1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * device_cgroup.c - device cgroup subsystem 2 * device_cgroup.c - device cgroup subsystem
4 * 3 *
5 * Copyright 2007 IBM Corp 4 * Copyright 2007 IBM Corp
6 */ 5 */
7 6
8 #include <linux/bpf-cgroup.h> <<
9 #include <linux/device_cgroup.h> 7 #include <linux/device_cgroup.h>
10 #include <linux/cgroup.h> 8 #include <linux/cgroup.h>
11 #include <linux/ctype.h> 9 #include <linux/ctype.h>
12 #include <linux/list.h> 10 #include <linux/list.h>
13 #include <linux/uaccess.h> 11 #include <linux/uaccess.h>
14 #include <linux/seq_file.h> 12 #include <linux/seq_file.h>
15 #include <linux/slab.h> 13 #include <linux/slab.h>
16 #include <linux/rcupdate.h> 14 #include <linux/rcupdate.h>
17 #include <linux/mutex.h> 15 #include <linux/mutex.h>
18 16
19 #ifdef CONFIG_CGROUP_DEVICE !! 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 */
20 25
21 static DEFINE_MUTEX(devcgroup_mutex); 26 static DEFINE_MUTEX(devcgroup_mutex);
22 27
23 enum devcg_behavior { 28 enum devcg_behavior {
24 DEVCG_DEFAULT_NONE, 29 DEVCG_DEFAULT_NONE,
25 DEVCG_DEFAULT_ALLOW, 30 DEVCG_DEFAULT_ALLOW,
26 DEVCG_DEFAULT_DENY, 31 DEVCG_DEFAULT_DENY,
27 }; 32 };
28 33
29 /* 34 /*
30 * exception list locking rules: 35 * exception list locking rules:
31 * hold devcgroup_mutex for update/read. 36 * hold devcgroup_mutex for update/read.
32 * hold rcu_read_lock() for read. 37 * hold rcu_read_lock() for read.
33 */ 38 */
34 39
35 struct dev_exception_item { 40 struct dev_exception_item {
36 u32 major, minor; 41 u32 major, minor;
37 short type; 42 short type;
38 short access; 43 short access;
39 struct list_head list; 44 struct list_head list;
40 struct rcu_head rcu; 45 struct rcu_head rcu;
41 }; 46 };
42 47
43 struct dev_cgroup { 48 struct dev_cgroup {
44 struct cgroup_subsys_state css; 49 struct cgroup_subsys_state css;
45 struct list_head exceptions; 50 struct list_head exceptions;
46 enum devcg_behavior behavior; 51 enum devcg_behavior behavior;
>> 52 /* temporary list for pending propagation operations */
>> 53 struct list_head propagate_pending;
47 }; 54 };
48 55
49 static inline struct dev_cgroup *css_to_devcgr 56 static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s)
50 { 57 {
51 return s ? container_of(s, struct dev_ !! 58 return container_of(s, struct dev_cgroup, css);
>> 59 }
>> 60
>> 61 static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup)
>> 62 {
>> 63 return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id));
52 } 64 }
53 65
54 static inline struct dev_cgroup *task_devcgrou 66 static inline struct dev_cgroup *task_devcgroup(struct task_struct *task)
55 { 67 {
56 return css_to_devcgroup(task_css(task, !! 68 return css_to_devcgroup(task_subsys_state(task, devices_subsys_id));
>> 69 }
>> 70
>> 71 struct cgroup_subsys devices_subsys;
>> 72
>> 73 static int devcgroup_can_attach(struct cgroup *new_cgrp,
>> 74 struct cgroup_taskset *set)
>> 75 {
>> 76 struct task_struct *task = cgroup_taskset_first(set);
>> 77
>> 78 if (current != task && !capable(CAP_SYS_ADMIN))
>> 79 return -EPERM;
>> 80 return 0;
57 } 81 }
58 82
59 /* 83 /*
60 * called under devcgroup_mutex 84 * called under devcgroup_mutex
61 */ 85 */
62 static int dev_exceptions_copy(struct list_hea 86 static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig)
63 { 87 {
64 struct dev_exception_item *ex, *tmp, * 88 struct dev_exception_item *ex, *tmp, *new;
65 89
66 lockdep_assert_held(&devcgroup_mutex); 90 lockdep_assert_held(&devcgroup_mutex);
67 91
68 list_for_each_entry(ex, orig, list) { 92 list_for_each_entry(ex, orig, list) {
69 new = kmemdup(ex, sizeof(*ex), 93 new = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
70 if (!new) 94 if (!new)
71 goto free_and_exit; 95 goto free_and_exit;
72 list_add_tail(&new->list, dest 96 list_add_tail(&new->list, dest);
73 } 97 }
74 98
75 return 0; 99 return 0;
76 100
77 free_and_exit: 101 free_and_exit:
78 list_for_each_entry_safe(ex, tmp, dest 102 list_for_each_entry_safe(ex, tmp, dest, list) {
79 list_del(&ex->list); 103 list_del(&ex->list);
80 kfree(ex); 104 kfree(ex);
81 } 105 }
82 return -ENOMEM; 106 return -ENOMEM;
83 } 107 }
84 108
85 static void dev_exceptions_move(struct list_he <<
86 { <<
87 struct dev_exception_item *ex, *tmp; <<
88 <<
89 lockdep_assert_held(&devcgroup_mutex); <<
90 <<
91 list_for_each_entry_safe(ex, tmp, orig <<
92 list_move_tail(&ex->list, dest <<
93 } <<
94 } <<
95 <<
96 /* 109 /*
97 * called under devcgroup_mutex 110 * called under devcgroup_mutex
98 */ 111 */
99 static int dev_exception_add(struct dev_cgroup 112 static int dev_exception_add(struct dev_cgroup *dev_cgroup,
100 struct dev_except 113 struct dev_exception_item *ex)
101 { 114 {
102 struct dev_exception_item *excopy, *wa 115 struct dev_exception_item *excopy, *walk;
103 116
104 lockdep_assert_held(&devcgroup_mutex); 117 lockdep_assert_held(&devcgroup_mutex);
105 118
106 excopy = kmemdup(ex, sizeof(*ex), GFP_ 119 excopy = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
107 if (!excopy) 120 if (!excopy)
108 return -ENOMEM; 121 return -ENOMEM;
109 122
110 list_for_each_entry(walk, &dev_cgroup- 123 list_for_each_entry(walk, &dev_cgroup->exceptions, list) {
111 if (walk->type != ex->type) 124 if (walk->type != ex->type)
