From ed58c2eff21612037bbcc633f4b3a8e708f522a0 Mon Sep 17 00:00:00 2001
From: Frederik Vermeulen <qmail-tls@inoa.net>
Date: Mon, 18 May 2020 22:10:29 +0200
Subject: [PATCH] http://inoa.net/qmail-tls/

This patch implements RFC 3207 in qmail.
This means you can get SSL or TLS encrypted and
authenticated SMTP between the MTAs and from MUA to MTA.
The code is considered experimental (but has worked for
many since its first release on 1999-03-21).

Usage: - install OpenSSL-1.1.0 http://www.openssl.org/ or later
         (any version since 0.9.8 is presumed to work)
       - apply patch to netqmail-1.06 http://www.usenix.org.uk/mirrors/qmail/netqmail
         The patches to qmail-remote.c and qmail-smtpd.c can be applied
         separately.
       - provide a server certificate in /var/qmail/control/servercert.pem.
         "make cert" makes a self-signed certificate.
         "make cert-req" makes a certificate request.
         Note: you can add the CA certificate and intermediate
         certs to the end of servercert.pem.
       - replace qmail-smtpd and/or qmail-remote binary
       - verify operation (header information should show
         something like
         "Received [..] with (DHE-RSA-AES256-SHA encrypted) SMTP;")

Optional: - when DEBUG is defined, some extra TLS info will be logged
          - qmail-remote will authenticate with the certificate in
            /var/qmail/control/clientcert.pem. By preference this is
            the same as servercert.pem, where nsCertType should be
            == server,client or be a generic certificate (no usage specified).
          - when a 2048 bit RSA key is provided in /var/qmail/control/rsa2048.pem,
            this key will be used instead of (slow) on-the-fly generation by
            qmail-smtpd. Idem for 2048 DH param in control/dh2048.pem.
            `make tmprsadh` does this.
            Periodical replacement can be done by crontab:
            01 01 * * * /var/qmail/bin/update_tmprsadh > /dev/null 2>&1
          - server authentication:
            qmail-remote requires authentication from servers for which
            /var/qmail/control/tlshosts/host.dom.ain.pem exists.
            The .pem file contains the validating CA certificates.
            One of the dNSName or the CommonName attributes have to match.
            WARNING: this option may cause mail to be delayed, bounced,
            doublebounced, and lost.
            If /var/qmail/control/tlshosts/exhaustivelist is present,
            the lists of hosts in /var/qmail/control/tlshosts is
            an exhaustive list of hosts TLS is tried on.
            If /var/qmail/control/notlshosts/host.dom.ain is present,
            no TLS is tried on this host.
          - client authentication:
            when relay rules would reject an incoming mail,
            qmail-smtpd can allow the mail based on a presented cert.
            Certs are verified against a CA list in
            /var/qmail/control/clientca.pem (eg. from
            http://curl.haxx.se/ca/cacert.pem)
            and the cert email-address has to match a line in
            /var/qmail/control/tlsclients. This email-address is logged
            in the headers. CRLs can be provided through
            /var/qmail/control/clientcrl.pem.
          - cipher selection:
            qmail-remote:
              openssl cipher string (`man ciphers`) read from
              /var/qmail/control/tlsclientciphers
            qmail-smtpd:
              openssl cipher string read from TLSCIPHERS environment variable
              (can vary based on client IP address e.g.)
              or if that is not available /var/qmail/control/tlsserverciphers
          - smtps (deprecated SMTP over TLS via port 465):
            qmail-remote: when connecting to port 465
            qmail-smtpd: when SMTPS environment variable is not empty

Caveats: - do a `make clean` after patching
         - binaries dynamically linked with current openssl versions need
           recompilation when the shared openssl libs are upgraded.
         - this patch could conflict with other patches (notably those
           replacing \n with \r\n, which is a bad idea on encrypted links).
         - needs working /dev/urandom (or EGD for openssl versions >0.9.7)
           for seeding random number generator.
         - packagers should make sure that installing without a valid
           servercert is impossible
         - when applied in combination with AUTH patch, AUTH patch
           should be applied first and first part of this patch
           will fail. This error can be ignored. Packagers should
           cut the first 12 lines of this patch to make a happy
           patch
         - `make tmprsadh` is recommended (or should I say required),
           otherwise DH generation can be unpredictably slow
         - some need "-I/usr/kerberos/include" to be added in conf-cc

Copyright: GPL
           Links with OpenSSL
           Inspiration and code from examples in SSLeay (E. Young
           <eay@cryptsoft.com> and T. Hudson <tjh@cryptsoft.com>),
           stunnel (M. Trojnara <mtrojnar@ddc.daewoo.com.pl>),
           Postfix/TLS (L. Jaenicke <Lutz.Jaenicke@aet.tu-cottbus.de>),
           modssl (R. Engelschall <rse@engelschall.com>),
           openssl examples of E. Rescorla <ekr@rtfm.com>.

Bug reports: mailto:<qmail-tls akrul inoa.net>
---
 Makefile           |  40 ++++-
 Makefile-cert.mk   |  21 +++
 TARGETS            |   4 +
 conf-cc            |   2 +-
 dns.c              |  17 ++-
 hier.c             |   3 +
 ipalloc.h          |   8 +
 qmail-control.9    |   9 ++
 qmail-remote.8     |  43 ++++++
 qmail-remote.c     | 366 +++++++++++++++++++++++++++++++++++++++++++++
 qmail-smtpd.8      |  61 ++++++++
 qmail-smtpd.c      | 324 ++++++++++++++++++++++++++++++++++++++-
 ssl_timeoutio.c    | 126 ++++++++++++++++
 ssl_timeoutio.h    |  21 +++
 tls.c              |  27 ++++
 tls.h              |  16 ++
 update_tmprsadh.sh |  19 +++
 17 files changed, 1100 insertions(+), 7 deletions(-)
 create mode 100644 Makefile-cert.mk
 create mode 100644 ssl_timeoutio.c
 create mode 100644 ssl_timeoutio.h
 create mode 100644 tls.c
 create mode 100644 tls.h
 create mode 100644 update_tmprsadh.sh

diff --git a/Makefile b/Makefile
index 563ab22..f72825e 100644
--- a/Makefile
+++ b/Makefile
@@ -802,7 +802,7 @@ dnsptr dnsip dnsfq hostname ipmeprint qreceipt qsmhook qbiff \
 forward preline condredirect bouncesaying except maildirmake \
 maildir2mbox maildirwatch qail elq pinq install instpackage instchown \
 instcheck home home+df proc proc+df binm1 binm1+df binm2 binm2+df \
-binm3 binm3+df
+binm3 binm3+df update_tmprsadh
 
 load: \
 make-load warn-auto.sh
@@ -1416,6 +1416,7 @@ ndelay.a case.a sig.a open.a lock.a seek.a getln.a stralloc.a alloc.a \
 substdio.a error.a str.a fs.a auto_qmail.o dns.lib socket.lib
 	./load qmail-remote control.o constmap.o timeoutread.o \
 	timeoutwrite.o timeoutconn.o tcpto.o now.o dns.o ip.o \
+	tls.o ssl_timeoutio.o -L/usr/local/ssl/lib -lssl -lcrypto \
 	ipalloc.o ipme.o quote.o ndelay.a case.a sig.a open.a \
 	lock.a seek.a getln.a stralloc.a alloc.a substdio.a error.a \
 	str.a fs.a auto_qmail.o  `cat dns.lib` `cat socket.lib`
@@ -1515,6 +1516,7 @@ open.a sig.a case.a env.a stralloc.a alloc.a substdio.a error.a str.a \
 fs.a auto_qmail.o socket.lib
 	./load qmail-smtpd rcpthosts.o commands.o timeoutread.o \
 	timeoutwrite.o ip.o ipme.o ipalloc.o control.o constmap.o \
+	tls.o ssl_timeoutio.o ndelay.a -L/usr/local/ssl/lib -lssl -lcrypto \
 	received.o date822fmt.o now.o qmail.o cdb.a fd.a wait.a \
 	datetime.a getln.a open.a sig.a case.a env.a stralloc.a \
 	alloc.a substdio.a error.a str.a fs.a auto_qmail.o  `cat \
@@ -2003,6 +2005,19 @@ timeoutwrite.o: \
 compile timeoutwrite.c timeoutwrite.h select.h error.h readwrite.h
 	./compile timeoutwrite.c
 
