mdw@git.distorted.org.uk Git - qmail/blob - qmail-smtpd.c

   1 #include "sig.h"
   2 #include "readwrite.h"
   3 #include "stralloc.h"
   4 #include "substdio.h"
   5 #include "alloc.h"
   6 #include "auto_qmail.h"
   7 #include "control.h"
   8 #include "received.h"
   9 #include "constmap.h"
  10 #include "error.h"
  11 #include "ipme.h"
  12 #include "ip.h"
  13 #include "qmail.h"
  14 #include "str.h"
  15 #include "fmt.h"
  16 #include "scan.h"
  17 #include "byte.h"
  18 #include "case.h"
  19 #include "env.h"
  20 #include "now.h"
  21 #include "exit.h"
  22 #include "rcpthosts.h"
  23 #include "addrcheck.h"
  24 #include "timeoutread.h"
  25 #include "timeoutwrite.h"
  26 #include "commands.h"
  27
  28 #define MAXHOPS 100
  29 unsigned int databytes = 0;
  30 int timeout = 1200;
  31
  32 int safewrite(fd,buf,len) int fd; char *buf; int len;
  33 {
  34   int r;
  35   r = timeoutwrite(timeout,fd,buf,len);
  36   if (r <= 0) _exit(1);
  37   return r;
  38 }
  39
  40 char ssoutbuf[512];
  41 substdio ssout = SUBSTDIO_FDBUF(safewrite,1,ssoutbuf,sizeof ssoutbuf);
  42
  43 void flush() { substdio_flush(&ssout); }
  44 void out(s) char *s; { substdio_puts(&ssout,s); }
  45
  46 void die_read() { _exit(1); }
  47 void die_alarm() { out("451 timeout (#4.4.2)\r\n"); flush(); _exit(1); }
  48 void die_nomem() { out("421 out of memory (#4.3.0)\r\n"); flush(); _exit(1); }
  49 void die_control() { out("421 unable to read controls (#4.3.0)\r\n"); flush(); _exit(1); }
  50 void die_ipme() { out("421 unable to figure out my IP addresses (#4.3.0)\r\n"); flush(); _exit(1); }
  51 void die_badaddr() { out("553 too many bad recipients: sulking (#5.5.1)\r\n"); flush(); _exit(1); }
  52 void straynewline() { out("451 See http://pobox.com/~djb/docs/smtplf.html.\r\n"); flush(); _exit(1); }
  53
  54 void err_bmf() { out("553 sorry, your envelope sender is in my badmailfrom list (#5.7.1)\r\n"); }
  55 void err_nogateway() { out("553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)\r\n"); }
  56 void err_badaddr() { out("550 unknown mailbox (#5.1.1)\r\n"); }
  57 void err_unimpl() { out("502 unimplemented (#5.5.1)\r\n"); }
  58 void err_syntax() { out("555 syntax error (#5.5.4)\r\n"); }
  59 void err_wantmail() { out("503 MAIL first (#5.5.1)\r\n"); }
  60 void err_wantrcpt() { out("503 RCPT first (#5.5.1)\r\n"); }
  61 void err_noop() { out("250 ok\r\n"); }
  62 void err_vrfy() { out("252 send some mail, i'll try my best\r\n"); }
  63 void err_qqt() { out("451 qqt failure (#4.3.0)\r\n"); }
  64
  65
  66 stralloc greeting = {0};
  67
  68 void smtp_greet(code) char *code;
  69 {
  70   substdio_puts(&ssout,code);
  71   substdio_put(&ssout,greeting.s,greeting.len);
  72 }
  73 void smtp_help()
  74 {
  75   out("214 qmail home page: http://pobox.com/~djb/qmail.html\r\n");
  76 }
  77 void smtp_quit()
  78 {
  79   smtp_greet("221 "); out("\r\n"); flush(); _exit(0);
  80 }
  81
  82 char *remoteip;
  83 char *remotehost;
  84 char *remoteinfo;
  85 char *local;
  86 char *relayclient;
  87
  88 stralloc helohost = {0};