112 continue; 125 continue;
113 if (walk->major != ex->major) 126 if (walk->major != ex->major)
114 continue; 127 continue;
115 if (walk->minor != ex->minor) 128 if (walk->minor != ex->minor)
116 continue; 129 continue;
117 130
118 walk->access |= ex->access; 131 walk->access |= ex->access;
119 kfree(excopy); 132 kfree(excopy);
120 excopy = NULL; 133 excopy = NULL;
121 } 134 }
122 135
123 if (excopy != NULL) 136 if (excopy != NULL)
124 list_add_tail_rcu(&excopy->lis 137 list_add_tail_rcu(&excopy->list, &dev_cgroup->exceptions);
125 return 0; 138 return 0;
126 } 139 }
127 140
128 /* 141 /*
129 * called under devcgroup_mutex 142 * called under devcgroup_mutex
130 */ 143 */
131 static void dev_exception_rm(struct dev_cgroup 144 static void dev_exception_rm(struct dev_cgroup *dev_cgroup,
132 struct dev_except 145 struct dev_exception_item *ex)
133 { 146 {
134 struct dev_exception_item *walk, *tmp; 147 struct dev_exception_item *walk, *tmp;
135 148
136 lockdep_assert_held(&devcgroup_mutex); 149 lockdep_assert_held(&devcgroup_mutex);
137 150
138 list_for_each_entry_safe(walk, tmp, &d 151 list_for_each_entry_safe(walk, tmp, &dev_cgroup->exceptions, list) {
139 if (walk->type != ex->type) 152 if (walk->type != ex->type)
140 continue; 153 continue;
141 if (walk->major != ex->major) 154 if (walk->major != ex->major)
142 continue; 155 continue;
143 if (walk->minor != ex->minor) 156 if (walk->minor != ex->minor)
144 continue; 157 continue;
145 158
146 walk->access &= ~ex->access; 159 walk->access &= ~ex->access;
147 if (!walk->access) { 160 if (!walk->access) {
148 list_del_rcu(&walk->li 161 list_del_rcu(&walk->list);
149 kfree_rcu(walk, rcu); 162 kfree_rcu(walk, rcu);
150 } 163 }
151 } 164 }
152 } 165 }
153 166
154 static void __dev_exception_clean(struct dev_c 167 static void __dev_exception_clean(struct dev_cgroup *dev_cgroup)
155 { 168 {
156 struct dev_exception_item *ex, *tmp; 169 struct dev_exception_item *ex, *tmp;
157 170
158 list_for_each_entry_safe(ex, tmp, &dev 171 list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
159 list_del_rcu(&ex->list); 172 list_del_rcu(&ex->list);
160 kfree_rcu(ex, rcu); 173 kfree_rcu(ex, rcu);
161 } 174 }
162 } 175 }
163 176
164 /** 177 /**
165 * dev_exception_clean - frees all entries of 178 * dev_exception_clean - frees all entries of the exception list
166 * @dev_cgroup: dev_cgroup with the exception 179 * @dev_cgroup: dev_cgroup with the exception list to be cleaned
167 * 180 *
168 * called under devcgroup_mutex 181 * called under devcgroup_mutex
169 */ 182 */
170 static void dev_exception_clean(struct dev_cgr 183 static void dev_exception_clean(struct dev_cgroup *dev_cgroup)
171 { 184 {
172 lockdep_assert_held(&devcgroup_mutex); 185 lockdep_assert_held(&devcgroup_mutex);
173 186
174 __dev_exception_clean(dev_cgroup); 187 __dev_exception_clean(dev_cgroup);
175 } 188 }
176 189
177 static inline bool is_devcg_online(const struc 190 static inline bool is_devcg_online(const struct dev_cgroup *devcg)
178 { 191 {
179 return (devcg->behavior != DEVCG_DEFAU 192 return (devcg->behavior != DEVCG_DEFAULT_NONE);
180 } 193 }
181 194
182 /** 195 /**
183 * devcgroup_online - initializes devcgroup's 196 * devcgroup_online - initializes devcgroup's behavior and exceptions based on
184 * parent's 197 * parent's
185 * @css: css getting online !! 198 * @cgroup: cgroup getting online
186 * returns 0 in case of success, error code ot 199 * returns 0 in case of success, error code otherwise
187 */ 200 */
188 static int devcgroup_online(struct cgroup_subs !! 201 static int devcgroup_online(struct cgroup *cgroup)
189 { 202 {
190 struct dev_cgroup *dev_cgroup = css_to !! 203 struct dev_cgroup *dev_cgroup, *parent_dev_cgroup = NULL;
191 struct dev_cgroup *parent_dev_cgroup = <<
192 int ret = 0; 204 int ret = 0;
193 205
194 mutex_lock(&devcgroup_mutex); 206 mutex_lock(&devcgroup_mutex);
>> 207 dev_cgroup = cgroup_to_devcgroup(cgroup);
>> 208 if (cgroup->parent)
>> 209 parent_dev_cgroup = cgroup_to_devcgroup(cgroup->parent);
195 210
196 if (parent_dev_cgroup == NULL) 211 if (parent_dev_cgroup == NULL)
197 dev_cgroup->behavior = DEVCG_D 212 dev_cgroup->behavior = DEVCG_DEFAULT_ALLOW;
198 else { 213 else {
199 ret = dev_exceptions_copy(&dev 214 ret = dev_exceptions_copy(&dev_cgroup->exceptions,
200 &par 215 &parent_dev_cgroup->exceptions);
201 if (!ret) 216 if (!ret)
202 dev_cgroup->behavior = 217 dev_cgroup->behavior = parent_dev_cgroup->behavior;
203 } 218 }
204 mutex_unlock(&devcgroup_mutex); 219 mutex_unlock(&devcgroup_mutex);
205 220
206 return ret; 221 return ret;
207 } 222 }
208 223
209 static void devcgroup_offline(struct cgroup_su !! 224 static void devcgroup_offline(struct cgroup *cgroup)
210 { 225 {
211 struct dev_cgroup *dev_cgroup = css_to !! 226 struct dev_cgroup *dev_cgroup = cgroup_to_devcgroup(cgroup);
212 227
213 mutex_lock(&devcgroup_mutex); 228 mutex_lock(&devcgroup_mutex);
214 dev_cgroup->behavior = DEVCG_DEFAULT_N 229 dev_cgroup->behavior = DEVCG_DEFAULT_NONE;
215 mutex_unlock(&devcgroup_mutex); 230 mutex_unlock(&devcgroup_mutex);
216 } 231 }
217 232
218 /* 233 /*
219 * called from kernel/cgroup/cgroup.c with cgr !! 234 * called from kernel/cgroup.c with cgroup_lock() held.
