Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 1 | /* |
Lai Jiangshan | 47c5980 | 2008-10-18 20:28:07 -0700 | [diff] [blame] | 2 | * device_cgroup.c - device cgroup subsystem |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 13 | #include <linux/slab.h> |
Lai Jiangshan | 47c5980 | 2008-10-18 20:28:07 -0700 | [diff] [blame] | 14 | #include <linux/rcupdate.h> |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 15 | #include <linux/mutex.h> |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 16 | |
| 17 | #define ACC_MKNOD 1 |
| 18 | #define ACC_READ 2 |
| 19 | #define ACC_WRITE 4 |
| 20 | #define ACC_MASK (ACC_MKNOD | ACC_READ | ACC_WRITE) |
| 21 | |
| 22 | #define DEV_BLOCK 1 |
| 23 | #define DEV_CHAR 2 |
| 24 | #define DEV_ALL 4 /* this represents all devices */ |
| 25 | |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 26 | static DEFINE_MUTEX(devcgroup_mutex); |
| 27 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 28 | /* |
| 29 | * whitelist locking rules: |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 30 | * hold devcgroup_mutex for update/read. |
Lai Jiangshan | 47c5980 | 2008-10-18 20:28:07 -0700 | [diff] [blame] | 31 | * hold rcu_read_lock() for read. |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 32 | */ |
| 33 | |
| 34 | struct dev_whitelist_item { |
| 35 | u32 major, minor; |
| 36 | short type; |
| 37 | short access; |
| 38 | struct list_head list; |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 39 | struct rcu_head rcu; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 40 | }; |
| 41 | |
| 42 | struct dev_cgroup { |
| 43 | struct cgroup_subsys_state css; |
| 44 | struct list_head whitelist; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 45 | }; |
| 46 | |
Pavel Emelyanov | b66862f | 2008-06-05 22:46:24 -0700 | [diff] [blame] | 47 | static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s) |
| 48 | { |
| 49 | return container_of(s, struct dev_cgroup, css); |
| 50 | } |
| 51 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 52 | static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup) |
| 53 | { |
Pavel Emelyanov | b66862f | 2008-06-05 22:46:24 -0700 | [diff] [blame] | 54 | return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id)); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 55 | } |
| 56 | |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 57 | static inline struct dev_cgroup *task_devcgroup(struct task_struct *task) |
| 58 | { |
| 59 | return css_to_devcgroup(task_subsys_state(task, devices_subsys_id)); |
| 60 | } |
| 61 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 62 | struct cgroup_subsys devices_subsys; |
| 63 | |
| 64 | static int devcgroup_can_attach(struct cgroup_subsys *ss, |
Ben Blum | be367d0 | 2009-09-23 15:56:31 -0700 | [diff] [blame] | 65 | struct cgroup *new_cgroup, struct task_struct *task, |
| 66 | bool threadgroup) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 67 | { |
| 68 | if (current != task && !capable(CAP_SYS_ADMIN)) |
| 69 | return -EPERM; |
| 70 | |
| 71 | return 0; |
| 72 | } |
| 73 | |
| 74 | /* |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 75 | * called under devcgroup_mutex |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 76 | */ |
| 77 | static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig) |
| 78 | { |
| 79 | struct dev_whitelist_item *wh, *tmp, *new; |
| 80 | |
| 81 | list_for_each_entry(wh, orig, list) { |
Li Zefan | 2cdc724 | 2008-10-18 20:28:06 -0700 | [diff] [blame] | 82 | new = kmemdup(wh, sizeof(*wh), GFP_KERNEL); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 83 | if (!new) |
| 84 | goto free_and_exit; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 85 | list_add_tail(&new->list, dest); |
| 86 | } |
| 87 | |
| 88 | return 0; |
| 89 | |
| 90 | free_and_exit: |
| 91 | list_for_each_entry_safe(wh, tmp, dest, list) { |
| 92 | list_del(&wh->list); |
| 93 | kfree(wh); |
| 94 | } |
| 95 | return -ENOMEM; |
| 96 | } |
| 97 | |
| 98 | /* Stupid prototype - don't bother combining existing entries */ |
| 99 | /* |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 100 | * called under devcgroup_mutex |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 101 | */ |
| 102 | static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, |
| 103 | struct dev_whitelist_item *wh) |
| 104 | { |
Pavel Emelyanov | d1ee297 | 2008-06-05 22:46:28 -0700 | [diff] [blame] | 105 | struct dev_whitelist_item *whcopy, *walk; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 106 | |
Li Zefan | 2cdc724 | 2008-10-18 20:28:06 -0700 | [diff] [blame] | 107 | whcopy = kmemdup(wh, sizeof(*wh), GFP_KERNEL); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 108 | if (!whcopy) |
| 109 | return -ENOMEM; |
| 110 | |
Pavel Emelyanov | d1ee297 | 2008-06-05 22:46:28 -0700 | [diff] [blame] | 111 | list_for_each_entry(walk, &dev_cgroup->whitelist, list) { |