  89 char *fakehelo; /* pointer into helohost, or 0 */
  90
  91 void dohelo(arg) char *arg; {
  92   if (!stralloc_copys(&helohost,arg)) die_nomem();
  93   if (!stralloc_0(&helohost)) die_nomem();
  94   fakehelo = case_diffs(remotehost,helohost.s) ? helohost.s : 0;
  95 }
  96
  97 int liphostok = 0;
  98 stralloc liphost = {0};
  99 int relayhostsok = 0;
 100 stralloc relayhosts = {0};
 101 struct constmap maprelayhosts;
 102 int bmfok = 0;
 103 stralloc bmf = {0};
 104 struct constmap mapbmf;
 105 static int ac_slow = 5;
 106 static int ac_limit = 50;
 107 static int ac_delay = 2;
 108 static int ac_count = 0;
 109 static int ac_fd = -1;
 110
 111 void setup()
 112 {
 113   char *x;
 114   unsigned long u;
 115
 116   if (control_init() == -1) die_control();
 117   if (control_rldef(&greeting,"control/smtpgreeting",1,(char *) 0) != 1)
 118     die_control();
 119   liphostok = control_rldef(&liphost,"control/localiphost",1,(char *) 0);
 120   if (liphostok == -1) die_control();
 121   if (control_readint(&timeout,"control/timeoutsmtpd") == -1) die_control();
 122   if (timeout <= 0) timeout = 1;
 123
 124   if (rcpthosts_init() == -1) die_control();
 125
 126   bmfok = control_readfile(&bmf,"control/badmailfrom",0);
 127   if (bmfok == -1) die_control();
 128   if (bmfok)
 129     if (!constmap_init(&mapbmf,bmf.s,bmf.len,0)) die_nomem();
 130
 131   switch (control_readfile(&relayhosts, "control/relayhosts", 0)) {
 132     case -1:
 133       die_control();
 134     case 1:
 135       relayhostsok = 1;
 136       if (!constmap_init(&maprelayhosts, relayhosts.s, relayhosts.len, 1))
 137         die_nomem();
 138   }
 139
 140   if (control_readint(&ac_slow, "control/addrcheck-slow") == -1 ||
 141       control_readint(&ac_slow, "control/addrcheck-limit") == -1 ||
 142       control_readint(&ac_slow, "control/addrcheck-delay") == -1)
 143     die_control();
 144
 145   if ((ac_fd = open_read("control/addrcheck.cdb")) < 0 && errno != error_noent)
 146     die_control();
 147
 148   if (control_readint(&databytes,"control/databytes") == -1) die_control();
 149   x = env_get("DATABYTES");
 150   if (x) { scan_ulong(x,&u); databytes = u; }
 151   if (!(databytes + 1)) --databytes;
 152
 153   remoteip = env_get("TCPREMOTEIP");
 154   if (!remoteip) remoteip = "unknown";
 155   local = env_get("TCPLOCALHOST");
 156   if (!local) local = env_get("TCPLOCALIP");
 157   if (!local) local = "unknown";
 158   remotehost = env_get("TCPREMOTEHOST");
 159   if (!remotehost) remotehost = "unknown";
 160   remoteinfo = env_get("TCPREMOTEINFO");
 161   relayclient = env_get("RELAYCLIENT");
 162   if (!relayclient && relayhostsok) {
 163     int j;
 164     int l = str_len(remotehost);
 165     relayclient = constmap(&maprelayhosts, remotehost, l);
 166     if (!relayclient) for (j = 0; j < l; ++j) {
 167       if (remotehost[j] == '.' &&
 168          (relayclient = constmap(&maprelayhosts,
 169                                  remotehost + j,
 170                                  l - j)) != 0)
 171         break;
 172     }
 173   }
