Remediating ospp on RHEL-10 results in sshd refusing connections

[comps]

Description of problem:

oscap xccdf eval --profile xccdf_org.ssgproject.content_profile_ospp --progress --report remediation.html --remediate remediation-ds.xml

results in a system that boots, but when I try to ssh into it, it seems to fail due to crypto policies:

+ ssh -vvvvv -i /var/lib/libvirt/images/contest.sshkey [email protected]
OpenSSH_9.6p1, OpenSSL 3.2.2 4 Jun 2024
debug1: Reading configuration data /etc/ssh/ssh_config
debug3: /etc/ssh/ssh_config line 55: Including file /etc/ssh/ssh_config.d/50-redhat.conf depth 0
debug1: Reading configuration data /etc/ssh/ssh_config.d/50-redhat.conf
debug2: checking match for 'final all' host 192.168.121.140 originally 192.168.121.140
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 3: not matched 'final'
debug2: match not found
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 5: Including file /etc/crypto-policies/back-ends/openssh.config depth 1 (parse only)
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug3: gss kex names ok: [gss-curve25519-sha256-,gss-nistp256-sha256-,gss-group14-sha256-,gss-group16-sha512-]
debug3: kex names ok: [curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512]
debug1: configuration requests final Match pass
debug2: resolve_canonicalize: hostname 192.168.121.140 is address
debug1: re-parsing configuration
debug1: Reading configuration data /etc/ssh/ssh_config
debug3: /etc/ssh/ssh_config line 55: Including file /etc/ssh/ssh_config.d/50-redhat.conf depth 0
debug1: Reading configuration data /etc/ssh/ssh_config.d/50-redhat.conf
debug2: checking match for 'final all' host 192.168.121.140 originally 192.168.121.140
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 3: matched 'final'
debug2: match found
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 5: Including file /etc/crypto-policies/back-ends/openssh.config depth 1
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug3: gss kex names ok: [gss-curve25519-sha256-,gss-nistp256-sha256-,gss-group14-sha256-,gss-group16-sha512-]
debug3: kex names ok: [curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512]
debug3: channel_clear_timeouts: clearing
debug3: ssh_connect_direct: entering
debug1: Connecting to 192.168.121.140 [192.168.121.140] port 22.
debug3: set_sock_tos: set socket 3 IP_TOS 0x48
debug1: Connection established.
debug1: identity file /var/lib/libvirt/images/contest.sshkey type 0
debug1: identity file /var/lib/libvirt/images/contest.sshkey-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_9.6
debug1: Remote protocol version 2.0, remote software version OpenSSH_9.6
debug1: compat_banner: match: OpenSSH_9.6 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 192.168.121.140:22 as 'root'
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts2: No such file or directory
debug3: order_hostkeyalgs: no algorithms matched; accept original
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,ext-info-c,[email protected]
debug2: host key algorithms: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],rsa-sha2-512,rsa-sha2-256
debug2: ciphers ctos: [email protected],[email protected],aes256-ctr,[email protected],aes128-ctr
debug2: ciphers stoc: [email protected],[email protected],aes256-ctr,[email protected],aes128-ctr
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha1,[email protected],hmac-sha2-512
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha1,[email protected],hmac-sha2-512
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,ext-info-s,[email protected]
debug2: host key algorithms: rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256
debug2: ciphers ctos: [email protected],[email protected],aes256-ctr,[email protected],aes128-ctr
debug2: ciphers stoc: [email protected],[email protected],aes256-ctr,[email protected],aes128-ctr
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha1,[email protected],hmac-sha2-512
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha1,[email protected],hmac-sha2-512
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug3: kex_choose_conf: will use strict KEX ordering
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: curve25519-sha256 need=32 dh_need=32
debug1: kex: curve25519-sha256 need=32 dh_need=32
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
Connection closed by 192.168.121.140 port 22

commenting out the Include in /etc/ssh/sshd_config.d/40-redhat-crypto-policies.conf gets me a working ssh connection.

Other profiles (STIG) seem to work after I explicitly started generating RSA keys (RHEL-10 defaults to non-RSA), but that's with the FIPS crypto policies. The ospp profile is special because it (as far as I know) uses FIPS:OSPP, which might be somehow broken.

Or maybe the bug is in how the content uses it. More investigation is likely needed.

SCAP Security Guide Version:

520a196

Additional Information/Debugging Steps:

I'm attaching the only artifact I have - the remediation HTML report. Not sure if it helps anything.
remediation.html.gz

[mildas]

Should we add there BLOCKER label? @comps @Mab879

[Mab879]

Bricking ssh isn't great. We should have a solution even if this isn't our fault.

+1 to blocker

[Mab879]

Since the OSPP profile is no longer in RHEL 10 the blocker label is not needed.

[matusmarhefka]

This was fixed by #12369

The issue was that OSPP control file for RHEL10 selected wrong rules and these were preventing SSH access.