bug#51105: 29.0.50; Buffer overflow bug in ns_compute_glyph_string_overhangs

[Alan Third]

On Sat, Oct 09, 2021 at 02:43:18PM +0300, Eli Zaretskii wrote:
> > From: Daniel Martín <mardani29@yahoo.es>
> > Cc: 51105@debbugs.gnu.org
> > Date: Sat, 09 Oct 2021 12:06:36 +0200
> > 
> > Now I think that the right thing to do may be to modify nsterm.m, switch
> > on the glyph type and, if the glyph type is COMPOSITE_GLYPH, call
> > composition_gstring_width to get the glyph metrics.  Function
> > composition_gstring_width uses the values from fields s->cmp_from and
> > s->cmp_to, and would avoid the buffer overflow:
> > 
> > (lldb) fr v s->cmp_from
> > (int) s->cmp_from = 6
> > (lldb) fr v s->cmp_to
> > (int) s->cmp_to = 7
> > 
> > WDYT? I can prepare a patch of this type if you agree.
> 
> SGTM, but I'd like to hear Alan's opinion as well, as I don't feel I
> know enough about the NS display backend.

I don't know much about this part of the code, but it sounds good to
me too.
-- 
Alan Third