2008-04-29 02:00:10 -06:00
|
|
|
/*
|
|
|
|
* dev_cgroup.c - device cgroup subsystem
|
|
|
|
*
|
|
|
|
* Copyright 2007 IBM Corp
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/device_cgroup.h>
|
|
|
|
#include <linux/cgroup.h>
|
|
|
|
#include <linux/ctype.h>
|
|
|
|
#include <linux/list.h>
|
|
|
|
#include <linux/uaccess.h>
|
2008-04-29 02:00:14 -06:00
|
|
|
#include <linux/seq_file.h>
|
2008-04-29 02:00:10 -06:00
|
|
|
|
|
|
|
#define ACC_MKNOD 1
|
|
|
|
#define ACC_READ 2
|
|
|
|
#define ACC_WRITE 4
|
|
|
|
#define ACC_MASK (ACC_MKNOD | ACC_READ | ACC_WRITE)
|
|
|
|
|
|
|
|
#define DEV_BLOCK 1
|
|
|
|
#define DEV_CHAR 2
|
|
|
|
#define DEV_ALL 4 /* this represents all devices */
|
|
|
|
|
|
|
|
/*
|
|
|
|
* whitelist locking rules:
|
|
|
|
* cgroup_lock() cannot be taken under dev_cgroup->lock.
|
|
|
|
* dev_cgroup->lock can be taken with or without cgroup_lock().
|
|
|
|
*
|
|
|
|
* modifications always require cgroup_lock
|
|
|
|
* modifications to a list which is visible require the
|
|
|
|
* dev_cgroup->lock *and* cgroup_lock()
|
|
|
|
* walking the list requires dev_cgroup->lock or cgroup_lock().
|
|
|
|
*
|
|
|
|
* reasoning: dev_whitelist_copy() needs to kmalloc, so needs
|
|
|
|
* a mutex, which the cgroup_lock() is. Since modifying
|
|
|
|
* a visible list requires both locks, either lock can be
|
|
|
|
* taken for walking the list.
|
|
|
|
*/
|
|
|
|
|
|
|
|
struct dev_whitelist_item {
|
|
|
|
u32 major, minor;
|
|
|
|
short type;
|
|
|
|
short access;
|
|
|
|
struct list_head list;
|
|
|
|
};
|
|
|
|
|
|
|
|
struct dev_cgroup {
|
|
|
|
struct cgroup_subsys_state css;
|
|
|
|
struct list_head whitelist;
|
|
|
|
spinlock_t lock;
|
|
|
|
};
|
|
|
|
|
2008-06-05 23:46:24 -06:00
|
|
|
static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s)
|
|
|
|
{
|
|
|
|
return container_of(s, struct dev_cgroup, css);
|
|
|
|
}
|
|
|
|
|
2008-04-29 02:00:10 -06:00
|
|
|
static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup)
|
|
|
|
{
|
2008-06-05 23:46:24 -06:00
|
|
|
return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id));
|
2008-04-29 02:00:10 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
struct cgroup_subsys devices_subsys;
|
|
|
|
|
|
|
|
static int devcgroup_can_attach(struct cgroup_subsys *ss,
|
|
|
|
struct cgroup *new_cgroup, struct task_struct *task)
|
|
|
|
{
|
|
|
|
if (current != task && !capable(CAP_SYS_ADMIN))
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* called under cgroup_lock()
|
|
|
|
*/
|
|
|
|
static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig)
|
|
|
|
{
|
|
|
|
struct dev_whitelist_item *wh, *tmp, *new;
|
|
|
|
|
|
|
|
list_for_each_entry(wh, orig, list) {
|
|
|
|
new = kmalloc(sizeof(*wh), GFP_KERNEL);
|
|
|
|
if (!new)
|
|
|
|
goto free_and_exit;
|
|
|
|
new->major = wh->major;
|
|
|
|
new->minor = wh->minor;
|
|
|
|
new->type = wh->type;
|
|
|
|
new->access = wh->access;
|
|
|
|
list_add_tail(&new->list, dest);
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
free_and_exit:
|
|
|
|
list_for_each_entry_safe(wh, tmp, dest, list) {
|
|
|
|
list_del(&wh->list);
|
|
|
|
kfree(wh);
|
|
|
|
}
|
