X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/f07babc0c0abfe8328da451f91f3ea46df3e63d9..6f97d821f13060b234c3d272d7672558bb2365ae:/src/src/daemon.c diff --git a/src/src/daemon.c b/src/src/daemon.c index cb0d4af09..f40a58c75 100644 --- a/src/src/daemon.c +++ b/src/src/daemon.c @@ -3,6 +3,7 @@ *************************************************/ /* Copyright (c) University of Cambridge 1995 - 2018 */ +/* Copyright (c) The Exim Maintainers 2020 */ /* See the file NOTICE for conditions of use and distribution. */ /* Functions concerned with running Exim as a daemon */ @@ -58,7 +59,6 @@ Returns: nothing static void sighup_handler(int sig) { -sig = sig; /* Keep picky compilers happy */ sighup_seen = TRUE; signal(SIGHUP, sighup_handler); } @@ -82,7 +82,6 @@ Returns: nothing static void main_sigchld_handler(int sig) { -sig = sig; /* Keep picky compilers happy */ os_non_restarting_signal(SIGCHLD, SIG_DFL); sigchld_seen = TRUE; } @@ -129,11 +128,30 @@ if (smtp_out) smtp_printf("421 %s\r\n", FALSE, smtp_msg); /************************************************* *************************************************/ +#ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS +static void +unlink_notifier_socket(void) +{ +uschar * s = expand_string(notifier_socket); +DEBUG(D_any) debug_printf("unlinking notifier socket %s\n", s); +Uunlink(s); +} +#endif + + static void close_daemon_sockets(int daemon_notifier_fd, int * listen_sockets, int listen_socket_count) { -if (daemon_notifier_fd >= 0) (void) close(daemon_notifier_fd); +if (daemon_notifier_fd >= 0) + { + (void) close(daemon_notifier_fd); + daemon_notifier_fd = -1; +#ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS + unlink_notifier_socket(); +#endif + } + for (int i = 0; i < listen_socket_count; i++) (void) close(listen_sockets[i]); } @@ -277,10 +295,10 @@ to provide host-specific limits according to $sender_host address, but because this is in the daemon mainline, only fast expansions (such as inline address checks) should be used. The documentation is full of warnings. */ -if (smtp_accept_max_per_host != NULL) +if (smtp_accept_max_per_host) { uschar *expanded = expand_string(smtp_accept_max_per_host); - if (expanded == NULL) + if (!expanded) { if (!f.expand_string_forcedfail) log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host " @@ -292,7 +310,7 @@ if (smtp_accept_max_per_host != NULL) uschar *s = expanded; while (isdigit(*s)) max_for_this_host = max_for_this_host * 10 + *s++ - '0'; - if (*s != 0) + if (*s) log_write(0, LOG_MAIN|LOG_PANIC, "expansion of smtp_accept_max_per_host " "for %s contains non-digit: %s", whofrom->s, expanded); } @@ -302,8 +320,7 @@ if (smtp_accept_max_per_host != NULL) per host_address checks. Note that at this stage smtp_accept_count contains the count of *other* connections, not including this one. */ -if ((max_for_this_host > 0) && - (smtp_accept_count >= max_for_this_host)) +if (max_for_this_host > 0 && smtp_accept_count >= max_for_this_host) { int host_accept_count = 0; int other_host_count = 0; /* keep a count of non matches to optimise */ @@ -320,8 +337,8 @@ if ((max_for_this_host > 0) && early, either by hitting the target, or finding there are not enough connections left to make the target. */ - if ((host_accept_count >= max_for_this_host) || - ((smtp_accept_count - other_host_count) < max_for_this_host)) + if ( host_accept_count >= max_for_this_host + || smtp_accept_count - other_host_count < max_for_this_host) break; } @@ -335,6 +352,7 @@ if ((max_for_this_host > 0) && log_write(L_connection_reject, LOG_MAIN, "Connection from %s refused: too many connections " "from that IP address", whofrom->s); + search_tidyup(); goto ERROR_RETURN; } } @@ -453,6 +471,7 @@ if (pid == 0) signal(SIGCHLD, SIG_IGN); #endif