Current File : //proc/self/root/usr/lib/python3/dist-packages/twisted/conch/test/test_userauth.py
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Tests for the implementation of the ssh-userauth service.

Maintainer: Paul Swartz
"""

from types import ModuleType
from typing import Optional

from zope.interface import implementer

from twisted.conch.error import ConchError, ValidPublicKey
from twisted.cred.checkers import ICredentialsChecker
from twisted.cred.credentials import IAnonymous, ISSHPrivateKey, IUsernamePassword
from twisted.cred.error import UnauthorizedLogin
from twisted.cred.portal import IRealm, Portal
from twisted.internet import defer, task
from twisted.protocols import loopback
from twisted.python.reflect import requireModule
from twisted.trial import unittest

keys: Optional[ModuleType] = None
if requireModule("cryptography"):
    from twisted.conch.checkers import SSHProtocolChecker
    from twisted.conch.ssh import keys, transport, userauth
    from twisted.conch.ssh.common import NS
    from twisted.conch.test import keydata
else:

    class transport:  # type: ignore[no-redef]
        class SSHTransportBase:
            """
            A stub class so that later class definitions won't die.
            """

    class userauth:  # type: ignore[no-redef]
        class SSHUserAuthClient:
            """
            A stub class so that later class definitions won't die.
            """


class ClientUserAuth(userauth.SSHUserAuthClient):
    """
    A mock user auth client.
    """

    def getPublicKey(self):
        """
        If this is the first time we've been called, return a blob for
        the DSA key.  Otherwise, return a blob
        for the RSA key.
        """
        if self.lastPublicKey:
            return keys.Key.fromString(keydata.publicRSA_openssh)
        else:
            return defer.succeed(keys.Key.fromString(keydata.publicDSA_openssh))

    def getPrivateKey(self):
        """
        Return the private key object for the RSA key.
        """
        return defer.succeed(keys.Key.fromString(keydata.privateRSA_openssh))

    def getPassword(self, prompt=None):
        """
        Return 'foo' as the password.
        """
        return defer.succeed(b"foo")

    def getGenericAnswers(self, name, information, answers):
        """
        Return 'foo' as the answer to two questions.
        """
        return defer.succeed(("foo", "foo"))


class OldClientAuth(userauth.SSHUserAuthClient):
    """
    The old SSHUserAuthClient returned a cryptography key object from
    getPrivateKey() and a string from getPublicKey
    """

    def getPrivateKey(self):
        return defer.succeed(keys.Key.fromString(keydata.privateRSA_openssh).keyObject)

    def getPublicKey(self):
        return keys.Key.fromString(keydata.publicRSA_openssh).blob()


class ClientAuthWithoutPrivateKey(userauth.SSHUserAuthClient):
    """
    This client doesn't have a private key, but it does have a public key.
    """

    def getPrivateKey(self):
        return

    def getPublicKey(self):
        return keys.Key.fromString(keydata.publicRSA_openssh)


class FakeTransport(transport.SSHTransportBase):
    """
    L{userauth.SSHUserAuthServer} expects an SSH transport which has a factory
    attribute which has a portal attribute. Because the portal is important for
    testing authentication, we need to be able to provide an interesting portal
    object to the L{SSHUserAuthServer}.

    In addition, we want to be able to capture any packets sent over the
    transport.

    @ivar packets: a list of 2-tuples: (messageType, data).  Each 2-tuple is
        a sent packet.
    @type packets: C{list}
    @param lostConnecion: True if loseConnection has been called on us.
    @type lostConnection: L{bool}
    """

    class Service:
        """
        A mock service, representing the other service offered by the server.
        """

        name = b"nancy"

        def serviceStarted(self):
            pass

    class Factory:
        """
        A mock factory, representing the factory that spawned this user auth
        service.
        """

        def getService(self, transport, service):
            """
            Return our fake service.
            """
            if service == b"none":
                return FakeTransport.Service

    def __init__(self, portal):
        self.factory = self.Factory()
        self.factory.portal = portal
        self.lostConnection = False
        self.transport = self
        self.packets = []

    def sendPacket(self, messageType, message):
        """
        Record the packet sent by the service.
        """
        self.packets.append((messageType, message))

    def isEncrypted(self, direction):
        """
        Pretend that this transport encrypts traffic in both directions. The
        SSHUserAuthServer disables password authentication if the transport
        isn't encrypted.
        """
        return True

    def loseConnection(self):
        self.lostConnection = True


@implementer(IRealm)
class Realm:
    """
    A mock realm for testing L{userauth.SSHUserAuthServer}.

