[mirror_ubuntu-artful-kernel.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/completion.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 ssize_t trigger_request_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	int rc;
	char *name;

	name = kstrndup(buf, count, GFP_KERNEL);
	if (!name)
		return -ENOSPC;

	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);
		goto out;
	}
	pr_info("loaded: %zu\n", test_firmware->size);
	rc = count;

out:
	mutex_unlock(&test_fw_mutex);

	kfree(name);

	return rc;
}
static DEVICE_ATTR_WO(trigger_request);

static DECLARE_COMPLETION(async_fw_done);

static void trigger_async_request_cb(const struct firmware *fw, void *context)
{
	test_firmware = fw;
	complete(&async_fw_done);
}

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

	name = kstrndup(buf, count, GFP_KERNEL);
	if (!name)
		return -ENOSPC;

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

	mutex_lock(&test_fw_mutex);
	release_firmware(test_firmware);
	test_firmware = NULL;
	rc = request_firmware_nowait(THIS_MODULE, 1, name, dev, GFP_KERNEL,
				     NULL, trigger_async_request_cb);
	if (rc) {
		pr_info("async load of '%s' failed: %d\n", name, rc);
		kfree(name);
		goto out;
	}
	/* Free 'name' ASAP, to test for race conditions */
	kfree(name);

	wait_for_completion(&async_fw_done);

	if (test_firmware) {
		pr_info("loaded: %zu\n", test_firmware->size);
		rc = count;
	} else {
		pr_err("failed to async load firmware\n");
		rc = -ENODEV;
	}

out:
	mutex_unlock(&test_fw_mutex);

	return rc;
}
static DEVICE_ATTR_WO(trigger_async_request);

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

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;
	}

	rc = device_create_file(test_fw_misc_device.this_device,
				&dev_attr_trigger_async_request);
	if (rc) {
		pr_err("could not create async sysfs interface: %d\n", rc);
		goto remove_file;
	}

	pr_warn("interface ready\n");

	return 0;

