Commit | Line | Data |
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7e84522c | 1 | // SPDX-License-Identifier: GPL-2.0 |
3ad20fe3 CB |
2 | |
3 | #include <linux/compiler_types.h> | |
4 | #include <linux/errno.h> | |
5 | #include <linux/fs.h> | |
6 | #include <linux/fsnotify.h> | |
7 | #include <linux/gfp.h> | |
8 | #include <linux/idr.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/ipc_namespace.h> | |
11 | #include <linux/kdev_t.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/list.h> | |
01b3f1fc | 14 | #include <linux/namei.h> |
3ad20fe3 CB |
15 | #include <linux/magic.h> |
16 | #include <linux/major.h> | |
17 | #include <linux/miscdevice.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/mutex.h> | |
20 | #include <linux/mount.h> | |
095cf502 | 21 | #include <linux/fs_parser.h> |
3ad20fe3 CB |
22 | #include <linux/radix-tree.h> |
23 | #include <linux/sched.h> | |
849d540d | 24 | #include <linux/seq_file.h> |
3ad20fe3 CB |
25 | #include <linux/slab.h> |
26 | #include <linux/spinlock_types.h> | |
27 | #include <linux/stddef.h> | |
28 | #include <linux/string.h> | |
29 | #include <linux/types.h> | |
30 | #include <linux/uaccess.h> | |
31 | #include <linux/user_namespace.h> | |
32 | #include <linux/xarray.h> | |
33 | #include <uapi/asm-generic/errno-base.h> | |
34 | #include <uapi/linux/android/binder.h> | |
c13295ad | 35 | #include <uapi/linux/android/binderfs.h> |
3ad20fe3 CB |
36 | |
37 | #include "binder_internal.h" | |
38 | ||
39 | #define FIRST_INODE 1 | |
40 | #define SECOND_INODE 2 | |
41 | #define INODE_OFFSET 3 | |
42 | #define INTSTRLEN 21 | |
43 | #define BINDERFS_MAX_MINOR (1U << MINORBITS) | |
36bdf3ca CB |
44 | /* Ensure that the initial ipc namespace always has devices available. */ |
45 | #define BINDERFS_MAX_MINOR_CAPPED (BINDERFS_MAX_MINOR - 4) | |
3ad20fe3 | 46 | |
3ad20fe3 CB |
47 | static dev_t binderfs_dev; |
48 | static DEFINE_MUTEX(binderfs_minors_mutex); | |
49 | static DEFINE_IDA(binderfs_minors); | |
50 | ||
095cf502 | 51 | enum binderfs_param { |
849d540d | 52 | Opt_max, |
f0083451 | 53 | Opt_stats_mode, |
849d540d CB |
54 | }; |
55 | ||
f0083451 | 56 | enum binderfs_stats_mode { |
095cf502 CB |
57 | binderfs_stats_mode_unset, |
58 | binderfs_stats_mode_global, | |
f0083451 HV |
59 | }; |
60 | ||
095cf502 CB |
61 | static const struct constant_table binderfs_param_stats[] = { |
62 | { "global", binderfs_stats_mode_global }, | |
63 | {} | |
849d540d CB |
64 | }; |
65 | ||
89320020 | 66 | static const struct fs_parameter_spec binderfs_fs_parameters[] = { |
095cf502 CB |
67 | fsparam_u32("max", Opt_max), |
68 | fsparam_enum("stats", Opt_stats_mode, binderfs_param_stats), | |
69 | {} | |
70 | }; | |
71 | ||
72 | static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb) | |
3ad20fe3 | 73 | { |
095cf502 | 74 | return sb->s_fs_info; |
3ad20fe3 CB |
75 | } |
76 | ||
77 | bool is_binderfs_device(const struct inode *inode) | |
78 | { | |
79 | if (inode->i_sb->s_magic == BINDERFS_SUPER_MAGIC) | |
80 | return true; | |
81 | ||
82 | return false; | |
83 | } | |
84 | ||
85 | /** | |
86 | * binderfs_binder_device_create - allocate inode from super block of a | |
87 | * binderfs mount | |
88 | * @ref_inode: inode from wich the super block will be taken | |
89 | * @userp: buffer to copy information about new device for userspace to | |
90 | * @req: struct binderfs_device as copied from userspace | |
91 | * | |
01b3f1fc | 92 | * This function allocates a new binder_device and reserves a new minor |
3ad20fe3 CB |
93 | * number for it. |
