1611472 - 72.0+ not handling 403 response from proxy properly (only https)

Status: VERIFIED FIXED

(Core :: Networking, defect, P1)

Description

[ericj]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:72.0) Gecko/20100101 Firefox/72.0

Steps to reproduce:

In both 72.0.1 and 72.0.2, (72.0 works properly though), going through a proxy (squid in my case), visit a page the proxy does not allow you to, and it will give a 403 response.

Tested on a fresh profile in safe mode. Occurs in both Linux (openSUSE 15.1 x86_64) and Windows.

Actual results:

When the proxy responds with 403 on an http page, it shows the custom squid 403 error document.

But on an https page, Firefox did not display anything in the browser. Developer Tools Network tab shows the 403 response, but the contents of the page is empty (if you already had another page up prior, it leaves the contents of the old page up and changes the URL back to the old page (almost looks like a redirect back to the old page)).

Problem started with 72.0.1 (also occurs in 72.0.2), but is not a problem in 72.0.

Expected results:

http would give the custom squid 403 error document; and https should state connection is refused.

Comment 1

[Augusto Pace]

Hi,

I was able to reproduce this issue on Windows 10 with Firefox version Nightly 74.0a1 (2020-01-28) (64-bit) - Beta 73.0b10 (64-bit) - Release 72.0.2 (64-bit). Marking those flags as affected.

This seems to be an issue with squid proxy. I've tried with Charles Proxy and it does work correctly. I'm setting component to Core - Networking and changing status to New for someone to take a look at this.

Comment 2

[Valentin Gosu [:valentin] (he/him)]

(In reply to Augusto Pace from comment #1)

This seems to be an issue with squid proxy. I've tried with Charles Proxy and it does work correctly. I'm setting component to Core - Networking and changing status to New for someone to take a look at this.

Sounds like squid proxy is doing something differently, triggering this bug.
Honza, can you take a look?

Comment 3

[Honza Bambas (:mayhemer)]

Just to make sure I understand the problem: having a proxy (http or https aka http/2?) and connecting an https site, that is blacklisted by the proxy, you expect a proper Firefox connection error page to show on the screen?

I'm a bit puzzled by the assertion that this used to work in 72 and got broken in 72.0.1+. 72.0.1 has only a single patch in the JS engine that is unrelated to displaying error pages. Because the only bug coming to my mind that could clearly break it is bug 1579049, which was fixed on 72. Adding Kershaw to be aware.

ericj, can you please double check that this is really getting broken between the first major and the first dot-release of 72? (same major version). Thanks.

Comment 4

[ericj]

Apologies - I just re-tested in 72.0 and it is indeed broken. I have also just tested 71.0 and it is NOT broken in 71.0.

Comment 5

[Honza Bambas (:mayhemer)]

Thanks! Looks like we are missing an error page assignment for the error code bound to 403.

Comment 6

[ericj]

Fixed title to reflect 72.0+

Comment 7

[Honza Bambas (:mayhemer)]

In docshell we need to add the error to show the error page for proxyConnectFailure

Kershaw, can you add it?

Comment 8

[Kershaw Chang [:kershaw]]

Attachment: Bug 1611472 - Add missing error codes

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0c65b9c71a77
Add missing error codes r=mayhemer

Comment 10

[Daniel Varga [:dvarga]]

https://hg.mozilla.org/mozilla-central/rev/0c65b9c71a77

Comment 11

[Anca Soncutean, Desktop QA]

I've reproduced this issue using squid proxy with Fx 74.0a1 (2020-01-24) on Windows 10.
The issue is verified fixed with Fx 74.0b7 and Fx 75.0a1 (2020-02-24) on Windows 10 and Ubuntu 18.04.