blob: f77c604239926d464fb2d309675a5e6771ed53a6 [file] [log] [blame]
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -07001/*
Lai Jiangshan47c59802008-10-18 20:28:07 -07002 * device_cgroup.c - device cgroup subsystem
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -07003 *
4 * Copyright 2007 IBM Corp
5 */
6
7#include <linux/device_cgroup.h>
8#include <linux/cgroup.h>
9#include <linux/ctype.h>
10#include <linux/list.h>
11#include <linux/uaccess.h>
Serge E. Hallyn29486df2008-04-29 01:00:14 -070012#include <linux/seq_file.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090013#include <linux/slab.h>
Lai Jiangshan47c59802008-10-18 20:28:07 -070014#include <linux/rcupdate.h>
Li Zefanb4046f02009-04-02 16:57:32 -070015#include <linux/mutex.h>
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070016
17#define ACC_MKNOD 1
18#define ACC_READ 2
19#define ACC_WRITE 4
20#define ACC_MASK (ACC_MKNOD | ACC_READ | ACC_WRITE)
21
22#define DEV_BLOCK 1
23#define DEV_CHAR 2
24#define DEV_ALL 4 /* this represents all devices */
25
Li Zefanb4046f02009-04-02 16:57:32 -070026static DEFINE_MUTEX(devcgroup_mutex);
27
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070028/*
29 * whitelist locking rules:
Li Zefanb4046f02009-04-02 16:57:32 -070030 * hold devcgroup_mutex for update/read.
Lai Jiangshan47c59802008-10-18 20:28:07 -070031 * hold rcu_read_lock() for read.
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070032 */
33
34struct dev_whitelist_item {
35 u32 major, minor;
36 short type;
37 short access;
38 struct list_head list;
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -070039 struct rcu_head rcu;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070040};
41
42struct dev_cgroup {
43 struct cgroup_subsys_state css;
44 struct list_head whitelist;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070045};
46
Pavel Emelyanovb66862f2008-06-05 22:46:24 -070047static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s)
48{
49 return container_of(s, struct dev_cgroup, css);
50}
51
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070052static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup)
53{
Pavel Emelyanovb66862f2008-06-05 22:46:24 -070054 return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id));
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070055}
56
Paul Menagef92523e2008-07-25 01:47:03 -070057static inline struct dev_cgroup *task_devcgroup(struct task_struct *task)
58{
59 return css_to_devcgroup(task_subsys_state(task, devices_subsys_id));
60}
61
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070062struct cgroup_subsys devices_subsys;
63
64static int devcgroup_can_attach(struct cgroup_subsys *ss,
Ben Blumbe367d02009-09-23 15:56:31 -070065 struct cgroup *new_cgroup, struct task_struct *task,
66 bool threadgroup)
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070067{
68 if (current != task && !capable(CAP_SYS_ADMIN))
69 return -EPERM;
70
71 return 0;
72}
73
74/*
Li Zefanb4046f02009-04-02 16:57:32 -070075 * called under devcgroup_mutex
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070076 */
77static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig)
78{
79 struct dev_whitelist_item *wh, *tmp, *new;
80
81 list_for_each_entry(wh, orig, list) {
Li Zefan2cdc7242008-10-18 20:28:06 -070082 new = kmemdup(wh, sizeof(*wh), GFP_KERNEL);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070083 if (!new)
84 goto free_and_exit;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070085 list_add_tail(&new->list, dest);
86 }
87
88 return 0;
89
90free_and_exit:
91 list_for_each_entry_safe(wh, tmp, dest, list) {
92 list_del(&wh->list);
93 kfree(wh);
94 }
95 return -ENOMEM;
96}
97
98/* Stupid prototype - don't bother combining existing entries */
99/*
Li Zefanb4046f02009-04-02 16:57:32 -0700100 * called under devcgroup_mutex
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700101 */
102static int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
103 struct dev_whitelist_item *wh)
104{
Pavel Emelyanovd1ee2972008-06-05 22:46:28 -0700105 struct dev_whitelist_item *whcopy, *walk;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700106
Li Zefan2cdc7242008-10-18 20:28:06 -0700107 whcopy = kmemdup(wh, sizeof(*wh), GFP_KERNEL);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700108 if (!whcopy)
109 return -ENOMEM;
110
