Merge pull request #167 from HighwindsHipsApp/master

Fixed parent/child usage after initial fork in sslh-fork.c

COPYING

@@ -0,0 +1,339 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
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ChangeLog

@@ -1,3 +1,62 @@
+v1.19: 20JAN2018
+	Added 'syslog_facility' configuration option to
+	specify where to log.
+
+	TLS now supports SNI and ALPN (Travis Burtrum),
+	including support for Let's Encrypt challenges
+	(Jonathan McCrohan)
+
+	ADB probe. (Mike Frysinger)
+
+	Added per-protocol 'fork' option. (Oleg Oshmyan)
+
+	Added chroot option. (Mike Frysinger)
+
+	A truckload of bug fixes and documentation
+	improvements (Various contributors)
+
+v1.18:	29MAR2016
+	Added USELIBPCRE to make use of regex engine
+	optional.
+
+	Added support for RFC4366 SNI and RFC7301 ALPN
+	(Travis Burtrum)
+
+	Changed connection log to include the name of the probe that
+	triggered.
+
+	Changed configuration file format: 'probe' field is
+	no longer required, 'name' field can now contain
+	'tls' or 'regex', with corresponding options (see
+	example.cfg)
+	Added 'log_level' option to each protocol, which
+	allows to turn off generation of log at each
+	connection.
+	Added 'keepalive' option.
+
+v1.17: 	09MAR2015
+	Support RFC5952-style IPv6 addresses, e.g. [::]:443.
+
+	Transparant proxy support for FreeBSD.
+	(Ruben van Staveren)
+
+	Using -F with no argument will try
+	/etc/sslh/sslh.cfg and then /etc/sslh.cfg as
+	configuration files. (argument to -F can no longer
+	be separated from the option by a space, e.g. must
+	be -Ffoo.cfg)
+
+	Call setgroups() before setgid() (fixes potential
+	privilege escalation).
+	(Lars Vogdt)
+
+	Use portable way of getting modified time for OSX
+	support.
+	(Aaron Madlon-Kay)
+
+	Example configuration for fail2ban.
+	(Every Mouw)
+
 v1.16:	11FEB2014
 	Probes made more resilient, to incoming data
 	containing NULLs. Also made them behave properly

Makefile

@@ -1,11 +1,16 @@
 # Configuration
 
 VERSION=$(shell ./genver.sh -r)
+ENABLE_REGEX=1  # Enable regex probes
 USELIBCONFIG=1	# Use libconfig? (necessary to use configuration files)
-USELIBWRAP=	# Use libwrap?
+USELIBPCRE=1	# Use libpcre? (needed for regex on musl)
+USELIBWRAP?=	# Use libwrap?
 USELIBCAP=	# Use libcap?
+USESYSTEMD=     # Make use of systemd socket activation
 COV_TEST= 	# Perform test coverage?
-PREFIX=/usr/local
+PREFIX?=/usr
+BINDIR?=$(PREFIX)/sbin
+MANDIR?=$(PREFIX)/share/man/man8
 
 MAN=sslh.8.gz	# man page name
 
@@ -20,13 +25,24 @@ CC ?= gcc
 CFLAGS ?=-Wall -g $(CFLAGS_COV)
 
 LIBS=
-OBJS=common.o sslh-main.o probe.o
+OBJS=common.o sslh-main.o probe.o tls.o
+
+CONDITIONAL_TARGETS=
 
 ifneq ($(strip $(USELIBWRAP)),)
 	LIBS:=$(LIBS) -lwrap
 	CPPFLAGS+=-DLIBWRAP
 endif
 
+ifneq ($(strip $(ENABLE_REGEX)),)
+	CPPFLAGS+=-DENABLE_REGEX
+endif
+
+ifneq ($(strip $(USELIBPCRE)),)
+	CPPFLAGS+=-DLIBPCRE
+	LIBS:=$(LIBS) -lpcreposix
+endif
+
 ifneq ($(strip $(USELIBCONFIG)),)
 	LIBS:=$(LIBS) -lconfig
 	CPPFLAGS+=-DLIBCONFIG
@@ -37,9 +53,16 @@ ifneq ($(strip $(USELIBCAP)),)
 	CPPFLAGS+=-DLIBCAP
 endif
 
-all: sslh $(MAN) echosrv
+ifneq ($(strip $(USESYSTEMD)),)
+        LIBS:=$(LIBS) -lsystemd
+        CPPFLAGS+=-DSYSTEMD
+	CONDITIONAL_TARGETS+=systemd-sslh-generator
+endif
 
-.c.o: *.h
+
+all: sslh $(MAN) echosrv $(CONDITIONAL_TARGETS)
+
+.c.o: *.h version.h
 	$(CC) $(CFLAGS) $(CPPFLAGS) -c $<
 
 version.h:
@@ -47,6 +70,8 @@ version.h:
 
 sslh: sslh-fork sslh-select
 
+$(OBJS): version.h
+
 sslh-fork: version.h $(OBJS) sslh-fork.o Makefile common.h
 	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-fork sslh-fork.o $(OBJS) $(LIBS)
 	#strip sslh-fork
@@ -55,8 +80,11 @@ sslh-select: version.h $(OBJS) sslh-select.o Makefile common.h
 	$(CC) $(CFLAGS) $(LDFLAGS) -o sslh-select sslh-select.o $(OBJS) $(LIBS)
 	#strip sslh-select
 
-echosrv: $(OBJS) echosrv.o
-	$(CC) $(CFLAGS) $(LDFLAGS) -o echosrv echosrv.o probe.o common.o $(LIBS)
+systemd-sslh-generator: systemd-sslh-generator.o
+	$(CC) $(CFLAGS) $(LDFLAGS) -o systemd-sslh-generator systemd-sslh-generator.o -lconfig
+
+echosrv: version.h $(OBJS) echosrv.o
+	$(CC) $(CFLAGS) $(LDFLAGS) -o echosrv echosrv.o probe.o common.o tls.o $(LIBS)
 
 $(MAN): sslh.pod Makefile
 	pod2man --section=8 --release=$(VERSION) --center=" " sslh.pod | gzip -9 - > $(MAN)
@@ -68,25 +96,26 @@ release:
 
 # generic install: install binary and man page
 install: sslh $(MAN)
-	install -pD sslh-fork $(DESTDIR)$(PREFIX)/sbin/sslh
-	install -pD -m 0644 $(MAN) $(DESTDIR)$(PREFIX)/share/man/man8/$(MAN)
+	mkdir -p $(DESTDIR)/$(BINDIR)
+	mkdir -p $(DESTDIR)/$(MANDIR)
+	install -p sslh-fork $(DESTDIR)/$(BINDIR)/sslh
+	install -p -m 0644 $(MAN) $(DESTDIR)/$(MANDIR)/$(MAN)
 
 # "extended" install for Debian: install startup script
 install-debian: install sslh $(MAN)
 	sed -e "s+^PREFIX=+PREFIX=$(PREFIX)+" scripts/etc.init.d.sslh > /etc/init.d/sslh
 	chmod 755 /etc/init.d/sslh
-	cp scripts/etc.default.sslh /etc/default/sslh
 	update-rc.d sslh defaults
 
 uninstall:
-	rm -f $(DESTDIR)$(PREFIX)/sbin/sslh $(DESTDIR)$(PREFIX)/share/man/man8/$(MAN) $(DESTDIR)/etc/init.d/sslh $(DESTDIR)/etc/default/sslh
+	rm -f $(DESTDIR)$(BINDIR)/sslh $(DESTDIR)$(MANDIR)/$(MAN) $(DESTDIR)/etc/init.d/sslh $(DESTDIR)/etc/default/sslh
 	update-rc.d sslh remove
 
 distclean: clean
 	rm -f tags cscope.*
 
 clean:
-	rm -f sslh-fork sslh-select echosrv version.h $(MAN) *.o *.gcov *.gcno *.gcda *.png *.html *.css *.info
+	rm -f sslh-fork sslh-select echosrv version.h $(MAN) systemd-sslh-generator *.o *.gcov *.gcno *.gcda *.png *.html *.css *.info
 
 tags:
 	ctags --globals -T *.[ch]
@@ -97,4 +126,3 @@ cscope:
 
 test:
 	./t
-

README.md

@@ -59,6 +59,8 @@ of the Makefile:
   file. You will need `libconfig` headers to compile
   (`libconfig8-dev` in Debian).
 
+*  `USESYSTEMD` compiles support for using systemd socket activation.
+   You will need `systemd` headers to compile (`systemd-devel` in Fedora).
 
 Binaries
 --------
@@ -93,7 +95,8 @@ Installation
 
 		make
 		cp sslh-fork /usr/local/sbin/sslh
-		cp scripts/etc.default.sslh /etc/default/sslh
+		cp basic.cfg /etc/sslh.cfg
+                vi /etc/sslh.cfg
 
 * For Debian:
 
@@ -101,7 +104,7 @@ Installation
 	
 * For CentOS:
 
-		cp scripts/etc.rc.d.init.d.sslh /etc/rc.d/init.d/sslh
+		cp scripts/etc.rc.d.init.d.sslh.centos /etc/rc.d/init.d/sslh
 
 
 You might need to create links in /etc/rc<x>.d so that the server
@@ -113,14 +116,12 @@ start automatically at boot-up, e.g. under Debian:
 Configuration
 =============
 
-You can edit settings in /etc/default/sslh:
-
-	LISTEN=ifname:443
-	SSH=localhost:22
-	SSL=localhost:443
+If you use the scripts provided, sslh will get its
+configuration from /etc/sslh.cfg. Please refer to
+example.cfg for an overview of all the settings.
 
 A good scheme is to use the external name of the machine in
-`$LISTEN`, and bind `httpd` to `localhost:443` (instead of all
+`listen`, and bind `httpd` to `localhost:443` (instead of all
 binding to all interfaces): that way, HTTPS connections
 coming from inside your network don't need to go through
 `sslh`, and `sslh` is only there as a frontal for connections
@@ -134,7 +135,7 @@ i.e. that that is not `127.0.0.1` in the output of
 Libwrap support
 ---------------
 
-Sslh can optionnaly perform `libwrap` checks for the sshd
+Sslh can optionally perform `libwrap` checks for the sshd
 service: because the connection to `sshd` will be coming
 locally from `sslh`, `sshd` cannot determine the IP of the
 client.
@@ -144,14 +145,15 @@ OpenVPN support
 
 OpenVPN clients connecting to OpenVPN running with
 `-port-share` reportedly take more than one second between
-the time the TCP connexion is established and the time they
+the time the TCP connection is established and the time they
 send the first data packet. This results in `sslh` with
-default settings timing out and assuming an SSH connexion.
-To support OpenVPN connexions reliably, it is necessary to
+default settings timing out and assuming an SSH connection.
+To support OpenVPN connections reliably, it is necessary to
 increase `sslh`'s timeout to 5 seconds.
 
 Instead of using OpenVPN's port sharing, it is more reliable
-to use `sslh`'s `-o` option to get `sslh` to do the port sharing.
+to use `sslh`'s `--openvpn` option to get `sslh` to do the
+port sharing.
 
 Using proxytunnel with sslh
 ---------------------------
@@ -216,29 +218,118 @@ transparent proxying, just don't use it (or use the libcap method).
 Transparent proxy support
 -------------------------
 
-On Linux (only?) you can use the `--transparent` option to
-request transparent proying. This means services behind `sslh`
+On Linux and FreeBSD you can use the `--transparent` option to
+request transparent proxying. This means services behind `sslh`
 (Apache, `sshd` and so on) will see the external IP and ports
 as if the external world connected directly to them. This
 simplifies IP-based access control (or makes it possible at
 all).
 
+Linux:
+
 `sslh` needs extended rights to perform this: you'll need to
 give it `CAP_NET_ADMIN` capabilities (see appropriate chapter)
 or run it as root (but don't do that).
 
-The firewalling tables also need to be adjusted as follow.
-The example connects to HTTPS on 4443 -- adapt to your needs ;
-I don't think it is possible to have `httpd` listen to 443 in
+The firewalling tables also need to be adjusted as follows.
+I don't think it is possible to have `httpd` and `sslh` both listen to 443 in
 this scheme -- let me know if you manage that:
 
