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 mapi_cap_list_av2 sasl_cap_list[] = {
 113         { MAPI_CAP_CLIENT, "sasl", &capdata_sasl, &CLICAP_SASL },
 114         { 0, NULL, NULL, NULL },
 115 };
 116
 117 static int
 118 _modinit(void)
 119 {
 120         memset(mechlist_buf, 0, sizeof mechlist_buf);
 121         sasl_agent_present = false;
 122
 123         advertise_sasl_config(NULL);
 124         return 0;
 125 }
 126
 127 static void
 128 _moddeinit(void)
 129 {
 130         advertise_sasl_cap(false);
 131 }
 132
 133 DECLARE_MODULE_AV2(sasl, _modinit, _moddeinit, sasl_clist, NULL, sasl_hfnlist, sasl_cap_list, NULL, sasl_desc);
 134
 135 static void
 136 m_authenticate(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p,
 137         int parc, const char *parv[])
 138 {
 139         struct Client *agent_p = NULL;
 140         struct Client *saslserv_p = NULL;
 141
 142         /* They really should use CAP for their own sake. */
 143         if(!IsCapable(source_p, CLICAP_SASL))
 144                 return;
 145
 146         if(source_p->localClient->sasl_next_retry > rb_current_time())
 147         {
 148                 sendto_one(source_p, form_str(RPL_LOAD2HI), me.name, EmptyString(source_p->name) ? "*" : source_p->name, msgbuf_p->cmd);
 149                 return;
 150         }
 151
 152         if (strlen(client_p->id) == 3 || (source_p->preClient && !EmptyString(source_p->preClient->id)))
 153         {
 154                 exit_client(client_p, client_p, client_p, "Mixing client and server protocol");
 155                 return;
 156         }
 157
 158         if (*parv[1] == ':' || strchr(parv[1], ' '))
 159         {
 160                 exit_client(client_p, client_p, client_p, "Malformed AUTHENTICATE");
 161                 return;
 162         }
 163
 164         saslserv_p = find_named_client(ConfigFileEntry.sasl_service);
 165         if(saslserv_p == NULL || !IsService(saslserv_p))
 166         {
 167                 sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
 168                 return;
 169         }
 170
 171         if(source_p->localClient->sasl_complete)
 172         {
 173                 *source_p->localClient->sasl_agent = '\0';
 174                 source_p->localClient->sasl_complete = 0;
 175         }
 176
 177         if(strlen(parv[1]) > 400)
 178         {
 179                 sendto_one(source_p, form_str(ERR_SASLTOOLONG), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
 180                 return;
 181         }
 182
 183         if(!*source_p->id)
 184         {
 185                 /* Allocate a UID. */
 186                 rb_strlcpy(source_p->id, generate_uid(), sizeof(source_p->id));
 187                 add_to_id_hash(source_p->id, source_p);
 188         }
 189
 190         if(*source_p->localClient->sasl_agent)
 191                 agent_p = find_id(source_p->localClient->sasl_agent);
 192
 193         if(agent_p == NULL)
 194         {
 195                 if (!strcmp(parv[1], "*"))
 196                 {
 197                         sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
 198                         source_p->localClient->sasl_out = 0;
 199                         return;
 200                 }
 201
 202                 sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s H %s %s %c",
 203                                         me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id,
 204                                         source_p->host, source_p->sockhost,
 205                                         IsSSL(source_p) ? 'S' : 'P');
 206
 207                 if (source_p->certfp != NULL)
 208                         sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s S %s %s",
 209                                                 me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id,
 210                                                 parv[1], source_p->certfp);
 211                 else
 212                         sendto_one(saslserv_p, ":%s ENCAP %s SASL %s %s S %s",
 213                                                 me.id, saslserv_p->servptr->name, source_p->id, saslserv_p->id,
 214                                                 parv[1]);
 215
 216                 rb_strlcpy(source_p->localClient->sasl_agent, saslserv_p->id, IDLEN);
 217         }
 218         else
 219         {
 220                 if (!strcmp(parv[1], "*"))
 221                 {
 222                         sendto_one(source_p, form_str(ERR_SASLABORTED), me.name, EmptyString(source_p->name) ? "*" : source_p->name);
 223                         sendto_one(agent_p, ":%s ENCAP %s SASL %s %s D A", me.id, agent_p->servptr->name, source_p->id, agent_p->id);
 224                         source_p->localClient->sasl_out = 0;
 225                         return;
 226                 }
 227
 228                 sendto_one(agent_p, ":%s ENCAP %s SASL %s %s C %s",
 229                                 me.id, agent_p->servptr->name, source_p->id, agent_p->id,
 230                                 parv[1]);
 231         }
 232
 233         source_p->localClient->sasl_out++;
 234 }
 235
 236 static void
 237 me_sasl(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p,
 238         int parc, const char *parv[])
 239 {
 240         struct Client *target_p, *agent_p;
 241         bool in_progress;
 242
 243         /* Let propagate if not addressed to us, or if broadcast.
