1 // SPDX-License-Identifier: GPL-2.0 1 // SPDX-License-Identifier: GPL-2.0
2 /* 2 /*
3 * device_cgroup.c - device cgroup subsystem 3 * device_cgroup.c - device cgroup subsystem
4 * 4 *
5 * Copyright 2007 IBM Corp 5 * Copyright 2007 IBM Corp
6 */ 6 */
7 7
8 #include <linux/bpf-cgroup.h> <<
9 #include <linux/device_cgroup.h> 8 #include <linux/device_cgroup.h>
10 #include <linux/cgroup.h> 9 #include <linux/cgroup.h>
11 #include <linux/ctype.h> 10 #include <linux/ctype.h>
12 #include <linux/list.h> 11 #include <linux/list.h>
13 #include <linux/uaccess.h> 12 #include <linux/uaccess.h>
14 #include <linux/seq_file.h> 13 #include <linux/seq_file.h>
15 #include <linux/slab.h> 14 #include <linux/slab.h>
16 #include <linux/rcupdate.h> 15 #include <linux/rcupdate.h>
17 #include <linux/mutex.h> 16 #include <linux/mutex.h>
18 17
19 #ifdef CONFIG_CGROUP_DEVICE 18 #ifdef CONFIG_CGROUP_DEVICE
20 19
21 static DEFINE_MUTEX(devcgroup_mutex); 20 static DEFINE_MUTEX(devcgroup_mutex);
22 21
23 enum devcg_behavior { 22 enum devcg_behavior {
24 DEVCG_DEFAULT_NONE, 23 DEVCG_DEFAULT_NONE,
25 DEVCG_DEFAULT_ALLOW, 24 DEVCG_DEFAULT_ALLOW,
26 DEVCG_DEFAULT_DENY, 25 DEVCG_DEFAULT_DENY,
27 }; 26 };
28 27
29 /* 28 /*
30 * exception list locking rules: 29 * exception list locking rules:
31 * hold devcgroup_mutex for update/read. 30 * hold devcgroup_mutex for update/read.
32 * hold rcu_read_lock() for read. 31 * hold rcu_read_lock() for read.
33 */ 32 */
34 33
35 struct dev_exception_item { 34 struct dev_exception_item {
36 u32 major, minor; 35 u32 major, minor;
37 short type; 36 short type;
38 short access; 37 short access;
39 struct list_head list; 38 struct list_head list;
40 struct rcu_head rcu; 39 struct rcu_head rcu;
41 }; 40 };
42 41
43 struct dev_cgroup { 42 struct dev_cgroup {
44 struct cgroup_subsys_state css; 43 struct cgroup_subsys_state css;
45 struct list_head exceptions; 44 struct list_head exceptions;
46 enum devcg_behavior behavior; 45 enum devcg_behavior behavior;
47 }; 46 };
48 47
49 static inline struct dev_cgroup *css_to_devcgr 48 static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s)
50 { 49 {
51 return s ? container_of(s, struct dev_ 50 return s ? container_of(s, struct dev_cgroup, css) : NULL;
52 } 51 }
53 52
54 static inline struct dev_cgroup *task_devcgrou 53 static inline struct dev_cgroup *task_devcgroup(struct task_struct *task)
55 { 54 {
56 return css_to_devcgroup(task_css(task, 55 return css_to_devcgroup(task_css(task, devices_cgrp_id));
57 } 56 }
58 57
59 /* 58 /*
60 * called under devcgroup_mutex 59 * called under devcgroup_mutex
61 */ 60 */
62 static int dev_exceptions_copy(struct list_hea 61 static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig)
63 { 62 {
64 struct dev_exception_item *ex, *tmp, * 63 struct dev_exception_item *ex, *tmp, *new;
65 64
66 lockdep_assert_held(&devcgroup_mutex); 65 lockdep_assert_held(&devcgroup_mutex);
67 66
68 list_for_each_entry(ex, orig, list) { 67 list_for_each_entry(ex, orig, list) {
69 new = kmemdup(ex, sizeof(*ex), 68 new = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
70 if (!new) 69 if (!new)
71 goto free_and_exit; 70 goto free_and_exit;
72 list_add_tail(&new->list, dest 71 list_add_tail(&new->list, dest);
73 } 72 }
74 73
75 return 0; 74 return 0;
76 75
77 free_and_exit: 76 free_and_exit:
78 list_for_each_entry_safe(ex, tmp, dest 77 list_for_each_entry_safe(ex, tmp, dest, list) {
79 list_del(&ex->list); 78 list_del(&ex->list);
80 kfree(ex); 79 kfree(ex);
81 } 80 }
82 return -ENOMEM; 81 return -ENOMEM;
83 } 82 }
84 83
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 /* 84 /*
97 * called under devcgroup_mutex 85 * called under devcgroup_mutex
98 */ 86 */
99 static int dev_exception_add(struct dev_cgroup 87 static int dev_exception_add(struct dev_cgroup *dev_cgroup,
100 struct dev_except 88 struct dev_exception_item *ex)
101 { 89 {
102 struct dev_exception_item *excopy, *wa 90 struct dev_exception_item *excopy, *walk;
103 91
104 lockdep_assert_held(&devcgroup_mutex); 92 lockdep_assert_held(&devcgroup_mutex);
105 93
106 excopy = kmemdup(ex, sizeof(*ex), GFP_ 94 excopy = kmemdup(ex, sizeof(*ex), GFP_KERNEL);
107 if (!excopy) 95 if (!excopy)
108 return -ENOMEM; 96 return -ENOMEM;
109 97
110 list_for_each_entry(walk, &dev_cgroup- 98 list_for_each_entry(walk, &dev_cgroup->exceptions, list) {
111 if (walk->type != ex->type) 99 if (walk->type != ex->type)
112 continue; 100 continue;
113 if (walk->major != ex->major) 101 if (walk->major != ex->major)
114 continue; 102 continue;
115 if (walk->minor != ex->minor) 103 if (walk->minor != ex->minor)
116 continue; 104 continue;
117 105
118 walk->access |= ex->access; 106 walk->access |= ex->access;
119 kfree(excopy); 107 kfree(excopy);
120 excopy = NULL; 108 excopy = NULL;
