Summary:
Give them a big essay about how it's dangerous, but allow them to do it formally.
Because the username is part of the password salt, users must change their passwords after a username change.
Make password reset links work for already-logged-in-users since there's no reason not to (if you have a reset link, you can log out and use it) and it's much less confusing if you get this email and are already logged in.
Depends on: D2651
Test Plan: Changed a user's username to all kinds of crazy things. Clicked reset links in email. Tried to make invalid/nonsense name changes.
Reviewers: btrahan, vrana
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T1303
Differential Revision: https://secure.phabricator.com/D2657
Summary:
See T1303, which presents a reasonable case for inclusion of these characters in valid usernames.
Also, unify username validity handling.
Test Plan: Created a new user with a valid name. Tried to create a new user with an invalid name. Ran unit tests.
Reviewers: btrahan, vrana
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T1303
Differential Revision: https://secure.phabricator.com/D2651
Summary:
- `kill_init.php` said "Moving 1000 files" - I hope that this is not some limit in `FileFinder`.
- [src/infrastructure/celerity] `git mv utils.php map.php; git mv api/utils.php api.php`
- Comment `phutil_libraries` in `.arcconfig` and run `arc liberate`.
NOTE: `arc diff` timed out so I'm pushing it without review.
Test Plan:
/D1234
Browsed around, especially in `applications/repository/worker/commitchangeparser` and `applications/` in general.
Auditors: epriestley
Maniphest Tasks: T1103
Summary:
Allow allowed email addresses to be restricted to certain domains. This implies email must be verified.
This probably isn't QUITE ready for prime-time without a few other tweaks (better administrative tools, notably) but we're nearly there.
Test Plan:
- With no restrictions:
- Registered with OAuth
- Created an account with accountadmin
- Added an email
- With restrictions:
- Tried to OAuth register with a restricted address, was prompted to provide a valid one.
- Tried to OAuth register with a valid address, worked fine.
- Tried to accountadmin a restricted address, got blocked.
- Tried to accountadmin a valid address, worked fine.
- Tried to add a restricted address, blocked.
- Tried to add a valid address, worked fine.
- Created a user with People with an invalid address, got blocked.
- Created a user with People with a valid address, worked fine.
Reviewers: btrahan, csilvers
Reviewed By: csilvers
CC: aran, joe, csilvers
Maniphest Tasks: T1184
Differential Revision: https://secure.phabricator.com/D2581
Summary:
- We currently have some bugs in account creation due to nontransactional user/email editing.
- We save $user, then try to save $email. This may fail for various reasons, commonly because the email isn't unique.
- This leaves us with a $user with no email.
- Also, logging of edits is somewhat inconsistent across various edit mechanisms.
- Move all editing to a `PhabricatorUserEditor` class.
- Handle some broken-data cases more gracefully.
Test Plan:
- Created and edited a user with `accountadmin`.
- Created a user with `add_user.php`
- Created and edited a user with People editor.
- Created a user with OAuth.
- Edited user information via Settings.
- Tried to create an OAuth user with a duplicate email address, got a proper error.
- Tried to create a user via People with a duplicate email address, got a proper error.
Reviewers: btrahan, vrana, jungejason
Reviewed By: btrahan
CC: tberman, aran
Maniphest Tasks: T1184
Differential Revision: https://secure.phabricator.com/D2569
Summary:
Allow installs to require users to verify email addresses before they can use Phabricator. If a user logs in without a verified email address, they're given instructions to verify their address.
This isn't too useful on its own since we don't actually have arbitrary email registration, but the next step is to allow installs to restrict email to only some domains (e.g., @mycompany.com).
Test Plan:
- Verification
- Set verification requirement to `true`.
- Tried to use Phabricator with an unverified account, was told to verify.
- Tried to use Conduit, was given a verification error.
- Verified account, used Phabricator.
- Unverified account, reset password, verified implicit verification, used Phabricator.
- People Admin Interface
- Viewed as admin. Clicked "Administrate User".
- Viewed as non-admin
- Sanity Checks
- Used Conduit normally from web/CLI with a verified account.
- Logged in/out.
- Sent password reset email.
- Created a new user.
- Logged in with an unverified user but with the configuration set to off.
