[pve-devel] [PATCH ifupdown2 1/1] fix #5197: do not run scripts ending with .dpkg-{old, new, tmp, dist}

[Friedrich Weber]

On 27/06/2024 17:01, Stefan Hanreich wrote:
> This can lead to issue when upgrading from ifupdown to ifupdown2. The
> particular issue this fixes occurs in the following scenario:
> 
> * Suppose there is a legacy Debian host with ifupdown and ifenslave
>   installed that has a bond configured in /etc/network/interfaces.
> * ifenslave installs a script /etc/network/if-pre-up.d/ifenslave.
> * Now, an upgrade creates a second script
>   /etc/network/if-pre-up.d/ifenslave.dpkg-new. As ifupdown executes
>   network scripts via run-parts which ignores scripts with . in their
>   name, ifenslave.dpkg-new has no effect.
> * If the host switches over to ifupdown2 by installing it (removing
>   ifupdown, keeping ifenslave) and reboots, the network will not come
>   up:
>   /etc/network/if-pre-up.d/ifenslave still exists, but is ignored
>   by ifupdown2's bond addon [1]
>   /etc/network/if-pre-up.d/ifenslave.dpkg-new is executed by ifupdown2
>   because it executes all scripts in /etc/network/if-pre-up.d, even if
>   their name contains a dot
> 
> This leads to ifreload failing on upgrades, which in turn causes
> issues with the networking of upgraded hosts.

Thanks for tackling this! Consider this

Tested-by: Friedrich Weber <f.weber at proxmox.com>

I tested the following:

- Set up a PVE8 VM with an active-backup bond, from /etc/network/interfaces:

> auto bond0
> iface bond0 inet manual
> 	bond-slaves ens18 ens19
> 	bond-miimon 100
> 	bond-mode active-backup
> 
> auto vmbr0
> iface vmbr0 inet static
> 	address 10.1.1.122/16
> 	gateway 10.1.1.1
> 	bridge-ports bond0
> 	bridge-stp off
> 	bridge-fd 0

- Install ifupdown and ifenslave
- Manually create a .dpkg-new:

>  cp /etc/network/if-pre-up.d/ifenslave /etc/network/if-pre-up.d/ifenslave.dpkg-new

- Reboot -- network comes up fine.
- Install latest packaged ifupdown2:

> apt install ifupdown2=3.2.0-1+pmx8

- Network is already lost during install
- Reboot -- network does not come up, bond0 and vmbr0 report NO-CARRIER
- Install ifupdown2 with this patch applied
- Reboot -- network comes up fine
- Running `execsnoop -l network & sleep 3; ifreload -a` confirms
ifenslave.dpkg-new is never executed (ifenslave is never executed by
ifupdown2, see the pull request linked by Stefan)