From 9dfa1dfe4d5e5e66a991321ab08afe69759d797a Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 23 Oct 2014 10:36:06 +0200 Subject: [PATCH 1/1] netfilter: nf_log: account for size of NLMSG_DONE attribute We currently neither account for the nlattr size, nor do we consider the size of the trailing NLMSG_DONE when allocating nlmsg skb. This can result in nflog to stop working, as __nfulnl_send() re-tries sending forever if it failed to append NLMSG_DONE (which will never work if buffer is not large enough). Reported-by: Houcheng Lin Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_log.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c index b1e3a0579416..8117fba8e661 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -649,7 +649,8 @@ nfulnl_log_packet(struct net *net, + nla_total_size(sizeof(u_int32_t)) /* gid */ + nla_total_size(plen) /* prefix */ + nla_total_size(sizeof(struct nfulnl_msg_packet_hw)) - + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp)); + + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp)) + + nla_total_size(sizeof(struct nfgenmsg)); /* NLMSG_DONE */ if (in && skb_mac_header_was_set(skb)) { size += nla_total_size(skb->dev->hard_header_len) @@ -692,8 +693,7 @@ nfulnl_log_packet(struct net *net, goto unlock_and_release; } - if (inst->skb && - size > skb_tailroom(inst->skb) - sizeof(struct nfgenmsg)) { + if (inst->skb && size > skb_tailroom(inst->skb)) { /* either the queue len is too high or we don't have * enough room in the skb left. flush to userspace. */ __nfulnl_flush(inst); -- 2.20.1