+qmail-smtpd: tls.o ssl_timeoutio.o ndelay.a
+qmail-remote: tls.o ssl_timeoutio.o
+qmail-smtpd.o: tls.h ssl_timeoutio.h
+qmail-remote.o: tls.h ssl_timeoutio.h
+
+tls.o: \
+compile tls.c exit.h error.h
+	./compile tls.c
+
+ssl_timeoutio.o: \
+compile ssl_timeoutio.c ssl_timeoutio.h select.h error.h ndelay.h
+	./compile ssl_timeoutio.c
+
 token822.o: \
 compile token822.c stralloc.h gen_alloc.h alloc.h str.h token822.h \
 gen_alloc.h gen_allocdefs.h
@@ -2031,3 +2046,26 @@ compile wait_nohang.c haswaitp.h
 wait_pid.o: \
 compile wait_pid.c error.h haswaitp.h
 	./compile wait_pid.c
+
+cert cert-req: \
+Makefile-cert
+	@$(MAKE) -sf $< $@
+
+Makefile-cert: \
+conf-qmail conf-users conf-groups Makefile-cert.mk
+	@cat Makefile-cert.mk \
+	| sed s}QMAIL}"`head -1 conf-qmail`"}g \
+	> $@
+
+update_tmprsadh: \
+conf-qmail conf-users conf-groups update_tmprsadh.sh
+	@cat update_tmprsadh.sh\
+	| sed s}UGQMAILD}"`head -2 conf-users|tail -1`:`head -1 conf-groups`"}g \
+	| sed s}QMAIL}"`head -1 conf-qmail`"}g \
+	> $@
+	chmod 755 update_tmprsadh 
+
+tmprsadh: \
+update_tmprsadh
+	echo "Creating new temporary RSA and DH parameters"
+	./update_tmprsadh
diff --git a/Makefile-cert.mk b/Makefile-cert.mk
new file mode 100644
index 0000000..d869999
--- /dev/null
+++ b/Makefile-cert.mk
@@ -0,0 +1,21 @@
+cert-req: req.pem
+cert cert-req: QMAIL/control/clientcert.pem
+	@:
+
+QMAIL/control/clientcert.pem: QMAIL/control/servercert.pem
+	ln -s $< $@
+
+QMAIL/control/servercert.pem:
+	PATH=$$PATH:/usr/local/ssl/bin \
+		openssl req -new -x509 -nodes -days 366 -out $@ -keyout $@
+	chmod 640 $@
+	chown `head -2 conf-users | tail -1`:`head -1 conf-groups` $@
+
+req.pem:
+	PATH=$$PATH:/usr/local/ssl/bin openssl req \
+		-new -nodes -out $@ -keyout QMAIL/control/servercert.pem
+	chmod 640 QMAIL/control/servercert.pem
+	chown `head -2 conf-users | tail -1`:`head -1 conf-groups` QMAIL/control/servercert.pem
+	@echo
+	@echo "Send req.pem to your CA to obtain signed_req.pem, and do:"
+	@echo "cat signed_req.pem >> QMAIL/control/servercert.pem"
diff --git a/TARGETS b/TARGETS
index 825b310..92cbd09 100644
--- a/TARGETS
+++ b/TARGETS
@@ -185,6 +185,8 @@ control.o
 constmap.o
 timeoutread.o
 timeoutwrite.o
+tls.o
+ssl_timeoutio.o
 timeoutconn.o
 tcpto.o
 dns.o
@@ -333,6 +335,7 @@ binm2
 binm2+df
 binm3
 binm3+df
+Makefile-cert
 qmail-local.0
 qmail-lspawn.0
 qmail-getpw.8
@@ -397,3 +400,4 @@ forgeries.0
 setup
 qtmp.h
 qmail-send.service
+update_tmprsadh
diff --git a/conf-cc b/conf-cc
index e58fb9b..6f21fc6 100644
--- a/conf-cc
+++ b/conf-cc
@@ -1,3 +1,3 @@
-cc -O2
+cc -O2 -DTLS=20200107 -I/usr/local/ssl/include
 
 This will be used to compile .c files.
diff --git a/dns.c b/dns.c
index d90ba0f..f684c4a 100644
--- a/dns.c
+++ b/dns.c
@@ -263,12 +263,14 @@ int dns_ptr(stralloc *sa, struct ip_address *ipa)
 static int dns_ipplus(ipalloc *ia, stralloc *sa, int dpref)
 {
  int r;
- struct ip_mx ix;
+ struct ip_mx ix = {0};
 
  if (!stralloc_copy(&glue,sa)) return DNS_MEM;
  if (!stralloc_0(&glue)) return DNS_MEM;
  if (glue.s[0]) {
+#ifndef IX_FQDN
    ix.pref = 0;
+#endif
    if (!glue.s[ip_scan(glue.s,&ix.ip)] || !glue.s[ip_scanbracket(glue.s,&ix.ip)])
     {
      if (!ipalloc_append(ia,&ix)) return DNS_MEM;
@@ -287,9 +289,16 @@ static int dns_ipplus(ipalloc *ia, stralloc *sa, int dpref)
    ix.ip = ip;
    ix.pref = dpref;
    if (r == DNS_SOFT) return DNS_SOFT;
-   if (r == 1)
+   if (r == 1) {
+#ifdef IX_FQDN
+     ix.fqdn = glue.s;
+#endif
      if (!ipalloc_append(ia,&ix)) return DNS_MEM;
   }
+  }
+#ifdef IX_FQDN
+ glue.s = 0;
+#endif
  return 0;
 }
 
@@ -309,7 +318,7 @@ unsigned long random;
 {
  int r;
  struct mx { stralloc sa; unsigned short p; } *mx;
- struct ip_mx ix;
+ struct ip_mx ix = {0};
  int nummx;
  int i;
  int j;
@@ -321,7 +330,9 @@ unsigned long random;
  if (!stralloc_copy(&glue,sa)) return DNS_MEM;
  if (!stralloc_0(&glue)) return DNS_MEM;
  if (glue.s[0]) {
+#ifndef IX_FQDN
    ix.pref = 0;
+#endif
    if (!glue.s[ip_scan(glue.s,&ix.ip)] || !glue.s[ip_scanbracket(glue.s,&ix.ip)])
     {
      if (!ipalloc_append(ia,&ix)) return DNS_MEM;
diff --git a/hier.c b/hier.c
index d7de97a..8741a2c 100644
--- a/hier.c
+++ b/hier.c
@@ -143,6 +143,9 @@ void hier()
   c(auto_qmail,"bin","qail",auto_uido,auto_gidq,0755);
   c(auto_qmail,"bin","elq",auto_uido,auto_gidq,0755);
   c(auto_qmail,"bin","pinq",auto_uido,auto_gidq,0755);
+#ifdef TLS
+  c(auto_qmail,"bin","update_tmprsadh",auto_uido,auto_gidq,0755);
+#endif
 
   c(auto_qmail,"man/man5","addresses.5",auto_uido,auto_gidq,0644);
   c(auto_qmail,"man/cat5","addresses.0",auto_uido,auto_gidq,0644);
diff --git a/ipalloc.h b/ipalloc.h
index ad61475..bf9d060 100644
--- a/ipalloc.h
+++ b/ipalloc.h
@@ -3,7 +3,15 @@
 
 #include "ip.h"
 
+#ifdef TLS
+# define IX_FQDN 1
+#endif
+
+#ifdef IX_FQDN
+struct ip_mx { struct ip_address ip; int pref; char *fqdn; } ;
+#else
 struct ip_mx { struct ip_address ip; int pref; } ;
+#endif
 
