From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: Null pointer dereference in nf_nat_move_storage(), kernel 2.6.23.1 Date: Thu, 15 Nov 2007 15:55:09 -0800 (PST) Message-ID: <20071115.155509.107545186.davem@davemloft.net> References: <473B3874.2020104@redhat.com> <473B83DB.5040303@redhat.com> <20071115120658.GA17667@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: cebbert@redhat.com, netfilter-devel@vger.kernel.org, kaber@trash.net, netdev@vger.kernel.org To: johnpol@2ka.mipt.ru Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:43621 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1760059AbXKOXzK (ORCPT ); Thu, 15 Nov 2007 18:55:10 -0500 In-Reply-To: <20071115120658.GA17667@2ka.mipt.ru> Sender: netfilter-devel-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org From: Evgeniy Polyakov Date: Thu, 15 Nov 2007 15:06:59 +0300 > Please test attached patch. > > This routing is called each time hash should be replaced, nf_conn has > extension list which contains pointers to connection tracking users > (like nat, which is right now the only such user), so when replace takes > place it should copy own extensions. Loop above checks for own > extension, but tries to move higer-layer one, which can lead to above > oops. > > Not tested, derived from code observation only. > > Signed-off-by: Evgeniy Polyakov It looks extremely correct to me. Therefore I'm going to apply this and queue it up for -stable. Thanks Evgeniy, keep up the excellent work! Patrick, please let me know if you have any objections. > diff --git a/net/netfilter/nf_conntrack_extend.c b/net/netfilter/nf_conntrack_extend.c > index a1a65a1..cf6ba66 100644 > --- a/net/netfilter/nf_conntrack_extend.c > +++ b/net/netfilter/nf_conntrack_extend.c > @@ -109,7 +109,7 @@ void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) > rcu_read_lock(); > t = rcu_dereference(nf_ct_ext_types[i]); > if (t && t->move) > - t->move(ct, ct->ext + ct->ext->offset[id]); > + t->move(ct, ct->ext + ct->ext->offset[i]); > rcu_read_unlock(); > } > kfree(ct->ext); >