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af-packet: fix - avoid reading stale data

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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: Chetan Loke <loke.chetan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Chetan Loke 2011-07-14 08:36:33 -07:00 committed by David S. Miller
parent 6a7ebdf2fd
commit cc9f01b246
1 changed files with 2 additions and 1 deletions
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3
net/packet/af_packet.c
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@ -1129,7 +1129,6 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
else else
sll->sll_ifindex = dev->ifindex; sll->sll_ifindex = dev->ifindex;
__packet_set_status(po, h.raw, status);
smp_mb(); smp_mb();
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1 #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); end = (u8 *)PAGE_ALIGN((unsigned long)h.raw + macoff + snaplen);
for (start = h.raw; start < end; start += PAGE_SIZE) for (start = h.raw; start < end; start += PAGE_SIZE)
flush_dcache_page(pgv_to_page(start)); flush_dcache_page(pgv_to_page(start));
smp_wmb();
} }
#endif #endif
__packet_set_status(po, h.raw, status);
sk->sk_data_ready(sk, 0); sk->sk_data_ready(sk, 0);