From e8622f8c21e461eeceb2cc6ebb79287b7b044085 Mon Sep 17 00:00:00 2001 From: Zoltan Fridrich Date: Tue, 12 Jul 2022 16:50:40 +0200 Subject: [PATCH] Don't propose disallowed algorithms during hostkey negotiation Resolves: rhbz#2068423 Signed-off-by: Zoltan Fridrich --- openssh-8.7p1-negotiate-supported-algs.patch | 63 ++++++++++++++++++++ openssh.spec | 11 +++- 2 files changed, 73 insertions(+), 1 deletion(-) create mode 100644 openssh-8.7p1-negotiate-supported-algs.patch diff --git a/openssh-8.7p1-negotiate-supported-algs.patch b/openssh-8.7p1-negotiate-supported-algs.patch new file mode 100644 index 0000000..2fb9297 --- /dev/null +++ b/openssh-8.7p1-negotiate-supported-algs.patch @@ -0,0 +1,63 @@ +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) { diff --git a/openssh.spec b/openssh.spec index 5627a63..6f41f0a 100644 --- a/openssh.spec +++ b/openssh.spec @@ -51,7 +51,7 @@ # Do not forget to bump pam_ssh_agent_auth release if you rewind the main package release to 1 %global openssh_ver 8.7p1 -%global openssh_rel 15 +%global openssh_rel 16 %global pam_ssh_agent_ver 0.10.4 %global pam_ssh_agent_rel 4 @@ -246,6 +246,10 @@ Patch1004: openssh-8.7p1-gssapi-auth.patch # d9dbb5d9a0326e252d3c7bc13beb9c2434f59409 # fdb1d58d0d3888b042e5a500f6ce524486aaf782 Patch1005: openssh-8.7p1-host-based-auth.patch +# Don't propose disallowed algorithms during hostkey negotiation +# upstream MR: +# https://github.com/openssh/openssh-portable/pull/323 +Patch1006: openssh-8.7p1-negotiate-supported-algs.patch License: BSD Requires: /sbin/nologin @@ -440,6 +444,7 @@ popd %patch1003 -p1 -b .mem-leak %patch1004 -p1 -b .gssapi-auth %patch1005 -p1 -b .host-based-auth +%patch1006 -p1 -b .negotiate-supported-algs %patch100 -p1 -b .coverity @@ -720,6 +725,10 @@ test -f %{sysconfig_anaconda} && \ %endif %changelog +* Thu Jul 14 2022 Zoltan Fridrich - 8.7p1-16 +- Don't propose disallowed algorithms during hostkey negotiation + Resolves: rhbz#2068423 + * Thu Jul 14 2022 Dmitry Belyavskiy - 8.7p1-15 - Disable ed25519 and ed25519-sk keys in FIPS mode Related: rhbz#2087915