source4/heimdal/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_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
 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 int
 183 is_valid_plugin_filename(const char * n)
 184 {
 185     if (n[0] == '.' && (n[1] == '\0' || (n[1] == '.' && n[2] == '\0')))
 186         return 0;
 187
 188 #ifdef _WIN32
 189     /* On Windows, we only attempt to load .dll files as plug-ins. */
 190     {
 191         const char * ext;
 192
 193         ext = strrchr(n, '.');
 194         if (ext == NULL)
 195             return 0;
 196
 197         return !stricmp(ext, ".dll");
 198     }
 199 #else
 200     return 1;
 201 #endif
 202 }
 203
 204 static void
 205 trim_trailing_slash(char * path)
 206 {
 207     size_t l;
 208
 209     l = strlen(path);
 210     while (l > 0 && (path[l - 1] == '/'
 211 #ifdef BACKSLASH_PATH_DELIM
 212                      || path[l - 1] == '\\'
 213 #endif
 214                )) {
 215         path[--l] = '\0';
 216     }
 217 }
 218
 219 static krb5_error_code
 220 load_plugins(krb5_context context)
 221 {
 222     struct plugin *e;
 223     krb5_error_code ret;
 224     char **dirs = NULL, **di;
 225     struct dirent *entry;
 226     char *path;
 227     DIR *d = NULL;
 228
 229     if (!plugins_needs_scan)
 230         return 0;
 231     plugins_needs_scan = 0;
 232
 233 #ifdef HAVE_DLOPEN
 234
 235     dirs = krb5_config_get_strings(context, NULL, "libdefaults",
 236                                    "plugin_dir", NULL);
 237     if (dirs == NULL)
 238         dirs = rk_UNCONST(sysplugin_dirs);
 239
 240     for (di = dirs; *di != NULL; di++) {
 241         char * dir = *di;
 242
 243 #ifdef KRB5_USE_PATH_TOKENS
 244         if (_krb5_expand_path_tokens(context, *di, &dir))
 245             goto next_dir;
 246 #endif
 247
 248         trim_trailing_slash(dir);
 249
 250         d = opendir(dir);
 251
 252         if (d == NULL)
 253             goto next_dir;
 254
 255         rk_cloexec_dir(d);
 256
 257         while ((entry = readdir(d)) != NULL) {
 258             char *n = entry->d_name;
 259
 260             /* skip . and .. */
 261             if (!is_valid_plugin_filename(n))
 262                 continue;
 263
 264             path = NULL;
 265             ret = 0;
 266 #ifdef __APPLE__
 267             { /* support loading bundles on MacOS */
 268                 size_t len = strlen(n);
 269                 if (len > 7 && strcmp(&n[len - 7],  ".bundle") == 0)
 270                     ret = asprintf(&path, "%s/%s/Contents/MacOS/%.*s", dir, n, (int)(len - 7), n);
 271             }
 272 #endif
 273             if (ret < 0 || path == NULL)
 274                 ret = asprintf(&path, "%s/%s", dir, n);
 275
 276             if (ret < 0 || path == NULL) {
 277                 ret = ENOMEM;
 278                 krb5_set_error_message(context, ret, "malloc: out of memory");
 279                 return ret;
 280             }
 281
 282             /* check if already tried */
 283             for (e = registered; e != NULL; e = e->next)
 284                 if (e->type == DSO && strcmp(e->u.dso.path, path) == 0)
 285                     break;
 286             if (e) {
 287                 free(path);
 288             } else {
 289                 loadlib(context, path); /* store or frees path */
 290             }
 291         }
 292         closedir(d);
 293
 294     next_dir:
 295         if (dir != *di)
 296             free(dir);
 297     }
 298     if (dirs != rk_UNCONST(sysplugin_dirs))
 299         krb5_config_free_strings(dirs);
 300 #endif /* HAVE_DLOPEN */
 301     return 0;
 302 }
 303
 304 static krb5_error_code
 305 add_symbol(krb5_context context, struct krb5_plugin **list, void *symbol)
 306 {
 307     struct krb5_plugin *e;
 308
 309     e = calloc(1, sizeof(*e));
 310     if (e == NULL) {
 311         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 312         return ENOMEM;
 313     }
 314     e->symbol = symbol;
 315     e->next = *list;
 316     *list = e;
 317     return 0;
 318 }
 319
 320 krb5_error_code
 321 _krb5_plugin_find(krb5_context context,
 322                   enum krb5_plugin_type type,
 323                   const char *name,
 324                   struct krb5_plugin **list)
 325 {
 326     struct plugin *e;
 327     krb5_error_code ret;
 328
 329     *list = NULL;
 330
