root / lib / ssh.py @ bfbffd55
History | View | Annotate | Download (10.2 kB)
1 |
#
|
---|---|
2 |
#
|
3 |
|
4 |
# Copyright (C) 2006, 2007, 2010, 2011 Google Inc.
|
5 |
#
|
6 |
# This program is free software; you can redistribute it and/or modify
|
7 |
# it under the terms of the GNU General Public License as published by
|
8 |
# the Free Software Foundation; either version 2 of the License, or
|
9 |
# (at your option) any later version.
|
10 |
#
|
11 |
# This program is distributed in the hope that it will be useful, but
|
12 |
# WITHOUT ANY WARRANTY; without even the implied warranty of
|
13 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
14 |
# General Public License for more details.
|
15 |
#
|
16 |
# You should have received a copy of the GNU General Public License
|
17 |
# along with this program; if not, write to the Free Software
|
18 |
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
19 |
# 02110-1301, USA.
|
20 |
|
21 |
|
22 |
"""Module encapsulating ssh functionality.
|
23 |
|
24 |
"""
|
25 |
|
26 |
|
27 |
import os |
28 |
import logging |
29 |
|
30 |
from ganeti import utils |
31 |
from ganeti import errors |
32 |
from ganeti import constants |
33 |
from ganeti import netutils |
34 |
from ganeti import pathutils |
35 |
from ganeti import vcluster |
36 |
from ganeti import compat |
37 |
|
38 |
|
39 |
def GetUserFiles(user, mkdir=False, dircheck=True, kind=constants.SSHK_DSA, |
40 |
_homedir_fn=None):
|
41 |
"""Return the paths of a user's SSH files.
|
42 |
|
43 |
@type user: string
|
44 |
@param user: Username
|
45 |
@type mkdir: bool
|
46 |
@param mkdir: Whether to create ".ssh" directory if it doesn't exist
|
47 |
@type dircheck: bool
|
48 |
@param dircheck: Whether to check if ".ssh" directory exists
|
49 |
@type kind: string
|
50 |
@param kind: One of L{constants.SSHK_ALL}
|
51 |
@rtype: tuple; (string, string, string)
|
52 |
@return: Tuple containing three file system paths; the private SSH key file,
|
53 |
the public SSH key file and the user's C{authorized_keys} file
|
54 |
@raise errors.OpExecError: When home directory of the user can not be
|
55 |
determined
|
56 |
@raise errors.OpExecError: Regardless of the C{mkdir} parameters, this
|
57 |
exception is raised if C{~$user/.ssh} is not a directory and C{dircheck}
|
58 |
is set to C{True}
|
59 |
|
60 |
"""
|
61 |
if _homedir_fn is None: |
62 |
_homedir_fn = utils.GetHomeDir |
63 |
|
64 |
user_dir = _homedir_fn(user) |
65 |
if not user_dir: |
66 |
raise errors.OpExecError("Cannot resolve home of user '%s'" % user) |
67 |
|
68 |
if kind == constants.SSHK_DSA:
|
69 |
suffix = "dsa"
|
70 |
elif kind == constants.SSHK_RSA:
|
71 |
suffix = "rsa"
|
72 |
else:
|
73 |
raise errors.ProgrammerError("Unknown SSH key kind '%s'" % kind) |
74 |
|
75 |
ssh_dir = utils.PathJoin(user_dir, ".ssh")
|
76 |
if mkdir:
|
77 |
utils.EnsureDirs([(ssh_dir, constants.SECURE_DIR_MODE)]) |
78 |
elif dircheck and not os.path.isdir(ssh_dir): |
79 |
raise errors.OpExecError("Path %s is not a directory" % ssh_dir) |
80 |
|
81 |
return [utils.PathJoin(ssh_dir, base)
|
82 |
for base in ["id_%s" % suffix, "id_%s.pub" % suffix, |
83 |
"authorized_keys"]]
|
84 |
|
85 |
|
86 |
def GetAllUserFiles(user, mkdir=False, dircheck=True, _homedir_fn=None): |
87 |
"""Wrapper over L{GetUserFiles} to retrieve files for all SSH key types.
|
88 |
|
89 |
See L{GetUserFiles} for details.
|
90 |
|
91 |
@rtype: tuple; (string, dict with string as key, tuple of (string, string) as
|
92 |
value)
|
93 |
|
94 |
"""
|
95 |
helper = compat.partial(GetUserFiles, user, mkdir=mkdir, dircheck=dircheck, |
96 |
_homedir_fn=_homedir_fn) |
97 |
result = [(kind, helper(kind=kind)) for kind in constants.SSHK_ALL] |
98 |
|
99 |
authorized_keys = [i for (_, (_, _, i)) in result] |
100 |
|
101 |
assert len(frozenset(authorized_keys)) == 1, \ |
102 |
"Different paths for authorized_keys were returned"
|
103 |
|
104 |
return (authorized_keys[0], |
105 |
dict((kind, (privkey, pubkey))
|
106 |
for (kind, (privkey, pubkey, _)) in result)) |
107 |
|
108 |
|
109 |
class SshRunner: |
110 |
"""Wrapper for SSH commands.
