[Bug 1814905] Re: dash exits when receiving wall message

[Launchpad Bug Tracker]

[Expired for dash (Ubuntu) because there has been no activity for 60
days.]

** Changed in: dash (Ubuntu)
       Status: Incomplete => Expired

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https://bugs.launchpad.net/bugs/1814905

Title:
  dash exits when receiving wall message

Status in dash package in Ubuntu:
  Expired

Bug description:
  When using "/bin/sh" (dash) as a shell for ssh, or just starting
  /bin/sh in a terminal, when the shell receives a wall message (from
  another user or root), it just quits.

  How to reproduce:
  - start a terminal (xterm, gnome-terminal, etc), usually starts with bash
  - from bash run 'sh' command to open a dash shell
  - start another terminal, and run: echo "foo" | wall
  - the broadcast message appears on both terminals
  - in the first terminal you are thrown back to bash, because dash exits

  I've tried this on Ubuntu 14.04, 16.04, 18.04 (64bits) latest updates
  and it's happening on all of them. I've also tried with latest dash
  from git, compiled on Ubuntu 16.04, same problem, that's why I don't
  think it's dash's problem.

  Also tried on CentOS 7, there is no problem there.

  The problem appears this morning (6 February) after updating to latest
  version of 16.04, 18.04. I also have a box with 16.04 but not the
  latest updates, and on that box the problem does not happen.

  If one uses dash as a login shell, and enters on a remote box with SSH
  for example, the connection can be terminated by another user simply
  wall'ing a broadcast message (or a system daemon like NUT). This could
  be taken as a potential security issue.

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