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

Change Script Enforcement Mechanism to use flags #579

Draft
wants to merge 1 commit into
base: main
Choose a base branch
from
+42 −42
Draft

Change Script Enforcement Mechanism to use flags #579

Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
84 changes: 42 additions & 42 deletions spec/index.bs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -127,14 +127,14 @@ spec:ECMA-262; urlPrefix: https://tc39.github.io/ecma262/
type:dfn; text:current realm record; url: current-realm
spec: HTML; urlPrefix: https://html.spec.whatwg.org/
type: dfn; text: prepare the script element; url: prepare-the-script-element
type: dfn; text: The text insertion mode; url: parsing-main-incdata
type: dfn; text: reentrant invocation of the parser; url: nestedParsing
type: dfn; text: get the text steps; url: get-the-text-steps
type: dfn; text: set the inner text steps; url: set-the-inner-text-steps
type: dfn; text: src; url: attr-script-src
type: dfn; text: HTML element post-connection steps; url: html-element-post-connection-steps
spec:DOM; urlPrefix: https://dom.spec.whatwg.org/
type: dfn; text: get text content; url: get-text-content
type: dfn; text: set text content; url: set-text-content
type: dfn; text: post-connection steps; url: concept-node-post-connection-ext
</pre>

<pre class="link-defaults">
Expand Down Expand Up @@ -1067,20 +1067,6 @@ Given a {{TrustedType}} type (|expectedType|), a [=realm/global object=] (|globa
1. Return a new instance of an interface with a type
name |trustedTypeName|, with its associated data value set to |dataString|.

## <dfn abstract-op>Prepare the script text</dfn> ## {#prepare-script-text}

Given an {{HTMLScriptElement}} (|script|), this algorithm performs the following steps:

1. If |script|'s [=script text=] value is not equal to its [=child text content=],
set |script|'s [=script text=] to the result of executing [$Get Trusted Type compliant string$], with the following arguments:
* {{TrustedScriptURL}} as |expectedType|,
* |script|'s {{Document}}'s [=relevant global object=] as |global|,
* |script|'s [=child text content=] attribute value,
* `HTMLScriptElement text` as |sink|,
* `'script'` as |sinkGroup|.

If the algorithm threw an error, rethrow the error.

## Get Trusted Types-compliant attribute value ## {#validate-attribute-mutation}
To <dfn abstract-op export>get Trusted Types-compliant attribute value</dfn> on {{Attr}} |attribute| with {{Element}} |element| and {{TrustedType}} or a string |newValue|, perform the following steps:

Expand Down Expand Up @@ -1171,12 +1157,17 @@ partial interface HTMLScriptElement {

#### Slots with trusted values #### {#slots-with-trusted-values}

This document modifies {{HTMLScriptElement}}s. Each script has:
An {{HTMLScriptElement}} and {{SVGScriptElement}} have:

: an associated boolean <dfn export for="HTMLScriptElement,SVGScriptElement">is trusted</dfn>.
:: A boolean indicating whether a script element is considered trustworthy for execution.
Initially true.

Note: This boolean is initially true so that parsed scripts are trusted.

: an associated string <dfn export for="HTMLScriptElement">script text</dfn>.
:: A string, containing the body of the script to execute that was set
through a compliant sink. Equivalent to script's
[=child text content=]. Initially an empty string.
: an associated boolean <dfn export for="HTMLScriptElement,SVGScriptElement">changed by trusted sink</dfn>.
:: A boolean indicating whether a script element has been modified by a trusted sink.
Initially false.

#### The {{HTMLScriptElement/innerText}} IDL attribute #### {#the-innerText-idl-attribute}

Expand All @@ -1185,7 +1176,7 @@ The {{HTMLScriptElement/innerText}} setter steps are:
1. Let |value| be the result of calling [$Get Trusted Type compliant string$] with
{{TrustedScript}}, [=this=]'s [=relevant global object=], the given value, `HTMLScriptElement innerText`, and
`script`.
1. Set [=this=]'s [=script text=] value to |value|.
1. Set [=this=]'s [=HTMLScriptElement/changed by trusted sink=] to true.
1. Run [=set the inner text steps=] with [=this=] and |value|.

The {{HTMLScriptElement/innerText}} getter steps are:
Expand All @@ -1200,7 +1191,7 @@ empty string instead, and then do as described below:
1. Let |value| be the result of calling [$Get Trusted Type compliant string$] with
{{TrustedScript}}, [=this=]'s [=relevant global object=], the given value, `HTMLScriptElement textContent`, and
`script`.
1. Set [=this=]'s [=script text=] value to |value|.
1. Set [=this=]'s [=HTMLScriptElement/changed by trusted sink=] to true.
1. Run [=set text content=] with [=this=] and |value|.

