From: Jean-Paul Calderone Date: Sun, 4 Jan 2015 14:44:56 +0000 (-0500) Subject: Add the rest of the failure-case tests and a success-case test. Update the implement... X-Git-Tag: allmydata-tahoe-1.10.1a1~91 X-Git-Url: https://git.rkrishnan.org/specifications/install.html?a=commitdiff_plain;h=38aee94a3eb3c007cc6cb1d7cb5b04b66f5d8f99;p=tahoe-lafs%2Ftahoe-lafs.git Add the rest of the failure-case tests and a success-case test. Update the implementation to make them pass. --- diff --git a/src/allmydata/frontends/auth.py b/src/allmydata/frontends/auth.py index 82ef1c65..745adbe8 100644 --- a/src/allmydata/frontends/auth.py +++ b/src/allmydata/frontends/auth.py @@ -3,6 +3,9 @@ from zope.interface import implements from twisted.web.client import getPage from twisted.internet import defer from twisted.cred import error, checkers, credentials +from twisted.conch import error as conch_error +from twisted.conch.ssh import keys + from allmydata.util import base32 class NeedRootcapLookupScheme(Exception): @@ -18,7 +21,8 @@ class FTPAvatarID: class AccountFileChecker: implements(checkers.ICredentialsChecker) credentialInterfaces = (credentials.IUsernamePassword, - credentials.IUsernameHashedPassword) + credentials.IUsernameHashedPassword, + credentials.ISSHPrivateKey) def __init__(self, client, accountfile): self.client = client self.passwords = {} @@ -31,7 +35,7 @@ class AccountFileChecker: name, passwd, rest = line.split(None, 2) if passwd in ("ssh-dss", "ssh-rsa"): bits = rest.split() - keystring = " ".join(bits[-1]) + keystring = " ".join([passwd] + bits[:-1]) rootcap = bits[-1] self.pubkeys[name] = keystring else: @@ -44,12 +48,69 @@ class AccountFileChecker: return FTPAvatarID(username, self.rootcaps[username]) raise error.UnauthorizedLogin - def requestAvatarId(self, credentials): - if credentials.username in self.passwords: - d = defer.maybeDeferred(credentials.checkPassword, - self.passwords[credentials.username]) - d.addCallback(self._cbPasswordMatch, str(credentials.username)) - return d + def requestAvatarId(self, creds): + if credentials.ISSHPrivateKey.providedBy(creds): + # Re-using twisted.conch.checkers.SSHPublicKeyChecker here, rather + # than re-implementing all of the ISSHPrivateKey checking logic, + # would be better. That would require Twisted 14.1.0 or newer, + # though. + return self._checkKey(creds) + elif credentials.IUsernameHashedPassword.providedBy(creds): + return self._checkPassword(creds) + elif credentials.IUsernamePassword.providedBy(creds): + return self._checkPassword(creds) + else: + raise NotImplementedError() + + def _checkPassword(self, creds): + """ + Determine whether the password in the given credentials matches the + password in the account file. + + Returns a Deferred that fires with the username if the password matches + or with an UnauthorizedLogin failure otherwise. + """ + try: + correct = self.passwords[creds.username] + except KeyError: + return defer.fail(error.UnauthorizedLogin()) + + d = defer.maybeDeferred(creds.checkPassword, correct) + d.addCallback(self._cbPasswordMatch, str(creds.username)) + return d + + def _allowedKey(self, creds): + """ + Determine whether the public key indicated by the given credentials is + one allowed to authenticate the username in those credentials. + + Returns True if so, False otherwise. + """ + return creds.blob == self.pubkeys.get(creds.username) + + def _correctSignature(self, creds): + """ + Determine whether the signature in the given credentials is the correct + signature for the data in those credentials. + + Returns True if so, False otherwise. + """ + key = keys.Key.fromString(creds.blob) + return key.verify(creds.signature, creds.sigData) + + def _checkKey(self, creds): + """ + Determine whether some key-based credentials correctly authenticates a + user. + + Returns a Deferred that fires with the username if so or with an + UnauthorizedLogin failure otherwise. + """ + if self._allowedKey(creds): + if creds.signature is None: + return defer.fail(conch_error.ValidPublicKey()) + if self._correctSignature(creds): + return