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 "rb_dictionary.h"
  50 #include "authd.h"
  51 #include "provider.h"
  52 #include "notice.h"
  53
  54 rb_dlink_list auth_providers;
  55
  56 /* Clients waiting */
  57 rb_dictionary *auth_clients;
  58
  59 /* Load a provider */
  60 void load_provider(struct auth_provider *provider)
  61 {
  62         if(rb_dlink_list_length(&auth_providers) >= MAX_PROVIDERS)
  63         {
  64                 warn_opers(L_CRIT, "Exceeded maximum level of authd providers (%d max)", MAX_PROVIDERS);
  65                 return;
  66         }
  67
  68         if(provider->opt_handlers != NULL)
  69         {
  70                 struct auth_opts_handler *handler;
  71
  72                 for(handler = provider->opt_handlers; handler->option != NULL; handler++)
  73                         rb_dictionary_add(authd_option_handlers, handler->option, handler);
  74         }
  75
  76         provider->init();
  77         rb_dlinkAdd(provider, &provider->node, &auth_providers);
  78 }
  79
  80 void unload_provider(struct auth_provider *provider)
  81 {
  82         if(provider->opt_handlers != NULL)
  83         {
  84                 struct auth_opts_handler *handler;
  85
  86                 for(handler = provider->opt_handlers; handler->option != NULL; handler++)
  87                         rb_dictionary_delete(authd_option_handlers, handler->option);
  88         }
  89         provider->destroy();
  90         rb_dlinkDelete(&provider->node, &auth_providers);
  91 }
  92
  93 /* Initalise all providers */
  94 void init_providers(void)
  95 {
  96         auth_clients = rb_dictionary_create("pending auth clients", rb_uint32cmp);
  97         load_provider(&rdns_provider);
  98         load_provider(&ident_provider);
  99         load_provider(&blacklist_provider);
 100 }
 101
 102 /* Terminate all providers */
 103 void destroy_providers(void)
 104 {
 105         rb_dlink_node *ptr;
 106         rb_dictionary_iter iter;
 107         struct auth_client *auth;
 108         struct auth_provider *provider;
 109
 110         /* Cancel outstanding connections */
 111         RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
 112         {
 113                 /* TBD - is this the right thing? */
 114                 reject_client(auth, 0, "Authentication system is down... try reconnecting in a few seconds");
 115         }
 116
 117         RB_DLINK_FOREACH(ptr, auth_providers.head)
 118         {
 119                 provider = ptr->data;
 120
 121                 if(provider->destroy)
 122                         provider->destroy();
 123         }
 124 }
 125
 126 /* Cancel outstanding providers for a client */
 127 void cancel_providers(struct auth_client *auth)
 128 {
 129         rb_dlink_node *ptr;
 130         struct auth_provider *provider;
 131
 132         RB_DLINK_FOREACH(ptr, auth_providers.head)
 133         {
 134                 provider = ptr->data;
 135
 136                 if(provider->cancel && is_provider_on(auth, provider->id))
 137                         /* Cancel if required */
 138                         provider->cancel(auth);
 139         }
 140
 141         rb_dictionary_delete(auth_clients, RB_UINT_TO_POINTER(auth->cid));
 142         rb_free(auth);
 143 }
 144
 145 /* Provider is done */
 146 void provider_done(struct auth_client *auth, provider_t id)
 147 {
 148         rb_dlink_node *ptr;
 149         struct auth_provider *provider;
 150
 151         set_provider_off(auth, id);
 152         set_provider_done(auth, id);
 153
 154         if(!auth->providers)
 155         {
 156                 /* No more providers, done */
 157                 accept_client(auth, 0);
 158                 return;
 159         }
 160
 161         RB_DLINK_FOREACH(ptr, auth_providers.head)
 162         {
 163                 provider = ptr->data;
 164
 165                 if(provider->completed && is_provider_on(auth, provider->id))
 166                         /* Notify pending clients who asked for it */
 167                         provider->completed(auth, id);
 168         }
 169 }
 170
 171 /* Reject a client */
 172 void reject_client(struct auth_client *auth, provider_t id, const char *reason)
 173 {
 174         char reject;
 175
 176         switch(id)
 177         {
 178         case PROVIDER_RDNS:
 179                 reject = 'D';
 180                 break;
 181         case PROVIDER_IDENT:
 182                 reject = 'I';
 183                 break;
 184         case PROVIDER_BLACKLIST:
 185                 reject = 'B';
 186                 break;
 187         default:
 188                 reject = 'N';
 189                 break;
 190         }
 191
 192         /* We send back username and hostname in case ircd wants to overrule our decision.
