lib/libgssapi/gss_mech_switch.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2005 Doug Rabson
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  *      $FreeBSD$
  29  */
  30
  31 #include <gssapi/gssapi.h>
  32 #include <ctype.h>
  33 #include <dlfcn.h>
  34 #include <errno.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #include "mech_switch.h"
  40 #include "utils.h"
  41
  42 #ifndef _PATH_GSS_MECH
  43 #define _PATH_GSS_MECH  "/etc/gss/mech"
  44 #endif
  45
  46 struct _gss_mech_switch_list _gss_mechs =
  47         SLIST_HEAD_INITIALIZER(_gss_mechs);
  48 gss_OID_set _gss_mech_oids;
  49
  50 /*
  51  * Convert a string containing an OID in 'dot' form
  52  * (e.g. 1.2.840.113554.1.2.2) to a gss_OID.
  53  */
  54 static int
  55 _gss_string_to_oid(const char* s, gss_OID oid)
  56 {
  57         int                     number_count, i, j;
  58         int                     byte_count;
  59         const char              *p, *q;
  60         char                    *res;
  61
  62         oid->length = 0;
  63         oid->elements = NULL;
  64
  65         /*
  66          * First figure out how many numbers in the oid, then
  67          * calculate the compiled oid size.
  68          */
  69         number_count = 0;
  70         for (p = s; p; p = q) {
  71                 q = strchr(p, '.');
  72                 if (q) q = q + 1;
  73                 number_count++;
  74         }
  75
  76         /*
  77          * The first two numbers are in the first byte and each
  78          * subsequent number is encoded in a variable byte sequence.
  79          */
  80         if (number_count < 2)
  81                 return (EINVAL);
  82
  83         /*
  84          * We do this in two passes. The first pass, we just figure
  85          * out the size. Second time around, we actually encode the
  86          * number.
  87          */
  88         res = NULL;
  89         for (i = 0; i < 2; i++) {
  90                 byte_count = 0;
  91                 for (p = s, j = 0; p; p = q, j++) {
  92                         unsigned int number = 0;
  93
  94                         /*
  95                          * Find the end of this number.
  96                          */
  97                         q = strchr(p, '.');
  98                         if (q) q = q + 1;
  99
 100                         /*
 101                          * Read the number of of the string. Don't
 102                          * bother with anything except base ten.
 103                          */
 104                         while (*p && *p != '.') {
 105                                 number = 10 * number + (*p - '0');
 106                                 p++;
 107                         }
 108
 109                         /*
 110                          * Encode the number. The first two numbers
 111                          * are packed into the first byte. Subsequent
 112                          * numbers are encoded in bytes seven bits at
 113                          * a time with the last byte having the high
 114                          * bit set.
 115                          */
 116                         if (j == 0) {
 117                                 if (res)
 118                                         *res = number * 40;
 119                         } else if (j == 1) {
 120                                 if (res) {
 121                                         *res += number;
 122                                         res++;
 123                                 }
 124                                 byte_count++;
 125                         } else if (j >= 2) {
 126                                 /*
 127                                  * The number is encoded in seven bit chunks.
 128                                  */
 129                                 unsigned int t;
 130                                 int bytes;
 131
 132                                 bytes = 0;
 133                                 for (t = number; t; t >>= 7)
 134                                         bytes++;
 135                                 if (bytes == 0) bytes = 1;
 136                                 while (bytes) {
 137                                         if (res) {
 138                                                 int bit = 7*(bytes-1);
 139
 140                                                 *res = (number >> bit) & 0x7f;
 141                                                 if (bytes != 1)
 142                                                         *res |= 0x80;
 143                                                 res++;
 144                                         }
 145                                         byte_count++;
 146                                         bytes--;
 147                                 }
 148                         }
 149                 }
 150                 if (!res) {
 151                         res = malloc(byte_count);
 152                         if (!res)
 153                                 return (ENOMEM);
 154                         oid->length = byte_count;
 155                         oid->elements = res;
 156                 }
 157         }
 158
 159         return (0);
 160 }
 161
 162
 163 #define SYM(name)                                               \
 164 do {                                                            \
 165         snprintf(buf, sizeof(buf), "%s_%s",                     \
 166             m->gm_name_prefix, #name);                          \
 167         m->gm_ ## name = dlsym(so, buf);                        \
 168         if (!m->gm_ ## name) {                                  \
 169                 fprintf(stderr, "can't find symbol %s\n", buf); \
 170                 goto bad;                                       \
 171         }                                                       \
 172 } while (0)
 173
 174 #define OPTSYM(name)                            \
 175 do {                                            \
 176         snprintf(buf, sizeof(buf), "%s_%s",     \
 177             m->gm_name_prefix, #name);          \
 178         m->gm_ ## name = dlsym(so, buf);        \
 179 } while (0)
 180
 181 /*
 182  * Load the mechanisms file (/etc/gss/mech).
