blob: b8186bac8b7eb08088b40914137e4f51b8e403fd [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>
Lai Jiangshan47c59802008-10-18 20:28:07 -070013#include <linux/rcupdate.h>
Li Zefanb4046f02009-04-02 16:57:32 -070014#include <linux/mutex.h>
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070015
16#define ACC_MKNOD 1
17#define ACC_READ 2
18#define ACC_WRITE 4
19#define ACC_MASK (ACC_MKNOD | ACC_READ | ACC_WRITE)
20
21#define DEV_BLOCK 1
22#define DEV_CHAR 2
23#define DEV_ALL 4 /* this represents all devices */
24
Li Zefanb4046f02009-04-02 16:57:32 -070025static DEFINE_MUTEX(devcgroup_mutex);
26
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070027/*
28 * whitelist locking rules:
Li Zefanb4046f02009-04-02 16:57:32 -070029 * hold devcgroup_mutex for update/read.
Lai Jiangshan47c59802008-10-18 20:28:07 -070030 * hold rcu_read_lock() for read.
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070031 */
32
33struct dev_whitelist_item {
34 u32 major, minor;
35 short type;
36 short access;
37 struct list_head list;
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -070038 struct rcu_head rcu;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070039};
40
41struct dev_cgroup {
42 struct cgroup_subsys_state css;
43 struct list_head whitelist;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070044};
45
Pavel Emelyanovb66862f2008-06-05 22:46:24 -070046static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s)
47{
48 return container_of(s, struct dev_cgroup, css);
49}
50
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070051static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup)
52{
Pavel Emelyanovb66862f2008-06-05 22:46:24 -070053 return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id));
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070054}
55
Paul Menagef92523e2008-07-25 01:47:03 -070056static inline struct dev_cgroup *task_devcgroup(struct task_struct *task)
57{
58 return css_to_devcgroup(task_subsys_state(task, devices_subsys_id));
59}
60
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070061struct cgroup_subsys devices_subsys;
62
63static int devcgroup_can_attach(struct cgroup_subsys *ss,
64 struct cgroup *new_cgroup, struct task_struct *task)
65{
66 if (current != task && !capable(CAP_SYS_ADMIN))
67 return -EPERM;
68
69 return 0;
70}
71
72/*
Li Zefanb4046f02009-04-02 16:57:32 -070073 * called under devcgroup_mutex
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070074 */
75static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig)
76{
77 struct dev_whitelist_item *wh, *tmp, *new;
78
79 list_for_each_entry(wh, orig, list) {
Li Zefan2cdc7242008-10-18 20:28:06 -070080 new = kmemdup(wh, sizeof(*wh), GFP_KERNEL);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070081 if (!new)
82 goto free_and_exit;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070083 list_add_tail(&new->list, dest);
84 }
85
86 return 0;
87
88free_and_exit:
89 list_for_each_entry_safe(wh, tmp, dest, list) {
90 list_del(&wh->list);
91 kfree(wh);
92 }
93 return -ENOMEM;
94}
95
96/* Stupid prototype - don't bother combining existing entries */
97/*
Li Zefanb4046f02009-04-02 16:57:32 -070098 * called under devcgroup_mutex
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -070099 */
100static int dev_whitelist_add(struct dev_cgroup *dev_cgroup,
101 struct dev_whitelist_item *wh)
102{
Pavel Emelyanovd1ee2972008-06-05 22:46:28 -0700103 struct dev_whitelist_item *whcopy, *walk;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700104
Li Zefan2cdc7242008-10-18 20:28:06 -0700105 whcopy = kmemdup(wh, sizeof(*wh), GFP_KERNEL);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700106 if (!whcopy)
107 return -ENOMEM;
108
Pavel Emelyanovd1ee2972008-06-05 22:46:28 -0700109 list_for_each_entry(walk, &dev_cgroup->whitelist, list) {
110 if (walk->type != wh->type)
111 continue;
112 if (walk->major != wh->major)
113 continue;
114 if (walk->minor != wh->minor)
115 continue;
116
117 walk->access |= wh->access;
118 kfree(whcopy);
119 whcopy = NULL;
120 }
121
122 if (whcopy != NULL)
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700123 list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700124 return 0;