|
111 |
|
112 |
"""
|
113 |
def __init__(self, cluster_name, ipv6=False): |
114 |
"""Initializes this class.
|
115 |
|
116 |
@type cluster_name: str
|
117 |
@param cluster_name: name of the cluster
|
118 |
@type ipv6: bool
|
119 |
@param ipv6: If true, force ssh to use IPv6 addresses only
|
120 |
|
121 |
"""
|
122 |
self.cluster_name = cluster_name
|
123 |
self.ipv6 = ipv6
|
124 |
|
125 |
def _BuildSshOptions(self, batch, ask_key, use_cluster_key, |
126 |
strict_host_check, private_key=None, quiet=True): |
127 |
"""Builds a list with needed SSH options.
|
128 |
|
129 |
@param batch: same as ssh's batch option
|
130 |
@param ask_key: allows ssh to ask for key confirmation; this
|
131 |
parameter conflicts with the batch one
|
132 |
@param use_cluster_key: if True, use the cluster name as the
|
133 |
HostKeyAlias name
|
134 |
@param strict_host_check: this makes the host key checking strict
|
135 |
@param private_key: use this private key instead of the default
|
136 |
@param quiet: whether to enable -q to ssh
|
137 |
|
138 |
@rtype: list
|
139 |
@return: the list of options ready to use in L{utils.process.RunCmd}
|
140 |
|
141 |
"""
|
142 |
options = [ |
143 |
"-oEscapeChar=none",
|
144 |
"-oHashKnownHosts=no",
|
145 |
"-oGlobalKnownHostsFile=%s" % pathutils.SSH_KNOWN_HOSTS_FILE,
|
146 |
"-oUserKnownHostsFile=/dev/null",
|
147 |
"-oCheckHostIp=no",
|
148 |
] |
149 |
|
150 |
if use_cluster_key:
|
151 |
options.append("-oHostKeyAlias=%s" % self.cluster_name) |
152 |
|
153 |
if quiet:
|
154 |
options.append("-q")
|
155 |
|
156 |
if private_key:
|
157 |
options.append("-i%s" % private_key)
|
158 |
|
159 |
# TODO: Too many boolean options, maybe convert them to more descriptive
|
160 |
# constants.
|
161 |
|
162 |
# Note: ask_key conflicts with batch mode
|
163 |
if batch:
|
164 |
if ask_key:
|
165 |
raise errors.ProgrammerError("SSH call requested conflicting options") |
166 |
|
167 |
options.append("-oBatchMode=yes")
|
168 |
|
169 |
if strict_host_check:
|
170 |
options.append("-oStrictHostKeyChecking=yes")
|
171 |
else:
|
172 |
options.append("-oStrictHostKeyChecking=no")
|
173 |
|
174 |
else:
|
175 |
# non-batch mode
|
176 |
|
177 |
if ask_key:
|
178 |
options.append("-oStrictHostKeyChecking=ask")
|
179 |
elif strict_host_check:
|
180 |
options.append("-oStrictHostKeyChecking=yes")
|
181 |
else:
|
182 |
options.append("-oStrictHostKeyChecking=no")
|
183 |
|
184 |
if self.ipv6: |
185 |
options.append("-6")
|
186 |
|
187 |
return options
|
188 |
|
189 |
def BuildCmd(self, hostname, user, command, batch=True, ask_key=False, |
190 |
tty=False, use_cluster_key=True, strict_host_check=True, |
191 |
private_key=None, quiet=True): |
192 |
"""Build an ssh command to execute a command on a remote node.
|
193 |
|
194 |
@param hostname: the target host, string
|
195 |
@param user: user to auth as
|
196 |
@param command: the command
|
197 |
@param batch: if true, ssh will run in batch mode with no prompting
|
198 |
@param ask_key: if true, ssh will run with
|
199 |
StrictHostKeyChecking=ask, so that we can connect to an
|
200 |
unknown host (not valid in batch mode)
|
201 |
@param use_cluster_key: whether to expect and use the
|
202 |
cluster-global SSH key
|
203 |
@param strict_host_check: whether to check the host's SSH key at all
|
204 |
@param private_key: use this private key instead of the default
|
205 |
@param quiet: whether to enable -q to ssh
|
206 |
|
207 |
@return: the ssh call to run 'command' on the remote host.
