bug#63063: CVE-2021-36699 report

[Eli Zaretskii <eliz@gnu.org>]

> From: Po Lu <luangruo@yahoo.com>
> Cc: fuomag9 <fuo@fuo.fi>,  63063@debbugs.gnu.org
> Date: Tue, 25 Apr 2023 15:24:31 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Please tell more about the buffer overflow: where does it happen in
> > the Emacs sources, which buffer overflows, and why.  I cannot find
> > these details in your report.
> 
> It happens because the dump file is deliberately edited to be invalid.

I didn't ask about the root cause, I asked about the details of the
problem: where it happens in our sources, and what exactly happens.

> It is not a dump file that Emacs will generate under any circumstance,
> and as such it's not a bug; by the same means, a pointer to an invalid
> Lisp object could be created, causing a similar crash.  Emacs is not
> expected to operate from a corrupt dump file any more than it is
> expected to operate from a corrupt executable.

Noted.  But please let me make up my own mind about this issue, once I
understand the details.  OK?