Bug 216755 – [WebCrypto] Support Elliptic Curve P-521 on Mac

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Jonas Finnemann Jensen]

WebKit on Mac built with CommonCrypto does not support Elliptic Curve P-521 in WebCrypto for ECDSA and ECDH.
The code [2] only allows P-256 or P-384.

Lack of support for P-521 is noted in the "Update on Web Cryptography" blog post [1], but the bug 169231 was resolved without
addressing support for P-521 on Mac with according to [Bug 169231 Comment 4][3] because of missing support in CommonCrypto.

Leaving out P-521 support might be reasonable, I'm not an expert on the strength of these primitives.
But I imagine that supporting it would be nice for compatibility with Firefox and Chrome, both of which support P-521.

Feel free to reopen bug 169231, and close this as a duplicate :)
(sorry, for the noise, but this seems like a compatibility issue worth tracking)

[1]: https://webkit.org/blog/7790/update-on-web-cryptography/
[2]: https://trac.webkit.org/browser/webkit/trunk/Source/WebCore/crypto/mac/CryptoKeyECMac.cpp?rev=239692#L105
[3]: https://bugs.webkit.org/show_bug.cgi?id=169231#c4

[Radar WebKit Bug Importer]

<rdar://problem/69667220>

[Chris Dumez]

Created attachment 432998 [details]
WIP Patch

[Chris Dumez]

Created attachment 432999 [details]
WIP Patch

[Chris Dumez]

A couple of tests are crashing in signECDSA(), I will need to figure out why.

[Chris Dumez]

Created attachment 433036 [details]
WIP Patch

[Chris Dumez]

Created attachment 433037 [details]
Patch

[Chris Dumez]

Created attachment 433043 [details]
Patch

[Chris Dumez]

Created attachment 433065 [details]
Patch

[Alex Christensen]

Comment on attachment 433065 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=433065&action=review

> Source/WebCore/crypto/mac/CryptoKeyECMac.cpp:62
> +        return size == 133;

It would be nice if these were given names instead of just magic numbers.  Or they could be calculated from constexpr expressions.

> Source/WebCore/crypto/mac/CryptoKeyECMac.cpp:78
> +        return size == 66;

ditto.

[Chris Dumez]

Created attachment 433090 [details]
Patch

[Chris Dumez]

(In reply to Alex Christensen from comment #9)
> Comment on attachment 433065 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=433065&action=review
> 
> > Source/WebCore/crypto/mac/CryptoKeyECMac.cpp:62
> > +        return size == 133;
> 
> It would be nice if these were given names instead of just magic numbers. 
> Or they could be calculated from constexpr expressions.
> 
> > Source/WebCore/crypto/mac/CryptoKeyECMac.cpp:78
> > +        return size == 66;
> 
> ditto.

Fixed. Now computed using constexpr functions instead of hardcoded values.

[EWS]

Committed r279688 (239493@main): <https://commits.webkit.org/239493@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 433090 [details].