modules/m_sasl.c

   1 /* modules/m_sasl.c
   2  *   Copyright (C) 2006 Michael Tharp <gxti@partiallystapled.com>
   3  *   Copyright (C) 2006 charybdis development team
   4  *   Copyright (C) 2016 ChatLounge IRC Network Development Team
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are
   8  * met:
   9  *
  10  * 1.Redistributions of source code must retain the above copyright notice,
  11  *   this list of conditions and the following disclaimer.
  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  * 3.The name of the author may not be used to endorse or promote products
  16  *   derived from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  20  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  22  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  24  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  26  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  27  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28  * POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include "stdinc.h"
  32
  33 #include "client.h"
  34 #include "hash.h"
  35 #include "send.h"
  36 #include "msg.h"
  37 #include "modules.h"
  38 #include "numeric.h"
  39 #include "reject.h"
  40 #include "s_serv.h"
  41 #include "s_stats.h"
  42 #include "string.h"
  43 #include "s_newconf.h"
  44 #include "s_conf.h"
  45
  46 static const char sasl_desc[] = "Provides SASL authentication support";
  47
  48 static void m_authenticate(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
  49 static void me_sasl(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
  50 static void me_mechlist(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
  51
  52 static void abort_sasl(struct Client *);
  53 static void abort_sasl_exit(hook_data_client_exit *);
  54
  55 static void advertise_sasl_cap(bool);
  56 static void advertise_sasl_new(struct Client *);
  57 static void advertise_sasl_exit(void *);
  58 static void advertise_sasl_config(void *);
  59
  60 static unsigned int CLICAP_SASL = 0;
  61 static char mechlist_buf[BUFSIZE];
  62 static bool sasl_agent_present = false;
  63
  64 struct Message authenticate_msgtab = {
  65         "AUTHENTICATE", 0, 0, 0, 0,
  66         {{m_authenticate, 2}, {m_authenticate, 2}, mg_ignore, mg_ignore, mg_ignore, {m_authenticate, 2}}
  67 };
  68 struct Message sasl_msgtab = {
  69         "SASL", 0, 0, 0, 0,
  70         {mg_ignore, mg_ignore, mg_ignore, mg_ignore, {me_sasl, 5}, mg_ignore}
  71 };
  72 struct Message mechlist_msgtab = {
  73         "MECHLIST", 0, 0, 0, 0,
  74         {mg_ignore, mg_ignore, mg_ignore, mg_ignore, {me_mechlist, 2}, mg_ignore}
  75 };
  76
  77 mapi_clist_av1 sasl_clist[] = {
  78         &authenticate_msgtab, &sasl_msgtab, &mechlist_msgtab, NULL
  79 };
  80 mapi_hfn_list_av1 sasl_hfnlist[] = {
  81         { "new_local_user",     (hookfn) abort_sasl },
  82         { "client_exit",        (hookfn) abort_sasl_exit },
  83         { "new_remote_user",    (hookfn) advertise_sasl_new },
  84         { "after_client_exit",  (hookfn) advertise_sasl_exit },
  85         { "conf_read_end",      (hookfn) advertise_sasl_config },
  86         { NULL, NULL }
  87 };
  88
  89 static bool
  90 sasl_visible(struct Client *ignored)
  91 {
  92         struct Client *agent_p = NULL;
  93
  94         if (ConfigFileEntry.sasl_service)
  95                 agent_p = find_named_client(ConfigFileEntry.sasl_service);
  96
  97         return agent_p != NULL && IsService(agent_p);
  98 }
  99
 100 static const char *
 101 sasl_data(struct Client *client_p)
 102 {
 103         return *mechlist_buf != 0 ? mechlist_buf : NULL;
 104 }
 105
 106 static struct ClientCapability capdata_sasl = {
 107         .visible = sasl_visible,
 108         .data = sasl_data,
 109         .flags = CLICAP_FLAGS_STICKY,
 110 };
 111
 112 static int
 113 _modinit(void)
 114 {
 115         memset(mechlist_buf, 0, sizeof mechlist_buf);
 116         sasl_agent_present = false;
 117
 118         CLICAP_SASL = capability_put(cli_capindex, "sasl", &capdata_sasl);
 119         advertise_sasl_config(NULL);
 120         return 0;
 121 }
 122
 123 static void
 124 _moddeinit(void)
 125 {
 126         advertise_sasl_cap(false);
 127         capability_orphan(cli_capindex, "sasl");
 128 }
 129
 130 DECLARE_MODULE_AV2(sasl, _modinit, _moddeinit, sasl_clist, NULL, sasl_hfnlist, NULL, NULL, sasl_desc);
 131
 132 static void
 133 m_authenticate(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p,
 134         int parc, const char *parv[])
 135 {
 136         struct Client *agent_p = NULL;
 137         struct Client *saslserv_p = NULL;
 138
 139         /* They really should use CAP for their own sake. */
 140         if(!IsCapable(source_p, CLICAP_SASL))
 141                 return;
 142
 143         if(source_p->localClient->sasl_next_retry > rb_current_time())
 144         {
 145                 sendto_one(source_p, form_str(RPL_LOAD2HI), me.name, EmptyString(source_p->name) ? "*" : source_p->name, msgbuf_p->cmd);
 146                 return;
 147         }
 148
 149         if (strlen(client_p->id) == 3 || (source_p->preClient && !EmptyString(source_p->preClient->id)))
 150         {
 151                 exit_client(client_p, client_p, client_p, "Mixing client and server protocol");
 152                 return;
 153         }
 154
 155         if (*parv[1] == ':' || strchr(parv[1], ' '))
 156         {
 157                 exit_client(client_p, client_p, client_p, "Malformed AUTHENTICATE");
 158                 return;
 159         }
 160
 161         saslserv_p = find_named_client(ConfigFileEntry.sasl_service);
 162         if(saslserv_p == NULL || !IsService(saslserv_p))
 163         {
 164                 sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