remove_file:
	device_remove_file(test_fw_misc_device.this_device,
			   &dev_attr_trigger_async_request);
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_async_request);
	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 <keescook@chromium.org>");
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>
eb910947	15	#include <linux/completion.h>
0a8adf58 KC	16	#include <linux/firmware.h>
	17	#include <linux/device.h>
	18	#include <linux/fs.h>
	19	#include <linux/miscdevice.h>
	20	#include <linux/slab.h>
	21	#include <linux/uaccess.h>
	22
	23	static DEFINE_MUTEX(test_fw_mutex);
	24	static const struct firmware *test_firmware;
	25
	26	static ssize_t test_fw_misc_read(struct file f, char __user buf,
	27	size_t size, loff_t *offset)
	28	{
	29	ssize_t rc = 0;
	30
	31	mutex_lock(&test_fw_mutex);
	32	if (test_firmware)
	33	rc = simple_read_from_buffer(buf, size, offset,
	34	test_firmware->data,
	35	test_firmware->size);
	36	mutex_unlock(&test_fw_mutex);
	37	return rc;
	38	}
	39
	40	static const struct file_operations test_fw_fops = {
	41	.owner = THIS_MODULE,
	42	.read = test_fw_misc_read,
	43	};
	44
0a8adf58 KC	45	static ssize_t trigger_request_store(struct device *dev,
	46	struct device_attribute *attr,
	47	const char *buf, size_t count)
	48	{
	49	int rc;
	50	char *name;
	51
be4a1326	52	name = kstrndup(buf, count, GFP_KERNEL);
0a8adf58 KC	53	if (!name)
0a8adf58 KC	54	return -ENOSPC;
0a8adf58 KC	55
	56	pr_info("loading '%s'\n", name);
	57
	58	mutex_lock(&test_fw_mutex);
	59	release_firmware(test_firmware);
	60	test_firmware = NULL;
	61	rc = request_firmware(&test_firmware, name, dev);
47e0bbb7	62	if (rc) {
0a8adf58	63	pr_info("load of '%s' failed: %d\n", name, rc);
47e0bbb7 BN	64	goto out;
	65	}
	66	pr_info("loaded: %zu\n", test_firmware->size);
	67	rc = count;
	68
	69	out:
0a8adf58 KC	70	mutex_unlock(&test_fw_mutex);
	71
	72	kfree(name);
	73
47e0bbb7	74	return rc;
0a8adf58 KC	75	}
	76	static DEVICE_ATTR_WO(trigger_request);
	77
eb910947 BN	78	static DECLARE_COMPLETION(async_fw_done);
	79
	80	static void trigger_async_request_cb(const struct firmware fw, void context)
	81	{
	82	test_firmware = fw;
	83	complete(&async_fw_done);
	84	}
	85
	86	static ssize_t trigger_async_request_store(struct device *dev,
	87	struct device_attribute *attr,
	88	const char *buf, size_t count)
	89	{
	90	int rc;
	91	char *name;
	92
	93	name = kstrndup(buf, count, GFP_KERNEL);
	94	if (!name)
	95	return -ENOSPC;
	96
	97	pr_info("loading '%s'\n", name);
	98
	99	mutex_lock(&test_fw_mutex);
	100	release_firmware(test_firmware);
	101	test_firmware = NULL;
	102	rc = request_firmware_nowait(THIS_MODULE, 1, name, dev, GFP_KERNEL,
	103	NULL, trigger_async_request_cb);
	104	if (rc) {
	105	pr_info("async load of '%s' failed: %d\n", name, rc);
	106	kfree(name);
	107	goto out;
	108	}
	109	/* Free 'name' ASAP, to test for race conditions */
	110	kfree(name);
	111
	112	wait_for_completion(&async_fw_done);
	113
	114	if (test_firmware) {
	115	pr_info("loaded: %zu\n", test_firmware->size);
	116	rc = count;
	117	} else {
	118	pr_err("failed to async load firmware\n");
	119	rc = -ENODEV;
	120	}
	121
	122	out:
	123	mutex_unlock(&test_fw_mutex);
	124
	125	return rc;
	126	}
	127	static DEVICE_ATTR_WO(trigger_async_request);
	128
67fd553c LR	129	static struct miscdevice test_fw_misc_device = {
	130	.minor = MISC_DYNAMIC_MINOR,
	131	.name = "test_firmware",
	132	.fops = &test_fw_fops,
	133	};
	134
0a8adf58 KC	135	static int __init test_firmware_init(void)
	136	{
	137	int rc;
	138
	139	rc = misc_register(&test_fw_misc_device);
	140	if (rc) {
	141	pr_err("could not register misc device: %d\n", rc);
	142	return rc;
	143	}
	144	rc = device_create_file(test_fw_misc_device.this_device,
	145	&dev_attr_trigger_request);
	146	if (rc) {
	147	pr_err("could not create sysfs interface: %d\n", rc);
	148	goto dereg;
	149	}
	150
eb910947 BN	151	rc = device_create_file(test_fw_misc_device.this_device,
	152	&dev_attr_trigger_async_request);
	153	if (rc) {
	154	pr_err("could not create async sysfs interface: %d\n", rc);
	155	goto remove_file;
	156	}
	157
0a8adf58 KC	158	pr_warn("interface ready\n");
	159
	160	return 0;
eb910947 BN	161
	162	remove_file:
	163	device_remove_file(test_fw_misc_device.this_device,
	164	&dev_attr_trigger_async_request);
0a8adf58 KC	165	dereg:
	166	misc_deregister(&test_fw_misc_device);
	167	return rc;
	168	}
	169
	170	module_init(test_firmware_init);
	171
	172	static void __exit test_firmware_exit(void)
	173	{
	174	release_firmware(test_firmware);
eb910947 BN	175	device_remove_file(test_fw_misc_device.this_device,
eb910947 BN	176	&dev_attr_trigger_async_request);
0a8adf58 KC	177	device_remove_file(test_fw_misc_device.this_device,
	178	&dev_attr_trigger_request);
	179	misc_deregister(&test_fw_misc_device);
	180	pr_warn("removed interface\n");
	181	}
	182
	183	module_exit(test_firmware_exit);
	184
	185	MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
	186	MODULE_LICENSE("GPL");