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; |
Aristeu Rozanski | 66b8ef6 | 2012-10-04 17:15:13 -0700 | [diff] [blame] | 45 | bool deny_all; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 46 | }; |
| 47 | |
Pavel Emelyanov | b66862f | 2008-06-05 22:46:24 -0700 | [diff] [blame] | 48 | static inline struct dev_cgroup *css_to_devcgroup(struct cgroup_subsys_state *s) |
| 49 | { |
| 50 | return container_of(s, struct dev_cgroup, css); |
| 51 | } |
| 52 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 53 | static inline struct dev_cgroup *cgroup_to_devcgroup(struct cgroup *cgroup) |
| 54 | { |
Pavel Emelyanov | b66862f | 2008-06-05 22:46:24 -0700 | [diff] [blame] | 55 | return css_to_devcgroup(cgroup_subsys_state(cgroup, devices_subsys_id)); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 56 | } |
| 57 | |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 58 | static inline struct dev_cgroup *task_devcgroup(struct task_struct *task) |
| 59 | { |
| 60 | return css_to_devcgroup(task_subsys_state(task, devices_subsys_id)); |
| 61 | } |
| 62 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 63 | struct cgroup_subsys devices_subsys; |
| 64 | |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 65 | static int devcgroup_can_attach(struct cgroup *new_cgrp, |
| 66 | struct cgroup_taskset *set) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 67 | { |
Tejun Heo | 2f7ee56 | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 68 | struct task_struct *task = cgroup_taskset_first(set); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 69 | |
Tejun Heo | 2f7ee56 | 2011-12-12 18:12:21 -0800 | [diff] [blame] | 70 | if (current != task && !capable(CAP_SYS_ADMIN)) |
| 71 | return -EPERM; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 72 | return 0; |
| 73 | } |
| 74 | |
| 75 | /* |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 76 | * called under devcgroup_mutex |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 77 | */ |
| 78 | static int dev_whitelist_copy(struct list_head *dest, struct list_head *orig) |
| 79 | { |
| 80 | struct dev_whitelist_item *wh, *tmp, *new; |
| 81 | |
| 82 | list_for_each_entry(wh, orig, list) { |
Li Zefan | 2cdc724 | 2008-10-18 20:28:06 -0700 | [diff] [blame] | 83 | new = kmemdup(wh, sizeof(*wh), GFP_KERNEL); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 84 | if (!new) |
| 85 | goto free_and_exit; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 86 | list_add_tail(&new->list, dest); |
| 87 | } |
| 88 | |
| 89 | return 0; |
| 90 | |
| 91 | free_and_exit: |
| 92 | list_for_each_entry_safe(wh, tmp, dest, list) { |
| 93 | list_del(&wh->list); |
| 94 | kfree(wh); |
| 95 | } |
| 96 | return -ENOMEM; |
| 97 | } |
| 98 | |
| 99 | /* Stupid prototype - don't bother combining existing entries */ |
| 100 | /* |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 101 | * called under devcgroup_mutex |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 102 | */ |
| 103 | static int dev_whitelist_add(struct dev_cgroup *dev_cgroup, |
| 104 | struct dev_whitelist_item *wh) |
| 105 | { |
Pavel Emelyanov | d1ee297 | 2008-06-05 22:46:28 -0700 | [diff] [blame] | 106 | struct dev_whitelist_item *whcopy, *walk; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 107 | |
Li Zefan | 2cdc724 | 2008-10-18 20:28:06 -0700 | [diff] [blame] | 108 | whcopy = kmemdup(wh, sizeof(*wh), GFP_KERNEL); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 109 | if (!whcopy) |
| 110 | return -ENOMEM; |
| 111 | |
Pavel Emelyanov | d1ee297 | 2008-06-05 22:46:28 -0700 | [diff] [blame] | 112 | list_for_each_entry(walk, &dev_cgroup->whitelist, list) { |
| 113 | if (walk->type != wh->type) |
| 114 | continue; |
| 115 | if (walk->major != wh->major) |
| 116 | continue; |
| 117 | if (walk->minor != wh->minor) |
| 118 | continue; |
| 119 | |
| 120 | walk->access |= wh->access; |
| 121 | kfree(whcopy); |
| 122 | whcopy = NULL; |
| 123 | } |
| 124 | |
| 125 | if (whcopy != NULL) |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 126 | list_add_tail_rcu(&whcopy->list, &dev_cgroup->whitelist); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 127 | return 0; |
| 128 | } |
| 129 | |
