Changelog prepared for v1.16

sslh-fork: close all listening sockets in shoveler

.gitignore

@@ -0,0 +1,10 @@
+*.swp
+*.swo
+*.o
+cscope.*
+echosrv
+sslh-fork
+sslh-select
+sslh.8.gz
+tags
+version.h

ChangeLog

@@ -1,3 +1,64 @@
+v1.16:	11FEB2014
+	Probes made more resilient, to incoming data
+	containing NULLs. Also made them behave properly
+	when receiving too short packets to probe on the
+	first incoming packet.
+	(Ondrej Kuzník)
+
+	Libcap support: Keep only CAP_NET_ADMIN if started
+	as root with transparent proxying and dropping
+	priviledges (enable USELIBCAP in Makefile). This
+	avoids having to mess with filesystem capabilities.
+	(Sebastian Schmidt/yath)
+
+	Fixed bugs related to getpeername that would cause
+	sslh to quit erroneously (getpeername can return
+	actual errors if connections are dropped before
+	getting to getpeername).
+
+	Set IP_FREEDBIND if available to bind to addresses
+	that don't yet exist.
+
+v1.15:	27JUL2013
+	Added --transparent option for transparent proxying.
+	See README for iptables magic and capability
+	management.
+
+	Fixed bug in sslh-select: if number of opened file
+	descriptor became bigger than FD_SETSIZE, bad things
+	would happen.
+
+	Fixed bug in sslh-select: if socket dropped while
+	deferred_data was present, sslh-select would crash.
+
+	Increased FD_SETSIZE for Cygwin, as the default 64
+	is too low for even moderate load.
+
+v1.14: 21DEC2012
+	Corrected OpenVPN probe to support pre-shared secret
+	mode (OpenVPN port-sharing code is... wrong). Thanks
+	to Kai Ellinger for help in investigating and
+	testing.
+
+	Added an actual TLS/SSL probe.
+
+	Added configurable --on-timeout protocol
+	specification.
+
+	Added a --anyprot protocol probe (equivalent to what
+	--ssl was).
+
+	Makefile respects the user's compiler and CFLAG
+	choices (falling back to the current values if
+	undefined), as well as LDFLAGS. 
+	(Michael Palimaka)
+
+	Added "After" and "KillMode" to systemd.sslh.service
+	(Thomas Weißschuh).
+
+	Added LSB tags to etc.init.d.sslh
+	(Thomas Varis).
+
 v1.13: 18MAY2012
 	Write PID file before dropping privileges.
 

Makefile

@@ -1,8 +1,9 @@
 # Configuration
 
-VERSION="v1.13b"
+VERSION=$(shell ./genver.sh -r)
 USELIBCONFIG=1	# Use libconfig? (necessary to use configuration files)
 USELIBWRAP=	# Use libwrap?
+USELIBCAP=	# Use libcap?
 COV_TEST= 	# Perform test coverage?
 PREFIX=/usr/local
 
@@ -15,48 +16,60 @@ ifneq ($(strip $(COV_TEST)),)
     CFLAGS_COV=-fprofile-arcs -ftest-coverage
 endif
 
-CC = gcc
-CFLAGS=-Wall -g $(CFLAGS_COV)
+CC ?= gcc
+CFLAGS ?=-Wall -g $(CFLAGS_COV)
 
 LIBS=
 OBJS=common.o sslh-main.o probe.o
 
 ifneq ($(strip $(USELIBWRAP)),)
 	LIBS:=$(LIBS) -lwrap
-	CFLAGS:=$(CFLAGS) -DLIBWRAP
+	CPPFLAGS+=-DLIBWRAP
 endif
 
 ifneq ($(strip $(USELIBCONFIG)),)
 	LIBS:=$(LIBS) -lconfig
-	CFLAGS:=$(CFLAGS) -DLIBCONFIG
+	CPPFLAGS+=-DLIBCONFIG
+endif
+
+ifneq ($(strip $(USELIBCAP)),)
+	LIBS:=$(LIBS) -lcap
+	CPPFLAGS+=-DLIBCAP
 endif
 
 all: sslh $(MAN) echosrv
 
 .c.o: *.h
-	$(CC) $(CFLAGS) -D'VERSION=$(VERSION)' -c $<
+	$(CC) $(CFLAGS) $(CPPFLAGS) -c $<
 
+version.h:
+	./genver.sh >version.h
 
-sslh: $(OBJS) sslh-fork sslh-select
+sslh: sslh-fork sslh-select
 
-sslh-fork: $(OBJS) sslh-fork.o Makefile common.h
-	$(CC) $(CFLAGS) -D'VERSION=$(VERSION)' -o sslh-fork sslh-fork.o $(OBJS) $(LIBS)
+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
 
-sslh-select: $(OBJS) sslh-select.o Makefile common.h 
-	$(CC) $(CFLAGS) -D'VERSION=$(VERSION)' -o sslh-select sslh-select.o $(OBJS) $(LIBS)
+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) -o echosrv echosrv.o common.o $(LIBS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -o echosrv echosrv.o probe.o common.o $(LIBS)
 
 $(MAN): sslh.pod Makefile
 	pod2man --section=8 --release=$(VERSION) --center=" " sslh.pod | gzip -9 - > $(MAN)
 
+# Create release: export clean tree and tag current
+# configuration
+release:
+	git archive master --prefix="sslh-$(VERSION)/" | gzip > /tmp/sslh-$(VERSION).tar.gz
+
 # generic install: install binary and man page
 install: sslh $(MAN)
-	install -D sslh-fork $(PREFIX)/sbin/sslh
-	install -D -m 0644 $(MAN) $(PREFIX)/share/man/man8/$(MAN)
+	install -pD sslh-fork $(DESTDIR)$(PREFIX)/sbin/sslh
+	install -pD -m 0644 $(MAN) $(DESTDIR)$(PREFIX)/share/man/man8/$(MAN)
 
 # "extended" install for Debian: install startup script
 install-debian: install sslh $(MAN)
@@ -66,15 +79,22 @@ install-debian: install sslh $(MAN)
 	update-rc.d sslh defaults
 
 uninstall:
-	rm -f $(PREFIX)/sbin/sslh $(PREFIX)/share/man/man8/$(MAN) /etc/init.d/sslh /etc/default/sslh
+	rm -f $(DESTDIR)$(PREFIX)/sbin/sslh $(DESTDIR)$(PREFIX)/share/man/man8/$(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 $(MAN) *.o *.gcov *.gcno *.gcda *.png *.html *.css *.info 
+	rm -f sslh-fork sslh-select echosrv version.h $(MAN) *.o *.gcov *.gcno *.gcda *.png *.html *.css *.info
 
 tags:
 	ctags --globals -T *.[ch]
 
+cscope:
+	-find . -name "*.[chS]" >cscope.files
+	-cscope -b -R
+
 test:
 	./t
 

README

@@ -1,188 +0,0 @@
-===== sslh -- A ssl/ssh multiplexer. =====
-
-sslh accepts connections in HTTP, HTTPS, SSH, OpenVPN,
-tinc, XMPP, or any other protocol that can be tested using a
-regular expression, on the same port. This makes it possible
-to connect to any of these servers on port 443 (e.g. from
-inside a corporate firewall, which almost never block port
-443) while still serving HTTPS on that port. 
-
-
-==== Compile and install ====
-
-sslh uses libconfig (http://www.hyperrealm.com/libconfig/)
-and libwrap.
-
-For Debian, these are contained in packages libwrap0-dev and
-libconfig8-dev.  
-
-For OpenSUSE, these are contained in packages libconfig9 and
-libconfig-dev in repository
-http://download.opensuse.org/repositories/multimedia:/libs/openSUSE_12.1/
-
-For Fedora, this package should work:
-https://admin.fedoraproject.org/pkgdb/acls/name/libconfig
-(feedback from Fedorans appreciated).
-
-If you can't find libconfig, or just don't want a
-configuration file, set 'USELIBCONFIG=' in the Makefile.
-
-After this, the Makefile should work:
-
-make install
-
-There are a couple of configuration options at the beginning
-of the Makefile: 
-
-    USELIBWRAP compiles support for host access control (see
-    hosts_access(3)), you will need libwrap headers and
-    library to compile (libwrap0-dev in Debian).
-
-    USELIBCONFIG compiles support for the configuration
-    file. You will need libconfig headers to compile
-    (libconfig8-dev in Debian).
-
-The Makefile produces two different executables: sslh-fork
-and sslh-select. 
-
-sslh-fork forks a new process for each incoming connection.
-It is well-tested and very reliable, but incurs the overhead
-of many processes.  sslh-select uses only one thread, which
-monitors all connections at once. It is more recent and less
-tested, but only incurs a 16 byte overhead per connection.
-Also, if it stops, you'll lose all connections, which means
-you can't upgrade it remotely.
-
-If you are going to use sslh for a "small" setup (less than
-a dozen ssh connections and a low-traffic https server) then
-sslh-fork is probably more suited for you. If you are going
-to use sslh on a "medium" setup (a few thousand ssh
-connections, and another few thousand sslh connections),
-sslh-select will be better. If you have a very large site
-(tens of thousands of connections), you'll need a vapourware
-version that would use libevent or something like that.
-
-
-To install:
-
-make
-cp sslh-fork /usr/local/sbin/sslh
-cp scripts/etc.default.sslh /etc/default/sslh
-
-For Debian:
-cp scripts/etc.init.d.sslh /etc/init.d/sslh
-For CentOS:
-cp scripts/etc.rc.d.init.d.sslh /etc/rc.d/init.d/sslh
-
-and probably create links in /etc/rc<x>.d so that the server
-start automatically at boot-up, e.g. under Debian:
-update-rc.d sslh defaults
-
-
-
-==== Configuration ====
-
-You can edit settings in /etc/default/sslh:
-
-LISTEN=ifname:443
-SSH=localhost:22
-SSL=localhost:443
-
-A good scheme is to use the external name of the machine in
-$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
-coming from the internet.
-
-Note that 'external name' in this context refers to the
-actual IP address of the machine as seen from your network,
-i.e. that that is not 127.0.0.1 in the output of
-ifconfig(8).
-
-==== Libwrap support ====
-
-Sslh can optionnaly 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.
-
-==== 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
-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
-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.
-
-==== Using proxytunnel with sslh ====
-
-If you are connecting through a proxy that checks that the
-outgoing connection really is SSL and rejects SSH, you can
-encapsulate all your traffic in SSL using proxytunnel (this
-should work with corkscrew as well). On the server side you
-receive the traffic with stunnel to decapsulate SSL, then
-pipe through sslh to switch HTTP on one side and SSL on the
-other.
-
-In that case, you end up with something like this:
-
-ssh -> proxytunnel -e --------ssh/ssl------> stunnel ---ssh---> sslh --> sshd
-
-Web browser --------http/ssl------> stunnel ---http---> sslh --> http:80
-
-Configuration goes like this:
-
-On the server side, using stunnel3:
-stunnel -f -p mycert.pem  -d thelonious:443 -l /usr/local/sbin/sslh -- sslh -i  --ssl localhost:80 --ssh localhost:22
-
-stunnel options: -f for foreground/debugging, -p specifies
-the key + certificate, -d specifies which interface and port
-we're listening to for incoming connexions, -l summons sslh
-in inetd mode.
-
-sslh options: -i for inetd mode, --ssl to forward SSL
-connexions (in fact normal HTTP at that stage) to port 80,
-and SSH connexions to port 22. This works because sslh
-considers that any protocol it doesn't recognise is SSL.
-
-==== IP_TPROXY support ====
-
-There is a netfilter patch that adds an option to the Linux
-TCP/IP stack to allow a program to set the source address
-of an IP packet that it sends. This could let sslh set the
-address of packets to that of the actual client, so that
-sshd would see and log the IP address of the client, making
-sslh transparent.
-
-This is not, and won't be, implemented in sslh for the
-following reasons (in increasing order of importance):
-
-  * It's not vital: the real connecting IP address can be
-    found in logs. Little gain.
-  * It's Linux only: it means increased complexity for no
-    gain to some users.
-  * It's a patch: it means it'd only be useful to Linux
-    users who compile their own kernel.
-  * Only root can use the feature: that's a definite no-no.
-    Sslh should not, must not, will never run as root.
-
-This isn't to mean that it won't eventually get implemented,
-when/if the feature finds its way into the main kernel and
-it becomes usuable by non-root processes.
-
-
-==== Comments? Questions? ====
-
-You can subscribe to the sslh mailing list here:
-http://rutschle.net/cgi-bin/mailman/listinfo/sslh
-
-This mailing list should be used for discussion, feature
-requests, and will be the prefered channel for
-announcements.
-