defer.succeed(creds.username) return defer.fail(error.UnauthorizedLogin()) class AccountURLChecker: diff --git a/src/allmydata/test/test_auth.py b/src/allmydata/test/test_auth.py index 52705788..46c2fbfb 100644 --- a/src/allmydata/test/test_auth.py +++ b/src/allmydata/test/test_auth.py @@ -1,6 +1,7 @@ from twisted.trial import unittest from twisted.python import filepath from twisted.cred import error, credentials +from twisted.conch import error as conch_error from twisted.conch.ssh import keys from allmydata.frontends import auth @@ -26,8 +27,8 @@ dBSD8940XU3YW+oeq8e+p3yQ2GinHfeJ3BYQyNQLuMAJ DUMMY_ACCOUNTS = u"""\ alice password URI:DIR2:aaaaaaaaaaaaaaaaaaaaaaaaaa:1111111111111111111111111111111111111111111111111111 bob sekrit URI:DIR2:bbbbbbbbbbbbbbbbbbbbbbbbbb:2222222222222222222222222222222222222222222222222222 -carol %(key)s URI:DIR2:cccccccccccccccccccccccccc:3333333333333333333333333333333333333333333333333333 -""".format(DUMMY_KEY.public().toString("openssh")).encode("ascii") +carol {key} URI:DIR2:cccccccccccccccccccccccccc:3333333333333333333333333333333333333333333333333333 +""".format(key=DUMMY_KEY.public().toString("openssh")).encode("ascii") class AccountFileCheckerKeyTests(unittest.TestCase): """ @@ -49,6 +50,17 @@ class AccountFileCheckerKeyTests(unittest.TestCase): avatarId = self.checker.requestAvatarId(key_credentials) return self.assertFailure(avatarId, error.UnauthorizedLogin) + def test_password_auth_user(self): + """ + AccountFileChecker.requestAvatarId returns a Deferred that fires with + UnauthorizedLogin if called with an SSHPrivateKey object for a username + only associated with a password in the account file. + """ + key_credentials = credentials.SSHPrivateKey( + b"alice", b"md5", None, None, None) + avatarId = self.checker.requestAvatarId(key_credentials) + return self.assertFailure(avatarId, error.UnauthorizedLogin) + def test_unrecognized_key(self): """ AccountFileChecker.requestAvatarId returns a Deferred that fires with @@ -63,3 +75,45 @@ ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAYQDJGMWlPXh2M3pYzTiamjcBIMqctt4VvLVW2QZgEFc8 b"carol", b"md5", wrong_key_blob, None, None) avatarId = self.checker.requestAvatarId(key_credentials) return self.assertFailure(avatarId, error.UnauthorizedLogin) + + def test_missing_signature(self): + """ + AccountFileChecker.requestAvatarId returns a Deferred that fires with + ValidPublicKey if called with an SSHPrivateKey object with an + authorized key for the indicated user but with no signature. + """ + right_key_blob = DUMMY_KEY.public().toString("openssh") + key_credentials = credentials.SSHPrivateKey( + b"carol", b"md5", right_key_blob, None, None) + avatarId = self.checker.requestAvatarId(key_credentials) + return self.assertFailure(avatarId, conch_error.ValidPublicKey) + + def test_wrong_signature(self): + """ + AccountFileChecker.requestAvatarId returns a Deferred that fires with + UnauthorizedLogin if called with an SSHPrivateKey object with a public + key matching that on the user's line in the account file but with the + wrong signature. + """ + right_key_blob = DUMMY_KEY.public().toString("openssh") + key_credentials = credentials.SSHPrivateKey( + b"carol", b"md5", right_key_blob, b"signed data", b"wrong sig") + avatarId = self.checker.requestAvatarId(key_credentials) + return self.assertFailure(avatarId, error.UnauthorizedLogin) + + def test_authenticated(self): + """ + AccountFileChecker.requestAvatarId returns a Deferred that fires with + the username portion of the account file line that matches the username + and key blob portion of the SSHPrivateKey object if that object also + has a correct signature. + """ + username = b"carol" + signed_data = b"signed data" + signature = DUMMY_KEY.sign(signed_data) + right_key_blob = DUMMY_KEY.public().toString("openssh") + key_credentials = credentials.SSHPrivateKey( + username, b"md5", right_key_blob, signed_data, signature) + avatarId = self.checker.requestAvatarId(key_credentials) + avatarId.addCallback(self.assertEqual, username) + return avatarId