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