1268728 - Remove ability to enable RC4

Status: RESOLVED FIXED

(Core :: Security: PSM, defect)

Description

[Masatoshi Kimura [:emk]]

Attachment: rm_rc4_pref

Chrome 53 will remove a Group Policy setting to re-enable RC4. The expected release date of Chrome 53 is earlier than Firefox 49.

I left some dead code in case we have to backout the change.

Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=2a6f842b701a

Comment 1

[Dana Keeler (she/her) (use needinfo) [:keeler] (on leave)]

Comment on attachment 8746864 [details] [diff] [review]
rm_rc4_pref

Review of attachment 8746864 [details] [diff] [review]:
-----------------------------------------------------------------

This looks good, but I think we should delay this until 50. Also, what's the Chrome bug on removing the group policy?

::: security/manager/ssl/nsNSSComponent.cpp
@@ -1112,5 @@
> -   TLS_RSA_WITH_RC4_128_SHA, true, true }, // deprecated (RSA key exchange, RC4)
> - { "security.ssl3.rsa_rc4_128_md5",
> -   TLS_RSA_WITH_RC4_128_MD5, true, true }, // deprecated (RSA key exchange, RC4, HMAC-MD5)
> -
> - // All the rest are disabled by default

nit: let's keep this comment

Comment 2

[Masatoshi Kimura [:emk]]

Attachment: patch for checkin (wait until 50)

(In reply to David Keeler [:keeler] (use needinfo?) from comment #1)
> This looks good, but I think we should delay this until 50.

OK.

> Also, what's the
> Chrome bug on removing the group policy?

Chrome already embedded the supported version range when they landed RC4-deprecate patch:
https://chromium.googlesource.com/chromium/src.git/+/14b1a53362ffb727e02bdf27e24e93c5f9b2d423%5E!/#F3
Their infrastructure will automatically kill the "RC4Enabled" policy when the Chromium version goes beyond 52. No explicit removal patch is needed.

> ::: security/manager/ssl/nsNSSComponent.cpp
> > - // All the rest are disabled by default
> 
> nit: let's keep this comment

I didn't restore the "by default" part because there is no way to enable unlisted cipher suites.

Comment 3

[Masatoshi Kimura [:emk]]

Attachment: rebased to tip

I stopped to remove test_weak_crypto.js because bug 1113974 will reuse it very soon.

Comment 4

[Masatoshi Kimura [:emk]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=7ff7fb82704e

Comment 5

[Masatoshi Kimura [:emk]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/7afaa7546076f20c447c87e352a9953101977647
Bug 1268728 - Remove ability to enable RC4. r=keeler

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/7afaa7546076

Comment 7

[Kohei Yoshino [:kohei]]

Posted the site compatibility doc, since I've seen some users on SUMO who are confused with this change: https://www.fxsitecompat.com/en-CA/docs/2016/rc4-support-has-been-completely-removed/

Comment 8

[Eric Shepherd [:sheppy]]

Noted on Firefox 50 for developers.