This commit removes the 'experimental_preconnect_link_header' site setting, and the 'preload_link_header' site setting, and introduces two new global settings: early_hint_header_mode and early_hint_header_name.
We don't actually send 103 Early Hint responses from Discourse. However, upstream proxies can be configured to cache a response header from the app and use that to send an Early Hint response to future clients.
- `early_hint_header_mode` specifies the mode for the early hint header. Can be nil (disabled), "preconnect" (lists just CDN domains) or "preload" (lists all assets).
- `early_hint_header_name` specifies which header name to use for the early hint. Defaults to "Link", but can be changed to support different proxy mechanisms.
Previously, when crawlers triggered a Discourse::InvalidAccess exception, they would be served the full Ember SPA. The SPA is not optimized for crawling, and so this is likely to cause problems for sites. This issue is particularly problematic when user profiles are hidden from the public via the `hide_user_profiles_from_public` setting, because the crawler would end up being 'soft-redirected' to the homepage in the SPA.
Why this change?
In https://web.dev/articles/preconnect-and-dns-prefetch, it describes
how hinting to the browser to preconnect to domains which we will
eventually use the connection for can help improve the time it takes to
load a page.
We are putting this behind an experimental flag so that we can test and
profile this in a production environment.
What does this change introduce?
Introduce a hidden experimental `experimental_preconnect_link_header`
site setting which when enabled will add the `preconnect` and
`dns-prefetch` resource hints to the response headers for full page load
requests.
With the new admin sidebar restructure, we have a link to "Installed plugins". We would like to ensure that when the admin is searching for a plugin name like "akismet" or "automation" this link will be visible. Also when entering the plugins page, related plugins should be highlighted.
When we show the links to installed plugins in the admin
sidebar (for plugins that have custom admin routes) we were
previously only doing this if you opened /admin, not if you
navigated there from the main forum. We should just always
preload this data if the user is admin.
This commit also changes `admin_sidebar_enabled_groups` to
not be sent to the client as part of ongoing efforts to
not check groups on the client, since not all a user's groups
may be serialized.
In a handful of situations, we need to verify a user's 2fa credentials before `current_user` is assigned. For example: login, email_login and change-email confirmation. This commit adds an explicit `target_user:` parameter to the centralized 2fa system so that it can be used for those situations.
For safety and clarity, this new parameter only works for anon. If some user is logged in, and target_user is set to a different user, an exception will be raised.
This changes the Plugins link in the admin sidebar to
be a section instead, which then shows all enabled plugin
admin routes (which are custom routes some plugins e.g.
chat define).
This is done via adding some special preloaded data for
all controllers based on AdminController, and also specifically
on Admin::PluginsController, to have the routes loaded without
additional requests on page load.
We just use a cog for all the route icons for now...we don't
have anything better.
Why this change?
This is part of our efforts to harden the security of the Discourse
application. Setting the `CROSS_ORIGIN_OPENER_POLICY` header to `same-origin-allow-popups`
by default makes the application safer. We have opted to make this a
hidden site setting because most admins will never have to care about
this setting so we're are opting not to show it. If they do have to
change it, they can still do so by setting the
`DISCOURSE_CROSS_ORIGIN_OPENER_POLICY` env.
Some sites have a large number of categories and fetching the category
IDs or category topic IDs just to build another query can take a long
time or resources (i.e. memory).
Why this change?
As part of our ongoing efforts to security harden the Discourse
application, we are adding the `cross_origin_opener_policy_header` site setting
which allows the `Cross-Origin-Opener-Policy` response header to be set on requests
that preloads the Discourse application. In more technical terms, only
GET requests that are not json or xhr will have the response header set.
The `cross_origin_opener_policy_header` site setting is hidden for now
for testing purposes and will either be released as a public site
setting or be remove if we decide to be opinionated and ship a default
for the `Cross-Origin-Opener-Policy` response header.
What is the problem here?