 #include "gen_alloc.h"
 
diff --git a/qmail-control.9 b/qmail-control.9
index 503ce93..945f15f 100644
--- a/qmail-control.9
+++ b/qmail-control.9
@@ -43,11 +43,14 @@ control	default	used by
 .I badmailfrom	\fR(none)	\fRqmail-smtpd
 .I bouncefrom	\fRMAILER-DAEMON	\fRqmail-send
 .I bouncehost	\fIme	\fRqmail-send
+.I clientca.pem	\fR(none)	\fRqmail-smtpd
+.I clientcert.pem	\fR(none)	\fRqmail-remote
 .I concurrencylocal	\fR10	\fRqmail-send
 .I concurrencyremote	\fR20	\fRqmail-send
 .I defaultdomain	\fIme	\fRqmail-inject
 .I defaulthost	\fIme	\fRqmail-inject
 .I databytes	\fR0	\fRqmail-smtpd
+.I dh2048.pem	\fR(none)	\fRqmail-smtpd
 .I doublebouncehost	\fIme	\fRqmail-send
 .I doublebounceto	\fRpostmaster	\fRqmail-send
 .I envnoathost	\fIme	\fRqmail-send
@@ -61,11 +64,17 @@ control	default	used by
 .I qmqpservers	\fR(none)	\fRqmail-qmqpc
 .I queuelifetime	\fR604800	\fRqmail-send
 .I rcpthosts	\fR(none)	\fRqmail-smtpd
+.I rsa2048.pem	\fR(none)	\fRqmail-smtpd
+.I servercert.pem	\fR(none)	\fRqmail-smtpd
 .I smtpgreeting	\fIme	\fRqmail-smtpd
 .I smtproutes	\fR(none)	\fRqmail-remote
 .I timeoutconnect	\fR60	\fRqmail-remote
 .I timeoutremote	\fR1200	\fRqmail-remote
 .I timeoutsmtpd	\fR1200	\fRqmail-smtpd
+.I tlsclients	\fR(none)	\fRqmail-smtpd
+.I tlsclientciphers	\fR(none)	\fRqmail-remote
+.I tlshosts/FQDN.pem	\fR(none)	\fRqmail-remote
+.I tlsserverciphers	\fR(none)	\fRqmail-smtpd
 .I virtualdomains	\fR(none)	\fRqmail-send
 .fi
 .RE
diff --git a/qmail-remote.8 b/qmail-remote.8
index e38d169..a42f4f3 100644
--- a/qmail-remote.8
+++ b/qmail-remote.8
@@ -121,6 +121,10 @@ arguments.
 always exits zero.
 .SH "CONTROL FILES"
 .TP 5
+.I clientcert.pem
+SSL certificate that is used to authenticate with the remote server
+during a TLS session.
+.TP 5
 .I helohost
 Current host name,
 for use solely in saying hello to the remote SMTP server.
@@ -130,6 +134,16 @@ if that is supplied;
 otherwise
 .B qmail-remote
 refuses to run.
+
+.TP 5
+.I notlshosts/<FQDN>
+.B qmail-remote
+will not try TLS on servers for which this file exists
+.RB ( <FQDN>
+is the fully-qualified domain name of the server). 
+.IR (tlshosts/<FQDN>.pem 
+takes precedence over this file however).
+
 .TP 5
 .I smtproutes
 Artificial SMTP routes.
@@ -163,6 +177,8 @@ may be empty;
 this tells
 .B qmail-remote
 to look up MX records as usual.
+.I port 
+value of 465 (deprecated smtps port) causes TLS session to be started.
 .I smtproutes
 may include wildcards:
 
@@ -202,6 +218,33 @@ Number of seconds
 .B qmail-remote
 will wait for each response from the remote SMTP server.
 Default: 1200.
+
+.TP 5
+.I tlsclientciphers
+A set of OpenSSL client cipher strings. Multiple ciphers
+contained in a string should be separated by a colon.
+
+.TP 5
+.I tlshosts/<FQDN>.pem
+.B qmail-remote
+requires TLS authentication from servers for which this file exists
+.RB ( <FQDN>
+is the fully-qualified domain name of the server). One of the
+.I dNSName
+or the
+.I CommonName
+attributes have to match. The file contains the trusted CA certificates.
+
+.B WARNING:
+this option may cause mail to be delayed, bounced, doublebounced, or lost.
+
+.TP 5
+.I tlshosts/exhaustivelist
+if this file exists
+no TLS will be tried on hosts other than those for which a file
+.B tlshosts/<FQDN>.pem
+exists.
+
 .SH "SEE ALSO"
 addresses(5),
 envelopes(5),
diff --git a/qmail-remote.c b/qmail-remote.c
index 7d65473..c488b30 100644
--- a/qmail-remote.c
+++ b/qmail-remote.c
@@ -48,6 +48,17 @@ saa reciplist = {0};
 
 struct ip_address partner;
 
+#ifdef TLS
+# include <sys/stat.h>
+# include "tls.h"
+# include "ssl_timeoutio.h"
+# include <openssl/x509v3.h>
+# define EHLO 1
+
+int tls_init();
+const char *ssl_err_str = 0;
+#endif 
+
 void out(s) char *s; { if (substdio_puts(subfdoutsmall,s) == -1) _exit(0); }
 void zero() { if (substdio_put(subfdoutsmall,"\0",1) == -1) _exit(0); }
 void zerodie() { zero(); substdio_flush(subfdoutsmall); _exit(0); }
@@ -99,6 +110,9 @@ void dropped() {
   outhost();
   out(" but connection died. ");
   if (flagcritical) out("Possible duplicate! ");
+#ifdef TLS
+  if (ssl_err_str) { out((char *)ssl_err_str); out(" "); }
+#endif
   out("(#4.4.2)\n");
   zerodie();
 }
@@ -110,6 +124,12 @@ int timeout = 1200;
 int saferead(fd,buf,len) int fd; char *buf; int len;
 {
   int r;
+#ifdef TLS
+  if (ssl) {
+    r = ssl_timeoutread(timeout, smtpfd, smtpfd, ssl, buf, len);
+    if (r < 0) ssl_err_str = ssl_error_str();
+  } else
+#endif
   r = timeoutread(timeout,smtpfd,buf,len);
   if (r <= 0) dropped();
   return r;
@@ -117,6 +137,12 @@ int saferead(fd,buf,len) int fd; char *buf; int len;
 int safewrite(fd,buf,len) int fd; char *buf; int len;
 {
   int r;
+#ifdef TLS
+  if (ssl) {
+    r = ssl_timeoutwrite(timeout, smtpfd, smtpfd, ssl, buf, len);
+    if (r < 0) ssl_err_str = ssl_error_str();
+  } else
+#endif 
   r = timeoutwrite(timeout,smtpfd,buf,len);
   if (r <= 0) dropped();
   return r;
@@ -163,6 +189,65 @@ unsigned long smtpcode()
   return code;
 }
 
