MozillaZine

FF68.0b2: Slowdown with standard Content Blocking enabled

Discussion about official Mozilla Firefox builds
dwkindig
 
Posts: 6
Joined: January 24th, 2017, 4:47 pm
Location: Oregon

Post Posted May 18th, 2019, 12:32 am

There's a website I visit which I whitelist in my uBlock Origin addon. It wouldn't be a big deal -- anything particularly egregious gets caught by Content Blocking -- BUT for the AddThis widget on these pages. Firefox correctly identifies the script "addthis_widget.js" as engaging in tracking and blocks it.

Image

And then the script tries again, about once every second-and-a-half, forever. And each time it does this, it makes the entirety of Firefox stutter, and pins the CPU usage of the main Firefox thread around 25-30%. I would think that Content Blocking would stop the script from running at the source, denying it from ever loading, but it looks like it's not identifying the source JS file itself (or the source domain) as a problem, but something the script is doing, and the script would just rather screw me over because AddThis is a catastrophe.

It's easy enough to just not whitelist the domain in uBO, but it's kind of annoying to then go through and selectively whitelist any features I'd otherwise be okay with. And (correct me if I'm wrong), uBO doesn't have a global blacklist that overrides the whitelist, so I can't say "always block *.addthis.com even if I say to run anything loaded on a specific website". I can achieve the same goal by blocking addthis.com in hosts or DNS, but it would be nice to have all of that managed in just one spot, either by having Firefox block it with the expected result of the script being stopped, or by learning how to setup uBO better or find a better alternative. Or to reach out to the website owners and say "Hey, you screwed up your AddThis integration".

Any thoughts? :-k

Brummelchen
 
Posts: 4601
Joined: March 19th, 2005, 10:51 am

Post Posted May 18th, 2019, 3:38 am

take your options on ublock to refine your page filter - then you will have luck with not needed (in any case) addthis crap. at least you are using b2 developer edition, so you are on business to deal with bugs, aint it?

dickvl

User avatar
 
Posts: 52840
Joined: July 18th, 2005, 3:25 am

Post Posted May 18th, 2019, 1:05 pm

It sounds that there is another script running that tries to (re)load this script and tries again after a timeout when this script isn't loaded.
You would have to block this script to prevent/block further attempts.

Can you possibly post a link to a publicly accessible and safe page ?

dwkindig
 
Posts: 6
Joined: January 24th, 2017, 4:47 pm
Location: Oregon

Post Posted May 18th, 2019, 8:28 pm

I didn't want to "name and shame" so to say, since they're a non-profit doing important work (and I don't even know if they are responsible for the site themselves, though even if they contract out I'm sure they'd like to know the issue exists so they can contact whoever their contractor is), but yeah, if you can identify what it would be, that would be a start for me to contact their local office. I can't see a control script that's trying to reload it, but I could easily be overlooking something.

The specific page(s) I've been using are for the Bike MS: Willamette Valley fundraiser (https://secure.nationalmssociety.org/si ... r_id=30230), but it appears to be affecting every page of theirs in the "secure" subdomain. Their pages at http://www.nationalmssociety.org don't have the same issue.

Brummelchen
 
Posts: 4601
Joined: March 19th, 2005, 10:51 am

Post Posted May 19th, 2019, 2:06 am

running b2 now with uBo and sharp filtering in firefox settings
BO doesn't have a global blacklist that overrides the whitelist, so I can't say "always block *.addthis.com even if I say to run anything loaded on a specific website". I can achieve the same goal by blocking addthis.com in hosts or DNS, but it would be nice to have all of that managed in just one spot, either by having Firefox block it with the expected result of the script being stopped,

ofc uBo can block regardless of this - use "my filters". the problem is that you cant turn uBo off for a page and turn "my filters" (cosmetic filters) on - thats not possible. what i can tell you that blocking addthis with a hosts file (i do) will result in a redirect (see uBo network logger --> "<<" is token for redirect right after blocking it). redirect is not common for this, its server controlled to have the rest proper running. happens also for other scripts, eg google-analytics.
don't have the same issue

possible because the script is not needed. it may have another target and it could be possible that not allowed.

not sure about your intention for addthis, either its blocked, there is nothing you can do because its e.g. "my" decision to block it. if it is not blocked, have luck. what i can tell you that your picture above means nothing else than "was blocked". i dont know why you watch the console while the network analysis is more important and the uBo network logger. and all of those only tell you why it was blocked on your system.

