/* $OpenBSD: mta.c,v 1.9 2008/12/05 19:09:59 gilles Exp $ */ /* * Copyright (c) 2008 Pierre-Yves Ritschard * Copyright (c) 2008 Gilles Chehade * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "smtpd.h" __dead void mta_shutdown(void); void mta_sig_handler(int, short, void *); void mta_dispatch_parent(int, short, void *); void mta_dispatch_queue(int, short, void *); void mta_dispatch_runner(int, short, void *); void mta_setup_events(struct smtpd *); void mta_disable_events(struct smtpd *); void mta_timeout(int, short, void *); void mta_write(int, short, void *); int mta_connect(struct batch *); void mta_read_handler(struct bufferevent *, void *); void mta_write_handler(struct bufferevent *, void *); void mta_error_handler(struct bufferevent *, short, void *); int mta_reply_handler(struct bufferevent *, void *); void mta_batch_update_queue(struct batch *); void mta_sig_handler(int sig, short event, void *p) { switch (sig) { case SIGINT: case SIGTERM: mta_shutdown(); break; default: fatalx("mta_sig_handler: unexpected signal"); } } void mta_dispatch_parent(int sig, short event, void *p) { struct smtpd *env = p; struct imsgbuf *ibuf; struct imsg imsg; ssize_t n; ibuf = env->sc_ibufs[PROC_PARENT]; switch (event) { case EV_READ: if ((n = imsg_read(ibuf)) == -1) fatal("imsg_read_error"); if (n == 0) { /* this pipe is dead, so remove the event handler */ event_del(&ibuf->ev); event_loopexit(NULL); return; } break; case EV_WRITE: if (msgbuf_write(&ibuf->w) == -1) fatal("msgbuf_write"); imsg_event_add(ibuf); return; default: fatalx("unknown event"); } for (;;) { if ((n = imsg_get(ibuf, &imsg)) == -1) fatal("parent_dispatch_mta: imsg_read error"); if (n == 0) break; switch (imsg.hdr.type) { default: log_debug("parent_dispatch_mta: unexpected imsg %d", imsg.hdr.type); break; } imsg_free(&imsg); } imsg_event_add(ibuf); } void mta_dispatch_queue(int sig, short event, void *p) { struct smtpd *env = p; struct imsgbuf *ibuf; struct imsg imsg; ssize_t n; ibuf = env->sc_ibufs[PROC_QUEUE]; switch (event) { case EV_READ: if ((n = imsg_read(ibuf)) == -1) fatal("imsg_read_error"); if (n == 0) { /* this pipe is dead, so remove the event handler */ event_del(&ibuf->ev); event_loopexit(NULL); return; } break; case EV_WRITE: if (msgbuf_write(&ibuf->w) == -1) fatal("msgbuf_write"); imsg_event_add(ibuf); return; default: fatalx("unknown event"); } for (;;) { if ((n = imsg_get(ibuf, &imsg)) == -1) fatal("parent_dispatch_mta: imsg_read error"); if (n == 0) break; switch (imsg.hdr.type) { case IMSG_QUEUE_MESSAGE_FD: { struct batch *batchp; int fd; if ((fd = imsg_get_fd(ibuf, &imsg)) == -1) { /* NEEDS_FIX - unsure yet how it must be handled */ fatalx("mta_dispatch_queue: imsg_get_fd"); } batchp = (struct batch *)imsg.data; batchp = batch_by_id(env, batchp->id); if ((batchp->messagefp = fdopen(fd, "r")) == NULL) fatal("mta_dispatch_queue: fdopen"); evbuffer_add_printf(batchp->bev->output, "DATA\r\n"); bufferevent_enable(batchp->bev, EV_WRITE|EV_READ); break; } default: log_debug("parent_dispatch_mta: unexpected imsg %d", imsg.hdr.type); break; } imsg_free(&imsg); } imsg_event_add(ibuf); } void mta_dispatch_runner(int sig, short event, void *p) { struct smtpd *env = p; struct imsgbuf *ibuf; struct imsg imsg; ssize_t n; ibuf = env->sc_ibufs[PROC_RUNNER]; switch (event) { case EV_READ: if ((n = imsg_read(ibuf)) == -1) fatal("imsg_read_error"); if (n == 0) { /* this pipe is dead, so remove the event handler */ event_del(&ibuf->ev); event_loopexit(NULL); return; } break; case EV_WRITE: if (msgbuf_write(&ibuf->w) == -1) fatal("msgbuf_write"); imsg_event_add(ibuf); return; default: fatalx("unknown event"); } for (;;) { if ((n = imsg_get(ibuf, &imsg)) == -1) fatal("mta_dispatch_runner: imsg_read error"); if (n == 0) break; switch (imsg.hdr.type) { case IMSG_CREATE_BATCH: { struct batch *batchp; batchp = calloc(1, sizeof (struct batch)); if (batchp == NULL) fatal("mta_dispatch_runner: calloc"); *batchp = *(struct batch *)imsg.data; batchp->mx_off = 0; batchp->env = env; batchp->flags = 0; TAILQ_INIT(&batchp->messages); SPLAY_INSERT(batchtree, &env->batch_queue, batchp); break; } case IMSG_BATCH_APPEND: { struct batch *batchp; struct message *messagep; messagep = calloc(1, sizeof (struct message)); if (messagep == NULL) fatal("mta_dispatch_runner: calloc"); *messagep = *(struct message *)imsg.data; batchp = batch_by_id(env, messagep->batch_id); if (batchp == NULL) fatalx("mta_dispatch_runner: internal inconsistency."); TAILQ_INSERT_TAIL(&batchp->messages, messagep, entry); break; } case IMSG_BATCH_CLOSE: { struct batch *batchp; batchp = (struct batch *)imsg.data; batchp = batch_by_id(env, batchp->id); if (batchp == NULL) fatalx("mta_dispatch_runner: internal inconsistency."); batchp->flags |= F_BATCH_COMPLETE; while (! mta_connect(batchp)) { if (batchp->mx_off == batchp->mx_cnt) { break; } } break; } default: log_debug("mta_dispatch_runner: unexpected imsg %d", imsg.hdr.type); break; } imsg_free(&imsg); } imsg_event_add(ibuf); } void mta_shutdown(void) { log_info("mail transfer agent exiting"); _exit(0); } void mta_setup_events(struct smtpd *env) { struct timeval tv; evtimer_set(&env->sc_ev, mta_timeout, env); tv.tv_sec = 3; tv.tv_usec = 0; evtimer_add(&env->sc_ev, &tv); } void mta_disable_events(struct smtpd *env) { evtimer_del(&env->sc_ev); } void mta_timeout(int fd, short event, void *p) { struct smtpd *env = p; struct timeval tv; tv.tv_sec = 3; tv.tv_usec = 0; evtimer_add(&env->sc_ev, &tv); } pid_t mta(struct smtpd *env) { pid_t pid; struct passwd *pw; struct event ev_sigint; struct event ev_sigterm; struct peer peers[] = { { PROC_QUEUE, mta_dispatch_queue }, { PROC_RUNNER, mta_dispatch_runner } }; switch (pid = fork()) { case -1: fatal("mta: cannot fork"); case 0: break; default: return (pid); } purge_config(env, PURGE_EVERYTHING); pw = env->sc_pw; #ifndef DEBUG if (chroot(pw->pw_dir) == -1) fatal("mta: chroot"); if (chdir("/") == -1) fatal("mta: chdir(\"/\")"); #else #warning disabling privilege revocation and chroot in DEBUG MODE #endif setproctitle("mail transfer agent"); smtpd_process = PROC_MTA; #ifndef DEBUG if (setgroups(1, &pw->pw_gid) || setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) || setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid)) fatal("mta: cannot drop privileges"); #endif event_init(); signal_set(&ev_sigint, SIGINT, mta_sig_handler, env); signal_set(&ev_sigterm, SIGTERM, mta_sig_handler, env); signal_add(&ev_sigint, NULL); signal_add(&ev_sigterm, NULL); signal(SIGPIPE, SIG_IGN); signal(SIGHUP, SIG_IGN); config_peers(env, peers, 2); SPLAY_INIT(&env->batch_queue); mta_setup_events(env); event_dispatch(); mta_shutdown(); return (0); } /* shamelessly ripped usr.sbin/relayd/check_tcp.c ;) */ int mta_connect(struct batch *batchp) { int s; int type; struct linger lng; struct sockaddr_in ssin; struct sockaddr_in6 ssin6; if ((s = socket(batchp->mxarray[batchp->mx_off].ss.ss_family, SOCK_STREAM, 0)) == -1) { goto bad; } bzero(&lng, sizeof(lng)); if (setsockopt(s, SOL_SOCKET, SO_LINGER, &lng, sizeof (lng)) == -1) { goto bad; } type = 1; if (setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &type, sizeof (type)) == -1) { goto bad; } session_socket_blockmode(s, BM_NONBLOCK); if (batchp->mxarray[batchp->mx_off].ss.ss_family == PF_INET) { ssin = *(struct sockaddr_in *)&batchp->mxarray[batchp->mx_off].ss; if (connect(s, (struct sockaddr *)&ssin, sizeof(struct sockaddr_in)) == -1) { if (errno != EINPROGRESS) { goto bad; } } } if (batchp->mxarray[batchp->mx_off].ss.ss_family == PF_INET6) { ssin6 = *(struct sockaddr_in6 *)&batchp->mxarray[batchp->mx_off].ss; if (connect(s, (struct sockaddr *)&ssin6, sizeof(struct sockaddr_in6)) == -1) { if (errno != EINPROGRESS) { goto bad; } } } batchp->tv.tv_sec = SMTPD_CONNECT_TIMEOUT; batchp->tv.tv_usec = 0; batchp->peerfd = s; event_set(&batchp->ev, s, EV_TIMEOUT|EV_WRITE, mta_write, batchp); event_add(&batchp->ev, &batchp->tv); return 1; bad: batchp->mx_off++; close(s); return 0; } void mta_write(int s, short event, void *arg) { struct batch *batchp = arg; int ret; if (event == EV_TIMEOUT) { batchp->mx_off++; close(s); if (batchp->bev) { bufferevent_free(batchp->bev); batchp->bev = NULL; } strlcpy(batchp->errorline, "connection timed-out.", MAX_LINE_SIZE); ret = 0; while (batchp->mx_off < batchp->mx_cnt && (ret = mta_connect(batchp)) == 0) { continue; } if (ret) return; mta_batch_update_queue(batchp); return; } batchp->bev = bufferevent_new(s, mta_read_handler, mta_write_handler, mta_error_handler, batchp); if (batchp->bev == NULL) { mta_batch_update_queue(batchp); close(s); return; } bufferevent_enable(batchp->bev, EV_READ|EV_WRITE); } void mta_read_handler(struct bufferevent *bev, void *arg) { while (mta_reply_handler(bev, arg)) ; } int mta_reply_handler(struct bufferevent *bev, void *arg) { struct batch *batchp = arg; struct smtpd *env = batchp->env; struct message *messagep = NULL; char *line; int i; int code; #define F_ISINFO 0x1 #define F_ISPROTOERROR 0x2 char codebuf[4]; const char *errstr; int flags = 0; line = evbuffer_readline(bev->input); if (line == NULL) { bufferevent_enable(bev, EV_READ|EV_WRITE); return 0; } line[strcspn(line, "\r")] = '\0'; bufferevent_enable(bev, EV_READ|EV_WRITE); log_debug("remote server sent: [%s]", line); strlcpy(codebuf, line, sizeof codebuf); code = strtonum(codebuf, 0, UINT16_MAX, &errstr); if (errstr || code < 100) { /* Server sent invalid line, protocol error */ batchp->status |= S_BATCH_PERMFAILURE; strlcpy(batchp->errorline, line, MAX_LINE_SIZE); mta_batch_update_queue(batchp); return 0; } if (line[3] == '-') { return 1; } switch (code) { case 250: if (batchp->state == S_DONE) { mta_batch_update_queue(batchp); return 0; } break; case 220: evbuffer_add_printf(batchp->bev->output, "EHLO %s\r\n", env->sc_hostname); batchp->state = S_GREETED; return 1; case 421: case 450: case 451: batchp->status |= S_BATCH_TEMPFAILURE; strlcpy(batchp->errorline, line, MAX_LINE_SIZE); mta_batch_update_queue(batchp); return 0; /* The following codes are state dependant and will cause * a batch rejection if returned at the wrong state. */ case 530: case 550: if (batchp->state == S_RCPT) { batchp->messagep->status = (S_MESSAGE_REJECTED|S_MESSAGE_PERMFAILURE); strlcpy(batchp->messagep->session_errorline, line, MAX_LINE_SIZE); break; } case 354: if (batchp->state == S_RCPT && batchp->messagep == NULL) { batchp->state = S_DATA; break; } case 221: if (batchp->state == S_DONE) { mta_batch_update_queue(batchp); return 0; } case 552: case 553: flags |= F_ISPROTOERROR; default: /* Server sent code we know nothing about, error */ if (!