race condition in if-up.d script

[LaMont Jones]

ifup -a with lots of new interfaces exposes a race condition in the init script:

lamont
-------
ssh start/running, process 9328
Set name-type for VLAN subsystem. Should be visible in /proc/net/vlan/config
cat: /var/run/sshd.pid: No such file or directory
ERROR: List of process IDs must follow -p.

[Clint Byrum (clint-fewbar)]

Ah, I think you meant if-up.d script not the "init" script.

Agreed, the l ast 3 lines are:

# We'd like to use 'reload' here, but it has some problems; see #502444.
stop ssh || true
start ssh || true

502444 is a debian bug # btw.

I think we need to serialize access to this section of the script with an flock o only one thing does this at a time.

[Launchpad Janitor (janitor)]

This bug was fixed in the package openssh - 1:7.9p1-1

---------------
openssh (1:7.9p1-1) unstable; urgency=medium

  * New upstream release (https://www.openssh.com/txt/release-7.9):
    - ssh(1), sshd(8): allow most port numbers to be specified using service
      names from getservbyname(3) (typically /etc/services; closes:
      #177406).
    - ssh(1): allow the IdentityAgent configuration directive to accept
      environment variable names. This supports the use of multiple agent
      sockets without needing to use fixed paths.
    - sshd(8): support signalling sessions via the SSH protocol. A limited
      subset of signals is supported and only for login or command sessions
      (i.e. not subsystems) that were not subject to a forced command via
      authorized_keys or sshd_config.
    - ssh(1): support "ssh -Q sig" to list supported signature options.
      Also "ssh -Q help" to show the full set of supported queries.
    - ssh(1), sshd(8): add a CASignatureAlgorithms option for the client and
      server configs to allow control over which signature formats are
      allowed for CAs to sign certificates. For example, this allows
      banning CAs that sign certificates using the RSA-SHA1 signature
      algorithm.
    - sshd(8), ssh-keygen(1): allow key revocation lists (KRLs) to revoke
      keys specified by SHA256 hash.
    - ssh-keygen(1): allow creation of key revocation lists directly from
      base64-encoded SHA256 fingerprints. This supports revoking keys using
      only the information contained in sshd(8) authentication log messages.
    - ssh(1), ssh-keygen(1): avoid spurious "invalid format" errors when
      attempting to load PEM private keys while using an incorrect
      passphrase.
    - sshd(8): when a channel closed message is received from a client,
      close the stderr file descriptor at the same time stdout is closed.
      This avoids stuck processes if they were waiting for stderr to close
      and were insensitive to stdin/out closing (closes: #844494).
    - ssh(1): allow ForwardX11Timeout=0 to disable the untrusted X11
      forwarding timeout and support X11 forwarding indefinitely.
      Previously the behaviour of ForwardX11Timeout=0 was undefined.
    - sshd(8): when compiled with GSSAPI support, cache supported method
      OIDs regardless of whether GSSAPI authentication is enabled in the
      main section of sshd_config. This avoids sandbox violations if GSSAPI
      authentication was later enabled in a Match block.
    - sshd(8): do not fail closed when configured with a text key revocation
      list that contains a too-short key.
    - ssh(1): treat connections with ProxyJump specified the same as ones
      with a ProxyCommand set with regards to hostname canonicalisation
      (i.e. don't try to canonicalise the hostname unless
      CanonicalizeHostname is set to 'always').
    - ssh(1): fix regression in OpenSSH 7.8 that could prevent public-key
      authentication using certificates hosted in a ssh-agent(1) or against
      sshd(8) from OpenSSH <7.8 (LP: #1790963).
    - All: support building against the openssl-1.1 API (releases 1.1.0g and
      later). The openssl-1.0 AP...