Mercurial > dnsbl
annotate src/dnsbl.cpp @ 134:f9917ce924a3
all dns lookups fully qualified, my_read() bug fix
| author | carl |
|---|---|
| date | Wed, 02 Aug 2006 21:06:05 -0700 |
| parents | ae9daf43d8eb |
| children | f4746d8a12a3 |
| rev | line source |
|---|---|
| 94 | 1 /* |
| 2 | |
| 3 Copyright (c) 2004, 2005 Carl Byington - 510 Software Group, released | |
| 4 under the GPL version 2 or any later version at your choice available at | |
| 5 http://www.fsf.org/licenses/gpl.txt | |
| 6 | |
| 7 Based on a sample milter Copyright (c) 2000-2003 Sendmail, Inc. and its | |
| 8 suppliers. Inspired by the DCC by Rhyolite Software | |
| 9 | |
| 10 -r port The port used to talk to our internal dns resolver processes | |
| 11 -p port The port through which the MTA will connect to this milter. | |
| 12 -t sec The timeout value. | |
| 13 -c Check the config, and print a copy to stdout. Don't start the | |
| 14 milter or do anything with the socket. | |
| 15 -s Stress test by loading and deleting the current config in a loop. | |
| 16 -d increase debug level | |
| 17 -e f|t Print the results of looking up from address f and to address | |
| 18 t in the current config | |
| 19 | |
| 20 */ | |
| 21 | |
| 22 | |
| 23 // from sendmail sample | |
| 24 #include <sys/types.h> | |
| 25 #include <sys/stat.h> | |
| 26 #include <errno.h> | |
| 27 #include <sysexits.h> | |
| 28 #include <unistd.h> | |
| 29 | |
| 30 // needed for socket io | |
| 31 #include <sys/ioctl.h> | |
| 32 #include <net/if.h> | |
| 33 #include <arpa/inet.h> | |
| 34 #include <netinet/in.h> | |
| 35 #include <netinet/tcp.h> | |
| 36 #include <netdb.h> | |
| 37 #include <sys/socket.h> | |
| 38 #include <sys/un.h> | |
| 39 | |
| 40 // needed for thread | |
| 41 #include <pthread.h> | |
| 42 | |
| 43 // needed for std c++ collections | |
| 44 #include <set> | |
| 45 #include <map> | |
| 46 #include <list> | |
| 47 | |
| 48 // for the dns resolver | |
| 49 #include <netinet/in.h> | |
| 50 #include <arpa/nameser.h> | |
| 51 #include <resolv.h> | |
| 52 | |
| 53 // misc stuff needed here | |
| 54 #include <ctype.h> | |
| 55 #include <syslog.h> | |
| 56 #include <pwd.h> | |
| 57 #include <sys/wait.h> /* header for waitpid() and various macros */ | |
| 58 #include <signal.h> /* header for signal functions */ | |
| 59 | |
| 60 #include "includes.h" | |
| 61 | |
| 62 static char* dnsbl_version="$Id$"; | |
| 63 | |
| 64 | |
| 65 extern "C" { | |
| 66 #include "libmilter/mfapi.h" | |
| 67 sfsistat mlfi_connect(SMFICTX *ctx, char *hostname, _SOCK_ADDR *hostaddr); | |
| 68 sfsistat mlfi_envfrom(SMFICTX *ctx, char **argv); | |
| 69 sfsistat mlfi_envrcpt(SMFICTX *ctx, char **argv); | |
| 70 sfsistat mlfi_body(SMFICTX *ctx, u_char *data, size_t len); | |
| 71 sfsistat mlfi_eom(SMFICTX *ctx); | |
| 72 sfsistat mlfi_abort(SMFICTX *ctx); | |
| 73 sfsistat mlfi_close(SMFICTX *ctx); | |
| 74 void sig_chld(int signo); | |
| 75 } | |
| 76 | |
| 77 int debug_syslog = 0; | |
| 78 bool syslog_opened = false; | |
| 79 bool use_syslog = true; // false to printf | |
| 80 bool loader_run = true; // used to stop the config loader thread | |
| 81 CONFIG *config = NULL; // protected by the config_mutex | |
| 82 int generation = 0; // protected by the config_mutex | |
| 83 const int maxlen = 1000; // used for snprintf buffers | |
| 84 | |
| 85 pthread_mutex_t config_mutex; | |
| 86 pthread_mutex_t syslog_mutex; | |
| 87 pthread_mutex_t resolve_mutex; | |
| 88 pthread_mutex_t fd_pool_mutex; | |
| 89 | |
| 90 std::set<int> fd_pool; | |
|
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91 int NULL_SOCKET = -1; |
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92 const time_t ERROR_SOCKET_TIME = 60; // number of seconds between attempts to open a socket to the dns resolver process |
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93 char *resolver_port = NULL; // unix domain socket to talk to the dns resolver process |
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94 int resolver_socket = NULL_SOCKET; // socket used to listen for resolver requests |
| 94 | 95 time_t last_error_time; |
| 96 int resolver_sock_count = 0; // protected with fd_pool_mutex | |
| 97 int resolver_pool_size = 0; // protected with fd_pool_mutex | |
| 98 | |
| 99 | |
| 100 struct ns_map { | |
| 101 // all the strings are owned by the keys/values in the ns_host string map | |
| 102 string_map ns_host; // nameserver name -> host name that uses this name server | |
| 103 ns_mapper ns_ip; // nameserver name -> ip address of the name server | |
| 104 ~ns_map(); | |
| 105 void add(char *name, char *refer); | |
| 106 }; | |
| 107 | |
| 108 | |
| 109 ns_map::~ns_map() { | |
| 110 for (string_map::iterator i=ns_host.begin(); i!=ns_host.end(); i++) { | |
| 111 char *x = (*i).first; | |
| 112 char *y = (*i).second; | |
| 113 free(x); | |
| 114 free(y); | |
| 115 } | |
| 116 ns_ip.clear(); | |
| 117 ns_host.clear(); | |
| 118 } | |
| 119 | |
| 120 | |
| 121 void ns_map::add(char *name, char *refer) { | |
| 122 string_map::iterator i = ns_host.find(name); | |
| 123 if (i != ns_host.end()) return; | |
| 124 char *x = strdup(name); | |
| 125 char *y = strdup(refer); | |
| 126 ns_ip[x] = 0; | |
| 127 ns_host[x] = y; | |
| 128 | |
| 129 } | |
| 130 | |
| 131 // packed structure to allow a single socket write to dump the | |
| 132 // length and the following answer. The packing attribute is gcc specific. | |
| 133 struct glommer { | |
| 134 int length; | |
| 135 #ifdef NS_PACKETSZ | |
| 115 | 136 u_char answer[NS_PACKETSZ*4]; // with a resolver, we return resolver answers |
| 94 | 137 #else |
| 138 int answer; // without a resolver, we return a single ip4 address, 0 == no answer | |
| 139 #endif | |
| 140 } __attribute__ ((packed)); | |
| 141 | |
| 142 | |
| 143 //////////////////////////////////////////////// | |
| 144 // helper to discard the strings held by a context_map | |
| 145 // | |
| 146 void discard(context_map &cm); | |
| 147 void discard(context_map &cm) { | |
| 148 for (context_map::iterator i=cm.begin(); i!=cm.end(); i++) { | |
| 149 char *x = (*i).first; | |
| 150 free(x); | |
| 151 } | |
| 152 cm.clear(); | |
| 153 } | |
| 154 | |
| 155 | |
| 156 //////////////////////////////////////////////// | |
| 157 // helper to register a string in a context_map | |
| 158 // | |
| 159 void register_string(context_map &cm, char *name, CONTEXT *con); | |
| 160 void register_string(context_map &cm, char *name, CONTEXT *con) { | |
| 161 context_map::iterator i = cm.find(name); | |
| 162 if (i != cm.end()) return; | |
| 163 char *x = strdup(name); | |
| 164 cm[x] = con; | |
| 165 } | |
| 166 | |
| 167 | |
| 168 //////////////////////////////////////////////// | |
| 169 // disconnect the fd from the dns resolver process | |
| 170 // | |
| 171 void my_disconnect(int sock, bool decrement = true); | |
| 172 void my_disconnect(int sock, bool decrement) { | |
| 173 if (sock != NULL_SOCKET) { | |
| 174 if (decrement) { | |
| 175 pthread_mutex_lock(&fd_pool_mutex); | |
| 176 resolver_sock_count--; | |
| 177 pthread_mutex_unlock(&fd_pool_mutex); | |