-	# iptables -t mangle -N SSLH
-	# iptables -t mangle -A  OUTPUT --protocol tcp --out-interface eth0 --sport 22 --jump SSLH
-	# iptables -t mangle -A OUTPUT --protocol tcp --out-interface eth0 --sport 4443 --jump SSLH
-	# iptables -t mangle -A SSLH --jump MARK --set-mark 0x1
-	# iptables -t mangle -A SSLH --jump ACCEPT
-	# ip rule add fwmark 0x1 lookup 100
-	# ip route add local 0.0.0.0/0 dev lo table 100
+	$ # Set route_localnet = 1 on all interfaces so that ssl can use "localhost" as destination
+	$ sysctl -w net.ipv4.conf.default.route_localnet=1
+	$ sysctl -w net.ipv4.conf.all.route_localnet=1
+
+	$ # DROP martian packets as they would have been if route_localnet was zero
+	$ # Note: packets not leaving the server aren't affected by this, thus sslh will still work
+	$ iptables -t raw -A PREROUTING ! -i lo -d 127.0.0.0/8 -j DROP
+	$ iptables -t mangle -A POSTROUTING ! -o lo -s 127.0.0.0/8 -j DROP
+
+	$ # Mark all connections made by ssl for special treatment (here sslh is run as user "sslh")
+	$ iptables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+
+	$ # Outgoing packets that should go to sslh instead have to be rerouted, so mark them accordingly (copying over the connection mark)
+	$ iptables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+	$ # Configure routing for those marked packets
+	$ ip rule add fwmark 0x1 lookup 100
+	$ ip route add local 0.0.0.0/0 dev lo table 100
+
+Tranparent proxying with IPv6 is similarly set up as follows:
+
+	$ # Set route_localnet = 1 on all interfaces so that ssl can use "localhost" as destination
+	$ # Not sure if this is needed for ipv6 though
+	$ sysctl -w net.ipv4.conf.default.route_localnet=1
+	$ sysctl -w net.ipv4.conf.all.route_localnet=1
+
+	$ # DROP martian packets as they would have been if route_localnet was zero
+	$ # Note: packets not leaving the server aren't affected by this, thus sslh will still work
+	$ ip6tables -t raw -A PREROUTING ! -i lo -d ::1/128 -j DROP
+	$ ip6tables -t mangle -A POSTROUTING ! -o lo -s ::1/128 -j DROP
+
+	$ # Mark all connections made by ssl for special treatment (here sslh is run as user "sslh")
+	$ ip6tables -t nat -A OUTPUT -m owner --uid-owner sslh -p tcp --tcp-flags FIN,SYN,RST,ACK SYN -j CONNMARK --set-xmark 0x01/0x0f
+
+	$ # Outgoing packets that should go to sslh instead have to be rerouted, so mark them accordingly (copying over the connection mark)
+	$ ip6tables -t mangle -A OUTPUT ! -o lo -p tcp -m connmark --mark 0x01/0x0f -j CONNMARK --restore-mark --mask 0x0f
+
+	$ # Configure routing for those marked packets
+	$ ip -6 rule add fwmark 0x1 lookup 100
+	$ ip -6 route add local ::/0 dev lo table 100
+
+Explanation:
+To be able to use `localhost` as destination in your sslh config along with transparent proxying
+you have to allow routing of loopback addresses as done above.
+This is something you usually should not do (see [this stackoverflow post](https://serverfault.com/questions/656279/how-to-force-linux-to-accept-packet-with-loopback-ip/656484#656484))
+The two `DROP` iptables rules emulate the behaviour of `route_localnet` set to off (with one small difference:
+allowing the reroute-check to happen after the fwmark is set on packets destined for sslh).
+See [this diagram](https://upload.wikimedia.org/wikipedia/commons/3/37/Netfilter-packet-flow.svg) for a good visualisation
+showing how packets will traverse the iptables chains.
+
+Note:
+You have to run `sslh` as dedicated user (in this example the user is also named `sslh`), to not mess up with your normal networking.
+These rules will allow you to connect directly to ssh on port
+22 (or to any other service behind sslh) as well as through sslh on port 443.
+
+Also remember that iptables configuration and ip routes and 
+rules won't be necessarily persisted after you reboot. Make 
+sure to save them properly. For example in CentOS7, you would 
+do `iptables-save > /etc/sysconfig/iptables`, and add both 
+`ip` commands to your `/etc/rc.local`.
+
+FreeBSD:
+
+Given you have no firewall defined yet, you can use the following configuration
+to have ipfw properly redirect traffic back to sslh
+
+	/etc/rc.conf
+	firewall_enable="YES"
+	firewall_type="open"
+	firewall_logif="YES"
+	firewall_coscripts="/etc/ipfw/sslh.rules"
+
+
+/etc/ipfw/sslh.rules
+
+	#! /bin/sh
+
+	# ssl
+	ipfw add 20000 fwd 192.0.2.1,443 log tcp from 192.0.2.1 8443 to any out
+	ipfw add 20010 fwd 2001:db8::1,443 log tcp from 2001:db8::1 8443 to any out
+
+	# ssh
+	ipfw add 20100 fwd 192.0.2.1,443 log tcp from 192.0.2.1 8022 to any out
+	ipfw add 20110 fwd 2001:db8::1,443 log tcp from 2001:db8::1 8022 to any out
+
+	# xmpp
+	ipfw add 20200 fwd 192.0.2.1,443 log tcp from 192.0.2.1 5222 to any out
+	ipfw add 20210 fwd 2001:db8::1,443 log tcp from 2001:db8::1 5222 to any out
+
+	# openvpn (running on other internal system)
+	ipfw add 20300 fwd 192.0.2.1,443 log tcp from 198.51.100.7 1194 to any out
+	ipfw add 20310 fwd 2001:db8::1,443 log tcp from 2001:db8:1::7 1194 to any out
+
+General notes:
+
 
 This will only work if `sslh` does not use any loopback
 addresses (no `127.0.0.1` or `localhost`), you'll need to use
@@ -249,6 +340,102 @@ explicit IP addresses (or names):
 This will not work:
 
 	sslh --listen 192.168.0.1:443 --ssh 127.0.0.1:22 --ssl 127.0.0.1:4443
+    
+Transparent proxying means the target server sees the real
+origin address, so it means if the client connects using
+IPv6, the server must also support IPv6. It is easy to
+support both IPv4 and IPv6 by configuring the server
+accordingly, and setting `sslh` to connect to a name that
+resolves to both IPv4 and IPv6, e.g.:
+
+        sslh --transparent --listen <extaddr>:443 --ssh insideaddr:22
+
+        /etc/hosts:
+        192.168.0.1  insideaddr
+        201::::2     insideaddr
+
+Upon incoming IPv6 connection, `sslh` will first try to
+connect to the IPv4 address (which will fail), then connect
+to the IPv6 address.
+
+Systemd Socket Activation
+-------------------------
+If compiled with `USESYSTEMD` then it is possible to activate 
+the service on demand and avoid running any code as root.
+
+In this mode any listen configuration options are ignored and 
+the sockets are passed by systemd to the service.
+
+Example socket unit:
+
+	[Unit]
+	Before=sslh.service
+	
+	[Socket]
+	ListenStream=1.2.3.4:443
+	ListenStream=5.6.7.8:444
+	ListenStream=9.10.11.12:445
+	FreeBind=true
+
+	[Install]
+	WantedBy=sockets.target
+
+Example service unit:
+
+	[Unit]
+	PartOf=sslh.socket
+	
+	[Service]
+	ExecStart=/usr/sbin/sslh -v -f --ssh 127.0.0.1:22 --ssl 127.0.0.1:443
+	KillMode=process
+	CapabilityBoundingSet=CAP_NET_BIND_SERVICE CAP_NET_ADMIN CAP_SETGID CAP_SETUID
+	PrivateTmp=true
+	PrivateDevices=true
+	ProtectSystem=full
+	ProtectHome=true
+	User=sslh
+
+
+With this setup only the socket needs to be enabled. The sslh service 
+will be started on demand and does not need to run as root to bind the 
+sockets as systemd has already bound and passed them over. If the sslh
+service is started on its own without the sockets being passed by systemd
+then it will look to use those defined on the command line or config
+file as usual. Any number of ListenStreams can be defined in the socket
+file and systemd will pass them all over to sslh to use as usual.
+
+To avoid inconsistency between starting via socket and starting directly
+via the service Requires=sslh.socket can be added to the service unit to
+mandate the use of the socket configuration.
+
+Rather than overwriting the entire socket file drop in values can be placed
+in /etc/systemd/system/sslh.socket.d/<name>.conf with additional ListenStream
+values that will be merged.
+
+In addition to the above with manual .socket file configuration there is an
+optional systemd generator which can be compiled - systemd-sslh-generator 
+
+This parses the /etc/sslh.cfg (or /etc/sslh/sslh.cfg file if that exists 
+instead) configuration file and dynamically generates a socket file to use.
+
+This will also merge with any sslh.socket.d drop in configuration but will be 
+overriden by a /etc/systemd/system/sslh.socket file.
+
+To use the generator place it in /usr/lib/systemd/system-generators and then
+call systemctl daemon-reload after any changes to /etc/sslh.cfg to generate 
+the new dynamic socket unit.
+
+Fail2ban
+--------
+
+If using transparent proxying, just use the standard ssh
+rules. If you can't or don't want to use transparent
+proxying, you can set `fail2ban` rules to block repeated ssh
+connections from an IP address (obviously this depends
+on the site, there might be legitimate reasons you would get
+many connections to ssh from the same IP address...)
+
+See example files in scripts/fail2ban.
 
 Comments? Questions?
 ====================

basic.cfg

@@ -9,6 +9,7 @@ transparent: false;
 timeout: 2;
 user: "nobody";
 pidfile: "/var/run/sslh.pid";
+chroot: "/var/empty";
 
 
 # Change hostname with your external address name.
@@ -19,11 +20,11 @@ listen:
 
 protocols:
 (
-     { name: "ssh"; service: "ssh"; host: "localhost"; port: "22"; probe: "builtin"; },
-     { name: "openvpn"; host: "localhost"; port: "1194"; probe: "builtin"; },
-     { name: "xmpp"; host: "localhost"; port: "5222"; probe: "builtin"; },
-     { name: "http"; host: "localhost"; port: "80"; probe: "builtin"; },
-     { name: "ssl"; host: "localhost"; port: "443"; probe: "builtin"; },
-     { name: "anyprot"; host: "localhost"; port: "443"; probe: "builtin"; }
+     { name: "ssh"; service: "ssh"; host: "localhost"; port: "22"; fork: true; },
+     { name: "openvpn"; host: "localhost"; port: "1194"; },
+     { name: "xmpp"; host: "localhost"; port: "5222"; },
+     { name: "http"; host: "localhost"; port: "80"; },
+     { name: "ssl"; host: "localhost"; port: "443"; log_level: 0; },
+     { name: "anyprot"; host: "localhost"; port: "443"; }
 );
 

common.c

@@ -4,19 +4,32 @@
  * No code here should assume whether sockets are blocking or not.
  **/
 
+#define SYSLOG_NAMES
 #define _GNU_SOURCE
+#include <stddef.h>
 #include <stdarg.h>
+#include <grp.h>
+
+#include <sys/types.h>
+#include <ifaddrs.h>
+#include <netinet/in.h>
 
 #include "common.h"
 #include "probe.h"
 
-/* Added to make the code compilable under CYGWIN 
+/* Added to make the code compilable under CYGWIN
  * */
 #ifndef SA_NOCLDWAIT
 #define SA_NOCLDWAIT 0
 #endif
 
-/* 
+/* Make use of systemd socket activation
+ * */
+#ifdef SYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
+
+/*
  * Settings that depend on the command line.  They're set in main(), but also
  * used in other places in common.c, and it'd be heavy-handed to pass it all as
  * parameters
@@ -28,7 +41,7 @@ int foreground = 0;
 int background = 0;
 int transparent = 0;
 int numeric = 0;
-const char *user_name, *pid_file;
+const char *user_name, *pid_file, *chroot_path, *facility = "auth";
 
 struct addrinfo *addr_listen = NULL; /* what addresses do we listen to? */
 
@@ -37,20 +50,49 @@ struct addrinfo *addr_listen = NULL; /* what addresses do we listen to? */
 int allow_severity =0, deny_severity = 0;
 #endif
 
+typedef enum {
+    CR_DIE,
+    CR_WARN
+} CR_ACTION;
+
 /* check result and die, printing the offending address and error */
-void check_res_dumpdie(int res, struct addrinfo *addr, char* syscall)
+void check_res_dump(CR_ACTION act, int res, struct addrinfo *addr, char* syscall)
 {
     char buf[NI_MAXHOST];
 
     if (res == -1) {
-        fprintf(stderr, "%s:%s: %s\n", 
-                sprintaddr(buf, sizeof(buf), addr), 
-                syscall, 
+        fprintf(stderr, "%s:%s: %s\n",
+                sprintaddr(buf, sizeof(buf), addr),
+                syscall,
                 strerror(errno));
-        exit(1);
+
+        if (act == CR_DIE)
+            exit(1);
     }
 }
 
+int get_fd_sockets(int *sockfd[])
+{
+    int sd = 0;
+
+#ifdef SYSTEMD
+    sd = sd_listen_fds(0);
+    if (sd < 0) {
+      fprintf(stderr, "sd_listen_fds(): %s\n", strerror(-sd));
+      exit(1);
+    }
+    if (sd > 0) {
+      int i;
+      *sockfd = malloc(sd * sizeof(*sockfd[0]));
+      for (i = 0; i < sd; i++) {
+        (*sockfd)[i] = SD_LISTEN_FDS_START + i;
+      }
+    }
+#endif
+
+    return sd;
+}
+
 /* Starts listening sockets on specified addresses.
  * IN: addr[], num_addr
  * OUT: *sockfd[]  pointer to newly-allocated array of file descriptors
@@ -63,6 +105,13 @@ int start_listen_sockets(int *sockfd[], struct addrinfo *addr_list)
    struct addrinfo *addr;
    int i, res, one;
    int num_addr = 0;
+   int sd_socks = 0;
+
+   sd_socks = get_fd_sockets(sockfd);
+
+   if (sd_socks > 0) {
+       return sd_socks;
+   }
 
    for (addr = addr_list; addr; addr = addr->ai_next)
        num_addr++;
@@ -80,22 +129,32 @@ int start_listen_sockets(int *sockfd[], struct addrinfo *addr_list)
        saddr = (struct sockaddr_storage*)addr->ai_addr;
 
        (*sockfd)[i] = socket(saddr->ss_family, SOCK_STREAM, 0);
-       check_res_dumpdie((*sockfd)[i], addr, "socket");
+       check_res_dump(CR_DIE, (*sockfd)[i], addr, "socket");
 
        one = 1;
        res = setsockopt((*sockfd)[i], SOL_SOCKET, SO_REUSEADDR, (char*)&one, sizeof(one));
-       check_res_dumpdie(res, addr, "setsockopt(SO_REUSEADDR)");
+       check_res_dump(CR_DIE, res, addr, "setsockopt(SO_REUSEADDR)");
+
+       if (addr->ai_flags & SO_KEEPALIVE) {
+           res = setsockopt((*sockfd)[i], SOL_SOCKET, SO_KEEPALIVE, (char*)&one, sizeof(one));
+           check_res_dump(CR_DIE, res, addr, "setsockopt(SO_KEEPALIVE)");
+       }
 
        if (IP_FREEBIND) {
            res = setsockopt((*sockfd)[i], IPPROTO_IP, IP_FREEBIND, (char*)&one, sizeof(one));
-           check_res_dumpdie(res, addr, "setsockopt(IP_FREEBIND)");
+           check_res_dump(CR_WARN, res, addr, "setsockopt(IP_FREEBIND)");
+           }
+
+       if (addr->ai_addr->sa_family == AF_INET6) {
+           res = setsockopt((*sockfd)[i], IPPROTO_IPV6, IPV6_V6ONLY, (char*)&one, sizeof(one));
+           check_res_dump(CR_WARN, res, addr, "setsockopt(IPV6_V6ONLY)");
        }
 
        res = bind((*sockfd)[i], addr->ai_addr, addr->ai_addrlen);
-       check_res_dumpdie(res, addr, "bind");
+       check_res_dump(CR_DIE, res, addr, "bind");
 
        res = listen ((*sockfd)[i], 50);
-       check_res_dumpdie(res, addr, "listen");
+       check_res_dump(CR_DIE, res, addr, "listen");
 