 165                 return;
 166         }
 167
 168         if(source_p->localClient->sasl_complete)
 169         {
 170                 *source_p->localClient->sasl_agent = '\0';
 171                 source_p->localClient->sasl_complete = 0;
 172         }
 173
 174         if(strlen(parv[1]) > 400)
 175         {
 176                 sendto_one(source_p, form_str(ERR_SASLTOOLONG), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
 177                 return;
 178         }
 179
 180         if(!*source_p->id)
 181         {
 182                 /* Allocate a UID. */
 183                 rb_strlcpy(source_p->id, generate_uid(), sizeof(source_p->id));
 184                 add_to_id_hash(source_p->id, source_p);
 185         }
 186
 187         if(*source_p->localClient->sasl_agent)
 188                 agent_p = find_id(source_p->localClient->sasl_agent);
 189
 190         if(agent_p == NULL)
 191         {
 192                 if (!strcmp(parv[1], "*"))
 193                 {
 194                         sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
 195                         source_p->localClient->sasl_out = 0;
 196                         return;
 197                 }
 198
 199                 sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s H %s %s %c",
 200                                         me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id,
 201                                         source_p->host, source_p->sockhost,
 202                                         IsSSL(source_p) ? 'S' : 'P');
 203
 204                 if (source_p->certfp != NULL)
 205                         sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s S %s %s",
 206                                                 me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id,
 207                                                 parv[1], source_p->certfp);
 208                 else
 209                         sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s S %s",
 210                                                 me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id,
 211                                                 parv[1]);
 212
 213                 rb_strlcpy(source_p->localClient->sasl_agent, saslserv_p->id, IDLEN);
 214         }
 215         else
 216         {
 217                 if (!strcmp(parv[1], "*"))
 218                 {
 219                         sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
 220                         sendto_one(agent_p, ":%s ENCAP %s SASL %s %s D A", me.id, agent_p->servptr->name, source_p->id, agent_p->id);
 221                         source_p->localClient->sasl_out = 0;
 222                         return;
 223                 }
 224
 225                 sendto_one(agent_p, ":%s ENCAP %s SASL %s %s C %s",
 226                                 me.id, agent_p->servptr->name, source_p->id, agent_p->id,
 227                                 parv[1]);
 228         }
 229
 230         source_p->localClient->sasl_out++;
 231 }
 232
 233 static void
 234 me_sasl(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p,
 235         int parc, const char *parv[])
 236 {
 237         struct Client *target_p, *agent_p;
 238         bool in_progress;
 239
 240         /* Let propagate if not addressed to us, or if broadcast.
 241          * Only SASL agents can answer global requests.
 242          */
 243         if(strncmp(parv[2], me.id, 3))
 244                 return;
 245
 246         if((target_p = find_id(parv[2])) == NULL)
 247                 return;
 248
 249         if((agent_p = find_id(parv[1])) == NULL)
 250                 return;
 251
 252         if(source_p != agent_p->servptr) /* WTF?! */
 253                 return;
 254
 255         /* We only accept messages from SASL agents; these must have umode +S
 256          * (so the server must be listed in a service{} block).
 257          */
 258         if(!IsService(agent_p))
 259                 return;
 260
 261         /* If SASL has been aborted, we only want to track authentication failures. */
 262         in_progress = target_p->localClient->sasl_out != 0;
 263
 264         /* Reject if someone has already answered. */
 265         if(*target_p->localClient->sasl_agent && strncmp(parv[1], target_p->localClient->sasl_agent, IDLEN))
 266                 return;
 267         else if(!*target_p->localClient->sasl_agent && in_progress)
 268                 rb_strlcpy(target_p->localClient->sasl_agent, parv[1], IDLEN);
 269
 270         if(*parv[3] == 'C')
 271         {
 272                 if (in_progress) {
 273                         sendto_one(target_p, "AUTHENTICATE %s", parv[4]);
 274                         target_p->localClient->sasl_messages++;
 275                 }
 276         }
 277         else if(*parv[3] == 'D')
 278         {
 279                 if(*parv[4] == 'F')
 280                 {
 281                         if (in_progress) {
 282                                 sendto_one(target_p, form_str(ERR_SASLFAIL), me.name, EmptyString(target_p->name) ? "*" : target_p->name);
 283                         }
 284                         /* Failures with zero messages are just "unknown mechanism" errors; don't count those. */
 285                         if(target_p->localClient->sasl_messages > 0)
 286                         {
 287                                 if(*target_p->name)
 288                                 {
 289                                         /* Allow 2 tries before rate-limiting as some clients try EXTERNAL
 290                                          * then PLAIN right after it if the auth failed, causing the client to be
 291                                          * rate-limited immediately and not being able to login with SASL.