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Stupid prototype - don't bother combining existing entries */
|
|
|
|
/*
|
|
|
|
* called under cgroup_lock()
|
|
|
|
* since the list is visible to other tasks, we need the spinlock also
|
|
|
|
*/
|
|
|
|
static int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
|
|
|
|
struct dev_whitelist_item *wh)
|
|
|
|
{
|
2008-06-05 23:46:28 -06:00
|
|
|
struct dev_whitelist_item *whcopy, *walk;
|
2008-04-29 02:00:10 -06:00
|
|
|
|
|
|
|
whcopy = kmalloc(sizeof(*whcopy), GFP_KERNEL);
|
|
|
|
if (!whcopy)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
memcpy(whcopy, wh, sizeof(*whcopy));
|
|
|
|
spin_lock(&dev_cgroup->lock);
|
2008-06-05 23:46:28 -06:00
|
|
|
list_for_each_entry(walk, &dev_cgroup->whitelist, list) {
|
|
|
|
if (walk->type != wh->type)
|
|
|
|
continue;
|
|
|
|
if (walk->major != wh->major)
|
|
|
|
continue;
|
|
|
|
if (walk->minor != wh->minor)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
walk->access |= wh->access;
|
|
|
|
kfree(whcopy);
|
|
|
|
whcopy = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (whcopy != NULL)
|
|
|
|
list_add_tail(&whcopy->list, &dev_cgroup->whitelist);
|
2008-04-29 02:00:10 -06:00
|
|
|
spin_unlock(&dev_cgroup->lock);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* called under cgroup_lock()
|
|
|
|
* since the list is visible to other tasks, we need the spinlock also
|
|
|
|
*/
|
|
|
|
static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup,
|
|
|
|
struct dev_whitelist_item *wh)
|
|
|
|
{
|
|
|
|
struct dev_whitelist_item *walk, *tmp;
|
|
|
|
|
|
|
|
spin_lock(&dev_cgroup->lock);
|
|
|
|
list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) {
|
|
|
|
if (walk->type == DEV_ALL)
|
|
|
|
goto remove;
|
|
|
|
if (walk->type != wh->type)
|
|
|
|
continue;
|
|
|
|
if (walk->major != ~0 && walk->major != wh->major)
|
|
|
|
continue;
|
|
|
|
if (walk->minor != ~0 && walk->minor != wh->minor)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
remove:
|
|
|
|
walk->access &= ~wh->access;
|
|
|
|
if (!walk->access) {
|
|
|
|
list_del(&walk->list);
|
|
|
|
kfree(walk);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
spin_unlock(&dev_cgroup->lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* called from kernel/cgroup.c with cgroup_lock() held.
|
|
|
|
*/
|
|
|
|
static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss,
|
|
|
|
struct cgroup *cgroup)
|
|
|
|
{
|
|
|
|
struct dev_cgroup *dev_cgroup, *parent_dev_cgroup;
|
|
|
|
struct cgroup *parent_cgroup;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL);
|
|
|
|
if (!dev_cgroup)
|
|
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
INIT_LIST_HEAD(&dev_cgroup->whitelist);
|
|
|
|
parent_cgroup = cgroup->parent;
|
|
|
|
|
|
|
|
if (parent_cgroup == NULL) {
|
|
|
|
struct dev_whitelist_item *wh;
|
|
|
|
wh = kmalloc(sizeof(*wh), GFP_KERNEL);
|
|
|
|
if (!wh) {
|
|
|
|
kfree(dev_cgroup);
|
|
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
}
|
|
|
|
wh->minor = wh->major = ~0;
|
|
|
|
wh->type = DEV_ALL;
|
|
|
|
wh->access = ACC_MKNOD | ACC_READ | ACC_WRITE;
|
|
|
|
list_add(&wh->list, &dev_cgroup->whitelist);
|
|
|
|
} else {
