* Exim - an Internet mail transport agent *
*************************************************/
+/* Copyright (c) The Exim Maintainers 2020 - 2022 */
/* Copyright (c) University of Cambridge 1995 - 2018 */
-/* Copyright (c) The Exim Maintainers 2020 */
/* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
/* This module provides TLS (aka SSL) support for Exim. The code for OpenSSL is
based on a patch that was originally contributed by Steve Haslam. It was
static void tls_per_lib_daemon_init(void);
static void tls_per_lib_daemon_tick(void);
-static void tls_server_creds_init(void);
+static unsigned tls_server_creds_init(void);
static void tls_server_creds_invalidate(void);
static void tls_client_creds_init(transport_instance *, BOOL);
static void tls_client_creds_invalidate(transport_instance *);
+static void tls_daemon_creds_reload(void);
+static BOOL opt_set_and_noexpand(const uschar *);
+static BOOL opt_unset_or_noexpand(const uschar *);
static BOOL ssl_xfer_error = FALSE;
#endif
+#ifdef EXIM_HAVE_KEVENT
+# define KEV_SIZE 16 /* Eight file,dir pairs */
+static struct kevent kev[KEV_SIZE];
+static int kev_used = 0;
+#endif
+
+static unsigned tls_creds_expire = 0;
/*************************************************
* Expand string; give error on failure *
*/
static BOOL
-expand_check(const uschar *s, const uschar *name, uschar **result, uschar ** errstr)
+expand_check(const uschar * s, const uschar * name,
+ uschar ** result, uschar ** errstr)
{
if (!s)
*result = NULL;
}
-#ifdef EXIM_HAVE_INOTIFY
+#if defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT)
/* Add the directory for a filename to the inotify handle, creating that if
needed. This is enough to see changes to files in that dir.
Return boolean success.
The string "system,cache" is recognised and explicitly accepted without
setting a watch. This permits the system CA bundle to be cached even though
we have no way to tell when it gets modified by an update.
-
-We *might* try to run "openssl version -d" and set watches on the dir
-indicated in its output, plus the "certs" subdir of it (following
-synlimks for both). But this is undocumented even for OpenSSL, and
-who knows what GnuTLS might be doing.
+The call chain for OpenSSL uses a (undocumented) call into the library
+to discover the actual file. We don't know what GnuTLS uses.
A full set of caching including the CAs takes 35ms output off of the
server tls_init() (GnuTLS, Fedora 32, 2018-class x86_64 laptop hardware).
*/
static BOOL
tls_set_one_watch(const uschar * filename)
+# ifdef EXIM_HAVE_INOTIFY
{
+uschar buf[PATH_MAX];
+ssize_t len;
uschar * s;
if (Ustrcmp(filename, "system,cache") == 0) return TRUE;
-
if (!(s = Ustrrchr(filename, '/'))) return FALSE;
-s = string_copyn(filename, s - filename);
+
+for (unsigned loop = 20;
+ (len = readlink(CCS filename, CS buf, sizeof(buf))) >= 0; )
+ { /* a symlink */
+ if (--loop == 0) { errno = ELOOP; return FALSE; }
+ filename = buf[0] == '/'
