[Bug 1213743] Re: subshell that instantly locks up bash, dash, ksh, tcsh, and zsh

[Axel Beckert]

*** This bug is a duplicate of bug 1206370 ***
    https://bugs.launchpad.net/bugs/1206370

** Changed in: zsh (Ubuntu)
       Status: New => Invalid

** This bug has been marked a duplicate of bug 1206370
   subshell that instantly locks up bash, dash, ksh, tcsh, and zsh

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https://bugs.launchpad.net/bugs/1213743

Title:
  subshell that instantly locks up bash, dash, ksh, tcsh, and zsh

Status in “bash” package in Ubuntu:
  New
Status in “dash” package in Ubuntu:
  New
Status in “ksh” package in Ubuntu:
  New
Status in “tcsh” package in Ubuntu:
  New
Status in “zsh” package in Ubuntu:
  Invalid

Bug description:
  Type this at a shell prompt in gnome-terminal:

  $ (yes&)
  y
  y
  y
  y
  y
  y
  ...

  Denial of service. Shell becomes totally unresponsive. Subshell
  command is uninterruptible.

  An old one that affects bash, dash, ksh, tcsh, and zsh shells at least
  in all versions in Ubuntu and further back in Ubuntu pre-history too.

  Please note the issue is not related to
  https://wiki.ubuntu.com/SecurityTeam/Policies#Unlimited_Local_Resource_Utilization

   $ (yes &)
  is not a fork bomb or any other kind of resource overutilization. There is only one subshell and only one subprocess being executed in it.

  The issue is with buggy signal handling.

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