|
|
|
|
parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup);
|
|
|
|
ret = dev_whitelist_copy(&dev_cgroup->whitelist,
|
|
|
|
&parent_dev_cgroup->whitelist);
|
|
|
|
if (ret) {
|
|
|
|
kfree(dev_cgroup);
|
|
|
|
return ERR_PTR(ret);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
spin_lock_init(&dev_cgroup->lock);
|
|
|
|
return &dev_cgroup->css;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void devcgroup_destroy(struct cgroup_subsys *ss,
|
|
|
|
struct cgroup *cgroup)
|
|
|
|
{
|
|
|
|
struct dev_cgroup *dev_cgroup;
|
|
|
|
struct dev_whitelist_item *wh, *tmp;
|
|
|
|
|
|
|
|
dev_cgroup = cgroup_to_devcgroup(cgroup);
|
|
|
|
list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) {
|
|
|
|
list_del(&wh->list);
|
|
|
|
kfree(wh);
|
|
|
|
}
|
|
|
|
kfree(dev_cgroup);
|
|
|
|
}
|
|
|
|
|
|
|
|
#define DEVCG_ALLOW 1
|
|
|
|
#define DEVCG_DENY 2
|
2008-04-29 02:00:14 -06:00
|
|
|
#define DEVCG_LIST 3
|
|
|
|
|
|
|
|
#define MAJMINLEN 10
|
|
|
|
#define ACCLEN 4
|
2008-04-29 02:00:10 -06:00
|
|
|
|
|
|
|
static void set_access(char *acc, short access)
|
|
|
|
{
|
|
|
|
int idx = 0;
|
2008-04-29 02:00:14 -06:00
|
|
|
memset(acc, 0, ACCLEN);
|
2008-04-29 02:00:10 -06:00
|
|
|
if (access & ACC_READ)
|
|
|
|
acc[idx++] = 'r';
|
|
|
|
if (access & ACC_WRITE)
|
|
|
|
acc[idx++] = 'w';
|
|
|
|
if (access & ACC_MKNOD)
|
|
|
|
acc[idx++] = 'm';
|
|
|
|
}
|
|
|
|
|
|
|
|
static char type_to_char(short type)
|
|
|
|
{
|
|
|
|
if (type == DEV_ALL)
|
|
|
|
return 'a';
|
|
|
|
if (type == DEV_CHAR)
|
|
|
|
return 'c';
|
|
|
|
if (type == DEV_BLOCK)
|
|
|
|
return 'b';
|
|
|
|
return 'X';
|
|
|
|
}
|
|
|
|
|
2008-04-29 02:00:14 -06:00
|
|
|
static void set_majmin(char *str, unsigned m)
|
2008-04-29 02:00:10 -06:00
|
|
|
{
|
2008-04-29 02:00:14 -06:00
|
|
|
memset(str, 0, MAJMINLEN);
|
2008-04-29 02:00:10 -06:00
|
|
|
if (m == ~0)
|
|
|
|
sprintf(str, "*");
|
|
|
|
else
|
2008-04-29 02:00:14 -06:00
|
|
|
snprintf(str, MAJMINLEN, "%d", m);
|
2008-04-29 02:00:10 -06:00
|
|
|
}
|
|
|
|
|
2008-04-29 02:00:14 -06:00
|
|
|
static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
|
|
|
|
struct seq_file *m)
|
2008-04-29 02:00:10 -06:00
|
|
|
{
|
2008-04-29 02:00:14 -06:00
|
|
|
struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup);
|
2008-04-29 02:00:10 -06:00
|
|
|
struct dev_whitelist_item *wh;
|
2008-04-29 02:00:14 -06:00
|
|
|
char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN];
|
2008-04-29 02:00:10 -06:00
|
|
|
|
|
|
|
spin_lock(&devcgroup->lock);
|
|
|
|
list_for_each_entry(wh, &devcgroup->whitelist, list) {
|
|
|
|
set_access(acc, wh->access);
|
2008-04-29 02:00:14 -06:00
|
|
|
set_majmin(maj, wh->major);
|
|
|
|
set_majmin(min, wh->minor);
|
|
|
|
seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type),
|
|
|
|
maj, min, acc);
|
2008-04-29 02:00:10 -06:00
|
|
|
}
|
|
|
|
spin_unlock(&devcgroup->lock);
|
|
|
|
|
2008-04-29 02:00:14 -06:00
|
|
|
return 0;
|
2008-04-29 02:00:10 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* may_access_whitelist:
|
|
|
|
* does the access granted to dev_cgroup c contain the access
|
|
|
|
* requested in whitelist item refwh.
