1# $OpenBSD: hostkey-rotate.sh,v 1.5 2015/09/04 04:23:10 djm Exp $ 2# Placed in the Public Domain. 3 4tid="hostkey rotate" 5 6# Need full names here since they are used in HostKeyAlgorithms 7HOSTKEY_TYPES="ecdsa-sha2-nistp256 ssh-ed25519 ssh-rsa ssh-dss" 8 9rm -f $OBJ/hkr.* $OBJ/ssh_proxy.orig 10 11grep -vi 'hostkey' $OBJ/sshd_proxy > $OBJ/sshd_proxy.orig 12echo "UpdateHostkeys=yes" >> $OBJ/ssh_proxy 13rm $OBJ/known_hosts 14 15trace "prepare hostkeys" 16nkeys=0 17all_algs="" 18for k in `${SSH} -Q key-plain` ; do 19 ${SSHKEYGEN} -qt $k -f $OBJ/hkr.$k -N '' || fatal "ssh-keygen $k" 20 echo "Hostkey $OBJ/hkr.${k}" >> $OBJ/sshd_proxy.orig 21 nkeys=`expr $nkeys + 1` 22 test "x$all_algs" = "x" || all_algs="${all_algs}," 23 all_algs="${all_algs}$k" 24done 25 26dossh() { 27 # All ssh should succeed in this test 28 ${SSH} -F $OBJ/ssh_proxy "$@" x true || fail "ssh $@ failed" 29} 30 31expect_nkeys() { 32 _expected=$1 33 _message=$2 34 _n=`wc -l $OBJ/known_hosts | awk '{ print $1 }'` || fatal "wc failed" 35 [ "x$_n" = "x$_expected" ] || fail "$_message (got $_n wanted $_expected)" 36} 37 38check_key_present() { 39 _type=$1 40 _kfile=$2 41 test "x$_kfile" = "x" && _kfile="$OBJ/hkr.${_type}.pub" 42 _kpub=`awk "/$_type /"' { print $2 }' < $_kfile` || \ 43 fatal "awk failed" 44 fgrep "$_kpub" $OBJ/known_hosts > /dev/null 45} 46 47cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy 48 49# Connect to sshd with StrictHostkeyChecking=no 50verbose "learn hostkey with StrictHostKeyChecking=no" 51>$OBJ/known_hosts 52dossh -oHostKeyAlgorithms=ssh-ed25519 -oStrictHostKeyChecking=no 53# Verify no additional keys learned 54expect_nkeys 1 "unstrict connect keys" 55check_key_present ssh-ed25519 || fail "unstrict didn't learn key" 56 57# Connect to sshd as usual 58verbose "learn additional hostkeys" 59dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$all_algs 60# Check that other keys learned 61expect_nkeys $nkeys "learn hostkeys" 62check_key_present ssh-rsa || fail "didn't learn keys" 63 64# Check each key type 65for k in `${SSH} -Q key-plain` ; do 66 verbose "learn additional hostkeys, type=$k" 67 dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$k,$all_algs 68 expect_nkeys $nkeys "learn hostkeys $k" 69 check_key_present $k || fail "didn't learn $k" 70done 71 72# Change one hostkey (non primary) and relearn 73verbose "learn changed non-primary hostkey" 74mv $OBJ/hkr.ssh-rsa.pub $OBJ/hkr.ssh-rsa.pub.old 75rm -f $OBJ/hkr.ssh-rsa 76${SSHKEYGEN} -qt ssh-rsa -f $OBJ/hkr.ssh-rsa -N '' || fatal "ssh-keygen $k" 77dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$all_algs 78# Check that the key was replaced 79expect_nkeys $nkeys "learn hostkeys" 80check_key_present ssh-rsa $OBJ/hkr.ssh-rsa.pub.old && fail "old key present" 81check_key_present ssh-rsa || fail "didn't learn changed key" 82 83# Add new hostkey (primary type) to sshd and connect 84verbose "learn new primary hostkey" 85${SSHKEYGEN} -qt ssh-rsa -f $OBJ/hkr.ssh-rsa-new -N '' || fatal "ssh-keygen $k" 86( cat $OBJ/sshd_proxy.orig ; echo HostKey $OBJ/hkr.ssh-rsa-new ) \ 87 > $OBJ/sshd_proxy 88# Check new hostkey added 89dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=ssh-rsa,$all_algs 90expect_nkeys `expr $nkeys + 1` "learn hostkeys" 91check_key_present ssh-rsa || fail "current key missing" 92check_key_present ssh-rsa $OBJ/hkr.ssh-rsa-new.pub || fail "new key missing" 93 94# Remove old hostkey (primary type) from sshd 95verbose "rotate primary hostkey" 96cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy 97mv $OBJ/hkr.ssh-rsa.pub $OBJ/hkr.ssh-rsa.pub.old 98mv $OBJ/hkr.ssh-rsa-new.pub $OBJ/hkr.ssh-rsa.pub 99mv $OBJ/hkr.ssh-rsa-new $OBJ/hkr.ssh-rsa 100# Check old hostkey removed 101dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=ssh-rsa,$all_algs 102expect_nkeys $nkeys "learn hostkeys" 103check_key_present ssh-rsa $OBJ/hkr.ssh-rsa.pub.old && fail "old key present" 104check_key_present ssh-rsa || fail "didn't learn changed key" 105 106# Connect again, forcing rotated key 107verbose "check rotate primary hostkey" 108dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=ssh-rsa 109expect_nkeys 1 "learn hostkeys" 110check_key_present ssh-rsa || fail "didn't learn changed key" 111