94 | * Minor numbers are limited and tracked globally in binderfs_minors. The | |
95 | * function will stash a struct binder_device for the specific binder | |
96 | * device in i_private of the inode. | |
97 | * It will go on to allocate a new inode from the super block of the | |
98 | * filesystem mount, stash a struct binder_device in its i_private field | |
99 | * and attach a dentry to that inode. | |
100 | * | |
101 | * Return: 0 on success, negative errno on failure | |
102 | */ | |
103 | static int binderfs_binder_device_create(struct inode *ref_inode, | |
104 | struct binderfs_device __user *userp, | |
105 | struct binderfs_device *req) | |
106 | { | |
107 | int minor, ret; | |
01b3f1fc | 108 | struct dentry *dentry, *root; |
3ad20fe3 | 109 | struct binder_device *device; |
3ad20fe3 | 110 | char *name = NULL; |
01b3f1fc | 111 | size_t name_len; |
3ad20fe3 CB |
112 | struct inode *inode = NULL; |
113 | struct super_block *sb = ref_inode->i_sb; | |
114 | struct binderfs_info *info = sb->s_fs_info; | |
7fefaadd | 115 | #if defined(CONFIG_IPC_NS) |
36bdf3ca | 116 | bool use_reserve = (info->ipc_ns == &init_ipc_ns); |
7fefaadd CB |
117 | #else |
118 | bool use_reserve = true; | |
119 | #endif | |
3ad20fe3 CB |
120 | |
121 | /* Reserve new minor number for the new device. */ | |
122 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 123 | if (++info->device_count <= info->mount_opts.max) |
36bdf3ca CB |
124 | minor = ida_alloc_max(&binderfs_minors, |
125 | use_reserve ? BINDERFS_MAX_MINOR : | |
126 | BINDERFS_MAX_MINOR_CAPPED, | |
849d540d CB |
127 | GFP_KERNEL); |
128 | else | |
129 | minor = -ENOSPC; | |
130 | if (minor < 0) { | |
131 | --info->device_count; | |
132 | mutex_unlock(&binderfs_minors_mutex); | |
3ad20fe3 | 133 | return minor; |
849d540d CB |
134 | } |
135 | mutex_unlock(&binderfs_minors_mutex); | |
3ad20fe3 CB |
136 | |
137 | ret = -ENOMEM; | |
138 | device = kzalloc(sizeof(*device), GFP_KERNEL); | |
139 | if (!device) | |
140 | goto err; | |
141 | ||
142 | inode = new_inode(sb); | |
143 | if (!inode) | |
144 | goto err; | |
145 | ||
146 | inode->i_ino = minor + INODE_OFFSET; | |
147 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
148 | init_special_inode(inode, S_IFCHR | 0600, | |
149 | MKDEV(MAJOR(binderfs_dev), minor)); | |
150 | inode->i_fop = &binder_fops; | |
151 | inode->i_uid = info->root_uid; | |
152 | inode->i_gid = info->root_gid; | |
153 | ||
01b3f1fc CB |
154 | req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */ |
155 | name_len = strlen(req->name); | |
156 | /* Make sure to include terminating NUL byte */ | |
157 | name = kmemdup(req->name, name_len + 1, GFP_KERNEL); | |
3ad20fe3 CB |
158 | if (!name) |
159 | goto err; | |
160 | ||
f0fe2c0f | 161 | refcount_set(&device->ref, 1); |
3ad20fe3 CB |
162 | device->binderfs_inode = inode; |
163 | device->context.binder_context_mgr_uid = INVALID_UID; | |
164 | device->context.name = name; | |
165 | device->miscdev.name = name; | |
166 | device->miscdev.minor = minor; | |
167 | mutex_init(&device->context.context_mgr_node_lock); | |
168 | ||
169 | req->major = MAJOR(binderfs_dev); | |
170 | req->minor = minor; | |
171 | ||
ca2864c6 | 172 | if (userp && copy_to_user(userp, req, sizeof(*req))) { |
3ad20fe3 CB |
173 | ret = -EFAULT; |
174 | goto err; | |
175 | } | |
176 | ||
177 | root = sb->s_root; | |
178 | inode_lock(d_inode(root)); | |
01b3f1fc CB |
179 | |
180 | /* look it up */ | |
181 | dentry = lookup_one_len(name, root, name_len); | |
182 | if (IS_ERR(dentry)) { | |
3ad20fe3 | 183 | inode_unlock(d_inode(root)); |
