lib/krb5/plugin.c

   1 /*
   2  * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "krb5_locl.h"
  35
  36 #ifdef HAVE_DLFCN_H
  37 #include <dlfcn.h>
  38 #endif
  39 #include <dirent.h>
  40
  41 struct krb5_plugin {
  42     void *symbol;
  43     struct krb5_plugin *next;
  44 };
  45
  46 struct plugin {
  47     enum { DSO, SYMBOL } type;
  48     union {
  49         struct {
  50             char *path;
  51             void *dsohandle;
  52         } dso;
  53         struct {
  54             enum krb5_plugin_type type;
  55             char *name;
  56             char *symbol;
  57         } symbol;
  58     } u;
  59     struct plugin *next;
  60 };
  61
  62 static HEIMDAL_MUTEX plugin_mutex = HEIMDAL_MUTEX_INITIALIZER;
  63 static struct plugin *registered = NULL;
  64 static int plugins_needs_scan = 1;
  65
  66 static const char *sysplugin_dirs[] =  {
  67     LIBDIR "/plugin/krb5",
  68 #ifdef __APPLE__
  69     "/System/Library/KerberosPlugins/KerberosFrameworkPlugins",
  70 #endif
  71     NULL
  72 };
  73
  74 /*
  75  *
  76  */
  77
  78 void *
  79 _krb5_plugin_get_symbol(struct krb5_plugin *p)
  80 {
  81     return p->symbol;
  82 }
  83
  84 struct krb5_plugin *
  85 _krb5_plugin_get_next(struct krb5_plugin *p)
  86 {
  87     return p->next;
  88 }
  89
  90 /*
  91  *
  92  */
  93
  94 #ifdef HAVE_DLOPEN
  95
  96 static krb5_error_code
  97 loadlib(krb5_context context, char *path)
  98 {
  99     struct plugin *e;
 100
 101     e = calloc(1, sizeof(*e));
 102     if (e == NULL) {
 103         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 104         free(path);
 105         return ENOMEM;
 106     }
 107
 108 #ifndef RTLD_LAZY
 109 #define RTLD_LAZY 0
 110 #endif
 111 #ifndef RTLD_LOCAL
 112 #define RTLD_LOCAL 0
 113 #endif
 114     e->type = DSO;
 115     /* ignore error from dlopen, and just keep it as negative cache entry */
 116     e->u.dso.dsohandle = dlopen(path, RTLD_LOCAL|RTLD_LAZY);
 117     e->u.dso.path = path;
 118
 119     e->next = registered;
 120     registered = e;
 121
 122     return 0;
 123 }
 124 #endif /* HAVE_DLOPEN */
 125
 126 /**
 127  * Register a plugin symbol name of specific type.
 128  * @param context a Keberos context
 129  * @param type type of plugin symbol
 130  * @param name name of plugin symbol
 131  * @param symbol a pointer to the named symbol
 132  * @return In case of error a non zero error com_err error is returned
 133  * and the Kerberos error string is set.
 134  *
 135  * @ingroup krb5_support
 136  */
 137
 138 krb5_error_code
 139 krb5_plugin_register(krb5_context context,
 140                      enum krb5_plugin_type type,
 141                      const char *name,
 142                      void *symbol)
 143 {
 144     struct plugin *e;
 145
 146     HEIMDAL_MUTEX_lock(&plugin_mutex);
 147
 148     /* check for duplicates */
 149     for (e = registered; e != NULL; e = e->next) {
 150         if (e->type == SYMBOL &&
 151             strcmp(e->u.symbol.name, name) == 0 &&
 152             e->u.symbol.type == type && e->u.symbol.symbol == symbol) {
 153             HEIMDAL_MUTEX_unlock(&plugin_mutex);
 154             return 0;
 155         }
 156     }
 157
 158     e = calloc(1, sizeof(*e));
 159     if (e == NULL) {
 160         HEIMDAL_MUTEX_unlock(&plugin_mutex);
 161         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 162         return ENOMEM;
 163     }
 164     e->type = SYMBOL;
 165     e->u.symbol.type = type;
 166     e->u.symbol.name = strdup(name);
 167     if (e->u.symbol.name == NULL) {
 168         HEIMDAL_MUTEX_unlock(&plugin_mutex);
 169         free(e);
 170         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 171         return ENOMEM;
 172     }
 173     e->u.symbol.symbol = symbol;
 174
 175     e->next = registered;
 176     registered = e;
 177     HEIMDAL_MUTEX_unlock(&plugin_mutex);
 178
 179     return 0;
 180 }
 181
 182 static krb5_error_code
 183 load_plugins(krb5_context context)
 184 {
 185     struct plugin *e;
 186     krb5_error_code ret;
 187     char **dirs = NULL, **di;
 188     struct dirent *entry;
 189     char *path;
