Re: bash -n: stack overflow in extract_delimited_string()

[Jakub Wilk]

* Chet Ramey <chet.ramey@case.edu>, 2020-08-03, 09:15:
> On 8/3/20 5:30 AM, Jakub Wilk wrote:
>
> > Bash Version: 5.0
> > Patch Level: 18
> > Release Status: release
> >
> > bash crashes with stack overflow when checking syntax of this crafted script:
> >
> >   $ ulimit -s
> >   8192
> >
> >   $ printf 'x[$(($(fi)))`\n%050000d\n][`]\n' | tr 0 '(' | bash -n
> >   bash: command substitution: line 4: syntax error near unexpected token `fi'
> >   bash: command substitution: line 4: `fi)))`'
> >   Segmentation fault
>
> I can't reproduce this with bash-5.1-alpha.

Oh right, looks like this was fixed in the 20191108 snapshot, probably 
by this change:

parse.y
        - xparse_dolparen: if the command substitution is incomplete or doesn't
          end in `)', print an error message instead of allowing EOS to
          terminate the comsub. From a bug report from
          Oguz <oguzismailuysal@gmail.com>

--
Jakub Wilk