| 112 | if (walk->type != wh->type) |
| 113 | continue; |
| 114 | if (walk->major != wh->major) |
| 115 | continue; |
| 116 | if (walk->minor != wh->minor) |
| 117 | continue; |
| 118 | |
| 119 | walk->access |= wh->access; |
| 120 | kfree(whcopy); |
| 121 | whcopy = NULL; |
| 122 | } |
| 123 | |
| 124 | if (whcopy != NULL) |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 125 | list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 126 | return 0; |
| 127 | } |
| 128 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 129 | static void whitelist_item_free(struct rcu_head *rcu) |
| 130 | { |
| 131 | struct dev_whitelist_item *item; |
| 132 | |
| 133 | item = container_of(rcu, struct dev_whitelist_item, rcu); |
| 134 | kfree(item); |
| 135 | } |
| 136 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 137 | /* |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 138 | * called under devcgroup_mutex |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 139 | */ |
| 140 | static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup, |
| 141 | struct dev_whitelist_item *wh) |
| 142 | { |
| 143 | struct dev_whitelist_item *walk, *tmp; |
| 144 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 145 | list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) { |
| 146 | if (walk->type == DEV_ALL) |
| 147 | goto remove; |
| 148 | if (walk->type != wh->type) |
| 149 | continue; |
| 150 | if (walk->major != ~0 && walk->major != wh->major) |
| 151 | continue; |
| 152 | if (walk->minor != ~0 && walk->minor != wh->minor) |
| 153 | continue; |
| 154 | |
| 155 | remove: |
| 156 | walk->access &= ~wh->access; |
| 157 | if (!walk->access) { |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 158 | list_del_rcu(&walk->list); |
| 159 | call_rcu(&walk->rcu, whitelist_item_free); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 160 | } |
| 161 | } |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 162 | } |
| 163 | |
| 164 | /* |
| 165 | * called from kernel/cgroup.c with cgroup_lock() held. |
| 166 | */ |
| 167 | static struct cgroup_subsys_state *devcgroup_create(struct cgroup_subsys *ss, |
| 168 | struct cgroup *cgroup) |
| 169 | { |
| 170 | struct dev_cgroup *dev_cgroup, *parent_dev_cgroup; |
| 171 | struct cgroup *parent_cgroup; |
| 172 | int ret; |
| 173 | |
| 174 | dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL); |
| 175 | if (!dev_cgroup) |
| 176 | return ERR_PTR(-ENOMEM); |
| 177 | INIT_LIST_HEAD(&dev_cgroup->whitelist); |
| 178 | parent_cgroup = cgroup->parent; |
| 179 | |
| 180 | if (parent_cgroup == NULL) { |
| 181 | struct dev_whitelist_item *wh; |
| 182 | wh = kmalloc(sizeof(*wh), GFP_KERNEL); |
| 183 | if (!wh) { |
| 184 | kfree(dev_cgroup); |
| 185 | return ERR_PTR(-ENOMEM); |
| 186 | } |
| 187 | wh->minor = wh->major = ~0; |
| 188 | wh->type = DEV_ALL; |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 189 | wh->access = ACC_MASK; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 190 | list_add(&wh->list, &dev_cgroup->whitelist); |
| 191 | } else { |
| 192 | parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup); |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 193 | mutex_lock(&devcgroup_mutex); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 194 | ret = dev_whitelist_copy(&dev_cgroup->whitelist, |
| 195 | &parent_dev_cgroup->whitelist); |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 196 | mutex_unlock(&devcgroup_mutex); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 197 | if (ret) { |
| 198 | kfree(dev_cgroup); |
| 199 | return ERR_PTR(ret); |
| 200 | } |
| 201 | } |
| 202 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 203 | return &dev_cgroup->css; |
| 204 | } |
| 205 | |
| 206 | static void devcgroup_destroy(struct cgroup_subsys *ss, |
| 207 | struct cgroup *cgroup) |
| 208 | { |
| 209 | struct dev_cgroup *dev_cgroup; |
| 210 | struct dev_whitelist_item *wh, *tmp; |
| 211 | |
| 212 | dev_cgroup = cgroup_to_devcgroup(cgroup); |
| 213 | list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) { |
| 214 | list_del(&wh->list); |
| 215 | kfree(wh); |
| 216 | } |
| 217 | kfree(dev_cgroup); |
| 218 | } |
| 219 | |
| 220 | #define DEVCG_ALLOW 1 |
| 221 | #define DEVCG_DENY 2 |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 222 | #define DEVCG_LIST 3 |
| 223 | |
Li Zefan | 17d213f | 2008-07-13 12:14:02 -0700 | [diff] [blame] | 224 | #define MAJMINLEN 13 |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 225 | #define ACCLEN 4 |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 226 | |
| 227 | static void set_access(char *acc, short access) |
| 228 | { |
| 229 | int idx = 0; |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 230 | memset(acc, 0, ACCLEN); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 231 | if (access & ACC_READ) |
| 232 | acc[idx++] = 'r'; |
| 233 | if (access & ACC_WRITE) |
| 234 | acc[idx++] = 'w'; |