 174   dohelo(remotehost);
 175 }
 176
 177
 178 stralloc addr = {0}; /* will be 0-terminated, if addrparse returns 1 */
 179
 180 int addrparse(arg)
 181 char *arg;
 182 {
 183   int i;
 184   char ch;
 185   char terminator;
 186   struct ip_address ip;
 187   int flagesc;
 188   int flagquoted;
 189
 190   terminator = '>';
 191   i = str_chr(arg,'<');
 192   if (arg[i])
 193     arg += i + 1;
 194   else { /* partner should go read rfc 821 */
 195     terminator = ' ';
 196     arg += str_chr(arg,':');
 197     if (*arg == ':') ++arg;
 198     while (*arg == ' ') ++arg;
 199   }
 200
 201   /* strip source route */
 202   if (*arg == '@') while (*arg) if (*arg++ == ':') break;
 203
 204   if (!stralloc_copys(&addr,"")) die_nomem();
 205   flagesc = 0;
 206   flagquoted = 0;
 207   for (i = 0;ch = arg[i];++i) { /* copy arg to addr, stripping quotes */
 208     if (flagesc) {
 209       if (!stralloc_append(&addr,&ch)) die_nomem();
 210       flagesc = 0;
 211     }
 212     else {
 213       if (!flagquoted && (ch == terminator)) break;
 214       switch(ch) {
 215         case '\\': flagesc = 1; break;
 216         case '"': flagquoted = !flagquoted; break;
 217         default: if (!stralloc_append(&addr,&ch)) die_nomem();
 218       }
 219     }
 220   }
 221   /* could check for termination failure here, but why bother? */
 222   if (!stralloc_append(&addr,"")) die_nomem();
 223
 224   if (liphostok) {
 225     i = byte_rchr(addr.s,addr.len,'@');
 226     if (i < addr.len) /* if not, partner should go read rfc 821 */
 227       if (addr.s[i + 1] == '[')
 228         if (!addr.s[i + 1 + ip_scanbracket(addr.s + i + 1,&ip)])
 229           if (ipme_is(&ip)) {
 230             addr.len = i + 1;
 231             if (!stralloc_cat(&addr,&liphost)) die_nomem();
 232             if (!stralloc_0(&addr)) die_nomem();
 233           }
 234   }
 235
 236   if (addr.len > 900) return 0;
 237   return 1;
 238 }
 239
 240 int bmfcheck()
 241 {
 242   int j;
 243   if (!bmfok) return 0;
 244   if (constmap(&mapbmf,addr.s,addr.len - 1)) return 1;
 245   j = byte_rchr(addr.s,addr.len,'@');
 246   if (j < addr.len)
 247     if (constmap(&mapbmf,addr.s + j,addr.len - j - 1)) return 1;
 248   return 0;
 249 }
 250
 251 int addrallowed()
 252 {
 253   int r;
 254   r = rcpthosts(addr.s,str_len(addr.s));
 255   if (r == -1) die_control();
 256   return r;
 257 }
 258
 259
 260 int seenmail = 0;
 261 int flagbarf; /* defined if seenmail */
 262 stralloc mailfrom = {0};
 263 stralloc rcptto = {0};
 264
 265 void smtp_helo(arg) char *arg;
 266 {
 267   smtp_greet("250 "); out("\r\n");
 268   seenmail = 0; dohelo(arg);
 269 }
 270 void smtp_ehlo(arg) char *arg;
 271 {
 272   smtp_greet("250-"); out("\r\n250-PIPELINING\r\n250 8BITMIME\r\n");
 273   seenmail = 0; dohelo(arg);
 274 }
 275 void smtp_rset()
 276 {
 277   seenmail = 0;
 278   out("250 flushed\r\n");
 279 }
 280 void smtp_mail(arg) char *arg;
 281 {
 282   if (!addrparse(arg)) { err_syntax(); return; }
 283   flagbarf = bmfcheck();
 284   seenmail = 1;