125}
126
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700127static void whitelist_item_free(struct rcu_head *rcu)
128{
129 struct dev_whitelist_item *item;
130
131 item = container_of(rcu, struct dev_whitelist_item, rcu);
132 kfree(item);
133}
134
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700135/*
Li Zefanb4046f02009-04-02 16:57:32 -0700136 * called under devcgroup_mutex
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700137 */
138static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup,
139 struct dev_whitelist_item *wh)
140{
141 struct dev_whitelist_item *walk, *tmp;
142
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700143 list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) {
144 if (walk->type == DEV_ALL)
145 goto remove;
146 if (walk->type != wh->type)
147 continue;
148 if (walk->major != ~0 && walk->major != wh->major)
149 continue;
150 if (walk->minor != ~0 && walk->minor != wh->minor)
151 continue;
152
153remove:
154 walk->access &= ~wh->access;
155 if (!walk->access) {
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700156 list_del_rcu(&walk->list);
157 call_rcu(&walk->rcu, whitelist_item_free);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700158 }
159 }
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700160}
161
162/*
163 * called from kernel/cgroup.c with cgroup_lock() held.
164 */
165static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss,
166 struct cgroup *cgroup)
167{
168 struct dev_cgroup *dev_cgroup, *parent_dev_cgroup;
169 struct cgroup *parent_cgroup;
170 int ret;
171
172 dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL);
173 if (!dev_cgroup)
174 return ERR_PTR(-ENOMEM);
175 INIT_LIST_HEAD(&dev_cgroup->whitelist);
176 parent_cgroup = cgroup->parent;
177
178 if (parent_cgroup == NULL) {
179 struct dev_whitelist_item *wh;
180 wh = kmalloc(sizeof(*wh), GFP_KERNEL);
181 if (!wh) {
182 kfree(dev_cgroup);
183 return ERR_PTR(-ENOMEM);
184 }
185 wh->minor = wh->major = ~0;
186 wh->type = DEV_ALL;
Li Zefan7759fc92008-07-25 01:47:08 -0700187 wh->access = ACC_MASK;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700188 list_add(&wh->list, &dev_cgroup->whitelist);
189 } else {
190 parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup);
Li Zefanb4046f02009-04-02 16:57:32 -0700191 mutex_lock(&devcgroup_mutex);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700192 ret = dev_whitelist_copy(&dev_cgroup->whitelist,
193 &parent_dev_cgroup->whitelist);
Li Zefanb4046f02009-04-02 16:57:32 -0700194 mutex_unlock(&devcgroup_mutex);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700195 if (ret) {
196 kfree(dev_cgroup);
197 return ERR_PTR(ret);
198 }
199 }
200
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700201 return &dev_cgroup->css;
202}
203
204static void devcgroup_destroy(struct cgroup_subsys *ss,
205 struct cgroup *cgroup)
206{
207 struct dev_cgroup *dev_cgroup;
208 struct dev_whitelist_item *wh, *tmp;
209
210 dev_cgroup = cgroup_to_devcgroup(cgroup);
211 list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) {
212 list_del(&wh->list);
213 kfree(wh);
214 }
215 kfree(dev_cgroup);
216}
217
218#define DEVCG_ALLOW 1
219#define DEVCG_DENY 2
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700220#define DEVCG_LIST 3
221
Li Zefan17d213f2008-07-13 12:14:02 -0700222#define MAJMINLEN 13
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700223#define ACCLEN 4
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700224
225static void set_access(char *acc, short access)
226{
227 int idx = 0;
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700228 memset(acc, 0, ACCLEN);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700229 if (access & ACC_READ)
230 acc[idx++] = 'r';
231 if (access & ACC_WRITE)
232 acc[idx++] = 'w';
233 if (access & ACC_MKNOD)
234 acc[idx++] = 'm';
235}
236
237static char type_to_char(short type)
238{
239 if (type == DEV_ALL)
240 return 'a';
241 if (type == DEV_CHAR)
242 return 'c';
243 if (type == DEV_BLOCK)
244 return 'b';
245 return 'X';
246}
247
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700248static void set_majmin(char *str, unsigned m)
