Bug 234180 – [WebAuthn] Allow same-site, cross-origin iframe get()

• Status: RESOLVED
• Resolution: FIXED
• Component: WebKit Misc.

[[e-mail]]

WebAuthn Level 2 specifies a feature policy: https://w3c.github.io/webauthn/#sctn-iframe-guidance, functionality to get credentials from a cross-origin iframe should be enabled if the iframe has the allow="publickey-credentials-get" attribute/value pair.

This patch implements this functionality only for same-site, cross-origin i-frames.

[[e-mail]]

rdar://85161142

[[e-mail]]

Created attachment 446826 [details]
Patch

[Brent Fulgham]

Comment on attachment 446826 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=446826&action=review

I think this patch needs a bit of work before it's ready to land. Please adjust the same-site test, and switch from a boolean to a two-state enum that documents its purpose.

> Source/WebCore/Modules/webauthn/AuthenticatorCoordinator.cpp:184
> +        if (domain != RegistrableDomain(parentDocument->securityOrigin().data()))

You should use "areRegistrableDomainsEqual" from the RegistrableDomains header.

We identify same-site in Document like this:

    // Only prevent cross-site navigations.
    RefPtr targetDocument = targetFrame.document();
    if (targetDocument && (targetDocument->securityOrigin().isSameOriginDomain(SecurityOrigin::create(destinationURL)) || areRegistrableDomainsEqual(targetDocument->url(), destinationURL)))
        return false;

You should probably use something like that to be consistent. It should also handle all the weird cases of data/Blob URLs and so forth properly.

> Source/WebCore/Modules/webauthn/WebAuthenticationUtils.h:55
> +WEBCORE_EXPORT Ref<ArrayBuffer> buildClientDataJson(ClientDataType /*type*/, const BufferSource& challenge, const SecurityOrigin& /*origin*/, const bool crossOrigin);

Instead of this boolean, we should create a two-state enum to represent this state. Something like WebAuthn::CrossOrigin::Yes/No, or WebAuthn::Scope::CrossOrigin/SameOrigin. There are many examples in the sources of this pattern.

[[e-mail]]

Created attachment 447053 [details]
Patch

[Brent Fulgham]

Comment on attachment 447053 [details]
Patch

Looks great -- thank you for making those changes! r=me

[EWS]

Committed r286993 (?): <https://commits.webkit.org/r286993>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 447053 [details].

[WebKit Commit Bot]

Re-opened since this is blocked by bug 234283