bugLibreJS - Bugs: bug #50551, installation in Firefox 54.0a2...


bug #50551: installation in Firefox 54.0a2 (2017-03-15) results in ALL sites returning compressed responses being blocked

Submitted by:  None
Submitted on:  Wed 15 Mar 2017 12:10:55 PM UTC  
Votes:  200  
Category:  None Severity:  4 - Important
Item Group:  None Status:  Wont Fix
Privacy:  Public Assigned to:  zach wick <zwick>
Open/Closed:  Open

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Fri 23 Feb 2018 04:07:54 AM UTC, comment #3:

libreJS v7 is now considered to be the current stable release and is a nearly total re-write; so this issue very likely refers to only to the previous version that was obsoleted my mozilla - all further development will be on libreJS v7 so this issue is marked as "wont-fix" for now (previously "Confirmed") unless it can be show to pertain also to libreJS v7

as this behavior was seen using libreJS v6, could someone try libreJS v7 on a firefox derivative >= v57 to see if the same issue still exists?

bill-auger <bill_auger>
Project Member
Sat 15 Apr 2017 08:52:54 AM UTC, comment #2:

Same behaviour on Firefox 52.0.2 on Arch GNU/Linux

Mike <mikee3000>
Sun 26 Mar 2017 02:36:05 PM UTC, comment #1:

Anecdotally, I've seen this behavior on my work machine (a macOS machine).

zach wick <zwick>
Project AdministratorIn charge of this item.
Wed 15 Mar 2017 12:10:55 PM UTC, original submission:

Today I decided to give LibreJS a try, installing it in
my Firefox 54.0a2 (Developer Edition, Aurora Channel)
x86_64 Linux browser .

After installation, ALL sites, including
are blocked - attempts to make any request from them
result in the error:
'Content Encoding Error:
The page you are trying to view cannot be shown because
it uses an invalid or unsupported form of compression.

Please contact the web site owners to inform them of this

Here are the request header and responses from LibreJS site:
Request URL: http://savannah.gnu.org/projects/librejs/
Request method: GET
Remote address: http://savannah.gnu.org/projects/librejs/
Status code: 200
Version: HTTP/2.0
Host: savannah.gnu.org
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:54.0) Gecko/20100101 Firefox/54.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip
Connection: keep-alive
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0, no-cache
Pragma: no-cache

Note the status code is 200 (OK) . Something in LibreJS is
rejecting the response because it is compressed , as it does
for http://www.google.com:

Request URL: https://www.google.ie/?gws_rd=cr,ssl&ei=oSfJWMD5NuaBgAa_nLeYCw

Actually, I requested 'https://www.google.com', but am
redirected to the above URL. A tool to disable this redirection
would be more valuable to have than a working LibreJS !

Request method: GET
Remote address:
Status code: 200
Version: HTTP/2.0

Response headers (311 B)
Date: "Wed, 15 Mar 2017 11:39:30 GMT"
Expires: "-1"
Cache-Control "private, max-age=0"
Content-Type: "text/html; charset=UTF-8"
Server: "gws"
x-xss-protection:"1; mode=block"
x-frame-options: "SAMEORIGIN"
Alt-Svc: "quic=\":443\"; ma=2592000; v=\"36,35,34\""
X-Firefox-Spdy: "h2"
Request headers (903 B)
Host: "www.google.ie"
User-Agent: "Mozilla/5.0 (X11; Linux x86_6… Gecko/20100101 Firefox/54.0"
Accept: "text/html,application/xhtml+x…lication/xml;q=0.9,*/*;q=0.8"
Accept-Language: "en-GB,en;q=0.5"
Accept-Encoding: "gzip, deflate, br"
Cookie: "NID=99=X5qE1d1COaUAMzbSTmWPNK…-KRjBbmwqB; OGPC=5061821-25:"
Connection: "keep-alive"
Upgrade-Insecure-Requests: "1"
Cache-Control: "max-age=0"

In both cases, the 'Content Encoding Error' occurs, even though
the negotiated content encoding is 'gzip' . Is 'gzip' now
'an invalid or unsupported form of compression' ?

Why is LibreJS concerning itself at all with the Content Encoding - I thought its only job was to detect non-free / obfuscated JavaScript ?

It must be something to do with LibreJS, since simply disabling
the add-on fixes the problem & allows me to browse the web again.

I would like a tool like LibreJS to detect & complain about
proprietary & obfuscated JavaScript, which IMHO are destroying the usability of the web .

Better luck with future versions!

Thanks & Regards,



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Carbon-Copy List
  • -email is unavailable- added by bill_auger (Posted a comment)
  • -email is unavailable- added by usename135 (Voted in favor of this item)
  • -email is unavailable- added by barslmn (Voted in favor of this item)
  • -email is unavailable- added by mikee3000 (Posted a comment)
  • -email is unavailable- added by zwick (Posted a comment)
  • -email is unavailable- added by jvd (Reporter of this bug (sorry, didn't mean to file anonymously).)

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    Follow 7 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2018-02-23 bill_auger StatusConfirmed => Wont Fix
    2017-07-28 usename135 Carbon-Copy- => Added usename135
    2017-06-21 barslmn Carbon-Copy- => Added barslmn
    2017-03-26 zwick Severity3 - Normal => 4 - Important
        StatusNone => Confirmed
        Assigned toNone => zwick
    2017-03-15 jvd Carbon-Copy- => Added reporter

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