    This realm is not actually used in the course of testing, so it returns the
    simplest thing that could possibly work.
    """

    def requestAvatar(self, avatarId, mind, *interfaces):
        return defer.succeed((interfaces[0], None, lambda: None))


@implementer(ICredentialsChecker)
class PasswordChecker:
    """
    A very simple username/password checker which authenticates anyone whose
    password matches their username and rejects all others.
    """

    credentialInterfaces = (IUsernamePassword,)

    def requestAvatarId(self, creds):
        if creds.username == creds.password:
            return defer.succeed(creds.username)
        return defer.fail(UnauthorizedLogin("Invalid username/password pair"))


@implementer(ICredentialsChecker)
class PrivateKeyChecker:
    """
    A very simple public key checker which authenticates anyone whose
    public/private keypair is the same keydata.public/privateRSA_openssh.
    """

    credentialInterfaces = (ISSHPrivateKey,)

    def requestAvatarId(self, creds):
        if creds.blob == keys.Key.fromString(keydata.publicRSA_openssh).blob():
            if creds.signature is not None:
                obj = keys.Key.fromString(creds.blob)
                if obj.verify(creds.signature, creds.sigData):
                    return creds.username
            else:
                raise ValidPublicKey()
        raise UnauthorizedLogin()


@implementer(ICredentialsChecker)
class AnonymousChecker:
    """
    A simple checker which isn't supported by L{SSHUserAuthServer}.
    """

    credentialInterfaces = (IAnonymous,)

    def requestAvatarId(self, credentials):
        # ICredentialsChecker.requestAvatarId
        pass


class SSHUserAuthServerTests(unittest.TestCase):
    """
    Tests for SSHUserAuthServer.
    """

    if keys is None:
        skip = "cannot run without cryptography"

    def setUp(self):
        self.realm = Realm()
        self.portal = Portal(self.realm)
        self.portal.registerChecker(PasswordChecker())
        self.portal.registerChecker(PrivateKeyChecker())
        self.authServer = userauth.SSHUserAuthServer()
        self.authServer.transport = FakeTransport(self.portal)
        self.authServer.serviceStarted()
        self.authServer.supportedAuthentications.sort()  # give a consistent
        # order

    def tearDown(self):
        self.authServer.serviceStopped()
        self.authServer = None

    def _checkFailed(self, ignored):
        """
        Check that the authentication has failed.
        """
        self.assertEqual(
            self.authServer.transport.packets[-1],
            (userauth.MSG_USERAUTH_FAILURE, NS(b"password,publickey") + b"\x00"),
        )

    def test_noneAuthentication(self):
        """
        A client may request a list of authentication 'method name' values
        that may continue by using the "none" authentication 'method name'.

        See RFC 4252 Section 5.2.
        """
        d = self.authServer.ssh_USERAUTH_REQUEST(
            NS(b"foo") + NS(b"service") + NS(b"none")
        )
        return d.addCallback(self._checkFailed)

    def test_successfulPasswordAuthentication(self):
        """
        When provided with correct password authentication information, the
        server should respond by sending a MSG_USERAUTH_SUCCESS message with
        no other data.

        See RFC 4252, Section 5.1.
        """
        packet = b"".join([NS(b"foo"), NS(b"none"), NS(b"password"), b"\0", NS(b"foo")])
        d = self.authServer.ssh_USERAUTH_REQUEST(packet)

        def check(ignored):
            self.assertEqual(
                self.authServer.transport.packets,
                [(userauth.MSG_USERAUTH_SUCCESS, b"")],
            )

        return d.addCallback(check)

    def test_failedPasswordAuthentication(self):
        """
        When provided with invalid authentication details, the server should
        respond by sending a MSG_USERAUTH_FAILURE message which states whether
        the authentication was partially successful, and provides other, open
        options for authentication.

        See RFC 4252, Section 5.1.
        """
        # packet = username, next_service, authentication type, FALSE, password
        packet = b"".join([NS(b"foo"), NS(b"none"), NS(b"password"), b"\0", NS(b"bar")])
        self.authServer.clock = task.Clock()
        d = self.authServer.ssh_USERAUTH_REQUEST(packet)
        self.assertEqual(self.authServer.transport.packets, [])
        self.authServer.clock.advance(2)
        return d.addCallback(self._checkFailed)

    def test_successfulPrivateKeyAuthentication(self):
        """
        Test that private key authentication completes successfully,
        """
        blob = keys.Key.fromString(keydata.publicRSA_openssh).blob()
        obj = keys.Key.fromString(keydata.privateRSA_openssh)
        packet = (
            NS(b"foo")
            + NS(b"none")
            + NS(b"publickey")
            + b"\xff"
            + NS(obj.sshType())
            + NS(blob)
        )
        self.authServer.transport.sessionID = b"test"
        signature = obj.sign(
            NS(b"test") + bytes((userauth.MSG_USERAUTH_REQUEST,)) + packet
        )
        packet += NS(signature)
        d = self.authServer.ssh_USERAUTH_REQUEST(packet)

        def check(ignored):
            self.assertEqual(
                self.authServer.transport.packets,
                [(userauth.MSG_USERAUTH_SUCCESS, b"")],
            )

