263 EAP_TTLS_VERSION(GET_U_1((cp + 5))));
264 ND_PRINT(" flags [%s] 0x%02x",
265 bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
266 GET_U_1(cp + 5));
267
268 if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
269 if (len < 10) {
270 ND_PRINT(" (too short for EAP FAST request/response with length)");
271 return;
272 }
273 ND_PRINT(", len %u", GET_BE_U_4(cp + 6));
274 }
275
276 /* FIXME - TLV attributes follow */
277 break;
278
279 case EAP_TYPE_AKA:
280 case EAP_TYPE_SIM:
281 if (len < 6) {
282 ND_PRINT(" (too short for EAP SIM/AKA request/response)");
283 return;
284 }
285 ND_PRINT(" subtype [%s] 0x%02x",
286 tok2str(eap_aka_subtype_values, "unknown", GET_U_1((cp + 5))),
287 GET_U_1(cp + 5));
288
289 /* FIXME - TLV attributes follow */
290 break;
291
292 case EAP_TYPE_MD5_CHALLENGE:
293 case EAP_TYPE_OTP:
294 case EAP_TYPE_GTC:
295 case EAP_TYPE_EXPANDED_TYPES:
296 case EAP_TYPE_EXPERIMENTAL:
297 default:
298 break;
299 }
300 }
301 return;
302 trunc:
303 nd_print_trunc(ndo);
304 }
305
306 void
eapol_print(netdissect_options * ndo,const u_char * cp)307 eapol_print(netdissect_options *ndo,
308 const u_char *cp)
309 {
310 const struct eap_frame_t *eap;
311 u_int eap_type, eap_len;
312
313 ndo->ndo_protocol = "eap";
314 eap = (const struct eap_frame_t *)cp;
315 ND_TCHECK_SIZE(eap);
316 eap_type = GET_U_1(eap->type);
317
318 ND_PRINT("%s (%u) v%u, len %u",
319 tok2str(eap_frame_type_values, "unknown", eap_type),
320 eap_type,
321 GET_U_1(eap->version),
322 GET_BE_U_2(eap->length));
323 if (ndo->ndo_vflag < 1)
324 return;
325
326 cp += sizeof(struct eap_frame_t);
327 eap_len = GET_BE_U_2(eap->length);
328
329 switch (eap_type) {
330 case EAP_FRAME_TYPE_PACKET:
331 if (eap_len == 0)
332 goto trunc;
333 ND_PRINT(", ");
334 eap_print(ndo, cp, eap_len);
335 return;
336 case EAP_FRAME_TYPE_LOGOFF:
337 case EAP_FRAME_TYPE_ENCAP_ASF_ALERT:
338 default:
339 break;
340 }
341 return;
342
343 trunc:
344 nd_print_trunc(ndo);
345 }
346