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 <ctype.h>
  31 #include <dlfcn.h>
  32 #include <errno.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include "mech_switch.h"
  38 #include "utils.h"
  39
  40 #ifndef _PATH_GSS_MECH
  41 #define _PATH_GSS_MECH  "/etc/gss/mech"
  42 #endif
  43
  44 struct _gss_mech_switch_list _gss_mechs =
  45         SLIST_HEAD_INITIALIZER(_gss_mechs);
  46 gss_OID_set _gss_mech_oids;
  47
  48 /*
  49  * Convert a string containing an OID in 'dot' form
  50  * (e.g. 1.2.840.113554.1.2.2) to a gss_OID.
  51  */
  52 static int
  53 _gss_string_to_oid(const char* s, gss_OID oid)
  54 {
  55         int                     number_count, i, j;
  56         int                     byte_count;
  57         const char              *p, *q;
  58         char                    *res;
  59
  60         oid->length = 0;
  61         oid->elements = NULL;
  62
  63         /*
  64          * First figure out how many numbers in the oid, then
  65          * calculate the compiled oid size.
  66          */
  67         number_count = 0;
  68         for (p = s; p; p = q) {
  69                 q = strchr(p, '.');
  70                 if (q) q = q + 1;
  71                 number_count++;
  72         }
  73
  74         /*
  75          * The first two numbers are in the first byte and each
  76          * subsequent number is encoded in a variable byte sequence.
  77          */
  78         if (number_count < 2)
  79                 return (EINVAL);
  80
  81         /*
  82          * We do this in two passes. The first pass, we just figure
  83          * out the size. Second time around, we actually encode the
  84          * number.
  85          */
  86         res = 0;
  87         for (i = 0; i < 2; i++) {
  88                 byte_count = 0;
  89                 for (p = s, j = 0; p; p = q, j++) {
  90                         unsigned int number = 0;
  91
  92                         /*
  93                          * Find the end of this number.
  94                          */
  95                         q = strchr(p, '.');
  96                         if (q) q = q + 1;
  97
  98                         /*
  99                          * Read the number of of the string. Don't
 100                          * bother with anything except base ten.
 101                          */
 102                         while (*p && *p != '.') {
 103                                 number = 10 * number + (*p - '0');
 104                                 p++;
 105                         }
 106
 107                         /*
 108                          * Encode the number. The first two numbers
 109                          * are packed into the first byte. Subsequent
 110                          * numbers are encoded in bytes seven bits at
 111                          * a time with the last byte having the high
 112                          * bit set.
 113                          */
 114                         if (j == 0) {
 115                                 if (res)
 116                                         *res = number * 40;
 117                         } else if (j == 1) {
 118                                 if (res) {
 119                                         *res += number;
 120                                         res++;
 121                                 }
 122                                 byte_count++;
 123                         } else if (j >= 2) {
 124                                 /*
 125                                  * The number is encoded in seven bit chunks.
 126                                  */
 127                                 unsigned int t;
 128                                 int bytes;
 129
 130                                 bytes = 0;
 131                                 for (t = number; t; t >>= 7)
 132                                         bytes++;
 133                                 if (bytes == 0) bytes = 1;
 134                                 while (bytes) {
 135                                         if (res) {
 136                                                 int bit = 7*(bytes-1);
 137
 138                                                 *res = (number >> bit) & 0x7f;
 139                                                 if (bytes != 1)
 140                                                         *res |= 0x80;
 141                                                 res++;
 142                                         }
 143                                         byte_count++;
 144                                         bytes--;
 145                                 }
 146                         }
 147                 }
 148                 if (!res) {
 149                         res = malloc(byte_count);
 150                         if (!res)
 151                                 return (ENOMEM);
 152                         oid->length = byte_count;
 153                         oid->elements = res;
 154                 }
 155         }
 156
 157         return (0);
 158 }
 159
 160
 161 #define SYM(name)                                               \
 162 do {                                                            \
 163         snprintf(buf, sizeof(buf), "%s_%s",                     \
 164             m->gm_name_prefix, #name);                          \
 165         m->gm_ ## name = dlsym(so, buf);                        \
 166         if (!m->gm_ ## name) {                                  \
 167                 fprintf(stderr, "can't find symbol %s\n", buf); \
 168                 goto bad;                                       \
 169         }                                                       \
 170 } while (0)
 171
 172 #define OPTSYM(name)                            \
 173 do {                                            \
 174         snprintf(buf, sizeof(buf), "%s_%s",     \
 175             m->gm_name_prefix, #name);          \
 176         m->gm_ ## name = dlsym(so, buf);        \
 177 } while (0)
 178
 179 /*
 180  * Load the mechanisms file (/etc/gss/mech).
