[092/118] netfilter: don't reset nf_trace in nf_reset()

Ben Hutchings
2013-05-10T14:20:48Z

From: Patrick McHardy <kaber@trash.net>

[ Upstream commit 124dff01afbdbff251f0385beca84ba1b9adda68 ]

Commit 130549fe ("netfilter: reset nf_trace in nf_reset") added code
to reset nf_trace in nf_reset(). This is wrong and unnecessary.

nf_reset() is used in the following cases:

- when passing packets up the the socket layer, at which point we want to
release all netfilter references that might keep modules pinned while
the packet is queued. nf_trace doesn't matter anymore at this point.

- when encapsulating or decapsulating IPsec packets. We want to continue
tracing these packets after IPsec processing.

- when passing packets through virtual network devices. Only devices on
that encapsulate in IPv4/v6 matter since otherwise nf_trace is not
used anymore. Its not entirely clear whether those packets should
be traced after that, however we've always done that.

- when passing packets through virtual network devices that make the
packet cross network namespace boundaries. This is the only cases
where we clearly want to reset nf_trace and is also what the
original patch intended to fix.

Add a new function nf_reset_trace() and use it in dev_forward_skb() to
fix this properly.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
include/linux/skbuff.h | 7 +++++++
net/core/dev.c | 1 +
2 files changed, 8 insertions(+)

--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2367,6 +2367,13 @@ static inline void nf_reset(struct sk_bu
#endif
}

+static inline void nf_reset_trace(struct sk_buff *skb)
+{
+#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
+ skb->nf_trace = 0;
+#endif
+}
+
/* Note: This doesn't put any conntrack and bridge info in dst. */
static inline void __nf_copy(struct sk_buff *dst, const struct sk_buff *src)
{
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1619,6 +1619,7 @@ int dev_forward_skb(struct net_device *d
skb->mark = 0;
secpath_reset(skb);
nf_reset(skb);
+ nf_reset_trace(skb);
return netif_rx(skb);
}
EXPORT_SYMBOL_GPL(dev_forward_skb);