README.md

@@ -0,0 +1,261 @@
+sslh -- A ssl/ssh multiplexer
+=============================
+
+`sslh` accepts connections on specified ports, and forwards
+them further based on tests performed on the first data
+packet sent by the remote client.
+
+Probes for HTTP, SSL, SSH, OpenVPN, tinc, XMPP are
+implemented, and any other protocol that can be tested using
+a regular expression, can be recognised. A typical use case
+is to allow serving several services on port 443 (e.g. to
+connect to SSH from inside a corporate firewall, which
+almost never block port 443) while still serving HTTPS on
+that port. 
+
+Hence `sslh` acts as a protocol demultiplexer, or a
+switchboard. Its name comes from its original function to
+serve SSH and HTTPS on the same port.
+
+Compile and install
+===================
+
+Dependencies
+------------
+
+`sslh` uses [libconfig](http://www.hyperrealm.com/libconfig/)
+and [libwrap](http://packages.debian.org/source/unstable/tcp-wrappers).
+
+For Debian, these are contained in packages `libwrap0-dev` and
+`libconfig8-dev`.
+
+For OpenSUSE, these are contained in packages libconfig9 and
+libconfig-dev in repository
+<http://download.opensuse.org/repositories/multimedia:/libs/openSUSE_12.1/>
+
+For Fedora, you'll need packages `libconfig` and
+`libconfig-devel`:
+
+	yum install libconfig libconfig-devel
+
+If you can't find `libconfig`, or just don't want a
+configuration file, set `USELIBCONFIG=` in the Makefile.
+
+Compilation
+-----------
+
+After this, the Makefile should work:
+
+	make install
+
+There are a couple of configuration options at the beginning
+of the Makefile: 
+
+* `USELIBWRAP` compiles support for host access control (see
+  `hosts_access(3)`), you will need `libwrap` headers and
+  library to compile (`libwrap0-dev` in Debian).
+
+* `USELIBCONFIG` compiles support for the configuration
+  file. You will need `libconfig` headers to compile
+  (`libconfig8-dev` in Debian).
+
+
+Binaries
+--------
+
+The Makefile produces two different executables: `sslh-fork`
+and `sslh-select`:
+
+* `sslh-fork` forks a new process for each incoming connection.
+It is well-tested and very reliable, but incurs the overhead
+of many processes.  
+If you are going to use `sslh` for a "small" setup (less than
+a dozen ssh connections and a low-traffic https server) then
+`sslh-fork` is probably more suited for you. 
+
+* `sslh-select` uses only one thread, which monitors all connections
+at once. It is more recent and less tested, but only incurs a 16
+byte overhead per connection. Also, if it stops, you'll lose all
+connections, which means you can't upgrade it remotely.  
+If you are going to use `sslh` on a "medium" setup (a few thousand ssh
+connections, and another few thousand ssl connections),
+`sslh-select` will be better.
+
+If you have a very large site (tens of thousands of connections),
+you'll need a vapourware version that would use libevent or
+something like that.
+
+
+Installation
+------------
+
+* In general:
+
+		make
+		cp sslh-fork /usr/local/sbin/sslh
+		cp scripts/etc.default.sslh /etc/default/sslh
+
+* For Debian:
+
+		cp scripts/etc.init.d.sslh /etc/init.d/sslh
+	
+* For CentOS:
+
+		cp scripts/etc.rc.d.init.d.sslh /etc/rc.d/init.d/sslh
+
+
+You might need to create links in /etc/rc<x>.d so that the server
+start automatically at boot-up, e.g. under Debian:
+
+	update-rc.d sslh defaults
+
+
+Configuration
+=============
+
+You can edit settings in /etc/default/sslh:
+
+	LISTEN=ifname:443
+	SSH=localhost:22
+	SSL=localhost:443
+
+A good scheme is to use the external name of the machine in
+`$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
+coming from the internet.
+
+Note that 'external name' in this context refers to the
+actual IP address of the machine as seen from your network,
+i.e. that that is not `127.0.0.1` in the output of
+`ifconfig(8)`.
+
+Libwrap support
+---------------
+
+Sslh can optionnaly 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.
+
+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
+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
+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.
+
+Using proxytunnel with sslh
+---------------------------
+
+If you are connecting through a proxy that checks that the
+outgoing connection really is SSL and rejects SSH, you can
+encapsulate all your traffic in SSL using `proxytunnel` (this
+should work with `corkscrew` as well). On the server side you
+receive the traffic with `stunnel` to decapsulate SSL, then
+pipe through `sslh` to switch HTTP on one side and SSL on the
+other.
+
+In that case, you end up with something like this:
+
+	ssh -> proxytunnel -e ----[ssh/ssl]---> stunnel ---[ssh]---> sslh --> sshd
+	Web browser -------------[http/ssl]---> stunnel ---[http]--> sslh --> httpd
+
+Configuration goes like this on the server side, using `stunnel3`:
+
+	stunnel -f -p mycert.pem  -d thelonious:443 -l /usr/local/sbin/sslh -- \
+		sslh -i  --http localhost:80 --ssh localhost:22
+
+* stunnel options:
+  * `-f` for foreground/debugging
+  * `-p` for specifying the key and certificate
+  * `-d` for specifying which interface and port
+	we're listening to for incoming connexions
+  * `-l` summons `sslh` in inetd mode.
+
+* sslh options:
+  * `-i` for inetd mode
+  * `--http` to forward HTTP connexions to port 80,
+	and SSH connexions to port 22.
+
+Capabilities support
+--------------------
+
+On Linux (only?), you can compile sslh with `USELIBCAP=1` to
+make use of POSIX capabilities; this will save the required
+capabilities needed for transparent proxying for unprivileged
+processes.
+
+Alternatively, you may use filesystem capabilities instead
+of starting sslh as root and asking it to drop privileges.
+You will need `CAP_NET_BIND_SERVICE` for listening on port 443
+and `CAP_NET_ADMIN` for transparent proxying (see
+`capabilities(7)`).
+
+You can use the `setcap(8)` utility to give these capabilities
+to the executable:
+
+	# setcap cap_net_bind_service,cap_net_admin+pe sslh-select
+
+Then you can run sslh-select as an unpriviledged user, e.g.:
+
+	$ sslh-select -p myname:443 --ssh localhost:22 --ssl localhost:443
+
+Caveat: `CAP_NET_ADMIN` does give sslh too many rights, e.g.
+configuring the interface. If you're not going to use
+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`
+(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).
+
+`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
+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
+
+This will only work if `sslh` does not use any loopback
+addresses (no `127.0.0.1` or `localhost`), you'll need to use
+explicit IP addresses (or names):
+
+	sslh --listen 192.168.0.1:443 --ssh 192.168.0.1:22 --ssl 192.168.0.1:4443
+
+This will not work:
+
+	sslh --listen 192.168.0.1:443 --ssh 127.0.0.1:22 --ssl 127.0.0.1:4443
+
+Comments? Questions?
+====================
+
+You can subscribe to the `sslh` mailing list here:
+<http://rutschle.net/cgi-bin/mailman/listinfo/sslh>
+
+This mailing list should be used for discussion, feature
+requests, and will be the prefered channel for announcements.
+

TODO

@@ -0,0 +1,25 @@
+Here's a list of features that have been suggested or
+sometimes requested. This list is not a roadmap and
+shouldn't be construed to mean that any of this will happen.
+
+- configurable behaviour depending on services (e.g.
+  select() for ssl but fork() for ssh).
+
+- have certain services available only from specified subnets
+
+- some sort of "service knocking" allowing to activate a
+  service upon some external even, similar to port knocking;
+for example, go to a specific URL to enable sslh forwarding
+to sshd for a set period of time:
+    * sslh listens on 443 and only directs to httpd
+    * user goes somewhere to https://example.org/open_ssh.cgi
+    * open_ssh.cgi tells sslh
+    * sslh starts checking if incoming connections are ssh, and
+    if they are, forward to sshd
+    * 10 minutes later, sslh stops forwarding to ssh
+
+That would make it almost impossible for an observer
+(someone who'd telnet regularly on 443) to ever notice both
+services are available on 443.
+
+

basic.cfg

@@ -0,0 +1,29 @@
+# This is a basic configuration file that should provide
+# sensible values for "standard" setup.
+
+verbose: false;
+foreground: false;
+inetd: false;
+numeric: false;
+transparent: false;
+timeout: 2;
+user: "nobody";
+pidfile: "/var/run/sslh.pid";
+
+
+# Change hostname with your external address name.
+listen:
+(
+    { host: "thelonious"; port: "443"; }
+);
+
+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"; }
+);
+

common.c

@@ -8,6 +8,7 @@
 #include <stdarg.h>
 
 #include "common.h"
+#include "probe.h"
 
 /* Added to make the code compilable under CYGWIN 
  * */
@@ -25,8 +26,9 @@ int probing_timeout = 2;
 int inetd = 0;
 int foreground = 0;
 int background = 0;
+int transparent = 0;
 int numeric = 0;
-const char *user_name, *pid_file, *rule_filename;
+const char *user_name, *pid_file;
 
 struct addrinfo *addr_listen = NULL; /* what addresses do we listen to? */
 
@@ -35,7 +37,6 @@ struct addrinfo *addr_listen = NULL; /* what addresses do we listen to? */
 int allow_severity =0, deny_severity = 0;
 #endif
 
