debcrafters-packages team mailing list archive

[Seyeong Kim <2111226@xxxxxxxxxxxxxxxxxx>]

Verification for Plucky is also done. but I needed to disable
ssh.service(sshd-vsock.service, and random named service generated by
sshd generator) first.


PS C:\Users\one> hvc ssh ubuntu@plucky ( before upgrading, hang)
PS C:\Users\one> hvc ssh ubuntu@plucky ( after upgrading, ok, no question about key because it worked initially with sshd generator )
ubuntu@hyper-v/plucky's password:
Welcome to Ubuntu 25.04 (GNU/Linux 6.14.0-15-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/pro

 System information as of Mon Sep  1 07:10:08 AM UTC 2025

  System load:  0.18               Processes:             236
  Usage of /:   3.9% of 123.41GB   Users logged in:       0
  Memory usage: 62%                IPv4 address for eth0: 172.17.123.114
  Swap usage:   2%


134 updates can be applied immediately.
99 of these updates are standard security updates.
To see these additional updates run: apt list --upgradable


Last login: Mon Sep  1 06:52:44 2025 from UNKNOWN
ubuntu@plucky:~$ dpkg -l | grep openssh
ii  openssh-client                        1:9.9p1-3ubuntu3.2                         amd64        secure shell (SSH) client, for secure access to remote machines
ii  openssh-server                        1:9.9p1-3ubuntu3.2                         amd64        secure shell (SSH) server, for secure access from remote machines
ii  openssh-sftp-server                   1:9.9p1-3ubuntu3.2                         amd64        secure shell (SSH) sftp server module, for SFTP access from remote machines
ubuntu@plucky:~$


** Tags removed: verification-needed verification-needed-plucky
** Tags added: verification-done verification-done-plucky

-- 
You received this bug notification because you are a member of
Debcrafters packages, which is subscribed to openssh in Ubuntu.
https://bugs.launchpad.net/bugs/2111226

Title:
  sshd socket activation does not support AF_VSOCK

Status in openssh package in Ubuntu:
  Fix Released
Status in openssh source package in Jammy:
  Fix Released
Status in openssh source package in Noble:
  Fix Committed
Status in openssh source package in Oracular:
  Won't Fix
Status in openssh source package in Plucky:
  Fix Committed
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, but fails silently in Noble, because the logic in Ubuntu's systemd-socket-activation.patch silently rejects sockets that are not AF_INET or AF_INET6.

  Hence, when an AF_VSOCK socket is passed (which is supported by
  systemd socket's ListenStream=), the client connection silently hangs.

  [Test Case]

  The autopkgtests for openssh contain socket-activation tests to help
  avoid regressions in the existing logic. In addition to those tests,
  the below manual testing will be performed to verify the AF_VSOCK fix:

  Hyper-V:

  1. Launch a VM on Hyper-V, and ensure the hv_sock module is loaded:

  $ lsmod | grep hv_sock

  2. Adding the socket conf for SSH to listen on vsock:

  $ mkdir -p /etc/systemd/system/ssh.socket.d/
  $ cat > /etc/systemd/system/ssh.socket.d/vsock.conf << EOF
  [Socket]
  ListenStream=vsock::22
  EOF
  $ systemctl daemon-reload
  $ systemctl restart ssh.socket

  3. 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.

  Other methods:

  Alternatively, this can be verified using LXD VMs.

  $ lxc launch --vm ubuntu:$series test
  $ lxc shell test

  In the VM:

  $ mkdir -p /etc/systemd/system/ssh.socket.d/
  $ cat > /etc/systemd/system/ssh.socket.d/vsock.conf << EOF
  [Socket]
  ListenStream=vsock::22
  EOF
  $ systemctl daemon-reload
  $ systemctl restart ssh.socket

  Then, from the host:

  $ ssh -o StrictHostKeyChecking=no -o "ProxyCommand socat - VSOCK-
  CONNECT:$VSOCK_CID:22" ubuntu@localhost

  or, if new enough to have systemd-ssh-proxy

  $ ssh vsock/$VSOCK_CID

  [Where problems could occur]

  The effective goals of the patch are to (a) accept when AF_VSOCK
  sockets are passed by systemd, and (b) to close() (rather than
  silently ignore) unsupported socket types.

  There is additional logic to properly log about where the server is
  listening. This creates additional room for error.

  All of the changes are contained within the setup_systemd_socket()
  function. Therefore, problems would be seen when sshd is socket-
  activated, e.g. on the first connection attempt to a given server.

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