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700249{
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700250 if (m == ~0)
Li Zefan7759fc92008-07-25 01:47:08 -0700251 strcpy(str, "*");
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700252 else
Li Zefan7759fc92008-07-25 01:47:08 -0700253 sprintf(str, "%u", m);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700254}
255
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700256static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
257 struct seq_file *m)
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700258{
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700259 struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700260 struct dev_whitelist_item *wh;
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700261 char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN];
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700262
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700263 rcu_read_lock();
264 list_for_each_entry_rcu(wh, &devcgroup->whitelist, list) {
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700265 set_access(acc, wh->access);
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700266 set_majmin(maj, wh->major);
267 set_majmin(min, wh->minor);
268 seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type),
269 maj, min, acc);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700270 }
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700271 rcu_read_unlock();
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700272
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700273 return 0;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700274}
275
276/*
277 * may_access_whitelist:
278 * does the access granted to dev_cgroup c contain the access
279 * requested in whitelist item refwh.
280 * return 1 if yes, 0 if no.
Li Zefanb4046f02009-04-02 16:57:32 -0700281 * call with devcgroup_mutex held
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700282 */
283static int may_access_whitelist(struct dev_cgroup *c,
284 struct dev_whitelist_item *refwh)
285{
286 struct dev_whitelist_item *whitem;
287
288 list_for_each_entry(whitem, &c->whitelist, list) {
289 if (whitem->type & DEV_ALL)
290 return 1;
291 if ((refwh->type & DEV_BLOCK) && !(whitem->type & DEV_BLOCK))
292 continue;
293 if ((refwh->type & DEV_CHAR) && !(whitem->type & DEV_CHAR))
294 continue;
295 if (whitem->major != ~0 && whitem->major != refwh->major)
296 continue;
297 if (whitem->minor != ~0 && whitem->minor != refwh->minor)
298 continue;
Li Zefanec229e82008-07-13 12:14:04 -0700299 if (refwh->access & (~whitem->access))
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700300 continue;
301 return 1;
302 }
303 return 0;
304}
305
306/*
307 * parent_has_perm:
308 * when adding a new allow rule to a device whitelist, the rule
309 * must be allowed in the parent device
310 */
Paul Menagef92523e2008-07-25 01:47:03 -0700311static int parent_has_perm(struct dev_cgroup *childcg,
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700312 struct dev_whitelist_item *wh)
313{
Paul Menagef92523e2008-07-25 01:47:03 -0700314 struct cgroup *pcg = childcg->css.cgroup->parent;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700315 struct dev_cgroup *parent;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700316
317 if (!pcg)
318 return 1;
319 parent = cgroup_to_devcgroup(pcg);
Lai Jiangshan47c59802008-10-18 20:28:07 -0700320 return may_access_whitelist(parent, wh);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700321}
322
323/*
324 * Modify the whitelist using allow/deny rules.
325 * CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD
326 * so we can give a container CAP_MKNOD to let it create devices but not
327 * modify the whitelist.
328 * It seems likely we'll want to add a CAP_CONTAINER capability to allow
329 * us to also grant CAP_SYS_ADMIN to containers without giving away the
330 * device whitelist controls, but for now we'll stick with CAP_SYS_ADMIN
331 *
332 * Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting
333 * new access is only allowed if you're in the top-level cgroup, or your
334 * parent cgroup has the access you're asking for.
