Ubuntu WSL下GitHub SSH认证失败：Permission denied (publickey)

之前在Ubuntu WSL上配置了两个GitHub账号（学校.edu账号及个人账号），通过git config user.name/user.email切换账号，提交代码、克隆仓库均正常。后续安装KDE.org的GitLab并完成仓库复刻与SSH认证后，尝试修改全局配置时强制退出（:q!），重启电脑后使用个人账号推送代码出现「Permission denied (publickey)」错误。按Ubuntu社区教程设置.ssh目录700权限、密钥文件600权限无效；重新生成GitLab和GitHub的SSH密钥也未解决问题。

.ssh/config配置片段 #

...

#personal account
Host github.com-victoriaemily
    HostName github.com
    User victoriaemily
    IdentityFile ~/.ssh/victoriaemily
    IdentitiesOnly yes

.ssh目录文件说明 #

从提供的截图可见，目录下包含victoriaemily（私钥）、victoriaemily.pub（公钥）、config、known_hosts等文件。

ssh -vT git@github.com调试日志 #

OpenSSH_8.2p1 Ubuntu-4ubuntu0.5, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /home/victoriaemily/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to github.com [140.82.114.4] port 22.
debug1: Connection established.
debug1: identity file /home/victoriaemily/.ssh/id_rsa type -1
debug1: identity file /home/victoriaemily/.ssh/id_rsa-cert type -1
...
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.5
debug1: Remote protocol version 2.0, remote software version babeld-4ce3b487
debug1: no match: babeld-4ce3b487
debug1: Authenticating to github.com:22 as 'git'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:p2QAMXNIC1TJYWeIOttrVc98/R1BUFWu3/LiyKgUfQM
debug1: Host 'github.com' is known and matches the ECDSA host key.
debug1: Found key in /home/victoriaemily/.ssh/known_hosts:3
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey in after 134217728 blocks
debug1: Will attempt key: /home/victoriaemily/.ssh/id_rsa
debug1: Will attempt key: /home/victoriaemily/.ssh/id_dsa
...
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519-cert-v01@openssh...
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /home/victoriaemily/.ssh/id_rsa
debug1: Trying private key: /home/victoriaemily/.ssh/id_dsa
...
debug1: No more authentication methods to try.
git@github.com: Permission denied (publickey).

1. 修复SSH配置匹配问题 #

从调试日志可知，执行ssh -vT git@github.com时，SSH未匹配到github.com-victoriaemily的配置条目，只会尝试默认密钥文件（id_rsa、id_dsa等），不会加载你指定的victoriaemily密钥。可二选一修复：

方式A：修改仓库远程地址 #

针对个人账号的仓库，将远程地址替换为config中定义的Host别名：

git remote set-url origin git@github.com-victoriaemily:你的个人用户名/仓库名.git

后续推送时，SSH会自动加载对应的victoriaemily密钥。

方式B：修改.ssh/config匹配github.com #

若想直接使用git@github.com，在config中新增或修改条目：

Host github.com
    HostName github.com
    User git
    IdentityFile ~/.ssh/victoriaemily
    IdentitiesOnly yes

注意：若需保留学校账号，需给学校账号单独设置Host别名（如github.com-school），并让学校仓库使用对应的远程地址。

2. 验证SSH连接 #

修改后执行对应命令验证：

• 方式A：ssh -vT git@github.com-victoriaemily
• 方式B：ssh -vT git@github.com
  查看日志是否加载了~/.ssh/victoriaemily密钥且认证成功。

3. 确认Git账号配置 #

虽然SSH认证与user.name/email无关，但需确保当前仓库的配置正确：

# 查看当前仓库配置
git config user.name
git config user.email
# 配置错误则修正
git config user.name "你的个人账号用户名"
git config user.email "你的个人账号邮箱"

4. 重置SSH代理（可选） #

若之前启动过ssh-agent缓存了旧密钥，重启代理并重新加载密钥：

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/victoriaemily

再重新测试SSH连接。

内容的提问来源于stack exchange，提问作者Victoria Chen