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[Fizz] escape <style> textContent as css #28870

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merged 1 commit into from
Apr 19, 2024
Merged

[Fizz] escape <style> textContent as css #28870

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24 changes: 22 additions & 2 deletions packages/react-dom-bindings/src/server/ReactFizzConfigDOM.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2669,6 +2669,26 @@ function pushStyle(
}
}

/**
* This escaping function is designed to work with style tag textContent only.
*
* While untrusted style content should be made safe before using this api it will
* ensure that the style cannot be early terminated or never terminated state
*/
function escapeStyleTextContent(styleText: string) {
if (__DEV__) {
checkHtmlStringCoercion(styleText);
}
return ('' + styleText).replace(styleRegex, styleReplacer);
}
const styleRegex = /(<\/|<)(s)(tyle)/gi;
const styleReplacer = (
match: string,
prefix: string,
s: string,
suffix: string,
) => `${prefix}${s === 's' ? '\\73 ' : '\\53 '}${suffix}`;
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should there be the spaces here? Not exactly sure how that escaping works. '\\73 '

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Yes. That’s how the end of the escape sequence is encoded in CSS. It should be exactly one.


function pushStyleImpl(
target: Array<Chunk | PrecomputedChunk>,
props: Object,
Expand Down Expand Up @@ -2710,7 +2730,7 @@ function pushStyleImpl(
child !== undefined
) {
// eslint-disable-next-line react-internal/safe-string-coercion
target.push(stringToChunk(escapeTextForBrowser('' + child)));
target.push(stringToChunk(escapeStyleTextContent(child)));
}
pushInnerHTML(target, innerHTML, children);
target.push(endChunkForTag('style'));
Expand Down Expand Up @@ -2752,7 +2772,7 @@ function pushStyleContents(
child !== undefined
) {
// eslint-disable-next-line react-internal/safe-string-coercion
target.push(stringToChunk(escapeTextForBrowser('' + child)));
target.push(stringToChunk(escapeStyleTextContent(child)));
}
pushInnerHTML(target, innerHTML, children);
return;
Expand Down
50 changes: 50 additions & 0 deletions packages/react-dom/src/__tests__/ReactDOMFizzServer-test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4256,6 +4256,56 @@ describe('ReactDOMFizzServer', () => {
});
});

describe('<style> textContent escaping', () => {
it('the "S" in "</?[Ss]style" strings are replaced with unicode escaped lowercase s or S depending on case, preserving case sensitivity of nearby characters', async () => {
await act(() => {
const {pipe} = renderToPipeableStream(
<style>{`
.foo::after {
content: 'sSsS</style></Style></StYlE><style><Style>sSsS'
}
body {
background-color: blue;
}
`}</style>,
);
pipe(writable);
});
expect(window.getComputedStyle(document.body).backgroundColor).toMatch(
'blue',
);
});

it('the "S" in "</?[Ss]style" strings are replaced with unicode escaped lowercase s or S depending on case, preserving case sensitivity of nearby characters inside hoistable style tags', async () => {
await act(() => {
const {pipe} = renderToPipeableStream(
<>
<style href="foo" precedence="default">{`
.foo::after {
content: 'sSsS</style></Style></StYlE><style><Style>sSsS'
}
body {
background-color: blue;
}
`}</style>
<style href="bar" precedence="default">{`
.foo::after {
content: 'sSsS</style></Style></StYlE><style><Style>sSsS'
}
body {
background-color: red;
}
`}</style>
</>,
);
pipe(writable);
});
expect(window.getComputedStyle(document.body).backgroundColor).toMatch(
'red',
);
});
});

// @gate enableFizzExternalRuntime
it('supports option to load runtime as an external script', async () => {
await act(() => {
Expand Down