/* * sink.c -- forwarding/delivery support for fetchmail * * The interface of this module (open_sink(), stuff_line(), close_sink(), * release_sink()) seals off the delivery logic from the protocol machine, * so the latter won't have to care whether it's shipping to an [SL]MTP * listener daemon or an MDA pipe. * * Copyright 1998 by Eric S. Raymond * For license terms, see the file COPYING in this directory. */ #include "config.h" #include #include #include #include #include #ifdef HAVE_MEMORY_H #include #endif /* HAVE_MEMORY_H */ #if defined(STDC_HEADERS) #include #endif #if defined(HAVE_UNISTD_H) #include #endif #if defined(HAVE_STDARG_H) #include #else #include #endif #include #include #include "fetchmail.h" #include "socket.h" #include "smtp.h" #include "i18n.h" /* BSD portability hack...I know, this is an ugly place to put it */ #if !defined(SIGCHLD) && defined(SIGCLD) #define SIGCHLD SIGCLD #endif /* makes the open_sink()/close_sink() pair non-reentrant */ static int lmtp_responses; int smtp_open(struct query *ctl) /* try to open a socket to the appropriate SMTP server for this query */ { char *parsed_host = NULL; /* maybe it's time to close the socket in order to force delivery */ if (NUM_NONZERO(ctl->batchlimit) && (ctl->smtp_socket != -1) && ++batchcount == ctl->batchlimit) { SockClose(ctl->smtp_socket); ctl->smtp_socket = -1; batchcount = 0; } /* if no socket to any SMTP host is already set up, try to open one */ if (ctl->smtp_socket == -1) { /* * RFC 1123 requires that the domain name in HELO address is a * "valid principal domain name" for the client host. If we're * running in invisible mode, violate this with malice * aforethought in order to make the Received headers and * logging look right. * * In fact this code relies on the RFC1123 requirement that the * SMTP listener must accept messages even if verification of the * HELO name fails (RFC1123 section 5.2.5, paragraph 2). * * How we compute the true mailhost name to pass to the * listener doesn't affect behavior on RFC1123-violating * listeners that check for name match; we're going to lose * on those anyway because we can never give them a name * that matches the local machine fetchmail is running on. * What it will affect is the listener's logging. */ struct idlist *idp; const char *id_me = run.invisible ? ctl->server.truename : fetchmailhost; int oldphase = phase; errno = 0; /* * Run down the SMTP hunt list looking for a server that's up. * Use both explicit hunt entries (value TRUE) and implicit * (default) ones (value FALSE). */ oldphase = phase; phase = LISTENER_WAIT; set_timeout(ctl->server.timeout); for (idp = ctl->smtphunt; idp; idp = idp->next) { char *cp; #ifdef INET6_ENABLE char *portnum = SMTP_PORT; #else int portnum = SMTP_PORT; #endif /* INET6_ENABLE */ xalloca(parsed_host, char *, strlen(idp->id) + 1); ctl->smtphost = idp->id; /* remember last host tried. */ if(ctl->smtphost[0]=='/') ctl->listener = LMTP_MODE; strcpy(parsed_host, idp->id); if ((cp = strrchr(parsed_host, '/'))) { *cp++ = 0; #ifdef INET6_ENABLE portnum = cp; #else portnum = atoi(cp); #endif /* INET6_ENABLE */ } if (ctl->smtphost[0]=='/'){ if((ctl->smtp_socket = UnixOpen(ctl->smtphost))==-1) continue; } else if ((ctl->smtp_socket = SockOpen(parsed_host,portnum,NULL, ctl->server.plugout)) == -1) continue; /* return immediately for ODMR */ if (ctl->server.protocol == P_ODMR) return(ctl->smtp_socket); /* success */ /* are we doing SMTP or LMTP? */ SMTP_setmode(ctl->listener); /* first, probe for ESMTP */ if (SMTP_ok(ctl->smtp_socket) == SM_OK && SMTP_ehlo(ctl->smtp_socket, id_me, &ctl->server.esmtp_options) == SM_OK) break; /* success */ /* * RFC 1869 warns that some listeners hang up on a failed EHLO, * so it's safest not to assume the socket will still be good. */ SockClose(ctl->smtp_socket); ctl->smtp_socket = -1; /* if opening for ESMTP failed, try SMTP */ if ((ctl->smtp_socket = SockOpen(parsed_host,portnum,NULL, ctl->server.plugout)) == -1) continue; if (SMTP_ok(ctl->smtp_socket) == SM_OK && SMTP_helo(ctl->smtp_socket, id_me) == SM_OK) break; /* success */ SockClose(ctl->smtp_socket); ctl->smtp_socket = -1; } set_timeout(0); phase = oldphase; } /* * RFC 1123 requires that the domain name part of the * RCPT TO address be "canonicalized", that is a FQDN * or MX but not a CNAME. Some listeners (like exim) * enforce this. Now that we have the actual hostname, * compute what we should canonicalize with. * * make sure we do not forget to drop the /port if * using LMTP (hmh) */ if (ctl->listener == LMTP_MODE && !ctl->smtpaddress) { if (parsed_host && parsed_host[0] != 0) ctl->destaddr = xstrdup(parsed_host); else ctl->destaddr = (ctl->smtphost && ctl->smtphost[0] != '/') ? ctl->smtphost : "localhost"; } else ctl->destaddr = ctl->smtpaddress ? ctl->smtpaddress : ( ctl->smtphost && ctl->smtphost[0] != '/' ? ctl->smtphost : "localhost"); if (outlevel >= O_DEBUG && ctl->smtp_socket != -1) report(stdout, GT_("forwarding to %s\n"), ctl->smtphost); return(ctl->smtp_socket); } static void sanitize(char *s) /* replace unsafe shellchars by an _ */ { const static char *ok_chars = " 1234567890!@%-_=+:,./abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; char *cp; for (cp = s; *(cp += strspn(cp, ok_chars)); /* NO INCREMENT */) *cp = '_'; } static int send_bouncemail(struct query *ctl, struct msgblk *msg, int userclass, char *message, int nerrors, char *errors[]) /* bounce back an error report a la RFC 1892 */ { char daemon_name[18 + HOSTLEN] = "FETCHMAIL-DAEMON@"; char boundary[BUFSIZ], *bounce_to; int sock; /* don't bounce in reply to undeliverable bounces */ if (!msg->return_path[0] || strcmp(msg->return_path, "<>") == 0) return(FALSE); bounce_to = (run.bouncemail ? msg->return_path : run.postmaster); SMTP_setmode(SMTP_MODE); /* can't just use fetchmailhost here, it might be localhost */ strcat(daemon_name, host_fqdn()); /* we need only SMTP for this purpose */ if ((sock = SockOpen("localhost", SMTP_PORT, NULL, NULL)) == -1 || SMTP_ok(sock) != SM_OK || SMTP_helo(sock, fetchmailhost) != SM_OK || SMTP_from(sock, daemon_name, (char *)NULL) != SM_OK || SMTP_rcpt(sock, bounce_to) != SM_OK || SMTP_data(sock) != SM_OK) return(FALSE); /* our first duty is to keep the sacred foo counters turning... */ #ifdef HAVE_SNPRINTF snprintf(boundary, sizeof(boundary), #else sprintf(boundary, #endif /* HAVE_SNPRINTF */ "foo-mani-padme-hum-%d-%d-%ld", (int)getpid(), (int)getppid(), time((time_t *)NULL)); if (outlevel >= O_VERBOSE) report(stdout, GT_("SMTP: (bounce-message body)\n")); else /* this will usually go to sylog... */ report(stderr, GT_("mail from %s bounced to %s\n"), daemon_name, bounce_to); /* bouncemail headers */ SockPrintf(sock, "Return-Path: <>\r\n"); SockPrintf(sock, "From: %s\r\n", daemon_name); SockPrintf(sock, "To: %s\r\n", bounce_to); SockPrintf(sock, "MIME-Version: 1.0\r\n"); SockPrintf(sock, "Content-Type: multipart/report; report-type=delivery-status;\r\n\tboundary=\"%s\"\r\n", boundary); SockPrintf(sock, "\r\n"); /* RFC1892 part 1 -- human-readable message */ SockPrintf(sock, "--%s\r\n", boundary); SockPrintf(sock,"Content-Type: text/plain\r\n"); SockPrintf(sock, "\r\n"); SockWrite(sock, message, strlen(message)); SockPrintf(sock, "\r\n"); SockPrintf(sock, "\r\n"); if (nerrors) { struct idlist *idp; int nusers; /* RFC1892 part 2 -- machine-readable responses */ SockPrintf(sock, "--%s\r\n", boundary); SockPrintf(sock,"Content-Type: message/delivery-status\r\n"); SockPrintf(sock, "\r\n"); SockPrintf(sock, "Reporting-MTA: dns; %s\r\n", fetchmailhost); nusers = 0; for (idp = msg->recipients; idp; idp = idp->next) if (idp->val.status.mark == userclass) { char *error; /* Minimum RFC1894 compliance + Diagnostic-Code field */ SockPrintf(sock, "\r\n"); SockPrintf(sock, "Final-Recipient: rfc822; %s@%s\r\n", idp->id, fetchmailhost); SockPrintf(sock, "Last-Attempt-Date: %s\r\n", rfc822timestamp()); SockPrintf(sock, "Action: failed\r\n"); if (nerrors == 1) /* one error applies to all users */ error = errors[0]; else if (nerrors > nusers) { SockPrintf(sock, "Internal error: SMTP error count doesn't match number of recipients.\r\n"); break; } else /* errors correspond 1-1 to selected users */ error = errors[nusers++]; if (strlen(error) > 9 && isdigit(error[4]) && error[5] == '.' && isdigit(error[6]) && error[7] == '.' && isdigit(error[8])) /* Enhanced status code available, use it */ SockPrintf(sock, "Status: %5.5s\r\n", &(error[4])); else /* Enhanced status code not available, fake one */ SockPrintf(sock, "Status: %c.0.0\r\n", error[0]); SockPrintf(sock, "Diagnostic-Code: %s\r\n", error); } SockPrintf(sock, "\r\n"); } /* RFC1892 part 3 -- headers of undelivered message */ SockPrintf(sock, "--%s\r\n", boundary); SockPrintf(sock, "Content-Type: text/rfc822-headers\r\n"); SockPrintf(sock, "\r\n"); SockWrite(sock, msg->headers, strlen(msg->headers)); SockPrintf(sock, "\r\n"); SockPrintf(sock, "--%s--\r\n", boundary); if (SMTP_eom(sock) != SM_OK || SMTP_quit(sock)) return(FALSE); SockClose(sock); return(TRUE); } static int handle_smtp_report(struct query *ctl, struct msgblk *msg) /* handle SMTP errors based on the content of SMTP_response */ /* return of PS_REFUSED deletes mail from the server; PS_TRANSIENT keeps it */ { int smtperr = atoi(smtp_response); char *responses[1]; xalloca(responses[0], char *, strlen(smtp_response)+1); strcpy(responses[0], smtp_response); #ifdef __UNUSED__ /* * Don't do this! It can really mess you up if, for example, you're * reporting an error with a single RCPT TO address among several; * RSET discards the message body and it doesn't get sent to the * valid recipients. */ SMTP_rset(ctl->smtp_socket); /* stay on the safe side */ if (outlevel >= O_DEBUG) report(stdout, GT_("Saved error is still %d\n"), smtperr); #endif /* __UNUSED */ /* * Note: send_bouncemail message strings are not made subject * to gettext translation because (a) they're going to be * embedded in a text/plain 7bit part, and (b) they're * going to be associated with listener error-response * messages, which are probably in English (none of the * MTAs I know about are internationalized). */ if (str_find(&ctl->antispam, smtperr)) { /* * SMTP listener explicitly refuses to deliver mail * coming from this address, probably due to an * anti-spam domain exclusion. Respect this. Don't * try to ship the message, and don't prevent it from * being deleted. There's no point in bouncing the * email either since most spammers don't put their * real return email address anywhere in the headers * (unless the user insists with the SET SPAMBOUNCE * config option). * * Default values: * * 571 = sendmail's "unsolicited email refused" * 550 = exim's new antispam response (temporary) * 501 = exim's old antispam response * 554 = Postfix antispam response. * */ if (run.spambounce) send_bouncemail(ctl, msg, XMIT_ACCEPT, "Our spam filter rejected this transaction.\r\n", 1, responses); return(PS_REFUSED); } /* * Suppress error message only if the response specifically * meant `excluded for policy reasons'. We *should* see * an error when the return code is less specific. */ if (smtperr >= 400) report(stderr, GT_("%cMTP error: %s\n"), ctl->listener, responses[0]); switch (smtperr) { case 552: /* message exceeds fixed maximum message size */ /* * Permanent no-go condition on the * ESMTP server. Don't try to ship the message, * and allow it to be deleted. */ send_bouncemail(ctl, msg, XMIT_ACCEPT, "This message was too large (SMTP error 552).\r\n", 1, responses); return(run.bouncemail ? PS_REFUSED : PS_TRANSIENT); case 553: /* invalid sending domain */ /* * These latter days 553 usually means a spammer is trying to * cover his tracks. We never bouncemail on these, because * (a) the return address is invalid by definition, and * (b) we wouldn't want spammers to get confirmation that * this address is live, anyway. */ send_bouncemail(ctl, msg, XMIT_ACCEPT, "Invalid address in MAIL FROM (SMTP error 553).\r\n", 1, responses); return(PS_REFUSED); default: /* bounce non-transient errors back to the sender */ if (smtperr >= 500 && smtperr <= 599) if (send_bouncemail(ctl, msg, XMIT_ACCEPT, "General SMTP/ESMTP error.\r\n", 1, responses)) return(run.bouncemail ? PS_REFUSED : PS_TRANSIENT); /* * We're going to end up here on 4xx errors, like: * * 451: temporarily unable to identify sender (exim) * 452: temporary out-of-queue-space condition on the ESMTP server. * * These are temporary errors. Don't try to ship the message, * and suppress deletion so it can be retried on a future * retrieval cycle. * * Bouncemail *might* be appropriate here as a delay * notification (note; if we ever add this, we must make * sure the RFC1894 Action field is "delayed" rather thwn * "failed"). But it's not really necessary because * these are not actual failures, we're very likely to be * able to recover on the next cycle. */ return(PS_TRANSIENT); } } /* these are shared by open_sink and stuffline */ #ifndef HAVE_SIGACTION static RETSIGTYPE (*sigchld)(int); #else static struct sigaction sa_old; #endif /* HAVE_SIGACTION */ static FILE *sinkfp; int stuffline(struct query *ctl, char *buf) /* ship a line to the given control block's output sink (SMTP server or MDA) */ { int n, oldphase; char *last; /* The line may contain NUL characters. Find the last char to use * -- the real line termination is the sequence "\n\0". */ last = buf; while ((last += strlen(last)) && (last[-1] != '\n')) last++; /* fix message lines that have only \n termination (for qmail) */ if (ctl->forcecr) { if (last - 1 == buf || last[-2] != '\r') { last[-1] = '\r'; *last++ = '\n'; *last = '\0'; } } oldphase = phase; phase = FORWARDING_WAIT; /* * SMTP byte-stuffing. We only do this if the protocol does *not* * use . as EOM. If it does, the server will already have * decorated any . lines it sends back up. */ if (*buf == '.') { if (ctl->server.base_protocol->delimited) /* server has already byte-stuffed */ { if (ctl->mda) ++buf; else /* writing to SMTP, leave the byte-stuffing in place */; } else /* if (!protocol->delimited) -- not byte-stuffed already */ { if (!ctl->mda) SockWrite(ctl->smtp_socket, buf, 1); /* byte-stuff it */ else /* leave it alone */; } } /* we may need to strip carriage returns */ if (ctl->stripcr) { char *sp, *tp; for (sp = tp = buf; sp < last; sp++) if (*sp != '\r') *tp++ = *sp; *tp = '\0'; last = tp; } n = 0; if (ctl->mda || ctl->bsmtp) n = fwrite(buf, 1, last - buf, sinkfp); else if (ctl->smtp_socket != -1) n = SockWrite(ctl->smtp_socket, buf, last - buf); phase = oldphase; return(n); } static int open_bsmtp_sink(struct query *ctl, struct msgblk *msg, int *good_addresses, int *bad_addresses) /* open a BSMTP stream */ { struct idlist *idp; if (strcmp(ctl->bsmtp, "-") == 0) sinkfp = stdout; else sinkfp = fopen(ctl->bsmtp, "a"); /* see the ap computation under the SMTP branch */ fprintf(sinkfp, "MAIL FROM: %s", (msg->return_path[0]) ? msg->return_path : user); if (ctl->pass8bits || (ctl->mimemsg & MSG_IS_8BIT)) fputs(" BODY=8BITMIME", sinkfp); else if (ctl->mimemsg & MSG_IS_7BIT) fputs(" BODY=7BIT", sinkfp); /* exim's BSMTP processor does not handle SIZE */ /* fprintf(sinkfp, " SIZE=%d", msg->reallen); */ fprintf(sinkfp, "\r\n"); /* * RFC 1123 requires that the domain name part of the * RCPT TO address be "canonicalized", that is a FQDN * or MX but not a CNAME. Some listeners (like exim) * enforce this. Now that we have the actual hostname, * compute what we should canonicalize with. */ ctl->destaddr = ctl->smtpaddress ? ctl->smtpaddress : "localhost"; *bad_addresses = 0; for (idp = msg->recipients; idp; idp = idp->next) if (idp->val.status.mark == XMIT_ACCEPT) { if (ctl->smtpname) fprintf(sinkfp, "RCPT TO: %s\r\n", ctl->smtpname); else if (strchr(idp->id, '@')) fprintf(sinkfp, "RCPT TO: %s\r\n", idp->id); else fprintf(sinkfp, "RCPT TO: %s@%s\r\n", idp->id, ctl->destaddr); *good_addresses = 0; } fputs("DATA\r\n", sinkfp); if (ferror(sinkfp)) { report(stderr, GT_("BSMTP file open or preamble write failed\n")); return(PS_BSMTP); } return(PS_SUCCESS); } /* this is experimental and will be removed if double bounces are reported */ #define EXPLICIT_BOUNCE static int open_smtp_sink(struct query *ctl, struct msgblk *msg, int *good_addresses, int *bad_addresses) /* open an SMTP stream */ { const char *ap; struct idlist *idp; char options[MSGBUFSIZE]; char addr[HOSTLEN+USERNAMELEN+1]; #ifdef EXPLICIT_BOUNCE char **from_responses; #endif /* EXPLICIT_BOUNCE */ int total_addresses; /* * Compute ESMTP options. */ options[0] = '\0'; if (ctl->server.esmtp_options & ESMTP_8BITMIME) { if (ctl->pass8bits || (ctl->mimemsg & MSG_IS_8BIT)) strcpy(options, " BODY=8BITMIME"); else if (ctl->mimemsg & MSG_IS_7BIT) strcpy(options, " BODY=7BIT"); } if ((ctl->server.esmtp_options & ESMTP_SIZE) && msg->reallen > 0) sprintf(options + strlen(options), " SIZE=%d", msg->reallen); /* * Try to get the SMTP listener to take the Return-Path * address as MAIL FROM. If it won't, fall back on the * remotename and mailserver host. This won't affect replies, * which use the header From address anyway; the MAIL FROM * address is a place for the SMTP listener to send * bouncemail. The point is to guarantee a FQDN in the MAIL * FROM line -- some SMTP listeners, like smail, become * unhappy otherwise. * * RFC 1123 requires that the domain name part of the * MAIL FROM address be "canonicalized", that is a * FQDN or MX but not a CNAME. We'll assume the Return-Path * header is already in this form here (it certainly * is if rewrite is on). RFC 1123 is silent on whether * a nonexistent hostname part is considered canonical. * * This is a potential problem if the MTAs further upstream * didn't pass canonicalized From/Return-Path lines, *and* the * local SMTP listener insists on them. * * Handle the case where an upstream MTA is setting a return * path equal to "@". Ghod knows why anyone does this, but * it's been reported to happen in mail from Amazon.com and * Motorola. */ if (!msg->return_path[0] || (0 == strcmp(msg->return_path, "@"))) { #ifdef HAVE_SNPRINTF snprintf(addr, sizeof(addr), #else sprintf(addr, #endif /* HAVE_SNPRINTF */ "%s@%s", ctl->remotename, ctl->server.truename); ap = addr; } else if (strchr(msg->return_path,'@') || strchr(msg->return_path,'!')) ap = msg->return_path; else /* in case Return-Path existed but was local */ { #ifdef HAVE_SNPRINTF snprintf(addr, sizeof(addr), #else sprintf(addr, #endif /* HAVE_SNPRINTF */ "%s@%s", msg->return_path, ctl->server.truename); ap = addr; } if (SMTP_from(ctl->smtp_socket, ap, options) != SM_OK) { int err = handle_smtp_report(ctl, msg); SMTP_rset(ctl->smtp_socket); /* stay on the safe side */ return(err); } /* * Now list the recipient addressees */ total_addresses = 0; for (idp = msg->recipients; idp; idp = idp->next) total_addresses++; #ifdef EXPLICIT_BOUNCE_ON_BAD_ADDRESS xalloca(from_responses, char **, sizeof(char *) * total_addresses); #endif /* EXPLICIT_BOUNCE_ON_BAD_ADDRESS */ for (idp = msg->recipients; idp; idp = idp->next) if (idp->val.status.mark == XMIT_ACCEPT) { if (strchr(idp->id, '@')) strcpy(addr, idp->id); else { if (ctl->smtpname) { #ifdef HAVE_SNPRINTF snprintf(addr, sizeof(addr)-1, "%s", ctl->smtpname); #else sprintf(addr, "%s", ctl->smtpname); #endif /* HAVE_SNPRINTF */ } else { #ifdef HAVE_SNPRINTF snprintf(addr, sizeof(addr)-1, "%s@%s", idp->id, ctl->destaddr); #else sprintf(addr, "%s@%s", idp->id, ctl->destaddr); #endif /* HAVE_SNPRINTF */ } } if (SMTP_rcpt(ctl->smtp_socket, addr) == SM_OK) (*good_addresses)++; else { handle_smtp_report(ctl, msg); #ifdef EXPLICIT_BOUNCE_ON_BAD_ADDRESS #ifdef HAVE_SNPRINTF snprintf(errbuf, sizeof(errbuf), "%s: %s", idp->id, smtp_response); #else strncpy(errbuf, idp->id, sizeof(errbuf)); strcat(errbuf, ": "); strcat(errbuf, smtp_response); #endif /* HAVE_SNPRINTF */ xalloca(from_responses[*bad_addresses], char *, strlen(errbuf)+1); strcpy(from_responses[*bad_addresses], errbuf); #endif /* EXPLICIT_BOUNCE_ON_BAD_ADDRESS */ (*bad_addresses)++; idp->val.status.mark = XMIT_RCPTBAD; if (outlevel >= O_VERBOSE) report(stderr, GT_("%cMTP listener doesn't like recipient address `%s'\n"), ctl->listener, addr); } } #ifdef EXPLICIT_BOUNCE_ON_BAD_ADDRESS /* * This should not be necessary, because the SMTP listener itself * should genrate a bounce for the bad address. */ if (*bad_addresses) send_bouncemail(ctl, msg, XMIT_RCPTBAD, "Some addresses were rejected by the MDA fetchmail forwards to.\r\n", *bad_addresses, from_responses); #endif /* EXPLICIT_BOUNCE_ON_BAD_ADDRESS */ /* * It's tempting to do local notification only if bouncemail was * insufficient -- that is, to add && total_addresses > *bad_addresses * to the test here. The problem with this theory is that it would * make initial diagnosis of a broken multidrop configuration very * hard -- most single-recipient messages would just invisibly bounce. */ if (!