[Bug 1838038] Re: [snap] Snapped apps do not work with .local mdns/avahi name resolution
Just repeating what I said on the forum, I believe this could be implemented through updates to the base snaps with no changes to snapd or any application snaps. The mdns4_minimal NSS plugin is an 18K binary (which compresses to about 6KB) that delegates its lookups to avahi-daemon using a single purpose lookups-only unix socket protocol (i.e. no D-Bus access). The AppArmor policy fragment grants access to this socket, so any snap plugging "network" already has permission to communicate. If the plugin cannot connect to Avahi, it should error out very quickly. Updating the base snaps to include the NSS plugin and reference it in their nsswitch.conf file would likely be all that is needed. It should work equally well for applications on classic distros and those on Ubuntu Core with the avahi snap installed. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1838038 Title: [snap] Snapped apps do not work with .local mdns/avahi name resolution To manage notifications about this bug go to: https://bugs.launchpad.net/snap-core18/+bug/1838038/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1838038] Re: [snap] Snapped apps do not work with .local mdns/avahi name resolution
Applied a Snap-side workaround to my Snaps which implements the fix presented in the snapcraft.io thread mentioned in my previous post: CUPS Snap: https://github.com/OpenPrinting/cups-snap/commit/f241f3f02 PostScript Printer Application: https://github.com/OpenPrinting/ps-printer-app/commit/1f6ca389 Note that doing this on any Snap which needs it in the future is awkward, so we really need to fix core18 and core20. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1838038 Title: [snap] Snapped apps do not work with .local mdns/avahi name resolution To manage notifications about this bug go to: https://bugs.launchpad.net/snap-core18/+bug/1838038/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1838038] Re: [snap] Snapped apps do not work with .local mdns/avahi name resolution
Adding snap-core18 and snap-core20 tasks as it is a problem of core18 and core20 missing support for looking up host names via mDNS/DNS-SD. The problem occurs also in other Snaps not only in the Chromium Browser Snap. Therefore the fix for this bug is essentially important and urgently needed. Note that installing nscd is only a workaround, which can cause security problems (aacording to Jamie Strandboge) when seeding it and also it would only help Ubuntu users. Especially also the CUPS Snap (https://github.com/OpenPrinting/cups- snap) and Printer Application Snaps (the way to snap printer and scanner drivers, required for the CUPS Snap, currently, we have the PostScript Printer Application, https://github.com/OpenPrinting/ps-printer-app) are affected as they internally use mDNS .local addresses to access network devices. As we want to switch over printing in Ubuntu to the CUPS Snap and also want to give manufacturers a way to publish distribution- independent snapped printer/scanner drivers this problem needs to get urgently fixed. A suggested fix can be found in this thread: https://forum.snapcraft.io/t/no-mdns-support-in-snaps-should-core-have-a -modified-nsswitch-conf/ The /etc/nsswitch.conf file needs a simple change, replacing the line hosts: files dns by hosts: files mdns4_minimal [NOTFOUND=return] dns and the libnss-mdns package (provides libnss_mdns*.so*) needs to get installed into the coreXX images. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1838038 Title: [snap] Snapped apps do not work with .local mdns/avahi name resolution To manage notifications about this bug go to: https://bugs.launchpad.net/snap-core18/+bug/1838038/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1838038] Re: [snap] Snapped apps do not work with .local mdns/avahi name resolution
** Also affects: snap-core20 Importance: Undecided Status: New ** Also affects: snap-core18 Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1838038 Title: [snap] Snapped apps do not work with .local mdns/avahi name resolution To manage notifications about this bug go to: https://bugs.launchpad.net/snap-core18/+bug/1838038/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1838038] Re: [snap] Snapped apps do not work with .local mdns/avahi name resolution
Now with nscd running and snapd restarted I have also cloded and re- opened the Chromium browser and I can access my printer's web interface now. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1838038 Title: [snap] Snapped apps do not work with .local mdns/avahi name resolution To manage notifications about this bug go to: https://bugs.launchpad.net/snapd/+bug/1838038/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1838038] Re: [snap] Snapped apps do not work with .local mdns/avahi name resolution
I have to install nscd on the host machine and then restart snapd and my snap: sudo systemctl restart snapd sudo snap restart printing-stack-snap and after that cups-browsed succeeds to resolve .local host names. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1838038 Title: [snap] Snapped apps do not work with .local mdns/avahi name resolution To manage notifications about this bug go to: https://bugs.launchpad.net/snapd/+bug/1838038/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