121 } 109 }
122 110
123 if (excopy != NULL) 111 if (excopy != NULL)
124 list_add_tail_rcu(&excopy->lis 112 list_add_tail_rcu(&excopy->list, &dev_cgroup->exceptions);
125 return 0; 113 return 0;
126 } 114 }
127 115
128 /* 116 /*
129 * called under devcgroup_mutex 117 * called under devcgroup_mutex
130 */ 118 */
131 static void dev_exception_rm(struct dev_cgroup 119 static void dev_exception_rm(struct dev_cgroup *dev_cgroup,
132 struct dev_except 120 struct dev_exception_item *ex)
133 { 121 {
134 struct dev_exception_item *walk, *tmp; 122 struct dev_exception_item *walk, *tmp;
135 123
136 lockdep_assert_held(&devcgroup_mutex); 124 lockdep_assert_held(&devcgroup_mutex);
137 125
138 list_for_each_entry_safe(walk, tmp, &d 126 list_for_each_entry_safe(walk, tmp, &dev_cgroup->exceptions, list) {
139 if (walk->type != ex->type) 127 if (walk->type != ex->type)
140 continue; 128 continue;
141 if (walk->major != ex->major) 129 if (walk->major != ex->major)
142 continue; 130 continue;
143 if (walk->minor != ex->minor) 131 if (walk->minor != ex->minor)
144 continue; 132 continue;
145 133
146 walk->access &= ~ex->access; 134 walk->access &= ~ex->access;
147 if (!walk->access) { 135 if (!walk->access) {
148 list_del_rcu(&walk->li 136 list_del_rcu(&walk->list);
149 kfree_rcu(walk, rcu); 137 kfree_rcu(walk, rcu);
150 } 138 }
151 } 139 }
152 } 140 }
153 141
154 static void __dev_exception_clean(struct dev_c 142 static void __dev_exception_clean(struct dev_cgroup *dev_cgroup)
155 { 143 {
156 struct dev_exception_item *ex, *tmp; 144 struct dev_exception_item *ex, *tmp;
157 145
158 list_for_each_entry_safe(ex, tmp, &dev 146 list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) {
159 list_del_rcu(&ex->list); 147 list_del_rcu(&ex->list);
160 kfree_rcu(ex, rcu); 148 kfree_rcu(ex, rcu);
161 } 149 }
162 } 150 }
163 151
164 /** 152 /**
165 * dev_exception_clean - frees all entries of 153 * dev_exception_clean - frees all entries of the exception list
166 * @dev_cgroup: dev_cgroup with the exception 154 * @dev_cgroup: dev_cgroup with the exception list to be cleaned
167 * 155 *
168 * called under devcgroup_mutex 156 * called under devcgroup_mutex
169 */ 157 */
170 static void dev_exception_clean(struct dev_cgr 158 static void dev_exception_clean(struct dev_cgroup *dev_cgroup)
171 { 159 {
172 lockdep_assert_held(&devcgroup_mutex); 160 lockdep_assert_held(&devcgroup_mutex);
173 161
174 __dev_exception_clean(dev_cgroup); 162 __dev_exception_clean(dev_cgroup);
175 } 163 }
176 164
177 static inline bool is_devcg_online(const struc 165 static inline bool is_devcg_online(const struct dev_cgroup *devcg)
178 { 166 {
179 return (devcg->behavior != DEVCG_DEFAU 167 return (devcg->behavior != DEVCG_DEFAULT_NONE);
180 } 168 }
181 169
182 /** 170 /**
183 * devcgroup_online - initializes devcgroup's 171 * devcgroup_online - initializes devcgroup's behavior and exceptions based on
184 * parent's 172 * parent's
185 * @css: css getting online 173 * @css: css getting online
186 * returns 0 in case of success, error code ot 174 * returns 0 in case of success, error code otherwise
187 */ 175 */
188 static int devcgroup_online(struct cgroup_subs 176 static int devcgroup_online(struct cgroup_subsys_state *css)
189 { 177 {
190 struct dev_cgroup *dev_cgroup = css_to 178 struct dev_cgroup *dev_cgroup = css_to_devcgroup(css);
191 struct dev_cgroup *parent_dev_cgroup = 179 struct dev_cgroup *parent_dev_cgroup = css_to_devcgroup(css->parent);
192 int ret = 0; 180 int ret = 0;
193 181
194 mutex_lock(&devcgroup_mutex); 182 mutex_lock(&devcgroup_mutex);
195 183
196 if (parent_dev_cgroup == NULL) 184 if (parent_dev_cgroup == NULL)
197 dev_cgroup->behavior = DEVCG_D 185 dev_cgroup->behavior = DEVCG_DEFAULT_ALLOW;
198 else { 186 else {
199 ret = dev_exceptions_copy(&dev 187 ret = dev_exceptions_copy(&dev_cgroup->exceptions,
200 &par 188 &parent_dev_cgroup->exceptions);
201 if (!ret) 189 if (!ret)
202 dev_cgroup->behavior = 190 dev_cgroup->behavior = parent_dev_cgroup->behavior;
203 } 191 }
204 mutex_unlock(&devcgroup_mutex); 192 mutex_unlock(&devcgroup_mutex);
205 193
206 return ret; 194 return ret;
207 } 195 }
208 196
209 static void devcgroup_offline(struct cgroup_su 197 static void devcgroup_offline(struct cgroup_subsys_state *css)
210 { 198 {
211 struct dev_cgroup *dev_cgroup = css_to 199 struct dev_cgroup *dev_cgroup = css_to_devcgroup(css);
212 200
213 mutex_lock(&devcgroup_mutex); 201 mutex_lock(&devcgroup_mutex);
214 dev_cgroup->behavior = DEVCG_DEFAULT_N 202 dev_cgroup->behavior = DEVCG_DEFAULT_NONE;
215 mutex_unlock(&devcgroup_mutex); 203 mutex_unlock(&devcgroup_mutex);
216 } 204 }
217 205
218 /* 206 /*
219 * called from kernel/cgroup/cgroup.c with cgr !! 207 * called from kernel/cgroup.c with cgroup_lock() held.