 193          * In the future this may not be the case.
 194          * --Elizafox
 195          */
 196         rb_helper_write(authd_helper, "R %x %c %s %s :%s", auth->cid, reject, auth->username, auth->hostname, reason);
 197
 198         set_provider_off(auth, id);
 199         cancel_providers(auth);
 200 }
 201
 202 /* Accept a client, cancel outstanding providers if any */
 203 void accept_client(struct auth_client *auth, provider_t id)
 204 {
 205         uint32_t cid = auth->cid;
 206
 207         rb_helper_write(authd_helper, "A %x %s %s", auth->cid, auth->username, auth->hostname);
 208
 209         set_provider_off(auth, id);
 210         cancel_providers(auth);
 211 }
 212
 213 /* Begin authenticating user */
 214 static void start_auth(const char *cid, const char *l_ip, const char *l_port, const char *c_ip, const char *c_port)
 215 {
 216         struct auth_provider *provider;
 217         struct auth_client *auth = rb_malloc(sizeof(struct auth_client));
 218         long lcid = strtol(cid, NULL, 16);
 219         rb_dlink_node *ptr;
 220
 221         if(lcid >= UINT32_MAX)
 222                 return;
 223
 224         auth->cid = (uint32_t)lcid;
 225
 226         rb_strlcpy(auth->l_ip, l_ip, sizeof(auth->l_ip));
 227         auth->l_port = (uint16_t)atoi(l_port);  /* should be safe */
 228         (void) rb_inet_pton_sock(l_ip, (struct sockaddr *)&auth->l_addr);
 229
 230         rb_strlcpy(auth->c_ip, c_ip, sizeof(auth->c_ip));
 231         auth->c_port = (uint16_t)atoi(c_port);
 232         (void) rb_inet_pton_sock(c_ip, (struct sockaddr *)&auth->c_addr);
 233
 234 #ifdef RB_IPV6
 235         if(GET_SS_FAMILY(&auth->l_addr) == AF_INET6)
 236                 ((struct sockaddr_in6 *)&auth->l_addr)->sin6_port = htons(auth->l_port);
 237         else
 238 #endif
 239                 ((struct sockaddr_in *)&auth->l_addr)->sin_port = htons(auth->l_port);
 240
 241 #ifdef RB_IPV6
 242         if(GET_SS_FAMILY(&auth->c_addr) == AF_INET6)
 243                 ((struct sockaddr_in6 *)&auth->c_addr)->sin6_port = htons(auth->c_port);
 244         else
 245 #endif
 246                 ((struct sockaddr_in *)&auth->c_addr)->sin_port = htons(auth->c_port);
 247
 248         memset(auth->data, 0, sizeof(auth->data));
 249
 250         rb_dictionary_add(auth_clients, RB_UINT_TO_POINTER(auth->cid), auth);
 251
 252         RB_DLINK_FOREACH(ptr, auth_providers.head)
 253         {
 254                 provider = ptr->data;
 255
 256                 /* Execute providers */
 257                 if(!provider->start(auth))
 258                 {
 259                         /* Rejected immediately */
 260                         cancel_providers(auth);
 261                         return;
 262                 }
 263         }
 264
 265         /* If no providers are running, accept the client */
 266         if(!auth->providers)
 267                 accept_client(auth, 0);
 268 }
 269
 270 /* Callback for the initiation */
 271 void handle_new_connection(int parc, char *parv[])
 272 {
 273         if(parc < 6)
 274         {
 275                 warn_opers(L_CRIT, "BUG: received too few params for new connection (6 expected, got %d)", parc);
 276                 return;
 277         }
 278
 279         start_auth(parv[1], parv[2], parv[3], parv[4], parv[5]);
 280 }