967923 - Randomize timestamps in TLS handshake

Status: RESOLVED DUPLICATE of bug 937976

(NSS :: Libraries, defect)

Description

[Mike Perry]

Attachment: 0001-Disable-timestamps-in-TLS-handshake.patch

In Tor Browser and in Tor, we have decided to randomize the TLS timestamp field rather than submit the current machine time, to avoid clock drift fingerprinting. It turns out that OpenSSL merged our patch for this in 1.0.1f. Here's a link to that discussion:
https://www.ietf.org/mail-archive/web/tls/current/msg09861.html

The timestamp field is used only as an additional entropy source in TLS, and having it not reflect the actual current time does not affect operation of the handshake. In fact, Firefox actually had a long-standing bug where the current machine uptime was reported in this field instead of the current time, which as far as I know, persisted from the Netscape days up until Firefox 3.5. See Bug 405625.

Attached is the patch for NSS, against FF24ESR.

Comment 1

[Brian Smith (:briansmith, :bsmith, use NEEDINFO?)]

Already fixed and already shipping to users in Fx26 and Chrome 30-something.