Fw: [Bug 202287] New: netfilter/iptales prevents Tor Browser from closing cleanly

Fw: [Bug 202287] New: netfilter/iptales prevents Tor Browser from closing cleanly

[Stephen Hemminger]

Begin forwarded message:

Date: Tue, 15 Jan 2019 16:18:13 +0000
From: bugzilla-daemon@bugzilla.kernel.org
To: stephen@networkplumber.org
Subject: [Bug 202287] New: netfilter/iptales prevents Tor Browser from closing cleanly


https://bugzilla.kernel.org/show_bug.cgi?id=202287

            Bug ID: 202287
           Summary: netfilter/iptales prevents Tor Browser from closing
                    cleanly
           Product: Networking
           Version: 2.5
    Kernel Version: 4.20
          Hardware: Intel
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: IPV4
          Assignee: stephen@networkplumber.org
          Reporter: jb.1234abcd@gmail.com
        Regression: No

Created attachment 280501
  --> https://bugzilla.kernel.org/attachment.cgi?id=280501&action=edit  
Tpr Browser and kernels run log

Since kernel 4.20 there is a problem with Tor Browser (TB) on close.
The last good kernel was 4.19.12 .

Tested:
kernel 4.20.1 and 4.19.12 .
Tor Browser 8.0.4 (prod version).

Tor Browser (TB) and kernel run logs (as attached):
tor-netfilter-4.20.1-and-4.19.12.txt

kernel 4.20.1
Results:
There is a problem with TB on close:
- TB process left behind
- INVALID messages (ACK FIN and ACK PSH FIN) cought in OUTPUT chain of
iptables,
  on lo interface, and logged to system log/journal.
  -A OUTPUT -m conntrack --ctstate INVALID -j loginv

kernel 4.19.12
Results:
There is no problem with TB, i.e. clean close.

There is an old reference to this problem
https://www.linode.com/community/questions/2495/iptables-drop-ackfin-as-invalid

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Re: Fw: [Bug 202287] New: netfilter/iptales prevents Tor Browser from closing cleanly

[Florian Westphal]

Stephen Hemminger <stephen@networkplumber.org> wrote:
> Date: Tue, 15 Jan 2019 16:18:13 +0000
> From: bugzilla-daemon@bugzilla.kernel.org
> To: stephen@networkplumber.org
> Subject: [Bug 202287] New: netfilter/iptales prevents Tor Browser from closing cleanly
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=202287
> Created attachment 280501
>   --> https://bugzilla.kernel.org/attachment.cgi?id=280501&action=edit  
> Tpr Browser and kernels run log
> 
> Since kernel 4.20 there is a problem with Tor Browser (TB) on close.
> The last good kernel was 4.19.12 .
> - INVALID messages (ACK FIN and ACK PSH FIN) cought in OUTPUT chain of
> iptables,
>   on lo interface, and logged to system log/journal.
>   -A OUTPUT -m conntrack --ctstate INVALID -j loginv

Can't reproduce this so far:

:INPUT ACCEPT [225785:239821136]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [189532:100424913]
[0:0] -A INPUT -i lo -m conntrack --ctstate INVALID
[0:0] -A OUTPUT -o lo -m conntrack --ctstate INVALID

this is with a different setup, do not know what TB might be doing
differently.

Can you do
modprobe nf_log_ipv4
sysctl 'net.netfilter.nf_log.2=nf_log_ipv4'
sysctl 'net.netfilter.nf_conntrack_log_invalid=6'

and see what that might turn up for those 'invalid' packets?
(should appear in dmesg/system log/journal).