335 */
Paul Menagef92523e2008-07-25 01:47:03 -0700336static int devcgroup_update_access(struct dev_cgroup *devcgroup,
337 int filetype, const char *buffer)
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700338{
Paul Menagef92523e2008-07-25 01:47:03 -0700339 const char *b;
Li Zefan7759fc92008-07-25 01:47:08 -0700340 char *endp;
Li Zefanc012a542008-10-18 20:28:07 -0700341 int count;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700342 struct dev_whitelist_item wh;
343
344 if (!capable(CAP_SYS_ADMIN))
345 return -EPERM;
346
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700347 memset(&wh, 0, sizeof(wh));
348 b = buffer;
349
350 switch (*b) {
351 case 'a':
352 wh.type = DEV_ALL;
353 wh.access = ACC_MASK;
Li Zefand823f6b2008-07-04 10:00:07 -0700354 wh.major = ~0;
355 wh.minor = ~0;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700356 goto handle;
357 case 'b':
358 wh.type = DEV_BLOCK;
359 break;
360 case 'c':
361 wh.type = DEV_CHAR;
362 break;
363 default:
Paul Menagef92523e2008-07-25 01:47:03 -0700364 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700365 }
366 b++;
Paul Menagef92523e2008-07-25 01:47:03 -0700367 if (!isspace(*b))
368 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700369 b++;
370 if (*b == '*') {
371 wh.major = ~0;
372 b++;
373 } else if (isdigit(*b)) {
Li Zefan7759fc92008-07-25 01:47:08 -0700374 wh.major = simple_strtoul(b, &endp, 10);
375 b = endp;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700376 } else {
Paul Menagef92523e2008-07-25 01:47:03 -0700377 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700378 }
Paul Menagef92523e2008-07-25 01:47:03 -0700379 if (*b != ':')
380 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700381 b++;
382
383 /* read minor */
384 if (*b == '*') {
385 wh.minor = ~0;
386 b++;
387 } else if (isdigit(*b)) {
Li Zefan7759fc92008-07-25 01:47:08 -0700388 wh.minor = simple_strtoul(b, &endp, 10);
389 b = endp;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700390 } else {
Paul Menagef92523e2008-07-25 01:47:03 -0700391 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700392 }
Paul Menagef92523e2008-07-25 01:47:03 -0700393 if (!isspace(*b))
394 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700395 for (b++, count = 0; count < 3; count++, b++) {
396 switch (*b) {
397 case 'r':
398 wh.access |= ACC_READ;
399 break;
400 case 'w':
401 wh.access |= ACC_WRITE;
402 break;
403 case 'm':
404 wh.access |= ACC_MKNOD;
405 break;
406 case '\n':
407 case '\0':
408 count = 3;
409 break;
410 default:
Paul Menagef92523e2008-07-25 01:47:03 -0700411 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700412 }
413 }
414
415handle:
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700416 switch (filetype) {
417 case DEVCG_ALLOW:
Paul Menagef92523e2008-07-25 01:47:03 -0700418 if (!parent_has_perm(devcgroup, &wh))
419 return -EPERM;
420 return dev_whitelist_add(devcgroup, &wh);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700421 case DEVCG_DENY:
422 dev_whitelist_rm(devcgroup, &wh);
423 break;
424 default:
Paul Menagef92523e2008-07-25 01:47:03 -0700425 return -EINVAL;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700426 }
Paul Menagef92523e2008-07-25 01:47:03 -0700427 return 0;
428}
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700429
Paul Menagef92523e2008-07-25 01:47:03 -0700430static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft,
431 const char *buffer)
432{
433 int retval;
Li Zefanb4046f02009-04-02 16:57:32 -0700434
435 mutex_lock(&devcgroup_mutex);
Paul Menagef92523e2008-07-25 01:47:03 -0700436 retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp),
437 cft->private, buffer);
Li Zefanb4046f02009-04-02 16:57:32 -0700438 mutex_unlock(&devcgroup_mutex);
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700439 return retval;
440}
441
442static struct cftype dev_cgroup_files[] = {
443 {
444 .name = "allow",
Paul Menagef92523e2008-07-25 01:47:03 -0700445 .write_string = devcgroup_access_write,
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700446 .private = DEVCG_ALLOW,
447 },
448 {
449 .name = "deny",
