diff --color -rup a/regress/hostkey-agent.sh b/regress/hostkey-agent.sh --- a/regress/hostkey-agent.sh 2021-08-20 06:03:49.000000000 +0200 +++ b/regress/hostkey-agent.sh 2022-07-14 11:58:12.172786060 +0200 @@ -13,8 +13,12 @@ r=$? grep -vi 'hostkey' $OBJ/sshd_proxy > $OBJ/sshd_proxy.orig echo "HostKeyAgent $SSH_AUTH_SOCK" >> $OBJ/sshd_proxy.orig +PUBKEY_ACCEPTED_ALGOS=`$SSH -G "example.com" | \ + grep -i "PubkeyAcceptedAlgorithms" | cut -d ' ' -f2- | tr "," "|"` +SSH_ACCEPTED_KEYTYPES=`echo "$SSH_KEYTYPES" | egrep "$PUBKEY_ACCEPTED_ALGOS"` + trace "load hostkeys" -for k in $SSH_KEYTYPES ; do +for k in $SSH_ACCEPTED_KEYTYPES ; do ${SSHKEYGEN} -qt $k -f $OBJ/agent-key.$k -N '' || fatal "ssh-keygen $k" ( printf 'localhost-with-alias,127.0.0.1,::1 ' @@ -31,7 +35,7 @@ cp $OBJ/known_hosts.orig $OBJ/known_host unset SSH_AUTH_SOCK for ps in yes; do - for k in $SSH_KEYTYPES ; do + for k in $SSH_ACCEPTED_KEYTYPES ; do verbose "key type $k privsep=$ps" cp $OBJ/sshd_proxy.orig $OBJ/sshd_proxy echo "UsePrivilegeSeparation $ps" >> $OBJ/sshd_proxy diff --color -rup a/sshconnect2.c b/sshconnect2.c --- a/sshconnect2.c 2022-07-14 10:10:07.262975710 +0200 +++ b/sshconnect2.c 2022-07-14 10:10:32.068452067 +0200 @@ -222,6 +222,7 @@ ssh_kex2(struct ssh *ssh, char *host, st { char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; char *s, *all_key; + char *hostkeyalgs = NULL, *pkalg = NULL; char *prop_kex = NULL, *prop_enc = NULL, *prop_hostkey = NULL; int r, use_known_hosts_order = 0; @@ -264,14 +265,19 @@ ssh_kex2(struct ssh *ssh, char *host, st myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; if (use_known_hosts_order) { /* Query known_hosts and prefer algorithms that appear there */ - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = prop_hostkey = - compat_pkalg_proposal(ssh, - order_hostkeyalgs(host, hostaddr, port, cinfo)); + if ((hostkeyalgs = order_hostkeyalgs(host, hostaddr, port, cinfo)) == NULL) + fatal_f("order_hostkeyalgs"); + pkalg = match_filter_allowlist(hostkeyalgs, options.pubkey_accepted_algos); + free(hostkeyalgs); } else { - /* Use specified HostkeyAlgorithms exactly */ - myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = prop_hostkey = - compat_pkalg_proposal(ssh, options.hostkeyalgorithms); + /* Use specified HostkeyAlgorithms */ + pkalg = match_filter_allowlist(options.hostkeyalgorithms, options.pubkey_accepted_algos); } + if (pkalg == NULL) + fatal_f("match_filter_allowlist"); + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = prop_hostkey = + compat_pkalg_proposal(ssh, pkalg); + free(pkalg); #if defined(GSSAPI) && defined(WITH_OPENSSL) if (options.gss_keyex) {