kcm/events.c

   1 /*
   2  * Copyright (c) 2005, PADL Software Pty Ltd.
   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  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  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  * 3. Neither the name of PADL Software nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY PADL SOFTWARE AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL PADL SOFTWARE OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include "kcm_locl.h"
  34
  35 RCSID("$Id$");
  36
  37 /* thread-safe in case we multi-thread later */
  38 static HEIMDAL_MUTEX events_mutex = HEIMDAL_MUTEX_INITIALIZER;
  39 static kcm_event *events_head = NULL;
  40 static time_t last_run = 0;
  41
  42 static char *action_strings[] = {
  43         "NONE", "ACQUIRE_CREDS", "RENEW_CREDS",
  44         "DESTROY_CREDS", "DESTROY_EMPTY_CACHE" };
  45
  46 krb5_error_code
  47 kcm_enqueue_event(krb5_context context,
  48                   kcm_event *event)
  49 {
  50     krb5_error_code ret;
  51
  52     if (event->action == KCM_EVENT_NONE) {
  53         return 0;
  54     }
  55
  56     HEIMDAL_MUTEX_lock(&events_mutex);
  57     ret = kcm_enqueue_event_internal(context, event);
  58     HEIMDAL_MUTEX_unlock(&events_mutex);
  59
  60     return ret;
  61 }
  62
  63 static void
  64 print_times(time_t t, char buf[64])
  65 {
  66     if (t)
  67         strftime(buf, 64, "%m-%dT%H:%M", gmtime(&t));
  68     else
  69         strlcpy(buf, "never", 64);
  70 }
  71
  72 static void
  73 log_event(kcm_event *event, char *msg)
  74 {
  75     char fire_time[64], expire_time[64];
  76
  77     print_times(event->fire_time, fire_time);
  78     print_times(event->expire_time, expire_time);
  79
  80     kcm_log(7, "%s event %08x: fire_time %s fire_count %d expire_time %s "
  81             "backoff_time %d action %s cache %s",
  82             msg, event, fire_time, event->fire_count, expire_time,
  83             event->backoff_time, action_strings[event->action],
  84             event->ccache->name);
  85 }
  86
  87 krb5_error_code
  88 kcm_enqueue_event_internal(krb5_context context,
  89                            kcm_event *event)
  90 {
  91     kcm_event **e;
  92
  93     if (event->action == KCM_EVENT_NONE)
  94         return 0;
  95
  96     for (e = &events_head; *e != NULL; e = &(*e)->next)
  97         ;
  98
  99     *e = (kcm_event *)malloc(sizeof(kcm_event));
 100     if (*e == NULL) {
 101         return KRB5_CC_NOMEM;
 102     }
 103
 104     (*e)->valid = 1;
 105     (*e)->fire_time = event->fire_time;
 106     (*e)->fire_count = 0;
 107     (*e)->expire_time = event->expire_time;
 108     (*e)->backoff_time = event->backoff_time;
 109
 110     (*e)->action = event->action;
 111
 112     kcm_retain_ccache(context, event->ccache);
 113     (*e)->ccache = event->ccache;
 114     (*e)->next = NULL;
 115
 116     log_event(*e, "enqueuing");
 117
 118     return 0;
 119 }
 120
 121 /*
 122  * Dump events list on SIGUSR2
 123  */
 124 krb5_error_code
 125 kcm_debug_events(krb5_context context)
 126 {
 127     kcm_event *e;
 128
 129     for (e = events_head; e != NULL; e = e->next)
 130         log_event(e, "debug");
 131
 132     return 0;
 133 }
 134
 135 krb5_error_code
 136 kcm_enqueue_event_relative(krb5_context context,
 137                            kcm_event *event)
 138 {
 139     krb5_error_code ret;
 140     kcm_event e;
 141
 142     e = *event;
 143     e.backoff_time = e.fire_time;
 144     e.fire_time += time(NULL);
 145
 146     ret = kcm_enqueue_event(context, &e);
 147
 148     return ret;
 149 }
 150
 151 static krb5_error_code
 152 kcm_remove_event_internal(krb5_context context,
 153                           kcm_event **e)
 154 {
 155     kcm_event *next;
 156
 157     next = (*e)->next;
 158
 159     (*e)->valid = 0;
 160     (*e)->fire_time = 0;
 161     (*e)->fire_count = 0;
 162     (*e)->expire_time = 0;
 163     (*e)->backoff_time = 0;
 164     kcm_release_ccache(context, (*e)->ccache);
 165     (*e)->next = NULL;
 166     free(*e);
 167
 168     *e = next;
 169
 170     return 0;
 171 }
 172
 173 static int
 174 is_primary_credential_p(krb5_context context,
 175                         kcm_ccache ccache,
 176                         krb5_creds *newcred)
 177 {
