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

[Launchpad Bug Tracker]

*** This bug is a security vulnerability ***

You have been subscribed to a public security bug:

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.

** Affects: bash (Ubuntu)
     Importance: Undecided
         Status: New

** Affects: tcsh (Ubuntu)
     Importance: Undecided
         Status: New

-- 
subshell that instantly locks up bash, dash, ksh, tcsh, and zsh
https://bugs.launchpad.net/bugs/1213743
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