bug#9196: integer and memory overflow issues (e.g., cut-and-paste crashes Emacs)

[Jan Djärv]

Paul Eggert skrev 2011-07-30 21:16:
> I take your point that the checks add clutter, so I'll
> revise the patch to address that problem, by adding a
> couple of memory allocators that do the proper overflow
> checking internally, so that callers don't need to
> test for integer overflow.
>
> This will take a bit of time to prepare and test, so
> please bear with me, but to give you a feel here's a draft
> of the revised patch to xgselect.c.  This simplifies
> xgselect.c compared to what's in the trunk now.

That is a good approach, very nice.

> --- src/xgselect.c      2011-07-01 09:18:46 +0000
> +++ src/xgselect.c      2011-07-30 18:19:51 +0000
> @@ -54,10 +54,8 @@
>     do {
>       if (n_gfds>  gfds_size)
>         {
> -        while (n_gfds>  gfds_size)
> -          gfds_size *= 2;
>           xfree (gfds);
> -        gfds = xmalloc (sizeof (*gfds) * gfds_size);
> +        gfds = xpmalloc (&gfds_size, n_gfds - gfds_size, INT_MAX, sizeof 
> *gfds);
>         }
>
>       n_gfds = g_main_context_query (context,

        Jan D.