[PATCH 3.18 10/45] ipv4: Map neigh lookup keys in __ipv4_neigh_lookup_noref()

From: Greg Kroah-Hartman
Date: Thu Feb 15 2018 - 10:18:47 EST


3.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Wang Han <wanghan1995315@xxxxxxxxx>

Commit 6c16fa957e84 is an incorrect backport as we map the keys in
struct __ipv4_neigh_lookup(), but the correct place to add the
code is struct __ipv4_neigh_lookup_noref(), compared to upstream.

Fix it by moving the code, or fewer cases will be covered as
__ipv4_neigh_lookup_noref() will be called unconditionally from
__ipv4_neigh_lookup(), and it can be called from other places
such as ip_output.c.

Fixes: 6c16fa957e84 (ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY)
Signed-off-by: Wang Han <wanghan1995315@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/arp.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -22,6 +22,9 @@ static inline struct neighbour *__ipv4_n
struct neighbour *n;
u32 hash_val;

+ if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
+ key = INADDR_ANY;
+
hash_val = arp_hashfn(key, dev, nht->hash_rnd[0]) >> (32 - nht->hash_shift);
for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
n != NULL;
@@ -37,9 +40,6 @@ static inline struct neighbour *__ipv4_n
{
struct neighbour *n;

- if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
- key = INADDR_ANY;
-
rcu_read_lock_bh();
n = __ipv4_neigh_lookup_noref(dev, key);
if (n && !atomic_inc_not_zero(&n->refcnt))