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Commit d883a036 authored by Denis V. Lunev's avatar Denis V. Lunev Committed by David S. Miller
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[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: default avatarDenis V. Lunev <den@openvz.org>
Signed-off-by: default avatarDavid 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);