Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fixes #151 - Define a "ch-ua-high-entropy-values" permission policy #373

Merged
merged 2 commits into from
Dec 24, 2024
Merged

Fixes #151 - Define a "ch-ua-high-entropy-values" permission policy #373

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
7193f72
Fixes #151 - Define a "ch-ua-high-entropy-values" permission policy
miketaylr Dec 20, 2024
2760d9a
editorial tweak
miketaylr Dec 20, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
43 changes: 29 additions & 14 deletions index.bs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -338,7 +338,7 @@ brand of the browser to the user. These messages often also include the platform
order to make sure the user knows which device is in question.

Since such messaging doesn't require any server-side adaptation, it's better for this case to use
the `userAgentData.getHighEntropyData()` method in order to retrieve the required information.
the `userAgentData.getHighEntropyValues()` method in order to retrieve the required information.
yoavweiss marked this conversation as resolved.
Show resolved Hide resolved

### Download of appropriate binary executables ### {#binary-executable-downloads}
Some sites are used to download binary executables of native applications, and need to be able to
Expand Down Expand Up @@ -373,7 +373,7 @@ the lower entropy values available through `Sec-CH-UA` for logging purposes, or
higher-entropy hints. The latter doesn't seem like something services should do just for forensic
purposes. On the other hand, when specific issues are encountered, it may make sense for those
services to opt-in to receive more details on the user agent, or use the
`userAgentData.getHighEntropyData()` API for that purpose.
`userAgentData.getHighEntropyValues()` API for that purpose.

### Fingerprinting ### {#fingerprinting-use-case}

Expand Down Expand Up @@ -971,21 +971,25 @@ On getting, the {{NavigatorUAData/platform}} attribute must return the [=user ag

<h4 id="getHighEntropyValues"><code>getHighEntropyValues</code> method</h4>

The <dfn method for="NavigatorUA"><code>getHighEntropyValues(|hints|)</code></dfn> method MUST run these steps:
The <dfn method for="NavigatorUA"><code>getHighEntropyValues(|hints|)</code></dfn> method MUST run
these steps:

1. Let |p| be a [=a new promise=] created in the [=current realm=].

2. If the [=user agent=] decides one or more values in |hints| should not be returned, then [=reject=] and return |p| with a "{{NotAllowedError}}".
Copy link
Collaborator Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This has never been implemented, FWIW (at least not in Chromium).

1. Let |uaData| be a new {{UADataValues}}.

ISSUE(wicg/ua-client-hints): We can improve upon when and why a UA decides to refuse a hint once [Issue #151](https://github.com/WICG/ua-client-hints/issues/151) is resolved.
1. set |uaData|["{{UADataValues/brands}}"] to [=this=]'s [=relevant global object=]'s
[=WindowOrWorkerGlobalScope/brands frozen array=].

3. Otherwise, run the following steps [=in parallel=]:
1. set |uaData|["{{UADataValues/mobile}}"] to the [=user agent=]'s [=user agent/mobileness=].

1. set |uaData|["{{UADataValues/platform}}"] to the [=user agent=]'s [=user agent/platform brand=].

1. If [=this=]'s [=relevant global object=]'s [=associated Document=] is not [=allowed to use=] the
[=ch-ua-high-entropy-values=] feature, resolve |p| with |uaData|.

1. Otherwise, run the following steps [=in parallel=]:

1. Let |uaData| be a new {{UADataValues}}.
1. set |uaData|["{{UADataValues/brands}}"] to [=this=]'s [=relevant global object=]'s
[=WindowOrWorkerGlobalScope/brands frozen array=].
1. set |uaData|["{{UADataValues/mobile}}"] to the [=user agent=]'s [=user agent/mobileness=].
1. set |uaData|["{{UADataValues/platform}}"] to the [=user agent=]'s [=user agent/platform brand=].
1. If |hints| [=list/contains=] "architecture", set |uaData|["{{UADataValues/architecture}}"] to
the [=user agent=]'s [=user agent/platform architecture=].
1. If |hints| [=list/contains=] "bitness", set |uaData|["{{UADataValues/bitness}}"] to
Expand All @@ -1012,12 +1016,23 @@ The <dfn method for="NavigatorUA"><code>toJSON()</code></dfn> method MUST run th

1. Let |uaLowEntropyData| be a new {{UALowEntropyJSON}}

1. set |uaLowEntropyData|["{{UALowEntropyJSON/brands}}"] to [=this=]'s [=relevant global object=]'s [=WindowOrWorkerGlobalScope/brands frozen array=].
1. set |uaLowEntropyData|["{{UALowEntropyJSON/mobile}}"] to the [=user agent=]'s [=user agent/mobileness=].
1. set |uaLowEntropyData|["{{UALowEntropyJSON/platform}}"] to the [=user agent=]'s [=user agent/platform brand=].
1. Set |uaLowEntropyData|["{{UALowEntropyJSON/brands}}"] to [=this=]'s [=relevant global object=]'s [=WindowOrWorkerGlobalScope/brands frozen array=].
1. Set |uaLowEntropyData|["{{UALowEntropyJSON/mobile}}"] to the [=user agent=]'s [=user agent/mobileness=].
1. Set |uaLowEntropyData|["{{UALowEntropyJSON/platform}}"] to the [=user agent=]'s [=user agent/platform brand=].

1. Return |uaLowEntropyData|

Permissions-Policy Integration {#permisisons-policy-integration}
==============================

This specification defines a [=policy-controlled feature=] identified by the string
"<code><dfn export>ch-ua-high-entropy-values</dfn></code>" which has a [=default allowlist=] of
`'*'`. This determines if a given document is allowed to return [=high-entropy client hint=] values
via the {{NavigatorUAData/getHighEntropyValues(hints)/hints|getHighEntropyValues()}} API.

Note: If a given document is not allowed to use the `"ch-ua-high-entropy-values"` feature, the
`getHighEntropyValues()` API will continue to return the low-entropy values for convenience.

Security and Privacy Considerations {#security-privacy}
===================================

Expand Down
Loading