tl;dr: we're planning to switch the cipher suites and TLS versions supported by Sync and other background services in Firefox for Android.
If you self-host and sync with Firefox for Android, maintain a third-party Sync client, or are very interested in cipher suites, read on. *History* We used to support Android versions back to API 5. This left some significant gaps in our coverage; combined with the LB support we had at the time, and some code limitations, we ended up with a less-than-ideal set of cipher suites and protocols, falling back on failure. *Modern context* There are a bunch of recent and not-so-recent attacks that we'd like to completely avoid by requiring strong cipher suites and protocols. We're still limited by older versions of Android, but we can still do better than we do now. Additionally, some devices ship a restricted Java SSL configuration, so we can actually cause crashes on those devices. I hope that this change will fix those problems. This is also a step towards tightening up server configurations, so the sooner we get this into deployed clients, the better. *Proposal* On modern Android, we plan to support only TLSv1.2 (preferred) and TLSv1.1. On older Android, we'll support only TLSv1, *eliminating support for SSLv3*. For cipher suites we'll support only the best available at each level: Gingerbread: TLS_DHE_RSA_WITH_AES_256_CBC_SHA Honeycomb onwards: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 4.4W onwards: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA As I understand it, these are a subset (with the exception of Gingerbread's, perhaps) of the cipher suites that we would like to support in production, so there should be no issues with matching support in recent desktop versions or on iOS. These selections will apply to FHR and other background services, too, so I'll be vetting those as best I can. *Testing* This proposal needs thorough testing as well as feedback, so — like all plans — it's subject to change. If these supported cipher suites or protocols stand out as bad choices to you, please let me know. I hope to land these changes in the next week or two, uplifting to Aurora and Beta as appropriate, with eventual release in 39 or 40. Thanks! -Richard
_______________________________________________ Sync-dev mailing list Sync-dev@mozilla.org https://mail.mozilla.org/listinfo/sync-dev
