From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Daniel Borkmann , "David S. Miller" , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 56/80] net: cls_bpf: fix auto generation of per list handles Date: Thu, 19 Mar 2015 15:35:44 -0700 Message-Id: <1426804568-2907-57-git-send-email-kamal@canonical.com> In-Reply-To: <1426804568-2907-1-git-send-email-kamal@canonical.com> References: <1426804568-2907-1-git-send-email-kamal@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.13.11-ckt17 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann commit 3f2ab135946dcd4eb6af92a53d6d4bd35e7526ca upstream. 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 Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- 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 520b1a4..7181cf5 100644 --- a/net/sched/cls_bpf.c +++ b/net/sched/cls_bpf.c @@ -237,15 +237,21 @@ 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, -- 1.9.1