01b3f1fc | 184 | ret = PTR_ERR(dentry); |
3ad20fe3 CB |
185 | goto err; |
186 | } | |
187 | ||
01b3f1fc CB |
188 | if (d_really_is_positive(dentry)) { |
189 | /* already exists */ | |
190 | dput(dentry); | |
191 | inode_unlock(d_inode(root)); | |
192 | ret = -EEXIST; | |
193 | goto err; | |
3ad20fe3 CB |
194 | } |
195 | ||
196 | inode->i_private = device; | |
01684db9 | 197 | d_instantiate(dentry, inode); |
3ad20fe3 CB |
198 | fsnotify_create(root->d_inode, dentry); |
199 | inode_unlock(d_inode(root)); | |
200 | ||
201 | return 0; | |
202 | ||
203 | err: | |
204 | kfree(name); | |
205 | kfree(device); | |
206 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 207 | --info->device_count; |
3ad20fe3 CB |
208 | ida_free(&binderfs_minors, minor); |
209 | mutex_unlock(&binderfs_minors_mutex); | |
210 | iput(inode); | |
211 | ||
212 | return ret; | |
213 | } | |
214 | ||
215 | /** | |
216 | * binderfs_ctl_ioctl - handle binder device node allocation requests | |
217 | * | |
218 | * The request handler for the binder-control device. All requests operate on | |
219 | * the binderfs mount the binder-control device resides in: | |
220 | * - BINDER_CTL_ADD | |
221 | * Allocate a new binder device. | |
222 | * | |
223 | * Return: 0 on success, negative errno on failure | |
224 | */ | |
225 | static long binder_ctl_ioctl(struct file *file, unsigned int cmd, | |
226 | unsigned long arg) | |
227 | { | |
228 | int ret = -EINVAL; | |
229 | struct inode *inode = file_inode(file); | |
230 | struct binderfs_device __user *device = (struct binderfs_device __user *)arg; | |
231 | struct binderfs_device device_req; | |
232 | ||
233 | switch (cmd) { | |
234 | case BINDER_CTL_ADD: | |
235 | ret = copy_from_user(&device_req, device, sizeof(device_req)); | |
236 | if (ret) { | |
237 | ret = -EFAULT; | |
238 | break; | |
239 | } | |
240 | ||
241 | ret = binderfs_binder_device_create(inode, device, &device_req); | |
242 | break; | |
243 | default: | |
244 | break; | |
245 | } | |
246 | ||
247 | return ret; | |
248 | } | |
249 | ||
250 | static void binderfs_evict_inode(struct inode *inode) | |
251 | { | |
252 | struct binder_device *device = inode->i_private; | |
095cf502 | 253 | struct binderfs_info *info = BINDERFS_SB(inode->i_sb); |
3ad20fe3 CB |
254 | |
255 | clear_inode(inode); | |
256 | ||
0e13e452 | 257 | if (!S_ISCHR(inode->i_mode) || !device) |
3ad20fe3 CB |
258 | return; |
259 | ||
260 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 261 | --info->device_count; |
3ad20fe3 CB |
262 | ida_free(&binderfs_minors, device->miscdev.minor); |
263 | mutex_unlock(&binderfs_minors_mutex); | |
264 | ||
f0fe2c0f CB |
265 | if (refcount_dec_and_test(&device->ref)) { |
266 | kfree(device->context.name); | |
267 | kfree(device); | |
268 | } | |
3ad20fe3 CB |
269 | } |
270 | ||
095cf502 CB |
271 | static int binderfs_fs_context_parse_param(struct fs_context *fc, |
272 | struct fs_parameter *param) | |
849d540d | 273 | { |
095cf502 CB |
274 | int opt; |
275 | struct binderfs_mount_opts *ctx = fc->fs_private; | |
276 | struct fs_parse_result result; | |
f0083451 | 277 | |
095cf502 CB |
278 | opt = fs_parse(fc, binderfs_fs_parameters, param, &result); |
279 | if (opt < 0) | |
280 | return opt; | |
f0083451 | 281 | |
095cf502 CB |
282 | switch (opt) { |
283 | case Opt_max: | |
284 | if (result.uint_32 > BINDERFS_MAX_MINOR) | |
285 | return invalfc(fc, "Bad value for '%s'", param->key); | |
f0083451 | 286 | |
095cf502 CB |
287 | ctx->max = result.uint_32; |
288 | break; | |
289 | case Opt_stats_mode: | |
290 | if (!capable(CAP_SYS_ADMIN)) | |