 292                                          */
 293                                         if (target_p->localClient->sasl_failures++ > 0)
 294                                                 target_p->localClient->sasl_next_retry = rb_current_time() + (1 << MIN(target_p->localClient->sasl_failures + 1, 8));
 295                                 }
 296                                 else if(throttle_add((struct sockaddr*)&target_p->localClient->ip))
 297                                 {
 298                                         exit_client(target_p, target_p, &me, "Too many failed authentication attempts");
 299                                         return;
 300                                 }
 301                         }
 302                 }
 303                 else if(*parv[4] == 'S')
 304                 {
 305                         if (in_progress) {
 306                                 sendto_one(target_p, form_str(RPL_SASLSUCCESS), me.name, EmptyString(target_p->name) ? "*" : target_p->name);
 307                                 target_p->localClient->sasl_failures = 0;
 308                                 target_p->localClient->sasl_complete = 1;
 309                                 ServerStats.is_ssuc++;
 310                         }
 311                 }
 312                 *target_p->localClient->sasl_agent = '\0'; /* Blank the stored agent so someone else can answer */
 313                 target_p->localClient->sasl_messages = 0;
 314         }
 315         else if(*parv[3] == 'M')
 316         {
 317                 if (in_progress) {
 318                         sendto_one(target_p, form_str(RPL_SASLMECHS), me.name, EmptyString(target_p->name) ? "*" : target_p->name, parv[4]);
 319                 }
 320         }
 321 }
 322
 323 static void
 324 me_mechlist(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p,
 325             int parc, const char *parv[])
 326 {
 327         rb_strlcpy(mechlist_buf, parv[1], sizeof mechlist_buf);
 328 }
 329
 330 /* If the client never finished authenticating but is
 331  * registering anyway, abort the exchange.
 332  */
 333 static void
 334 abort_sasl(struct Client *data)
 335 {
 336         if(data->localClient->sasl_out == 0 || data->localClient->sasl_complete)
 337                 return;
 338
 339         data->localClient->sasl_out = data->localClient->sasl_complete = 0;
 340         ServerStats.is_sbad++;
 341
 342         if(!IsClosing(data))
 343                 sendto_one(data, form_str(ERR_SASLABORTED), me.name, EmptyString(data->name) ? "*" : data->name);
 344
 345         if(*data->localClient->sasl_agent)
 346         {
 347                 struct Client *agent_p = find_id(data->localClient->sasl_agent);
 348                 if(agent_p)
 349                 {
 350                         sendto_one(agent_p, ":%s ENCAP %s SASL %s %s D A", me.id, agent_p->servptr->name,
 351                                         data->id, agent_p->id);
 352                         return;
 353                 }
 354         }
 355
 356         sendto_server(NULL, NULL, CAP_TS6|CAP_ENCAP, NOCAPS, ":%s ENCAP * SASL %s * D A", me.id,
 357                         data->id);
 358 }
 359
 360 static void
 361 abort_sasl_exit(hook_data_client_exit *data)
 362 {
 363         if (data->target->localClient)
 364                 abort_sasl(data->target);
 365 }
 366
 367 static void
 368 advertise_sasl_cap(bool available)
 369 {
 370         if (sasl_agent_present != available) {
 371                 if (available) {
 372                         sendto_local_clients_with_capability(CLICAP_CAP_NOTIFY, ":%s CAP * NEW :sasl", me.name);
 373                 } else {
 374                         sendto_local_clients_with_capability(CLICAP_CAP_NOTIFY, ":%s CAP * DEL :sasl", me.name);
 375                 }
 376                 sasl_agent_present = available;
 377         }
 378 }
 379
 380 static void
 381 advertise_sasl_new(struct Client *client_p)
 382 {
 383         if (!ConfigFileEntry.sasl_service)
 384                 return;
 385
 386         if (irccmp(client_p->name, ConfigFileEntry.sasl_service))
 387                 return;
 388
 389         advertise_sasl_cap(IsService(client_p));
 390 }
 391
 392 static void
 393 advertise_sasl_exit(void *ignored)
 394 {
 395         if (!ConfigFileEntry.sasl_service)
 396                 return;
 397
 398         if (sasl_agent_present) {
 399                 advertise_sasl_cap(sasl_visible(NULL));
 400         }
 401 }
 402
 403 static void
 404 advertise_sasl_config(void *ignored)
 405 {
 406         advertise_sasl_cap(sasl_visible(NULL));
 407 }