220 */ 235 */
221 static struct cgroup_subsys_state * !! 236 static struct cgroup_subsys_state *devcgroup_css_alloc(struct cgroup *cgroup)
222 devcgroup_css_alloc(struct cgroup_subsys_state <<
223 { 237 {
224 struct dev_cgroup *dev_cgroup; 238 struct dev_cgroup *dev_cgroup;
225 239
226 dev_cgroup = kzalloc(sizeof(*dev_cgrou 240 dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL);
227 if (!dev_cgroup) 241 if (!dev_cgroup)
228 return ERR_PTR(-ENOMEM); 242 return ERR_PTR(-ENOMEM);
229 INIT_LIST_HEAD(&dev_cgroup->exceptions 243 INIT_LIST_HEAD(&dev_cgroup->exceptions);
>> 244 INIT_LIST_HEAD(&dev_cgroup->propagate_pending);
230 dev_cgroup->behavior = DEVCG_DEFAULT_N 245 dev_cgroup->behavior = DEVCG_DEFAULT_NONE;
231 246
232 return &dev_cgroup->css; 247 return &dev_cgroup->css;
233 } 248 }
234 249
235 static void devcgroup_css_free(struct cgroup_s !! 250 static void devcgroup_css_free(struct cgroup *cgroup)
236 { 251 {
237 struct dev_cgroup *dev_cgroup = css_to !! 252 struct dev_cgroup *dev_cgroup;
238 253
>> 254 dev_cgroup = cgroup_to_devcgroup(cgroup);
239 __dev_exception_clean(dev_cgroup); 255 __dev_exception_clean(dev_cgroup);
240 kfree(dev_cgroup); 256 kfree(dev_cgroup);
241 } 257 }
242 258
243 #define DEVCG_ALLOW 1 259 #define DEVCG_ALLOW 1
244 #define DEVCG_DENY 2 260 #define DEVCG_DENY 2
245 #define DEVCG_LIST 3 261 #define DEVCG_LIST 3
246 262
247 #define MAJMINLEN 13 263 #define MAJMINLEN 13
248 #define ACCLEN 4 264 #define ACCLEN 4
249 265
250 static void set_access(char *acc, short access 266 static void set_access(char *acc, short access)
251 { 267 {
252 int idx = 0; 268 int idx = 0;
253 memset(acc, 0, ACCLEN); 269 memset(acc, 0, ACCLEN);
254 if (access & DEVCG_ACC_READ) !! 270 if (access & ACC_READ)
255 acc[idx++] = 'r'; 271 acc[idx++] = 'r';
256 if (access & DEVCG_ACC_WRITE) !! 272 if (access & ACC_WRITE)
257 acc[idx++] = 'w'; 273 acc[idx++] = 'w';
258 if (access & DEVCG_ACC_MKNOD) !! 274 if (access & ACC_MKNOD)
259 acc[idx++] = 'm'; 275 acc[idx++] = 'm';
260 } 276 }
261 277
262 static char type_to_char(short type) 278 static char type_to_char(short type)
263 { 279 {
264 if (type == DEVCG_DEV_ALL) !! 280 if (type == DEV_ALL)
265 return 'a'; 281 return 'a';
266 if (type == DEVCG_DEV_CHAR) !! 282 if (type == DEV_CHAR)
267 return 'c'; 283 return 'c';
268 if (type == DEVCG_DEV_BLOCK) !! 284 if (type == DEV_BLOCK)
269 return 'b'; 285 return 'b';
270 return 'X'; 286 return 'X';
271 } 287 }
272 288
273 static void set_majmin(char *str, unsigned m) 289 static void set_majmin(char *str, unsigned m)
274 { 290 {
275 if (m == ~0) 291 if (m == ~0)
276 strcpy(str, "*"); 292 strcpy(str, "*");
277 else 293 else
278 sprintf(str, "%u", m); 294 sprintf(str, "%u", m);
279 } 295 }
280 296
281 static int devcgroup_seq_show(struct seq_file !! 297 static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft,
>> 298 struct seq_file *m)
282 { 299 {
283 struct dev_cgroup *devcgroup = css_to_ !! 300 struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup);
284 struct dev_exception_item *ex; 301 struct dev_exception_item *ex;
285 char maj[MAJMINLEN], min[MAJMINLEN], a 302 char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN];
286 303
287 rcu_read_lock(); 304 rcu_read_lock();
288 /* 305 /*
289 * To preserve the compatibility: 306 * To preserve the compatibility:
290 * - Only show the "all devices" when 307 * - Only show the "all devices" when the default policy is to allow
291 * - List the exceptions in case the d 308 * - List the exceptions in case the default policy is to deny
292 * This way, the file remains as a "wh 309 * This way, the file remains as a "whitelist of devices"
293 */ 310 */
294 if (devcgroup->behavior == DEVCG_DEFAU 311 if (devcgroup->behavior == DEVCG_DEFAULT_ALLOW) {
295 set_access(acc, DEVCG_ACC_MASK !! 312 set_access(acc, ACC_MASK);
296 set_majmin(maj, ~0); 313 set_majmin(maj, ~0);
297 set_majmin(min, ~0); 314 set_majmin(min, ~0);
298 seq_printf(m, "%c %s:%s %s\n", !! 315 seq_printf(m, "%c %s:%s %s\n", type_to_char(DEV_ALL),
299 maj, min, acc); 316 maj, min, acc);
300 } else { 317 } else {
301 list_for_each_entry_rcu(ex, &d 318 list_for_each_entry_rcu(ex, &devcgroup->exceptions, list) {
302 set_access(acc, ex->ac 319 set_access(acc, ex->access);
303 set_majmin(maj, ex->ma 320 set_majmin(maj, ex->major);
304 set_majmin(min, ex->mi 321 set_majmin(min, ex->minor);
305 seq_printf(m, "%c %s:% 322 seq_printf(m, "%c %s:%s %s\n", type_to_char(ex->type),
306 maj, min, a 323 maj, min, acc);
307 } 324 }
308 } 325 }
309 rcu_read_unlock(); 326 rcu_read_unlock();
310 327
311 return 0; 328 return 0;
312 } 329 }
313 330
314 /** 331 /**
315 * match_exception - iterates the excepti !! 332 * may_access - verifies if a new exception is part of what is allowed
316 * @exceptions: list of exceptions !! 333 * by a dev cgroup based on the default policy +
317 * @type: device type (DEVCG_DEV_BLOCK or DEVC !! 334 * exceptions. This is used to make sure a child cgroup
318 * @major: device file major number, ~0 to mat !! 335 * won't have more privileges than its parent or to
319 * @minor: device file minor number, ~0 to mat !! 336 * verify if a certain access is allowed.
