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 /* So the basic design here is to have "authentication providers" that do
  22  * things like query ident and blacklists and even open proxies.
  23  *
  24  * Providers are registered statically in the struct auth_providers array. You will
  25  * probably want to add an item to the provider_t enum also.
  26  *
  27  * Providers can either return failure immediately, immediate acceptance, or
  28  * do work in the background (calling set_provider to signal this).
  29  *
  30  * It is up to providers to keep their own state on clients if they need to.
  31  *
  32  * All providers must implement at a minimum a perform_provider function. You
  33  * don't have to implement the others if you don't need them.
  34  *
  35  * Providers may kick clients off by rejecting them. Upon rejection, all
  36  * providers are cancelled. They can also unconditionally accept them.
  37  *
  38  * When a provider is done and is neutral on accepting/rejecting a client, it
  39  * should call provider_done. Do NOT call this if you have accepted or rejected
  40  * the client.
  41  *
  42  * --Elizafox, 9 March 2016
  43  */
  44
  45 #include "authd.h"
  46 #include "provider.h"
  47
  48 rb_dlink_list auth_providers;
  49
  50 /* Clients waiting */
  51 struct auth_client auth_clients[MAX_CLIENTS];
  52
  53 /* Load a provider */
  54 void load_provider(struct auth_provider *provider)
  55 {
  56         provider->init();
  57         rb_dlinkAdd(provider, &provider->node, &auth_providers);
  58 }
  59
  60 void unload_provider(struct auth_provider *provider)
  61 {
  62         provider->destroy();
  63         rb_dlinkDelete(&provider->node, &auth_providers);
  64 }
  65
  66 /* Initalise all providers */
  67 void init_providers(void)
  68 {
  69         rb_dlink_node *ptr;
  70         struct auth_provider *provider;
  71
  72         RB_DLINK_FOREACH(ptr, auth_providers.head)
  73         {
  74                 provider = ptr->data;
  75
  76                 if(provider->init && !provider->init())
  77                         /* Provider failed to init, time to go */
  78                         exit(1);
  79         }
  80 }
  81
  82 /* Terminate all providers */
  83 void destroy_providers(void)
  84 {
  85         rb_dlink_node *ptr;
  86         struct auth_provider *provider;
  87
  88         /* Cancel outstanding connections */
  89         for (size_t i = 0; i < MAX_CLIENTS; i++)
  90         {
  91                 if(auth_clients[i].cid)
  92                 {
  93                         /* TBD - is this the right thing?
  94                          * (NOTE - this error message is designed for morons) */
  95                         reject_client(&auth_clients[i], 0,
  96                                         "IRC server reloading... try reconnecting in a few seconds");
  97                 }
  98         }
  99
 100         RB_DLINK_FOREACH(ptr, auth_providers.head)
 101         {
 102                 provider = ptr->data;
 103
 104                 if(provider->destroy)
 105                         provider->destroy();
 106         }
 107 }
 108
 109 /* Cancel outstanding providers for a client */
 110 void cancel_providers(struct auth_client *auth)
 111 {
 112         rb_dlink_node *ptr;
 113         struct auth_provider *provider;
 114
 115         RB_DLINK_FOREACH(ptr, auth_providers.head)
 116         {
 117                 provider = ptr->data;
 118
 119                 if(provider->cancel && is_provider(auth, provider->id))
 120                         /* Cancel if required */
 121                         provider->cancel(auth);
 122         }
 123 }
 124
 125 /* Provider is done */
 126 void provider_done(struct auth_client *auth, provider_t id)
 127 {
 128         rb_dlink_node *ptr;
 129         struct auth_provider *provider;
 130
 131         unset_provider(auth, id);
 132
 133         if(!auth->providers)
 134         {
 135                 /* No more providers, done */
 136                 accept_client(auth, 0);
 137                 return;
 138         }
 139
 140         RB_DLINK_FOREACH(ptr, auth_providers.head)
 141         {
 142                 provider = ptr->data;
 143
 144                 if(provider->completed && is_provider(auth, provider->id))
 145                         /* Notify pending clients who asked for it */
 146                         provider->completed(auth, id);
 147         }
 148 }
 149
 150 /* Reject a client, cancel outstanding providers if any */
 151 void reject_client(struct auth_client *auth, provider_t id, const char *reason)
 152 {
 153         uint16_t cid = auth->cid;
 154
 155         rb_helper_write(authd_helper, "R %x :%s", auth->cid, reason);
 156
 157         unset_provider(auth, id);
 158
 159         if(auth->providers)
 160                 cancel_providers(auth);
 161
 162         memset(&auth_clients[cid], 0, sizeof(struct auth_client));
 163 }
 164
 165 /* Accept a client, cancel outstanding providers if any */
 166 void accept_client(struct auth_client *auth, provider_t id)
 167 {
 168         uint16_t cid = auth->cid;
 169
 170         rb_helper_write(authd_helper, "A %x %s %s", auth->cid, auth->username, auth->hostname);
 171
 172         unset_provider(auth, id);
 173
 174         if(auth->providers)
 175                 cancel_providers(auth);
 176
 177         memset(&auth_clients[cid], 0, sizeof(struct auth_client));
 178 }
 179
 180 /* Send a notice to a client */
 181 void notice_client(struct auth_client *auth, const char *notice)
 182 {
 183         rb_helper_write(authd_helper, "N %x :%s", auth->cid, notice);
 184 }
 185
 186 /* Begin authenticating user */
 187 void start_auth(const char *cid, const char *l_ip, const char *l_port, const char *c_ip, const char *c_port)
 188 {
 189         rb_dlink_node *ptr;
 190         struct auth_provider *provider;
 191         struct auth_client *auth;
 192         long lcid = strtol(cid, NULL, 16);
 193
 194         if(lcid >= MAX_CLIENTS)
 195                 return;
 196
 197         auth = &auth_clients[lcid];
 198         if(auth->cid != 0)
 199                 /* Shouldn't get here */
 200                 return;
 201
 202         auth->cid = (uint16_t)lcid;
 203
 204         rb_strlcpy(auth->l_ip, l_ip, sizeof(auth->l_ip));
 205         auth->l_port = (uint16_t)atoi(l_port); /* Safe cast, port shouldn't exceed 16 bits  */
 206
 207         rb_strlcpy(auth->c_ip, c_ip, sizeof(auth->c_ip));
 208         auth->c_port = (uint16_t)atoi(c_port);
 209
 210         RB_DLINK_FOREACH(ptr, auth_providers.head)
 211         {
 212                 provider = ptr->data;
 213
 214                 /* Execute providers */
 215                 if(!provider->start(auth))
 216                 {
 217                         /* Rejected immediately */
 218                         cancel_providers(auth);
 219                         return;
 220                 }
 221         }
 222
 223         /* If no providers are running, accept the client */
 224         if(!auth->providers)
 225                 accept_client(auth, 0);
 226 }
 227
 228 /* Callback for the initiation */
 229 void handle_new_connection(int parc, char *parv[])
 230 {
 231         if(parc < 5)
 232                 return;
 233
 234         start_auth(parv[1], parv[2], parv[3], parv[4], parv[5]);
 235 }