        return d.addCallback(check)

    def test_requestRaisesConchError(self):
        """
        ssh_USERAUTH_REQUEST should raise a ConchError if tryAuth returns
        None. Added to catch a bug noticed by pyflakes.
        """
        d = defer.Deferred()

        def mockCbFinishedAuth(self, ignored):
            self.fail("request should have raised ConochError")

        def mockTryAuth(kind, user, data):
            return None

        def mockEbBadAuth(reason):
            d.errback(reason.value)

        self.patch(self.authServer, "tryAuth", mockTryAuth)
        self.patch(self.authServer, "_cbFinishedAuth", mockCbFinishedAuth)
        self.patch(self.authServer, "_ebBadAuth", mockEbBadAuth)

        packet = NS(b"user") + NS(b"none") + NS(b"public-key") + NS(b"data")
        # If an error other than ConchError is raised, this will trigger an
        # exception.
        self.authServer.ssh_USERAUTH_REQUEST(packet)
        return self.assertFailure(d, ConchError)

    def test_verifyValidPrivateKey(self):
        """
        Test that verifying a valid private key works.
        """
        blob = keys.Key.fromString(keydata.publicRSA_openssh).blob()
        packet = (
            NS(b"foo")
            + NS(b"none")
            + NS(b"publickey")
            + b"\x00"
            + NS(b"ssh-rsa")
            + NS(blob)
        )
        d = self.authServer.ssh_USERAUTH_REQUEST(packet)

        def check(ignored):
            self.assertEqual(
                self.authServer.transport.packets,
                [(userauth.MSG_USERAUTH_PK_OK, NS(b"ssh-rsa") + NS(blob))],
            )

        return d.addCallback(check)

    def test_failedPrivateKeyAuthenticationWithoutSignature(self):
        """
        Test that private key authentication fails when the public key
        is invalid.
        """
        blob = keys.Key.fromString(keydata.publicDSA_openssh).blob()
        packet = (
            NS(b"foo")
            + NS(b"none")
            + NS(b"publickey")
            + b"\x00"
            + NS(b"ssh-dsa")
            + NS(blob)
        )
        d = self.authServer.ssh_USERAUTH_REQUEST(packet)
        return d.addCallback(self._checkFailed)

    def test_failedPrivateKeyAuthenticationWithSignature(self):
        """
        Test that private key authentication fails when the public key
        is invalid.
        """
        blob = keys.Key.fromString(keydata.publicRSA_openssh).blob()
        obj = keys.Key.fromString(keydata.privateRSA_openssh)
        packet = (
            NS(b"foo")
            + NS(b"none")
            + NS(b"publickey")
            + b"\xff"
            + NS(b"ssh-rsa")
            + NS(blob)
            + NS(obj.sign(blob))
        )
        self.authServer.transport.sessionID = b"test"
        d = self.authServer.ssh_USERAUTH_REQUEST(packet)
        return d.addCallback(self._checkFailed)

    def test_unsupported_publickey(self):
        """
        Private key authentication fails when the public key type is
        unsupported or the public key is corrupt.
        """
        blob = keys.Key.fromString(keydata.publicDSA_openssh).blob()

        # Change the blob to a bad type
        blob = NS(b"ssh-bad-type") + blob[11:]

        packet = (
            NS(b"foo")
            + NS(b"none")
            + NS(b"publickey")
            + b"\x00"
            + NS(b"ssh-rsa")
            + NS(blob)
        )
        d = self.authServer.ssh_USERAUTH_REQUEST(packet)

        return d.addCallback(self._checkFailed)

    def test_ignoreUnknownCredInterfaces(self):
        """
        L{SSHUserAuthServer} sets up
        C{SSHUserAuthServer.supportedAuthentications} by checking the portal's
        credentials interfaces and mapping them to SSH authentication method
        strings.  If the Portal advertises an interface that
        L{SSHUserAuthServer} can't map, it should be ignored.  This is a white
        box test.
        """
        server = userauth.SSHUserAuthServer()
        server.transport = FakeTransport(self.portal)
        self.portal.registerChecker(AnonymousChecker())
        server.serviceStarted()
        server.serviceStopped()
        server.supportedAuthentications.sort()  # give a consistent order
        self.assertEqual(server.supportedAuthentications, [b"password", b"publickey"])

    def test_removePasswordIfUnencrypted(self):
        """
        Test that the userauth service does not advertise password
        authentication if the password would be send in cleartext.
        """
        self.assertIn(b"password", self.authServer.supportedAuthentications)
        # no encryption
        clearAuthServer = userauth.SSHUserAuthServer()
        clearAuthServer.transport = FakeTransport(self.portal)
        clearAuthServer.transport.isEncrypted = lambda x: False
        clearAuthServer.serviceStarted()
        clearAuthServer.serviceStopped()
        self.assertNotIn(b"password", clearAuthServer.supportedAuthentications)
        # only encrypt incoming (the direction the password is sent)
        halfAuthServer = userauth.SSHUserAuthServer()
        halfAuthServer.transport = FakeTransport(self.portal)
        halfAuthServer.transport.isEncrypted = lambda x: x == "in"
        halfAuthServer.serviceStarted()
        halfAuthServer.serviceStopped()
        self.assertIn(b"password", halfAuthServer.supportedAuthentications)

