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