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      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 (at) mit.edu).
     22  */
     23 
     24 #define NETDISSECT_REWORKED
     25 #ifdef HAVE_CONFIG_H
     26 #include "config.h"
     27 #endif
     28 
     29 #include <tcpdump-stdinc.h>
     30 
     31 #include "interface.h"
     32 #include "extract.h"
     33 
     34 static const char tstr[] = " [|kerberos]";
     35 
     36 static const u_char *c_print(netdissect_options *, register const u_char *, register const u_char *);
     37 static const u_char *krb4_print_hdr(netdissect_options *, const u_char *);
     38 static void krb4_print(netdissect_options *, const u_char *);
     39 
     40 #define AUTH_MSG_KDC_REQUEST			1<<1
     41 #define AUTH_MSG_KDC_REPLY			2<<1
     42 #define AUTH_MSG_APPL_REQUEST			3<<1
     43 #define AUTH_MSG_APPL_REQUEST_MUTUAL		4<<1
     44 #define AUTH_MSG_ERR_REPLY			5<<1
     45 #define AUTH_MSG_PRIVATE			6<<1
     46 #define AUTH_MSG_SAFE				7<<1
     47 #define AUTH_MSG_APPL_ERR			8<<1
     48 #define AUTH_MSG_DIE				63<<1
     49 
     50 #define KERB_ERR_OK				0
     51 #define KERB_ERR_NAME_EXP			1
     52 #define KERB_ERR_SERVICE_EXP			2
     53 #define KERB_ERR_AUTH_EXP			3
     54 #define KERB_ERR_PKT_VER			4
     55 #define KERB_ERR_NAME_MAST_KEY_VER		5
     56 #define KERB_ERR_SERV_MAST_KEY_VER		6
     57 #define KERB_ERR_BYTE_ORDER			7
     58 #define KERB_ERR_PRINCIPAL_UNKNOWN		8
     59 #define KERB_ERR_PRINCIPAL_NOT_UNIQUE		9
     60 #define KERB_ERR_NULL_KEY			10
     61 
     62 struct krb {
     63 	uint8_t pvno;		/* Protocol Version */
     64 	uint8_t type;		/* Type+B */
     65 };
     66 
     67 static const struct tok type2str[] = {
     68 	{ AUTH_MSG_KDC_REQUEST,		"KDC_REQUEST" },
     69 	{ AUTH_MSG_KDC_REPLY,		"KDC_REPLY" },
     70 	{ AUTH_MSG_APPL_REQUEST,	"APPL_REQUEST" },
     71 	{ AUTH_MSG_APPL_REQUEST_MUTUAL,	"APPL_REQUEST_MUTUAL" },
     72 	{ AUTH_MSG_ERR_REPLY,		"ERR_REPLY" },
     73 	{ AUTH_MSG_PRIVATE,		"PRIVATE" },
     74 	{ AUTH_MSG_SAFE,		"SAFE" },
     75 	{ AUTH_MSG_APPL_ERR,		"APPL_ERR" },
     76 	{ AUTH_MSG_DIE,			"DIE" },
     77 	{ 0,				NULL }
     78 };
     79 
     80 static const struct tok kerr2str[] = {
     81 	{ KERB_ERR_OK,			"OK" },
     82 	{ KERB_ERR_NAME_EXP,		"NAME_EXP" },
     83 	{ KERB_ERR_SERVICE_EXP,		"SERVICE_EXP" },
     84 	{ KERB_ERR_AUTH_EXP,		"AUTH_EXP" },
     85 	{ KERB_ERR_PKT_VER,		"PKT_VER" },
     86 	{ KERB_ERR_NAME_MAST_KEY_VER,	"NAME_MAST_KEY_VER" },
     87 	{ KERB_ERR_SERV_MAST_KEY_VER,	"SERV_MAST_KEY_VER" },
     88 	{ KERB_ERR_BYTE_ORDER,		"BYTE_ORDER" },
     89 	{ KERB_ERR_PRINCIPAL_UNKNOWN,	"PRINCIPAL_UNKNOWN" },
     90 	{ KERB_ERR_PRINCIPAL_NOT_UNIQUE,"PRINCIPAL_NOT_UNIQUE" },
     91 	{ KERB_ERR_NULL_KEY,		"NULL_KEY"},
     92 	{ 0,				NULL}
     93 };
     94 
     95 static const u_char *
     96 c_print(netdissect_options *ndo,
     97         register const u_char *s, register const u_char *ep)
     98 {
     99 	register u_char c;
    100 	register int flag;
    101 
    102 	flag = 1;
    103 	while (s < ep) {
    104 		c = *s++;
    105 		if (c == '\0') {
    106 			flag = 0;
    107 			break;
    108 		}
    109 		if (!ND_ISASCII(c)) {
    110 			c = ND_TOASCII(c);
    111 			ND_PRINT((ndo, "M-"));
    112 		}
    113 		if (!ND_ISPRINT(c)) {
    114 			c ^= 0x40;	/* DEL to ?, others to alpha */
    115 			ND_PRINT((ndo, "^"));
    116 		}
    117 		ND_PRINT((ndo, "%c", c));
    118 	}
    119 	if (flag)
    120 		return NULL;
    121 	return (s);
    122 }
    123 
    124 static const u_char *
