[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/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 ssize_t trigger_custom_fallback_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' using custom fallback mechanism\n", name);

	mutex_lock(&test_fw_mutex);
	release_firmware(test_firmware);
	test_firmware = NULL;
	rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG, 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_custom_fallback);

#define TEST_FW_DEV_ATTR(name)          &dev_attr_##name.attr

static struct attribute *test_dev_attrs[] = {
	TEST_FW_DEV_ATTR(trigger_request),
	TEST_FW_DEV_ATTR(trigger_async_request),
	TEST_FW_DEV_ATTR(trigger_custom_fallback),
	NULL,
};

ATTRIBUTE_GROUPS(test_dev);

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

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;
	}

	pr_warn("interface ready\n");

	return 0;
}

module_init(test_firmware_init);

static void __exit test_firmware_exit(void)
{
	release_firmware(test_firmware);
	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>
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
061132d2 LR	129	static ssize_t trigger_custom_fallback_store(struct device *dev,
	130	struct device_attribute *attr,
	131	const char *buf, size_t count)
	132	{
	133	int rc;
	134	char *name;
	135
	136	name = kstrndup(buf, count, GFP_KERNEL);
	137	if (!name)
	138	return -ENOSPC;
	139
	140	pr_info("loading '%s' using custom fallback mechanism\n", name);
	141
	142	mutex_lock(&test_fw_mutex);
	143	release_firmware(test_firmware);
	144	test_firmware = NULL;
	145	rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOHOTPLUG, name,
	146	dev, GFP_KERNEL, NULL,
	147	trigger_async_request_cb);
	148	if (rc) {
	149	pr_info("async load of '%s' failed: %d\n", name, rc);
	150	kfree(name);
	151	goto out;
	152	}
	153	/* Free 'name' ASAP, to test for race conditions */
	154	kfree(name);
	155
	156	wait_for_completion(&async_fw_done);
	157
	158	if (test_firmware) {
	159	pr_info("loaded: %zu\n", test_firmware->size);
	160	rc = count;
	161	} else {
	162	pr_err("failed to async load firmware\n");
	163	rc = -ENODEV;
	164	}
	165
	166	out:
	167	mutex_unlock(&test_fw_mutex);
	168
	169	return rc;
	170	}
	171	static DEVICE_ATTR_WO(trigger_custom_fallback);
	172
083a93b0 LR	173	#define TEST_FW_DEV_ATTR(name) &dev_attr_##name.attr
	174
	175	static struct attribute *test_dev_attrs[] = {
	176	TEST_FW_DEV_ATTR(trigger_request),
	177	TEST_FW_DEV_ATTR(trigger_async_request),
061132d2	178	TEST_FW_DEV_ATTR(trigger_custom_fallback),
083a93b0 LR	179	NULL,
	180	};
	181
	182	ATTRIBUTE_GROUPS(test_dev);
	183
67fd553c LR	184	static struct miscdevice test_fw_misc_device = {
	185	.minor = MISC_DYNAMIC_MINOR,
	186	.name = "test_firmware",
	187	.fops = &test_fw_fops,
083a93b0	188	.groups = test_dev_groups,
67fd553c LR	189	};
67fd553c LR	190
0a8adf58 KC	191	static int __init test_firmware_init(void)
	192	{
	193	int rc;
	194
	195	rc = misc_register(&test_fw_misc_device);
	196	if (rc) {
	197	pr_err("could not register misc device: %d\n", rc);
	198	return rc;
	199	}
eb910947	200
0a8adf58 KC	201	pr_warn("interface ready\n");
	202
	203	return 0;
0a8adf58 KC	204	}
	205
	206	module_init(test_firmware_init);
	207
	208	static void __exit test_firmware_exit(void)
	209	{
	210	release_firmware(test_firmware);
0a8adf58 KC	211	misc_deregister(&test_fw_misc_device);
	212	pr_warn("removed interface\n");
	213	}
	214
	215	module_exit(test_firmware_exit);
	216
	217	MODULE_AUTHOR("Kees Cook <[email protected]>");
	218	MODULE_LICENSE("GPL");