320 * @access: permission mask (DEVCG_ACC_READ, D !! 337 * @dev_cgroup: dev cgroup to be tested against
321 * !! 338 * @refex: new exception
322 * It is considered a complete match if an exc !! 339 * @behavior: behavior of the exception
323 * contain the entire range of provided parame <<
324 * <<
325 * Return: true in case it matches an exceptio <<
326 */ 340 */
327 static bool match_exception(struct list_head * !! 341 static bool may_access(struct dev_cgroup *dev_cgroup,
328 u32 major, u32 min !! 342 struct dev_exception_item *refex,
>> 343 enum devcg_behavior behavior)
329 { 344 {
330 struct dev_exception_item *ex; 345 struct dev_exception_item *ex;
>> 346 bool match = false;
331 347
332 list_for_each_entry_rcu(ex, exceptions !! 348 rcu_lockdep_assert(rcu_read_lock_held() ||
333 if ((type & DEVCG_DEV_BLOCK) & !! 349 lockdep_is_held(&devcgroup_mutex),
334 continue; !! 350 "device_cgroup::may_access() called without proper synchronization");
335 if ((type & DEVCG_DEV_CHAR) && <<
336 continue; <<
337 if (ex->major != ~0 && ex->maj <<
338 continue; <<
339 if (ex->minor != ~0 && ex->min <<
340 continue; <<
341 /* provided access cannot have <<
342 if (access & (~ex->access)) <<
343 continue; <<
344 return true; <<
345 } <<
346 return false; <<
347 } <<
348 <<
349 /** <<
350 * match_exception_partial - iterates the exce <<
351 * @exceptions: list of exceptions <<
352 * @type: device type (DEVCG_DEV_BLOCK or DEVC <<
353 * @major: device file major number, ~0 to mat <<
354 * @minor: device file minor number, ~0 to mat <<
355 * @access: permission mask (DEVCG_ACC_READ, D <<
356 * <<
357 * It is considered a partial match if an exce <<
358 * contain *any* of the devices specified by p <<
359 * used to make sure no extra access is being <<
360 * any of the exception list. <<
361 * <<
362 * Return: true in case the provided range mat <<
363 */ <<
364 static bool match_exception_partial(struct lis <<
365 u32 major, <<
366 { <<
367 struct dev_exception_item *ex; <<
368 351
369 list_for_each_entry_rcu(ex, exceptions !! 352 list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) {
370 lockdep_is_hel !! 353 if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK))
371 if ((type & DEVCG_DEV_BLOCK) & <<
372 continue; 354 continue;
373 if ((type & DEVCG_DEV_CHAR) && !! 355 if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR))
374 continue; 356 continue;
375 /* !! 357 if (ex->major != ~0 && ex->major != refex->major)
376 * We must be sure that both t <<
377 * range aren't masking all de <<
378 */ <<
379 if (ex->major != ~0 && major ! <<
380 continue; 358 continue;
381 if (ex->minor != ~0 && minor ! !! 359 if (ex->minor != ~0 && ex->minor != refex->minor)
382 continue; 360 continue;
383 /* !! 361 if (refex->access & (~ex->access))
384 * In order to make sure the p <<
385 * an exception, all its acces <<
386 * exception's access bits <<
387 */ <<
388 if (!(access & ex->access)) <<
389 continue; 362 continue;
390 return true; !! 363 match = true;
>> 364 break;
391 } 365 }
392 return false; <<
393 } <<
394 <<
395 /** <<
396 * verify_new_ex - verifies if a new exception <<
397 * @dev_cgroup: dev cgroup to be tested agains <<
398 * @refex: new exception <<
399 * @behavior: behavior of the exception's dev_ <<
400 * <<
401 * This is used to make sure a child cgroup wo <<
402 * than its parent <<
403 */ <<
404 static bool verify_new_ex(struct dev_cgroup *d <<
405 struct dev_exception <<
406 enum devcg_behavior <<
407 { <<
408 bool match = false; <<
409 <<
410 RCU_LOCKDEP_WARN(!rcu_read_lock_held() <<
411 !lockdep_is_held(&dev <<
412 "device_cgroup:verify <<
413 366
414 if (dev_cgroup->behavior == DEVCG_DEFA 367 if (dev_cgroup->behavior == DEVCG_DEFAULT_ALLOW) {
415 if (behavior == DEVCG_DEFAULT_ 368 if (behavior == DEVCG_DEFAULT_ALLOW) {
416 /* !! 369 /* the exception will deny access to certain devices */
417 * new exception in th <<
418 * adding extra restri <<
419 */ <<
420 return true; 370 return true;
421 } else { 371 } else {
422 /* !! 372 /* the exception will allow access to certain devices */
423 * new exception in th <<
424 * that can be accesse <<
425 * parent's exceptions <<
426 */ <<
427 match = match_exceptio <<
428 <<
429 <<
430 <<
431 <<
432 <<
433 if (match) 373 if (match)
>> 374 /*
>> 375 * a new exception allowing access shouldn't
>> 376 * match an parent's exception
>> 377 */
434 return false; 378 return false;
435 return true; 379 return true;
436 } 380 }
437 } else { 381 } else {
438 /* !! 382 /* only behavior == DEVCG_DEFAULT_DENY allowed here */
439 * Only behavior == DEVCG_DEFA <<
440 * the new exception will add <<
441 * be contained completely in <<
442 * allowed <<
443 */ <<
444 match = match_exception(&dev_c <<
445 refex- <<
446 refex- <<
447 <<
448 if (match) 383 if (match)