Reviewers: btrahan, vrana, jungejason
Reviewed By: btrahan
CC: aran, csilvers
Maniphest Tasks: T1184
Differential Revision: https://secure.phabricator.com/D2520
Summary:
also fix some bugs where we weren't properly capturing the expiry value or scope of access tokens.
This code isn't the cleanest as some providers don't confirm what scope you've been granted. In that case, assume the access token is of the minimum scope Phabricator requires. This seems more useful to me as only Phabricator at the moment really easily / consistently lets the user increase / decrease the granted scope so its basically always the correct assumption at the time we make it.
Test Plan: linked and unlinked Phabricator, Github, Disqus and Facebook accounts from Phabricator instaneces
Reviewers: epriestley
Reviewed By: epriestley
CC: zeeg, aran, Koolvin
Maniphest Tasks: T1110
Differential Revision: https://secure.phabricator.com/D2431
Summary:
- Move email to a separate table.
- Migrate existing email to new storage.
- Allow users to add and remove email addresses.
- Allow users to verify email addresses.
- Allow users to change their primary email address.
- Convert all the registration/reset/login code to understand these changes.
- There are a few security considerations here but I think I've addressed them. Principally, it is important to never let a user acquire a verified email address they don't actually own. We ensure this by tightening the scoping of token generation rules to be (user, email) specific.
- This should have essentially zero impact on Facebook, but may require some minor changes in the registration code -- I don't exactly remember how it is set up.
Not included here (next steps):
- Allow configuration to restrict email to certain domains.
- Allow configuration to require validated email.
Test Plan:
This is a fairly extensive, difficult-to-test change.
- From "Email Addresses" interface:
- Added new email (verified email verifications sent).
- Changed primary email (verified old/new notificactions sent).
- Resent verification emails (verified they sent).
- Removed email.
- Tried to add already-owned email.
- Created new users with "accountadmin". Edited existing users with "accountadmin".
- Created new users with "add_user.php".
- Created new users with web interface.
- Clicked welcome email link, verified it verified email.
- Reset password.
- Linked/unlinked oauth accounts.
- Logged in with oauth account.
- Logged in with email.
- Registered with Oauth account.
- Tried to register with OAuth account with duplicate email.
- Verified errors for email verification with bad tokens, etc.
Reviewers: btrahan, vrana, jungejason
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T1184
Differential Revision: https://secure.phabricator.com/D2393
Summary: We currently try to do "app login" for all OAuth providers, but not all of them support it in a meaningful way. Particularly, it always fails for Google.
Test Plan: Ran google diagnostics on a working config, no longer got a diagnostic failure.
Reviewers: btrahan, vrana, csilvers
Reviewed By: csilvers
CC: aran
Differential Revision: https://secure.phabricator.com/D2377
Summary: basically by validating we have good user data when we set the user data.
Test Plan: simulated a failure from a phabricator on phabricator oauth scenario. viewed ui that correctly told me there was an error with the provider and to try again.
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, Koolvin
Maniphest Tasks: T1077
Differential Revision: https://secure.phabricator.com/D2337
Summary: we were using the "path" as the next_uri and that drops some delicious get parameters
Test Plan: see T1140; basically re-ran the steps listed there and they passed!
Reviewers: epriestley, njhartwell
Reviewed By: epriestley
CC: aran, Koolvin
Maniphest Tasks: T1140, T1009
Differential Revision: https://secure.phabricator.com/D2299
Summary:
PHP has this crazy [[ http://php.net/arg_separator.output | arg_separator.output ]] INI setting which allows setting different string for URL parameters separator instead of `&` (e.g. in `?a=1&b=2`).
Don't use it for external URLs.
Test Plan: Log in through OAuth.
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, Koolvin
Differential Revision: https://secure.phabricator.com/D2284
Summary:
With invalid session (which happens for me when I change production and dev db but can of course happen in other cases), Phabricator displays an ugly unhandled exception dialog suggesting to logging in again.
But there's no login dialog on that page.
This also changes how users with invalid session are treated on pages not requiring logging.
Previously, an exception was thrown on them. Now they are treated as unlogged users.
Test Plan: Corrupt session, go to /, login.
Reviewers: epriestley
Reviewed By: epriestley
CC: aran
Differential Revision: https://secure.phabricator.com/D2236
Summary:
These are all unambiguously unextensible. Issues I hit:
- Maniphest Change/Diff controllers, just consolidated them.