| 130 | /* |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 131 | * called under devcgroup_mutex |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 132 | */ |
| 133 | static void dev_whitelist_rm(struct dev_cgroup *dev_cgroup, |
| 134 | struct dev_whitelist_item *wh) |
| 135 | { |
| 136 | struct dev_whitelist_item *walk, *tmp; |
| 137 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 138 | list_for_each_entry_safe(walk, tmp, &dev_cgroup->whitelist, list) { |
| 139 | if (walk->type == DEV_ALL) |
| 140 | goto remove; |
| 141 | if (walk->type != wh->type) |
| 142 | continue; |
| 143 | if (walk->major != ~0 && walk->major != wh->major) |
| 144 | continue; |
| 145 | if (walk->minor != ~0 && walk->minor != wh->minor) |
| 146 | continue; |
| 147 | |
| 148 | remove: |
| 149 | walk->access &= ~wh->access; |
| 150 | if (!walk->access) { |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 151 | list_del_rcu(&walk->list); |
Lai Jiangshan | 6034f7e | 2011-03-15 18:07:57 +0800 | [diff] [blame] | 152 | kfree_rcu(walk, rcu); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 153 | } |
| 154 | } |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 155 | } |
| 156 | |
Aristeu Rozanski | 868539a | 2012-10-04 17:15:15 -0700 | [diff] [blame^] | 157 | /** |
| 158 | * dev_whitelist_clean - frees all entries of the whitelist |
| 159 | * @dev_cgroup: dev_cgroup with the whitelist to be cleaned |
| 160 | * |
| 161 | * called under devcgroup_mutex |
| 162 | */ |
| 163 | static void dev_whitelist_clean(struct dev_cgroup *dev_cgroup) |
| 164 | { |
| 165 | struct dev_whitelist_item *wh, *tmp; |
| 166 | |
| 167 | list_for_each_entry_safe(wh, tmp, &dev_cgroup->whitelist, list) { |
| 168 | list_del(&wh->list); |
| 169 | kfree(wh); |
| 170 | } |
| 171 | } |
| 172 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 173 | /* |
| 174 | * called from kernel/cgroup.c with cgroup_lock() held. |
| 175 | */ |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 176 | static struct cgroup_subsys_state *devcgroup_create(struct cgroup *cgroup) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 177 | { |
| 178 | struct dev_cgroup *dev_cgroup, *parent_dev_cgroup; |
| 179 | struct cgroup *parent_cgroup; |
| 180 | int ret; |
| 181 | |
| 182 | dev_cgroup = kzalloc(sizeof(*dev_cgroup), GFP_KERNEL); |
| 183 | if (!dev_cgroup) |
| 184 | return ERR_PTR(-ENOMEM); |
| 185 | INIT_LIST_HEAD(&dev_cgroup->whitelist); |
| 186 | parent_cgroup = cgroup->parent; |
| 187 | |
| 188 | if (parent_cgroup == NULL) { |
| 189 | struct dev_whitelist_item *wh; |
| 190 | wh = kmalloc(sizeof(*wh), GFP_KERNEL); |
| 191 | if (!wh) { |
| 192 | kfree(dev_cgroup); |
| 193 | return ERR_PTR(-ENOMEM); |
| 194 | } |
| 195 | wh->minor = wh->major = ~0; |
| 196 | wh->type = DEV_ALL; |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 197 | wh->access = ACC_MASK; |
Aristeu Rozanski | 66b8ef6 | 2012-10-04 17:15:13 -0700 | [diff] [blame] | 198 | dev_cgroup->deny_all = false; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 199 | list_add(&wh->list, &dev_cgroup->whitelist); |
| 200 | } else { |
| 201 | parent_dev_cgroup = cgroup_to_devcgroup(parent_cgroup); |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 202 | mutex_lock(&devcgroup_mutex); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 203 | ret = dev_whitelist_copy(&dev_cgroup->whitelist, |
| 204 | &parent_dev_cgroup->whitelist); |
Aristeu Rozanski | 66b8ef6 | 2012-10-04 17:15:13 -0700 | [diff] [blame] | 205 | dev_cgroup->deny_all = parent_dev_cgroup->deny_all; |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 206 | mutex_unlock(&devcgroup_mutex); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 207 | if (ret) { |
| 208 | kfree(dev_cgroup); |
| 209 | return ERR_PTR(ret); |
| 210 | } |
| 211 | } |
| 212 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 213 | return &dev_cgroup->css; |
| 214 | } |
| 215 | |
Li Zefan | 761b3ef | 2012-01-31 13:47:36 +0800 | [diff] [blame] | 216 | static void devcgroup_destroy(struct cgroup *cgroup) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 217 | { |
| 218 | struct dev_cgroup *dev_cgroup; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 219 | |
