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 bmfok = 0;
  97 stralloc bmf = {0};
  98 struct constmap mapbmf;
  99
 100 void setup()
 101 {
 102   char *x;
 103   unsigned long u;
 104
 105   if (control_init() == -1) die_control();
 106   if (control_rldef(&greeting,"control/smtpgreeting",1,(char *) 0) != 1)
 107     die_control();
 108   liphostok = control_rldef(&liphost,"control/localiphost",1,(char *) 0);
 109   if (liphostok == -1) die_control();
 110   if (control_readint(&timeout,"control/timeoutsmtpd") == -1) die_control();
 111   if (timeout <= 0) timeout = 1;
 112
 113   if (rcpthosts_init() == -1) die_control();
 114
 115   bmfok = control_readfile(&bmf,"control/badmailfrom",0);
 116   if (bmfok == -1) die_control();
 117   if (bmfok)
 118     if (!constmap_init(&mapbmf,bmf.s,bmf.len,0)) die_nomem();
 119
 120   if (control_readint(&databytes,"control/databytes") == -1) die_control();
 121   x = env_get("DATABYTES");
 122   if (x) { scan_ulong(x,&u); databytes = u; }
 123   if (!(databytes + 1)) --databytes;
 124
 125   remoteip = env_get("TCPREMOTEIP");
 126   if (!remoteip) remoteip = "unknown";
 127   local = env_get("TCPLOCALHOST");
 128   if (!local) local = env_get("TCPLOCALIP");
 129   if (!local) local = "unknown";
 130   remotehost = env_get("TCPREMOTEHOST");
 131   if (!remotehost) remotehost = "unknown";
 132   remoteinfo = env_get("TCPREMOTEINFO");
 133   relayclient = env_get("RELAYCLIENT");
 134   dohelo(remotehost);
 135 }
 136
 137
 138 stralloc addr = {0}; /* will be 0-terminated, if addrparse returns 1 */
 139
 140 int addrparse(arg)
 141 char *arg;
 142 {
 143   int i;
 144   char ch;
 145   char terminator;
 146   struct ip_address ip;
 147   int flagesc;
 148   int flagquoted;
 149
 150   terminator = '>';
 151   i = str_chr(arg,'<');
 152   if (arg[i])
 153     arg += i + 1;
 154   else { /* partner should go read rfc 821 */
 155     terminator = ' ';
 156     arg += str_chr(arg,':');
 157     if (*arg == ':') ++arg;
 158     while (*arg == ' ') ++arg;
 159   }
 160
 161   /* strip source route */
 162   if (*arg == '@') while (*arg) if (*arg++ == ':') break;
 163
 164   if (!stralloc_copys(&addr,"")) die_nomem();
 165   flagesc = 0;
 166   flagquoted = 0;
 167   for (i = 0;ch = arg[i];++i) { /* copy arg to addr, stripping quotes */
 168     if (flagesc) {
 169       if (!stralloc_append(&addr,&ch)) die_nomem();
 170       flagesc = 0;
 171     }
 172     else {
 173       if (!flagquoted && (ch == terminator)) break;
 174       switch(ch) {
 175         case '\\': flagesc = 1; break;
 176         case '"': flagquoted = !flagquoted; break;
 177         default: if (!stralloc_append(&addr,&ch)) die_nomem();
 178       }
 179     }
 180   }
 181   /* could check for termination failure here, but why bother? */
 182   if (!stralloc_append(&addr,"")) die_nomem();
 183
 184   if (liphostok) {
 185     i = byte_rchr(addr.s,addr.len,'@');
 186     if (i < addr.len) /* if not, partner should go read rfc 821 */
 187       if (addr.s[i + 1] == '[')
 188         if (!addr.s[i + 1 + ip_scanbracket(addr.s + i + 1,&ip)])
 189           if (ipme_is(&ip)) {
 190             addr.len = i + 1;
 191             if (!stralloc_cat(&addr,&liphost)) die_nomem();
 192             if (!stralloc_0(&addr)) die_nomem();
 193           }
 194   }
 195
 196   if (addr.len > 900) return 0;
 197   return 1;
 198 }
 199