| 178 } | |
| 179 shutdown(sock, SHUT_RDWR); | |
| 180 close(sock); | |
| 181 } | |
| 182 } | |
| 183 | |
| 184 | |
| 185 //////////////////////////////////////////////// | |
| 186 // return fd connected to the dns resolver process | |
| 187 // | |
| 188 int my_connect(); | |
| 189 int my_connect() { | |
| 190 // if we have had recent errors, don't even try to open the socket | |
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191 if ((time(NULL) - last_error_time) < ERROR_SOCKET_TIME) return NULL_SOCKET; |
| 94 | 192 |
| 193 // nothing recent, maybe this time it will work | |
| 194 int sock = NULL_SOCKET; | |
| 195 sockaddr_un server; | |
| 196 memset(&server, '\0', sizeof(server)); | |
| 197 server.sun_family = AF_UNIX; | |
| 198 strncpy(server.sun_path, resolver_port, sizeof(server.sun_path)-1); | |
| 199 sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
| 200 if (sock != NULL_SOCKET) { | |
| 201 bool rc = (connect(sock, (sockaddr *)&server, sizeof(server)) == 0); | |
| 202 if (!rc) { | |
| 203 my_disconnect(sock, false); | |
| 204 sock = NULL_SOCKET; | |
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205 last_error_time = time(NULL); |
| 94 | 206 } |
| 207 } | |
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208 else last_error_time = time(NULL); |
| 94 | 209 if (sock != NULL_SOCKET) { |
| 210 pthread_mutex_lock(&fd_pool_mutex); | |
| 211 resolver_sock_count++; | |
| 212 pthread_mutex_unlock(&fd_pool_mutex); | |
| 213 } | |
| 214 return sock; | |
| 215 } | |
| 216 | |
| 217 | |
| 218 mlfiPriv::mlfiPriv() { | |
| 219 pthread_mutex_lock(&config_mutex); | |
| 220 pc = config; | |
| 221 pc->reference_count++; | |
| 222 pthread_mutex_unlock(&config_mutex); | |
| 223 get_fd(); | |
| 224 ip = 0; | |
| 225 mailaddr = NULL; | |
| 226 queueid = NULL; | |
| 227 authenticated = false; | |
| 228 have_whites = false; | |
| 229 only_whites = true; | |
| 230 memory = NULL; | |
| 231 scanner = NULL; | |
| 232 content_suffix = NULL; | |
| 233 content_message = NULL; | |
| 119 | 234 uribl_suffix = NULL; |
| 235 uribl_message = NULL; | |
| 94 | 236 content_host_ignore = NULL; |
| 237 } | |
| 238 | |
| 239 mlfiPriv::~mlfiPriv() { | |
| 240 return_fd(); | |
| 241 pthread_mutex_lock(&config_mutex); | |
| 242 pc->reference_count--; | |
| 243 pthread_mutex_unlock(&config_mutex); | |
| 244 reset(true); | |
| 245 } | |
| 246 | |
| 247 void mlfiPriv::reset(bool final) { | |
| 248 if (mailaddr) free(mailaddr); | |
| 249 if (queueid) free(queueid); | |
| 250 discard(env_to); | |
| 251 if (memory) delete memory; | |
| 252 if (scanner) delete scanner; | |
| 253 if (!final) { | |
| 254 mailaddr = NULL; | |
| 255 queueid = NULL; | |
| 256 authenticated = false; | |
| 257 have_whites = false; | |
| 258 only_whites = true; | |
| 259 memory = NULL; | |
| 260 scanner = NULL; | |
| 261 content_suffix = NULL; | |
| 262 content_message = NULL; | |
| 119 | 263 uribl_suffix = NULL; |
| 264 uribl_message = NULL; | |
| 94 | 265 content_host_ignore = NULL; |
| 266 } | |
| 267 } | |
| 268 | |
| 269 void mlfiPriv::get_fd() { | |
| 270 err = true; | |
| 271 fd = NULL_SOCKET; | |
| 272 int result = pthread_mutex_lock(&fd_pool_mutex); | |
| 273 if (!result) { | |
| 274 std::set<int>::iterator i; | |
| 275 i = fd_pool.begin(); | |
| 276 if (i != fd_pool.end()) { | |
| 277 // have at least one fd in the pool | |
| 278 err = false; | |
| 279 fd = *i; | |
| 280 fd_pool.erase(fd); | |
| 281 resolver_pool_size--; | |
| 282 pthread_mutex_unlock(&fd_pool_mutex); | |
| 283 } | |
| 284 else { | |
| 285 // pool is empty, get a new fd | |
| 286 pthread_mutex_unlock(&fd_pool_mutex); | |
| 287 fd = my_connect(); | |
| 288 err = (fd == NULL_SOCKET); | |
| 289 } | |
| 290 } | |
| 291 else { | |
| 292 // cannot lock the pool, just get a new fd | |
| 293 fd = my_connect(); | |
| 294 err = (fd == NULL_SOCKET); | |
| 295 } | |
| 296 } | |
| 297 | |
| 298 void mlfiPriv::return_fd() { | |
| 299 if (err) { | |
| 300 // this fd got a socket error, so close it, rather than returning it to the pool | |
| 301 my_disconnect(fd); | |
| 302 } | |
| 303 else { | |
| 304 int result = pthread_mutex_lock(&fd_pool_mutex); | |
| 305 if (!result) { | |
| 306 if ((resolver_sock_count > resolver_pool_size*5) || (resolver_pool_size < 5)) { | |
| 307 // return the fd to the pool | |
| 308 fd_pool.insert(fd); | |
| 309 resolver_pool_size++; | |
| 310 pthread_mutex_unlock(&fd_pool_mutex); | |
| 311 } | |
| 312 else { | |
| 313 // more than 20% of the open resolver sockets are in the pool, and the | |
| 314 // pool as at least 5 sockets. that is enough, so just close this one. | |
| 315 pthread_mutex_unlock(&fd_pool_mutex); | |
| 316 my_disconnect(fd); | |
| 317 } | |
| 318 } | |
| 319 else { | |
| 320 // could not lock the pool, so just close the fd | |
| 321 my_disconnect(fd); | |
| 322 } | |
| 323 } | |
| 324 } | |
| 325 | |
| 326 int mlfiPriv::my_write(char *buf, int len) { | |
| 327 if (err) return 0; | |
| 328 int rs = 0; | |
| 329 while (len) { | |
| 330 int ws = write(fd, buf, len); | |
| 331 if (ws > 0) { | |
| 332 rs += ws; | |
| 333 len -= ws; | |
| 334 buf += ws; | |
| 335 } | |
| 336 else { | |
| 337 // peer closed the socket! | |
| 338 rs = 0; | |
| 339 err = true; | |
| 340 break; | |
| 341 } | |
| 342 } | |
| 343 return rs; | |
| 344 } | |
| 345 | |
| 346 int mlfiPriv::my_read(char *buf, int len) { | |
| 347 if (err) return 0; | |
| 348 int rs = 0; | |
| 134 | 349 while (len) { |
| 94 | 350 int ws = read(fd, buf, len); |
| 351 if (ws > 0) { | |
| 352 rs += ws; | |
| 353 len -= ws; | |
| 354 buf += ws; | |
| 355 } | |
| 356 else { | |
| 357 // peer closed the socket! | |
| 358 rs = 0; | |
| 359 err = true; | |
| 360 break; | |
| 361 } | |
| 362 } | |
| 363 return rs; | |
| 364 } | |
| 365 | |
| 366 void mlfiPriv::need_content_filter(char *rcpt, CONTEXT &con) { | |
| 367 register_string(env_to, rcpt, &con); | |
| 368 if (!memory) { | |
| 369 // first recipient that needs content filtering sets all | |
| 370 // the content filtering parameters | |
| 117 | 371 memory = new recorder(this, con.get_html_tags(), con.get_content_tlds(), con.get_content_cctlds()); |
| 94 | 372 scanner = new url_scanner(memory); |
| 373 content_suffix = con.get_content_suffix(); | |
| 374 content_message = con.get_content_message(); | |
| 119 | 375 uribl_suffix = con.get_uribl_suffix(); |
| 376 uribl_message = con.get_uribl_message(); | |
| 94 | 377 content_host_ignore = &con.get_content_host_ignore(); |
| 378 } | |
| 379 } | |
| 380 | |
| 381 #define MLFIPRIV ((struct mlfiPriv *) smfi_getpriv(ctx)) | |
| 382 | |
| 383 | |
| 384 //////////////////////////////////////////////// | |
| 385 // syslog a message | |
| 386 // | |
| 387 void my_syslog(mlfiPriv *priv, char *text) { | |
| 388 char buf[maxlen]; | |
| 389 if (priv) { | |
| 390 snprintf(buf, sizeof(buf), "%s: %s", priv->queueid, text); | |
| 391 text = buf; | |
| 392 } | |
| 393 if (use_syslog) { | |
| 394 pthread_mutex_lock(&syslog_mutex); | |
| 395 if (!syslog_opened) { | |
| 396 openlog("dnsbl", LOG_PID, LOG_MAIL); | |
| 397 syslog_opened = true; | |
