From cc9f01b246ca8e4fa245991840b8076394f86707 Mon Sep 17 00:00:00 2001
From: Chetan Loke <loke.chetan@gmail.com>
Date: Thu, 14 Jul 2011 08:36:33 -0700
Subject: [PATCH] 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: Chetan Loke <loke.chetan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/packet/af_packet.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index d2294ad1a895..c698cec0a445 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -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);
--
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