In multiple controllers, we are accepting a `limit` params but do not
impose any upper bound on the values being accepted. Without an upper
bound, we may be allowing arbituary users from generating DB queries
which may end up exhausing the resources on the server.
What is the fix here?
A new `fetch_limit_from_params` helper method is introduced in
`ApplicationController` that can be used by controller actions to safely
get the limit from the params as a default limit and maximum limit has
to be set. When an invalid limit params is encountered, the server will
respond with the 400 response code.
Some plugins call require_plugin with a wrong argument instead of the
plugin name. In a production environment that used to be a warning, but
there is no reason to keep it like that in a testing environment
because the issue will continue to be ignored.
]When changing fonts in the `/wizard/steps/styling` step of
the wizard, users would not see the font loaded straight away,
having to switch to another one then back to the original to
see the result. This is because we are using canvas to render
the style preview and this fails with a Chrome-based intervention
when font loading is taking too long:
> [Intervention] Slow network is detected. See
https://www.chromestatus.com/feature/5636954674692096 for more details.
Fallback font will be used while loading:
https://sea2.discourse-cdn.com/business7/fonts/Roboto-Bold.ttf?v=0.0.9
We can get around this by manually loading the fonts selected using
the FontFace JS API when the user selects them and before rerendering
the canvas. This just requires preloading more information about the
fonts if the user is admin so the wizard can query this data.
This corrects two issues:
1. We were double serializing topic tracking state (as_json calls were not cached)
2. We were inefficiently serializing items by instantiating extra objects
What does this change do?
This commit the client to override the navigation menu setting
configured by the site temporarily based on the value of the
`navigation_menu` query param. The new query param replaces the old
`enable_sidebar` query param.
Why do we need this change?
The motivation here is to allow theme maintainers to quickly preview
what the site will look like with the various navigation menu site
setting.
## Why do we need this change?
When loading the ember app, [MessageBus does not start polling immediately](f31f0b70f8/app/assets/javascripts/discourse/app/initializers/message-bus.js (L71-L81)) and instead waits for `document.readyState` to be `complete`. What this means is that if there are new messages being created while we have yet to start polling, those messages will not be received by the client.
With sidebar being the default navigation menu, the counts derived from `topic-tracking-state.js` on the client side is prominently displayed on every page. Therefore, we want to ensure that we are not dropping any messages on the channels that `topic-tracking-state.js` subscribes to.
## What does this change do?
This includes the `MessageBus.last_id`s for the MessageBus channels which `topic-tracking-state.js` subscribes to as part of the preloaded data when loading a page. The last ids are then used when we subscribe the MessageBus channels so that messages which are published before MessageBus starts polling will not be missed.
## Review Notes
1. See https://github.com/discourse/message_bus#client-support for documentation about subscribing from a given message id.
* Revert "Revert "FEATURE: Preload resources via link header (#18475)" (#18511)"
This reverts commit 95a57f7e0c.
* put behind feature flag
* env -> global setting
* declare global setting
* forgot one spot
Experiment moving from preload tags in the document head to preload information the the response headers.
While this is a minor improvement in most browsers (headers are parsed before the response body), this allows smart proxies like Cloudflare to "learn" from those headers and build HTTP 103 Early Hints for subsequent requests to the same URI, which will allow the user agent to download and parse our JS/CSS while we are waiting for the server to generate and stream the HTML response.
Co-authored-by: Penar Musaraj <pmusaraj@gmail.com>
- `no_custom` -> `no_themes` (history: before themes existed, we had a similar tool called 'customizations')
- `only_official` -> `no_unofficial_plugins` (matches format of `no_themes` and `no_plugins`, and makes it clear that this doesn't affect themes)
- `?safe_mode=no_themes%2C%no_plugins` -> `?safe_mode=no_themes,no_plugins` (the query portion of a URL does not require commas to be encoded. This is much nicer to read)
- If `no_plugins` is chosen from `/safe-mode` the URL generated will omit the superfluous `no_unofficial_plugins` flag
- Some tweaks to copy on `/safe-mode`
Some errors (e.g. InvalidAccess) are rendered with `include_ember: true`. Booting the ember app requires that the 'preload' data is rendered in the HTML.