 200 int bmfcheck()
 201 {
 202   int j;
 203   if (!bmfok) return 0;
 204   if (constmap(&mapbmf,addr.s,addr.len - 1)) return 1;
 205   j = byte_rchr(addr.s,addr.len,'@');
 206   if (j < addr.len)
 207     if (constmap(&mapbmf,addr.s + j,addr.len - j - 1)) return 1;
 208   return 0;
 209 }
 210
 211 int addrallowed()
 212 {
 213   int r;
 214   r = rcpthosts(addr.s,str_len(addr.s));
 215   if (r == -1) die_control();
 216   return r;
 217 }
 218
 219
 220 int seenmail = 0;
 221 int flagbarf; /* defined if seenmail */
 222 stralloc mailfrom = {0};
 223 stralloc rcptto = {0};
 224
 225 void smtp_helo(arg) char *arg;
 226 {
 227   smtp_greet("250 "); out("\r\n");
 228   seenmail = 0; dohelo(arg);
 229 }
 230 void smtp_ehlo(arg) char *arg;
 231 {
 232   smtp_greet("250-"); out("\r\n250-PIPELINING\r\n250 8BITMIME\r\n");
 233   seenmail = 0; dohelo(arg);
 234 }
 235 void smtp_rset()
 236 {
 237   seenmail = 0;
 238   out("250 flushed\r\n");
 239 }
 240 void smtp_mail(arg) char *arg;
 241 {
 242   if (!addrparse(arg)) { err_syntax(); return; }
 243   flagbarf = bmfcheck();
 244   seenmail = 1;
 245   if (!stralloc_copys(&rcptto,"")) die_nomem();
 246   if (!stralloc_copys(&mailfrom,addr.s)) die_nomem();
 247   if (!stralloc_0(&mailfrom)) die_nomem();
 248   out("250 ok\r\n");
 249 }
 250 void smtp_rcpt(arg) char *arg; {
 251   if (!seenmail) { err_wantmail(); return; }
 252   if (!addrparse(arg)) { err_syntax(); return; }
 253   if (flagbarf) { err_bmf(); return; }
 254   if (relayclient) {
 255     --addr.len;
 256     if (!stralloc_cats(&addr,relayclient)) die_nomem();
 257     if (!stralloc_0(&addr)) die_nomem();
 258   }
 259   else
 260     if (!addrallowed()) { err_nogateway(); return; }
 261   if (!stralloc_cats(&rcptto,"T")) die_nomem();
 262   if (!stralloc_cats(&rcptto,addr.s)) die_nomem();
 263   if (!stralloc_0(&rcptto)) die_nomem();
 264   out("250 ok\r\n");
 265 }
 266
 267
 268 int saferead(fd,buf,len) int fd; char *buf; int len;
 269 {
 270   int r;
 271   flush();
 272   r = timeoutread(timeout,fd,buf,len);
 273   if (r == -1) if (errno == error_timeout) die_alarm();
 274   if (r <= 0) die_read();
 275   return r;
 276 }
 277
 278 char ssinbuf[1024];
 279 substdio ssin = SUBSTDIO_FDBUF(saferead,0,ssinbuf,sizeof ssinbuf);
 280
 281 struct qmail qqt;
 282 unsigned int bytestooverflow = 0;
 283
 284 void put(ch)
 285 char *ch;
 286 {
 287   if (bytestooverflow)
 288     if (!--bytestooverflow)
 289       qmail_fail(&qqt);
 290   qmail_put(&qqt,ch,1);
 291 }
 292
 293 void blast(hops)
 294 int *hops;
 295 {
 296   char ch;
 297   int state;
 298   int flaginheader;
 299   int pos; /* number of bytes since most recent \n, if fih */
 300   int flagmaybex; /* 1 if this line might match RECEIVED, if fih */
 301   int flagmaybey; /* 1 if this line might match \r\n, if fih */
 302   int flagmaybez; /* 1 if this line might match DELIVERED, if fih */
 303
 304   state = 1;
 305   *hops = 0;
 306   flaginheader = 1;
 307   pos = 0; flagmaybex = flagmaybey = flagmaybez = 1;
 308   for (;;) {
 309     substdio_get(&ssin,&ch,1);
 310     if (flaginheader) {
 311       if (pos < 9) {
 312         if (ch != "delivered"[pos]) if (ch != "DELIVERED"[pos]) flagmaybez = 0;
 313         if (flagmaybez) if (pos == 8) ++*hops;
 314         if (pos < 8)
 315           if (ch != "received"[pos]) if (ch != "RECEIVED"[pos]) flagmaybex = 0;
 316         if (flagmaybex) if (pos == 7) ++*hops;