- Some search controllers incorrectly extend from "Search" but should extend from "SearchBase". This has no runtime effects.
- D1836 introduced a closure, which we don't handle correctly (somewhat on purpose; we target PHP 5.2). See T962.
Test Plan: Ran "testEverythingImplemented" unit test to identify classes extending from `final` classes. Resolved issues.
Reviewers: btrahan
Reviewed By: btrahan
CC: aran, epriestley
Maniphest Tasks: T795
Differential Revision: https://secure.phabricator.com/D1843
Summary:
@vrana patched an important external-CSRF-leaking hole recently (D1558), but
since we are sloppy in building this form it got caught in the crossfire.
We set action to something like "http://this.server.com/oauth/derp/", but that
triggers CSRF protection by removing CSRF tokens from the form. This makes OAuth
login not work.
Instead, use the local path only so we generate a CSRF token.
Test Plan: Registered locally via oauth.
Reviewers: vrana, btrahan
Reviewed By: vrana
CC: aran, epriestley, demo
Maniphest Tasks: T853
Differential Revision: https://secure.phabricator.com/D1597
your own actions
Summary:
- Mail.app on Lion has cumbersome threading rules, see T782. Add an option to
stick "Re: " in front of all threaded mail so it behaves. This is horrible, but
apparently the least-horrible option.
- While I was in there, I added an option for T228.
Test Plan:
- Sent a bunch of threaded and unthreaded mail with varous "Re:" settings,
seemed to get "Re:" in the right places.
- Disabled email about my stuff, created a task with just me, got voided mail,
added a CC, got mail to just the CC.
Reviewers: btrahan, jungejason
Reviewed By: btrahan
CC: aran, mkjones
Maniphest Tasks: T228, T782
Differential Revision: https://secure.phabricator.com/D1448
Summary: Revisit of D1254. Don't require lowercase, just standardize the logic.
The current implementation has nonuniform logic -- PeopleEditController forbids
uppercase.
Test Plan: Ran unit tests, see also D1254.
Reviewers: btrahan, jungejason, aran
Reviewed By: btrahan
CC: aran
Differential Revision: https://secure.phabricator.com/D1415
Summary:
A few people in IRC have been having issues here recently. If you misconfigure
the IRC bot, e.g., you get a 200 response back with a bunch of login HTML in it.
This is unhelpful.
Try to detect that a conduit request is going to the wrong path and raise a
concise, explicit error which is comprehensible from the CLI.
Also created a "PlainText" response and moved the IE nosniff header to the base
response object.
Test Plan: As a logged-out user, hit various nonsense with "?__conduit__=true"
in the URI. Got good error messages. Hit nonsense without it, got login screens.
Reviewers: btrahan, jungejason
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T775
Differential Revision: https://secure.phabricator.com/D1407
Summary:
I locked this down a little bit recently, but make
double-extra-super-sure that we aren't sending the user anywhere suspicious or
open-redirecty. This also locks down protocol-relative URIs (//evil.com/path)
although I don't think any browsers do bad stuff with them in this context, and
header injection URIs (although I don't think any of the modern PHP runtimes are
vulnerable).
Test Plan:
- Ran tests.
- Hit redirect page with valid and invalid next URIs; was punted to / for
invalid ones and to the right place for valid ones.
Reviewers: btrahan, jungejason
Reviewed By: btrahan
CC: arice, aran, epriestley, btrahan
Differential Revision: https://secure.phabricator.com/D1369
Summary: If a remote address has too many recent login failures, require they
fill out a captcha before they can attempt to login.
Test Plan: Tried to login a bunch of times, then submitted the CAPTHCA form with
various combinations of valid/invalid passwords and valid/invalid captchas.
Reviewers: btrahan, jungejason
Reviewed By: jungejason
CC: aran, epriestley, jungejason
Maniphest Tasks: T765
Differential Revision: https://secure.phabricator.com/D1379
interfaces
Summary:
- We have a hard-coded minimum length of 3 right now (and 1 in the other
interface), which is sort of silly.
- Provide a more reasonable default, and allow it to be configured.
- We have two password reset interfaces, one of which no longer actually
requires you to verify you own the account. This is more than a bit derp.
- Merge the interfaces into one, using either an email token or the account's
current password to let you change the password.