| 235 | if (access & ACC_MKNOD) |
| 236 | acc[idx++] = 'm'; |
| 237 | } |
| 238 | |
| 239 | static char type_to_char(short type) |
| 240 | { |
| 241 | if (type == DEV_ALL) |
| 242 | return 'a'; |
| 243 | if (type == DEV_CHAR) |
| 244 | return 'c'; |
| 245 | if (type == DEV_BLOCK) |
| 246 | return 'b'; |
| 247 | return 'X'; |
| 248 | } |
| 249 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 250 | static void set_majmin(char *str, unsigned m) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 251 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 252 | if (m == ~0) |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 253 | strcpy(str, "*"); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 254 | else |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 255 | sprintf(str, "%u", m); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 256 | } |
| 257 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 258 | static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft, |
| 259 | struct seq_file *m) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 260 | { |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 261 | struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 262 | struct dev_whitelist_item *wh; |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 263 | char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN]; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 264 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 265 | rcu_read_lock(); |
| 266 | list_for_each_entry_rcu(wh, &devcgroup->whitelist, list) { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 267 | set_access(acc, wh->access); |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 268 | set_majmin(maj, wh->major); |
| 269 | set_majmin(min, wh->minor); |
| 270 | seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type), |
| 271 | maj, min, acc); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 272 | } |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 273 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 274 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 275 | return 0; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 276 | } |
| 277 | |
| 278 | /* |
| 279 | * may_access_whitelist: |
| 280 | * does the access granted to dev_cgroup c contain the access |
| 281 | * requested in whitelist item refwh. |
| 282 | * return 1 if yes, 0 if no. |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 283 | * call with devcgroup_mutex held |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 284 | */ |
| 285 | static int may_access_whitelist(struct dev_cgroup *c, |
| 286 | struct dev_whitelist_item *refwh) |
| 287 | { |
| 288 | struct dev_whitelist_item *whitem; |
| 289 | |
| 290 | list_for_each_entry(whitem, &c->whitelist, list) { |
| 291 | if (whitem->type & DEV_ALL) |
| 292 | return 1; |
| 293 | if ((refwh->type & DEV_BLOCK) && !(whitem->type & DEV_BLOCK)) |
| 294 | continue; |
| 295 | if ((refwh->type & DEV_CHAR) && !(whitem->type & DEV_CHAR)) |
| 296 | continue; |
| 297 | if (whitem->major != ~0 && whitem->major != refwh->major) |
| 298 | continue; |
| 299 | if (whitem->minor != ~0 && whitem->minor != refwh->minor) |
| 300 | continue; |
Li Zefan | ec229e8 | 2008-07-13 12:14:04 -0700 | [diff] [blame] | 301 | if (refwh->access & (~whitem->access)) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 302 | continue; |
| 303 | return 1; |
| 304 | } |
| 305 | return 0; |
| 306 | } |
| 307 | |
| 308 | /* |
| 309 | * parent_has_perm: |
| 310 | * when adding a new allow rule to a device whitelist, the rule |
| 311 | * must be allowed in the parent device |
| 312 | */ |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 313 | static int parent_has_perm(struct dev_cgroup *childcg, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 314 | struct dev_whitelist_item *wh) |
| 315 | { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 316 | struct cgroup *pcg = childcg->css.cgroup->parent; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 317 | struct dev_cgroup *parent; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 318 | |
| 319 | if (!pcg) |
| 320 | return 1; |
| 321 | parent = cgroup_to_devcgroup(pcg); |
Lai Jiangshan | 47c5980 | 2008-10-18 20:28:07 -0700 | [diff] [blame] | 322 | return may_access_whitelist(parent, wh); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 323 | } |
| 324 | |
| 325 | /* |
| 326 | * Modify the whitelist using allow/deny rules. |
| 327 | * CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD |
| 328 | * so we can give a container CAP_MKNOD to let it create devices but not |
| 329 | * modify the whitelist. |
| 330 | * It seems likely we'll want to add a CAP_CONTAINER capability to allow |
| 331 | * us to also grant CAP_SYS_ADMIN to containers without giving away the |
| 332 | * device whitelist controls, but for now we'll stick with CAP_SYS_ADMIN |
| 333 | * |
