authd/provider.c

   1 /* authd/provider.c - authentication provider framework
   2  * Copyright (c) 2016 Elizabeth Myers <elizabeth@interlinked.me>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice is present in all copies.
   7  *
   8  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   9  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  10  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  11  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  12  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  13  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  14  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  15  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  16  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  17  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  18  * POSSIBILITY OF SUCH DAMAGE.
  19  */
  20
  21 /* The basic design here is to have "authentication providers" that do things
  22  * like query ident and blacklists and even open proxies.
  23  *
  24  * Providers are registered in the auth_providers linked list. It is planned to
  25  * use a bitmap to store provider ID's later.
  26  *
  27  * Providers can either return failure immediately, immediate acceptance, or do
  28  * work in the background (calling set_provider to signal this).
  29  *
  30  * Provider-specific data for each client can be kept in an index of the data
  31  * struct member (using the provider's ID).
  32  *
  33  * All providers must implement at a minimum a perform_provider function. You
  34  * don't have to implement the others if you don't need them.
  35  *
  36  * Providers may kick clients off by rejecting them. Upon rejection, all
  37  * providers are cancelled. They can also unconditionally accept them.
  38  *
  39  * When a provider is done and is neutral on accepting/rejecting a client, it
  40  * should call provider_done. Do NOT call this if you have accepted or rejected
  41  * the client.
  42  *
  43  * Eventually, stuff like *:line handling will be moved here, but that means we
  44  * have to talk to bandb directly first.
  45  *
  46  * --Elizafox, 9 March 2016
  47  */
  48
  49 #include "stdinc.h"
  50 #include "rb_dictionary.h"
  51 #include "authd.h"
  52 #include "provider.h"
  53 #include "notice.h"
  54
  55 static EVH provider_timeout_event;
  56
  57 rb_dictionary *auth_clients;
  58 rb_dictionary *auth_providers;  /* Referenced by name */
  59
  60 static rb_dlink_list free_pids;
  61 static uint32_t pid;
  62 static struct ev_entry *timeout_ev;
  63
  64 /* Initalise all providers */
  65 void
  66 init_providers(void)
  67 {
  68         auth_clients = rb_dictionary_create("pending auth clients", rb_uint32cmp);
  69         auth_providers = rb_dictionary_create("auth providers", strcmp);
  70         timeout_ev = rb_event_addish("provider_timeout_event", provider_timeout_event, NULL, 1);
  71
  72         load_provider(&rdns_provider);
  73         load_provider(&ident_provider);
  74         load_provider(&blacklist_provider);
  75         load_provider(&opm_provider);
  76 }
  77
  78 /* Terminate all providers */
  79 void
  80 destroy_providers(void)
  81 {
  82         rb_dlink_node *ptr;
  83         rb_dictionary_iter iter;
  84         struct auth_client *auth;
  85         struct auth_provider *provider;
  86
  87         /* Cancel outstanding connections */
  88         RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
  89         {
  90                 /* TBD - is this the right thing? */
  91                 reject_client(auth, UINT32_MAX, "destroy",
  92                         "Authentication system is down... try reconnecting in a few seconds");
  93         }
  94
  95         RB_DICTIONARY_FOREACH(provider, &iter, auth_providers)
  96         {
  97                 if(provider->destroy)
  98                         provider->destroy();
  99         }
 100
 101         rb_dictionary_destroy(auth_clients, NULL, NULL);
 102         rb_dictionary_destroy(auth_providers, NULL, NULL);
 103         rb_event_delete(timeout_ev);
 104 }
 105
 106 /* Load a provider */
 107 void
 108 load_provider(struct auth_provider *provider)
 109 {
 110         /* Assign a PID */
 111         if(rb_dlink_list_length(&free_pids) > 0)
 112         {
 113                 /* use the free list */
 114                 provider->id = RB_POINTER_TO_UINT(free_pids.head->data);
 115                 rb_dlinkDestroy(free_pids.head, &free_pids);
 116         }
 117         else
 118         {
 119                 if(pid == UINT32_MAX)
 120                 {
 121                         /* If this happens, well, I don't know what to say. Probably a bug.
