1296853Sdes# $OpenBSD: limit-keytype.sh,v 1.4 2015/10/29 08:05:17 djm Exp $ 2285031Sdes# Placed in the Public Domain. 3285031Sdes 4285031Sdestid="restrict pubkey type" 5285031Sdes 6285031Sdesrm -f $OBJ/authorized_keys_$USER $OBJ/user_ca_key* $OBJ/user_key* 7285031Sdesrm -f $OBJ/authorized_principals_$USER $OBJ/cert_user_key* 8285031Sdes 9285031Sdesmv $OBJ/sshd_proxy $OBJ/sshd_proxy.orig 10285031Sdesmv $OBJ/ssh_proxy $OBJ/ssh_proxy.orig 11285031Sdes 12285031Sdes# Create a CA key 13285031Sdes${SSHKEYGEN} -q -N '' -t ed25519 -f $OBJ/user_ca_key ||\ 14285031Sdes fatal "ssh-keygen failed" 15285031Sdes 16285031Sdes# Make some keys and a certificate. 17285031Sdes${SSHKEYGEN} -q -N '' -t ed25519 -f $OBJ/user_key1 || \ 18285031Sdes fatal "ssh-keygen failed" 19285031Sdes${SSHKEYGEN} -q -N '' -t rsa -f $OBJ/user_key2 || \ 20285031Sdes fatal "ssh-keygen failed" 21285031Sdes${SSHKEYGEN} -q -N '' -t rsa -f $OBJ/user_key3 || \ 22285031Sdes fatal "ssh-keygen failed" 23296853Sdes${SSHKEYGEN} -q -N '' -t dsa -f $OBJ/user_key4 || \ 24296853Sdes fatal "ssh-keygen failed" 25285031Sdes${SSHKEYGEN} -q -s $OBJ/user_ca_key -I "regress user key for $USER" \ 26285031Sdes -z $$ -n ${USER},mekmitasdigoat $OBJ/user_key3 || 27285031Sdes fatal "couldn't sign user_key1" 28285031Sdes# Copy the private key alongside the cert to allow better control of when 29285031Sdes# it is offered. 30285031Sdesmv $OBJ/user_key3-cert.pub $OBJ/cert_user_key3.pub 31285031Sdes 32285031Sdesgrep -v IdentityFile $OBJ/ssh_proxy.orig > $OBJ/ssh_proxy 33285031Sdes 34285031Sdesopts="-oProtocol=2 -F $OBJ/ssh_proxy -oIdentitiesOnly=yes" 35296853Sdescertopts="$opts -i $OBJ/user_key3 -oCertificateFile=$OBJ/cert_user_key3.pub" 36285031Sdes 37285031Sdesecho mekmitasdigoat > $OBJ/authorized_principals_$USER 38285031Sdescat $OBJ/user_key1.pub > $OBJ/authorized_keys_$USER 39285031Sdescat $OBJ/user_key2.pub >> $OBJ/authorized_keys_$USER 40285031Sdes 41285031Sdesprepare_config() { 42285031Sdes ( 43285031Sdes grep -v "Protocol" $OBJ/sshd_proxy.orig 44285031Sdes echo "Protocol 2" 45285031Sdes echo "AuthenticationMethods publickey" 46285031Sdes echo "TrustedUserCAKeys $OBJ/user_ca_key.pub" 47285031Sdes echo "AuthorizedPrincipalsFile $OBJ/authorized_principals_%u" 48285031Sdes for x in "$@" ; do 49285031Sdes echo "$x" 50285031Sdes done 51285031Sdes ) > $OBJ/sshd_proxy 52285031Sdes} 53285031Sdes 54285031Sdesprepare_config 55285031Sdes 56285031Sdes# Check we can log in with all key types. 57296853Sdes${SSH} $certopts proxy true || fatal "cert failed" 58285031Sdes${SSH} $opts -i $OBJ/user_key1 proxy true || fatal "key1 failed" 59285031Sdes${SSH} $opts -i $OBJ/user_key2 proxy true || fatal "key2 failed" 60285031Sdes 61285031Sdes# Allow plain Ed25519 and RSA. The certificate should fail. 62296853Sdesverbose "allow rsa,ed25519" 63285031Sdesprepare_config "PubkeyAcceptedKeyTypes ssh-rsa,ssh-ed25519" 64296853Sdes${SSH} $certopts proxy true && fatal "cert succeeded" 65285031Sdes${SSH} $opts -i $OBJ/user_key1 proxy true || fatal "key1 failed" 66285031Sdes${SSH} $opts -i $OBJ/user_key2 proxy true || fatal "key2 failed" 67285031Sdes 68285031Sdes# Allow Ed25519 only. 69296853Sdesverbose "allow ed25519" 70285031Sdesprepare_config "PubkeyAcceptedKeyTypes ssh-ed25519" 71296853Sdes${SSH} $certopts proxy true && fatal "cert succeeded" 72285031Sdes${SSH} $opts -i $OBJ/user_key1 proxy true || fatal "key1 failed" 73285031Sdes${SSH} $opts -i $OBJ/user_key2 proxy true && fatal "key2 succeeded" 74285031Sdes 75285031Sdes# Allow all certs. Plain keys should fail. 76296853Sdesverbose "allow cert only" 77285031Sdesprepare_config "PubkeyAcceptedKeyTypes ssh-*-cert-v01@openssh.com" 78296853Sdes${SSH} $certopts proxy true || fatal "cert failed" 79285031Sdes${SSH} $opts -i $OBJ/user_key1 proxy true && fatal "key1 succeeded" 80285031Sdes${SSH} $opts -i $OBJ/user_key2 proxy true && fatal "key2 succeeded" 81285031Sdes 82296853Sdes# Allow RSA in main config, Ed25519 for non-existent user. 83296853Sdesverbose "match w/ no match" 84296853Sdesprepare_config "PubkeyAcceptedKeyTypes ssh-rsa" \ 85296853Sdes "Match user x$USER" "PubkeyAcceptedKeyTypes +ssh-ed25519" 86296853Sdes${SSH} $certopts proxy true && fatal "cert succeeded" 87296853Sdes${SSH} $opts -i $OBJ/user_key1 proxy true && fatal "key1 succeeded" 88296853Sdes${SSH} $opts -i $OBJ/user_key2 proxy true || fatal "key2 failed" 89296853Sdes 90296853Sdes# Allow only DSA in main config, Ed25519 for user. 91296853Sdesverbose "match w/ matching" 92296853Sdesprepare_config "PubkeyAcceptedKeyTypes ssh-dss" \ 93296853Sdes "Match user $USER" "PubkeyAcceptedKeyTypes +ssh-ed25519" 94296853Sdes${SSH} $certopts proxy true || fatal "cert failed" 95296853Sdes${SSH} $opts -i $OBJ/user_key1 proxy true || fatal "key1 failed" 96296853Sdes${SSH} $opts -i $OBJ/user_key4 proxy true && fatal "key4 succeeded" 97296853Sdes 98