Pavel Emelyanovd1ee2972008-06-05 22:46:28 -0700111 list_for_each_entry(walk, &dev_cgroup->whitelist, list) {
112 if (walk->type != wh->type)
113 continue;
114 if (walk->major != wh->major)
115 continue;
116 if (walk->minor != wh->minor)
117 continue;
118
119 walk->access |= wh->access;
120 kfree(whcopy);
121 whcopy = NULL;
122 }
123
124 if (whcopy != NULL)
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700125 list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700126 return 0;
127}
128
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700129static void whitelist_item_free(struct rcu_head *rcu)
130{
131 struct dev_whitelist_item *item;
132
133 item = container_of(rcu, struct dev_whitelist_item, rcu);
134 kfree(item);
135}
136
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700137/*
Li Zefanb4046f02009-04-02 16:57:32 -0700138 * called under devcgroup_mutex
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700139 */
140static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup,
141 struct dev_whitelist_item *wh)
142{
143 struct dev_whitelist_item *walk, *tmp;
144
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700145 list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) {
146 if (walk->type == DEV_ALL)
147 goto remove;
148 if (walk->type != wh->type)
149 continue;
150 if (walk->major != ~0 && walk->major != wh->major)
151 continue;
152 if (walk->minor != ~0 && walk->minor != wh->minor)
153 continue;
154
155remove:
156 walk->access &= ~wh->access;
157 if (!walk->access) {
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700158 list_del_rcu(&walk->list);
159 call_rcu(&walk->rcu, whitelist_item_free);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700160 }
161 }
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700162}
163
164/*
165 * called from kernel/cgroup.c with cgroup_lock() held.
166 */
167static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss,
168 struct cgroup *cgroup)
169{
170 struct dev_cgroup *dev_cgroup, *parent_dev_cgroup;
171 struct cgroup *parent_cgroup;
172 int ret;
173
174 dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL);
175 if (!dev_cgroup)
176 return ERR_PTR(-ENOMEM);
177 INIT_LIST_HEAD(&dev_cgroup->whitelist);
178 parent_cgroup = cgroup->parent;
179
180 if (parent_cgroup == NULL) {
181 struct dev_whitelist_item *wh;
182 wh = kmalloc(sizeof(*wh), GFP_KERNEL);
183 if (!wh) {
184 kfree(dev_cgroup);
185 return ERR_PTR(-ENOMEM);
186 }
187 wh->minor = wh->major = ~0;
188 wh->type = DEV_ALL;
Li Zefan7759fc92008-07-25 01:47:08 -0700189 wh->access = ACC_MASK;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700190 list_add(&wh->list, &dev_cgroup->whitelist);
191 } else {
192 parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup);
Li Zefanb4046f02009-04-02 16:57:32 -0700193 mutex_lock(&devcgroup_mutex);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700194 ret = dev_whitelist_copy(&dev_cgroup->whitelist,
195 &parent_dev_cgroup->whitelist);
Li Zefanb4046f02009-04-02 16:57:32 -0700196 mutex_unlock(&devcgroup_mutex);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700197 if (ret) {
198 kfree(dev_cgroup);
199 return ERR_PTR(ret);
200 }
201 }
202
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700203 return &dev_cgroup->css;
204}
205
206static void devcgroup_destroy(struct cgroup_subsys *ss,
207 struct cgroup *cgroup)
208{
209 struct dev_cgroup *dev_cgroup;
210 struct dev_whitelist_item *wh, *tmp;
211
212 dev_cgroup = cgroup_to_devcgroup(cgroup);
213 list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) {
214 list_del(&wh->list);
215 kfree(wh);
216 }
217 kfree(dev_cgroup);
218}
219
220#define DEVCG_ALLOW 1
221#define DEVCG_DENY 2
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700222#define DEVCG_LIST 3
223
Li Zefan17d213f2008-07-13 12:14:02 -0700224#define MAJMINLEN 13
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700225#define ACCLEN 4
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700226
227static void set_access(char *acc, short access)
228{
229 int idx = 0;
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700230 memset(acc, 0, ACCLEN);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700231 if (access & ACC_READ)
232 acc[idx++] = 'r';
233 if (access & ACC_WRITE)
234 acc[idx++] = 'w';
235 if (access & ACC_MKNOD)
236 acc[idx++] = 'm';
237}
238
239static char type_to_char(short type)
240{
241 if (type == DEV_ALL)
242 return 'a';
243 if (type == DEV_CHAR)