(anyhow it was NOT blocked here from firefox while uBo was off)

dwkindig
 
Posts: 6
Joined: January 24th, 2017, 4:47 pm
Location: Oregon

Post Posted May 19th, 2019, 1:07 pm

Brummelchen wrote:not sure about your intention for addthis


Ignore the fact that I want to block AddThis. I know there are ways I can block it with uBO or other means. The mere fact that the AddThis script is exhibiting this behavior -- where it tries to load itself every 1-1.5 seconds, which is causing Firefox to lag -- is all I'm here about. I don't need to know how to block it. What I am baffled by is that it's NOT being blocked correctly by Firefox's "Content Blocking" setting, as evidenced by the fact that the script keeps trying to reload itself (unlike with uBO, where blacklisting the AddThis domain correctly prevents the script from running at all, even to reload itself). That's why I'm here. "Content Blocking" in Firefox shouldn't be letting that happen, which means...:

  • Something is wrong with my setup (unlikely -- a completely fresh profile with no addons and the default "Content Blocking" setting has the same problem);
  • Something is wrong in Firefox (in which case I can submit a bug report);
  • AddThis has found a new way to circumvent privacy settings (in which case I can at least submit a report to see if the circumvention can be patched; AddThis are notorious for trying to find new ways of circumventing privacy settings); or
  • Something is wrong with the site itself (way more likely, and if I know what is wrong, I can go tell the good people running the site about it).

Brummelchen wrote:i dont know why you watch the console while the network analysis is more important


I don't know what I'd be looking for in network analysis. I only dabble. The symptoms all point to the AddThis script being the culprit, and causing Firefox to lag every time the AddThis script tries to establish a tracking cookie. In fact, it looks like it's trying to do this three times simultaneously, about every second:

Image

Brummelchen wrote:(anyhow it was NOT blocked here from firefox while uBo was off)


To be sure I'm clear on this: You went to the page at https://secure.nationalmssociety.org/si ... r_id=30230 with uBO turned off and with "Content Blocking" set to "Standard", and you did not observe the behavior where the AddThis script was trying to start itself every second or so? (I see where you said you use "sharp" filtering in Firefox settings; I'm going to assume that means "Content Blocking" was set to "Strict". It works as expected in "Strict" mode. It is not working as expected in "Standard" mode. If you did not use the "Standard" setting and still want to help, I'd ask you to again visit the site with "Content Blocking" set to "Standard", so you can see the problem in action.)

Soothsayer
 
Posts: 251
Joined: June 23rd, 2004, 8:24 am

Post Posted May 19th, 2019, 2:04 pm

You mention you have uBO off for this site, but do not mention how it is off - There are two ways to disable uBO for a site:

  • Add it to the whitelist (I suspect this is what you have done) - This will disable all uBO features for that site.
  • Use the uBO rules to allow everything and block specific items, if needed - This is a more flexible way to do it.

To try the second method, remove the site from the whitelist and create rules as follows:
Code: Select all
secure.nationalmssociety.org * * allow
secure.nationalmssociety.org addthis.com * block


The more specific block entry should take precedence over the generic allow entry.

You may need to play around with those rules a bit to get them working exactly as you want. There are instructions on the way to create them here:
https://github.com/gorhill/uBlock/wiki/ ... ule-syntax

dwkindig
 
Posts: 6
Joined: January 24th, 2017, 4:47 pm
Location: Oregon

Post Posted May 19th, 2019, 2:25 pm

Soothsayer wrote:To try the second method, remove the site from the whitelist and create rules as follows: [...]


Oh man, that is so obvious. Thanks for pointing that out, and linking to the relevant page of uBO's wiki (I admit I had trouble following along or knowing what to search for in it).

I am still curious why Firefox's "Content Blocking"'s default behavior only partially blocks the AddThis script in question, but you've saved me a ton of work getting around the problem.

Return to Firefox Builds


Who is online

Users browsing this forum: No registered users and 2 guests