 181  */
 182 void
 183 _gss_load_mech(void)
 184 {
 185         OM_uint32       major_status, minor_status;
 186         FILE            *fp;
 187         char            buf[256];
 188         char            *p;
 189         char            *name, *oid, *lib, *kobj;
 190         struct _gss_mech_switch *m;
 191         int             count;
 192         void            *so;
 193         const char      *(*prefix_fn)(void);
 194
 195         if (SLIST_FIRST(&_gss_mechs))
 196                 return;
 197
 198         major_status = gss_create_empty_oid_set(&minor_status,
 199             &_gss_mech_oids);
 200         if (major_status)
 201                 return;
 202
 203         fp = fopen(_PATH_GSS_MECH, "r");
 204         if (!fp) {
 205                 perror(_PATH_GSS_MECH);
 206                 return;
 207         }
 208
 209         count = 0;
 210         while (fgets(buf, sizeof(buf), fp)) {
 211                 if (*buf == '#')
 212                         continue;
 213                 p = buf;
 214                 name = strsep(&p, "\t\n ");
 215                 if (p) while (isspace(*p)) p++;
 216                 oid = strsep(&p, "\t\n ");
 217                 if (p) while (isspace(*p)) p++;
 218                 lib = strsep(&p, "\t\n ");
 219                 if (p) while (isspace(*p)) p++;
 220                 kobj = strsep(&p, "\t\n ");
 221                 if (!name || !oid || !lib || !kobj)
 222                         continue;
 223
 224                 so = dlopen(lib, RTLD_LOCAL);
 225                 if (!so) {
 226                         fprintf(stderr, "dlopen: %s\n", dlerror());
 227                         continue;
 228                 }
 229
 230                 m = malloc(sizeof(struct _gss_mech_switch));
 231                 if (!m)
 232                         break;
 233                 m->gm_so = so;
 234                 if (_gss_string_to_oid(oid, &m->gm_mech_oid)) {
 235                         free(m);
 236                         continue;
 237                 }
 238
 239                 prefix_fn = (const char *(*)(void))
 240                         dlsym(so, "_gss_name_prefix");
 241                 if (prefix_fn)
 242                         m->gm_name_prefix = prefix_fn();
 243                 else
 244                         m->gm_name_prefix = "gss";
 245
 246                 major_status = gss_add_oid_set_member(&minor_status,
 247                     &m->gm_mech_oid, &_gss_mech_oids);
 248                 if (major_status) {
 249                         free(m->gm_mech_oid.elements);
 250                         free(m);
 251                         continue;
 252                 }
 253
 254                 SYM(acquire_cred);
 255                 SYM(release_cred);
 256                 SYM(init_sec_context);
 257                 SYM(accept_sec_context);
 258                 SYM(process_context_token);
 259                 SYM(delete_sec_context);
 260                 SYM(context_time);
 261                 SYM(get_mic);
 262                 SYM(verify_mic);
 263                 SYM(wrap);
 264                 SYM(unwrap);
 265                 SYM(display_status);
 266                 OPTSYM(indicate_mechs);
 267                 SYM(compare_name);
 268                 SYM(display_name);
 269                 SYM(import_name);
 270                 SYM(export_name);
 271                 SYM(release_name);
 272                 SYM(inquire_cred);
 273                 SYM(inquire_context);
 274                 SYM(wrap_size_limit);
 275                 SYM(add_cred);
 276                 SYM(inquire_cred_by_mech);
 277                 SYM(export_sec_context);
 278                 SYM(import_sec_context);
 279                 SYM(inquire_names_for_mech);
 280                 SYM(inquire_mechs_for_name);
 281                 SYM(canonicalize_name);
 282                 SYM(duplicate_name);
 283                 OPTSYM(inquire_sec_context_by_oid);
 284                 OPTSYM(inquire_cred_by_oid);
 285                 OPTSYM(set_sec_context_option);
 286                 OPTSYM(set_cred_option);
 287                 OPTSYM(pseudo_random);
 288                 OPTSYM(pname_to_uid);
 289
 290                 SLIST_INSERT_HEAD(&_gss_mechs, m, gm_link);
 291                 count++;
 292                 continue;
 293
 294         bad:
 295                 free(m->gm_mech_oid.elements);
 296                 free(m);
 297                 dlclose(so);
 298                 continue;
 299         }
 300         fclose(fp);
 301 }
 302
 303 struct _gss_mech_switch *
 304 _gss_find_mech_switch(gss_OID mech)
 305 {
 306         struct _gss_mech_switch *m;
 307
 308         _gss_load_mech();
 309         SLIST_FOREACH(m, &_gss_mechs, gm_link) {
 310                 if (gss_oid_equal(&m->gm_mech_oid, mech))
 311                         return m;
 312         }
 313         return (0);
 314 }