signal(SIGTERM, SIG_DFL); + signal(SIGINT, SIG_DFL); /* Attempt to get an id from the sending machine via the RFC 1413 protocol. We do this in the sub-process in order not to hold up the @@ -536,7 +555,7 @@ if (pid == 0) } if (message_id[0] == 0) continue; /* No message was accepted */ } - else + else /* bad smtp_setup_msg() */ { if (smtp_out) { @@ -656,15 +675,15 @@ if (pid == 0) { pid_t dpid; - /* Before forking, ensure that the C output buffer is flushed. Otherwise - anything that it in it will get duplicated, leading to duplicate copies - of the pending output. */ - - mac_smtp_fflush(); + /* We used to flush smtp_out before forking so that buffered data was not + duplicated, but now we want to pipeline the responses for data and quit. + Instead, hard-close the fd underlying smtp_out right after fork to discard + the data buffer. */ if ((dpid = exim_fork(US"daemon-accept-delivery")) == 0) { (void)fclose(smtp_in); + (void)close(fileno(smtp_out)); (void)fclose(smtp_out); /* Don't ever molest the parent's SSL connection, but do clean up @@ -679,6 +698,7 @@ if (pid == 0) signal(SIGHUP, SIG_DFL); signal(SIGCHLD, SIG_DFL); signal(SIGTERM, SIG_DFL); + signal(SIGINT, SIG_DFL); if (geteuid() != root_uid && !deliver_drop_privilege) { @@ -912,7 +932,6 @@ while ((pid = waitpid(-1, &status, WNOHANG)) > 0) } - static void set_pid_file_path(void) { @@ -921,38 +940,150 @@ if (override_pid_file_path) if (!*pid_file_path) pid_file_path = string_sprintf("%s/exim-daemon.pid", spool_directory); + +if (pid_file_path[0] != '/') + log_write(0, LOG_PANIC_DIE, "pid file path %s must be absolute\n", pid_file_path); } -/* Remove the daemon's pidfile. Note: runs with root privilege, -as a direct child of the daemon. Does not return. */ +enum pid_op { PID_WRITE, PID_CHECK, PID_DELETE }; -void -delete_pid_file(void) +/* Do various pid file operations as safe as possible. Ideally we'd just +drop the privileges for creation of the pid file and not care at all about removal of +the file. FIXME. +Returns: true on success, false + errno==EACCES otherwise +*/ +static BOOL +operate_on_pid_file(const enum pid_op operation, const pid_t pid) { -uschar * daemon_pid = string_sprintf("%d\n", (int)getppid()); -FILE * f; +char pid_line[sizeof(int) * 3 + 2]; +const int pid_len = snprintf(pid_line, sizeof(pid_line), "%d\n", (int)pid); +BOOL lines_match = FALSE; + +char * path = NULL; +char * base = NULL; +char * dir = NULL; + +const int dir_flags = O_RDONLY | O_NONBLOCK; +const int base_flags = O_NOFOLLOW | O_NONBLOCK; +const mode_t base_mode = 0644; +struct stat sb; + +int cwd_fd = -1; +int dir_fd = -1; +int base_fd = -1; + +BOOL success = FALSE; +errno = EACCES; set_pid_file_path(); -if ((f = Ufopen(pid_file_path, "rb"))) +if (!f.running_in_test_harness && real_uid != root_uid && real_uid != exim_uid) goto cleanup; +if (pid_len < 2 || pid_len >= (int)sizeof(pid_line)) goto cleanup; + +path = CS string_copy(pid_file_path); +if ((base = Ustrrchr(path, '/')) == NULL) /* should not happen, but who knows */ + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "pid file path \"%s\" does not contain a '/'", pid_file_path); + +dir = (base != path) ? path : "/"; +*base++ = '\0'; + +if (!dir || !*dir || *dir != '/') goto cleanup; +if (!base || !