    }
 
@@ -119,8 +178,53 @@ int bind_peer(int fd, int fd_from)
      * got here */
     res = getpeername(fd_from, from.ai_addr, &from.ai_addrlen);
     CHECK_RES_RETURN(res, "getpeername");
+    
+    /* if the destination is the same machine, there's no need to do bind */
+    struct ifaddrs *ifaddrs_p = NULL, *ifa;
+
+    getifaddrs(&ifaddrs_p);
+
+    for (ifa = ifaddrs_p; ifa != NULL; ifa = ifa->ifa_next)
+    {
+        if (!ifa->ifa_addr)
+            continue;
+        int match = 0;
+        if (from.ai_addr->sa_family == ifa->ifa_addr->sa_family)
+        {
+            int family = ifa->ifa_addr->sa_family;
+            if (family == AF_INET)
+            {
+                struct sockaddr_in *from_addr = (struct sockaddr_in*)from.ai_addr;
+                struct sockaddr_in *ifa_addr = (struct sockaddr_in*)ifa->ifa_addr;
+                if (from_addr->sin_addr.s_addr == ifa_addr->sin_addr.s_addr)
+                    match = 1;
+            }
+            else if (family == AF_INET6)
+            {
+                struct sockaddr_in6 *from_addr = (struct sockaddr_in6*)from.ai_addr;
+                struct sockaddr_in6 *ifa_addr = (struct sockaddr_in6*)ifa->ifa_addr;
+                if (!memcmp(from_addr->sin6_addr.s6_addr, ifa_addr->sin6_addr.s6_addr, 16))
+                    match = 1;
+            }
+        }
+        if (match)  /* the destination is the same as the source, should not create a transparent bind */
+            return 0;
+    }
+
+#ifndef IP_BINDANY /* use IP_TRANSPARENT */
     res = setsockopt(fd, IPPROTO_IP, IP_TRANSPARENT, &trans, sizeof(trans));
     CHECK_RES_DIE(res, "setsockopt");
+#else
+    if (from.ai_addr->sa_family==AF_INET) { /* IPv4 */
+        res = setsockopt(fd, IPPROTO_IP, IP_BINDANY, &trans, sizeof(trans));
+        CHECK_RES_RETURN(res, "setsockopt IP_BINDANY");
+#ifdef IPV6_BINDANY
+    } else { /* IPv6 */
+        res = setsockopt(fd, IPPROTO_IPV6, IPV6_BINDANY, &trans, sizeof(trans));
+        CHECK_RES_RETURN(res, "setsockopt IPV6_BINDANY");
+#endif /* IPV6_BINDANY */
+    }
+#endif /* IP_TRANSPARENT / IP_BINDANY */
     res = bind(fd, from.ai_addr, from.ai_addrlen);
     CHECK_RES_RETURN(res, "bind");
 
@@ -128,20 +232,33 @@ int bind_peer(int fd, int fd_from)
 }
 
 /* Connect to first address that works and returns a file descriptor, or -1 if
- * none work. 
+ * none work.
  * If transparent proxying is on, use fd_from peer address on external address
  * of new file descriptor. */
 int connect_addr(struct connection *cnx, int fd_from)
 {
-    struct addrinfo *a;
+    struct addrinfo *a, from;
+    struct sockaddr_storage ss;
     char buf[NI_MAXHOST];
-    int fd, res;
+    int fd, res, one;
+
+    memset(&from, 0, sizeof(from));
+    from.ai_addr = (struct sockaddr*)&ss;
+    from.ai_addrlen = sizeof(ss);
+
+    res = getpeername(fd_from, from.ai_addr, &from.ai_addrlen);
+    CHECK_RES_RETURN(res, "getpeername");
 
     for (a = cnx->proto->saddr; a; a = a->ai_next) {
-        if (verbose) 
-            fprintf(stderr, "connecting to %s family %d len %d\n", 
+        /* When transparent, make sure both connections use the same address family */
+        if (transparent && a->ai_family != from.ai_addr->sa_family)
+            continue;
+        if (verbose)
+            fprintf(stderr, "connecting to %s family %d len %d\n",
                     sprintaddr(buf, sizeof(buf), a),
                     a->ai_addr->sa_family, a->ai_addrlen);
+
+        /* XXX Needs to match ai_family from fd_from when being transparent! */
         fd = socket(a->ai_family, SOCK_STREAM, 0);
         if (fd == -1) {
             log_message(LOG_ERR, "forward to %s failed:socket: %s\n",
@@ -153,9 +270,15 @@ int connect_addr(struct connection *cnx, int fd_from)
             }
             res = connect(fd, a->ai_addr, a->ai_addrlen);
             if (res == -1) {
-                log_message(LOG_ERR, "forward to %s failed:connect: %s\n", 
+                log_message(LOG_ERR, "forward to %s failed:connect: %s\n",
                             cnx->proto->description, strerror(errno));
+                close(fd);
             } else {
+                if (cnx->proto->keepalive) {
+                    one = 1;
+                    res = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (char*)&one, sizeof(one));
+                    CHECK_RES_RETURN(res, "setsockopt(SO_KEEPALIVE)");
+                }
                 return fd;
             }
         }
@@ -164,20 +287,22 @@ int connect_addr(struct connection *cnx, int fd_from)
 }
 
 /* Store some data to write to the queue later */
-int defer_write(struct queue *q, void* data, int data_size) 
+int defer_write(struct queue *q, void* data, int data_size)
 {
     char *p;
-    if (verbose) 
+    ptrdiff_t data_offset = q->deferred_data - q->begin_deferred_data;
+    if (verbose)
         fprintf(stderr, "**** writing deferred on fd %d\n", q->fd);
 
-    p = realloc(q->begin_deferred_data, q->deferred_data_size + data_size);
+    p = realloc(q->begin_deferred_data, data_offset + q->deferred_data_size + data_size);
     if (!p) {
         perror("realloc");
         exit(1);
     }
 
-    q->deferred_data = q->begin_deferred_data = p;
-    p += q->deferred_data_size;
+    q->begin_deferred_data = p;
+    q->deferred_data = p + data_offset;
+    p += data_offset + q->deferred_data_size;
     q->deferred_data_size += data_size;
     memcpy(p, data, data_size);
 
@@ -231,7 +356,7 @@ void dump_connection(struct connection *cnx)
 }
 
 
-/* 
+/*
  * moves data from one fd to other
  *
  * returns number of bytes copied if success
@@ -299,16 +424,16 @@ char* sprintaddr(char* buf, size_t size, struct addrinfo *a)
    int res;
 
    res = getnameinfo(a->ai_addr, a->ai_addrlen,
-               host, sizeof(host), 
-               serv, sizeof(serv), 
+               host, sizeof(host),
+               serv, sizeof(serv),
                numeric ? NI_NUMERICHOST | NI_NUMERICSERV : 0 );
 
    if (res) {
        log_message(LOG_ERR, "sprintaddr:getnameinfo: %s\n", gai_strerror(res));
        /* Name resolution failed: do it numerically instead */
        res = getnameinfo(a->ai_addr, a->ai_addrlen,
-                         host, sizeof(host), 
-                         serv, sizeof(serv), 
+                         host, sizeof(host),
+                         serv, sizeof(serv),
                          NI_NUMERICHOST | NI_NUMERICSERV);
        /* should not fail but... */
        if (res) {
@@ -323,21 +448,44 @@ char* sprintaddr(char* buf, size_t size, struct addrinfo *a)
    return buf;
 }
 
-/* Turns a hostname and port (or service) into a list of struct addrinfo 
+/* Turns a hostname and port (or service) into a list of struct addrinfo
  * returns 0 on success, -1 otherwise and logs error
- **/
-int resolve_split_name(struct addrinfo **out, const char* host, const char* serv)
+ */
+int resolve_split_name(struct addrinfo **out, const char* ct_host, const char* serv)
 {
    struct addrinfo hint;
+   char *end;
    int res;
+   char* host, *host_base;
 
    memset(&hint, 0, sizeof(hint));
    hint.ai_family = PF_UNSPEC;
    hint.ai_socktype = SOCK_STREAM;
 
+   /* Copy parameter so not to clobber data in libconfig */
+   res = asprintf(&host_base, "%s", ct_host);
+   if (res == -1) {
+       log_message(LOG_ERR, "asprintf: cannot allocate memory");
+       return -1;
+   }
+
+   host = host_base;
+
+   /* If it is a RFC-Compliant IPv6 address ("[1234::12]:443"), remove brackets
+    * around IP address */
+   if (host[0] == '[') {
+       end = strrchr(host, ']');
+       if (!end) {
+           fprintf(stderr, "%s: no closing bracket in IPv6 address?\n", host);
+       }
+       host++; /* skip first bracket */
+       *end = 0; /* remove last bracket */
+   }
+
    res = getaddrinfo(host, serv, &hint, out);
    if (res)
       log_message(LOG_ERR, "%s `%s:%s'\n", gai_strerror(res), host, serv);
+   free(host_base);
    return res;
 }
 
@@ -350,18 +498,17 @@ void resolve_name(struct addrinfo **out, char* fullname)
    char *serv, *host;
    int res;
 
+   /* Find port */
    char *sep = strrchr(fullname, ':');
-
-   if (!sep) /* No separator: parameter is just a port */
-   {
+   if (!sep) { /* No separator: parameter is just a port */
       fprintf(stderr, "%s: names must be fully specified as hostname:port\n", fullname);
       exit(1);
    }
-
-   host = fullname;
    serv = sep+1;
    *sep = 0;
 
+   host = fullname;
+
    res = resolve_split_name(out, host, serv);
    if (res) {
       fprintf(stderr, "%s `%s'\n", gai_strerror(res), fullname);
@@ -394,11 +541,14 @@ void log_connection(struct connection *cnx)
         local[MAX_NAMELENGTH], target[MAX_NAMELENGTH];
     int res;
 
+    if (cnx->proto->log_level < 1)
+        return;
+
     addr.ai_addr = (struct sockaddr*)&ss;
     addr.ai_addrlen = sizeof(ss);
 
     res = getpeername(cnx->q[0].fd, addr.ai_addr, &addr.ai_addrlen);
-    if (res == -1) return; /* Can happen if connection drops before we get here. 
+    if (res == -1) return; /* Can happen if connection drops before we get here.
                                In that case, don't log anything (there is no connection) */
     sprintaddr(peer, sizeof(peer), &addr);
 
@@ -417,7 +567,8 @@ void log_connection(struct connection *cnx)
     if (res == -1) return;
     sprintaddr(local, sizeof(local), &addr);
 
-    log_message(LOG_INFO, "connection from %s to %s forwarded from %s to %s\n",
+    log_message(LOG_INFO, "%s:connection from %s to %s forwarded from %s to %s\n",
+                cnx->proto->description,
                 peer,
                 service,
                 local,
@@ -434,16 +585,19 @@ void log_connection(struct connection *cnx)
 int check_access_rights(int in_socket, const char* service)
 {
 #ifdef LIBWRAP
-    struct sockaddr peeraddr;
-    socklen_t size = sizeof(peeraddr);
+    union {
+        struct sockaddr saddr;
+        struct sockaddr_storage ss;
+    } peer;
+    socklen_t size = sizeof(peer);
     char addr_str[NI_MAXHOST], host[NI_MAXHOST];
     int res;
 
-    res = getpeername(in_socket, &peeraddr, &size);
+    res = getpeername(in_socket, &peer.saddr, &size);
     CHECK_RES_RETURN(res, "getpeername");
 
     /* extract peer address */
-    res = getnameinfo(&peeraddr, size, addr_str, sizeof(addr_str), NULL, 0, NI_NUMERICHOST);
+    res = getnameinfo(&peer.saddr, size, addr_str, sizeof(addr_str), NULL, 0, NI_NUMERICHOST);
     if (res) {
         if (verbose)
             fprintf(stderr, "getnameinfo(NI_NUMERICHOST):%s\n", gai_strerror(res));
@@ -452,7 +606,7 @@ int check_access_rights(int in_socket, const char* service)
     /* extract peer name */
     strcpy(host, STRING_UNKNOWN);
     if (!numeric) {
-        res = getnameinfo(&peeraddr, size, host, sizeof(host), NULL, 0, NI_NAMEREQD);
+        res = getnameinfo(&peer.saddr, size, host, sizeof(host), NULL, 0, NI_NAMEREQD);
         if (res) {
             if (verbose)
                 fprintf(stderr, "getnameinfo(NI_NAMEREQD):%s\n", gai_strerror(res));
@@ -497,17 +651,26 @@ void setup_signals(void)
 
 }
 
-/* Open syslog connection with appropriate banner; 
+/* Open syslog connection with appropriate banner;
  * banner is made up of basename(bin_name)+"[pid]" */
 void setup_syslog(const char* bin_name) {
     char *name1, *name2;
-    int res;
+    int res, fn;
 
     name1 = strdup(bin_name);
     res = asprintf(&name2, "%s[%d]", basename(name1), getpid());
     CHECK_RES_DIE(res, "asprintf");
-    openlog(name2, LOG_CONS, LOG_AUTH);
-    free(name1); 
+
+    for (fn = 0; facilitynames[fn].c_val != -1; fn++)
+        if (strcmp(facilitynames[fn].c_name, facility) == 0)
+            break;
+    if (fn == -1) {
+        fprintf(stderr, "Unknown facility %s\n", facility);
+        exit(1);
+    }
+
+    openlog(name2, LOG_CONS, facilitynames[fn].c_val);
+    free(name1);
     /* Don't free name2, as openlog(3) uses it (at least in glibc) */
 
     log_message(LOG_INFO, "%s %s started\n", server_type, VERSION);
@@ -564,26 +727,47 @@ void set_capabilities(void) {
 }
 
 /* We don't want to run as root -- drop privileges if required */
-void drop_privileges(const char* user_name)
+void drop_privileges(const char* user_name, const char* chroot_path)
 {
     int res;
-    struct passwd *pw = getpwnam(user_name);
-    if (!pw) {
-        fprintf(stderr, "%s: not found\n", user_name);
-        exit(2);
+    struct passwd *pw = NULL;
+
+    if (user_name) {
+        pw = getpwnam(user_name);
+        if (!pw) {
+            fprintf(stderr, "%s: not found\n", user_name);
+            exit(2);
+        }
+        if (verbose)
+            fprintf(stderr, "turning into %s\n", user_name);
     }
-    if (verbose)
-        fprintf(stderr, "turning into %s\n", user_name);
 
-    set_keepcaps(1);
+    if (chroot_path) {
+        if (verbose)
+            fprintf(stderr, "chrooting into %s\n", chroot_path);
 