 183  */
 184 void
 185 _gss_load_mech(void)
 186 {
 187         OM_uint32       major_status, minor_status;
 188         FILE            *fp;
 189         char            buf[256];
 190         char            *p;
 191         char            *name, *oid, *lib, *kobj;
 192         struct _gss_mech_switch *m;
 193         int             count;
 194         void            *so;
 195         const char      *(*prefix_fn)(void);
 196
 197         if (SLIST_FIRST(&_gss_mechs))
 198                 return;
 199
 200         major_status = gss_create_empty_oid_set(&minor_status,
 201             &_gss_mech_oids);
 202         if (major_status)
 203                 return;
 204
 205         fp = fopen(_PATH_GSS_MECH, "r");
 206         if (!fp) {
 207                 perror(_PATH_GSS_MECH);
 208                 return;
 209         }
 210
 211         count = 0;
 212         while (fgets(buf, sizeof(buf), fp)) {
 213                 if (*buf == '#')
 214                         continue;
 215                 p = buf;
 216                 name = strsep(&p, "\t\n ");
 217                 if (p) while (isspace(*p)) p++;
 218                 oid = strsep(&p, "\t\n ");
 219                 if (p) while (isspace(*p)) p++;
 220                 lib = strsep(&p, "\t\n ");
 221                 if (p) while (isspace(*p)) p++;
 222                 kobj = strsep(&p, "\t\n ");
 223                 if (!name || !oid || !lib || !kobj)
 224                         continue;
 225
 226                 so = dlopen(lib, RTLD_LOCAL);
 227                 if (!so) {
 228                         fprintf(stderr, "dlopen: %s\n", dlerror());
 229                         continue;
 230                 }
 231
 232                 m = malloc(sizeof(struct _gss_mech_switch));
 233                 if (!m)
 234                         break;
 235                 m->gm_so = so;
 236                 if (_gss_string_to_oid(oid, &m->gm_mech_oid)) {
 237                         free(m);
 238                         continue;
 239                 }
 240
 241                 prefix_fn = (const char *(*)(void))
 242                         dlsym(so, "_gss_name_prefix");
 243                 if (prefix_fn)
 244                         m->gm_name_prefix = prefix_fn();
 245                 else
 246                         m->gm_name_prefix = "gss";
 247
 248                 major_status = gss_add_oid_set_member(&minor_status,
 249                     &m->gm_mech_oid, &_gss_mech_oids);
 250                 if (major_status) {
 251                         free(m->gm_mech_oid.elements);
 252                         free(m);
 253                         continue;
 254                 }
 255
 256                 SYM(acquire_cred);
 257                 SYM(release_cred);
 258                 SYM(init_sec_context);
 259                 SYM(accept_sec_context);
 260                 SYM(process_context_token);
 261                 SYM(delete_sec_context);
 262                 SYM(context_time);
 263                 SYM(get_mic);
 264                 SYM(verify_mic);
 265                 SYM(wrap);
 266                 SYM(unwrap);
 267                 SYM(display_status);
 268                 OPTSYM(indicate_mechs);
 269                 SYM(compare_name);
 270                 SYM(display_name);
 271                 SYM(import_name);
 272                 SYM(export_name);
 273                 SYM(release_name);
 274                 SYM(inquire_cred);
 275                 SYM(inquire_context);
 276                 SYM(wrap_size_limit);
 277                 SYM(add_cred);
 278                 SYM(inquire_cred_by_mech);
 279                 SYM(export_sec_context);
 280                 SYM(import_sec_context);
 281                 SYM(inquire_names_for_mech);
 282                 SYM(inquire_mechs_for_name);
 283                 SYM(canonicalize_name);
 284                 SYM(duplicate_name);
 285                 OPTSYM(inquire_sec_context_by_oid);
 286                 OPTSYM(inquire_cred_by_oid);
 287                 OPTSYM(set_sec_context_option);
 288                 OPTSYM(set_cred_option);
 289                 OPTSYM(pseudo_random);
 290                 OPTSYM(pname_to_uid);
 291
 292                 SLIST_INSERT_HEAD(&_gss_mechs, m, gm_link);
 293                 count++;
 294                 continue;
 295
 296         bad:
 297                 free(m->gm_mech_oid.elements);
 298                 free(m);
 299                 dlclose(so);
 300                 continue;
 301         }
 302         fclose(fp);
 303 }
 304
 305 struct _gss_mech_switch *
 306 _gss_find_mech_switch(gss_OID mech)
 307 {
 308         struct _gss_mech_switch *m;
 309
 310         _gss_load_mech();
 311         SLIST_FOREACH(m, &_gss_mechs, gm_link) {
 312                 if (gss_oid_equal(&m->gm_mech_oid, mech))
 313                         return m;
 314         }
 315         return (0);
 316 }