Invalid IP-assignment if assigned within pushed route

["Jonathan Petersson" <jpetersson garnser se>]

Hi all,

I've encountered something that seams like a bug.

The OpenVPN server I connect to assigns me a 10.100.40.X/24 IP. The
server is also pushing the range 10.100.0.0/16. As my client becomes
aware of it, it changes the assigned netmask resulting in 10.0.40.X/16
which causes various fun issues.

Please see the following log info:

Jan  8 22:59:39 jpetersson-desk1 nm-openvpn[14982]: TUN/TAP device tap0 opened
Jan  8 22:59:39 jpetersson-desk1 nm-openvpn[14982]: /sbin/ifconfig
tap0 10.100.40.5 netmask 255.255.255.0 mtu 1500 broadcast
10.100.40.255
Jan  8 22:59:39 jpetersson-desk1 vmnetBridge: RTM_NEWLINK: name:tap0
index:14 flags:0x00011043
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Joining mDNS
multicast group on interface tap0.IPv4 with address 10.100.40.5.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: New relevant
interface tap0.IPv4 for mDNS.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Registering new
address record for 10.100.40.5 on tap0.IPv4.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Withdrawing
address record for 10.100.40.5 on tap0.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Leaving mDNS
multicast group on interface tap0.IPv4 with address 10.100.40.5.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Interface
tap0.IPv4 no longer relevant for mDNS.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Joining mDNS
multicast group on interface tap0.IPv4 with address 10.100.40.5.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: New relevant
interface tap0.IPv4 for mDNS.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Registering new
address record for 10.100.40.5 on tap0.IPv4.
Jan  8 22:59:39 jpetersson-desk1 nm-openvpn[14982]:
/usr/lib/network-manager-openvpn/nm-openvpn-service-openvpn-helper
tap0 1500 1573 10.100.40.5 255.255.255.0 init
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  VPN
connection 'XXX--VPN-udp' (IP Config Get) reply received.
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  VPN Gateway:
123.123.123.123
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Internal
Gateway: 10.100.40.1
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Tunnel Device: tap0
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Internal IP4
Address: 10.100.40.5
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Internal IP4 Prefix: 16
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Internal IP4
Point-to-Point Address: 0.0.0.0
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Maximum
Segment Size (MSS): 0
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Static Route:
10.100.0.0/16   Next Hop: 10.100.0.0
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Internal IP4
DNS: 10.100.X.Y
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  DNS Domain: 'asd.asd'
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  Login Banner:
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>
-----------------------------------------
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>  (null)
Jan  8 22:59:39 jpetersson-desk1 NetworkManager: <info>
-----------------------------------------
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Withdrawing
address record for 10.100.40.5 on tap0.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Leaving mDNS
multicast group on interface tap0.IPv4 with address 10.100.40.5.
Jan  8 22:59:39 jpetersson-desk1 nm-openvpn[14982]: Initialization
Sequence Completed
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Interface
tap0.IPv4 no longer relevant for mDNS.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Joining mDNS
multicast group on interface tap0.IPv4 with address 10.100.40.5.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: New relevant
interface tap0.IPv4 for mDNS.
Jan  8 22:59:39 jpetersson-desk1 avahi-daemon[6615]: Registering new
address record for 10.100.40.5 on tap0.IPv4.
Jan  8 22:59:40 jpetersson-desk1 NetworkManager: <info>  (tap0):
writing resolv.conf to /sbin/resolvconf
Jan  8 22:59:40 jpetersson-desk1 NetworkManager: <info>  VPN
connection 'XXX--VPN-udp' (IP Config Get) complete.
Jan  8 22:59:40 jpetersson-desk1 NetworkManager: <info>  (eth0):
writing resolv.conf to /sbin/resolvconf
Jan  8 22:59:40 jpetersson-desk1 NetworkManager: <info>  Policy set
'Auto eth0' (eth0) as default for routing and DNS.
Jan  8 22:59:40 jpetersson-desk1 NetworkManager: <info>  VPN plugin
state changed: 4
Jan  8 22:59:40 jpetersson-desk1 nm-dispatcher.action: Script
'/etc/NetworkManager/dispatcher.d/01ifupdown' exited with error status
1.
Jan  8 22:59:41 jpetersson-desk1 avahi-daemon[6615]: Registering new
address record for fe80::f822:d7ff:febb:19b2 on tap0.*.
Jan  8 22:59:50 jpetersson-desk1 kernel: [ 7078.372254] tap0: no IPv6
routers present

/Jonathan