rxrpc: Extract the code from a received ABORT packet much earlier

Extract the code from a received rx ABORT packet much earlier and in a
single place and harmonise the responses to malformed ABORT packets.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

net/rxrpc/conn_event.c

@@ -282,8 +282,6 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 			       u32 *_abort_code)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	__be32 wtmp;
-	u32 abort_code;
 	int loop, ret;
 
 	if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
@@ -305,16 +303,8 @@ static int rxrpc_process_event(struct rxrpc_connection *conn,
 		return 0;
 
 	case RXRPC_PACKET_TYPE_ABORT:
-		if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
-				  &wtmp, sizeof(wtmp)) < 0) {
-			trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
-					      tracepoint_string("bad_abort"));
-			return -EPROTO;
-		}
-		abort_code = ntohl(wtmp);
-
 		conn->error = -ECONNABORTED;
-		conn->abort_code = abort_code;
+		conn->abort_code = skb->priority;
 		conn->state = RXRPC_CONN_REMOTELY_ABORTED;
 		set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
 		rxrpc_abort_calls(conn, RXRPC_CALL_REMOTELY_ABORTED, sp->hdr.serial);

net/rxrpc/input.c

@@ -1019,20 +1019,11 @@ static void rxrpc_input_ackall(struct rxrpc_call *call, struct sk_buff *skb)
 static void rxrpc_input_abort(struct rxrpc_call *call, struct sk_buff *skb)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-	__be32 wtmp;
-	u32 abort_code = RX_CALL_DEAD;
-
-	_enter("");
-
-	if (skb->len >= 4 &&
-	    skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
-			  &wtmp, sizeof(wtmp)) >= 0)
-		abort_code = ntohl(wtmp);
 
-	trace_rxrpc_rx_abort(call, sp->hdr.serial, abort_code);
+	trace_rxrpc_rx_abort(call, sp->hdr.serial, skb->priority);
 
 	rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
-				  abort_code, -ECONNABORTED);
+				  skb->priority, -ECONNABORTED);
 }
 
 /*
@@ -1193,6 +1184,20 @@ int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
 	return 0;
 }
 
+/*
+ * Extract the abort code from an ABORT packet and stash it in skb->priority.
+ */
+static bool rxrpc_extract_abort(struct sk_buff *skb)
+{
+	__be32 wtmp;
+
+	if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
+			  &wtmp, sizeof(wtmp)) < 0)
+		return false;
+	skb->priority = ntohl(wtmp);
+	return true;
+}
+
 /*
  * handle data received on the local endpoint
  * - may be called in interrupt context
@@ -1264,8 +1269,10 @@ int rxrpc_input_packet(struct sock *udp_sk, struct sk_buff *skb)
 	case RXRPC_PACKET_TYPE_ACKALL:
 		if (sp->hdr.callNumber == 0)
 			goto bad_message;
-		fallthrough;
+		break;
 	case RXRPC_PACKET_TYPE_ABORT:
+		if (!rxrpc_extract_abort(skb))
+			return true; /* Just discard if malformed */
 		break;
 
 	case RXRPC_PACKET_TYPE_DATA: