Re: [PATCH 1/2] Avoid use after free

[NeilBrown <neilb@suse.de>]

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On Fri, 28 Oct 2011 21:50:50 +0200 Jes.Sorensen@redhat.com wrote:

> From: Jes Sorensen <Jes.Sorensen@redhat.com>
> 
> If picking just one spare disk from the container, jump out of the
> loop once freeing the list. Otherwise we end up accessing the list
> that we just freed.
> 
> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> ---
>  util.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/util.c b/util.c
> index 2cf617d..1bbd87f 100644
> --- a/util.c
> +++ b/util.c
> @@ -1766,6 +1766,7 @@ struct mdinfo *container_choose_spares(struct supertype *st,
>  			if (get_one) {
>  				sysfs_free(*dp);
>  				d->next = NULL;
> +				goto out;
>  			}
>  		} else {
>  			*dp = d->next;
> @@ -1773,5 +1774,6 @@ struct mdinfo *container_choose_spares(struct supertype *st,
>  			sysfs_free(d);
>  		}
>  	}
> +out:
>  	return disks;
>  }


Hi Jes,
  I dont' think patch is needed.
  The while loop that it jumps out of is
    while (*dp)

  at the place you put the goto,
     dp == &d->next
  As d->next was just set to NULL, *dp will be NULL, so the loop will
  exit with the need for a goto.

 I have applied the second patch - the GPT stack overflow one, thanks.

NeilBrown


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