291 | return -EPERM; | |
292 | ||
293 | ctx->stats_mode = result.uint_32; | |
294 | break; | |
295 | default: | |
296 | return invalfc(fc, "Unsupported parameter '%s'", param->key); | |
849d540d CB |
297 | } |
298 | ||
299 | return 0; | |
300 | } | |
301 | ||
095cf502 | 302 | static int binderfs_fs_context_reconfigure(struct fs_context *fc) |
849d540d | 303 | { |
095cf502 CB |
304 | struct binderfs_mount_opts *ctx = fc->fs_private; |
305 | struct binderfs_info *info = BINDERFS_SB(fc->root->d_sb); | |
f0083451 | 306 | |
095cf502 CB |
307 | if (info->mount_opts.stats_mode != ctx->stats_mode) |
308 | return invalfc(fc, "Binderfs stats mode cannot be changed during a remount"); | |
f0083451 | 309 | |
095cf502 CB |
310 | info->mount_opts.stats_mode = ctx->stats_mode; |
311 | info->mount_opts.max = ctx->max; | |
f0083451 | 312 | return 0; |
849d540d CB |
313 | } |
314 | ||
095cf502 | 315 | static int binderfs_show_options(struct seq_file *seq, struct dentry *root) |
849d540d | 316 | { |
095cf502 | 317 | struct binderfs_info *info = BINDERFS_SB(root->d_sb); |
849d540d | 318 | |
849d540d CB |
319 | if (info->mount_opts.max <= BINDERFS_MAX_MINOR) |
320 | seq_printf(seq, ",max=%d", info->mount_opts.max); | |
095cf502 CB |
321 | |
322 | switch (info->mount_opts.stats_mode) { | |
323 | case binderfs_stats_mode_unset: | |
324 | break; | |
325 | case binderfs_stats_mode_global: | |
f0083451 | 326 | seq_printf(seq, ",stats=global"); |
095cf502 CB |
327 | break; |
328 | } | |
849d540d CB |
329 | |
330 | return 0; | |
331 | } | |
332 | ||
095cf502 CB |
333 | static void binderfs_put_super(struct super_block *sb) |
334 | { | |
335 | struct binderfs_info *info = sb->s_fs_info; | |
336 | ||
337 | if (info && info->ipc_ns) | |
338 | put_ipc_ns(info->ipc_ns); | |
339 | ||
340 | kfree(info); | |
341 | sb->s_fs_info = NULL; | |
342 | } | |
343 | ||
3ad20fe3 | 344 | static const struct super_operations binderfs_super_ops = { |
849d540d | 345 | .evict_inode = binderfs_evict_inode, |
095cf502 | 346 | .show_options = binderfs_show_options, |
849d540d | 347 | .statfs = simple_statfs, |
095cf502 | 348 | .put_super = binderfs_put_super, |
3ad20fe3 CB |
349 | }; |
350 | ||
e98e6fa1 CB |
351 | static inline bool is_binderfs_control_device(const struct dentry *dentry) |
352 | { | |
353 | struct binderfs_info *info = dentry->d_sb->s_fs_info; | |
81195f96 | 354 | |
e98e6fa1 CB |
355 | return info->control_dentry == dentry; |
356 | } | |
357 | ||
549c7297 CB |
358 | static int binderfs_rename(struct user_namespace *mnt_userns, |
359 | struct inode *old_dir, struct dentry *old_dentry, | |
3ad20fe3 CB |
360 | struct inode *new_dir, struct dentry *new_dentry, |
361 | unsigned int flags) | |
362 | { | |
e98e6fa1 CB |
363 | if (is_binderfs_control_device(old_dentry) || |
364 | is_binderfs_control_device(new_dentry)) | |
3ad20fe3 CB |
365 | return -EPERM; |
366 | ||
549c7297 CB |
367 | return simple_rename(&init_user_ns, old_dir, old_dentry, new_dir, |
368 | new_dentry, flags); | |
3ad20fe3 CB |
369 | } |
370 | ||
371 | static int binderfs_unlink(struct inode *dir, struct dentry *dentry) | |
372 | { | |
e98e6fa1 | 373 | if (is_binderfs_control_device(dentry)) |
3ad20fe3 CB |
374 | return -EPERM; |
375 | ||
376 | return simple_unlink(dir, dentry); | |
377 | } | |
378 | ||
379 | static const struct file_operations binder_ctl_fops = { | |
380 | .owner = THIS_MODULE, | |
381 | .open = nonseekable_open, | |
382 | .unlocked_ioctl = binder_ctl_ioctl, | |
383 | .compat_ioctl = binder_ctl_ioctl, | |
384 | .llseek = noop_llseek, | |
