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Commit | Line | Data |
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3ad20fe3 CB |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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 | ||
095cf502 CB |
66 | const struct fs_parameter_spec binderfs_fs_parameters[] = { |
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; | |
354 | return info->control_dentry == dentry; | |
355 | } | |
356 | ||
3ad20fe3 CB |
357 | static int binderfs_rename(struct inode *old_dir, struct dentry *old_dentry, |
358 | struct inode *new_dir, struct dentry *new_dentry, | |
359 | unsigned int flags) | |
360 | { | |
e98e6fa1 CB |
361 | if (is_binderfs_control_device(old_dentry) || |
362 | is_binderfs_control_device(new_dentry)) | |
3ad20fe3 CB |
363 | return -EPERM; |
364 | ||
e98e6fa1 | 365 | return simple_rename(old_dir, old_dentry, new_dir, new_dentry, flags); |
3ad20fe3 CB |
366 | } |
367 | ||
368 | static int binderfs_unlink(struct inode *dir, struct dentry *dentry) | |
369 | { | |
e98e6fa1 | 370 | if (is_binderfs_control_device(dentry)) |
3ad20fe3 CB |
371 | return -EPERM; |
372 | ||
373 | return simple_unlink(dir, dentry); | |
374 | } | |
375 | ||
376 | static const struct file_operations binder_ctl_fops = { | |
377 | .owner = THIS_MODULE, | |
378 | .open = nonseekable_open, | |
379 | .unlocked_ioctl = binder_ctl_ioctl, | |
380 | .compat_ioctl = binder_ctl_ioctl, | |
381 | .llseek = noop_llseek, | |
382 | }; | |
383 | ||
384 | /** | |
385 | * binderfs_binder_ctl_create - create a new binder-control device | |
386 | * @sb: super block of the binderfs mount | |
387 | * | |
388 | * This function creates a new binder-control device node in the binderfs mount | |
389 | * referred to by @sb. | |
390 | * | |
391 | * Return: 0 on success, negative errno on failure | |
392 | */ | |
393 | static int binderfs_binder_ctl_create(struct super_block *sb) | |
394 | { | |
395 | int minor, ret; | |
396 | struct dentry *dentry; | |
397 | struct binder_device *device; | |
398 | struct inode *inode = NULL; | |
399 | struct dentry *root = sb->s_root; | |
400 | struct binderfs_info *info = sb->s_fs_info; | |
da8ddba5 CB |
401 | #if defined(CONFIG_IPC_NS) |
402 | bool use_reserve = (info->ipc_ns == &init_ipc_ns); | |
403 | #else | |
404 | bool use_reserve = true; | |
405 | #endif | |
3ad20fe3 CB |
406 | |
407 | device = kzalloc(sizeof(*device), GFP_KERNEL); | |
408 | if (!device) | |
409 | return -ENOMEM; | |
410 | ||
3ad20fe3 CB |
411 | /* If we have already created a binder-control node, return. */ |
412 | if (info->control_dentry) { | |
413 | ret = 0; | |
414 | goto out; | |
415 | } | |
416 | ||
417 | ret = -ENOMEM; | |
418 | inode = new_inode(sb); | |
419 | if (!inode) | |
420 | goto out; | |
421 | ||
422 | /* Reserve a new minor number for the new device. */ | |
423 | mutex_lock(&binderfs_minors_mutex); | |
da8ddba5 CB |
424 | minor = ida_alloc_max(&binderfs_minors, |
425 | use_reserve ? BINDERFS_MAX_MINOR : | |
426 | BINDERFS_MAX_MINOR_CAPPED, | |
427 | GFP_KERNEL); | |
3ad20fe3 CB |
428 | mutex_unlock(&binderfs_minors_mutex); |
429 | if (minor < 0) { | |