+#ifdef EHLO
+saa ehlokw = {0}; /* list of EHLO keywords and parameters */
+int maxehlokwlen = 0;
+
+unsigned long ehlo()
+{
+  stralloc *sa;
+  char *s, *e, *p;
+  unsigned long code;
+
+  if (ehlokw.len > maxehlokwlen) maxehlokwlen = ehlokw.len;
+  ehlokw.len = 0;
+
+# ifdef MXPS
+  if (type == 's') return 0;
+# endif
+
+  substdio_puts(&smtpto, "EHLO ");
+  substdio_put(&smtpto, helohost.s, helohost.len);
+  substdio_puts(&smtpto, "\r\n");
+  substdio_flush(&smtpto);
+
+  code = smtpcode();
+  if (code != 250) return code;
+
+  s = smtptext.s;
+  while (*s++ != '\n') ; /* skip the first line: contains the domain */
+
+  e = smtptext.s + smtptext.len - 6; /* 250-?\n */
+  while (s <= e)
+  {
+    int wasspace = 0;
+
+    if (!saa_readyplus(&ehlokw, 1)) temp_nomem();
+    sa = ehlokw.sa + ehlokw.len++;
+    if (ehlokw.len > maxehlokwlen) *sa = sauninit; else sa->len = 0;
+
+     /* smtptext is known to end in a '\n' */
+     for (p = (s += 4); ; ++p)
+       if (*p == '\n' || *p == ' ' || *p == '\t') {
+         if (!wasspace)
+           if (!stralloc_catb(sa, s, p - s) || !stralloc_0(sa)) temp_nomem();
+         if (*p == '\n') break;
+         wasspace = 1;
+       } else if (wasspace == 1) {
+         wasspace = 0;
+         s = p;
+       }
+    s = ++p;
+
+    /* keyword should consist of alpha-num and '-'
+     * broken AUTH might use '=' instead of space */
+    for (p = sa->s; *p; ++p) if (*p == '=') { *p = 0; break; }
+  }
+
+  return 250;
+}
+#endif
+
 void outsmtptext()
 {
   int i; 
@@ -179,6 +264,17 @@ void quit(prepend,append)
 char *prepend;
 char *append;
 {
+#ifdef TLS
+  /* shouldn't talk to the client unless in an appropriate state */
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+  OSSL_HANDSHAKE_STATE state = ssl ? SSL_get_state(ssl) : TLS_ST_BEFORE;
+  if (state & TLS_ST_OK || (!smtps && state & TLS_ST_BEFORE))
+  
+#else
+  int state = ssl ? ssl->state : SSL_ST_BEFORE;
+  if (state & SSL_ST_OK || (!smtps && state & SSL_ST_BEFORE))
+#endif
+#endif
   substdio_putsflush(&smtpto,"QUIT\r\n");
   /* waiting for remote side is just too ridiculous */
   out(prepend);
@@ -186,6 +282,30 @@ char *append;
   out(append);
   out(".\n");
   outsmtptext();
+
+#if defined(TLS) && defined(DEBUG)
+  if (ssl) {
+    X509 *peercert;
+
+    out("STARTTLS proto="); out(SSL_get_version(ssl));
+    out("; cipher="); out(SSL_get_cipher(ssl));
+
+    /* we want certificate details */
+    if (peercert = SSL_get_peer_certificate(ssl)) {
+      char *str;
+
+      str = X509_NAME_oneline(X509_get_subject_name(peercert), NULL, 0);
+      out("; subject="); out(str); OPENSSL_free(str);
+
+      str = X509_NAME_oneline(X509_get_issuer_name(peercert), NULL, 0);
+      out("; issuer="); out(str); OPENSSL_free(str);
+
+      X509_free(peercert);
+    }
+    out(";\n");
+  }
+#endif
+
   zerodie();
 }
 
@@ -214,6 +334,210 @@ void blast()
   substdio_flush(&smtpto);
 }
 
+#ifdef TLS
+char *partner_fqdn = 0;
+
+# define TLS_QUIT quit(ssl ? "; connected to " : "; connecting to ", "")
+void tls_quit(const char *s1, const char *s2)
+{
+  out((char *)s1); if (s2) { out(": "); out((char *)s2); } TLS_QUIT;
+}
+# define tls_quit_error(s) tls_quit(s, ssl_error())
+
+int match_partner(const char *s, int len)
+{
+  if (!case_diffb(partner_fqdn, len, s) && !partner_fqdn[len]) return 1;
+  /* we also match if the name is *.domainname */
+  if (*s == '*') {
+    const char *domain = partner_fqdn + str_chr(partner_fqdn, '.');
+    if (!case_diffb(domain, --len, ++s) && !domain[len]) return 1;
+  }
+  return 0;
+}
+
+/* don't want to fail handshake if certificate can't be verified */
+int verify_cb(int preverify_ok, X509_STORE_CTX *ctx) { return 1; }
+
+int tls_init()
+{
+  int i;
+  SSL *myssl;
+  SSL_CTX *ctx;
+  stralloc saciphers = {0};
+  const char *ciphers, *servercert = 0;
+
+  if (partner_fqdn) {
+    struct stat st;
+    stralloc tmp = {0};
+    if (!stralloc_copys(&tmp, "control/tlshosts/")
+      || !stralloc_catb(&tmp, partner_fqdn, str_len(partner_fqdn))
+      || !stralloc_catb(&tmp, ".pem", 5)) temp_nomem();
+    if (stat(tmp.s, &st) == 0) 
+      servercert = tmp.s;
+    else {
+      if (!stralloc_copys(&tmp, "control/notlshosts/")
+        || !stralloc_catb(&tmp, partner_fqdn, str_len(partner_fqdn)+1))
+        temp_nomem();
+      if ((stat("control/tlshosts/exhaustivelist", &st) == 0) ||
+	  (stat(tmp.s, &st) == 0)) {
+         alloc_free(tmp.s);
+         return 0;
+      }
+      alloc_free(tmp.s);
+    }
+  }
+ 
+  if (!smtps) {
+    stralloc *sa = ehlokw.sa;
+    unsigned int len = ehlokw.len;
+    /* look for STARTTLS among EHLO keywords */
+    for ( ; len && case_diffs(sa->s, "STARTTLS"); ++sa, --len) ;
+    if (!len) {
+      if (!servercert) return 0;
+      out("ZNo TLS achieved while "); out((char *)servercert);
+      out(" exists"); smtptext.len = 0; TLS_QUIT;
+    }
+  }
+
+  SSL_library_init();
+  ctx = SSL_CTX_new(SSLv23_client_method());
+  if (!ctx) {
+    if (!smtps && !servercert) return 0;
+    smtptext.len = 0;
+    tls_quit_error("ZTLS error initializing ctx");
+  }
+
+  /* POODLE vulnerability */
+  SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
+
+  if (servercert) {
+    if (!SSL_CTX_load_verify_locations(ctx, servercert, NULL)) {
+      SSL_CTX_free(ctx);
+      smtptext.len = 0;
+      out("ZTLS unable to load "); tls_quit_error(servercert);
+    }
+    /* set the callback here; SSL_set_verify didn't work before 0.9.6c */
+    SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, verify_cb);
+  }
+
+  /* let the other side complain if it needs a cert and we don't have one */
+# define CLIENTCERT "control/clientcert.pem"
+  if (SSL_CTX_use_certificate_chain_file(ctx, CLIENTCERT))
+    SSL_CTX_use_RSAPrivateKey_file(ctx, CLIENTCERT, SSL_FILETYPE_PEM);
+# undef CLIENTCERT
+
+#if OPENSSL_VERSION_NUMBER >= 0x10101000L
+  SSL_CTX_set_post_handshake_auth(ctx, 1);
+#endif
+
+  myssl = SSL_new(ctx);
+  SSL_CTX_free(ctx);
+  if (!myssl) {
+    if (!smtps && !servercert) return 0;
+    smtptext.len = 0;
+    tls_quit_error("ZTLS error initializing ssl");
+  }
+
+  if (!smtps) substdio_putsflush(&smtpto, "STARTTLS\r\n");
+
+  /* while the server is preparing a response, do something else */
+  if (control_readfile(&saciphers, "control/tlsclientciphers", 0) == -1)
+    { SSL_free(myssl); temp_control(); }
+  if (saciphers.len) {
+    for (i = 0; i < saciphers.len - 1; ++i)
+      if (!saciphers.s[i]) saciphers.s[i] = ':';
+    ciphers = saciphers.s;
+  }
+  else ciphers = "DEFAULT";
+  SSL_set_cipher_list(myssl, ciphers);
+  alloc_free(saciphers.s);
+
+  SSL_set_fd(myssl, smtpfd);
+
+  /* read the response to STARTTLS */
+  if (!smtps) {
+    if (smtpcode() != 220) {
+      SSL_free(myssl);
+      if (!servercert) return 0;
+      out("ZSTARTTLS rejected while ");
+      out((char *)servercert); out(" exists"); TLS_QUIT;
+    }
+    smtptext.len = 0;
+  }
+
+  ssl = myssl;
+  if (ssl_timeoutconn(timeout, smtpfd, smtpfd, ssl) <= 0)
+    tls_quit("ZTLS connect failed", ssl_error_str());
+
+  if (servercert) {
+    X509 *peercert;
+    STACK_OF(GENERAL_NAME) *gens;
+    int found_gen_dns = 0;
+    int matched_gen_dns = 0;
+
+    int r = SSL_get_verify_result(ssl);
+    if (r != X509_V_OK) {
+      out("ZTLS unable to verify server with ");
+      tls_quit(servercert, X509_verify_cert_error_string(r));
+    }
+    alloc_free(servercert);
+
+    peercert = SSL_get_peer_certificate(ssl);
+    if (!peercert) {
+      out("ZTLS unable to verify server ");
+      tls_quit(partner_fqdn, "no certificate provided");
+    }
+
+    /* RFC 2595 section 2.4: find a matching name
+     * first find a match among alternative names */
+    gens = X509_get_ext_d2i(peercert, NID_subject_alt_name, 0, 0);
+    if (gens) {
+      for (i = 0, r = sk_GENERAL_NAME_num(gens); i < r; ++i)
+      {
+        const GENERAL_NAME *gn = sk_GENERAL_NAME_value(gens, i);
+        if (gn->type == GEN_DNS){
+          found_gen_dns = 1;
+          if (match_partner(gn->d.ia5->data, gn->d.ia5->length)){
+            matched_gen_dns = 1;
+            break;
+          }
+        }
+      }
+      sk_GENERAL_NAME_pop_free(gens, GENERAL_NAME_free);
+    }
+
+    /* no SubjectAltName of type DNS found, look up commonName */
+    if (!found_gen_dns) {
+      stralloc peer = {0};
+      X509_NAME *subj = X509_get_subject_name(peercert);
+      i = X509_NAME_get_index_by_NID(subj, NID_commonName, -1);
+      if (i >= 0) {
+        const ASN1_STRING *s = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(subj, i));
+        if (s) { peer.len = s->length; peer.s = s->data; }
+      }
+      if (peer.len <= 0) {
+        out("ZTLS unable to verify server ");
+        tls_quit(partner_fqdn, "certificate contains no valid commonName");
+      }
+      if (!match_partner(peer.s, peer.len)) {
+        out("ZTLS unable to verify server "); out(partner_fqdn);
+        out(": received certificate for "); outsafe(&peer); TLS_QUIT;
+      }
+    } else if (!matched_gen_dns) {
+      out("ZTLS unable to verify server ");
+      tls_quit(partner_fqdn, "certificate contains no matching dNSNnames");
+    }
+
+    X509_free(peercert);
+  }
+
+  if (smtps) if (smtpcode() != 220)
+    quit("ZTLS Connected to "," but greeting failed");
+
+  return 1;
+}
+#endif
+
 stralloc recip = {0};
 