-    res = setgid(pw->pw_gid);
-    CHECK_RES_DIE(res, "setgid");
-    res = setuid(pw->pw_uid);
-    CHECK_RES_DIE(res, "setuid");
+        res = chroot(chroot_path);
+        CHECK_RES_DIE(res, "chroot");
+    }
 
-    set_capabilities();
-    set_keepcaps(0);
+    if (user_name) {
+        set_keepcaps(1);
+
+        /* remove extraneous groups in case we belong to several extra groups
+         * that may have unwanted rights. If non-root when calling setgroups(),
+         * it fails, which is fine because... we have no unwanted rights
+         * (see POS36-C for security context)
+         * */
+        setgroups(0, NULL);
+
+        res = setgid(pw->pw_gid);
+        CHECK_RES_DIE(res, "setgid");
+        res = setuid(pw->pw_uid);
+        CHECK_RES_DIE(res, "setuid");
+
+        set_capabilities();
+        set_keepcaps(0);
+    }
 }
 
 /* Writes my PID */

common.h

@@ -1,5 +1,5 @@
-#ifndef __COMMON_H_
-#define __COMMON_H_
+#ifndef COMMON_H
+#define COMMON_H
 
 /* FD_SETSIZE is 64 on Cygwin, which is really low. Just redefining it is
  * enough for the macros to adapt (http://support.microsoft.com/kb/111855)
@@ -37,13 +37,14 @@
 
 #define CHECK_RES_DIE(res, str) \
     if (res == -1) {    \
+       fprintf(stderr, "%s:%d:", __FILE__, __LINE__); \
        perror(str);     \
        exit(1);         \
     }
 
 #define CHECK_RES_RETURN(res, str) \
     if (res == -1) {                                    \
-        log_message(LOG_CRIT, "%s:%d:%s\n", str, errno, strerror(errno));  \
+        log_message(LOG_CRIT, "%s:%d:%s:%d:%s\n", __FILE__, __LINE__, str, errno, strerror(errno));  \
         return res;                                     \
     } 
 
@@ -102,7 +103,7 @@ void log_connection(struct connection *cnx);
 int check_access_rights(int in_socket, const char* service);
 void setup_signals(void);
 void setup_syslog(const char* bin_name);
-void drop_privileges(const char* user_name);
+void drop_privileges(const char* user_name, const char* chroot_path);
 void write_pid_file(const char* pidfile);
 void log_message(int type, char* msg, ...);
 void dump_connection(struct connection *cnx);
@@ -118,7 +119,7 @@ extern int probing_timeout, verbose, inetd, foreground,
 extern struct sockaddr_storage addr_ssl, addr_ssh, addr_openvpn;
 extern struct addrinfo *addr_listen;
 extern const char* USAGE_STRING;
-extern const char* user_name, *pid_file;
+extern const char* user_name, *pid_file, *chroot_path, *facility;
 extern const char* server_type;
 
 /* sslh-fork.c */

example.cfg

@@ -11,42 +11,93 @@ transparent: false;
 timeout: 2;
 user: "nobody";
 pidfile: "/var/run/sslh.pid";
+chroot: "/var/empty";
 
+# Specify which syslog facility to use (names for your
+# system are usually defined in /usr/include/*/sys/syslog.h
+# or equivalent)
+# Default is "auth"
+syslog_facility: "auth"; 
 
 # List of interfaces on which we should listen
+# Options:
 listen:
 (
     { host: "thelonious"; port: "443"; },
-    { host: "thelonious"; port: "8080"; }
+    { host: "thelonious"; port: "8080"; keepalive: true; }
 );
 
 # List of protocols
 #
 # Each protocol entry consists of:
-#   name: name of the protocol
+#   name: name of the probe. These are listed on the command
+#   line (ssh -?), plus 'regex' and 'timeout'.
+
 #   service: (optional) libwrap service name (see hosts_access(5))
-#   host: host name to connect that protocol
-#   port: port number to connect that protocol
-#   probe: "builtin" or a list of regular expressions
-#          (can be left out, e.g. to use with on-timeout)
+#   host, port: where to connect when this probe succeeds
+#   log_level:  0 to turn off logging
+#               1 to log each incoming connection
+#   keepalive:  Should TCP keepalive be on or off for that
+#               connection (default is off)
+#   fork: Should a new process be forked for this protocol?
+#         (only useful for sslh-select)
+#
+#  Probe-specific options:
+#       tls:
+#               sni_hostnames:  list of FQDN for that target
+#               alpn_protocols: list of ALPN protocols for that target, see:
+#               https://www.iana.org/assignments/tls-extensiontype-values/tls-extensiontype-values.xhtml#alpn-protocol-ids
+#
+#               if both sni_hostnames AND alpn_protocols are specified, both must match
+#               if neither are set, it is just checked whether this is the TLS protocol or not
+#       regex:
+#               regex_patterns: list of patterns to match for
+#               that target.
 #   
 # sslh will try each probe in order they are declared, and
 # connect to the first that matches.
-
+#
+# You can specify several of 'regex' and 'tls'.
+ 
 protocols:
 (
-     { name: "ssh"; service: "ssh"; host: "localhost"; port: "22"; probe: "builtin"; },
-     { name: "openvpn"; host: "localhost"; port: "1194"; probe: [ "^\x00[\x0D-\xFF]$", "^\x00[\x0D-\xFF]\x38" ]; },
-     { name: "xmpp"; host: "localhost"; port: "5222"; probe: [ "jabber" ]; },
-     { name: "http"; host: "localhost"; port: "80"; probe: "builtin"; },
-     { name: "ssl"; host: "localhost"; port: "443"; probe: [ "" ]; },
+     { name: "ssh"; service: "ssh"; host: "localhost"; port: "22"; keepalive: true; fork: true; },
+     { name: "http"; host: "localhost"; port: "80"; },
+
+# match BOTH ALPN/SNI
+     { name: "tls"; host: "localhost"; port: "5223"; alpn_protocols: [ "xmpp-client" ]; sni_hostnames: [ "im.somethingelse.net" ]; log_level: 0;},
+
+# just match ALPN
+     { name: "tls"; host: "localhost"; port: "443"; alpn_protocols: [ "h2", "http/1.1", "spdy/1", "spdy/2", "spdy/3" ]; log_level: 0; },
+     { name: "tls"; host: "localhost"; port: "xmpp-client"; alpn_protocols: [ "xmpp-client" ];  log_level: 0;},
+
+# just match SNI
+     { name: "tls"; host: "localhost"; port: "993"; sni_hostnames: [ "mail.rutschle.net", "mail.englishintoulouse.com" ]; log_level: 0; },
+     { name: "tls"; host: "localhost"; port: "xmpp-client"; sni_hostnames: [ "im.rutschle.net", "im.englishintoulouse.com" ];  log_level: 0;},
+
+# Let's Encrypt (tls-sni-* challenges)
+     { name: "tls"; host: "localhost"; port: "letsencrypt-client"; sni_hostnames: [ "*.*.acme.invalid" ];  log_level: 0;},
+
+# catch anything else TLS
+     { name: "tls"; host: "localhost"; port: "443"; },
+
+# Regex examples -- better use the built-in probes for real-world use!
+# OpenVPN
+     { name: "regex"; host: "localhost"; port: "1194"; regex_patterns: [ "^\x00[\x0D-\xFF]$", "^\x00[\x0D-\xFF]\x38" ]; },
+# Jabber
+     { name: "regex"; host: "localhost"; port: "5222"; regex_patterns: [ "jabber" ]; },
+    
+# Catch-all
+     { name: "regex"; host: "localhost"; port: "443"; regex_patterns: [ "" ]; },
+
+# Where to connect in case of timeout (defaults to ssh)
      { name: "timeout"; service: "daytime"; host: "localhost"; port: "daytime"; }
 );
 
 # Optionally, specify to which protocol to connect in case
 # of timeout (defaults to "ssh").
-# You can timeout to any arbitrary address by setting a
-# protocol with no probe, as is the case with this example.
+# You can timeout to any arbitrary address by setting an
+# entry in 'protocols' named "timeout".
 # This enables you to set a tcpd service name for this
 # protocol too.
 on-timeout: "timeout";

genver.sh

@@ -1,4 +1,4 @@
-#! /bin/bash
+#! /bin/sh
 
 if [ ${#} -eq 1 ] && [ "x$1" = "x-r" ]; then
 	# release text only
@@ -10,10 +10,19 @@ fi
 if ! `(git status | grep -q "On branch") 2> /dev/null`; then
         # If we don't have git, we can't work out what
         # version this is. It must have been downloaded as a
-        # zip file. Github creates the zip file with all
-        # files dated from the last change: use the
-        # Makefile's modification time as a release number
-	release=zip-`stat -c "%y" Makefile | sed 's/ .*//'`
+        # zip file. 
+        
+        # If downloaded from the release page, the directory
+        # has the version number.
+        release=`pwd | sed s/.*sslh-// | grep "[[:digit:]]"`
+        
+        if [ "x$release" = "x" ]; then
+            # If downloaded from the head, Github creates the
+            # zip file with all files dated from the last
+            # change: use the Makefile's modification time as a
+            # release number
+            release=head-`perl -MPOSIX -e 'print strftime "%Y-%m-%d",localtime((stat "Makefile")[9])'`
+        fi
 fi
 
 if head=`git rev-parse --verify HEAD 2>/dev/null`; then
@@ -31,8 +40,8 @@ fi
 
 
 if [ $QUIET -ne 1 ]; then
-	printf "#ifndef _VERSION_H_ \n"
-	printf "#define _VERSION_H_ \n\n"
+	printf "#ifndef VERSION_H \n"
+	printf "#define VERSION_H \n\n"
 	printf "#define VERSION \"$release\"\n"
 	printf "#endif\n"
 else

probe.c

@@ -1,7 +1,7 @@
 /*
 # probe.c: Code for probing protocols
 #
-# Copyright (C) 2007-2012  Yves Rutschle
+# Copyright (C) 2007-2015  Yves Rutschle
 # 
 # This program is free software; you can redistribute it
 # and/or modify it under the terms of the GNU General Public
@@ -21,7 +21,13 @@
 
 #define _GNU_SOURCE
 #include <stdio.h>
+#ifdef ENABLE_REGEX
+#ifdef LIBPCRE
+#include <pcreposix.h>
+#else
 #include <regex.h>
+#endif
+#endif
 #include <ctype.h>
 #include "probe.h"
 
@@ -33,20 +39,22 @@ static int is_tinc_protocol(const char *p, int len, struct proto*);
 static int is_xmpp_protocol(const char *p, int len, struct proto*);
 static int is_http_protocol(const char *p, int len, struct proto*);
 static int is_tls_protocol(const char *p, int len, struct proto*);
+static int is_adb_protocol(const char *p, int len, struct proto*);
 static int is_true(const char *p, int len, struct proto* proto) { return 1; }
 
 /* Table of protocols that have a built-in probe
  */
 static struct proto builtins[] = {
-    /* description   service  saddr   probe  */
-    { "ssh",         "sshd",   NULL,   is_ssh_protocol},
-    { "openvpn",     NULL,     NULL,   is_openvpn_protocol },
-    { "tinc",        NULL,     NULL,   is_tinc_protocol },
-    { "xmpp",        NULL,     NULL,   is_xmpp_protocol },
-    { "http",        NULL,     NULL,   is_http_protocol },
-    { "ssl",         NULL,     NULL,   is_tls_protocol },
-    { "tls",         NULL,     NULL,   is_tls_protocol },
-    { "anyprot",     NULL,     NULL,   is_true }
+    /* description   service  saddr  log_level  keepalive  fork  probe  */
+    { "ssh",         "sshd",   NULL,  1,        0,         1,    is_ssh_protocol},
+    { "openvpn",     NULL,     NULL,  1,        0,         1,    is_openvpn_protocol },
+    { "tinc",        NULL,     NULL,  1,        0,         1,    is_tinc_protocol },
+    { "xmpp",        NULL,     NULL,  1,        0,         0,    is_xmpp_protocol },
+    { "http",        NULL,     NULL,  1,        0,         0,    is_http_protocol },
+    { "ssl",         NULL,     NULL,  1,        0,         0,    is_tls_protocol },
+    { "tls",         NULL,     NULL,  1,        0,         0,    is_tls_protocol },
+    { "adb",         NULL,     NULL,  1,        0,         0,    is_adb_protocol },
+    { "anyprot",     NULL,     NULL,  1,        0,         0,    is_true }
 };
 
 static struct proto *protocols;
@@ -99,25 +107,25 @@ void hexdump(const char *mem, unsigned int len)
     {
         /* print offset */
         if(i % HEXDUMP_COLS == 0)
-            printf("0x%06x: ", i);
+            fprintf(stderr, "0x%06x: ", i);
 
         /* print hex data */
         if(i < len)
-            printf("%02x ", 0xFF & mem[i]);
+            fprintf(stderr, "%02x ", 0xFF & mem[i]);
         else /* end of block, just aligning for ASCII dump */
-            printf("   ");
+            fprintf(stderr, "   ");
 
         /* print ASCII dump */
         if(i % HEXDUMP_COLS == (HEXDUMP_COLS - 1)) {
             for(j = i - (HEXDUMP_COLS - 1); j <= i; j++) {
                 if(j >= len) /* end of block, not really printing */
-                    putchar(' ');
+                    fputc(' ', stderr);
                 else if(isprint(mem[j])) /* printable char */
-                    putchar(0xFF & mem[j]);        
+                    fputc(0xFF & mem[j], stderr);
                 else /* other char */
-                    putchar('.');
+                    fputc('.', stderr);
             }
-            putchar('\n');
+            fputc('\n', stderr);
         }
     }
 }
@@ -153,7 +161,8 @@ static int is_openvpn_protocol (const char*p,int len, struct proto *proto)
 }
 
 /* Is the buffer the beginning of a tinc connections?
- * (protocol is undocumented, but starts with "0 " in 1.0.15)
+ * Protocol is documented here: http://www.tinc-vpn.org/documentation/tinc.pdf
+ * First connection starts with "0 " in 1.0.15)
  * */
 static int is_tinc_protocol( const char *p, int len, struct proto *proto)
 {
@@ -169,7 +178,10 @@ static int is_tinc_protocol( const char *p, int len, struct proto *proto)
  * */
 static int is_xmpp_protocol( const char *p, int len, struct proto *proto)
 {
-    if (len < 6)
+    /* sometimes the word 'jabber' shows up late in the initial string,
+       sometimes after a newline. this makes sure we snarf the entire preamble
+       and detect it. (fixed for adium/pidgin) */
+    if (len < 50)
         return PROBE_AGAIN;
 
     return memmem(p, len, "jabber", 6) ? 1 : 0;
@@ -209,27 +221,111 @@ static int is_http_protocol(const char *p, int len, struct proto *proto)
     return PROBE_NEXT;
 }
 
