Contributors: 34
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Michael Buesch |
733 |
29.63% |
2 |
3.77% |
| Rusty Russell |
365 |
14.75% |
5 |
9.43% |
| Torsten Duwe |
226 |
9.14% |
3 |
5.66% |
| Ian Molton |
205 |
8.29% |
2 |
3.77% |
| Dmitry Torokhov |
195 |
7.88% |
1 |
1.89% |
| PrasannaKumar Muralidharan |
176 |
7.11% |
2 |
3.77% |
| Herbert Xu |
129 |
5.21% |
6 |
11.32% |
| Harald Freudenberger |
120 |
4.85% |
2 |
3.77% |
| Amit Shah |
91 |
3.68% |
1 |
1.89% |
| Takashi Iwai |
40 |
1.62% |
1 |
1.89% |
| Satoru Takeuchi |
34 |
1.37% |
1 |
1.89% |
| Greg Kroah-Hartman |
23 |
0.93% |
1 |
1.89% |
| Corentin Labbe |
17 |
0.69% |
4 |
7.55% |
| Andrew Lutomirski |
16 |
0.65% |
1 |
1.89% |
| Jiri Slaby |
15 |
0.61% |
1 |
1.89% |
| Ralph Wuerthner |
14 |
0.57% |
1 |
1.89% |
| Gary R Hook |
14 |
0.57% |
1 |
1.89% |
| Kees Cook |
8 |
0.32% |
1 |
1.89% |
| Keith Packard |
8 |
0.32% |
1 |
1.89% |
| Amos Kong |
7 |
0.28% |
1 |
1.89% |
| Rickard Strandqvist |
7 |
0.28% |
1 |
1.89% |
| Kay Sievers |
5 |
0.20% |
2 |
3.77% |
| Arnd Bergmann |
5 |
0.20% |
1 |
1.89% |
| Rafael J. Wysocki |
4 |
0.16% |
1 |
1.89% |
| Ingo Molnar |
3 |
0.12% |
1 |
1.89% |
| Martin Schwidefsky |
2 |
0.08% |
1 |
1.89% |
| Stephen Boyd |
2 |
0.08% |
1 |
1.89% |
| Al Viro |
2 |
0.08% |
1 |
1.89% |
| Patrick McHardy |
2 |
0.08% |
1 |
1.89% |
| Michael S. Tsirkin |
2 |
0.08% |
1 |
1.89% |
| Arvind Yadav |
1 |
0.04% |
1 |
1.89% |
| Arjan van de Ven |
1 |
0.04% |
1 |
1.89% |
| Lee Jones |
1 |
0.04% |
1 |
1.89% |
| Linus Torvalds |
1 |
0.04% |
1 |
1.89% |
| Total |
2474 |
|
53 |
|
/*
* hw_random/core.c: HWRNG core API
*
* Copyright 2006 Michael Buesch <m@bues.ch>
* Copyright 2005 (c) MontaVista Software, Inc.
*
* Please read Documentation/hw_random.txt for details on use.
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/hw_random.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/sched/signal.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#define RNG_MODULE_NAME "hw_random"
static struct hwrng *current_rng;
/* the current rng has been explicitly chosen by user via sysfs */
static int cur_rng_set_by_user;
static struct task_struct *hwrng_fill;
/* list of registered rngs, sorted decending by quality */
static LIST_HEAD(rng_list);
/* Protects rng_list and current_rng */
static DEFINE_MUTEX(rng_mutex);
/* Protects rng read functions, data_avail, rng_buffer and rng_fillbuf */
static DEFINE_MUTEX(reading_mutex);
static int data_avail;
static u8 *rng_buffer, *rng_fillbuf;
static unsigned short current_quality;
static unsigned short default_quality; /* = 0; default to "off" */
module_param(current_quality, ushort, 0644);
MODULE_PARM_DESC(current_quality,
"current hwrng entropy estimation per 1024 bits of input");
module_param(default_quality, ushort, 0644);
MODULE_PARM_DESC(default_quality,
"default entropy content of hwrng per 1024 bits of input");
static void drop_current_rng(void);
static int hwrng_init(struct hwrng *rng);
static void start_khwrngd(void);
static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
int wait);
static size_t rng_buffer_size(void)
{
return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
}
static void add_early_randomness(struct hwrng *rng)
{
int bytes_read;
size_t size = min_t(size_t, 16, rng_buffer_size());
mutex_lock(&reading_mutex);
bytes_read = rng_get_data(rng, rng_buffer, size, 1);
mutex_unlock(&reading_mutex);
if (bytes_read > 0)
add_device_randomness(rng_buffer, bytes_read);
}
static inline void cleanup_rng(struct kref *kref)
{
struct hwrng *rng = container_of(kref, struct hwrng, ref);
if (rng->cleanup)
rng->cleanup(rng);
complete(&rng->cleanup_done);
}
static int set_current_rng(struct hwrng *rng)
{
int err;