385 | }; | |
386 | ||
387 | /** | |
388 | * binderfs_binder_ctl_create - create a new binder-control device | |
389 | * @sb: super block of the binderfs mount | |
390 | * | |
391 | * This function creates a new binder-control device node in the binderfs mount | |
392 | * referred to by @sb. | |
393 | * | |
394 | * Return: 0 on success, negative errno on failure | |
395 | */ | |
396 | static int binderfs_binder_ctl_create(struct super_block *sb) | |
397 | { | |
398 | int minor, ret; | |
399 | struct dentry *dentry; | |
400 | struct binder_device *device; | |
401 | struct inode *inode = NULL; | |
402 | struct dentry *root = sb->s_root; | |
403 | struct binderfs_info *info = sb->s_fs_info; | |
da8ddba5 CB |
404 | #if defined(CONFIG_IPC_NS) |
405 | bool use_reserve = (info->ipc_ns == &init_ipc_ns); | |
406 | #else | |
407 | bool use_reserve = true; | |
408 | #endif | |
3ad20fe3 CB |
409 | |
410 | device = kzalloc(sizeof(*device), GFP_KERNEL); | |
411 | if (!device) | |
412 | return -ENOMEM; | |
413 | ||
3ad20fe3 CB |
414 | /* If we have already created a binder-control node, return. */ |
415 | if (info->control_dentry) { | |
416 | ret = 0; | |
417 | goto out; | |
418 | } | |
419 | ||
420 | ret = -ENOMEM; | |
421 | inode = new_inode(sb); | |
422 | if (!inode) | |
423 | goto out; | |
424 | ||
425 | /* Reserve a new minor number for the new device. */ | |
426 | mutex_lock(&binderfs_minors_mutex); | |
da8ddba5 CB |
427 | minor = ida_alloc_max(&binderfs_minors, |
428 | use_reserve ? BINDERFS_MAX_MINOR : | |
429 | BINDERFS_MAX_MINOR_CAPPED, | |
430 | GFP_KERNEL); | |
3ad20fe3 CB |
431 | mutex_unlock(&binderfs_minors_mutex); |
432 | if (minor < 0) { | |
433 | ret = minor; | |
434 | goto out; | |
435 | } | |
436 | ||
437 | inode->i_ino = SECOND_INODE; | |
438 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
439 | init_special_inode(inode, S_IFCHR | 0600, | |
440 | MKDEV(MAJOR(binderfs_dev), minor)); | |
441 | inode->i_fop = &binder_ctl_fops; | |
442 | inode->i_uid = info->root_uid; | |
443 | inode->i_gid = info->root_gid; | |
444 | ||
211b64e4 | 445 | refcount_set(&device->ref, 1); |
3ad20fe3 CB |
446 | device->binderfs_inode = inode; |
447 | device->miscdev.minor = minor; | |
448 | ||
449 | dentry = d_alloc_name(root, "binder-control"); | |
450 | if (!dentry) | |
451 | goto out; | |
452 | ||
453 | inode->i_private = device; | |
454 | info->control_dentry = dentry; | |
455 | d_add(dentry, inode); | |
3ad20fe3 CB |
456 | |
457 | return 0; | |
458 | ||
459 | out: | |
3ad20fe3 CB |
460 | kfree(device); |
461 | iput(inode); | |
462 | ||
463 | return ret; | |
464 | } | |
465 | ||
466 | static const struct inode_operations binderfs_dir_inode_operations = { | |
467 | .lookup = simple_lookup, | |
468 | .rename = binderfs_rename, | |
469 | .unlink = binderfs_unlink, | |
470 | }; | |
471 | ||
0e13e452 HV |
472 | static struct inode *binderfs_make_inode(struct super_block *sb, int mode) |
473 | { | |
474 | struct inode *ret; | |
475 | ||
476 | ret = new_inode(sb); | |
477 | if (ret) { | |
478 | ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET); | |
479 | ret->i_mode = mode; | |
480 | ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); | |
481 | } | |
482 | return ret; | |
483 | } | |
484 | ||
485 | static struct dentry *binderfs_create_dentry(struct dentry *parent, | |
486 | const char *name) | |
487 | { | |
488 | struct dentry *dentry; | |
489 | ||
490 | dentry = lookup_one_len(name, parent, strlen(name)); | |
491 | if (IS_ERR(dentry)) | |
492 | return dentry; | |
493 | ||
