src/routers/queryprogram.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2016 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8 #include "../exim.h"
   9 #include "rf_functions.h"
  10 #include "queryprogram.h"
  11
  12
  13
  14 /* Options specific to the queryprogram router. */
  15
  16 optionlist queryprogram_router_options[] = {
  17   { "*expand_command_group", opt_bool | opt_hidden,
  18       (void *)(offsetof(queryprogram_router_options_block, expand_cmd_gid)) },
  19   { "*expand_command_user", opt_bool | opt_hidden,
  20       (void *)(offsetof(queryprogram_router_options_block, expand_cmd_uid)) },
  21   { "*set_command_group",   opt_bool | opt_hidden,
  22       (void *)(offsetof(queryprogram_router_options_block, cmd_gid_set)) },
  23   { "*set_command_user",    opt_bool | opt_hidden,
  24       (void *)(offsetof(queryprogram_router_options_block, cmd_uid_set)) },
  25   { "command",      opt_stringptr,
  26       (void *)(offsetof(queryprogram_router_options_block, command)) },
  27   { "command_group",opt_expand_gid,
  28       (void *)(offsetof(queryprogram_router_options_block, cmd_gid)) },
  29   { "command_user", opt_expand_uid,
  30       (void *)(offsetof(queryprogram_router_options_block, cmd_uid)) },
  31   { "current_directory", opt_stringptr,
  32       (void *)(offsetof(queryprogram_router_options_block, current_directory)) },
  33   { "timeout",      opt_time,
  34       (void *)(offsetof(queryprogram_router_options_block, timeout)) }
  35 };
  36
  37 /* Size of the options list. An extern variable has to be used so that its
  38 address can appear in the tables drtables.c. */
  39
  40 int queryprogram_router_options_count =
  41   sizeof(queryprogram_router_options)/sizeof(optionlist);
  42
  43 /* Default private options block for the queryprogram router. */
  44
  45 queryprogram_router_options_block queryprogram_router_option_defaults = {
  46   NULL,         /* command */
  47   60*60,        /* timeout */
  48   (uid_t)(-1),  /* cmd_uid */
  49   (gid_t)(-1),  /* cmd_gid */
  50   FALSE,        /* cmd_uid_set */
  51   FALSE,        /* cmd_gid_set */
  52   US"/",        /* current_directory */
  53   NULL,         /* expand_cmd_gid */
  54   NULL          /* expand_cmd_uid */
  55 };
  56
  57
  58
  59 /*************************************************
  60 *          Initialization entry point            *
  61 *************************************************/
  62
  63 /* Called for each instance, after its options have been read, to enable
  64 consistency checks to be done, or anything else that needs to be set up. */
  65
  66 void
  67 queryprogram_router_init(router_instance *rblock)
  68 {
  69 queryprogram_router_options_block *ob =
  70   (queryprogram_router_options_block *)(rblock->options_block);
  71
  72 /* A command must be given */
  73
  74 if (ob->command == NULL)
  75   log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s router:\n  "
  76     "a command specification is required", rblock->name);
  77
  78 /* A uid/gid must be supplied */
  79
  80 if (!ob->cmd_uid_set && ob->expand_cmd_uid == NULL)
  81   log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s router:\n  "
  82     "command_user must be specified", rblock->name);
  83 }
  84
  85
  86
  87 /*************************************************
  88 *    Process a set of generated new addresses    *
  89 *************************************************/
  90
  91 /* This function sets up a set of newly generated child addresses and puts them
  92 on the new address chain.
  93
  94 Arguments:
  95   rblock                  router block
  96   addr_new                new address chain
  97   addr                    original address
  98   generated               list of generated addresses
  99   addr_prop               the propagated data block, containing errors_to,
 100                             header change stuff, and address_data
 101
 102 Returns:         nothing
 103 */
 104
 105 static void
 106 add_generated(router_instance *rblock, address_item **addr_new,
 107   address_item *addr, address_item *generated,
 108   address_item_propagated *addr_prop)
 109 {
 110 while (generated != NULL)
 111   {
 112   address_item *next = generated;
 113   generated = next->next;
 114
 115   next->parent = addr;
 116   orflag(next, addr, af_propagate);
 117   next->prop = *addr_prop;
 118   next->start_router = rblock->redirect_router;
 119
 120   next->next = *addr_new;
 121   *addr_new = next;
 122
 123   if (addr->child_count == USHRT_MAX)
 124     log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s router generated more than %d "
 125       "child addresses for <%s>", rblock->name, USHRT_MAX, addr->address);
 126   addr->child_count++;
 127
 128   DEBUG(D_route)
 129     debug_printf("%s router generated %s\n", rblock->name, next->address);
 130   }
 131 }
 132
 133
 134
 135
 136 /*************************************************
 137 *              Main entry point                  *
 138 *************************************************/
 139
 140 /* See local README for interface details. This router returns:
 141
 142 DECLINE
 143   . DECLINE returned
 144   . self = DECLINE
 145
 146 PASS
 147   . PASS returned
 148   . timeout of host lookup and pass_on_timeout set
 149   . self = PASS
 150
 151 DEFER
 152   . verifying the errors address caused a deferment or a big disaster such
 153       as an expansion failure (rf_get_errors_address)
 154   . expanding a headers_{add,remove} string caused a deferment or another
 155       expansion error (rf_get_munge_headers)
 156   . a problem in rf_get_transport: no transport when one is needed;
 157       failed to expand dynamic transport; failed to find dynamic transport
 158   . bad lookup type
 159   . problem looking up host (rf_lookup_hostlist)
 160   . self = DEFER or FREEZE
 161   . failure to set up uid/gid for running the command
 162   . failure of transport_set_up_command: too many arguments, expansion fail
 163   . failure to create child process
 164   . child process crashed or timed out or didn't return data
 165   . :defer: in data
 166   . DEFER or FREEZE returned
 167   . problem in redirection data
 168   . unknown transport name or trouble expanding router transport
 169
 170 FAIL
 171   . :fail: in data
 172   . FAIL returned
 173   . self = FAIL
 174
 175 OK
 176   . address added to addr_local or addr_remote for delivery
 177   . new addresses added to addr_new
 178 */
 179
 180 int
 181 queryprogram_router_entry(
 182   router_instance *rblock,        /* data for this instantiation */
 183   address_item *addr,             /* address we are working on */
 184   struct passwd *pw,              /* passwd entry after check_local_user */
 185   int verify,                     /* v_none/v_recipient/v_sender/v_expn */
 186   address_item **addr_local,      /* add it to this if it's local */
 187   address_item **addr_remote,     /* add it to this if it's remote */
 188   address_item **addr_new,        /* put new addresses on here */
 189   address_item **addr_succeed)    /* put old address here on success */
 190 {
 191 int fd_in, fd_out, len, rc;
 192 pid_t pid;
 193 struct passwd *upw = NULL;
 194 uschar buffer[1024];
 195 const uschar **argvptr;
 196 uschar *rword, *rdata, *s;
 197 address_item_propagated addr_prop;
 198 queryprogram_router_options_block *ob =
 199   (queryprogram_router_options_block *)(rblock->options_block);
 200 uschar *current_directory = ob->current_directory;
 201 ugid_block ugid;
 202 uid_t curr_uid = getuid();
 203 gid_t curr_gid = getgid();
 204 uid_t uid = ob->cmd_uid;
 205 gid_t gid = ob->cmd_gid;
 206 uid_t *puid = &uid;
 207 gid_t *pgid = &gid;
 208
 209 DEBUG(D_route) debug_printf("%s router called for %s: domain = %s\n",
 210   rblock->name, addr->address, addr->domain);
 211
 212 ugid.uid_set = ugid.gid_set = FALSE;
 213
 214 /* Set up the propagated data block with the current address_data and the
 215 errors address and extra header stuff. */
 216
 217 bzero(&addr_prop, sizeof(addr_prop));
 218 addr_prop.address_data = deliver_address_data;
 219
 220 rc = rf_get_errors_address(addr, rblock, verify, &addr_prop.errors_address);
 221 if (rc != OK) return rc;
 222
 223 rc = rf_get_munge_headers(addr, rblock, &addr_prop.extra_headers,
 224   &addr_prop.remove_headers);
 225 if (rc != OK) return rc;
 226
 227 #ifdef EXPERIMENTAL_SRS
 228 addr_prop.srs_sender = NULL;
 229 #endif
 230
 231 /* Get the fixed or expanded uid under which the command is to run
 232 (initialization ensures that one or the other is set). */
 233
 234 if (!ob->cmd_uid_set)
 235   {
 236   if (!route_find_expanded_user(ob->expand_cmd_uid, rblock->name, US"router",
 237       &upw, &uid, &(addr->message)))
 238     return DEFER;
 239   }
 240
 241 /* Get the fixed or expanded gid, or take the gid from the passwd entry. */
 242
 243 if (!ob->cmd_gid_set)
 244   {
 245   if (ob->expand_cmd_gid != NULL)
 246     {
 247     if (route_find_expanded_group(ob->expand_cmd_gid, rblock->name,
 248         US"router", &gid, &(addr->message)))
 249       return DEFER;
 250     }
 251   else if (upw != NULL)
 252     {
 253     gid = upw->pw_gid;
 254     }
 255   else
 256     {
 257     addr->message = string_sprintf("command_user set without command_group "
 258       "for %s router", rblock->name);
 259     return DEFER;
 260     }
 261   }
 262
 263 DEBUG(D_route) debug_printf("requires uid=%ld gid=%ld current_directory=%s\n",
 264   (long int)uid, (long int)gid, current_directory);
 265
 266 /* If we are not running as root, we will not be able to change uid/gid. */
 267
 268 if (curr_uid != root_uid && (uid != curr_uid || gid != curr_gid))
 269   {
 270   DEBUG(D_route)
 271     {
 272     debug_printf("not running as root: cannot change uid/gid\n");
 273     debug_printf("subprocess will run with uid=%ld gid=%ld\n",
 274       (long int)curr_uid, (long int)curr_gid);
 275     }
 276   puid = pgid = NULL;
 277   }
 278
 279 /* Set up the command to run */
 280
 281 if (!transport_set_up_command(&argvptr, /* anchor for arg list */
 282     ob->command,                        /* raw command */
 283     TRUE,                               /* expand the arguments */
 284     0,                                  /* not relevant when... */
 285     NULL,                               /* no transporting address */
 286     US"queryprogram router",            /* for error messages */
 287     &(addr->message)))                  /* where to put error message */
 288   {
 289   return DEFER;
 290   }
 291
 292 /* Create the child process, making it a group leader. */
 293
 294 pid = child_open_uid(argvptr, NULL, 0077, puid, pgid, &fd_in, &fd_out,
 295   current_directory, TRUE);
 296
 297 if (pid < 0)
 298   {
 299   addr->message = string_sprintf("%s router couldn't create child process: %s",
 300     rblock->name, strerror(errno));
 301   return DEFER;
 302   }
 303
 304 /* Nothing is written to the standard input. */
 305
 306 (void)close(fd_in);
 307
 308 /* Wait for the process to finish, applying the timeout, and inspect its return
 309 code. */
 310
 311 if ((rc = child_close(pid, ob->timeout)) != 0)
 312   {
 313   if (rc > 0)
 314     addr->message = string_sprintf("%s router: command returned non-zero "
 315       "code %d", rblock->name, rc);
 316
 317   else if (rc == -256)
 318     {
 319     addr->message = string_sprintf("%s router: command timed out",
 320       rblock->name);
 321     killpg(pid, SIGKILL);       /* Kill the whole process group */
 322     }
 323
 324   else if (rc == -257)
 325     addr->message = string_sprintf("%s router: wait() failed: %s",
 326       rblock->name, strerror(errno));
 327
 328   else
 329     addr->message = string_sprintf("%s router: command killed by signal %d",
 330       rblock->name, -rc);
 331
 332   return DEFER;
 333   }
 334
 335 /* Read the pipe to get the command's output, and then close it. */
 336
 337 len = read(fd_out, buffer, sizeof(buffer) - 1);
 338 (void)close(fd_out);
 339
 340 /* Failure to return any data is an error. */
 341
 342 if (len <= 0)
 343   {
 344   addr->message = string_sprintf("%s router: command failed to return data",
 345     rblock->name);
 346   return DEFER;
 347   }
 348
 349 /* Get rid of leading and trailing white space, and pick off the first word of
 350 the result. */
 351
 352 while (len > 0 && isspace(buffer[len-1])) len--;
 353 buffer[len] = 0;
 354
 355 DEBUG(D_route) debug_printf("command wrote: %s\n", buffer);
 356
 357 rword = buffer;
 358 while (isspace(*rword)) rword++;
 359 rdata = rword;
 360 while (*rdata != 0 && !isspace(*rdata)) rdata++;
 361 if (*rdata != 0) *rdata++ = 0;
 362
 363 /* The word must be a known yield name. If it is "REDIRECT", the rest of the
 364 line is redirection data, as for a .forward file. It may not contain filter
 365 data, and it may not contain anything other than addresses (no files, no pipes,
 366 no specials). */
 367
 368 if (strcmpic(rword, US"REDIRECT") == 0)
 369   {
 370   int filtertype;
 371   redirect_block redirect;
 372   address_item *generated = NULL;
 373
 374   redirect.string = rdata;
 375   redirect.isfile = FALSE;
 376
 377   rc = rda_interpret(&redirect,  /* redirection data */
 378     RDO_BLACKHOLE |              /* forbid :blackhole: */
 379       RDO_FAIL    |              /* forbid :fail: */
 380       RDO_INCLUDE |              /* forbid :include: */
 381       RDO_REWRITE,               /* rewrite generated addresses */
 382     NULL,                        /* :include: directory not relevant */
 383     NULL,                        /* sieve vacation directory not relevant */
 384     NULL,                        /* sieve enotify mailto owner not relevant */
 385     NULL,                        /* sieve useraddress not relevant */
 386     NULL,                        /* sieve subaddress not relevant */
 387     &ugid,                       /* uid/gid (but not set) */
 388     &generated,                  /* where to hang the results */
 389     &(addr->message),            /* where to put messages */
 390     NULL,                        /* don't skip syntax errors */
 391     &filtertype,                 /* not used; will always be FILTER_FORWARD */
 392     string_sprintf("%s router", rblock->name));
 393
 394   switch (rc)
 395     {
 396     /* FF_DEFER and FF_FAIL can arise only as a result of explicit commands.
 397     If a configured message was supplied, allow it to be  included in an SMTP
 398     response after verifying. */
 399
 400     case FF_DEFER:
 401     if (addr->message == NULL) addr->message = US"forced defer";
 402       else addr->user_message = addr->message;
 403     return DEFER;
 404
 405     case FF_FAIL:
 406     add_generated(rblock, addr_new, addr, generated, &addr_prop);
 407     if (addr->message == NULL) addr->message = US"forced rejection";
 408       else addr->user_message = addr->message;
 409     return FAIL;
 410
 411     case FF_DELIVERED:
 412     break;
 413
 414     case FF_NOTDELIVERED:    /* an empty redirection list is bad */
 415     addr->message = US"no addresses supplied";
 416     /* Fall through */
 417
 418     case FF_ERROR:
 419     default:
 420     addr->basic_errno = ERRNO_BADREDIRECT;
 421     addr->message = string_sprintf("error in redirect data: %s", addr->message);
 422     return DEFER;
 423     }
 424
 425   /* Handle the generated addresses, if any. */
 426
