summaryrefslogtreecommitdiffstats
path: root/print-eap.c
blob: e154165a455f88860f01f3843888c54c6983ae6d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
/*
 * Copyright (c) 2004 - Michael Richardson <mcr@xelerance.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

/* \summary: Extensible Authentication Protocol (EAP) printer */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "netdissect-stdinc.h"

#include "netdissect.h"
#include "extract.h"

#define	EAP_FRAME_TYPE_PACKET		0
#define	EAP_FRAME_TYPE_START		1
#define	EAP_FRAME_TYPE_LOGOFF		2
#define	EAP_FRAME_TYPE_KEY		3
#define	EAP_FRAME_TYPE_ENCAP_ASF_ALERT	4

struct eap_frame_t {
    nd_uint8_t  version;
    nd_uint8_t  type;
    nd_uint16_t length;
};

static const struct tok eap_frame_type_values[] = {
    { EAP_FRAME_TYPE_PACKET,      	"EAP packet" },
    { EAP_FRAME_TYPE_START,    		"EAPOL start" },
    { EAP_FRAME_TYPE_LOGOFF,      	"EAPOL logoff" },
    { EAP_FRAME_TYPE_KEY,      		"EAPOL key" },
    { EAP_FRAME_TYPE_ENCAP_ASF_ALERT, 	"Encapsulated ASF alert" },
    { 0, NULL}
};

/* RFC 3748 */
struct eap_packet_t {
    nd_uint8_t  code;
    nd_uint8_t  id;
    nd_uint16_t length;
};

#define		EAP_REQUEST	1
#define		EAP_RESPONSE	2
#define		EAP_SUCCESS	3
#define		EAP_FAILURE	4

static const struct tok eap_code_values[] = {
    { EAP_REQUEST,	"Request" },
    { EAP_RESPONSE,	"Response" },
    { EAP_SUCCESS,	"Success" },
    { EAP_FAILURE,	"Failure" },
    { 0, NULL}
};

#define		EAP_TYPE_NO_PROPOSED	0
#define		EAP_TYPE_IDENTITY	1
#define		EAP_TYPE_NOTIFICATION	2
#define		EAP_TYPE_NAK		3
#define		EAP_TYPE_MD5_CHALLENGE	4
#define		EAP_TYPE_OTP		5
#define		EAP_TYPE_GTC		6
#define		EAP_TYPE_TLS		13		/* RFC 5216 */
#define		EAP_TYPE_SIM		18		/* RFC 4186 */
#define		EAP_TYPE_TTLS		21		/* RFC 5281, draft-funk-eap-ttls-v0-01.txt */
#define		EAP_TYPE_AKA		23		/* RFC 4187 */
#define		EAP_TYPE_FAST		43		/* RFC 4851 */
#define		EAP_TYPE_EXPANDED_TYPES	254
#define		EAP_TYPE_EXPERIMENTAL	255

static const struct tok eap_type_values[] = {
    { EAP_TYPE_NO_PROPOSED,	"No proposed" },
    { EAP_TYPE_IDENTITY,	"Identity" },
    { EAP_TYPE_NOTIFICATION,    "Notification" },
    { EAP_TYPE_NAK,      	"Nak" },
    { EAP_TYPE_MD5_CHALLENGE,   "MD5-challenge" },
    { EAP_TYPE_OTP,      	"OTP" },
    { EAP_TYPE_GTC,      	"GTC" },
    { EAP_TYPE_TLS,      	"TLS" },
    { EAP_TYPE_SIM,      	"SIM" },
    { EAP_TYPE_TTLS,      	"TTLS" },
    { EAP_TYPE_AKA,      	"AKA" },
    { EAP_TYPE_FAST,      	"FAST" },
    { EAP_TYPE_EXPANDED_TYPES,  "Expanded types" },
    { EAP_TYPE_EXPERIMENTAL,    "Experimental" },
    { 0, NULL}
};

#define EAP_TLS_EXTRACT_BIT_L(x) 	(((x)&0x80)>>7)