| 220 | dev_cgroup = cgroup_to_devcgroup(cgroup); |
Aristeu Rozanski | 868539a | 2012-10-04 17:15:15 -0700 | [diff] [blame^] | 221 | dev_whitelist_clean(dev_cgroup); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 222 | kfree(dev_cgroup); |
| 223 | } |
| 224 | |
| 225 | #define DEVCG_ALLOW 1 |
| 226 | #define DEVCG_DENY 2 |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 227 | #define DEVCG_LIST 3 |
| 228 | |
Li Zefan | 17d213f | 2008-07-13 12:14:02 -0700 | [diff] [blame] | 229 | #define MAJMINLEN 13 |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 230 | #define ACCLEN 4 |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 231 | |
| 232 | static void set_access(char *acc, short access) |
| 233 | { |
| 234 | int idx = 0; |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 235 | memset(acc, 0, ACCLEN); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 236 | if (access & ACC_READ) |
| 237 | acc[idx++] = 'r'; |
| 238 | if (access & ACC_WRITE) |
| 239 | acc[idx++] = 'w'; |
| 240 | if (access & ACC_MKNOD) |
| 241 | acc[idx++] = 'm'; |
| 242 | } |
| 243 | |
| 244 | static char type_to_char(short type) |
| 245 | { |
| 246 | if (type == DEV_ALL) |
| 247 | return 'a'; |
| 248 | if (type == DEV_CHAR) |
| 249 | return 'c'; |
| 250 | if (type == DEV_BLOCK) |
| 251 | return 'b'; |
| 252 | return 'X'; |
| 253 | } |
| 254 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 255 | static void set_majmin(char *str, unsigned m) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 256 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 257 | if (m == ~0) |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 258 | strcpy(str, "*"); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 259 | else |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 260 | sprintf(str, "%u", m); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 261 | } |
| 262 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 263 | static int devcgroup_seq_read(struct cgroup *cgroup, struct cftype *cft, |
| 264 | struct seq_file *m) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 265 | { |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 266 | struct dev_cgroup *devcgroup = cgroup_to_devcgroup(cgroup); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 267 | struct dev_whitelist_item *wh; |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 268 | char maj[MAJMINLEN], min[MAJMINLEN], acc[ACCLEN]; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 269 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 270 | rcu_read_lock(); |
| 271 | list_for_each_entry_rcu(wh, &devcgroup->whitelist, list) { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 272 | set_access(acc, wh->access); |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 273 | set_majmin(maj, wh->major); |
| 274 | set_majmin(min, wh->minor); |
| 275 | seq_printf(m, "%c %s:%s %s\n", type_to_char(wh->type), |
| 276 | maj, min, acc); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 277 | } |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 278 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 279 | |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 280 | return 0; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 281 | } |
| 282 | |
| 283 | /* |
| 284 | * may_access_whitelist: |
| 285 | * does the access granted to dev_cgroup c contain the access |
| 286 | * requested in whitelist item refwh. |
| 287 | * return 1 if yes, 0 if no. |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 288 | * call with devcgroup_mutex held |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 289 | */ |
| 290 | static int may_access_whitelist(struct dev_cgroup *c, |
| 291 | struct dev_whitelist_item *refwh) |
| 292 | { |
| 293 | struct dev_whitelist_item *whitem; |
| 294 | |
| 295 | list_for_each_entry(whitem, &c->whitelist, list) { |
| 296 | if (whitem->type & DEV_ALL) |
| 297 | return 1; |
| 298 | if ((refwh->type & DEV_BLOCK) && !(whitem->type & DEV_BLOCK)) |
| 299 | continue; |
| 300 | if ((refwh->type & DEV_CHAR) && !(whitem->type & DEV_CHAR)) |
| 301 | continue; |
| 302 | if (whitem->major != ~0 && whitem->major != refwh->major) |
| 303 | continue; |