449 /* parent has an excep 384 /* parent has an exception that matches the proposed */
450 return true; 385 return true;
451 else 386 else
452 return false; 387 return false;
453 } 388 }
454 return false; 389 return false;
455 } 390 }
456 391
457 /* 392 /*
458 * parent_has_perm: 393 * parent_has_perm:
459 * when adding a new allow rule to a device ex 394 * when adding a new allow rule to a device exception list, the rule
460 * must be allowed in the parent device 395 * must be allowed in the parent device
461 */ 396 */
462 static int parent_has_perm(struct dev_cgroup * 397 static int parent_has_perm(struct dev_cgroup *childcg,
463 struct dev_e 398 struct dev_exception_item *ex)
464 { 399 {
465 struct dev_cgroup *parent = css_to_dev !! 400 struct cgroup *pcg = childcg->css.cgroup->parent;
>> 401 struct dev_cgroup *parent;
466 402
467 if (!parent) !! 403 if (!pcg)
468 return 1; 404 return 1;
469 return verify_new_ex(parent, ex, child !! 405 parent = cgroup_to_devcgroup(pcg);
470 } !! 406 return may_access(parent, ex, childcg->behavior);
471 <<
472 /** <<
473 * parent_allows_removal - verify if it's ok t <<
474 * @childcg: child cgroup from where the excep <<
475 * @ex: exception being removed <<
476 * <<
477 * When removing an exception in cgroups with <<
478 * be checked if removing it will give the chi <<
479 * parent. <<
480 * <<
481 * Return: true if it's ok to remove exception <<
482 */ <<
483 static bool parent_allows_removal(struct dev_c <<
484 struct dev_e <<
485 { <<
486 struct dev_cgroup *parent = css_to_dev <<
487 <<
488 if (!parent) <<
489 return true; <<
490 <<
491 /* It's always allowed to remove acces <<
492 if (childcg->behavior == DEVCG_DEFAULT <<
493 return true; <<
494 <<
495 /* <<
496 * Make sure you're not removing part <<
497 * the parent cgroup <<
498 */ <<
499 return !match_exception_partial(&paren <<
500 ex->ma <<
501 } 407 }
502 408
503 /** 409 /**
504 * may_allow_all - checks if it's possible to 410 * may_allow_all - checks if it's possible to change the behavior to
505 * allow based on parent's rul 411 * allow based on parent's rules.
506 * @parent: device cgroup's parent 412 * @parent: device cgroup's parent
507 * returns: != 0 in case it's allowed, 0 other 413 * returns: != 0 in case it's allowed, 0 otherwise
508 */ 414 */
509 static inline int may_allow_all(struct dev_cgr 415 static inline int may_allow_all(struct dev_cgroup *parent)
510 { 416 {
511 if (!parent) 417 if (!parent)
512 return 1; 418 return 1;
513 return parent->behavior == DEVCG_DEFAU 419 return parent->behavior == DEVCG_DEFAULT_ALLOW;
514 } 420 }
515 421
516 /** 422 /**
517 * revalidate_active_exceptions - walks throug 423 * revalidate_active_exceptions - walks through the active exception list and
518 * revalidates 424 * revalidates the exceptions based on parent's
519 * behavior and 425 * behavior and exceptions. The exceptions that
520 * are no longe 426 * are no longer valid will be removed.
521 * Called with 427 * Called with devcgroup_mutex held.
522 * @devcg: cgroup which exceptions will be che 428 * @devcg: cgroup which exceptions will be checked
523 * 429 *
524 * This is one of the three key functions for 430 * This is one of the three key functions for hierarchy implementation.
525 * This function is responsible for re-evaluat 431 * This function is responsible for re-evaluating all the cgroup's active
526 * exceptions due to a parent's exception chan 432 * exceptions due to a parent's exception change.
527 * Refer to Documentation/admin-guide/cgroup-v !! 433 * Refer to Documentation/cgroups/devices.txt for more details.
528 */ 434 */
529 static void revalidate_active_exceptions(struc 435 static void revalidate_active_exceptions(struct dev_cgroup *devcg)
530 { 436 {
531 struct dev_exception_item *ex; 437 struct dev_exception_item *ex;
532 struct list_head *this, *tmp; 438 struct list_head *this, *tmp;
533 439
534 list_for_each_safe(this, tmp, &devcg-> 440 list_for_each_safe(this, tmp, &devcg->exceptions) {
535 ex = container_of(this, struct 441 ex = container_of(this, struct dev_exception_item, list);
536 if (!parent_has_perm(devcg, ex 442 if (!parent_has_perm(devcg, ex))
537 dev_exception_rm(devcg 443 dev_exception_rm(devcg, ex);
538 } 444 }
539 } 445 }
540 446
541 /** 447 /**
>> 448 * get_online_devcg - walks the cgroup tree and fills a list with the online
>> 449 * groups
>> 450 * @root: cgroup used as starting point
>> 451 * @online: list that will be filled with online groups
>> 452 *
>> 453 * Must be called with devcgroup_mutex held. Grabs RCU lock.
>> 454 * Because devcgroup_mutex is held, no devcg will become online or offline
>> 455 * during the tree walk (see devcgroup_online, devcgroup_offline)
>> 456 * A separated list is needed because propagate_behavior() and
>> 457 * propagate_exception() need to allocate memory and can block.