If a particular route was configured to `skip_before_action :preload_json`, and then went on to raise an InvalidAccess error, then we'd attempt to render the Ember app without the preload json. This led to a blank screen and a client-side error.
This commit ensures that error pages will fallback to the no_ember view if there is no preload data. It also adds a sanity check in `discourse-bootstrap` so that it's easier for us to identify similar errors in future.
The title had to be added both on the 404 page generated by the server
side, displayed when the user reaches a bad page directly and the 404
page rendered by Ember when a user reaches a missing topic while
navigating the forum.
Discourse has the Discourse Connect Provider protocol that makes it possible to
use a Discourse instance as an identity provider for external sites. As a
natural extension to this protocol, this PR adds a new feature that makes it
possible to use Discourse as a 2FA provider as well as an identity provider.
The rationale for this change is that it's very difficult to implement 2FA
support in a website and if you have multiple websites that need to have 2FA,
it's unrealistic to build and maintain a separate 2FA implementation for each
one. But with this change, you can piggyback on Discourse to take care of all
the 2FA details for you for as many sites as you wish.
To use Discourse as a 2FA provider, you'll need to follow this guide:
https://meta.discourse.org/t/-/32974. It walks you through what you need to
implement on your end/site and how to configure your Discourse instance. Once
you're done, there is only one additional thing you need to do which is to
include `require_2fa=true` in the payload that you send to Discourse.
When Discourse sees `require_2fa=true`, it'll prompt the user to confirm their
2FA using whatever methods they've enabled (TOTP or security keys), and once
they confirm they'll be redirected back to the return URL you've configured and
the payload will contain `confirmed_2fa=true`. If the user has no 2FA methods
enabled however, the payload will not contain `confirmed_2fa`, but it will
contain `no_2fa_methods=true`.
You'll need to be careful to re-run all the security checks and ensure the user
can still access the resource on your site after they return from Discourse.
This is very important because there's nothing that guarantees the user that
will come back from Discourse after they confirm 2FA is the same user that
you've redirected to Discourse.
Internal ticket: t62183.
* FIX: Redirect if Discourse-Xhr-Redirect is present
`handleRedirect` was passed an wrong argument type (a string) instead of
a jqXHR object and missed the fields checked in condition, thus always
evaluating to `false`.
* FIX: Add `errors` field if group update confirmation
An explicit confirmation about the effect of the group update is
required if the default notification level changes. Previously, if the
confirmation was missing the API endpoint failed silently returning
a 200 response code and a `user_count` field. This change ensures that
a proper error code is returned (422), a descriptive error message and
the additional information in the `user_count` field.
This commit also refactors the API endpoint to use the
`Discourse-Xhr-Redirect` header to redirect the user if the group is
no longer visible.
The `blocked onebox domains` setting lets site owners change what sites
are allowed to be oneboxed. When a link is entered into a post,
Discourse checks the domain of the link against that setting and blocks
the onebox if the domain is blocked. But if there's a chain of
redirects, then only the final destination website is checked against
the site setting.
This commit amends that behavior so that every website in the redirect
chain is checked against the site setting, and if anything is blocked
the original link doesn't onebox at all in the post. The
`Discourse-No-Onebox` header is also checked in every response and the
onebox is blocked if the header is set to "1".
Additionally, Discourse will now include the `Discourse-No-Onebox`
header with every response if the site requires login to access content.
This is done to signal to a Discourse instance that it shouldn't attempt
to onebox other Discourse instances if they're login-only. Non-Discourse
websites can also use include that header if they don't wish to have
Discourse onebox their content.
Internal ticket: t59305.
