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 | ||
fc470abf CL |
61 | struct binder_features { |
62 | bool oneway_spam_detection; | |
63 | }; | |
64 | ||
095cf502 CB |
65 | static const struct constant_table binderfs_param_stats[] = { |
66 | { "global", binderfs_stats_mode_global }, | |
67 | {} | |
849d540d CB |
68 | }; |
69 | ||
89320020 | 70 | static const struct fs_parameter_spec binderfs_fs_parameters[] = { |
095cf502 CB |
71 | fsparam_u32("max", Opt_max), |
72 | fsparam_enum("stats", Opt_stats_mode, binderfs_param_stats), | |
73 | {} | |
74 | }; | |
75 | ||
fc470abf CL |
76 | static struct binder_features binder_features = { |
77 | .oneway_spam_detection = true, | |
78 | }; | |
79 | ||
095cf502 | 80 | static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb) |
3ad20fe3 | 81 | { |
095cf502 | 82 | return sb->s_fs_info; |
3ad20fe3 CB |
83 | } |
84 | ||
85 | bool is_binderfs_device(const struct inode *inode) | |
86 | { | |
87 | if (inode->i_sb->s_magic == BINDERFS_SUPER_MAGIC) | |
88 | return true; | |
89 | ||
90 | return false; | |
91 | } | |
92 | ||
93 | /** | |
94 | * binderfs_binder_device_create - allocate inode from super block of a | |
95 | * binderfs mount | |
96 | * @ref_inode: inode from wich the super block will be taken | |
97 | * @userp: buffer to copy information about new device for userspace to | |
98 | * @req: struct binderfs_device as copied from userspace | |
99 | * | |
01b3f1fc | 100 | * This function allocates a new binder_device and reserves a new minor |
3ad20fe3 CB |
101 | * number for it. |
102 | * Minor numbers are limited and tracked globally in binderfs_minors. The | |
103 | * function will stash a struct binder_device for the specific binder | |
104 | * device in i_private of the inode. | |
105 | * It will go on to allocate a new inode from the super block of the | |
106 | * filesystem mount, stash a struct binder_device in its i_private field | |
107 | * and attach a dentry to that inode. | |
108 | * | |
109 | * Return: 0 on success, negative errno on failure | |
110 | */ | |
111 | static int binderfs_binder_device_create(struct inode *ref_inode, | |
112 | struct binderfs_device __user *userp, | |
113 | struct binderfs_device *req) | |
114 | { | |
115 | int minor, ret; | |
01b3f1fc | 116 | struct dentry *dentry, *root; |
3ad20fe3 | 117 | struct binder_device *device; |
3ad20fe3 | 118 | char *name = NULL; |
01b3f1fc | 119 | size_t name_len; |
3ad20fe3 CB |
120 | struct inode *inode = NULL; |
121 | struct super_block *sb = ref_inode->i_sb; | |
122 | struct binderfs_info *info = sb->s_fs_info; | |
7fefaadd | 123 | #if defined(CONFIG_IPC_NS) |
36bdf3ca | 124 | bool use_reserve = (info->ipc_ns == &init_ipc_ns); |
7fefaadd CB |
125 | #else |
126 | bool use_reserve = true; | |
127 | #endif | |
3ad20fe3 CB |
128 | |
129 | /* Reserve new minor number for the new device. */ | |
130 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 131 | if (++info->device_count <= info->mount_opts.max) |
36bdf3ca CB |
132 | minor = ida_alloc_max(&binderfs_minors, |
133 | use_reserve ? BINDERFS_MAX_MINOR : | |
134 | BINDERFS_MAX_MINOR_CAPPED, | |
849d540d CB |
135 | GFP_KERNEL); |
136 | else | |
137 | minor = -ENOSPC; | |
138 | if (minor < 0) { | |
139 | --info->device_count; | |
140 | mutex_unlock(&binderfs_minors_mutex); | |
3ad20fe3 | 141 | return minor; |
849d540d CB |
142 | } |
143 | mutex_unlock(&binderfs_minors_mutex); | |
3ad20fe3 CB |