 244          * Only SASL agents can answer global requests.
 245          */
 246         if(strncmp(parv[2], me.id, 3))
 247                 return;
 248
 249         if((target_p = find_id(parv[2])) == NULL)
 250                 return;
 251
 252         if((agent_p = find_id(parv[1])) == NULL)
 253                 return;
 254
 255         if(source_p != agent_p->servptr) /* WTF?! */
 256                 return;
 257
 258         /* We only accept messages from SASL agents; these must have umode +S
 259          * (so the server must be listed in a service{} block).
 260          */
 261         if(!IsService(agent_p))
 262                 return;
 263
 264         /* If SASL has been aborted, we only want to track authentication failures. */
 265         in_progress = target_p->localClient->sasl_out != 0;
 266
 267         /* Reject if someone has already answered. */
 268         if(*target_p->localClient->sasl_agent && strncmp(parv[1], target_p->localClient->sasl_agent, IDLEN))
 269                 return;
 270         else if(!*target_p->localClient->sasl_agent && in_progress)
 271                 rb_strlcpy(target_p->localClient->sasl_agent, parv[1], IDLEN);
 272
 273         if(*parv[3] == 'C')
 274         {
 275                 if (in_progress) {
 276                         sendto_one(target_p, "AUTHENTICATE %s", parv[4]);
 277                         target_p->localClient->sasl_messages++;
 278                 }
 279         }
 280         else if(*parv[3] == 'D')
 281         {
 282                 if(*parv[4] == 'F')
 283                 {
 284                         if (in_progress) {
 285                                 sendto_one(target_p, form_str(ERR_SASLFAIL), me.name, EmptyString(target_p->name) ? "*" : target_p->name);
 286                         }
 287                         /* Failures with zero messages are just "unknown mechanism" errors; don't count those. */
 288                         if(target_p->localClient->sasl_messages > 0)
 289                         {
 290                                 if(*target_p->name)
 291                                 {
 292                                         /* Allow 2 tries before rate-limiting as some clients try EXTERNAL
 293                                          * then PLAIN right after it if the auth failed, causing the client to be
 294                                          * rate-limited immediately and not being able to login with SASL.
