xfrm: Assign esn pointers when cloning a state

When we clone a xfrm state we have to assign the replay_esn
and the preplay_esn pointers to the state if we use the
new replay detection method. To this end, we add a
xfrm_replay_clone() function that allocates memory for
the replay detection and takes over the necessary values
from the original state.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -1601,6 +1601,28 @@ static inline int xfrm_replay_state_esn_len(struct xfrm_replay_state_esn *replay
 }
 
 #ifdef CONFIG_XFRM_MIGRATE
+static inline int xfrm_replay_clone(struct xfrm_state *x,
+				     struct xfrm_state *orig)
+{
+	x->replay_esn = kzalloc(xfrm_replay_state_esn_len(orig->replay_esn),
+				GFP_KERNEL);
+	if (!x->replay_esn)
+		return -ENOMEM;
+
+	x->replay_esn->bmp_len = orig->replay_esn->bmp_len;
+	x->replay_esn->replay_window = orig->replay_esn->replay_window;
+
+	x->preplay_esn = kmemdup(x->replay_esn,
+				 xfrm_replay_state_esn_len(x->replay_esn),
+				 GFP_KERNEL);
+	if (!x->preplay_esn) {
+		kfree(x->replay_esn);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
 static inline struct xfrm_algo *xfrm_algo_clone(struct xfrm_algo *orig)
 {
 	return kmemdup(orig, xfrm_alg_len(orig), GFP_KERNEL);

net/xfrm/xfrm_state.c

@@ -1181,6 +1181,12 @@ static struct xfrm_state *xfrm_state_clone(struct xfrm_state *orig, int *errp)
 			goto error;
 	}
 
+	if (orig->replay_esn) {
+		err = xfrm_replay_clone(x, orig);
+		if (err)
+			goto error;
+	}
+
 	memcpy(&x->mark, &orig->mark, sizeof(x->mark));
 
 	err = xfrm_init_state(x);