1363342 - Firefox over proxychains bypasses proxy and reaches the internet directly

Status: RESOLVED INCOMPLETE

(Core :: Networking, defect)

Description

[Rubén Martín [:Nukeador] ❌ [away till Aug 31st]]

Hi,

I've been using Nightly together with proxychains to tunnel the browser connection through a local proxy for a long time now.

Just recently nightly updates have broken this and Firefox access the internet directly even when it's run from proxychains.

Proxychains config is:

socks4  127.0.0.1 9050

Nightly is run by:

proxychains /opt/nightly/firefox

Every other app keeps working as expected and directing traffic through the proxy, but not Nightly any more.

Are there any recent changes that could have influenced in this behaviour? I've tested with clean profiles getting the same problem.

Thanks!

Comment 1

[Honza Bambas (:mayhemer)]

Gary, is it something you could take a look at?

Comment 2

[Daniel Stenberg [:bagder]]

What platform are you seeing this problem on with Nightly? proxychains is simply a SOCKS4 proxy to Firefox, right?

Do you happen know when this problem started for you? Narrowing down the window will help finding the culprit faster...

Comment 3

[Gary Chen [:xeonchen]]

[1] explains the way how proxychains works, and it probably doesn't work for e10s environment.
Would you first try to disable e10s (uncheck "enable multi-process" in preference) and see if it works?

If the root cause it not because Firefox doesn't honor the system/browser proxy setting, I'll consider to mark this bug as invalid. A workaround for you is you may choose to use SOCKS4 proxy in the preferences panel and explicitly set to 127.0.0.1:9050. 

[1] https://github.com/rofl0r/proxychains-ng

Comment 4

[Gary Chen [:xeonchen]]

Cervantes, do you know any possibility that we're doing something to prevent Firefox being hooked?

Comment 5

[Cervantes Yu [:cyu] [:cervantes]]

I am not sure, but preventing LD_PRELOAD hooks doesn't sound likely. I suggest checking this under gdb to find out whether the proxychains-ng functions are taking effect in the parent process.

Comment 6

[Gary Chen [:xeonchen]]

I cannot reproduce this bug on Nightly 2017-06-05 64-bit Linux, proxychains 3.1

proxychains.conf:
socks4  127.0.0.1 9050 # Tor

connect to https://check.torproject.org/ and it shows I'm configured to use Tor.

Rubén, can you still reproduce this bug?

Comment 7

[Rubén Martín [:Nukeador] ❌ [away till Aug 31st]]

You are right, latest nightly is working correctly and connections are traveling through the proxy.

Comment 8

[Rubén Martín [:Nukeador] ❌ [away till Aug 31st]]

Apparently the issue is back since yesterday's build.

Comment 9

[Gary Chen [:xeonchen]]

I still cannot reproduce this
Rubén, is this reproducible in another clean platform?

Comment 10

[Gary Chen [:xeonchen]]

No sufficient information to handle this bug, I'm going to close this until we have more info.