|
|
|
|
* return 1 if yes, 0 if no.
|
|
|
|
* call with c->lock held
|
|
|
|
*/
|
|
|
|
static int may_access_whitelist(struct dev_cgroup *c,
|
|
|
|
struct dev_whitelist_item *refwh)
|
|
|
|
{
|
|
|
|
struct dev_whitelist_item *whitem;
|
|
|
|
|
|
|
|
list_for_each_entry(whitem, &c->whitelist, list) {
|
|
|
|
if (whitem->type & DEV_ALL)
|
|
|
|
return 1;
|
|
|
|
if ((refwh->type & DEV_BLOCK) && !(whitem->type & DEV_BLOCK))
|
|
|
|
continue;
|
|
|
|
if ((refwh->type & DEV_CHAR) && !(whitem->type & DEV_CHAR))
|
|
|
|
continue;
|
|
|
|
if (whitem->major != ~0 && whitem->major != refwh->major)
|
|
|
|
continue;
|
|
|
|
if (whitem->minor != ~0 && whitem->minor != refwh->minor)
|
|
|
|
continue;
|
|
|
|
if (refwh->access & (~(whitem->access | ACC_MASK)))
|
|
|
|
continue;
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* parent_has_perm:
|
|
|
|
* when adding a new allow rule to a device whitelist, the rule
|
|
|
|
* must be allowed in the parent device
|
|
|
|
*/
|
|
|
|
static int parent_has_perm(struct cgroup *childcg,
|
|
|
|
struct dev_whitelist_item *wh)
|
|
|
|
{
|
|
|
|
struct cgroup *pcg = childcg->parent;
|
|
|
|
struct dev_cgroup *parent;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!pcg)
|
|
|
|
return 1;
|
|
|
|
parent = cgroup_to_devcgroup(pcg);
|
|
|
|
spin_lock(&parent->lock);
|
|
|
|
ret = may_access_whitelist(parent, wh);
|
|
|
|
spin_unlock(&parent->lock);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Modify the whitelist using allow/deny rules.
|
|
|
|
* CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD
|
|
|
|
* so we can give a container CAP_MKNOD to let it create devices but not
|
|
|
|
* modify the whitelist.
|
|
|
|
* It seems likely we'll want to add a CAP_CONTAINER capability to allow
|
|
|
|
* us to also grant CAP_SYS_ADMIN to containers without giving away the
|
|
|
|
* device whitelist controls, but for now we'll stick with CAP_SYS_ADMIN
|
|
|
|
*
|
|
|
|
* Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting
|
|
|
|
* new access is only allowed if you're in the top-level cgroup, or your
|
|
|
|
* parent cgroup has the access you're asking for.
|
|
|
|
*/
|
|
|
|
static ssize_t devcgroup_access_write(struct cgroup *cgroup, struct cftype *cft,
|
|
|
|
struct file *file, const char __user *userbuf,
|
|
|
|
size_t nbytes, loff_t *ppos)
|
|
|
|
{
|
|
|
|
struct cgroup *cur_cgroup;
|
|
|
|
struct dev_cgroup *devcgroup, *cur_devcgroup;
|
|
|
|
int filetype = cft->private;
|
|
|
|
char *buffer, *b;
|
|
|
|
int retval = 0, count;
|
|
|
|
struct dev_whitelist_item wh;
|
|
|
|
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
|
|
return -EPERM;
|
|
|
|
|
|
|
|
devcgroup = cgroup_to_devcgroup(cgroup);
|
|
|
|
cur_cgroup = task_cgroup(current, devices_subsys.subsys_id);
|
|
|
|
cur_devcgroup = cgroup_to_devcgroup(cur_cgroup);
|
|
|
|
|
|
|
|
buffer = kmalloc(nbytes+1, GFP_KERNEL);
|
|
|
|
if (!buffer)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
if (copy_from_user(buffer, userbuf, nbytes)) {
|
|
|
|
retval = -EFAULT;
|
|
|
|
goto out1;
|
|
|
|
}
|
|
|
|
buffer[nbytes] = 0; /* nul-terminate */
