1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/passwordattr-interface.c b/drivers/platform/x86/dell/dell-wmi-sysman/passwordattr-interface.c
new file mode 100644
index 000000000000..5780b4d94759
--- /dev/null
+++ b/drivers/platform/x86/dell/dell-wmi-sysman/passwordattr-interface.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to SET password methods under BIOS attributes interface GUID
+ *
+ *  Copyright (c) 2020 Dell Inc.
+ */
+
+#include <linux/wmi.h>
+#include "dell-wmi-sysman.h"
+
+static int call_password_interface(struct wmi_device *wdev, char *in_args, size_t size)
+{
+	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+	struct acpi_buffer input;
+	union acpi_object *obj;
+	acpi_status status;
+	int ret = -EIO;
+
+	input.length =  (acpi_size) size;
+	input.pointer = in_args;
+	status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
+	if (ACPI_FAILURE(status))
+		return -EIO;
+	obj = (union acpi_object *)output.pointer;
+	if (obj->type == ACPI_TYPE_INTEGER)
+		ret = obj->integer.value;
+
+	kfree(output.pointer);
+	/* let userland know it may need to check is_password_set again */
+	kobject_uevent(&wmi_priv.class_dev->kobj, KOBJ_CHANGE);
+	return map_wmi_error(ret);
+}
+
+/**
+ * set_new_password() - Sets a system admin password
+ * @password_type: The type of password to set
+ * @new: The new password
+ *
+ * Sets the password using plaintext interface
+ */
+int set_new_password(const char *password_type, const char *new)
+{
+	size_t password_type_size, current_password_size, new_size;
+	size_t security_area_size, buffer_size;
+	char *buffer = NULL, *start;
+	char *current_password;
+	int ret;
+
+	mutex_lock(&wmi_priv.mutex);
+	if (!wmi_priv.password_attr_wdev) {
+		ret = -ENODEV;
+		goto out;
+	}
+	if (strcmp(password_type, "Admin") == 0) {
+		current_password = wmi_priv.current_admin_password;
+	} else if (strcmp(password_type, "System") == 0) {
+		current_password = wmi_priv.current_system_password;
+	} else {
+		ret = -EINVAL;
+		dev_err(&wmi_priv.password_attr_wdev->dev, "unknown password type %s\n",
+			password_type);
+		goto out;
+	}
+
+	/* build/calculate buffer */
+	security_area_size = calculate_security_buffer(wmi_priv.current_admin_password);
+	password_type_size = calculate_string_buffer(password_type);
+	current_password_size = calculate_string_buffer(current_password);
+	new_size = calculate_string_buffer(new);
+	buffer_size = security_area_size + password_type_size + current_password_size + new_size;
+	buffer = kzalloc(buffer_size, GFP_KERNEL);
+	if (!buffer) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* build security area */
+	populate_security_buffer(buffer, wmi_priv.current_admin_password);
+
+	/* build variables to set */
+	start = buffer + security_area_size;
+	ret = populate_string_buffer(start, password_type_size, password_type);
+	if (ret < 0)
+		goto out;
+
+	start += ret;
+	ret = populate_string_buffer(start, current_password_size, current_password);
+	if (ret < 0)
+		goto out;
+
+	start += ret;
+	ret = populate_string_buffer(start, new_size, new);
+	if (ret < 0)
+		goto out;
+
+	print_hex_dump_bytes("set new password data: ", DUMP_PREFIX_NONE, buffer, buffer_size);
+	ret = call_password_interface(wmi_priv.password_attr_wdev, buffer, buffer_size);
+	/* clear current_password here and use user input from wmi_priv.current_password */
+	if (!ret)
+		memset(current_password, 0, MAX_BUFF);
+	/* explain to user the detailed failure reason */
+	else if (ret == -EOPNOTSUPP)
+		dev_err(&wmi_priv.password_attr_wdev->dev, "admin password must be configured\n");
+	else if (ret == -EACCES)
+		dev_err(&wmi_priv.password_attr_wdev->dev, "invalid password\n");
+
+out:
+	kfree(buffer);
+	mutex_unlock(&wmi_priv.mutex);
+
+	return ret;
+}
+
+static int bios_attr_pass_interface_probe(struct wmi_device *wdev, const void *context)
+{
+	mutex_lock(&wmi_priv.mutex);
+	wmi_priv.password_attr_wdev = wdev;
+	mutex_unlock(&wmi_priv.mutex);
+	return 0;
+}
+
+static int bios_attr_pass_interface_remove(struct wmi_device *wdev)
+{
+	mutex_lock(&wmi_priv.mutex);
+	wmi_priv.password_attr_wdev = NULL;
+	mutex_unlock(&wmi_priv.mutex);
+	return 0;
+}
+
+static const struct wmi_device_id bios_attr_pass_interface_id_table[] = {
+	{ .guid_string = DELL_WMI_BIOS_PASSWORD_INTERFACE_GUID },
+	{ },
+};
+static struct wmi_driver bios_attr_pass_interface_driver = {
+	.driver = {
+		.name = DRIVER_NAME"-password"
+	},
+	.probe = bios_attr_pass_interface_probe,
+	.remove = bios_attr_pass_interface_remove,
+	.id_table = bios_attr_pass_interface_id_table,
+};
+
+int init_bios_attr_pass_interface(void)
+{
+	return wmi_driver_register(&bios_attr_pass_interface_driver);
+}
+
+void exit_bios_attr_pass_interface(void)
+{
+	wmi_driver_unregister(&bios_attr_pass_interface_driver);
+}
+
+MODULE_DEVICE_TABLE(wmi, bios_attr_pass_interface_id_table);