(*good_addresses)) { if (!run.postmaster[0]) { if (outlevel >= O_VERBOSE) report(stderr, GT_("no address matches; no postmaster set.\n")); SMTP_rset(ctl->smtp_socket); /* required by RFC1870 */ return(PS_REFUSED); } if (strchr(run.postmaster, '@')) strncpy(addr, run.postmaster, sizeof(addr)); else { #ifdef HAVE_SNPRINTF snprintf(addr, sizeof(addr)-1, "%s@%s", run.postmaster, ctl->destaddr); #else sprintf(addr, "%s@%s", run.postmaster, ctl->destaddr); #endif /* HAVE_SNPRINTF */ } if (SMTP_rcpt(ctl->smtp_socket, addr) != SM_OK) { report(stderr, GT_("can't even send to %s!\n"), run.postmaster); SMTP_rset(ctl->smtp_socket); /* required by RFC1870 */ return(PS_REFUSED); } if (outlevel >= O_VERBOSE) report(stderr, GT_("no address matches; forwarding to %s.\n"), run.postmaster); } /* * Tell the listener we're ready to send data. * Some listeners (like zmailer) may return antispam errors here. */ if (SMTP_data(ctl->smtp_socket) != SM_OK) { SMTP_rset(ctl->smtp_socket); /* stay on the safe side */ return(handle_smtp_report(ctl, msg)); } } static int open_mda_sink(struct query *ctl, struct msgblk *msg, int *good_addresses, int *bad_addresses) /* open a stream to a local MDA */ { #ifdef HAVE_SIGACTION struct sigaction sa_new; #endif /* HAVE_SIGACTION */ struct idlist *idp; int length = 0, fromlen = 0, nameslen = 0; char *names = NULL, *before, *after, *from = NULL; ctl->destaddr = "localhost"; for (idp = msg->recipients; idp; idp = idp->next) if (idp->val.status.mark == XMIT_ACCEPT) (*good_addresses)++; length = strlen(ctl->mda); before = xstrdup(ctl->mda); /* get user addresses for %T (or %s for backward compatibility) */ if (strstr(before, "%s") || strstr(before, "%T")) { /* * We go through this in order to be able to handle very * long lists of users and (re)implement %s. */ nameslen = 0; for (idp = msg->recipients; idp; idp = idp->next) if ((idp->val.status.mark == XMIT_ACCEPT)) nameslen += (strlen(idp->id) + 1); /* string + ' ' */ if ((*good_addresses == 0)) nameslen = strlen(run.postmaster); names = (char *)xmalloc(nameslen + 1); /* account for '\0' */ if (*good_addresses == 0) strcpy(names, run.postmaster); else { names[0] = '\0'; for (idp = msg->recipients; idp; idp = idp->next) if (idp->val.status.mark == XMIT_ACCEPT) { strcat(names, idp->id); strcat(names, " "); } names[--nameslen] = '\0'; /* chop trailing space */ } /* sanitize names in order to contain only harmless shell chars */ sanitize(names); } /* get From address for %F */ if (strstr(before, "%F")) { from = xstrdup(msg->return_path); /* sanitize from in order to contain *only* harmless shell chars */ sanitize(from); fromlen = strlen(from); } /* do we have to build an mda string? */ if (names || from) { char *sp, *dp; /* find length of resulting mda string */ sp = before; while ((sp = strstr(sp, "%s"))) { length += nameslen - 2; /* subtract %s */ sp += 2; } sp = before; while ((sp = strstr(sp, "%T"))) { length += nameslen - 2; /* subtract %T */ sp += 2; } sp = before; while ((sp = strstr(sp, "%F"))) { length += fromlen - 2; /* subtract %F */ sp += 2; } after = xmalloc(length + 1); /* copy mda source string to after, while expanding %[sTF] */ for (dp = after, sp = before; (*dp = *sp); dp++, sp++) { if (sp[0] != '%') continue; /* need to expand? BTW, no here overflow, because in ** the worst case (end of string) sp[1] == '\0' */ if (sp[1] == 's' || sp[1] == 'T') { strcpy(dp, names); dp += nameslen; sp++; /* position sp over [sT] */ dp--; /* adjust dp */ } else if (sp[1] == 'F') { strcpy(dp, from); dp += fromlen; sp++; /* position sp over F */ dp--; /* adjust dp */ } } if (names) { free(names); names = NULL; } if (from) { free(from); from = NULL; } free(before); before = after; } if (outlevel >= O_DEBUG) report(stdout, GT_("about to deliver with: %s\n"), before); #ifdef HAVE_SETEUID /* * Arrange to run with user's permissions if we're root. * This will initialize the ownership of any files the * MDA creates properly. (The seteuid call is available * under all BSDs and Linux) */ seteuid(ctl->uid); #endif /* HAVE_SETEUID */ sinkfp = popen(before, "w"); free(before); before = NULL; #ifdef HAVE_SETEUID /* this will fail quietly if we didn't start as root */ seteuid(0); #endif /* HAVE_SETEUID */ if (!sinkfp) { report(stderr, GT_("MDA open failed\n")); return(PS_IOERR); } /* * We need to disable the normal SIGCHLD handling here because * sigchld_handler() would reap away the error status, returning * error status instead of 0 for successful completion. */ #ifndef HAVE_SIGACTION sigchld = signal(SIGCHLD, SIG_DFL); #else memset (&sa_new, 0, sizeof sa_new); sigemptyset (&sa_new.sa_mask); sa_new.sa_handler = SIG_DFL; sigaction (SIGCHLD, &sa_new, NULL); #endif /* HAVE_SIGACTION */ } int open_sink(struct query *ctl, struct msgblk *msg, int *good_addresses, int *bad_addresses) /* set up sinkfp to be an input sink we can ship a message to */ { *bad_addresses = *good_addresses = 0; if (ctl->bsmtp) /* dump to a BSMTP batch file */ return(open_bsmtp_sink(ctl, msg, good_addresses, bad_addresses)); /* * Try to forward to an SMTP or LMTP listener. If the attempt to * open a socket fails, fall through to attempt delivery via * local MDA. */ else if (!ctl->mda && smtp_open(ctl) != -1) return(open_smtp_sink(ctl, msg, good_addresses, bad_addresses)); /* * Awkward case. User didn't specify an MDA. Our attempt to get a * listener socket failed. Try to cope anyway -- initial configuration * may have found procmail. */ else if (!ctl->mda) { report(stderr, GT_("%cMTP connect to %s failed\n"), ctl->listener, ctl->smtphost ? ctl->smtphost : "localhost"); #ifndef FALLBACK_MDA /* No fallback MDA declared. Bail out. */ return(PS_SMTP); #else /* * If user had things set up to forward offsite, no way * we want to deliver locally! */ if (ctl->smtphost && strcmp(ctl->smtphost, "localhost")) return(PS_SMTP); /* * User was delivering locally. We have a fallback MDA. * Latch it in place, logging the error, and fall through. */ ctl->mda = FALLBACK_MDA; report(stderr, GT_("can't raise the listener; falling back to %s"), FALLBACK_MDA); #endif } if (ctl->mda) /* must deliver through an MDA */ return(open_mda_sink(ctl, msg, good_addresses, bad_addresses)); /* * We need to stash this away in order to know how many * response lines to expect after the LMTP end-of-message. */ lmtp_responses = *good_addresses; return(PS_SUCCESS); } void release_sink(struct query *ctl) /* release the per-message output sink, whether it's a pipe or SMTP socket */ { if (ctl->bsmtp && sinkfp) fclose(sinkfp); else if (ctl->mda) { if (sinkfp) { pclose(sinkfp); sinkfp = (FILE *)NULL; } deal_with_sigchld(); /* Restore SIGCHLD handling to reap zombies */ } } int close_sink(struct query *ctl, struct msgblk *msg, flag forward) /* perform end-of-message actions on the current output sink */ { if (ctl->mda) { int rc; /* close the delivery pipe, we'll reopen before next message */ if (sinkfp) { rc = pclose(sinkfp); sinkfp = (FILE *)NULL; } else rc = 0; deal_with_sigchld(); /* Restore SIGCHLD handling to reap zombies */ if (rc) { report(stderr, GT_("MDA returned nonzero status %d\n"), rc); return(FALSE); } } else if (ctl->bsmtp && sinkfp) { int error; /* implicit disk-full check here... */ fputs(".\r\n", sinkfp); error = ferror(sinkfp); if (strcmp(ctl->bsmtp, "-")) if (fclose(sinkfp) == EOF) error = 1; if (error) { report(stderr, GT_("Message termination or close of BSMTP file failed\n")); return(FALSE); } } else if (forward) { /* write message terminator */ if (SMTP_eom(ctl->smtp_socket) != SM_OK) { if (handle_smtp_report(ctl, msg) != PS_REFUSED) { SMTP_rset(ctl->smtp_socket); /* stay on the safe side */ return(FALSE); } else { report(stderr, GT_("SMTP listener refused delivery\n")); SMTP_rset(ctl->smtp_socket); /* stay on the safe side */ return(TRUE); } } /* * If this is an SMTP connection, SMTP_eom() ate the response. * But could be this is an LMTP connection, in which case we have to * interpret either (a) a single 503 response meaning there * were no successful RCPT TOs, or (b) a variable number of * responses, one for each successful RCPT TO. We need to send * bouncemail on each failed response and then return TRUE anyway, * otherwise the message will get left in the queue and resent * to people