| 334 | * Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting |
| 335 | * new access is only allowed if you're in the top-level cgroup, or your |
| 336 | * parent cgroup has the access you're asking for. |
| 337 | */ |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 338 | static int devcgroup_update_access(struct dev_cgroup *devcgroup, |
| 339 | int filetype, const char *buffer) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 340 | { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 341 | const char *b; |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 342 | char *endp; |
Li Zefan | c012a54 | 2008-10-18 20:28:07 -0700 | [diff] [blame] | 343 | int count; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 344 | struct dev_whitelist_item wh; |
| 345 | |
| 346 | if (!capable(CAP_SYS_ADMIN)) |
| 347 | return -EPERM; |
| 348 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 349 | memset(&wh, 0, sizeof(wh)); |
| 350 | b = buffer; |
| 351 | |
| 352 | switch (*b) { |
| 353 | case 'a': |
| 354 | wh.type = DEV_ALL; |
| 355 | wh.access = ACC_MASK; |
Li Zefan | d823f6b | 2008-07-04 10:00:07 -0700 | [diff] [blame] | 356 | wh.major = ~0; |
| 357 | wh.minor = ~0; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 358 | goto handle; |
| 359 | case 'b': |
| 360 | wh.type = DEV_BLOCK; |
| 361 | break; |
| 362 | case 'c': |
| 363 | wh.type = DEV_CHAR; |
| 364 | break; |
| 365 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 366 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 367 | } |
| 368 | b++; |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 369 | if (!isspace(*b)) |
| 370 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 371 | b++; |
| 372 | if (*b == '*') { |
| 373 | wh.major = ~0; |
| 374 | b++; |
| 375 | } else if (isdigit(*b)) { |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 376 | wh.major = simple_strtoul(b, &endp, 10); |
| 377 | b = endp; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 378 | } else { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 379 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 380 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 381 | if (*b != ':') |
| 382 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 383 | b++; |
| 384 | |
| 385 | /* read minor */ |
| 386 | if (*b == '*') { |
| 387 | wh.minor = ~0; |
| 388 | b++; |
| 389 | } else if (isdigit(*b)) { |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 390 | wh.minor = simple_strtoul(b, &endp, 10); |
| 391 | b = endp; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 392 | } else { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 393 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 394 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 395 | if (!isspace(*b)) |
| 396 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 397 | for (b++, count = 0; count < 3; count++, b++) { |
| 398 | switch (*b) { |
| 399 | case 'r': |
| 400 | wh.access |= ACC_READ; |
| 401 | break; |
| 402 | case 'w': |
| 403 | wh.access |= ACC_WRITE; |
| 404 | break; |
| 405 | case 'm': |
| 406 | wh.access |= ACC_MKNOD; |
| 407 | break; |
| 408 | case '\n': |
| 409 | case '\0': |
| 410 | count = 3; |
| 411 | break; |
| 412 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 413 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 414 | } |
| 415 | } |
| 416 | |
| 417 | handle: |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 418 | switch (filetype) { |
| 419 | case DEVCG_ALLOW: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 420 | if (!parent_has_perm(devcgroup, &wh)) |
| 421 | return -EPERM; |
| 422 | return dev_whitelist_add(devcgroup, &wh); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 423 | case DEVCG_DENY: |
| 424 | dev_whitelist_rm(devcgroup, &wh); |
| 425 | break; |
| 426 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 427 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 428 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 429 | return 0; |
| 430 | } |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 431 | |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 432 | static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft, |
| 433 | const char *buffer) |
| 434 | { |
| 435 | int retval; |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 436 | |
| 437 | mutex_lock(&devcgroup_mutex); |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 438 | retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp), |
| 439 | cft->private, buffer); |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 440 | mutex_unlock(&devcgroup_mutex); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 441 | return retval; |
| 442 | } |
| 443 | |
| 444 | static struct cftype dev_cgroup_files[] = { |
| 445 | { |
| 446 | .name = "allow", |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 447 | .write_string = devcgroup_access_write, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 448 | .private = DEVCG_ALLOW, |
