greybus: uart: add max-payload sanity check
Let's be well behaved and add a sanity check on the maximum greybus
payload size to avoid underflow on the calculated buffer size.
Reviewed-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
index 52cc9d5..60617cb 100644
--- a/drivers/staging/greybus/uart.c
+++ b/drivers/staging/greybus/uart.c
@@ -587,6 +587,7 @@
static int gb_uart_connection_init(struct gb_connection *connection)
{
+ size_t max_payload;
struct gb_tty *gb_tty;
struct device *tty_dev;
int retval;
@@ -607,8 +608,13 @@
goto error_alloc;
}
- gb_tty->buffer_payload_max =
- gb_operation_get_payload_size_max(connection) -
+ max_payload = gb_operation_get_payload_size_max(connection);
+ if (max_payload < sizeof(struct gb_uart_send_data_request)) {
+ retval = -EINVAL;
+ goto error_payload;
+ }
+
+ gb_tty->buffer_payload_max = max_payload -
sizeof(struct gb_uart_send_data_request);
gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);