144 | |
145 | ret = -ENOMEM; | |
146 | device = kzalloc(sizeof(*device), GFP_KERNEL); | |
147 | if (!device) | |
148 | goto err; | |
149 | ||
150 | inode = new_inode(sb); | |
151 | if (!inode) | |
152 | goto err; | |
153 | ||
154 | inode->i_ino = minor + INODE_OFFSET; | |
155 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
156 | init_special_inode(inode, S_IFCHR | 0600, | |
157 | MKDEV(MAJOR(binderfs_dev), minor)); | |
158 | inode->i_fop = &binder_fops; | |
159 | inode->i_uid = info->root_uid; | |
160 | inode->i_gid = info->root_gid; | |
161 | ||
01b3f1fc CB |
162 | req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */ |
163 | name_len = strlen(req->name); | |
164 | /* Make sure to include terminating NUL byte */ | |
165 | name = kmemdup(req->name, name_len + 1, GFP_KERNEL); | |
3ad20fe3 CB |
166 | if (!name) |
167 | goto err; | |
168 | ||
f0fe2c0f | 169 | refcount_set(&device->ref, 1); |
3ad20fe3 CB |
170 | device->binderfs_inode = inode; |
171 | device->context.binder_context_mgr_uid = INVALID_UID; | |
172 | device->context.name = name; | |
173 | device->miscdev.name = name; | |
174 | device->miscdev.minor = minor; | |
175 | mutex_init(&device->context.context_mgr_node_lock); | |
176 | ||
177 | req->major = MAJOR(binderfs_dev); | |
178 | req->minor = minor; | |
179 | ||
ca2864c6 | 180 | if (userp && copy_to_user(userp, req, sizeof(*req))) { |
3ad20fe3 CB |
181 | ret = -EFAULT; |
182 | goto err; | |
183 | } | |
184 | ||
185 | root = sb->s_root; | |
186 | inode_lock(d_inode(root)); | |
01b3f1fc CB |
187 | |
188 | /* look it up */ | |
189 | dentry = lookup_one_len(name, root, name_len); | |
190 | if (IS_ERR(dentry)) { | |
3ad20fe3 | 191 | inode_unlock(d_inode(root)); |
01b3f1fc | 192 | ret = PTR_ERR(dentry); |
3ad20fe3 CB |
193 | goto err; |
194 | } | |
195 | ||
01b3f1fc CB |
196 | if (d_really_is_positive(dentry)) { |
197 | /* already exists */ | |
198 | dput(dentry); | |
199 | inode_unlock(d_inode(root)); | |
200 | ret = -EEXIST; | |
201 | goto err; | |
3ad20fe3 CB |
202 | } |
203 | ||
204 | inode->i_private = device; | |
01684db9 | 205 | d_instantiate(dentry, inode); |
3ad20fe3 CB |
206 | fsnotify_create(root->d_inode, dentry); |
207 | inode_unlock(d_inode(root)); | |
208 | ||
209 | return 0; | |
210 | ||
211 | err: | |
212 | kfree(name); | |
213 | kfree(device); | |
214 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 215 | --info->device_count; |
3ad20fe3 CB |
216 | ida_free(&binderfs_minors, minor); |
217 | mutex_unlock(&binderfs_minors_mutex); | |
218 | iput(inode); | |
219 | ||
220 | return ret; | |
221 | } | |
222 | ||
223 | /** | |
224 | * binderfs_ctl_ioctl - handle binder device node allocation requests | |
225 | * | |
226 | * The request handler for the binder-control device. All requests operate on | |
227 | * the binderfs mount the binder-control device resides in: | |
228 | * - BINDER_CTL_ADD | |
229 | * Allocate a new binder device. | |
230 | * | |
231 | * Return: 0 on success, negative errno on failure | |
232 | */ | |
233 | static long binder_ctl_ioctl(struct file *file, unsigned int cmd, | |
234 | unsigned long arg) | |
235 | { | |
236 | int ret = -EINVAL; | |
237 | struct inode *inode = file_inode(file); | |
238 | struct binderfs_device __user *device = (struct binderfs_device __user *)arg; | |
239 | struct binderfs_device device_req; | |
240 | ||
241 | switch (cmd) { | |
242 | case BINDER_CTL_ADD: | |
