greybus: operation: fix outgoing-response corruption

Fix potential corruption of outgoing responses by verifying that the
operations is indeed outgoing when receiving a response.

Failure to do so could lead to an incoming response corrupting an
outgoing response that uses the same operation id.

Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/operation.c b/drivers/staging/greybus/operation.c
index 8f99c8e..8539462 100644 (file)
--- a/drivers/staging/greybus/operation.c
+++ b/drivers/staging/greybus/operation.c
@@ -115,11 +115,11 @@ int gb_operation_result(struct gb_operation *operation)
 EXPORT_SYMBOL_GPL(gb_operation_result);
 
 /*
- * Looks up an operation on a connection and returns a refcounted pointer if
- * found, or NULL otherwise.
+ * Looks up an outgoing operation on a connection and returns a refcounted
+ * pointer if found, or NULL otherwise.
  */
 static struct gb_operation *
-gb_operation_find(struct gb_connection *connection, u16 operation_id)
+gb_operation_find_outgoing(struct gb_connection *connection, u16 operation_id)
 {
        struct gb_operation *operation;
        unsigned long flags;
@@ -127,7 +127,8 @@ gb_operation_find(struct gb_connection *connection, u16 operation_id)
 
        spin_lock_irqsave(&gb_operations_lock, flags);
        list_for_each_entry(operation, &connection->operations, links)
-               if (operation->id == operation_id) {
+               if (operation->id == operation_id &&
+                               !gb_operation_is_incoming(operation)) {
                        gb_operation_get(operation);
                        found = true;
                        break;
@@ -778,7 +779,7 @@ static void gb_connection_recv_response(struct gb_connection *connection,
        int errno = gb_operation_status_map(result);
        size_t message_size;
 
-       operation = gb_operation_find(connection, operation_id);
+       operation = gb_operation_find_outgoing(connection, operation_id);
        if (!operation) {
                dev_err(&connection->dev, "operation not found\n");
                return;