+static int is_sni_alpn_protocol(const char *p, int len, struct proto *proto)
+{
+    int valid_tls;
+
+    valid_tls = parse_tls_header(proto->data, p, len);
+
+    if(valid_tls < 0)
+        return -1 == valid_tls ? PROBE_AGAIN : PROBE_NEXT;
+
+    /* There *was* a valid match */
+    return PROBE_MATCH;
+}
+
 static int is_tls_protocol(const char *p, int len, struct proto *proto)
 {
-    if (len < 3)
+    if (len < 6)
         return PROBE_AGAIN;
 
-    /* TLS packet starts with a record "Hello" (0x16), followed by version
-     * (0x03 0x00-0x03) (RFC6101 A.1)
-     * This means we reject SSLv2 and lower, which is actually a good thing (RFC6176)
+    /* TLS packet starts with a record "Hello" (0x16), followed by the number of
+     * the highest version of SSL/TLS supported.
+     *
+     * A SSLv2 record header contains a two or three byte length code. If the
+     * most significant bit is set in the first byte of the record length code
+     * then the record has no padding and the total header length will be 2
+     * bytes,  otherwise the record has padding and the total header length will
+     * be 3 bytes. Next, a 1 char sized client-hello (0x01) is expected,
+     * followed by a 2 char sized version that indicates the highest version of
+     * TLS/SSL supported by the sender. [SSL2] Hickman, Kipp, "The SSL Protocol"
+     *
+     * We're checking the highest version of TLS/SSL supported against
+     * (0x03 0x00-0x03) (RFC6101 A.1). This means we reject the usage of SSLv2
+     * and lower, which is actually a good thing (RFC6176).
      */
-    return p[0] == 0x16 && p[1] == 0x03 && ( p[2] >= 0 && p[2] <= 0x03);
+    if (p[0] == 0x16) // TLS client-hello
+        return p[1] == 0x03 && ( p[2] >= 0 && p[2] <= 0x03);
+    if ((p[0] & 0x80) != 0) // SSLv2 client-hello, no padding
+        return p[2] == 0x01 && p[3] == 0x03 && ( p[4] >= 0 && p[4] <= 0x03);
+    else // SSLv2 client-hello, padded
+        return p[3] == 0x01 && p[4] == 0x03 && ( p[5] >= 0 && p[5] <= 0x03);
+}
+
+static int probe_adb_cnxn_message(const char *p)
+{
+    /* The initial ADB host->device packet has a command type of CNXN, and a
+     * data payload starting with "host:".  Note that current versions of the
+     * client hardcode "host::" (with empty serialno and banner fields) but
+     * other clients may populate those fields.
+     */
+    return !memcmp(&p[0], "CNXN", 4) && !memcmp(&p[24], "host:", 5);
+}
+
+static int is_adb_protocol(const char *p, int len, struct proto *proto)
+{
+    /* amessage.data_length is not being checked, under the assumption that
+     * a packet >= 30 bytes will have "something" in the payload field.
+     *
+     * 24 bytes for the message header and 5 bytes for the "host:" tag.
+     *
+     * ADB protocol:
+     * https://android.googlesource.com/platform/system/adb/+/master/protocol.txt
+     */
+    static const unsigned int min_data_packet_size = 30;
+
+    if (len < min_data_packet_size)
+        return PROBE_AGAIN;
+
+    if (probe_adb_cnxn_message(&p[0]) == PROBE_MATCH)
+        return PROBE_MATCH;
+
+    /* In ADB v26.0.0 rc1-4321094, the initial host->device packet sends an
+     * empty message before sending the CNXN command type. This was an
+     * unintended side effect introduced in
+     * https://android-review.googlesource.com/c/342653, and will be reverted for
+     * a future release.
+     */
+    static const unsigned char empty_message[] = {
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff
+    };
+
+    if (len < min_data_packet_size + sizeof(empty_message))
+        return PROBE_AGAIN;
+
+    if (memcmp(&p[0], empty_message, sizeof(empty_message)))
+        return PROBE_NEXT;
+
+    return probe_adb_cnxn_message(&p[sizeof(empty_message)]);
 }
 
 static int regex_probe(const char *p, int len, struct proto *proto)
 {
+#ifdef ENABLE_REGEX
     regex_t **probe = proto->data;
     regmatch_t pos = { 0, len };
 
     for (; *probe && regexec(*probe, p, 0, &pos, REG_STARTEND); probe++)
         /* try them all */;
 
-    return (probe != NULL);
+    return (*probe != NULL);
+#else
+    /* Should never happen as we check when loading config file */
+    fprintf(stderr, "FATAL: regex probe called but not built in\n");
+    exit(5);
+#endif
 }
 
 /* 
@@ -250,6 +346,13 @@ int probe_client_protocol(struct connection *cnx)
      * happens, we just connect to the default protocol so the caller of this
      * function does not have to deal with a specific  failure condition (the
      * connection will just fail later normally). */
+
+    /* Dump hex values of the packet */
+    if (verbose>1) {
+        fprintf(stderr, "hexdump of incoming packet:\n");
+        hexdump(buffer, n);
+    }
+
     if (n > 0) {
         int res = PROBE_NEXT;
 
@@ -305,6 +408,15 @@ T_PROBE* get_probe(const char* description) {
     if (!strcmp(description, "regex"))
         return regex_probe;
 
+    /* Special case of "sni/alpn" probe for same reason as above*/
+    if (!strcmp(description, "sni_alpn"))
+        return is_sni_alpn_protocol;
+
+    /* Special case of "timeout" is allowed as a probe name in the
+     * configuration file even though it's not really a probe */
+    if (!strcmp(description, "timeout"))
+        return is_true;
+
     return NULL;
 }
 

probe.h

@@ -1,9 +1,10 @@
 /* API for probe.c */
 
-#ifndef __PROBE_H_
-#define __PROBE_H_
+#ifndef PROBE_H
+#define PROBE_H
 
 #include "common.h"
+#include "tls.h"
 
 typedef enum {
     PROBE_NEXT,  /* Enough data, probe failed -- it's some other protocol */
@@ -19,11 +20,17 @@ struct proto {
     const char* description;  /* a string that says what it is (for logging and command-line parsing) */
     const char* service;      /* service name to do libwrap checks */
     struct addrinfo *saddr; /* list of addresses to try and switch that protocol */
+    int log_level;  /* 0: No logging of connection
+                     * 1: Log incoming connection
+                     */
+    int keepalive; /* 0: No keepalive ; 1: Set Keepalive for this connection */
+    int fork; /* 0: Connection can run within shared process ; 1: Separate process required for this connection */
 
     /* function to probe that protocol; parameters are buffer and length
      * containing the data to probe, and a pointer to the protocol structure */
     T_PROBE* probe;
-    void* data;     /* opaque pointer ; used to pass list of regex to regex probe */
+    /* opaque pointer ; used to pass list of regex to regex probe, or TLSProtocol struct to sni/alpn probe */
+    void* data;
     struct proto *next; /* pointer to next protocol in list, NULL if last */
 };
 

scripts/etc.default.sslh

@@ -1,5 +0,0 @@
-LISTEN=ifname:443
-SSH=localhost:22
-SSL=localhost:443
-USER=nobody
-PID=/var/run/sslh.pid

scripts/etc.init.d.sslh

@@ -27,7 +27,7 @@ DAEMON=$PREFIX/sbin/sslh
 start()
 {
         echo "Start services: sslh"
-        $DAEMON --user ${USER} --pidfile ${PID} --listen ${LISTEN} --ssh ${SSH} --ssl ${SSL}
+        $DAEMON -F/etc/sslh.cfg
         logger -t ${tag} -p ${facility} -i 'Started sslh'
 }
 

scripts/fail2ban/jail.conf

@@ -0,0 +1,9 @@
+# Add the following to your fail2ban jail.conf
+# In Debian you'd append it to /etc/fail2ban/jail.local
+
+[sslh-ssh]
+enabled = true
+filter = sslh-ssh
+action = iptables-multiport[name=sslh,port="443"]
+logpath = /var/log/messages
+maxretry = 5

scripts/fail2ban/sslh-ssh.conf

@@ -0,0 +1,25 @@
+# Add the following to you fail2ban configuration file
+# In Debian it'd go in /etc/fail2ban/filter.d/sslh-ssh.conf
+
+
+# Fail2Ban filter for sslh demultiplexed ssh
+#
+# Doesn't (and cannot) detect auth errors,
+# but many connection attempts from the same
+# origin is reason enough to block.
+#
+# Verion: 2014-03-28
+
+[INCLUDES]
+
+# no includes
+
+[Definition]
+
+failregex = ^.+ sslh\[.+\]: connection from <HOST>:.+ to .+ forwarded
+from .+ to .+:ssh\s*$
+
+ignoreregex =
+
+# Author: Evert Mouw <post@evert.net>
+

scripts/systemd.sslh.service

@@ -6,6 +6,22 @@ After=network.target
 EnvironmentFile=/etc/conf.d/sslh
 ExecStart=/usr/bin/sslh --foreground $DAEMON_OPTS
 KillMode=process
+#Hardening
+PrivateTmp=true
+CapabilityBoundingSet=CAP_SETGID CAP_SETUID CAP_NET_BIND_SERVICE
+AmbientCapabilities=CAP_NET_BIND_SERVICE
+SecureBits=noroot-locked
+ProtectSystem=strict
+ProtectHome=true
+ProtectKernelModules=true
+ProtectKernelTunables=true
+ProtectControlGroups=true
+MountFlags=private
+NoNewPrivileges=true
+PrivateDevices=true
+RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX
+MemoryDenyWriteExecute=true
+DynamicUser=true
 
 [Install]
 WantedBy=multi-user.target

sslh-fork.c

@@ -94,6 +94,8 @@ void start_shoveler(int in_socket)
        } else {
            /* Timed out: it's necessarily SSH */
            cnx.proto = timeout_protocol();
+           if (verbose) 
+               log_message(LOG_INFO, "timed out, connect to %s\n", cnx.proto->description);
            break;
        }
    }
@@ -146,8 +148,13 @@ void main_loop(int listen_sockets[], int num_addr_listen)
 
     /* Start one process for each listening address */
     for (i = 0; i < num_addr_listen; i++) {
-        if (!(listener_pid[i] = fork())) {
-
+        listener_pid[i] = fork();
+        switch(listener_pid[i]) {
+        // Log if fork() fails for some reason
+        case -1: log_message(LOG_ERR, "fork failed: err %d: %s\n", errno, strerror(errno));
+                 break;
+        // We're in the child, we have work to do 
+        case 0:
             /* Listening process just accepts a connection, forks, and goes
              * back to listening */
             while (1)
@@ -155,15 +162,26 @@ void main_loop(int listen_sockets[], int num_addr_listen)
                 in_socket = accept(listen_sockets[i], 0, 0);
                 if (verbose) fprintf(stderr, "accepted fd %d\n", in_socket);
 
-                if (!fork())
-                {
+                switch(fork()) {
+                case -1: log_message(LOG_ERR, "fork failed: err %d: %s\n", errno, strerror(errno));
+                         break;
+
+                /* In child process */
+                case 0:
                     for (i = 0; i < num_addr_listen; ++i)
                         close(listen_sockets[i]);
                     start_shoveler(in_socket);
                     exit(0);
+
+                /* In parent process */
+                default: break;
                 }
                 close(in_socket);
             }
+	    break;
+	// We're in the parent, we don't need to do anything
+	default:
+	    break;
         }
     }
 

sslh-main.c

@@ -2,7 +2,7 @@
 # main: processing of config file, command line options and start the main
 # loop.
 #
-# Copyright (C) 2007-2012  Yves Rutschle
+# Copyright (C) 2007-2016  Yves Rutschle
 # 
 # This program is free software; you can redistribute it
 # and/or modify it under the terms of the GNU General Public
@@ -25,7 +25,13 @@
 #ifdef LIBCONFIG
 #include <libconfig.h>
 #endif
+#ifdef ENABLE_REGEX
+#ifdef LIBPCRE
+#include <pcreposix.h>
+#else
 #include <regex.h>
+#endif
+#endif
 
 #include "common.h"
 #include "probe.h"
@@ -33,20 +39,22 @@
 const char* USAGE_STRING =
 "sslh " VERSION "\n" \
 "usage:\n" \
-"\tsslh  [-v] [-i] [-V] [-f] [-n] [-F <file>]\n"
-"\t[-t <timeout>] [-P <pidfile>] -u <username> -p <add> [-p <addr> ...] \n" \
+"\tsslh  [-v] [-i] [-V] [-f] [-n] [--transparent] [-F<file>]\n"
+"\t[-t <timeout>] [-P <pidfile>] [-u <username>] [-C <chroot>] -p <add> [-p <addr> ...] \n" \
 "%s\n\n" /* Dynamically built list of builtin protocols */  \
 "\t[--on-timeout <addr>]\n" \
 "-v: verbose\n" \
 "-V: version\n" \
 "-f: foreground\n" \
 "-n: numeric output\n" \
-"-F: use configuration file\n" \
+"-u: specify under which user to run\n" \
+"-C: specify under which chroot path to run\n" \
+"--transparent: behave as a transparent proxy\n" \
+"-F: use configuration file (warning: no space between -F and file name!)\n" \
 "--on-timeout: connect to specified address upon timeout (default: ssh address)\n" \
 "-t: seconds to wait before connecting to --on-timeout address.\n" \
 "-p: address and port to listen on.\n    Can be used several times to bind to several addresses.\n" \
 "--[ssh,ssl,...]: where to connect connections from corresponding protocol.\n" \
-"-F: specify a configuration file\n" \
 "-P: PID file.\n" \
 "-i: Run as a inetd service.\n" \
 "";
@@ -62,8 +70,9 @@ static struct option const_options[] = {
     { "numeric",    no_argument,            &numeric,       1 },
     { "verbose",    no_argument,            &verbose,       1 },
     { "user",       required_argument,      0,              'u' },
-    { "config",     required_argument,      0,              'F' },
+    { "config",     optional_argument,      0,              'F' },
     { "pidfile",    required_argument,      0,              'P' },
+    { "chroot",     required_argument,      0,              'C' },
     { "timeout",    required_argument,      0,              't' },
     { "on-timeout", required_argument,      0,              OPT_ONTIMEOUT },
     { "listen",     required_argument,      0,              'p' },
@@ -71,7 +80,7 @@ static struct option const_options[] = {
 };
 static struct option* all_options;
 static struct proto* builtins;
-static const char *optstr = "vt:T:p:VP:F:";
+static const char *optstr = "vt:T:p:VP:C:F::";
 
