"::" entry in notracking hosts file blocks URLs containing "::"; parse notracking list

[Mathnerd314]

Prerequisites

• I verified that this is not a filter issue
  • Filter issues MUST be reported at filter issue tracker
• This is not a support issue or a question
  • Support issues and questions are handled at /r/uBlockOrigin
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue
  • Your issue may already be reported.
• I tried to reproduce the issue when...
  • uBlock Origin is the only extension
  • uBlock Origin with default lists/settings
  • using a new, unmodified browser profile
• I am running the latest version of uBlock Origin
• I checked the documentation to understand that the issue I report is not a normal behavior

Description

uBlock says it supports hosts files so I added https://raw.githubusercontent.com/notracking/hosts-blocklists/master/hostnames.txt. It seems to work fine except that the "::" at the beginning is interpreted as a filter and blocks some requests.

The other half of the notracking list is a Dnsmasq config file (https://github.com/notracking/hosts-blocklists/blob/master/domains.txt) with lines of the form address=/zzlayejqlzcg.com/:: and address=/zzzezeroe.fr/0.0.0.0; they seem to be parsed incorrectly as URL filters.

Unlike #576, notracking is a useful list not available in any formats uBlock supports. It contains many small lists not included elsewhere and the original sources are often in CSV or other strange formats.

A specific URL where the issue occurs

https://www.youtube.com/watch?v=spSxQjDguzM

Steps to Reproduce

1. Blocked URL requests happen in the middle of YouTube videos like the linked URL. The playback stops and the spinner appears. The logger shows URLs from googlevideo.com are being blocked because they contain ::.
2. URLs from the domain blocklist are not blocked

Expected behavior:

• :: is ignored like the 0.0.0.0 IP address.
• address= lines are parsed as hostname filters

Actual behavior:

• :: is interpreted as a generic filter rule.
• address lines are parsed as textual filters

Your environment

• uBlock Origin version: 1.24.2
• Browser Name and version: Firefox 71.0b12
• Operating System and version: Windows 10

[uBlock-user]

:: is not a hosts file format and shouldn't be used in a hosts file in the first place.

[uBlock-user]

notracking is a useful list

It's an overzealous list where the maintainer clearly doesn't care enough[1] to manually inspect the domains[2] before adding and collects them all via an automated script, not to mention he expects people to open an issue everytime his automated script blocks a valid domain without him ever inspecting the domain before adding.

[1] - notracking/hosts-blocklists#67
[2] - notracking/hosts-blocklists#100

Edit: adding what gorhill said in #576 --

It's making an issue of a non-issue, asking someone else to pointlessly invest efforts and time, and further suggesting to add complexity to the code base with no real benefit for end users given that all the lists given as examples are available in a format which can already be parsed by uBO.

Isn't :: IPv6 equivalent of 0.0.0.0? Or should it be ::/0/::/128 (default route / unspecified)?

Is it really useful in HOST files?

[gorhill]

uBO should discard :: from a hosts file, my understanding is that it's the equivalent of 0000:0000:0000:0000:0000:0000:0000:0000.

I will not support dnsmasq config file format, that is not a bug, that is a feature request which I declined in #576.

Dan Pollock’s hosts file contains this:

#<localhost>
127.0.0.1	localhost
127.0.0.1	localhost.localdomain
255.255.255.255	broadcasthost
::1		localhost
127.0.0.1	local
::1		ip6-localhost ip6-loopback
fe00::0		ip6-localnet
ff00::0		ip6-mcastprefix
ff02::1		ip6-allnodes
ff02::2		ip6-allrouters
ff02::3		ip6-allhosts
#fe80::1%lo0	localhost
#</localhost>

Skipped by reIsLocalhostRedirect?

[gorhill]

Skipped by reIsLocalhostRedirect?

Yes, https://regex101.com/r/Nh1V0R/1.