|
|
|
|
|
|
|
|
cgroup_lock();
|
|
|
|
if (cgroup_is_removed(cgroup)) {
|
|
|
|
retval = -ENODEV;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
|
|
|
|
memset(&wh, 0, sizeof(wh));
|
|
|
|
b = buffer;
|
|
|
|
|
|
|
|
switch (*b) {
|
|
|
|
case 'a':
|
|
|
|
wh.type = DEV_ALL;
|
|
|
|
wh.access = ACC_MASK;
|
2008-07-04 11:00:07 -06:00
|
|
|
wh.major = ~0;
|
|
|
|
wh.minor = ~0;
|
2008-04-29 02:00:10 -06:00
|
|
|
goto handle;
|
|
|
|
case 'b':
|
|
|
|
wh.type = DEV_BLOCK;
|
|
|
|
break;
|
|
|
|
case 'c':
|
|
|
|
wh.type = DEV_CHAR;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
retval = -EINVAL;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
b++;
|
|
|
|
if (!isspace(*b)) {
|
|
|
|
retval = -EINVAL;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
b++;
|
|
|
|
if (*b == '*') {
|
|
|
|
wh.major = ~0;
|
|
|
|
b++;
|
|
|
|
} else if (isdigit(*b)) {
|
|
|
|
wh.major = 0;
|
|
|
|
while (isdigit(*b)) {
|
|
|
|
wh.major = wh.major*10+(*b-'0');
|
|
|
|
b++;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
retval = -EINVAL;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
if (*b != ':') {
|
|
|
|
retval = -EINVAL;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
b++;
|
|
|
|
|
|
|
|
/* read minor */
|
|
|
|
if (*b == '*') {
|
|
|
|
wh.minor = ~0;
|
|
|
|
b++;
|
|
|
|
} else if (isdigit(*b)) {
|
|
|
|
wh.minor = 0;
|
|
|
|
while (isdigit(*b)) {
|
|
|
|
wh.minor = wh.minor*10+(*b-'0');
|
|
|
|
b++;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
retval = -EINVAL;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
if (!isspace(*b)) {
|
|
|
|
retval = -EINVAL;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
for (b++, count = 0; count < 3; count++, b++) {
|
|
|
|
switch (*b) {
|
|
|
|
case 'r':
|
|
|
|
wh.access |= ACC_READ;
|
|
|
|
break;
|
|
|
|
case 'w':
|
|
|
|
wh.access |= ACC_WRITE;
|
|
|
|
break;
|
|
|
|
case 'm':
|
|
|
|
wh.access |= ACC_MKNOD;
|
|
|
|
break;
|
|
|
|
case '\n':
|
|
|
|
case '\0':
|
|
|
|
count = 3;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
retval = -EINVAL;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
handle:
|
|
|
|
retval = 0;
|
|
|
|
switch (filetype) {
|
|
|
|
case DEVCG_ALLOW:
|
|
|
|
if (!parent_has_perm(cgroup, &wh))
|
|
|
|
retval = -EPERM;
|
|
|
|
else
|
|
|
|
retval = dev_whitelist_add(devcgroup, &wh);
|
|
|
|
break;
|
|
|
|
case DEVCG_DENY:
|
|
|
|
dev_whitelist_rm(devcgroup, &wh);
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
retval = -EINVAL;
|
|
|
|
goto out2;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (retval == 0)
|
|
|
|
retval = nbytes;
|
|
|
|
|
|
|
|
out2:
|
|
|
|
cgroup_unlock();
|
|
|
|
out1:
|
|
|
|
kfree(buffer);
|
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct cftype dev_cgroup_files[] = {
|
|
|
|
{
|
|
|
|
.name = "allow",
|
|
|
|
.write = devcgroup_access_write,
|
|
|
|
.private = DEVCG_ALLOW,
|
|
|
|
},
|
|
|
|
{
|
|
|
|
.name = "deny",
|
|
|
|
.write = devcgroup_access_write,
|
|
|
|
.private = DEVCG_DENY,
|
|
|
|
},
|
2008-04-29 02:00:14 -06:00
|
|
|
{
|
|
|
|
.name = "list",
|
|
|
|