220 */ 208 */
221 static struct cgroup_subsys_state * 209 static struct cgroup_subsys_state *
222 devcgroup_css_alloc(struct cgroup_subsys_state 210 devcgroup_css_alloc(struct cgroup_subsys_state *parent_css)
223 { 211 {
224 struct dev_cgroup *dev_cgroup; 212 struct dev_cgroup *dev_cgroup;
225 213
226 dev_cgroup = kzalloc(sizeof(*dev_cgrou 214 dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL);
227 if (!dev_cgroup) 215 if (!dev_cgroup)
228 return ERR_PTR(-ENOMEM); 216 return ERR_PTR(-ENOMEM);
229 INIT_LIST_HEAD(&dev_cgroup->exceptions 217 INIT_LIST_HEAD(&dev_cgroup->exceptions);
230 dev_cgroup->behavior = DEVCG_DEFAULT_N 218 dev_cgroup->behavior = DEVCG_DEFAULT_NONE;
231 219
232 return &dev_cgroup->css; 220 return &dev_cgroup->css;
233 } 221 }
234 222
235 static void devcgroup_css_free(struct cgroup_s 223 static void devcgroup_css_free(struct cgroup_subsys_state *css)
236 { 224 {
237 struct dev_cgroup *dev_cgroup = css_to 225 struct dev_cgroup *dev_cgroup = css_to_devcgroup(css);
238 226
239 __dev_exception_clean(dev_cgroup); 227 __dev_exception_clean(dev_cgroup);
240 kfree(dev_cgroup); 228 kfree(dev_cgroup);
241 } 229 }
242 230
243 #define DEVCG_ALLOW 1 231 #define DEVCG_ALLOW 1
244 #define DEVCG_DENY 2 232 #define DEVCG_DENY 2
245 #define DEVCG_LIST 3 233 #define DEVCG_LIST 3
246 234
247 #define MAJMINLEN 13 235 #define MAJMINLEN 13
248 #define ACCLEN 4 236 #define ACCLEN 4
249 237
250 static void set_access(char *acc, short access 238 static void set_access(char *acc, short access)
251 { 239 {
252 int idx = 0; 240 int idx = 0;
253 memset(acc, 0, ACCLEN); 241 memset(acc, 0, ACCLEN);
254 if (access & DEVCG_ACC_READ) 242 if (access & DEVCG_ACC_READ)
255 acc[idx++] = 'r'; 243 acc[idx++] = 'r';
256 if (access & DEVCG_ACC_WRITE) 244 if (access & DEVCG_ACC_WRITE)
257 acc[idx++] = 'w'; 245 acc[idx++] = 'w';
258 if (access & DEVCG_ACC_MKNOD) 246 if (access & DEVCG_ACC_MKNOD)
259 acc[idx++] = 'm'; 247 acc[idx++] = 'm';
260 } 248 }
261 249
262 static char type_to_char(short type) 250 static char type_to_char(short type)
263 { 251 {
264 if (type == DEVCG_DEV_ALL) 252 if (type == DEVCG_DEV_ALL)
265 return 'a'; 253 return 'a';
266 if (type == DEVCG_DEV_CHAR) 254 if (type == DEVCG_DEV_CHAR)
267 return 'c'; 255 return 'c';
268 if (type == DEVCG_DEV_BLOCK) 256 if (type == DEVCG_DEV_BLOCK)
269 return 'b'; 257 return 'b';
270 return 'X'; 258 return 'X';
271 } 259 }
272 260
273 static void set_majmin(char *str, unsigned m) 261 static void set_majmin(char *str, unsigned m)
274 { 262 {
275 if (m == ~0) 263 if (m == ~0)
276 strcpy(str, "*"); 264 strcpy(str, "*");
277 else 265 else
278 sprintf(str, "%u", m); 266 sprintf(str, "%u", m);
279 } 267 }
280 268
281 static int devcgroup_seq_show(struct seq_file 269 static int devcgroup_seq_show(struct seq_file *m, void *v)
282 { 270 {
283 struct dev_cgroup *devcgroup = css_to_ 271 struct dev_cgroup *devcgroup = css_to_devcgroup(seq_css(m));
284 struct dev_exception_item *ex; 272 struct dev_exception_item *ex;
285 char maj[MAJMINLEN], min[MAJMINLEN], a 273 char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN];
286 274
287 rcu_read_lock(); 275 rcu_read_lock();
288 /* 276 /*
289 * To preserve the compatibility: 277 * To preserve the compatibility:
290 * - Only show the "all devices" when 278 * - Only show the "all devices" when the default policy is to allow
291 * - List the exceptions in case the d 279 * - List the exceptions in case the default policy is to deny
292 * This way, the file remains as a "wh 280 * This way, the file remains as a "whitelist of devices"
293 */ 281 */
294 if (devcgroup->behavior == DEVCG_DEFAU 282 if (devcgroup->behavior == DEVCG_DEFAULT_ALLOW) {
295 set_access(acc, DEVCG_ACC_MASK 283 set_access(acc, DEVCG_ACC_MASK);
296 set_majmin(maj, ~0); 284 set_majmin(maj, ~0);
297 set_majmin(min, ~0); 285 set_majmin(min, ~0);
298 seq_printf(m, "%c %s:%s %s\n", 286 seq_printf(m, "%c %s:%s %s\n", type_to_char(DEVCG_DEV_ALL),
299 maj, min, acc); 287 maj, min, acc);
300 } else { 288 } else {
301 list_for_each_entry_rcu(ex, &d 289 list_for_each_entry_rcu(ex, &devcgroup->exceptions, list) {
302 set_access(acc, ex->ac 290 set_access(acc, ex->access);
303 set_majmin(maj, ex->ma 291 set_majmin(maj, ex->major);
304 set_majmin(min, ex->mi 292 set_majmin(min, ex->minor);
305 seq_printf(m, "%c %s:% 293 seq_printf(m, "%c %s:%s %s\n", type_to_char(ex->type),
306 maj, min, a 294 maj, min, acc);
307 } 295 }
308 } 296 }
309 rcu_read_unlock(); 297 rcu_read_unlock();
310 298
311 return 0; 299 return 0;
312 } 300 }
313 301
314 /** 302 /**
315 * match_exception - iterates the excepti 303 * match_exception - iterates the exception list trying to find a complete match
316 * @exceptions: list of exceptions 304 * @exceptions: list of exceptions
317 * @type: device type (DEVCG_DEV_BLOCK or DEVC 305 * @type: device type (DEVCG_DEV_BLOCK or DEVCG_DEV_CHAR)
318 * @major: device file major number, ~0 to mat 306 * @major: device file major number, ~0 to match all
319 * @minor: device file minor number, ~0 to mat 307 * @minor: device file minor number, ~0 to match all
320 * @access: permission mask (DEVCG_ACC_READ, D 308 * @access: permission mask (DEVCG_ACC_READ, DEVCG_ACC_WRITE, DEVCG_ACC_MKNOD)
321 * 309 *
322 * It is considered a complete match if an exc 310 * It is considered a complete match if an exception is found that will
323 * contain the entire range of provided parame 311 * contain the entire range of provided parameters.