| 398 } | |
| 399 syslog(LOG_NOTICE, "%s", text); | |
| 400 pthread_mutex_unlock(&syslog_mutex); | |
| 401 } | |
| 402 else { | |
| 403 printf("%s \n", text); | |
| 404 } | |
| 405 } | |
| 406 | |
| 407 void my_syslog(char *text) { | |
| 408 my_syslog(NULL, text); | |
| 409 } | |
| 410 | |
| 411 | |
| 412 //////////////////////////////////////////////// | |
| 413 // read a resolver request from the socket, process it, and | |
| 414 // write the result back to the socket. | |
| 415 | |
| 416 void process_resolver_requests(int socket); | |
| 417 void process_resolver_requests(int socket) { | |
| 418 #ifdef NS_MAXDNAME | |
| 419 char question[NS_MAXDNAME]; | |
| 420 #else | |
| 421 char question[1000]; | |
| 422 #endif | |
| 423 glommer glom; | |
| 424 | |
| 425 int maxq = sizeof(question); | |
| 426 while (true) { | |
| 427 // read a question | |
| 428 int rs = 0; | |
| 429 while (rs < maxq) { | |
| 430 int ns = read(socket, question+rs, maxq-rs); | |
| 431 if (ns > 0) { | |
| 432 rs += ns; | |
| 433 if (question[rs-1] == '\0') { | |
| 434 // last byte read was the null terminator, we are done | |
| 435 break; | |
| 436 } | |
| 437 } | |
| 438 else { | |
| 439 // peer closed the socket | |
| 440 #ifdef RESOLVER_DEBUG | |
| 441 my_syslog("process_resolver_requests() peer closed socket while reading question"); | |
| 442 #endif | |
| 443 shutdown(socket, SHUT_RDWR); | |
| 444 close(socket); | |
| 445 return; | |
| 446 } | |
| 447 } | |
| 448 question[rs-1] = '\0'; // ensure null termination | |
| 449 | |
| 450 // find the answer | |
| 451 #ifdef NS_PACKETSZ | |
| 452 #ifdef RESOLVER_DEBUG | |
| 453 char text[1000]; | |
| 454 snprintf(text, sizeof(text), "process_resolver_requests() has a question %s", question); | |
| 455 my_syslog(text); | |
| 456 #endif | |
| 457 glom.length = res_search(question, ns_c_in, ns_t_a, glom.answer, sizeof(glom.answer)); | |
| 458 if (glom.length < 0) glom.length = 0; // represent all errors as zero length answers | |
| 459 #else | |
| 460 glom.length = sizeof(glom.answer); | |
| 461 glom.answer = 0; | |
| 462 struct hostent *host = gethostbyname(question); | |
| 463 if (host && (host->h_addrtype == AF_INET)) { | |
| 464 memcpy(&glom.answer, host->h_addr, sizeof(glom.answer)); | |
| 465 } | |
| 466 #endif | |
| 467 | |
| 468 // write the answer | |
| 469 char *buf = (char *)&glom; | |
| 470 int len = glom.length + sizeof(glom.length); | |
| 471 #ifdef RESOLVER_DEBUG | |
| 472 snprintf(text, sizeof(text), "process_resolver_requests() writing answer length %d for total %d", glom.length, len); | |
| 473 my_syslog(text); | |
| 474 #endif | |
| 475 int ws = 0; | |
| 476 while (len > ws) { | |
| 477 int ns = write(socket, buf+ws, len-ws); | |
| 478 if (ns > 0) { | |
| 479 ws += ns; | |
| 480 } | |
| 481 else { | |
| 482 // peer closed the socket! | |
| 483 #ifdef RESOLVER_DEBUG | |
| 484 my_syslog("process_resolver_requests() peer closed socket while writing answer"); | |
| 485 #endif | |
| 486 shutdown(socket, SHUT_RDWR); | |
| 487 close(socket); | |
| 488 return; | |
| 489 } | |
| 490 } | |
| 491 } | |
| 492 } | |
| 493 | |
| 494 | |
| 495 //////////////////////////////////////////////// | |
| 496 // ask a dns question and get an A record answer - we don't try | |
| 497 // very hard, just using the default resolver retry settings. | |
| 498 // If we cannot get an answer, we just accept the mail. | |
| 499 // | |
| 500 // | |
| 501 int dns_interface(mlfiPriv &priv, char *question, bool maybe_ip, ns_map *nameservers); | |
| 502 int dns_interface(mlfiPriv &priv, char *question, bool maybe_ip, ns_map *nameservers) { | |
| 503 // this part can be done without locking the resolver mutex. Each | |
| 504 // milter thread is talking over its own socket to a separate resolver | |
| 505 // process, which does the actual dns resolution. | |
| 506 if (priv.err) return 0; // cannot ask more questions on this socket. | |
| 134 | 507 if (maybe_ip) { |
| 508 // might be a bare ip address, try this first to avoid dns lookups that may not be needed | |
| 509 in_addr ip; | |
| 510 if (inet_aton(question, &ip)) { | |
| 511 return (int)ip.s_addr; | |
| 512 } | |
| 513 } | |
| 514 int n = strlen(question); | |
| 515 if (question[n-1] == '.') { | |
| 516 priv.my_write(question, n+1); // write the question including the null terminator | |
| 517 } | |
| 518 else { | |
| 519 priv.my_write(question, n); // write the question | |
| 520 priv.my_write(".", 2); // and the fully qualified . terminator and null string terminator | |
| 521 } | |
| 94 | 522 glommer glom; |
| 523 char *buf = (char *)&glom; | |
| 524 priv.my_read(buf, sizeof(glom.length)); | |
| 525 buf += sizeof(glom.length); | |
| 526 #ifdef RESOLVER_DEBUG | |
| 527 char text[1000]; | |
| 528 snprintf(text, sizeof(text), "dns_interface() wrote question %s and has answer length %d", question, glom.length); | |
| 529 my_syslog(text); | |
| 530 #endif | |
| 531 if ((glom.length < 0) || (glom.length > sizeof(glom.answer))) { | |
| 532 priv.err = true; | |
| 533 return 0; // cannot process overlarge answers | |
| 534 } | |
| 535 priv.my_read(buf, glom.length); | |
| 536 | |
| 537 #ifdef NS_PACKETSZ | |
| 538 // now we need to lock the resolver mutex to keep the milter threads from | |
| 539 // stepping on each other while parsing the dns answer. | |
| 540 int ret_address = 0; | |
| 541 pthread_mutex_lock(&resolve_mutex); | |
| 542 if (glom.length > 0) { | |
| 543 // parse the answer | |
| 544 ns_msg handle; | |
| 545 ns_rr rr; | |
| 546 if (ns_initparse(glom.answer, glom.length, &handle) == 0) { | |
| 547 // look for ns names | |
| 548 if (nameservers) { | |
| 549 ns_map &ns = *nameservers; | |
| 550 int rrnum = 0; | |
| 551 while (ns_parserr(&handle, ns_s_ns, rrnum++, &rr) == 0) { | |
| 552 if (ns_rr_type(rr) == ns_t_ns) { | |
| 553 char nam[NS_MAXDNAME+1]; | |
| 554 char *n = nam; | |
| 555 const u_char *p = ns_rr_rdata(rr); | |
| 556 while (((n-nam) < NS_MAXDNAME) && ((p-glom.answer) < glom.length) && *p) { | |
| 557 size_t s = *(p++); | |
| 558 if (s > 191) { | |
| 559 // compression pointer | |
| 560 s = (s-192)*256 + *(p++); | |
| 561 if (s >= glom.length) break; // pointer outside bounds of answer | |
| 562 p = glom.answer + s; | |
| 563 s = *(p++); | |
| 564 } | |
| 565 if (s > 0) { | |
| 566 if ((n-nam) >= (NS_MAXDNAME-s)) break; // destination would overflow name buffer | |
| 567 if ((p-glom.answer) >= (glom.length-s)) break; // source outside bounds of answer | |
| 568 memcpy(n, p, s); | |
| 569 n += s; | |
| 570 p += s; | |
| 571 *(n++) = '.'; | |
| 572 } | |
| 573 } | |
| 574 if (n-nam) n--; // remove trailing . | |
| 575 *n = '\0'; // null terminate it | |
| 576 ns.add(nam, question); // ns host to lookup later | |
| 577 } | |
| 578 } | |
| 579 rrnum = 0; | |
| 580 while (ns_parserr(&handle, ns_s_ar, rrnum++, &rr) == 0) { | |
| 581 if (ns_rr_type(rr) == ns_t_a) { | |
| 582 char* nam = (char*)ns_rr_name(rr); | |
| 583 ns_mapper::iterator i = ns.ns_ip.find(nam); | |
| 584 if (i != ns.ns_ip.end()) { | |
| 585 // we want this ip address | |
| 586 int address; | |
