125 lines
4.4 KiB
Bash
125 lines
4.4 KiB
Bash
# $OpenBSD: hostkey-rotate.sh,v 1.9 2020/10/07 06:38:16 djm Exp $
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# Placed in the Public Domain.
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tid="hostkey rotate"
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rm -f $OBJ/hkr.* $OBJ/ssh_proxy.orig $OBJ/ssh_proxy.orig
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grep -vi 'hostkey' $OBJ/sshd_proxy > $OBJ/sshd_proxy.orig
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mv $OBJ/ssh_proxy $OBJ/ssh_proxy.orig
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grep -vi 'globalknownhostsfile' $OBJ/ssh_proxy.orig > $OBJ/ssh_proxy
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echo "UpdateHostkeys=yes" >> $OBJ/ssh_proxy
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echo "GlobalKnownHostsFile=none" >> $OBJ/ssh_proxy
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rm $OBJ/known_hosts
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# The "primary" key type is ed25519 since it's supported even when built
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# without OpenSSL. The secondary is RSA if it's supported.
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primary="ssh-ed25519"
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secondary="$primary"
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trace "prepare hostkeys"
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nkeys=0
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all_algs=""
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for k in $SSH_HOSTKEY_TYPES; do
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${SSHKEYGEN} -qt $k -f $OBJ/hkr.$k -N '' || fatal "ssh-keygen $k"
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echo "Hostkey $OBJ/hkr.${k}" >> $OBJ/sshd_proxy.orig
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nkeys=`expr $nkeys + 1`
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test "x$all_algs" = "x" || all_algs="${all_algs},"
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all_algs="${all_algs}$k"
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case "$k" in
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ssh-rsa) secondary="ssh-rsa" ;;
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esac
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done
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dossh() {
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# All ssh should succeed in this test
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${SSH} -F $OBJ/ssh_proxy "$@" x true || fail "ssh $@ failed"
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}
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expect_nkeys() {
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_expected=$1
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_message=$2
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_n=`wc -l $OBJ/known_hosts | awk '{ print $1 }'` || fatal "wc failed"
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[ "x$_n" = "x$_expected" ] || fail "$_message (got $_n wanted $_expected)"
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}
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check_key_present() {
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_type=$1
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_kfile=$2
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test "x$_kfile" = "x" && _kfile="$OBJ/hkr.${_type}.pub"
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_kpub=`awk "/$_type /"' { print $2 }' < $_kfile` || \
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fatal "awk failed"
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fgrep "$_kpub" $OBJ/known_hosts > /dev/null
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}
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cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy
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# Connect to sshd with StrictHostkeyChecking=no
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verbose "learn hostkey with StrictHostKeyChecking=no"
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>$OBJ/known_hosts
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dossh -oHostKeyAlgorithms=$primary -oStrictHostKeyChecking=no
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# Verify no additional keys learned
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expect_nkeys 1 "unstrict connect keys"
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check_key_present $primary || fail "unstrict didn't learn key"
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# Connect to sshd as usual
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verbose "learn additional hostkeys"
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dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$all_algs
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# Check that other keys learned
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expect_nkeys $nkeys "learn hostkeys"
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for k in $SSH_HOSTKEY_TYPES; do
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check_key_present $k || fail "didn't learn keytype $k"
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done
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# Check each key type
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for k in $SSH_HOSTKEY_TYPES; do
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verbose "learn additional hostkeys, type=$k"
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dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$k,$all_algs
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expect_nkeys $nkeys "learn hostkeys $k"
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check_key_present $k || fail "didn't learn $k correctly"
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done
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# Change one hostkey (non primary) and relearn
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if [ "$primary" != "$secondary" ]; then
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verbose "learn changed non-primary hostkey type=${secondary}"
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mv $OBJ/hkr.${secondary}.pub $OBJ/hkr.${secondary}.pub.old
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rm -f $OBJ/hkr.${secondary}
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${SSHKEYGEN} -qt ${secondary} -f $OBJ/hkr.${secondary} -N '' || \
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fatal "ssh-keygen $secondary"
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dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$all_algs
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# Check that the key was replaced
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expect_nkeys $nkeys "learn hostkeys"
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check_key_present ${secondary} $OBJ/hkr.${secondary}.pub.old && \
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fail "old key present"
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check_key_present ${secondary} || fail "didn't learn changed key"
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fi
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# Add new hostkey (primary type) to sshd and connect
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verbose "learn new primary hostkey"
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${SSHKEYGEN} -qt ${primary} -f $OBJ/hkr.${primary}-new -N '' || fatal "ssh-keygen ed25519"
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( cat $OBJ/sshd_proxy.orig ; echo HostKey $OBJ/hkr.${primary}-new ) \
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> $OBJ/sshd_proxy
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# Check new hostkey added
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dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary},$all_algs
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expect_nkeys `expr $nkeys + 1` "learn hostkeys"
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check_key_present ${primary} || fail "current key missing"
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check_key_present ${primary} $OBJ/hkr.${primary}-new.pub || fail "new key missing"
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# Remove old hostkey (primary type) from sshd
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verbose "rotate primary hostkey"
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cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy
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mv $OBJ/hkr.${primary}.pub $OBJ/hkr.${primary}.pub.old
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mv $OBJ/hkr.${primary}-new.pub $OBJ/hkr.${primary}.pub
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mv $OBJ/hkr.${primary}-new $OBJ/hkr.${primary}
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# Check old hostkey removed
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dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary},$all_algs
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expect_nkeys $nkeys "learn hostkeys"
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check_key_present ${primary} $OBJ/hkr.${primary}.pub.old && fail "old key present"
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check_key_present ${primary} || fail "didn't learn changed key"
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# Connect again, forcing rotated key
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verbose "check rotate primary hostkey"
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dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary}
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expect_nkeys 1 "learn hostkeys"
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check_key_present ${primary} || fail "didn't learn changed key"
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