 317         if (pos < 2) if (ch != "\r\n"[pos]) flagmaybey = 0;
 318         if (flagmaybey) if (pos == 1) flaginheader = 0;
 319       }
 320       ++pos;
 321       if (ch == '\n') { pos = 0; flagmaybex = flagmaybey = flagmaybez = 1; }
 322     }
 323     switch(state) {
 324       case 0:
 325         if (ch == '\n') straynewline();
 326         if (ch == '\r') { state = 4; continue; }
 327         break;
 328       case 1: /* \r\n */
 329         if (ch == '\n') straynewline();
 330         if (ch == '.') { state = 2; continue; }
 331         if (ch == '\r') { state = 4; continue; }
 332         state = 0;
 333         break;
 334       case 2: /* \r\n + . */
 335         if (ch == '\n') straynewline();
 336         if (ch == '\r') { state = 3; continue; }
 337         state = 0;
 338         break;
 339       case 3: /* \r\n + .\r */
 340         if (ch == '\n') return;
 341         put(".");
 342         put("\r");
 343         if (ch == '\r') { state = 4; continue; }
 344         state = 0;
 345         break;
 346       case 4: /* + \r */
 347         if (ch == '\n') { state = 1; break; }
 348         if (ch != '\r') { put("\r"); state = 0; }
 349     }
 350     put(&ch);
 351   }
 352 }
 353
 354 char accept_buf[FMT_ULONG];
 355 void acceptmessage(qp) unsigned long qp;
 356 {
 357   datetime_sec when;
 358   when = now();
 359   out("250 ok ");
 360   accept_buf[fmt_ulong(accept_buf,(unsigned long) when)] = 0;
 361   out(accept_buf);
 362   out(" qp ");
 363   accept_buf[fmt_ulong(accept_buf,qp)] = 0;
 364   out(accept_buf);
 365   out("\r\n");
 366 }
 367
 368 void smtp_data() {
 369   int hops;
 370   unsigned long qp;
 371   char *qqx;
 372
 373   if (!seenmail) { err_wantmail(); return; }
 374   if (!rcptto.len) { err_wantrcpt(); return; }
 375   seenmail = 0;
 376   if (databytes) bytestooverflow = databytes + 1;
 377   if (qmail_open(&qqt) == -1) { err_qqt(); return; }
 378   qp = qmail_qp(&qqt);
 379   out("354 go ahead\r\n");
 380
 381   received(&qqt,"SMTP",local,remoteip,remotehost,remoteinfo,fakehelo);
 382   blast(&hops);
 383   hops = (hops >= MAXHOPS);
 384   if (hops) qmail_fail(&qqt);
 385   qmail_from(&qqt,mailfrom.s);
 386   qmail_put(&qqt,rcptto.s,rcptto.len);
 387
 388   qqx = qmail_close(&qqt);
 389   if (!*qqx) { acceptmessage(qp); return; }
 390   if (hops) { out("554 too many hops, this message is looping (#5.4.6)\r\n"); return; }
 391   if (databytes) if (!bytestooverflow) { out("552 sorry, that message size exceeds my databytes limit (#5.3.4)\r\n"); return; }
 392   if (*qqx == 'D') out("554 "); else out("451 ");
 393   out(qqx + 1);
 394   out("\r\n");
 395 }
 396
 397 struct commands smtpcommands[] = {
 398   { "rcpt", smtp_rcpt, 0 }
 399 , { "mail", smtp_mail, 0 }
 400 , { "data", smtp_data, flush }
 401 , { "quit", smtp_quit, flush }
 402 , { "helo", smtp_helo, flush }
 403 , { "ehlo", smtp_ehlo, flush }
 404 , { "rset", smtp_rset, 0 }
 405 , { "help", smtp_help, flush }
 406 , { "noop", err_noop, flush }
 407 , { "vrfy", err_vrfy, flush }
 408 , { 0, err_unimpl, flush }
 409 } ;
 410
 411 void main()
 412 {
 413   sig_pipeignore();
 414   if (chdir(auto_qmail) == -1) die_control();
 415   setup();
 416   if (ipme_init() != 1) die_ipme();
 417   smtp_greet("220 ");
 418   out(" ESMTP\r\n");
 419   if (commands(&ssin,&smtpcommands) == 0) die_read();
 420   die_nomem();
 421 }