>> 458 */
>> 459 static void get_online_devcg(struct cgroup *root, struct list_head *online)
>> 460 {
>> 461 struct cgroup *pos;
>> 462 struct dev_cgroup *devcg;
>> 463
>> 464 lockdep_assert_held(&devcgroup_mutex);
>> 465
>> 466 rcu_read_lock();
>> 467 cgroup_for_each_descendant_pre(pos, root) {
>> 468 devcg = cgroup_to_devcgroup(pos);
>> 469 if (is_devcg_online(devcg))
>> 470 list_add_tail(&devcg->propagate_pending, online);
>> 471 }
>> 472 rcu_read_unlock();
>> 473 }
>> 474
>> 475 /**
542 * propagate_exception - propagates a new exce 476 * propagate_exception - propagates a new exception to the children
543 * @devcg_root: device cgroup that added a new 477 * @devcg_root: device cgroup that added a new exception
544 * @ex: new exception to be propagated 478 * @ex: new exception to be propagated
545 * 479 *
546 * returns: 0 in case of success, != 0 in case 480 * returns: 0 in case of success, != 0 in case of error
547 */ 481 */
548 static int propagate_exception(struct dev_cgro 482 static int propagate_exception(struct dev_cgroup *devcg_root,
549 struct dev_exce 483 struct dev_exception_item *ex)
550 { 484 {
551 struct cgroup_subsys_state *pos; !! 485 struct cgroup *root = devcg_root->css.cgroup;
>> 486 struct dev_cgroup *devcg, *parent, *tmp;
552 int rc = 0; 487 int rc = 0;
>> 488 LIST_HEAD(pending);
553 489
554 rcu_read_lock(); !! 490 get_online_devcg(root, &pending);
555 <<
556 css_for_each_descendant_pre(pos, &devc <<
557 struct dev_cgroup *devcg = css <<
558 <<
559 /* <<
560 * Because devcgroup_mutex is <<
561 * online or offline during th <<
562 * methods), and online ones a <<
563 * read lock without bumping r <<
564 */ <<
565 if (pos == &devcg_root->css || <<
566 continue; <<
567 491
568 rcu_read_unlock(); !! 492 list_for_each_entry_safe(devcg, tmp, &pending, propagate_pending) {
>> 493 parent = cgroup_to_devcgroup(devcg->css.cgroup->parent);
569 494
570 /* 495 /*
571 * in case both root's behavio 496 * in case both root's behavior and devcg is allow, a new
572 * restriction means adding to 497 * restriction means adding to the exception list
573 */ 498 */
574 if (devcg_root->behavior == DE 499 if (devcg_root->behavior == DEVCG_DEFAULT_ALLOW &&
575 devcg->behavior == DEVCG_D 500 devcg->behavior == DEVCG_DEFAULT_ALLOW) {
576 rc = dev_exception_add 501 rc = dev_exception_add(devcg, ex);
577 if (rc) 502 if (rc)
578 return rc; !! 503 break;
579 } else { 504 } else {
580 /* 505 /*
581 * in the other possib 506 * in the other possible cases:
582 * root's behavior: al 507 * root's behavior: allow, devcg's: deny
583 * root's behavior: de 508 * root's behavior: deny, devcg's: deny
584 * the exception will 509 * the exception will be removed
585 */ 510 */
586 dev_exception_rm(devcg 511 dev_exception_rm(devcg, ex);
587 } 512 }
588 revalidate_active_exceptions(d 513 revalidate_active_exceptions(devcg);
589 514
590 rcu_read_lock(); !! 515 list_del_init(&devcg->propagate_pending);
591 } 516 }
592 <<
593 rcu_read_unlock(); <<
594 return rc; 517 return rc;
595 } 518 }
596 519
>> 520 static inline bool has_children(struct dev_cgroup *devcgroup)
>> 521 {
>> 522 struct cgroup *cgrp = devcgroup->css.cgroup;
>> 523
>> 524 return !list_empty(&cgrp->children);
>> 525 }
>> 526
597 /* 527 /*
598 * Modify the exception list using allow/deny 528 * Modify the exception list using allow/deny rules.
599 * CAP_SYS_ADMIN is needed for this. It's at 529 * CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD
600 * so we can give a container CAP_MKNOD to let 530 * so we can give a container CAP_MKNOD to let it create devices but not
601 * modify the exception list. 531 * modify the exception list.
602 * It seems likely we'll want to add a CAP_CON 532 * It seems likely we'll want to add a CAP_CONTAINER capability to allow
603 * us to also grant CAP_SYS_ADMIN to container 533 * us to also grant CAP_SYS_ADMIN to containers without giving away the
604 * device exception list controls, but for now 534 * device exception list controls, but for now we'll stick with CAP_SYS_ADMIN
605 * 535 *
606 * Taking rules away is always allowed (given 536 * Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting
607 * new access is only allowed if you're in the 537 * new access is only allowed if you're in the top-level cgroup, or your
608 * parent cgroup has the access you're asking 538 * parent cgroup has the access you're asking for.
609 */ 539 */
610 static int devcgroup_update_access(struct dev_ 540 static int devcgroup_update_access(struct dev_cgroup *devcgroup,
611 int filetyp !! 541 int filetype, const char *buffer)
612 { 542 {
613 const char *b; 543 const char *b;
614 char temp[12]; /* 11 + 1 char 544 char temp[12]; /* 11 + 1 characters needed for a u32 */
615 int count, rc = 0; 545 int count, rc = 0;
616 struct dev_exception_item ex; 546 struct dev_exception_item ex;
617 struct dev_cgroup *parent = css_to_dev !! 547 struct cgroup *p = devcgroup->css.cgroup;
618 struct dev_cgroup tmp_devcgrp; !! 548 struct dev_cgroup *parent = NULL;
619 549
620 if (!capable(CAP_SYS_ADMIN)) 550 if (!capable(CAP_SYS_ADMIN))
621 return -EPERM; 551 return -EPERM;
622 552
>> 553 if (p->parent)
>> 554 parent = cgroup_to_devcgroup(p->parent);
>> 555
623 memset(&ex, 0, sizeof(ex)); 556 memset(&ex, 0, sizeof(ex));
624 memset(&tmp_devcgrp, 0, sizeof(tmp_dev <<
625 b = buffer; 557 b = buffer;
626 558
627 switch (*b) { 559 switch (*b) {
628 case 'a': 560 case 'a':
629 switch (filetype) { 561 switch (filetype) {
