serial: initialize retinfo in uart_get_info()

If this check ever triggers

	static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
	{

		uport = uart_port_check(state);
	        if (!uport)
	                goto out;

then all those sysfs users will print stack contents to userspace.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: https://lore.kernel.org/r/967b9ef1-fb36-48bf-9e6a-1b99af24c052@p183
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 70bf2bec875c5ccad0c25cc5a79440584d48f2a9..be74d30cfa9e73a00999d90fc3b423f6db85acb2 100644 (file)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -775,6 +775,9 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
        struct uart_port *uport;
        int ret = -ENODEV;
 
+       /* Initialize structure in case we error out later to prevent any stack info leakage. */
+       *retinfo = (struct serial_struct){};
+
        /*
         * Ensure the state we copy is consistent and no hardware changes
         * occur as we go