xfrm: Copy policy family in clone_policy

[ Upstream commit 0e74aa1d79a5bbc663e03a2804399cae418a0321 ]

The syzbot found an ancient bug in the IPsec code.  When we cloned
a socket policy (for example, for a child TCP socket derived from a
listening socket), we did not copy the family field.  This results
in a live policy with a zero family field.  This triggers a BUG_ON
check in the af_key code when the cloned policy is retrieved.

This patch fixes it by copying the family field over.

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 8ce5711..f19e6a5 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1393,6 +1393,7 @@
 		newp->xfrm_nr = old->xfrm_nr;
 		newp->index = old->index;
 		newp->type = old->type;
+		newp->family = old->family;
 		memcpy(newp->xfrm_vec, old->xfrm_vec,
 		       newp->xfrm_nr*sizeof(struct xfrm_tmpl));