324 * 312 *
325 * Return: true in case it matches an exceptio 313 * Return: true in case it matches an exception completely
326 */ 314 */
327 static bool match_exception(struct list_head * 315 static bool match_exception(struct list_head *exceptions, short type,
328 u32 major, u32 min 316 u32 major, u32 minor, short access)
329 { 317 {
330 struct dev_exception_item *ex; 318 struct dev_exception_item *ex;
331 319
332 list_for_each_entry_rcu(ex, exceptions 320 list_for_each_entry_rcu(ex, exceptions, list) {
333 if ((type & DEVCG_DEV_BLOCK) & 321 if ((type & DEVCG_DEV_BLOCK) && !(ex->type & DEVCG_DEV_BLOCK))
334 continue; 322 continue;
335 if ((type & DEVCG_DEV_CHAR) && 323 if ((type & DEVCG_DEV_CHAR) && !(ex->type & DEVCG_DEV_CHAR))
336 continue; 324 continue;
337 if (ex->major != ~0 && ex->maj 325 if (ex->major != ~0 && ex->major != major)
338 continue; 326 continue;
339 if (ex->minor != ~0 && ex->min 327 if (ex->minor != ~0 && ex->minor != minor)
340 continue; 328 continue;
341 /* provided access cannot have 329 /* provided access cannot have more than the exception rule */
342 if (access & (~ex->access)) 330 if (access & (~ex->access))
343 continue; 331 continue;
344 return true; 332 return true;
345 } 333 }
346 return false; 334 return false;
347 } 335 }
348 336
349 /** 337 /**
350 * match_exception_partial - iterates the exce 338 * match_exception_partial - iterates the exception list trying to find a partial match
351 * @exceptions: list of exceptions 339 * @exceptions: list of exceptions
352 * @type: device type (DEVCG_DEV_BLOCK or DEVC 340 * @type: device type (DEVCG_DEV_BLOCK or DEVCG_DEV_CHAR)
353 * @major: device file major number, ~0 to mat 341 * @major: device file major number, ~0 to match all
354 * @minor: device file minor number, ~0 to mat 342 * @minor: device file minor number, ~0 to match all
355 * @access: permission mask (DEVCG_ACC_READ, D 343 * @access: permission mask (DEVCG_ACC_READ, DEVCG_ACC_WRITE, DEVCG_ACC_MKNOD)
356 * 344 *
357 * It is considered a partial match if an exce 345 * It is considered a partial match if an exception's range is found to
358 * contain *any* of the devices specified by p 346 * contain *any* of the devices specified by provided parameters. This is
359 * used to make sure no extra access is being 347 * used to make sure no extra access is being granted that is forbidden by
360 * any of the exception list. 348 * any of the exception list.
361 * 349 *
362 * Return: true in case the provided range mat 350 * Return: true in case the provided range mat matches an exception completely
363 */ 351 */
364 static bool match_exception_partial(struct lis 352 static bool match_exception_partial(struct list_head *exceptions, short type,
365 u32 major, 353 u32 major, u32 minor, short access)
366 { 354 {
367 struct dev_exception_item *ex; 355 struct dev_exception_item *ex;
368 356
369 list_for_each_entry_rcu(ex, exceptions 357 list_for_each_entry_rcu(ex, exceptions, list,
370 lockdep_is_hel 358 lockdep_is_held(&devcgroup_mutex)) {
371 if ((type & DEVCG_DEV_BLOCK) & 359 if ((type & DEVCG_DEV_BLOCK) && !(ex->type & DEVCG_DEV_BLOCK))
372 continue; 360 continue;
373 if ((type & DEVCG_DEV_CHAR) && 361 if ((type & DEVCG_DEV_CHAR) && !(ex->type & DEVCG_DEV_CHAR))
374 continue; 362 continue;
375 /* 363 /*
376 * We must be sure that both t 364 * We must be sure that both the exception and the provided
377 * range aren't masking all de 365 * range aren't masking all devices
378 */ 366 */
379 if (ex->major != ~0 && major ! 367 if (ex->major != ~0 && major != ~0 && ex->major != major)
380 continue; 368 continue;
381 if (ex->minor != ~0 && minor ! 369 if (ex->minor != ~0 && minor != ~0 && ex->minor != minor)
382 continue; 370 continue;
383 /* 371 /*
384 * In order to make sure the p 372 * In order to make sure the provided range isn't matching
385 * an exception, all its acces 373 * an exception, all its access bits shouldn't match the
386 * exception's access bits 374 * exception's access bits
387 */ 375 */
388 if (!(access & ex->access)) 376 if (!(access & ex->access))
389 continue; 377 continue;
390 return true; 378 return true;
391 } 379 }
392 return false; 380 return false;
393 } 381 }
394 382
395 /** 383 /**
396 * verify_new_ex - verifies if a new exception 384 * verify_new_ex - verifies if a new exception is allowed by parent cgroup's permissions
397 * @dev_cgroup: dev cgroup to be tested agains 385 * @dev_cgroup: dev cgroup to be tested against
398 * @refex: new exception 386 * @refex: new exception
399 * @behavior: behavior of the exception's dev_ 387 * @behavior: behavior of the exception's dev_cgroup
400 * 388 *
401 * This is used to make sure a child cgroup wo 389 * This is used to make sure a child cgroup won't have more privileges
402 * than its parent 390 * than its parent
403 */ 391 */
404 static bool verify_new_ex(struct dev_cgroup *d 392 static bool verify_new_ex(struct dev_cgroup *dev_cgroup,
405 struct dev_exception 393 struct dev_exception_item *refex,
406 enum devcg_behavior 394 enum devcg_behavior behavior)
407 { 395 {
408 bool match = false; 396 bool match = false;
409 397
410 RCU_LOCKDEP_WARN(!rcu_read_lock_held() 398 RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
411 !lockdep_is_held(&dev 399 !lockdep_is_held(&devcgroup_mutex),
412 "device_cgroup:verify 400 "device_cgroup:verify_new_ex called without proper synchronization");
413 401
414 if (dev_cgroup->behavior == DEVCG_DEFA 402 if (dev_cgroup->behavior == DEVCG_DEFAULT_ALLOW) {
415 if (behavior == DEVCG_DEFAULT_ 403 if (behavior == DEVCG_DEFAULT_ALLOW) {
416 /* 404 /*
417 * new exception in th 405 * new exception in the child doesn't matter, only
418 * adding extra restri 406 * adding extra restrictions