 178     krb5_flags whichfields;
 179
 180     if (ccache->client == NULL)
 181         return 0;
 182
 183     if (newcred->client == NULL ||
 184         !krb5_principal_compare(context, ccache->client, newcred->client))
 185         return 0;
 186
 187     /* XXX just checks whether it's the first credential in the cache */
 188     if (ccache->creds == NULL)
 189         return 0;
 190
 191     whichfields = KRB5_TC_MATCH_KEYTYPE | KRB5_TC_MATCH_FLAGS_EXACT |
 192                   KRB5_TC_MATCH_TIMES_EXACT | KRB5_TC_MATCH_AUTHDATA |
 193                   KRB5_TC_MATCH_2ND_TKT | KRB5_TC_MATCH_IS_SKEY;
 194
 195     return krb5_compare_creds(context, whichfields, newcred, &ccache->creds->cred);
 196 }
 197
 198 /*
 199  * Setup default events for a new credential
 200  */
 201 static krb5_error_code
 202 kcm_ccache_make_default_event(krb5_context context,
 203                               kcm_event *event,
 204                               krb5_creds *newcred)
 205 {
 206     krb5_error_code ret = 0;
 207     kcm_ccache ccache = event->ccache;
 208
 209     event->fire_time = 0;
 210     event->expire_time = 0;
 211     event->backoff_time = KCM_EVENT_DEFAULT_BACKOFF_TIME;
 212
 213     if (newcred == NULL) {
 214         /* no creds, must be acquire creds request */
 215         if ((ccache->flags & KCM_MASK_KEY_PRESENT) == 0) {
 216             kcm_log(0, "Cannot acquire credentials without a key");
 217             return KRB5_FCC_INTERNAL;
 218         }
 219
 220         event->fire_time = time(NULL); /* right away */
 221         event->action = KCM_EVENT_ACQUIRE_CREDS;
 222     } else if (is_primary_credential_p(context, ccache, newcred)) {
 223         if (newcred->flags.b.renewable) {
 224             event->action = KCM_EVENT_RENEW_CREDS;
 225             ccache->flags |= KCM_FLAGS_RENEWABLE;
 226         } else {
 227             if (ccache->flags & KCM_MASK_KEY_PRESENT)
 228                 event->action = KCM_EVENT_ACQUIRE_CREDS;
 229             else
 230                 event->action = KCM_EVENT_NONE;
 231             ccache->flags &= ~(KCM_FLAGS_RENEWABLE);
 232         }
 233         /* requeue with some slop factor */
 234         event->fire_time = newcred->times.endtime - KCM_EVENT_QUEUE_INTERVAL;
 235     } else {
 236         event->action = KCM_EVENT_NONE;
 237     }
 238
 239     return ret;
 240 }
 241
 242 krb5_error_code
 243 kcm_ccache_enqueue_default(krb5_context context,
 244                            kcm_ccache ccache,
 245                            krb5_creds *newcred)
 246 {
 247     kcm_event event;
 248     krb5_error_code ret;
 249
 250     memset(&event, 0, sizeof(event));
 251     event.ccache = ccache;
 252
 253     ret = kcm_ccache_make_default_event(context, &event, newcred);
 254     if (ret)
 255         return ret;
 256
 257     ret = kcm_enqueue_event_internal(context, &event);
 258     if (ret)
 259         return ret;
 260
 261     return 0;
 262 }
 263
 264 krb5_error_code
 265 kcm_remove_event(krb5_context context,
 266                  kcm_event *event)
 267 {
 268     krb5_error_code ret;
 269     kcm_event **e;
 270     int found = 0;
 271
 272     log_event(event, "removing");
 273
 274     HEIMDAL_MUTEX_lock(&events_mutex);
 275     for (e = &events_head; *e != NULL; e = &(*e)->next) {
 276         if (event == *e) {
 277             *e = event->next;
 278             found++;
 279             break;
 280         }
 281     }
 282
 283     if (!found) {
 284         ret = KRB5_CC_NOTFOUND;
 285         goto out;
 286     }
 287
 288     ret = kcm_remove_event_internal(context, &event);
 289
 290 out:
 291     HEIMDAL_MUTEX_unlock(&events_mutex);
 292
 293     return ret;
 294 }
 295
 296 krb5_error_code
 297 kcm_cleanup_events(krb5_context context,
 298                    kcm_ccache ccache)
 299 {
 300     kcm_event **e;
 301
 302     KCM_ASSERT_VALID(ccache);
 303
 304     HEIMDAL_MUTEX_lock(&events_mutex);
 305
 306     for (e = &events_head; *e != NULL; e = &(*e)->next) {
 307         if ((*e)->valid && (*e)->ccache == ccache) {
 308             kcm_remove_event_internal(context, e);
 309         }
 310         if (*e == NULL)
 311             break;
 312     }
 313
 314     HEIMDAL_MUTEX_unlock(&events_mutex);
 315
 316     return 0;
 317 }
 318
 319 static krb5_error_code
