#!/bin/sh
# Copyright (C) 2010, 2012 Internet Systems Consortium, Inc. ("ISC")
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
# PERFORMANCE OF THIS SOFTWARE.
#
# Generate a DNS RR from an x.509 certificate
# Currently only supports TLSA, but can be extended to support
# other DANE types such as SMIMEA in the future.
#
# Requires: openssl
USAGE="$BASENAME [options] <filename>
Options:
-f <input format>: PEM | DLR
-n <name>: record name (default: _443._tcp)
-o <origin>: zone origin (default: none; name will be relative)
-m <matching type>: NONE (0) | SHA256 (1) | SHA512 (2)
-r <RR type>: TLSA
-s <selector>: FULL (0) | PK (1)
-t <ttl>: TTL of the TLSA record (default: none)
-u <certificate usage>: CA (0) | SERVICE (1) | TA (2) | DOMAIN (3)"
NM="_443._tcp"
CU=2
SELECTOR=0
MTYPE=1
IN=
FORM=PEM
TTL=
RRTYPE=TLSA
BASENAME=`basename $0`;
while getopts "xn:o:u:s:t:m:i:f:r:" c; do
case $c in
x) set -x; DEBUG=-x;;
m) MTYPE="$OPTARG";;
n) NM="$OPTARG";;
o) ORIGIN="$OPTARG";;
r) RRTYPE="$OPTARG";;
s) SELECTOR="$OPTARG";;
t) TTL="$OPTARG";;
u) CU="$OPTARG";;
*) echo "$USAGE" 1>&2; exit 1;;
esac
done
shift `expr $OPTIND - 1 || true`
if test "$#" -eq 1; then
IN=$1
else
echo "$USAGE" 1>&2; exit 1
fi
ORIGIN=`echo $ORIGIN | sed 's/\([^.]$\)/\1./'`
if [ -n "$ORIGIN" ]; then
NM=`echo $NM | sed 's/\.$//'`
NM="$NM.$ORIGIN"
fi
case "$CU" in
[Cc][Aa]) CU=0;;
[Ss][Ee][Rr][Vv]*) CU=1;;
[Tt][Aa]) CU=2;;
[Dd][Oo][Mm]*) CU=3;;
[0123]) ;;
*) echo "bad certificate usage -u \"$CU\"" 1>&2; exit 1;;
esac
case "$SELECTOR" in
[Ff][Uu][Ll][Ll]) SELECTOR=0;;
[Pp][Kk]) SELECTOR=1;;
[01]) ;;
*) echo "bad selector -s \"$SELECTOR\"" 1>&2; exit 1;;
esac
case "$MTYPE" in
0|[Nn][Oo][Nn][Ee]) HASH='od -A n -v -t xC';;
1|[Ss][Hh][Aa]256) HASH='openssl dgst -sha256';;
2|[Ss][Hh][Aa]512) HASH='openssl dgst -sha512';;
*) echo "bad matching type -m \"$MTYPE\"" 1>&2; exit 1;;
esac
case "$FORM" in
[Pp][Ee][Mm]) FORM=PEM;;
[Dd][Ll][Rr]) FORM=DLR;;
*) echo "bad input file format -f \"$FORM\"" 1>&2; exit 1
esac
case "$RRTYPE" in
[Tt][Ll][Ss][Aa]) RRTYPE=TLSA;;
*) echo "invalid RR type" 1>&2; exit 1
esac
if test -z "$IN" -o ! -s "$IN"; then
echo "bad input file -i \"$IN\"" 1>&2; exit 1
fi
echo "; $BASENAME -o$NM -u$CU -s$SELECTOR -m$MTYPE -f$FORM $IN"
(if test "$SELECTOR" = 0; then
openssl x509 -in "$IN" -inform "$FORM" -outform DER
else
openssl x509 -in "$IN" -inform "$FORM" -noout -pubkey \
| sed -e '/PUBLIC KEY/d' \
| openssl base64 -d
fi) \
| $HASH \
| awk '
# format Association Data as in Appendix C of the DANE RFC
BEGIN {
print "'"$NM\t\t$TTL\tIN TLSA\t$CU $SELECTOR $MTYPE"' (";
leader = "\t\t\t\t\t";
}
/.+/ {
gsub(/ +/, "", $0);
buf = buf $0;
while (length(buf) >= 36) {
print leader substr(buf, 1, 36);
buf = substr(buf, 37);
}
}
END {
if (length(buf) > 34)
print leader buf "\n" leader ")";
else
print leader buf " )";
}'