| 587 memcpy(&address, ns_rr_rdata(rr), sizeof(address)); | |
| 588 ns.ns_ip[nam] = address; | |
| 589 } | |
| 590 } | |
| 591 } | |
| 592 } | |
| 593 int rrnum = 0; | |
| 594 while (ns_parserr(&handle, ns_s_an, rrnum++, &rr) == 0) { | |
| 595 if (ns_rr_type(rr) == ns_t_a) { | |
| 596 int address; | |
| 597 memcpy(&address, ns_rr_rdata(rr), sizeof(address)); | |
| 598 ret_address = address; | |
| 599 } | |
| 600 } | |
| 601 } | |
| 602 } | |
| 603 pthread_mutex_unlock(&resolve_mutex); | |
| 604 return ret_address; | |
| 605 #else | |
| 606 return glom.answer; | |
| 607 #endif | |
| 608 } | |
| 609 | |
| 610 | |
| 611 //////////////////////////////////////////////// | |
| 612 // check a single dnsbl | |
| 613 // | |
| 614 bool check_single(mlfiPriv &priv, int ip, char *suffix); | |
| 615 bool check_single(mlfiPriv &priv, int ip, char *suffix) { | |
| 616 // make a dns question | |
| 617 const u_char *src = (const u_char *)&ip; | |
| 618 if (src[0] == 127) return false; // don't do dns lookups on localhost | |
| 126 | 619 if (src[0] == 10) return false; // don't do dns lookups on rfc1918 space |
| 620 if ((src[0] == 192) && (src[1] == 168)) return false; | |
| 621 if ((src[0] == 172) && (16 <= src[1]) && (src[1] <= 31)) return false; | |
| 94 | 622 #ifdef NS_MAXDNAME |
| 623 char question[NS_MAXDNAME]; | |
| 624 #else | |
| 625 char question[1000]; | |
| 626 #endif | |
| 627 snprintf(question, sizeof(question), "%u.%u.%u.%u.%s.", src[3], src[2], src[1], src[0], suffix); | |
| 628 // ask the question, if we get an A record it implies a blacklisted ip address | |
| 629 return dns_interface(priv, question, false, NULL); | |
| 630 } | |
| 631 | |
| 632 | |
| 633 //////////////////////////////////////////////// | |
| 634 // check a single dnsbl | |
| 635 // | |
| 636 bool check_single(mlfiPriv &priv, int ip, DNSBL &bl); | |
| 637 bool check_single(mlfiPriv &priv, int ip, DNSBL &bl) { | |
| 638 return check_single(priv, ip, bl.suffix); | |
| 639 } | |
| 640 | |
| 641 | |
| 642 //////////////////////////////////////////////// | |
| 643 // check the dnsbls specified for this recipient | |
| 644 // | |
| 645 bool check_dnsbl(mlfiPriv &priv, dnsblp_list &dnsbll, DNSBLP &rejectlist); | |
| 646 bool check_dnsbl(mlfiPriv &priv, dnsblp_list &dnsbll, DNSBLP &rejectlist) { | |
| 647 for (dnsblp_list::iterator i=dnsbll.begin(); i!=dnsbll.end(); i++) { | |
| 648 DNSBLP dp = *i; // non null by construction | |
| 649 bool st; | |
| 650 map<DNSBLP, bool>::iterator f = priv.checked.find(dp); | |
| 651 if (f == priv.checked.end()) { | |
| 652 // have not checked this list yet | |
| 653 st = check_single(priv, priv.ip, *dp); | |
| 654 rejectlist = dp; | |
| 655 priv.checked[dp] = st; | |
| 656 } | |
| 657 else { | |
| 658 st = (*f).second; | |
| 659 rejectlist = (*f).first; | |
| 660 } | |
| 661 if (st) return st; | |
| 662 } | |
| 663 return false; | |
| 664 } | |
| 665 | |
| 666 | |
| 667 //////////////////////////////////////////////// | |
| 134 | 668 // lookup the domain name part of a hostname on the uribl |
| 117 | 669 // |
| 124 | 670 // if we find part of the hostname on the uribl, return |
| 671 // true and point found to the part of the hostname that we found. | |
| 672 // otherwise, return false and preserve the value of found. | |
| 673 // | |
| 674 bool uriblookup(mlfiPriv &priv ,char *hostname, char *top, char *&found) ; | |
| 675 bool uriblookup(mlfiPriv &priv, char *hostname, char *top, char *&found) { | |
| 117 | 676 // top is pointer to '.' char at end of base domain, or null for ip address form |
| 677 // so for hostname of www.fred.mydomain.co.uk | |
| 678 // top points to-----------------------^ | |
| 679 // and we end up looking at only mydomain.co.uk, ignoring the www.fred stuff | |
| 680 char buf[maxlen]; | |
| 681 if (top) { | |
| 682 // add one more component | |
| 683 *top = '\0'; | |
| 684 char *x = strrchr(hostname, '.'); | |
| 685 if (x) hostname = x+1; | |
| 686 *top = '.'; | |
| 687 } | |
|
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uribl lookups fully qualified; allow two component host names
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|
688 snprintf(buf, sizeof(buf), "%s.%s.", hostname, priv.uribl_suffix); |
| 119 | 689 if (dns_interface(priv, buf, false, NULL)) { |
| 117 | 690 if (debug_syslog > 2) { |
| 691 char tmp[maxlen]; | |
| 119 | 692 snprintf(tmp, sizeof(tmp), "found %s on %s", hostname, priv.uribl_suffix); |
| 117 | 693 my_syslog(tmp); |
| 694 } | |
| 124 | 695 found = hostname; |
| 119 | 696 return true; |
| 117 | 697 } |
| 698 return false; | |
| 699 } | |
| 700 | |
| 701 | |
| 702 //////////////////////////////////////////////// | |
| 124 | 703 // uribl checker |
| 704 // ------------- | |
| 705 // hostname MUST not have a trailing dot | |
| 706 // If tld, two level lookup. | |
| 707 // Else, look up three level domain. | |
| 708 // | |
| 709 // if we find part of the hostname on the uribl, return | |
| 710 // true and point found to the part of the hostname that we found. | |
| 711 // otherwise, return false and preserve the value of found. | |
| 712 // | |
| 713 bool check_uribl(mlfiPriv &priv, char *hostname, char *&found) ; | |
| 714 bool check_uribl(mlfiPriv &priv, char *hostname, char *&found) { | |
| 117 | 715 in_addr ip; |
| 716 if (inet_aton(hostname, &ip)) { | |
| 120 | 717 const u_char *src = (const u_char *)&ip.s_addr; |
| 128 | 718 if (src[0] == 127) return false; // don't do dns lookups on localhost |
| 719 if (src[0] == 10) return false; // don't do dns lookups on rfc1918 space | |
| 720 if ((src[0] == 192) && (src[1] == 168)) return false; | |
| 721 if ((src[0] == 172) && (16 <= src[1]) && (src[1] <= 31)) return false; | |
| 124 | 722 static char adr[sizeof "255.255.255.255"]; |
| 120 | 723 snprintf(adr, sizeof(adr), "%u.%u.%u.%u", src[3], src[2], src[1], src[0]); |
| 124 | 724 return (uriblookup(priv, adr, NULL, found)); |
| 117 | 725 } |
| 726 | |
| 727 char *top, *top2, *top3; | |
| 728 top = strrchr(hostname, '.'); | |
| 729 if (top) { | |
| 730 *top = '\0'; | |
| 731 top2 = strrchr(hostname, '.'); | |
| 732 *top = '.'; | |
| 733 | |
| 734 if (top2) { | |
| 735 string_set::iterator i = priv.memory->get_cctlds()->find(top2+1); | |
| 736 string_set::iterator x = priv.memory->get_cctlds()->end(); | |
| 737 // if we have a 2-level-cctld, just look at top three levels of the name | |
| 124 | 738 if (i != x) return uriblookup(priv, hostname, top2, found); |
| 117 | 739 |
| 740 *top2 = '\0'; | |
| 741 top3 = strrchr(hostname, '.'); | |
| 742 *top2 = '.'; | |
| 743 | |
| 744 // if we have more than 3 levels in the name, look at the top three levels of the name | |
| 124 | 745 if (top3 && uriblookup(priv, hostname, top2, found)) return true; |
| 117 | 746 // if that was not found, fall thru to looking at the top two levels |
| 747 } | |
| 748 // look at the top two levels of the name | |
| 124 | 749 return uriblookup(priv, hostname, top, found); |
| 117 | 750 } |
| 751 return false; | |
| 752 } | |
| 753 | |
| 754 | |
| 755 //////////////////////////////////////////////// | |
