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Commit cc9f01b2 authored by Chetan Loke's avatar Chetan Loke Committed by David S. Miller
Browse files

af-packet: fix - avoid reading stale data 



Currently we flush tp_status and then flush the remainder of the header+payload.
tp_status should be flushed in the end to avoid stale data being read by user-space.

Incorrectly re-ordered barriers in v1.

Signed-off-by: default avatarChetan Loke <loke.chetan@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6a7ebdf2

net/packet/af_packet.c

+2 −1
Original line number Diff line number Diff line
@@ -1129,7 +1129,6 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, 
	else

		sll->sll_ifindex = dev->ifindex;



	__packet_set_status(po, h.raw, status);

	smp_mb();

#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1

	{
@@ -1138,8 +1137,10 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, 
		end = (u8 *)PAGE_ALIGN((unsigned long)h.raw + macoff + snaplen);

		for (start = h.raw; start < end; start += PAGE_SIZE)

			flush_dcache_page(pgv_to_page(start));

		smp_wmb();

	}

#endif

	__packet_set_status(po, h.raw, status);



	sk->sk_data_ready(sk, 0);