|
208 |
|
209 |
"""
|
210 |
argv = [constants.SSH] |
211 |
argv.extend(self._BuildSshOptions(batch, ask_key, use_cluster_key,
|
212 |
strict_host_check, private_key, |
213 |
quiet=quiet)) |
214 |
if tty:
|
215 |
argv.extend(["-t", "-t"]) |
216 |
|
217 |
argv.append("%s@%s" % (user, hostname))
|
218 |
|
219 |
# Insert variables for virtual nodes
|
220 |
argv.extend("export %s=%s;" %
|
221 |
(utils.ShellQuote(name), utils.ShellQuote(value)) |
222 |
for (name, value) in |
223 |
vcluster.EnvironmentForHost(hostname).items()) |
224 |
|
225 |
argv.append(command) |
226 |
|
227 |
return argv
|
228 |
|
229 |
def Run(self, *args, **kwargs): |
230 |
"""Runs a command on a remote node.
|
231 |
|
232 |
This method has the same return value as `utils.RunCmd()`, which it
|
233 |
uses to launch ssh.
|
234 |
|
235 |
Args: see SshRunner.BuildCmd.
|
236 |
|
237 |
@rtype: L{utils.process.RunResult}
|
238 |
@return: the result as from L{utils.process.RunCmd()}
|
239 |
|
240 |
"""
|
241 |
return utils.RunCmd(self.BuildCmd(*args, **kwargs)) |
242 |
|
243 |
def CopyFileToNode(self, node, filename): |
244 |
"""Copy a file to another node with scp.
|
245 |
|
246 |
@param node: node in the cluster
|
247 |
@param filename: absolute pathname of a local file
|
248 |
|
249 |
@rtype: boolean
|
250 |
@return: the success of the operation
|
251 |
|
252 |
"""
|
253 |
if not os.path.isabs(filename): |
254 |
logging.error("File %s must be an absolute path", filename)
|
255 |
return False |
256 |
|
257 |
if not os.path.isfile(filename): |
258 |
logging.error("File %s does not exist", filename)
|
259 |
return False |
260 |
|
261 |
command = [constants.SCP, "-p"]
|
262 |
command.extend(self._BuildSshOptions(True, False, True, True)) |
263 |
command.append(filename) |
264 |
if netutils.IP6Address.IsValid(node):
|
265 |
node = netutils.FormatAddress((node, None))
|
266 |
|
267 |
command.append("%s:%s" % (node, vcluster.ExchangeNodeRoot(node, filename)))
|
268 |
|
269 |
result = utils.RunCmd(command) |
270 |
|
271 |
if result.failed:
|
272 |
logging.error("Copy to node %s failed (%s) error '%s',"
|
273 |
" command was '%s'",
|
274 |
node, result.fail_reason, result.output, result.cmd) |
275 |
|
276 |
return not result.failed |
277 |
|
278 |
def VerifyNodeHostname(self, node): |
279 |
"""Verify hostname consistency via SSH.
|
280 |
|
281 |
This functions connects via ssh to a node and compares the hostname
|
282 |
reported by the node to the name with have (the one that we
|
283 |
connected to).
|
284 |
|
285 |
This is used to detect problems in ssh known_hosts files
|
286 |
(conflicting known hosts) and inconsistencies between dns/hosts
|
287 |
entries and local machine names
|
288 |
|
289 |
@param node: nodename of a host to check; can be short or
|
290 |
full qualified hostname
|
291 |
|
292 |
@return: (success, detail), where:
|
293 |
- success: True/False
|
294 |
- detail: string with details
|
295 |
|
296 |
"""
|
297 |
cmd = ("if test -z \"$GANETI_HOSTNAME\"; then"
|
298 |
" hostname --fqdn;"
|
299 |
"else"
|
300 |
" echo \"$GANETI_HOSTNAME\";"
|
301 |
"fi")
|
302 |
retval = self.Run(node, constants.SSH_LOGIN_USER, cmd, quiet=False) |
303 |
|
304 |
if retval.failed:
|
305 |
msg = "ssh problem"
|
306 |
output = retval.output |
307 |
if output:
|
308 |
msg += ": %s" % output
|
309 |
else:
|
310 |
msg += ": %s (no output)" % retval.fail_reason
|
311 |
logging.error("Command %s failed: %s", retval.cmd, msg)
|
312 |
return False, msg |
313 |
|
314 |
remotehostname = retval.stdout.strip() |
315 |
|
316 |
if not remotehostname or remotehostname != node: |
317 |
if node.startswith(remotehostname + "."): |
318 |
msg = "hostname not FQDN"
|
319 |
else:
|
320 |
msg = "hostname mismatch"
|
321 |
return False, ("%s: expected %s but got %s" % |
322 |
(msg, node, remotehostname)) |
323 |
|
324 |
return True, "host matches" |
325 |
|
326 |
|
327 |
def WriteKnownHostsFile(cfg, file_name): |
328 |
"""Writes the cluster-wide equally known_hosts file.
|
329 |
|
330 |
"""
|
331 |
utils.WriteFile(file_name, mode=0600,
|
332 |
data="%s ssh-rsa %s\n" % (cfg.GetClusterName(),
|
333 |
cfg.GetHostKey())) |