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author | Jacob Bednarz <jacob.bednarz@gmail.com> | 2019-07-11 08:33:16 +1000 |
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committer | Jeremy Daer <jeremydaer@gmail.com> | 2019-07-10 15:33:15 -0700 |
commit | bf19b8774e20e98f7fdcd3ac82ee17f9adee22d8 (patch) | |
tree | faad52b4d0844b3eb6ad90c414076bddafd0c972 /actionpack/lib/action_controller/metal | |
parent | 2fa21fe736b08b5fbff173d518dacb5dbde11936 (diff) | |
download | rails-bf19b8774e20e98f7fdcd3ac82ee17f9adee22d8.tar.gz rails-bf19b8774e20e98f7fdcd3ac82ee17f9adee22d8.tar.bz2 rails-bf19b8774e20e98f7fdcd3ac82ee17f9adee22d8.zip |
Adds support for configuring HTTP Feature Policy (#33439)
A HTTP feature policy is Yet Another HTTP header for instructing the
browser about which features the application intends to make use of and
to lock down access to others. This is a new security mechanism that
ensures that should an application become compromised or a third party
attempts an unexpected action, the browser will override it and maintain
the intended UX.
WICG specification: https://wicg.github.io/feature-policy/
The end result is a HTTP header that looks like the following:
```
Feature-Policy: geolocation 'none'; autoplay https://example.com
```
This will prevent the browser from using geolocation and only allow
autoplay on `https://example.com`. Full feature list can be found over
in the WICG repository[1].
As of today Chrome and Safari have public support[2] for this
functionality with Firefox working on support[3] and Edge still pending
acceptance of the suggestion[4].
#### Examples
Using an initializer
```rb
# config/initializers/feature_policy.rb
Rails.application.config.feature_policy do |f|
f.geolocation :none
f.camera :none
f.payment "https://secure.example.com"
f.fullscreen :self
end
```
In a controller
```rb
class SampleController < ApplicationController
def index
feature_policy do |f|
f.geolocation "https://example.com"
end
end
end
```
Some of you might realise that the HTTP feature policy looks pretty
close to that of a Content Security Policy; and you're right. So much so
that I used the Content Security Policy DSL from #31162 as the starting
point for this change.
This change *doesn't* introduce support for defining a feature policy on
an iframe and this has been intentionally done to split the HTTP header
and the HTML element (`iframe`) support. If this is successful, I'll
look to add that on it's own.
Full documentation on HTTP feature policies can be found at
https://wicg.github.io/feature-policy/. Google have also published[5] a
great in-depth write up of this functionality.
[1]: https://github.com/WICG/feature-policy/blob/master/features.md
[2]: https://www.chromestatus.com/feature/5694225681219584
[3]: https://bugzilla.mozilla.org/show_bug.cgi?id=1390801
[4]: https://wpdev.uservoice.com/forums/257854-microsoft-edge-developer/suggestions/33507907-support-feature-policy
[5]: https://developers.google.com/web/updates/2018/06/feature-policy
Diffstat (limited to 'actionpack/lib/action_controller/metal')
-rw-r--r-- | actionpack/lib/action_controller/metal/feature_policy.rb | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/metal/feature_policy.rb b/actionpack/lib/action_controller/metal/feature_policy.rb new file mode 100644 index 0000000000..eecca20dda --- /dev/null +++ b/actionpack/lib/action_controller/metal/feature_policy.rb @@ -0,0 +1,46 @@ +# frozen_string_literal: true + +module ActionController #:nodoc: + # HTTP Feature Policy is a web standard for defining a mechanism to + # allow and deny the use of browser features in its own context, and + # in content within any <iframe> elements in the document. + # + # Full details of HTTP Feature Policy specification and guidelines can + # be found at MDN: + # + # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Feature-Policy + # + # Examples of usage: + # + # # Global policy + # Rails.application.config.feature_policy do |f| + # f.camera :none + # f.gyroscope :none + # f.microphone :none + # f.usb :none + # f.fullscreen :self + # f.payment :self, "https://secure-example.com" + # end + # + # # Controller level policy + # class PagesController < ApplicationController + # feature_policy do |p| + # p.geolocation "https://example.com" + # end + # end + module FeaturePolicy + extend ActiveSupport::Concern + + module ClassMethods + def feature_policy(**options, &block) + before_action(options) do + if block_given? + policy = request.feature_policy.clone + yield policy + request.feature_policy = policy + end + end + end + end + end +end |