lkml.org 
[lkml]   [2010]   [Dec]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH] Ceph: Fix use-after-free bug in ceph_messenger_destroy()
From
On Sat, Dec 25, 2010 at 7:11 PM, Jesper Juhl <jj@chaosbits.net> wrote:
> Hi,
>
> In net/ceph/messenger.c::ceph_messenger_destroy() the pointer 'msgr' is
> freed by kfree() and subsequently used in a call to dout() - use after
> free bug.

As I sad before, %p reads only the address.

> Easily fixed by simply moving the kfree() call after the dout() call.
>
> Signed-off-by: Jesper Juhl <jj@chaosbits.net>
> ---
>  messenger.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
> index b6ff4a1..26514a7 100644
> --- a/net/ceph/messenger.c
> +++ b/net/ceph/messenger.c
> @@ -2131,8 +2131,8 @@ void ceph_messenger_destroy(struct ceph_messenger *msgr)
>        dout("destroy %p\n", msgr);
>        kunmap(msgr->zero_page);
>        __free_page(msgr->zero_page);
> -       kfree(msgr);
>        dout("destroyed messenger %p\n", msgr);
> +       kfree(msgr);
>  }
>  EXPORT_SYMBOL(ceph_messenger_destroy);
>
>
> --
> Jesper Juhl <jj@chaosbits.net>            http://www.chaosbits.net/
> Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
> Plain text mails only, please.
>
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>



--
Thanks,
//richard
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2010-12-25 22:17    [from the cache]
©2003-2011 Jasper Spaans