The Tcpdump Group git mirrors - tcpdump/blob - print-krb.c

   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  * http://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 static const char tstr[] = " [|kerberos]";
  53
  54 static const u_char *c_print(netdissect_options *, const u_char *, const u_char *);
  55 static const u_char *krb4_print_hdr(netdissect_options *, const u_char *);
  56 static void krb4_print(netdissect_options *, const u_char *);
  57
  58 #define AUTH_MSG_KDC_REQUEST                    1<<1
  59 #define AUTH_MSG_KDC_REPLY                      2<<1
  60 #define AUTH_MSG_APPL_REQUEST                   3<<1
  61 #define AUTH_MSG_APPL_REQUEST_MUTUAL            4<<1
  62 #define AUTH_MSG_ERR_REPLY                      5<<1
  63 #define AUTH_MSG_PRIVATE                        6<<1
  64 #define AUTH_MSG_SAFE                           7<<1
  65 #define AUTH_MSG_APPL_ERR                       8<<1
  66 #define AUTH_MSG_DIE                            63<<1
  67
  68 #define KERB_ERR_OK                             0
  69 #define KERB_ERR_NAME_EXP                       1
  70 #define KERB_ERR_SERVICE_EXP                    2
  71 #define KERB_ERR_AUTH_EXP                       3
  72 #define KERB_ERR_PKT_VER                        4
  73 #define KERB_ERR_NAME_MAST_KEY_VER              5
  74 #define KERB_ERR_SERV_MAST_KEY_VER              6
  75 #define KERB_ERR_BYTE_ORDER                     7
  76 #define KERB_ERR_PRINCIPAL_UNKNOWN              8
  77 #define KERB_ERR_PRINCIPAL_NOT_UNIQUE           9
  78 #define KERB_ERR_NULL_KEY                       10
  79
  80 struct krb {
  81         nd_uint8_t pvno;        /* Protocol Version */
  82         nd_uint8_t type;        /* Type+B */
  83 };
  84
  85 static const struct tok type2str[] = {
  86         { AUTH_MSG_KDC_REQUEST,         "KDC_REQUEST" },
  87         { AUTH_MSG_KDC_REPLY,           "KDC_REPLY" },
  88         { AUTH_MSG_APPL_REQUEST,        "APPL_REQUEST" },
  89         { AUTH_MSG_APPL_REQUEST_MUTUAL, "APPL_REQUEST_MUTUAL" },
  90         { AUTH_MSG_ERR_REPLY,           "ERR_REPLY" },
  91         { AUTH_MSG_PRIVATE,             "PRIVATE" },
  92         { AUTH_MSG_SAFE,                "SAFE" },
  93         { AUTH_MSG_APPL_ERR,            "APPL_ERR" },
  94         { AUTH_MSG_DIE,                 "DIE" },
  95         { 0,                            NULL }
  96 };
  97
  98 static const struct tok kerr2str[] = {
  99         { KERB_ERR_OK,                  "OK" },
 100         { KERB_ERR_NAME_EXP,            "NAME_EXP" },
 101         { KERB_ERR_SERVICE_EXP,         "SERVICE_EXP" },
 102         { KERB_ERR_AUTH_EXP,            "AUTH_EXP" },
 103         { KERB_ERR_PKT_VER,             "PKT_VER" },
 104         { KERB_ERR_NAME_MAST_KEY_VER,   "NAME_MAST_KEY_VER" },
 105         { KERB_ERR_SERV_MAST_KEY_VER,   "SERV_MAST_KEY_VER" },
 106         { KERB_ERR_BYTE_ORDER,          "BYTE_ORDER" },
 107         { KERB_ERR_PRINCIPAL_UNKNOWN,   "PRINCIPAL_UNKNOWN" },
 108         { KERB_ERR_PRINCIPAL_NOT_UNIQUE,"PRINCIPAL_NOT_UNIQUE" },
 109         { KERB_ERR_NULL_KEY,            "NULL_KEY"},
 110         { 0,                            NULL}
 111 };
 112
 113 static const u_char *
 114 c_print(netdissect_options *ndo,
 115         const u_char *s, const u_char *ep)
 116 {
 117         u_char c;
 118         int flag;
 119
 120         flag = 1;
 121         while (s < ep) {
 122                 c = EXTRACT_U_1(s);
 123                 s++;
 124                 if (c == '\0') {
 125                         flag = 0;
 126                         break;
 127                 }
 128                 fn_print_char(ndo, c);
 129         }
 130         if (flag)
 131                 return NULL;
 132         return (s);
 133 }
 134
 135 static const u_char *
 136 krb4_print_hdr(netdissect_options *ndo,
 137                const u_char *cp)
 138 {
 139         cp += 2;
 140
 141 #define PRINT           if ((cp = c_print(ndo, cp, ndo->ndo_snapend)) == NULL) goto trunc