244 return 'c';
245 if (type == DEV_BLOCK)
246 return 'b';
247 return 'X';
248}
249
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700250static void set_majmin(char *str, unsigned m)
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700251{
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700252 if (m == ~0)
Li Zefan7759fc92008-07-25 01:47:08 -0700253 strcpy(str, "*");
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700254 else
Li Zefan7759fc92008-07-25 01:47:08 -0700255 sprintf(str, "%u", m);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700256}
257
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700258static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
259 struct seq_file *m)
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700260{
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700261 struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700262 struct dev_whitelist_item *wh;
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700263 char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN];
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700264
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700265 rcu_read_lock();
266 list_for_each_entry_rcu(wh, &devcgroup->whitelist, list) {
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700267 set_access(acc, wh->access);
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700268 set_majmin(maj, wh->major);
269 set_majmin(min, wh->minor);
270 seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type),
271 maj, min, acc);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700272 }
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700273 rcu_read_unlock();
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700274
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700275 return 0;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700276}
277
278/*
279 * may_access_whitelist:
280 * does the access granted to dev_cgroup c contain the access
281 * requested in whitelist item refwh.
282 * return 1 if yes, 0 if no.
Li Zefanb4046f02009-04-02 16:57:32 -0700283 * call with devcgroup_mutex held
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700284 */
285static int may_access_whitelist(struct dev_cgroup *c,
286 struct dev_whitelist_item *refwh)
287{
288 struct dev_whitelist_item *whitem;
289
290 list_for_each_entry(whitem, &c->whitelist, list) {
291 if (whitem->type & DEV_ALL)
292 return 1;
293 if ((refwh->type & DEV_BLOCK) && !(whitem->type & DEV_BLOCK))
294 continue;
295 if ((refwh->type & DEV_CHAR) && !(whitem->type & DEV_CHAR))
296 continue;
297 if (whitem->major != ~0 && whitem->major != refwh->major)
298 continue;
299 if (whitem->minor != ~0 && whitem->minor != refwh->minor)
300 continue;
Li Zefanec229e82008-07-13 12:14:04 -0700301 if (refwh->access & (~whitem->access))
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700302 continue;
303 return 1;
304 }
305 return 0;
306}
307
308/*
309 * parent_has_perm:
310 * when adding a new allow rule to a device whitelist, the rule
311 * must be allowed in the parent device
312 */
Paul Menagef92523e2008-07-25 01:47:03 -0700313static int parent_has_perm(struct dev_cgroup *childcg,
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700314 struct dev_whitelist_item *wh)
315{
Paul Menagef92523e2008-07-25 01:47:03 -0700316 struct cgroup *pcg = childcg->css.cgroup->parent;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700317 struct dev_cgroup *parent;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700318
319 if (!pcg)
320 return 1;
321 parent = cgroup_to_devcgroup(pcg);
Lai Jiangshan47c59802008-10-18 20:28:07 -0700322 return may_access_whitelist(parent, wh);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700323}
324
325/*
326 * Modify the whitelist using allow/deny rules.
327 * CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD
328 * so we can give a container CAP_MKNOD to let it create devices but not
329 * modify the whitelist.
330 * It seems likely we'll want to add a CAP_CONTAINER capability to allow
331 * us to also grant CAP_SYS_ADMIN to containers without giving away the
332 * device whitelist controls, but for now we'll stick with CAP_SYS_ADMIN
333 *
334 * Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting
335 * new access is only allowed if you're in the top-level cgroup, or your
336 * parent cgroup has the access you're asking for.
