Commit d883a036 authored Dec 21, 2007 by Denis V. Lunev Committed by David S. Miller Dec 21, 2007

[IPV4]: OOPS with NETLINK_FIB_LOOKUP netlink socket



[ Regression added by changeset:
	cd40b7d3
	[NET]: make netlink user -> kernel interface synchronious
  -DaveM ]

nl_fib_input re-reuses incoming skb to send the reply. This means that this
packet will be freed twice, namely in:
- netlink_unicast_kernel
- on receive path
Use clone to send as a cure, the caller is responsible for kfree_skb on error.

Thanks to Alexey Dobryan, who originally found the problem.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1ac70e7a

net/ipv4/fib_frontend.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -804,10 +804,13 @@ static void nl_fib_input(struct sk_buff *skb)

		nlh = nlmsg_hdr(skb);
		if (skb->len < NLMSG_SPACE(0) \|\| skb->len < nlh->nlmsg_len \|\|
		nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn))) {
		kfree_skb(skb);
		nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn)))
		return;
		}

		skb = skb_clone(skb, GFP_KERNEL);
		if (skb == NULL)
		return;
		nlh = nlmsg_hdr(skb);

		frn = (struct fib_result_nl *) NLMSG_DATA(nlh);
		tb = fib_get_table(frn->tb_id_in);

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