From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: [PATCH net 2/2] net: cls_bpf: fix auto generation of per list handles Date: Thu, 22 Jan 2015 10:41:02 +0100 Message-ID: <1421919662-21066-3-git-send-email-dborkman@redhat.com> References: <1421919662-21066-1-git-send-email-dborkman@redhat.com> Cc: jiri@resnulli.us, netdev@vger.kernel.org To: davem@davemloft.net Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35589 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751533AbbAVJlL (ORCPT ); Thu, 22 Jan 2015 04:41:11 -0500 In-Reply-To: <1421919662-21066-1-git-send-email-dborkman@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: When creating a bpf classifier in tc with priority collisions and invoking automatic unique handle assignment, cls_bpf_grab_new_handle() will return a wrong handle id which in fact is non-unique. Usually altering of specific filters is being addressed over major id, but in case of collisions we result in a filter chain, where handle ids address individual cls_bpf_progs inside the classifier. Issue is, in cls_bpf_grab_new_handle() we probe for head->hgen handle in cls_bpf_get() and in case we found a free handle, we're supposed to use exactly head->hgen. In case of insufficient numbers of handles, we bail out later as handle id 0 is not allowed. Fixes: 7d1d65cb84e1 ("net: sched: cls_bpf: add BPF-based classifier") Signed-off-by: Daniel Borkmann Acked-by: Jiri Pirko --- net/sched/cls_bpf.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c index 49e5fa8..f59adf8 100644 --- a/net/sched/cls_bpf.c +++ b/net/sched/cls_bpf.c @@ -220,15 +220,21 @@ static u32 cls_bpf_grab_new_handle(struct tcf_proto *tp, struct cls_bpf_head *head) { unsigned int i = 0x80000000; + u32 handle; do { if (++head->hgen == 0x7FFFFFFF) head->hgen = 1; } while (--i > 0 && cls_bpf_get(tp, head->hgen)); - if (i == 0) + + if (unlikely(i == 0)) { pr_err("Insufficient number of handles\n"); + handle = 0; + } else { + handle = head->hgen; + } - return i; + return handle; } static int cls_bpf_change(struct net *net, struct sk_buff *in_skb, -- 1.7.11.7