/* RFC 5216 - EAP TLS bits */
#define EAP_TLS_FLAGS_LEN_INCLUDED		(1 << 7)
#define EAP_TLS_FLAGS_MORE_FRAGMENTS		(1 << 6)
#define EAP_TLS_FLAGS_START			(1 << 5)

static const struct tok eap_tls_flags_values[] = {
	{ EAP_TLS_FLAGS_LEN_INCLUDED, "L bit" },
	{ EAP_TLS_FLAGS_MORE_FRAGMENTS, "More fragments bit"},
	{ EAP_TLS_FLAGS_START, "Start bit"},
	{ 0, NULL}
};

#define EAP_TTLS_VERSION(x)		((x)&0x07)

/* EAP-AKA and EAP-SIM - RFC 4187 */
#define EAP_AKA_CHALLENGE		1
#define EAP_AKA_AUTH_REJECT		2
#define EAP_AKA_SYNC_FAILURE		4
#define EAP_AKA_IDENTITY		5
#define EAP_SIM_START			10
#define EAP_SIM_CHALLENGE		11
#define EAP_AKA_NOTIFICATION		12
#define EAP_AKA_REAUTH			13
#define EAP_AKA_CLIENT_ERROR		14

static const struct tok eap_aka_subtype_values[] = {
    { EAP_AKA_CHALLENGE,	"Challenge" },
    { EAP_AKA_AUTH_REJECT,	"Auth reject" },
    { EAP_AKA_SYNC_FAILURE,	"Sync failure" },
    { EAP_AKA_IDENTITY,		"Identity" },
    { EAP_SIM_START,		"Start" },
    { EAP_SIM_CHALLENGE,	"Challenge" },
    { EAP_AKA_NOTIFICATION,	"Notification" },
    { EAP_AKA_REAUTH,		"Reauth" },
    { EAP_AKA_CLIENT_ERROR,	"Client error" },
    { 0, NULL}
};

/*
 * Print EAP requests / responses
 */
void
eap_print(netdissect_options *ndo,
          const u_char *cp,
          u_int length)
{
    u_int type, subtype, len;
    u_int count;
    const char *sep;

    type = GET_U_1(cp);
    len = GET_BE_U_2(cp + 2);
    if (len != length) {
        /*
         * Probably a fragment; in some cases the fragmentation might
         * not put an EAP header on every packet, if reassembly can
         * be done without that (e.g., fragmentation to make a message
         * fit in multiple TLVs in a RADIUS packet).
         */
        ND_PRINT("EAP fragment?");
        return;
    }
    ND_PRINT("%s (%u), id %u, len %u",
            tok2str(eap_code_values, "unknown", type),
            type,
            GET_U_1((cp + 1)),
            len);
    if (len < 4) {
        ND_PRINT(" (too short for EAP header)");
        return;
    }

    ND_TCHECK_LEN(cp, len);

    if (type == EAP_REQUEST || type == EAP_RESPONSE) {
        /* RFC 3748 Section 4.1 */
        if (len < 5) {
            ND_PRINT(" (too short for EAP request/response)");
            return;
        }
        subtype = GET_U_1(cp + 4);
        ND_PRINT("\n\t\t Type %s (%u)",
                tok2str(eap_type_values, "unknown", subtype),
                subtype);

        switch (subtype) {
            case EAP_TYPE_IDENTITY:
                /* According to RFC 3748, the message is optional */
                if (len > 5) {
                    ND_PRINT(", Identity: ");
                    nd_printjnp(ndo, cp + 5, len - 5);
                }
                break;

            case EAP_TYPE_NOTIFICATION:
                /* According to RFC 3748, there must be at least one octet of message */
                if (len < 6) {
                    ND_PRINT(" (too short for EAP Notification request/response)");
                    return;
                }
                ND_PRINT(", Notification: ");
                nd_printjnp(ndo, cp + 5, len - 5);
                break;