 
 
@@ -116,16 +125,22 @@ static void printsettings(void)
     
     for (p = get_first_protocol(); p; p = p->next) {
         fprintf(stderr,
-                "%s addr: %s. libwrap service: %s family %d %d\n", 
+                "%s addr: %s. libwrap service: %s log_level: %d family %d %d [%s] [%s]\n",
                 p->description, 
                 sprintaddr(buf, sizeof(buf), p->saddr), 
                 p->service,
+                p->log_level,
                 p->saddr->ai_family,
-                p->saddr->ai_addr->sa_family);
+                p->saddr->ai_addr->sa_family,
+                p->keepalive ? "keepalive" : "",
+                p->fork ? "fork" : "");
     }
     fprintf(stderr, "listening on:\n");
     for (a = addr_listen; a; a = a->ai_next) {
-        fprintf(stderr, "\t%s\n", sprintaddr(buf, sizeof(buf), a));
+        fprintf(stderr, 
+                "\t%s\t[%s]\n", 
+                sprintaddr(buf, sizeof(buf), a), 
+                a->ai_flags & SO_KEEPALIVE ? "keepalive" : "");
     }
     fprintf(stderr, "timeout: %d\non-timeout: %s\n", probing_timeout,
             timeout_protocol()->description);
@@ -139,7 +154,7 @@ static void printsettings(void)
 static int config_listen(config_t *config, struct addrinfo **listen) 
 {
     config_setting_t *setting, *addr;
-    int len, i;
+    int len, i, keepalive;
     const char *hostname, *port;
 
     setting = config_lookup(config, "listen");
@@ -155,12 +170,20 @@ static int config_listen(config_t *config, struct addrinfo **listen)
                 return -1;
             }
 
+            keepalive = 0;
+            config_setting_lookup_bool(addr, "keepalive", &keepalive);
+
             resolve_split_name(listen, hostname, port);
 
             /* getaddrinfo returned a list of addresses corresponding to the
              * specification; move the pointer to the end of that list before
-             * processing the next specification */
-            for (; *listen; listen = &((*listen)->ai_next));
+             * processing the next specification, while setting flags for
+             * start_listen_sockets() through ai_flags (which is not meant for
+             * that, but is only used as hint in getaddrinfo, so it's OK) */
+            for (; *listen; listen = &((*listen)->ai_next)) {
+                if (keepalive)
+                    (*listen)->ai_flags = SO_KEEPALIVE;
+            }
         }
     }
 
@@ -173,6 +196,7 @@ static int config_listen(config_t *config, struct addrinfo **listen)
 #ifdef LIBCONFIG
 static void setup_regex_probe(struct proto *p, config_setting_t* probes)
 {
+#ifdef ENABLE_REGEX
     int num_probes, errsize, i, res;
     char *err;
     const char * expr;
@@ -191,7 +215,7 @@ static void setup_regex_probe(struct proto *p, config_setting_t* probes)
     for (i = 0; i < num_probes; i++) {
         probe_list[i] = malloc(sizeof(*(probe_list[i])));
         expr = config_setting_get_string_elem(probes, i);
-        res = regcomp(probe_list[i], expr, 0);
+        res = regcomp(probe_list[i], expr, REG_EXTENDED);
         if (res) {
             err = malloc(errsize = regerror(res, probe_list[i], NULL, 0));
             regerror(res, probe_list[i], err, errsize);
@@ -200,6 +224,61 @@ static void setup_regex_probe(struct proto *p, config_setting_t* probes)
             exit(1);
         }
     }
+#else
+    fprintf(stderr, "line %d: regex probe specified but not compiled in\n", config_setting_source_line(probes));
+    exit(5);
+#endif
+}
+#endif
+
+#ifdef LIBCONFIG
+static void setup_sni_alpn_list(struct proto *p, config_setting_t* config_items, const char* name, int alpn)
+{
+    int num_probes, i, max_server_name_len, server_name_len;
+    const char * config_item;
+    char** sni_hostname_list;
+
+    num_probes = config_setting_length(config_items);
+    if (!num_probes) {
+        fprintf(stderr, "%s: no %s specified\n", p->description, name);
+        return;
+    }
+
+    max_server_name_len = 0;
+    for (i = 0; i < num_probes; i++) {
+        server_name_len = strlen(config_setting_get_string_elem(config_items, i));
+        if(server_name_len > max_server_name_len)
+            max_server_name_len = server_name_len;
+    }
+
+    sni_hostname_list = calloc(num_probes + 1, ++max_server_name_len);
+
+    for (i = 0; i < num_probes; i++) {
+        config_item = config_setting_get_string_elem(config_items, i);
+        sni_hostname_list[i] = malloc(max_server_name_len);
+        strcpy (sni_hostname_list[i], config_item);
+        if(verbose) fprintf(stderr, "%s: %s[%d]: %s\n", p->description, name, i, sni_hostname_list[i]);
+    }
+
+    p->data = (void*)tls_data_set_list(p->data, alpn, sni_hostname_list);
+}
+
+static void setup_sni_alpn(struct proto *p, config_setting_t* prot)
+{
+    config_setting_t *sni_hostnames, *alpn_protocols;
+
+    p->data = (void*)new_tls_data();
+    sni_hostnames = config_setting_get_member(prot, "sni_hostnames");
+    alpn_protocols = config_setting_get_member(prot, "alpn_protocols");
+
+    if(sni_hostnames && config_setting_is_array(sni_hostnames)) {
+        p->probe = get_probe("sni_alpn");
+        setup_sni_alpn_list(p, sni_hostnames, "sni_hostnames", 0);
+    }
+    if(alpn_protocols && config_setting_is_array(alpn_protocols)) {
+        p->probe = get_probe("sni_alpn");
+        setup_sni_alpn_list(p, alpn_protocols, "alpn_protocols", 1);
+    }
 }
 #endif
 
@@ -209,7 +288,7 @@ static void setup_regex_probe(struct proto *p, config_setting_t* probes)
 #ifdef LIBCONFIG
 static int config_protocols(config_t *config, struct proto **prots)
 {
-    config_setting_t *setting, *prot, *probes;
+    config_setting_t *setting, *prot, *patterns;
     const char *hostname, *port, *name;
     int i, num_prots;
     struct proto *p, *prev = NULL;
@@ -230,33 +309,40 @@ static int config_protocols(config_t *config, struct proto **prots)
                 )) {
                 p->description = name;
                 config_setting_lookup_string(prot, "service", &(p->service));
+                config_setting_lookup_bool(prot, "keepalive", &p->keepalive);
+                config_setting_lookup_bool(prot, "fork", &p->fork);
 
-                resolve_split_name(&(p->saddr), hostname, port);
+                if (config_setting_lookup_int(prot, "log_level", &p->log_level) == CONFIG_FALSE) {
+                    p->log_level = 1;
+                }
 
+                if (resolve_split_name(&(p->saddr), hostname, port)) {
+                    fprintf(stderr, "line %d: cannot resolve %s:%s\n", config_setting_source_line(prot), hostname, port);
+                    exit(1);
+                }
 
-                probes = config_setting_get_member(prot, "probe");
-                if (probes) {
-                    if (config_setting_is_array(probes)) {
-                        /* If 'probe' is an array, setup a regex probe using the
-                         * array of strings as pattern */
+                p->probe = get_probe(name);
+                if (!p->probe || !strcmp(name, "sni_alpn")) {
+                    fprintf(stderr, "line %d: %s: probe unknown\n", config_setting_source_line(prot), name);
+                    exit(1);
+                }
 
-                        setup_regex_probe(p, probes);
-
-                    } else {
-                        /* if 'probe' is 'builtin', set the probe to the
-                         * appropriate builtin protocol */
-                        if (!strcmp(config_setting_get_string(probes), "builtin")) {
-                            p->probe = get_probe(name);
-                            if (!p->probe) {
-                                fprintf(stderr, "%s: no builtin probe for this protocol\n", name);
-                                exit(1);
-                            }
-                        } else {
-                            fprintf(stderr, "%s: illegal probe name\n", name);
-                            exit(1);
-                        }
+                /* Probe-specific options: regex patterns */
+                if (!strcmp(name, "regex")) {
+                    patterns = config_setting_get_member(prot, "regex_patterns");
+                    if (patterns && config_setting_is_array(patterns)) {
+                        setup_regex_probe(p, patterns);
                     }
                 }
+
+                /* Probe-specific options: SNI/ALPN */
+                if (!strcmp(name, "tls")) {
+                    setup_sni_alpn(p, prot);
+                }
+
+            } else {
+                fprintf(stderr, "line %d: Illegal protocol description (missing name, host or port)\n", config_setting_source_line(prot));
+                exit(1);
             }
         }
     }
@@ -269,6 +355,7 @@ static int config_protocols(config_t *config, struct proto **prots)
  * in: *filename
  * out: *listen, a newly-allocated linked list of listen addrinfo
  *      *prots, a newly-allocated linked list of protocols
+ *      1 on error, 0 on success
  */
 #ifdef LIBCONFIG
 static int config_parse(char *filename, struct addrinfo **listen, struct proto **prots)
@@ -279,14 +366,26 @@ static int config_parse(char *filename, struct addrinfo **listen, struct proto *
 
     config_init(&config);
     if (config_read_file(&config, filename) == CONFIG_FALSE) {
-        fprintf(stderr, "%s:%d:%s\n", 
+        /* If it's a parse error then there will be a line number for the failure
+         * an I/O error (such as non-existent file) will have the error line as 0
+         */
+        if (config_error_line(&config) != 0) {
+            fprintf(stderr, "%s:%d:%s\n", 
                     filename,
                     config_error_line(&config),
                     config_error_text(&config));
-        exit(1);
+            exit(1);
+        }
+        fprintf(stderr, "%s:%s\n", 
+                filename,
+                config_error_text(&config));
+        return 1;
+    }
+
+    if(config_lookup_bool(&config, "verbose", &verbose) == CONFIG_FALSE) {
+	config_lookup_int(&config, "verbose", &verbose);
     }
 
-    config_lookup_bool(&config, "verbose", &verbose);
     config_lookup_bool(&config, "inetd", &inetd);
     config_lookup_bool(&config, "foreground", &foreground);
     config_lookup_bool(&config, "numeric", &numeric);
@@ -302,6 +401,9 @@ static int config_parse(char *filename, struct addrinfo **listen, struct proto *
 
     config_lookup_string(&config, "user", &user_name);
     config_lookup_string(&config, "pidfile", &pid_file);
+    config_lookup_string(&config, "chroot", &chroot_path);
+
+    config_lookup_string(&config, "syslog_facility", &facility);
 
     config_listen(&config, listen);
     config_protocols(&config, prots);
@@ -359,10 +461,22 @@ static void cmdline_config(int argc, char* argv[], struct proto** prots)
     optind = 1;
     opterr = 0; /* we're missing protocol options at this stage so don't output errors */
     while ((c = getopt_long_only(argc, argv, optstr, all_options, NULL)) != -1) {
+        if (c == 'v') {
+            verbose++;
+        }
         if (c == 'F') {
             config_filename = optarg;
-            /* find the end of the listen list */
-            res = config_parse(config_filename, &addr_listen, prots);
+            if (config_filename) {
+                res = config_parse(config_filename, &addr_listen, prots);
+            } else {
+                /* No configuration file specified -- try default file locations */
+                res = config_parse("/etc/sslh/sslh.cfg", &addr_listen, prots);
+                if (!res && verbose) fprintf(stderr, "Using /etc/sslh/sslh.cfg\n");
+                if (res) {
+                    res = config_parse("/etc/sslh.cfg", &addr_listen, prots);
+                    if (!res && verbose) fprintf(stderr, "Using /etc/sslh.cfg\n");
+                }
+            }
             if (res)
                 exit(4);
             break;
@@ -450,6 +564,10 @@ next_arg:
             pid_file = optarg;
             break;
 
+        case 'C':
+            chroot_path = optarg;
+            break;
+
         case 'v':
             verbose++;
             break;
@@ -467,10 +585,13 @@ next_arg:
 
     set_protocol_list(prots);
 
+/* If compiling with systemd socket support no need to require listen address */
+#ifndef SYSTEMD
     if (!addr_listen && !inetd) {
         fprintf(stderr, "No listening address specified; use at least one -p option\n");
         exit(1);
     }
+#endif
 
     /* Did command-line override foreground setting? */
     if (background)
@@ -491,6 +612,7 @@ int main(int argc, char *argv[])
    /* Init defaults */
    pid_file = NULL;
    user_name = NULL;
+   chroot_path = NULL;
 
    cmdline_config(argc, argv, &protocols);
    parse_cmdline(argc, argv, protocols);
@@ -507,6 +629,13 @@ int main(int argc, char *argv[])
 
    num_addr_listen = start_listen_sockets(&listen_sockets, addr_listen);
 
+#ifdef SYSTEMD
+   if (num_addr_listen < 1) {
+     fprintf(stderr, "No listening sockets found, restart sockets or specify addresses in config\n");
+     exit(1);
+    }
+#endif
+
    if (!foreground) {
        if (fork() > 0) exit(0); /* Detach */
 
@@ -522,13 +651,12 @@ int main(int argc, char *argv[])
    if (pid_file)
        write_pid_file(pid_file);
 
-   if (user_name)
-       drop_privileges(user_name);
-
-
-   /* Open syslog connection */
+   /* Open syslog connection before we drop privs/chroot */
    setup_syslog(argv[0]);
 
+   if (user_name || chroot_path)
+       drop_privileges(user_name, chroot_path);
+
    if (verbose)
        printcaps();
 

sslh-select.c

@@ -27,6 +27,8 @@
 
 const char* server_type = "sslh-select";
 
+#define MAX(a, b) (((a) > (b)) ? (a) : (b))
+
 /* cnx_num_alloc is the number of connection to allocate at once (at start-up,
  * and then every time we get too many simultaneous connections: e.g. start
  * with 100 slots, then if we get more than 100 connections allocate another
@@ -61,9 +63,9 @@ int tidy_connection(struct connection *cnx, fd_set *fds, fd_set *fds2)
             if (verbose)
                 fprintf(stderr, "closing fd %d\n", cnx->q[i].fd);
 
-            close(cnx->q[i].fd);
             FD_CLR(cnx->q[i].fd, fds);
             FD_CLR(cnx->q[i].fd, fds2);
+            close(cnx->q[i].fd);
             if (cnx->q[i].deferred_data)
                 free(cnx->q[i].deferred_data);
         }
@@ -93,11 +95,16 @@ int accept_new_connection(int listen_socket, struct connection *cnx[], int* cnx_
     in_socket = accept(listen_socket, 0, 0);
     CHECK_RES_RETURN(in_socket, "accept");
 
-    if (!fd_is_in_range(in_socket))
+    if (!fd_is_in_range(in_socket)) {
+        close(in_socket);
         return -1;
+    }
 
     res = set_nonblock(in_socket);
-    if (res == -1) return -1;
+    if (res == -1) {
+        close(in_socket);
+        return -1;
+    }
 
     /* Find an empty slot */
     for (free = 0; (free < *cnx_size) && ((*cnx)[free].q[0].fd != -1); free++) {
@@ -109,6 +116,7 @@ int accept_new_connection(int listen_socket, struct connection *cnx[], int* cnx_
         new = realloc(*cnx, (*cnx_size + cnx_num_alloc) * sizeof((*cnx)[0]));
         if (!new) {
             log_message(LOG_ERR, "unable to realloc -- dropping connection\n");
+            close(in_socket);
             return -1;
         }
         *cnx = new;
@@ -140,9 +148,9 @@ int connect_queue(struct connection *cnx, fd_set *fds_r, fd_set *fds_w)
         flush_deferred(q);
         if (q->deferred_data) {
             FD_SET(q->fd, fds_w);
-        } else {
-            FD_SET(q->fd, fds_r);
+            FD_CLR(cnx->q[0].fd, fds_r);
         }
+        FD_SET(q->fd, fds_r);
         return q->fd;
     } else {
         tidy_connection(cnx, fds_r, fds_w);
@@ -180,6 +188,93 @@ void shovel(struct connection *cnx, int active_fd,
     }
 }
 
+/* shovels data from one fd to the other and vice-versa
+   returns after one socket closed
+ */
+void shovel_single(struct connection *cnx)
+{
+   fd_set fds_r, fds_w;
+   int res, i;
+   int max_fd = MAX(cnx->q[0].fd, cnx->q[1].fd) + 1;
+
+   FD_ZERO(&fds_r);
+   FD_ZERO(&fds_w);
+   while (1) {
+      for (i = 0; i < 2; i++) {
+         if (cnx->q[i].deferred_data_size) {
+            FD_SET(cnx->q[i].fd, &fds_w);
+            FD_CLR(cnx->q[1-i].fd, &fds_r);
+         } else {
+            FD_CLR(cnx->q[i].fd, &fds_w);
+            FD_SET(cnx->q[1-i].fd, &fds_r);
+         }
+      }
+
+      res = select(
+                   max_fd,
+                   &fds_r,
+                   &fds_w,
+                   NULL,
+                   NULL
+                  );
+      CHECK_RES_DIE(res, "select");
+
+      for (i = 0; i < 2; i++) {
+          if (FD_ISSET(cnx->q[i].fd, &fds_w)) {
+              res = flush_deferred(&cnx->q[i]);
+              if ((res == -1) && ((errno == EPIPE) || (errno == ECONNRESET))) {
+                  if (verbose)
+                      fprintf(stderr, "%s socket closed\n", i ? "server" : "client");
+                  return;
+              }
+          }
+          if (FD_ISSET(cnx->q[i].fd, &fds_r)) {
+              res = fd2fd(&cnx->q[1-i], &cnx->q[i]);
+              if (!res) {
+                  if (verbose)
+                      fprintf(stderr, "socket closed\n");
+                  return;
+              }
+          }
+      }
+   }
+}
+
+/* Child process that makes internal connection and proxies
+ */
+void connect_proxy(struct connection *cnx)
+{
+    int in_socket;
+    int out_socket;
+
+    /* Minimize the file descriptor value to help select() */
+    in_socket = dup(cnx->q[0].fd);
+    if (in_socket == -1) {
+        in_socket = cnx->q[0].fd;
+    } else {
+        close(cnx->q[0].fd);
+        cnx->q[0].fd = in_socket;
+    }
+
+    /* Connect the target socket */
+    out_socket = connect_addr(cnx, in_socket);
+    CHECK_RES_DIE(out_socket, "connect");
+
+    cnx->q[1].fd = out_socket;
+
+    log_connection(cnx);
+
+    shovel_single(cnx);
+
+    close(in_socket);
+    close(out_socket);
+
+    if (verbose)
+        fprintf(stderr, "connection closed down\n");
+
+    exit(0);
+}
+
 /* returns true if specified fd is initialised and present in fd_set */
 int is_fd_active(int fd, fd_set* set)
 {
@@ -248,15 +343,12 @@ void main_loop(int listen_sockets[], int num_addr_listen)
         for (i = 0; i < num_addr_listen; i++) {
             if (FD_ISSET(listen_sockets[i], &readfds)) {
                 in_socket = accept_new_connection(listen_sockets[i], &cnx, &num_cnx);
-                if (in_socket != -1)
-                    num_probing++;
-
                 if (in_socket > 0) {
+                    num_probing++;
                     FD_SET(in_socket, &fds_r);
                     if (in_socket >= max_fd)
                         max_fd = in_socket + 1;;
                 }
-                FD_CLR(listen_sockets[i], &readfds);
             }
         }
 
@@ -305,6 +397,10 @@ void main_loop(int listen_sockets[], int num_addr_listen)
                          * data so probe the protocol */
                         if ((cnx[i].probe_timeout < time(NULL))) {
                             cnx[i].proto = timeout_protocol();
+                            if (verbose) 
+                                log_message(LOG_INFO, 
+                                            "timed out, connect to %s\n", 
+                                            cnx[i].proto->description);
                         } else {
                             res = probe_client_protocol(&cnx[i]);
                             if (res == PROBE_AGAIN)
@@ -314,14 +410,36 @@ void main_loop(int listen_sockets[], int num_addr_listen)
                         num_probing--;
                         cnx[i].state = ST_SHOVELING;
 
-                        /* libwrap check if required for this protocol */
-                        if (cnx[i].proto->service &&
-                            check_access_rights(in_socket, cnx[i].proto->service)) {
-                            tidy_connection(&cnx[i], &fds_r, &fds_w);
-                            res = -1;
-                        } else {
-                            res = connect_queue(&cnx[i], &fds_r, &fds_w);
-                        }
+			/* libwrap check if required for this protocol */
+			if (cnx[i].proto->service &&
+			    check_access_rights(in_socket, cnx[i].proto->service)) {
+			    tidy_connection(&cnx[i], &fds_r, &fds_w);
+			    res = -1;
+			} else if (cnx[i].proto->fork) {
+			    struct connection *pcnx_i = &cnx[i];
+			    struct connection cnx_i = *pcnx_i;
+			    switch (fork()) {
+			    case 0:  /* child */
+				for (i = 0; i < num_addr_listen; i++)
+				    close(listen_sockets[i]);
+				for (i = 0; i < num_cnx; i++)
+				    if (&cnx[i] != pcnx_i)
+					for (j = 0; j < 2; j++)
+					    if (cnx[i].q[j].fd != -1)
+						close(cnx[i].q[j].fd);
+				free(cnx);
+				connect_proxy(&cnx_i);
+				exit(0);
+			    case -1: log_message(LOG_ERR, "fork failed: err %d: %s\n", errno, strerror(errno));
+				     break;
+			    default: /* parent */
+				     break;
+			    }
+			    tidy_connection(&cnx[i], &fds_r, &fds_w);
+			    res = -1;
+			} else {
+			    res = connect_queue(&cnx[i], &fds_r, &fds_w);
+			}
 
                         if (res >= max_fd)
                             max_fd = res + 1;;

sslh.pod

@@ -6,7 +6,7 @@
 
 =head1 SYNOPSIS
 
-sslh [B<-F> I<config file>] [ B<-t> I<num> ] [B<-p> I<listening address> [B<-p> I<listening address> ...] [B<--ssl> I<target address for SSL>] [B<--ssh> I<target address for SSH>] [B<--openvpn> I<target address for OpenVPN>] [B<--http> I<target address for HTTP>] [B<--anyprot> I<default target address>] [B<--on-timeout> I<protocol name>] [B<-u> I<username>] [B<-P> I<pidfile>] [-v] [-i] [-V] [-f] [-n]
+sslh [B<-F>I<config file>] [B<-t> I<num>] [B<--transparent>] [B<-p> I<listening address> [B<-p> I<listening address> ...] [B<--ssl> I<target address for SSL>] [B<--tls> I<target address for TLS>] [B<--ssh> I<target address for SSH>] [B<--openvpn> I<target address for OpenVPN>] [B<--http> I<target address for HTTP>] [B<--xmpp> I<target address for XMPP>] [B<--tinc> I<target address for TINC>] [B<--anyprot> I<default target address>] [B<--on-timeout> I<protocol name>] [B<-u> I<username>] [B<-C> I<chroot>] [B<-P> I<pidfile>] [-v] [-i] [-V] [-f] [-n]
 
 =head1 DESCRIPTION
 
@@ -51,18 +51,14 @@ and the list of protocols).
 
 The configuration file makes it possible to specify
 protocols using regular expressions: a list of regular
-expressions is given as the I<probe> parameter, and if the
+expressions is given as the I<regex_patterns> parameter, and if the
 first packet received from the client matches any of these
 expressions, B<sslh> connects to that protocol.
 
-Alternatively, the I<probe> parameter can be set to
-"builtin", to use the compiled probes which are much faster
-than regular expressions.
-
 =head2 Probing protocols
 
 When receiving an incoming connection, B<sslh> will read the
-first bytes sent be the connecting client. It will then
+first bytes sent by the connecting client. It will then
 probe for the protocol in the order specified on the command
 line (or the configuration file). Therefore B<--anyprot>
 should alway be used last, as it always succeeds and further
@@ -72,10 +68,25 @@ If no data is sent by the client, B<sslh> will eventually
 time out and connect to the protocol specified with
 B<--on-timeout>, or I<ssh> if none is specified.
 
+=head2 Logging
+
+As a security/authorization program, B<sslh> logs to the
+LOG_AUTH facility, with priority LOG_INFO for normal
+connections and LOG_ERR for failures.
+
 =head1 OPTIONS
 
 =over 4
 
+=item B<-F>I<filename>, B<--config> I<filename>
+
+Uses I<filename> as configuration file. If other
+command-line options are specified, they will override the
+configuration file's settings.
+
+When using the shorthand version, make sure there should be
+no space between B<-F> and the I<filename>.
+
 =item B<-t> I<num>, B<--timeout> I<num>
 
 Timeout before forwarding the connection to the timeout
@@ -86,6 +97,13 @@ protocol (which should usually be SSH). Default is 2s.
 Name of the protocol to connect to after the timeout period
 is over. Default is 'ssh'.
 
+=item B<--transparent>
+
+Makes B<sslh> behave as a transparent proxy, i.e. the
+receiving service sees the original client's IP address.
+This works on Linux only and involves B<iptables> settings.
+Refer to the README for more information.
+
 =item B<-p> I<listening address>, B<--listen> I<listening address>
 
 Interface and port on which to listen, e.g. I<foobar:443>,
@@ -108,7 +126,7 @@ inside your network to just connect directly to B<httpd>.
 
 Also, B<sslh> probes for SSLv3 (or TLSv1) handshake and will
 reject connections from clients requesting SSLv2. This is
-compliant to RFC6176 which prohibits the usage of SSLv2. If
+compliant with RFC6176 which prohibits the usage of SSLv2. If
 you wish to accept SSLv2, use B<--default> instead.
 
 =item B<--ssh> I<target address>
@@ -166,6 +184,10 @@ Prints B<sslh> version.
 
 Requires to run under the specified username. 
 
+=item B<-C> I<chroot>, B<--chroot> I<chroot>
+
+Requires to run under the specified chroot.
+
 =item B<-P> I<pidfile>, B<--pidfile> I<pidfile>
 
 Specifies a file in which to write the PID of the main
@@ -211,10 +233,10 @@ detailed explanation of the variables used by B<sslh>.
 
 =head1 SEE ALSO
 
-Last version available from
+The latest version is available from
 L<http://www.rutschle.net/tech/sslh>, and can be tracked
 from L<http://freecode.com/projects/sslh>.
 