-
 /* check result and die, printing the offending address and error */
 void check_res_dumpdie(int res, struct addrinfo *addr, char* syscall)
 {
@@ -60,7 +61,7 @@ int start_listen_sockets(int *sockfd[], struct addrinfo *addr_list)
 {
    struct sockaddr_storage *saddr;
    struct addrinfo *addr;
-   int i, res, reuse;
+   int i, res, one;
    int num_addr = 0;
 
    for (addr = addr_list; addr; addr = addr->ai_next)
@@ -81,9 +82,14 @@ int start_listen_sockets(int *sockfd[], struct addrinfo *addr_list)
        (*sockfd)[i] = socket(saddr->ss_family, SOCK_STREAM, 0);
        check_res_dumpdie((*sockfd)[i], addr, "socket");
 
-       reuse = 1;
-       res = setsockopt((*sockfd)[i], SOL_SOCKET, SO_REUSEADDR, (char*)&reuse, sizeof(reuse));
-       check_res_dumpdie(res, addr, "setsockopt");
+       one = 1;
+       res = setsockopt((*sockfd)[i], SOL_SOCKET, SO_REUSEADDR, (char*)&one, sizeof(one));
+       check_res_dumpdie(res, addr, "setsockopt(SO_REUSEADDR)");
+
+       if (IP_FREEBIND) {
+           res = setsockopt((*sockfd)[i], IPPROTO_IP, IP_FREEBIND, (char*)&one, sizeof(one));
+           check_res_dumpdie(res, addr, "setsockopt(IP_FREEBIND)");
+       }
 
        res = bind((*sockfd)[i], addr->ai_addr, addr->ai_addrlen);
        check_res_dumpdie(res, addr, "bind");
@@ -96,27 +102,59 @@ int start_listen_sockets(int *sockfd[], struct addrinfo *addr_list)
    return num_addr;
 }
 
+/* Transparent proxying: bind the peer address of fd to the peer address of
+ * fd_from */
+#define IP_TRANSPARENT 19
+int bind_peer(int fd, int fd_from)
+{
+    struct addrinfo from;
+    struct sockaddr_storage ss;
+    int res, trans = 1;
+
+    memset(&from, 0, sizeof(from));
+    from.ai_addr = (struct sockaddr*)&ss;
+    from.ai_addrlen = sizeof(ss);
+
+    /* getpeername can fail with ENOTCONN if connection was dropped before we
+     * got here */
+    res = getpeername(fd_from, from.ai_addr, &from.ai_addrlen);
+    CHECK_RES_RETURN(res, "getpeername");
+    res = setsockopt(fd, IPPROTO_IP, IP_TRANSPARENT, &trans, sizeof(trans));
+    CHECK_RES_DIE(res, "setsockopt");
+    res = bind(fd, from.ai_addr, from.ai_addrlen);
+    CHECK_RES_RETURN(res, "bind");
+
+    return 0;
+}
+
 /* Connect to first address that works and returns a file descriptor, or -1 if
- * none work. cnx_name points to the name of the service (for logging) */
-int connect_addr(struct addrinfo *addr, const char* cnx_name)
+ * 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;
     char buf[NI_MAXHOST];
     int fd, res;
 
-    for (a = addr; a; a = a->ai_next) {
+    for (a = cnx->proto->saddr; a; a = a->ai_next) {
         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);
         fd = socket(a->ai_family, SOCK_STREAM, 0);
         if (fd == -1) {
-            log_message(LOG_ERR, "forward to %s failed:socket: %s\n", cnx_name, strerror(errno));
+            log_message(LOG_ERR, "forward to %s failed:socket: %s\n",
+                        cnx->proto->description, strerror(errno));
         } else {
+            if (transparent) {
+                res = bind_peer(fd, fd_from);
+                CHECK_RES_RETURN(res, "bind_peer");
+            }
             res = connect(fd, a->ai_addr, a->ai_addrlen);
             if (res == -1) {
                 log_message(LOG_ERR, "forward to %s failed:connect: %s\n", 
-                            cnx_name, strerror(errno));
+                            cnx->proto->description, strerror(errno));
             } else {
                 return fd;
             }
@@ -128,12 +166,20 @@ int connect_addr(struct addrinfo *addr, const char* cnx_name)
 /* Store some data to write to the queue later */
 int defer_write(struct queue *q, void* data, int data_size) 
 {
+    char *p;
     if (verbose) 
-        fprintf(stderr, "**** writing defered on fd %d\n", q->fd);
-    q->defered_data = malloc(data_size);
-    q->begin_defered_data = q->defered_data;
-    q->defered_data_size = data_size;
-    memcpy(q->defered_data, data, data_size);
+        fprintf(stderr, "**** writing deferred on fd %d\n", q->fd);
+
+    p = realloc(q->begin_deferred_data, 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->deferred_data_size += data_size;
+    memcpy(p, data, data_size);
 
     return 0;
 }
@@ -142,30 +188,29 @@ int defer_write(struct queue *q, void* data, int data_size)
  * Upon success, the number of bytes written is returned.
  * Upon failure, -1 returned (e.g. connexion closed)
  * */
-int flush_defered(struct queue *q)
+int flush_deferred(struct queue *q)
 {
     int n;
 
     if (verbose)
-        fprintf(stderr, "flushing defered data to fd %d\n", q->fd);
+        fprintf(stderr, "flushing deferred data to fd %d\n", q->fd);
 
-    n = write(q->fd, q->defered_data, q->defered_data_size);
+    n = write(q->fd, q->deferred_data, q->deferred_data_size);
     if (n == -1)
         return n;
 
-    if (n == q->defered_data_size) {
+    if (n == q->deferred_data_size) {
         /* All has been written -- release the memory */
-        free(q->begin_defered_data);
-        q->begin_defered_data = NULL;
-        q->defered_data = NULL;
-        q->defered_data_size = 0;
+        free(q->begin_deferred_data);
+        q->begin_deferred_data = NULL;
+        q->deferred_data = NULL;
+        q->deferred_data_size = 0;
     } else {
         /* There is data left */
-        q->defered_data += n;
-        q->defered_data_size -= n;
+        q->deferred_data += n;
+        q->deferred_data_size -= n;
     }
 
-
     return n;
 }
 
@@ -175,26 +220,25 @@ void init_cnx(struct connection *cnx)
     memset(cnx, 0, sizeof(*cnx));
     cnx->q[0].fd = -1;
     cnx->q[1].fd = -1;
+    cnx->proto = get_first_protocol();
 }
 
 void dump_connection(struct connection *cnx)
 {
     printf("state: %d\n", cnx->state);
-    printf("fd %d, %d defered\n", cnx->q[0].fd, cnx->q[0].defered_data_size);
-    printf("fd %d, %d defered\n", cnx->q[1].fd, cnx->q[1].defered_data_size);
+    printf("fd %d, %d deferred\n", cnx->q[0].fd, cnx->q[0].deferred_data_size);
+    printf("fd %d, %d deferred\n", cnx->q[1].fd, cnx->q[1].deferred_data_size);
 }
 
 
 /* 
  * moves data from one fd to other
  *
- * retuns number of bytes copied if success
+ * returns number of bytes copied if success
  * returns 0 (FD_CNXCLOSED) if incoming socket closed
  * returns FD_NODATA if no data was available
  * returns FD_STALLED if data was read, could not be written, and has been
  * stored in temporary buffer.
- *
- * slot for debug only and may go away at some point
  */
 int fd2fd(struct queue *target_q, struct queue *from_q)
 {
@@ -225,7 +269,7 @@ int fd2fd(struct queue *target_q, struct queue *from_q)
 
    size_w = write(target, buffer, size_r);
    /* process -1 when we know how to deal with it */
-   if ((size_w == -1)) {
+   if (size_w == -1) {
        switch (errno) {
        case EAGAIN:
            /* write blocked: Defer data */
@@ -354,7 +398,8 @@ void log_connection(struct connection *cnx)
     addr.ai_addrlen = sizeof(ss);
 
     res = getpeername(cnx->q[0].fd, addr.ai_addr, &addr.ai_addrlen);
-    if (res == -1) return; /* that should never happen, right? */
+    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);
 
     addr.ai_addrlen = sizeof(ss);
@@ -395,7 +440,7 @@ int check_access_rights(int in_socket, const char* service)
     int res;
 
     res = getpeername(in_socket, &peeraddr, &size);
-    CHECK_RES_DIE(res, "getpeername");
+    CHECK_RES_RETURN(res, "getpeername");
 
     /* extract peer address */
     res = getnameinfo(&peeraddr, size, addr_str, sizeof(addr_str), NULL, 0, NI_NUMERICHOST);
@@ -438,7 +483,7 @@ void setup_signals(void)
     res = sigaction(SIGCHLD, &action, NULL);
     CHECK_RES_DIE(res, "sigaction");
 
-    /* Set SIGTERM to exit. For some reason if it's not set explicitely,
+    /* Set SIGTERM to exit. For some reason if it's not set explicitly,
      * coverage information is lost when killing the process */
     memset(&action, 0, sizeof(action));
     action.sa_handler = exit;
@@ -456,9 +501,11 @@ void setup_signals(void)
  * banner is made up of basename(bin_name)+"[pid]" */
 void setup_syslog(const char* bin_name) {
     char *name1, *name2;
+    int res;
 
     name1 = strdup(bin_name);
-    asprintf(&name2, "%s[%d]", basename(name1), getpid());
+    res = asprintf(&name2, "%s[%d]", basename(name1), getpid());
+    CHECK_RES_DIE(res, "asprintf");
     openlog(name2, LOG_CONS, LOG_AUTH);
     free(name1); 
     /* Don't free name2, as openlog(3) uses it (at least in glibc) */
@@ -466,7 +513,57 @@ void setup_syslog(const char* bin_name) {
     log_message(LOG_INFO, "%s %s started\n", server_type, VERSION);
 }
 