 331     HEIMDAL_MUTEX_lock(&plugin_mutex);
 332
 333     load_plugins(context);
 334
 335     for (ret = 0, e = registered; e != NULL; e = e->next) {
 336         switch(e->type) {
 337         case DSO: {
 338             void *sym;
 339             if (e->u.dso.dsohandle == NULL)
 340                 continue;
 341             sym = dlsym(e->u.dso.dsohandle, name);
 342             if (sym)
 343                 ret = add_symbol(context, list, sym);
 344             break;
 345         }
 346         case SYMBOL:
 347             if (strcmp(e->u.symbol.name, name) == 0 && e->u.symbol.type == type)
 348                 ret = add_symbol(context, list, e->u.symbol.symbol);
 349             break;
 350         }
 351         if (ret) {
 352             _krb5_plugin_free(*list);
 353             *list = NULL;
 354         }
 355     }
 356
 357     HEIMDAL_MUTEX_unlock(&plugin_mutex);
 358     if (ret)
 359         return ret;
 360
 361     if (*list == NULL) {
 362         krb5_set_error_message(context, ENOENT, "Did not find a plugin for %s", name);
 363         return ENOENT;
 364     }
 365
 366     return 0;
 367 }
 368
 369 void
 370 _krb5_plugin_free(struct krb5_plugin *list)
 371 {
 372     struct krb5_plugin *next;
 373     while (list) {
 374         next = list->next;
 375         free(list);
 376         list = next;
 377     }
 378 }
 379 /*
 380  * module - dict of {
 381  *      ModuleName = [
 382  *          plugin = object{
 383  *              array = { ptr, ctx }
 384  *          }
 385  *      ]
 386  * }
 387  */
 388
 389 static heim_dict_t modules;
 390
 391 struct plugin2 {
 392     heim_string_t path;
 393     void *dsohandle;
 394     heim_dict_t names;
 395 };
 396
 397 static void
 398 plug_dealloc(void *ptr)
 399 {
 400     struct plugin2 *p = ptr;
 401     heim_release(p->path);
 402     heim_release(p->names);
 403     if (p->dsohandle)
 404         dlclose(p->dsohandle);
 405 }
 406
 407
 408 void
 409 _krb5_load_plugins(krb5_context context, const char *name, const char **paths)
 410 {
 411 #ifdef HAVE_DLOPEN
 412     heim_string_t s = heim_string_create(name);
 413     heim_dict_t module;
 414     struct dirent *entry;
 415     krb5_error_code ret;
 416     const char **di;
 417     DIR *d;
 418
 419     HEIMDAL_MUTEX_lock(&plugin_mutex);
 420
 421     if (modules == NULL) {
 422         modules = heim_dict_create(11);
 423         if (modules == NULL) {
 424             HEIMDAL_MUTEX_unlock(&plugin_mutex);
 425             return;
 426         }
 427     }
 428
 429     module = heim_dict_copy_value(modules, s);
 430     if (module == NULL) {
 431         module = heim_dict_create(11);
 432         if (module == NULL) {
 433             HEIMDAL_MUTEX_unlock(&plugin_mutex);
 434             heim_release(s);
 435             return;
 436         }
 437         heim_dict_add_value(modules, s, module);
 438     }
 439     heim_release(s);
 440
 441     for (di = paths; *di != NULL; di++) {
 442         d = opendir(*di);
 443         if (d == NULL)
 444             continue;
 445         rk_cloexec_dir(d);
 446
 447         while ((entry = readdir(d)) != NULL) {
 448             char *n = entry->d_name;
 449             char *path = NULL;
 450             heim_string_t spath;
 451             struct plugin2 *p;
 452
 453             /* skip . and .. */
 454             if (n[0] == '.' && (n[1] == '\0' || (n[1] == '.' && n[2] == '\0')))
 455                 continue;
 456
 457             ret = 0;
 458 #ifdef __APPLE__
 459             { /* support loading bundles on MacOS */
 460                 size_t len = strlen(n);
 461                 if (len > 7 && strcmp(&n[len - 7],  ".bundle") == 0)
 462                     ret = asprintf(&path, "%s/%s/Contents/MacOS/%.*s", *di, n, (int)(len - 7), n);
 463             }
 464 #endif
 465             if (ret < 0 || path == NULL)
 466                 ret = asprintf(&path, "%s/%s", *di, n);
 467
 468             if (ret < 0 || path == NULL)
 469                 continue;
 470
 471             spath = heim_string_create(n);
 472             if (spath == NULL) {
 473                 free(path);
 474                 continue;
 475             }
 476
 477             /* check if already cached */
 478             p = heim_dict_copy_value(module, spath);
 479             if (p == NULL) {
 480                 p = heim_alloc(sizeof(*p), "krb5-plugin", plug_dealloc);
