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Commit | Line | Data |
---|---|---|
08ce5f16 | 1 | /* |
47c59803 | 2 | * device_cgroup.c - device cgroup subsystem |
08ce5f16 SH |
3 | * |
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> | |
29486df3 | 12 | #include <linux/seq_file.h> |
5a0e3ad6 | 13 | #include <linux/slab.h> |
47c59803 | 14 | #include <linux/rcupdate.h> |
b4046f00 | 15 | #include <linux/mutex.h> |
08ce5f16 SH |
16 | |
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 | ||
b4046f00 LZ |
26 | static DEFINE_MUTEX(devcgroup_mutex); |
27 | ||
08ce5f16 SH |
28 | /* |
29 | * whitelist locking rules: | |
b4046f00 | 30 | * hold devcgroup_mutex for update/read. |
47c59803 | 31 | * hold rcu_read_lock() for read. |
08ce5f16 SH |
32 | */ |
33 | ||
34 | struct dev_whitelist_item { | |
35 | u32 major, minor; | |
36 | short type; | |
37 | short access; | |
38 | struct list_head list; | |
4efd1a1b | 39 | struct rcu_head rcu; |
08ce5f16 SH |
40 | }; |
41 | ||
42 | struct dev_cgroup { | |
43 | struct cgroup_subsys_state css; | |
44 | struct list_head whitelist; | |
66b8ef67 | 45 | bool deny_all; |
08ce5f16 SH |
46 | }; |
47 | ||
b66862f7 PE |
48 | static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s) |
49 | { | |
50 | return container_of(s, struct dev_cgroup, css); | |
51 | } | |
52 | ||
08ce5f16 SH |
53 | static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup) |
54 | { | |
b66862f7 | 55 | return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id)); |
08ce5f16 SH |
56 | } |
57 | ||
f92523e3 PM |
58 | static inline struct dev_cgroup *task_devcgroup(struct task_struct *task) |
59 | { | |
60 | return css_to_devcgroup(task_subsys_state(task, devices_subsys_id)); | |
61 | } | |
62 | ||
08ce5f16 SH |
63 | struct cgroup_subsys devices_subsys; |
64 | ||
761b3ef5 LZ |
65 | static int devcgroup_can_attach(struct cgroup *new_cgrp, |
66 | struct cgroup_taskset *set) | |
08ce5f16 | 67 | { |
2f7ee569 | 68 | struct task_struct *task = cgroup_taskset_first(set); |
08ce5f16 | 69 | |
2f7ee569 TH |
70 | if (current != task && !capable(CAP_SYS_ADMIN)) |
71 | return -EPERM; | |
08ce5f16 SH |
72 | return 0; |
73 | } | |
74 | ||
75 | /* | |
b4046f00 | 76 | * called under devcgroup_mutex |
08ce5f16 SH |
77 | */ |
78 | static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig) | |
79 | { | |
80 | struct dev_whitelist_item *wh, *tmp, *new; | |
81 | ||
82 | list_for_each_entry(wh, orig, list) { | |
2cdc7241 | 83 | new = kmemdup(wh, sizeof(*wh), GFP_KERNEL); |
08ce5f16 SH |
84 | if (!new) |
85 | goto free_and_exit; | |
08ce5f16 SH |
86 | list_add_tail(&new->list, dest); |
87 | } | |
88 | ||
89 | return 0; | |
90 | ||
91 | free_and_exit: | |
92 | list_for_each_entry_safe(wh, tmp, dest, list) { | |
93 | list_del(&wh->list); | |
94 | kfree(wh); | |
95 | } | |
96 | return -ENOMEM; | |
97 | } | |
98 | ||
08ce5f16 | 99 | /* |
b4046f00 | 100 | * called under devcgroup_mutex |
08ce5f16 SH |
101 | */ |
102 | static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, | |
103 | struct dev_whitelist_item *wh) | |
104 | { | |
d1ee2971 | 105 | struct dev_whitelist_item *whcopy, *walk; |
08ce5f16 | 106 | |
2cdc7241 | 107 | whcopy = kmemdup(wh, sizeof(*wh), GFP_KERNEL); |
08ce5f16 SH |
108 | if (!whcopy) |
109 | return -ENOMEM; | |
110 | ||
d1ee2971 PE |
