lib/libgssapi/gss_mech_switch.c

   1 /*-
   2  * Copyright (c) 2005 Doug Rabson
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  *      $FreeBSD$
  27  */
  28
  29 #include <gssapi/gssapi.h>
  30 #include <dlfcn.h>
  31 #include <errno.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35
  36 #include "mech_switch.h"
  37 #include "utils.h"
  38
  39 #ifndef _PATH_GSS_MECH
  40 #define _PATH_GSS_MECH  "/etc/gss/mech"
  41 #endif
  42
  43 struct _gss_mech_switch_list _gss_mechs =
  44         SLIST_HEAD_INITIALIZER(&_gss_mechs);
  45 gss_OID_set _gss_mech_oids;
  46
  47 /*
  48  * Convert a string containing an OID in 'dot' form
  49  * (e.g. 1.2.840.113554.1.2.2) to a gss_OID.
  50  */
  51 static int
  52 _gss_string_to_oid(const char* s, gss_OID oid)
  53 {
  54         int                     number_count, i, j;
  55         int                     byte_count;
  56         const char              *p, *q;
  57         char                    *res;
  58
  59         /*
  60          * First figure out how many numbers in the oid, then
  61          * calculate the compiled oid size.
  62          */
  63         number_count = 0;
  64         for (p = s; p; p = q) {
  65                 q = strchr(p, '.');
  66                 if (q) q = q + 1;
  67                 number_count++;
  68         }
  69
  70         /*
  71          * The first two numbers are in the first byte and each
  72          * subsequent number is encoded in a variable byte sequence.
  73          */
  74         if (number_count < 2)
  75                 return (EINVAL);
  76
  77         /*
  78          * We do this in two passes. The first pass, we just figure
  79          * out the size. Second time around, we actually encode the
  80          * number.
  81          */
  82         res = 0;
  83         for (i = 0; i < 2; i++) {
  84                 byte_count = 0;
  85                 for (p = s, j = 0; p; p = q, j++) {
  86                         unsigned int number = 0;
  87
  88                         /*
  89                          * Find the end of this number.
  90                          */
  91                         q = strchr(p, '.');
  92                         if (q) q = q + 1;
  93
  94                         /*
  95                          * Read the number of of the string. Don't
  96                          * bother with anything except base ten.
  97                          */
  98                         while (*p && *p != '.') {
  99                                 number = 10 * number + (*p - '0');
 100                                 p++;
 101                         }
 102
 103                         /*
 104                          * Encode the number. The first two numbers
 105                          * are packed into the first byte. Subsequent
 106                          * numbers are encoded in bytes seven bits at
 107                          * a time with the last byte having the high
 108                          * bit set.
 109                          */
 110                         if (j == 0) {
 111                                 if (res)
 112                                         *res = number * 40;
 113                         } else if (j == 1) {
 114                                 if (res) {
 115                                         *res += number;
 116                                         res++;
 117                                 }
 118                                 byte_count++;
 119                         } else if (j >= 2) {
 120                                 /*
 121                                  * The number is encoded in seven bit chunks.
 122                                  */
 123                                 unsigned int t;
 124                                 int bytes;
 125
 126                                 bytes = 0;
 127                                 for (t = number; t; t >>= 7)
 128                                         bytes++;
 129                                 if (bytes == 0) bytes = 1;
 130                                 while (bytes) {
 131                                         if (res) {
 132                                                 int bit = 7*(bytes-1);
 133
 134                                                 *res = (number >> bit) & 0x7f;
 135                                                 if (bytes != 1)
 136                                                         *res |= 0x80;
 137                                                 res++;
 138                                         }
 139                                         byte_count++;
 140                                         bytes--;
 141                                 }
 142                         }
 143                 }
 144                 if (!res) {
 145                         res = malloc(byte_count);
 146                         if (!res)
 147                                 return (ENOMEM);
 148                         oid->length = byte_count;
 149                         oid->elements = res;
 150                 }
 151         }
 152
 153         return (0);
 154 }
 155
 156 #define SYM(name)                                                       \
 157 do {                                                                    \
 158         m->gm_ ## name = dlsym(so, "gss_" #name);                       \
 159         if (!m->gm_ ## name) {                                          \
 160                 fprintf(stderr, "can't find symbol gss_" #name "\n");   \
 161                 goto bad;                                               \
 162         }                                                               \
 163 } while (0)
 164
 165 #define OPTSYM(name)                                                    \
 166 do {                                                                    \
 167         m->gm_ ## name = dlsym(so, "gss_" #name);                       \
 168 } while (0)
 169
 170 #define OPTSYM2(symname, ourname)                                       \
 171 do {                                                                    \
 172         m->ourname = dlsym(so, #symname);                       \
 173 } while (0)
 174
 175 /*
 176  * Load the mechanisms file (/etc/gss/mech).