 320 kcm_fire_event(krb5_context context,
 321                kcm_event **e)
 322 {
 323     kcm_event *event;
 324     krb5_error_code ret;
 325     krb5_creds *credp = NULL;
 326     int oneshot = 1;
 327
 328     event = *e;
 329
 330     switch (event->action) {
 331     case KCM_EVENT_ACQUIRE_CREDS:
 332         ret = kcm_ccache_acquire(context, event->ccache, &credp);
 333         oneshot = 0;
 334         break;
 335     case KCM_EVENT_RENEW_CREDS:
 336         ret = kcm_ccache_refresh(context, event->ccache, &credp);
 337         if (ret == KRB5KRB_AP_ERR_TKT_EXPIRED) {
 338             ret = kcm_ccache_acquire(context, event->ccache, &credp);
 339         }
 340         oneshot = 0;
 341         break;
 342     case KCM_EVENT_DESTROY_CREDS:
 343         ret = kcm_ccache_destroy(context, event->ccache->name);
 344         break;
 345     case KCM_EVENT_DESTROY_EMPTY_CACHE:
 346         ret = kcm_ccache_destroy_if_empty(context, event->ccache);
 347         break;
 348     default:
 349         ret = KRB5_FCC_INTERNAL;
 350         break;
 351     }
 352
 353     event->fire_count++;
 354
 355     if (ret) {
 356         /* Reschedule failed event for another time */
 357         event->fire_time += event->backoff_time;
 358         if (event->backoff_time < KCM_EVENT_MAX_BACKOFF_TIME)
 359             event->backoff_time *= 2;
 360
 361         /* Remove it if it would never get executed */
 362         if (event->expire_time &&
 363             event->fire_time > event->expire_time)
 364             kcm_remove_event_internal(context, e);
 365     } else {
 366         if (!oneshot) {
 367             char *cpn;
 368
 369             if (krb5_unparse_name(context, event->ccache->client,
 370                                   &cpn))
 371                 cpn = NULL;
 372
 373             kcm_log(0, "%s credentials in cache %s for principal %s",
 374                     (event->action == KCM_EVENT_ACQUIRE_CREDS) ?
 375                         "Acquired" : "Renewed",
 376                     event->ccache->name,
 377                     (cpn != NULL) ? cpn : "<none>");
 378
 379             if (cpn != NULL)
 380                 free(cpn);
 381
 382             /* Succeeded, but possibly replaced with another event */
 383             ret = kcm_ccache_make_default_event(context, event, credp);
 384             if (ret || event->action == KCM_EVENT_NONE)
 385                 oneshot = 1;
 386             else
 387                 log_event(event, "requeuing");
 388         }
 389         if (oneshot)
 390             kcm_remove_event_internal(context, e);
 391     }
 392
 393     return ret;
 394 }
 395
 396 krb5_error_code
 397 kcm_run_events(krb5_context context, time_t now)
 398 {
 399     krb5_error_code ret;
 400     kcm_event **e;
 401     const char *estr;
 402
 403     HEIMDAL_MUTEX_lock(&events_mutex);
 404
 405     /* Only run event queue every N seconds */
 406     if (now < last_run + KCM_EVENT_QUEUE_INTERVAL) {
 407         HEIMDAL_MUTEX_unlock(&events_mutex);
 408         return 0;
 409     }
 410
 411     /* go through events list, fire and expire */
 412     for (e = &events_head; *e != NULL; e = &(*e)->next) {
 413         if ((*e)->valid == 0)
 414             continue;
 415
 416         if (now >= (*e)->fire_time) {
 417             ret = kcm_fire_event(context, e);
 418             if (ret) {
 419                 estr = krb5_get_error_message(context, ret);
 420                 kcm_log(1, "Could not fire event for cache %s: %s",
 421                         (*e)->ccache->name, estr);
 422                 krb5_free_error_message(context, estr);
 423             }
 424         } else if ((*e)->expire_time && now >= (*e)->expire_time) {
 425             ret = kcm_remove_event_internal(context, e);
 426             if (ret) {
 427                 estr = krb5_get_error_message(context, ret);
 428                 kcm_log(1, "Could not expire event for cache %s: %s",
 429                         (*e)->ccache->name, estr);
 430                 krb5_free_error_message(context, estr);
 431             }
 432         }
 433
 434         if (*e == NULL)
 435             break;
 436     }
 437
 438     last_run = now;
 439
 440     HEIMDAL_MUTEX_unlock(&events_mutex);
 441
 442     return 0;
 443 }
 444