Cygwin ssh：使用 id_rsa、id_rsa.pub 键访问远程主机后失去连接

Question

我的目标是以编程方式将文件从远程服务器复制到本地计算机。使用 Cygwin（服务器）和计算机 Cygwin 64 运行 Windows。

在我创建 rsa 或 dsa 密钥之前，我可以通过输入密码来复制文件

但在创建这些文件后，出现“远程主机关闭连接。丢失连接”错误

我授予以下权限：“chmod 600 .ssh/id_rsa”（在本地计算机上）和 chmod 600“.ssh/authorized_keys2”。有什么问题谁能解答我？

    $ ssh login@hiddenhost
    Connection to hiddenhost closed by remote host.
    Connection to hiddenhost closed.

    PC003370+procserver@ATMPROCSERVER ~
    $ ssh -v login@hiddenhost
    OpenSSH_7.2p2, OpenSSL 1.0.2g  1 Mar 2016
    debug1: Reading configuration data /etc/ssh_config
    debug1: Connecting to hiddenhost [hiddenhost] port 22.
    debug1: Connection established.
    debug1: identity file /home/procserver/.ssh/id_rsa type 1
    debug1: key_load_public: No such file or directory
    debug1: identity file /home/procserver/.ssh/id_rsa-cert type -1
    debug1: key_load_public: No such file or directory
    debug1: identity file /home/procserver/.ssh/id_dsa type -1
    debug1: key_load_public: No such file or directory
    debug1: identity file /home/procserver/.ssh/id_dsa-cert type -1
    debug1: key_load_public: No such file or directory
    debug1: identity file /home/procserver/.ssh/id_ecdsa type -1
    debug1: key_load_public: No such file or directory
    debug1: identity file /home/procserver/.ssh/id_ecdsa-cert type -1
    debug1: key_load_public: No such file or directory
    debug1: identity file /home/procserver/.ssh/id_ed25519 type -1
    debug1: key_load_public: No such file or directory
    debug1: identity file /home/procserver/.ssh/id_ed25519-cert type -1
    debug1: Enabling compatibility mode for protocol 2.0
    debug1: Local version string SSH-2.0-OpenSSH_7.2
    debug1: Remote protocol version 2.0, remote software version OpenSSH_7.1
    debug1: match: OpenSSH_7.1 pat OpenSSH* compat 0x04000000
    debug1: Authenticating to hiddenhost:22 as 'login'
    debug1: SSH2_MSG_KEXINIT sent
    debug1: SSH2_MSG_KEXINIT received
    debug1: kex: algorithm: curve25519-sha256@libssh.org
    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:TS6tXfpxXyW/KeIWFnvxCsmEhHy8
    8NyoBA3DdOHzjFw
    debug1: Host 'hiddenhost' is known and matches the ECDSA host key.
    debug1: Found key in /home/procserver/.ssh/known_hosts:1
    debug1: rekey after 134217728 blocks
    debug1: SSH2_MSG_NEWKEYS sent
    debug1: expecting SSH2_MSG_NEWKEYS
    debug1: rekey after 134217728 blocks
    debug1: SSH2_MSG_NEWKEYS received
    debug1: SSH2_MSG_SERVICE_ACCEPT received
    debug1: Authentications that can continue: publickey,password,keyboard-interacti
    ve
    debug1: Next authentication method: publickey
    debug1: Offering RSA public key: /home/procserver/.ssh/id_rsa
    debug1: Authentication succeeded (publickey).
    Authenticated to hiddenhost ([hiddenhost]:22).
    debug1: channel 0: new [client-session]
    debug1: Requesting no-more-sessions@openssh.com
    debug1: Entering interactive session.
    debug1: pledge: network
    debug1: channel 0: free: client-session, nchannels 1
    Connection to hiddenhost closed by remote host.
    Connection to hiddenhost closed.
    Transferred: sent 1944, received 1312 bytes, in 0.0 seconds
    Bytes per second: sent 647995.5, received 437330.3
    debug1: Exit status -1