 122                          * In any case, UINT32_MAX is a special sentinel. */
 123                         warn_opers(L_WARN, "Cannot load additional provider, max reached!");
 124                         return;
 125                 }
 126
 127                 provider->id = pid++;
 128         }
 129
 130         if(provider->opt_handlers != NULL)
 131         {
 132                 struct auth_opts_handler *handler;
 133
 134                 for(handler = provider->opt_handlers; handler->option != NULL; handler++)
 135                         rb_dictionary_add(authd_option_handlers, handler->option, handler);
 136         }
 137
 138         if(provider->stats_handler.letter != '\0')
 139                 authd_stat_handlers[(unsigned char)provider->stats_handler.letter] = provider->stats_handler.handler;
 140
 141         if(provider->init != NULL)
 142                 provider->init();
 143
 144         rb_dictionary_add(auth_providers, provider->name, provider);
 145 }
 146
 147 void
 148 unload_provider(struct auth_provider *provider)
 149 {
 150         if(provider->opt_handlers != NULL)
 151         {
 152                 struct auth_opts_handler *handler;
 153
 154                 for(handler = provider->opt_handlers; handler->option != NULL; handler++)
 155                         rb_dictionary_delete(authd_option_handlers, handler->option);
 156         }
 157
 158         if(provider->stats_handler.letter != '\0')
 159                 authd_stat_handlers[(unsigned char)provider->stats_handler.letter] = NULL;
 160
 161         if(provider->destroy != NULL)
 162                 provider->destroy();
 163
 164         rb_dictionary_delete(auth_providers, provider->name);
 165
 166         /* Reclaim ID */
 167         rb_dlinkAddAlloc(RB_UINT_TO_POINTER(provider->id), &free_pids);
 168 }
 169
 170
 171 /* Cancel outstanding providers for a client (if any) and free the auth instance
 172  * WARNING: do not use auth instance after calling! */
 173 void
 174 cancel_providers(struct auth_client *auth)
 175 {
 176         if(auth->refcount > 0)
 177         {
 178                 rb_dictionary_iter iter;
 179                 struct auth_provider *provider;
 180
 181                 RB_DICTIONARY_FOREACH(provider, &iter, auth_providers)
 182                 {
 183                         if(provider->cancel != NULL && is_provider_running(auth, provider->id))
 184                                 /* Cancel if required */
 185                                 provider->cancel(auth);
 186                 }
 187         }
 188
 189         rb_dictionary_delete(auth_clients, RB_UINT_TO_POINTER(auth->cid));
 190         rb_free(auth->data);
 191         rb_free(auth);
 192 }
 193
 194 /* Provider is done
 195  * WARNING: do not use auth instance after calling! */
 196 void
 197 provider_done(struct auth_client *auth, uint32_t id)
 198 {
 199         rb_dictionary_iter iter;
 200         struct auth_provider *provider;
 201
 202         lrb_assert(is_provider_running(auth, id));
 203         lrb_assert(id != UINT32_MAX);
 204         lrb_assert(id <= pid);
 205
 206         set_provider_done(auth, id);
 207
 208         if(auth->refcount == 0 && !auth->providers_starting)
 209         {
 210                 /* All done */
 211                 accept_client(auth, id);
 212                 return;
 213         }
 214
 215         RB_DICTIONARY_FOREACH(provider, &iter, auth_providers)
 216         {
 217                 if(provider->completed != NULL && is_provider_running(auth, provider->id))
 218                         /* Notify pending clients who asked for it */
 219                         provider->completed(auth, id);
 220         }
 221 }
 222
 223 /* Reject a client and cancel any outstanding providers
 224  * WARNING: do not use auth instance after calling! */
 225 void
 226 reject_client(struct auth_client *auth, uint32_t id, const char *data, const char *fmt, ...)
 227 {
 228         unsigned int refcount = auth->refcount;
 229         char buf[BUFSIZE];
 230         va_list args;
 231
 232         va_start(args, fmt);
 233         vsnprintf(buf, sizeof(buf), fmt, args);
 234         va_end(args);
 235
 236         /* We send back username and hostname in case ircd wants to overrule our decision.
 237          * In the future this may not be the case.
