I found this while debugging another thing locally on my desktop laptop. I was using docker, so that might have been a part of it as well. I don't have that dev environment intact anymore, so I can't go back and check to answer your questions, but I upgraded from 22.04 recently - so there might have been leftovers from the old install. Now when checking I have both reolvconf and systemd-resolved installed.
I have other working WG connections with DNS _not_ running Docker, so Docker might be a part of it as well. My proposed fix sorted the issue, but I'm sorry, I can't test anything else since I don't remember the exact system I had going. I now purged resolvconf anyway, so I hope that will sort any future issues. Thanks for your attention on this. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to resolvconf in Ubuntu. https://bugs.launchpad.net/bugs/2119260 Title: Bug: resolvconf_iface_prefix returns incorrect prefix for all interfaces Status in resolvconf package in Ubuntu: Invalid Status in wireguard package in Ubuntu: Fix Released Status in resolvconf source package in Noble: New Status in wireguard source package in Noble: Incomplete Status in resolvconf source package in Plucky: New Status in wireguard source package in Plucky: New Bug description: ### systemd version the issue has been seen with systemd 255 (255.4-1ubuntu8.10) ### Used distribution Ubuntu Desktop 24.03 ### Linux kernel version used 6.8.0-71-generic ### CPU architectures issue was seen on x86_64 ### Component resolvectl ### Expected behaviour you didn't see WG should work even with DNS set ### Unexpected behaviour you saw The `resolvconf_iface_prefix()` function in wg-quick returns the first matching pattern from `/etc/resolvconf/interface-order` without checking if the interface actually matches that pattern. ## Current broken code: ```bash resolvconf_iface_prefix() { [[ -f /etc/resolvconf/interface-order ]] || return 0 local iface while read -r iface; do [[ $iface =~ ^([A-Za-z0-9-]+)\*$ ]] || continue echo "${BASH_REMATCH[1]}." && return 0 done < /etc/resolvconf/interface-order } ```` ## Impact Returns "tun." for ALL interfaces when "tun*" is in interface-order Causes DNS setup to fail for WireGuard interfaces Affects any interface that doesn't match early patterns ### Steps to reproduce the problem 1. Run WG with DNS set ### Additional program output to the terminal or log subsystem illustrating the issue **Proposed fix** ```sh resolvconf_iface_prefix() { [[ -f /etc/resolvconf/interface-order ]] || return 0 local iface while read -r iface; do [[ $iface =~ ^#.*$ ]] && continue if [[ $iface =~ ^([A-Za-z0-9-]+)\*$ ]]; then local prefix="${BASH_REMATCH[1]}" if [[ $INTERFACE == ${prefix}* ]]; then echo "${prefix}." return 0 fi elif [[ $INTERFACE =~ $iface ]]; then echo "$iface/" return 0 fi done < /etc/resolvconf/interface-order } ``` Also added wg* to `/etc/resolvconf/interface-order` ``` # interface-order(5) lo.inet6 lo.inet lo.@(dnsmasq|pdnsd) lo.!(pdns|pdns-recursor) lo tun* tap* hso* vpn* em+([0-9])?(_+([0-9]))* p+([0-9])p+([0-9])?(_+([0-9]))* en+([bcosxpP])*([^.]).inet6 en+([bcosxpP])*([^.]).ip6.@(dhclient|dhcpcd|pump|udhcpc) en+([bcosxpP])*([^.]).inet en+([bcosxpP])*([^.]).@(dhclient|dhcpcd|pump|udhcpc) en+([bcosxpP])* @(br|eth)*([^.]).inet6 @(br|eth)*([^.]).ip6.@(dhclient|dhcpcd|pump|udhcpc) @(br|eth)*([^.]).inet @(br|eth)*([^.]).@(dhclient|dhcpcd|pump|udhcpc) @(br|eth)* wl+([bcosxpP])*([^.]).inet6 wl+([bcosxpP])*([^.]).ip6.@(dhclient|dhcpcd|pump|udhcpc) wl+([bcosxpP])*([^.]).inet wl+([bcosxpP])*([^.]).@(dhclient|dhcpcd|pump|udhcpc) wl+([bcosxpP])* @(ath|wifi|wlan)*([^.]).inet6 @(ath|wifi|wlan)*([^.]).ip6.@(dhclient|dhcpcd|pump|udhcpc) @(ath|wifi|wlan)*([^.]).inet @(ath|wifi|wlan)*([^.]).@(dhclient|dhcpcd|pump|udhcpc) @(ath|wifi|wlan)* ppp* wg* <---------------------- * ``` ProblemType: Bug DistroRelease: Ubuntu 24.04 Package: wireguard-tools 1.0.20210914-1ubuntu4 [modified: usr/bin/wg-quick] ProcVersionSignature: Ubuntu 6.8.0-71.71-generic 6.8.12 Uname: Linux 6.8.0-71-generic x86_64 NonfreeKernelModules: zfs ApportVersion: 2.28.1-0ubuntu3.8 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Fri Aug 1 00:48:34 2025 InstallationDate: Installed on 2022-05-05 (1183 days ago) InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419) SourcePackage: wireguard UpgradeStatus: Upgraded to noble on 2025-07-17 (14 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/resolvconf/+bug/2119260/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
