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remove "manhole" (ssh-accessible REPL)

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This little-used debugging feature allowed you to SSH or Telnet "into" a
Tahoe node, and get an interactive Read-Eval-Print-Loop (REPL) that
executed inside the context of the running process. The SSH
authentication code used a deprecated feature of Twisted, this code had
no unit-test coverage, and I haven't personally used it in at least 6
years (despite writing it in the first place). Time to go.

Also experiment with a Twisted-style "topfiles/" directory of NEWS
fragments. The idea is that we require all user-visible changes to
include a file or two (named as $TICKETNUM.$TYPE), and then run a script
to generate NEWS during the release process, instead of having a human
scan the commit logs and summarize the changes long after they landed.

Closes ticket:2367
This commit is contained in:
Brian Warner 2016-04-06 09:49:48 -10:00
parent a8161028d6
commit 8279d919f3
6 changed files with 6 additions and 325 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
docs/configuration.rst
View File

@ -272,19 +272,6 @@ set the ``tub.location`` option described below.
.. _`#521`: https://tahoe-lafs.org/trac/tahoe-lafs/ticket/521
``ssh.port = (strports string, optional)``
``ssh.authorized_keys_file = (filename, optional)``
This enables an SSH-based interactive Python shell, which can be used to
inspect the internal state of the node, for debugging. To cause the node
to accept SSH connections on port 8022 from the same keys as the rest of
your account, use::
[tub]
ssh.port = 8022
ssh.authorized_keys_file = ~/.ssh/authorized_keys
``tempdir = (string, optional)``
This specifies a temporary directory for the web-API server to use, for
@ -705,8 +692,6 @@ a legal one.
log_gatherer.furl = pb://soklj4y7eok5c3xkmjeqpw@192.168.69.247:44801/eqpwqtzm
timeout.keepalive = 240
timeout.disconnect = 1800
ssh.port = 8022
ssh.authorized_keys_file = ~/.ssh/authorized_keys
[client]
introducer.furl = pb://ok45ssoklj4y7eok5c3xkmj@tahoe.example:44801/ii3uumo

5
src/allmydata/debugshell.py
View File

@ -1,5 +0,0 @@
# 'app' is overwritten by manhole when the connection is established. We set
# it to None now to keep pyflakes from complaining.
app = None