    125 krb4_print_hdr(netdissect_options *ndo,
    126                const u_char *cp)
    127 {
    128 	cp += 2;
    129 
    130 #define PRINT		if ((cp = c_print(ndo, cp, ndo->ndo_snapend)) == NULL) goto trunc
    131 
    132 	PRINT;
    133 	ND_PRINT((ndo, "."));
    134 	PRINT;
    135 	ND_PRINT((ndo, "@"));
    136 	PRINT;
    137 	return (cp);
    138 
    139 trunc:
    140 	ND_PRINT((ndo, "%s", tstr));
    141 	return (NULL);
    142 
    143 #undef PRINT
    144 }
    145 
    146 static void
    147 krb4_print(netdissect_options *ndo,
    148            const u_char *cp)
    149 {
    150 	register const struct krb *kp;
    151 	u_char type;
    152 	u_short len;
    153 
    154 #define PRINT		if ((cp = c_print(ndo, cp, ndo->ndo_snapend)) == NULL) goto trunc
    155 /*  True if struct krb is little endian */
    156 #define IS_LENDIAN(kp)	(((kp)->type & 0x01) != 0)
    157 #define KTOHSP(kp, cp)	(IS_LENDIAN(kp) ? EXTRACT_LE_16BITS(cp) : EXTRACT_16BITS(cp))
    158 
    159 	kp = (struct krb *)cp;
    160 
    161 	if ((&kp->type) >= ndo->ndo_snapend) {
    162 		ND_PRINT((ndo, "%s", tstr));
    163 		return;
    164 	}
    165 
    166 	type = kp->type & (0xFF << 1);
    167 
    168 	ND_PRINT((ndo, " %s %s: ",
    169 	    IS_LENDIAN(kp) ? "le" : "be", tok2str(type2str, NULL, type)));
    170 
    171 	switch (type) {
    172 
    173 	case AUTH_MSG_KDC_REQUEST:
    174 		if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
    175 			return;
    176 		cp += 4;	/* ctime */
    177 		ND_TCHECK(*cp);
    178 		ND_PRINT((ndo, " %dmin ", *cp++ * 5));
    179 		PRINT;
    180 		ND_PRINT((ndo, "."));
    181 		PRINT;
    182 		break;
    183 
    184 	case AUTH_MSG_APPL_REQUEST:
    185 		cp += 2;
    186 		ND_TCHECK(*cp);
    187 		ND_PRINT((ndo, "v%d ", *cp++));
    188 		PRINT;
    189 		ND_TCHECK(*cp);
    190 		ND_PRINT((ndo, " (%d)", *cp++));
    191 		ND_TCHECK(*cp);
    192 		ND_PRINT((ndo, " (%d)", *cp));
    193 		break;
    194 
    195 	case AUTH_MSG_KDC_REPLY:
    196 		if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
    197 			return;
    198 		cp += 10;	/* timestamp + n + exp + kvno */
    199 		ND_TCHECK2(*cp, sizeof(short));
    200 		len = KTOHSP(kp, cp);
    201 		ND_PRINT((ndo, " (%d)", len));
    202 		break;
    203 
    204 	case AUTH_MSG_ERR_REPLY:
    205 		if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
    206 			return;
    207 		cp += 4; 	  /* timestamp */
    208 		ND_TCHECK2(*cp, sizeof(short));
    209 		ND_PRINT((ndo, " %s ", tok2str(kerr2str, NULL, KTOHSP(kp, cp))));
    210 		cp += 4;
    211 		PRINT;
    212 		break;
    213 
    214 	default:
    215 		ND_PRINT((ndo, "(unknown)"));
    216 		break;
    217 	}
    218 
    219 	return;
    220 trunc:
    221 	ND_PRINT((ndo, "%s", tstr));
    222 }
    223 
    224 void
    225 krb_print(netdissect_options *ndo,
    226           const u_char *dat)
    227 {
    228 	register const struct krb *kp;
    229 
    230 	kp = (struct krb *)dat;
    231 
    232 	if (dat >= ndo->ndo_snapend) {
    233 		ND_PRINT((ndo, "%s", tstr));
    234 		return;
    235 	}
    236 
    237 	switch (kp->pvno) {
    238 
    239 	case 1:
    240 	case 2:
    241 	case 3:
    242 		ND_PRINT((ndo, " v%d", kp->pvno));
    243 		break;
    244 
    245 	case 4:
    246 		ND_PRINT((ndo, " v%d", kp->pvno));
    247 		krb4_print(ndo, (const u_char *)kp);
    248 		break;
    249 
    250 	case 106:
    251 	case 107:
    252 		ND_PRINT((ndo, " v5"));
    253 		/* Decode ASN.1 here "someday" */
    254 		break;
    255 	}
    256 	return;
    257 }
    258