net: Reset secmark when scrubbing packet

skb_scrub_packet() is called when a packet switches between a context
such as between underlay and overlay, between namespaces, or between
L3 subnets.

While we already scrub the packet mark, connection tracking entry,
and cached destination, the security mark/context is left intact.

It seems wrong to inherit the security context of a packet when going
from overlay to underlay or across forwarding paths.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ae13ef6..395c15b 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4148,6 +4148,7 @@ void skb_scrub_packet(struct sk_buff *skb, bool xnet)
        skb->ignore_df = 0;
        skb_dst_drop(skb);
        skb->mark = 0;
+       skb_init_secmark(skb);
        secpath_reset(skb);
        nf_reset(skb);
        nf_reset_trace(skb);