-/* We don't want to run as root -- drop priviledges if required */
+/* Ask OS to keep capabilities over a setuid(nonzero) */
+void set_keepcaps(int val) {
+#ifdef LIBCAP
+    int res;
+    res = prctl(PR_SET_KEEPCAPS, val, 0, 0, 0);
+    if (res) {
+        perror("prctl");
+        exit(1);
+    }
+#endif
+}
+
+/* set needed capabilities for effective and permitted, clear rest */
+void set_capabilities(void) {
+#ifdef LIBCAP
+    int res;
+    cap_t caps;
+    cap_value_t cap_list[10];
+    int ncap = 0;
+
+    if (transparent)
+        cap_list[ncap++] = CAP_NET_ADMIN;
+
+    caps = cap_init();
+
+#define _cap_set_flag(flag) do { \
+        res = cap_clear_flag(caps, flag); \
+        CHECK_RES_DIE(res, "cap_clear_flag(" #flag ")"); \
+        if (ncap > 0) { \
+            res = cap_set_flag(caps, flag, ncap, cap_list, CAP_SET); \
+            CHECK_RES_DIE(res, "cap_set_flag(" #flag ")"); \
+        } \
+    } while(0)
+
+    _cap_set_flag(CAP_EFFECTIVE);
+    _cap_set_flag(CAP_PERMITTED);
+
+#undef _cap_set_flag
+
+    res = cap_set_proc(caps);
+    CHECK_RES_DIE(res, "cap_set_proc");
+
+    res = cap_free(caps);
+    if (res) {
+        perror("cap_free");
+        exit(1);
+    }
+#endif
+}
+
+/* We don't want to run as root -- drop privileges if required */
 void drop_privileges(const char* user_name)
 {
     int res;
@@ -478,10 +575,15 @@ void drop_privileges(const char* user_name)
     if (verbose)
         fprintf(stderr, "turning into %s\n", user_name);
 
+    set_keepcaps(1);
+
     res = setgid(pw->pw_gid);
     CHECK_RES_DIE(res, "setgid");
-    setuid(pw->pw_uid);
+    res = setuid(pw->pw_uid);
     CHECK_RES_DIE(res, "setuid");
+
+    set_capabilities();
+    set_keepcaps(0);
 }
 
 /* Writes my PID */

common.h

@@ -1,6 +1,12 @@
 #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)
+ */
+#ifdef __CYGWIN__
+#define FD_SETSIZE 4096
+#endif
 
 #define _GNU_SOURCE
 #include <sys/types.h>
@@ -22,10 +28,13 @@
 #include <time.h>
 #include <getopt.h>
 
-#ifndef VERSION
-#define VERSION "v?"
+#ifdef LIBCAP
+#include <sys/prctl.h>
+#include <sys/capability.h>
 #endif
 
+#include "version.h"
+
 #define CHECK_RES_DIE(res, str) \
     if (res == -1) {    \
        perror(str);     \
@@ -34,7 +43,7 @@
 
 #define CHECK_RES_RETURN(res, str) \
     if (res == -1) {                                    \
-        log_message(LOG_CRIT, "%s: %d\n", str, errno);  \
+        log_message(LOG_CRIT, "%s:%d:%s\n", str, errno, strerror(errno));  \
         return res;                                     \
     } 
 
@@ -46,6 +55,10 @@
 #define TRACE
 #endif
 
+#ifndef IP_FREEBIND
+#define IP_FREEBIND 0
+#endif
+
 enum connection_state {
     ST_PROBING=1,    /* Waiting for timeout to find where to forward */
     ST_SHOVELING   /* Connexion is established */
@@ -55,17 +68,18 @@ enum connection_state {
 #define PROT_SHIFT 1000  /* protocol options will be 1000, 1001, etc */
 
 /* A 'queue' is composed of a file descriptor (which can be read from or
- * written to), and a queue for defered write data */
+ * written to), and a queue for deferred write data */
 struct queue {
     int fd;
-    void *begin_defered_data;
-    void *defered_data;
-    int defered_data_size;
+    void *begin_deferred_data;
+    void *deferred_data;
+    int deferred_data_size;
 };
 
 struct connection {
     enum connection_state state;
     time_t probe_timeout;
+    struct proto *proto;
 
     /* q[0]: queue for external connection (client);
      * q[1]: queue for internal connection (httpd or sshd);
@@ -80,11 +94,10 @@ struct connection {
 
 /* common.c */
 void init_cnx(struct connection *cnx);
-int connect_addr(struct addrinfo *addr, const char* cnx_name);
+int connect_addr(struct connection *cnx, int fd_from);
 int fd2fd(struct queue *target, struct queue *from);
 char* sprintaddr(char* buf, size_t size, struct addrinfo *a);
 void resolve_name(struct addrinfo **out, char* fullname);
-struct proto* probe_client_protocol(struct connection *cnx);
 void log_connection(struct connection *cnx);
 int check_access_rights(int in_socket, const char* service);
 void setup_signals(void);
@@ -98,13 +111,14 @@ int resolve_split_name(struct addrinfo **out, const char* hostname, const char*
 int start_listen_sockets(int *sockfd[], struct addrinfo *addr_list);
 
 int defer_write(struct queue *q, void* data, int data_size);
-int flush_defered(struct queue *q);
+int flush_deferred(struct queue *q);
 
-extern int probing_timeout, verbose, inetd, foreground, background, numeric;
+extern int probing_timeout, verbose, inetd, foreground, 
+       background, transparent, numeric;
 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, *rule_filename;
+extern const char* user_name, *pid_file;
 extern const char* server_type;
 
 /* sslh-fork.c */

echosrv.c

@@ -94,32 +94,26 @@ void parse_cmdline(int argc, char* argv[])
 
 void start_echo(int fd)
 {
-    fd_set fds;
     int res;
     char buffer[1 << 20];
-    char* ret;
-    FILE *socket;
+    int ret, prefix_len;
 
-    FD_ZERO(&fds);
+    prefix_len = strlen(prefix);
 
-    socket = fdopen(fd, "r+");
-    if (!socket) {
-        CHECK_RES_DIE(-1, "fdopen");
-    }
+    memset(buffer, 0, sizeof(buffer));
+    strcpy(buffer, prefix);
 
     while (1) {
-        ret = fgets(buffer, sizeof(buffer), socket);
-        if (!ret) {
-            fprintf(stderr, "%s", strerror(ferror(socket)));
+        ret = read(fd, buffer + prefix_len, sizeof(buffer));
+        if (ret == -1) {
+            fprintf(stderr, "%s", strerror(errno));
             return;
         }
-        res = fprintf(socket, "%s%s", prefix, buffer);
+        res = write(fd, buffer, ret + prefix_len);
         if (res < 0) {
-            fprintf(stderr, "%s", strerror(ferror(socket)));
+            fprintf(stderr, "%s", strerror(errno));
             return;
         }
-
-        fflush(socket);
     }
 }
 

example.cfg

@@ -1,7 +1,13 @@
-verbose: false;
+# This file is provided as documentation to show what is
+# possible. It should not be used as-is, and probably should
+# not be used as a starting point for a working
+# configuration. Instead use basic.cfg.
+
+verbose: true;
 foreground: true;
 inetd: false;
 numeric: false;
+transparent: false;
 timeout: 2;
 user: "nobody";
 pidfile: "/var/run/sslh.pid";
@@ -10,8 +16,8 @@ pidfile: "/var/run/sslh.pid";
 # List of interfaces on which we should listen
 listen:
 (
-    { host: "thelonious"; port: "443"; }
-#    , { host: "thelonious"; port: "8080"; }
+    { host: "thelonious"; port: "443"; },
+    { host: "thelonious"; port: "8080"; }
 );
 
 # List of protocols
@@ -22,10 +28,8 @@ listen:
 #   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)
 #   
-# In case of timeout sslh will connect to the first
-# protocol: this should be SSH.
-# SSL should have a "always true" probe, and come last.
 # sslh will try each probe in order they are declared, and
 # connect to the first that matches.
 
@@ -35,6 +39,15 @@ protocols:
      { 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: "ssl"; host: "localhost"; port: "443"; probe: [ "" ]; },
+     { 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.
+# This enables you to set a tcpd service name for this
+# protocol too.
+on-timeout: "timeout";
+

genver.sh

@@ -0,0 +1,40 @@
+#! /bin/bash
+
+if [ ${#} -eq 1 ] && [ "x$1" = "x-r" ]; then
+	# release text only
+	QUIET=1
+else
+	QUIET=0
+fi
+
+if ! `(git status | grep -q "On branch") 2> /dev/null`; then
+        # If we don't have git, we can't work out what
+        # version this is. It must have been downloaded as a
+        # zip file. Github creates the zip file with all
+        # files dated from the last change: use the
+        # Makefile's modification time as a release number
+	release=zip-`stat -c "%y" Makefile | sed 's/ .*//'`
+fi
+
+if head=`git rev-parse --verify HEAD 2>/dev/null`; then
+	# generate the version info based on the tag
+	release=`(git describe --tags || git --describe || git describe --all --long) \
+		2>/dev/null | tr -d '\n'`
+
+	# Are there uncommitted changes?
+	git update-index --refresh --unmerged > /dev/null
+	if git diff-index --name-only HEAD | grep -v "^scripts/package" \
+	    | read dummy; then
+		release="$release-dirty"
+	fi
+fi
+
+
+if [ $QUIET -ne 1 ]; then
+	printf "#ifndef _VERSION_H_ \n"
+	printf "#define _VERSION_H_ \n\n"
+	printf "#define VERSION \"$release\"\n"
+	printf "#endif\n"
+else
+	printf "$release\n"
+fi

probe.c

@@ -19,7 +19,10 @@
 # http://www.gnu.org/licenses/gpl.html
 */
 
+#define _GNU_SOURCE
+#include <stdio.h>
 #include <regex.h>
+#include <ctype.h>
 #include "probe.h"
 
 
@@ -29,6 +32,7 @@ static int is_openvpn_protocol(const char *p, int len, struct proto*);
 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_true(const char *p, int len, struct proto* proto) { return 1; }
 
 /* Table of protocols that have a built-in probe
@@ -40,10 +44,13 @@ static struct proto builtins[] = {
     { "tinc",        NULL,     NULL,   is_tinc_protocol },
     { "xmpp",        NULL,     NULL,   is_xmpp_protocol },
     { "http",        NULL,     NULL,   is_http_protocol },
-    { "ssl",          NULL,     NULL,  is_true }
+    { "ssl",         NULL,     NULL,   is_tls_protocol },
+    { "tls",         NULL,     NULL,   is_tls_protocol },
+    { "anyprot",     NULL,     NULL,   is_true }
 };
 
 static struct proto *protocols;
+static char* on_timeout = "ssh";
 
 struct proto*  get_builtins(void) {
     return builtins;
@@ -53,12 +60,22 @@ int get_num_builtins(void) {
     return ARRAY_SIZE(builtins);
 }
 
-/* Returns the protocol to connect to in case of timeout; conventionaly this is
- * the first protocol specified (but maybe we'll make it more explicit some
- * day)
+/* Sets the protocol name to connect to in case of timeout */
+void set_ontimeout(const char* name)
+{
+    int res = asprintf(&on_timeout, "%s", name);
+    CHECK_RES_DIE(res, "asprintf");
+}
+
+/* Returns the protocol to connect to in case of timeout; 
+ * if not found, return the first protocol specified 
  */
-struct proto* timeout_protocol(void) {
-    return protocols;
+struct proto* timeout_protocol(void) 
+{
+    struct proto* p = get_first_protocol();
+    for (; p && strcmp(p->description, on_timeout); p = p->next);
+    if (p) return p;
+    return get_first_protocol();
 }
 
 /* returns the first protocol (caller can then follow the *next pointers) */
@@ -72,34 +89,67 @@ void set_protocol_list(struct proto* prots)
     protocols = prots;
 }
 
