1816064 - Implement the random seed generating mechanism for randomizing browser fingerprinting

Status: RESOLVED FIXED

(Core :: Privacy: Anti-Tracking, task)

Description

[Tim Huang[:timhuang]]

To support adding random noises to the browser fingerprinting, we need to have a way to generate the random seed for the noises. The random seed should be consistent within the browsing session to prevent fingerprinters from canceling the noises by inspecting multiple samples of the browser fingerprint. In addition, we should generate different random seeds under distinct top-level domains to prevent third-party tracking by using the browser fingerprint.

We need to generate a new seed when the browsing session ends. It means we need to reset the seed when

• The browser restarts
• The private browsing session is ended
• We can consider resetting the random seed daily to protect long-live sessions.

The random seed can be kept in the CookieJarSettings because it's tied to the top-level domain once created and remain consistent until the tab closes.

Comment 1

[Tim Huang[:timhuang]]

Attachment: Bug 1816064 - Part 1: Implement the session key for generating the random noise key for fingerprinting randomization. r?tjr

This patch implements the session key that will be used to generate the
random noise for fingerprinting randomization. The session keys will
live in the nsRFPService in the parent process only. nsRFPServices holds
two session keys for normal and private windows respectively. The
lifetime of normal sessino key is tie to the Firefox; it resets with
Firefox restarts. For private session key, it resets when the private
session ends. i.e. all private windows are closed.

Comment 2

[Tim Huang[:timhuang]]

Attachment: Bug 1816064 - Part 2: Implement the fingerprinting randomization key to cookieJarSettings. r?tjr!,pbz!

This patch adds a fingerprintingRandomizationKey to the
nsICookieJarSettings. The random key will be generated when loading a
top-level http channel and set to the cookieJarSettings. The key will
propagate to the top-level documant and all sub-documents with the
cookieJarSettings. Accessing the fingerprintingRandomizationKey will
return an error if the fingerprinting randomization is disabled.

Depends on D170603

Comment 3

[Tim Huang[:timhuang]]

Attachment: Bug 1816064 - Part 3: Add tests for fingerprinting randomization key generation. r?tjr

Depends on D170604

Comment 4

[Tim Huang[:timhuang]]

Attachment: Bug 1816064 - Part 4: Don't generate randomization key if unnecessary. r?tjr

We don't need to generate the randomization key if fingerprinting
protection is disabled. This could happen if fingerprinting protection
is disabled or exempted from normal windows. In these cases, we don't
need to generate the key, which can save us the cost of generating the
key.

Depends on D170605

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/68074ac5a154
Part 1: Implement the session key for generating the random noise key for fingerprinting randomization. r=tjr
https://hg.mozilla.org/integration/autoland/rev/f605a7ddf950
Part 2: Implement the fingerprinting randomization key to cookieJarSettings. r=tjr,pbz
https://hg.mozilla.org/integration/autoland/rev/42dd4e8f265f
Part 3: Add tests for fingerprinting randomization key generation. r=tjr
https://hg.mozilla.org/integration/autoland/rev/5cbc00f75b56
Part 4: Don't generate randomization key if unnecessary. r=tjr

Comment 6

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/68074ac5a154
https://hg.mozilla.org/mozilla-central/rev/f605a7ddf950
https://hg.mozilla.org/mozilla-central/rev/42dd4e8f265f
https://hg.mozilla.org/mozilla-central/rev/5cbc00f75b56