BUG_ON(!mutex_is_locked(&rng_mutex));
err = hwrng_init(rng);
if (err)
return err;
drop_current_rng();
current_rng = rng;
return 0;
}
static void drop_current_rng(void)
{
BUG_ON(!mutex_is_locked(&rng_mutex));
if (!current_rng)
return;
/* decrease last reference for triggering the cleanup */
kref_put(¤t_rng->ref, cleanup_rng);
current_rng = NULL;
}
/* Returns ERR_PTR(), NULL or refcounted hwrng */
static struct hwrng *get_current_rng(void)
{
struct hwrng *rng;
if (mutex_lock_interruptible(&rng_mutex))
return ERR_PTR(-ERESTARTSYS);
rng = current_rng;
if (rng)
kref_get(&rng->ref);
mutex_unlock(&rng_mutex);
return rng;
}
static void put_rng(struct hwrng *rng)
{
/*
* Hold rng_mutex here so we serialize in case they set_current_rng
* on rng again immediately.
*/
mutex_lock(&rng_mutex);
if (rng)
kref_put(&rng->ref, cleanup_rng);
mutex_unlock(&rng_mutex);
}
static int hwrng_init(struct hwrng *rng)
{
if (kref_get_unless_zero(&rng->ref))
goto skip_init;
if (rng->init) {
int ret;
ret = rng->init(rng);
if (ret)
return ret;
}
kref_init(&rng->ref);
reinit_completion(&rng->cleanup_done);
skip_init:
add_early_randomness(rng);
current_quality = rng->quality ? : default_quality;
if (current_quality > 1024)
current_quality = 1024;
if (current_quality == 0 && hwrng_fill)
kthread_stop(hwrng_fill);
if (current_quality > 0 && !hwrng_fill)
start_khwrngd();
return 0;
}
static int rng_dev_open(struct inode *inode, struct file *filp)
{
/* enforce read-only access to this chrdev */
if ((filp->f_mode & FMODE_READ) == 0)
return -EINVAL;
if (filp->f_mode & FMODE_WRITE)
return -EINVAL;
return 0;
}
static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
int wait) {
int present;
BUG_ON(!mutex_is_locked(&reading_mutex));
if (rng->read)
return rng->read(rng, (void *)buffer, size, wait);
if (rng->data_present)
present = rng->data_present(rng, wait);
else
present = 1;
if (present)
return rng->data_read(rng, (u32 *)buffer);
return 0;
}
static ssize_t rng_dev_read(struct file *filp, char __user *buf,
size_t size, loff_t *offp)
{
ssize_t ret = 0;
int err = 0;
int bytes_read, len;
struct hwrng *rng;
while (size) {
rng = get_current_rng();
if (IS_ERR(rng)) {
err = PTR_ERR(rng);
goto out;
}
if (!rng) {
err = -ENODEV;
goto out;
}
if (mutex_lock_interruptible(&reading_mutex)) {
err = -ERESTARTSYS;
goto out_put;
}
if (!data_avail) {
bytes_read = rng_get_data(rng, rng_buffer,
rng_buffer_size(),
!(filp->f_flags & O_NONBLOCK));
if (bytes_read < 0) {
err = bytes_read;
goto out_unlock_reading;
}
data_avail = bytes_read;
}
if (!data_avail) {
if (filp->f_flags & O_NONBLOCK) {
err = -EAGAIN;
goto out_unlock_reading;
}
} else {
len = data_avail;
if (len > size)
len = size;
data_avail -= len;
if (copy_to_user(buf + ret, rng_buffer + data_avail,
len)) {
err = -EFAULT;
goto out_unlock_reading;
}
size -= len;
ret += len;
}
mutex_unlock(&reading_mutex);
put_rng(rng);
if (need_resched())
schedule_timeout_interruptible(1);
if (signal_pending(current)) {
err = -ERESTARTSYS;
goto out;
}
}
out:
return ret ? : err;
out_unlock_reading:
mutex_unlock(&reading_mutex);
out_put:
put_rng(rng);
goto out;
}
static const struct file_operations rng_chrdev_ops = {
.owner = THIS_MODULE,
.open = rng_dev_open,
.read = rng_dev_read,
.llseek = noop_llseek,
};
static const struct attribute_group *rng_dev_groups[];
static struct miscdevice rng_miscdev = {
.minor = HWRNG_MINOR,
.name = RNG_MODULE_NAME,
.nodename = "hwrng",
.fops = &rng_chrdev_ops,
.groups = rng_dev_groups,
};
static int enable_best_rng(void)
{
int ret = -ENODEV;
BUG_ON(!mutex_is_locked(&rng_mutex));
/* rng_list is sorted by quality, use the best (=first) one */
if (!list_empty(&rng_list)) {
struct hwrng *new_rng;
new_rng = list_entry(rng_list.next, struct hwrng, list);