Paul Menagef92523e2008-07-25 01:47:03 -0700450 .write_string = devcgroup_access_write,
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700451 .private = DEVCG_DENY,
452 },
Serge E. Hallyn29486df2008-04-29 01:00:14 -0700453 {
454 .name = "list",
455 .read_seq_string = devcgroup_seq_read,
456 .private = DEVCG_LIST,
457 },
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700458};
459
460static int devcgroup_populate(struct cgroup_subsys *ss,
461 struct cgroup *cgroup)
462{
463 return cgroup_add_files(cgroup, ss, dev_cgroup_files,
464 ARRAY_SIZE(dev_cgroup_files));
465}
466
467struct cgroup_subsys devices_subsys = {
468 .name = "devices",
469 .can_attach = devcgroup_can_attach,
470 .create = devcgroup_create,
471 .destroy = devcgroup_destroy,
472 .populate = devcgroup_populate,
473 .subsys_id = devices_subsys_id,
474};
475
476int devcgroup_inode_permission(struct inode *inode, int mask)
477{
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700478 struct dev_cgroup *dev_cgroup;
479 struct dev_whitelist_item *wh;
480
481 dev_t device = inode->i_rdev;
482 if (!device)
483 return 0;
484 if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode))
485 return 0;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700486
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700487 rcu_read_lock();
Li Zefan36fd71d2008-09-02 14:35:52 -0700488
489 dev_cgroup = task_devcgroup(current);
490
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700491 list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700492 if (wh->type & DEV_ALL)
Li Zefancd500812009-06-17 16:26:33 -0700493 goto found;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700494 if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
495 continue;
496 if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode))
497 continue;
498 if (wh->major != ~0 && wh->major != imajor(inode))
499 continue;
500 if (wh->minor != ~0 && wh->minor != iminor(inode))
501 continue;
Li Zefancd500812009-06-17 16:26:33 -0700502
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700503 if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE))
504 continue;
505 if ((mask & MAY_READ) && !(wh->access & ACC_READ))
506 continue;
Li Zefancd500812009-06-17 16:26:33 -0700507found:
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700508 rcu_read_unlock();
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700509 return 0;
510 }
Li Zefan36fd71d2008-09-02 14:35:52 -0700511
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700512 rcu_read_unlock();
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700513
514 return -EPERM;
515}
516
517int devcgroup_inode_mknod(int mode, dev_t dev)
518{
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700519 struct dev_cgroup *dev_cgroup;
520 struct dev_whitelist_item *wh;
521
Serge E. Hallyn0b82ac32009-01-07 18:07:46 -0800522 if (!S_ISBLK(mode) && !S_ISCHR(mode))
523 return 0;
524
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700525 rcu_read_lock();
Li Zefan36fd71d2008-09-02 14:35:52 -0700526
527 dev_cgroup = task_devcgroup(current);
528
Lai Jiangshan116e0572009-01-07 18:07:45 -0800529 list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700530 if (wh->type & DEV_ALL)
Li Zefancd500812009-06-17 16:26:33 -0700531 goto found;
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700532 if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))
533 continue;
534 if ((wh->type & DEV_CHAR) && !S_ISCHR(mode))
535 continue;
536 if (wh->major != ~0 && wh->major != MAJOR(dev))
537 continue;
538 if (wh->minor != ~0 && wh->minor != MINOR(dev))
539 continue;
Li Zefancd500812009-06-17 16:26:33 -0700540
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700541 if (!(wh->access & ACC_MKNOD))
542 continue;
Li Zefancd500812009-06-17 16:26:33 -0700543found:
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700544 rcu_read_unlock();
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700545 return 0;
546 }
Li Zefan36fd71d2008-09-02 14:35:52 -0700547
Pavel Emelyanov4efd1a12008-07-25 01:47:07 -0700548 rcu_read_unlock();
Li Zefan36fd71d2008-09-02 14:35:52 -0700549
Serge E. Hallyn08ce5f12008-04-29 01:00:10 -0700550 return -EPERM;
551}