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recently we started upgrading from ubuntu18.04 fips to ubuntu 20.04 fips image, and I used aws marketplace image ubuntu-pro-fips-server/images/hvm-ssd/ubuntu-focal-20.04-amd64-pro-fips-server, and we use Netfilx bless tool for ssh and it still works for 18.04 FIPS and 20.04 for non FIPS too,

But I'm getting "userauth_pubkey: certificate signature algorithm ssh-rsa: signature algorithm not supported [preauth]",

but to test this bless tool, I created the cert manually with same algorithm ssh-rsa and same bits and I'm able ssh with that keys(ssh with signed CA certs option I used), but not with bless keys

root@hostname:/var/snap/amazon-ssm-agent/6563# ssh -Q key
ssh-ed25519
[email protected]
[email protected]
[email protected]
ssh-rsa
ssh-dss
ecdsa-sha2-nistp256
ecdsa-sha2-nistp384
ecdsa-sha2-nistp521
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]

I'm getting this error from bastion No more authentication methods to try. ubuntu@graviton-test-bastion-20-fips-0c3f60d2: Permission denied (publickey).

SSH SERVER LOGS:

Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11415]: debug1: Forked child 11417.
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: Set /proc/self/oom_score_adj to 0
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: rexec start in 5 out 5 newsock 5 pipe 7 sock 8
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: inetd sockets after dupping: 4, 4
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: Connection from 10.X.X.X port 16130 on 10.X.X.X port 22 rdomain ""
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.fips.0.2.1
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: Remote protocol version 2.0, remote software version OpenSSH_7.6p1 Ubuntu-4ubuntu0.7
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: match: OpenSSH_7.6p1 Ubuntu-4ubuntu0.7 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: permanently_set_uid: 109/65534 [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: list_hostkey_types: rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519 [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: SSH2_MSG_KEXINIT sent [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: SSH2_MSG_KEXINIT received [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: kex: algorithm: curve25519-sha256 [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: kex: host key algorithm: ecdsa-sha2-nistp256 [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: expecting SSH2_MSG_KEX_ECDH_INIT [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: rekey out after 134217728 blocks [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: SSH2_MSG_NEWKEYS sent [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: Sending SSH2_MSG_EXT_INFO [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: expecting SSH2_MSG_NEWKEYS [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: SSH2_MSG_NEWKEYS received [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: rekey in after 134217728 blocks [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: KEX done [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: userauth-request for user ubuntu service ssh-connection method none [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: attempt 0 failures 0 [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: PAM: initializing for "ubuntu"
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: PAM: setting PAM_RHOST to "10.X.X.X"
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: PAM: setting PAM_TTY to "ssh"
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: userauth_send_banner: sent [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: userauth-request for user ubuntu service ssh-connection method publickey [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: attempt 1 failures 0 [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: userauth_pubkey: test pkalg rsa-sha2-512 pkblob RSA SHA256:eDIkE2MsPXLsxp5tG5jeQLQ+E/tdypLNxQk4nBEEfUM [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: temporarily_use_uid: 1000/1000 (e=0/0)
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: trying public key file /home/ubuntu/.ssh/authorized_keys
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: fd 5 clearing O_NONBLOCK
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: restore_uid: 0/0
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: temporarily_use_uid: 1000/1000 (e=0/0)
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: trying public key file /home/ubuntu/.ssh/authorized_keys2
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: Could not open authorized keys '/home/ubuntu/.ssh/authorized_keys2': No such file or directory
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: restore_uid: 0/0
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: temporarily_use_uid: 112/65534 (e=0/0)
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: restore_uid: 0/0
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: temporarily_use_uid: 112/65534 (e=0/0)
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: AuthorizedKeysCommand /usr/share/ec2-instance-connect/eic_run_authorized_keys ubuntu SHA256:XXXXXpLNxQk4nBEEfUM failed, status 22
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: restore_uid: 0/0
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: Failed publickey for ubuntu from 10.X.X.X port 16130 ssh2: RSA SHA256:XXXXXXXXXEEfUM
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: userauth-request for user ubuntu service ssh-connection method publickey [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: debug1: attempt 2 failures 1 [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: userauth_pubkey: certificate signature algorithm ssh-rsa: signature algorithm not supported [preauth]
Jul  1 04:09:32 graviton-test-bastion-20-fips-0c3f60d2 sshd[11417]: Connection closed by authenticating user ubuntu 10.88.67.39 port 16130 [preauth]
Luuk
  • 150
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  • Because of: "**ssh-rsa: signature algorithm not supported**", see: [Ubuntu 22.04 SSH the RSA key isn't working since upgrading from 20.04](https://askubuntu.com/questions/1409105/ubuntu-22-04-ssh-the-rsa-key-isnt-working-since-upgrading-from-20-04) and/or [SSH without password does not work after upgrading from 18.04 to 22.04](https://askubuntu.com/questions/1404049/ssh-without-password-does-not-work-after-upgrading-from-18-04-to-22-04) – Luuk Jul 02 '23 at 16:10

0 Answers0