who got it the first time. */ if (ctl->listener == LMTP_MODE) { if (lmtp_responses == 0) { SMTP_ok(ctl->smtp_socket); /* * According to RFC2033, 503 is the only legal response * if no RCPT TO commands succeeded. No error recovery * is really possible here, as we have no idea what * insane thing the listener might be doing if it doesn't * comply. */ if (atoi(smtp_response) == 503) report(stderr, GT_("LMTP delivery error on EOM\n")); else report(stderr, GT_("Unexpected non-503 response to LMTP EOM: %s\n"), smtp_response); /* * It's not completely clear what to do here. We choose to * interpret delivery failure here as a transient error, * the same way SMTP delivery failure is handled. If we're * wrong, an undead message will get stuck in the queue. */ return(FALSE); } else { int i, errors; char **responses; /* eat the RFC2033-required responses, saving errors */ xalloca(responses, char **, sizeof(char *) * lmtp_responses); for (errors = i = 0; i < lmtp_responses; i++) { if (SMTP_ok(ctl->smtp_socket) == SM_OK) responses[i] = (char *)NULL; else { xalloca(responses[errors], char *, strlen(smtp_response)+1); strcpy(responses[errors], smtp_response); errors++; } } if (errors == 0) return(TRUE); /* all deliveries succeeded */ else /* * One or more deliveries failed. * If we can bounce a failures list back to the * sender, and the postmaster does not want to * deal with the bounces return TRUE, deleting the * message from the server so it won't be * re-forwarded on subsequent poll cycles. */ return(send_bouncemail(ctl, msg, XMIT_ACCEPT, "LSMTP partial delivery failure.\r\n", errors, responses)); } } } return(TRUE); } int open_warning_by_mail(struct query *ctl, struct msgblk *msg) /* set up output sink for a mailed warning to calling user */ { int good, bad; /* * Dispatching warning email is a little complicated. The problem is * that we have to deal with three distinct cases: * * 1. Single-drop running from user account. Warning mail should * go to the local name for which we're collecting (coincides * with calling user). * * 2. Single-drop running from root or other privileged ID, with rc * file generated on the fly (Ken Estes's weird setup...) Mail * should go to the local name for which we're collecting (does not * coincide with calling user). * * 3. Multidrop. Mail must go to postmaster. We leave the recipients * member null so this message will fall through to run.postmaster. * * The zero in the reallen element means we won't pass a SIZE * option to ESMTP; the message length would be more trouble than * it's worth to compute. */ struct msgblk reply = {NULL, NULL, "FETCHMAIL-DAEMON@", 0}; int status; strcat(reply.return_path, fetchmailhost); if (!MULTIDROP(ctl)) /* send to calling user */ { save_str(&reply.recipients, ctl->localnames->id, XMIT_ACCEPT); status = open_sink(ctl, &reply, &good, &bad); free_str_list(&reply.recipients); } else /* send to postmaster */ status = open_sink(ctl, &reply, &good, &bad); stuff_warning(ctl, "Date: %s", rfc822timestamp()); return(status); } #if defined(HAVE_STDARG_H) void stuff_warning(struct query *ctl, const char *fmt, ... ) #else void stuff_warning(struct query *ctl, fmt, va_alist) struct query *ctl; const char *fmt; /* printf-style format */ va_dcl #endif /* format and ship a warning message line by mail */ { char buf[POPBUFSIZE]; va_list ap; /* * stuffline() requires its input to be writeable (for CR stripping), * so we needed to copy the message to a writeable buffer anyway in * case it was a string constant. We make a virtue of that necessity * here by supporting stdargs/varargs. */ #if defined(HAVE_STDARG_H) va_start(ap, fmt) ; #else va_start(ap); #endif #ifdef HAVE_VSNPRINTF vsnprintf(buf, sizeof(buf), fmt, ap); #else vsprintf(buf, fmt, ap); #endif va_end(ap); #ifdef HAVE_SNPRINTF snprintf(buf+strlen(buf), sizeof(buf)-strlen(buf), "\r\n"); #else strcat(buf, "\r\n"); #endif /* HAVE_SNPRINTF */ stuffline(ctl, buf); } void close_warning_by_mail(struct query *ctl, struct msgblk *msg) /* sign and send mailed warnings */ { stuff_warning(ctl, GT_("--\r\n\t\t\t\tThe Fetchmail Daemon\r\n")); close_sink(ctl, msg, TRUE); } /* sink.c ends here */