630 case DEVCG_ALLOW: 562 case DEVCG_ALLOW:
631 if (css_has_online_chi !! 563 if (has_children(devcgroup))
632 return -EINVAL 564 return -EINVAL;
633 565
634 if (!may_allow_all(par 566 if (!may_allow_all(parent))
635 return -EPERM; 567 return -EPERM;
636 if (!parent) { !! 568 dev_exception_clean(devcgroup);
637 devcgroup->beh !! 569 devcgroup->behavior = DEVCG_DEFAULT_ALLOW;
638 dev_exception_ !! 570 if (!parent)
639 break; 571 break;
640 } <<
641 572
642 INIT_LIST_HEAD(&tmp_de <<
643 rc = dev_exceptions_co <<
644 <<
645 if (rc) <<
646 return rc; <<
647 dev_exception_clean(de <<
648 rc = dev_exceptions_co 573 rc = dev_exceptions_copy(&devcgroup->exceptions,
649 574 &parent->exceptions);
650 if (rc) { !! 575 if (rc)
651 dev_exceptions <<
652 <<
653 return rc; 576 return rc;
654 } <<
655 devcgroup->behavior = <<
656 dev_exception_clean(&t <<
657 break; 577 break;
658 case DEVCG_DENY: 578 case DEVCG_DENY:
659 if (css_has_online_chi !! 579 if (has_children(devcgroup))
660 return -EINVAL 580 return -EINVAL;
661 581
662 dev_exception_clean(de 582 dev_exception_clean(devcgroup);
663 devcgroup->behavior = 583 devcgroup->behavior = DEVCG_DEFAULT_DENY;
664 break; 584 break;
665 default: 585 default:
666 return -EINVAL; 586 return -EINVAL;
667 } 587 }
668 return 0; 588 return 0;
669 case 'b': 589 case 'b':
670 ex.type = DEVCG_DEV_BLOCK; !! 590 ex.type = DEV_BLOCK;
671 break; 591 break;
672 case 'c': 592 case 'c':
673 ex.type = DEVCG_DEV_CHAR; !! 593 ex.type = DEV_CHAR;
674 break; 594 break;
675 default: 595 default:
676 return -EINVAL; 596 return -EINVAL;
677 } 597 }
678 b++; 598 b++;
679 if (!isspace(*b)) 599 if (!isspace(*b))
680 return -EINVAL; 600 return -EINVAL;
681 b++; 601 b++;
682 if (*b == '*') { 602 if (*b == '*') {
683 ex.major = ~0; 603 ex.major = ~0;
684 b++; 604 b++;
685 } else if (isdigit(*b)) { 605 } else if (isdigit(*b)) {
686 memset(temp, 0, sizeof(temp)); 606 memset(temp, 0, sizeof(temp));
687 for (count = 0; count < sizeof 607 for (count = 0; count < sizeof(temp) - 1; count++) {
688 temp[count] = *b; 608 temp[count] = *b;
689 b++; 609 b++;
690 if (!isdigit(*b)) 610 if (!isdigit(*b))
691 break; 611 break;
692 } 612 }
693 rc = kstrtou32(temp, 10, &ex.m 613 rc = kstrtou32(temp, 10, &ex.major);
694 if (rc) 614 if (rc)
695 return -EINVAL; 615 return -EINVAL;
696 } else { 616 } else {
697 return -EINVAL; 617 return -EINVAL;
698 } 618 }
699 if (*b != ':') 619 if (*b != ':')
700 return -EINVAL; 620 return -EINVAL;
701 b++; 621 b++;
702 622
703 /* read minor */ 623 /* read minor */
704 if (*b == '*') { 624 if (*b == '*') {
705 ex.minor = ~0; 625 ex.minor = ~0;
706 b++; 626 b++;
707 } else if (isdigit(*b)) { 627 } else if (isdigit(*b)) {
708 memset(temp, 0, sizeof(temp)); 628 memset(temp, 0, sizeof(temp));
709 for (count = 0; count < sizeof 629 for (count = 0; count < sizeof(temp) - 1; count++) {
710 temp[count] = *b; 630 temp[count] = *b;
711 b++; 631 b++;
712 if (!isdigit(*b)) 632 if (!isdigit(*b))
713 break; 633 break;
714 } 634 }
715 rc = kstrtou32(temp, 10, &ex.m 635 rc = kstrtou32(temp, 10, &ex.minor);
716 if (rc) 636 if (rc)
717 return -EINVAL; 637 return -EINVAL;
718 } else { 638 } else {
719 return -EINVAL; 639 return -EINVAL;
720 } 640 }
721 if (!isspace(*b)) 641 if (!isspace(*b))
722 return -EINVAL; 642 return -EINVAL;
723 for (b++, count = 0; count < 3; count+ 643 for (b++, count = 0; count < 3; count++, b++) {
724 switch (*b) { 644 switch (*b) {
725 case 'r': 645 case 'r':
726 ex.access |= DEVCG_ACC !! 646 ex.access |= ACC_READ;
727 break; 647 break;
728 case 'w': 648 case 'w':
729 ex.access |= DEVCG_ACC !! 649 ex.access |= ACC_WRITE;
730 break; 650 break;
731 case 'm': 651 case 'm':
732 ex.access |= DEVCG_ACC !! 652 ex.access |= ACC_MKNOD;
733 break; 653 break;
734 case '\n': 654 case '\n':
735 case '\0': 655 case '\0':
736 count = 3; 656 count = 3;
737 break; 657 break;
738 default: 658 default:
739 return -EINVAL; 659 return -EINVAL;
740 } 660 }
741 } 661 }
742 662
743 switch (filetype) { 663 switch (filetype) {
744 case DEVCG_ALLOW: 664 case DEVCG_ALLOW:
>> 665 if (!parent_has_perm(devcgroup, &ex))
>> 666 return -EPERM;
745 /* 667 /*
746 * If the default policy is to 668 * If the default policy is to allow by default, try to remove
747 * an matching exception inste 669 * an matching exception instead. And be silent about it: we
748 * don't want to break compati 670 * don't want to break compatibility
749 */ 671 */
750 if (devcgroup->behavior == DEV 672 if (devcgroup->behavior == DEVCG_DEFAULT_ALLOW) {
751 /* Check if the parent <<
752 if (!parent_allows_rem <<
753 return -EPERM; <<
754 dev_exception_rm(devcg 673 dev_exception_rm(devcgroup, &ex);
755 break; !! 674 return 0;
756 } 675 }
757 <<
758 if (!parent_has_perm(devcgroup <<
759 return -EPERM; <<
760 rc = dev_exception_add(devcgro 676 rc = dev_exception_add(devcgroup, &ex);
761 break; 677 break;
762 case DEVCG_DENY: 678 case DEVCG_DENY:
763 /* 679 /*
764 * If the default policy is to 680 * If the default policy is to deny by default, try to remove
765 * an matching exception inste 681 * an matching exception instead. And be silent about it: we
766 * don't want to break compati 682 * don't want to break compatibility
767 */ 683 */
768 if (devcgroup->behavior == DEV 684 if (devcgroup->behavior == DEVCG_DEFAULT_DENY)
769 dev_exception_rm(devcg 685 dev_exception_rm(devcgroup, &ex);
770 else 686 else
771 rc = dev_exception_add 687 rc = dev_exception_add(devcgroup, &ex);