    def test_unencryptedConnectionWithoutPasswords(self):
        """
        If the L{SSHUserAuthServer} is not advertising passwords, then an
        unencrypted connection should not cause any warnings or exceptions.
        This is a white box test.
        """
        # create a Portal without password authentication
        portal = Portal(self.realm)
        portal.registerChecker(PrivateKeyChecker())

        # no encryption
        clearAuthServer = userauth.SSHUserAuthServer()
        clearAuthServer.transport = FakeTransport(portal)
        clearAuthServer.transport.isEncrypted = lambda x: False
        clearAuthServer.serviceStarted()
        clearAuthServer.serviceStopped()
        self.assertEqual(clearAuthServer.supportedAuthentications, [b"publickey"])

        # only encrypt incoming (the direction the password is sent)
        halfAuthServer = userauth.SSHUserAuthServer()
        halfAuthServer.transport = FakeTransport(portal)
        halfAuthServer.transport.isEncrypted = lambda x: x == "in"
        halfAuthServer.serviceStarted()
        halfAuthServer.serviceStopped()
        self.assertEqual(clearAuthServer.supportedAuthentications, [b"publickey"])

    def test_loginTimeout(self):
        """
        Test that the login times out.
        """
        timeoutAuthServer = userauth.SSHUserAuthServer()
        timeoutAuthServer.clock = task.Clock()
        timeoutAuthServer.transport = FakeTransport(self.portal)
        timeoutAuthServer.serviceStarted()
        timeoutAuthServer.clock.advance(11 * 60 * 60)
        timeoutAuthServer.serviceStopped()
        self.assertEqual(
            timeoutAuthServer.transport.packets,
            [
                (
                    transport.MSG_DISCONNECT,
                    b"\x00" * 3
                    + bytes((transport.DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,))
                    + NS(b"you took too long")
                    + NS(b""),
                )
            ],
        )
        self.assertTrue(timeoutAuthServer.transport.lostConnection)

    def test_cancelLoginTimeout(self):
        """
        Test that stopping the service also stops the login timeout.
        """
        timeoutAuthServer = userauth.SSHUserAuthServer()
        timeoutAuthServer.clock = task.Clock()
        timeoutAuthServer.transport = FakeTransport(self.portal)
        timeoutAuthServer.serviceStarted()
        timeoutAuthServer.serviceStopped()
        timeoutAuthServer.clock.advance(11 * 60 * 60)
        self.assertEqual(timeoutAuthServer.transport.packets, [])
        self.assertFalse(timeoutAuthServer.transport.lostConnection)

    def test_tooManyAttempts(self):
        """
        Test that the server disconnects if the client fails authentication
        too many times.
        """
        packet = b"".join([NS(b"foo"), NS(b"none"), NS(b"password"), b"\0", NS(b"bar")])
        self.authServer.clock = task.Clock()
        for i in range(21):
            d = self.authServer.ssh_USERAUTH_REQUEST(packet)
            self.authServer.clock.advance(2)

        def check(ignored):
            self.assertEqual(
                self.authServer.transport.packets[-1],
                (
                    transport.MSG_DISCONNECT,
                    b"\x00" * 3
                    + bytes((transport.DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE,))
                    + NS(b"too many bad auths")
                    + NS(b""),
                ),
            )

        return d.addCallback(check)

    def test_failIfUnknownService(self):
        """
        If the user requests a service that we don't support, the
        authentication should fail.
        """
        packet = NS(b"foo") + NS(b"") + NS(b"password") + b"\0" + NS(b"foo")
        self.authServer.clock = task.Clock()
        d = self.authServer.ssh_USERAUTH_REQUEST(packet)
        return d.addCallback(self._checkFailed)

    def test_tryAuthEdgeCases(self):
        """
        tryAuth() has two edge cases that are difficult to reach.

        1) an authentication method auth_* returns None instead of a Deferred.
        2) an authentication type that is defined does not have a matching
           auth_* method.