 177  */
 178 void
 179 _gss_load_mech(void)
 180 {
 181         OM_uint32       major_status, minor_status;
 182         FILE            *fp;
 183         char            buf[256];
 184         char            *p;
 185         char            *name, *oid, *lib, *kobj;
 186         struct _gss_mech_switch *m;
 187         int             count;
 188         char            **pp;
 189         void            *so;
 190
 191         if (SLIST_FIRST(&_gss_mechs))
 192                 return;
 193
 194         major_status = gss_create_empty_oid_set(&minor_status,
 195             &_gss_mech_oids);
 196         if (major_status)
 197                 return;
 198
 199         fp = fopen(_PATH_GSS_MECH, "r");
 200         if (!fp) {
 201                 perror(_PATH_GSS_MECH);
 202                 return;
 203         }
 204
 205         count = 0;
 206         while (fgets(buf, sizeof(buf), fp)) {
 207                 if (*buf == '#')
 208                         continue;
 209                 p = buf;
 210                 name = strsep(&p, "\t\n ");
 211                 if (p) while (isspace(*p)) p++;
 212                 oid = strsep(&p, "\t\n ");
 213                 if (p) while (isspace(*p)) p++;
 214                 lib = strsep(&p, "\t\n ");
 215                 if (p) while (isspace(*p)) p++;
 216                 kobj = strsep(&p, "\t\n ");
 217                 if (!name || !oid || !lib || !kobj)
 218                         continue;
 219
 220                 so = dlopen(lib, RTLD_LOCAL);
 221                 if (!so) {
 222                         fprintf(stderr, "dlopen: %s\n", dlerror());
 223                         continue;
 224                 }
 225
 226                 m = malloc(sizeof(struct _gss_mech_switch));
 227                 if (!m)
 228                         break;
 229                 m->gm_so = so;
 230                 if (_gss_string_to_oid(oid, &m->gm_mech_oid)) {
 231                         free(m);
 232                         continue;
 233                 }
 234
 235                 major_status = gss_add_oid_set_member(&minor_status,
 236                     &m->gm_mech_oid, &_gss_mech_oids);
 237                 if (major_status) {
 238                         free(m->gm_mech_oid.elements);
 239                         free(m);
 240                         continue;
 241                 }
 242
 243                 SYM(acquire_cred);
 244                 SYM(release_cred);
 245                 SYM(init_sec_context);
 246                 SYM(accept_sec_context);
 247                 SYM(process_context_token);
 248                 SYM(delete_sec_context);
 249                 SYM(context_time);
 250                 SYM(get_mic);
 251                 SYM(verify_mic);
 252                 SYM(wrap);
 253                 SYM(unwrap);
 254                 SYM(display_status);
 255                 SYM(indicate_mechs);
 256                 SYM(compare_name);
 257                 SYM(display_name);
 258                 SYM(import_name);
 259                 SYM(export_name);
 260                 SYM(release_name);
 261                 SYM(inquire_cred);
 262                 SYM(inquire_context);
 263                 SYM(wrap_size_limit);
 264                 SYM(add_cred);
 265                 SYM(inquire_cred_by_mech);
 266                 SYM(export_sec_context);
 267                 SYM(import_sec_context);
 268                 SYM(inquire_names_for_mech);
 269                 SYM(inquire_mechs_for_name);
 270                 SYM(canonicalize_name);
 271                 SYM(duplicate_name);
 272                 OPTSYM2(gsskrb5_register_acceptor_identity,
 273                         gm_krb5_register_acceptor_identity);
 274                 OPTSYM(krb5_copy_ccache);
 275                 OPTSYM(krb5_compat_des3_mic);
 276
 277                 SLIST_INSERT_HEAD(&_gss_mechs, m, gm_link);
 278                 count++;
 279                 continue;
 280
 281         bad:
 282                 free(m->gm_mech_oid.elements);
 283                 free(m);
 284                 dlclose(so);
 285                 continue;
 286         }
 287         fclose(fp);
 288 }
 289
 290 struct _gss_mech_switch *
 291 _gss_find_mech_switch(gss_OID mech)
 292 {
 293         struct _gss_mech_switch *m;
 294
 295         _gss_load_mech();
 296         SLIST_FOREACH(m, &_gss_mechs, gm_link) {
 297                 if (_gss_oid_equal(&m->gm_mech_oid, mech))
 298                         return m;
 299         }
 300         return (0);
 301 }