The {{HTMLScriptElement/textContent}} getter steps are:
Expand All @@ -1214,7 +1205,7 @@ Update the {{HTMLScriptElement/text}} setter steps algorithm as follows.
1. <ins>Let |value| be the result of calling [$Get Trusted Type compliant string$] with
{{TrustedScript}}, [=this=]'s [=relevant global object=], the given value, `HTMLScriptElement text`, and
`script`.</ins>
1. <ins>Set [=this=]'s [=script text=] value to the given value.</ins>
1. Set [=this=]'s [=HTMLScriptElement/changed by trusted sink=] to true.
1. [=String replace all=] with the given value within [=this=].


Expand All @@ -1227,29 +1218,27 @@ The {{HTMLScriptElement/src}} setter steps are:
`script`.</ins>
1. <ins>Set [=this=]'s [=src=] content attribute to |value|.</ins>

#### Setting slot values from parser #### {#setting-slot-values-from-parser}
#### Script children changed steps #### {#script-children-changed-steps}

This document modifies the HTML parser to set the [=script text=] value when the script is created.
This document modifies the [=children changed steps=] for {{HTMLScriptElement}} as follows:

Modify the [=The text insertion mode=] algorithm as follows:
1. <ins>Set [=this=]'s [=HTMLScriptElement/is trusted=] to false.</ins>

<dl class="switch">
<dt id="scriptEndTag">An end tag whose tag name is "script"</dt>
<dd>
<p>...</p>
1. <ins>If [=this=]'s [=HTMLScriptElement/changed by trusted sink=] is true, set [=this=]'s [=HTMLScriptElement/is trusted=] to true.</ins>

<ins><p>Set <var>script</var>'s [=script text=] value to its [=child text content=].</p></ins>
1. <ins>Set [=this=]'s [=HTMLScriptElement/changed by trusted sink=] to false.</ins>

<p>If the <span>active speculative HTML parser</span> is null, then <span>prepare the script
element</span> <var>script</var>. This might cause some script to execute, which might cause
<span data-x="dom-document-write">new characters to be inserted into the tokenizer</span>, and
might cause the tokenizer to output more tokens, resulting in a [=reentrant invocation of the parser=].</p>
1. Run the {{HTMLScriptElement|script}} [=HTML element post-connection steps=], given [=this=].

<p>...</p>
</dd>
</dl>
Issue: This relies on the children changed steps never being called by the parser.

Issue: The above algorithm doesn't account for the case when the script element's content is changed mid-parse. Implementors should ensure they protect against this case. See [https://github.com/w3c/trusted-types/issues/507](https://github.com/w3c/trusted-types/issues/507).
This document modifies the [=children changed steps=] for {{SVGScriptElement}} as follows:

1. Set [=this=]'s [=SVGScriptElement/is trusted=] to false.

1. Run the {{SVGScriptElement|script}} [=post-connection steps=], given [=this=].
Copy link
Member Author

Choose a reason for hiding this comment

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

Does SVG even have this?


Issue: This relies on the children changed steps never being called by the parser.

#### Slot value verification #### {#slot-value-verification}

Expand All @@ -1270,11 +1259,22 @@ The first few steps of the [=prepare the script element=] algorithm are modified
<p class=note>This is done so that if a parser-inserted <code id=script-processing-model:the-script-element-28><a href=https://html.spec.whatwg.org/#the-script-element>script</a></code> element fails to
run when the parser tries to run it, but it is later executed after a script dynamically
updates it, it will execute in an async fashion even if the <code id=script-processing-model:attr-script-async-5><a href=https://html.spec.whatwg.org/#attr-script-async>async</a></code> attribute isn't set.</p>
<li><ins><p>Execute the [$Prepare the script text$] algorithm on <var>el</var>. If that algorithm threw an error, then return.</p></ins></li>
<li><p>Let <var ignore="">source text</var> be <var>el</var>'s <del><a id=script-processing-model:child-text-content href=https://dom.spec.whatwg.org/#concept-child-text-content data-x-internal=child-text-content>child text content</a>.</del> <ins>[=script text=] value.</ins>

<li><p>Let <var>source text</var> be <var>el</var>'s <a id=script-processing-model:child-text-content href=https://dom.spec.whatwg.org/#concept-child-text-content data-x-internal=child-text-content>child text content</a>.

<li><ins>
<p>If <var>el</var>'s [=HTMLScriptElement/is trusted=] is false:
<ol>
<li><p>Set <var>source text</var> to the result of executing [$Get Trusted Type compliant string$], with
{{TrustedScript}}, <var>el</var>'s [=relevant global object=], <var>source text</var>, `'HTMLScriptElement text'`,
and `'script'`.
<p>If that algorithm threw an error, then return.
</ol></ins>
<li>...
</ol>

Issue: There's no proper definition for the processing of SVG script elements. However, you should apply a similar change to the processing of {{SVGScriptElement}}s.

## Integration with DOM ## {#integration-with-dom}

Note: See [https://github.com/whatwg/dom/pull/1268](https://github.com/whatwg/dom/pull/1268) which upstreams this integration.
Expand Down
Loading