[linux.git] / lib / test_firmware.c

/*
 * This module provides an interface to trigger and test firmware loading.
 *
 * It is designed to be used for basic evaluation of the firmware loading
 * subsystem (for example when validating firmware verification). It lacks
 * any extra dependencies, and will not normally be loaded by the system
 * unless explicitly requested by name.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/firmware.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

static DEFINE_MUTEX(test_fw_mutex);
static const struct firmware *test_firmware;

static ssize_t test_fw_misc_read(struct file *f, char __user *buf,
				 size_t size, loff_t *offset)
{
	ssize_t rc = 0;

	mutex_lock(&test_fw_mutex);
	if (test_firmware)
		rc = simple_read_from_buffer(buf, size, offset,
					     test_firmware->data,
					     test_firmware->size);
	mutex_unlock(&test_fw_mutex);
	return rc;
}

static const struct file_operations test_fw_fops = {
	.owner          = THIS_MODULE,
	.read           = test_fw_misc_read,
};

static struct miscdevice test_fw_misc_device = {
	.minor          = MISC_DYNAMIC_MINOR,
	.name           = "test_firmware",
	.fops           = &test_fw_fops,
};

static ssize_t trigger_request_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	int rc;
	char *name;

	name = kzalloc(count + 1, GFP_KERNEL);
	if (!name)
		return -ENOSPC;
	memcpy(name, buf, count);

	pr_info("loading '%s'\n", name);

	mutex_lock(&test_fw_mutex);
	release_firmware(test_firmware);
	test_firmware = NULL;
	rc = request_firmware(&test_firmware, name, dev);
	if (rc)
		pr_info("load of '%s' failed: %d\n", name, rc);
	pr_info("loaded: %zu\n", test_firmware ? test_firmware->size : 0);
	mutex_unlock(&test_fw_mutex);

	kfree(name);

	return count;
}
static DEVICE_ATTR_WO(trigger_request);

static int __init test_firmware_init(void)
{
	int rc;

	rc = misc_register(&test_fw_misc_device);
	if (rc) {
		pr_err("could not register misc device: %d\n", rc);
		return rc;
	}
	rc = device_create_file(test_fw_misc_device.this_device,
				&dev_attr_trigger_request);
	if (rc) {
		pr_err("could not create sysfs interface: %d\n", rc);
		goto dereg;
	}

	pr_warn("interface ready\n");

	return 0;
dereg:
	misc_deregister(&test_fw_misc_device);
	return rc;
}

module_init(test_firmware_init);

static void __exit test_firmware_exit(void)
{
	release_firmware(test_firmware);
	device_remove_file(test_fw_misc_device.this_device,
			   &dev_attr_trigger_request);
	misc_deregister(&test_fw_misc_device);
	pr_warn("removed interface\n");
}

module_exit(test_firmware_exit);

MODULE_AUTHOR("Kees Cook <[email protected]>");
MODULE_LICENSE("GPL");
Commit	Line	Data
0a8adf58 KC	1	/*
	2	* This module provides an interface to trigger and test firmware loading.
	3	*
	4	* It is designed to be used for basic evaluation of the firmware loading
	5	* subsystem (for example when validating firmware verification). It lacks
	6	* any extra dependencies, and will not normally be loaded by the system
	7	* unless explicitly requested by name.
	8	*/
	9
	10	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	11
	12	#include <linux/init.h>
	13	#include <linux/module.h>
	14	#include <linux/printk.h>
	15	#include <linux/firmware.h>
	16	#include <linux/device.h>
	17	#include <linux/fs.h>
	18	#include <linux/miscdevice.h>
	19	#include <linux/slab.h>
	20	#include <linux/uaccess.h>
	21
	22	static DEFINE_MUTEX(test_fw_mutex);
	23	static const struct firmware *test_firmware;
	24
	25	static ssize_t test_fw_misc_read(struct file f, char __user buf,
	26	size_t size, loff_t *offset)
	27	{
	28	ssize_t rc = 0;
	29
	30	mutex_lock(&test_fw_mutex);
	31	if (test_firmware)
	32	rc = simple_read_from_buffer(buf, size, offset,
	33	test_firmware->data,
	34	test_firmware->size);
	35	mutex_unlock(&test_fw_mutex);
	36	return rc;
	37	}
	38
	39	static const struct file_operations test_fw_fops = {
	40	.owner = THIS_MODULE,
	41	.read = test_fw_misc_read,
	42	};
	43
	44	static struct miscdevice test_fw_misc_device = {
	45	.minor = MISC_DYNAMIC_MINOR,
	46	.name = "test_firmware",
	47	.fops = &test_fw_fops,
	48	};
	49
	50	static ssize_t trigger_request_store(struct device *dev,
	51	struct device_attribute *attr,
	52	const char *buf, size_t count)
	53	{
	54	int rc;
	55	char *name;
	56
	57	name = kzalloc(count + 1, GFP_KERNEL);
	58	if (!name)
	59	return -ENOSPC;
	60	memcpy(name, buf, count);
	61
	62	pr_info("loading '%s'\n", name);
	63
	64	mutex_lock(&test_fw_mutex);
65	release_firmware(test_firmware);
66	test_firmware = NULL;
67	rc = request_firmware(&test_firmware, name, dev);
68	if (rc)
69	pr_info("load of '%s' failed: %d\n", name, rc);
70	pr_info("loaded: %zu\n", test_firmware ? test_firmware->size : 0);
71	mutex_unlock(&test_fw_mutex);
72
73	kfree(name);
74
75	return count;
76	}
77	static DEVICE_ATTR_WO(trigger_request);
78
79	static int __init test_firmware_init(void)
80	{
81	int rc;
82
83	rc = misc_register(&test_fw_misc_device);
84	if (rc) {
85	pr_err("could not register misc device: %d\n", rc);
86	return rc;
87	}
88	rc = device_create_file(test_fw_misc_device.this_device,
89	&dev_attr_trigger_request);
90	if (rc) {
91	pr_err("could not create sysfs interface: %d\n", rc);
92	goto dereg;
93	}
94
95	pr_warn("interface ready\n");
96
97	return 0;
98	dereg:
99	misc_deregister(&test_fw_misc_device);
100	return rc;
101	}
102
103	module_init(test_firmware_init);
104
105	static void __exit test_firmware_exit(void)
106	{
107	release_firmware(test_firmware);
108	device_remove_file(test_fw_misc_device.this_device,
109	&dev_attr_trigger_request);
110	misc_deregister(&test_fw_misc_device);
111	pr_warn("removed interface\n");
112	}
113
114	module_exit(test_firmware_exit);
115
116	MODULE_AUTHOR("Kees Cook <[email protected]>");
117	MODULE_LICENSE("GPL");