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>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ae13ef6b3ea7..395c15b82087 100644
--- 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);