#!/bin/bash

# This is a post-install script for monkeysphere, to transition an old
# (<0.23) setup to the new (>=0.23) setup.

# You should be able to run this script after any version >= 0.23 is
# installed.  This script should be well-behaved, even if it is run
# repeatedly.

# Written by
# Jameson Rollins <jrollins@finestructure.net>
# Daniel Kahn Gillmor <dkg@fifthhorseman.net>
#
# Copyright 2009, released under the GPL, version 3 or later

# NOTE: the reverse operation (downgrading) is not directly supported,
# and MAY LOCK YOU OUT OF YOUR SYSTEM, depending on how you have
# configured the monkeysphere!

# any unexpected errors should cause this script to bail:
set -e

SYSDATADIR=${MONKEYSPHERE_SYSDATADIR:-"/var/lib/monkeysphere"}

MADATADIR="${SYSDATADIR}/authentication"
MHDATADIR="${SYSDATADIR}/host"

STASHDIR="${SYSDATADIR}/backup-from-0.23-transition"


log() {
    printf "$@" >&2
}

# FIXME: implement this function better.  here, we only care about
# dots, *and* about reversing the regexification of them.
gpg_unescape_and_unregex() {
    sed  's/\\x5c\././g'
}


is_domain_name() {
    printf "%s" "$1" | egrep -q '^[[:alnum:]][[:alnum:]-.]*[[:alnum:]]$'
}

# run the authentication setup (this is also the first chance to bail
# if 0.23 is not fully-installed, because m-a did not exist before
# 0.23)
monkeysphere-authentication setup

# before 0.23, the old gnupg-host data directory used to contain the
# trust core and the system's ssh host key.  

if [ -d "$SYSDATADIR"/gnupg-host ] ; then

### transfer identity certifiers, if they don't already exist in the
### current setup:

    if monkeysphere-authentication list-identity-certifiers | \
	grep -q '^[A-F0-9]{40}:$' ; then
	log 'There are already certifiers in the new system!\nNot transferring any certifiers.\n'
    else
	# get the old host keygrip (don't know why there would be more
	# than one, but we'll transfer all tsigs made by any key that
	# had been given ultimate ownertrust):
	for authgrip in $(GNUPGHOME="$SYSDATADIR"/gnupg-host gpg --export-ownertrust | \
	    grep ':6:$'
	    sed -r 's/^[A-F0-9]{24}([A-F0-9]{16}):6:$/\1/') ; do
	    
	# we're assuming that old id certifiers were only added by old
	# versions of m-s c+, which added certifiers by ltsigning
	# entire keys.
	    
	# so we'll walk the list of tsigs from the old host key, and
	# add those keys as certifiers to the new system.

	    # FIXME: if an admin has run "m-s add-id-certifier $foo"
	    # multiple times for the same $foo, we'll only transfer
	    # one of those certifications (even if later
	    # certifications had different parameters).
	    
	    GNUPGHOME="$SYSDATADIR"/gnupg-host gpg --fingerprint --with-colons --fixed-list-mode --check-sigs | \
		cut -f 1,2,5,8,9,10 -d: | \
		egrep '^(fpr:::::|sig:!:'"$authgrip"':[[:digit:]]+ [[:digit:]]+:)' | \
		while IFS=: read -r type validity grip trustparams trustdomain fpr ; do
		case $type in
		    'fpr') # this is a new key
			keyfpr=$fpr
			;;
		    'sig') # deal with all trust signatures, including
			   # regexes if present.
			if [ "$keyfpr" ] ; then
			    trustdepth=${trustparams%% *}
			    trustlevel=${trustparams##* }
			    if [ "$trustlevel" -ge 120 ] ; then
				truststring=full
			    elif [ "$trustlevel" -ge 60 ] ; then
				truststring=marginal
			    else
				# trust levels below marginal are ignored.
				continue
			    fi

			    finaldomain=
			    if [ "$trustdomain" ] ; then
			    # FIXME: deal with translating
			    # $trustdomain back to a domain.
				if [ printf "%s" "$trustdomain" | egrep -q '^<\[\^>\]\+\[@\.\][^>]+>\$$' ] ; then
				    dpart=$(printf "%s" "$trustdomain" | sed -r 's/^<\[\^>\]\+\[@\.\]([^>]+)>\$$/\1/' | gpg_unescape_and_unregex)
				    if [ is_domain_name "$dpart" ]; then
					finaldomain="--domain $dpart"
				    else
					log "Does not seem to be a domain name (%s), not adding certifier\n" "$dpart"
					continue
				    fi
				else
				    log "Does not seem to be a standard gpg domain-based tsig (%s), not adding certifier\n" "$trustdomain"
				    continue
				fi
			    fi

			    CERTKEY=$(mktemp ${TMPDIR:-/tmp}/mstransition.XXXXXXXX)
			    log "Adding identity certifier with fingerprint %s\n" "$keyfpr"
			    GNUPGHOME="$SYSDATADIR"/gnupg-host gpg --export "0x$keyfpr" --export-clean >"$CERTKEY"
			    MONKEYSPHERE_PROMPT=false monkeysphere-authentication add-identity-certifier $finaldomain --trust "$truststring" --depth "$trustdepth" "$CERTKEY"
			    rm -f "$CERTKEY"
			    # clear the fingerprint so that we don't
			    # make additional tsigs on it if more uids
			    # are present:
			    $keyfpr=
			fi
			;;
		esac
	    done
	done
    fi

### transfer host key information (if present) into the new spot
    
    if [ -d "${MHDATADIR}" ] ; then
	log "Not transferring host key info because host directory already exists.\n"
    else
	if [ -s "$SYSDATADIR"/ssh_host_rsa_key ] || \
	    GNUPGHOME="$SYSDATADIR"/gnupg-host gpg --with-colons --list-secret-keys | grep -q '^sec:' ; then
	    
	# create host home
	    mkdir -p "${MHDATADIR}"
	    chmod 0700 "${MHDATADIR}"
	    
	    log "importing host key from old monkeysphere installation\n"
	    GNUPGHOME="$SYSDATADIR"/gnupg-host gpg --export-secret-keys \
		GNUPGHOME="$MHDATADIR" gpg --import
	    
	    monkeysphere-host update-gpg-pub-file
	else
	    log "No host key found in old monkeysphere install; not importing any host key.\n"
	fi
    fi


### get rid of this old stuff, since we've transferred it all:

    mkdir -p "$STASHDIR"
    chmod 0700 "$STASHDIR"
    mv "${SYSDATADIR}/gnupg-host" "$STASHDIR"
fi


# There is nothing in the old authentication directory that we should
# need to keep around, but it is not unreasonable to transfer keys to
# the new authentication keyring.
if [ -d "${SYSDATADIR}/gnupg-authentication" ] ; then

    GNUPGHOME="${SYSDATADIR}/gnupg-authentication" gpg --export | \
	monkeysphere-authentication gpg-cmd --import

    mkdir -p "$STASHDIR"
    chmod 0700 "$STASHDIR"
    mv "${SYSDATADIR}/gnupg-authentication" "$STASHDIR"
fi