5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jeremy Kerr <jk@xxxxxxxxxxxxxxxxxxxx>
[ Upstream commit 1f6c77ac9e6ecef152fd5df94c4b3c346adb197a ]
We may need to receive packets addressed to the null EID (==0), but
addressed to us at the physical layer.
This change adds a lookup for local routes when we see a packet
addressed to EID 0, and a local phys address.
Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: 5093bbfc10ab ("mctp: perform route lookups under a RCU read-side lock")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/mctp/route.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/net/mctp/route.c b/net/mctp/route.c
index 89e67399249b4..859f57fd3871f 100644
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -480,6 +480,10 @@ static int mctp_alloc_local_tag(struct mctp_sock *msk,
int rc = -EAGAIN;
u8 tagbits;
+ /* for NULL destination EIDs, we may get a response from any peer */
+ if (daddr == MCTP_ADDR_NULL)
+ daddr = MCTP_ADDR_ANY;
+
/* be optimistic, alloc now */
key = mctp_key_alloc(msk, saddr, daddr, 0, GFP_KERNEL);
if (!key)
@@ -558,6 +562,20 @@ struct mctp_route *mctp_route_lookup(struct net *net, unsigned int dnet,
return rt;
}
+static struct mctp_route *mctp_route_lookup_null(struct net *net,
+ struct net_device *dev)
+{
+ struct mctp_route *rt;
+
+ list_for_each_entry_rcu(rt, &net->mctp.routes, list) {
+ if (rt->dev->dev == dev && rt->type == RTN_LOCAL &&
+ refcount_inc_not_zero(&rt->refs))
+ return rt;
+ }
+
+ return NULL;
+}
+
/* sends a skb to rt and releases the route. */
int mctp_do_route(struct mctp_route *rt, struct sk_buff *skb)
{
@@ -853,6 +871,11 @@ static int mctp_pkttype_receive(struct sk_buff *skb, struct net_device *dev,
rcu_read_unlock();
rt = mctp_route_lookup(net, cb->net, mh->dest);
+
+ /* NULL EID, but addressed to our physical address */
+ if (!rt && mh->dest == MCTP_ADDR_NULL && skb->pkt_type == PACKET_HOST)
+ rt = mctp_route_lookup_null(net, dev);
+
if (!rt)
goto err_drop;
--
2.40.1