| 119 | 756 // check the hosts from the body against the content filter and uribl dnsbls |
| 94 | 757 // |
| 124 | 758 // |
| 759 bool check_hosts(mlfiPriv &priv, bool random, int limit, char *&msg, char *&host, int &ip, char *&found); | |
| 760 bool check_hosts(mlfiPriv &priv, bool random, int limit, char *&msg, char *&host, int &ip, char *&found) { | |
| 761 found = NULL; // normally ip address style | |
| 119 | 762 if (!priv.content_suffix && !priv.uribl_suffix) return false; // nothing to check |
| 94 | 763 CONFIG &dc = *priv.pc; |
| 764 string_set &hosts = priv.memory->get_hosts(); | |
| 765 string_set &ignore = *priv.content_host_ignore; | |
| 766 | |
| 767 int count = 0; | |
| 768 int cnt = hosts.size(); // number of hosts we could look at | |
| 769 int_set ips; | |
| 770 ns_map nameservers; | |
| 771 for (string_set::iterator i=hosts.begin(); i!=hosts.end(); i++) { | |
| 772 host = *i; // a reference into hosts, which will live until this smtp transaction is closed | |
| 773 | |
| 774 // don't bother looking up hosts on the ignore list | |
| 775 string_set::iterator j = ignore.find(host); | |
| 776 if (j != ignore.end()) continue; | |
| 777 | |
| 778 // try to only look at limit/cnt fraction of the available cnt host names in random mode | |
| 779 if ((cnt > limit) && (limit > 0) && random) { | |
| 780 int r = rand() % cnt; | |
| 781 if (r >= limit) { | |
| 782 if (debug_syslog > 2) { | |
| 783 char buf[maxlen]; | |
| 784 snprintf(buf, sizeof(buf), "host %s skipped", host); | |
| 785 my_syslog(&priv, buf); | |
| 786 } | |
| 787 continue; | |
| 788 } | |
| 789 } | |
| 790 count++; | |
| 791 ip = dns_interface(priv, host, true, &nameservers); | |
| 792 if (debug_syslog > 2) { | |
| 793 char buf[maxlen]; | |
| 794 if (ip) { | |
| 795 char adr[sizeof "255.255.255.255"]; | |
| 796 adr[0] = '\0'; | |
| 797 inet_ntop(AF_INET, (const u_char *)&ip, adr, sizeof(adr)); | |
| 798 snprintf(buf, sizeof(buf), "host %s found at %s", host, adr); | |
| 799 } | |
| 800 else { | |
| 801 snprintf(buf, sizeof(buf), "host %s not found", host); | |
| 802 } | |
| 803 my_syslog(&priv, buf); | |
| 804 } | |
| 805 if (ip) { | |
| 806 int_set::iterator i = ips.find(ip); | |
| 807 if (i == ips.end()) { | |
| 117 | 808 // we haven't looked this up yet |
| 94 | 809 ips.insert(ip); |
| 124 | 810 // check dnsbl style list |
| 811 if (priv.content_suffix && check_single(priv, ip, priv.content_suffix)) { | |
| 119 | 812 msg = priv.content_message; |
| 813 return true; | |
| 814 } | |
| 124 | 815 // Check uribl & surbl style list |
| 816 if (priv.uribl_suffix && check_uribl(priv, host, found)) { | |
| 119 | 817 msg = priv.uribl_message; |
| 818 return true; | |
| 819 } | |
| 94 | 820 } |
| 821 } | |
| 822 } | |
| 823 limit *= 4; // allow average of 3 ns per host name | |
| 824 for (ns_mapper::iterator i=nameservers.ns_ip.begin(); i!=nameservers.ns_ip.end(); i++) { | |
| 825 count++; | |
| 119 | 826 if ((count > limit) && (limit > 0)) return false; // too many name servers to check them all |
| 94 | 827 host = (*i).first; // a transient reference that needs to be replaced before we return it |
| 828 ip = (*i).second; | |
| 829 if (!ip) ip = dns_interface(priv, host, false, NULL); | |
| 830 if (debug_syslog > 2) { | |
| 831 char buf[maxlen]; | |
| 832 if (ip) { | |
| 833 char adr[sizeof "255.255.255.255"]; | |
| 834 adr[0] = '\0'; | |
| 835 inet_ntop(AF_INET, (const u_char *)&ip, adr, sizeof(adr)); | |
| 836 snprintf(buf, sizeof(buf), "ns %s found at %s", host, adr); | |
| 837 } | |
| 838 else { | |
| 839 snprintf(buf, sizeof(buf), "ns %s not found", host); | |
| 840 } | |
| 841 my_syslog(&priv, buf); | |
| 842 } | |
| 843 if (ip) { | |
| 844 int_set::iterator i = ips.find(ip); | |
| 845 if (i == ips.end()) { | |
| 846 ips.insert(ip); | |
| 119 | 847 if (check_single(priv, ip, priv.content_suffix)) { |
| 848 msg = priv.content_message; | |
| 94 | 849 string_map::iterator j = nameservers.ns_host.find(host); |
| 850 if (j != nameservers.ns_host.end()) { | |
| 851 char *refer = (*j).second; | |
| 852 char buf[maxlen]; | |
| 853 snprintf(buf, sizeof(buf), "%s with nameserver %s", refer, host); | |
| 854 host = register_string(hosts, buf); // put a copy into hosts, and return that reference | |
| 855 } | |
| 856 else { | |
| 857 host = register_string(hosts, host); // put a copy into hosts, and return that reference | |
| 858 } | |
| 859 return true; | |
| 860 } | |
| 861 } | |
| 862 } | |
| 863 } | |
| 864 return false; | |
| 865 } | |
| 866 | |
| 127 | 867 |
| 94 | 868 //////////////////////////////////////////////// |
| 127 | 869 // |
| 870 // this email address is passed in from sendmail, and will normally be | |
| 871 // enclosed in <>. I think older versions of sendmail supplied the <> | |
| 872 // wrapper if the mail client did not, but the current version does not do | |
| 873 // that. So the <> wrapper is now optional. It may have mixed case, just | |
| 874 // as the mail client sent it. We dup the string and convert the duplicate | |
| 875 // to lower case. | |
| 94 | 876 // |
| 877 char *to_lower_string(char *email); | |
| 878 char *to_lower_string(char *email) { | |
| 127 | 879 int n = strlen(email); |
| 880 if (*email == '<') { | |
| 881 // assume it also ends with > | |
| 882 n -= 2; | |
| 883 if (n < 1) return strdup(email); // return "<>" | |
| 884 email++; | |
| 885 } | |
| 886 char *key = strdup(email); | |
| 94 | 887 key[n] = '\0'; |
| 888 for (int i=0; i<n; i++) key[i] = tolower(key[i]); | |
| 889 return key; | |
| 890 } | |
| 891 | |
| 892 | |
| 893 //////////////////////////////////////////////// | |
| 894 // start of sendmail milter interfaces | |
| 895 // | |
| 896 sfsistat mlfi_connect(SMFICTX *ctx, char *hostname, _SOCK_ADDR *hostaddr) | |
| 897 { | |
| 898 // allocate some private memory | |
| 899 mlfiPriv *priv = new mlfiPriv; | |
| 900 if (hostaddr->sa_family == AF_INET) { | |
| 901 priv->ip = ((struct sockaddr_in *)hostaddr)->sin_addr.s_addr; | |
| 902 } | |
| 903 | |
| 904 // save the private data | |
| 905 smfi_setpriv(ctx, (void*)priv); | |
| 906 | |
| 907 // continue processing | |
| 908 return SMFIS_CONTINUE; | |
| 909 } | |
| 910 | |
| 911 sfsistat mlfi_envfrom(SMFICTX *ctx, char **from) | |
| 912 { | |
| 913 mlfiPriv &priv = *MLFIPRIV; | |
| 914 priv.mailaddr = to_lower_string(from[0]); | |
| 915 priv.authenticated = (smfi_getsymval(ctx, "{auth_authen}") != NULL); | |
| 916 return SMFIS_CONTINUE; | |
| 917 } | |
| 918 | |
| 919 sfsistat mlfi_envrcpt(SMFICTX *ctx, char **rcpt) | |
| 920 { | |
| 921 DNSBLP rejectlist = NULL; // list that caused the reject | |
| 922 mlfiPriv &priv = *MLFIPRIV; | |
| 923 CONFIG &dc = *priv.pc; | |
| 924 if (!priv.queueid) priv.queueid = strdup(smfi_getsymval(ctx, "i")); | |
| 925 char *rcptaddr = rcpt[0]; | |
| 926 char *loto = to_lower_string(rcptaddr); | |
| 927 CONTEXT &con = *(dc.find_context(loto)->find_context(priv.mailaddr)); | |
| 928 VERIFYP ver = con.find_verify(loto); | |
| 929 if (debug_syslog > 1) { | |
| 930 char buf[maxlen]; | |
| 931 char msg[maxlen]; | |
| 932 snprintf(msg, sizeof(msg), "from <%s> to <%s> using context %s", priv.mailaddr, loto, con.get_full_name(buf,maxlen)); | |
| 933 my_syslog(&priv, msg); | |
| 934 } | |
| 935 free(loto); | |
| 936 char *fromvalue = con.find_from(priv.mailaddr); | |
| 937 status st; | |
| 938 if (priv.authenticated) { | |
| 939 st = white; | |
| 940 } | |
| 941 else if (fromvalue == token_black) { | |
| 942 st = black; | |
| 943 } | |
| 944 else if (fromvalue == token_white) { | |
| 945 st = white; | |
| 946 } | |
| 947 else { | |
| 948 // check the dns based lists | |
| 949 st = (check_dnsbl(priv, con.get_dnsbl_list(), rejectlist)) ? reject : oksofar; | |
| 950 } | |
| 951 if (st == reject) { | |
| 952 // reject the recipient based on some dnsbl | |
| 953 char adr[sizeof "255.255.255.255"]; | |
| 954 adr[0] = '\0'; | |
| 955 inet_ntop(AF_INET, (const u_char *)&priv.ip, adr, sizeof(adr)); | |
| 956 char buf[maxlen]; | |
| 957 snprintf(buf, sizeof(buf), rejectlist->message, adr, adr); | |
| 958 smfi_setreply(ctx, "550", "5.7.1", buf); | |
| 959 return SMFIS_REJECT; | |
| 960 } | |
| 961 if (st == black) { | |
| 962 // reject the recipient based on blacklisting either from or to | |
| 963 smfi_setreply(ctx, "550", "5.7.1", "no such user"); | |
| 964 return SMFIS_REJECT; | |
| 965 } | |
| 966 if (ver && (st != white)) { | |
| 967 // try to verify this from/to pair of addresses since it is not explicitly whitelisted | |
| 968 char *loto = to_lower_string(rcptaddr); | |
| 969 bool rc = ver->ok(priv.mailaddr, loto); | |
| 970 free(loto); | |
| 971 if (!rc) { | |
| 972 smfi_setreply(ctx, "550", "5.7.1", "no such user"); | |
| 973 return SMFIS_REJECT; | |
| 974 } | |
| 975 } | |
| 976 // accept the recipient | |
| 977 if (!con.get_content_filtering()) st = white; | |
| 978 if (st == oksofar) { | |
| 979 // but remember the non-whites | |
| 980 priv.need_content_filter(rcptaddr, con); | |
| 981 priv.only_whites = false; | |
| 982 } | |
| 983 if (st == white) { | |
| 984 priv.have_whites = true; | |
| 985 } | |
| 986 return SMFIS_CONTINUE; | |
| 987 } | |
| 988 | |
| 989 sfsistat mlfi_body(SMFICTX *ctx, u_char *data, size_t len) | |
| 990 { | |
| 991 mlfiPriv &priv = *MLFIPRIV; | |
| 992 if (priv.authenticated) return SMFIS_CONTINUE; | |
| 993 if (priv.only_whites) return SMFIS_CONTINUE; | |
| 994 priv.scanner->scan(data, len); | |
| 995 return SMFIS_CONTINUE; | |
| 996 } | |
| 997 | |
| 998 sfsistat mlfi_eom(SMFICTX *ctx) | |
| 999 { | |
| 1000 sfsistat rc; | |
| 1001 mlfiPriv &priv = *MLFIPRIV; | |
| 1002 CONFIG &dc = *priv.pc; | |
| 1003 char *host = NULL; | |
| 1004 int ip; | |
| 1005 status st; | |
| 1006 // process end of message | |
| 1007 if (priv.authenticated || priv.only_whites) rc = SMFIS_CONTINUE; | |
| 1008 else { | |
| 1009 // assert env_to not empty | |
| 1010 char buf[maxlen]; | |
| 1011 char *msg = NULL; | |
| 1012 string_set alive; | |
| 1013 bool random = false; | |
| 1014 int limit = 0; | |
| 1015 for (context_map::iterator i=priv.env_to.begin(); i!=priv.env_to.end(); i++) { | |
| 1016 char *rcpt = (*i).first; | |
| 1017 CONTEXT &con = *((*i).second); | |
| 1018 if (!con.acceptable_content(*priv.memory, msg)) { | |
| 1019 // bad html tags or excessive hosts | |
| 1020 smfi_delrcpt(ctx, rcpt); | |
| 1021 } | |
| 1022 else { | |
| 1023 alive.insert(rcpt); | |
| 1024 random |= con.get_host_random(); | |
| 1025 limit = max(limit, con.get_host_limit()); | |
| 1026 } | |
| 1027 } | |
| 1028 bool rejecting = alive.empty(); // if alive is empty, we must have set msg above in acceptable_content() | |
| 1029 if (!rejecting) { | |
| 124 | 1030 char *fmt, *found; |
| 1031 if (check_hosts(priv, random, limit, fmt, host, ip, found)) { | |
| 1032 if (found) { | |
| 1033 // uribl style | |
| 1034 snprintf(buf, sizeof(buf), fmt, host, found); | |
| 1035 } | |
| 1036 else { | |
| 1037 // dnsbl style | |
| 1038 char adr[sizeof "255.255.255.255"]; | |
| 1039 adr[0] = '\0'; | |
| 1040 inet_ntop(AF_INET, (const u_char *)&ip, adr, sizeof(adr)); | |
| 1041 snprintf(buf, sizeof(buf), fmt, host, adr); | |
| 1042 } | |
| 94 | 1043 msg = buf; |
| 1044 rejecting = true; | |
| 1045 } | |
| 1046 } | |
| 1047 if (!rejecting) { | |
| 1048 rc = SMFIS_CONTINUE; | |
| 1049 } | |
| 1050 else if (!priv.have_whites) { | |
| 1051 // can reject the entire message | |
| 1052 smfi_setreply(ctx, "550", "5.7.1", msg); | |
| 1053 rc = SMFIS_REJECT; | |
| 1054 } | |
| 1055 else { | |
| 1056 // need to accept it but remove the recipients that don't want it | |
| 1057 for (string_set::iterator i=alive.begin(); i!=alive.end(); i++) { | |
| 1058 char *rcpt = *i; | |
| 1059 smfi_delrcpt(ctx, rcpt); | |
| 1060 } | |
| 1061 rc = SMFIS_CONTINUE; | |
| 1062 } | |
| 1063 } | |
| 1064 // reset for a new message on the same connection | |
| 1065 mlfi_abort(ctx); | |
| 1066 return rc; | |
| 1067 } | |
| 1068 | |
| 1069 sfsistat mlfi_abort(SMFICTX *ctx) | |
| 1070 { | |
| 1071 mlfiPriv &priv = *MLFIPRIV; | |
| 1072 priv.reset(); | |
| 1073 return SMFIS_CONTINUE; | |
| 1074 } | |
| 1075 | |
| 1076 sfsistat mlfi_close(SMFICTX *ctx) | |
| 1077 { | |
| 1078 mlfiPriv *priv = MLFIPRIV; | |
| 1079 if (!priv) return SMFIS_CONTINUE; | |
| 1080 delete priv; | |
| 1081 smfi_setpriv(ctx, NULL); | |
| 1082 return SMFIS_CONTINUE; | |
| 1083 } | |
| 1084 | |
| 1085 struct smfiDesc smfilter = | |
| 1086 { | |
| 1087 "DNSBL", // filter name | |
| 1088 SMFI_VERSION, // version code -- do not change | |
| 1089 SMFIF_DELRCPT, // flags | |
| 1090 mlfi_connect, // connection info filter | |
| 1091 NULL, // SMTP HELO command filter | |
| 1092 mlfi_envfrom, // envelope sender filter | |
| 1093 mlfi_envrcpt, // envelope recipient filter | |
| 1094 NULL, // header filter | |
| 1095 NULL, // end of header | |
| 1096 mlfi_body, // body block filter | |
| 1097 mlfi_eom, // end of message | |
| 1098 mlfi_abort, // message aborted | |
| 1099 mlfi_close, // connection cleanup | |
| 1100 }; | |
| 1101 | |
| 1102 | |
| 1103 //////////////////////////////////////////////// | |
| 1104 // reload the config | |
| 1105 // | |
| 1106 CONFIG* new_conf(); | |
| 1107 CONFIG* new_conf() { | |
| 1108 CONFIG *newc = new CONFIG; | |
| 1109 pthread_mutex_lock(&config_mutex); | |
| 1110 newc->generation = generation++; | |
| 1111 pthread_mutex_unlock(&config_mutex); | |
| 1112 if (debug_syslog) { | |
| 1113 char buf[maxlen]; | |
| 1114 snprintf(buf, sizeof(buf), "loading configuration generation %d", newc->generation); | |
| 1115 my_syslog(buf); | |
| 1116 } | |
| 1117 if (load_conf(*newc, "dnsbl.conf")) { | |
| 1118 newc->load_time = time(NULL); | |
| 1119 return newc; | |
| 1120 } | |
| 1121 delete newc; | |
| 1122 return NULL; | |
| 1123 } | |
| 1124 | |
| 1125 | |
| 1126 //////////////////////////////////////////////// | |
| 1127 // thread to watch the old config files for changes | |
| 1128 // and reload when needed. we also cleanup old | |
| 1129 // configs whose reference count has gone to zero. | |
| 1130 // | |
| 1131 void* config_loader(void *arg); | |
| 1132 void* config_loader(void *arg) { | |
| 1133 typedef set<CONFIG *> configp_set; | |
| 1134 configp_set old_configs; | |
| 1135 while (loader_run) { | |
| 1136 sleep(180); // look for modifications every 3 minutes | |
| 1137 if (!loader_run) break; | |
| 1138 CONFIG &dc = *config; | |
| 1139 time_t then = dc.load_time; | |
| 1140 struct stat st; | |
| 1141 bool reload = false; | |
| 1142 for (string_set::iterator i=dc.config_files.begin(); i!=dc.config_files.end(); i++) { | |
| 1143 char *fn = *i; | |
| 1144 if (stat(fn, &st)) reload = true; // file disappeared | |
| 1145 else if (st.st_mtime > then) reload = true; // file modified | |
| 1146 if (reload) break; | |
| 1147 } | |
| 1148 if (reload) { | |
| 1149 CONFIG *newc = new_conf(); | |
| 1150 if (newc) { | |
| 1151 // replace the global config pointer | |
| 1152 pthread_mutex_lock(&config_mutex); | |
| 1153 CONFIG *old = config; | |
| 1154 config = newc; | |
| 1155 pthread_mutex_unlock(&config_mutex); | |
| 1156 if (old) old_configs.insert(old); | |
| 1157 } | |
| 1158 else { | |
| 1159 // failed to load new config | |
| 1160 my_syslog("failed to load new configuration"); | |
| 1161 system("echo 'failed to load new dnsbl configuration from /etc/dnsbl' | mail -s 'error in /etc/dnsbl configuration' root"); | |
| 1162 // update the load time on the current config to prevent complaining every 3 minutes | |
| 1163 dc.load_time = time(NULL); | |
| 1164 } | |
| 1165 } | |
| 1166 // now look for old configs with zero ref counts | |
| 1167 for (configp_set::iterator i=old_configs.begin(); i!=old_configs.end(); ) { | |
| 1168 CONFIG *old = *i; | |
| 1169 if (!old->reference_count) { | |
| 1170 if (debug_syslog) { | |
| 1171 char buf[maxlen]; | |
| 1172 snprintf(buf, sizeof(buf), "freeing memory for old configuration generation %d", old->generation); | |
| 1173 my_syslog(buf); | |
| 1174 } | |
| 1175 delete old; // destructor does all the work | |
| 1176 old_configs.erase(i++); | |
| 1177 } | |
| 1178 else i++; | |
| 1179 } | |
| 1180 } | |
| 1181 return NULL; | |
| 1182 } | |
| 1183 | |
| 1184 | |
| 1185 void usage(char *prog); | |
| 1186 void usage(char *prog) | |
| 1187 { | |
| 1188 fprintf(stderr, "Usage: %s [-d [level]] [-c] [-s] [-e from|to] -r port -p sm-sock-addr [-t timeout]\n", prog); | |
| 1189 fprintf(stderr, "where port is for the connection to our own dns resolver processes\n"); | |
| 1190 fprintf(stderr, " and should be local-domain-socket-file-name\n"); | |
| 1191 fprintf(stderr, "where sm-sock-addr is for the connection to sendmail\n"); | |
| 1192 fprintf(stderr, " and should be one of\n"); | |
| 1193 fprintf(stderr, " inet:port@ip-address\n"); | |
| 1194 fprintf(stderr, " local:local-domain-socket-file-name\n"); | |
| 1195 fprintf(stderr, "-c will load and dump the config to stdout\n"); | |
| 1196 fprintf(stderr, "-s will stress test the config loading code by repeating the load/free cycle\n"); | |
| 1197 fprintf(stderr, " in an infinte loop.\n"); | |
| 1198 fprintf(stderr, "-d will set the syslog message level, currently 0 to 3\n"); | |
| 1199 fprintf(stderr, "-e will print the results of looking up the from and to addresses in the\n"); | |
| 1200 fprintf(stderr, " current config. The | character is used to separate the from and to\n"); | |
| 1201 fprintf(stderr, " addresses in the argument to the -e switch\n"); | |
| 1202 } | |
| 1203 | |
| 1204 | |
| 1205 | |
| 1206 void setup_socket(char *sock); | |
| 1207 void setup_socket(char *sock) { | |
| 1208 unlink(sock); | |
| 1209 // sockaddr_un addr; | |
| 1210 // memset(&addr, '\0', sizeof addr); | |
| 1211 // addr.sun_family = AF_UNIX; | |
| 1212 // strncpy(addr.sun_path, sock, sizeof(addr.sun_path)-1); | |
| 1213 // int s = socket(AF_UNIX, SOCK_STREAM, 0); | |
| 1214 // bind(s, (sockaddr*)&addr, sizeof(addr)); | |
| 1215 // close(s); | |
| 1216 } | |
| 1217 | |
| 1218 | |
| 1219 /* | |
| 1220 * The signal handler function -- only gets called when a SIGCHLD | |
| 1221 * is received, ie when a child terminates | |
| 1222 */ | |
| 1223 void sig_chld(int signo) | |
| 1224 { | |
| 1225 int status; | |
| 1226 /* Wait for any child without blocking */ | |
| 1227 while (waitpid(-1, &status, WNOHANG) > 0) { | |
| 1228 // ignore child exit status, we only do this to cleanup zombies | |
| 1229 } | |
| 1230 } | |
| 1231 | |
| 1232 | |
| 1233 int main(int argc, char**argv) | |
| 1234 { | |
| 1235 token_init(); | |
| 1236 bool check = false; | |
| 1237 bool stress = false; | |
| 1238 bool setconn = false; | |
| 1239 bool setreso = false; | |
| 1240 char *email = NULL; | |
| 1241 int c; | |
| 1242 const char *args = "r:p:t:e:d:chs"; | |
| 1243 extern char *optarg; | |
| 1244 | |
| 1245 // Process command line options | |
| 1246 while ((c = getopt(argc, argv, args)) != -1) { | |
| 1247 switch (c) { | |
| 1248 case 'r': | |
| 1249 if (optarg == NULL || *optarg == '\0') { | |
| 1250 fprintf(stderr, "Illegal resolver socket: %s\n", optarg); | |
| 1251 exit(EX_USAGE); | |
| 1252 } | |
| 1253 resolver_port = strdup(optarg); | |
| 1254 setup_socket(resolver_port); | |
| 1255 setreso = true; | |
| 1256 break; | |
| 1257 | |
| 1258 case 'p': | |
| 1259 if (optarg == NULL || *optarg == '\0') { | |
| 1260 fprintf(stderr, "Illegal sendmail socket: %s\n", optarg); | |
| 1261 exit(EX_USAGE); | |
| 1262 } | |
| 1263 if (smfi_setconn(optarg) == MI_FAILURE) { | |
| 1264 fprintf(stderr, "smfi_setconn failed\n"); | |
| 1265 exit(EX_SOFTWARE); | |
| 1266 } | |
| 1267 if (strncasecmp(optarg, "unix:", 5) == 0) setup_socket(optarg + 5); | |
| 1268 else if (strncasecmp(optarg, "local:", 6) == 0) setup_socket(optarg + 6); | |
| 1269 setconn = true; | |
| 1270 break; | |
| 1271 | |
| 1272 case 't': | |
| 1273 if (optarg == NULL || *optarg == '\0') { | |
| 1274 fprintf(stderr, "Illegal timeout: %s\n", optarg); | |
| 1275 exit(EX_USAGE); | |
| 1276 } | |
| 1277 if (smfi_settimeout(atoi(optarg)) == MI_FAILURE) { | |
| 1278 fprintf(stderr, "smfi_settimeout failed\n"); | |
| 1279 exit(EX_SOFTWARE); | |
| 1280 } | |
| 1281 break; | |
| 1282 | |
| 1283 case 'e': | |
| 1284 if (email) free(email); | |
| 1285 email = strdup(optarg); | |
| 1286 break; | |
| 1287 | |
| 1288 case 'c': | |
| 1289 check = true; | |
| 1290 break; | |
| 1291 | |
| 1292 case 's': | |
| 1293 stress = true; | |
| 1294 break; | |
| 1295 | |
| 1296 case 'd': | |
| 1297 if (optarg == NULL || *optarg == '\0') debug_syslog = 1; | |
| 1298 else debug_syslog = atoi(optarg); | |
| 1299 break; | |
| 1300 | |
| 1301 case 'h': | |
| 1302 default: | |
| 1303 usage(argv[0]); | |
| 1304 exit(EX_USAGE); | |
| 1305 } | |
| 1306 } | |
| 1307 | |
| 1308 if (check) { | |
| 1309 use_syslog = false; | |
| 1310 debug_syslog = 10; | |
| 1311 CONFIG *conf = new_conf(); | |
| 1312 if (conf) { | |
| 1313 conf->dump(); | |
| 1314 delete conf; | |
| 1315 return 0; | |
| 1316 } | |
| 1317 else { | |
| 1318 return 1; // config failed to load | |
| 1319 } | |
| 1320 } | |
| 1321 | |
| 1322 if (stress) { | |
| 1323 fprintf(stdout, "stress testing\n"); | |
| 1324 while (1) { | |
| 1325 for (int i=0; i<10; i++) { | |
| 1326 CONFIG *conf = new_conf(); | |
| 1327 if (conf) delete conf; | |
| 1328 } | |
| 1329 fprintf(stdout, "."); | |
