From b51d3fa364885a2c1e1668f88776c67c95291820 Mon Sep 17 00:00:00 2001 From: Houcheng Lin Date: Thu, 23 Oct 2014 10:36:08 +0200 Subject: [PATCH] netfilter: nf_log: release skbuff on nlmsg put failure 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 Signed-off-by: Pablo Neira Ayuso --- 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 2d02eac35415..5f1be5ba3559 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 -- 2.20.1