430 | ret = minor; | |
431 | goto out; | |
432 | } | |
433 | ||
434 | inode->i_ino = SECOND_INODE; | |
435 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
436 | init_special_inode(inode, S_IFCHR | 0600, | |
437 | MKDEV(MAJOR(binderfs_dev), minor)); | |
438 | inode->i_fop = &binder_ctl_fops; | |
439 | inode->i_uid = info->root_uid; | |
440 | inode->i_gid = info->root_gid; | |
441 | ||
211b64e4 | 442 | refcount_set(&device->ref, 1); |
3ad20fe3 CB |
443 | device->binderfs_inode = inode; |
444 | device->miscdev.minor = minor; | |
445 | ||
446 | dentry = d_alloc_name(root, "binder-control"); | |
447 | if (!dentry) | |
448 | goto out; | |
449 | ||
450 | inode->i_private = device; | |
451 | info->control_dentry = dentry; | |
452 | d_add(dentry, inode); | |
3ad20fe3 CB |
453 | |
454 | return 0; | |
455 | ||
456 | out: | |
3ad20fe3 CB |
457 | kfree(device); |
458 | iput(inode); | |
459 | ||
460 | return ret; | |
461 | } | |
462 | ||
463 | static const struct inode_operations binderfs_dir_inode_operations = { | |
464 | .lookup = simple_lookup, | |
465 | .rename = binderfs_rename, | |
466 | .unlink = binderfs_unlink, | |
467 | }; | |
468 | ||
0e13e452 HV |
469 | static struct inode *binderfs_make_inode(struct super_block *sb, int mode) |
470 | { | |
471 | struct inode *ret; | |
472 | ||
473 | ret = new_inode(sb); | |
474 | if (ret) { | |
475 | ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET); | |
476 | ret->i_mode = mode; | |
477 | ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); | |
478 | } | |
479 | return ret; | |
480 | } | |
481 | ||
482 | static struct dentry *binderfs_create_dentry(struct dentry *parent, | |
483 | const char *name) | |
484 | { | |
485 | struct dentry *dentry; | |
486 | ||
487 | dentry = lookup_one_len(name, parent, strlen(name)); | |
488 | if (IS_ERR(dentry)) | |
489 | return dentry; | |
490 | ||
491 | /* Return error if the file/dir already exists. */ | |
492 | if (d_really_is_positive(dentry)) { | |
493 | dput(dentry); | |
494 | return ERR_PTR(-EEXIST); | |
495 | } | |
496 | ||
497 | return dentry; | |
498 | } | |
499 | ||
4feb80fa HV |
500 | void binderfs_remove_file(struct dentry *dentry) |
501 | { | |
502 | struct inode *parent_inode; | |
503 | ||
504 | parent_inode = d_inode(dentry->d_parent); | |
505 | inode_lock(parent_inode); | |
506 | if (simple_positive(dentry)) { | |
507 | dget(dentry); | |
508 | simple_unlink(parent_inode, dentry); | |
509 | d_delete(dentry); | |
510 | dput(dentry); | |
511 | } | |
512 | inode_unlock(parent_inode); | |
513 | } | |
514 | ||
515 | struct dentry *binderfs_create_file(struct dentry *parent, const char *name, | |
516 | const struct file_operations *fops, | |
517 | void *data) | |
0e13e452 HV |
518 | { |
519 | struct dentry *dentry; | |
520 | struct inode *new_inode, *parent_inode; | |
521 | struct super_block *sb; | |
522 | ||
523 | parent_inode = d_inode(parent); | |
524 | inode_lock(parent_inode); | |
525 | ||
526 | dentry = binderfs_create_dentry(parent, name); | |
527 | if (IS_ERR(dentry)) | |
528 | goto out; | |
529 | ||
530 | sb = parent_inode->i_sb; | |
531 | new_inode = binderfs_make_inode(sb, S_IFREG | 0444); | |
