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