Commit 4eb2e134 authored Aug 13, 2020 by Sabrina Dubroca Committed by Steffen Klassert Aug 17, 2020

espintcp: restore IP CB before handing the packet to xfrm



Xiumei reported a bug with espintcp over IPv6 in transport mode,
because xfrm6_transport_finish expects to find IP6CB data (struct
inet6_skb_cb). Currently, espintcp zeroes the CB, but the relevant
part is actually preserved by previous layers (first set up by tcp,
then strparser only zeroes a small part of tcp_skb_tb), so we can just
relocate it to the start of skb->cb.

Fixes: e27cca96 ("xfrm: add espintcp (RFC 8229)")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

parent 61ee4137

net/xfrm/espintcp.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -29,8 +29,12 @@ static void handle_nonesp(struct espintcp_ctx ctx, struct sk_buff skb,

		static void handle_esp(struct sk_buff skb, struct sock sk)
		{
		struct tcp_skb_cb tcp_cb = (struct tcp_skb_cb )skb->cb;

		skb_reset_transport_header(skb);
		memset(skb->cb, 0, sizeof(skb->cb));

		/* restore IP CB, we need at least IP6CB->nhoff */
		memmove(skb->cb, &tcp_cb->header, sizeof(tcp_cb->header));

		rcu_read_lock();
		skb->dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif);

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