Intent to Ship: NDEFReader makeReadOnly()

François Beaufort 🇫🇷

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Jan 24, 2022, 8:52:26 AM1/24/22

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Summary

The NDEFReader makeReadOnly() method allows web developers to make NFC tags permanently read-only with Web NFC.

Blink component

Blink>NFC

Motivation

Since we’ve shipped Web NFC in Chrome 89, developers have been asking for a way to “lock” NFC tags to prevent malicious users from overwriting their content. See https://github.com/w3c/web-nfc/issues/558
This operation is a one-way process and cannot be reversed. Once an NFC tag has been made read-only, it can't be written anymore.

Existing Web NFC restrictions apply to makeReadOnly(): It is only available to top-level frames and secure browsing contexts (HTTPS only). Origins must first request the "nfc" permission while handling a user gesture (e.g. a button click). To then make the NFC tag read-only, the web page must be visible when the user touches an NFC tag with their device, while still handling a user gesture. The browser uses haptic feedback to indicate a tap. Access to the NFC radio is blocked if the display is off or the device is locked. When a page is placed in the background, receiving and pushing NFC content is suspended.

TAG review

This small addition to the Web NFC API doesn’t seem to qualify for a TAG review. Note that the Security and Privacy section was updated based on last TAG review feedback at https://github.com/w3ctag/design-reviews/issues/461

TAG review status

Not Applicable

Risks

Interoperability and Compatibility

This small addition to the NDEFReader object does not change the overall status of Web NFC interoperability or compatibility.

Signals from other implementations (Gecko, WebKit):

Gecko: No Signal [1]

WebKit: No Signal [1]

Web / Framework developers: Positive https://twitter.com/quicksave2k/status/1465615447806681090

[1] Both Gecko and Webkit are unlikely to object to this feature specifically, but object to the overall Web NFC API as a whole, hence it doesn't make sense to bug them with specific questions on this.

Activation:

This feature can't be polyfilled. It should be fairly trivial for developers to adopt this new feature.

Debuggability

Exposing DevTools debugging support for device-access APIs (Web NFC included) is discussed at https://bugs.chromium.org/p/chromium/issues/detail?id=1142566. For now, affordable NFC tags are required to debug Web NFC.

Is this feature fully tested by web-platform-tests?

Yes. This feature will be fully tested at https://wpt.fyi/results/web-nfc

Requires code in //chrome?

True. The permission prompt text will be updated and current NFC permissions reset so that users clearly know which permission they’re granting to websites.

Tracking bug

https://bugs.chromium.org/p/chromium/issues/detail?id=1275576

Estimated milestones

M100

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5700853265596416

Links to previous Intent discussions

Intent to prototype: https://groups.google.com/a/chromium.org/g/blink-dev/c/iyljeGnIct8/m/tonTVszmCAAJ

Yoav Weiss

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Jan 26, 2022, 4:43:53 PM1/26/22

to blink-dev, François Beaufort

LGTM1

On Monday, January 24, 2022 at 9:52:26 AM UTC+1 François Beaufort wrote:

Contact emails
fbea...@google.com

Explainer
https://github.com/w3c/web-nfc/blob/gh-pages/EXPLAINER.md
https://github.com/w3c/web-nfc/pull/636

Specification
https://w3c.github.io/web-nfc/#dom-ndefreader-makereadonly
https://github.com/w3c/web-nfc/pull/632

Summary
The NDEFReader makeReadOnly() method allows web developers to make NFC tags permanently read-only with Web NFC.

Blink component
Blink>NFC

Motivation
Since we’ve shipped Web NFC in Chrome 89, developers have been asking for a way to “lock” NFC tags to prevent malicious users from overwriting their content. See https://github.com/w3c/web-nfc/issues/558

This seems like a needed use case from the issue comments. Thanks for tackling it!

Mike Taylor

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Jan 26, 2022, 4:44:34 PM1/26/22

to Yoav Weiss, blink-dev, François Beaufort

LGTM2

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mkwst via Chromestatus

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Jan 26, 2022, 4:45:46 PM1/26/22

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LGTM2. I'm happy to see that y'all cooperated well with the security/privacy folks to land on a permission model/string that made sense, and agree with Yoav that there's reasonable evidence of desire for this functionality.

-mike

chrishtr via Chromestatus

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Jan 26, 2022, 4:52:58 PM1/26/22

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LGTM3

chrishtr via Chromestatus

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Jan 26, 2022, 5:04:32 PM1/26/22

to blin...@chromium.org

LGTM3

François Beaufort

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Jan 26, 2022, 5:26:03 PM1/26/22

to blink-dev, chrishtr via Chromestatus

Thank you all!

Note that this intent is for Android only, as Web NFC is available on Android only as well.
This information was captured in the chrome status entry (https://chromestatus.com/feature/5700853265596416).

On Wednesday, January 26, 2022 at 6:04:32 PM UTC+1 chrishtr via Chromestatus wrote:

LGTM3

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