(flags & F_ISPROTOERROR)) log_debug("Ouch, SMTP session returned unhandled %d status.", code); batchp->status |= S_BATCH_PERMFAILURE; strlcpy(batchp->errorline, line, MAX_LINE_SIZE); mta_batch_update_queue(batchp); return 0; } switch (batchp->state) { case S_GREETED: { char *user; char *domain; if (batchp->type & T_DAEMON_BATCH) { user = "MAILER-DAEMON"; domain = env->sc_hostname; } else { messagep = TAILQ_FIRST(&batchp->messages); user = messagep->sender.user; domain = messagep->sender.domain; } if (user[0] == '\0' && domain[0] == '\0') evbuffer_add_printf(batchp->bev->output, "MAIL FROM:<>\r\n"); else evbuffer_add_printf(batchp->bev->output, "MAIL FROM:<%s@%s>\r\n", user, domain); batchp->state = S_MAIL; break; } case S_MAIL: batchp->state = S_RCPT; case S_RCPT: { char *user; char *domain; /* Is this the first RCPT ? */ if (batchp->messagep == NULL) messagep = TAILQ_FIRST(&batchp->messages); else { /* We already had a RCPT, mark is as accepted and * fetch next one from queue if we aren't dealing * with a daemon batch. */ if (batchp->type & T_DAEMON_BATCH) messagep = NULL; else { messagep = batchp->messagep; if ((messagep->status & S_MESSAGE_REJECTED) == 0) messagep->status = S_MESSAGE_ACCEPTED; messagep = TAILQ_NEXT(batchp->messagep, entry); } } batchp->messagep = messagep; if (messagep) { if (batchp->type & T_DAEMON_BATCH) { user = messagep->sender.user; domain = messagep->sender.domain; } else { user = messagep->recipient.user; domain = messagep->recipient.domain; } evbuffer_add_printf(batchp->bev->output, "RCPT TO:<%s@%s>\r\n", user, domain); } else { /* Do we have at least one accepted recipient ? */ if ((batchp->type & T_DAEMON_BATCH) == 0) { TAILQ_FOREACH(messagep, &batchp->messages, entry) { if (messagep->status & S_MESSAGE_ACCEPTED) break; } if (messagep == NULL) { batchp->status |= S_BATCH_PERMFAILURE; mta_batch_update_queue(batchp); return 0; } } bufferevent_disable(batchp->bev, EV_WRITE|EV_READ); imsg_compose(env->sc_ibufs[PROC_QUEUE], IMSG_QUEUE_MESSAGE_FD, 0, 0, -1, batchp, sizeof(*batchp)); } break; } case S_DATA: { bufferevent_enable(batchp->bev, EV_READ|EV_WRITE); evbuffer_add_printf(batchp->bev->output, "Received: from %s (%s [%s])\r\n" "\tby %s with ESMTP id %s\r\n", "localhost", "localhost", "127.0.0.1", "", batchp->message_id); evbuffer_add_printf(batchp->bev->output, "X-OpenSMTPD: experiment\r\n"); if (batchp->type & T_DAEMON_BATCH) { evbuffer_add_printf(batchp->bev->output, "Hi !\r\n\r\n" "This is the MAILER-DAEMON, please DO NOT REPLY to this e-mail it is\r\n" "just a notification to let you know that an error has occured.\r\n\r\n"); if (batchp->status & S_BATCH_PERMFAILURE) { evbuffer_add_printf(batchp->bev->output, "You ran into a PERMANENT FAILURE, which means that the e-mail can't\r\n" "be delivered to the remote host no matter how much I'll try.