hwrng: remember rng chosen by user
When a user chooses a rng source via sysfs attribute this rng should be sticky, even when other sources with better quality to register. This patch introduces a simple way to remember the user's choice. This is reflected by a new sysfs attribute file 'rng_selected' which shows if the current rng has been chosen by userspace. The new attribute file shows '1' for user selected rng and '0' otherwise. Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com> Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
parent
2bbb698388
commit
10a515ddb5
@ -28,6 +28,8 @@
|
|||||||
#define RNG_MODULE_NAME "hw_random"
|
#define RNG_MODULE_NAME "hw_random"
|
||||||
|
|
||||||
static struct hwrng *current_rng;
|
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;
|
static struct task_struct *hwrng_fill;
|
||||||
/* list of registered rngs, sorted decending by quality */
|
/* list of registered rngs, sorted decending by quality */
|
||||||
static LIST_HEAD(rng_list);
|
static LIST_HEAD(rng_list);
|
||||||
@ -304,6 +306,7 @@ static ssize_t hwrng_attr_current_store(struct device *dev,
|
|||||||
list_for_each_entry(rng, &rng_list, list) {
|
list_for_each_entry(rng, &rng_list, list) {
|
||||||
if (sysfs_streq(rng->name, buf)) {
|
if (sysfs_streq(rng->name, buf)) {
|
||||||
err = 0;
|
err = 0;
|
||||||
|
cur_rng_set_by_user = 1;
|
||||||
if (rng != current_rng)
|
if (rng != current_rng)
|
||||||
err = set_current_rng(rng);
|
err = set_current_rng(rng);
|
||||||
break;
|
break;
|
||||||
@ -352,16 +355,27 @@ static ssize_t hwrng_attr_available_show(struct device *dev,
|
|||||||
return strlen(buf);
|
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,
|
static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR,
|
||||||
hwrng_attr_current_show,
|
hwrng_attr_current_show,
|
||||||
hwrng_attr_current_store);
|
hwrng_attr_current_store);
|
||||||
static DEVICE_ATTR(rng_available, S_IRUGO,
|
static DEVICE_ATTR(rng_available, S_IRUGO,
|
||||||
hwrng_attr_available_show,
|
hwrng_attr_available_show,
|
||||||
NULL);
|
NULL);
|
||||||
|
static DEVICE_ATTR(rng_selected, S_IRUGO,
|
||||||
|
hwrng_attr_selected_show,
|
||||||
|
NULL);
|
||||||
|
|
||||||
static struct attribute *rng_dev_attrs[] = {
|
static struct attribute *rng_dev_attrs[] = {
|
||||||
&dev_attr_rng_current.attr,
|
&dev_attr_rng_current.attr,
|
||||||
&dev_attr_rng_available.attr,
|
&dev_attr_rng_available.attr,
|
||||||
|
&dev_attr_rng_selected.attr,
|
||||||
NULL
|
NULL
|
||||||
};
|
};
|
||||||
|
|
||||||
@ -444,10 +458,12 @@ int hwrng_register(struct hwrng *rng)
|
|||||||
|
|
||||||
old_rng = current_rng;
|
old_rng = current_rng;
|
||||||
err = 0;
|
err = 0;
|
||||||
if (!old_rng || (rng->quality > old_rng->quality)) {
|
if (!old_rng ||
|
||||||
|
(!cur_rng_set_by_user && rng->quality > old_rng->quality)) {
|
||||||
/*
|
/*
|
||||||
* Set new rng as current as the new rng source
|
* Set new rng as current as the new rng source
|
||||||
* provides better entropy quality.
|
* provides better entropy quality and was not
|
||||||
|
* chosen by userspace.
|
||||||
*/
|
*/
|
||||||
err = set_current_rng(rng);
|
err = set_current_rng(rng);
|
||||||
if (err)
|
if (err)
|
||||||
@ -479,6 +495,7 @@ void hwrng_unregister(struct hwrng *rng)
|
|||||||
list_del(&rng->list);
|
list_del(&rng->list);
|
||||||
if (current_rng == rng) {
|
if (current_rng == rng) {
|
||||||
drop_current_rng();
|
drop_current_rng();
|
||||||
|
cur_rng_set_by_user = 0;
|
||||||
/* rng_list is sorted by quality, use the best (=first) one */
|
/* rng_list is sorted by quality, use the best (=first) one */
|
||||||
if (!list_empty(&rng_list)) {
|
if (!list_empty(&rng_list)) {
|
||||||
struct hwrng *new_rng;
|
struct hwrng *new_rng;
|
||||||
|
Loading…
Reference in New Issue
Block a user