*##[src^="data:"] in My filters has no effect with easylist and/or fanboy-social

[emanruse]

Prerequisites

• This is NOT a YouTube, Facebook or Twitch report. These sites MUST be reported by clicking their respective links.
• I read and understand the policy about what is a valid filter issue.
• I verified that this issue is not a duplicate. (Search here to find out.)
• I did not remove any of the default filter lists, or I have verified that the issue was not caused by removing any of the default lists.
• I did not enable additional filter lists, or I have verified that the issue still occurs without enabling additional filter lists.
• I do not have custom filters/rules, or I have verified that the issue still occurs without custom filters/rules.
• I am not using uBlock Origin along with other content blockers.
• I have verified that the web browser's built-in blocker or DNS blocking (standalone or through a VPN) is not causing the issue.
• I have verified that other extensions are not causing the issue.
• If this is about a breakage or detection, I have verified that it is caused by uBlock Origin and isn't a site issue.
• I did not answer truthfully to ALL the above checkboxes.

URL(s) where the issue occurs.

https://github.com/404

Description

Disclaimer:

I am not 100% sure if this is correct to be reported as filter list issue or as an issue with uBO itself, in the sense that My Filters obviously has lower priority than external filter lists. So, for the sake of completeness, I will report it as both, because the documentation does not clarify which static filter has priority over another.

1. Use the following settings:

{
  "version": "1.56.0",
  "userSettings": {
    "firewallPaneMinimized": false,
    "importedLists": []
  },
  "selectedFilterLists": [
    "user-filters"
  ],
  "hiddenSettings": {},
  "whitelist": [
    "about-scheme",
    "moz-extension-scheme"
  ],
  "dynamicFilteringString": "* * * block\n* * inline-script block\n* * 1p-script block\n* * 3p-script block\n* * 3p-frame block\n* * image block\n* * 3p block\nbehind-the-scene * * block",
  "urlFilteringString": "",
  "hostnameSwitchesString": "no-popups: * true\nno-remote-fonts: * true\nno-large-media: * true\nno-csp-reports: * true\nno-scripting: * true",
  "userFilters": "*$stylesheet\n*$document,csp=style-src\n*##[src^=\"data:\"]\n"
}

2. Navigate to https://github.com/404

Expected: The *##[src^="data:"] in My Fiilters should hide the base64 images.

Actual: As expected.

3. Enable EasyList (easylist) or EasyList – Social Widgets (fanboy-social) filter lists. (or both)

4. Refresh the page (with disabled cache in web console).

Result: *##[src^="data:"] has no effect. base64 images are displayed.

Tested each and every other list (with all other lists disabled). Only the 2 lists mentioned above cause this effect.

Other extensions used

none

Screenshot(s)

I cannot enable JavaScript for privacy reasons. The STR is detailed and simple enough to reproduce and the result is consistent.

Configuration

Details

uBlock Origin: 1.56.0
Firefox: 115
filterset (summary):
 network: 47581
 cosmetic: 34229
 scriptlet: 0
 html: 0
listset (total-discarded, last-updated):
 removed:
  ublock-filters: null
  ublock-badware: null
  ublock-privacy: null
  ublock-unbreak: null
  ublock-quick-fixes: null
  easyprivacy: null
  urlhaus-1: null
  plowe-0: null
 default:
  user-filters: 3-0, never
  easylist: 81820-13, never
filterset (user): [array of 3 redacted]
trustedset:
 removed:
  chrome-extension-scheme
  chrome-scheme
  edge-scheme
  opera-scheme
  vivaldi-scheme
  wyciwyg-scheme
switchRuleset:
 added: [array of 4 redacted]
 removed:
  no-large-media: behind-the-scene false
hostRuleset:
 added: [array of 8 redacted]
 removed:
  behind-the-scene * * noop
  behind-the-scene * image noop
  behind-the-scene * 3p noop
  behind-the-scene * inline-script noop
  behind-the-scene * 1p-script noop
  behind-the-scene * 3p-script noop
  behind-the-scene * 3p-frame noop
userSettings: [none]
hiddenSettings: [none]
supportStats:
 allReadyAfter: 276 ms
 maxAssetCacheWait: 22 ms
 cacheBackend: browser.storage.local
popupPanel:
 blocked: 0
 no-large-media: true
 no-popups: true
 no-remote-fonts: true
 no-scripting: true

[gwarser]

Use specific filter (github.com##[src^="data:"]) or override the $ghide (*$ghide,important).

