src/src/routers/queryprogram.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2018 */
   6 /* Copyright (c) The Exim Maintainers 2020 */
   7 /* See the file NOTICE for conditions of use and distribution. */
   8
   9 #include "../exim.h"
  10 #include "rf_functions.h"
  11 #include "queryprogram.h"
  12
  13
  14
  15 /* Options specific to the queryprogram router. */
  16
  17 optionlist queryprogram_router_options[] = {
  18   { "*expand_command_group", opt_bool | opt_hidden,
  19       OPT_OFF(queryprogram_router_options_block, expand_cmd_gid) },
  20   { "*expand_command_user", opt_bool | opt_hidden,
  21       OPT_OFF(queryprogram_router_options_block, expand_cmd_uid) },
  22   { "*set_command_group",   opt_bool | opt_hidden,
  23       OPT_OFF(queryprogram_router_options_block, cmd_gid_set) },
  24   { "*set_command_user",    opt_bool | opt_hidden,
  25       OPT_OFF(queryprogram_router_options_block, cmd_uid_set) },
  26   { "command",      opt_stringptr,
  27       OPT_OFF(queryprogram_router_options_block, command) },
  28   { "command_group",opt_expand_gid,
  29       OPT_OFF(queryprogram_router_options_block, cmd_gid) },
  30   { "command_user", opt_expand_uid,
  31       OPT_OFF(queryprogram_router_options_block, cmd_uid) },
  32   { "current_directory", opt_stringptr,
  33       OPT_OFF(queryprogram_router_options_block, current_directory) },
  34   { "timeout",      opt_time,
  35       OPT_OFF(queryprogram_router_options_block, timeout) }
  36 };
  37
  38 /* Size of the options list. An extern variable has to be used so that its
  39 address can appear in the tables drtables.c. */
  40
  41 int queryprogram_router_options_count =
  42   sizeof(queryprogram_router_options)/sizeof(optionlist);
  43
  44
  45 #ifdef MACRO_PREDEF
  46
  47 /* Dummy entries */
  48 queryprogram_router_options_block queryprogram_router_option_defaults = {0};
  49 void queryprogram_router_init(router_instance *rblock) {}
  50 int queryprogram_router_entry(router_instance *rblock, address_item *addr,
  51   struct passwd *pw, int verify, address_item **addr_local,
  52   address_item **addr_remote, address_item **addr_new,
  53   address_item **addr_succeed) {return 0;}
  54
  55 #else   /*!MACRO_PREDEF*/
  56
  57
  58 /* Default private options block for the queryprogram router. */
  59
  60 queryprogram_router_options_block queryprogram_router_option_defaults = {
  61   NULL,         /* command */
  62   60*60,        /* timeout */
  63   (uid_t)(-1),  /* cmd_uid */
  64   (gid_t)(-1),  /* cmd_gid */
  65   FALSE,        /* cmd_uid_set */
  66   FALSE,        /* cmd_gid_set */
  67   US"/",        /* current_directory */
  68   NULL,         /* expand_cmd_gid */
  69   NULL          /* expand_cmd_uid */
  70 };
  71
  72
  73
  74 /*************************************************
  75 *          Initialization entry point            *
  76 *************************************************/
  77
  78 /* Called for each instance, after its options have been read, to enable
  79 consistency checks to be done, or anything else that needs to be set up. */
  80
  81 void
  82 queryprogram_router_init(router_instance *rblock)
  83 {
  84 queryprogram_router_options_block *ob =
  85   (queryprogram_router_options_block *)(rblock->options_block);
  86
  87 /* A command must be given */
  88
  89 if (ob->command == NULL)
  90   log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s router:\n  "
  91     "a command specification is required", rblock->name);
  92
  93 /* A uid/gid must be supplied */
  94
  95 if (!ob->cmd_uid_set && ob->expand_cmd_uid == NULL)
  96   log_write(0, LOG_PANIC_DIE|LOG_CONFIG_FOR, "%s router:\n  "
  97     "command_user must be specified", rblock->name);
  98 }
  99
 100
 101
 102 /*************************************************
 103 *    Process a set of generated new addresses    *
 104 *************************************************/
 105
 106 /* This function sets up a set of newly generated child addresses and puts them
 107 on the new address chain.
