Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='x86_64'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='x86_64-redhat-linux-gnu'
-DCONF_VENDOR='redhat' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL
-DHAVE_CONFIG_H -I. -I. -I./include -I./lib -D_GNU_SOURCE -DRECYCLES_PIDS
-DDEFAULT_PATH_VALUE='/usr/local/bin:/usr/bin' -O2 -g -pipe -Wall
-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
-fexceptions -fstack-protector-strong -grecord-gcc-switches
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
-fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection
-Wno-parentheses -Wno-format-security
uname output: Linux vineyard.localdomain 4.20.14-200.fc29.x86_64 #1 SMP Tue Mar
5 19:55:32 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Machine Type: x86_64-redhat-linux-gnu
Bash Version: 4.4
Patch Level: 23
Release Status: release
Description:
Under the circumstances described below, the following command crashes Bash:
echo '' > >(echo)
Replacing '' with "", ' ', or " " has the same effect.
Replacing >(echo) with >( echo ) has the same effect (spaces added).
Please see the old bug titled "Fatal bug with redirection". It gives the
following command:
{ echo a >&3 ; } 3> >( echo b )
That command has the same effect, however, like the one I give first, it
only crashes Bash
*once* per login, a property not mentioned in the old bug's mailing thread.
Below, I give further details on how the bug is associated with log-ins.
Repeat-By:
#################################################
# #
# Heads-up: this is an intermittent bug. #
# The below recipe is as close to a guarantee #
# of recreation as I can get you. #
# #
#################################################
* Restart computer
* Log in to *one* tty only. I have not determined whether a second tty
login alters the behavior of this bug.
* Open a Bash prompt. I am using KDE, so my terminal emulator is Konsole.
* Do the command given in the title.
* In my case, this results in Konsole giving me an error:
Warning: Program '/bin/bash' crashed.
* Now, open another tab in your terminal emulator or open a new window of
it and do the command again.
No error this time. (Usually.)
* Log out of your GUI and log back in. Repeat. You'll see that again, you
get the error once per log-in.
-- Part 2 --
* Log out of GUI and log back in.
* Open terminal emulator. Log in to a shell within a shell with either
just "su" or "su [non-root user]"
* Enter the command. It crashes with:
Broken pipe
and kicks you back to the parent shell.
* Repeat the "shell within a shell" thing and, again, enter the command.
It does not break this time. Exit inner shell.
* Enter the command in the outer shell. Again, it does *not* crash
(usually).
-- Part 3 --
* Log out of your GUI.
* Does logging-out take longer than normal? Does it get really stuck and
force you to open another tty to restart your machine?
I have witnessed both. I have also witnessed it having little to no
effect on how long it takes to log out.
Additional Notes:
* One time I did Part 2 with just "su" and the outer shell still crashed. At
this moment, I consider the incident a fluke.
Again, understand that this bug is intermittent.
