pexpect和ssh：如何格式化su - root -c后的命令字符串

Question

我正在尝试遍历一组服务器和密码，以便更改这些服务器上的sshd配置，这样我就可以通过无密码的SSH密钥以root身份登录和运行命令。

我在bash中可以很容易做到这一点，但我想学习Python，并且（显然）希望避免手动输入密码。

这是我想在bash中做的事情：

scp ~/.ssh/id_rsa.pub /etc/ssh/sshd_config USER@IP:/tmp/

ssh -o StrictHostKeyChecking=no -t USER@IP "su - root -c \"chown root:root /tmp/id_rsa.pub; chmod 600 /tmp/id_rsa.pub; chown root:root /tmp/sshd_config; mkdir /root/.ssh; chown root:root /root/.ssh; chmod 700 /root/.ssh; mv /tmp/id_rsa.pub /root/.ssh/authorized_keys; mv /tmp/sshd_config /etc/ssh/; service sshd reload\""

我在Python中用pexpect接近实现这个目标：

import pexpect

USER="user"
HOST="192.168.1.1"
USERPASS="userpass" 
ROOTPASS="rootpass"

COMMAND1="scp /Users/user/.ssh/id_rsa.pub /Users/user/github/ssh-pexpect/sshd_config %s@%s:/tmp/" % (USER, HOST)

COMMAND2="ssh -o StrictHostKeyChecking=no -t %s@%s \"su - root -c \"chown root:root /tmp/id_rsa.pub; chmod 600 /tmp/id_rsa.pub; chown root:root /tmp/sshd_config; mkdir /root/.ssh; chown root:root /root/.ssh; chmod 700 /root/.ssh; mv /tmp/id_rsa.pub /root/.ssh/authorized_keys; mv /tmp/sshd_config /etc/ssh/; service sshd reload\"\"" % (USER, HOST)

child = pexpect.spawn(COMMAND1)
child.expect('password:')
child.sendline(USERPASS)
child.expect(pexpect.EOF)
print child.before

child = pexpect.spawn(COMMAND2)
child.expect('password:')
child.sendline(USERPASS)
child.expect('Password:')
child.sendline(ROOTPASS)
child.expect(pexpect.EOF)
print child.before

当我运行那个COMMAND1（scp命令）时，一切正常。但是COMMAND2却失败了：

server1:ssh-pexpect user$ python test4.py 

id_rsa.pub                                    100%  410     0.4KB/s   00:00    
sshd_config                                   100% 3498     3.4KB/s   00:00    

Traceback (most recent call last):
  File "test4.py", line 25, in <module>
    child.expect(pexpect.EOF)
  File "/Library/Python/2.7/site-packages/pexpect.py", line 1316, in expect
    return self.expect_list(compiled_pattern_list, timeout, searchwindowsize)
  File "/Library/Python/2.7/site-packages/pexpect.py", line 1330, in expect_list
    return self.expect_loop(searcher_re(pattern_list), timeout, searchwindowsize)
  File "/Library/Python/2.7/site-packages/pexpect.py", line 1414, in expect_loop
    raise TIMEOUT (str(e) + '\n' + str(self))
pexpect.TIMEOUT: Timeout exceeded in read_nonblocking().
<pexpect.spawn object at 0x102b796d0>
version: 2.4 ($Revision: 516 $)
command: /usr/bin/ssh
args: ['/usr/bin/ssh', '-o', 'StrictHostKeyChecking=no', '-t', 'user@192.168.1.1', 'su - root -c chown', 'root:root', '/tmp/id_rsa.pub;', 'chmod', '600', '/tmp/id_rsa.pub;', 'chown', 'root:root', '/tmp/sshd_config;', 'mkdir', '/root/.ssh;', 'chown', 'root:root', '/root/.ssh;', 'chmod', '700', '/root/.ssh;', 'mv', '/tmp/id_rsa.pub', '/root/.ssh/authorized_keys;', 'mv', '/tmp/sshd_config', '/etc/ssh/;', 'service', 'sshd', 'reload']
searcher: searcher_re:
    0: EOF
buffer (last 100 chars): : Permission denied
mv: try to overwrite `/etc/ssh/sshd_config', overriding mode 0600 (rw-------)? 
before (last 100 chars): : Permission denied
mv: try to overwrite `/etc/ssh/sshd_config', overriding mode 0600 (rw-------)? 
after: <class 'pexpect.TIMEOUT'>
match: None
match_index: None
exitstatus: None
flag_eof: False
pid: 3612
child_fd: 4
closed: False
timeout: 30
delimiter: <class 'pexpect.EOF'>
logfile: None
logfile_read: None
logfile_send: None
maxread: 2000
ignorecase: False
searchwindowsize: None
delaybeforesend: 0.05
delayafterclose: 0.1
delayafterterminate: 0.1

如果我在运行脚本之前删除远程服务器上的/etc/ssh/sshd_config文件，我会得到：

server1:ssh-pexpect user$ python test4.py  
id_rsa.pub                                    100%  410     0.4KB/s   00:00    
sshd_config                                   100% 3498     3.4KB/s   00:00    


chown: missing operand
Try `chown --help' for more information.
chown: changing ownership of `/tmp/sshd_config': Operation not permitted
mkdir: cannot create directory `/root/.ssh': Permission denied
chown: cannot access `/root/.ssh': Permission denied
chmod: cannot access `/root/.ssh': Permission denied
mv: accessing `/root/.ssh/authorized_keys': Permission denied
mv: cannot move `/tmp/sshd_config' to `/etc/ssh/sshd_config': Permission denied
bash: service: command not found
Connection to 192.168.1.1 closed.

我甚至不知道该如何调试这个问题，看看哪里出错了。我觉得COMMAND2的解析可能有问题。我对Python还很陌生，所以任何建议都很感激。谢谢。

ssh 远程服务器 bash脚本调试技巧 pexpect 无密码登录 sshd配置命令字符串

pexpect和ssh：如何格式化su - root -c后的命令字符串

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