532 | if (!new_inode) { | |
533 | dput(dentry); | |
534 | dentry = ERR_PTR(-ENOMEM); | |
535 | goto out; | |
536 | } | |
537 | ||
538 | new_inode->i_fop = fops; | |
539 | new_inode->i_private = data; | |
540 | d_instantiate(dentry, new_inode); | |
541 | fsnotify_create(parent_inode, dentry); | |
542 | ||
543 | out: | |
544 | inode_unlock(parent_inode); | |
545 | return dentry; | |
546 | } | |
547 | ||
548 | static struct dentry *binderfs_create_dir(struct dentry *parent, | |
549 | const char *name) | |
550 | { | |
551 | struct dentry *dentry; | |
552 | struct inode *new_inode, *parent_inode; | |
553 | struct super_block *sb; | |
554 | ||
555 | parent_inode = d_inode(parent); | |
556 | inode_lock(parent_inode); | |
557 | ||
558 | dentry = binderfs_create_dentry(parent, name); | |
559 | if (IS_ERR(dentry)) | |
560 | goto out; | |
561 | ||
562 | sb = parent_inode->i_sb; | |
563 | new_inode = binderfs_make_inode(sb, S_IFDIR | 0755); | |
564 | if (!new_inode) { | |
565 | dput(dentry); | |
566 | dentry = ERR_PTR(-ENOMEM); | |
567 | goto out; | |
568 | } | |
569 | ||
570 | new_inode->i_fop = &simple_dir_operations; | |
571 | new_inode->i_op = &simple_dir_inode_operations; | |
572 | ||
573 | set_nlink(new_inode, 2); | |
574 | d_instantiate(dentry, new_inode); | |
575 | inc_nlink(parent_inode); | |
576 | fsnotify_mkdir(parent_inode, dentry); | |
577 | ||
578 | out: | |
579 | inode_unlock(parent_inode); | |
580 | return dentry; | |
581 | } | |
582 | ||
583 | static int init_binder_logs(struct super_block *sb) | |
584 | { | |
4feb80fa HV |
585 | struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; |
586 | struct binderfs_info *info; | |
0e13e452 HV |
587 | int ret = 0; |
588 | ||
589 | binder_logs_root_dir = binderfs_create_dir(sb->s_root, | |
590 | "binder_logs"); | |
591 | if (IS_ERR(binder_logs_root_dir)) { | |
592 | ret = PTR_ERR(binder_logs_root_dir); | |
593 | goto out; | |
594 | } | |
595 | ||
596 | dentry = binderfs_create_file(binder_logs_root_dir, "stats", | |
597 | &binder_stats_fops, NULL); | |
598 | if (IS_ERR(dentry)) { | |
599 | ret = PTR_ERR(dentry); | |
600 | goto out; | |
601 | } | |
602 | ||
603 | dentry = binderfs_create_file(binder_logs_root_dir, "state", | |
604 | &binder_state_fops, NULL); | |
605 | if (IS_ERR(dentry)) { | |
606 | ret = PTR_ERR(dentry); | |
607 | goto out; | |
608 | } | |
609 | ||
610 | dentry = binderfs_create_file(binder_logs_root_dir, "transactions", | |
611 | &binder_transactions_fops, NULL); | |
03e2e07e HV |
612 | if (IS_ERR(dentry)) { |
613 | ret = PTR_ERR(dentry); | |
614 | goto out; | |
615 | } | |
616 | ||
617 | dentry = binderfs_create_file(binder_logs_root_dir, | |
618 | "transaction_log", | |
619 | &binder_transaction_log_fops, | |
620 | &binder_transaction_log); | |
621 | if (IS_ERR(dentry)) { | |
622 | ret = PTR_ERR(dentry); | |
623 | goto out; | |
624 | } | |
625 | ||
626 | dentry = binderfs_create_file(binder_logs_root_dir, | |
627 | "failed_transaction_log", | |
628 | &binder_transaction_log_fops, | |
629 | &binder_transaction_log_failed); | |
4feb80fa | 630 | if (IS_ERR(dentry)) { |