_{uBlockOrigin/uBlock-issues#3141}

[emanruse]

It does clarify, exception filters override normal filters : - https://help.adblockplus.org/hc/en-us/articles/360062733293-How-to-write-filters#allowlist - https://help.adblockplus.org/hc/en-us/articles/360062733293-How-to-write-filters#elemhide_exceptions

This only confirms that external filters can override user-set local ones, which makes the prioritization of "My filters" over external ones (the other issue) a valid one. The goal of *##[src^="data:"] is to block all base64 (on all sites). The github link was just an example to illustrate the issue. The suggested:

`github.com##[src^="data:"]` Or `com##[src^="data:"]` `@@||github.com^$generichide,badfilter`

are limited to a domain or TLD, i.e. the goal is still impossible.

or override the `$ghide` (`*$ghide,important`).

That works but wouldn't it have other (undesired) side effects? The point is: How does that resolve the actual issue of external filters overriding local ones?

- dynamic filtering gorhill/uBlock#2904 (comment)

Seems unrelated to in-document base64 data.

[emanruse]

What do you mean "to continue"? I am the author of both issues. Both were closed as "completed" without action whatsoever while the actual issue still remains. Quite confusing.

[emanruse]

*##[src^="data:"][src^="data:"]

Same result - the base64 images show up.

[krystian3w]

Instead wrote top 100 public suffixes or HTML filtering it is possible use untranslatable to a simple filter the injection of some CSS (yet/for now):

*##[src^="data:"]:style(display: none !important; width: unset)

(width: unset can by changed to anything like dummy: 1 to avoid simplification filter)

[Injection globally CSS is in use to disable advertising spectrum blocking detection, so blocking the use of this may unblock some spectrum blocking modals/alerts, if we consider it a bug that needs to be corrected in the next 10 years]

Or little slower :remove() (blinks at smartphone).

---

---

If placeholders with borders are not bad then also works:

*##[src^="data:"]:remove-attr(src)

(Also in legacy ra.js)

(https://github.com/uBlockOrigin/uAssets/assets/35370833/98c80a3e-a01e-4dda-afa3-91626f22594f)

[emanruse]

*##[src^="data:"]:style(display: none !important; width: unset)

Thanks. This works, even without "width: unset" (what's its purpose?)

[gwarser]

If I recall correctly, there was a code to treat :style(display: none !important;) as plain hiding filters (dropping the :style() altogether). Adding any other style will keep it as a styling filter. If it works without it, then maybe the purging code is in different code branch or it was changed.

[krystian3w]

Maybe this was limited to AG syntax only (used to disable see AG rules in CB for Android from Play Store, iPhones/iPads):

*#$#foo { display: none ! Important; }

But AdGuard no needs fallback with "aka All URL-s" e.g. legacy concept of his JS scripts rules (before accept new scriptlets system) still is injected on whole Internet.

[emanruse]

So is 'width: unset' necessary?

[krystian3w]

For now yes, check this on pressed Ctrl (or Command ⌘) + F5 to exclude load bugged cache.

[emanruse]

I have checked reloading with cache disabled. With or without 'width: unset' the result is the same but I accept your word that it is required (though I still don't understand why).

[krystian3w]

Mainly so that the filter compiler does not simplify this into a non-functioning title filter.

[emanruse]

OK. Thanks.

[gorhill]

there was a code to treat :style(display: none !important;) as plain hiding filters

This was probably before :style() filters could be injected declaratively.