.read_seq_string = devcgroup_seq_read,
|
|
|
|
.private = DEVCG_LIST,
|
|
|
|
},
|
2008-04-29 02:00:10 -06:00
|
|
|
};
|
|
|
|
|
|
|
|
static int devcgroup_populate(struct cgroup_subsys *ss,
|
|
|
|
struct cgroup *cgroup)
|
|
|
|
{
|
|
|
|
return cgroup_add_files(cgroup, ss, dev_cgroup_files,
|
|
|
|
ARRAY_SIZE(dev_cgroup_files));
|
|
|
|
}
|
|
|
|
|
|
|
|
struct cgroup_subsys devices_subsys = {
|
|
|
|
.name = "devices",
|
|
|
|
.can_attach = devcgroup_can_attach,
|
|
|
|
.create = devcgroup_create,
|
|
|
|
.destroy = devcgroup_destroy,
|
|
|
|
.populate = devcgroup_populate,
|
|
|
|
.subsys_id = devices_subsys_id,
|
|
|
|
};
|
|
|
|
|
|
|
|
int devcgroup_inode_permission(struct inode *inode, int mask)
|
|
|
|
{
|
|
|
|
struct dev_cgroup *dev_cgroup;
|
|
|
|
struct dev_whitelist_item *wh;
|
|
|
|
|
|
|
|
dev_t device = inode->i_rdev;
|
|
|
|
if (!device)
|
|
|
|
return 0;
|
|
|
|
if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode))
|
|
|
|
return 0;
|
2008-06-05 23:46:26 -06:00
|
|
|
dev_cgroup = css_to_devcgroup(task_subsys_state(current,
|
|
|
|
devices_subsys_id));
|
2008-04-29 02:00:10 -06:00
|
|
|
if (!dev_cgroup)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
spin_lock(&dev_cgroup->lock);
|
|
|
|
list_for_each_entry(wh, &dev_cgroup->whitelist, list) {
|
|
|
|
if (wh->type & DEV_ALL)
|
|
|
|
goto acc_check;
|
|
|
|
if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
|
|
|
|
continue;
|
|
|
|
if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode))
|
|
|
|
continue;
|
|
|
|
if (wh->major != ~0 && wh->major != imajor(inode))
|
|
|
|
continue;
|
|
|
|
if (wh->minor != ~0 && wh->minor != iminor(inode))
|
|
|
|
continue;
|
|
|
|
acc_check:
|
|
|
|
if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE))
|
|
|
|
continue;
|
|
|
|
if ((mask & MAY_READ) && !(wh->access & ACC_READ))
|
|
|
|
continue;
|
|
|
|
spin_unlock(&dev_cgroup->lock);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
spin_unlock(&dev_cgroup->lock);
|
|
|
|
|
|
|
|
return -EPERM;
|
|
|
|
}
|
|
|
|
|
|
|
|
int devcgroup_inode_mknod(int mode, dev_t dev)
|
|
|
|
{
|
|
|
|
struct dev_cgroup *dev_cgroup;
|
|
|
|
struct dev_whitelist_item *wh;
|
|
|
|
|
2008-06-05 23:46:26 -06:00
|
|
|
dev_cgroup = css_to_devcgroup(task_subsys_state(current,
|
|
|
|
devices_subsys_id));
|
2008-04-29 02:00:10 -06:00
|
|
|
if (!dev_cgroup)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
spin_lock(&dev_cgroup->lock);
|
|
|
|
list_for_each_entry(wh, &dev_cgroup->whitelist, list) {
|
|
|
|
if (wh->type & DEV_ALL)
|
|
|
|
goto acc_check;
|
|
|
|
if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))
|
|
|
|
continue;
|
|
|
|
if ((wh->type & DEV_CHAR) && !S_ISCHR(mode))
|
|
|
|
continue;
|
|
|
|
if (wh->major != ~0 && wh->major != MAJOR(dev))
|
|
|
|
continue;
|
|
|
|
if (wh->minor != ~0 && wh->minor != MINOR(dev))
|
|
|
|
continue;
|
|
|
|
acc_check:
|
|
|
|
if (!(wh->access & ACC_MKNOD))
|
|
|
|
continue;
|
|
|
|
spin_unlock(&dev_cgroup->lock);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
spin_unlock(&dev_cgroup->lock);
|
|
|
|
return -EPERM;
|
|
|
|
}
|