419 */ 407 */
420 return true; 408 return true;
421 } else { 409 } else {
422 /* 410 /*
423 * new exception in th 411 * new exception in the child will add more devices
424 * that can be accesse !! 412 * that can be acessed, so it can't match any of
425 * parent's exceptions 413 * parent's exceptions, even slightly
426 */ 414 */
427 match = match_exceptio 415 match = match_exception_partial(&dev_cgroup->exceptions,
428 416 refex->type,
429 417 refex->major,
430 418 refex->minor,
431 419 refex->access);
432 420
433 if (match) 421 if (match)
434 return false; 422 return false;
435 return true; 423 return true;
436 } 424 }
437 } else { 425 } else {
438 /* 426 /*
439 * Only behavior == DEVCG_DEFA 427 * Only behavior == DEVCG_DEFAULT_DENY allowed here, therefore
440 * the new exception will add 428 * the new exception will add access to more devices and must
441 * be contained completely in 429 * be contained completely in an parent's exception to be
442 * allowed 430 * allowed
443 */ 431 */
444 match = match_exception(&dev_c 432 match = match_exception(&dev_cgroup->exceptions, refex->type,
445 refex- 433 refex->major, refex->minor,
446 refex- 434 refex->access);
447 435
448 if (match) 436 if (match)
449 /* parent has an excep 437 /* parent has an exception that matches the proposed */
450 return true; 438 return true;
451 else 439 else
452 return false; 440 return false;
453 } 441 }
454 return false; 442 return false;
455 } 443 }
456 444
457 /* 445 /*
458 * parent_has_perm: 446 * parent_has_perm:
459 * when adding a new allow rule to a device ex 447 * when adding a new allow rule to a device exception list, the rule
460 * must be allowed in the parent device 448 * must be allowed in the parent device
461 */ 449 */
462 static int parent_has_perm(struct dev_cgroup * 450 static int parent_has_perm(struct dev_cgroup *childcg,
463 struct dev_e 451 struct dev_exception_item *ex)
464 { 452 {
465 struct dev_cgroup *parent = css_to_dev 453 struct dev_cgroup *parent = css_to_devcgroup(childcg->css.parent);
466 454
467 if (!parent) 455 if (!parent)
468 return 1; 456 return 1;
469 return verify_new_ex(parent, ex, child 457 return verify_new_ex(parent, ex, childcg->behavior);
470 } 458 }
471 459
472 /** 460 /**
473 * parent_allows_removal - verify if it's ok t 461 * parent_allows_removal - verify if it's ok to remove an exception
474 * @childcg: child cgroup from where the excep 462 * @childcg: child cgroup from where the exception will be removed
475 * @ex: exception being removed 463 * @ex: exception being removed
476 * 464 *
477 * When removing an exception in cgroups with 465 * When removing an exception in cgroups with default ALLOW policy, it must
478 * be checked if removing it will give the chi 466 * be checked if removing it will give the child cgroup more access than the
479 * parent. 467 * parent.
480 * 468 *
481 * Return: true if it's ok to remove exception 469 * Return: true if it's ok to remove exception, false otherwise
482 */ 470 */
483 static bool parent_allows_removal(struct dev_c 471 static bool parent_allows_removal(struct dev_cgroup *childcg,
484 struct dev_e 472 struct dev_exception_item *ex)
485 { 473 {
486 struct dev_cgroup *parent = css_to_dev 474 struct dev_cgroup *parent = css_to_devcgroup(childcg->css.parent);
487 475
488 if (!parent) 476 if (!parent)
489 return true; 477 return true;
490 478
491 /* It's always allowed to remove acces 479 /* It's always allowed to remove access to devices */
492 if (childcg->behavior == DEVCG_DEFAULT 480 if (childcg->behavior == DEVCG_DEFAULT_DENY)
493 return true; 481 return true;
494 482
495 /* 483 /*
496 * Make sure you're not removing part 484 * Make sure you're not removing part or a whole exception existing in
497 * the parent cgroup 485 * the parent cgroup
498 */ 486 */
499 return !match_exception_partial(&paren 487 return !match_exception_partial(&parent->exceptions, ex->type,
500 ex->ma 488 ex->major, ex->minor, ex->access);
501 } 489 }
502 490
503 /** 491 /**
504 * may_allow_all - checks if it's possible to 492 * may_allow_all - checks if it's possible to change the behavior to
505 * allow based on parent's rul 493 * allow based on parent's rules.
506 * @parent: device cgroup's parent 494 * @parent: device cgroup's parent
507 * returns: != 0 in case it's allowed, 0 other 495 * returns: != 0 in case it's allowed, 0 otherwise
508 */ 496 */
509 static inline int may_allow_all(struct dev_cgr 497 static inline int may_allow_all(struct dev_cgroup *parent)
510 { 498 {
511 if (!parent) 499 if (!parent)
512 return 1; 500 return 1;
513 return parent->behavior == DEVCG_DEFAU 501 return parent->behavior == DEVCG_DEFAULT_ALLOW;
514 } 502 }
515 503
516 /** 504 /**
517 * revalidate_active_exceptions - walks throug 505 * revalidate_active_exceptions - walks through the active exception list and
518 * revalidates 506 * revalidates the exceptions based on parent's
519 * behavior and 507 * behavior and exceptions. The exceptions that
520 * are no longe 508 * are no longer valid will be removed.
521 * Called with 509 * Called with devcgroup_mutex held.
522 * @devcg: cgroup which exceptions will be che 510 * @devcg: cgroup which exceptions will be checked
523 * 511 *
524 * This is one of the three key functions for 512 * This is one of the three key functions for hierarchy implementation.
525 * This function is responsible for re-evaluat 513 * This function is responsible for re-evaluating all the cgroup's active
526 * exceptions due to a parent's exception chan 514 * exceptions due to a parent's exception change.
527 * Refer to Documentation/admin-guide/cgroup-v 515 * Refer to Documentation/admin-guide/cgroup-v1/devices.rst for more details.
