缘起

今天在 git bash 命令行往 github push 代码的时候突然收到大大的警告信息，如下：

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that a host key has just been changed. The fingerprint for the RSA key sent by the remote host is SHA256:uNiVztksCsDhcc0u9e8BujQXVUpKZIDTMczCvj3tD2s. Please contact your system administrator. Add correct host key in **************************** to get rid of this message. Offending RSA key in ****************************:2 Host key for github.com has changed and you have requested strict checking. Host key verification failed. fatal: Could not read from remote repository. Please make sure you have the correct access rights and the repository exists.

这个仓库是用 ssh 连接作为 remote 的。

问题在哪

遂 google 之，发现就在今天 github 的 blog 发了 We updated our RSA SSH host key。

原来github在今天下午1点左右把他们的 RSA SSH 主机 key 给换了。

出现上面那个错误说明我在我的 ~/.ssh/known_hosts 里有过期的那个 key 的公钥。

解决方法

blog中给出的解决方法很简单，把 known_hosts 里的过期 key 删掉就行了：

$ ssh-keygen -R github.com

#Host github.com found: line 2
********/.ssh/known_hosts updated.
Original contents retained as **********/.ssh/known_hosts.old

然后进行任意一项连接到 remote 的操作，比如 git fetch，就会提示把新的公钥添加到我的 known_hosts 里，当然选 yes：

The authenticity of host ‘github.com (140.82.121.4)’ can’t be established. ED25519 key fingerprint is SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU. This key is not known by any other names. Are you sure you want to continue connecting (yes/no/[fingerprint])? yes Warning: Permanently added ‘github.com’ (ED25519) to the list of known hosts.

问题解决。

后记

最新的公钥在 github docs 里就可以找到 GitHub’s SSH key fingerprints 。

github.com ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOMqqnkVzrm0SdG6UOoqKLsabgH5C9okWi0dh2l9GKJl
github.com ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBEmKSENjQEezOmxkZMy7opKgwFB9nkt5YRrYMjNuG5N87uRgg6CLrbo5wAdT/y6v0mKV0U2w0WZ2YB/++Tpockg=
github.com ssh-rsa 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