337 */
Paul Menagef92523e2008-07-25 01:47:03 -0700338static int devcgroup_update_access(struct dev_cgroup *devcgroup,
339 int filetype, const char *buffer)
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700340{
Paul Menagef92523e2008-07-25 01:47:03 -0700341 const char *b;
Li Zefan7759fc92008-07-25 01:47:08 -0700342 char *endp;
Li Zefanc012a542008-10-18 20:28:07 -0700343 int count;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700344 struct dev_whitelist_item wh;
345
346 if (!capable(CAP_SYS_ADMIN))
347 return -EPERM;
348
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700349 memset(&wh, 0, sizeof(wh));
350 b = buffer;
351
352 switch (*b) {
353 case 'a':
354 wh.type = DEV_ALL;
355 wh.access = ACC_MASK;
Li Zefand823f6b2008-07-04 10:00:07 -0700356 wh.major = ~0;
357 wh.minor = ~0;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700358 goto handle;
359 case 'b':
360 wh.type = DEV_BLOCK;
361 break;
362 case 'c':
363 wh.type = DEV_CHAR;
364 break;
365 default:
Paul Menagef92523e2008-07-25 01:47:03 -0700366 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700367 }
368 b++;
Paul Menagef92523e2008-07-25 01:47:03 -0700369 if (!isspace(*b))
370 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700371 b++;
372 if (*b == '*') {
373 wh.major = ~0;
374 b++;
375 } else if (isdigit(*b)) {
Li Zefan7759fc92008-07-25 01:47:08 -0700376 wh.major = simple_strtoul(b, &endp, 10);
377 b = endp;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700378 } else {
Paul Menagef92523e2008-07-25 01:47:03 -0700379 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700380 }
Paul Menagef92523e2008-07-25 01:47:03 -0700381 if (*b != ':')
382 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700383 b++;
384
385 /* read minor */
386 if (*b == '*') {
387 wh.minor = ~0;
388 b++;
389 } else if (isdigit(*b)) {
Li Zefan7759fc92008-07-25 01:47:08 -0700390 wh.minor = simple_strtoul(b, &endp, 10);
391 b = endp;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700392 } else {
Paul Menagef92523e2008-07-25 01:47:03 -0700393 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700394 }
Paul Menagef92523e2008-07-25 01:47:03 -0700395 if (!isspace(*b))
396 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700397 for (b++, count = 0; count < 3; count++, b++) {
398 switch (*b) {
399 case 'r':
400 wh.access |= ACC_READ;
401 break;
402 case 'w':
403 wh.access |= ACC_WRITE;
404 break;
405 case 'm':
406 wh.access |= ACC_MKNOD;
407 break;
408 case '\n':
409 case '\0':
410 count = 3;
411 break;
412 default:
Paul Menagef92523e2008-07-25 01:47:03 -0700413 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700414 }
415 }
416
417handle:
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700418 switch (filetype) {
419 case DEVCG_ALLOW:
Paul Menagef92523e2008-07-25 01:47:03 -0700420 if (!parent_has_perm(devcgroup, &wh))
421 return -EPERM;
422 return dev_whitelist_add(devcgroup, &wh);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700423 case DEVCG_DENY:
424 dev_whitelist_rm(devcgroup, &wh);
425 break;
426 default:
Paul Menagef92523e2008-07-25 01:47:03 -0700427 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700428 }
Paul Menagef92523e2008-07-25 01:47:03 -0700429 return 0;
430}
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700431
Paul Menagef92523e2008-07-25 01:47:03 -0700432static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft,
433 const char *buffer)
434{
435 int retval;
Li Zefanb4046f02009-04-02 16:57:32 -0700436
437 mutex_lock(&devcgroup_mutex);
Paul Menagef92523e2008-07-25 01:47:03 -0700438 retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp),
439 cft->private, buffer);
Li Zefanb4046f02009-04-02 16:57:32 -0700440 mutex_unlock(&devcgroup_mutex);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700441 return retval;
442}
443
444static struct cftype dev_cgroup_files[] = {
445 {
446 .name = "allow",
Paul Menagef92523e2008-07-25 01:47:03 -0700447 .write_string = devcgroup_access_write,
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700448 .private = DEVCG_ALLOW,
449 },
450 {
451 .name = "deny",
Paul Menagef92523e2008-07-25 01:47:03 -0700452 .write_string = devcgroup_access_write,