772 688
773 if (rc) 689 if (rc)
774 break; 690 break;
775 /* we only propagate new restr 691 /* we only propagate new restrictions */
776 rc = propagate_exception(devcg 692 rc = propagate_exception(devcgroup, &ex);
777 break; 693 break;
778 default: 694 default:
779 rc = -EINVAL; 695 rc = -EINVAL;
780 } 696 }
781 return rc; 697 return rc;
782 } 698 }
783 699
784 static ssize_t devcgroup_access_write(struct k !! 700 static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft,
785 char *bu !! 701 const char *buffer)
786 { 702 {
787 int retval; 703 int retval;
788 704
789 mutex_lock(&devcgroup_mutex); 705 mutex_lock(&devcgroup_mutex);
790 retval = devcgroup_update_access(css_t !! 706 retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp),
791 of_cf !! 707 cft->private, buffer);
792 mutex_unlock(&devcgroup_mutex); 708 mutex_unlock(&devcgroup_mutex);
793 return retval ?: nbytes; !! 709 return retval;
794 } 710 }
795 711
796 static struct cftype dev_cgroup_files[] = { 712 static struct cftype dev_cgroup_files[] = {
797 { 713 {
798 .name = "allow", 714 .name = "allow",
799 .write = devcgroup_access_writ !! 715 .write_string = devcgroup_access_write,
800 .private = DEVCG_ALLOW, 716 .private = DEVCG_ALLOW,
801 }, 717 },
802 { 718 {
803 .name = "deny", 719 .name = "deny",
804 .write = devcgroup_access_writ !! 720 .write_string = devcgroup_access_write,
805 .private = DEVCG_DENY, 721 .private = DEVCG_DENY,
806 }, 722 },
807 { 723 {
808 .name = "list", 724 .name = "list",
809 .seq_show = devcgroup_seq_show !! 725 .read_seq_string = devcgroup_seq_read,
810 .private = DEVCG_LIST, 726 .private = DEVCG_LIST,
811 }, 727 },
812 { } /* terminate */ 728 { } /* terminate */
813 }; 729 };
814 730
815 struct cgroup_subsys devices_cgrp_subsys = { !! 731 struct cgroup_subsys devices_subsys = {
>> 732 .name = "devices",
>> 733 .can_attach = devcgroup_can_attach,
816 .css_alloc = devcgroup_css_alloc, 734 .css_alloc = devcgroup_css_alloc,
817 .css_free = devcgroup_css_free, 735 .css_free = devcgroup_css_free,
818 .css_online = devcgroup_online, 736 .css_online = devcgroup_online,
819 .css_offline = devcgroup_offline, 737 .css_offline = devcgroup_offline,
820 .legacy_cftypes = dev_cgroup_files, !! 738 .subsys_id = devices_subsys_id,
>> 739 .base_cftypes = dev_cgroup_files,
821 }; 740 };
822 741
823 /** 742 /**
824 * devcgroup_legacy_check_permission - checks !! 743 * __devcgroup_check_permission - checks if an inode operation is permitted
>> 744 * @dev_cgroup: the dev cgroup to be tested against
825 * @type: device type 745 * @type: device type
826 * @major: device major number 746 * @major: device major number
827 * @minor: device minor number 747 * @minor: device minor number
828 * @access: combination of DEVCG_ACC_WRITE, DE !! 748 * @access: combination of ACC_WRITE, ACC_READ and ACC_MKNOD
829 * 749 *
830 * returns 0 on success, -EPERM case the opera 750 * returns 0 on success, -EPERM case the operation is not permitted
831 */ 751 */
832 static int devcgroup_legacy_check_permission(s !! 752 static int __devcgroup_check_permission(short type, u32 major, u32 minor,
833 short !! 753 short access)
834 { 754 {
835 struct dev_cgroup *dev_cgroup; 755 struct dev_cgroup *dev_cgroup;
836 bool rc; !! 756 struct dev_exception_item ex;
>> 757 int rc;
>> 758
>> 759 memset(&ex, 0, sizeof(ex));
>> 760 ex.type = type;
>> 761 ex.major = major;
>> 762 ex.minor = minor;
>> 763 ex.access = access;
837 764
838 rcu_read_lock(); 765 rcu_read_lock();
839 dev_cgroup = task_devcgroup(current); 766 dev_cgroup = task_devcgroup(current);
840 if (dev_cgroup->behavior == DEVCG_DEFA !! 767 rc = may_access(dev_cgroup, &ex, dev_cgroup->behavior);
841 /* Can't match any of the exce <<
842 rc = !match_exception_partial( <<
843 <<
844 else <<
845 /* Need to match completely on <<
846 rc = match_exception(&dev_cgro <<
847 minor, ac <<
848 rcu_read_unlock(); 768 rcu_read_unlock();
849 769
850 if (!rc) 770 if (!rc)
851 return -EPERM; 771 return -EPERM;
852 772
853 return 0; 773 return 0;
854 } 774 }
855 775
856 #endif /* CONFIG_CGROUP_DEVICE */ !! 776 int __devcgroup_inode_permission(struct inode *inode, int mask)
>> 777 {
>> 778 short type, access = 0;
>> 779
>> 780 if (S_ISBLK(inode->i_mode))
>> 781 type = DEV_BLOCK;
>> 782 if (S_ISCHR(inode->i_mode))
>> 783 type = DEV_CHAR;
>> 784 if (mask & MAY_WRITE)
>> 785 access |= ACC_WRITE;
>> 786 if (mask & MAY_READ)
>> 787 access |= ACC_READ;
857 788
858 #if defined(CONFIG_CGROUP_DEVICE) || defined(C !! 789 return __devcgroup_check_permission(type, imajor(inode), iminor(inode),
>> 790 access);
>> 791 }
859 792
860 int devcgroup_check_permission(short type, u32 !! 793 int devcgroup_inode_mknod(int mode, dev_t dev)
861 { 794 {
862 int rc = BPF_CGROUP_RUN_PROG_DEVICE_CG !! 795 short type;
863 796
864 if (rc) !! 797 if (!S_ISBLK(mode) && !S_ISCHR(mode))
865 return rc; !! 798 return 0;
866 799
867 #ifdef CONFIG_CGROUP_DEVICE !! 800 if (S_ISBLK(mode))
868 return devcgroup_legacy_check_permissi !! 801 type = DEV_BLOCK;
>> 802 else
>> 803 type = DEV_CHAR;
869 804
870 #else /* CONFIG_CGROUP_DEVICE */ !! 805 return __devcgroup_check_permission(type, MAJOR(dev), MINOR(dev),
871 return 0; !! 806 ACC_MKNOD);
872 807
873 #endif /* CONFIG_CGROUP_DEVICE */ <<
874 } 808 }
875 EXPORT_SYMBOL(devcgroup_check_permission); <<
876 #endif /* defined(CONFIG_CGROUP_DEVICE) || def <<
877 809
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