494 | /* Return error if the file/dir already exists. */ | |
495 | if (d_really_is_positive(dentry)) { | |
496 | dput(dentry); | |
497 | return ERR_PTR(-EEXIST); | |
498 | } | |
499 | ||
500 | return dentry; | |
501 | } | |
502 | ||
4feb80fa HV |
503 | void binderfs_remove_file(struct dentry *dentry) |
504 | { | |
505 | struct inode *parent_inode; | |
506 | ||
507 | parent_inode = d_inode(dentry->d_parent); | |
508 | inode_lock(parent_inode); | |
509 | if (simple_positive(dentry)) { | |
510 | dget(dentry); | |
511 | simple_unlink(parent_inode, dentry); | |
512 | d_delete(dentry); | |
513 | dput(dentry); | |
514 | } | |
515 | inode_unlock(parent_inode); | |
516 | } | |
517 | ||
518 | struct dentry *binderfs_create_file(struct dentry *parent, const char *name, | |
519 | const struct file_operations *fops, | |
520 | void *data) | |
0e13e452 HV |
521 | { |
522 | struct dentry *dentry; | |
523 | struct inode *new_inode, *parent_inode; | |
524 | struct super_block *sb; | |
525 | ||
526 | parent_inode = d_inode(parent); | |
527 | inode_lock(parent_inode); | |
528 | ||
529 | dentry = binderfs_create_dentry(parent, name); | |
530 | if (IS_ERR(dentry)) | |
531 | goto out; | |
532 | ||
533 | sb = parent_inode->i_sb; | |
534 | new_inode = binderfs_make_inode(sb, S_IFREG | 0444); | |
535 | if (!new_inode) { | |
536 | dput(dentry); | |
537 | dentry = ERR_PTR(-ENOMEM); | |
538 | goto out; | |
539 | } | |
540 | ||
541 | new_inode->i_fop = fops; | |
542 | new_inode->i_private = data; | |
543 | d_instantiate(dentry, new_inode); | |
544 | fsnotify_create(parent_inode, dentry); | |
545 | ||
546 | out: | |
547 | inode_unlock(parent_inode); | |
548 | return dentry; | |
549 | } | |
550 | ||
551 | static struct dentry *binderfs_create_dir(struct dentry *parent, | |
552 | const char *name) | |
553 | { | |
554 | struct dentry *dentry; | |
555 | struct inode *new_inode, *parent_inode; | |
556 | struct super_block *sb; | |
557 | ||
558 | parent_inode = d_inode(parent); | |
559 | inode_lock(parent_inode); | |
560 | ||
561 | dentry = binderfs_create_dentry(parent, name); | |
562 | if (IS_ERR(dentry)) | |
563 | goto out; | |
564 | ||
565 | sb = parent_inode->i_sb; | |
566 | new_inode = binderfs_make_inode(sb, S_IFDIR | 0755); | |
567 | if (!new_inode) { | |
568 | dput(dentry); | |
569 | dentry = ERR_PTR(-ENOMEM); | |
570 | goto out; | |
571 | } | |
572 | ||
573 | new_inode->i_fop = &simple_dir_operations; | |
574 | new_inode->i_op = &simple_dir_inode_operations; | |
575 | ||
576 | set_nlink(new_inode, 2); | |
577 | d_instantiate(dentry, new_inode); | |
578 | inc_nlink(parent_inode); | |
579 | fsnotify_mkdir(parent_inode, dentry); | |
580 | ||
581 | out: | |
582 | inode_unlock(parent_inode); | |
583 | return dentry; | |
584 | } | |
585 | ||
586 | static int init_binder_logs(struct super_block *sb) | |
587 | { | |
4feb80fa HV |
588 | struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; |
589 | struct binderfs_info *info; | |
0e13e452 HV |
590 | int ret = 0; |
591 | ||
592 | binder_logs_root_dir = binderfs_create_dir(sb->s_root, | |
593 | "binder_logs"); | |
594 | if (IS_ERR(binder_logs_root_dir)) { | |
595 | ret = PTR_ERR(binder_logs_root_dir); | |
596 | goto out; | |
597 | } | |
598 | ||
599 | dentry = binderfs_create_file(binder_logs_root_dir, "stats", | |
600 | &binder_stats_fops, NULL); | |
601 | if (IS_ERR(dentry)) { | |
602 | ret = PTR_ERR(dentry); | |
603 | goto out; | |
604 | } | |
605 | ||
606 | dentry = binderfs_create_file(binder_logs_root_dir, "state", | |
607 | &binder_state_fops, NULL); | |
608 | if (IS_ERR(dentry)) { | |