 void smtp()
@@ -221,15 +545,54 @@ void smtp()
   unsigned long code;
   int flagbother;
   int i;
+
+#ifndef PORT_SMTP
+  /* the qmtpc patch uses smtp_port and undefines PORT_SMTP */
+# define port smtp_port
+#endif
+
+#ifdef TLS
+# ifdef MXPS
+  if (type == 'S') smtps = 1;
+  else if (type != 's')
+# endif
+    if (port == 465) smtps = 1;
+  if (!smtps)
+#endif
  
   if (smtpcode() != 220) quit("ZConnected to "," but greeting failed");
  
+#ifdef EHLO
+# ifdef TLS
+  if (!smtps)
+# endif
+  code = ehlo();
+
+# ifdef TLS
+  if (tls_init())
+    /* RFC2487 says we should issue EHLO (even if we might not need
+     * extensions); at the same time, it does not prohibit a server
+     * to reject the EHLO and make us fallback to HELO */
+    code = ehlo();
+# endif
+
+  if (code == 250) {
+    /* add EHLO response checks here */
+
+    /* and if EHLO failed, use HELO */
+  } else {
+#endif
+ 
   substdio_puts(&smtpto,"HELO ");
   substdio_put(&smtpto,helohost.s,helohost.len);
   substdio_puts(&smtpto,"\r\n");
   substdio_flush(&smtpto);
   if (smtpcode() != 250) quit("ZConnected to "," but my name was rejected");
  
+#ifdef EHLO
+  }
+#endif
+ 
   substdio_puts(&smtpto,"MAIL FROM:<");
   substdio_put(&smtpto,sender.s,sender.len);
   substdio_puts(&smtpto,">\r\n");
@@ -417,6 +780,9 @@ char **argv;
     if (timeoutconn(smtpfd,&ip.ix[i].ip,(unsigned int) port,timeoutconnect) == 0) {
       tcpto_err(&ip.ix[i].ip,0);
       partner = ip.ix[i].ip;
+#ifdef TLS
+      partner_fqdn = ip.ix[i].fqdn;
+#endif
       smtp(); /* does not return */
     }
     tcpto_err(&ip.ix[i].ip,errno == error_timeout);
diff --git a/qmail-smtpd.8 b/qmail-smtpd.8
index 4eeae49..1a5dc9c 100644
--- a/qmail-smtpd.8
+++ b/qmail-smtpd.8
@@ -14,6 +14,15 @@ must be supplied several environment variables;
 see
 .BR tcp-environ(5) .
 
+If the environment variable
+.B SMTPS
+is non-empty,
+.B qmail-smtpd
+starts a TLS session (to support the deprecated SMTPS protocol,
+normally on port 465). Otherwise,
+.B qmail-smtpd
+offers the STARTTLS extension to ESMTP.
+
 .B qmail-smtpd
 is responsible for counting hops.
 It rejects any message with 100 or more 
@@ -49,6 +58,19 @@ may be of the form
 .BR @\fIhost ,
 meaning every address at
 .IR host .
+
+.TP 5
+.I clientca.pem
+A list of Certifying Authority (CA) certificates that are used to verify
+the client-presented certificates during a TLS-encrypted session.
+
+.TP 5
+.I clientcrl.pem
+A list of Certificate Revocation Lists (CRLs). If present it
+should contain the CRLs of the CAs in 
+.I clientca.pem 
+and client certs will be checked for revocation.
+
 .TP 5
 .I databytes
 Maximum number of bytes allowed in a message,
@@ -76,6 +98,14 @@ If the environment variable
 .B DATABYTES
 is set, it overrides
 .IR databytes .
+
+.TP 5
+.I dh2048.pem
+If these 2048 bit DH parameters are provided,
+.B qmail-smtpd
+will use them for TLS sessions instead of generating one on-the-fly 
+(which is very timeconsuming).
+
 .TP 5
 .I localiphost
 Replacement host name for local IP addresses.
@@ -151,6 +181,19 @@ may include wildcards:
 
 Envelope recipient addresses without @ signs are
 always allowed through.
+
+.TP 5
+.I rsa2048.pem
+If this 2048 bit RSA key is provided,
+.B qmail-smtpd
+will use it for TLS sessions instead of generating one on-the-fly.
+
+.TP 5
+.I servercert.pem
+SSL certificate to be presented to clients in TLS-encrypted sessions. 
+Should contain both the certificate and the private key. Certifying Authority
+(CA) and intermediate certificates can be added at the end of the file.
+
 .TP 5
 .I smtpgreeting
 SMTP greeting message.
@@ -169,6 +212,24 @@ Number of seconds
 .B qmail-smtpd
 will wait for each new buffer of data from the remote SMTP client.
 Default: 1200.
+
+.TP 5
+.I tlsclients
+A list of email addresses. When relay rules would reject an incoming message,
+.B qmail-smtpd
+can allow it if the client presents a certificate that can be verified against
+the CA list in
+.I clientca.pem
+and the certificate email address is in
+.IR tlsclients .
+
+.TP 5
+.I tlsserverciphers
+A set of OpenSSL cipher strings. Multiple ciphers contained in a
+string should be separated by a colon. If the environment variable
+.B TLSCIPHERS
+is set to such a string, it takes precedence.
+
 .SH "SEE ALSO"
 tcp-env(1),
 tcp-environ(5),
diff --git a/qmail-smtpd.c b/qmail-smtpd.c
index c12bf16..1651ef5 100644
--- a/qmail-smtpd.c
+++ b/qmail-smtpd.c
@@ -28,9 +28,27 @@
 unsigned int databytes = 0;
 int timeout = 1200;
 