111 | 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) | |
4efd1a1b | 125 | list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist); |
08ce5f16 SH |
126 | return 0; |
127 | } | |
128 | ||
129 | /* | |
b4046f00 | 130 | * called under devcgroup_mutex |
08ce5f16 SH |
131 | */ |
132 | static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup, | |
133 | struct dev_whitelist_item *wh) | |
134 | { | |
135 | struct dev_whitelist_item *walk, *tmp; | |
136 | ||
08ce5f16 | 137 | list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) { |
08ce5f16 SH |
138 | if (walk->type != wh->type) |
139 | continue; | |
ad676077 | 140 | if (walk->major != wh->major) |
08ce5f16 | 141 | continue; |
ad676077 | 142 | if (walk->minor != wh->minor) |
08ce5f16 SH |
143 | continue; |
144 | ||
08ce5f16 SH |
145 | walk->access &= ~wh->access; |
146 | if (!walk->access) { | |
4efd1a1b | 147 | list_del_rcu(&walk->list); |
6034f7e6 | 148 | kfree_rcu(walk, rcu); |
08ce5f16 SH |
149 | } |
150 | } | |
08ce5f16 SH |
151 | } |
152 | ||
868539a3 AR |
153 | /** |
154 | * dev_whitelist_clean - frees all entries of the whitelist | |
155 | * @dev_cgroup: dev_cgroup with the whitelist to be cleaned | |
156 | * | |
157 | * called under devcgroup_mutex | |
158 | */ | |
159 | static void dev_whitelist_clean(struct dev_cgroup *dev_cgroup) | |
160 | { | |
161 | struct dev_whitelist_item *wh, *tmp; | |
162 | ||
163 | list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) { | |
164 | list_del(&wh->list); | |
165 | kfree(wh); | |
166 | } | |
167 | } | |
168 | ||
08ce5f16 SH |
169 | /* |
170 | * called from kernel/cgroup.c with cgroup_lock() held. | |
171 | */ | |
761b3ef5 | 172 | static struct cgroup_subsys_state *devcgroup_create(struct cgroup *cgroup) |
08ce5f16 SH |
173 | { |
174 | struct dev_cgroup *dev_cgroup, *parent_dev_cgroup; | |
175 | struct cgroup *parent_cgroup; | |
176 | int ret; | |
177 | ||
178 | dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL); | |
179 | if (!dev_cgroup) | |
180 | return ERR_PTR(-ENOMEM); | |
181 | INIT_LIST_HEAD(&dev_cgroup->whitelist); | |
182 | parent_cgroup = cgroup->parent; | |
183 | ||
ad676077 | 184 | if (parent_cgroup == NULL) |
66b8ef67 | 185 | dev_cgroup->deny_all = false; |
ad676077 | 186 | else { |
08ce5f16 | 187 | parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup); |
b4046f00 | 188 | mutex_lock(&devcgroup_mutex); |
08ce5f16 SH |
189 | ret = dev_whitelist_copy(&dev_cgroup->whitelist, |
190 | &parent_dev_cgroup->whitelist); | |
66b8ef67 | 191 | dev_cgroup->deny_all = parent_dev_cgroup->deny_all; |
b4046f00 | 192 | mutex_unlock(&devcgroup_mutex); |
08ce5f16 SH |
193 | if (ret) { |
194 | kfree(dev_cgroup); | |
195 | return ERR_PTR(ret); | |
196 | } | |
197 | } | |
198 | ||
08ce5f16 SH |
199 | return &dev_cgroup->css; |
200 | } | |
201 | ||
761b3ef5 | 202 | static void devcgroup_destroy(struct cgroup *cgroup) |
08ce5f16 SH |
203 | { |
204 | struct dev_cgroup *dev_cgroup; | |
08ce5f16 SH |
205 | |
206 | dev_cgroup = cgroup_to_devcgroup(cgroup); | |
868539a3 | 207 | dev_whitelist_clean(dev_cgroup); |
08ce5f16 SH |
208 | kfree(dev_cgroup); |
209 | } | |
210 | ||
211 | #define DEVCG_ALLOW 1 | |
212 | #define DEVCG_DENY 2 | |
29486df3 SH |
213 | #define DEVCG_LIST 3 |
214 | ||
17d213f8 | 215 | #define MAJMINLEN 13 |
29486df3 | 216 | #define ACCLEN 4 |
08ce5f16 SH |
217 | |
