1724072 - only allow 3DES ciphersuites when deprecated TLS is enabled

Status: RESOLVED FIXED

(Core :: Security: PSM, enhancement, P1)

Description

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

Chrome has removed 3DES completely: https://www.chromestatus.com/feature/6678134168485888, but we're still seeing some uses of it: https://mzl.la/3CeLTy5 (bucket 66), albeit a very small percentage. Our assumption is that this is either due to old devices that can't be upgraded, and hence probably use TLS 1.0, or servers that bafflingly choose 3DES when there are other, better, ciphersuites in common. Only allowing 3DES to be enabled when deprecated versions of TLS are enabled should protect users against the latter case (where 3DES is unnecessary) while allowing them to use it in the former case (where it may be necessary).

Comment 1

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

Attachment: Bug 1724072 - allow enabling 3DES only when deprecated versions of TLS are enabled r?rmf

Chrome has removed 3DES completely[0], but we're still seeing some uses of it
in telemetry. Our assumption is that this is either due to old devices that
can't be upgraded, and hence probably use TLS 1.0, or servers that bafflingly
choose 3DES when there are other, better, ciphersuites in common.
This patch allows 3DES to only be enabled when deprecated versions of TLS are
enabled. This should protect users against the latter case (where 3DES is
unnecessary) while allowing them to use it in the former case (where it may be
necessary).

NB: The only 3DES ciphersuite gecko makes possible to enable is
TLS_RSA_WITH_3DES_EDE_CBC_SHA. This patch also changes the preference
corresponding to this ciphersuite from "security.ssl3.rsa_des_ede3_sha" to
"security.ssl3.deprecated.rsa_des_ede3_sha".

[0] https://www.chromestatus.com/feature/6678134168485888

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4f793a75cd93
allow enabling 3DES only when deprecated versions of TLS are enabled r=rmf

Comment 3

[Narcis Beleuzu [:NarcisB]]

Backed out for geckoview failures

Backout link: https://hg.mozilla.org/integration/autoland/rev/9a90492e53a9f81ed7551dc05a58ac8454ec23e1
Log link: https://treeherder.mozilla.org/logviewer?job_id=347982289&repo=autoland&lineNumber=7407

Comment 4

[Narcis Beleuzu [:NarcisB]]

Please also check :

1. mochitest failures on test_content_javascript_loads.html -> https://treeherder.mozilla.org/logviewer?job_id=347982603&repo=autoland&lineNumber=1875
2. mda failures on test_cloneElementVisually_ended_video.html -> https://treeherder.mozilla.org/logviewer?job_id=347982655&repo=autoland&lineNumber=2420

Comment 5

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

Attachment: Bug 1724072 - replace RC4 capabilities in ssltunnel with 3DES r?rmf

This patch updates ssltunnel to have a configuration where it only uses a 3DES
ciphersuite, rather than RC4 ciphersuites. This has to be done in stages
because otherwise android tests will fail, because their hostutils doesn't
actually use what's in-tree, and has to be updated separately.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/303b3bd2213c
replace RC4 capabilities in ssltunnel with 3DES r=rmf

Comment 7

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/303b3bd2213c

Comment 8

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

Attachment: Bug 1724072 - update android hostutils due to ssltunnel changes r?gbrown

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/76accb62cb07
update android hostutils due to ssltunnel changes r=gbrown

Comment 10

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/76accb62cb07

Comment 11

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/9e127bea2a18

Comment 12

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

Release Note Request (optional, but appreciated)
[Why is this notable]: potential compatibility concern
[Affects Firefox for Android]: yes
[Suggested wording]: TLS ciphersuites that use 3DES have been disabled. Such ciphersuites can only be enabled when deprecated versions of TLS are also enabled.
[Links (documentation, blog post, etc)]:

Comment 14

[Pascal Chevrel:pascalc]

Note added to 93 beta release notes