1/*
2 * Copyright (c) 1995, 1996, 1997
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 *
21 * Initial contribution from John Hawkinson (jhawk@mit.edu).
22 */
23
24/* \summary: Kerberos printer */
25
26#ifdef HAVE_CONFIG_H
27#include <config.h>
28#endif
29
30#include "netdissect-stdinc.h"
31
32#include "netdissect.h"
33#include "extract.h"
34
35/*
36 * Kerberos 4:
37 *
38 * Athena Technical Plan
39 * Section E.2.1
40 * Kerberos Authentication and Authorization System
41 * by S. P. Miller, B. C. Neuman, J. I. Schiller, and J. H. Saltzer
42 *
43 * https://web.mit.edu/Saltzer/www/publications/athenaplan/e.2.1.pdf
44 *
45 * 7. Appendix I Design Specifications
46 *
47 * Kerberos 5:
48 *
49 * RFC 1510, RFC 2630, etc.
50 */
51
52
53static const u_char *c_print(netdissect_options *, const u_char *, const u_char *);
54static const u_char *krb4_print_hdr(netdissect_options *, const u_char *);
55static void krb4_print(netdissect_options *, const u_char *);
56
57#define AUTH_MSG_KDC_REQUEST			1<<1
58#define AUTH_MSG_KDC_REPLY			2<<1
59#define AUTH_MSG_APPL_REQUEST			3<<1
60#define AUTH_MSG_APPL_REQUEST_MUTUAL		4<<1
61#define AUTH_MSG_ERR_REPLY			5<<1
62#define AUTH_MSG_PRIVATE			6<<1
63#define AUTH_MSG_SAFE				7<<1
64#define AUTH_MSG_APPL_ERR			8<<1
65#define AUTH_MSG_DIE				63<<1
66
67#define KERB_ERR_OK				0
68#define KERB_ERR_NAME_EXP			1
69#define KERB_ERR_SERVICE_EXP			2
70#define KERB_ERR_AUTH_EXP			3
71#define KERB_ERR_PKT_VER			4
72#define KERB_ERR_NAME_MAST_KEY_VER		5
73#define KERB_ERR_SERV_MAST_KEY_VER		6
74#define KERB_ERR_BYTE_ORDER			7
75#define KERB_ERR_PRINCIPAL_UNKNOWN		8
76#define KERB_ERR_PRINCIPAL_NOT_UNIQUE		9
77#define KERB_ERR_NULL_KEY			10
78
79struct krb {
80	nd_uint8_t pvno;	/* Protocol Version */
81	nd_uint8_t type;	/* Type+B */
82};
83
84static const struct tok type2str[] = {
85	{ AUTH_MSG_KDC_REQUEST,		"KDC_REQUEST" },
86	{ AUTH_MSG_KDC_REPLY,		"KDC_REPLY" },
87	{ AUTH_MSG_APPL_REQUEST,	"APPL_REQUEST" },
88	{ AUTH_MSG_APPL_REQUEST_MUTUAL,	"APPL_REQUEST_MUTUAL" },
89	{ AUTH_MSG_ERR_REPLY,		"ERR_REPLY" },
90	{ AUTH_MSG_PRIVATE,		"PRIVATE" },
91	{ AUTH_MSG_SAFE,		"SAFE" },
92	{ AUTH_MSG_APPL_ERR,		"APPL_ERR" },
93	{ AUTH_MSG_DIE,			"DIE" },
94	{ 0,				NULL }
95};
96
97static const struct tok kerr2str[] = {
98	{ KERB_ERR_OK,			"OK" },
99	{ KERB_ERR_NAME_EXP,		"NAME_EXP" },
100	{ KERB_ERR_SERVICE_EXP,		"SERVICE_EXP" },
101	{ KERB_ERR_AUTH_EXP,		"AUTH_EXP" },
102	{ KERB_ERR_PKT_VER,		"PKT_VER" },
103	{ KERB_ERR_NAME_MAST_KEY_VER,	"NAME_MAST_KEY_VER" },
104	{ KERB_ERR_SERV_MAST_KEY_VER,	"SERV_MAST_KEY_VER" },
105	{ KERB_ERR_BYTE_ORDER,		"BYTE_ORDER" },
106	{ KERB_ERR_PRINCIPAL_UNKNOWN,	"PRINCIPAL_UNKNOWN" },
107	{ KERB_ERR_PRINCIPAL_NOT_UNIQUE,"PRINCIPAL_NOT_UNIQUE" },
108	{ KERB_ERR_NULL_KEY,		"NULL_KEY"},
109	{ 0,				NULL}
110};
111
112static const u_char *
113c_print(netdissect_options *ndo,
114        const u_char *s, const u_char *ep)
115{
116	u_char c;