243 | ret = copy_from_user(&device_req, device, sizeof(device_req)); | |
244 | if (ret) { | |
245 | ret = -EFAULT; | |
246 | break; | |
247 | } | |
248 | ||
249 | ret = binderfs_binder_device_create(inode, device, &device_req); | |
250 | break; | |
251 | default: | |
252 | break; | |
253 | } | |
254 | ||
255 | return ret; | |
256 | } | |
257 | ||
258 | static void binderfs_evict_inode(struct inode *inode) | |
259 | { | |
260 | struct binder_device *device = inode->i_private; | |
095cf502 | 261 | struct binderfs_info *info = BINDERFS_SB(inode->i_sb); |
3ad20fe3 CB |
262 | |
263 | clear_inode(inode); | |
264 | ||
0e13e452 | 265 | if (!S_ISCHR(inode->i_mode) || !device) |
3ad20fe3 CB |
266 | return; |
267 | ||
268 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 269 | --info->device_count; |
3ad20fe3 CB |
270 | ida_free(&binderfs_minors, device->miscdev.minor); |
271 | mutex_unlock(&binderfs_minors_mutex); | |
272 | ||
f0fe2c0f CB |
273 | if (refcount_dec_and_test(&device->ref)) { |
274 | kfree(device->context.name); | |
275 | kfree(device); | |
276 | } | |
3ad20fe3 CB |
277 | } |
278 | ||
095cf502 CB |
279 | static int binderfs_fs_context_parse_param(struct fs_context *fc, |
280 | struct fs_parameter *param) | |
849d540d | 281 | { |
095cf502 CB |
282 | int opt; |
283 | struct binderfs_mount_opts *ctx = fc->fs_private; | |
284 | struct fs_parse_result result; | |
f0083451 | 285 | |
095cf502 CB |
286 | opt = fs_parse(fc, binderfs_fs_parameters, param, &result); |
287 | if (opt < 0) | |
288 | return opt; | |
f0083451 | 289 | |
095cf502 CB |
290 | switch (opt) { |
291 | case Opt_max: | |
292 | if (result.uint_32 > BINDERFS_MAX_MINOR) | |
293 | return invalfc(fc, "Bad value for '%s'", param->key); | |
f0083451 | 294 | |
095cf502 CB |
295 | ctx->max = result.uint_32; |
296 | break; | |
297 | case Opt_stats_mode: | |
298 | if (!capable(CAP_SYS_ADMIN)) | |
299 | return -EPERM; | |
300 | ||
301 | ctx->stats_mode = result.uint_32; | |
302 | break; | |
303 | default: | |
304 | return invalfc(fc, "Unsupported parameter '%s'", param->key); | |
849d540d CB |
305 | } |
306 | ||
307 | return 0; | |
308 | } | |
309 | ||
095cf502 | 310 | static int binderfs_fs_context_reconfigure(struct fs_context *fc) |
849d540d | 311 | { |
095cf502 CB |
312 | struct binderfs_mount_opts *ctx = fc->fs_private; |
313 | struct binderfs_info *info = BINDERFS_SB(fc->root->d_sb); | |
f0083451 | 314 | |
095cf502 CB |
315 | if (info->mount_opts.stats_mode != ctx->stats_mode) |
316 | return invalfc(fc, "Binderfs stats mode cannot be changed during a remount"); | |
f0083451 | 317 | |
095cf502 CB |
318 | info->mount_opts.stats_mode = ctx->stats_mode; |
319 | info->mount_opts.max = ctx->max; | |
f0083451 | 320 | return 0; |
849d540d CB |
321 | } |
322 | ||
095cf502 | 323 | static int binderfs_show_options(struct seq_file *seq, struct dentry *root) |
849d540d | 324 | { |
095cf502 | 325 | struct binderfs_info *info = BINDERFS_SB(root->d_sb); |
849d540d | 326 | |
849d540d CB |
327 | if (info->mount_opts.max <= BINDERFS_MAX_MINOR) |
328 | seq_printf(seq, ",max=%d", info->mount_opts.max); | |
095cf502 CB |
329 | |
330 | switch (info->mount_opts.stats_mode) { | |
331 | case binderfs_stats_mode_unset: | |
332 | break; | |
333 | case binderfs_stats_mode_global: | |
f0083451 | 334 | seq_printf(seq, ",stats=global"); |
095cf502 CB |
335 | break; |
336 | } | |
849d540d CB |
337 | |
338 | return 0; | |
339 | } | |
340 | ||
095cf502 CB |
