From: Jim Westfall <jwestfall@surrealistic.net>
Date: Sun, 14 Jan 2018 04:18:50 -0800
Subject: net: Allow neigh contructor functions ability to modify the
 primary_key
Git-commit: 096b9854c04df86f03b38a97d40b6506e5730919
Patch-mainline: v4.15-rc9
References: networking-stable-18_01_28

Use n->primary_key instead of pkey to account for the possibility that a neigh
constructor function may have modified the primary_key value.

Signed-off-by: Jim Westfall <jwestfall@surrealistic.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 net/core/neighbour.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -533,7 +533,7 @@ struct neighbour *__neigh_create(struct
 	if (atomic_read(&tbl->entries) > (1 << nht->hash_shift))
 		nht = neigh_hash_grow(tbl, nht->hash_shift + 1);
 
-	hash_val = tbl->hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
+	hash_val = tbl->hash(n->primary_key, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
 
 	if (n->parms->dead) {
 		rc = ERR_PTR(-EINVAL);
@@ -545,7 +545,7 @@ struct neighbour *__neigh_create(struct
 	     n1 != NULL;
 	     n1 = rcu_dereference_protected(n1->next,
 			lockdep_is_held(&tbl->lock))) {
-		if (dev == n1->dev && !memcmp(n1->primary_key, pkey, key_len)) {
+		if (dev == n1->dev && !memcmp(n1->primary_key, n->primary_key, key_len)) {
 			if (want_ref)
 				neigh_hold(n1);
 			rc = n1;