[PATCH net-next 1/2] net: qrtr: Prevent stale ports from sending

[Sricharan Ramabadhran]

From: Vignesh Viswanathan <quic_viswanat@xxxxxxxxxxx>

If qrtr and some other process try to bind to the QMI Control port at
the same time, NEW_SERVER might come before ENETRESET is given to the
socket. This might cause a socket down/up when ENETRESET is received as
per the protocol and this triggers a DEL_SERVER and a second NEW_SERVER.

In order to prevent such messages from stale sockets being sent, check
if ENETRESET has been set on the socket and drop the packet.

Signed-off-by: Chris Lew <quic_clew@xxxxxxxxxxx>
Signed-off-by: Vignesh Viswanathan <quic_viswanat@xxxxxxxxxxx>
---
 net/qrtr/af_qrtr.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/net/qrtr/af_qrtr.c b/net/qrtr/af_qrtr.c
index 41ece61..26197a0 100644
--- a/net/qrtr/af_qrtr.c
+++ b/net/qrtr/af_qrtr.c
@@ -851,6 +851,7 @@ static int qrtr_local_enqueue(struct qrtr_node *node, struct sk_buff *skb,
 {
 	struct qrtr_sock *ipc;
 	struct qrtr_cb *cb;
+	struct sock *sk = skb->sk;
 
 	ipc = qrtr_port_lookup(to->sq_port);
 	if (!ipc || &ipc->sk == skb->sk) { /* do not send to self */
@@ -860,6 +861,15 @@ static int qrtr_local_enqueue(struct qrtr_node *node, struct sk_buff *skb,
 		return -ENODEV;
 	}
 
+	/* Keep resetting NETRESET until socket is closed */
+	if (sk && sk->sk_err == ENETRESET) {
+		sk->sk_err = ENETRESET;
+		sk_error_report(sk);
+		qrtr_port_put(ipc);
+		kfree_skb(skb);
+		return 0;
+	}
+
 	cb = (struct qrtr_cb *)skb->cb;
 	cb->src_node = from->sq_node;
 	cb->src_port = from->sq_port;
-- 
2.7.4