 108
 109 Arguments:
 110   rblock                  router block
 111   addr_new                new address chain
 112   addr                    original address
 113   generated               list of generated addresses
 114   addr_prop               the propagated data block, containing errors_to,
 115                             header change stuff, and address_data
 116
 117 Returns:         nothing
 118 */
 119
 120 static void
 121 add_generated(router_instance *rblock, address_item **addr_new,
 122   address_item *addr, address_item *generated,
 123   address_item_propagated *addr_prop)
 124 {
 125 while (generated != NULL)
 126   {
 127   BOOL ignore_error = addr->prop.ignore_error;
 128   address_item *next = generated;
 129
 130   generated = next->next;
 131
 132   next->parent = addr;
 133   next->prop = *addr_prop;
 134   next->prop.ignore_error = next->prop.ignore_error || ignore_error;
 135   next->start_router = rblock->redirect_router;
 136
 137   next->next = *addr_new;
 138   *addr_new = next;
 139
 140   if (addr->child_count == USHRT_MAX)
 141     log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s router generated more than %d "
 142       "child addresses for <%s>", rblock->name, USHRT_MAX, addr->address);
 143   addr->child_count++;
 144
 145   DEBUG(D_route)
 146     debug_printf("%s router generated %s\n", rblock->name, next->address);
 147   }
 148 }
 149
 150
 151
 152
 153 /*************************************************
 154 *              Main entry point                  *
 155 *************************************************/
 156
 157 /* See local README for interface details. This router returns:
 158
 159 DECLINE
 160   . DECLINE returned
 161   . self = DECLINE
 162
 163 PASS
 164   . PASS returned
 165   . timeout of host lookup and pass_on_timeout set
 166   . self = PASS
 167
 168 DEFER
 169   . verifying the errors address caused a deferment or a big disaster such
 170       as an expansion failure (rf_get_errors_address)
 171   . expanding a headers_{add,remove} string caused a deferment or another
 172       expansion error (rf_get_munge_headers)
 173   . a problem in rf_get_transport: no transport when one is needed;
 174       failed to expand dynamic transport; failed to find dynamic transport
 175   . bad lookup type
 176   . problem looking up host (rf_lookup_hostlist)
 177   . self = DEFER or FREEZE
 178   . failure to set up uid/gid for running the command
 179   . failure of transport_set_up_command: too many arguments, expansion fail
 180   . failure to create child process
 181   . child process crashed or timed out or didn't return data
 182   . :defer: in data
 183   . DEFER or FREEZE returned
 184   . problem in redirection data
 185   . unknown transport name or trouble expanding router transport
 186
 187 FAIL
 188   . :fail: in data
 189   . FAIL returned
 190   . self = FAIL
 191
 192 OK
 193   . address added to addr_local or addr_remote for delivery
 194   . new addresses added to addr_new
 195 */
 196
 197 int
 198 queryprogram_router_entry(
 199   router_instance *rblock,        /* data for this instantiation */
 200   address_item *addr,             /* address we are working on */
 201   struct passwd *pw,              /* passwd entry after check_local_user */
 202   int verify,                     /* v_none/v_recipient/v_sender/v_expn */
 203   address_item **addr_local,      /* add it to this if it's local */
 204   address_item **addr_remote,     /* add it to this if it's remote */
 205   address_item **addr_new,        /* put new addresses on here */
 206   address_item **addr_succeed)    /* put old address here on success */
 207 {
 208 int fd_in, fd_out, len, rc;
 209 pid_t pid;
 210 struct passwd *upw = NULL;
 211 uschar buffer[1024];
 212 const uschar **argvptr;
 213 uschar *rword, *rdata, *s;
 214 address_item_propagated addr_prop;
 215 queryprogram_router_options_block *ob =
 216   (queryprogram_router_options_block *)(rblock->options_block);
 217 uschar *current_directory = ob->current_directory;