+static const char *protocol = "SMTP";
+
+#ifdef TLS
+#include <sys/stat.h>
+#include "tls.h"
+#include "ssl_timeoutio.h"
+
+void tls_init();
+int tls_verify();
+void tls_nogateway();
+int ssl_rfd = -1, ssl_wfd = -1; /* SSL_get_Xfd() are broken */
+#endif
+
 int safewrite(fd,buf,len) int fd; char *buf; int len;
 {
   int r;
+#ifdef TLS
+  if (ssl && fd == ssl_wfd)
+    r = ssl_timeoutwrite(timeout, ssl_rfd, ssl_wfd, ssl, buf, len);
+  else
+#endif
   r = timeoutwrite(timeout,fd,buf,len);
   if (r <= 0) _exit(1);
   return r;
@@ -50,7 +68,16 @@ void die_ipme() { out("421 unable to figure out my IP addresses (#4.3.0)\r\n");
 void straynewline() { out("451 See https://cr.yp.to/docs/smtplf.html.\r\n"); flush(); _exit(1); }
 
 void err_bmf() { out("553 sorry, your envelope sender is in my badmailfrom list (#5.7.1)\r\n"); }
+#ifndef TLS
 void err_nogateway() { out("553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)\r\n"); }
+#else
+void err_nogateway()
+{
+  out("553 sorry, that domain isn't in my list of allowed rcpthosts");
+  tls_nogateway();
+  out(" (#5.7.1)\r\n");
+}
+#endif
 void err_unimpl(arg) char *arg; { out("502 unimplemented (#5.5.1)\r\n"); }
 void err_syntax() { out("555 syntax error (#5.5.4)\r\n"); }
 void err_wantmail() { out("503 MAIL first (#5.5.1)\r\n"); }
@@ -131,6 +158,11 @@ void setup()
   if (!remotehost) remotehost = "unknown";
   remoteinfo = env_get("TCPREMOTEINFO");
   relayclient = env_get("RELAYCLIENT");
+
+#ifdef TLS
+  if (env_get("SMTPS")) { smtps = 1; tls_init(); }
+  else
+#endif
   dohelo(remotehost);
 }
 
@@ -213,6 +245,9 @@ int addrallowed()
   int r;
   r = rcpthosts(addr.s,str_len(addr.s));
   if (r == -1) die_control();
+#ifdef TLS
+  if (r == 0) if (tls_verify()) r = -2;
+#endif
   return r;
 }
 
@@ -227,9 +262,18 @@ void smtp_helo(arg) char *arg;
   smtp_greet("250 "); out("\r\n");
   seenmail = 0; dohelo(arg);
 }
+/* ESMTP extensions are published here */
 void smtp_ehlo(arg) char *arg;
 {
-  smtp_greet("250-"); out("\r\n250-PIPELINING\r\n250 8BITMIME\r\n");
+#ifdef TLS
+  struct stat st;
+#endif
+  smtp_greet("250-");
+#ifdef TLS
+  if (!ssl && (stat("control/servercert.pem",&st) == 0))
+    out("\r\n250-STARTTLS");
+#endif
+  out("\r\n250-PIPELINING\r\n250 8BITMIME\r\n");
   seenmail = 0; dohelo(arg);
 }
 void smtp_rset(arg) char *arg;
@@ -269,6 +313,11 @@ int saferead(fd,buf,len) int fd; char *buf; int len;
 {
   int r;
   flush();
+#ifdef TLS
+  if (ssl && fd == ssl_rfd)
+    r = ssl_timeoutread(timeout, ssl_rfd, ssl_wfd, ssl, buf, len);
+  else
+#endif
   r = timeoutread(timeout,fd,buf,len);
   if (r == -1) if (errno == error_timeout) die_alarm();
   if (r <= 0) die_read();
@@ -277,6 +326,9 @@ int saferead(fd,buf,len) int fd; char *buf; int len;
 
 char ssinbuf[1024];
 substdio ssin = SUBSTDIO_FDBUF(saferead,0,ssinbuf,sizeof ssinbuf);
+#ifdef TLS
+void flush_io() { ssin.p = 0; flush(); }
+#endif
 
 struct qmail qqt;
 unsigned int bytestooverflow = 0;
@@ -378,7 +430,7 @@ void smtp_data(arg) char *arg; {
   qp = qmail_qp(&qqt);
   out("354 go ahead\r\n");
  
-  received(&qqt,"SMTP",local,remoteip,remotehost,remoteinfo,fakehelo);
+  received(&qqt,protocol,local,remoteip,remotehost,remoteinfo,fakehelo);
   blast(&hops);
   hops = (hops >= MAXHOPS);
   if (hops) qmail_fail(&qqt);
@@ -394,6 +446,271 @@ void smtp_data(arg) char *arg; {
   out("\r\n");
 }
 
