From cc9f01b246ca8e4fa245991840b8076394f86707 Mon Sep 17 00:00:00 2001 From: Chetan Loke 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 Signed-off-by: David S. Miller --- 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 d2294ad..c698cec 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); -- 2.7.4