ret = ((new_rng == current_rng) ? 0 : set_current_rng(new_rng));
if (!ret)
cur_rng_set_by_user = 0;
} else {
drop_current_rng();
cur_rng_set_by_user = 0;
ret = 0;
}
return ret;
}
static ssize_t hwrng_attr_current_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
int err = -ENODEV;
struct hwrng *rng;
err = mutex_lock_interruptible(&rng_mutex);
if (err)
return -ERESTARTSYS;
if (sysfs_streq(buf, "")) {
err = enable_best_rng();
} else {
list_for_each_entry(rng, &rng_list, list) {
if (sysfs_streq(rng->name, buf)) {
cur_rng_set_by_user = 1;
err = set_current_rng(rng);
break;
}
}
}
mutex_unlock(&rng_mutex);
return err ? : len;
}
static ssize_t hwrng_attr_current_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
ssize_t ret;
struct hwrng *rng;
rng = get_current_rng();
if (IS_ERR(rng))
return PTR_ERR(rng);
ret = snprintf(buf, PAGE_SIZE, "%s\n", rng ? rng->name : "none");
put_rng(rng);
return ret;
}
static ssize_t hwrng_attr_available_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
int err;
struct hwrng *rng;
err = mutex_lock_interruptible(&rng_mutex);
if (err)
return -ERESTARTSYS;
buf[0] = '\0';
list_for_each_entry(rng, &rng_list, list) {
strlcat(buf, rng->name, PAGE_SIZE);
strlcat(buf, " ", PAGE_SIZE);
}
strlcat(buf, "\n", PAGE_SIZE);
mutex_unlock(&rng_mutex);
return strlen(buf);
}
static ssize_t hwrng_attr_selected_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return snprintf(buf, PAGE_SIZE, "%d\n", cur_rng_set_by_user);
}
static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR,
hwrng_attr_current_show,
hwrng_attr_current_store);
static DEVICE_ATTR(rng_available, S_IRUGO,
hwrng_attr_available_show,
NULL);
static DEVICE_ATTR(rng_selected, S_IRUGO,
hwrng_attr_selected_show,
NULL);
static struct attribute *rng_dev_attrs[] = {
&dev_attr_rng_current.attr,
&dev_attr_rng_available.attr,
&dev_attr_rng_selected.attr,
NULL
};
ATTRIBUTE_GROUPS(rng_dev);
static void __exit unregister_miscdev(void)
{
misc_deregister(&rng_miscdev);
}
static int __init register_miscdev(void)
{
return misc_register(&rng_miscdev);
}
static int hwrng_fillfn(void *unused)
{
long rc;
while (!kthread_should_stop()) {
struct hwrng *rng;
rng = get_current_rng();
if (IS_ERR(rng) || !rng)
break;
mutex_lock(&reading_mutex);
rc = rng_get_data(rng, rng_fillbuf,
rng_buffer_size(), 1);
mutex_unlock(&reading_mutex);
put_rng(rng);
if (rc <= 0) {
pr_warn("hwrng: no data available\n");
msleep_interruptible(10000);
continue;
}
/* Outside lock, sure, but y'know: randomness. */
add_hwgenerator_randomness((void *)rng_fillbuf, rc,
rc * current_quality * 8 >> 10);
}
hwrng_fill = NULL;
return 0;
}
static void start_khwrngd(void)
{
hwrng_fill = kthread_run(hwrng_fillfn, NULL, "hwrng");
if (IS_ERR(hwrng_fill)) {
pr_err("hwrng_fill thread creation failed\n");
hwrng_fill = NULL;
}
}
int hwrng_register(struct hwrng *rng)
{
int err = -EINVAL;
struct hwrng *old_rng, *tmp;
struct list_head *rng_list_ptr;
if (!rng->name || (!rng->data_read && !rng->read))
goto out;
mutex_lock(&rng_mutex);
/* Must not register two RNGs with the same name. */
err = -EEXIST;
list_for_each_entry(tmp, &rng_list, list) {
if (strcmp(tmp->name, rng->name) == 0)
goto out_unlock;
}
init_completion(&rng->cleanup_done);
complete(&rng->cleanup_done);
/* rng_list is sorted by decreasing quality */
list_for_each(rng_list_ptr, &rng_list) {
tmp = list_entry(rng_list_ptr, struct hwrng, list);
if (tmp->quality < rng->quality)
break;
}
list_add_tail(&rng->list, rng_list_ptr);
old_rng = current_rng;
err = 0;
if (!old_rng ||
(!cur_rng_set_by_user && rng->quality > old_rng->quality)) {
/*
* Set new rng as current as the new rng source
* provides better entropy quality and was not
* chosen by userspace.