+/* From http://grapsus.net/blog/post/Hexadecimal-dump-in-C */
+#define HEXDUMP_COLS 16
+void hexdump(const char *mem, unsigned int len)
+{
+    unsigned int i, j;
+
+    for(i = 0; i < len + ((len % HEXDUMP_COLS) ? (HEXDUMP_COLS - len % HEXDUMP_COLS) : 0); i++)
+    {
+        /* print offset */
+        if(i % HEXDUMP_COLS == 0)
+            printf("0x%06x: ", i);
+
+        /* print hex data */
+        if(i < len)
+            printf("%02x ", 0xFF & mem[i]);
+        else /* end of block, just aligning for ASCII dump */
+            printf("   ");
+
+        /* 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(' ');
+                else if(isprint(mem[j])) /* printable char */
+                    putchar(0xFF & mem[j]);        
+                else /* other char */
+                    putchar('.');
+            }
+            putchar('\n');
+        }
+    }
+}
+
 /* Is the buffer the beginning of an SSH connection? */
 static int is_ssh_protocol(const char *p, int len, struct proto *proto)
 {
-    if (!strncmp(p, "SSH-", 4)) {
-        return 1;
-    }
-    return 0;
+    if (len < 4)
+        return PROBE_AGAIN;
+
+    return !strncmp(p, "SSH-", 4);
 }
 
 /* Is the buffer the beginning of an OpenVPN connection?
- * (code lifted from OpenVPN port-share option)
+ *
+ * Code inspired from OpenVPN port-share option; however, OpenVPN code is
+ * wrong: users using pre-shared secrets have non-initialised key_id fields so
+ * p[3] & 7 should not be looked at, and also the key_method can be specified
+ * to 1 which changes the opcode to P_CONTROL_HARD_RESET_CLIENT_V1.
+ * See:
+ * http://www.fengnet.com/book/vpns%20illustrated%20tunnels%20%20vpnsand%20ipsec/ch08lev1sec5.html
+ * and OpenVPN ssl.c, ssl.h and options.c
  */
 static int is_openvpn_protocol (const char*p,int len, struct proto *proto)
 {
-#define P_OPCODE_SHIFT                 3
-#define P_CONTROL_HARD_RESET_CLIENT_V2 7
-    if (len >= 3)
-    {
-        return p[0] == 0
-            && p[1] >= 14
-            && p[2] == (P_CONTROL_HARD_RESET_CLIENT_V2<<P_OPCODE_SHIFT);
-    }
-    else if (len >= 2)
-    {
-        return p[0] == 0 && p[1] >= 14;
-    }
-    else
-        return 0;
+    int packet_len;
+
+    if (len < 2)
+        return PROBE_AGAIN;
+
+    packet_len = ntohs(*(uint16_t*)p);
+    return packet_len == len - 2;
 }
 
 /* Is the buffer the beginning of a tinc connections?
@@ -107,6 +157,9 @@ static int is_openvpn_protocol (const char*p,int len, struct proto *proto)
  * */
 static int is_tinc_protocol( const char *p, int len, struct proto *proto)
 {
+    if (len < 2)
+        return PROBE_AGAIN;
+
     return !strncmp(p, "0 ", 2);
 }
 
@@ -116,57 +169,76 @@ 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)
 {
-    return strstr(p, "jabber") ? 1 : 0;
+    if (len < 6)
+        return PROBE_AGAIN;
+
+    return memmem(p, len, "jabber", 6) ? 1 : 0;
 }
 
-static int probe_http_method(const char *p, const char *opt)
+static int probe_http_method(const char *p, int len, const char *opt)
 {
-    return !strcmp(p, opt);
+    if (len < strlen(opt))
+        return PROBE_AGAIN;
+
+    return !strncmp(p, opt, len);
 }
 
 /* Is the buffer the beginning of an HTTP connection?  */
 static int is_http_protocol(const char *p, int len, struct proto *proto)
 {
+    int res;
     /* If it's got HTTP in the request (HTTP/1.1) then it's HTTP */
-    if (strstr(p, "HTTP"))
-        return 1;
+    if (memmem(p, len, "HTTP", 4))
+        return PROBE_MATCH;
+
+#define PROBE_HTTP_METHOD(opt) if ((res = probe_http_method(p, len, opt)) != PROBE_NEXT) return res
 
     /* Otherwise it could be HTTP/1.0 without version: check if it's got an
      * HTTP method (RFC2616 5.1.1) */
-    probe_http_method(p, "OPTIONS");
-    probe_http_method(p, "GET");
-    probe_http_method(p, "HEAD");
-    probe_http_method(p, "POST");
-    probe_http_method(p, "PUT");
-    probe_http_method(p, "DELETE");
-    probe_http_method(p, "TRACE");
-    probe_http_method(p, "CONNECT");
+    PROBE_HTTP_METHOD("OPTIONS");
+    PROBE_HTTP_METHOD("GET");
+    PROBE_HTTP_METHOD("HEAD");
+    PROBE_HTTP_METHOD("POST");
+    PROBE_HTTP_METHOD("PUT");
+    PROBE_HTTP_METHOD("DELETE");
+    PROBE_HTTP_METHOD("TRACE");
+    PROBE_HTTP_METHOD("CONNECT");
 
-    return 0;
+#undef PROBE_HTTP_METHOD
+
+    return PROBE_NEXT;
 }
 
+static int is_tls_protocol(const char *p, int len, struct proto *proto)
+{
+    if (len < 3)
+        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)
+     */
+    return p[0] == 0x16 && p[1] == 0x03 && ( p[2] >= 0 && p[2] <= 0x03);
+}
 
 static int regex_probe(const char *p, int len, struct proto *proto)
 {
-    regex_t** probe_list = (regex_t**)(proto->data);
-    int i=0;
+    regex_t **probe = proto->data;
+    regmatch_t pos = { 0, len };
 
-    while (probe_list[i]) {
-        if (!regexec(probe_list[i], p, 0, NULL, 0)) {
-            return 1;
-        }
-        i++;
-    }
-    return 0;
+    for (; *probe && regexec(*probe, p, 0, &pos, REG_STARTEND); probe++)
+        /* try them all */;
+
+    return (probe != NULL);
 }
 
 /* 
  * Read the beginning of data coming from the client connection and check if
- * it's a known protocol. Then leave the data on the defered
- * write buffer of the connection and returns a pointer to the protocol
- * structure
+ * it's a known protocol. 
+ * Return PROBE_AGAIN if not enough data, or PROBE_MATCH if it succeeded in
+ * which case cnx->proto is set to the appropriate protocol.
  */
-struct proto* probe_client_protocol(struct connection *cnx)
+int probe_client_protocol(struct connection *cnx)
 {
     char buffer[BUFSIZ];
     struct proto *p;
@@ -179,31 +251,54 @@ struct proto* probe_client_protocol(struct connection *cnx)
      * function does not have to deal with a specific  failure condition (the
      * connection will just fail later normally). */
     if (n > 0) {
+        int res = PROBE_NEXT;
+
         defer_write(&cnx->q[1], buffer, n);
 
-        for (p = protocols; p; p = p->next) {
-            if (p->probe(buffer, n, p)) {
-                return p;
-            }
+        for (p = cnx->proto; p && res == PROBE_NEXT; p = p->next) {
+            if (! p->probe) continue;
+            if (verbose) fprintf(stderr, "probing for %s\n", p->description);
+
+            cnx->proto = p;
+            res = p->probe(cnx->q[1].begin_deferred_data, cnx->q[1].deferred_data_size, p);
         }
+        if (res != PROBE_NEXT)
+            return res;
     }
 
+    if (verbose) 
+        fprintf(stderr, 
+                "all probes failed, connecting to first protocol: %s\n", 
+                protocols->description);
+
     /* If none worked, return the first one affected (that's completely
      * arbitrary) */
-    return protocols;
+    cnx->proto = protocols;
+    return PROBE_MATCH;
+}
+
+/* Returns the structure for specified protocol or NULL if not found */
+static struct proto* get_protocol(const char* description)
+{
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(builtins); i++) {
+        if (!strcmp(builtins[i].description, description)) {
+            return &builtins[i];
+        }
+    }
+    return NULL;
 }
 
 /* Returns the probe for specified protocol:
  * parameter is the description in builtins[], or "regex" 
  * */
 T_PROBE* get_probe(const char* description) {
-    int i;
+    struct proto* p = get_protocol(description);
+
+    if (p)
+        return p->probe;
 
-    for (i = 0; i < ARRAY_SIZE(builtins); i++) {
-        if (!strcmp(builtins[i].description, description)) {
-            return builtins[i].probe;
-        }
-    }
     /* Special case of "regex" probe (we don't want to set it in builtins
      * because builtins is also used to build the command-line options and
      * regexp is not legal on the command line)*/

probe.h

@@ -5,6 +5,12 @@
 
 #include "common.h"
 
+typedef enum {
+    PROBE_NEXT,  /* Enough data, probe failed -- it's some other protocol */
+    PROBE_MATCH, /* Enough data, probe successful -- it's the current protocol */
+    PROBE_AGAIN, /* Not enough data for this probe, try again with more data */
+} probe_result;
+
 struct proto;
 typedef int T_PROBE(const char*, int, struct proto*);
 
@@ -39,11 +45,14 @@ void set_protocol_list(struct proto*);
 /* probe_client_protocol
  *
  * Read the beginning of data coming from the client connection and check if
- * it's a known protocol. Then leave the data on the defered
+ * it's a known protocol. Then leave the data on the deferred
  * write buffer of the connection and returns a pointer to the protocol
  * structure
  */
-struct proto* probe_client_protocol(struct connection *cnx);
+int probe_client_protocol(struct connection *cnx);
+
+/* set the protocol to connect to in case of timeout */
+void set_ontimeout(const char* name);
 
 /* timeout_protocol
  *
@@ -51,4 +60,6 @@ struct proto* probe_client_protocol(struct connection *cnx);
  */
 struct proto* timeout_protocol(void);
 
+void hexdump(const char*, unsigned int);
+
 #endif

scripts/etc.init.d.sslh

@@ -2,6 +2,8 @@
 
 ### BEGIN INIT INFO
 # Provides:		sslh
+# Required-Start:    $remote_fs $syslog
+# Required-Stop:     $remote_fs $syslog
 # Default-Start:	2 3 4 5
 # Default-Stop:		1
 # Short-Description:	sslh proxy ssl & ssh connections

scripts/etc.rc.d.init.d.sslh.centos

@@ -1,56 +1,56 @@
 #!/bin/bash
 #
-#       /etc/rc.d/init.d/sslh
-# sslh          This shell script takes care of starting and stopping
-#               sslh - a daemon switching incoming connection between SSH and SSL/HTTPS servers
+# sslh         Startup script for the SSL/SSH multiplexer
 #
-# Author: Andre Krajnik akrajnik@gmail.com
-# 2010-03-20
+# chkconfig: - 13 87
+# description: Sslh accepts connections on specified ports, and forwards
+#              them further based on tests performed on the first data
+#              packet sent by the remote client.
+# processname: sslh
+# config: /etc/sslh.cfg
+# config: /etc/sysconfig/sslh
+# pidfile: /var/run/sslh/sslh.pid
 #
-#
-# chkconfig: 2345 13 87
-#
-# description: sslh - a daemon switching incoming connection between SSH and SSL/HTTPS servers
+# Authors:
+# Andre Krajnik akrajnik@gmail.com - 2010-03-20
+# Julien Thomas julthomas@free.fr - 2013-08-25
 