528 */ 516 */
529 static void revalidate_active_exceptions(struc 517 static void revalidate_active_exceptions(struct dev_cgroup *devcg)
530 { 518 {
531 struct dev_exception_item *ex; 519 struct dev_exception_item *ex;
532 struct list_head *this, *tmp; 520 struct list_head *this, *tmp;
533 521
534 list_for_each_safe(this, tmp, &devcg-> 522 list_for_each_safe(this, tmp, &devcg->exceptions) {
535 ex = container_of(this, struct 523 ex = container_of(this, struct dev_exception_item, list);
536 if (!parent_has_perm(devcg, ex 524 if (!parent_has_perm(devcg, ex))
537 dev_exception_rm(devcg 525 dev_exception_rm(devcg, ex);
538 } 526 }
539 } 527 }
540 528
541 /** 529 /**
542 * propagate_exception - propagates a new exce 530 * propagate_exception - propagates a new exception to the children
543 * @devcg_root: device cgroup that added a new 531 * @devcg_root: device cgroup that added a new exception
544 * @ex: new exception to be propagated 532 * @ex: new exception to be propagated
545 * 533 *
546 * returns: 0 in case of success, != 0 in case 534 * returns: 0 in case of success, != 0 in case of error
547 */ 535 */
548 static int propagate_exception(struct dev_cgro 536 static int propagate_exception(struct dev_cgroup *devcg_root,
549 struct dev_exce 537 struct dev_exception_item *ex)
550 { 538 {
551 struct cgroup_subsys_state *pos; 539 struct cgroup_subsys_state *pos;
552 int rc = 0; 540 int rc = 0;
553 541
554 rcu_read_lock(); 542 rcu_read_lock();
555 543
556 css_for_each_descendant_pre(pos, &devc 544 css_for_each_descendant_pre(pos, &devcg_root->css) {
557 struct dev_cgroup *devcg = css 545 struct dev_cgroup *devcg = css_to_devcgroup(pos);
558 546
559 /* 547 /*
560 * Because devcgroup_mutex is 548 * Because devcgroup_mutex is held, no devcg will become
561 * online or offline during th 549 * online or offline during the tree walk (see on/offline
562 * methods), and online ones a 550 * methods), and online ones are safe to access outside RCU
563 * read lock without bumping r 551 * read lock without bumping refcnt.
564 */ 552 */
565 if (pos == &devcg_root->css || 553 if (pos == &devcg_root->css || !is_devcg_online(devcg))
566 continue; 554 continue;
567 555
568 rcu_read_unlock(); 556 rcu_read_unlock();
569 557
570 /* 558 /*
571 * in case both root's behavio 559 * in case both root's behavior and devcg is allow, a new
572 * restriction means adding to 560 * restriction means adding to the exception list
573 */ 561 */
574 if (devcg_root->behavior == DE 562 if (devcg_root->behavior == DEVCG_DEFAULT_ALLOW &&
575 devcg->behavior == DEVCG_D 563 devcg->behavior == DEVCG_DEFAULT_ALLOW) {
576 rc = dev_exception_add 564 rc = dev_exception_add(devcg, ex);
577 if (rc) 565 if (rc)
578 return rc; 566 return rc;
579 } else { 567 } else {
580 /* 568 /*
581 * in the other possib 569 * in the other possible cases:
582 * root's behavior: al 570 * root's behavior: allow, devcg's: deny
583 * root's behavior: de 571 * root's behavior: deny, devcg's: deny
584 * the exception will 572 * the exception will be removed
585 */ 573 */
586 dev_exception_rm(devcg 574 dev_exception_rm(devcg, ex);
587 } 575 }
588 revalidate_active_exceptions(d 576 revalidate_active_exceptions(devcg);
589 577
590 rcu_read_lock(); 578 rcu_read_lock();
591 } 579 }
592 580
593 rcu_read_unlock(); 581 rcu_read_unlock();
594 return rc; 582 return rc;
595 } 583 }
596 584
597 /* 585 /*
598 * Modify the exception list using allow/deny 586 * Modify the exception list using allow/deny rules.
599 * CAP_SYS_ADMIN is needed for this. It's at 587 * 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 588 * so we can give a container CAP_MKNOD to let it create devices but not
601 * modify the exception list. 589 * modify the exception list.
602 * It seems likely we'll want to add a CAP_CON 590 * It seems likely we'll want to add a CAP_CONTAINER capability to allow
603 * us to also grant CAP_SYS_ADMIN to container 591 * us to also grant CAP_SYS_ADMIN to containers without giving away the
604 * device exception list controls, but for now 592 * device exception list controls, but for now we'll stick with CAP_SYS_ADMIN
605 * 593 *
606 * Taking rules away is always allowed (given 594 * Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting
607 * new access is only allowed if you're in the 595 * new access is only allowed if you're in the top-level cgroup, or your
608 * parent cgroup has the access you're asking 596 * parent cgroup has the access you're asking for.
609 */ 597 */
610 static int devcgroup_update_access(struct dev_ 598 static int devcgroup_update_access(struct dev_cgroup *devcgroup,
611 int filetyp 599 int filetype, char *buffer)
612 { 600 {
613 const char *b; 601 const char *b;
614 char temp[12]; /* 11 + 1 char 602 char temp[12]; /* 11 + 1 characters needed for a u32 */
615 int count, rc = 0; 603 int count, rc = 0;
616 struct dev_exception_item ex; 604 struct dev_exception_item ex;
617 struct dev_cgroup *parent = css_to_dev 605 struct dev_cgroup *parent = css_to_devcgroup(devcgroup->css.parent);
618 struct dev_cgroup tmp_devcgrp; <<
619 606
620 if (!capable(CAP_SYS_ADMIN)) 607 if (!capable(CAP_SYS_ADMIN))
621 return -EPERM; 608 return -EPERM;
622 609
623 memset(&ex, 0, sizeof(ex)); 610 memset(&ex, 0, sizeof(ex));
624 memset(&tmp_devcgrp, 0, sizeof(tmp_dev <<
625 b = buffer; 611 b = buffer;
626 612
627 switch (*b) { 613 switch (*b) {
628 case 'a': 614 case 'a':
