1# $OpenBSD: hostkey-rotate.sh,v 1.9 2020/10/07 06:38:16 djm Exp $ 2# Placed in the Public Domain. 3 4tid="hostkey rotate" 5 6# 7# GNU (f)grep <=2.18, as shipped by FreeBSD<=12 and NetBSD<=9 will occasionally 8# fail to find ssh host keys in the hostkey-rotate test. If we have those 9# versions, use awk instead. 10# See # https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=258616 11# 12case `grep --version 2>&1 | awk '/GNU grep/{print $4}'` in 132.19) fgrep=good ;; 141.*|2.?|2.?.?|2.1?) fgrep=bad ;; # stock GNU grep 152.5.1*) fgrep=bad ;; # FreeBSD and NetBSD 16*) fgrep=good ;; 17esac 18if test "x$fgrep" = "xbad"; then 19 fgrep() 20{ 21 awk 'BEGIN{e=1} {if (index($0,"'$1'")>0){e=0;print}} END{exit e}' $2 22} 23fi 24 25rm -f $OBJ/hkr.* $OBJ/ssh_proxy.orig $OBJ/ssh_proxy.orig 26 27grep -vi 'hostkey' $OBJ/sshd_proxy > $OBJ/sshd_proxy.orig 28mv $OBJ/ssh_proxy $OBJ/ssh_proxy.orig 29grep -vi 'globalknownhostsfile' $OBJ/ssh_proxy.orig > $OBJ/ssh_proxy 30echo "UpdateHostkeys=yes" >> $OBJ/ssh_proxy 31echo "GlobalKnownHostsFile=none" >> $OBJ/ssh_proxy 32rm $OBJ/known_hosts 33 34# The "primary" key type is ed25519 since it's supported even when built 35# without OpenSSL. The secondary is RSA if it's supported. 36primary="ssh-ed25519" 37secondary="$primary" 38 39trace "prepare hostkeys" 40nkeys=0 41all_algs="" 42for k in $SSH_HOSTKEY_TYPES; do 43 ${SSHKEYGEN} -qt $k -f $OBJ/hkr.$k -N '' || fatal "ssh-keygen $k" 44 echo "Hostkey $OBJ/hkr.${k}" >> $OBJ/sshd_proxy.orig 45 nkeys=`expr $nkeys + 1` 46 test "x$all_algs" = "x" || all_algs="${all_algs}," 47 all_algs="${all_algs}$k" 48 case "$k" in 49 ssh-rsa) secondary="ssh-rsa" ;; 50 esac 51done 52 53dossh() { 54 # All ssh should succeed in this test 55 ${SSH} -F $OBJ/ssh_proxy "$@" x true || fail "ssh $@ failed" 56} 57 58expect_nkeys() { 59 _expected=$1 60 _message=$2 61 _n=`wc -l $OBJ/known_hosts | awk '{ print $1 }'` || fatal "wc failed" 62 [ "x$_n" = "x$_expected" ] || fail "$_message (got $_n wanted $_expected)" 63} 64 65check_key_present() { 66 _type=$1 67 _kfile=$2 68 test "x$_kfile" = "x" && _kfile="$OBJ/hkr.${_type}.pub" 69 _kpub=`awk "/$_type /"' { print $2 }' < $_kfile` || \ 70 fatal "awk failed" 71 fgrep "$_kpub" $OBJ/known_hosts > /dev/null 72} 73 74cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy 75 76# Connect to sshd with StrictHostkeyChecking=no 77verbose "learn hostkey with StrictHostKeyChecking=no" 78>$OBJ/known_hosts 79dossh -oHostKeyAlgorithms=$primary -oStrictHostKeyChecking=no 80# Verify no additional keys learned 81expect_nkeys 1 "unstrict connect keys" 82check_key_present $primary || fail "unstrict didn't learn key" 83 84# Connect to sshd as usual 85verbose "learn additional hostkeys" 86dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$all_algs 87# Check that other keys learned 88expect_nkeys $nkeys "learn hostkeys" 89for k in $SSH_HOSTKEY_TYPES; do 90 check_key_present $k || fail "didn't learn keytype $k" 91done 92 93# Check each key type 94for k in $SSH_HOSTKEY_TYPES; do 95 verbose "learn additional hostkeys, type=$k" 96 dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$k,$all_algs 97 expect_nkeys $nkeys "learn hostkeys $k" 98 check_key_present $k || fail "didn't learn $k correctly" 99done 100 101# Change one hostkey (non primary) and relearn 102if [ "$primary" != "$secondary" ]; then 103 verbose "learn changed non-primary hostkey type=${secondary}" 104 mv $OBJ/hkr.${secondary}.pub $OBJ/hkr.${secondary}.pub.old 105 rm -f $OBJ/hkr.${secondary} 106 ${SSHKEYGEN} -qt ${secondary} -f $OBJ/hkr.${secondary} -N '' || \ 107 fatal "ssh-keygen $secondary" 108 dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$all_algs 109 # Check that the key was replaced 110 expect_nkeys $nkeys "learn hostkeys" 111 check_key_present ${secondary} $OBJ/hkr.${secondary}.pub.old && \ 112 fail "old key present" 113 check_key_present ${secondary} || fail "didn't learn changed key" 114fi 115 116# Add new hostkey (primary type) to sshd and connect 117verbose "learn new primary hostkey" 118${SSHKEYGEN} -qt ${primary} -f $OBJ/hkr.${primary}-new -N '' || fatal "ssh-keygen ed25519" 119( cat $OBJ/sshd_proxy.orig ; echo HostKey $OBJ/hkr.${primary}-new ) \ 120 > $OBJ/sshd_proxy 121# Check new hostkey added 122dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary},$all_algs 123expect_nkeys `expr $nkeys + 1` "learn hostkeys" 124check_key_present ${primary} || fail "current key missing" 125check_key_present ${primary} $OBJ/hkr.${primary}-new.pub || fail "new key missing" 126 127# Remove old hostkey (primary type) from sshd 128verbose "rotate primary hostkey" 129cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy 130mv $OBJ/hkr.${primary}.pub $OBJ/hkr.${primary}.pub.old 131mv $OBJ/hkr.${primary}-new.pub $OBJ/hkr.${primary}.pub 132mv $OBJ/hkr.${primary}-new $OBJ/hkr.${primary} 133# Check old hostkey removed 134dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary},$all_algs 135expect_nkeys $nkeys "learn hostkeys" 136check_key_present ${primary} $OBJ/hkr.${primary}.pub.old && fail "old key present" 137check_key_present ${primary} || fail "didn't learn changed key" 138 139# Connect again, forcing rotated key 140verbose "check rotate primary hostkey" 141dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary} 142expect_nkeys 1 "learn hostkeys" 143check_key_present ${primary} || fail "didn't learn changed key" 144