| 449 | }, |
| 450 | { |
| 451 | .name = "deny", |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 452 | .write_string = devcgroup_access_write, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 453 | .private = DEVCG_DENY, |
| 454 | }, |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 455 | { |
| 456 | .name = "list", |
| 457 | .read_seq_string = devcgroup_seq_read, |
| 458 | .private = DEVCG_LIST, |
| 459 | }, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 460 | }; |
| 461 | |
| 462 | static int devcgroup_populate(struct cgroup_subsys *ss, |
| 463 | struct cgroup *cgroup) |
| 464 | { |
| 465 | return cgroup_add_files(cgroup, ss, dev_cgroup_files, |
| 466 | ARRAY_SIZE(dev_cgroup_files)); |
| 467 | } |
| 468 | |
| 469 | struct cgroup_subsys devices_subsys = { |
| 470 | .name = "devices", |
| 471 | .can_attach = devcgroup_can_attach, |
| 472 | .create = devcgroup_create, |
| 473 | .destroy = devcgroup_destroy, |
| 474 | .populate = devcgroup_populate, |
| 475 | .subsys_id = devices_subsys_id, |
| 476 | }; |
| 477 | |
| 478 | int devcgroup_inode_permission(struct inode *inode, int mask) |
| 479 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 480 | struct dev_cgroup *dev_cgroup; |
| 481 | struct dev_whitelist_item *wh; |
| 482 | |
| 483 | dev_t device = inode->i_rdev; |
| 484 | if (!device) |
| 485 | return 0; |
| 486 | if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode)) |
| 487 | return 0; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 488 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 489 | rcu_read_lock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 490 | |
| 491 | dev_cgroup = task_devcgroup(current); |
| 492 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 493 | list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 494 | if (wh->type & DEV_ALL) |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 495 | goto found; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 496 | if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode)) |
| 497 | continue; |
| 498 | if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode)) |
| 499 | continue; |
| 500 | if (wh->major != ~0 && wh->major != imajor(inode)) |
| 501 | continue; |
| 502 | if (wh->minor != ~0 && wh->minor != iminor(inode)) |
| 503 | continue; |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 504 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 505 | if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE)) |
| 506 | continue; |
| 507 | if ((mask & MAY_READ) && !(wh->access & ACC_READ)) |
| 508 | continue; |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 509 | found: |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 510 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 511 | return 0; |
| 512 | } |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 513 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 514 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 515 | |
| 516 | return -EPERM; |
| 517 | } |
| 518 | |
| 519 | int devcgroup_inode_mknod(int mode, dev_t dev) |
| 520 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 521 | struct dev_cgroup *dev_cgroup; |
| 522 | struct dev_whitelist_item *wh; |
| 523 | |
Serge E. Hallyn | 0b82ac3 | 2009-01-07 18:07:46 -0800 | [diff] [blame] | 524 | if (!S_ISBLK(mode) && !S_ISCHR(mode)) |
| 525 | return 0; |
| 526 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 527 | rcu_read_lock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 528 | |
| 529 | dev_cgroup = task_devcgroup(current); |
| 530 | |
Lai Jiangshan | 116e057 | 2009-01-07 18:07:45 -0800 | [diff] [blame] | 531 | list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 532 | if (wh->type & DEV_ALL) |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 533 | goto found; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 534 | if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode)) |
| 535 | continue; |
| 536 | if ((wh->type & DEV_CHAR) && !S_ISCHR(mode)) |
| 537 | continue; |
| 538 | if (wh->major != ~0 && wh->major != MAJOR(dev)) |
| 539 | continue; |
| 540 | if (wh->minor != ~0 && wh->minor != MINOR(dev)) |
| 541 | continue; |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 542 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 543 | if (!(wh->access & ACC_MKNOD)) |
| 544 | continue; |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 545 | found: |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 546 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 547 | return 0; |
| 548 | } |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 549 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 550 | rcu_read_unlock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 551 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 552 | return -EPERM; |
| 553 | } |