1 files changed, 20 insertions, 10 deletions

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 9128aa0e40aa..c2c35cf4e308 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -837,7 +837,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 		u8 acks[RXRPC_MAXACKS];
 	} buf;
 	rxrpc_serial_t acked_serial;
-	rxrpc_seq_t first_soft_ack, hard_ack;
+	rxrpc_seq_t first_soft_ack, hard_ack, prev_pkt;
 	int nr_acks, offset, ioffset;
 
 	_enter("");
@@ -851,13 +851,14 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 
 	acked_serial = ntohl(buf.ack.serial);
 	first_soft_ack = ntohl(buf.ack.firstPacket);
+	prev_pkt = ntohl(buf.ack.previousPacket);
 	hard_ack = first_soft_ack - 1;
 	nr_acks = buf.ack.nAcks;
 	summary.ack_reason = (buf.ack.reason < RXRPC_ACK__INVALID ?
 			      buf.ack.reason : RXRPC_ACK__INVALID);
 
 	trace_rxrpc_rx_ack(call, sp->hdr.serial, acked_serial,
-			   first_soft_ack, ntohl(buf.ack.previousPacket),
+			   first_soft_ack, prev_pkt,
 			   summary.ack_reason, nr_acks);
 
 	if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
@@ -878,8 +879,9 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 				  rxrpc_propose_ack_respond_to_ack);
 	}
 
-	/* Discard any out-of-order or duplicate ACKs. */
-	if (before_eq(sp->hdr.serial, call->acks_latest))
+	/* Discard any out-of-order or duplicate ACKs (outside lock). */
+	if (before(first_soft_ack, call->ackr_first_seq) ||
+	    before(prev_pkt, call->ackr_prev_seq))
 		return;
 
 	buf.info.rxMTU = 0;
@@ -890,12 +892,16 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
 
 	spin_lock(&call->input_lock);
 
-	/* Discard any out-of-order or duplicate ACKs. */
-	if (before_eq(sp->hdr.serial, call->acks_latest))
+	/* Discard any out-of-order or duplicate ACKs (inside lock). */
+	if (before(first_soft_ack, call->ackr_first_seq) ||
+	    before(prev_pkt, call->ackr_prev_seq))
 		goto out;
 	call->acks_latest_ts = skb->tstamp;
 	call->acks_latest = sp->hdr.serial;
 
+	call->ackr_first_seq = first_soft_ack;
+	call->ackr_prev_seq = prev_pkt;
+
 	/* Parse rwind and mtu sizes if provided. */
 	if (buf.info.rxMTU)
 		rxrpc_input_ackinfo(call, skb, &buf.info);
@@ -1155,19 +1161,19 @@ int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
  * handle data received on the local endpoint
  * - may be called in interrupt context
  *
- * The socket is locked by the caller and this prevents the socket from being
- * shut down and the local endpoint from going away, thus sk_user_data will not
- * be cleared until this function returns.
+ * [!] Note that as this is called from the encap_rcv hook, the socket is not
+ * held locked by the caller and nothing prevents sk_user_data on the UDP from
+ * being cleared in the middle of processing this function.
  *
  * Called with the RCU read lock held from the IP layer via UDP.
  */
 int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
 {
+	struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
 	struct rxrpc_connection *conn;
 	struct rxrpc_channel *chan;
 	struct rxrpc_call *call = NULL;
 	struct rxrpc_skb_priv *sp;
-	struct rxrpc_local *local = udp_sk->sk_user_data;
 	struct rxrpc_peer *peer = NULL;
 	struct rxrpc_sock *rx = NULL;
 	unsigned int channel;
@@ -1175,6 +1181,10 @@ int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
 
 	_enter("%p", udp_sk);
 
+	if (unlikely(!local)) {
+		kfree_skb(skb);
+		return 0;
+	}
 	if (skb->tstamp == 0)
 		skb->tstamp = ktime_get_real();