Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 1 | /* |
| 2 | * dev_cgroup.c - device cgroup subsystem |
| 3 | * |
| 4 | * Copyright 2007 IBM Corp |
| 5 | */ |
| 6 | |
| 7 | #include <linux/device_cgroup.h> |
| 8 | #include <linux/cgroup.h> |
| 9 | #include <linux/ctype.h> |
| 10 | #include <linux/list.h> |
| 11 | #include <linux/uaccess.h> |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 12 | #include <linux/seq_file.h> |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 13 | |
| 14 | #define ACC_MKNOD 1 |
| 15 | #define ACC_READ 2 |
| 16 | #define ACC_WRITE 4 |
| 17 | #define ACC_MASK (ACC_MKNOD | ACC_READ | ACC_WRITE) |
| 18 | |
| 19 | #define DEV_BLOCK 1 |
| 20 | #define DEV_CHAR 2 |
| 21 | #define DEV_ALL 4 /* this represents all devices */ |
| 22 | |
| 23 | /* |
| 24 | * whitelist locking rules: |
| 25 | * cgroup_lock() cannot be taken under dev_cgroup->lock. |
| 26 | * dev_cgroup->lock can be taken with or without cgroup_lock(). |
| 27 | * |
| 28 | * modifications always require cgroup_lock |
| 29 | * modifications to a list which is visible require the |
| 30 | * dev_cgroup->lock *and* cgroup_lock() |
| 31 | * walking the list requires dev_cgroup->lock or cgroup_lock(). |
| 32 | * |
| 33 | * reasoning: dev_whitelist_copy() needs to kmalloc, so needs |
| 34 | * a mutex, which the cgroup_lock() is. Since modifying |
| 35 | * a visible list requires both locks, either lock can be |
| 36 | * taken for walking the list. |
| 37 | */ |
| 38 | |
| 39 | struct dev_whitelist_item { |
| 40 | u32 major, minor; |
| 41 | short type; |
| 42 | short access; |
| 43 | struct list_head list; |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 44 | struct rcu_head rcu; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 45 | }; |
| 46 | |
| 47 | struct dev_cgroup { |
| 48 | struct cgroup_subsys_state css; |
| 49 | struct list_head whitelist; |
| 50 | spinlock_t lock; |
| 51 | }; |
| 52 | |
Pavel Emelyanov | b66862f | 2008-06-05 22:46:24 -0700 | [diff] [blame] | 53 | static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s) |
| 54 | { |
| 55 | return container_of(s, struct dev_cgroup, css); |
| 56 | } |
| 57 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 58 | static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup) |
| 59 | { |
Pavel Emelyanov | b66862f | 2008-06-05 22:46:24 -0700 | [diff] [blame] | 60 | return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id)); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 61 | } |
| 62 | |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 63 | static inline struct dev_cgroup *task_devcgroup(struct task_struct *task) |
| 64 | { |
| 65 | return css_to_devcgroup(task_subsys_state(task, devices_subsys_id)); |
| 66 | } |
| 67 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 68 | struct cgroup_subsys devices_subsys; |
| 69 | |
| 70 | static int devcgroup_can_attach(struct cgroup_subsys *ss, |
| 71 | struct cgroup *new_cgroup, struct task_struct *task) |
| 72 | { |
| 73 | if (current != task && !capable(CAP_SYS_ADMIN)) |
| 74 | return -EPERM; |
| 75 | |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | /* |
| 80 | * called under cgroup_lock() |
| 81 | */ |
| 82 | static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig) |
| 83 | { |
| 84 | struct dev_whitelist_item *wh, *tmp, *new; |
| 85 | |
| 86 | list_for_each_entry(wh, orig, list) { |
Li Zefan | 2cdc724 | 2008-10-18 20:28:06 -0700 | [diff] [blame] | 87 | new = kmemdup(wh, sizeof(*wh), GFP_KERNEL); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 88 | if (!new) |
| 89 | goto free_and_exit; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 90 | list_add_tail(&new->list, dest); |
| 91 | } |
| 92 | |
| 93 | return 0; |
| 94 | |
| 95 | free_and_exit: |
| 96 | list_for_each_entry_safe(wh, tmp, dest, list) { |
| 97 | list_del(&wh->list); |
| 98 | kfree(wh); |
| 99 | } |
| 100 | return -ENOMEM; |
| 101 | } |
| 102 | |
| 103 | /* Stupid prototype - don't bother combining existing entries */ |
| 104 | /* |
| 105 | * called under cgroup_lock() |
| 106 | * since the list is visible to other tasks, we need the spinlock also |
| 107 | */ |
| 108 | static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, |
| 109 | struct dev_whitelist_item *wh) |
| 110 | { |
Pavel Emelyanov | d1ee297 | 2008-06-05 22:46:28 -0700 | [diff] [blame] | 111 | struct dev_whitelist_item *whcopy, *walk; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 112 | |
Li Zefan | 2cdc724 | 2008-10-18 20:28:06 -0700 | [diff] [blame] | 113 | whcopy = kmemdup(wh, sizeof(*wh), GFP_KERNEL); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 114 | if (!whcopy) |
| 115 | return -ENOMEM; |