0e13e452 | 631 | ret = PTR_ERR(dentry); |
4feb80fa HV |
632 | goto out; |
633 | } | |
634 | ||
635 | proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); | |
636 | if (IS_ERR(proc_log_dir)) { | |
637 | ret = PTR_ERR(proc_log_dir); | |
638 | goto out; | |
639 | } | |
640 | info = sb->s_fs_info; | |
641 | info->proc_log_dir = proc_log_dir; | |
0e13e452 HV |
642 | |
643 | out: | |
644 | return ret; | |
645 | } | |
646 | ||
095cf502 | 647 | static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) |
3ad20fe3 | 648 | { |
36975fc3 | 649 | int ret; |
3ad20fe3 | 650 | struct binderfs_info *info; |
095cf502 | 651 | struct binderfs_mount_opts *ctx = fc->fs_private; |
3ad20fe3 | 652 | struct inode *inode = NULL; |
ca2864c6 HV |
653 | struct binderfs_device device_info = { 0 }; |
654 | const char *name; | |
655 | size_t len; | |
3ad20fe3 CB |
656 | |
657 | sb->s_blocksize = PAGE_SIZE; | |
658 | sb->s_blocksize_bits = PAGE_SHIFT; | |
659 | ||
660 | /* | |
661 | * The binderfs filesystem can be mounted by userns root in a | |
662 | * non-initial userns. By default such mounts have the SB_I_NODEV flag | |
663 | * set in s_iflags to prevent security issues where userns root can | |
664 | * just create random device nodes via mknod() since it owns the | |
665 | * filesystem mount. But binderfs does not allow to create any files | |
666 | * including devices nodes. The only way to create binder devices nodes | |
667 | * is through the binder-control device which userns root is explicitly | |
668 | * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both | |
669 | * necessary and safe. | |
670 | */ | |
671 | sb->s_iflags &= ~SB_I_NODEV; | |
672 | sb->s_iflags |= SB_I_NOEXEC; | |
673 | sb->s_magic = BINDERFS_SUPER_MAGIC; | |
674 | sb->s_op = &binderfs_super_ops; | |
675 | sb->s_time_gran = 1; | |
676 | ||
36975fc3 CB |
677 | sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); |
678 | if (!sb->s_fs_info) | |
679 | return -ENOMEM; | |
680 | info = sb->s_fs_info; | |
681 | ||
682 | info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
3ad20fe3 | 683 | |
3ad20fe3 CB |
684 | info->root_gid = make_kgid(sb->s_user_ns, 0); |
685 | if (!gid_valid(info->root_gid)) | |
686 | info->root_gid = GLOBAL_ROOT_GID; | |
687 | info->root_uid = make_kuid(sb->s_user_ns, 0); | |
688 | if (!uid_valid(info->root_uid)) | |
689 | info->root_uid = GLOBAL_ROOT_UID; | |
095cf502 CB |
690 | info->mount_opts.max = ctx->max; |
691 | info->mount_opts.stats_mode = ctx->stats_mode; | |
3ad20fe3 | 692 | |
3ad20fe3 CB |
693 | inode = new_inode(sb); |
694 | if (!inode) | |
36975fc3 | 695 | return -ENOMEM; |
3ad20fe3 CB |
696 | |
697 | inode->i_ino = FIRST_INODE; | |
698 | inode->i_fop = &simple_dir_operations; | |
699 | inode->i_mode = S_IFDIR | 0755; | |
700 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
701 | inode->i_op = &binderfs_dir_inode_operations; | |
702 | set_nlink(inode, 2); | |
703 | ||
704 | sb->s_root = d_make_root(inode); | |
705 | if (!sb->s_root) | |
36975fc3 | 706 | return -ENOMEM; |
3ad20fe3 | 707 | |
ca2864c6 HV |
708 | ret = binderfs_binder_ctl_create(sb); |
709 | if (ret) | |
710 | return ret; | |
711 | ||