        Both these cases should return a Deferred which fails with a
        ConchError.
        """

        def mockAuth(packet):
            return None

        self.patch(self.authServer, "auth_publickey", mockAuth)  # first case
        self.patch(self.authServer, "auth_password", None)  # second case

        def secondTest(ignored):
            d2 = self.authServer.tryAuth(b"password", None, None)
            return self.assertFailure(d2, ConchError)

        d1 = self.authServer.tryAuth(b"publickey", None, None)
        return self.assertFailure(d1, ConchError).addCallback(secondTest)


class SSHUserAuthClientTests(unittest.TestCase):
    """
    Tests for SSHUserAuthClient.
    """

    if keys is None:
        skip = "cannot run without cryptography"

    def setUp(self):
        self.authClient = ClientUserAuth(b"foo", FakeTransport.Service())
        self.authClient.transport = FakeTransport(None)
        self.authClient.transport.sessionID = b"test"
        self.authClient.serviceStarted()

    def tearDown(self):
        self.authClient.serviceStopped()
        self.authClient = None

    def test_init(self):
        """
        Test that client is initialized properly.
        """
        self.assertEqual(self.authClient.user, b"foo")
        self.assertEqual(self.authClient.instance.name, b"nancy")
        self.assertEqual(
            self.authClient.transport.packets,
            [(userauth.MSG_USERAUTH_REQUEST, NS(b"foo") + NS(b"nancy") + NS(b"none"))],
        )

    def test_USERAUTH_SUCCESS(self):
        """
        Test that the client succeeds properly.
        """
        instance = [None]

        def stubSetService(service):
            instance[0] = service

        self.authClient.transport.setService = stubSetService
        self.authClient.ssh_USERAUTH_SUCCESS(b"")
        self.assertEqual(instance[0], self.authClient.instance)

    def test_publickey(self):
        """
        Test that the client can authenticate with a public key.
        """
        self.authClient.ssh_USERAUTH_FAILURE(NS(b"publickey") + b"\x00")
        self.assertEqual(
            self.authClient.transport.packets[-1],
            (
                userauth.MSG_USERAUTH_REQUEST,
                NS(b"foo")
                + NS(b"nancy")
                + NS(b"publickey")
                + b"\x00"
                + NS(b"ssh-dss")
                + NS(keys.Key.fromString(keydata.publicDSA_openssh).blob()),
            ),
        )
        # that key isn't good
        self.authClient.ssh_USERAUTH_FAILURE(NS(b"publickey") + b"\x00")
        blob = NS(keys.Key.fromString(keydata.publicRSA_openssh).blob())
        self.assertEqual(
            self.authClient.transport.packets[-1],
            (
                userauth.MSG_USERAUTH_REQUEST,
                (
                    NS(b"foo")
                    + NS(b"nancy")
                    + NS(b"publickey")
                    + b"\x00"
                    + NS(b"ssh-rsa")
                    + blob
                ),
            ),
        )
        self.authClient.ssh_USERAUTH_PK_OK(
            NS(b"ssh-rsa") + NS(keys.Key.fromString(keydata.publicRSA_openssh).blob())
        )
        sigData = (
            NS(self.authClient.transport.sessionID)
            + bytes((userauth.MSG_USERAUTH_REQUEST,))
            + NS(b"foo")
            + NS(b"nancy")
            + NS(b"publickey")
            + b"\x01"
            + NS(b"ssh-rsa")
            + blob
        )
        obj = keys.Key.fromString(keydata.privateRSA_openssh)
        self.assertEqual(
            self.authClient.transport.packets[-1],
            (
                userauth.MSG_USERAUTH_REQUEST,
                NS(b"foo")
                + NS(b"nancy")
                + NS(b"publickey")
                + b"\x01"
                + NS(b"ssh-rsa")
                + blob
                + NS(obj.sign(sigData)),
            ),
        )

    def test_publickey_without_privatekey(self):
        """
        If the SSHUserAuthClient doesn't return anything from signData,
        the client should start the authentication over again by requesting
        'none' authentication.
        """
        authClient = ClientAuthWithoutPrivateKey(b"foo", FakeTransport.Service())

        authClient.transport = FakeTransport(None)
        authClient.transport.sessionID = b"test"
        authClient.serviceStarted()
        authClient.tryAuth(b"publickey")
        authClient.transport.packets = []
        self.assertIsNone(authClient.ssh_USERAUTH_PK_OK(b""))
        self.assertEqual(
            authClient.transport.packets,
            [(userauth.MSG_USERAUTH_REQUEST, NS(b"foo") + NS(b"nancy") + NS(b"none"))],
        )

    def test_no_publickey(self):
        """
        If there's no public key, auth_publickey should return a Deferred
        called back with a False value.
        """
        self.authClient.getPublicKey = lambda x: None
        d = self.authClient.tryAuth(b"publickey")

        def check(result):
            self.assertFalse(result)

        return d.addCallback(check)