*base || strchr(base, '/') != NULL) goto cleanup; + +cwd_fd = open(".", dir_flags); +if (cwd_fd < 0 || fstat(cwd_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup; +dir_fd = open(dir, dir_flags); +if (dir_fd < 0 || fstat(dir_fd, &sb) != 0 || !S_ISDIR(sb.st_mode)) goto cleanup; + +/* emulate openat */ +if (fchdir(dir_fd) != 0) goto cleanup; +base_fd = open(base, O_RDONLY | base_flags); +if (fchdir(cwd_fd) != 0) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno)); + +if (base_fd >= 0) + { + char line[sizeof(pid_line)]; + ssize_t len = -1; + + if (fstat(base_fd, &sb) != 0 || !S_ISREG(sb.st_mode)) goto cleanup; + if ((sb.st_mode & 07777) != base_mode || sb.st_nlink != 1) goto cleanup; + if (sb.st_size < 2 || sb.st_size >= (off_t)sizeof(line)) goto cleanup; + + len = read(base_fd, line, sizeof(line)); + if (len != (ssize_t)sb.st_size) goto cleanup; + line[len] = '\0'; + + if (strspn(line, "0123456789") != (size_t)len-1) goto cleanup; + if (line[len-1] != '\n') goto cleanup; + lines_match = (len == pid_len && strcmp(line, pid_line) == 0); + } + +if (operation == PID_WRITE) { - if ( fgets(CS big_buffer, big_buffer_size, f) - && Ustrcmp(daemon_pid, big_buffer) == 0 - ) - if (Uunlink(pid_file_path) == 0) + if (!lines_match) + { + if (base_fd >= 0) { - DEBUG(D_any) - debug_printf("%s unlink: %s\n", pid_file_path, strerror(errno)); - } - else - DEBUG(D_any) - debug_printf("unlinked %s\n", pid_file_path); - fclose(f); + int error = -1; + /* emulate unlinkat */ + if (fchdir(dir_fd) != 0) goto cleanup; + error = unlink(base); + if (fchdir(cwd_fd) != 0) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno)); + if (error) goto cleanup; + (void)close(base_fd); + base_fd = -1; + } + /* emulate openat */ + if (fchdir(dir_fd) != 0) goto cleanup; + base_fd = open(base, O_WRONLY | O_CREAT | O_EXCL | base_flags, base_mode); + if (fchdir(cwd_fd) != 0) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno)); + if (base_fd < 0) goto cleanup; + if (fchmod(base_fd, base_mode) != 0) goto cleanup; + if (write(base_fd, pid_line, pid_len) != pid_len) goto cleanup; + DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path); + } } else - DEBUG(D_any) - debug_printf("%s\n", string_open_failed(errno, "pid file %s", - pid_file_path)); + { + if (!lines_match) goto cleanup; + if (operation == PID_DELETE) + { + int error = -1; + /* emulate unlinkat */ + if (fchdir(dir_fd) != 0) goto cleanup; + error = unlink(base); + if (fchdir(cwd_fd) != 0) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "can't return to previous working dir: %s", strerror(errno)); + if (error) goto cleanup; + } + } + +success = TRUE; +errno = 0; + +cleanup: +if (cwd_fd >= 0) (void)close(cwd_fd); +if (dir_fd >= 0) (void)close(dir_fd); +if (base_fd >= 0) (void)close(base_fd); +return success; +} + + +/* Remove the daemon's pidfile. Note: runs with root privilege, +as a direct child of the daemon. Does not return. */ + +void +delete_pid_file(void) +{ +const BOOL success = operate_on_pid_file(PID_DELETE, getppid()); + +DEBUG(D_any) + debug_printf("delete pid file %s %s: %s\n", pid_file_path, + success ? "success" : "failure", strerror(errno)); + exim_exit(EXIT_SUCCESS); } @@ -965,16 +1096,17 @@ daemon_die(void) { int pid; +DEBUG(D_any) debug_printf("SIGTERM/SIGINT seen\n"); +#if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT)) +tls_watch_invalidate(); +#endif + if (daemon_notifier_fd >= 0) { close(daemon_notifier_fd); daemon_notifier_fd = -1; #ifndef EXIM_HAVE_ABSTRACT_UNIX_SOCKETS - { - uschar * s = expand_string(notifier_socket); - DEBUG(D_any) debug_printf("unlinking notifier socket %s\n", s); - Uunlink(s); - } + unlink_notifier_socket(); #endif } @@ -1009,6 +1141,11 @@ const uschar * where; struct sockaddr_un sa_un = {.sun_family = AF_UNIX}; int len; +if (!notifier_socket || !