 218 ugid_block ugid;
 219 uid_t curr_uid = getuid();
 220 gid_t curr_gid = getgid();
 221 uid_t uid = ob->cmd_uid;
 222 gid_t gid = ob->cmd_gid;
 223 uid_t *puid = &uid;
 224 gid_t *pgid = &gid;
 225
 226 DEBUG(D_route) debug_printf("%s router called for %s: domain = %s\n",
 227   rblock->name, addr->address, addr->domain);
 228
 229 ugid.uid_set = ugid.gid_set = FALSE;
 230
 231 /* Set up the propagated data block with the current address_data and the
 232 errors address and extra header stuff. */
 233
 234 bzero(&addr_prop, sizeof(addr_prop));
 235 addr_prop.address_data = deliver_address_data;
 236 tree_dup((tree_node **)&addr_prop.variables, addr->prop.variables);
 237
 238 rc = rf_get_errors_address(addr, rblock, verify, &addr_prop.errors_address);
 239 if (rc != OK) return rc;
 240
 241 rc = rf_get_munge_headers(addr, rblock, &addr_prop.extra_headers,
 242   &addr_prop.remove_headers);
 243 if (rc != OK) return rc;
 244
 245 #ifdef EXPERIMENTAL_SRS
 246 addr_prop.srs_sender = NULL;
 247 #endif
 248
 249 /* Get the fixed or expanded uid under which the command is to run
 250 (initialization ensures that one or the other is set). */
 251
 252 if (!ob->cmd_uid_set)
 253   {
 254   if (!route_find_expanded_user(ob->expand_cmd_uid, rblock->name, US"router",
 255       &upw, &uid, &(addr->message)))
 256     return DEFER;
 257   }
 258
 259 /* Get the fixed or expanded gid, or take the gid from the passwd entry. */
 260
 261 if (!ob->cmd_gid_set)
 262   {
 263   if (ob->expand_cmd_gid != NULL)
 264     {
 265     if (route_find_expanded_group(ob->expand_cmd_gid, rblock->name,
 266         US"router", &gid, &(addr->message)))
 267       return DEFER;
 268     }
 269   else if (upw != NULL)
 270     {
 271     gid = upw->pw_gid;
 272     }
 273   else
 274     {
 275     addr->message = string_sprintf("command_user set without command_group "
 276       "for %s router", rblock->name);
 277     return DEFER;
 278     }
 279   }
 280
 281 DEBUG(D_route) debug_printf("requires uid=%ld gid=%ld current_directory=%s\n",
 282   (long int)uid, (long int)gid, current_directory);
 283
 284 /* If we are not running as root, we will not be able to change uid/gid. */
 285
 286 if (curr_uid != root_uid && (uid != curr_uid || gid != curr_gid))
 287   {
 288   DEBUG(D_route)
 289     {
 290     debug_printf("not running as root: cannot change uid/gid\n");
 291     debug_printf("subprocess will run with uid=%ld gid=%ld\n",
 292       (long int)curr_uid, (long int)curr_gid);
 293     }
 294   puid = pgid = NULL;
 295   }
 296
 297 /* Set up the command to run */
 298
 299 if (!transport_set_up_command(&argvptr, /* anchor for arg list */
 300     ob->command,                        /* raw command */
 301     TRUE,                               /* expand the arguments */
 302     0,                                  /* not relevant when... */
 303     NULL,                               /* no transporting address */
 304     US"queryprogram router",            /* for error messages */
 305     &(addr->message)))                  /* where to put error message */
 306   {
 307   return DEFER;
 308   }
 309
 310 /* Create the child process, making it a group leader. */
 311
 312 if ((pid = child_open_uid(argvptr, NULL, 0077, puid, pgid, &fd_in, &fd_out,
 313                           current_directory, TRUE, US"queryprogram-cmd")) < 0)
 314   {
 315   addr->message = string_sprintf("%s router couldn't create child process: %s",
 316     rblock->name, strerror(errno));
 317   return DEFER;
 318   }
 319
 320 /* Nothing is written to the standard input. */
 321
 322 (void)close(fd_in);
 323
 324 /* Wait for the process to finish, applying the timeout, and inspect its return
 325 code. */
 326
 327 if ((rc = child_close(pid, ob->timeout)) != 0)
 328   {
 329   if (rc > 0)
 330     addr->message = string_sprintf("%s router: command returned non-zero "
 331       "code %d", rblock->name, rc);
 332
 333   else if (rc == -256)
 334     {
 335     addr->message = string_sprintf("%s router: command timed out",
