[Bug 1767283] Re: nc doesn't support "-s IP" option

[ Christian Ehrhardt ]

Thanks Stefan, updating the tags per former comment.

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

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https://bugs.launchpad.net/bugs/1767283

Title:
  nc doesn't support "-s IP" option

Status in netcat-openbsd package in Ubuntu:
  Fix Released
Status in netcat-openbsd source package in Bionic:
  Fix Committed
Status in netcat-openbsd package in Debian:
  Fix Released

Bug description:
  [Impact]

   * This worked in former relases, so from a LTS->LTS upgraders POV it is 
     an upgrade regression
   * The impact is that local source (-s) can no more be used as before
   * The fix is backporting the fix that we made in Debian (but without all 
     the noise of the arg parsing rewrite for SRU simplicity)

  [Test Case]

   * Run with local source port, like your local SSH for example:
       $ netcat -s 127.0.0.1 127.0.0.1 22 < /dev/null

  [Regression Potential]

   * the Minimized change (compared to the big change that versions going 
     forward got) should be safe as it just allows a case that was formerly 
     forbidden in arg-parsing. Never the less there could be a regression if 
     one of those combinations causes an issue when ran where it formerly 
     just was denied on arg parse. Think a script that since Bionic fails 
     (due to this bug) but once enabled will "work" and DUE TO THAT might 
     then trigger actions that are an issue.
     Never the less, since currently in Bionic this just fails, I'd assume 
     the this is a rather theoretical risk - and being a regression to 
     former releases we should fix it to make LTS->LTS upgraders suffer 
     less.

  [Other Info]
   
   * n/a


  Hey,

  netcat shows a usage error if i try to use the "-s" option:

  Example in Bionic:

  $ netcat -s 127.0.0.1 127.0.0.1 22 < /dev/null
  usage: nc [-46CDdFhklNnrStUuvZz] [-I length] [-i interval] [-M ttl]
     [-m minttl] [-O length] [-P proxy_username] [-p source_port]
     [-q seconds] [-s source] [-T keyword] [-V rtable] [-W recvlimit] [-w timeout]
     [-X proxy_protocol] [-x proxy_address[:port]] 	  [destination] [port]

  Example in Xenial:

  netcat -s 127.0.0.1 127.0.0.1 22 < /dev/null
  SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.4

  Manpage shows that the option is still availible and should work. Both
  systems use openbsd netcat.

  $ type netcat
  netcat is hashed (/bin/netcat)
  $ ls -lah /bin/netcat
  lrwxrwxrwx 1 root root 24 Apr 25 21:56 /bin/netcat -> /etc/alternatives/netcat
  $ ls -lah /etc/alternatives/netcat
  lrwxrwxrwx 1 root root 15 Apr 25 21:56 /etc/alternatives/netcat -> /bin/nc.openbsd

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: netcat-openbsd 1.187-1
  ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
  Uname: Linux 4.15.0-20-generic x86_64
  ApportVersion: 2.20.9-0ubuntu7
  Architecture: amd64
  Date: Fri Apr 27 13:41:20 2018
  Dependencies:
   gcc-8-base 8-20180414-1ubuntu2
   libbsd0 0.8.7-1
   libc6 2.27-3ubuntu1
   libgcc1 1:8-20180414-1ubuntu2
  ProcEnviron:
   TERM=xterm
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: netcat-openbsd
  UpgradeStatus: No upgrade log present (probably fresh install)

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