+#ifdef TLS
+stralloc proto = {0};
+int ssl_verified = 0;
+const char *ssl_verify_err = 0;
+
+void smtp_tls(char *arg)
+{
+  if (ssl) err_unimpl();
+  else if (*arg) out("501 Syntax error (no parameters allowed) (#5.5.4)\r\n");
+  else tls_init();
+}
+
+RSA *tmp_rsa_cb(SSL *ssl, int export, int keylen)
+{
+  RSA *rsa;
+
+  if (!export) keylen = 2048;
+  if (keylen == 2048) {
+    FILE *in = fopen("control/rsa2048.pem", "r");
+    if (in) {
+      rsa = PEM_read_RSAPrivateKey(in, NULL, NULL, NULL);
+      fclose(in);
+      if (rsa) return rsa;
+    }
+  }
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+  BIGNUM *e; /*exponent */
+  e = BN_new(); 
+  BN_set_word(e, RSA_F4);
+  if (RSA_generate_key_ex(rsa, keylen, e, NULL) == 1)
+    return rsa;
+  return NULL;
+#else
+  return RSA_generate_key(keylen, RSA_F4, NULL, NULL);
+#endif
+}
+
+DH *tmp_dh_cb(SSL *ssl, int export, int keylen)
+{
+  DH *dh;
+
+  if (!export) keylen = 2048;
+  if (keylen == 2048) {
+    FILE *in = fopen("control/dh2048.pem", "r");
+    if (in) {
+      dh = PEM_read_DHparams(in, NULL, NULL, NULL);
+      fclose(in);
+      if (dh) return dh;
+    }
+  }
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+  if((dh = DH_new()) && (DH_generate_parameters_ex(dh, keylen, DH_GENERATOR_2, NULL) == 1))
+    return dh;
+  return NULL;
+#else
+  return DH_generate_parameters(keylen, DH_GENERATOR_2, NULL, NULL);
+#endif
+} 
+
+/* don't want to fail handshake if cert isn't verifiable */
+int verify_cb(int preverify_ok, X509_STORE_CTX *x509_ctx) { return 1; }
+
+void tls_nogateway()
+{
+  /* there may be cases when relayclient is set */
+  if (!ssl || relayclient) return;
+  out("; no valid cert for gatewaying");
+  if (ssl_verify_err) { out(": "); out(ssl_verify_err); }
+}
+void tls_out(const char *s1, const char *s2)
+{
+  out("454 TLS "); out(s1);
+  if (s2) { out(": "); out(s2); }
+  out(" (#4.3.0)\r\n"); flush();
+}
+void tls_err(const char *s) { tls_out(s, ssl_error()); if (smtps) die_read(); }
+
+# define CLIENTCA "control/clientca.pem"
+# define CLIENTCRL "control/clientcrl.pem"
+# define SERVERCERT "control/servercert.pem"
+
+int tls_verify()
+{
+  stralloc clients = {0};
+  struct constmap mapclients;
+
+  if (!ssl || relayclient || ssl_verified) return 0;
+  ssl_verified = 1; /* don't do this twice */
+
+  /* request client cert to see if it can be verified by one of our CAs
+   * and the associated email address matches an entry in tlsclients */
+  switch (control_readfile(&clients, "control/tlsclients", 0))
+  {
+  case 1:
+    if (constmap_init(&mapclients, clients.s, clients.len, 0)) {
+      /* if CLIENTCA contains all the standard root certificates, a
+       * 0.9.6b client might fail with SSL_R_EXCESSIVE_MESSAGE_SIZE;
+       * it is probably due to 0.9.6b supporting only 8k key exchange
+       * data while the 0.9.6c release increases that limit to 100k */
+      STACK_OF(X509_NAME) *sk = SSL_load_client_CA_file(CLIENTCA);
+      if (sk) {
+        SSL_set_client_CA_list(ssl, sk);
+        SSL_set_verify(ssl, SSL_VERIFY_PEER, verify_cb);
+        break;
+      }
+      constmap_free(&mapclients);
+    }
+  case 0: alloc_free(clients.s); return 0;
+  case -1: die_control();
+  }
+
+  if (ssl_timeoutrehandshake(timeout, ssl_rfd, ssl_wfd, ssl) <= 0) {
+    const char *err = ssl_error_str();
+    tls_out("rehandshake failed", err); die_read();
+  }
+
+  do { /* one iteration */
+    X509 *peercert;
+    X509_NAME *subj;
+    stralloc email = {0};
+
+    int n = SSL_get_verify_result(ssl);
+    if (n != X509_V_OK)
+      { ssl_verify_err = X509_verify_cert_error_string(n); break; }
+    peercert = SSL_get_peer_certificate(ssl);
+    if (!peercert) break;
+
+    subj = X509_get_subject_name(peercert);
+    n = X509_NAME_get_index_by_NID(subj, NID_pkcs9_emailAddress, -1);
+    if (n >= 0) {
+      const ASN1_STRING *s = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(subj, n));
+      if (s) { email.len = s->length; email.s = s->data; }
+    }
+
+    if (email.len <= 0)
+      ssl_verify_err = "contains no email address";
+    else if (!constmap(&mapclients, email.s, email.len))
+      ssl_verify_err = "email address not in my list of tlsclients";
+    else {
+      /* add the cert email to the proto if it helped allow relaying */
+      --proto.len;
+      if (!stralloc_cats(&proto, "\n  (cert ") /* continuation line */
+        || !stralloc_catb(&proto, email.s, email.len)
+        || !stralloc_cats(&proto, ")")
+        || !stralloc_0(&proto)) die_nomem();
+      protocol = proto.s;
+      relayclient = "";
+      /* also inform qmail-queue */
+      if (!env_put("RELAYCLIENT=")) die_nomem();
+    }
+
+    X509_free(peercert);
+  } while (0);
+  constmap_free(&mapclients); alloc_free(clients.s);
+
+  /* we are not going to need this anymore: free the memory */
+  SSL_set_client_CA_list(ssl, NULL);
+  SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL);
+
+  return relayclient ? 1 : 0;
+}
+
+void tls_init()
+{
+  SSL *myssl;
+  SSL_CTX *ctx;
+  const char *ciphers;
+  stralloc saciphers = {0};
+  X509_STORE *store;
+  X509_LOOKUP *lookup;
+  int session_id_context = 1; /* anything will do */
+
+  SSL_library_init();
+
+  /* a new SSL context with the bare minimum of options */
+  ctx = SSL_CTX_new(SSLv23_server_method());
+  if (!ctx) { tls_err("unable to initialize ctx"); return; }
+
+  /* POODLE vulnerability */
+  SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
+
+  /* renegotiation should include certificate request */
+  SSL_CTX_set_options(ctx, SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION);
+
+  /* never bother the application with retries if the transport is blocking */
+  SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);
+
+  /* relevant in renegotiation */
+  SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_OFF);
+  if (!SSL_CTX_set_session_id_context(ctx, (void *)&session_id_context,
+                                        sizeof(session_id_context))) 
+    { SSL_CTX_free(ctx); tls_err("failed to set session_id_context"); return; }
+
+  if (!SSL_CTX_use_certificate_chain_file(ctx, SERVERCERT))
+    { SSL_CTX_free(ctx); tls_err("missing certificate"); return; }
+  SSL_CTX_load_verify_locations(ctx, CLIENTCA, NULL);
+
+  /* crl checking */
+  store = SSL_CTX_get_cert_store(ctx);
+  if ((lookup = X509_STORE_add_lookup(store, X509_LOOKUP_file())) &&
+      (X509_load_crl_file(lookup, CLIENTCRL, X509_FILETYPE_PEM) == 1))
+    X509_STORE_set_flags(store, X509_V_FLAG_CRL_CHECK |
+                                X509_V_FLAG_CRL_CHECK_ALL);
+  
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+  /* support ECDH */
+  SSL_CTX_set_ecdh_auto(ctx,1);
+#endif
+
+  SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, NULL);
+
+  /* a new SSL object, with the rest added to it directly to avoid copying */
+  myssl = SSL_new(ctx);
+  SSL_CTX_free(ctx);
+  if (!myssl) { tls_err("unable to initialize ssl"); return; }
+
+  /* this will also check whether public and private keys match */
+  if (!SSL_use_RSAPrivateKey_file(myssl, SERVERCERT, SSL_FILETYPE_PEM))
+    { SSL_free(myssl); tls_err("no valid RSA private key"); return; }
+
+  ciphers = env_get("TLSCIPHERS");
+  if (!ciphers) {
+    if (control_readfile(&saciphers, "control/tlsserverciphers", 0) == -1)
+      { SSL_free(myssl); die_control(); }
+    if (saciphers.len) { /* convert all '\0's except the last one to ':' */
+      int i;
+      for (i = 0; i < saciphers.len - 1; ++i)
+        if (!saciphers.s[i]) saciphers.s[i] = ':';
+      ciphers = saciphers.s;
+    }
+  }
+  if (!ciphers || !*ciphers) ciphers = "DEFAULT";