 481                 if (p)
 482                     p->dsohandle = dlopen(path, RTLD_LOCAL|RTLD_LAZY);
 483
 484                 if (p->dsohandle) {
 485                     p->path = heim_retain(spath);
 486                     p->names = heim_dict_create(11);
 487                     heim_dict_add_value(module, spath, p);
 488                 }
 489             }
 490             heim_release(spath);
 491             heim_release(p);
 492             free(path);
 493         }
 494         closedir(d);
 495     }
 496     heim_release(module);
 497     HEIMDAL_MUTEX_unlock(&plugin_mutex);
 498 #endif /* HAVE_DLOPEN */
 499 }
 500
 501 void
 502 _krb5_unload_plugins(krb5_context context, const char *name)
 503 {
 504     HEIMDAL_MUTEX_lock(&plugin_mutex);
 505     heim_release(modules);
 506     modules = NULL;
 507     HEIMDAL_MUTEX_unlock(&plugin_mutex);
 508 }
 509
 510 /*
 511  *
 512  */
 513
 514 struct common_plugin_method {
 515     int                 version;
 516     krb5_error_code     (*init)(krb5_context, void **);
 517     void                (*fini)(void *);
 518 };
 519
 520 struct plug {
 521     void *dataptr;
 522     void *ctx;
 523 };
 524
 525 static void
 526 plug_free(void *ptr)
 527 {
 528     struct plug *pl = ptr;
 529     if (pl->dataptr) {
 530         struct common_plugin_method *cpm = pl->dataptr;
 531         cpm->fini(pl->ctx);
 532     }
 533 }
 534
 535 struct iter_ctx {
 536     krb5_context context;
 537     heim_string_t n;
 538     const char *name;
 539     int min_version;
 540     heim_array_t result;
 541     krb5_error_code (*func)(krb5_context, const void *, void *, void *);
 542     void *userctx;
 543     krb5_error_code ret;
 544 };
 545
 546 static void
 547 search_modules(void *ctx, heim_object_t key, heim_object_t value)
 548 {
 549     struct iter_ctx *s = ctx;
 550     struct plugin2 *p = value;
 551     struct plug *pl = heim_dict_copy_value(p->names, s->n);
 552     struct common_plugin_method *cpm;
 553
 554     if (pl == NULL) {
 555         if (p->dsohandle == NULL)
 556             return;
 557
 558         pl = heim_alloc(sizeof(*pl), "struct-plug", plug_free);
 559
 560         cpm = pl->dataptr = dlsym(p->dsohandle, s->name);
 561         if (cpm) {
 562             int ret;
 563
 564             ret = cpm->init(s->context, &pl->ctx);
 565             if (ret)
 566                 cpm = pl->dataptr = NULL;
 567         }
 568         heim_dict_add_value(p->names, s->n, pl);
 569     } else {
 570         cpm = pl->dataptr;
 571     }
 572
 573     if (cpm && cpm->version >= s->min_version)
 574         heim_array_append_value(s->result, pl);
 575
 576     heim_release(pl);
 577 }
 578
 579 static void
 580 eval_results(heim_object_t value, void *ctx)
 581 {
 582     struct plug *pl = value;
 583     struct iter_ctx *s = ctx;
 584
 585     if (s->ret != KRB5_PLUGIN_NO_HANDLE)
 586         return;
 587
 588     s->ret = s->func(s->context, pl->dataptr, pl->ctx, s->userctx);
 589 }
 590
 591 krb5_error_code
 592 _krb5_plugin_run_f(krb5_context context,
 593                    const char *module,
 594                    const char *name,
 595                    int min_version,
 596                    int flags,
 597                    void *userctx,
 598                    krb5_error_code (*func)(krb5_context, const void *, void *, void *))
 599 {
 600     heim_string_t m = heim_string_create(module);
 601     heim_dict_t dict;
 602     struct iter_ctx s;
 603
 604     HEIMDAL_MUTEX_lock(&plugin_mutex);
 605
 606     dict = heim_dict_copy_value(modules, m);
 607     heim_release(m);
 608     if (dict == NULL) {
 609         HEIMDAL_MUTEX_unlock(&plugin_mutex);
 610         return KRB5_PLUGIN_NO_HANDLE;
 611     }
 612
 613     s.context = context;
 614     s.name = name;
 615     s.n = heim_string_create(name);
 616     s.min_version = min_version;
 617     s.result = heim_array_create();
 618     s.func = func;
 619     s.userctx = userctx;
 620
 621     heim_dict_iterate_f(dict, search_modules, &s);
 622
 623     heim_release(dict);
 624
 625     HEIMDAL_MUTEX_unlock(&plugin_mutex);
 626
 627     s.ret = KRB5_PLUGIN_NO_HANDLE;
 628
 629     heim_array_iterate_f(s.result, eval_results, &s);
 630
 631     heim_release(s.result);
 632     heim_release(s.n);
 633
 634     return s.ret;
 635 }