117	int flag;
118
119	flag = 1;
120	while (s < ep) {
121		c = GET_U_1(s);
122		s++;
123		if (c == '\0') {
124			flag = 0;
125			break;
126		}
127		fn_print_char(ndo, c);
128	}
129	if (flag)
130		return NULL;
131	return (s);
132}
133
134static const u_char *
135krb4_print_hdr(netdissect_options *ndo,
136               const u_char *cp)
137{
138	cp += 2;
139
140#define PRINT		if ((cp = c_print(ndo, cp, ndo->ndo_snapend)) == NULL) goto trunc
141
142	PRINT;
143	ND_PRINT(".");
144	PRINT;
145	ND_PRINT("@");
146	PRINT;
147	return (cp);
148
149trunc:
150	nd_print_trunc(ndo);
151	return (NULL);
152
153#undef PRINT
154}
155
156static void
157krb4_print(netdissect_options *ndo,
158           const u_char *cp)
159{
160	const struct krb *kp;
161	u_char type;
162	u_short len;
163
164#define PRINT		if ((cp = c_print(ndo, cp, ndo->ndo_snapend)) == NULL) goto trunc
165/*  True if struct krb is little endian */
166#define IS_LENDIAN(kp)	((GET_U_1((kp)->type) & 0x01) != 0)
167#define KTOHSP(kp, cp)	(IS_LENDIAN(kp) ? GET_LE_U_2(cp) : GET_BE_U_2(cp))
168
169	kp = (const struct krb *)cp;
170
171	type = GET_U_1(kp->type) & (0xFF << 1);
172
173	ND_PRINT(" %s %s: ",
174	    IS_LENDIAN(kp) ? "le" : "be", tok2str(type2str, NULL, type));
175
176	switch (type) {
177
178	case AUTH_MSG_KDC_REQUEST:
179		if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
180			return;
181		cp += 4;	/* ctime */
182		ND_PRINT(" %umin ", GET_U_1(cp) * 5);
183		cp++;
184		PRINT;
185		ND_PRINT(".");
186		PRINT;
187		break;
188
189	case AUTH_MSG_APPL_REQUEST:
190		cp += 2;
191		ND_PRINT("v%u ", GET_U_1(cp));
192		cp++;
193		PRINT;
194		ND_PRINT(" (%u)", GET_U_1(cp));
195		cp++;
196		ND_PRINT(" (%u)", GET_U_1(cp));
197		break;
198
199	case AUTH_MSG_KDC_REPLY:
200		if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
201			return;
202		cp += 10;	/* timestamp + n + exp + kvno */
203		len = KTOHSP(kp, cp);
204		ND_PRINT(" (%u)", len);
205		break;
206
207	case AUTH_MSG_ERR_REPLY:
208		if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
209			return;
210		cp += 4;	  /* timestamp */
211		ND_PRINT(" %s ", tok2str(kerr2str, NULL, KTOHSP(kp, cp)));
212		cp += 4;
213		PRINT;
214		break;
215
216	default:
217		ND_PRINT("(unknown)");
218		break;
219	}
220
221	return;
222trunc:
223	nd_print_trunc(ndo);
224}
225
226void
227krb_print(netdissect_options *ndo,
228          const u_char *dat)
229{
230	const struct krb *kp;
231
232	ndo->ndo_protocol = "krb";
233	kp = (const struct krb *)dat;
234
235	if (dat >= ndo->ndo_snapend) {
236		nd_print_trunc(ndo);
237		return;
238	}
239
240	switch (GET_U_1(kp->pvno)) {
241
242	case 1:
243	case 2:
244	case 3:
245		ND_PRINT(" v%u", GET_U_1(kp->pvno));
246		break;
247
248	case 4:
249		ND_PRINT(" v%u", GET_U_1(kp->pvno));
250		krb4_print(ndo, (const u_char *)kp);
251		break;
252
253	case 106:
254	case 107:
255		ND_PRINT(" v5");
256		/* Decode ASN.1 here "someday" */
257		break;
258	}
259}
260