*notifier_socket) + { + DEBUG(D_any) debug_printf("-oY used so not creating notifier socket\n"); + return; + } if (override_local_interfaces && !override_pid_file_path) { DEBUG(D_any) @@ -1035,7 +1172,7 @@ len = offsetof(struct sockaddr_un, sun_path) + 1 DEBUG(D_any) debug_printf(" @%s\n", sa_un.sun_path+1); #else /* filesystem-visible and persistent; will neeed removal */ len = offsetof(struct sockaddr_un, sun_path) - + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s", + + snprintf(sa_un.sun_path, sizeof(sa_un.sun_path), "%s", expand_string(notifier_socket)); DEBUG(D_any) debug_printf(" %s\n", sa_un.sun_path); #endif @@ -1137,14 +1274,14 @@ for (struct cmsghdr * cp = CMSG_FIRSTHDR(&msg); buf[sz] = 0; switch (buf[0]) { -#ifdef EXPERIMENTAL_QUEUE_RAMP +#ifndef DISABLE_QUEUE_RAMP case NOTIFY_MSG_QRUN: /* this should be a message_id */ DEBUG(D_queue_run) debug_printf("%s: qrunner trigger: %s\n", __FUNCTION__, buf+1); memcpy(queuerun_msgid, buf+1, MESSAGE_ID_LENGTH+1); return TRUE; -#endif /*EXPERIMENTAL_QUEUE_RAMP*/ +#endif case NOTIFY_QUEUE_SIZE_REQ: { @@ -1419,6 +1556,7 @@ if (f.daemon_listen && !f.inetd_wait_mode) list = tls_in.on_connect_ports; sep = 0; + /* the list isn't expanded so cannot be tainted. If it ever is we will trap here */ while ((s = string_nextinlist(&list, &sep, big_buffer, big_buffer_size))) if (!isdigit(*s)) { @@ -1812,23 +1950,14 @@ The variable daemon_write_pid is used to control this. */ if (f.running_in_test_harness || write_pid) { - FILE *f; - - set_pid_file_path(); - if ((f = modefopen(pid_file_path, "wb", 0644))) - { - (void)fprintf(f, "%d\n", (int)getpid()); - (void)fclose(f); - DEBUG(D_any) debug_printf("pid written to %s\n", pid_file_path); - } - else - DEBUG(D_any) - debug_printf("%s\n", string_open_failed(errno, "pid file %s", - pid_file_path)); + const enum pid_op operation = (f.running_in_test_harness + || real_uid == root_uid + || (real_uid == exim_uid && !override_pid_file_path)) ? PID_WRITE : PID_CHECK; + if (!operate_on_pid_file(operation, getpid())) + DEBUG(D_any) debug_printf("%s pid file %s: %s\n", (operation == PID_WRITE) ? "write" : "check", pid_file_path, strerror(errno)); } /* Set up the handler for SIGHUP, which causes a restart of the daemon. */ - sighup_seen = FALSE; signal(SIGHUP, sighup_handler); @@ -1865,6 +1994,7 @@ os_non_restarting_signal(SIGCHLD, main_sigchld_handler); sigterm_seen = FALSE; os_non_restarting_signal(SIGTERM, main_sigterm_handler); +os_non_restarting_signal(SIGINT, main_sigterm_handler); /* If we are to run the queue periodically, pretend the alarm has just gone off. This will cause the first queue-runner to get kicked off straight away. */ @@ -2037,6 +2167,9 @@ malware_init(); #ifdef SUPPORT_SPF spf_init(); #endif +#ifndef DISABLE_TLS +tls_daemon_init(); +#endif /* Close the log so it can be renamed and moved. In the few cases below where this long-running process writes to the log (always exceptional conditions), it @@ -2119,7 +2252,7 @@ for (;;) else { DEBUG(D_any) debug_printf("%s received\n", -#ifdef EXPERIMENTAL_QUEUE_RAMP +#ifndef DISABLE_QUEUE_RAMP *queuerun_msgid ? "qrun notification" : #endif "SIGALRM"); @@ -2149,6 +2282,7 @@ for (;;) signal(SIGHUP, SIG_DFL); signal(SIGCHLD, SIG_DFL); signal(SIGTERM, SIG_DFL); + signal(SIGINT, SIG_DFL); /* Re-exec if privilege has been given up, unless deliver_drop_ privilege is set. Reset SIGALRM before exec(). */ @@ -2164,7 +2298,7 @@ for (;;) *p++ = '-'; *p++ = 'q'; if ( f.queue_2stage -#ifdef EXPERIMENTAL_QUEUE_RAMP +#ifndef DISABLE_QUEUE_RAMP && !*queuerun_msgid #endif ) *p++ = 'q'; @@ -2176,7 +2310,7 @@ for (;;) extra[0] = *queue_name ? string_sprintf("%sG%s", opt, queue_name) : opt; -#ifdef EXPERIMENTAL_QUEUE_RAMP +#ifndef DISABLE_QUEUE_RAMP if (*queuerun_msgid) { log_write(0, LOG_MAIN, "notify triggered queue run"); @@ -2211,7 +2345,7 @@ for (;;) /* No need to re-exec; SIGALRM remains set to the default handler */ -#ifdef EXPERIMENTAL_QUEUE_RAMP +#ifndef DISABLE_QUEUE_RAMP if (*queuerun_msgid) { log_write(0, LOG_MAIN, "notify triggered queue run"); @@ -2247,7 +2381,7 @@ for (;;) /* Reset the alarm clock */ sigalrm_seen = FALSE; -#ifdef EXPERIMENTAL_QUEUE_RAMP +#ifndef DISABLE_QUEUE_RAMP if (*queuerun_msgid) *queuerun_msgid = 0; else @@ -2269,14 +2403,24 @@ for (;;) if (f.daemon_listen) { - int lcount, select_errno; + int lcount; int max_socket = 0; BOOL select_failed = FALSE; fd_set select_listen; FD_ZERO(&select_listen); +#ifndef DISABLE_TLS + if (tls_watch_fd >= 0) + { + FD_SET(tls_watch_fd, &select_listen); + if (tls_watch_fd > max_socket) max_socket = tls_watch_fd; + } +#endif if (daemon_notifier_fd >= 0) + { FD_SET(daemon_notifier_fd, &select_listen); + if (daemon_notifier_fd > max_socket) max_socket = daemon_notifier_fd; + } for (int sk = 0; sk < listen_socket_count; sk++) { FD_SET(listen_sockets[sk], &select_listen); @@ -2314,14 +2458,16 @@ for (;;) old one had just finished. Preserve the errno from any select() failure for the use of the common select/accept error processing below. */ - select_errno = errno; - handle_ending_processes(); - errno = select_errno; + { + int select_errno = errno; + handle_ending_processes(); #ifndef DISABLE_TLS - /* Create or rotate any required keys */ - tls_daemon_init(); + /* Create or rotate any required keys; handle (delayed) filewatch event */ + tls_daemon_tick(); #endif + errno = select_errno; + } /* Loop for all the sockets that are currently ready to go. If select actually failed, we have set the count to 1 and select_failed=TRUE, so as @@ -2333,6 +2479,15 @@ for (;;) if (!select_failed) { +#if !defined(DISABLE_TLS) && (defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT)) + if (tls_watch_fd >= 0 && FD_ISSET(tls_watch_fd, &select_listen)) + { + FD_CLR(tls_watch_fd, &select_listen); + tls_watch_trigger_time = time(NULL); /* Set up delayed event */ + tls_watch_discard_event(tls_watch_fd); + break; /* to top of daemon loop */ + } +#endif if ( daemon_notifier_fd >= 0 && FD_ISSET(daemon_notifier_fd, &select_listen)) { @@ -2368,45 +2523,43 @@ for (;;) accept_retry_errno = errno; accept_retry_select_failed = select_failed; } - else - { - if (errno != accept_retry_errno || - select_failed != accept_retry_select_failed || - accept_retry_count >= 50) + else if ( errno != accept_retry_errno + || select_failed != accept_retry_select_failed + || accept_retry_count >= 50) { - log_write(0, LOG_MAIN | ((accept_retry_count >= 50)? LOG_PANIC : 0), + log_write(0, LOG_MAIN | (accept_retry_count >= 50 ? LOG_PANIC : 0), "%d %s() failure%s: %s", accept_retry_count, - accept_retry_select_failed? "select" : "accept", - (accept_retry_count == 1)? "" : "s", + accept_retry_select_failed ? "select" : "accept", + accept_retry_count == 1 ? "" : "s", strerror(accept_retry_errno)); log_close_all(); accept_retry_count = 0; accept_retry_errno = errno; accept_retry_select_failed = select_failed; } - } accept_retry_count++; } - - else - { - if (accept_retry_count > 0) - { - log_write(0, LOG_MAIN, "%d %s() failure%s: %s", - accept_retry_count, - accept_retry_select_failed? "select" : "accept", - (accept_retry_count == 1)? "" : "s", - strerror(accept_retry_errno)); - log_close_all(); - accept_retry_count = 0; - } - } + else if (accept_retry_count > 0) + { + log_write(0, LOG_MAIN, "%d %s() failure%s: %s", + accept_retry_count, + accept_retry_select_failed ? "select" : "accept", + accept_retry_count == 1 ? "" : "s", + strerror(accept_retry_errno)); + log_close_all(); + accept_retry_count = 0; + } /* If select/accept succeeded, deal with the connection. */ if (accept_socket >= 0) { +#ifdef TCP_QUICKACK /* Avoid pure-ACKs while in tls protocol pingpong phase */ + /* Unfortunately we cannot be certain to do this before a TLS-on-connect + Client Hello arrives and is acked. We do it as early as possible. */ + (void) setsockopt(accept_socket, IPPROTO_TCP, TCP_QUICKACK, US &off, sizeof(off)); +#endif if (inetd_wait_timeout) last_connection_time = time(NULL); handle_smtp_call(listen_sockets, listen_socket_count, accept_socket,