            case EAP_TYPE_NAK:
                /*
                 * one or more octets indicating
                 * the desired authentication
                 * type one octet per type
                 */
                if (len < 6) {
                    ND_PRINT(" (too short for EAP Legacy NAK request/response)");
                    return;
                }
                sep = "";
                for (count = 5; count < len; count++) {
                    ND_PRINT("%s %s (%u)", sep,
                           tok2str(eap_type_values, "unknown", GET_U_1((cp + count))),
                           GET_U_1(cp + count));
                    sep = ",";
                }
                break;

            case EAP_TYPE_TTLS:
            case EAP_TYPE_TLS:
                if (len < 6) {
                    ND_PRINT(" (too short for EAP TLS/TTLS request/response)");
                    return;
                }
                if (subtype == EAP_TYPE_TTLS)
                    ND_PRINT(" TTLSv%u",
                           EAP_TTLS_VERSION(GET_U_1((cp + 5))));
                ND_PRINT(" flags [%s] 0x%02x",
                       bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
                       GET_U_1(cp + 5));

                if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
                    if (len < 10) {
                        ND_PRINT(" (too short for EAP TLS/TTLS request/response with length)");
                        return;
                    }
                    ND_PRINT(", len %u", GET_BE_U_4(cp + 6));
                }
                break;

            case EAP_TYPE_FAST:
                if (len < 6) {
                    ND_PRINT(" (too short for EAP FAST request/response)");
                    return;
                }
                ND_PRINT(" FASTv%u",
                       EAP_TTLS_VERSION(GET_U_1((cp + 5))));
                ND_PRINT(" flags [%s] 0x%02x",
                       bittok2str(eap_tls_flags_values, "none", GET_U_1((cp + 5))),
                       GET_U_1(cp + 5));

                if (EAP_TLS_EXTRACT_BIT_L(GET_U_1(cp + 5))) {
                    if (len < 10) {
                        ND_PRINT(" (too short for EAP FAST request/response with length)");
                        return;
                    }
                    ND_PRINT(", len %u", GET_BE_U_4(cp + 6));
                }

                /* FIXME - TLV attributes follow */
                break;

            case EAP_TYPE_AKA:
            case EAP_TYPE_SIM:
                if (len < 6) {
                    ND_PRINT(" (too short for EAP SIM/AKA request/response)");
                    return;
                }
                ND_PRINT(" subtype [%s] 0x%02x",
                       tok2str(eap_aka_subtype_values, "unknown", GET_U_1((cp + 5))),
                       GET_U_1(cp + 5));

                /* FIXME - TLV attributes follow */
                break;

            case EAP_TYPE_MD5_CHALLENGE:
            case EAP_TYPE_OTP:
            case EAP_TYPE_GTC:
            case EAP_TYPE_EXPANDED_TYPES:
            case EAP_TYPE_EXPERIMENTAL:
            default:
                break;
        }
    }
    return;
trunc:
    nd_print_trunc(ndo);
}

void
eapol_print(netdissect_options *ndo,
            const u_char *cp)
{
    const struct eap_frame_t *eap;
    u_int eap_type, eap_len;

    ndo->ndo_protocol = "eap";
    eap = (const struct eap_frame_t *)cp;
    ND_TCHECK_SIZE(eap);
    eap_type = GET_U_1(eap->type);

    ND_PRINT("%s (%u) v%u, len %u",
           tok2str(eap_frame_type_values, "unknown", eap_type),
           eap_type,
           GET_U_1(eap->version),
           GET_BE_U_2(eap->length));
    if (ndo->ndo_vflag < 1)
        return;

    cp += sizeof(struct eap_frame_t);
    eap_len = GET_BE_U_2(eap->length);

    switch (eap_type) {
    case EAP_FRAME_TYPE_PACKET:
        if (eap_len == 0)
            goto trunc;
        ND_PRINT(", ");
        eap_print(ndo, cp, eap_len);
        return;
    case EAP_FRAME_TYPE_LOGOFF:
    case EAP_FRAME_TYPE_ENCAP_ASF_ALERT:
    default:
        break;
    }
    return;

 trunc:
    nd_print_trunc(ndo);
}