| 116 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 117 | spin_lock(&dev_cgroup->lock); |
Pavel Emelyanov | d1ee297 | 2008-06-05 22:46:28 -0700 | [diff] [blame] | 118 | list_for_each_entry(walk, &dev_cgroup->whitelist, list) { |
| 119 | if (walk->type != wh->type) |
| 120 | continue; |
| 121 | if (walk->major != wh->major) |
| 122 | continue; |
| 123 | if (walk->minor != wh->minor) |
| 124 | continue; |
| 125 | |
| 126 | walk->access |= wh->access; |
| 127 | kfree(whcopy); |
| 128 | whcopy = NULL; |
| 129 | } |
| 130 | |
| 131 | if (whcopy != NULL) |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 132 | list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 133 | spin_unlock(&dev_cgroup->lock); |
| 134 | return 0; |
| 135 | } |
| 136 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 137 | static void whitelist_item_free(struct rcu_head *rcu) |
| 138 | { |
| 139 | struct dev_whitelist_item *item; |
| 140 | |
| 141 | item = container_of(rcu, struct dev_whitelist_item, rcu); |
| 142 | kfree(item); |
| 143 | } |
| 144 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 145 | /* |
| 146 | * called under cgroup_lock() |
| 147 | * since the list is visible to other tasks, we need the spinlock also |
| 148 | */ |
| 149 | static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup, |
| 150 | struct dev_whitelist_item *wh) |
| 151 | { |
| 152 | struct dev_whitelist_item *walk, *tmp; |
| 153 | |
| 154 | spin_lock(&dev_cgroup->lock); |
| 155 | list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) { |
| 156 | if (walk->type == DEV_ALL) |
| 157 | goto remove; |
| 158 | if (walk->type != wh->type) |
| 159 | continue; |
| 160 | if (walk->major != ~0 && walk->major != wh->major) |
| 161 | continue; |
| 162 | if (walk->minor != ~0 && walk->minor != wh->minor) |
| 163 | continue; |
| 164 | |
| 165 | remove: |
| 166 | walk->access &= ~wh->access; |
| 167 | if (!walk->access) { |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 168 | list_del_rcu(&walk->list); |
| 169 | call_rcu(&walk->rcu, whitelist_item_free); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 170 | } |
| 171 | } |
| 172 | spin_unlock(&dev_cgroup->lock); |
| 173 | } |
| 174 | |
| 175 | /* |
| 176 | * called from kernel/cgroup.c with cgroup_lock() held. |
| 177 | */ |
| 178 | static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss, |
| 179 | struct cgroup *cgroup) |
| 180 | { |
| 181 | struct dev_cgroup *dev_cgroup, *parent_dev_cgroup; |
| 182 | struct cgroup *parent_cgroup; |
| 183 | int ret; |
| 184 | |
| 185 | dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL); |
| 186 | if (!dev_cgroup) |
| 187 | return ERR_PTR(-ENOMEM); |
| 188 | INIT_LIST_HEAD(&dev_cgroup->whitelist); |
| 189 | parent_cgroup = cgroup->parent; |
| 190 | |
| 191 | if (parent_cgroup == NULL) { |
| 192 | struct dev_whitelist_item *wh; |
| 193 | wh = kmalloc(sizeof(*wh), GFP_KERNEL); |
| 194 | if (!wh) { |
| 195 | kfree(dev_cgroup); |
| 196 | return ERR_PTR(-ENOMEM); |
| 197 | } |
| 198 | wh->minor = wh->major = ~0; |
| 199 | wh->type = DEV_ALL; |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 200 | wh->access = ACC_MASK; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 201 | list_add(&wh->list, &dev_cgroup->whitelist); |
| 202 | } else { |
| 203 | parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup); |
| 204 | ret = dev_whitelist_copy(&dev_cgroup->whitelist, |
| 205 | &parent_dev_cgroup->whitelist); |
| 206 | if (ret) { |
| 207 | kfree(dev_cgroup); |
| 208 | return ERR_PTR(ret); |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | spin_lock_init(&dev_cgroup->lock); |
| 213 | return &dev_cgroup->css; |
| 214 | } |
| 215 | |
| 216 | static void devcgroup_destroy(struct cgroup_subsys *ss, |
| 217 | struct cgroup *cgroup) |
| 218 | { |
| 219 | struct dev_cgroup *dev_cgroup; |
| 220 | struct dev_whitelist_item *wh, *tmp; |
| 221 | |
| 222 | dev_cgroup = cgroup_to_devcgroup(cgroup); |
| 223 | list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) { |
| 224 | list_del(&wh->list); |
| 225 | kfree(wh); |
| 226 | } |
| 227 | kfree(dev_cgroup); |
| 228 | } |
| 229 | |
| 230 | #define DEVCG_ALLOW 1 |
| 231 | #define DEVCG_DENY 2 |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 232 | #define DEVCG_LIST 3 |
| 233 | |
Li Zefan | 17d213f | 2008-07-13 12:14:02 -0700 | [diff] [blame] | 234 | #define MAJMINLEN 13 |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 235 | #define ACCLEN 4 |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 236 | |
| 237 | static void set_access(char *acc, short access) |
| 238 | { |
| 239 | int idx = 0; |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 240 | memset(acc, 0, ACCLEN); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 241 | if (access & ACC_READ) |