| 304 | if (whitem->minor != ~0 && whitem->minor != refwh->minor) |
| 305 | continue; |
Li Zefan | ec229e8 | 2008-07-13 12:14:04 -0700 | [diff] [blame] | 306 | if (refwh->access & (~whitem->access)) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 307 | continue; |
| 308 | return 1; |
| 309 | } |
| 310 | return 0; |
| 311 | } |
| 312 | |
| 313 | /* |
| 314 | * parent_has_perm: |
| 315 | * when adding a new allow rule to a device whitelist, the rule |
| 316 | * must be allowed in the parent device |
| 317 | */ |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 318 | static int parent_has_perm(struct dev_cgroup *childcg, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 319 | struct dev_whitelist_item *wh) |
| 320 | { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 321 | struct cgroup *pcg = childcg->css.cgroup->parent; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 322 | struct dev_cgroup *parent; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 323 | |
| 324 | if (!pcg) |
| 325 | return 1; |
| 326 | parent = cgroup_to_devcgroup(pcg); |
Lai Jiangshan | 47c5980 | 2008-10-18 20:28:07 -0700 | [diff] [blame] | 327 | return may_access_whitelist(parent, wh); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 328 | } |
| 329 | |
| 330 | /* |
| 331 | * Modify the whitelist using allow/deny rules. |
| 332 | * CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD |
| 333 | * so we can give a container CAP_MKNOD to let it create devices but not |
| 334 | * modify the whitelist. |
| 335 | * It seems likely we'll want to add a CAP_CONTAINER capability to allow |
| 336 | * us to also grant CAP_SYS_ADMIN to containers without giving away the |
| 337 | * device whitelist controls, but for now we'll stick with CAP_SYS_ADMIN |
| 338 | * |
| 339 | * Taking rules away is always allowed (given CAP_SYS_ADMIN). Granting |
| 340 | * new access is only allowed if you're in the top-level cgroup, or your |
| 341 | * parent cgroup has the access you're asking for. |
| 342 | */ |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 343 | static int devcgroup_update_access(struct dev_cgroup *devcgroup, |
| 344 | int filetype, const char *buffer) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 345 | { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 346 | const char *b; |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 347 | char *endp; |
Li Zefan | c012a54 | 2008-10-18 20:28:07 -0700 | [diff] [blame] | 348 | int count; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 349 | struct dev_whitelist_item wh; |
| 350 | |
| 351 | if (!capable(CAP_SYS_ADMIN)) |
| 352 | return -EPERM; |
| 353 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 354 | memset(&wh, 0, sizeof(wh)); |
| 355 | b = buffer; |
| 356 | |
| 357 | switch (*b) { |
| 358 | case 'a': |
| 359 | wh.type = DEV_ALL; |
| 360 | wh.access = ACC_MASK; |
Li Zefan | d823f6b | 2008-07-04 10:00:07 -0700 | [diff] [blame] | 361 | wh.major = ~0; |
| 362 | wh.minor = ~0; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 363 | goto handle; |
| 364 | case 'b': |
| 365 | wh.type = DEV_BLOCK; |
| 366 | break; |
| 367 | case 'c': |
| 368 | wh.type = DEV_CHAR; |
| 369 | break; |
| 370 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 371 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 372 | } |
| 373 | b++; |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 374 | if (!isspace(*b)) |
| 375 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 376 | b++; |
| 377 | if (*b == '*') { |
| 378 | wh.major = ~0; |
| 379 | b++; |
| 380 | } else if (isdigit(*b)) { |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 381 | wh.major = simple_strtoul(b, &endp, 10); |
| 382 | b = endp; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 383 | } else { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 384 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 385 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 386 | if (*b != ':') |
| 387 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 388 | b++; |
| 389 | |
| 390 | /* read minor */ |
| 391 | if (*b == '*') { |
| 392 | wh.minor = ~0; |
| 393 | b++; |
| 394 | } else if (isdigit(*b)) { |