341 | static void binderfs_put_super(struct super_block *sb) |
342 | { | |
343 | struct binderfs_info *info = sb->s_fs_info; | |
344 | ||
345 | if (info && info->ipc_ns) | |
346 | put_ipc_ns(info->ipc_ns); | |
347 | ||
348 | kfree(info); | |
349 | sb->s_fs_info = NULL; | |
350 | } | |
351 | ||
3ad20fe3 | 352 | static const struct super_operations binderfs_super_ops = { |
849d540d | 353 | .evict_inode = binderfs_evict_inode, |
095cf502 | 354 | .show_options = binderfs_show_options, |
849d540d | 355 | .statfs = simple_statfs, |
095cf502 | 356 | .put_super = binderfs_put_super, |
3ad20fe3 CB |
357 | }; |
358 | ||
e98e6fa1 CB |
359 | static inline bool is_binderfs_control_device(const struct dentry *dentry) |
360 | { | |
361 | struct binderfs_info *info = dentry->d_sb->s_fs_info; | |
81195f96 | 362 | |
e98e6fa1 CB |
363 | return info->control_dentry == dentry; |
364 | } | |
365 | ||
549c7297 CB |
366 | static int binderfs_rename(struct user_namespace *mnt_userns, |
367 | struct inode *old_dir, struct dentry *old_dentry, | |
3ad20fe3 CB |
368 | struct inode *new_dir, struct dentry *new_dentry, |
369 | unsigned int flags) | |
370 | { | |
e98e6fa1 CB |
371 | if (is_binderfs_control_device(old_dentry) || |
372 | is_binderfs_control_device(new_dentry)) | |
3ad20fe3 CB |
373 | return -EPERM; |
374 | ||
549c7297 CB |
375 | return simple_rename(&init_user_ns, old_dir, old_dentry, new_dir, |
376 | new_dentry, flags); | |
3ad20fe3 CB |
377 | } |
378 | ||
379 | static int binderfs_unlink(struct inode *dir, struct dentry *dentry) | |
380 | { | |
e98e6fa1 | 381 | if (is_binderfs_control_device(dentry)) |
3ad20fe3 CB |
382 | return -EPERM; |
383 | ||
384 | return simple_unlink(dir, dentry); | |
385 | } | |
386 | ||
387 | static const struct file_operations binder_ctl_fops = { | |
388 | .owner = THIS_MODULE, | |
389 | .open = nonseekable_open, | |
390 | .unlocked_ioctl = binder_ctl_ioctl, | |
391 | .compat_ioctl = binder_ctl_ioctl, | |
392 | .llseek = noop_llseek, | |
393 | }; | |
394 | ||
395 | /** | |
396 | * binderfs_binder_ctl_create - create a new binder-control device | |
397 | * @sb: super block of the binderfs mount | |
398 | * | |
399 | * This function creates a new binder-control device node in the binderfs mount | |
400 | * referred to by @sb. | |
401 | * | |
402 | * Return: 0 on success, negative errno on failure | |
403 | */ | |
404 | static int binderfs_binder_ctl_create(struct super_block *sb) | |
405 | { | |
406 | int minor, ret; | |
407 | struct dentry *dentry; | |
408 | struct binder_device *device; | |
409 | struct inode *inode = NULL; | |
410 | struct dentry *root = sb->s_root; | |
411 | struct binderfs_info *info = sb->s_fs_info; | |
da8ddba5 CB |
412 | #if defined(CONFIG_IPC_NS) |
413 | bool use_reserve = (info->ipc_ns == &init_ipc_ns); | |
414 | #else | |
415 | bool use_reserve = true; | |
416 | #endif | |
3ad20fe3 CB |
417 | |
418 | device = kzalloc(sizeof(*device), GFP_KERNEL); | |
419 | if (!device) | |
420 | return -ENOMEM; | |
421 | ||
3ad20fe3 CB |
422 | /* If we have already created a binder-control node, return. */ |
423 | if (info->control_dentry) { | |
424 | ret = 0; | |
425 | goto out; | |
426 | } | |
427 | ||
428 | ret = -ENOMEM; | |
429 | inode = new_inode(sb); | |
430 | if (!inode) | |
431 | goto out; | |
432 | ||
433 | /* Reserve a new minor number for the new device. */ | |
434 | mutex_lock(&binderfs_minors_mutex); | |
da8ddba5 CB |