+ ? string_copyn(buf, (unsigned)len) /* mem released by tls_set_watch */
+ : string_sprintf("%.*s/%.*s", (int)(s - filename), filename, (int)len, buf);
+ s = Ustrrchr(filename, '/');
+ }
+if (errno != EINVAL)
+ return FALSE; /* other error */
+
+/* not a symlink */
+s = string_copyn(filename, s - filename); /* mem released by tls_set_watch */
+
DEBUG(D_tls) debug_printf("watch dir '%s'\n", s);
if (inotify_add_watch(tls_watch_fd, CCS s,
IN_ONESHOT | IN_CLOSE_WRITE | IN_DELETE | IN_DELETE_SELF
| IN_MOVED_FROM | IN_MOVED_TO | IN_MOVE_SELF) >= 0)
return TRUE;
-DEBUG(D_tls) debug_printf("add_watch: %s\n", strerror(errno));
+DEBUG(D_tls) debug_printf("notify_add_watch: %s\n", strerror(errno));
return FALSE;
}
+# endif
+# ifdef EXIM_HAVE_KEVENT
+{
+uschar * s, * t;
+int fd1, fd2, i, j, cnt = 0;
+struct stat sb;
+#ifdef OpenBSD
+struct kevent k_dummy;
+struct timespec ts = {0};
+#endif
+
+errno = 0;
+if (Ustrcmp(filename, "system,cache") == 0) return TRUE;
+
+for (;;)
+ {
+ if (kev_used > KEV_SIZE-2) { s = US"out of kev space"; goto bad; }
+ if (!(s = Ustrrchr(filename, '/'))) return FALSE;
+ s = string_copyn(filename, s - filename); /* mem released by tls_set_watch */
+
+ /* The dir open will fail if there is a symlink on the path. Fine; it's too
+ much effort to handle all possible cases; just refuse the preload. */
+
+ if ((fd2 = open(CCS s, O_RDONLY | O_NOFOLLOW)) < 0) { s = US"open dir"; goto bad; }
+
+ if ((lstat(CCS filename, &sb)) < 0) { s = US"lstat"; goto bad; }
+ if (!S_ISLNK(sb.st_mode))
+ {
+ if ((fd1 = open(CCS filename, O_RDONLY | O_NOFOLLOW)) < 0)
+ { s = US"open file"; goto bad; }
+ DEBUG(D_tls) debug_printf("watch file '%s':\t%d\n", filename, fd1);
+ EV_SET(&kev[kev_used++],
+ (uintptr_t)fd1,
+ EVFILT_VNODE,
+ EV_ADD | EV_ENABLE | EV_ONESHOT,
+ NOTE_DELETE | NOTE_WRITE | NOTE_EXTEND
+ | NOTE_ATTRIB | NOTE_RENAME | NOTE_REVOKE,
+ 0,
+ NULL);
+ cnt++;
+ }
+ DEBUG(D_tls) debug_printf("watch dir '%s':\t%d\n", s, fd2);
+ EV_SET(&kev[kev_used++],
+ (uintptr_t)fd2,
+ EVFILT_VNODE,
+ EV_ADD | EV_ENABLE | EV_ONESHOT,
+ NOTE_DELETE | NOTE_WRITE | NOTE_EXTEND
+ | NOTE_ATTRIB | NOTE_RENAME | NOTE_REVOKE,
+ 0,
+ NULL);
+ cnt++;
+
+ if (!(S_ISLNK(sb.st_mode))) break;
+
+ t = store_get(1024, GET_UNTAINTED);
+ Ustrncpy(t, s, 1022);
+ j = Ustrlen(s);
+ t[j++] = '/';
+ if ((i = readlink(CCS filename, (void *)(t+j), 1023-j)) < 0) { s = US"readlink"; goto bad; }
+ filename = t;
+ *(t += i+j) = '\0';
+ store_release_above(t+1);
+ }
+
+#ifdef OpenBSD
+if (kevent(tls_watch_fd, &kev[kev_used-cnt], cnt, &k_dummy, 1, &ts) >= 0)
+ return TRUE;
+#else
+if (kevent(tls_watch_fd, &kev[kev_used-cnt], cnt, NULL, 0, NULL) >= 0)
+ return TRUE;
+#endif
+s = US"kevent";
+
+bad:
+DEBUG(D_tls)
+ if (errno)
+ debug_printf("%s: %s: %s\n", __FUNCTION__, s, strerror(errno));
+ else
+ debug_printf("%s: %s\n", __FUNCTION__, s);
+return FALSE;
+}
+# endif /*EXIM_HAVE_KEVENT*/
/* Create an inotify facility if needed.