\r\n\r\n" "Diagnostic:\r\n" "%s\r\n\r\n", batchp->errorline); } if (batchp->status & S_BATCH_TEMPFAILURE) { evbuffer_add_printf(batchp->bev->output, "You ran into a TEMPORARY FAILURE, which means that the e-mail can't\r\n" "be delivered right now, but could be deliberable at a later time. I\r\n" "will attempt until it succeeds for the next four days, then let you\r\n" "know if it didn't work out.\r\n" "Diagnostic:\r\n" "%s\r\n\r\n", batchp->errorline); } i = 0; TAILQ_FOREACH(messagep, &batchp->messages, entry) { if (messagep->status & S_MESSAGE_TEMPFAILURE) { if (i == 0) { evbuffer_add_printf(batchp->bev->output, "The following recipients caused a temporary failure:\r\n"); ++i; } evbuffer_add_printf(batchp->bev->output, "\t<%s@%s>:\r\n%s\r\n\r\n", messagep->recipient.user, messagep->recipient.domain, messagep->session_errorline); } } i = 0; TAILQ_FOREACH(messagep, &batchp->messages, entry) { if (messagep->status & S_MESSAGE_PERMFAILURE) { if (i == 0) { evbuffer_add_printf(batchp->bev->output, "The following recipients caused a permanent failure:\r\n"); ++i; } evbuffer_add_printf(batchp->bev->output, "\t<%s@%s>:\r\n%s\r\n\r\n", messagep->recipient.user, messagep->recipient.domain, messagep->session_errorline); } } evbuffer_add_printf(batchp->bev->output, "Below is a copy of the original message:\r\n\r\n"); } break; } case S_DONE: evbuffer_add_printf(batchp->bev->output, "QUIT\r\n"); batchp->state = S_QUIT; break; default: log_info("unknown command: %d", batchp->state); } return 1; } void mta_write_handler(struct bufferevent *bev, void *arg) { struct batch *batchp = arg; char *buf, *lbuf; size_t len; if (batchp->state == S_QUIT) { bufferevent_disable(bev, EV_READ|EV_WRITE); log_debug("closing connection because of QUIT"); close(batchp->peerfd); return; } /* Progressively fill the output buffer with data */ if (batchp->state == S_DATA) { lbuf = NULL; if ((buf = fgetln(batchp->messagefp, &len))) { if (buf[len - 1] == '\n') buf[len - 1] = '\0'; else { if ((lbuf = malloc(len + 1)) == NULL) fatal("mta_write_handler: malloc"); memcpy(lbuf, buf, len); lbuf[len] = '\0'; buf = lbuf; } evbuffer_add_printf(batchp->bev->output, "%s\r\n", buf); free(lbuf); lbuf = NULL; } else { evbuffer_add_printf(batchp->bev->output, ".\r\n"); batchp->state = S_DONE; fclose(batchp->messagefp); batchp->messagefp = NULL; } } bufferevent_enable(batchp->bev, EV_READ|EV_WRITE); } void mta_error_handler(struct bufferevent *bev, short error, void *arg) { struct batch *batchp = arg; if (error & (EVBUFFER_TIMEOUT|EVBUFFER_EOF)) { bufferevent_disable(bev, EV_READ|EV_WRITE); log_debug("closing connection because of an error"); close(batchp->peerfd); return; } } void mta_batch_update_queue(struct batch *batchp) { struct smtpd *env = batchp->env; struct message *messagep; while ((messagep = TAILQ_FIRST(&batchp->messages)) != NULL) { if (batchp->status & S_BATCH_PERMFAILURE) { messagep->status |= S_MESSAGE_PERMFAILURE; } if (batchp->status & S_BATCH_TEMPFAILURE) { if (messagep->status != S_MESSAGE_PERMFAILURE) messagep->status |= S_MESSAGE_TEMPFAILURE; } imsg_compose(env->sc_ibufs[PROC_QUEUE], IMSG_QUEUE_MESSAGE_UPDATE, 0, 0, -1, messagep, sizeof(struct message)); TAILQ_REMOVE(&batchp->messages, messagep, entry); free(messagep); } SPLAY_REMOVE(batchtree, &env->batch_queue, batchp); if (batchp->messagefp) fclose(batchp->messagefp); if (batchp->bev) bufferevent_free(batchp->bev); if (batchp->peerfd != -1) close(batchp->peerfd); free(batchp); }