435 | minor = ida_alloc_max(&binderfs_minors, |
436 | use_reserve ? BINDERFS_MAX_MINOR : | |
437 | BINDERFS_MAX_MINOR_CAPPED, | |
438 | GFP_KERNEL); | |
3ad20fe3 CB |
439 | mutex_unlock(&binderfs_minors_mutex); |
440 | if (minor < 0) { | |
441 | ret = minor; | |
442 | goto out; | |
443 | } | |
444 | ||
445 | inode->i_ino = SECOND_INODE; | |
446 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
447 | init_special_inode(inode, S_IFCHR | 0600, | |
448 | MKDEV(MAJOR(binderfs_dev), minor)); | |
449 | inode->i_fop = &binder_ctl_fops; | |
450 | inode->i_uid = info->root_uid; | |
451 | inode->i_gid = info->root_gid; | |
452 | ||
211b64e4 | 453 | refcount_set(&device->ref, 1); |
3ad20fe3 CB |
454 | device->binderfs_inode = inode; |
455 | device->miscdev.minor = minor; | |
456 | ||
457 | dentry = d_alloc_name(root, "binder-control"); | |
458 | if (!dentry) | |
459 | goto out; | |
460 | ||
461 | inode->i_private = device; | |
462 | info->control_dentry = dentry; | |
463 | d_add(dentry, inode); | |
3ad20fe3 CB |
464 | |
465 | return 0; | |
466 | ||
467 | out: | |
3ad20fe3 CB |
468 | kfree(device); |
469 | iput(inode); | |
470 | ||
471 | return ret; | |
472 | } | |
473 | ||
474 | static const struct inode_operations binderfs_dir_inode_operations = { | |
475 | .lookup = simple_lookup, | |
476 | .rename = binderfs_rename, | |
477 | .unlink = binderfs_unlink, | |
478 | }; | |
479 | ||
0e13e452 HV |
480 | static struct inode *binderfs_make_inode(struct super_block *sb, int mode) |
481 | { | |
482 | struct inode *ret; | |
483 | ||
484 | ret = new_inode(sb); | |
485 | if (ret) { | |
486 | ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET); | |
487 | ret->i_mode = mode; | |
488 | ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); | |
489 | } | |
490 | return ret; | |
491 | } | |
492 | ||
493 | static struct dentry *binderfs_create_dentry(struct dentry *parent, | |
494 | const char *name) | |
495 | { | |
496 | struct dentry *dentry; | |
497 | ||
498 | dentry = lookup_one_len(name, parent, strlen(name)); | |
499 | if (IS_ERR(dentry)) | |
500 | return dentry; | |
501 | ||
502 | /* Return error if the file/dir already exists. */ | |
503 | if (d_really_is_positive(dentry)) { | |
504 | dput(dentry); | |
505 | return ERR_PTR(-EEXIST); | |
506 | } | |
507 | ||
508 | return dentry; | |
509 | } | |
510 | ||
4feb80fa HV |
511 | void binderfs_remove_file(struct dentry *dentry) |
512 | { | |
513 | struct inode *parent_inode; | |
514 | ||
515 | parent_inode = d_inode(dentry->d_parent); | |
516 | inode_lock(parent_inode); | |
517 | if (simple_positive(dentry)) { | |
518 | dget(dentry); | |
519 | simple_unlink(parent_inode, dentry); | |
520 | d_delete(dentry); | |
521 | dput(dentry); | |
522 | } | |
523 | inode_unlock(parent_inode); | |
524 | } | |
525 | ||
526 | struct dentry *binderfs_create_file(struct dentry *parent, const char *name, | |
527 | const struct file_operations *fops, | |
528 | void *data) | |
0e13e452 HV |
529 | { |
530 | struct dentry *dentry; | |
531 | struct inode *new_inode, *parent_inode; | |
532 | struct super_block *sb; | |
533 | ||
534 | parent_inode = d_inode(parent); | |
535 | inode_lock(parent_inode); | |
536 | ||
537 | dentry = binderfs_create_dentry(parent, name); | |
538 | if (IS_ERR(dentry)) | |
539 | goto out; | |
540 | ||
541 | sb = parent_inode->i_sb; | |
542 | new_inode = binderfs_make_inode(sb, S_IFREG | 0444); | |
543 | if (!new_inode) { | |
544 | dput(dentry); | |