| 242 | acc[idx++] = 'r'; |
| 243 | if (access & ACC_WRITE) |
| 244 | acc[idx++] = 'w'; |
| 245 | if (access & ACC_MKNOD) |
| 246 | acc[idx++] = 'm'; |
| 247 | } |
| 248 | |
| 249 | static char type_to_char(short type) |
| 250 | { |
| 251 | if (type == DEV_ALL) |
| 252 | return 'a'; |
| 253 | if (type == DEV_CHAR) |
| 254 | return 'c'; |
| 255 | if (type == DEV_BLOCK) |
| 256 | return 'b'; |
| 257 | return 'X'; |
| 258 | } |
| 259 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 260 | static void set_majmin(char *str, unsigned m) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 261 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 262 | if (m == ~0) |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 263 | strcpy(str, "*"); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 264 | else |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 265 | sprintf(str, "%u", m); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 266 | } |
| 267 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 268 | static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft, |
| 269 | struct seq_file *m) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 270 | { |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 271 | struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 272 | struct dev_whitelist_item *wh; |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 273 | char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN]; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 274 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 275 | rcu_read_lock(); |
| 276 | list_for_each_entry_rcu(wh, &devcgroup->whitelist, list) { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 277 | set_access(acc, wh->access); |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 278 | set_majmin(maj, wh->major); |
| 279 | set_majmin(min, wh->minor); |
| 280 | seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type), |
| 281 | maj, min, acc); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 282 | } |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 283 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 284 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 285 | return 0; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 286 | } |
| 287 | |
| 288 | /* |
| 289 | * may_access_whitelist: |
| 290 | * does the access granted to dev_cgroup c contain the access |
| 291 | * requested in whitelist item refwh. |
| 292 | * return 1 if yes, 0 if no. |
| 293 | * call with c->lock held |
| 294 | */ |
| 295 | static int may_access_whitelist(struct dev_cgroup *c, |
| 296 | struct dev_whitelist_item *refwh) |
| 297 | { |
| 298 | struct dev_whitelist_item *whitem; |
| 299 | |
| 300 | list_for_each_entry(whitem, &c->whitelist, list) { |
| 301 | if (whitem->type & DEV_ALL) |
| 302 | return 1; |
| 303 | if ((refwh->type & DEV_BLOCK) && !(whitem->type & DEV_BLOCK)) |
| 304 | continue; |
| 305 | if ((refwh->type & DEV_CHAR) && !(whitem->type & DEV_CHAR)) |
| 306 | continue; |
| 307 | if (whitem->major != ~0 && whitem->major != refwh->major) |
| 308 | continue; |
| 309 | if (whitem->minor != ~0 && whitem->minor != refwh->minor) |
| 310 | continue; |
Li Zefan | ec229e8 | 2008-07-13 12:14:04 -0700 | [diff] [blame] | 311 | if (refwh->access & (~whitem->access)) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 312 | continue; |
| 313 | return 1; |
| 314 | } |
| 315 | return 0; |
| 316 | } |
| 317 | |
| 318 | /* |
| 319 | * parent_has_perm: |
| 320 | * when adding a new allow rule to a device whitelist, the rule |
| 321 | * must be allowed in the parent device |
| 322 | */ |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 323 | static int parent_has_perm(struct dev_cgroup *childcg, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 324 | struct dev_whitelist_item *wh) |
| 325 | { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 326 | struct cgroup *pcg = childcg->css.cgroup->parent; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 327 | struct dev_cgroup *parent; |
| 328 | int ret; |
| 329 | |
| 330 | if (!pcg) |
| 331 | return 1; |
| 332 | parent = cgroup_to_devcgroup(pcg); |
| 333 | spin_lock(&parent->lock); |
| 334 | ret = may_access_whitelist(parent, wh); |
| 335 | spin_unlock(&parent->lock); |
| 336 | return ret; |
| 337 | } |
| 338 | |
| 339 | /* |
| 340 | * Modify the whitelist using allow/deny rules. |
| 341 | * CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD |
| 342 | * so we can give a container CAP_MKNOD to let it create devices but not |
| 343 | * modify the whitelist. |
| 344 | * It seems likely we'll want to add a CAP_CONTAINER capability to allow |