rmark r;
BOOL rc = FALSE;
-if (tls_watch_fd < 0 && (tls_watch_fd = inotify_init1(O_CLOEXEC)) < 0)
- {
- DEBUG(D_tls) debug_printf("inotify_init: %s\n", strerror(errno));
- return FALSE;
- }
-
if (!filename || !*filename) return TRUE;
+if (Ustrncmp(filename, "system", 6) == 0) return TRUE;
+
+DEBUG(D_tls) debug_printf("tls_set_watch: '%s'\n", filename);
+
+if ( tls_watch_fd < 0
+# ifdef EXIM_HAVE_INOTIFY
+ && (tls_watch_fd = inotify_init1(O_CLOEXEC)) < 0
+# endif
+# ifdef EXIM_HAVE_KEVENT
+ && (tls_watch_fd = kqueue()) < 0
+# endif
+ )
+ {
+ DEBUG(D_tls) debug_printf("inotify_init: %s\n", strerror(errno));
+ return FALSE;
+ }
r = store_mark();
rc = tls_set_one_watch(filename);
store_reset(r);
+if (!rc) DEBUG(D_tls) debug_printf("tls_set_watch() fail on '%s': %s\n", filename, strerror(errno));
return rc;
}
+void
+tls_watch_discard_event(int fd)
+{
+#ifdef EXIM_HAVE_INOTIFY
+(void) read(fd, big_buffer, big_buffer_size);
+#endif
+#ifdef EXIM_HAVE_KEVENT
+struct kevent kev;
+struct timespec t = {0};
+(void) kevent(fd, NULL, 0, &kev, 1, &t);
+#endif
+}
+#endif /*EXIM_HAVE_INOTIFY*/
+
+
void
tls_client_creds_reload(BOOL watch)
{
}
}
-static void
-tls_daemon_creds_reload(void)
-{
-tls_server_creds_invalidate();
-tls_server_creds_init();
-tls_client_creds_reload(TRUE);
-}
+void
+tls_watch_invalidate(void)
+{
+if (tls_watch_fd < 0) return;
+#ifdef EXIM_HAVE_KEVENT
+/* Close the files we had open for kevent */
+for (int i = 0; i < kev_used; i++)
+ {
+ DEBUG(D_tls) debug_printf("closing watch fd: %d\n", (int) kev[i].ident);
+ (void) close((int) kev[i].ident);
+ kev[i].ident = (uintptr_t)-1;
+ }
+kev_used = 0;
+#endif
-/* Called, after a delay for multiple file ops to get done, from
-the daemon when any of the watches added (above) fire.
+close(tls_watch_fd);
+tls_watch_fd = -1;
+}
-Dump the set of watches and arrange to reload cached creds (which
-will set up new watches). */
static void
-tls_watch_triggered(void)
+tls_daemon_creds_reload(void)
{
-DEBUG(D_tls) debug_printf("watch triggered\n");
-close(tls_watch_fd);
-tls_watch_fd = -1;
+unsigned lifetime;
+
+#ifdef EXIM_HAVE_KEVENT
+tls_watch_invalidate();
+#endif
-tls_daemon_creds_reload();
+tls_server_creds_invalidate();
+
+/* _expire is for a time-limited selfsign server cert */
+tls_creds_expire = (lifetime = tls_server_creds_init())
+ ? time(NULL) + lifetime : 0;
+
+tls_client_creds_reload(TRUE);
}
opt_unset_or_noexpand(const uschar * opt)
{ return !opt || Ustrchr(opt, '$') == NULL; }
-#endif /* EXIM_HAVE_INOTIFY */
-/* Called every time round the daemon loop */
+/* Called every time round the daemon loop.
-void
+If we reloaded fd-watcher, return the old watch fd
+having modified the global for the new one. Otherwise
+return -1.