545 | dentry = ERR_PTR(-ENOMEM); | |
546 | goto out; | |
547 | } | |
548 | ||
549 | new_inode->i_fop = fops; | |
550 | new_inode->i_private = data; | |
551 | d_instantiate(dentry, new_inode); | |
552 | fsnotify_create(parent_inode, dentry); | |
553 | ||
554 | out: | |
555 | inode_unlock(parent_inode); | |
556 | return dentry; | |
557 | } | |
558 | ||
559 | static struct dentry *binderfs_create_dir(struct dentry *parent, | |
560 | const char *name) | |
561 | { | |
562 | struct dentry *dentry; | |
563 | struct inode *new_inode, *parent_inode; | |
564 | struct super_block *sb; | |
565 | ||
566 | parent_inode = d_inode(parent); | |
567 | inode_lock(parent_inode); | |
568 | ||
569 | dentry = binderfs_create_dentry(parent, name); | |
570 | if (IS_ERR(dentry)) | |
571 | goto out; | |
572 | ||
573 | sb = parent_inode->i_sb; | |
574 | new_inode = binderfs_make_inode(sb, S_IFDIR | 0755); | |
575 | if (!new_inode) { | |
576 | dput(dentry); | |
577 | dentry = ERR_PTR(-ENOMEM); | |
578 | goto out; | |
579 | } | |
580 | ||
581 | new_inode->i_fop = &simple_dir_operations; | |
582 | new_inode->i_op = &simple_dir_inode_operations; | |
583 | ||
584 | set_nlink(new_inode, 2); | |
585 | d_instantiate(dentry, new_inode); | |
586 | inc_nlink(parent_inode); | |
587 | fsnotify_mkdir(parent_inode, dentry); | |
588 | ||
589 | out: | |
590 | inode_unlock(parent_inode); | |
591 | return dentry; | |
592 | } | |
593 | ||
fc470abf CL |
594 | static int binder_features_show(struct seq_file *m, void *unused) |
595 | { | |
596 | bool *feature = m->private; | |
597 | ||
598 | seq_printf(m, "%d\n", *feature); | |
599 | ||
600 | return 0; | |
601 | } | |
602 | DEFINE_SHOW_ATTRIBUTE(binder_features); | |
603 | ||
604 | static int init_binder_features(struct super_block *sb) | |
605 | { | |
606 | struct dentry *dentry, *dir; | |
607 | ||
608 | dir = binderfs_create_dir(sb->s_root, "features"); | |
609 | if (IS_ERR(dir)) | |
610 | return PTR_ERR(dir); | |
611 | ||
612 | dentry = binderfs_create_file(dir, "oneway_spam_detection", | |
613 | &binder_features_fops, | |
614 | &binder_features.oneway_spam_detection); | |
615 | if (IS_ERR(dentry)) | |
616 | return PTR_ERR(dentry); | |
617 | ||
618 | return 0; | |
619 | } | |
620 | ||
0e13e452 HV |
621 | static int init_binder_logs(struct super_block *sb) |
622 | { | |
4feb80fa HV |
623 | struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; |
624 | struct binderfs_info *info; | |
0e13e452 HV |
625 | int ret = 0; |
626 | ||
627 | binder_logs_root_dir = binderfs_create_dir(sb->s_root, | |
628 | "binder_logs"); | |
629 | if (IS_ERR(binder_logs_root_dir)) { | |
630 | ret = PTR_ERR(binder_logs_root_dir); | |
631 | goto out; | |
632 | } | |
633 | ||
634 | dentry = binderfs_create_file(binder_logs_root_dir, "stats", | |
635 | &binder_stats_fops, NULL); | |
636 | if (IS_ERR(dentry)) { | |
637 | ret = PTR_ERR(dentry); | |
638 | goto out; | |
639 | } | |
640 | ||
641 | dentry = binderfs_create_file(binder_logs_root_dir, "state", | |
642 | &binder_state_fops, NULL); | |
643 | if (IS_ERR(dentry)) { | |
644 | ret = PTR_ERR(dentry); | |
645 | goto out; | |
646 | } | |
647 | ||
648 | dentry = binderfs_create_file(binder_logs_root_dir, "transactions", | |
649 | &binder_transactions_fops, NULL); | |
03e2e07e HV |
650 | if (IS_ERR(dentry)) { |
651 | ret = PTR_ERR(dentry); | |
652 | goto out; | |
653 | } | |
654 | ||
655 | dentry = binderfs_create_file(binder_logs_root_dir, | |
