[NETFILTER]: nfnetlink_log: fix sending of multipart messages
The following patch fixes the handling of netlink packets containing
multiple messages.
As exposed during netfilter workshop, nfnetlink_log was overwritten the
message type of the last message (setting it to MSG_DONE) in a multipart
packet. The consequence was libnfnetlink to ignore the last message in the
packet.
The following patch adds a supplementary message (with type MSG_DONE) af
the end of the netlink skb.
Signed-off-by: Eric Leblond <eric@inl.fr>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index e185a5b..2351533 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -58,7 +58,6 @@
unsigned int qlen; /* number of nlmsgs in skb */
struct sk_buff *skb; /* pre-allocatd skb */
- struct nlmsghdr *lastnlh; /* netlink header of last msg in skb */
struct timer_list timer;
int peer_pid; /* PID of the peer process */
@@ -345,10 +344,12 @@
static int
__nfulnl_send(struct nfulnl_instance *inst)
{
- int status;
+ int status = -1;
if (inst->qlen > 1)
- inst->lastnlh->nlmsg_type = NLMSG_DONE;
+ NLMSG_PUT(inst->skb, 0, 0,
+ NLMSG_DONE,
+ sizeof(struct nfgenmsg));
status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
if (status < 0) {
@@ -358,8 +359,8 @@
inst->qlen = 0;
inst->skb = NULL;
- inst->lastnlh = NULL;
+nlmsg_failure:
return status;
}
@@ -538,7 +539,6 @@
}
nlh->nlmsg_len = inst->skb->tail - old_tail;
- inst->lastnlh = nlh;
return 0;
nlmsg_failure:
@@ -644,7 +644,8 @@
}
if (inst->qlen >= qthreshold ||
- (inst->skb && size > skb_tailroom(inst->skb))) {
+ (inst->skb && size >
+ skb_tailroom(inst->skb) - sizeof(struct nfgenmsg))) {
/* either the queue len is too high or we don't have
* enough room in the skb left. flush to userspace. */
UDEBUG("flushing old skb\n");