 295                                          */
 296                                         if (target_p->localClient->sasl_failures++ > 0)
 297                                                 target_p->localClient->sasl_next_retry = rb_current_time() + (1 << MIN(target_p->localClient->sasl_failures + 1, 8));
 298                                 }
 299                                 else if(throttle_add((struct sockaddr*)&target_p->localClient->ip))
 300                                 {
 301                                         exit_client(target_p, target_p, &me, "Too many failed authentication attempts");
 302                                         return;
 303                                 }
 304                         }
 305                 }
 306                 else if(*parv[4] == 'S')
 307                 {
 308                         if (in_progress) {
 309                                 sendto_one(target_p, form_str(RPL_SASLSUCCESS), me.name, EmptyString(target_p->name) ? "*" : target_p->name);
 310                                 target_p->localClient->sasl_failures = 0;
 311                                 target_p->localClient->sasl_complete = 1;
 312                                 ServerStats.is_ssuc++;
 313                         }
 314                 }
 315                 *target_p->localClient->sasl_agent = '\0'; /* Blank the stored agent so someone else can answer */
 316                 target_p->localClient->sasl_messages = 0;
 317         }
 318         else if(*parv[3] == 'M')
 319         {
 320                 if (in_progress) {
 321                         sendto_one(target_p, form_str(RPL_SASLMECHS), me.name, EmptyString(target_p->name) ? "*" : target_p->name, parv[4]);
 322                 }
 323         }
 324 }
 325
 326 static void
 327 me_mechlist(struct MsgBuf *msgbuf_p, struct Client *client_p, struct Client *source_p,
 328             int parc, const char *parv[])
 329 {
 330         rb_strlcpy(mechlist_buf, parv[1], sizeof mechlist_buf);
 331 }
 332
 333 /* If the client never finished authenticating but is
 334  * registering anyway, abort the exchange.
 335  */
 336 static void
 337 abort_sasl(struct Client *data)
 338 {
 339         if(data->localClient->sasl_out == 0 || data->localClient->sasl_complete)
 340                 return;
 341
 342         data->localClient->sasl_out = data->localClient->sasl_complete = 0;
 343         ServerStats.is_sbad++;
 344
 345         if(!IsClosing(data))
 346                 sendto_one(data, form_str(ERR_SASLABORTED), me.name, EmptyString(data->name) ? "*" : data->name);
 347
 348         if(*data->localClient->sasl_agent)
 349         {
 350                 struct Client *agent_p = find_id(data->localClient->sasl_agent);
 351                 if(agent_p)
 352                 {
 353                         sendto_one(agent_p, ":%s ENCAP %s SASL %s %s D A", me.id, agent_p->servptr->name,
 354                                         data->id, agent_p->id);
 355                         return;
 356                 }
 357         }
 358
 359         sendto_server(NULL, NULL, CAP_TS6|CAP_ENCAP, NOCAPS, ":%s ENCAP * SASL %s * D A", me.id,
 360                         data->id);
 361 }
 362
 363 static void
 364 abort_sasl_exit(hook_data_client_exit *data)
 365 {
 366         if (data->target->localClient)
 367                 abort_sasl(data->target);
 368 }
 369
 370 static void
 371 advertise_sasl_cap(bool available)
 372 {
 373         if (sasl_agent_present != available) {
 374                 if (available) {
 375                         sendto_local_clients_with_capability(CLICAP_CAP_NOTIFY, ":%s CAP * NEW :sasl", me.name);
 376                 } else {
 377                         sendto_local_clients_with_capability(CLICAP_CAP_NOTIFY, ":%s CAP * DEL :sasl", me.name);
 378                 }
 379                 sasl_agent_present = available;
 380         }
 381 }
 382
 383 static void
 384 advertise_sasl_new(struct Client *client_p)
 385 {
 386         if (!ConfigFileEntry.sasl_service)
 387                 return;
 388
 389         if (irccmp(client_p->name, ConfigFileEntry.sasl_service))
 390                 return;
 391
 392         advertise_sasl_cap(IsService(client_p));
 393 }
 394
 395 static void
 396 advertise_sasl_exit(void *ignored)
 397 {
 398         if (!ConfigFileEntry.sasl_service)
 399                 return;
 400
 401         if (sasl_agent_present) {
 402                 advertise_sasl_cap(sasl_visible(NULL));
 403         }
 404 }
 405
 406 static void
 407 advertise_sasl_config(void *ignored)
 408 {
 409         advertise_sasl_cap(sasl_visible(NULL));
 410 }