Test Plan:
- Reset password on an account.
- Changed password on an account.
- Created a new account, logged in, set the password.
- Tried to set a too-short password, got an error.
Reviewers: btrahan, jungejason, nh
Reviewed By: jungejason
CC: aran, jungejason
Maniphest Tasks: T766
Differential Revision: https://secure.phabricator.com/D1374
Summary:
- There are some recent reports of login issues, see T755 and T754. I'm not
really sure what's going on, but this is an attempt at getting some more
information.
- When we login a user by setting 'phusr' and 'phsid', send them to
/login/validate/ to validate that the cookies actually got set.
- Do email password resets in two steps: first, log the user in. Redirect them
through validate, then give them the option to reset their password.
- Don't CSRF logged-out users. It technically sort of works most of the time
right now, but is silly. If we need logged-out CSRF we should generate it in
some more reliable way.
Test Plan:
- Logged in with username/password.
- Logged in with OAuth.
- Logged in with email password reset.
- Sent bad values to /login/validate/, got appropriate errors.
- Reset password.
- Verified next_uri still works.
Reviewers: btrahan, jungejason
Reviewed By: btrahan
CC: aran, btrahan, j3kuntz
Maniphest Tasks: T754, T755
Differential Revision: https://secure.phabricator.com/D1353
Summary: See comments. A few installs have remarked that their organizations
would prefer buttons labled "Submit" to buttons labeled "Clowncopterize".
Test Plan:
- In "serious" mode, verified Differential and Maniphest have serious strings,
tasks can not be closed out of spite, and reset/welcome emails are extremely
serious.
- In unserious mode, verified Differential and Maniphest have normal strings,
tasks can be closed out of spite, and reset/welcome emails are silly.
- This does not disable the "fax these changes" message in Arcanist (no
reasonable way for it to read the config value) or the rainbow syntax
highlighter (already removable though configuration).
Reviewers: moskov, jungejason, nh, tuomaspelkonen, aran
Reviewed By: moskov
CC: aran, moskov
Differential Revision: 1081
Summary:
This is pretty straightforward, except:
- We need to request read/write access to the address book to get the account
ID (which we MUST have) and real name, email and account name (which we'd like
to have). This is way more access than we should need, but there's apparently no
"get_loggedin_user_basic_information" type of call in the Google API suite (or,
at least, I couldn't find one).
- We can't get the profile picture or profile URI since there's no Plus API
access and Google users don't have meaningful public pages otherwise.
- Google doesn't save the fact that you've authorized the app, so every time
you want to login you need to reaffirm that you want to give us silly amounts of
access. Phabricator sessions are pretty long-duration though so this shouldn't
be a major issue.
Test Plan:
- Registered, logged out, and logged in with Google.
- Registered, logged out, and logged in with Facebook / Github to make sure I
didn't break anything.
- Linked / unlinked Google accounts.
Reviewers: Makinde, jungejason, nh, tuomaspelkonen, aran
Reviewed By: aran
CC: aran, epriestley, Makinde
Differential Revision: 916
Summary:
@tomo ran into an issue where he had some non-SSL-only cookie or whatever, so
"Logout" had no apparent effect. Make sure "Logout" really works by destroying
the session.
I originally kept the sessions around to be able to debug session stuff, but we
have a fairly good session log now and no reprorted session bugs except for all
the cookie stuff. It's also slightly more secure to actually destroy sessions,
since it means "logout" breaks any cookies that attackers somehow stole (e.g.,
by reading your requests off a public wifi network).
Test Plan: Commented out the cookie clear and logged out. I was logged out and
given a useful error message about clearing my cookies.
Reviewers: jungejason, nh, tuomaspelkonen, aran
Reviewed By: aran
CC: tomo, aran, epriestley
Differential Revision: 911
Summary: Open AphrontWriteGuard for user login.
Test Plan: verified that the user can log in.
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, epriestley
Differential Revision: 840
Summary:
Provide a catchall mechanism to find unprotected writes.
- Depends on D758.
- Similar to WriteOnHTTPGet stuff from Facebook's stack.
- Since we have a small number of storage mechanisms and highly structured
read/write pathways, we can explicitly answer the question "is this page
performing a write?".
- Never allow writes without CSRF checks.