| 1330 fflush(stdout); | |
| 1331 sleep(1); | |
| 1332 } | |
| 1333 } | |
| 1334 | |
| 1335 if (email) { | |
| 1336 char *x = strchr(email, '|'); | |
| 1337 if (x) { | |
| 1338 *x = '\0'; | |
| 1339 char *from = strdup(email); | |
| 1340 char *to = strdup(x+1); | |
| 1341 use_syslog = false; | |
| 1342 CONFIG *conf = new_conf(); | |
| 1343 if (conf) { | |
| 1344 CONTEXTP con = conf->find_context(to); | |
| 1345 char buf[maxlen]; | |
| 1346 fprintf(stdout, "envelope to <%s> finds context %s\n", to, con->get_full_name(buf,maxlen)); | |
| 1347 CONTEXTP fc = con->find_context(from); | |
| 1348 fprintf(stdout, "envelope from <%s> finds context %s\n", from, fc->get_full_name(buf,maxlen)); | |
| 1349 char *st = fc->find_from(from); | |
| 1350 fprintf(stdout, "envelope from <%s> finds status %s\n", from, st); | |
| 1351 delete conf; | |
| 1352 } | |
| 1353 } | |
| 1354 return 0; | |
| 1355 } | |
| 1356 | |
| 1357 if (!setconn) { | |
| 1358 fprintf(stderr, "%s: Missing required -p argument\n", argv[0]); | |
| 1359 usage(argv[0]); | |
| 1360 exit(EX_USAGE); | |
| 1361 } | |
| 1362 | |
| 1363 if (!setreso) { | |
| 1364 fprintf(stderr, "%s: Missing required -r argument\n", argv[0]); | |
| 1365 usage(argv[0]); | |
| 1366 exit(EX_USAGE); | |
| 1367 } | |
| 1368 | |
| 1369 if (smfi_register(smfilter) == MI_FAILURE) { | |
| 1370 fprintf(stderr, "smfi_register failed\n"); | |
| 1371 exit(EX_UNAVAILABLE); | |
| 1372 } | |
| 1373 | |
| 1374 // switch to background mode | |
| 1375 if (daemon(1,0) < 0) { | |
| 1376 fprintf(stderr, "daemon() call failed\n"); | |
| 1377 exit(EX_UNAVAILABLE); | |
| 1378 } | |
| 1379 | |
| 1380 // write the pid | |
| 1381 const char *pidpath = "/var/run/dnsbl.pid"; | |
| 1382 unlink(pidpath); | |
| 1383 FILE *f = fopen(pidpath, "w"); | |
| 1384 if (f) { | |
| 1385 #ifdef linux | |
| 1386 // from a comment in the DCC source code: | |
| 1387 // Linux threads are broken. Signals given the | |
| 1388 // original process are delivered to only the | |
| 1389 // thread that happens to have that PID. The | |
| 1390 // sendmail libmilter thread that needs to hear | |
| 1391 // SIGINT and other signals does not, and that breaks | |
| 1392 // scripts that need to stop milters. | |
| 1393 // However, signaling the process group works. | |
| 1394 fprintf(f, "-%d\n", (u_int)getpgrp()); | |
| 1395 #else | |
| 1396 fprintf(f, "%d\n", (u_int)getpid()); | |
| 1397 #endif | |
| 1398 fclose(f); | |
| 1399 } | |
| 1400 | |
| 1401 // initialize the thread sync objects | |
| 1402 pthread_mutex_init(&config_mutex, 0); | |
| 1403 pthread_mutex_init(&syslog_mutex, 0); | |
| 1404 pthread_mutex_init(&resolve_mutex, 0); | |
| 1405 pthread_mutex_init(&fd_pool_mutex, 0); | |
| 1406 | |
| 1407 // drop root privs | |
| 1408 struct passwd *pw = getpwnam("dnsbl"); | |
| 1409 if (pw) { | |
| 1410 if (setgid(pw->pw_gid) == -1) { | |
| 1411 my_syslog("failed to switch to group dnsbl"); | |
| 1412 } | |
| 1413 if (setuid(pw->pw_uid) == -1) { | |
| 1414 my_syslog("failed to switch to user dnsbl"); | |
| 1415 } | |
| 1416 } | |
| 1417 | |
| 1418 // load the initial config | |
| 1419 config = new_conf(); | |
| 1420 if (!config) { | |
| 1421 my_syslog("failed to load initial configuration, quitting"); | |
| 1422 exit(1); | |
| 1423 } | |
| 1424 | |
| 1425 // fork off the resolver listener process | |
| 1426 pid_t child = fork(); | |
| 1427 if (child < 0) { | |
| 1428 my_syslog("failed to create resolver listener process"); | |
| 1429 exit(0); | |
| 1430 } | |
| 1431 if (child == 0) { | |
| 1432 // we are the child - dns resolver listener process | |
| 1433 resolver_socket = socket(AF_UNIX, SOCK_STREAM, 0); | |
| 1434 if (resolver_socket < 0) { | |
| 1435 my_syslog("child failed to create resolver socket"); | |
| 1436 exit(0); // failed | |
| 1437 } | |
| 1438 sockaddr_un server; | |
| 1439 memset(&server, '\0', sizeof(server)); | |
| 1440 server.sun_family = AF_UNIX; | |
| 1441 strncpy(server.sun_path, resolver_port, sizeof(server.sun_path)-1); | |
| 1442 //try to bind the address to the socket. | |
| 1443 if (bind(resolver_socket, (sockaddr *)&server, sizeof(server)) < 0) { | |
| 1444 // bind failed | |
| 1445 shutdown(resolver_socket, SHUT_RDWR); | |
| 1446 close(resolver_socket); | |
| 1447 my_syslog("child failed to bind resolver socket"); | |
| 1448 exit(0); // failed | |
| 1449 } | |
| 1450 //listen on the socket. | |
| 1451 if (listen(resolver_socket, 10) < 0) { | |
| 1452 // listen failed | |
| 1453 shutdown(resolver_socket, SHUT_RDWR); | |
| 1454 close(resolver_socket); | |
| 1455 my_syslog("child failed to listen to resolver socket"); | |
| 1456 exit(0); // failed | |
| 1457 } | |
| 1458 // setup sigchld handler to prevent zombies | |
| 1459 struct sigaction act; | |
| 1460 act.sa_handler = sig_chld; // Assign sig_chld as our SIGCHLD handler | |
| 1461 sigemptyset(&act.sa_mask); // We don't want to block any other signals in this example | |
| 1462 act.sa_flags = SA_NOCLDSTOP; // only want children that have terminated | |
| 1463 if (sigaction(SIGCHLD, &act, NULL) < 0) { | |
| 1464 my_syslog("child failed to setup SIGCHLD handler"); | |
| 1465 exit(0); // failed | |
| 1466 } | |
| 1467 while (true) { | |
| 1468 sockaddr_un client; | |
| 1469 socklen_t clientlen = sizeof(client); | |
| 1470 int s = accept(resolver_socket, (sockaddr *)&client, &clientlen); | |
| 1471 if (s > 0) { | |
| 1472 // accept worked, it did not get cancelled before we could accept it | |
| 1473 // fork off a process to handle this connection | |
| 1474 int newchild = fork(); | |
| 1475 if (newchild == 0) { | |
| 1476 // this is the worker process | |
| 1477 // child does not need the listening socket | |
| 1478 close(resolver_socket); | |
| 1479 process_resolver_requests(s); | |
| 1480 exit(0); | |
| 1481 } | |
| 1482 else { | |
| 1483 // this is the parent | |
| 1484 // parent does not need the accepted socket | |
| 1485 close(s); | |
| 1486 } | |
| 1487 } | |
| 1488 } | |
| 1489 exit(0); // make sure we don't fall thru. | |
| 1490 } | |
| 1491 else { | |
| 1492 sleep(2); // allow child to get started | |
| 1493 } | |
| 1494 | |
| 1495 // only create threads after the fork() in daemon | |
| 1496 pthread_t tid; | |
| 1497 if (pthread_create(&tid, 0, config_loader, 0)) | |
| 1498 my_syslog("failed to create config loader thread"); | |
| 1499 if (pthread_detach(tid)) | |
| 1500 my_syslog("failed to detach config loader thread"); | |
| 1501 if (pthread_create(&tid, 0, verify_closer, 0)) | |
| 1502 my_syslog("failed to create verify closer thread"); | |
| 1503 if (pthread_detach(tid)) | |
| 1504 my_syslog("failed to detach verify closer thread"); | |
| 1505 | |
| 1506 time_t starting = time(NULL); | |
| 1507 int rc = smfi_main(); | |
| 1508 if ((rc != MI_SUCCESS) && (time(NULL) > starting+5*60)) { | |
| 1509 my_syslog("trying to restart after smfi_main()"); | |
| 1510 loader_run = false; // eventually the config loader thread will terminate | |
| 1511 execvp(argv[0], argv); | |
| 1512 } | |
| 1513 exit((rc == MI_SUCCESS) ? 0 : EX_UNAVAILABLE); | |
| 1514 } | |
| 1515 |