279
src/allmydata/manhole.py
View File

@ -1,279 +0,0 @@
# this is adapted from my code in Buildbot -warner
import binascii, base64
from twisted.python import log
from twisted.application import service, strports
from twisted.cred import checkers, portal
from twisted.conch import manhole, telnet, manhole_ssh, checkers as conchc
from twisted.conch.insults import insults
from twisted.internet import protocol
from zope.interface import implements
from allmydata.util.fileutil import precondition_abspath
# makeTelnetProtocol and _TelnetRealm are for the TelnetManhole
class makeTelnetProtocol:
# this curries the 'portal' argument into a later call to
# TelnetTransport()
def __init__(self, portal):
self.portal = portal
def __call__(self):
auth = telnet.AuthenticatingTelnetProtocol
return telnet.TelnetTransport(auth, self.portal)
class _TelnetRealm:
implements(portal.IRealm)
def __init__(self, namespace_maker):
self.namespace_maker = namespace_maker
def requestAvatar(self, avatarId, *interfaces):
if telnet.ITelnetProtocol in interfaces:
namespace = self.namespace_maker()
p = telnet.TelnetBootstrapProtocol(insults.ServerProtocol,
manhole.ColoredManhole,
namespace)
return (telnet.ITelnetProtocol, p, lambda: None)
raise NotImplementedError()
class chainedProtocolFactory:
# this curries the 'namespace' argument into a later call to
# chainedProtocolFactory()
def __init__(self, namespace):
self.namespace = namespace
def __call__(self):
return insults.ServerProtocol(manhole.ColoredManhole, self.namespace)
class AuthorizedKeysChecker(conchc.SSHPublicKeyDatabase):
"""Accept connections using SSH keys from a given file.
SSHPublicKeyDatabase takes the username that the prospective client has
requested and attempts to get a ~/.ssh/authorized_keys file for that
username. This requires root access, so it isn't as useful as you'd
like.
Instead, this subclass looks for keys in a single file, given as an
argument. This file is typically kept in the buildmaster's basedir. The
file should have 'ssh-dss ....' lines in it, just like authorized_keys.
"""
def __init__(self, authorized_keys_file):
precondition_abspath(authorized_keys_file)
self.authorized_keys_file = authorized_keys_file
def checkKey(self, credentials):
f = open(self.authorized_keys_file)
for l in f.readlines():
l2 = l.split()
if len(l2) < 2:
continue
try:
if base64.decodestring(l2[1]) == credentials.blob:
return 1
except binascii.Error:
continue
return 0
class ModifiedColoredManhole(manhole.ColoredManhole):
def connectionMade(self):
manhole.ColoredManhole.connectionMade(self)
# look in twisted.conch.recvline.RecvLine for hints
self.keyHandlers["\x08"] = self.handle_BACKSPACE
self.keyHandlers["\x15"] = self.handle_KILLLINE
self.keyHandlers["\x01"] = self.handle_HOME
self.keyHandlers["\x04"] = self.handle_DELETE
self.keyHandlers["\x05"] = self.handle_END
self.keyHandlers["\x0b"] = self.handle_KILLLINE # really kill-to-end
#self.keyHandlers["\xe2"] = self.handle_BACKWARDS_WORD # M-b
#self.keyHandlers["\xe6"] = self.handle_FORWARDS_WORD # M-f
def handle_KILLLINE(self):
self.handle_END()
for i in range(len(self.lineBuffer)):
self.handle_BACKSPACE()
class _BaseManhole(service.MultiService):
"""This provides remote access to a python interpreter (a read/exec/print
loop) embedded in the buildmaster via an internal SSH server. This allows
detailed inspection of the buildmaster state. It is of most use to
buildbot developers. Connect to this by running an ssh client.
"""
def __init__(self, port, checker, using_ssh=True):
"""
@type port: string or int
@param port: what port should the Manhole listen on? This is a
strports specification string, like 'tcp:12345' or
'tcp:12345:interface=127.0.0.1'. Bare integers are treated as a
simple tcp port.
@type checker: an object providing the
L{twisted.cred.checkers.ICredentialsChecker} interface
@param checker: if provided, this checker is used to authenticate the
client instead of using the username/password scheme. You must either
provide a username/password or a Checker. Some useful values are::
import twisted.cred.checkers as credc
import twisted.conch.checkers as conchc
c = credc.AllowAnonymousAccess # completely open
c = credc.FilePasswordDB(passwd_filename) # file of name:passwd
c = conchc.UNIXPasswordDatabase # getpwnam() (probably /etc/passwd)
@type using_ssh: bool
@param using_ssh: If True, accept SSH connections. If False, accept
regular unencrypted telnet connections.
"""
# unfortunately, these don't work unless we're running as root
#c = credc.PluggableAuthenticationModulesChecker: PAM
#c = conchc.SSHPublicKeyDatabase() # ~/.ssh/authorized_keys
# and I can't get UNIXPasswordDatabase to work
service.MultiService.__init__(self)
if type(port) is int:
port = "tcp:%d" % port
self.port = port # for comparison later
self.checker = checker # to maybe compare later
def makeNamespace():
# close over 'self' so we can get access to .parent later
from allmydata import debugshell
debugshell.app = self.parent # make node accessible via 'app'
namespace = {}
for sym in dir(debugshell):
if sym.startswith('__') and sym.endswith('__'):
continue
namespace[sym] = getattr(debugshell, sym)
return namespace
def makeProtocol():
namespace = makeNamespace()
p = insults.ServerProtocol(ModifiedColoredManhole, namespace)
return p
self.using_ssh = using_ssh
if using_ssh:
r = manhole_ssh.TerminalRealm()
r.chainedProtocolFactory = makeProtocol
p = portal.Portal(r, [self.checker])
f = manhole_ssh.ConchFactory(p)
else:
r = _TelnetRealm(makeNamespace)
p = portal.Portal(r, [self.checker])
f = protocol.ServerFactory()
f.protocol = makeTelnetProtocol(p)
s = strports.service(self.port, f)
s.setServiceParent(self)
def startService(self):
service.MultiService.startService(self)
if self.using_ssh:
via = "via SSH"
else:
via = "via telnet"
log.msg("Manhole listening %s on port %s" % (via, self.port))
class TelnetManhole(_BaseManhole):
"""This Manhole accepts unencrypted (telnet) connections, and requires a
username and password authorize access. You are encouraged to use the
encrypted ssh-based manhole classes instead."""
def __init__(self, port, username, password):
"""
@type port: string or int
@param port: what port should the Manhole listen on? This is a
strports specification string, like 'tcp:12345' or
'tcp:12345:interface=127.0.0.1'. Bare integers are treated as a
simple tcp port.
@param username:
@param password: username= and password= form a pair of strings to
use when authenticating the remote user.
"""
self.username = username
self.password = password
c = checkers.InMemoryUsernamePasswordDatabaseDontUse()
c.addUser(username, password)
_BaseManhole.__init__(self, port, c, using_ssh=False)
class PasswordManhole(_BaseManhole):
"""This Manhole accepts encrypted (ssh) connections, and requires a
username and password to authorize access.
"""
def __init__(self, port, username, password):
"""
@type port: string or int
@param port: what port should the Manhole listen on? This is a
strports specification string, like 'tcp:12345' or
'tcp:12345:interface=127.0.0.1'. Bare integers are treated as a
simple tcp port.
@param username:
@param password: username= and password= form a pair of strings to
use when authenticating the remote user.
"""
self.username = username
self.password = password
c = checkers.InMemoryUsernamePasswordDatabaseDontUse()
c.addUser(username, password)
_BaseManhole.__init__(self, port, c)
class AuthorizedKeysManhole(_BaseManhole):
"""This Manhole accepts ssh connections, and requires that the
prospective client have an ssh private key that matches one of the public
keys in our authorized_keys file. It is created with the name of a file
that contains the public keys that we will accept."""
def __init__(self, port, keyfile):
"""
@type port: string or int
@param port: what port should the Manhole listen on? This is a
strports specification string, like 'tcp:12345' or
'tcp:12345:interface=127.0.0.1'. Bare integers are treated as a
simple tcp port.
@param keyfile: the path of a file that contains SSH public keys of
authorized users, one per line. This is the exact
same format as used by sshd in ~/.ssh/authorized_keys .
The path should be absolute.
"""
self.keyfile = keyfile
c = AuthorizedKeysChecker(keyfile)
_BaseManhole.__init__(self, port, c)
class ArbitraryCheckerManhole(_BaseManhole):
"""This Manhole accepts ssh connections, but uses an arbitrary
user-supplied 'checker' object to perform authentication."""
def __init__(self, port, checker):
"""
@type port: string or int
@param port: what port should the Manhole listen on? This is a
strports specification string, like 'tcp:12345' or
'tcp:12345:interface=127.0.0.1'. Bare integers are treated as a
simple tcp port.
@param checker: an instance of a twisted.cred 'checker' which will
perform authentication
"""
_BaseManhole.__init__(self, port, checker)

