netfilter/iptables and network interface names

[Thomas Woerner <twoerner@redhat.com>]

Hello,

I just fell over network interface definitions in kernel and 
netfilter/iptables.

Interfaces names in the kernel have few limits: Only spaces and slashes 
are not allowed, but everything else, even Ctrl characters are.

In iptables, there are other limits: Colon, exclamation mark and 
asterisk are not allowed. The plus is treated special for matching. But 
what will be matched if the interface starts with or contains a plus?

iptables allows to use interfaces containing spaces and slashes. 
iptables-save is not escaping interface names. The interface "+" will be 
treated as no interface limit at all and will be dropped, therefore all 
interfaces match.

I think there should be some discussion about interface names and limits 
in kernel and netfilter/iptables.

What do you think?

Thanks in advance,
Thomas Woerner