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