656 | "transaction_log", | |
657 | &binder_transaction_log_fops, | |
658 | &binder_transaction_log); | |
659 | if (IS_ERR(dentry)) { | |
660 | ret = PTR_ERR(dentry); | |
661 | goto out; | |
662 | } | |
663 | ||
664 | dentry = binderfs_create_file(binder_logs_root_dir, | |
665 | "failed_transaction_log", | |
666 | &binder_transaction_log_fops, | |
667 | &binder_transaction_log_failed); | |
4feb80fa | 668 | if (IS_ERR(dentry)) { |
0e13e452 | 669 | ret = PTR_ERR(dentry); |
4feb80fa HV |
670 | goto out; |
671 | } | |
672 | ||
673 | proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); | |
674 | if (IS_ERR(proc_log_dir)) { | |
675 | ret = PTR_ERR(proc_log_dir); | |
676 | goto out; | |
677 | } | |
678 | info = sb->s_fs_info; | |
679 | info->proc_log_dir = proc_log_dir; | |
0e13e452 HV |
680 | |
681 | out: | |
682 | return ret; | |
683 | } | |
684 | ||
095cf502 | 685 | static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) |
3ad20fe3 | 686 | { |
36975fc3 | 687 | int ret; |
3ad20fe3 | 688 | struct binderfs_info *info; |
095cf502 | 689 | struct binderfs_mount_opts *ctx = fc->fs_private; |
3ad20fe3 | 690 | struct inode *inode = NULL; |
7a1c4f28 | 691 | struct binderfs_device device_info = {}; |
ca2864c6 HV |
692 | const char *name; |
693 | size_t len; | |
3ad20fe3 CB |
694 | |
695 | sb->s_blocksize = PAGE_SIZE; | |
696 | sb->s_blocksize_bits = PAGE_SHIFT; | |
697 | ||
698 | /* | |
699 | * The binderfs filesystem can be mounted by userns root in a | |
700 | * non-initial userns. By default such mounts have the SB_I_NODEV flag | |
701 | * set in s_iflags to prevent security issues where userns root can | |
702 | * just create random device nodes via mknod() since it owns the | |
703 | * filesystem mount. But binderfs does not allow to create any files | |
704 | * including devices nodes. The only way to create binder devices nodes | |
705 | * is through the binder-control device which userns root is explicitly | |
706 | * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both | |
707 | * necessary and safe. | |
708 | */ | |
709 | sb->s_iflags &= ~SB_I_NODEV; | |
710 | sb->s_iflags |= SB_I_NOEXEC; | |
711 | sb->s_magic = BINDERFS_SUPER_MAGIC; | |
712 | sb->s_op = &binderfs_super_ops; | |
713 | sb->s_time_gran = 1; | |
714 | ||
36975fc3 CB |
715 | sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); |
716 | if (!sb->s_fs_info) | |
717 | return -ENOMEM; | |
718 | info = sb->s_fs_info; | |
719 | ||
720 | info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
3ad20fe3 | 721 | |
3ad20fe3 CB |
722 | info->root_gid = make_kgid(sb->s_user_ns, 0); |
723 | if (!gid_valid(info->root_gid)) | |
724 | info->root_gid = GLOBAL_ROOT_GID; | |
725 | info->root_uid = make_kuid(sb->s_user_ns, 0); | |
726 | if (!uid_valid(info->root_uid)) | |
727 | info->root_uid = GLOBAL_ROOT_UID; | |
095cf502 CB |
728 | info->mount_opts.max = ctx->max; |
729 | info->mount_opts.stats_mode = ctx->stats_mode; | |
3ad20fe3 | 730 | |
3ad20fe3 CB |
731 | inode = new_inode(sb); |
732 | if (!inode) | |
36975fc3 | 733 | return -ENOMEM; |
3ad20fe3 CB |
734 | |
735 | inode->i_ino = FIRST_INODE; | |
736 | inode->i_fop = &simple_dir_operations; | |
737 | inode->i_mode = S_IFDIR | 0755; | |
738 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
739 | inode->i_op = &binderfs_dir_inode_operations; | |
740 | set_nlink(inode, 2); | |
741 | ||
742 | sb->s_root = d_make_root(inode); | |