    def test_password(self):
        """
        Test that the client can authentication with a password.  This
        includes changing the password.
        """
        self.authClient.ssh_USERAUTH_FAILURE(NS(b"password") + b"\x00")
        self.assertEqual(
            self.authClient.transport.packets[-1],
            (
                userauth.MSG_USERAUTH_REQUEST,
                NS(b"foo") + NS(b"nancy") + NS(b"password") + b"\x00" + NS(b"foo"),
            ),
        )
        self.authClient.ssh_USERAUTH_PK_OK(NS(b"") + NS(b""))
        self.assertEqual(
            self.authClient.transport.packets[-1],
            (
                userauth.MSG_USERAUTH_REQUEST,
                NS(b"foo") + NS(b"nancy") + NS(b"password") + b"\xff" + NS(b"foo") * 2,
            ),
        )

    def test_no_password(self):
        """
        If getPassword returns None, tryAuth should return False.
        """
        self.authClient.getPassword = lambda: None
        self.assertFalse(self.authClient.tryAuth(b"password"))

    def test_keyboardInteractive(self):
        """
        Make sure that the client can authenticate with the keyboard
        interactive method.
        """
        self.authClient.ssh_USERAUTH_PK_OK_keyboard_interactive(
            NS(b"")
            + NS(b"")
            + NS(b"")
            + b"\x00\x00\x00\x01"
            + NS(b"Password: ")
            + b"\x00"
        )
        self.assertEqual(
            self.authClient.transport.packets[-1],
            (
                userauth.MSG_USERAUTH_INFO_RESPONSE,
                b"\x00\x00\x00\x02" + NS(b"foo") + NS(b"foo"),
            ),
        )

    def test_USERAUTH_PK_OK_unknown_method(self):
        """
        If C{SSHUserAuthClient} gets a MSG_USERAUTH_PK_OK packet when it's not
        expecting it, it should fail the current authentication and move on to
        the next type.
        """
        self.authClient.lastAuth = b"unknown"
        self.authClient.transport.packets = []
        self.authClient.ssh_USERAUTH_PK_OK(b"")
        self.assertEqual(
            self.authClient.transport.packets,
            [(userauth.MSG_USERAUTH_REQUEST, NS(b"foo") + NS(b"nancy") + NS(b"none"))],
        )

    def test_USERAUTH_FAILURE_sorting(self):
        """
        ssh_USERAUTH_FAILURE should sort the methods by their position
        in SSHUserAuthClient.preferredOrder.  Methods that are not in
        preferredOrder should be sorted at the end of that list.
        """

        def auth_firstmethod():
            self.authClient.transport.sendPacket(255, b"here is data")

        def auth_anothermethod():
            self.authClient.transport.sendPacket(254, b"other data")
            return True

        self.authClient.auth_firstmethod = auth_firstmethod
        self.authClient.auth_anothermethod = auth_anothermethod

        # although they shouldn't get called, method callbacks auth_* MUST
        # exist in order for the test to work properly.
        self.authClient.ssh_USERAUTH_FAILURE(NS(b"anothermethod,password") + b"\x00")
        # should send password packet
        self.assertEqual(
            self.authClient.transport.packets[-1],
            (
                userauth.MSG_USERAUTH_REQUEST,
                NS(b"foo") + NS(b"nancy") + NS(b"password") + b"\x00" + NS(b"foo"),
            ),
        )
        self.authClient.ssh_USERAUTH_FAILURE(
            NS(b"firstmethod,anothermethod,password") + b"\xff"
        )
        self.assertEqual(
            self.authClient.transport.packets[-2:],
            [(255, b"here is data"), (254, b"other data")],
        )

    def test_disconnectIfNoMoreAuthentication(self):
        """
        If there are no more available user authentication messages,
        the SSHUserAuthClient should disconnect with code
        DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE.
        """
        self.authClient.ssh_USERAUTH_FAILURE(NS(b"password") + b"\x00")
        self.authClient.ssh_USERAUTH_FAILURE(NS(b"password") + b"\xff")
        self.assertEqual(
            self.authClient.transport.packets[-1],
            (
                transport.MSG_DISCONNECT,
                b"\x00\x00\x00\x0e"
                + NS(b"no more authentication methods available")
                + b"\x00\x00\x00\x00",
            ),
        )

    def test_ebAuth(self):
        """
        _ebAuth (the generic authentication error handler) should send
        a request for the 'none' authentication method.
        """
        self.authClient.transport.packets = []
        self.authClient._ebAuth(None)
        self.assertEqual(
            self.authClient.transport.packets,
            [(userauth.MSG_USERAUTH_REQUEST, NS(b"foo") + NS(b"nancy") + NS(b"none"))],
        )

    def test_defaults(self):
        """
        getPublicKey() should return None.  getPrivateKey() should return a
        failed Deferred.  getPassword() should return a failed Deferred.
        getGenericAnswers() should return a failed Deferred.
        """
        authClient = userauth.SSHUserAuthClient(b"foo", FakeTransport.Service())
        self.assertIsNone(authClient.getPublicKey())

        def check(result):
            result.trap(NotImplementedError)
            d = authClient.getPassword()
            return d.addCallback(self.fail).addErrback(check2)

