MacOS下GitHub多SSH密钥配置异常，个人密钥匹配企业账户求助

问题现象 #

配置了两个GitHub账户（个人/企业）及对应独立SSH密钥，SSH配置文件如下：

# * GitHub CKO SSH Key
Host github-enterprise
  HostName github.com
  AddKeysToAgent yes
  UseKeychain yes
  User git
  IdentityFile ~/.ssh/id_ed25519_github

# * GitHub Personal SSH Key
Host github-personal
  HostName github.com
  AddKeysToAgent yes
  UseKeychain yes
  User git
  IdentityFile ~/.ssh/gh_mervinhemaraju_ed25519

此前正常使用近一个月，近期推送个人仓库代码时触发权限拒绝，测试SSH连接发现：

ssh -T git@github-personal
# 返回：Hi mervin-hemaraju-enterprise! You've successfully authenticated, but GitHub does not provide shell access.

ssh -T git@github-enterprise
# 返回：Hi mervin-hemaraju-cko! You've successfully authenticated, but GitHub does not provide shell access.

个人Host(github-personal)错误匹配到企业账户身份。

解决步骤 #

1. 清空SSH Agent缓存并重新加载密钥 #

MacOS的SSH Agent可能缓存了旧的密钥优先级，导致错误匹配：

# 清空所有缓存的SSH密钥
ssh-add -D

# 分别添加两个账户的密钥
ssh-add ~/.ssh/id_ed25519_github
ssh-add ~/.ssh/gh_mervinhemaraju_ed25519

2. 修正SSH配置的优先级 #

确保全局配置不会覆盖Host专属设置，在~/.ssh/config最顶部添加全局规则，再保留原有Host配置：

# 全局配置
Host *
  AddKeysToAgent yes
  UseKeychain yes

# * GitHub CKO SSH Key
Host github-enterprise
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_ed25519_github

# * GitHub Personal SSH Key
Host github-personal
  HostName github.com
  User git
  IdentityFile ~/.ssh/gh_mervinhemaraju_ed25519

3. 检查并修正密钥文件权限 #

MacOS对SSH密钥权限要求严格，必须确保密钥文件和目录权限正确：

# 设置.ssh目录权限为700
chmod 700 ~/.ssh

# 设置两个密钥文件权限为600
chmod 600 ~/.ssh/id_ed25519_github
chmod 600 ~/.ssh/gh_mervinhemaraju_ed25519

4. 验证个人仓库的远程地址配置 #

确保个人仓库的远程地址使用了github-personal Host，而非直接指向github.com：

# 查看当前远程地址
git remote -v

# 如果不是正确的Host，修改远程地址
git remote set-url origin git@github-personal:mervinhemaraju/your-personal-repo.git

5. 重新测试SSH连接 #

执行以下命令验证身份匹配是否恢复正常：

ssh -T git@github-personal
# 应返回：Hi mervinhemaraju! You've successfully authenticated, but GitHub does not provide shell access.

ssh -T git@github-enterprise
# 应返回：Hi mervin-hemaraju-cko! You've successfully authenticated, but GitHub does not provide shell access.

内容的提问来源于stack exchange，提问作者Mervin Hemaraju