1# $OpenBSD: hostkey-rotate.sh,v 1.10 2022/01/05 08:25:05 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="${all_algs}," 47 case "$k" in 48 ssh-rsa) 49 secondary="ssh-rsa" 50 all_algs="${all_algs}rsa-sha2-256,rsa-sha2-512,$k" 51 ;; 52 *) 53 all_algs="${all_algs}$k" 54 ;; 55 esac 56done 57 58dossh() { 59 # All ssh should succeed in this test 60 ${SSH} -F $OBJ/ssh_proxy "$@" x true || fail "ssh $@ failed" 61} 62 63expect_nkeys() { 64 _expected=$1 65 _message=$2 66 _n=`wc -l $OBJ/known_hosts | awk '{ print $1 }'` || fatal "wc failed" 67 [ "x$_n" = "x$_expected" ] || fail "$_message (got $_n wanted $_expected)" 68} 69 70check_key_present() { 71 _type=$1 72 _kfile=$2 73 test "x$_kfile" = "x" && _kfile="$OBJ/hkr.${_type}.pub" 74 _kpub=`awk "/$_type /"' { print $2 }' < $_kfile` || \ 75 fatal "awk failed" 76 fgrep "$_kpub" $OBJ/known_hosts > /dev/null 77} 78 79cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy 80 81# Connect to sshd with StrictHostkeyChecking=no 82verbose "learn hostkey with StrictHostKeyChecking=no" 83>$OBJ/known_hosts 84dossh -oHostKeyAlgorithms=$primary -oStrictHostKeyChecking=no 85# Verify no additional keys learned 86expect_nkeys 1 "unstrict connect keys" 87check_key_present $primary || fail "unstrict didn't learn key" 88 89# Connect to sshd as usual 90verbose "learn additional hostkeys" 91dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$all_algs 92# Check that other keys learned 93expect_nkeys $nkeys "learn hostkeys" 94for k in $SSH_HOSTKEY_TYPES; do 95 check_key_present $k || fail "didn't learn keytype $k" 96done 97 98# Check each key type 99for k in $SSH_HOSTKEY_TYPES; do 100 case "$k" in 101 ssh-rsa) alg="rsa-sha2-256,rsa-sha2-512,ssh-rsa" ;; 102 *) alg="$k" ;; 103 esac 104 verbose "learn additional hostkeys, type=$k" 105 dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$alg,$all_algs 106 expect_nkeys $nkeys "learn hostkeys $k" 107 check_key_present $k || fail "didn't learn $k correctly" 108done 109 110# Change one hostkey (non primary) and relearn 111if [ "$primary" != "$secondary" ]; then 112 verbose "learn changed non-primary hostkey type=${secondary}" 113 mv $OBJ/hkr.${secondary}.pub $OBJ/hkr.${secondary}.pub.old 114 rm -f $OBJ/hkr.${secondary} 115 ${SSHKEYGEN} -qt ${secondary} -f $OBJ/hkr.${secondary} -N '' || \ 116 fatal "ssh-keygen $secondary" 117 dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=$all_algs 118 # Check that the key was replaced 119 expect_nkeys $nkeys "learn hostkeys" 120 check_key_present ${secondary} $OBJ/hkr.${secondary}.pub.old && \ 121 fail "old key present" 122 check_key_present ${secondary} || fail "didn't learn changed key" 123fi 124 125# Add new hostkey (primary type) to sshd and connect 126verbose "learn new primary hostkey" 127${SSHKEYGEN} -qt ${primary} -f $OBJ/hkr.${primary}-new -N '' || fatal "ssh-keygen ed25519" 128( cat $OBJ/sshd_proxy.orig ; echo HostKey $OBJ/hkr.${primary}-new ) \ 129 > $OBJ/sshd_proxy 130# Check new hostkey added 131dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary},$all_algs 132expect_nkeys `expr $nkeys + 1` "learn hostkeys" 133check_key_present ${primary} || fail "current key missing" 134check_key_present ${primary} $OBJ/hkr.${primary}-new.pub || fail "new key missing" 135 136# Remove old hostkey (primary type) from sshd 137verbose "rotate primary hostkey" 138cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy 139mv $OBJ/hkr.${primary}.pub $OBJ/hkr.${primary}.pub.old 140mv $OBJ/hkr.${primary}-new.pub $OBJ/hkr.${primary}.pub 141mv $OBJ/hkr.${primary}-new $OBJ/hkr.${primary} 142# Check old hostkey removed 143dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary},$all_algs 144expect_nkeys $nkeys "learn hostkeys" 145check_key_present ${primary} $OBJ/hkr.${primary}.pub.old && fail "old key present" 146check_key_present ${primary} || fail "didn't learn changed key" 147 148# Connect again, forcing rotated key 149verbose "check rotate primary hostkey" 150dossh -oStrictHostKeyChecking=yes -oHostKeyAlgorithms=${primary} 151expect_nkeys 1 "learn hostkeys" 152check_key_present ${primary} || fail "didn't learn changed key" 153