*/
err = set_current_rng(rng);
if (err)
goto out_unlock;
}
if (old_rng && !rng->init) {
/*
* Use a new device's input to add some randomness to
* the system. If this rng device isn't going to be
* used right away, its init function hasn't been
* called yet; so only use the randomness from devices
* that don't need an init callback.
*/
add_early_randomness(rng);
}
out_unlock:
mutex_unlock(&rng_mutex);
out:
return err;
}
EXPORT_SYMBOL_GPL(hwrng_register);
void hwrng_unregister(struct hwrng *rng)
{
int err;
mutex_lock(&rng_mutex);
list_del(&rng->list);
if (current_rng == rng) {
err = enable_best_rng();
if (err) {
drop_current_rng();
cur_rng_set_by_user = 0;
}
}
if (list_empty(&rng_list)) {
mutex_unlock(&rng_mutex);
if (hwrng_fill)
kthread_stop(hwrng_fill);
} else
mutex_unlock(&rng_mutex);
wait_for_completion(&rng->cleanup_done);
}
EXPORT_SYMBOL_GPL(hwrng_unregister);
static void devm_hwrng_release(struct device *dev, void *res)
{
hwrng_unregister(*(struct hwrng **)res);
}
static int devm_hwrng_match(struct device *dev, void *res, void *data)
{
struct hwrng **r = res;
if (WARN_ON(!r || !*r))
return 0;
return *r == data;
}
int devm_hwrng_register(struct device *dev, struct hwrng *rng)
{
struct hwrng **ptr;
int error;
ptr = devres_alloc(devm_hwrng_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return -ENOMEM;
error = hwrng_register(rng);
if (error) {
devres_free(ptr);
return error;
}
*ptr = rng;
devres_add(dev, ptr);
return 0;
}
EXPORT_SYMBOL_GPL(devm_hwrng_register);
void devm_hwrng_unregister(struct device *dev, struct hwrng *rng)
{
devres_release(dev, devm_hwrng_release, devm_hwrng_match, rng);
}
EXPORT_SYMBOL_GPL(devm_hwrng_unregister);
static int __init hwrng_modinit(void)
{
int ret = -ENOMEM;
/* kmalloc makes this safe for virt_to_page() in virtio_rng.c */
rng_buffer = kmalloc(rng_buffer_size(), GFP_KERNEL);
if (!rng_buffer)
return -ENOMEM;
rng_fillbuf = kmalloc(rng_buffer_size(), GFP_KERNEL);
if (!rng_fillbuf) {
kfree(rng_buffer);
return -ENOMEM;
}
ret = register_miscdev();
if (ret) {
kfree(rng_fillbuf);
kfree(rng_buffer);
}
return ret;
}
static void __exit hwrng_modexit(void)
{
mutex_lock(&rng_mutex);
BUG_ON(current_rng);
kfree(rng_buffer);
kfree(rng_fillbuf);
mutex_unlock(&rng_mutex);
unregister_miscdev();
}
module_init(hwrng_modinit);
module_exit(hwrng_modexit);
MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver");
MODULE_LICENSE("GPL");