使用pexpect和pxssh时的EOF

Question

我正在尝试使用暴力Python第2章中的Pxssh部分,通过Pexpect和暴力强制SSH密码与SSH 交互中运行代码.使用两者和我得到类似的EOF错误.child.expect()pxssh

从Python控制台运行这些命令:

import pexpect
connStr = "ssh root@127.0.0.1"
child = pexpect.spawn(connStr)
ret = child.expect([pexpect.TIMEOUT, ssh_newkey, "[P|p]assword:"])

我得到这个输出:

Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pexpect.py", li
ne 1316, in expect
    return self.expect_list(compiled_pattern_list, timeout, searchwindowsize)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pexpect.py", li
ne 1330, in expect_list
    return self.expect_loop(searcher_re(pattern_list), timeout, searchwindowsize)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pexpect.py", li
ne 1401, in expect_loop
    raise EOF (str(e) + '\n' + str(self))
EOF: End Of File (EOF) in read_nonblocking(). Empty string style platform.
<pexpect.spawn object at 0x10180c550>
version: 2.4 ($Revision: 516 $)
command: /usr/bin/ssh
args: ['/usr/bin/ssh', 'root@127.0.0.1']
searcher: searcher_re:
    0: TIMEOUT
    1: re.compile("Are you sure you want to continue connecting")
    2: re.compile("[P|p]assword:")
buffer (last 100 chars): 
before (last 100 chars): 
after: <class 'pexpect.EOF'>
match: None
match_index: None
exitstatus: 255 
flag_eof: True
pid: 12122
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

并运行这些命令,使用pxssh:

import pxssh
s = pxssh.pxssh()
s.login("127.0.0.1", "root", "1234")

我得到这个输出:

Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pxssh.py", line
 196, in login
    i = self.expect(["(?i)are you sure you want to continue connecting", original_prompt, "(?i)(?:pas
sword)|(?:passphrase for key)", "(?i)permission denied", "(?i)terminal type", TIMEOUT, "(?i)connectio
n closed by remote host"], timeout=login_timeout)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pexpect.py", li
ne 1316, in expect
    return self.expect_list(compiled_pattern_list, timeout, searchwindowsize)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pexpect.py", li
ne 1330, in expect_list
    return self.expect_loop(searcher_re(pattern_list), timeout, searchwindowsize)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pexpect.py", li
ne 1401, in expect_loop
    raise EOF (str(e) + '\n' + str(self))
EOF: End Of File (EOF) in read_nonblocking(). Empty string style platform.
<pxssh.pxssh object at 0x1016bff90>
version: 2.4 ($Revision: 516 $)
command: /usr/bin/ssh
args: ['/usr/bin/ssh', '-q', '-l', 'root', '127.0.0.1']
searcher: searcher_re:
    0: re.compile("(?i)are you sure you want to continue connecting")
    1: re.compile("[#$]")
    2: re.compile("(?i)(?:password)|(?:passphrase for key)")
    3: re.compile("(?i)permission denied")
    4: re.compile("(?i)terminal type")
    5: TIMEOUT
    6: re.compile("(?i)connection closed by remote host")
buffer (last 100 chars): 
before (last 100 chars): 
after: <class 'pexpect.EOF'>
match: None
match_index: None
exitstatus: None
flag_eof: True
pid: 12136
child_fd: 3
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

当我用其他主机替换127.0.0.1并尝试不同的用户名/密码组合时,我得到类似的结果.

所述Pexpect的文档建议使用expect(pexpect.EOF),以避免产生EOF异常.的确,当我做以下事情时:

connStr = "ssh root@127.0.0.1"
child = pexpect.spawn(connStr)
print child.expect(pexpect.EOF)

结果是0.

但仍存在以下问题:

1. 我对这本书的语法感到困惑:child.expect([pexpect.TIMEOUT, ssh_newkey, "[P|p]assword:"]).我们为什么要将列表传递给expect()？该列表应该包含什么？
2. 如何expect(pexpect.EOF)在文档中指示使用pxssh时如何使用？
3. 为什么书中的代码不能正常工作？自该书出版以来,pexpect库中有什么变化吗？是因为我在OS X上吗？

我在Mac OS X 10.8.4上运行Python 2.7和pexpect 2.4.

Answer 1

关于#2:期待EOF在这里是一个红鲱鱼.你不希望登录时看到EOF,你希望登录时提示输入密码.pxssh在从ssh登录时返回EOF而没有得到密码提示时踢出该错误.这可能发生,因为它使用ssh -q来获取警告,并且您从ssh收到警告.使用它正在使用的ssh选项并在没有q的情况下自己运行它们:

/ usr/bin/ssh -l root 127.0.0.1

在我的情况下,当ssh因为我正在连接的机器更改了其身份而导致已知的主机违规时,我可以收到此错误消息.