218 | static void set_access(char *acc, short access) | |
219 | { | |
220 | int idx = 0; | |
29486df3 | 221 | memset(acc, 0, ACCLEN); |
08ce5f16 SH |
222 | if (access & ACC_READ) |
223 | acc[idx++] = 'r'; | |
224 | if (access & ACC_WRITE) | |
225 | acc[idx++] = 'w'; | |
226 | if (access & ACC_MKNOD) | |
227 | acc[idx++] = 'm'; | |
228 | } | |
229 | ||
230 | static char type_to_char(short type) | |
231 | { | |
232 | if (type == DEV_ALL) | |
233 | return 'a'; | |
234 | if (type == DEV_CHAR) | |
235 | return 'c'; | |
236 | if (type == DEV_BLOCK) | |
237 | return 'b'; | |
238 | return 'X'; | |
239 | } | |
240 | ||
29486df3 | 241 | static void set_majmin(char *str, unsigned m) |
08ce5f16 | 242 | { |
08ce5f16 | 243 | if (m == ~0) |
7759fc9d | 244 | strcpy(str, "*"); |
08ce5f16 | 245 | else |
7759fc9d | 246 | sprintf(str, "%u", m); |
08ce5f16 SH |
247 | } |
248 | ||
29486df3 SH |
249 | static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft, |
250 | struct seq_file *m) | |
08ce5f16 | 251 | { |
29486df3 | 252 | struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup); |
08ce5f16 | 253 | struct dev_whitelist_item *wh; |
29486df3 | 254 | char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN]; |
08ce5f16 | 255 | |
4efd1a1b | 256 | rcu_read_lock(); |
ad676077 AR |
257 | /* |
258 | * To preserve the compatibility: | |
259 | * - Only show the "all devices" when the default policy is to allow | |
260 | * - List the exceptions in case the default policy is to deny | |
261 | * This way, the file remains as a "whitelist of devices" | |
262 | */ | |
263 | if (devcgroup->deny_all == false) { | |
264 | set_access(acc, ACC_MASK); | |
265 | set_majmin(maj, ~0); | |
266 | set_majmin(min, ~0); | |
267 | seq_printf(m, "%c %s:%s %s\n", type_to_char(DEV_ALL), | |
29486df3 | 268 | maj, min, acc); |
ad676077 AR |
269 | } else { |
270 | list_for_each_entry_rcu(wh, &devcgroup->whitelist, list) { | |
271 | set_access(acc, wh->access); | |
272 | set_majmin(maj, wh->major); | |
273 | set_majmin(min, wh->minor); | |
274 | seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type), | |
275 | maj, min, acc); | |
276 | } | |
08ce5f16 | 277 | } |
4efd1a1b | 278 | rcu_read_unlock(); |
08ce5f16 | 279 | |
29486df3 | 280 | return 0; |
08ce5f16 SH |
281 | } |
282 | ||
ad676077 AR |
283 | /** |
284 | * may_access_whitelist - verifies if a new rule is part of what is allowed | |
285 | * by a dev cgroup based on the default policy + | |
286 | * exceptions. This is used to make sure a child cgroup | |
287 | * won't have more privileges than its parent or to | |
288 | * verify if a certain access is allowed. | |
289 | * @dev_cgroup: dev cgroup to be tested against | |
290 | * @refwh: new rule | |
08ce5f16 | 291 | */ |
ad676077 AR |
292 | static int may_access_whitelist(struct dev_cgroup *dev_cgroup, |
293 | struct dev_whitelist_item *refwh) | |
08ce5f16 SH |
294 | { |
295 | struct dev_whitelist_item *whitem; | |
ad676077 | 296 | bool match = false; |
08ce5f16 | 297 | |
ad676077 | 298 | list_for_each_entry(whitem, &dev_cgroup->whitelist, list) { |
08ce5f16 SH |
299 | if ((refwh->type & DEV_BLOCK) && !(whitem->type & DEV_BLOCK)) |
300 | continue; | |
301 | if ((refwh->type & DEV_CHAR) && !(whitem->type & DEV_CHAR)) | |
302 | continue; | |
303 | if (whitem->major != ~0 && whitem->major != refwh->major) | |
304 | continue; | |
