# $OpenBSD: cert-userkey.sh,v 1.24 2019/12/11 18:47:14 djm Exp $ # Placed in the Public Domain. tid="certified user keys" rm -f $OBJ/authorized_keys_$USER $OBJ/user_ca_key* $OBJ/cert_user_key* cp $OBJ/sshd_proxy $OBJ/sshd_proxy_bak cp $OBJ/ssh_proxy $OBJ/ssh_proxy_bak PLAIN_TYPES=`$SSH -Q key-plain | maybe_filter_sk | sed 's/^ssh-dss/ssh-dsa/;s/^ssh-//'` EXTRA_TYPES="" rsa="" if echo "$PLAIN_TYPES" | grep '^rsa$' >/dev/null 2>&1 ; then rsa=rsa PLAIN_TYPES="$PLAIN_TYPES rsa-sha2-256 rsa-sha2-512" fi kname() { case $1 in rsa-sha2-*) n="$1" ;; sk-ecdsa-*) n="sk-ecdsa" ;; sk-ssh-ed25519*) n="sk-ssh-ed25519" ;; # subshell because some seds will add a newline *) n=$(echo $1 | sed 's/^dsa/ssh-dss/;s/^rsa/ssh-rsa/;s/^ed/ssh-ed/') ;; esac if [ -z "$rsa" ]; then echo "$n*,ssh-ed25519*" else echo "$n*,ssh-rsa*,ssh-ed25519*" fi } # Create a CA key if [ ! -z "$rsa" ]; then catype=rsa else catype=ed25519 fi ${SSHKEYGEN} -q -N '' -t $catype -f $OBJ/user_ca_key ||\ fail "ssh-keygen of user_ca_key failed" # Generate and sign user keys for ktype in $PLAIN_TYPES $EXTRA_TYPES ; do verbose "$tid: sign user ${ktype} cert" ${SSHKEYGEN} -q -N '' -t ${ktype} \ -f $OBJ/cert_user_key_${ktype} || \ fatal "ssh-keygen of cert_user_key_${ktype} failed" # Generate RSA/SHA2 certs for rsa-sha2* keys. case $ktype in rsa-sha2-*) tflag="-t $ktype" ;; *) tflag="" ;; esac ${SSHKEYGEN} -q -s $OBJ/user_ca_key -z $$ \ -I "regress user key for $USER" \ -n ${USER},mekmitasdigoat $tflag $OBJ/cert_user_key_${ktype} || \ fatal "couldn't sign cert_user_key_${ktype}" done # Test explicitly-specified principals for ktype in $EXTRA_TYPES $PLAIN_TYPES ; do t=$(kname $ktype) for privsep in yes ; do _prefix="${ktype} privsep $privsep" # Setup for AuthorizedPrincipalsFile rm -f $OBJ/authorized_keys_$USER ( cat $OBJ/sshd_proxy_bak echo "UsePrivilegeSeparation $privsep" echo "AuthorizedPrincipalsFile " \ "$OBJ/authorized_principals_%u" echo "TrustedUserCAKeys $OBJ/user_ca_key.pub" echo "PubkeyAcceptedKeyTypes ${t}" ) > $OBJ/sshd_proxy ( cat $OBJ/ssh_proxy_bak echo "PubkeyAcceptedKeyTypes ${t}" ) > $OBJ/ssh_proxy # Missing authorized_principals verbose "$tid: ${_prefix} missing authorized_principals" rm -f $OBJ/authorized_principals_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpectedly" fi # Empty authorized_principals verbose "$tid: ${_prefix} empty authorized_principals" echo > $OBJ/authorized_principals_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpectedly" fi # Wrong authorized_principals verbose "$tid: ${_prefix} wrong authorized_principals" echo gregorsamsa > $OBJ/authorized_principals_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpectedly" fi # Correct authorized_principals verbose "$tid: ${_prefix} correct authorized_principals" echo mekmitasdigoat > $OBJ/authorized_principals_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -ne 0 ]; then fail "ssh cert connect failed" fi # authorized_principals with bad key option verbose "$tid: ${_prefix} authorized_principals bad key opt" echo 'blah mekmitasdigoat' > $OBJ/authorized_principals_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpectedly" fi # authorized_principals with command=false verbose "$tid: ${_prefix} authorized_principals command=false" echo 'command="false" mekmitasdigoat' > \ $OBJ/authorized_principals_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpectedly" fi # authorized_principals with command=true verbose "$tid: ${_prefix} authorized_principals command=true" echo 'command="true" mekmitasdigoat' > \ $OBJ/authorized_principals_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost false >/dev/null 2>&1 if [ $? -ne 0 ]; then fail "ssh cert connect failed" fi # Setup for principals= key option rm -f $OBJ/authorized_principals_$USER ( cat $OBJ/sshd_proxy_bak echo "UsePrivilegeSeparation $privsep" echo "PubkeyAcceptedKeyTypes ${t}" ) > $OBJ/sshd_proxy ( cat $OBJ/ssh_proxy_bak echo "PubkeyAcceptedKeyTypes ${t}" ) > $OBJ/ssh_proxy # Wrong principals list verbose "$tid: ${_prefix} wrong principals key option" ( printf 'cert-authority,principals="gregorsamsa" ' cat $OBJ/user_ca_key.pub ) > $OBJ/authorized_keys_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpectedly" fi # Correct principals list verbose "$tid: ${_prefix} correct principals key option" ( printf 'cert-authority,principals="mekmitasdigoat" ' cat $OBJ/user_ca_key.pub ) > $OBJ/authorized_keys_$USER ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -ne 0 ]; then fail "ssh cert connect failed" fi done done basic_tests() { auth=$1 if test "x$auth" = "xauthorized_keys" ; then # Add CA to authorized_keys ( printf 'cert-authority ' cat $OBJ/user_ca_key.pub ) > $OBJ/authorized_keys_$USER else echo > $OBJ/authorized_keys_$USER extra_sshd="TrustedUserCAKeys $OBJ/user_ca_key.pub" fi for ktype in $PLAIN_TYPES ; do t=$(kname $ktype) for privsep in yes ; do _prefix="${ktype} privsep $privsep $auth" # Simple connect verbose "$tid: ${_prefix} connect" ( cat $OBJ/sshd_proxy_bak echo "UsePrivilegeSeparation $privsep" echo "PubkeyAcceptedKeyTypes ${t}" echo "$extra_sshd" ) > $OBJ/sshd_proxy ( cat $OBJ/ssh_proxy_bak echo "PubkeyAcceptedKeyTypes ${t}" ) > $OBJ/ssh_proxy ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true if [ $? -ne 0 ]; then fail "ssh cert connect failed" fi # Revoked keys verbose "$tid: ${_prefix} revoked key" ( cat $OBJ/sshd_proxy_bak echo "UsePrivilegeSeparation $privsep" echo "RevokedKeys $OBJ/cert_user_key_revoked" echo "PubkeyAcceptedKeyTypes ${t}" echo "$extra_sshd" ) > $OBJ/sshd_proxy cp $OBJ/cert_user_key_${ktype}.pub \ $OBJ/cert_user_key_revoked ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpecedly" fi verbose "$tid: ${_prefix} revoked via KRL" rm $OBJ/cert_user_key_revoked ${SSHKEYGEN} -kqf $OBJ/cert_user_key_revoked \ $OBJ/cert_user_key_${ktype}.pub ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpecedly" fi verbose "$tid: ${_prefix} empty KRL" ${SSHKEYGEN} -kqf $OBJ/cert_user_key_revoked ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -ne 0 ]; then fail "ssh cert connect failed" fi done # Revoked CA verbose "$tid: ${ktype} $auth revoked CA key" ( cat $OBJ/sshd_proxy_bak echo "RevokedKeys $OBJ/user_ca_key.pub" echo "PubkeyAcceptedKeyTypes ${t}" echo "$extra_sshd" ) > $OBJ/sshd_proxy ${SSH} -i $OBJ/cert_user_key_${ktype} -F $OBJ/ssh_proxy \ somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect succeeded unexpecedly" fi done verbose "$tid: $auth CA does not authenticate" ( cat $OBJ/sshd_proxy_bak echo "PubkeyAcceptedKeyTypes ${t}" echo "$extra_sshd" ) > $OBJ/sshd_proxy verbose "$tid: ensure CA key does not authenticate user" ${SSH} -i $OBJ/user_ca_key \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect with CA key succeeded unexpectedly" fi } basic_tests authorized_keys basic_tests TrustedUserCAKeys test_one() { ident=$1 result=$2 sign_opts=$3 auth_choice=$4 auth_opt=$5 if test "x$auth_choice" = "x" ; then auth_choice="authorized_keys TrustedUserCAKeys" fi for auth in $auth_choice ; do for ktype in $rsa ed25519 ; do cat $OBJ/sshd_proxy_bak > $OBJ/sshd_proxy