 427   add_generated(rblock, addr_new, addr, generated, &addr_prop);
 428
 429   /* Put the original address onto the succeed queue so that any retry items
 430   that get attached to it get processed. */
 431
 432   addr->next = *addr_succeed;
 433   *addr_succeed = addr;
 434
 435   return OK;
 436   }
 437
 438 /* Handle other returns that are not ACCEPT */
 439
 440 if (strcmpic(rword, US"accept") != 0)
 441   {
 442   if (strcmpic(rword, US"decline") == 0) return DECLINE;
 443   if (strcmpic(rword, US"pass") == 0) return PASS;
 444   addr->message = string_copy(rdata);                /* data is a message */
 445   if (strcmpic(rword, US"fail") == 0)
 446     {
 447     setflag(addr, af_pass_message);
 448     return FAIL;
 449     }
 450   if (strcmpic(rword, US"freeze") == 0) addr->special_action = SPECIAL_FREEZE;
 451   else if (strcmpic(rword, US"defer") != 0)
 452     {
 453     addr->message = string_sprintf("bad command yield: %s %s", rword, rdata);
 454     log_write(0, LOG_PANIC, "%s router: %s", rblock->name, addr->message);
 455     }
 456   return DEFER;
 457   }
 458
 459 /* The command yielded "ACCEPT". The rest of the string is a number of keyed
 460 fields from which we can fish out values using the "extract" expansion
 461 function. To use this feature, we must put the string into the $value variable,
 462 i.e. set lookup_value. */
 463
 464 lookup_value = rdata;
 465 s = expand_string(US"${extract{data}{$value}}");
 466 if (*s != 0) addr_prop.address_data = string_copy(s);
 467
 468 s = expand_string(US"${extract{transport}{$value}}");
 469 lookup_value = NULL;
 470
 471 /* If we found a transport name, find the actual transport */
 472
 473 if (*s != 0)
 474   {
 475   transport_instance *transport;
 476   for (transport = transports; transport != NULL; transport = transport->next)
 477     if (Ustrcmp(transport->name, s) == 0) break;
 478   if (transport == NULL)
 479     {
 480     addr->message = string_sprintf("unknown transport name %s yielded by "
 481       "command", s);
 482     log_write(0, LOG_PANIC, "%s router: %s", rblock->name, addr->message);
 483     return DEFER;
 484     }
 485   addr->transport = transport;
 486   }
 487
 488 /* No transport given; get the transport from the router configuration. It may
 489 be fixed or expanded, but there will be an error if it is unset, requested by
 490 the last argument not being NULL. */
 491
 492 else
 493   {
 494   if (!rf_get_transport(rblock->transport_name, &(rblock->transport), addr,
 495        rblock->name, US"transport"))
 496     return DEFER;
 497   addr->transport = rblock->transport;
 498   }
 499
 500 /* See if a host list is given, and if so, look up the addresses. */
 501
 502 lookup_value = rdata;
 503 s = expand_string(US"${extract{hosts}{$value}}");
 504
 505 if (*s != 0)
 506   {
 507   int lookup_type = lk_default;
 508   uschar *ss = expand_string(US"${extract{lookup}{$value}}");
 509   lookup_value = NULL;
 510
 511   if (*ss != 0)
 512     {
 513     if (Ustrcmp(ss, "byname") == 0) lookup_type = lk_byname;
 514     else if (Ustrcmp(ss, "bydns") == 0) lookup_type = lk_bydns;
 515     else
 516       {
 517       addr->message = string_sprintf("bad lookup type \"%s\" yielded by "
 518         "command", ss);
 519       log_write(0, LOG_PANIC, "%s router: %s", rblock->name, addr->message);
 520       return DEFER;
 521       }
 522     }
 523
 524   host_build_hostlist(&(addr->host_list), s, FALSE);  /* pro tem no randomize */
 525
 526   rc = rf_lookup_hostlist(rblock, addr, rblock->ignore_target_hosts,
 527     lookup_type, hff_defer, addr_new);
 528   if (rc != OK) return rc;
 529   }
 530 lookup_value = NULL;
 531
 532 /* Put the errors address, extra headers, and address_data into this address */
 533
 534 addr->prop = addr_prop;
 535
 536 /* Queue the address for local or remote delivery. */
 537
 538 return rf_queue_add(addr, addr_local, addr_remote, rblock, pw)?
 539   OK : DEFER;
 540 }
 541
 542 /* End of routers/queryprogram.c */