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

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Message #26 received at 9196 <at> debbugs.gnu.org (full text, mbox):

From: Jan Djärv <jan.h.d <at> swipnet.se>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 9196 <at> debbugs.gnu.org
Subject: Re: bug#9196: integer and memory overflow issues (e.g., cut-and-paste
	crashes Emacs)
Date: Sun, 31 Jul 2011 10:57:20 +0200

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.

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