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700453 .private = DEVCG_DENY,
454 },
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700455 {
456 .name = "list",
457 .read_seq_string = devcgroup_seq_read,
458 .private = DEVCG_LIST,
459 },
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700460};
461
462static int devcgroup_populate(struct cgroup_subsys *ss,
463 struct cgroup *cgroup)
464{
465 return cgroup_add_files(cgroup, ss, dev_cgroup_files,
466 ARRAY_SIZE(dev_cgroup_files));
467}
468
469struct cgroup_subsys devices_subsys = {
470 .name = "devices",
471 .can_attach = devcgroup_can_attach,
472 .create = devcgroup_create,
473 .destroy = devcgroup_destroy,
474 .populate = devcgroup_populate,
475 .subsys_id = devices_subsys_id,
476};
477
478int devcgroup_inode_permission(struct inode *inode, int mask)
479{
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700480 struct dev_cgroup *dev_cgroup;
481 struct dev_whitelist_item *wh;
482
483 dev_t device = inode->i_rdev;
484 if (!device)
485 return 0;
486 if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode))
487 return 0;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700488
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700489 rcu_read_lock();
Li Zefan36fd71d2008-09-02 14:35:52 -0700490
491 dev_cgroup = task_devcgroup(current);
492
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700493 list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700494 if (wh->type & DEV_ALL)
Li Zefancd500812009-06-17 16:26:33 -0700495 goto found;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700496 if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
497 continue;
498 if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode))
499 continue;
500 if (wh->major != ~0 && wh->major != imajor(inode))
501 continue;
502 if (wh->minor != ~0 && wh->minor != iminor(inode))
503 continue;
Li Zefancd500812009-06-17 16:26:33 -0700504
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700505 if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE))
506 continue;
507 if ((mask & MAY_READ) && !(wh->access & ACC_READ))
508 continue;
Li Zefancd500812009-06-17 16:26:33 -0700509found:
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700510 rcu_read_unlock();
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700511 return 0;
512 }
Li Zefan36fd71d2008-09-02 14:35:52 -0700513
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700514 rcu_read_unlock();
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700515
516 return -EPERM;
517}
518
519int devcgroup_inode_mknod(int mode, dev_t dev)
520{
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700521 struct dev_cgroup *dev_cgroup;
522 struct dev_whitelist_item *wh;
523
Serge E. Hallyn0b82ac32009-01-07 18:07:46 -0800524 if (!S_ISBLK(mode) && !S_ISCHR(mode))
525 return 0;
526
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700527 rcu_read_lock();
Li Zefan36fd71d2008-09-02 14:35:52 -0700528
529 dev_cgroup = task_devcgroup(current);
530
Lai Jiangshan116e0572009-01-07 18:07:45 -0800531 list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700532 if (wh->type & DEV_ALL)
Li Zefancd500812009-06-17 16:26:33 -0700533 goto found;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700534 if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))
535 continue;
536 if ((wh->type & DEV_CHAR) && !S_ISCHR(mode))
537 continue;
538 if (wh->major != ~0 && wh->major != MAJOR(dev))
539 continue;
540 if (wh->minor != ~0 && wh->minor != MINOR(dev))
541 continue;
Li Zefancd500812009-06-17 16:26:33 -0700542
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700543 if (!(wh->access & ACC_MKNOD))
544 continue;
Li Zefancd500812009-06-17 16:26:33 -0700545found:
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700546 rcu_read_unlock();
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700547 return 0;
548 }
Li Zefan36fd71d2008-09-02 14:35:52 -0700549
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700550 rcu_read_unlock();
Li Zefan36fd71d2008-09-02 14:35:52 -0700551
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700552 return -EPERM;
553}