 285   if (!stralloc_copys(&rcptto,"")) die_nomem();
 286   if (!stralloc_copys(&mailfrom,addr.s)) die_nomem();
 287   if (!stralloc_0(&mailfrom)) die_nomem();
 288   out("250 ok\r\n");
 289 }
 290 void smtp_rcpt(arg) char *arg; {
 291   if (!seenmail) { err_wantmail(); return; }
 292   if (!addrparse(arg)) { err_syntax(); return; }
 293   if (flagbarf) { err_bmf(); return; }
 294   if (relayclient) {
 295     --addr.len;
 296     if (!stralloc_cats(&addr,relayclient)) die_nomem();
 297     if (!stralloc_0(&addr)) die_nomem();
 298   }
 299   else
 300     if (!addrallowed()) { err_nogateway(); return; }
 301   if (ac_fd != -1) {
 302     int rc;
 303     if (addrcheck(ac_fd, addr.s, mailfrom.s, &rc) < 0) {
 304       if (errno == error_nomem)
 305         die_nomem();
 306       else
 307         die_control();
 308     }
 309     if (!rc) {
 310       ac_count++;
 311       if (ac_limit && ac_count >= ac_limit) die_badaddr();
 312       if (ac_delay && ac_count >= ac_slow) sleep(ac_delay);
 313       err_badaddr();
 314       return;
 315     }
 316   }
 317   if (!stralloc_cats(&rcptto,"T")) die_nomem();
 318   if (!stralloc_cats(&rcptto,addr.s)) die_nomem();
 319   if (!stralloc_0(&rcptto)) die_nomem();
 320   out("250 ok\r\n");
 321 }
 322
 323
 324 int saferead(fd,buf,len) int fd; char *buf; int len;
 325 {
 326   int r;
 327   flush();
 328   r = timeoutread(timeout,fd,buf,len);
 329   if (r == -1) if (errno == error_timeout) die_alarm();
 330   if (r <= 0) die_read();
 331   return r;
 332 }
 333
 334 char ssinbuf[1024];
 335 substdio ssin = SUBSTDIO_FDBUF(saferead,0,ssinbuf,sizeof ssinbuf);
 336
 337 struct qmail qqt;
 338 unsigned int bytestooverflow = 0;
 339
 340 void put(ch)
 341 char *ch;
 342 {
 343   if (bytestooverflow)
 344     if (!--bytestooverflow)
 345       qmail_fail(&qqt);
 346   qmail_put(&qqt,ch,1);
 347 }
 348
 349 void blast(hops)
 350 int *hops;
 351 {
 352   char ch;
 353   int state;
 354   int flaginheader;
 355   int pos; /* number of bytes since most recent \n, if fih */
 356   int flagmaybex; /* 1 if this line might match RECEIVED, if fih */
 357   int flagmaybey; /* 1 if this line might match \r\n, if fih */
 358   int flagmaybez; /* 1 if this line might match DELIVERED, if fih */
 359
 360   state = 1;
 361   *hops = 0;
 362   flaginheader = 1;
 363   pos = 0; flagmaybex = flagmaybey = flagmaybez = 1;
 364   for (;;) {
 365     substdio_get(&ssin,&ch,1);
 366     if (flaginheader) {
 367       if (pos < 9) {
 368         if (ch != "delivered"[pos]) if (ch != "DELIVERED"[pos]) flagmaybez = 0;
 369         if (flagmaybez) if (pos == 8) ++*hops;
 370         if (pos < 8)
 371           if (ch != "received"[pos]) if (ch != "RECEIVED"[pos]) flagmaybex = 0;
 372         if (flagmaybex) if (pos == 7) ++*hops;
 373         if (pos < 2) if (ch != "\r\n"[pos]) flagmaybey = 0;
 374         if (flagmaybey) if (pos == 1) flaginheader = 0;
 375       }
 376       ++pos;
 377       if (ch == '\n') { pos = 0; flagmaybex = flagmaybey = flagmaybez = 1; }
 378     }
 379     switch(state) {
 380       case 0:
 381         if (ch == '\n') straynewline();
 382         if (ch == '\r') { state = 4; continue; }
 383         break;
 384       case 1: /* \r\n */
 385         if (ch == '\n') straynewline();
 386         if (ch == '.') { state = 2; continue; }
 387         if (ch == '\r') { state = 4; continue; }
 388         state = 0;
 389         break;
 390       case 2: /* \r\n + . */
 391         if (ch == '\n') straynewline();
 392         if (ch == '\r') { state = 3; continue; }
 393         state = 0;
 394         break;
 395       case 3: /* \r\n + .\r */
 396         if (ch == '\n') return;
 397         put(".");
 398         put("\r");
 399         if (ch == '\r') { state = 4; continue; }
 400         state = 0;
 401         break;
 402       case 4: /* + \r */
 403         if (ch == '\n') { state = 1; break; }
 404         if (ch != '\r') { put("\r"); state = 0; }
 405     }
 406     put(&ch);
 407   }
 408 }
 409
 410 char accept_buf[FMT_ULONG];
 411 void acceptmessage(qp) unsigned long qp;
 412 {
 413   datetime_sec when;
 414   when = now();
 415   out("250 ok ");
 416   accept_buf[fmt_ulong(accept_buf,(unsigned long) when)] = 0;
 417   out(accept_buf);
 418   out(" qp ");
 419   accept_buf[fmt_ulong(accept_buf,qp)] = 0;
 420   out(accept_buf);
 421   out("\r\n");
 422 }
 423
 424 void smtp_data() {
 425   int hops;
 426   unsigned long qp;
 427   char *qqx;
 428
 429   if (!seenmail) { err_wantmail(); return; }
 430   if (!rcptto.len) { err_wantrcpt(); return; }
 431   seenmail = 0;
 432   if (databytes) bytestooverflow = databytes + 1;
 433   if (qmail_open(&qqt) == -1) { err_qqt(); return; }
 434   qp = qmail_qp(&qqt);
 435   out("354 go ahead\r\n");
 436
 437   received(&qqt,"SMTP",local,remoteip,remotehost,remoteinfo,fakehelo);
 438   blast(&hops);
 439   hops = (hops >= MAXHOPS);
 440   if (hops) qmail_fail(&qqt);
 441   qmail_from(&qqt,mailfrom.s);
 442   qmail_put(&qqt,rcptto.s,rcptto.len);
 443
 444   qqx = qmail_close(&qqt);
 445   if (!*qqx) { acceptmessage(qp); return; }
 446   if (hops) { out("554 too many hops, this message is looping (#5.4.6)\r\n"); return; }
 447   if (databytes) if (!bytestooverflow) { out("552 sorry, that message size exceeds my databytes limit (#5.3.4)\r\n"); return; }
 448   if (*qqx == 'D') out("554 "); else out("451 ");
 449   out(qqx + 1);
 450   out("\r\n");
 451 }
 452
 453 struct commands smtpcommands[] = {
 454   { "rcpt", smtp_rcpt, 0 }
 455 , { "mail", smtp_mail, 0 }
 456 , { "data", smtp_data, flush }
 457 , { "quit", smtp_quit, flush }
 458 , { "helo", smtp_helo, flush }
 459 , { "ehlo", smtp_ehlo, flush }
 460 , { "rset", smtp_rset, 0 }
 461 , { "help", smtp_help, flush }
 462 , { "noop", err_noop, flush }
 463 , { "vrfy", err_vrfy, flush }
 464 , { 0, err_unimpl, flush }
 465 } ;
 466
 467 void main()
 468 {
 469   sig_pipeignore();
 470   if (chdir(auto_qmail) == -1) die_control();
 471   setup();
 472   if (ipme_init() != 1) die_ipme();
 473   smtp_greet("220 ");
 474   out(" ESMTP\r\n");
 475   if (commands(&ssin,&smtpcommands) == 0) die_read();
 476   die_nomem();
 477 }