- This will probably break some things. That's fine: they're CSRF
vulnerabilities or weird edge cases that we can fix. But don't push to Facebook
for a few days unless you're prepared to deal with this.
- **>>> MEGADERP: All Conduit write APIs are currently vulnerable to CSRF!
<<<**
Test Plan:
- Ran some scripts that perform writes (scripts/search indexers), no issues.
- Performed normal CSRF submits.
- Added writes to an un-CSRF'd page, got an exception.
- Executed conduit methods.
- Did login/logout (this works because the logged-out user validates the
logged-out csrf "token").
- Did OAuth login.
- Did OAuth registration.
Reviewers: pedram, andrewjcg, erling, jungejason, tuomaspelkonen, aran,
codeblock
Commenters: pedram
CC: aran, epriestley, pedram
Differential Revision: 777
Summary:
We currently cycle CSRF tokens every hour and check for the last two valid ones.
This means that a form could go stale in as little as an hour, and is certainly
stale after two.
When a stale form is submitted, you basically get a terrible heisen-state where
some of your data might persist if you're lucky but more likely it all just
vanishes. The .js file below outlines some more details.
This is a pretty terrible UX and we don't need to be as conservative about CSRF
validation as we're being. Remedy this problem by:
- Accepting the last 6 CSRF tokens instead of the last 1 (i.e., pages are
valid for at least 6 hours, and for as long as 7).
- Using JS to refresh the CSRF token every 55 minutes (i.e., pages connected
to the internet are valid indefinitely).
- Showing the user an explicit message about what went wrong when CSRF
validation fails so the experience is less bewildering.
They should now only be able to submit with a bad CSRF token if:
- They load a page, disconnect from the internet for 7 hours, reconnect, and
submit the form within 55 minutes; or
- They are actually the victim of a CSRF attack.
We could eventually fix the first one by tracking reconnects, which might be
"free" once the notification server gets built. It will probably never be an
issue in practice.
Test Plan:
- Reduced CSRF cycle frequency to 2 seconds, submitted a form after 15
seconds, got the CSRF exception.
- Reduced csrf-refresh cycle frequency to 3 seconds, submitted a form after 15
seconds, got a clean form post.
- Added debugging code the the csrf refresh to make sure it was doing sensible
things (pulling different tokens, finding all the inputs).
Reviewed By: aran
Reviewers: tuomaspelkonen, jungejason, aran
CC: aran, epriestley
Differential Revision: 660
Summary:
- have files be uploaded by drag+drop instead of browse.
- Files are named by their uploaded filename, the user isn't given a chance to enter a file name. Is this bad?
- Store author PHID now with files
- Allow an ?author=<username> to limit the /files/ list by author.
- If one file is uploaded, the user is taken to its info page.
- If several are uploaded, they are taken to a list of their files.
Test Plan:
- Quickly tested everything and it still worked, I'd recommend some people try this out before it gets committed though. It's a rather huge revision.
Reviewers:
epriestley, Ttech
CC:
Differential Revision: 612
Summary:
Send the user where they were intending to go after github and localized logins.
Before, because Github didn't send oauthState, we would force / upon them.
Test Plan:
Tried all three methods of login successfully.
Reviewers:
epriestley
CC:
Differential Revision: 602
Summary:
- When an administrator creates a user, provide an option to send a welcome
email. Right now this workflow kind of dead-ends.
- Prevent administrators from changing the "System Agent" flag. If they can
change it, they can grab another user's certificate and then act as them. This
is a vaguely weaker security policy than is exhibited elsewhere in the
application. Instead, make user accounts immutably normal users or system agents
at creation time.
- Prevent administrators from changing email addresses after account creation.
Same deal as conduit certs. The 'bin/accountadmin' script can still do this if a
user has a real problem.
- Prevent administrators from resetting passwords. There's no need for this
anymore with welcome emails plus email login and it raises the same issues.
Test Plan:
- Created a new account, selected "send welcome email", got a welcome email,
logged in with the link inside it.
- Created a new system agent.
- Reset an account's password.
Reviewed By: aran
Reviewers: tuomaspelkonen, jungejason, aran
CC: anjali, aran, epriestley
Differential Revision: 379
Summary:
Allows you to link to comments with "D123#3" or "T123#3", then adds a pile of JS
to try to make it not terrible. :/
The thing I'm trying to avoid here is when someone says "look at this!
http://blog.com/#comment-239291" and you click and your browser jumps somewhere
random and you have no idea which comment they meant. Since I really hate this,
I've tried to avoid it by making sure the comment is always highlighted.
