Re: Dumper problems and a possible solutions

[Rich Felker]

On Wed, Jun 25, 2014 at 04:06:33PM -0400, Stefan Monnier wrote:
> > Since emacs is processing lots of potentially untrusted data, PIE
> > hardening may be beneficial for hardening against vulnerabilities
> 
> IIUC what you mean by PIE, it requires a dumped Emacs where the position
> of the (pre-filled) heap can change at every invocation.  If so, that
> means relocation of all the pointers in the heap, at startup.

With the approach of dumping a C array containing references to
offsets within itself, this is completely transparent to the
application. The linker (ld) produces the right R_${ARCH}_RELATIVE
relocation records in the data segment and the dynamic linker applies
them at runtime.

> I had the impression you didn't want such relocation-at-startup (since
> you used it as an argument against XEmacs-style dumping into a separate
> heap file).

I didn't mean for that to be "an argument against XEmacs-style
dumping" since the XEmacs style is still much better than what GNU
emacs has now, simply an observation that it's not the ideal system.

Rich