+  SSL_set_cipher_list(myssl, ciphers);
+  alloc_free(saciphers.s);
+
+  SSL_set_tmp_rsa_callback(myssl, tmp_rsa_cb);
+  SSL_set_tmp_dh_callback(myssl, tmp_dh_cb);
+  SSL_set_rfd(myssl, ssl_rfd = substdio_fileno(&ssin));
+  SSL_set_wfd(myssl, ssl_wfd = substdio_fileno(&ssout));
+
+  if (!smtps) { out("220 ready for tls\r\n"); flush(); }
+
+  if (ssl_timeoutaccept(timeout, ssl_rfd, ssl_wfd, myssl) <= 0) {
+    /* neither cleartext nor any other response here is part of a standard */
+    const char *err = ssl_error_str();
+    tls_out("connection failed", err); ssl_free(myssl); die_read();
+  }
+  ssl = myssl;
+
+  /* populate the protocol string, used in Received */
+  if (!stralloc_copys(&proto, "ESMTPS (")
+    || !stralloc_cats(&proto, SSL_get_cipher(ssl))
+    || !stralloc_cats(&proto, " encrypted)")) die_nomem();
+  if (!stralloc_0(&proto)) die_nomem();
+  protocol = proto.s;
+
+  /* have to discard the pre-STARTTLS HELO/EHLO argument, if any */
+  dohelo(remotehost);
+}
+
+# undef SERVERCERT
+# undef CLIENTCA
+
+#endif
+
 struct commands smtpcommands[] = {
   { "rcpt", smtp_rcpt, 0 }
 , { "mail", smtp_mail, 0 }
@@ -403,6 +720,9 @@ struct commands smtpcommands[] = {
 , { "ehlo", smtp_ehlo, flush }
 , { "rset", smtp_rset, 0 }
 , { "help", smtp_help, flush }
+#ifdef TLS
+, { "starttls", smtp_tls, flush_io }
+#endif
 , { "noop", err_noop, flush }
 , { "vrfy", err_vrfy, flush }
 , { 0, err_unimpl, flush }
diff --git a/ssl_timeoutio.c b/ssl_timeoutio.c
new file mode 100644
index 0000000..ac33c7c
--- /dev/null
+++ b/ssl_timeoutio.c
@@ -0,0 +1,126 @@
+#ifdef TLS
+#include "select.h"
+#include "error.h"
+#include "ndelay.h"
+#include "now.h"
+#include "ssl_timeoutio.h"
+
+int ssl_timeoutio(int (*fun)(),
+  int t, int rfd, int wfd, SSL *ssl, char *buf, int len)
+{
+  int n;
+  const datetime_sec end = (datetime_sec)t + now();
+
+  do {
+    fd_set fds;
+    struct timeval tv;
+
+    const int r = buf ? fun(ssl, buf, len) : fun(ssl);
+    if (r > 0) return r;
+
+    t = end - now();
+    if (t < 0) break;
+    tv.tv_sec = (time_t)t; tv.tv_usec = 0;
+
+    FD_ZERO(&fds);
+    switch (SSL_get_error(ssl, r))
+    {
+    default: return r; /* some other error */
+    case SSL_ERROR_WANT_READ:
+      FD_SET(rfd, &fds); n = select(rfd + 1, &fds, NULL, NULL, &tv);
+      break;
+    case SSL_ERROR_WANT_WRITE:
+      FD_SET(wfd, &fds); n = select(wfd + 1, NULL, &fds, NULL, &tv);
+      break;
+    }
+
+    /* n is the number of descriptors that changed status */
+  } while (n > 0);
+
+  if (n != -1) errno = error_timeout;
+  return -1;
+}
+
+int ssl_timeoutaccept(int t, int rfd, int wfd, SSL *ssl)
+{
+  int r;
+
+  /* if connection is established, keep NDELAY */
+  if (ndelay_on(rfd) == -1 || ndelay_on(wfd) == -1) return -1;
+  r = ssl_timeoutio(SSL_accept, t, rfd, wfd, ssl, NULL, 0);
+
+  if (r <= 0) { ndelay_off(rfd); ndelay_off(wfd); }
+  else SSL_set_mode(ssl, SSL_MODE_ENABLE_PARTIAL_WRITE);
+
+  return r;
+}
+
+int ssl_timeoutconn(int t, int rfd, int wfd, SSL *ssl)
+{
+  int r;
+
+  /* if connection is established, keep NDELAY */
+  if (ndelay_on(rfd) == -1 || ndelay_on(wfd) == -1) return -1;
+  r = ssl_timeoutio(SSL_connect, t, rfd, wfd, ssl, NULL, 0);
+
+  if (r <= 0) { ndelay_off(rfd); ndelay_off(wfd); }
+  else SSL_set_mode(ssl, SSL_MODE_ENABLE_PARTIAL_WRITE);
+
+  return r;
+}
+
+int ssl_timeoutrehandshake(int t, int rfd, int wfd, SSL *ssl)
+{
+  int r=0;
+
+#if OPENSSL_VERSION_NUMBER >= 0x10101000L
+  if (SSL_version(ssl) >= TLS1_3_VERSION){
+    if(SSL_verify_client_post_handshake(ssl) != 1)
+      return -EPROTO;
+  } else
+#endif
+  { 
+    r =  SSL_renegotiate(ssl);
+    if (r<=0) return r;
+  }
+
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+  char buf[1]; /* dummy read buffer */
+  struct timeval tv;
+  fd_set fds;
+  r = ssl_timeoutio(SSL_do_handshake, t, rfd, wfd, ssl, NULL, 0);
+  if (r <=0) return r;
+#if OPENSSL_VERSION_NUMBER >= 0x10101000L
+  if (SSL_version(ssl) >= TLS1_3_VERSION) return r;
+#endif
+
+  tv.tv_sec = (time_t)t; tv.tv_usec = 0;
+  FD_ZERO(&fds);  FD_SET(rfd, &fds);
+  if ((r = select(rfd + 1, &fds, NULL, NULL, &tv)>0) && FD_ISSET(rfd, &fds)){
+    r = SSL_read(ssl, buf, 1);
+    if (SSL_get_error(ssl, r) == SSL_ERROR_WANT_READ) r = 1; /*ignore */
+  }
+  if (r <=0) return r;
+#else
+  r = ssl_timeoutio(SSL_do_handshake, t, rfd, wfd, ssl, NULL, 0);
+  if (r <= 0 || ssl->type == SSL_ST_CONNECT) return r;
+
+  /* this is for the server only */
+  ssl->state = SSL_ST_ACCEPT;
+#endif
+  return ssl_timeoutio(SSL_do_handshake, t, rfd, wfd, ssl, NULL, 0);
+}
+
+int ssl_timeoutread(int t, int rfd, int wfd, SSL *ssl, char *buf, int len)
+{
+  if (!buf) return 0;
+  if (SSL_pending(ssl)) return SSL_read(ssl, buf, len);
+  return ssl_timeoutio(SSL_read, t, rfd, wfd, ssl, buf, len);
+}
+
+int ssl_timeoutwrite(int t, int rfd, int wfd, SSL *ssl, char *buf, int len)
+{
+  if (!buf) return 0;
+  return ssl_timeoutio(SSL_write, t, rfd, wfd, ssl, buf, len);
+}
+#endif
diff --git a/ssl_timeoutio.h b/ssl_timeoutio.h
new file mode 100644
index 0000000..5efe07d
--- /dev/null
+++ b/ssl_timeoutio.h
@@ -0,0 +1,21 @@
+#ifndef SSL_TIMEOUTIO_H
+#define SSL_TIMEOUTIO_H
+
+#include <openssl/ssl.h>
+
+/* the version is like this: 0xMNNFFPPS: major minor fix patch status */
+#if OPENSSL_VERSION_NUMBER < 0x00908000L
+# error "Need OpenSSL version at least 0.9.8"
+#endif
+
+int ssl_timeoutconn(int t, int rfd, int wfd, SSL *ssl);
+int ssl_timeoutaccept(int t, int rfd, int wfd, SSL *ssl);
+int ssl_timeoutrehandshake(int t, int rfd, int wfd, SSL *ssl);
+
+int ssl_timeoutread(int t, int rfd, int wfd, SSL *ssl, char *buf, int len);
+int ssl_timeoutwrite(int t, int rfd, int wfd, SSL *ssl, char *buf, int len);
+
+int ssl_timeoutio(
+  int (*fun)(), int t, int rfd, int wfd, SSL *ssl, char *buf, int len);
+
+#endif
diff --git a/tls.c b/tls.c
new file mode 100644
index 0000000..b48142c
--- /dev/null
+++ b/tls.c
@@ -0,0 +1,27 @@
+#ifdef TLS
+#include "exit.h"
+#include "error.h"
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+
+int smtps = 0;
+SSL *ssl = NULL;
+
+void ssl_free(SSL *myssl) { SSL_shutdown(myssl); SSL_free(myssl); }
+void ssl_exit(int status) { if (ssl) ssl_free(ssl); _exit(status); }
+
+const char *ssl_error()
+{
+  int r = ERR_get_error();
+  if (!r) return NULL;
+  SSL_load_error_strings();
+  return ERR_error_string(r, NULL);
+}
+const char *ssl_error_str()
+{
+  const char *err = ssl_error();
+  if (err) return err;
+  if (!errno) return 0;
+  return (errno == error_timeout) ? "timed out" : error_str(errno);
+}
+#endif
diff --git a/tls.h b/tls.h
new file mode 100644
index 0000000..a4650af
--- /dev/null
+++ b/tls.h
@@ -0,0 +1,16 @@
+#ifndef TLS_H
+#define TLS_H
+
+#include <openssl/ssl.h>
+
+extern int smtps;
+extern SSL *ssl;
+
+void ssl_free(SSL *myssl);
+void ssl_exit(int status);
+# define _exit ssl_exit
+
+const char *ssl_error();
+const char *ssl_error_str();
+
+#endif
diff --git a/update_tmprsadh.sh b/update_tmprsadh.sh
new file mode 100644
index 0000000..beab94f
--- /dev/null
+++ b/update_tmprsadh.sh
@@ -0,0 +1,19 @@
+#!/bin/sh
+
+# Update temporary RSA and DH keys
+# Frederik Vermeulen 2004-05-31 GPL
+
+umask 0077 || exit 0
+
+export PATH="$PATH:/usr/local/bin/ssl:/usr/sbin"
+
+openssl genrsa -out QMAIL/control/rsa2048.new 2048 &&
+chmod 600 QMAIL/control/rsa2048.new &&
+chown UGQMAILD QMAIL/control/rsa2048.new &&
+mv -f QMAIL/control/rsa2048.new QMAIL/control/rsa2048.pem
+echo
+
+openssl dhparam -2 -out QMAIL/control/dh2048.new 2048 &&
+chmod 600 QMAIL/control/dh2048.new &&
+chown UGQMAILD QMAIL/control/dh2048.new &&
+mv -f QMAIL/control/dh2048.new QMAIL/control/dh2048.pem