From: Florian Westphal <fw@xxxxxxxxx>
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 <houcheng@xxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
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 b1e3a05..8117fba 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);
--
1.7.10.4
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