 # Source function library.
 . /etc/init.d/functions
 
-# ./sslh -p  0.0.0.0:8443 -l 127.0.0.1:443 -s 127.0.0.1:22
-
-SSLH="/usr/local/sbin/sslh"
-PIDFILE="/var/run/sslh"
-
-OPTIONS="--user nobody --pidfile $PIDFILE -p  0.0.0.0:8443 --ssl 127.0.0.1:443 --ssh 127.0.0.1:22"
-
 if [ -f /etc/sysconfig/sslh ]; then
         . /etc/sysconfig/sslh
 fi
 
-start() {
-        echo -n "Starting SSL-SSH-Switch: "
-        if [ -f $PIDFILE ]; then
-                PID=`cat $PIDFILE`
-                echo sslh already running: $PID
-                exit 2;
-        else
-                daemon  $SSLH $OPTIONS
-                RETVAL=$?
-                echo
-                [ $RETVAL -eq 0 ] && touch $PIDFILE
-                return $RETVAL
-        fi
+PROGNAME=sslh
+SSLH=${SSLH:-/usr/sbin/sslh-select}
+SSLH_LANG=${SSLH_LANG:-C}
+CONFIG=${CONFIG:-/etc/sslh.cfg}
+PIDFILE=${PIDFILE:-/var/run/sslh/sslh.pid}
+LOCKFILE=${LOCKFILE:-/var/lock/subsys/sslh}
+STOP_TIMEOUT=${STOP_TIMEOUT:-10}
+RETVAL=0
 
+start() {
+    echo -n "Starting $PROGNAME: "
+    LANG=$SSLH_LANG daemon --pidfile="$PIDFILE" \
+                           ${SSLH_USER:+--user="${SSLH_USER}"} \
+                           "$SSLH" ${CONFIG:+-F "$CONFIG"} "$OPTIONS"
+    RETVAL=$?
+    echo
+    [ $RETVAL = 0 ] && touch "$LOCKFILE"
+    return $RETVAL
 }
 
 stop() {
-        echo -n "Shutting down SSL-SSH-Switch: "
-        echo
-        killproc sslh
-        echo
-        rm -f $PIDFILE
-        return 0
+    echo -n "Stopping $PROGNAME: "
+    killproc -p "$PIDFILE" -d "$STOP_TIMEOUT" "$SSLH"
+    RETVAL=$?
+    echo
+    [ $RETVAL = 0 ] && rm -f "$LOCKFILE" "$PIDFILE"
 }
 
+# See how we were called.
 case "$1" in
     start)
         start
@@ -59,18 +59,17 @@ case "$1" in
         stop
         ;;
     status)
-        status sslh
+        status -p "$PIDFILE" "$SSLH"
+        RETVAL=$?
         ;;
     restart)
         stop
         start
         ;;
     *)
-        echo "Usage:  {start|stop|status|restart}"
-        exit 1
+        echo "Usage: $PROGNAME {start|stop|status|restart}"
+        RETVAL=2
         ;;
 esac
-exit $?
-
-
 
+exit $RETVAL

scripts/etc.sysconfig.sslh

@@ -0,0 +1,36 @@
+#
+# The default processing model uses select
+# A fork model is also available
+#
+#SSLH=/usr/sbin/sslh-select
+
+#
+# If transparent mode is enabled, the following
+# is needed in order to run as sslh user
+#
+#SSLH_USER=sslh
+#setcap cap_net_bind_service,cap_net_admin=+ep $SSLH
+
+#
+# Configuration file for sslh
+# Set empty to disable configuration file support
+#
+#CONFIG=/etc/sslh.cfg
+
+#
+# Extra option to pass on comand line
+# Those can supersede configuration file settings
+# 
+#OPTIONS=
+
+#
+# The sslh process is started by default with the C
+# locale, it can be changed here
+#
+#SSLH_LANG=C
+
+#
+# If an alternate location is specified in configuration
+# file, it needs to be reported here
+#
+#PIDFILE=/var/run/sslh/sslh.pid

scripts/systemd.sslh.service

@@ -1,9 +1,11 @@
 [Unit]
 Description=SSL/SSH multiplexer
+After=network.target
 
 [Service]
 EnvironmentFile=/etc/conf.d/sslh
 ExecStart=/usr/bin/sslh --foreground $DAEMON_OPTS
+KillMode=process
 
 [Install]
 WantedBy=multi-user.target

sslh-fork.c

@@ -69,47 +69,49 @@ void start_shoveler(int in_socket)
 {
    fd_set fds;
    struct timeval tv;
-   struct addrinfo *saddr;
-   int res;
+   int res = PROBE_AGAIN;
    int out_socket;
    struct connection cnx;
-   struct proto *prot;
 
    init_cnx(&cnx);
+   cnx.q[0].fd = in_socket;
 
    FD_ZERO(&fds);
    FD_SET(in_socket, &fds);
    memset(&tv, 0, sizeof(tv));
    tv.tv_sec = probing_timeout;
-   res = select(in_socket + 1, &fds, NULL, NULL, &tv);
-   if (res == -1)
-      perror("select");
 
-   cnx.q[0].fd = in_socket;
+   while (res == PROBE_AGAIN) {
+       /* POSIX does not guarantee that tv will be updated, but the client can
+        * only postpone the inevitable for so long */
+       res = select(in_socket + 1, &fds, NULL, NULL, &tv);
+       if (res == -1)
+           perror("select");
 
-   if (FD_ISSET(in_socket, &fds)) {
-       /* Received data: figure out what protocol it is */
-       prot = probe_client_protocol(&cnx);
-   } else {
-       /* Timed out: it's necessarily SSH */
-       prot = timeout_protocol();
+       if (FD_ISSET(in_socket, &fds)) {
+           /* Received data: figure out what protocol it is */
+           res = probe_client_protocol(&cnx);
+       } else {
+           /* Timed out: it's necessarily SSH */
+           cnx.proto = timeout_protocol();
+           break;
+       }
    }
 
-   saddr = prot->saddr;
-   if (prot->service && 
-       check_access_rights(in_socket, prot->service)) {
+   if (cnx.proto->service &&
+       check_access_rights(in_socket, cnx.proto->service)) {
        exit(0);
    }
 
    /* Connect the target socket */
-   out_socket = connect_addr(saddr, prot->description);
+   out_socket = connect_addr(&cnx, in_socket);
    CHECK_RES_DIE(out_socket, "connect");
 
    cnx.q[1].fd = out_socket;
 
    log_connection(&cnx);
 
-   flush_defered(&cnx.q[1]);
+   flush_deferred(&cnx.q[1]);
 
    shovel(&cnx);
 
@@ -155,7 +157,8 @@ void main_loop(int listen_sockets[], int num_addr_listen)
 
                 if (!fork())
                 {
-                    close(listen_sockets[i]);
+                    for (i = 0; i < num_addr_listen; ++i)
+                        close(listen_sockets[i]);
                     start_shoveler(in_socket);
                     exit(0);
                 }

sslh-main.c

@@ -36,12 +36,14 @@ const char* USAGE_STRING =
 "\tsslh  [-v] [-i] [-V] [-f] [-n] [-F <file>]\n"
 "\t[-t <timeout>] [-P <pidfile>] -u <username> -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" \
-"-t: timeout before connecting to SSH.\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" \
@@ -49,16 +51,21 @@ const char* USAGE_STRING =
 "-i: Run as a inetd service.\n" \
 "";
 
+/* Constants for options that have no one-character shorthand */
+#define OPT_ONTIMEOUT   257
+
 static struct option const_options[] = {
     { "inetd",      no_argument,            &inetd,         1 },
     { "foreground", no_argument,            &foreground,    1 },
     { "background", no_argument,            &background,    1 },
+    { "transparent", no_argument,           &transparent,   1 },
     { "numeric",    no_argument,            &numeric,       1 },
     { "verbose",    no_argument,            &verbose,       1 },
     { "user",       required_argument,      0,              'u' },
     { "config",     required_argument,      0,              'F' },
     { "pidfile",    required_argument,      0,              'P' },
     { "timeout",    required_argument,      0,              't' },
+    { "on-timeout", required_argument,      0,              OPT_ONTIMEOUT },
     { "listen",     required_argument,      0,              'p' },
     {}
 };
@@ -71,14 +78,36 @@ static const char *optstr = "vt:T:p:VP:F:";
 static void print_usage(void)
 {
     struct proto *p;
+    int i;
+    int res;
     char *prots = "";
 
-    for (p = get_first_protocol(); p; p = p->next)
-        asprintf(&prots, "%s\t[--%s <addr>]\n", prots, p->description);
+    p = get_builtins();
+    for (i = 0; i < get_num_builtins(); i++) {
+        res = asprintf(&prots, "%s\t[--%s <addr>]\n", prots, p[i].description);
+        CHECK_RES_DIE(res, "asprintf");
+    }
 
     fprintf(stderr, USAGE_STRING, prots);
 }
 
+static void printcaps(void) {
+#ifdef LIBCAP
+    cap_t caps;
+    char* desc;
+    ssize_t len;
+
+    caps = cap_get_proc();
+
+    desc = cap_to_text(caps, &len);
+
+    fprintf(stderr, "capabilities: %s\n", desc);
+
+    cap_free(caps);
+    cap_free(desc);
+#endif
+}
+
 static void printsettings(void)
 {
     char buf[NI_MAXHOST];
@@ -98,7 +127,8 @@ static void printsettings(void)
     for (a = addr_listen; a; a = a->ai_next) {
         fprintf(stderr, "\t%s\n", sprintaddr(buf, sizeof(buf), a));
     }
-    fprintf(stderr, "timeout to ssh: %d\n", probing_timeout);
+    fprintf(stderr, "timeout: %d\non-timeout: %s\n", probing_timeout,
+            timeout_protocol()->description);
 }
 