609 | ret = PTR_ERR(dentry); | |
610 | goto out; | |
611 | } | |
612 | ||
613 | dentry = binderfs_create_file(binder_logs_root_dir, "transactions", | |
614 | &binder_transactions_fops, NULL); | |
03e2e07e HV |
615 | if (IS_ERR(dentry)) { |
616 | ret = PTR_ERR(dentry); | |
617 | goto out; | |
618 | } | |
619 | ||
620 | dentry = binderfs_create_file(binder_logs_root_dir, | |
621 | "transaction_log", | |
622 | &binder_transaction_log_fops, | |
623 | &binder_transaction_log); | |
624 | if (IS_ERR(dentry)) { | |
625 | ret = PTR_ERR(dentry); | |
626 | goto out; | |
627 | } | |
628 | ||
629 | dentry = binderfs_create_file(binder_logs_root_dir, | |
630 | "failed_transaction_log", | |
631 | &binder_transaction_log_fops, | |
632 | &binder_transaction_log_failed); | |
4feb80fa | 633 | if (IS_ERR(dentry)) { |
0e13e452 | 634 | ret = PTR_ERR(dentry); |
4feb80fa HV |
635 | goto out; |
636 | } | |
637 | ||
638 | proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); | |
639 | if (IS_ERR(proc_log_dir)) { | |
640 | ret = PTR_ERR(proc_log_dir); | |
641 | goto out; | |
642 | } | |
643 | info = sb->s_fs_info; | |
644 | info->proc_log_dir = proc_log_dir; | |
0e13e452 HV |
645 | |
646 | out: | |
647 | return ret; | |
648 | } | |
649 | ||
095cf502 | 650 | static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) |
3ad20fe3 | 651 | { |
36975fc3 | 652 | int ret; |
3ad20fe3 | 653 | struct binderfs_info *info; |
095cf502 | 654 | struct binderfs_mount_opts *ctx = fc->fs_private; |
3ad20fe3 | 655 | struct inode *inode = NULL; |
7a1c4f28 | 656 | struct binderfs_device device_info = {}; |
ca2864c6 HV |
657 | const char *name; |
658 | size_t len; | |
3ad20fe3 CB |
659 | |
660 | sb->s_blocksize = PAGE_SIZE; | |
661 | sb->s_blocksize_bits = PAGE_SHIFT; | |
662 | ||
663 | /* | |
664 | * The binderfs filesystem can be mounted by userns root in a | |
665 | * non-initial userns. By default such mounts have the SB_I_NODEV flag | |
666 | * set in s_iflags to prevent security issues where userns root can | |
667 | * just create random device nodes via mknod() since it owns the | |
668 | * filesystem mount. But binderfs does not allow to create any files | |
669 | * including devices nodes. The only way to create binder devices nodes | |
670 | * is through the binder-control device which userns root is explicitly | |
671 | * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both | |
672 | * necessary and safe. | |
673 | */ | |
674 | sb->s_iflags &= ~SB_I_NODEV; | |
675 | sb->s_iflags |= SB_I_NOEXEC; | |
676 | sb->s_magic = BINDERFS_SUPER_MAGIC; | |
677 | sb->s_op = &binderfs_super_ops; | |
678 | sb->s_time_gran = 1; | |
679 | ||
36975fc3 CB |
680 | sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); |
681 | if (!sb->s_fs_info) | |
682 | return -ENOMEM; | |
683 | info = sb->s_fs_info; | |
684 | ||
685 | info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
3ad20fe3 | 686 | |
3ad20fe3 CB |
687 | info->root_gid = make_kgid(sb->s_user_ns, 0); |
688 | if (!gid_valid(info->root_gid)) | |
689 | info->root_gid = GLOBAL_ROOT_GID; | |
690 | info->root_uid = make_kuid(sb->s_user_ns, 0); | |
691 | if (!uid_valid(info->root_uid)) | |
692 | info->root_uid = GLOBAL_ROOT_UID; | |
095cf502 CB |
693 | info->mount_opts.max = ctx->max; |
694 | info->mount_opts.stats_mode = ctx->stats_mode; | |
3ad20fe3 | 695 | |
3ad20fe3 CB |
696 | inode = new_inode(sb); |
697 | if (!inode) | |
36975fc3 | 698 | return -ENOMEM; |
3ad20fe3 CB |
699 | |
700 | inode->i_ino = FIRST_INODE; | |
701 | inode->i_fop = &simple_dir_operations; | |
