Merge lp:~mwhudson/launchpad/anon-ssh-hack into lp:launchpad

[Michael Hudson-Doyle]

This is just a RFC really. It allows a user called '+anon' to log in to the codehosting ssh server with no credentials and gives them read only access to public branches. I think the code is OK, though maybe it could use a few more comments.

The question, as ever is: is this something we want to do? On the upside, it allow anonymous users access to a smart server transport for public branches, which should be more efficient than accessing http (we could even change bzr to default to using +anon as the username and bzr+ssh when using lp:// branches). On the downside, it will likely create a bit more load on the codehosting server if it became popular.

[lp:~mwhudson/launchpad/anon-ssh-hack]

13957. By Michael Hudson-Doyle on 2011-11-14

merge devel

Unmerged revisions

13957. By Michael Hudson-Doyle on 2011-11-14

merge devel

13956. By Michael Hudson-Doyle on 2011-09-14

fix the unclean reactor error

13955. By Michael Hudson-Doyle on 2011-09-14

oops

13954. By Michael Hudson-Doyle on 2011-09-14

test for anonymous login (which fails with an UncleanReactorError, grump)

13953. By Michael Hudson-Doyle on 2011-09-14

allow a user called +anon to log in (as LAUNCHPAD_ANONYMOUS) without providing any credentials

=== modified file 'lib/lp/code/xmlrpc/codehosting.py'
--- lib/lp/code/xmlrpc/codehosting.py	2011-08-11 21:24:28 +0000
+++ lib/lp/code/xmlrpc/codehosting.py	2011-11-14 02:22:26 +0000
@@ -107,6 +107,8 @@
     method will do whatever security proxy hackery is required to provide read
     privileges to the Launchpad services.
     """
+    if login_id == 0:
+        login_id = LAUNCHPAD_SERVICES
     if login_id == LAUNCHPAD_SERVICES or login_id == LAUNCHPAD_ANONYMOUS:
         # Don't pass in an actual user. Instead pass in LAUNCHPAD_SERVICES
         # and expect `function` to use `removeSecurityProxy` or similar.

=== modified file 'lib/lp/codehosting/sshserver/daemon.py'
--- lib/lp/codehosting/sshserver/daemon.py	2010-08-20 20:31:18 +0000
+++ lib/lp/codehosting/sshserver/daemon.py	2011-11-14 02:22:26 +0000
@@ -19,15 +19,18 @@
 
 from twisted.conch.interfaces import ISession
 from twisted.conch.ssh import filetransfer
+from twisted.cred import checkers
 from twisted.cred.portal import (
     IRealm,
     Portal,
     )
+from twisted.internet import defer
 from twisted.python import components
 from twisted.web.xmlrpc import Proxy
 from zope.interface import implements
 
 from canonical.config import config
+from lp.code.interfaces.codehosting import LAUNCHPAD_ANONYMOUS
 from lp.codehosting import sftp
 from lp.codehosting.sshserver.session import launch_smart_server
 from lp.services.sshserver.auth import (
@@ -71,16 +74,22 @@
         self.codehosting_proxy = codehosting_proxy
 
     def requestAvatar(self, avatar_id, mind, *interfaces):
-        # Fetch the user's details from the authserver
-        deferred = mind.lookupUserDetails(
-            self.authentication_proxy, avatar_id)
-
-        # Once all those details are retrieved, we can construct the avatar.
-        def got_user_dict(user_dict):
-            avatar = CodehostingAvatar(user_dict, self.codehosting_proxy)
-            return interfaces[0], avatar, avatar.logout
-
-        return deferred.addCallback(got_user_dict)
+        if avatar_id is checkers.ANONYMOUS:
+            avatar = CodehostingAvatar(
+                {'id':0, 'name':LAUNCHPAD_ANONYMOUS},
+                self.codehosting_proxy)
+            return defer.succeed((interfaces[0], avatar, avatar.logout))
+        else:
+            # Fetch the user's details from the authserver
+            deferred = mind.lookupUserDetails(
+                self.authentication_proxy, avatar_id)
+
+            # Once all those details are retrieved, we can construct the avatar.
+            def got_user_dict(user_dict):
+                avatar = CodehostingAvatar(user_dict, self.codehosting_proxy)
+                return interfaces[0], avatar, avatar.logout
+
+            return deferred.addCallback(got_user_dict)
 
 
 def get_portal(authentication_proxy, codehosting_proxy):
@@ -88,6 +97,7 @@
     portal = Portal(Realm(authentication_proxy, codehosting_proxy))
     portal.registerChecker(
         PublicKeyFromLaunchpadChecker(authentication_proxy))
+    portal.registerChecker(checkers.AllowAnonymousAccess())
     return portal
 
 

=== modified file 'lib/lp/services/sshserver/auth.py'
--- lib/lp/services/sshserver/auth.py	2010-08-20 20:31:18 +0000
+++ lib/lp/services/sshserver/auth.py	2011-11-14 02:22:26 +0000
@@ -187,6 +187,12 @@
         d.addErrback(self._ebBadAuth)
         return d
 
+    def tryAuth(self, kind, user, data):
+        if user == '+anon':
+            return self.portal.login(credentials.Anonymous(), None, IConchUser)
+        else:
+            return userauth.SSHUserAuthServer.tryAuth(self, kind, user, data)
+
     def _cbFinishedAuth(self, result):
         ret = userauth.SSHUserAuthServer._cbFinishedAuth(self, result)
         # Tell the avatar about the transport, so we can tie it to the

=== modified file 'lib/lp/services/sshserver/tests/test_auth.py'
--- lib/lp/services/sshserver/tests/test_auth.py	2010-11-09 00:14:40 +0000
+++ lib/lp/services/sshserver/tests/test_auth.py	2011-11-14 02:22:26 +0000
@@ -9,6 +9,7 @@
     AsynchronousDeferredRunTest,
     )
 
+from twisted.cred import checkers
 from twisted.conch.checkers import SSHPublicKeyDatabase
 from twisted.conch.error import ConchError
 from twisted.conch.ssh import userauth
@@ -123,6 +124,8 @@
 
 class TestUserAuthServer(TestCase, UserAuthServerMixin):
 
+    run_tests_with = AsynchronousDeferredRunTest
+
     def setUp(self):
         TestCase.setUp(self)
         UserAuthServerMixin.setUp(self)
@@ -174,6 +177,15 @@
             self.user_auth.tryAuth = tryAuth
             self.user_auth._ebBadAuth = _ebBadAuth
 
+    def test_anonymous_login(self):
+        self.user_auth.serviceStarted()
+        self.addCleanup(self.user_auth.serviceStopped)
+        self.portal.registerChecker(checkers.AllowAnonymousAccess())
+        def checkAnonymousAvatar((interfaces, avatar, logout)):
+            self.assertEqual(checkers.ANONYMOUS, avatar.user_id)
+        self.user_auth.tryAuth('none', '+anon', '').addCallback(
+            checkAnonymousAvatar)
+
 
 class MockChecker(SSHPublicKeyDatabase):
     """A very simple public key checker which rejects all offered credentials.