        def check2(result):
            result.trap(NotImplementedError)
            d = authClient.getGenericAnswers(None, None, None)
            return d.addCallback(self.fail).addErrback(check3)

        def check3(result):
            result.trap(NotImplementedError)

        d = authClient.getPrivateKey()
        return d.addCallback(self.fail).addErrback(check)


class LoopbackTests(unittest.TestCase):
    if keys is None:
        skip = "cannot run without cryptography"

    class Factory:
        class Service:
            name = b"TestService"

            def serviceStarted(self):
                self.transport.loseConnection()

            def serviceStopped(self):
                pass

        def getService(self, avatar, name):
            return self.Service

    def test_loopback(self):
        """
        Test that the userauth server and client play nicely with each other.
        """
        server = userauth.SSHUserAuthServer()
        client = ClientUserAuth(b"foo", self.Factory.Service())

        # set up transports
        server.transport = transport.SSHTransportBase()
        server.transport.service = server
        server.transport.isEncrypted = lambda x: True
        client.transport = transport.SSHTransportBase()
        client.transport.service = client
        server.transport.sessionID = client.transport.sessionID = b""
        # don't send key exchange packet
        server.transport.sendKexInit = client.transport.sendKexInit = lambda: None

        # set up server authentication
        server.transport.factory = self.Factory()
        server.passwordDelay = 0  # remove bad password delay
        realm = Realm()
        portal = Portal(realm)
        checker = SSHProtocolChecker()
        checker.registerChecker(PasswordChecker())
        checker.registerChecker(PrivateKeyChecker())
        checker.areDone = lambda aId: (len(checker.successfulCredentials[aId]) == 2)
        portal.registerChecker(checker)
        server.transport.factory.portal = portal

        d = loopback.loopbackAsync(server.transport, client.transport)
        server.transport.transport.logPrefix = lambda: "_ServerLoopback"
        client.transport.transport.logPrefix = lambda: "_ClientLoopback"

        server.serviceStarted()
        client.serviceStarted()

        def check(ignored):
            self.assertEqual(server.transport.service.name, b"TestService")

        return d.addCallback(check)


class ModuleInitializationTests(unittest.TestCase):
    if keys is None:
        skip = "cannot run without cryptography"

    def test_messages(self):
        # Several message types have value 60, check that MSG_USERAUTH_PK_OK
        # is always the one which is mapped.
        self.assertEqual(
            userauth.SSHUserAuthServer.protocolMessages[60], "MSG_USERAUTH_PK_OK"
        )
        self.assertEqual(
            userauth.SSHUserAuthClient.protocolMessages[60], "MSG_USERAUTH_PK_OK"
        )
¿Qué es la limpieza dental de perros? - Clínica veterinaria


Es la eliminación del sarro y la placa adherida a la superficie de los dientes mediante un equipo de ultrasonidos que garantiza la integridad de las piezas dentales a la vez que elimina en profundidad cualquier resto de suciedad.

A continuación se procede al pulido de los dientes mediante una fresa especial que elimina la placa bacteriana y devuelve a los dientes el aspecto sano que deben tener.

Una vez terminado todo el proceso, se mantiene al perro en observación hasta que se despierta de la anestesia, bajo la atenta supervisión de un veterinario.

¿Cada cuánto tiempo tengo que hacerle una limpieza dental a mi perro?

A partir de cierta edad, los perros pueden necesitar una limpieza dental anual o bianual. Depende de cada caso. En líneas generales, puede decirse que los perros de razas pequeñas suelen acumular más sarro y suelen necesitar una atención mayor en cuanto a higiene dental.


Riesgos de una mala higiene


Los riesgos más evidentes de una mala higiene dental en los perros son los siguientes:

  • Cuando la acumulación de sarro no se trata, se puede producir una inflamación y retracción de las encías que puede descalzar el diente y provocar caídas.
  • Mal aliento (halitosis).
  • Sarro perros
  • Puede ir a más
  • Las bacterias de la placa pueden trasladarse a través del torrente circulatorio a órganos vitales como el corazón ocasionando problemas de endocarditis en las válvulas. Las bacterias pueden incluso acantonarse en huesos (La osteomielitis es la infección ósea, tanto cortical como medular) provocando mucho dolor y una artritis séptica).

¿Cómo se forma el sarro?

El sarro es la calcificación de la placa dental. Los restos de alimentos, junto con las bacterias presentes en la boca, van a formar la placa bacteriana o placa dental. Si la placa no se retira, al mezclarse con la saliva y los minerales presentes en ella, reaccionará formando una costra. La placa se calcifica y se forma el sarro.

El sarro, cuando se forma, es de color blanquecino pero a medida que pasa el tiempo se va poniendo amarillo y luego marrón.

Síntomas de una pobre higiene dental
La señal más obvia de una mala salud dental canina es el mal aliento.

