From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: [PATCH 3/3] netfilter: nf_log: release skbuff on nlmsg put failure Date: Thu, 23 Oct 2014 10:36:08 +0200 Message-ID: <1414053368-29037-4-git-send-email-fw@strlen.de> References: <1414053368-29037-1-git-send-email-fw@strlen.de> Cc: Houcheng Lin , Florian Westphal To: netfilter-devel@vger.kernel.org Return-path: Received: from Chamillionaire.breakpoint.cc ([80.244.247.6]:49323 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753097AbaJWIgT (ORCPT ); Thu, 23 Oct 2014 04:36:19 -0400 In-Reply-To: <1414053368-29037-1-git-send-email-fw@strlen.de> Sender: netfilter-devel-owner@vger.kernel.org List-ID: From: Houcheng Lin The kernel should reserve enough room in the skb so that the DONE message can always be appended. However, in case of e.g. new attribute erronously not being size-accounted for, __nfulnl_send() will still try to put next nlmsg into this full skbuf, causing the skb to be stuck forever and blocking delivery of further messages. Fix issue by releasing skb immediately after nlmsg_put error and WARN() so we can track down the cause of such size mismatch. [ fw@strlen.de: add tailroom/len info to WARN ] Signed-off-by: Houcheng Lin Signed-off-by: Florian Westphal --- net/netfilter/nfnetlink_log.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c index 2d02eac3..5f1be5b 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -346,26 +346,25 @@ nfulnl_alloc_skb(struct net *net, u32 peer_portid, unsigned int inst_size, return skb; } -static int +static void __nfulnl_send(struct nfulnl_instance *inst) { - int status = -1; - if (inst->qlen > 1) { struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0, NLMSG_DONE, sizeof(struct nfgenmsg), 0); - if (!nlh) + if (WARN_ONCE(!nlh, "bad nlskb size: %u, tailroom %d\n", + inst->skb->len, skb_tailroom(inst->skb))) { + kfree_skb(inst->skb); goto out; + } } - status = nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid, - MSG_DONTWAIT); - + nfnetlink_unicast(inst->skb, inst->net, inst->peer_portid, + MSG_DONTWAIT); +out: inst->qlen = 0; inst->skb = NULL; -out: - return status; } static void -- 2.0.4