Subject: ax.25 on kernels above 4.1

From: Brian <[email-masked]>
Date: Sat, 25 Apr 2020 11:52:18 -0400

Package: linux-image
Version: all above 4.1

There's a critical bug in the ax.25 module that popped up beginning with
kernel version 4.2 where if a user connected to a site using NetRom, the
underlaying ax.25 virtual circuit fails to close thus leaving a zombie
socket open and available for possible attack. This has been a known
issue on the URONode email list for quite some time, and I'm the
developer of the uronode package in your repositories.  

A fix was supplied by Marius YO2LOJ on the list:

---
Let me explain the patch so maybe you can do it yourself, since the
code 
will probably not work on a 5.x kernel...

The target function is ax25_disconnect(ax25_cb *ax25, int reason).

The function is in the file ax25_subr.c in the 4.9 version.

the last part is an:

if (ax25->sk != NULL) {

(...the ax25 socket is closed here...)

}

This if catches only full ax25 connections, not the ones associated with 
netrom connections.

So for netrom connections, we also need a socket deletion, so add to 
this if the following else:

else {

ax25_destroy_socket(ax25);

}

Maybe this helps get you going...

Marius, YO2LOJ
---

A weblink to his mail:
https://n1uro.ampr.org/cgi-bin/mailman/private/uronode/2019-September/001284.html
however it's only available to subscribers.

-- 
If Confucius were alive today:
"A computing device left in the OFF power state never crashes" 
-----
73 de Brian N1URO
IPv6 Certified
SMTP: n1uro-at-n1uro.ampr.org

---

From: Mark Hindley <[email-masked]>
Date: Sat, 25 Apr 2020 18:01:37 +0100

Control: tags -1 debian

> Version: all above 4.1

Brian,

Thanks for this. However the linux kernel packages are not forked in Devuan and
we use the Debian packages directly.

You would be better reporting this to bugs.debian.org.

Thanks

Mark