https traffic logger

I’m currently writing a Simulator (really a mock) for some server, and more precisely for the SOAP interface it provides. All traffic is done only in https, and for debug purpose I needed to dump traces of the communication between a client and the real WebService, to compare them with the communication I have between the same client and the fake WebService. So here is a tiny script that acts as a proxy to unwrap/log/re-wrap SSL stuff.

	#!/bin/bash

	# this allows to dump clear-text form of the exchanges between SSL client and SSL server
	# client-side verification has to be disabled of course
	# anyway, useful for debugging

	# to run this you'll need
	# - a unix system
	# - socat
	# - ncat (part of nmap 5.0 suite)

	# Example of use:
	# $ ssl_tee 10.23.166.132:443 cat > logs.raw
	# ... connect your client to localhost:10443
	# ^C

	# Then you can inspect the trace of the https exchanges in the logs

	REMOTE=$1
	FILTER=$2
	LOCALPORT=10443
	PRINTER=""

	tempdir=$(mktemp -d) \|\| exit

	backpipe="$tempdir/backpipe"
	prettypipe="$tempdir/prettypipe"
	mkfifo "$backpipe" "$prettypipe" \|\| exit

	function cleanUp() {
	rm -rf -- "$tempdir"
	if [ -n "$PRINTER" ]; then
	wait $PRINTER
	fi
	}

	trap "cleanUp" EXIT

	# apply a filter to the filesystem output
	cat < $prettypipe \| $FILTER &
	PRINTER=$!

	# main loop: listen on $LOCALPORT, and redirect to $IP:443
	# can this be done with ncat only ?
	socat -T0 OPENSSL:$REMOTE,verify=0 STDIO 0<$backpipe \| \
	tee -a $prettypipe \| \
	ncat --listen --ssl --keep-open localhost $LOCALPORT \| \
	tee -a $prettypipe 1>$backpipe

	# Just in case the main loop ends for whatever reason.
	# In general, this script should be interrupted by ^C
	cleanUp
	trap - EXIT
	exit

view raw ssl_tee.sh hosted with ❤ by GitHub

I have the feeling all this should be doable by using ncat only, but did not find how yet.