linux - sftp chroot 目录上的公钥授权

Question

我想将公钥授权添加到我的 sftp chroot 目录，但我总是得到:

debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/test/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey).
Couldn't read packet: Connection reset by peer

Chroot 之所以有效，是因为可以使用密码进行授权。我在这台主机上有其他帐户，没有 chroot，它可以使用这个 key 。我试了很多次，还是不行。

在服务器上的 auth.log 中只有:连接被 xxx [preauth] 关闭

这是我的目录:

ls -laR /sftp/
/sftp/:
total 12
drwxr-xr-x  3 root root 4096 May  3 16:55 .
drwxr-xr-x 23 root root 4096 May  3 14:46 ..
drwxr-xr-x  3 root root 4096 May  3 16:45 backup

/sftp/backup:
total 12
drwxr-xr-x 3 root     root      4096 May  3 16:45 .
drwxr-xr-x 3 root     root      4096 May  3 16:55 ..
drwxr-xr-x 3 backup sftpusers 4096 May  3 16:55 incoming

/sftp/backup/incoming:
total 12
drwxr-xr-x 3 backup sftpusers 4096 May  3 16:55 .
drwxr-xr-x 3 root     root      4096 May  3 16:45 ..
drwx------ 2 backup sftpusers 4096 May  3 21:06 .ssh

/sftp/backup/incoming/.ssh:
total 12
drwx------ 2 backup sftpusers 4096 May  3 21:06 .
drwxr-xr-x 3 backup sftpusers 4096 May  3 16:55 ..
-rw------- 1 backup sftpusers  391 May  3 21:06 authorized_keys

我的用户:

backup:x:1002:1003::/incoming:/usr/sbin/nologin

我的 ssh 配置:

Match Group sftpusers
  ChrootDirectory /sftp/%u
  AuthorizedKeysFile  /sftp/backup/incoming/.ssh/authorized_keys
  ForceCommand internal-sftp
  AllowTcpForwarding no
  X11Forwarding no

请帮忙。

Answer 1

我尝试了这个解决方案(将 AuthorizedKeysFile 放入 Match block 中)并且 sshd -T 提示:

/etc/ssh/sshd_config line 153: Directive 'AuthorizedKeysFile' is not allowed within a Match block

(RHEL 6.6，openssh 5.3p1-104)

解决方案:authorized_keys 文件(和用户的 .ssh 目录)必须存在于/etc/passwd 定义的主目录位置，位于 chroot 目录的外部。

例如(使用 OP 用户名/用户标识符):
/etc/密码:

backup:x:1002:1003::/home/backup:/sbin/nologin

创建目录/home/backup，归root所有
创建目录 /home/backup/.ssh，将所有权更改为备份，chmod 700/home/backup/.ssh
将 authorized_keys 文件复制到 /home/backup/.ssh，chmod 400 authorized_keys

ls -laR /home

/home:
total 12
drwxr-xr-x 3 root     root      4096 Jul  9 12:25 .
drwxr-xr-x 3 root     root      4096 Sep 22 2014  ..
drwxr-xr-x 3 root     root      4096 Jul  9 12:25 backup

/home/backup:
total 12
drwxr-xr-x 3 root     root      4096 Jul  9 12:25 .
drwxr-xr-x 3 root     root      4096 Jul  9 12:25 ..
drwx------ 3 backup   sftpusers 4096 Jul  9 12:28 .ssh

/home/backup/.ssh:
total 12
drwx------ 3 backup   sftpusers 4096 Jul  9 12:28 .
drwxr-xr-x 3 root     root      4096 Jul  9 12:25 ..
-r-------- 3 backup   sftpusers 391  Jul  9 12:29 authorized_keys 

/etc/ssh/sshd_config 变为:

Match Group sftpusers
  ChrootDirectory /sftp/%u
  ForceCommand internal-sftp
  AllowTcpForwarding no
  X11Forwarding no

chroot目录结构是:

ls -laR /sftp/
/sftp/:
total 12
drwxr-xr-x  3 root root 4096 May  3 16:55 .
drwxr-xr-x 23 root root 4096 May  3 14:46 ..
drwxr-xr-x  3 root root 4096 May  3 16:45 backup

/sftp/backup:
total 12
drwxr-xr-x 3 root     root      4096 May  3 16:45 .
drwxr-xr-x 3 root     root      4096 May  3 16:55 ..
drwxr-xr-x 3 backup   sftpusers 4096 May  3 16:55 incoming
drwxr-xr-x 3 root     root      4096 May  3 16:55 home

/sftp/backup/incoming:
total 12
drwxr-xr-x 3 backup sftpusers 4096 May  3 16:55 .
drwxr-xr-x 3 root     root      4096 May  3 16:45 ..

/sftp/backup/home:
total 12
drwxr-xr-x 3 root     root      4096 May  3 16:55 .
drwxr-xr-x 3 root     root      4096 May  3 16:45 ..
drwx------ 2 backup   sftpusers 4096 May  3 21:06 backup

/sftp/backup/home/backup:
total 12
drwx------ 3 backup   sftpusers 4096 May  3 21:06 .
drwxr-xr-x 3 root     root      4096 May  3 16:55 ..

注意:/sftp/backup/home/backup 是空的，它只是提供一个看起来像非 chroot /home/backup 的路径 - - .ssh 目录是 /home/backup/.ssh 不是 /sftp/backup/home/backup/.ssh