** Patch added: "lp2111226_noble.debdiff" https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/2111226/+attachment/5879248/+files/lp2111226_noble.debdiff
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to openssh in Ubuntu. https://bugs.launchpad.net/bugs/2111226 Title: ssh@.service is still needed for hv_sock in Noble release Status in openssh package in Ubuntu: Fix Released Status in openssh source package in Jammy: Fix Released Status in openssh source package in Noble: In Progress Status in openssh source package in Oracular: Fix Released Status in openssh source package in Plucky: Fix Released Status in openssh source package in Questing: Fix Released Bug description: [Impact] On Ubuntu VMs running under Microsoft Hyper-V, users commonly rely on 'hv_sock' (Hyper-V socket) to enable seamless SSH access using the 'hvc.exe' tool on the Windows host. This works correctly on Ubuntu Jammy and earlier ( and Oracular and later with different mechanism ), but fails silently in Noble due to a missing 'ssh@.service' systemd unit. The failure is due to a combination of systemd and OpenSSH changes: * In older versions (e.g., Jammy with systemd 249), the 'ssh@.service' unit was relied upon for socket activation ('Accept=yes' mode) and the unit file exists. * With the Ubuntu Kinetic release, 'ssh@.service' was removed, and no template unit was shipped by default. * systemd introduced systemd-ssh-generator in version 256 checks sshd@.service unit and openssh provides sshd@.service unit. * Ubuntu Noble ships with systemd 255, which lacks this feature, resulting in the absence of sshd@.service. * Debian has restored a static 'sshd@.service' template in recent OpenSSH packaging. Noble’s OpenSSH package currently lacks it. As a result, the typical 'ssh.socket' activation workflow fails on Noble, breaking compatibility for 'hv_sock' SSH access. This issue affects all Ubuntu series between Kinetic and Noble (inclusive) where: * systemd < 256 is used (no dynamic generator) * 'ssh@.service' has been removed But I think Noble only needs SRU for now since the others are EOL. Basically user should setup ssh.socket correctly to use hv_sock(e.g changing Accept=no to Accept=yes) but creating whole service file (ssh@.service) might be different story since Jammy was working fine. [Test Case] 1. Launch a Noble VM on Hyper-V. 2. Ensure the 'hv_sock' kernel module is loaded: echo 'hv_sock' >> /etc/modules 3. Modify the socket unit for SSH to listen on vsock: # /lib/systemd/system/ssh.socket [Socket] ListenStream=vsock:22 Accept=yes 4. Reload and reconfigure systemd units: systemctl disable ssh.service systemctl daemon-reload systemctl stop ssh.service systemctl enable ssh.socket systemctl start ssh.socket 5. Attempt to connect from the Hyper-V host: hvc ssh user@ubuntu-vm Expected Result: Connection succeeds and SSH login is presented. Actual Result: The connection hangs. No systemd unit is spawned due to missing 'ssh@.service'. [Where problems could occur] Adding a static 'ssh@.service' template unit, as done in Debian(although it is sshd@.service), is unlikely to interfere with traditional SSH service setups (i.e., 'ssh.service'). The '@' template only activates in conjunction with 'Accept=yes' sockets and does not conflict with existing unit files. Also it was working in Jammy. [Other Info] * Debian commit restoring 'sshd@.service' https://salsa.debian.org/ssh-team/openssh/-/commit/eb25ab611967996a0d57b4ee565faa7de58b41f6 * systemd 256 adding 'systemd-ssh-generator' https://github.com/systemd/systemd/commit/0e3220684c6184a2f70396d991200ae207a25377 * OpenSSH in Ubuntu removed 'ssh@.service' in https://launchpadlibrarian.net/619116456/openssh_1%3A9.0p1-1_1%3A9.0p1-1ubuntu1.diff.gz during Kinetic development. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/2111226/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