Sin embargo, a veces no es tan fácil de detectar
Y hay perros que no se dejan abrir la boca por su dueño. Por ejemplo…

Recientemente nos trajeron a la clínica a un perro que parpadeaba de un ojo y decía su dueño que le picaba un lado de la cara. Tenía molestias y dificultad para comer, lo que había llevado a sus dueños a comprarle comida blanda (que suele ser un poco más cara y llevar más contenido en grasa) durante medio año. Después de una exploración oftalmológica, nos dimos cuenta de que el ojo tenía una úlcera en la córnea probablemente de rascarse . Además, el canto lateral del ojo estaba inflamado. Tenía lo que en humanos llamamos flemón pero como era un perro de pelo largo, no se le notaba a simple vista. Al abrirle la boca nos llamó la atención el ver una muela llena de sarro. Le realizamos una radiografía y encontramos una fístula que llegaba hasta la parte inferior del ojo.

Le tuvimos que extraer la muela. Tras esto, el ojo se curó completamente con unos colirios y una lentilla protectora de úlcera. Afortunadamente, la úlcera no profundizó y no perforó el ojo. Ahora el perro come perfectamente a pesar de haber perdido una muela.

¿Cómo mantener la higiene dental de tu perro?
Hay varias maneras de prevenir problemas derivados de la salud dental de tu perro.

Limpiezas de dientes en casa
Es recomendable limpiar los dientes de tu perro semanal o diariamente si se puede. Existe una gran variedad de productos que se pueden utilizar:

Pastas de dientes.
Cepillos de dientes o dedales para el dedo índice, que hacen más fácil la limpieza.
Colutorios para echar en agua de bebida o directamente sobre el diente en líquido o en spray.

En la Clínica Tus Veterinarios enseñamos a nuestros clientes a tomar el hábito de limpiar los dientes de sus perros desde que son cachorros. Esto responde a nuestro compromiso con la prevención de enfermedades caninas.

Hoy en día tenemos muchos clientes que limpian los dientes todos los días a su mascota, y como resultado, se ahorran el dinero de hacer limpiezas dentales profesionales y consiguen una mejor salud de su perro.


Limpiezas dentales profesionales de perros y gatos

Recomendamos hacer una limpieza dental especializada anualmente. La realizamos con un aparato de ultrasonidos que utiliza agua para quitar el sarro. Después, procedemos a pulir los dientes con un cepillo de alta velocidad y una pasta especial. Hacemos esto para proteger el esmalte.

La frecuencia de limpiezas dentales necesaria varía mucho entre razas. En general, las razas grandes tienen buena calidad de esmalte, por lo que no necesitan hacerlo tan a menudo e incluso pueden pasarse la vida sin requerir una limpieza. Sin embargo, razas pequeñas como el Yorkshire o el Maltés, deben hacérselas todos los años desde cachorros si se quiere conservar sus piezas dentales.

Otro factor fundamental es la calidad del pienso. Algunas marcas han diseñado croquetas que limpian la superficie del diente y de la muela al masticarse.

Ultrasonido para perros

¿Se necesita anestesia para las limpiezas dentales de perros y gatos?

La limpieza dental en perros no es una técnica que pueda practicarse sin anestesia general , aunque hay veces que los propietarios no quieren anestesiar y si tiene poco sarro y el perro es muy bueno se puede intentar…… , pero no se va a poder pulir ni acceder a todas la zona de la boca …. Además los limpiadores dentales van a irrigar agua y hay riesgo de aspiración a vías respiratorias si no se realiza una anestesia correcta con intubación traqueal . En resumen , sin anestesia no se va hacer una correcta limpieza dental.

Tampoco sirve la sedación ya que necesitamos que el animal esté totalmente quieto, y el veterinario tenga un acceso completo a todas sus piezas dentales y encías.

Alimentos para la limpieza dental

Hay que tener cierto cuidado a la hora de comprar determinados alimentos porque no todos son saludables. Algunos tienen demasiado contenido graso, que en exceso puede causar problemas cardiovasculares y obesidad.

Los mejores alimentos para los dientes son aquellos que están elaborados por empresas farmacéuticas y llevan componentes químicos con tratamientos específicos para el diente del perro. Esto implica no solo limpieza a través de la acción mecánica de morder sino también un tratamiento antibacteriano para prevenir el sarro.

Conclusión

Si eres como la mayoría de dueños, por falta de tiempo , es probable que no estés prestando la suficiente atención a la limpieza dental de tu perro. Por eso te animamos a que comiences a limpiar los dientes de tu perro y consideres atender a su higiene bucal con frecuencia.

Estas simples medidas pueden conllevar a que tu perro tenga una vida más larga y mucho más saludable.

Si te resulta imposible introducir un cepillo de dientes a tu perro en la boca, pásate con él por clínica Tus Veterinarios y te explicamos cómo hacerlo.

Necesitas hacer una limpieza dental profesional a tu mascota?
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