 190     DIR *d = NULL;
 191
 192     if (!plugins_needs_scan)
 193         return 0;
 194     plugins_needs_scan = 0;
 195
 196 #ifdef HAVE_DLOPEN
 197
 198     dirs = krb5_config_get_strings(context, NULL, "libdefaults",
 199                                    "plugin_dir", NULL);
 200     if (dirs == NULL)
 201         dirs = rk_UNCONST(sysplugin_dirs);
 202
 203     for (di = dirs; *di != NULL; di++) {
 204
 205         d = opendir(*di);
 206         if (d == NULL)
 207             continue;
 208         rk_cloexec(dirfd(d));
 209
 210         while ((entry = readdir(d)) != NULL) {
 211             char *n = entry->d_name;
 212
 213             /* skip . and .. */
 214             if (n[0] == '.' && (n[1] == '\0' || (n[1] == '.' && n[2] == '\0')))
 215                 continue;
 216
 217             path = NULL;
 218 #ifdef __APPLE__
 219             { /* support loading bundles on MacOS */
 220                 size_t len = strlen(n);
 221                 if (len > 7 && strcmp(&n[len - 7],  ".bundle") == 0)
 222                     asprintf(&path, "%s/%s/Contents/MacOS/%.*s", *di, n, (int)(len - 7), n);
 223             }
 224 #endif
 225             if (path == NULL)
 226                 asprintf(&path, "%s/%s", *di, n);
 227
 228             if (path == NULL) {
 229                 ret = ENOMEM;
 230                 krb5_set_error_message(context, ret, "malloc: out of memory");
 231                 return ret;
 232             }
 233
 234             /* check if already tried */
 235             for (e = registered; e != NULL; e = e->next)
 236                 if (e->type == DSO && strcmp(e->u.dso.path, path) == 0)
 237                     break;
 238             if (e) {
 239                 free(path);
 240             } else {
 241                 loadlib(context, path); /* store or frees path */
 242             }
 243         }
 244         closedir(d);
 245     }
 246     if (dirs != rk_UNCONST(sysplugin_dirs))
 247         krb5_config_free_strings(dirs);
 248 #endif /* HAVE_DLOPEN */
 249     return 0;
 250 }
 251
 252 static krb5_error_code
 253 add_symbol(krb5_context context, struct krb5_plugin **list, void *symbol)
 254 {
 255     struct krb5_plugin *e;
 256
 257     e = calloc(1, sizeof(*e));
 258     if (e == NULL) {
 259         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 260         return ENOMEM;
 261     }
 262     e->symbol = symbol;
 263     e->next = *list;
 264     *list = e;
 265     return 0;
 266 }
 267
 268 krb5_error_code
 269 _krb5_plugin_find(krb5_context context,
 270                   enum krb5_plugin_type type,
 271                   const char *name,
 272                   struct krb5_plugin **list)
 273 {
 274     struct plugin *e;
 275     krb5_error_code ret;
 276
 277     *list = NULL;
 278
 279     HEIMDAL_MUTEX_lock(&plugin_mutex);
 280
 281     load_plugins(context);
 282
 283     for (ret = 0, e = registered; e != NULL; e = e->next) {
 284         switch(e->type) {
 285         case DSO: {
 286             void *sym;
 287             if (e->u.dso.dsohandle == NULL)
 288                 continue;
 289             sym = dlsym(e->u.dso.dsohandle, name);
 290             if (sym)
 291                 ret = add_symbol(context, list, sym);
 292             break;
 293         }
 294         case SYMBOL:
 295             if (strcmp(e->u.symbol.name, name) == 0 && e->u.symbol.type == type)
 296                 ret = add_symbol(context, list, e->u.symbol.symbol);
 297             break;
 298         }
 299         if (ret) {
 300             _krb5_plugin_free(*list);
 301             *list = NULL;
 302         }
 303     }
 304
 305     HEIMDAL_MUTEX_unlock(&plugin_mutex);
 306     if (ret)
 307         return ret;
 308
 309     if (*list == NULL) {
 310         krb5_set_error_message(context, ENOENT, "Did not find a plugin for %s", name);
 311         return ENOENT;
 312     }
 313
 314     return 0;
 315 }
 316
 317 void
 318 _krb5_plugin_free(struct krb5_plugin *list)
 319 {
 320     struct krb5_plugin *next;
 321     while (list) {
 322         next = list->next;
 323         free(list);
 324         list = next;
 325     }
 326 }