743 | if (!sb->s_root) | |
36975fc3 | 744 | return -ENOMEM; |
3ad20fe3 | 745 | |
ca2864c6 HV |
746 | ret = binderfs_binder_ctl_create(sb); |
747 | if (ret) | |
748 | return ret; | |
749 | ||
750 | name = binder_devices_param; | |
751 | for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { | |
752 | strscpy(device_info.name, name, len + 1); | |
753 | ret = binderfs_binder_device_create(inode, NULL, &device_info); | |
754 | if (ret) | |
755 | return ret; | |
756 | name += len; | |
757 | if (*name == ',') | |
758 | name++; | |
759 | } | |
760 | ||
fc470abf CL |
761 | ret = init_binder_features(sb); |
762 | if (ret) | |
763 | return ret; | |
764 | ||
095cf502 | 765 | if (info->mount_opts.stats_mode == binderfs_stats_mode_global) |
0e13e452 HV |
766 | return init_binder_logs(sb); |
767 | ||
ca2864c6 | 768 | return 0; |
3ad20fe3 CB |
769 | } |
770 | ||
095cf502 | 771 | static int binderfs_fs_context_get_tree(struct fs_context *fc) |
3ad20fe3 | 772 | { |
095cf502 | 773 | return get_tree_nodev(fc, binderfs_fill_super); |
3ad20fe3 CB |
774 | } |
775 | ||
095cf502 | 776 | static void binderfs_fs_context_free(struct fs_context *fc) |
3ad20fe3 | 777 | { |
095cf502 | 778 | struct binderfs_mount_opts *ctx = fc->fs_private; |
3ad20fe3 | 779 | |
095cf502 CB |
780 | kfree(ctx); |
781 | } | |
41984795 | 782 | |
095cf502 CB |
783 | static const struct fs_context_operations binderfs_fs_context_ops = { |
784 | .free = binderfs_fs_context_free, | |
785 | .get_tree = binderfs_fs_context_get_tree, | |
786 | .parse_param = binderfs_fs_context_parse_param, | |
787 | .reconfigure = binderfs_fs_context_reconfigure, | |
788 | }; | |
3ad20fe3 | 789 | |
095cf502 CB |
790 | static int binderfs_init_fs_context(struct fs_context *fc) |
791 | { | |
9e306ba3 | 792 | struct binderfs_mount_opts *ctx; |
095cf502 CB |
793 | |
794 | ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL); | |
795 | if (!ctx) | |
796 | return -ENOMEM; | |
797 | ||
798 | ctx->max = BINDERFS_MAX_MINOR; | |
799 | ctx->stats_mode = binderfs_stats_mode_unset; | |
800 | ||
801 | fc->fs_private = ctx; | |
802 | fc->ops = &binderfs_fs_context_ops; | |
803 | ||
804 | return 0; | |
3ad20fe3 CB |
805 | } |
806 | ||
807 | static struct file_system_type binder_fs_type = { | |
095cf502 CB |
808 | .name = "binder", |
809 | .init_fs_context = binderfs_init_fs_context, | |
810 | .parameters = binderfs_fs_parameters, | |
811 | .kill_sb = kill_litter_super, | |
812 | .fs_flags = FS_USERNS_MOUNT, | |
3ad20fe3 CB |
813 | }; |
814 | ||
5b9633af | 815 | int __init init_binderfs(void) |
3ad20fe3 CB |
816 | { |
817 | int ret; | |
028fb582 HV |
818 | const char *name; |
819 | size_t len; | |
820 | ||
821 | /* Verify that the default binderfs device names are valid. */ | |
822 | name = binder_devices_param; | |
823 | for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { | |
824 | if (len > BINDERFS_MAX_NAME) | |
825 | return -E2BIG; | |
826 | name += len; | |
827 | if (*name == ',') | |
828 | name++; | |
829 | } | |
3ad20fe3 CB |
830 | |
831 | /* Allocate new major number for binderfs. */ | |
832 | ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, | |
833 | "binder"); | |
834 | if (ret) | |
835 | return ret; | |
836 | ||
837 | ret = register_filesystem(&binder_fs_type); | |
838 | if (ret) { | |
839 | unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); | |
840 | return ret; | |
841 | } | |
842 | ||
3ad20fe3 CB |
843 | return ret; |
844 | } |