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