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