712 | name = binder_devices_param; | |
713 | for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { | |
714 | strscpy(device_info.name, name, len + 1); | |
715 | ret = binderfs_binder_device_create(inode, NULL, &device_info); | |
716 | if (ret) | |
717 | return ret; | |
718 | name += len; | |
719 | if (*name == ',') | |
720 | name++; | |
721 | } | |
722 | ||
095cf502 | 723 | if (info->mount_opts.stats_mode == binderfs_stats_mode_global) |
0e13e452 HV |
724 | return init_binder_logs(sb); |
725 | ||
ca2864c6 | 726 | return 0; |
3ad20fe3 CB |
727 | } |
728 | ||
095cf502 | 729 | static int binderfs_fs_context_get_tree(struct fs_context *fc) |
3ad20fe3 | 730 | { |
095cf502 | 731 | return get_tree_nodev(fc, binderfs_fill_super); |
3ad20fe3 CB |
732 | } |
733 | ||
095cf502 | 734 | static void binderfs_fs_context_free(struct fs_context *fc) |
3ad20fe3 | 735 | { |
095cf502 | 736 | struct binderfs_mount_opts *ctx = fc->fs_private; |
3ad20fe3 | 737 | |
095cf502 CB |
738 | kfree(ctx); |
739 | } | |
41984795 | 740 | |
095cf502 CB |
741 | static const struct fs_context_operations binderfs_fs_context_ops = { |
742 | .free = binderfs_fs_context_free, | |
743 | .get_tree = binderfs_fs_context_get_tree, | |
744 | .parse_param = binderfs_fs_context_parse_param, | |
745 | .reconfigure = binderfs_fs_context_reconfigure, | |
746 | }; | |
3ad20fe3 | 747 | |
095cf502 CB |
748 | static int binderfs_init_fs_context(struct fs_context *fc) |
749 | { | |
750 | struct binderfs_mount_opts *ctx = fc->fs_private; | |
751 | ||
752 | ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL); | |
753 | if (!ctx) | |
754 | return -ENOMEM; | |
755 | ||
756 | ctx->max = BINDERFS_MAX_MINOR; | |
757 | ctx->stats_mode = binderfs_stats_mode_unset; | |
758 | ||
759 | fc->fs_private = ctx; | |
760 | fc->ops = &binderfs_fs_context_ops; | |
761 | ||
762 | return 0; | |
3ad20fe3 CB |
763 | } |
764 | ||
765 | static struct file_system_type binder_fs_type = { | |
095cf502 CB |
766 | .name = "binder", |
767 | .init_fs_context = binderfs_init_fs_context, | |
768 | .parameters = binderfs_fs_parameters, | |
769 | .kill_sb = kill_litter_super, | |
770 | .fs_flags = FS_USERNS_MOUNT, | |
3ad20fe3 CB |
771 | }; |
772 | ||
5b9633af | 773 | int __init init_binderfs(void) |
3ad20fe3 CB |
774 | { |
775 | int ret; | |
028fb582 HV |
776 | const char *name; |
777 | size_t len; | |
778 | ||
779 | /* Verify that the default binderfs device names are valid. */ | |
780 | name = binder_devices_param; | |
781 | for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { | |
782 | if (len > BINDERFS_MAX_NAME) | |
783 | return -E2BIG; | |
784 | name += len; | |
785 | if (*name == ',') | |
786 | name++; | |
787 | } | |
3ad20fe3 CB |
788 | |
789 | /* Allocate new major number for binderfs. */ | |
790 | ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, | |
791 | "binder"); | |
792 | if (ret) | |
793 | return ret; | |
794 | ||
795 | ret = register_filesystem(&binder_fs_type); | |
796 | if (ret) { | |
797 | unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); | |
798 | return ret; | |
799 | } | |
800 | ||
3ad20fe3 CB |
801 | return ret; |
802 | } |