https://bugzilla.mindrot.org/show_bug.cgi?id=3351
Bug ID: 3351 Summary: RSA SHA256 certificates no longer work Product: Portable OpenSSH Version: 8.8p1 Hardware: All OS: All Status: NEW Severity: normal Priority: P5 Component: ssh Assignee: unassigned-b...@mindrot.org Reporter: denisen...@gmail.com RSA SHA256 certificate authentication stopped working in 8.8. It looks like RSA SHA256 certificates are identified as ssh-rsa-cert-...@openssh.com instead of as rsa-sha2-256-cert-...@openssh.com and current allow list does not have ssh-rsa-cert-...@openssh.com on it, resulting in rejection of such certificates by the client. The root cause seems to be in misidentification of SHA256 certificates as sh-rsa-cert-...@openssh.com certificates. Workaround is to add "PubkeyAcceptedKeyTypes +ssh-rsa-cert-...@openssh.com" into client ssh config, but this doesn't seem right, since certificate is actually SHA256 certificate and should be allowed by default. Reproduction steps: create CA key: ssh-keygen -t rsa-sha2-256 -f ca_key create user key: ssh-keygen -t rsa-sha2-256 -f user_key sign certificate using SHA256 signature: ssh-keygen -s ca_key -I "test" -z "123" -V -1w:+54w5d -t rsa-sha2-256 -n user user_key.pub copy ca_key.pub to server /etc/ssh/ca_key.pub Add following line to /etc/sshd_config: TrustedUserCAKeys /etc/ssh/ca_key.pub restart sshd: sudo service sshd restart add test user: sudo useradd user Back on Client run: ssh -i user_key user@<server-host> This fails with: user@<server-host>: Permission denied (publickey,gssapi-keyex,gssapi-with-mic). -- You are receiving this mail because: You are watching the assignee of the bug. _______________________________________________ openssh-bugs mailing list openssh-bugs@mindrot.org https://lists.mindrot.org/mailman/listinfo/openssh-bugs