chrooting 用户在使用 sftp 时导致“连接关闭”消息

Question

首先，我是一个 linux 新手，所以请不要假设太多的知识。我正在使用 CentOS 5.8（最终版）并使用 OpenSSH 版本 5.8p1。

我已经创建了一个用户playwithbits，我正在尝试将chroot他们转到该目录home/nginx/domains/playwithbits/public

我match在我的sshd_config文件中使用以下语句：

Match group web-root-locked
         ChrootDirectory /home/nginx/domains/%u/public
         X11Forwarding no
         AllowTcpForwarding no
         ForceCommand /usr/libexec/openssh/sftp-server

# id playwithbits 返回： uid=504(playwithbits) gid=504(playwithbits) groups=504(playwithbits),507(web-root-locked)

我已将用户的主目录更改为： home/nginx/domains/playwithbits/public

现在，当我尝试与该用户进行 sftp 连接时，我立即收到以下消息： connection closed

有谁知道我做错了什么？

编辑：遵循@Dennis Williamson 的建议，我已在调试模式下进行连接（我认为......如果我错了，请纠正我）。

通过使用chmod递归将所有文件的权限直接设置为 700，我取得了一些进展。现在，当我尝试登录时收到以下消息（仍然拒绝连接）：

Connection from [My ip address] port 38737
debug1: Client protocol version 2.0; client software version OpenSSH_5.6
debug1: match: OpenSSH_5.6 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.8
debug1: permanently_set_uid: 74/74
debug1: list_hostkey_types: ssh-rsa,ssh-dss
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST received
debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT
debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: KEX done
debug1: userauth-request for user playwithbits service ssh-connection method none
debug1: attempt 0 failures 0
debug1: user playwithbits matched group list web-root-locked at line 91
debug1: PAM: initializing for "playwithbits"
debug1: PAM: setting PAM_RHOST to [My host info]
debug1: PAM: setting PAM_TTY to "ssh"
debug1: userauth-request for user playwithbits service ssh-connection method password
debug1: attempt 1 failures 0
debug1: PAM: password authentication accepted for playwithbits
debug1: do_pam_account: called
Accepted password for playwithbits from [My ip address] port 38737 ssh2
debug1: monitor_child_preauth: playwithbits has been authenticated by privileged process
debug1: SELinux support disabled
debug1: PAM: establishing credentials
User child is on pid 3942
debug1: PAM: establishing credentials
Changed root directory to "/home/nginx/domains/playwithbits/public"
debug1: permanently_set_uid: 504/504
debug1: Entering interactive session for SSH2.
debug1: server_init_dispatch_20
debug1: server_input_channel_open: ctype session rchan 0 win 2097152 max 32768
debug1: input_session_request
debug1: channel 0: new [server-session]
debug1: session_new: session 0
debug1: session_open: channel 0
debug1: session_open: session 0: link with channel 0
debug1: server_input_channel_open: confirm session
debug1: server_input_global_request: rtype no-more-sessions@openssh.com want_reply 0
debug1: server_input_channel_req: channel 0 request env reply 0
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req env
debug1: server_input_channel_req: channel 0 request subsystem reply 1
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req subsystem
subsystem request for sftp by user playwithbits
debug1: subsystem: cannot stat /usr/libexec/openssh/sftp-server: Permission denied
debug1: subsystem: exec() /usr/libexec/openssh/sftp-server
debug1: Forced command (config) '/usr/libexec/openssh/sftp-server'
debug1: session_new: session 0
debug1: Received SIGCHLD.
debug1: session_by_pid: pid 3943
debug1: session_exit_message: session 0 channel 0 pid 3943
debug1: session_exit_message: release channel 0
debug1: session_by_channel: session 0 channel 0
debug1: session_close_by_channel: channel 0 child 0
debug1: session_close: session 0 pid 0
debug1: channel 0: free: server-session, nchannels 1
Received disconnect from [My ip address]: 11: disconnected by user
debug1: do_cleanup
debug1: do_cleanup
debug1: PAM: cleanup
debug1: PAM: closing session
debug1: PAM: deleting credentials

Answer 1

当从服务器端调试时，这些问题总是更容易。我建议在调试模式下启动第二台服务器，例如/usr/sbin/sshd -p 2222 -d. 然后您可以使用 连接您的客户端sftp -P 2222 user@remotehost，并期望服务器告诉您断开连接的原因。很可能存在权限问题，我的猜测是您没有满足根目录拥有主目录的要求。