305 | if (whitem->minor != ~0 && whitem->minor != refwh->minor) | |
306 | continue; | |
ec229e83 | 307 | if (refwh->access & (~whitem->access)) |
08ce5f16 | 308 | continue; |
ad676077 AR |
309 | match = true; |
310 | break; | |
08ce5f16 | 311 | } |
ad676077 AR |
312 | |
313 | /* | |
314 | * In two cases we'll consider this new rule valid: | |
315 | * - the dev cgroup has its default policy to allow + exception list: | |
316 | * the new rule should *not* match any of the exceptions | |
317 | * (!deny_all, !match) | |
318 | * - the dev cgroup has its default policy to deny + exception list: | |
319 | * the new rule *should* match the exceptions | |
320 | * (deny_all, match) | |
321 | */ | |
322 | if (dev_cgroup->deny_all == match) | |
323 | return 1; | |
08ce5f16 SH |
324 | return 0; |
325 | } | |
326 | ||
327 | /* | |
328 | * parent_has_perm: | |
329 | * when adding a new allow rule to a device whitelist, the rule | |
330 | * must be allowed in the parent device | |
331 | */ | |
f92523e3 | 332 | static int parent_has_perm(struct dev_cgroup *childcg, |
08ce5f16 SH |
333 | struct dev_whitelist_item *wh) |
334 | { | |
f92523e3 | 335 | struct cgroup *pcg = childcg->css.cgroup->parent; |
08ce5f16 | 336 | struct dev_cgroup *parent; |
08ce5f16 SH |
337 | |
338 | if (!pcg) | |
339 | return 1; | |
340 | parent = cgroup_to_devcgroup(pcg); | |
47c59803 | 341 | return may_access_whitelist(parent, wh); |
08ce5f16 SH |
342 | } |
343 | ||
344 | /* | |
345 | * Modify the whitelist using allow/deny rules. | |
346 | * CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD | |
347 | * so we can give a container CAP_MKNOD to let it create devices but not | |
348 | * modify the whitelist. | |
349 | * It seems likely we'll want to add a CAP_CONTAINER capability to allow | |
350 | * us to also grant CAP_SYS_ADMIN to containers without giving away the | |
351 | * device whitelist controls, but for now we'll stick with CAP_SYS_ADMIN | |
352 | * | |
353 | * Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting | |
354 | * new access is only allowed if you're in the top-level cgroup, or your | |
355 | * parent cgroup has the access you're asking for. | |
356 | */ | |
f92523e3 PM |
357 | static int devcgroup_update_access(struct dev_cgroup *devcgroup, |
358 | int filetype, const char *buffer) | |
08ce5f16 | 359 | { |
f92523e3 | 360 | const char *b; |
7759fc9d | 361 | char *endp; |
c012a54a | 362 | int count; |
08ce5f16 SH |
363 | struct dev_whitelist_item wh; |
364 | ||
365 | if (!capable(CAP_SYS_ADMIN)) | |
366 | return -EPERM; | |
367 | ||
08ce5f16 SH |
368 | memset(&wh, 0, sizeof(wh)); |
369 | b = buffer; | |
370 | ||
371 | switch (*b) { | |
372 | case 'a': | |
ad676077 AR |
373 | switch (filetype) { |
374 | case DEVCG_ALLOW: | |
375 | if (!parent_has_perm(devcgroup, &wh)) | |
376 | return -EPERM; | |
377 | dev_whitelist_clean(devcgroup); | |
378 | devcgroup->deny_all = false; | |
379 | break; | |
380 | case DEVCG_DENY: | |
381 | dev_whitelist_clean(devcgroup); | |
382 | devcgroup->deny_all = true; | |
383 | break; | |
384 | default: | |
385 | return -EINVAL; | |
386 | } | |
387 | return 0; | |
08ce5f16 SH |
388 | case 'b': |
389 | wh.type = DEV_BLOCK; | |
390 | break; | |
391 | case 'c': | |
392 | wh.type = DEV_CHAR; | |
393 | break; | |
394 | default: | |
f92523e3 | 395 | return -EINVAL; |
