| 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");
|