 
@@ -195,8 +225,8 @@ static int config_protocols(config_t *config, struct proto **prots)
 
             prot = config_setting_get_elem(setting, i);
             if ((config_setting_lookup_string(prot, "name", &name) &&
-                  config_setting_lookup_string(prot, "host", &hostname) &&
-                  config_setting_lookup_string(prot, "port", &port)
+                 config_setting_lookup_string(prot, "host", &hostname) &&
+                 config_setting_lookup_string(prot, "port", &port)
                 )) {
                 p->description = name;
                 config_setting_lookup_string(prot, "service", &(p->service));
@@ -205,24 +235,26 @@ static int config_protocols(config_t *config, struct proto **prots)
 
 
                 probes = config_setting_get_member(prot, "probe");
-                if (config_setting_is_array(probes)) {
-                    /* If 'probe' is an array, setup a regex probe using the
-                     * array of strings as pattern */
+                if (probes) {
+                    if (config_setting_is_array(probes)) {
+                        /* If 'probe' is an array, setup a regex probe using the
+                         * array of strings as pattern */
 
-                    setup_regex_probe(p, probes);
+                        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);
+                    } 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);
                         }
-                    } else {
-                        fprintf(stderr, "%s: illegal probe name\n", name);
-                        exit(1);
                     }
                 }
             }
@@ -242,7 +274,8 @@ static int config_protocols(config_t *config, struct proto **prots)
 static int config_parse(char *filename, struct addrinfo **listen, struct proto **prots)
 {
     config_t config;
-    long int timeout;
+    int timeout;
+    const char* str;
 
     config_init(&config);
     if (config_read_file(&config, filename) == CONFIG_FALSE) {
@@ -257,11 +290,16 @@ static int config_parse(char *filename, struct addrinfo **listen, struct proto *
     config_lookup_bool(&config, "inetd", &inetd);
     config_lookup_bool(&config, "foreground", &foreground);
     config_lookup_bool(&config, "numeric", &numeric);
+    config_lookup_bool(&config, "transparent", &transparent);
 
-    if (config_lookup_int(&config, "timeout", &timeout) == CONFIG_TRUE) {
+    if (config_lookup_int(&config, "timeout", (int *)&timeout) == CONFIG_TRUE) {
         probing_timeout = timeout;
     }
 
+    if (config_lookup_string(&config, "on-timeout", &str)) {
+        set_ontimeout(str);
+    }
+
     config_lookup_string(&config, "user", &user_name);
     config_lookup_string(&config, "pidfile", &pid_file);
 
@@ -388,6 +426,10 @@ next_arg:
              probing_timeout = atoi(optarg);
             break;
 
+        case OPT_ONTIMEOUT:
+            set_ontimeout(optarg);
+            break;
+
         case 'p':
             /* find the end of the listen list */
             for (a = &addr_listen; *a; a = &((*a)->ai_next));
@@ -425,7 +467,7 @@ next_arg:
 
     set_protocol_list(prots);
 
-    if (!addr_listen) {
+    if (!addr_listen && !inetd) {
         fprintf(stderr, "No listening address specified; use at least one -p option\n");
         exit(1);
     }
@@ -483,9 +525,13 @@ int main(int argc, char *argv[])
    if (user_name)
        drop_privileges(user_name);
 
+
    /* Open syslog connection */
    setup_syslog(argv[0]);
 
+   if (verbose)
+       printcaps();
+
    main_loop(listen_sockets, num_addr_listen);
 
    return 0;

sslh-select.c

@@ -64,14 +64,24 @@ int tidy_connection(struct connection *cnx, fd_set *fds, fd_set *fds2)
             close(cnx->q[i].fd);
             FD_CLR(cnx->q[i].fd, fds);
             FD_CLR(cnx->q[i].fd, fds2);
-            if (cnx->q[i].defered_data)
-                free(cnx->q[i].defered_data);
+            if (cnx->q[i].deferred_data)
+                free(cnx->q[i].deferred_data);
         }
     }
     init_cnx(cnx);
     return 0;
 }
 
+/* if fd becomes higher than FD_SETSIZE, things won't work so well with FD_SET
+ * and FD_CLR. Need to drop connections if we go above that limit */
+int fd_is_in_range(int fd) {
+    if (fd >= FD_SETSIZE) {
+        log_message(LOG_ERR, "too many open file descriptor to monitor them all -- dropping connection\n");
+        return 0;
+    }
+    return 1;
+}
+
 /* Accepts a connection from the main socket and assigns it to an empty slot.
  * If no slots are available, allocate another few. If that fails, drop the
  * connexion */
@@ -83,6 +93,9 @@ 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))
+        return -1;
+
     res = set_nonblock(in_socket);
     if (res == -1) return -1;
 
@@ -116,18 +129,16 @@ int accept_new_connection(int listen_socket, struct connection *cnx[], int* cnx_
 
 
 /* Connect queue 1 of connection to SSL; returns new file descriptor */
-int connect_queue(struct connection *cnx, struct addrinfo *addr, 
-                  const char* cnx_name,
-                  fd_set *fds_r, fd_set *fds_w)
+int connect_queue(struct connection *cnx, fd_set *fds_r, fd_set *fds_w)
 {
     struct queue *q = &cnx->q[1];
 
-    q->fd = connect_addr(addr, cnx_name);
-    if (q->fd != -1) {
+    q->fd = connect_addr(cnx, cnx->q[0].fd);
+    if ((q->fd != -1) && fd_is_in_range(q->fd)) {
         log_connection(cnx);
         set_nonblock(q->fd);
-        flush_defered(q);
-        if (q->defered_data) {
+        flush_deferred(q);
+        if (q->deferred_data) {
             FD_SET(q->fd, fds_w);
         } else {
             FD_SET(q->fd, fds_r);
@@ -177,13 +188,13 @@ int is_fd_active(int fd, fd_set* set)
 }
 
 /* Main loop: the idea is as follow:
- * - fds_r and fds_w contain the file descritors to monitor in read and write
+ * - fds_r and fds_w contain the file descriptors to monitor in read and write
  * - When a file descriptor goes off, process it: read from it, write the data
  * to its corresponding pair.
  * - When a file descriptor blocks when writing, remove the read fd from fds_r,
- * move the data to a defered buffer, and add the write fd to fds_w. Defered
+ * move the data to a deferred buffer, and add the write fd to fds_w. Defered
  * buffer is allocated dynamically.
- * - When we can write to a file descriptor that has defered data, we try to
+ * - When we can write to a file descriptor that has deferred data, we try to
  * write as much as we can. Once all data is written, remove the fd from fds_w
  * and add its corresponding pair to fds_r, free the buffer.
  *
@@ -197,7 +208,6 @@ void main_loop(int listen_sockets[], int num_addr_listen)
     struct timeval tv;
     int max_fd, in_socket, i, j, res;
     struct connection *cnx;
-    struct proto *prot;
     int num_cnx;  /* Number of connections in *cnx */
     int num_probing = 0; /* Number of connections currently probing 
                           * We use this to know if we need to time out of
@@ -255,18 +265,19 @@ void main_loop(int listen_sockets[], int num_addr_listen)
             if (cnx[i].q[0].fd != -1) {
                 for (j = 0; j < 2; j++) {
                     if (is_fd_active(cnx[i].q[j].fd, &writefds)) {
-                        res = flush_defered(&cnx[i].q[j]);
+                        res = flush_deferred(&cnx[i].q[j]);
                         if ((res == -1) && ((errno == EPIPE) || (errno == ECONNRESET))) {
                             if (cnx[i].state == ST_PROBING) num_probing--;
                             tidy_connection(&cnx[i], &fds_r, &fds_w);
                             if (verbose)
                                 fprintf(stderr, "closed slot %d\n", i);
-                        }
-                        /* If no defered data is left, stop monitoring the fd 
-                         * for write, and restart monitoring the other one for reads*/
-                        if (!cnx[i].q[j].defered_data_size) {
-                            FD_CLR(cnx[i].q[j].fd, &fds_w);
-                            FD_SET(cnx[i].q[1-j].fd, &fds_r);
+                        } else {
+                            /* If no deferred data is left, stop monitoring the fd 
+                             * for write, and restart monitoring the other one for reads*/
+                            if (!cnx[i].q[j].deferred_data_size) {
+                                FD_CLR(cnx[i].q[j].fd, &fds_w);
+                                FD_SET(cnx[i].q[1-j].fd, &fds_r);
+                            }
                         }
                     }
                 }
@@ -289,27 +300,27 @@ void main_loop(int listen_sockets[], int num_addr_listen)
                             dump_connection(&cnx[i]);
                             exit(1);
                         }
-                        num_probing--;
-                        cnx[i].state = ST_SHOVELING;
 
                         /* If timed out it's SSH, otherwise the client sent
                          * data so probe the protocol */
                         if ((cnx[i].probe_timeout < time(NULL))) {
-                            prot = timeout_protocol();
+                            cnx[i].proto = timeout_protocol();
                         } else {
-                            prot = probe_client_protocol(&cnx[i]);
+                            res = probe_client_protocol(&cnx[i]);
+                            if (res == PROBE_AGAIN)
+                                continue;
                         }
 
+                        num_probing--;
+                        cnx[i].state = ST_SHOVELING;
+
                         /* libwrap check if required for this protocol */
-                        if (prot->service && 
-                            check_access_rights(in_socket, prot->service)) {
+                        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], 
-                                                prot->saddr, 
-                                                prot->description, 
-                                                &fds_r, &fds_w);
+                            res = connect_queue(&cnx[i], &fds_r, &fds_w);
                         }
 
                         if (res >= max_fd)

sslh.pod

@@ -2,59 +2,40 @@
 
 =head1 NAME
 
- sslh - ssl/ssh multiplexer
+ sslh - protocol demultiplexer
 
 =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<-u> I<username>] [B<-P> I<pidfile>] [-v] [-i] [-V] [-f] [-n]
+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]
 
 =head1 DESCRIPTION
 
-B<sslh> accepts connections in HTTP, HTTPS, SSH, OpenVPN,
-tinc, XMPP, or any other protocol that can be tested using a
-regular expression, on the same port. This makes it possible
-to connect to any of these servers on port 443 (e.g. from
-inside a corporate firewall, which almost never block port
-443) while still serving HTTPS on that port. 
+B<sslh> accepts connections on specified ports, and forwards
+them further based on tests performed on the first data
+packet sent by the remote client.
 
+Probes for HTTP, SSL, SSH, OpenVPN, tinc, XMPP are
+implemented, and any other protocol that can be tested using
+a regular expression, can be recognised. A typical use case
+is to allow serving several services on port 443 (e.g. to
+connect to ssh from inside a corporate firewall, which
+almost never block port 443) while still serving HTTPS on
+that port. 
 
-The idea is to have B<sslh> listen to the external 443 port,
-accept the incoming connections, work out what type of
-connection it is, and then fordward to the appropriate
-server.
-
-=head2 Protocol detection
-
-The protocol detection is made based on the first bytes sent
-by the client: SSH connections start by identifying each
-other's versions using clear text "SSH-2.0" strings (or
-equivalent version strings). This is defined in RFC4253,
-4.2. Meanwhile, OpenVPN clients start with 0x00 0x0D 0x38,
-tinc clients start with "0 ", and XMPP client start with a
-packet containing "jabber".
-
-Additionally, two kind of SSH clients exist: the client
-waits for the server to send its version string ("Shy"
-client, which is the case of OpenSSH and Putty), or the
-client sends its version first ("Bold" client, which is the
-case of Bitvise Tunnelier and ConnectBot). 
-
-If the client stays quiet after the timeout period, B<sslh>
-will connect to the first protocol defined (in the
-configuration file, or on the command line), so SSH should
-be defined first in B<sslh> configuration to accomodate for
-shy SSH clients.
+Hence B<sslh> acts as a protocol demultiplexer, or a
+switchboard. Its name comes from its original function to
+serve SSH and HTTPS on the same port.
 