| 345 | * us to also grant CAP_SYS_ADMIN to containers without giving away the |
| 346 | * device whitelist controls, but for now we'll stick with CAP_SYS_ADMIN |
| 347 | * |
| 348 | * Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting |
| 349 | * new access is only allowed if you're in the top-level cgroup, or your |
| 350 | * parent cgroup has the access you're asking for. |
| 351 | */ |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 352 | static int devcgroup_update_access(struct dev_cgroup *devcgroup, |
| 353 | int filetype, const char *buffer) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 354 | { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 355 | struct dev_cgroup *cur_devcgroup; |
| 356 | const char *b; |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 357 | char *endp; |
Li Zefan | c012a54 | 2008-10-18 20:28:07 -0700 | [diff] [blame^] | 358 | int count; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 359 | struct dev_whitelist_item wh; |
| 360 | |
| 361 | if (!capable(CAP_SYS_ADMIN)) |
| 362 | return -EPERM; |
| 363 | |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 364 | cur_devcgroup = task_devcgroup(current); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 365 | |
| 366 | memset(&wh, 0, sizeof(wh)); |
| 367 | b = buffer; |
| 368 | |
| 369 | switch (*b) { |
| 370 | case 'a': |
| 371 | wh.type = DEV_ALL; |
| 372 | wh.access = ACC_MASK; |
Li Zefan | d823f6b | 2008-07-04 10:00:07 -0700 | [diff] [blame] | 373 | wh.major = ~0; |
| 374 | wh.minor = ~0; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 375 | goto handle; |
| 376 | case 'b': |
| 377 | wh.type = DEV_BLOCK; |
| 378 | break; |
| 379 | case 'c': |
| 380 | wh.type = DEV_CHAR; |
| 381 | break; |
| 382 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 383 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 384 | } |
| 385 | b++; |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 386 | if (!isspace(*b)) |
| 387 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 388 | b++; |
| 389 | if (*b == '*') { |
| 390 | wh.major = ~0; |
| 391 | b++; |
| 392 | } else if (isdigit(*b)) { |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 393 | wh.major = simple_strtoul(b, &endp, 10); |
| 394 | b = endp; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 395 | } else { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 396 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 397 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 398 | if (*b != ':') |
| 399 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 400 | b++; |
| 401 | |
| 402 | /* read minor */ |
| 403 | if (*b == '*') { |
| 404 | wh.minor = ~0; |
| 405 | b++; |
| 406 | } else if (isdigit(*b)) { |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 407 | wh.minor = simple_strtoul(b, &endp, 10); |
| 408 | b = endp; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 409 | } else { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 410 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 411 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 412 | if (!isspace(*b)) |
| 413 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 414 | for (b++, count = 0; count < 3; count++, b++) { |
| 415 | switch (*b) { |
| 416 | case 'r': |
| 417 | wh.access |= ACC_READ; |
| 418 | break; |
| 419 | case 'w': |
| 420 | wh.access |= ACC_WRITE; |
| 421 | break; |
| 422 | case 'm': |
| 423 | wh.access |= ACC_MKNOD; |
| 424 | break; |
| 425 | case '\n': |
| 426 | case '\0': |
| 427 | count = 3; |
| 428 | break; |
| 429 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 430 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 431 | } |
| 432 | } |
| 433 | |
| 434 | handle: |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 435 | switch (filetype) { |
| 436 | case DEVCG_ALLOW: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 437 | if (!parent_has_perm(devcgroup, &wh)) |
| 438 | return -EPERM; |
| 439 | return dev_whitelist_add(devcgroup, &wh); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 440 | case DEVCG_DENY: |
| 441 | dev_whitelist_rm(devcgroup, &wh); |
| 442 | break; |
| 443 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 444 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 445 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 446 | return 0; |
| 447 | } |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 448 | |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 449 | static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft, |
| 450 | const char *buffer) |
| 451 | { |
| 452 | int retval; |
| 453 | if (!cgroup_lock_live_group(cgrp)) |
| 454 | return -ENODEV; |