08ce5f16 SH |
396 | } |
397 | b++; | |
f92523e3 PM |
398 | if (!isspace(*b)) |
399 | return -EINVAL; | |
08ce5f16 SH |
400 | b++; |
401 | if (*b == '*') { | |
402 | wh.major = ~0; | |
403 | b++; | |
404 | } else if (isdigit(*b)) { | |
7759fc9d LZ |
405 | wh.major = simple_strtoul(b, &endp, 10); |
406 | b = endp; | |
08ce5f16 | 407 | } else { |
f92523e3 | 408 | return -EINVAL; |
08ce5f16 | 409 | } |
f92523e3 PM |
410 | if (*b != ':') |
411 | return -EINVAL; | |
08ce5f16 SH |
412 | b++; |
413 | ||
414 | /* read minor */ | |
415 | if (*b == '*') { | |
416 | wh.minor = ~0; | |
417 | b++; | |
418 | } else if (isdigit(*b)) { | |
7759fc9d LZ |
419 | wh.minor = simple_strtoul(b, &endp, 10); |
420 | b = endp; | |
08ce5f16 | 421 | } else { |
f92523e3 | 422 | return -EINVAL; |
08ce5f16 | 423 | } |
f92523e3 PM |
424 | if (!isspace(*b)) |
425 | return -EINVAL; | |
08ce5f16 SH |
426 | for (b++, count = 0; count < 3; count++, b++) { |
427 | switch (*b) { | |
428 | case 'r': | |
429 | wh.access |= ACC_READ; | |
430 | break; | |
431 | case 'w': | |
432 | wh.access |= ACC_WRITE; | |
433 | break; | |
434 | case 'm': | |
435 | wh.access |= ACC_MKNOD; | |
436 | break; | |
437 | case '\n': | |
438 | case '\0': | |
439 | count = 3; | |
440 | break; | |
441 | default: | |
f92523e3 | 442 | return -EINVAL; |
08ce5f16 SH |
443 | } |
444 | } | |
445 | ||
08ce5f16 SH |
446 | switch (filetype) { |
447 | case DEVCG_ALLOW: | |
f92523e3 PM |
448 | if (!parent_has_perm(devcgroup, &wh)) |
449 | return -EPERM; | |
ad676077 AR |
450 | /* |
451 | * If the default policy is to allow by default, try to remove | |
452 | * an matching exception instead. And be silent about it: we | |
453 | * don't want to break compatibility | |
454 | */ | |
455 | if (devcgroup->deny_all == false) { | |
456 | dev_whitelist_rm(devcgroup, &wh); | |
457 | return 0; | |
458 | } | |
f92523e3 | 459 | return dev_whitelist_add(devcgroup, &wh); |
08ce5f16 | 460 | case DEVCG_DENY: |
ad676077 AR |
461 | /* |
462 | * If the default policy is to deny by default, try to remove | |
463 | * an matching exception instead. And be silent about it: we | |
464 | * don't want to break compatibility | |
465 | */ | |
466 | if (devcgroup->deny_all == true) { | |
467 | dev_whitelist_rm(devcgroup, &wh); | |
468 | return 0; | |
469 | } | |
470 | return dev_whitelist_add(devcgroup, &wh); | |
08ce5f16 | 471 | default: |
f92523e3 | 472 | return -EINVAL; |
08ce5f16 | 473 | } |
f92523e3 PM |
474 | return 0; |
475 | } | |
08ce5f16 | 476 | |
f92523e3 PM |
477 | static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft, |
478 | const char *buffer) | |
479 | { | |
480 | int retval; | |
b4046f00 LZ |
481 | |
482 | mutex_lock(&devcgroup_mutex); | |
f92523e3 PM |
483 | retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp), |
484 | cft->private, buffer); | |
b4046f00 | 485 | mutex_unlock(&devcgroup_mutex); |
08ce5f16 SH |
486 | return retval; |
487 | } | |
488 | ||
489 | static struct cftype dev_cgroup_files[] = { | |
490 | { | |
491 | .name = "allow", | |
f92523e3 | 492 | .write_string = devcgroup_access_write, |
08ce5f16 SH |
493 | .private = DEVCG_ALLOW, |
494 | }, | |
495 | { | |
496 | .name = "deny", | |
f92523e3 | 497 | .write_string = devcgroup_access_write, |
08ce5f16 SH |
498 | .private = DEVCG_DENY, |
499 | }, | |
29486df3 SH |
500 | { |
501 | .name = "list", | |