Li Zefan | 7759fc9 | 2008-07-25 01:47:08 -0700 | [diff] [blame] | 395 | wh.minor = simple_strtoul(b, &endp, 10); |
| 396 | b = endp; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 397 | } else { |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 398 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 399 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 400 | if (!isspace(*b)) |
| 401 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 402 | for (b++, count = 0; count < 3; count++, b++) { |
| 403 | switch (*b) { |
| 404 | case 'r': |
| 405 | wh.access |= ACC_READ; |
| 406 | break; |
| 407 | case 'w': |
| 408 | wh.access |= ACC_WRITE; |
| 409 | break; |
| 410 | case 'm': |
| 411 | wh.access |= ACC_MKNOD; |
| 412 | break; |
| 413 | case '\n': |
| 414 | case '\0': |
| 415 | count = 3; |
| 416 | break; |
| 417 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 418 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 419 | } |
| 420 | } |
| 421 | |
| 422 | handle: |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 423 | switch (filetype) { |
| 424 | case DEVCG_ALLOW: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 425 | if (!parent_has_perm(devcgroup, &wh)) |
| 426 | return -EPERM; |
Aristeu Rozanski | 66b8ef6 | 2012-10-04 17:15:13 -0700 | [diff] [blame] | 427 | devcgroup->deny_all = false; |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 428 | return dev_whitelist_add(devcgroup, &wh); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 429 | case DEVCG_DENY: |
| 430 | dev_whitelist_rm(devcgroup, &wh); |
Aristeu Rozanski | 66b8ef6 | 2012-10-04 17:15:13 -0700 | [diff] [blame] | 431 | devcgroup->deny_all = true; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 432 | break; |
| 433 | default: |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 434 | return -EINVAL; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 435 | } |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 436 | return 0; |
| 437 | } |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 438 | |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 439 | static int devcgroup_access_write(struct cgroup *cgrp, struct cftype *cft, |
| 440 | const char *buffer) |
| 441 | { |
| 442 | int retval; |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 443 | |
| 444 | mutex_lock(&devcgroup_mutex); |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 445 | retval = devcgroup_update_access(cgroup_to_devcgroup(cgrp), |
| 446 | cft->private, buffer); |
Li Zefan | b4046f0 | 2009-04-02 16:57:32 -0700 | [diff] [blame] | 447 | mutex_unlock(&devcgroup_mutex); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 448 | return retval; |
| 449 | } |
| 450 | |
| 451 | static struct cftype dev_cgroup_files[] = { |
| 452 | { |
| 453 | .name = "allow", |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 454 | .write_string = devcgroup_access_write, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 455 | .private = DEVCG_ALLOW, |
| 456 | }, |
| 457 | { |
| 458 | .name = "deny", |
Paul Menage | f92523e | 2008-07-25 01:47:03 -0700 | [diff] [blame] | 459 | .write_string = devcgroup_access_write, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 460 | .private = DEVCG_DENY, |
| 461 | }, |
Serge E. Hallyn | 29486df | 2008-04-29 01:00:14 -0700 | [diff] [blame] | 462 | { |
| 463 | .name = "list", |
| 464 | .read_seq_string = devcgroup_seq_read, |
| 465 | .private = DEVCG_LIST, |
| 466 | }, |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 467 | { } /* terminate */ |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 468 | }; |
| 469 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 470 | struct cgroup_subsys devices_subsys = { |
| 471 | .name = "devices", |
| 472 | .can_attach = devcgroup_can_attach, |
| 473 | .create = devcgroup_create, |
Justin P. Mattock | c5b60b5 | 2010-04-21 00:02:11 -0700 | [diff] [blame] | 474 | .destroy = devcgroup_destroy, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 475 | .subsys_id = devices_subsys_id, |
Tejun Heo | 4baf6e3 | 2012-04-01 12:09:55 -0700 | [diff] [blame] | 476 | .base_cftypes = dev_cgroup_files, |
Tejun Heo | 8c7f6ed | 2012-09-13 12:20:58 -0700 | [diff] [blame] | 477 | |
| 478 | /* |