702 | inode->i_mode = S_IFDIR | 0755; | |
703 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
704 | inode->i_op = &binderfs_dir_inode_operations; | |
705 | set_nlink(inode, 2); | |
706 | ||
707 | sb->s_root = d_make_root(inode); | |
708 | if (!sb->s_root) | |
36975fc3 | 709 | return -ENOMEM; |
3ad20fe3 | 710 | |
ca2864c6 HV |
711 | ret = binderfs_binder_ctl_create(sb); |
712 | if (ret) | |
713 | return ret; | |
714 | ||
715 | name = binder_devices_param; | |
716 | for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { | |
717 | strscpy(device_info.name, name, len + 1); | |
718 | ret = binderfs_binder_device_create(inode, NULL, &device_info); | |
719 | if (ret) | |
720 | return ret; | |
721 | name += len; | |
722 | if (*name == ',') | |
723 | name++; | |
724 | } | |
725 | ||
095cf502 | 726 | if (info->mount_opts.stats_mode == binderfs_stats_mode_global) |
0e13e452 HV |
727 | return init_binder_logs(sb); |
728 | ||
ca2864c6 | 729 | return 0; |
3ad20fe3 CB |
730 | } |
731 | ||
095cf502 | 732 | static int binderfs_fs_context_get_tree(struct fs_context *fc) |
3ad20fe3 | 733 | { |
095cf502 | 734 | return get_tree_nodev(fc, binderfs_fill_super); |
3ad20fe3 CB |
735 | } |
736 | ||
095cf502 | 737 | static void binderfs_fs_context_free(struct fs_context *fc) |
3ad20fe3 | 738 | { |
095cf502 | 739 | struct binderfs_mount_opts *ctx = fc->fs_private; |
3ad20fe3 | 740 | |
095cf502 CB |
741 | kfree(ctx); |
742 | } | |
41984795 | 743 | |
095cf502 CB |
744 | static const struct fs_context_operations binderfs_fs_context_ops = { |
745 | .free = binderfs_fs_context_free, | |
746 | .get_tree = binderfs_fs_context_get_tree, | |
747 | .parse_param = binderfs_fs_context_parse_param, | |
748 | .reconfigure = binderfs_fs_context_reconfigure, | |
749 | }; | |
3ad20fe3 | 750 | |
095cf502 CB |
751 | static int binderfs_init_fs_context(struct fs_context *fc) |
752 | { | |
9e306ba3 | 753 | struct binderfs_mount_opts *ctx; |
095cf502 CB |
754 | |
755 | ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL); | |
756 | if (!ctx) | |
757 | return -ENOMEM; | |
758 | ||
759 | ctx->max = BINDERFS_MAX_MINOR; | |
760 | ctx->stats_mode = binderfs_stats_mode_unset; | |
761 | ||
762 | fc->fs_private = ctx; | |
763 | fc->ops = &binderfs_fs_context_ops; | |
764 | ||
765 | return 0; | |
3ad20fe3 CB |
766 | } |
767 | ||
768 | static struct file_system_type binder_fs_type = { | |
095cf502 CB |
769 | .name = "binder", |
770 | .init_fs_context = binderfs_init_fs_context, | |
771 | .parameters = binderfs_fs_parameters, | |
772 | .kill_sb = kill_litter_super, | |
773 | .fs_flags = FS_USERNS_MOUNT, | |
3ad20fe3 CB |
774 | }; |
775 | ||
5b9633af | 776 | int __init init_binderfs(void) |
3ad20fe3 CB |
777 | { |
778 | int ret; | |
028fb582 HV |
779 | const char *name; |
780 | size_t len; | |
781 | ||
782 | /* Verify that the default binderfs device names are valid. */ | |
783 | name = binder_devices_param; | |
784 | for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { | |
785 | if (len > BINDERFS_MAX_NAME) | |
786 | return -E2BIG; | |
787 | name += len; | |
788 | if (*name == ',') | |
789 | name++; | |
790 | } | |
3ad20fe3 CB |
791 | |
792 | /* Allocate new major number for binderfs. */ | |
793 | ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, | |
794 | "binder"); | |
795 | if (ret) | |
796 | return ret; | |
797 | ||
798 | ret = register_filesystem(&binder_fs_type); | |
799 | if (ret) { | |
800 | unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); | |
801 | return ret; | |
802 | } | |
803 | ||
3ad20fe3 CB |
804 | return ret; |
805 | } |