502 | .read_seq_string = devcgroup_seq_read, | |
503 | .private = DEVCG_LIST, | |
504 | }, | |
4baf6e33 | 505 | { } /* terminate */ |
08ce5f16 SH |
506 | }; |
507 | ||
08ce5f16 SH |
508 | struct cgroup_subsys devices_subsys = { |
509 | .name = "devices", | |
510 | .can_attach = devcgroup_can_attach, | |
511 | .create = devcgroup_create, | |
c5b60b5e | 512 | .destroy = devcgroup_destroy, |
08ce5f16 | 513 | .subsys_id = devices_subsys_id, |
4baf6e33 | 514 | .base_cftypes = dev_cgroup_files, |
8c7f6edb TH |
515 | |
516 | /* | |
517 | * While devices cgroup has the rudimentary hierarchy support which | |
518 | * checks the parent's restriction, it doesn't properly propagates | |
519 | * config changes in ancestors to their descendents. A child | |
520 | * should only be allowed to add more restrictions to the parent's | |
521 | * configuration. Fix it and remove the following. | |
522 | */ | |
523 | .broken_hierarchy = true, | |
08ce5f16 SH |
524 | }; |
525 | ||
ad676077 AR |
526 | /** |
527 | * __devcgroup_check_permission - checks if an inode operation is permitted | |
528 | * @dev_cgroup: the dev cgroup to be tested against | |
529 | * @type: device type | |
530 | * @major: device major number | |
531 | * @minor: device minor number | |
532 | * @access: combination of ACC_WRITE, ACC_READ and ACC_MKNOD | |
533 | * | |
534 | * returns 0 on success, -EPERM case the operation is not permitted | |
535 | */ | |
536 | static int __devcgroup_check_permission(struct dev_cgroup *dev_cgroup, | |
537 | short type, u32 major, u32 minor, | |
538 | short access) | |
08ce5f16 | 539 | { |
ad676077 AR |
540 | struct dev_whitelist_item wh; |
541 | int rc; | |
36fd71d2 | 542 | |
ad676077 AR |
543 | memset(&wh, 0, sizeof(wh)); |
544 | wh.type = type; | |
545 | wh.major = major; | |
546 | wh.minor = minor; | |
547 | wh.access = access; | |
36fd71d2 | 548 | |
ad676077 AR |
549 | rcu_read_lock(); |
550 | rc = may_access_whitelist(dev_cgroup, &wh); | |
551 | rcu_read_unlock(); | |
cd500819 | 552 | |
ad676077 AR |
553 | if (!rc) |
554 | return -EPERM; | |
36fd71d2 | 555 | |
ad676077 AR |
556 | return 0; |
557 | } | |
08ce5f16 | 558 | |
ad676077 AR |
559 | int __devcgroup_inode_permission(struct inode *inode, int mask) |
560 | { | |
561 | struct dev_cgroup *dev_cgroup = task_devcgroup(current); | |
562 | short type, access = 0; | |
563 | ||
564 | if (S_ISBLK(inode->i_mode)) | |
565 | type = DEV_BLOCK; | |
566 | if (S_ISCHR(inode->i_mode)) | |
567 | type = DEV_CHAR; | |
568 | if (mask & MAY_WRITE) | |
569 | access |= ACC_WRITE; | |
570 | if (mask & MAY_READ) | |
571 | access |= ACC_READ; | |
572 | ||
573 | return __devcgroup_check_permission(dev_cgroup, type, imajor(inode), | |
574 | iminor(inode), access); | |
08ce5f16 SH |
575 | } |
576 | ||
577 | int devcgroup_inode_mknod(int mode, dev_t dev) | |
578 | { | |
ad676077 AR |
579 | struct dev_cgroup *dev_cgroup = task_devcgroup(current); |
580 | short type; | |
08ce5f16 | 581 | |
0b82ac37 SH |
582 | if (!S_ISBLK(mode) && !S_ISCHR(mode)) |
583 | return 0; | |
584 | ||
ad676077 AR |
585 | if (S_ISBLK(mode)) |
586 | type = DEV_BLOCK; | |
587 | else | |
588 | type = DEV_CHAR; | |
36fd71d2 | 589 | |
ad676077 AR |
590 | return __devcgroup_check_permission(dev_cgroup, type, MAJOR(dev), |
591 | MINOR(dev), ACC_MKNOD); | |
36fd71d2 | 592 | |
08ce5f16 | 593 | } |