Fedora 33 ssh RSA 密钥认证 Permission denied 失败问题
分类：System 标签：Ssh
WHAT
升级到 Fedora 33 后，发现 ssh 密钥认证登录远程服务器失败，提示 Permission denied (publickey).
ssh -vvv user@10.16.2.99 认证过程有识别到 ~/.ssh/id_rsa 但是并未成功：
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/user/.ssh/id_rsa RSA SHA256:... explicit agent
debug1: send_pubkey_test: no mutual signature algorithm
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
user@10.16.2.99: Permission denied (publickey).
WHY
Fedora 33 禁用 RSA 认证算法：
https://fedoraproject.org/wiki/Changes/StrongCryptoSettings2
可以使用下面命令调整 全局 认证规则：
update-crypto-policies --set DEFAULT:FEDORA32
update-crypto-policies --set LEGACY
HOW
比较简单的方法就是在 ~/.ssh/config 启用 ssh-rsa ：
echo 'PubkeyAcceptedKeyTypes +ssh-rsa' >> ~/.ssh/config
reference
https://stackoverflow.com/questions/64640596/ssh-permission-denied-publickey-after-upgrade-fedora-33