From: Daniel Borkmann daniel@iogearbox.net
[ Upstream commit e4400bbf5b15750e1b59bf4722d18d99be60c69f ]
The NTF_EXT_LEARNED neigh flag is usually propagated back to user space upon dump of the neighbor table. However, when used in combination with NTF_USE flag this is not the case despite exempting the entry from the garbage collector. This results in inconsistent state since entries are typically marked in neigh->flags with NTF_EXT_LEARNED, but here they are not. Fix it by propagating the creation flag to ___neigh_create().
Before fix:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a REACHABLE [...]
After fix:
# ./ip/ip n replace 192.168.178.30 dev enp5s0 use extern_learn # ./ip/ip n 192.168.178.30 dev enp5s0 lladdr f4:8c:50:5e:71:9a extern_learn REACHABLE [...]
Fixes: 9ce33e46531d ("neighbour: support for NTF_EXT_LEARNED flag") Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Roopa Prabhu roopa@nvidia.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/neighbour.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 2d5bc3a75faec..8457d5f97022b 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -379,7 +379,7 @@ EXPORT_SYMBOL(neigh_ifdown);
static struct neighbour *neigh_alloc(struct neigh_table *tbl, struct net_device *dev, - bool exempt_from_gc) + u8 flags, bool exempt_from_gc) { struct neighbour *n = NULL; unsigned long now = jiffies; @@ -412,6 +412,7 @@ do_alloc: n->updated = n->used = now; n->nud_state = NUD_NONE; n->output = neigh_blackhole; + n->flags = flags; seqlock_init(&n->hh.hh_lock); n->parms = neigh_parms_clone(&tbl->parms); timer_setup(&n->timer, neigh_timer_handler, 0); @@ -575,19 +576,18 @@ struct neighbour *neigh_lookup_nodev(struct neigh_table *tbl, struct net *net, } EXPORT_SYMBOL(neigh_lookup_nodev);
-static struct neighbour *___neigh_create(struct neigh_table *tbl, - const void *pkey, - struct net_device *dev, - bool exempt_from_gc, bool want_ref) +static struct neighbour * +___neigh_create(struct neigh_table *tbl, const void *pkey, + struct net_device *dev, u8 flags, + bool exempt_from_gc, bool want_ref) { - struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, exempt_from_gc); - u32 hash_val; - unsigned int key_len = tbl->key_len; - int error; + u32 hash_val, key_len = tbl->key_len; + struct neighbour *n1, *rc, *n; struct neigh_hash_table *nht; + int error;
+ n = neigh_alloc(tbl, dev, flags, exempt_from_gc); trace_neigh_create(tbl, dev, pkey, n, exempt_from_gc); - if (!n) { rc = ERR_PTR(-ENOBUFS); goto out; @@ -674,7 +674,7 @@ out_neigh_release: struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey, struct net_device *dev, bool want_ref) { - return ___neigh_create(tbl, pkey, dev, false, want_ref); + return ___neigh_create(tbl, pkey, dev, 0, false, want_ref); } EXPORT_SYMBOL(__neigh_create);
@@ -1942,7 +1942,9 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh,
exempt_from_gc = ndm->ndm_state & NUD_PERMANENT || ndm->ndm_flags & NTF_EXT_LEARNED; - neigh = ___neigh_create(tbl, dst, dev, exempt_from_gc, true); + neigh = ___neigh_create(tbl, dst, dev, + ndm->ndm_flags & NTF_EXT_LEARNED, + exempt_from_gc, true); if (IS_ERR(neigh)) { err = PTR_ERR(neigh); goto out;