 142
 143         PRINT;
 144         ND_PRINT(".");
 145         PRINT;
 146         ND_PRINT("@");
 147         PRINT;
 148         return (cp);
 149
 150 trunc:
 151         ND_PRINT("%s", tstr);
 152         return (NULL);
 153
 154 #undef PRINT
 155 }
 156
 157 static void
 158 krb4_print(netdissect_options *ndo,
 159            const u_char *cp)
 160 {
 161         const struct krb *kp;
 162         u_char type;
 163         u_short len;
 164
 165 #define PRINT           if ((cp = c_print(ndo, cp, ndo->ndo_snapend)) == NULL) goto trunc
 166 /*  True if struct krb is little endian */
 167 #define IS_LENDIAN(kp)  ((EXTRACT_U_1((kp)->type) & 0x01) != 0)
 168 #define KTOHSP(kp, cp)  (IS_LENDIAN(kp) ? EXTRACT_LE_U_2(cp) : EXTRACT_BE_U_2(cp))
 169
 170         kp = (const struct krb *)cp;
 171
 172         if (!ND_TTEST_1(kp->type)) {
 173                 ND_PRINT("%s", tstr);
 174                 return;
 175         }
 176
 177         type = EXTRACT_U_1(kp->type) & (0xFF << 1);
 178
 179         ND_PRINT(" %s %s: ",
 180             IS_LENDIAN(kp) ? "le" : "be", tok2str(type2str, NULL, type));
 181
 182         switch (type) {
 183
 184         case AUTH_MSG_KDC_REQUEST:
 185                 if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
 186                         return;
 187                 cp += 4;        /* ctime */
 188                 ND_TCHECK_1(cp);
 189                 ND_PRINT(" %umin ", EXTRACT_U_1(cp) * 5);
 190                 cp++;
 191                 PRINT;
 192                 ND_PRINT(".");
 193                 PRINT;
 194                 break;
 195
 196         case AUTH_MSG_APPL_REQUEST:
 197                 cp += 2;
 198                 ND_TCHECK_1(cp);
 199                 ND_PRINT("v%u ", EXTRACT_U_1(cp));
 200                 cp++;
 201                 PRINT;
 202                 ND_TCHECK_1(cp);
 203                 ND_PRINT(" (%u)", EXTRACT_U_1(cp));
 204                 cp++;
 205                 ND_TCHECK_1(cp);
 206                 ND_PRINT(" (%u)", EXTRACT_U_1(cp));
 207                 break;
 208
 209         case AUTH_MSG_KDC_REPLY:
 210                 if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
 211                         return;
 212                 cp += 10;       /* timestamp + n + exp + kvno */
 213                 ND_TCHECK_LEN(cp, sizeof(short));
 214                 len = KTOHSP(kp, cp);
 215                 ND_PRINT(" (%u)", len);
 216                 break;
 217
 218         case AUTH_MSG_ERR_REPLY:
 219                 if ((cp = krb4_print_hdr(ndo, cp)) == NULL)
 220                         return;
 221                 cp += 4;          /* timestamp */
 222                 ND_TCHECK_LEN(cp, sizeof(short));
 223                 ND_PRINT(" %s ", tok2str(kerr2str, NULL, KTOHSP(kp, cp)));
 224                 cp += 4;
 225                 PRINT;
 226                 break;
 227
 228         default:
 229                 ND_PRINT("(unknown)");
 230                 break;
 231         }
 232
 233         return;
 234 trunc:
 235         ND_PRINT("%s", tstr);
 236 }
 237
 238 void
 239 krb_print(netdissect_options *ndo,
 240           const u_char *dat)
 241 {
 242         const struct krb *kp;
 243
 244         kp = (const struct krb *)dat;
 245
 246         if (dat >= ndo->ndo_snapend) {
 247                 ND_PRINT("%s", tstr);
 248                 return;
 249         }
 250
 251         switch (EXTRACT_U_1(kp->pvno)) {
 252
 253         case 1:
 254         case 2:
 255         case 3:
 256                 ND_PRINT(" v%u", EXTRACT_U_1(kp->pvno));
 257                 break;
 258
 259         case 4:
 260                 ND_PRINT(" v%u", EXTRACT_U_1(kp->pvno));
 261                 krb4_print(ndo, (const u_char *)kp);
 262                 break;
 263
 264         case 106:
 265         case 107:
 266                 ND_PRINT(" v5");
 267                 /* Decode ASN.1 here "someday" */
 268                 break;
 269         }
 270         return;
 271 }