 =head2 Libwrap support
 
-One drawback of B<sslh> is that the B<ssh> and B<httpd>
-servers do not see the original IP address of the client
-anymore, as the connection is forwarded through B<sslh>.
-B<sslh> provides enough logging to circumvent that problem.
-However it is common to limit access to B<ssh> using
-B<libwrap> or B<tcpd>. For this reason, B<sslh> can be
-compiled to check SSH accesses against SSH access lists as
-defined in F</etc/hosts.allow> and F</etc/hosts.deny>.
+One drawback of B<sslh> is that the servers do not see the
+original IP address of the client anymore, as the connection
+is forwarded through B<sslh>.
+
+For this reason, B<sslh> can be compiled with B<libwrap> to
+check accesses defined in F</etc/hosts.allow> and
+F</etc/hosts.deny>.  Libwrap services can be defined using
+the configuration file.
 
 =head2 Configuration file
 
@@ -78,6 +59,18 @@ 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
+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
+protocols will never be tried.
+
+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.
 
 =head1 OPTIONS
 
@@ -85,9 +78,13 @@ than regular expressions.
 
 =item B<-t> I<num>, B<--timeout> I<num>
 
-Timeout before forwarding the connection to the first
-configured protocol (which should usually be SSH). Default
-is 2s.
+Timeout before forwarding the connection to the timeout
+protocol (which should usually be SSH). Default is 2s.
+
+=item B<--on-timeout> I<protocol name>
+
+Name of the protocol to connect to after the timeout period
+is over. Default is 'ssh'.
 
 =item B<-p> I<listening address>, B<--listen> I<listening address>
 
@@ -100,6 +97,8 @@ several addresses.
 
 =item B<--ssl> I<target address>
 
+=item B<--tls> I<target address>
+
 Interface and port on which to forward SSL connection,
 typically I<localhost:443>.
 
@@ -107,6 +106,11 @@ Note that you can set B<sslh> to listen on I<ext_ip:443> and
 B<httpd> to listen on I<localhost:443>: this allows clients
 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
+you wish to accept SSLv2, use B<--default> instead.
+
 =item B<--ssh> I<target address>
 
 Interface and port on which to forward SSH connections,
@@ -122,6 +126,11 @@ typically I<localhost:1194>.
 Interface and port on which to forward XMPP connections,
 typically I<localhost:5222>.
 
+=item B<--http> I<target address>
+
+Interface and port on which to forward HTTP connections,
+typically I<localhost:80>.
+
 =item B<--tinc> I<target address>
 
 Interface and port on which to forward tinc connections,
@@ -130,6 +139,14 @@ typically I<localhost:655>.
 This is experimental. If you use this feature, please report
 the results (even if it works!)
 
+=item B<--anyprot> I<target address>
+
+Interface and port on which to forward if no other protocol
+has been found. Because B<sslh> tries protocols in the order
+specified on the command line, this should be specified
+last. If no default is specified, B<sslh> will forward
+unknown protocols to the first protocol specified.
+
 =item B<-v>, B<--verbose>
 
 Increase verboseness.

t

@@ -18,10 +18,11 @@ my $pidfile = "/tmp/sslh_test.pid";
 my $SSL_CNX =           1;
 my $SSH_SHY_CNX =       1;
 my $SSH_BOLD_CNX =      1;
+my $SSH_PROBE_AGAIN =   1;
 my $SSL_MIX_SSH =       1;
 my $SSH_MIX_SSL =       1;
-my $BIG_MSG =           1;
-my $STALL_CNX =         1;
+my $BIG_MSG =           0; # This test is unreliable
+my $STALL_CNX =         0; # This test needs fixing
 
 # Robustness tests. These are mostly to achieve full test
 # coverage, but do not necessarily result in an actual test
@@ -57,15 +58,17 @@ for my $binary (@binaries) {
         my $user = (getpwuid $<)[0]; # Run under current username
         my $cmd = "./$binary -v -f -u $user --listen localhost:$sslh_port --ssh $ssh_address --ssl $ssl_address -P $pidfile";
         warn "$cmd\n";
-        exec $cmd;
-        #exec "valgrind --leak-check=full ./sslh-select -v -f -u $user --listen localhost:$sslh_port --ssh $ssh_address -ssl $ssl_address -P $pidfile";
+        #exec $cmd;
+        exec "valgrind --leak-check=full ./$binary -v -f -u $user --listen localhost:$sslh_port --ssh $ssh_address -ssl $ssl_address -P $pidfile";
         exit 0;
     }
     warn "spawned $sslh_pid\n";
-    sleep 1;  # valgrind can be heavy -- wait 5 seconds
+    sleep 5;  # valgrind can be heavy -- wait 5 seconds
 
 
     my $test_data = "hello world\n";
+#    my $ssl_test_data = (pack 'n', ((length $test_data) + 2)) .  $test_data;
+    my $ssl_test_data = "\x16\x03\x03$test_data\n";
 
 # Test: SSL connection
     if ($SSL_CNX) {
@@ -73,9 +76,10 @@ for my $binary (@binaries) {
         my $cnx_l = new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
         warn "$!\n" unless $cnx_l;
         if (defined $cnx_l) {
-            print $cnx_l $test_data;
-            my $data = <$cnx_l>;
-            is($data, "ssl: $test_data", "SSL connection");
+            print $cnx_l $ssl_test_data;
+            my $data;
+            my $n = sysread $cnx_l, $data, 1024;
+            is($data, "ssl: $ssl_test_data", "SSL connection");
         }
     }
 
@@ -105,13 +109,29 @@ for my $binary (@binaries) {
         }
     }
 
+# Test: PROBE_AGAIN, incomplete first frame
+    if ($SSH_PROBE_AGAIN) {
+        print "***Test: incomplete SSH first frame\n";
+        my $cnx_h = new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
+        warn "$!\n" unless $cnx_h;
+        if (defined $cnx_h) {
+            my $td = "SSH-2.0 testsuite\t$test_data";
+            print $cnx_h substr $td, 0, 2;
+            sleep 1;
+            print $cnx_h substr $td, 2;
+            my $data = <$cnx_h>;
+            is($data, "ssh: $td", "Incomplete first SSH frame");
+        }
+    }
+
+
 # Test: One SSL half-started then one SSH
     if ($SSL_MIX_SSH) {
         print "***Test: One SSL half-started then one SSH\n";
         my $cnx_l = new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
         warn "$!\n" unless $cnx_l;
         if (defined $cnx_l) {
-            print $cnx_l $test_data;
+            print $cnx_l $ssl_test_data;
             my $cnx_h= new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
             warn "$!\n" unless $cnx_h;
             if (defined $cnx_h) {
@@ -120,8 +140,9 @@ for my $binary (@binaries) {
                 my $data_h = <$cnx_h>;
                 is($data_h, "ssh: $test_data", "SSH during SSL being established");
             }
-            my $data = <$cnx_l>;
-            is($data, "ssl: $test_data", "SSL connection interrupted by SSH");
+            my $data;
+            my $n = sysread $cnx_l, $data, 1024;
+            is($data, "ssl: $ssl_test_data", "SSL connection interrupted by SSH");
         }
     }
 
@@ -135,9 +156,10 @@ for my $binary (@binaries) {
             my $cnx_l = new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
             warn "$!\n" unless $cnx_l;
             if (defined $cnx_l) {
-                print $cnx_l $test_data;
-                my $data = <$cnx_l>;
-                is($data, "ssl: $test_data", "SSL during SSH being established");
+                print $cnx_l $ssl_test_data;
+                my $data;
+                my $n = sysread $cnx_l, $data, 1024;
+                is($data, "ssl: $ssl_test_data", "SSL during SSH being established");
             }
             print $cnx_h $test_data;
             my $data = <$cnx_h>;
@@ -151,19 +173,24 @@ for my $binary (@binaries) {
         print "***Test: big message\n";
         my $cnx_l = new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
         warn "$!\n" unless $cnx_l;
-        my $test_data2 = "helloworld";
-        my $rept = 10000;
+        my $rept = 1000;
+        my $test_data2 = $ssl_test_data . ("helloworld"x$rept);
         if (defined $cnx_l) {
-            print $cnx_l ($test_data2 x $rept);
-            print $cnx_l "\n";
-            my $data = <$cnx_l>;
-            is($data, "ssl: ". ($test_data2 x $rept) . "\n", "Big message");
+            my $n = syswrite $cnx_l, $test_data2;
+            my ($data);
+            $n = sysread $cnx_l, $data, 1 << 20;
+            is($data, "ssl: ". $test_data2, "Big message");
         }
     }
 
 # Test: Stalled connection
 # Create two connections, stall one, check the other one
 # works, unstall first and check it works fine
+# This test needs fixing.
+# Now that echosrv no longer works on "lines" (finishing
+# with '\n'), it may cut blocks randomly with prefixes.
+# The whole thing needs to be re-thought as it'll only
+# work by chance.
     if ($STALL_CNX) {
         print "***Test: Stalled connection\n";
         my $cnx_1 = new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
@@ -171,20 +198,21 @@ for my $binary (@binaries) {
         my $cnx_2 = new IO::Socket::INET(PeerHost => "localhost:$sslh_port");
         warn "$!\n" unless defined $cnx_2;
         my $test_data2 = "helloworld";
-        my $rept = 10000;
+        sleep 4;
+        my $rept = 1000;
         if (defined $cnx_1 and defined $cnx_2) {
             print $cnx_1 ($test_data2 x $rept);
             print $cnx_1 "\n";
             print $cnx_2 ($test_data2 x $rept);
             print $cnx_2 "\n";
             my $data = <$cnx_2>;
-            is($data, "ssl: " . ($test_data2 x $rept) . "\n", "Stalled connection (1)");
+            is($data, "ssh: " . ($test_data2 x $rept) . "\n", "Stalled connection (1)");
             print $cnx_2 ($test_data2 x $rept);
             print $cnx_2 "\n";
             $data = <$cnx_2>;
-            is($data, "ssl: " . ($test_data2 x $rept) . "\n", "Stalled connection (2)");
+            is($data, "ssh: " . ($test_data2 x $rept) . "\n", "Stalled connection (2)");
             $data = <$cnx_1>;
-            is($data, "ssl: " . ($test_data2 x $rept) . "\n", "Stalled connection (3)");
+            is($data, "ssh: " . ($test_data2 x $rept) . "\n", "Stalled connection (3)");
 
         }
     }