Re: Seg fault on "echo ~nosuchuser"

[Keith Thompson]

On Fri, May 29, 2020 at 11:40 AM Chet Ramey <chet.ramey@case.edu> wrote:
>
> On 5/28/20 6:12 PM, Keith Thompson wrote:
> > Configuration Information [Automatically generated, do not change]:
> > Machine: x86_64
> > OS: linux-gnu
> > Compiler: gcc
> > Compilation CFLAGS: -g -Wno-parentheses -Wno-format-security
> > uname output: Linux bomb20 5.4.0-31-generic #35-Ubuntu SMP Thu May 7
> > 20:20:34 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
> > Machine Type: x86_64-pc-linux-gnu
> >
> > Bash Version: 5.0
> > Patch Level: 16
> > Release Status: release
> >
> > Description:
> > bash crashes with a segmentation fault on the command:
> >     echo ~nosuchuser
> > (This assumes there is no user named "nosuchuser".  If there
> > is, pick a different name).
> >
> > It's likely this isn't a bug in bash itself, but I haven't
> > been able to figure out what's going on.
> >
> > I see this problem on copies of bash 5.0.16 and 5.0.17 built from
> > sourced on Ubuntu 20.04 LTS.  It does *not* occur with the /bin/bash
> >     GNU bash, version 5.0.16(1)-release (x86_64-pc-linux-gnu)
> > provided by the distribution.  I haven't verified how far
> > back this goes.
>
> Can you try this with the current devel branch head from savannah? I
> have a suspicion about what's going on.
>
> http://git.savannah.gnu.org/cgit/bash.git/snapshot/bash-devel.tar.gz

This did not reproduce the bug.

$ ./bash --version
GNU bash, version 5.1.0(1)-alpha (x86_64-pc-linux-gnu)
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
$ ./bash -c 'echo ~nosuchuser'
~nosuchuser
$