 336       rblock->name);
 337     killpg(pid, SIGKILL);       /* Kill the whole process group */
 338     }
 339
 340   else if (rc == -257)
 341     addr->message = string_sprintf("%s router: wait() failed: %s",
 342       rblock->name, strerror(errno));
 343
 344   else
 345     addr->message = string_sprintf("%s router: command killed by signal %d",
 346       rblock->name, -rc);
 347
 348   return DEFER;
 349   }
 350
 351 /* Read the pipe to get the command's output, and then close it. */
 352
 353 len = read(fd_out, buffer, sizeof(buffer) - 1);
 354 (void)close(fd_out);
 355
 356 /* Failure to return any data is an error. */
 357
 358 if (len <= 0)
 359   {
 360   addr->message = string_sprintf("%s router: command failed to return data",
 361     rblock->name);
 362   return DEFER;
 363   }
 364
 365 /* Get rid of leading and trailing white space, and pick off the first word of
 366 the result. */
 367
 368 while (len > 0 && isspace(buffer[len-1])) len--;
 369 buffer[len] = 0;
 370
 371 DEBUG(D_route) debug_printf("command wrote: %s\n", buffer);
 372
 373 rword = buffer;
 374 while (isspace(*rword)) rword++;
 375 rdata = rword;
 376 while (*rdata != 0 && !isspace(*rdata)) rdata++;
 377 if (*rdata != 0) *rdata++ = 0;
 378
 379 /* The word must be a known yield name. If it is "REDIRECT", the rest of the
 380 line is redirection data, as for a .forward file. It may not contain filter
 381 data, and it may not contain anything other than addresses (no files, no pipes,
 382 no specials). */
 383
 384 if (strcmpic(rword, US"REDIRECT") == 0)
 385   {
 386   int filtertype;
 387   redirect_block redirect;
 388   address_item *generated = NULL;
 389
 390   redirect.string = rdata;
 391   redirect.isfile = FALSE;
 392
 393   rc = rda_interpret(&redirect,  /* redirection data */
 394     RDO_BLACKHOLE |              /* forbid :blackhole: */
 395       RDO_FAIL    |              /* forbid :fail: */
 396       RDO_INCLUDE |              /* forbid :include: */
 397       RDO_REWRITE,               /* rewrite generated addresses */
 398     NULL,                        /* :include: directory not relevant */
 399     NULL,                        /* sieve vacation directory not relevant */
 400     NULL,                        /* sieve enotify mailto owner not relevant */
 401     NULL,                        /* sieve useraddress not relevant */
 402     NULL,                        /* sieve subaddress not relevant */
 403     &ugid,                       /* uid/gid (but not set) */
 404     &generated,                  /* where to hang the results */
 405     &(addr->message),            /* where to put messages */
 406     NULL,                        /* don't skip syntax errors */
 407     &filtertype,                 /* not used; will always be FILTER_FORWARD */
 408     string_sprintf("%s router", rblock->name));
 409
 410   switch (rc)
 411     {
 412     /* FF_DEFER and FF_FAIL can arise only as a result of explicit commands.
 413     If a configured message was supplied, allow it to be  included in an SMTP
 414     response after verifying. */
 415
 416     case FF_DEFER:
 417     if (addr->message == NULL) addr->message = US"forced defer";
 418       else addr->user_message = addr->message;
 419     return DEFER;
 420
 421     case FF_FAIL:
 422     add_generated(rblock, addr_new, addr, generated, &addr_prop);
 423     if (addr->message == NULL) addr->message = US"forced rejection";
 424       else addr->user_message = addr->message;
 425     return FAIL;
 426
 427     case FF_DELIVERED:
 428     break;
 429
 430     case FF_NOTDELIVERED:    /* an empty redirection list is bad */
 431     addr->message = US"no addresses supplied";
 432     /* Fall through */
 433
 434     case FF_ERROR:
 435     default:
 436     addr->basic_errno = ERRNO_BADREDIRECT;
 437     addr->message = string_sprintf("error in redirect data: %s", addr->message);
 438     return DEFER;
 439     }
 440
 441   /* Handle the generated addresses, if any. */