| 455 | retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp), |
| 456 | cft->private, buffer); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 457 | cgroup_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 458 | return retval; |
| 459 | } |
| 460 | |
| 461 | static struct cftype dev_cgroup_files[] = { |
| 462 | { |
| 463 | .name = "allow", |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 464 | .write_string = devcgroup_access_write, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 465 | .private = DEVCG_ALLOW, |
| 466 | }, |
| 467 | { |
| 468 | .name = "deny", |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 469 | .write_string = devcgroup_access_write, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 470 | .private = DEVCG_DENY, |
| 471 | }, |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 472 | { |
| 473 | .name = "list", |
| 474 | .read_seq_string = devcgroup_seq_read, |
| 475 | .private = DEVCG_LIST, |
| 476 | }, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 477 | }; |
| 478 | |
| 479 | static int devcgroup_populate(struct cgroup_subsys *ss, |
| 480 | struct cgroup *cgroup) |
| 481 | { |
| 482 | return cgroup_add_files(cgroup, ss, dev_cgroup_files, |
| 483 | ARRAY_SIZE(dev_cgroup_files)); |
| 484 | } |
| 485 | |
| 486 | struct cgroup_subsys devices_subsys = { |
| 487 | .name = "devices", |
| 488 | .can_attach = devcgroup_can_attach, |
| 489 | .create = devcgroup_create, |
| 490 | .destroy = devcgroup_destroy, |
| 491 | .populate = devcgroup_populate, |
| 492 | .subsys_id = devices_subsys_id, |
| 493 | }; |
| 494 | |
| 495 | int devcgroup_inode_permission(struct inode *inode, int mask) |
| 496 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 497 | struct dev_cgroup *dev_cgroup; |
| 498 | struct dev_whitelist_item *wh; |
| 499 | |
| 500 | dev_t device = inode->i_rdev; |
| 501 | if (!device) |
| 502 | return 0; |
| 503 | if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode)) |
| 504 | return 0; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 505 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 506 | rcu_read_lock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 507 | |
| 508 | dev_cgroup = task_devcgroup(current); |
| 509 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 510 | list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 511 | if (wh->type & DEV_ALL) |
| 512 | goto acc_check; |
| 513 | if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode)) |
| 514 | continue; |
| 515 | if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode)) |
| 516 | continue; |
| 517 | if (wh->major != ~0 && wh->major != imajor(inode)) |
| 518 | continue; |
| 519 | if (wh->minor != ~0 && wh->minor != iminor(inode)) |
| 520 | continue; |
| 521 | acc_check: |
| 522 | if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE)) |
| 523 | continue; |
| 524 | if ((mask & MAY_READ) && !(wh->access & ACC_READ)) |
| 525 | continue; |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 526 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 527 | return 0; |
| 528 | } |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 529 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 530 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 531 | |
| 532 | return -EPERM; |
| 533 | } |
| 534 | |
| 535 | int devcgroup_inode_mknod(int mode, dev_t dev) |
| 536 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 537 | struct dev_cgroup *dev_cgroup; |
| 538 | struct dev_whitelist_item *wh; |
| 539 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 540 | rcu_read_lock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 541 | |
| 542 | dev_cgroup = task_devcgroup(current); |
| 543 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 544 | list_for_each_entry(wh, &dev_cgroup->whitelist, list) { |
| 545 | if (wh->type & DEV_ALL) |
| 546 | goto acc_check; |
| 547 | if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode)) |
| 548 | continue; |
| 549 | if ((wh->type & DEV_CHAR) && !S_ISCHR(mode)) |
| 550 | continue; |
| 551 | if (wh->major != ~0 && wh->major != MAJOR(dev)) |
| 552 | continue; |
| 553 | if (wh->minor != ~0 && wh->minor != MINOR(dev)) |
| 554 | continue; |
| 555 | acc_check: |
| 556 | if (!(wh->access & ACC_MKNOD)) |
| 557 | continue; |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 558 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 559 | return 0; |
| 560 | } |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 561 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 562 | rcu_read_unlock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 563 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 564 | return -EPERM; |
| 565 | } |