if test "x$auth" = "xauthorized_keys" ; then # Add CA to authorized_keys ( printf "cert-authority${auth_opt} " cat $OBJ/user_ca_key.pub ) > $OBJ/authorized_keys_$USER else echo > $OBJ/authorized_keys_$USER echo "TrustedUserCAKeys $OBJ/user_ca_key.pub" \ >> $OBJ/sshd_proxy echo "PubkeyAcceptedKeyTypes ${t}*" \ >> $OBJ/sshd_proxy if test "x$auth_opt" != "x" ; then echo $auth_opt >> $OBJ/sshd_proxy fi fi verbose "$tid: $ident auth $auth expect $result $ktype" ${SSHKEYGEN} -q -s $OBJ/user_ca_key \ -I "regress user key for $USER" \ $sign_opts $OBJ/cert_user_key_${ktype} || fail "couldn't sign cert_user_key_${ktype}" ${SSH} -i $OBJ/cert_user_key_${ktype} \ -F $OBJ/ssh_proxy somehost true >/dev/null 2>&1 rc=$? if [ "x$result" = "xsuccess" ] ; then if [ $rc -ne 0 ]; then fail "$ident failed unexpectedly" fi else if [ $rc -eq 0 ]; then fail "$ident succeeded unexpectedly" fi fi done done } test_one "correct principal" success "-n ${USER}" test_one "host-certificate" failure "-n ${USER} -h" test_one "wrong principals" failure "-n foo" test_one "cert not yet valid" failure "-n ${USER} -V20200101:20300101" test_one "cert expired" failure "-n ${USER} -V19800101:19900101" test_one "cert valid interval" success "-n ${USER} -V-1w:+2w" test_one "wrong source-address" failure "-n ${USER} -Osource-address=10.0.0.0/8" test_one "force-command" failure "-n ${USER} -Oforce-command=false" # Behaviour is different here: TrustedUserCAKeys doesn't allow empty principals test_one "empty principals" success "" authorized_keys test_one "empty principals" failure "" TrustedUserCAKeys # Check explicitly-specified principals: an empty principals list in the cert # should always be refused. # AuthorizedPrincipalsFile rm -f $OBJ/authorized_keys_$USER echo mekmitasdigoat > $OBJ/authorized_principals_$USER test_one "AuthorizedPrincipalsFile principals" success "-n mekmitasdigoat" \ TrustedUserCAKeys "AuthorizedPrincipalsFile $OBJ/authorized_principals_%u" test_one "AuthorizedPrincipalsFile no principals" failure "" \ TrustedUserCAKeys "AuthorizedPrincipalsFile $OBJ/authorized_principals_%u" # principals= key option rm -f $OBJ/authorized_principals_$USER test_one "principals key option principals" success "-n mekmitasdigoat" \ authorized_keys ',principals="mekmitasdigoat"' test_one "principals key option no principals" failure "" \ authorized_keys ',principals="mekmitasdigoat"' # command= options vs. force-command in key test_one "force-command match true" success \ "-n ${USER} -Oforce-command=true" \ authorized_keys ',command="true"' test_one "force-command match true" failure \ "-n ${USER} -Oforce-command=false" \ authorized_keys ',command="false"' test_one "force-command mismatch 1" failure \ "-n ${USER} -Oforce-command=false" \ authorized_keys ',command="true"' test_one "force-command mismatch 2" failure \ "-n ${USER} -Oforce-command=true" \ authorized_keys ',command="false"' # Wrong certificate cat $OBJ/sshd_proxy_bak > $OBJ/sshd_proxy for ktype in $PLAIN_TYPES ; do t=$(kname $ktype) # Self-sign ${SSHKEYGEN} -q -s $OBJ/cert_user_key_${ktype} -I \ "regress user key for $USER" \ -n $USER $OBJ/cert_user_key_${ktype} || fatal "couldn't sign cert_user_key_${ktype}" verbose "$tid: user ${ktype} connect wrong cert" ${SSH} -i $OBJ/cert_user_key_${ktype} -F $OBJ/ssh_proxy \ somehost true >/dev/null 2>&1 if [ $? -eq 0 ]; then fail "ssh cert connect $ident succeeded unexpectedly" fi done rm -f $OBJ/authorized_keys_$USER $OBJ/user_ca_key* $OBJ/cert_user_key* rm -f $OBJ/authorized_principals_$USER