+*/
+
+int
tls_daemon_tick(void)
{
+int old_watch_fd = tls_watch_fd;
+
tls_per_lib_daemon_tick();
-#ifdef EXIM_HAVE_INOTIFY
-if (tls_watch_trigger_time && time(NULL) >= tls_watch_trigger_time + 5)
+#if defined(EXIM_HAVE_INOTIFY) || defined(EXIM_HAVE_KEVENT)
+if (tls_creds_expire && time(NULL) >= tls_creds_expire)
+ {
+ /* The server cert is a selfsign, with limited lifetime. Dump it and
+ generate a new one. Reload the rest of the creds also as the machinery
+ is all there. */
+
+ DEBUG(D_tls) debug_printf("selfsign cert rotate\n");
+ tls_creds_expire = 0;
+ tls_daemon_creds_reload();
+ return old_watch_fd;
+ }
+else if (tls_watch_trigger_time && time(NULL) >= tls_watch_trigger_time + 5)
{
- tls_watch_trigger_time = 0;
- tls_watch_triggered();
+ /* Called, after a delay for multiple file ops to get done, from
+ the daemon when any of the watches added (above) fire.
+ Dump the set of watches and arrange to reload cached creds (which
+ will set up new watches). */
+
+ DEBUG(D_tls) debug_printf("watch triggered\n");
+ tls_watch_trigger_time = tls_creds_expire = 0;
+ tls_daemon_creds_reload();
+ return old_watch_fd;
}
#endif
+return -1;
}
/* Called once at daemon startup */
/*************************************************
* Many functions are package-specific *
*************************************************/
+/* Forward decl. */
+static void tls_client_resmption_key(tls_support *, smtp_connect_args *,
+ smtp_transport_options_block *);
+
#ifdef USE_GNUTLS
# include "tls-gnu.c"
int
tls_ungetc(int ch)
{
+if (ssl_xfer_buffer_lwm <= 0)
+ log_write(0, LOG_MAIN|LOG_PANIC_DIE, "buffer underflow in tls_ungetc");
+
ssl_xfer_buffer[--ssl_xfer_buffer_lwm] = ch;
return ch;
}
BOOL
tls_is_name_for_cert(const uschar * namelist, void * cert)
{
-uschar * altnames = tls_cert_subject_altname(cert, US"dns");
-uschar * subjdn;
-uschar * certname;
+uschar * altnames, * subjdn, * certname, * cmpname;
int cmp_sep = 0;
-uschar * cmpname;
if ((altnames = tls_cert_subject_altname(cert, US"dns")))
{
int alt_sep = '\n';
+ DEBUG(D_tls|D_lookup) debug_printf_indent("cert has SAN\n");
while ((cmpname = string_nextinlist(&namelist, &cmp_sep, NULL, 0)))
{
const uschar * an = altnames;
+ DEBUG(D_tls|D_lookup) debug_printf_indent(" %s in SANs?", cmpname);
while ((certname = string_nextinlist(&an, &alt_sep, NULL, 0)))
if (is_name_match(cmpname, certname))
+ {
+ DEBUG(D_tls|D_lookup) debug_printf_indent(" yes (matched %s)\n", certname);
return TRUE;
+ }
+ DEBUG(D_tls|D_lookup) debug_printf_indent(" no (end of SAN list)\n");
}
}
while ((cmpname = string_nextinlist(&namelist, &cmp_sep, NULL, 0)))
{
const uschar * sn = subjdn;
+ DEBUG(D_tls|D_lookup) debug_printf_indent(" %s in SN?", cmpname);
while ((certname = string_nextinlist(&sn, &sn_sep, NULL, 0)))
if ( *certname++ == 'C'
&& *certname++ == 'N'
&& *certname++ == '='
&& is_name_match(cmpname, certname)
)
+ {
+ DEBUG(D_tls|D_lookup) debug_printf_indent(" yes (matched %s)\n", certname);
return TRUE;
+ }
+ DEBUG(D_tls|D_lookup) debug_printf_indent(" no (end of CN)\n");
}
}
return FALSE;
}
-
/* Environment cleanup: The GnuTLS library uses SSLKEYLOGFILE in the environment
and writes a file by that name. Our OpenSSL code does the same, using keying
info from the library API.