    PC003370+procserver@ATMPROCSERVER ~
    $

Answer 1

万岁！！！！

我们找到了解决方案。

所有原因都在于拥有 /var/empty/ 文件夹。我们尝试在调试模式下启动服务器...然后发现这篇文章：

" 如果您正在调试 SSH 连接，您可能需要手动运行 sshd（而不是作为服务）并启用调试输出。这样做可以让您准确跟踪无法建立连接的原因。但是，如果您尝试手动运行 sshd，您可能会收到以下消息。

% cygrunsrv.exe --stop sshd

% /usr/sbin/sshd.exe -D

无法加载主机密钥：/etc/ssh_host_ecdsa_key /var/empty 必须由 root 拥有，而不是组或全局可写。

要解决此问题，请将启动 sshd 服务的用户设为 /var/empty 的所有者。

% ls -ld /var/empty

drwxr-xr-x+ 1 cyg_server root 0 2010 年 5 月 7 日为空

% chown /var/empty

现在，重新启动 sshd。

% /usr/sbin/sshd.exe -D

当您完成调试并准备好再次将 sshd 作为服务运行时，将 /var/empty 的所有者更改为 cyg_server。

% chown cyg_server /var/empty

% cygrunsrv.exe --start sshd

注意：您必须具有管理员权限才能运行 "

Answer 2

我也遇到了同样的问题。根本原因是目录 /var/empty 不是正确的所有者，所以我这样做了： chown $uid.$gid /var/empty 问题已解决。

Answer 3

这就是为我解决问题的方法。

1. 使用以下命令在调试模式下运行 sshd

   /usr/sbin/sshd.exe -D -dd

这给了我以下警告

> $ /usr/sbin/sshd.exe -D -dd debug2: load_server_config: filename
> /etc/sshd_config debug2: load_server_config: done config len = 285
> debug2: parse_server_config: config /etc/sshd_config len 285 debug1:
> sshd version OpenSSH_7.5, OpenSSL 1.0.2k  26 Jan 2017
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @        
> WARNING: UNPROTECTED PRIVATE KEY FILE!          @
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
> Permissions 0770 for '/etc/ssh_host_rsa_key' are too open. It is
> required that your private key files are NOT accessible by others.
> This private key will be ignored. key_load_private: bad permissions
> Could not load host key: /etc/ssh_host_rsa_key
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @        
> WARNING: UNPROTECTED PRIVATE KEY FILE!          @
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
> Permissions 0770 for '/etc/ssh_host_dsa_key' are too open. It is
> required that your private key files are NOT accessible by others.
> This private key will be ignored. key_load_private: bad permissions
> Could not load host key: /etc/ssh_host_dsa_key
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @        
> WARNING: UNPROTECTED PRIVATE KEY FILE!          @
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
> Permissions 0770 for '/etc/ssh_host_ecdsa_key' are too open. It is
> required that your private key files are NOT accessible by others.
> This private key will be ignored. key_load_private: bad permissions
> Could not load host key: /etc/ssh_host_ecdsa_key
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @        
> WARNING: UNPROTECTED PRIVATE KEY FILE!          @
> @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
> Permissions 0770 for '/etc/ssh_host_ed25519_key' are too open. It is
> required that your private key files are NOT accessible by others.
> This private key will be ignored. key_load_private: bad permissions
> Could not load host key: /etc/ssh_host_ed25519_key sshd: no hostkeys
> available -- exiting.

1. 所以我把以上文件的权限改成了600

   $ chmod 0600 /etc/ssh_host*

2. 然后再次调试命令。

   SHA256:4yqAb/GiMfMJPmIXfKz+Zw4fWOCVN7E6vUDHEtokdHk /var/empty 必须由 root 拥有，而不是组或全局可写。

然后把这个文件夹的权限改成600。

$ chmod 600 /var/empty

这解决了问题。