Mini Shell

# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Tests for L{twisted.conch.openssh_compat}.
"""

import os
from unittest import skipIf

from twisted.conch.ssh._kex import getDHGeneratorAndPrime
from twisted.conch.test import keydata
from twisted.python.filepath import FilePath
from twisted.python.reflect import requireModule
from twisted.test.test_process import MockOS
from twisted.trial.unittest import TestCase

doSkip = False
skipReason = ""
if requireModule("cryptography") and requireModule("pyasn1"):
    from twisted.conch.openssh_compat.factory import OpenSSHFactory
else:
    doSkip = True
    skipReason = "Cannot run without cryptography or PyASN1"

if not hasattr(os, "geteuid"):
    doSkip = True
    skipReason = "geteuid/seteuid not available"


@skipIf(doSkip, skipReason)
class OpenSSHFactoryTests(TestCase):
    """
    Tests for L{OpenSSHFactory}.
    """

    def setUp(self):
        self.factory = OpenSSHFactory()
        self.keysDir = FilePath(self.mktemp())
        self.keysDir.makedirs()
        self.factory.dataRoot = self.keysDir.path
        self.moduliDir = FilePath(self.mktemp())
        self.moduliDir.makedirs()
        self.factory.moduliRoot = self.moduliDir.path

        self.keysDir.child("ssh_host_foo").setContent(b"foo")
        self.keysDir.child("bar_key").setContent(b"foo")
        self.keysDir.child("ssh_host_one_key").setContent(keydata.privateRSA_openssh)
        self.keysDir.child("ssh_host_two_key").setContent(keydata.privateDSA_openssh)
        self.keysDir.child("ssh_host_three_key").setContent(b"not a key content")

        self.keysDir.child("ssh_host_one_key.pub").setContent(keydata.publicRSA_openssh)

        self.moduliDir.child("moduli").setContent(
            b"\n"
            b"#    $OpenBSD: moduli,v 1.xx 2016/07/26 12:34:56 jhacker Exp $i\n"
            b"# Time Type Tests Tries Size Generator Modulus\n"
            b"20030501000000 2 6 100 2047 2 "
            b"FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74"
            b"020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F1437"
            b"4FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED"
            b"EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF05"
            b"98DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB"
            b"9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B"
            b"E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF695581718"
            b"3995497CEA956AE515D2261898FA051015728E5A8AACAA68FFFFFFFFFFFFFFFF"
            b"\n"
        )

        self.mockos = MockOS()
        self.patch(os, "seteuid", self.mockos.seteuid)
        self.patch(os, "setegid", self.mockos.setegid)

    def test_getPublicKeys(self):
        """
        L{OpenSSHFactory.getPublicKeys} should return the available public keys
        in the data directory
        """
        keys = self.factory.getPublicKeys()
        self.assertEqual(len(keys), 1)
        keyTypes = keys.keys()
        self.assertEqual(list(keyTypes), [b"ssh-rsa"])

    def test_getPrivateKeys(self):
        """
        Will return the available private keys in the data directory, ignoring
        key files which failed to be loaded.
        """
        keys = self.factory.getPrivateKeys()
        self.assertEqual(len(keys), 2)
        keyTypes = keys.keys()
        self.assertEqual(set(keyTypes), {b"ssh-rsa", b"ssh-dss"})
        self.assertEqual(self.mockos.seteuidCalls, [])
        self.assertEqual(self.mockos.setegidCalls, [])

    def test_getPrivateKeysAsRoot(self):
        """
        L{OpenSSHFactory.getPrivateKeys} should switch to root if the keys
        aren't readable by the current user.
        """
        keyFile = self.keysDir.child("ssh_host_two_key")
        # Fake permission error by changing the mode
        keyFile.chmod(0000)
        self.addCleanup(keyFile.chmod, 0o777)
        # And restore the right mode when seteuid is called
        savedSeteuid = os.seteuid

        def seteuid(euid):
            keyFile.chmod(0o777)
            return savedSeteuid(euid)

        self.patch(os, "seteuid", seteuid)
        keys = self.factory.getPrivateKeys()
        self.assertEqual(len(keys), 2)
        keyTypes = keys.keys()
        self.assertEqual(set(keyTypes), {b"ssh-rsa", b"ssh-dss"})
        self.assertEqual(self.mockos.seteuidCalls, [0, os.geteuid()])
        self.assertEqual(self.mockos.setegidCalls, [0, os.getegid()])

    def test_getPrimes(self):
        """
        L{OpenSSHFactory.getPrimes} should return the available primes
        in the moduli directory.
        """
        primes = self.factory.getPrimes()
        self.assertEqual(
            primes,
            {
                2048: [getDHGeneratorAndPrime(b"diffie-hellman-group14-sha1")],
            },
        )