11
src/allmydata/node.py
View File

@ -88,7 +88,6 @@ class Node(service.MultiService):
self.create_tub()
self.logSource="Node"
self.setup_ssh()
self.setup_logging()
self.log("Node constructed. " + get_package_versions_string())
iputil.increase_rlimits()
@ -203,16 +202,6 @@ class Node(service.MultiService):
# any services with the Tub until after that point
self.tub.setServiceParent(self)
def setup_ssh(self):
ssh_port = self.get_config("node", "ssh.port", "")
if ssh_port:
ssh_keyfile_config = self.get_config("node", "ssh.authorized_keys_file").decode('utf-8')
ssh_keyfile = abspath_expanduser_unicode(ssh_keyfile_config, base=self.basedir)
from allmydata import manhole
m = manhole.AuthorizedKeysManhole(ssh_port, ssh_keyfile)
m.setServiceParent(self)
self.log("AuthorizedKeysManhole listening on %s" % (ssh_port,))
def get_app_versions(self):
# TODO: merge this with allmydata.get_package_versions
return dict(app_versions.versions)

15
src/allmydata/test/test_client.py
View File

@ -11,7 +11,6 @@ from allmydata.node import Node, OldConfigError, OldConfigOptionError, MissingCo
from allmydata.frontends.auth import NeedRootcapLookupScheme
from allmydata import client
from allmydata.storage_client import StorageFarmBroker
from allmydata.manhole import AuthorizedKeysManhole
from allmydata.util import base32, fileutil
from allmydata.interfaces import IFilesystemNode, IFileNode, \
IImmutableFileNode, IMutableFileNode, IDirectoryNode
@ -195,20 +194,6 @@ class Basic(testutil.ReallyEqualMixin, unittest.TestCase):
expected = fileutil.abspath_expanduser_unicode(u"relative", abs_basedir)
self.failUnlessReallyEqual(w.staticdir, expected)
def test_manhole_keyfile(self):
basedir = u"client.Basic.test_manhole_keyfile"
os.mkdir(basedir)
fileutil.write(os.path.join(basedir, "tahoe.cfg"),
BASECONFIG +
"[node]\n" +
"ssh.port = tcp:0:interface=127.0.0.1\n" +
"ssh.authorized_keys_file = relative\n")
c = client.Client(basedir)
m = [s for s in c if isinstance(s, AuthorizedKeysManhole)][0]
abs_basedir = fileutil.abspath_expanduser_unicode(basedir)
expected = fileutil.abspath_expanduser_unicode(u"relative", abs_basedir)
self.failUnlessReallyEqual(m.keyfile, expected)
# TODO: also test config options for SFTP.
def test_ftp_auth_keyfile(self):

6
topfiles/2367.removal Normal file
View File

@ -0,0 +1,6 @@
The little-used "manhole" debugging feature has been removed. This allowed
you to SSH or Telnet "into" a Tahoe node, providing an interactive
Read-Eval-Print-Loop (REPL) that executed inside the context of the running
process. The SSH authentication code used a deprecated feature of Twisted,
this code had no unit-test coverage, and I haven't personally used it in at
least 6 years (despite writing it in the first place). Time to go.