2FA support in Discourse was added and grown gradually over the years: we first
added support for TOTP for logins, then we implemented backup codes, and last
but not least, security keys. 2FA usage was initially limited to logging in,
but it has been expanded and we now require 2FA for risky actions such as
adding a new admin to the site.
As a result of this gradual growth of the 2FA system, technical debt has
accumulated to the point where it has become difficult to require 2FA for more
actions. We now have 5 different 2FA UI implementations and each one has to
support all 3 2FA methods (TOTP, backup codes, and security keys) which makes
it difficult to maintain a consistent UX for these different implementations.
Moreover, there is a lot of repeated logic in the server-side code behind these
5 UI implementations which hinders maintainability even more.
This commit is the first step towards repaying the technical debt: it builds a
system that centralizes as much as possible of the 2FA server-side logic and
UI. The 2 main components of this system are:
1. A dedicated page for 2FA with support for all 3 methods.
2. A reusable server-side class that centralizes the 2FA logic (the
`SecondFactor::AuthManager` class).
From a top-level view, the 2FA flow in this new system looks like this:
1. User initiates an action that requires 2FA;
2. Server is aware that 2FA is required for this action, so it redirects the
user to the 2FA page if the user has a 2FA method, otherwise the action is
performed.
3. User submits the 2FA form on the page;
4. Server validates the 2FA and if it's successful, the action is performed and
the user is redirected to the previous page.
A more technically-detailed explanation/documentation of the new system is
available as a comment at the top of the `lib/second_factor/auth_manager.rb`
file. Please note that the details are not set in stone and will likely change
in the future, so please don't use the system in your plugins yet.
Since this is a new system that needs to be tested, we've decided to migrate
only the 2FA for adding a new admin to the new system at this time (in this
commit). Our plan is to gradually migrate the remaining 2FA implementations to
the new system.
For screenshots of the 2FA page, see PR #15377 on GitHub.
When redirecting to login, we store a destination_url cookie, which the user is then redirected to after login. We never want the user to be redirected to a JSON URL. Instead, we should return a 403 in these situations.
This should also be much less confusing for API consumers - a 403 is a better representation than a 302.
Under some conditions, these varied responses could lead to cache poisoning, hence the 'security' label.
Previously the Rails application would serve JSON data in place of HTML whenever Ember CLI requested an `application.html.erb`-rendered page. This commit removes that logic, and instead parses the HTML out of the standard response. This means that Rails doesn't need to customize its response for Ember CLI.
We have a couple of site setting, `slow_down_crawler_user_agents` and `slow_down_crawler_rate`, that are meant to allow site owners to signal to specific crawlers that they're crawling the site too aggressively and that they should slow down.
When a crawler is added to the `slow_down_crawler_user_agents` setting, Discourse currently adds a `Crawl-delay` directive for that crawler in `/robots.txt`. Unfortunately, many crawlers don't support the `Crawl-delay` directive in `/robots.txt` which leaves the site owners no options if a crawler is crawling the site too aggressively.
This PR replaces the `Crawl-delay` directive with proper rate limiting for crawlers added to the `slow_down_crawler_user_agents` list. On every request made by a non-logged in user, Discourse will check the User Agent string and if it contains one of the values of the `slow_down_crawler_user_agents` list, Discourse will only allow 1 request every N seconds for that User Agent (N is the value of the `slow_down_crawler_rate` setting) and the rest of requests made within the same interval will get a 429 response.
The `slow_down_crawler_user_agents` setting becomes quite dangerous with this PR since it could rate limit lots if not all of anonymous traffic if the setting is not used appropriately. So to protect against this scenario, we've added a couple of new validations to the setting when it's changed:
1) each value added to setting must 3 characters or longer
2) each value cannot be a substring of tokens found in popular browser User Agent. The current list of prohibited values is: apple, windows, linux, ubuntu, gecko, firefox, chrome, safari, applewebkit, webkit, mozilla, macintosh, khtml, intel, osx, os x, iphone, ipad and mac.