 238          * --Elizafox
 239          */
 240         rb_helper_write(authd_helper, "R %x %c %s %s %s :%s",
 241                 auth->cid, auth->data[id].provider->letter,
 242                 auth->username, auth->hostname,
 243                 data == NULL ? "*" : data, buf);
 244
 245         if(id != UINT32_MAX)
 246                 set_provider_done(auth, id);
 247
 248         cancel_providers(auth);
 249 }
 250
 251 /* Accept a client and cancel outstanding providers if any
 252  * WARNING: do not use auth instance after calling! */
 253 void
 254 accept_client(struct auth_client *auth, uint32_t id)
 255 {
 256         unsigned int refcount = auth->refcount;
 257
 258         rb_helper_write(authd_helper, "A %x %s %s", auth->cid, auth->username, auth->hostname);
 259
 260         if(id != UINT32_MAX)
 261                 set_provider_done(auth, id);
 262
 263         cancel_providers(auth);
 264 }
 265
 266 /* Begin authenticating user */
 267 static void
 268 start_auth(const char *cid, const char *l_ip, const char *l_port, const char *c_ip, const char *c_port)
 269 {
 270         struct auth_provider *provider;
 271         struct auth_client *auth = rb_malloc(sizeof(struct auth_client));
 272         long lcid = strtol(cid, NULL, 16);
 273         rb_dictionary_iter iter;
 274
 275         if(lcid >= UINT32_MAX)
 276                 return;
 277
 278         auth->cid = (uint32_t)lcid;
 279
 280         if(rb_dictionary_find(auth_clients, RB_UINT_TO_POINTER(auth->cid)) == NULL)
 281                 rb_dictionary_add(auth_clients, RB_UINT_TO_POINTER(auth->cid), auth);
 282         else
 283         {
 284                 warn_opers(L_CRIT, "provider: duplicate client added via start_auth: %x", auth->cid);
 285                 exit(EX_PROVIDER_ERROR);
 286         }
 287
 288         rb_strlcpy(auth->l_ip, l_ip, sizeof(auth->l_ip));
 289         auth->l_port = (uint16_t)atoi(l_port);  /* should be safe */
 290         (void) rb_inet_pton_sock(l_ip, (struct sockaddr *)&auth->l_addr);
 291         SET_SS_PORT(&auth->l_addr, htons(auth->l_port));
 292
 293         rb_strlcpy(auth->c_ip, c_ip, sizeof(auth->c_ip));
 294         auth->c_port = (uint16_t)atoi(c_port);
 295         (void) rb_inet_pton_sock(c_ip, (struct sockaddr *)&auth->c_addr);
 296         SET_SS_PORT(&auth->c_addr, htons(auth->c_port));
 297
 298         rb_strlcpy(auth->hostname, "*", sizeof(auth->hostname));
 299         rb_strlcpy(auth->username, "*", sizeof(auth->username));
 300
 301         auth->data = rb_malloc(rb_dictionary_size(auth_providers) *
 302                         sizeof(struct auth_client_data));
 303
 304         auth->providers_starting = true;
 305         RB_DICTIONARY_FOREACH(provider, &iter, auth_providers)
 306         {
 307                 auth->data[provider->id].provider = provider;
 308
 309                 lrb_assert(provider->start != NULL);
 310
 311                 /* Execute providers */
 312                 if(!provider->start(auth))
 313                         /* Rejected immediately */
 314                         return;
 315         }
 316         auth->providers_starting = false;
 317
 318         /* If no providers are running, accept the client */
 319         if(auth->refcount == 0)
 320                 accept_client(auth, UINT32_MAX);
 321 }
 322
 323 /* Callback for the initiation */
 324 void
 325 handle_new_connection(int parc, char *parv[])
 326 {
 327         if(parc < 6)
 328         {
 329                 warn_opers(L_CRIT, "provider: received too few params for new connection (6 expected, got %d)", parc);
 330                 exit(EX_PROVIDER_ERROR);
 331         }
 332
 333         start_auth(parv[1], parv[2], parv[3], parv[4], parv[5]);
 334 }
 335
 336 void
 337 handle_cancel_connection(int parc, char *parv[])
 338 {
 339         struct auth_client *auth;
 340         long lcid;
 341
 342         if(parc < 2)
 343         {
 344                 warn_opers(L_CRIT, "provider: received too few params for new connection (2 expected, got %d)", parc);
 345                 exit(EX_PROVIDER_ERROR);
 346         }
 347
 348         if((lcid = strtol(parv[1], NULL, 16)) > UINT32_MAX)
 349         {
 350                 warn_opers(L_CRIT, "provider: got a request to cancel a connection that can't exist: %lx", lcid);
 351                 exit(EX_PROVIDER_ERROR);
 352         }
 353
 354         if((auth = rb_dictionary_retrieve(auth_clients, RB_UINT_TO_POINTER((uint32_t)lcid))) == NULL)
 355         {
 356                 /* This could happen as a race if we've accepted/rejected but they cancel, so don't die here.
 357                  * --Elizafox */
 358                 return;
 359         }
 360
 361         cancel_providers(auth);
 362 }
 363
 364 static void
 365 provider_timeout_event(void *notused __unused)
 366 {
 367         struct auth_client *auth;
 368         rb_dictionary_iter iter;
 369         const time_t curtime = rb_current_time();
 370
 371         RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
 372         {
 373                 rb_dictionary_iter iter2;
 374                 struct auth_provider *provider;
 375
 376                 RB_DICTIONARY_FOREACH(provider, &iter2, auth_providers)
 377                 {
 378                         const time_t timeout = get_provider_timeout(auth, provider->id);
 379
 380                         if(is_provider_running(auth, provider->id) && provider->timeout != NULL &&
 381                                 timeout > 0 && timeout < curtime)
 382                         {
 383                                 provider->timeout(auth);
 384                         }
 385                 }
 386         }
 387 }