+static void
+tls_client_resmption_key(tls_support * tlsp, smtp_connect_args * conn_args,
+ smtp_transport_options_block * ob)
+{
+#ifndef DISABLE_TLS_RESUME
+hctx * h = &tlsp->resume_hctx;
+blob b;
+gstring * g;
+
+DEBUG(D_tls) if (conn_args->host_lbserver)
+ debug_printf("TLS: lbserver '%s'\n", conn_args->host_lbserver);
+
+# ifdef EXIM_HAVE_SHA2
+exim_sha_init(h, HASH_SHA2_256);
+# else
+exim_sha_init(h, HASH_SHA1);
+# endif
+exim_sha_update_string(h, conn_args->host_lbserver);
+# ifdef SUPPORT_DANE
+if (conn_args->dane)
+ exim_sha_update(h, CUS &conn_args->tlsa_dnsa, sizeof(dns_answer));
+# endif
+exim_sha_update_string(h, conn_args->host->address);
+exim_sha_update(h, CUS &conn_args->host->port, sizeof(conn_args->host->port));
+exim_sha_update_string(h, conn_args->sending_ip_address);
+exim_sha_update_string(h, openssl_options);
+exim_sha_update_string(h, ob->tls_require_ciphers);
+exim_sha_update_string(h, tlsp->sni);
+# ifdef EXIM_HAVE_ALPN
+exim_sha_update_string(h, ob->tls_alpn);
+# endif
+exim_sha_finish(h, &b);
+for (g = string_get(b.len*2+1); b.len-- > 0; )
+ g = string_fmt_append(g, "%02x", *b.data++);
+tlsp->resume_index = string_from_gstring(g);
+DEBUG(D_tls) debug_printf("TLS: resume session index %s\n", tlsp->resume_index);
+#endif
+}
+
+
+
+/* Start TLS as a client for an ajunct connection, eg. readsocket
+Return boolean success.
+*/
+
+BOOL
+tls_client_adjunct_start(host_item * host, client_conn_ctx * cctx,
+ const uschar * sni, uschar ** errmsg)
+{
+union sockaddr_46 interface_sock;
+EXIM_SOCKLEN_T size = sizeof(interface_sock);
+smtp_connect_args conn_args = {.host = host };
+tls_support tls_dummy = { .sni = NULL };
+uschar * errstr;
+
+if (getsockname(cctx->sock, (struct sockaddr *) &interface_sock, &size) == 0)
+ conn_args.sending_ip_address = host_ntoa(-1, &interface_sock, NULL, NULL);
+else
+ {
+ *errmsg = string_sprintf("getsockname failed: %s", strerror(errno));
+ return FALSE;
+ }
+
+/* To handle SNI we need to emulate more of a real transport because the
+base tls code assumes that is where the SNI string lives. */
+
+if (*sni)
+ {
+ transport_instance * tb;
+ smtp_transport_options_block * ob;
+
+ conn_args.tblock = tb = store_get(sizeof(*tb), GET_UNTAINTED);
+ memset(tb, 0, sizeof(*tb));
+
+ tb->options_block = ob = store_get(sizeof(*ob), GET_UNTAINTED);
+ memcpy(ob, &smtp_transport_option_defaults, sizeof(*ob));
+
+ ob->tls_sni = sni;
+ }
+
+if (!tls_client_start(cctx, &conn_args, NULL, &tls_dummy, &errstr))
+ {
+ *errmsg = string_sprintf("TLS connect failed: %s", errstr);
+ return FALSE;
+ }
+return TRUE;
+}
+
+
+
#endif /*!DISABLE_TLS*/
#endif /*!MACRO_PREDEF*/
git://git.exim.org / exim.git / blobdiff