One Crash per Log-in Caused by: echo '' > >(echo)

[jake]

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.