Test Plan:
Put T1#1 and D1#1 in remarkup and verified they linked properly.
Clicked anchors on individual comments.
Faked all comments hidden in Differential and verified they expanded on anchor
or anchor change.
Reviewed By: aran
Reviewers: aran, tomo, mroch, jungejason, tuomaspelkonen
CC: aran, epriestley
Differential Revision: 383
Summary:
Despite the form's claims that you can login with username or email, it actually
accepted only username.
Test Plan:
Logged in using my email.
Reviewed By: jungejason
Reviewers: tuomaspelkonen, jungejason, aran
CC: jr, anjali, aran, jungejason
Differential Revision: 354
Summary: This isn't complete, but I figured I'd ship it for review while it's still smallish.
Provide an activity log for high-level system actions (logins, admin actions). This basically allows two things to happen:
- The log itself is useful if there are shenanigans.
- Password login can check it and start CAPTCHA'ing users after a few failed attempts.
I'm going to change how the admin stuff works a little bit too, since right now you can make someone an agent, grab their certificate, revert them back to a normal user, and then act on their behalf over Conduit. This is a little silly, I'm going to move "agent" to the create workflow instead. I'll also add a confirm/email step to the administrative password reset flow.
Test Plan: Took various administrative and non-administrative actions, they appeared in the logs. Filtered the logs in a bunch of different ways.
Reviewers: jungejason, tuomaspelkonen, aran
CC:
Differential Revision: 302
Summary:
Provide an "isAdmin" flag for users, to designate administrative users.
Restore the account editing interface and allow it to set role flags and reset
passwords.
Provide an "isDisabled" flag for users and shut down all system access for them.
Test Plan:
Created "admin" and "disabled" users. Did administrative things with the admin
user. Tried to do stuff with the disabled user and was rebuffed. Tried to access
administrative interfaces with a normal non-admin user and was denied.
Reviewed By: aran
Reviewers: tuomaspelkonen, jungejason, aran
CC: ccheever, aran
Differential Revision: 278
Summary:
Github allows you to have an account without a real name. The OAuth controller
actually handles this fine, mostly, except that it calls a bogus method. Also
there is some null vs empty string confusion.
Test Plan:
Deleted my name on Github and then registered for an account on Phabricator.
Reviewed By: tuomaspelkonen
Reviewers: jungejason, tuomaspelkonen, aran
CC: anjali, aran, tuomaspelkonen
Differential Revision: 247
Summary:
I pretty shortsightedly made sending a side effect of save() in the case that a
server is configured for immediate sending. Move this out, make it explicit, and
get rid of all the tangles surrounding it.
The web tool now ignores the server setting and only repsects the checkbox,
which makes far more sense.
Test Plan:
Sent mails from Maniphest, Differential, and the web console. Also ran all the
unit tests. Verified headers from Maniphest.
Reviewed By: rm
Reviewers: aran, rm
CC: tuomaspelkonen, rm, jungejason, aran
Differential Revision: 200
Summary:
There's an OAuth diagnostics page at /oauth/facebook/diagnose/, which
shows some diagnostic information. Currently, it attempts to establish an
application token session and shows the token if it is successful. An attacker
could use this to do vaguely nefarious things (retreive application statistics,
I think?).
This interface was originally admin-only but then I threw out the very silly
admin mode patch I had at the time and we currently have no admin mode, and
thus this interface is public. This token isn't useful in diagnosis anyway,
so don't reveal it.
Test Plan:
Visited oauth diagnostics page, no token revealed
Reviewed By: tuomaspelkonen
Reviewers: tuomaspelkonen, jungejason
CC: tuomaspelkonen
Differential Revision: 136
Summary:
When a user clicks a link like /T32 and has to login, redirect them
to the resource once they've authenticated if possible. OAuth has a param
specifically for this, called 'state', so use it if possible. Facebook
supports it but Github does not.
Test Plan:
logged in with facebook after viewing /D20
Reviewed By: aran
Reviewers: aran
CC: aran, epriestley
Differential Revision: 61