629 switch (filetype) { 615 switch (filetype) {
630 case DEVCG_ALLOW: 616 case DEVCG_ALLOW:
631 if (css_has_online_chi 617 if (css_has_online_children(&devcgroup->css))
632 return -EINVAL 618 return -EINVAL;
633 619
634 if (!may_allow_all(par 620 if (!may_allow_all(parent))
635 return -EPERM; 621 return -EPERM;
636 if (!parent) { !! 622 dev_exception_clean(devcgroup);
637 devcgroup->beh !! 623 devcgroup->behavior = DEVCG_DEFAULT_ALLOW;
638 dev_exception_ !! 624 if (!parent)
639 break; 625 break;
640 } <<
641 626
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 627 rc = dev_exceptions_copy(&devcgroup->exceptions,
649 628 &parent->exceptions);
650 if (rc) { !! 629 if (rc)
651 dev_exceptions <<
652 <<
653 return rc; 630 return rc;
654 } <<
655 devcgroup->behavior = <<
656 dev_exception_clean(&t <<
657 break; 631 break;
658 case DEVCG_DENY: 632 case DEVCG_DENY:
659 if (css_has_online_chi 633 if (css_has_online_children(&devcgroup->css))
660 return -EINVAL 634 return -EINVAL;
661 635
662 dev_exception_clean(de 636 dev_exception_clean(devcgroup);
663 devcgroup->behavior = 637 devcgroup->behavior = DEVCG_DEFAULT_DENY;
664 break; 638 break;
665 default: 639 default:
666 return -EINVAL; 640 return -EINVAL;
667 } 641 }
668 return 0; 642 return 0;
669 case 'b': 643 case 'b':
670 ex.type = DEVCG_DEV_BLOCK; 644 ex.type = DEVCG_DEV_BLOCK;
671 break; 645 break;
672 case 'c': 646 case 'c':
673 ex.type = DEVCG_DEV_CHAR; 647 ex.type = DEVCG_DEV_CHAR;
674 break; 648 break;
675 default: 649 default:
676 return -EINVAL; 650 return -EINVAL;
677 } 651 }
678 b++; 652 b++;
679 if (!isspace(*b)) 653 if (!isspace(*b))
680 return -EINVAL; 654 return -EINVAL;
681 b++; 655 b++;
682 if (*b == '*') { 656 if (*b == '*') {
683 ex.major = ~0; 657 ex.major = ~0;
684 b++; 658 b++;
685 } else if (isdigit(*b)) { 659 } else if (isdigit(*b)) {
686 memset(temp, 0, sizeof(temp)); 660 memset(temp, 0, sizeof(temp));
687 for (count = 0; count < sizeof 661 for (count = 0; count < sizeof(temp) - 1; count++) {
688 temp[count] = *b; 662 temp[count] = *b;
689 b++; 663 b++;
690 if (!isdigit(*b)) 664 if (!isdigit(*b))
691 break; 665 break;
692 } 666 }
693 rc = kstrtou32(temp, 10, &ex.m 667 rc = kstrtou32(temp, 10, &ex.major);
694 if (rc) 668 if (rc)
695 return -EINVAL; 669 return -EINVAL;
696 } else { 670 } else {
697 return -EINVAL; 671 return -EINVAL;
698 } 672 }
699 if (*b != ':') 673 if (*b != ':')
700 return -EINVAL; 674 return -EINVAL;
701 b++; 675 b++;
702 676
703 /* read minor */ 677 /* read minor */
704 if (*b == '*') { 678 if (*b == '*') {
705 ex.minor = ~0; 679 ex.minor = ~0;
706 b++; 680 b++;
707 } else if (isdigit(*b)) { 681 } else if (isdigit(*b)) {
708 memset(temp, 0, sizeof(temp)); 682 memset(temp, 0, sizeof(temp));
709 for (count = 0; count < sizeof 683 for (count = 0; count < sizeof(temp) - 1; count++) {
710 temp[count] = *b; 684 temp[count] = *b;
711 b++; 685 b++;
712 if (!isdigit(*b)) 686 if (!isdigit(*b))
713 break; 687 break;
714 } 688 }
715 rc = kstrtou32(temp, 10, &ex.m 689 rc = kstrtou32(temp, 10, &ex.minor);
716 if (rc) 690 if (rc)
717 return -EINVAL; 691 return -EINVAL;
718 } else { 692 } else {
719 return -EINVAL; 693 return -EINVAL;
720 } 694 }
721 if (!isspace(*b)) 695 if (!isspace(*b))
722 return -EINVAL; 696 return -EINVAL;
723 for (b++, count = 0; count < 3; count+ 697 for (b++, count = 0; count < 3; count++, b++) {
724 switch (*b) { 698 switch (*b) {
725 case 'r': 699 case 'r':
726 ex.access |= DEVCG_ACC 700 ex.access |= DEVCG_ACC_READ;
727 break; 701 break;
728 case 'w': 702 case 'w':
729 ex.access |= DEVCG_ACC 703 ex.access |= DEVCG_ACC_WRITE;
730 break; 704 break;
731 case 'm': 705 case 'm':
732 ex.access |= DEVCG_ACC 706 ex.access |= DEVCG_ACC_MKNOD;
733 break; 707 break;
734 case '\n': 708 case '\n':
735 case '\0': 709 case '\0':
736 count = 3; 710 count = 3;
737 break; 711 break;
738 default: 712 default:
739 return -EINVAL; 713 return -EINVAL;
740 } 714 }
741 } 715 }
742 716
743 switch (filetype) { 717 switch (filetype) {
744 case DEVCG_ALLOW: 718 case DEVCG_ALLOW:
745 /* 719 /*
746 * If the default policy is to 720 * If the default policy is to allow by default, try to remove
747 * an matching exception inste 721 * an matching exception instead. And be silent about it: we
748 * don't want to break compati 722 * don't want to break compatibility
749 */ 723 */
750 if (devcgroup->behavior == DEV 724 if (devcgroup->behavior == DEVCG_DEFAULT_ALLOW) {
751 /* Check if the parent 725 /* Check if the parent allows removing it first */
752 if (!parent_allows_rem 726 if (!parent_allows_removal(devcgroup, &ex))
753 return -EPERM; 727 return -EPERM;
754 dev_exception_rm(devcg 728 dev_exception_rm(devcgroup, &ex);
755 break; 729 break;
756 } 730 }
757 731
758 if (!parent_has_perm(devcgroup 732 if (!parent_has_perm(devcgroup, &ex))
759 return -EPERM; 733 return -EPERM;
760 rc = dev_exception_add(devcgro 734 rc = dev_exception_add(devcgroup, &ex);
761 break; 735 break;
762 case DEVCG_DENY: 736 case DEVCG_DENY:
763 /* 737 /*
764 * If the default policy is to 738 * If the default policy is to deny by default, try to remove
765 * an matching exception inste 739 * an matching exception instead. And be silent about it: we
766 * don't want to break compati 740 * don't want to break compatibility
767 */ 741 */
768 if (devcgroup->behavior == DEV 742 if (devcgroup->behavior == DEVCG_DEFAULT_DENY)