 442
 443   add_generated(rblock, addr_new, addr, generated, &addr_prop);
 444
 445   /* Put the original address onto the succeed queue so that any retry items
 446   that get attached to it get processed. */
 447
 448   addr->next = *addr_succeed;
 449   *addr_succeed = addr;
 450
 451   return OK;
 452   }
 453
 454 /* Handle other returns that are not ACCEPT */
 455
 456 if (strcmpic(rword, US"accept") != 0)
 457   {
 458   if (strcmpic(rword, US"decline") == 0) return DECLINE;
 459   if (strcmpic(rword, US"pass") == 0) return PASS;
 460   addr->message = string_copy(rdata);                /* data is a message */
 461   if (strcmpic(rword, US"fail") == 0)
 462     {
 463     setflag(addr, af_pass_message);
 464     return FAIL;
 465     }
 466   if (strcmpic(rword, US"freeze") == 0) addr->special_action = SPECIAL_FREEZE;
 467   else if (strcmpic(rword, US"defer") != 0)
 468     {
 469     addr->message = string_sprintf("bad command yield: %s %s", rword, rdata);
 470     log_write(0, LOG_PANIC, "%s router: %s", rblock->name, addr->message);
 471     }
 472   return DEFER;
 473   }
 474
 475 /* The command yielded "ACCEPT". The rest of the string is a number of keyed
 476 fields from which we can fish out values using the "extract" expansion
 477 function. To use this feature, we must put the string into the $value variable,
 478 i.e. set lookup_value. */
 479
 480 lookup_value = rdata;
 481 s = expand_string(US"${extract{data}{$value}}");
 482 if (*s != 0) addr_prop.address_data = string_copy(s);
 483
 484 s = expand_string(US"${extract{transport}{$value}}");
 485 lookup_value = NULL;
 486
 487 /* If we found a transport name, find the actual transport */
 488
 489 if (*s != 0)
 490   {
 491   transport_instance *transport;
 492   for (transport = transports; transport; transport = transport->next)
 493     if (Ustrcmp(transport->name, s) == 0) break;
 494   if (!transport)
 495     {
 496     addr->message = string_sprintf("unknown transport name %s yielded by "
 497       "command", s);
 498     log_write(0, LOG_PANIC, "%s router: %s", rblock->name, addr->message);
 499     return DEFER;
 500     }
 501   addr->transport = transport;
 502   }
 503
 504 /* No transport given; get the transport from the router configuration. It may
 505 be fixed or expanded, but there will be an error if it is unset, requested by
 506 the last argument not being NULL. */
 507
 508 else
 509   {
 510   if (!rf_get_transport(rblock->transport_name, &(rblock->transport), addr,
 511        rblock->name, US"transport"))
 512     return DEFER;
 513   addr->transport = rblock->transport;
 514   }
 515
 516 /* See if a host list is given, and if so, look up the addresses. */
 517
 518 lookup_value = rdata;
 519 s = expand_string(US"${extract{hosts}{$value}}");
 520
 521 if (*s != 0)
 522   {
 523   int lookup_type = LK_DEFAULT;
 524   uschar *ss = expand_string(US"${extract{lookup}{$value}}");
 525   lookup_value = NULL;
 526
 527   if (*ss != 0)
 528     {
 529     if (Ustrcmp(ss, "byname") == 0) lookup_type = LK_BYNAME;
 530     else if (Ustrcmp(ss, "bydns") == 0) lookup_type = LK_BYDNS;
 531     else
 532       {
 533       addr->message = string_sprintf("bad lookup type \"%s\" yielded by "
 534         "command", ss);
 535       log_write(0, LOG_PANIC, "%s router: %s", rblock->name, addr->message);
 536       return DEFER;
 537       }
 538     }
 539
 540   host_build_hostlist(&(addr->host_list), s, FALSE);  /* pro tem no randomize */
 541
 542   rc = rf_lookup_hostlist(rblock, addr, rblock->ignore_target_hosts,
 543     lookup_type, hff_defer, addr_new);
 544   if (rc != OK) return rc;
 545   }
 546 lookup_value = NULL;
 547
 548 /* Put the errors address, extra headers, and address_data into this address */
 549
 550 addr->prop = addr_prop;
 551
 552 /* Queue the address for local or remote delivery. */
 553
 554 return rf_queue_add(addr, addr_local, addr_remote, rblock, pw)?
 555   OK : DEFER;
 556 }
 557
 558 #endif   /*!MACRO_PREDEF*/
 559 /* End of routers/queryprogram.c */