 =head1 AUTHOR
 
-Written by Yves Rutschle
+Written by Yves Rutschle.

systemd-sslh-generator.c

@@ -0,0 +1,148 @@
+#include <libconfig.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+
+static char* resolve_listen(const char *hostname, const char *port) {
+    /* Need room in the strcat for \0 and :
+     * the format in the socket unit file is hostname:port */
+    char *conn = (char*)malloc(strlen(hostname)+strlen(port)+2);
+    strcpy(conn, hostname);
+    strcat(conn, ":");
+    strcat(conn, port);
+
+    return conn;
+
+}
+
+
+static int get_listen_from_conf(const char *filename, char **listen[]) {
+    config_t config;
+    config_setting_t *setting, *addr;
+    const char *hostname, *port;
+    int len = 0;
+
+    /* look up the listen stanzas in the config file so these
+     * can be used in the socket file generated */
+    config_init(&config);
+    if (config_read_file(&config, filename) == CONFIG_FALSE) {
+        /* we don't care if file is missing, skip it */
+        if (config_error_line(&config) != 0) {
+            fprintf(stderr, "%s:%d:%s\n",
+                    filename,
+                    config_error_line(&config),
+                    config_error_text(&config));
+            return -1;
+        }
+    } else {
+        setting = config_lookup(&config, "listen");
+        if (setting) {
+	    int i;
+            len = config_setting_length(setting);
+            *listen = malloc(len * sizeof(**listen));
+            for (i = 0; i < len; i++) {
+                addr = config_setting_get_elem(setting, i);
+                if (! (config_setting_lookup_string(addr, "host", &hostname) &&
+                       config_setting_lookup_string(addr, "port", &port))) {
+                    fprintf(stderr,
+                            "line %d:Incomplete specification (hostname and port required)\n",
+                            config_setting_source_line(addr));
+                    return -1;
+                } else {
+                    (*listen)[i] = malloc(strlen(resolve_listen(hostname, port)));
+                    strcpy((*listen)[i], resolve_listen(hostname, port));
+                }
+            }
+        }
+    }
+
+    return len;
+
+}
+
+static int write_socket_unit(FILE *socket, char *listen[], int num_addr, const char *source) {
+    int i;
+
+    fprintf(socket,
+            "# Automatically generated by systemd-sslh-generator\n\n"
+            "[Unit]\n"
+            "Before=sslh.service\n"
+            "SourcePath=%s\n"
+            "Documentation=man:sslh(8) man:systemd-sslh-generator(8)\n\n"
+            "[Socket]\n"
+            "FreeBind=true\n",
+            source);
+
+    for (i = 0; i < num_addr; i++) {
+        fprintf(socket, "ListenStream=%s\n", listen[i]);
+    }
+
+    return 0;
+}
+
+static int gen_sslh_config(char *runtime_unit_dir) {
+    char *sslh_conf;
+    int num_addr;
+    FILE *config;
+    char **listen;
+    FILE *runtime_conf_fd = stdout;
+    const char *unit_file;
+
+    /* There are two default locations so check both with first given preference */
+    sslh_conf = "/etc/sslh.cfg";
+
+    config = fopen(sslh_conf, "r");
+    if (config  == NULL) {
+        sslh_conf="/etc/sslh/sslh.cfg";
+        config = fopen(sslh_conf, "r");
+        if (config == NULL) {
+            return -1;
+        }
+    }
+
+    fclose(config);
+
+    num_addr = get_listen_from_conf(sslh_conf, &listen);
+    if (num_addr < 0)
+        return -1;
+
+    /* If this is run by systemd directly write to the location told to
+     * otherwise write to standard out so that it's trivial to check what
+     * will be written */
+    if (runtime_unit_dir && *runtime_unit_dir) {
+        unit_file = "/sslh.socket";
+        size_t uf_len = strlen(unit_file);
+        size_t runtime_len = strlen(runtime_unit_dir) + uf_len + 1;
+        char *runtime_conf = malloc(runtime_len);
+        strcpy(runtime_conf, runtime_unit_dir);
+        strcat(runtime_conf, unit_file);
+        runtime_conf_fd = fopen(runtime_conf, "w");
+    }
+
+
+    return write_socket_unit(runtime_conf_fd, listen, num_addr, sslh_conf);
+}
+
+
+int main(int argc, char *argv[]){
+    int r = 0;
+    int k;
+    char *runtime_unit_dest = "";
+
+    if (argc > 1 && (argc != 4) ) {
+        printf("This program takes three or no arguments.\n");
+        return -1;
+    }
+
+    if (argc  > 1)
+        runtime_unit_dest = argv[1];
+
+    k = gen_sslh_config(runtime_unit_dest);
+    if (k < 0)
+        r = k;
+
+    return r < 0 ? -1 : 0;
+}
+
+

t

@@ -295,21 +295,6 @@ if ($RB_OPEN_PID_FILE) {
     is($code, 3, "Exit status if can't open PID file");
 }
 
-# Robustness: Can't bind address
-if ($RB_BIND_ADDRESS) {
-    print "***Test: Can't bind address\n";
-    my $sslh_pid;
-    if (!($sslh_pid = fork)) {
-        my $user = (getpwuid $<)[0]; # Run under current username
-        exec "./sslh-select -v -f -u $user --listen 74.125.39.106:9000 --ssh $ssh_address --ssl $ssl_address -P $pidfile";
-    }
-    warn "spawned $sslh_pid\n";
-    waitpid $sslh_pid, 0;
-    my $code = $? >> 8;
-    warn "exited with $code\n";
-    is($code, 1, "Exit status if can't bind address");
-}
-
 # Robustness: Can't resolve address
 if ($RB_RESOLVE_ADDRESS) {
     print "***Test: Can't resolve address\n";

tls.c

@@ -0,0 +1,336 @@
+/*
+ * Copyright (c) 2011 and 2012, Dustin Lundquist <dustin@null-ptr.net>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+/*
+ * This is a minimal TLS implementation intended only to parse the server name
+ * extension.  This was created based primarily on Wireshark dissection of a
+ * TLS handshake and RFC4366.
+ */
+#include <stdio.h>
+#include <stdlib.h> /* malloc() */
+#include <fnmatch.h> /* fnmatch() */
+#include "tls.h"
+
+#define TLS_HEADER_LEN 5
+#define TLS_HANDSHAKE_CONTENT_TYPE 0x16
+#define TLS_HANDSHAKE_TYPE_CLIENT_HELLO 0x01
+
+#ifndef MIN
+#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
+#endif
+
+
+struct TLSProtocol {
+    int use_alpn;
+    char** sni_hostname_list;
+    char** alpn_protocol_list;
+};
+
+static int parse_extensions(const struct TLSProtocol *, const char *, size_t);
+static int parse_server_name_extension(const struct TLSProtocol *, const char *, size_t);
+static int parse_alpn_extension(const struct TLSProtocol *, const char *, size_t);
+static int has_match(char**, const char*, size_t);
+
+/* Parse a TLS packet for the Server Name Indication and ALPN extension in the client
+ * hello handshake, returning a status code
+ *
+ * Returns:
+ *  >=0  - length of the hostname and updates *hostname
+ *         caller is responsible for freeing *hostname
+ *  -1   - Incomplete request
+ *  -2   - No Host header included in this request
+ *  -3   - Invalid hostname pointer
+ *  < -4 - Invalid TLS client hello
+ */
+int
+parse_tls_header(const struct TLSProtocol *tls_data, const char *data, size_t data_len) {
+    char tls_content_type;
+    char tls_version_major;
+    char tls_version_minor;
+    size_t pos = TLS_HEADER_LEN;
+    size_t len;
+
+    /* Check that our TCP payload is at least large enough for a TLS header */
+    if (data_len < TLS_HEADER_LEN)
+        return -1;
+
+    tls_content_type = data[0];
+    if (tls_content_type != TLS_HANDSHAKE_CONTENT_TYPE) {
+        if (verbose) fprintf(stderr, "Request did not begin with TLS handshake.\n");
+        return -5;
+    }
+
+    tls_version_major = data[1];
+    tls_version_minor = data[2];
+    if (tls_version_major < 3) {
+        if (verbose) fprintf(stderr, "Received SSL %d.%d handshake which cannot be parsed.\n",
+              tls_version_major, tls_version_minor);
+
+        return -2;
+    }
+
+    /* TLS record length */
+    len = ((unsigned char)data[3] << 8) +
+          (unsigned char)data[4] + TLS_HEADER_LEN;
+    data_len = MIN(data_len, len);
+
+    /* Check we received entire TLS record length */
+    if (data_len < len)
+        return -1;
+
+    /*
+     * Handshake
+     */
+    if (pos + 1 > data_len) {
+        return -5;
+    }
+    if (data[pos] != TLS_HANDSHAKE_TYPE_CLIENT_HELLO) {
+        if (verbose) fprintf(stderr, "Not a client hello\n");
+
+        return -5;
+    }
+
+    /* Skip past fixed length records:
+       1	Handshake Type
+       3	Length
+       2	Version (again)
+       32	Random
+       to	Session ID Length
+     */
+    pos += 38;
+
+    /* Session ID */
+    if (pos + 1 > data_len)
+        return -5;
+    len = (unsigned char)data[pos];
+    pos += 1 + len;
+
+    /* Cipher Suites */
+    if (pos + 2 > data_len)
+        return -5;
+    len = ((unsigned char)data[pos] << 8) + (unsigned char)data[pos + 1];
+    pos += 2 + len;
+
+    /* Compression Methods */
+    if (pos + 1 > data_len)
+        return -5;
+    len = (unsigned char)data[pos];
+    pos += 1 + len;
+
+    if (pos == data_len && tls_version_major == 3 && tls_version_minor == 0) {
+        if (verbose) fprintf(stderr, "Received SSL 3.0 handshake without extensions\n");
+        return -2;
+    }
+
+    /* Extensions */
+    if (pos + 2 > data_len)
+        return -5;
+    len = ((unsigned char)data[pos] << 8) + (unsigned char)data[pos + 1];
+    pos += 2;
+
+    if (pos + len > data_len)
+        return -5;
+    return parse_extensions(tls_data, data + pos, len);
+}
+
+static int
+parse_extensions(const struct TLSProtocol *tls_data, const char *data, size_t data_len) {
+    size_t pos = 0;
+    size_t len;
+    int last_matched = 0;
+
+    if (tls_data == NULL)
+        return -3;
+
+    /* Parse each 4 bytes for the extension header */
+    while (pos + 4 <= data_len) {
+        /* Extension Length */
+        len = ((unsigned char) data[pos + 2] << 8) +
+              (unsigned char) data[pos + 3];
+
+        if (pos + 4 + len > data_len)
+            return -5;
+
+        size_t extension_type = ((unsigned char) data[pos] << 8) +
+                                (unsigned char) data[pos + 1];
+
+
+        /* Check if it's a server name extension */
+        /* There can be only one extension of each type, so we break
+           our state and move pos to beginning of the extension here */
+        if (tls_data->use_alpn == 2) {
+            /* we want BOTH alpn and sni to match */
+            if (extension_type == 0x00) { /* Server Name */
+                if (parse_server_name_extension(tls_data, data + pos + 4, len)) {
+                    /* SNI matched */
+                    if(last_matched) {
+                        /* this is only true if ALPN matched, so return true */
+                        return last_matched;
+                    } else {
+                        /* otherwise store that SNI matched */
+                        last_matched = 1;
+                    }
+                } else {
+                    /* both can't match */
+                    return -2;
+                }
+            } else if (extension_type == 0x10) { /* ALPN */
+                if (parse_alpn_extension(tls_data, data + pos + 4, len)) {
+                    /* ALPN matched */
+                    if(last_matched) {
+                        /* this is only true if SNI matched, so return true */
+                        return last_matched;
+                    } else {
+                        /* otherwise store that ALPN matched */
+                        last_matched = 1;
+                    }
+                } else {
+                    /* both can't match */
+                    return -2;
+                }
+            }
+
+        } else if (extension_type == 0x00 && tls_data->use_alpn == 0) { /* Server Name */
+            return parse_server_name_extension(tls_data, data + pos + 4, len);
+        } else if (extension_type == 0x10 && tls_data->use_alpn == 1) { /* ALPN */
+            if (parse_alpn_extension(tls_data, data + pos + 4, len) > 0) {
+                return 1;
+            }
+            return parse_alpn_extension(tls_data, data + pos + 4, len);
+        }
+
+        pos += 4 + len; /* Advance to the next extension header */
+    }
+
+    /* Check we ended where we expected to */
+    if (pos != data_len)
+        return -5;
+
+    return -2;
+}
+
+static int
+parse_server_name_extension(const struct TLSProtocol *tls_data, const char *data, size_t data_len) {
+    size_t pos = 2; /* skip server name list length */
+    size_t len;
+
+    while (pos + 3 < data_len) {
+        len = ((unsigned char)data[pos + 1] << 8) +
+              (unsigned char)data[pos + 2];
+
+        if (pos + 3 + len > data_len)
+            return -5;
+
+        switch (data[pos]) { /* name type */
+            case 0x00: /* host_name */
+                if(has_match(tls_data->sni_hostname_list, data + pos + 3, len)) {
+                    return len;
+                } else {
+                    return -2;
+                }
+            default:
+                if (verbose) fprintf(stderr, "Unknown server name extension name type: %d\n",
+                      data[pos]);
+        }
+        pos += 3 + len;
+    }
+    /* Check we ended where we expected to */
+    if (pos != data_len)
+        return -5;
+
+    return -2;
+}
+
+static int
+parse_alpn_extension(const struct TLSProtocol *tls_data, const char *data, size_t data_len) {
+    size_t pos = 2;
+    size_t len;
+
+    while (pos + 1 < data_len) {
+        len = (unsigned char)data[pos];
+
+        if (pos + 1 + len > data_len)
+            return -5;
+
+        if (len > 0 && has_match(tls_data->alpn_protocol_list, data + pos + 1, len)) {
+            return len;
+        } else if (len > 0) {
+            if (verbose) fprintf(stderr, "Unknown ALPN name: %.*s\n", (int)len, data + pos + 1);
+        }
+        pos += 1 + len;
+    }
+    /* Check we ended where we expected to */
+    if (pos != data_len)
+        return -5;
+
+    return -2;
+}
+
+static int
+has_match(char** list, const char* name, size_t name_len) {
+    char **item;
+    char *name_nullterminated = malloc(name_len+1);
+    memcpy(name_nullterminated, name, name_len);
+    name_nullterminated[name_len]='\0';
+
+    for (item = list; *item; item++) {
+        if (verbose) fprintf(stderr, "matching [%.*s] with [%s]\n", (int)name_len, name, *item);
+        if(!fnmatch(*item, name_nullterminated, 0)) {
+            free(name_nullterminated);
+            return 1;
+        }
+    }
+    free(name_nullterminated);
+    return 0;
+}
+
+struct TLSProtocol *
+new_tls_data() {
+    struct TLSProtocol *tls_data = malloc(sizeof(struct TLSProtocol));
+    if (tls_data != NULL) {
+        tls_data->use_alpn = -1;
+    }
+
+    return tls_data;
+}
+
+struct TLSProtocol *
+tls_data_set_list(struct TLSProtocol *tls_data, int alpn, char** list) {
+    if (alpn) {
+        tls_data->alpn_protocol_list = list;
+        if(tls_data->use_alpn == 0)
+            tls_data->use_alpn = 2;
+        else
+            tls_data->use_alpn = 1;
+    } else {
+        tls_data->sni_hostname_list = list;
+        if(tls_data->use_alpn == 1)
+            tls_data->use_alpn = 2;
+        else
+            tls_data->use_alpn = 0;
+    }
+
+    return tls_data;
+}

tls.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2011 and 2012, Dustin Lundquist <dustin@null-ptr.net>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef TLS_H
+#define TLS_H
+
+#include "common.h"
+
+struct TLSProtocol;
+
+int parse_tls_header(const struct TLSProtocol *tls_data, const char *data, size_t data_len);
+
+struct TLSProtocol *new_tls_data();
+struct TLSProtocol *tls_data_set_list(struct TLSProtocol *, int, char**);
+
+#endif