769 dev_exception_rm(devcg 743 dev_exception_rm(devcgroup, &ex);
770 else 744 else
771 rc = dev_exception_add 745 rc = dev_exception_add(devcgroup, &ex);
772 746
773 if (rc) 747 if (rc)
774 break; 748 break;
775 /* we only propagate new restr 749 /* we only propagate new restrictions */
776 rc = propagate_exception(devcg 750 rc = propagate_exception(devcgroup, &ex);
777 break; 751 break;
778 default: 752 default:
779 rc = -EINVAL; 753 rc = -EINVAL;
780 } 754 }
781 return rc; 755 return rc;
782 } 756 }
783 757
784 static ssize_t devcgroup_access_write(struct k 758 static ssize_t devcgroup_access_write(struct kernfs_open_file *of,
785 char *bu 759 char *buf, size_t nbytes, loff_t off)
786 { 760 {
787 int retval; 761 int retval;
788 762
789 mutex_lock(&devcgroup_mutex); 763 mutex_lock(&devcgroup_mutex);
790 retval = devcgroup_update_access(css_t 764 retval = devcgroup_update_access(css_to_devcgroup(of_css(of)),
791 of_cf 765 of_cft(of)->private, strstrip(buf));
792 mutex_unlock(&devcgroup_mutex); 766 mutex_unlock(&devcgroup_mutex);
793 return retval ?: nbytes; 767 return retval ?: nbytes;
794 } 768 }
795 769
796 static struct cftype dev_cgroup_files[] = { 770 static struct cftype dev_cgroup_files[] = {
797 { 771 {
798 .name = "allow", 772 .name = "allow",
799 .write = devcgroup_access_writ 773 .write = devcgroup_access_write,
800 .private = DEVCG_ALLOW, 774 .private = DEVCG_ALLOW,
801 }, 775 },
802 { 776 {
803 .name = "deny", 777 .name = "deny",
804 .write = devcgroup_access_writ 778 .write = devcgroup_access_write,
805 .private = DEVCG_DENY, 779 .private = DEVCG_DENY,
806 }, 780 },
807 { 781 {
808 .name = "list", 782 .name = "list",
809 .seq_show = devcgroup_seq_show 783 .seq_show = devcgroup_seq_show,
810 .private = DEVCG_LIST, 784 .private = DEVCG_LIST,
811 }, 785 },
812 { } /* terminate */ 786 { } /* terminate */
813 }; 787 };
814 788
815 struct cgroup_subsys devices_cgrp_subsys = { 789 struct cgroup_subsys devices_cgrp_subsys = {
816 .css_alloc = devcgroup_css_alloc, 790 .css_alloc = devcgroup_css_alloc,
817 .css_free = devcgroup_css_free, 791 .css_free = devcgroup_css_free,
818 .css_online = devcgroup_online, 792 .css_online = devcgroup_online,
819 .css_offline = devcgroup_offline, 793 .css_offline = devcgroup_offline,
820 .legacy_cftypes = dev_cgroup_files, 794 .legacy_cftypes = dev_cgroup_files,
821 }; 795 };
822 796
823 /** 797 /**
824 * devcgroup_legacy_check_permission - checks 798 * devcgroup_legacy_check_permission - checks if an inode operation is permitted
>> 799 * @dev_cgroup: the dev cgroup to be tested against
825 * @type: device type 800 * @type: device type
826 * @major: device major number 801 * @major: device major number
827 * @minor: device minor number 802 * @minor: device minor number
828 * @access: combination of DEVCG_ACC_WRITE, DE 803 * @access: combination of DEVCG_ACC_WRITE, DEVCG_ACC_READ and DEVCG_ACC_MKNOD
829 * 804 *
830 * returns 0 on success, -EPERM case the opera 805 * returns 0 on success, -EPERM case the operation is not permitted
831 */ 806 */
832 static int devcgroup_legacy_check_permission(s 807 static int devcgroup_legacy_check_permission(short type, u32 major, u32 minor,
833 short 808 short access)
834 { 809 {
835 struct dev_cgroup *dev_cgroup; 810 struct dev_cgroup *dev_cgroup;
836 bool rc; 811 bool rc;
837 812
838 rcu_read_lock(); 813 rcu_read_lock();
839 dev_cgroup = task_devcgroup(current); 814 dev_cgroup = task_devcgroup(current);
840 if (dev_cgroup->behavior == DEVCG_DEFA 815 if (dev_cgroup->behavior == DEVCG_DEFAULT_ALLOW)
841 /* Can't match any of the exce 816 /* Can't match any of the exceptions, even partially */
842 rc = !match_exception_partial( 817 rc = !match_exception_partial(&dev_cgroup->exceptions,
843 818 type, major, minor, access);
844 else 819 else
845 /* Need to match completely on 820 /* Need to match completely one exception to be allowed */
846 rc = match_exception(&dev_cgro 821 rc = match_exception(&dev_cgroup->exceptions, type, major,
847 minor, ac 822 minor, access);
848 rcu_read_unlock(); 823 rcu_read_unlock();
849 824
850 if (!rc) 825 if (!rc)
851 return -EPERM; 826 return -EPERM;
852 827
853 return 0; 828 return 0;
854 } 829 }
855 830
856 #endif /* CONFIG_CGROUP_DEVICE */ 831 #endif /* CONFIG_CGROUP_DEVICE */
857 832
858 #if defined(CONFIG_CGROUP_DEVICE) || defined(C 833 #if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
859 834
860 int devcgroup_check_permission(short type, u32 835 int devcgroup_check_permission(short type, u32 major, u32 minor, short access)
861 { 836 {
862 int rc = BPF_CGROUP_RUN_PROG_DEVICE_CG 837 int rc = BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type, major, minor, access);
863 838
864 if (rc) 839 if (rc)
865 return rc; !! 840 return -EPERM;
866 841
867 #ifdef CONFIG_CGROUP_DEVICE 842 #ifdef CONFIG_CGROUP_DEVICE
868 return devcgroup_legacy_check_permissi 843 return devcgroup_legacy_check_permission(type, major, minor, access);
869 844
870 #else /* CONFIG_CGROUP_DEVICE */ 845 #else /* CONFIG_CGROUP_DEVICE */
871 return 0; 846 return 0;
872 847
873 #endif /* CONFIG_CGROUP_DEVICE */ 848 #endif /* CONFIG_CGROUP_DEVICE */
874 } 849 }
875 EXPORT_SYMBOL(devcgroup_check_permission); 850 EXPORT_SYMBOL(devcgroup_check_permission);
876 #endif /* defined(CONFIG_CGROUP_DEVICE) || def 851 #endif /* defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF) */
877 852
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