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 }
 100
 101 /* Terminate all providers */
 102 void destroy_providers(void)
 103 {
 104         rb_dlink_node *ptr;
 105         rb_dictionary_iter iter;
 106         struct auth_client *auth;
 107         struct auth_provider *provider;
 108
 109         /* Cancel outstanding connections */
 110         RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
 111         {
 112                 /* TBD - is this the right thing? */
 113                 reject_client(auth, 0, "Authentication system is down... try reconnecting in a few seconds");
 114         }
 115
 116         RB_DLINK_FOREACH(ptr, auth_providers.head)
 117         {
 118                 provider = ptr->data;
 119
 120                 if(provider->destroy)
 121                         provider->destroy();
 122         }
 123 }
 124
 125 /* Cancel outstanding providers for a client */
 126 void cancel_providers(struct auth_client *auth)
 127 {
 128         rb_dlink_node *ptr;
 129         struct auth_provider *provider;
 130
 131         RB_DLINK_FOREACH(ptr, auth_providers.head)
 132         {
 133                 provider = ptr->data;
 134
 135                 if(provider->cancel && is_provider_on(auth, provider->id))
 136                         /* Cancel if required */
 137                         provider->cancel(auth);
 138         }
 139
 140         rb_dictionary_delete(auth_clients, RB_UINT_TO_POINTER(auth->cid));
 141         rb_free(auth);
 142 }
 143
 144 /* Provider is done */
 145 void provider_done(struct auth_client *auth, provider_t id)
 146 {
 147         rb_dlink_node *ptr;
 148         struct auth_provider *provider;
 149
 150         set_provider_off(auth, id);
 151         set_provider_done(auth, id);
 152
 153         if(!auth->providers)
 154         {
 155                 /* No more providers, done */
 156                 accept_client(auth, 0);
 157                 return;
 158         }
 159
 160         RB_DLINK_FOREACH(ptr, auth_providers.head)
 161         {
 162                 provider = ptr->data;
 163
 164                 if(provider->completed && is_provider_on(auth, provider->id))
 165                         /* Notify pending clients who asked for it */
 166                         provider->completed(auth, id);
 167         }
 168 }
 169
 170 /* Reject a client */
 171 void reject_client(struct auth_client *auth, provider_t id, const char *reason)
 172 {
 173         char reject;
 174
 175         switch(id)
 176         {
 177         case PROVIDER_RDNS:
 178                 reject = 'D';
 179                 break;
 180         case PROVIDER_IDENT:
 181                 reject = 'I';
 182                 break;
 183         case PROVIDER_BLACKLIST:
 184                 reject = 'B';
 185                 break;
 186         default:
 187                 reject = 'N';
 188                 break;
 189         }
 190
 191         /* We send back username and hostname in case ircd wants to overrule our decision.
 192          * In the future this may not be the case.
 193          * --Elizafox
 194          */
 195         rb_helper_write(authd_helper, "R %x %c %s %s :%s", auth->cid, reject, auth->username, auth->hostname, reason);
 196
 197         set_provider_off(auth, id);
 198         cancel_providers(auth);
 199 }
 200
 201 /* Accept a client, cancel outstanding providers if any */
 202 void accept_client(struct auth_client *auth, provider_t id)
 203 {
 204         uint32_t cid = auth->cid;
 205
 206         rb_helper_write(authd_helper, "A %x %s %s", auth->cid, auth->username, auth->hostname);
 207
 208         set_provider_off(auth, id);
 209         cancel_providers(auth);
 210 }
 211
 212 /* Begin authenticating user */
 213 static void start_auth(const char *cid, const char *l_ip, const char *l_port, const char *c_ip, const char *c_port)
 214 {
 215         struct auth_provider *provider;
 216         struct auth_client *auth = rb_malloc(sizeof(struct auth_client));
 217         long lcid = strtol(cid, NULL, 16);
 218         rb_dlink_node *ptr;
 219
 220         if(lcid >= UINT32_MAX)
 221                 return;
 222
 223         auth->cid = (uint32_t)lcid;
 224
 225         rb_strlcpy(auth->l_ip, l_ip, sizeof(auth->l_ip));
 226         auth->l_port = (uint16_t)atoi(l_port);  /* should be safe */
 227         (void) rb_inet_pton_sock(l_ip, (struct sockaddr *)&auth->l_addr);
 228
 229         rb_strlcpy(auth->c_ip, c_ip, sizeof(auth->c_ip));
 230         auth->c_port = (uint16_t)atoi(c_port);
 231         (void) rb_inet_pton_sock(c_ip, (struct sockaddr *)&auth->c_addr);
 232
 233 #ifdef RB_IPV6
 234         if(GET_SS_FAMILY(&auth->l_addr) == AF_INET6)
 235                 ((struct sockaddr_in6 *)&auth->l_addr)->sin6_port = htons(auth->l_port);
 236         else
 237 #endif
 238                 ((struct sockaddr_in *)&auth->l_addr)->sin_port = htons(auth->l_port);
 239
 240 #ifdef RB_IPV6
 241         if(GET_SS_FAMILY(&auth->c_addr) == AF_INET6)
 242                 ((struct sockaddr_in6 *)&auth->c_addr)->sin6_port = htons(auth->c_port);
 243         else
 244 #endif
 245                 ((struct sockaddr_in *)&auth->c_addr)->sin_port = htons(auth->c_port);
 246
 247         rb_dictionary_add(auth_clients, RB_UINT_TO_POINTER(auth->cid), auth);
 248
 249         RB_DLINK_FOREACH(ptr, auth_providers.head)
 250         {
 251                 provider = ptr->data;
 252
 253                 /* Execute providers */
 254                 if(!provider->start(auth))
 255                 {
 256                         /* Rejected immediately */
 257                         cancel_providers(auth);
 258                         return;
 259                 }
 260         }
 261
 262         /* If no providers are running, accept the client */
 263         if(!auth->providers)
 264                 accept_client(auth, 0);
 265 }
 266
 267 /* Callback for the initiation */
 268 void handle_new_connection(int parc, char *parv[])
 269 {
 270         if(parc < 7)
 271         {
 272                 warn_opers(L_CRIT, "BUG: received too few params for new connection (7 expected, got %d)", parc);
 273                 return;
 274         }
 275
 276         start_auth(parv[1], parv[2], parv[3], parv[4], parv[5]);
 277 }