| 479 | * While devices cgroup has the rudimentary hierarchy support which |
| 480 | * checks the parent's restriction, it doesn't properly propagates |
| 481 | * config changes in ancestors to their descendents. A child |
| 482 | * should only be allowed to add more restrictions to the parent's |
| 483 | * configuration. Fix it and remove the following. |
| 484 | */ |
| 485 | .broken_hierarchy = true, |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 486 | }; |
| 487 | |
Al Viro | 482e0cd | 2011-06-19 13:01:04 -0400 | [diff] [blame] | 488 | int __devcgroup_inode_permission(struct inode *inode, int mask) |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 489 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 490 | struct dev_cgroup *dev_cgroup; |
| 491 | struct dev_whitelist_item *wh; |
| 492 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 493 | rcu_read_lock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 494 | |
| 495 | dev_cgroup = task_devcgroup(current); |
| 496 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 497 | list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 498 | if (wh->type & DEV_ALL) |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 499 | goto found; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 500 | if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode)) |
| 501 | continue; |
| 502 | if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode)) |
| 503 | continue; |
| 504 | if (wh->major != ~0 && wh->major != imajor(inode)) |
| 505 | continue; |
| 506 | if (wh->minor != ~0 && wh->minor != iminor(inode)) |
| 507 | continue; |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 508 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 509 | if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE)) |
| 510 | continue; |
| 511 | if ((mask & MAY_READ) && !(wh->access & ACC_READ)) |
| 512 | continue; |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 513 | found: |
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 | return 0; |
| 516 | } |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 517 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 518 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 519 | |
| 520 | return -EPERM; |
| 521 | } |
| 522 | |
| 523 | int devcgroup_inode_mknod(int mode, dev_t dev) |
| 524 | { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 525 | struct dev_cgroup *dev_cgroup; |
| 526 | struct dev_whitelist_item *wh; |
| 527 | |
Serge E. Hallyn | 0b82ac3 | 2009-01-07 18:07:46 -0800 | [diff] [blame] | 528 | if (!S_ISBLK(mode) && !S_ISCHR(mode)) |
| 529 | return 0; |
| 530 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 531 | rcu_read_lock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 532 | |
| 533 | dev_cgroup = task_devcgroup(current); |
| 534 | |
Lai Jiangshan | 116e057 | 2009-01-07 18:07:45 -0800 | [diff] [blame] | 535 | list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) { |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 536 | if (wh->type & DEV_ALL) |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 537 | goto found; |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 538 | if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode)) |
| 539 | continue; |
| 540 | if ((wh->type & DEV_CHAR) && !S_ISCHR(mode)) |
| 541 | continue; |
| 542 | if (wh->major != ~0 && wh->major != MAJOR(dev)) |
| 543 | continue; |
| 544 | if (wh->minor != ~0 && wh->minor != MINOR(dev)) |
| 545 | continue; |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 546 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 547 | if (!(wh->access & ACC_MKNOD)) |
| 548 | continue; |
Li Zefan | cd50081 | 2009-06-17 16:26:33 -0700 | [diff] [blame] | 549 | found: |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 550 | rcu_read_unlock(); |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 551 | return 0; |
| 552 | } |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 553 | |
Pavel Emelyanov | 4efd1a1 | 2008-07-25 01:47:07 -0700 | [diff] [blame] | 554 | rcu_read_unlock(); |
Li Zefan | 36fd71d | 2008-09-02 14:35:52 -0700 | [diff] [blame] | 555 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 556 | return -EPERM; |
| 557 | } |