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 | |
3ad20fe3 | 42 | #define BINDERFS_MAX_MINOR (1U << MINORBITS) |
36bdf3ca CB |
43 | /* Ensure that the initial ipc namespace always has devices available. */ |
44 | #define BINDERFS_MAX_MINOR_CAPPED (BINDERFS_MAX_MINOR - 4) | |
3ad20fe3 | 45 | |
3ad20fe3 CB |
46 | static dev_t binderfs_dev; |
47 | static DEFINE_MUTEX(binderfs_minors_mutex); | |
48 | static DEFINE_IDA(binderfs_minors); | |
49 | ||
095cf502 | 50 | enum binderfs_param { |
849d540d | 51 | Opt_max, |
f0083451 | 52 | Opt_stats_mode, |
849d540d CB |
53 | }; |
54 | ||
f0083451 | 55 | enum binderfs_stats_mode { |
095cf502 CB |
56 | binderfs_stats_mode_unset, |
57 | binderfs_stats_mode_global, | |
f0083451 HV |
58 | }; |
59 | ||
fc470abf CL |
60 | struct binder_features { |
61 | bool oneway_spam_detection; | |
d23386ed | 62 | bool extended_error; |
fc470abf CL |
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, | |
d23386ed | 78 | .extended_error = true, |
fc470abf CL |
79 | }; |
80 | ||
095cf502 | 81 | static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb) |
3ad20fe3 | 82 | { |
095cf502 | 83 | return sb->s_fs_info; |
3ad20fe3 CB |
84 | } |
85 | ||
86 | bool is_binderfs_device(const struct inode *inode) | |
87 | { | |
88 | if (inode->i_sb->s_magic == BINDERFS_SUPER_MAGIC) | |
89 | return true; | |
90 | ||
91 | return false; | |
92 | } | |
93 | ||
94 | /** | |
95 | * binderfs_binder_device_create - allocate inode from super block of a | |
96 | * binderfs mount | |
97 | * @ref_inode: inode from wich the super block will be taken | |
98 | * @userp: buffer to copy information about new device for userspace to | |
99 | * @req: struct binderfs_device as copied from userspace | |
100 | * | |
01b3f1fc | 101 | * This function allocates a new binder_device and reserves a new minor |
3ad20fe3 CB |
102 | * number for it. |
103 | * Minor numbers are limited and tracked globally in binderfs_minors. The | |
104 | * function will stash a struct binder_device for the specific binder | |
105 | * device in i_private of the inode. | |
106 | * It will go on to allocate a new inode from the super block of the | |
107 | * filesystem mount, stash a struct binder_device in its i_private field | |
108 | * and attach a dentry to that inode. | |
109 | * | |
110 | * Return: 0 on success, negative errno on failure | |
111 | */ | |
112 | static int binderfs_binder_device_create(struct inode *ref_inode, | |
113 | struct binderfs_device __user *userp, | |
114 | struct binderfs_device *req) | |
115 | { | |
116 | int minor, ret; | |
01b3f1fc | 117 | struct dentry *dentry, *root; |
3ad20fe3 | 118 | struct binder_device *device; |
3ad20fe3 | 119 | char *name = NULL; |
01b3f1fc | 120 | size_t name_len; |
3ad20fe3 CB |
121 | struct inode *inode = NULL; |
122 | struct super_block *sb = ref_inode->i_sb; | |
123 | struct binderfs_info *info = sb->s_fs_info; | |
7fefaadd | 124 | #if defined(CONFIG_IPC_NS) |
36bdf3ca | 125 | bool use_reserve = (info->ipc_ns == &init_ipc_ns); |
7fefaadd CB |
126 | #else |
127 | bool use_reserve = true; | |
128 | #endif | |
3ad20fe3 CB |
129 | |
130 | /* Reserve new minor number for the new device. */ | |
131 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 132 | if (++info->device_count <= info->mount_opts.max) |
36bdf3ca CB |
133 | minor = ida_alloc_max(&binderfs_minors, |
134 | use_reserve ? BINDERFS_MAX_MINOR : | |
135 | BINDERFS_MAX_MINOR_CAPPED, | |
849d540d CB |
136 | GFP_KERNEL); |
137 | else | |
138 | minor = -ENOSPC; | |
139 | if (minor < 0) { | |
140 | --info->device_count; | |
141 | mutex_unlock(&binderfs_minors_mutex); | |
3ad20fe3 | 142 | return minor; |
849d540d CB |
143 | } |
144 | mutex_unlock(&binderfs_minors_mutex); | |
3ad20fe3 CB |
145 | |
146 | ret = -ENOMEM; | |
147 | device = kzalloc(sizeof(*device), GFP_KERNEL); | |
148 | if (!device) | |
149 | goto err; | |
150 | ||
151 | inode = new_inode(sb); | |
152 | if (!inode) | |
153 | goto err; | |
154 | ||
155 | inode->i_ino = minor + INODE_OFFSET; | |
156 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
157 | init_special_inode(inode, S_IFCHR | 0600, | |
158 | MKDEV(MAJOR(binderfs_dev), minor)); | |
159 | inode->i_fop = &binder_fops; | |
160 | inode->i_uid = info->root_uid; | |
161 | inode->i_gid = info->root_gid; | |
162 | ||
01b3f1fc CB |
163 | req->name[BINDERFS_MAX_NAME] = '\0'; /* NUL-terminate */ |
164 | name_len = strlen(req->name); | |
165 | /* Make sure to include terminating NUL byte */ | |
166 | name = kmemdup(req->name, name_len + 1, GFP_KERNEL); | |
3ad20fe3 CB |
167 | if (!name) |
168 | goto err; | |
169 | ||
f0fe2c0f | 170 | refcount_set(&device->ref, 1); |
3ad20fe3 CB |
171 | device->binderfs_inode = inode; |
172 | device->context.binder_context_mgr_uid = INVALID_UID; | |
173 | device->context.name = name; | |
174 | device->miscdev.name = name; | |
175 | device->miscdev.minor = minor; | |
176 | mutex_init(&device->context.context_mgr_node_lock); | |
177 | ||
178 | req->major = MAJOR(binderfs_dev); | |
179 | req->minor = minor; | |
180 | ||
ca2864c6 | 181 | if (userp && copy_to_user(userp, req, sizeof(*req))) { |
3ad20fe3 CB |
182 | ret = -EFAULT; |
183 | goto err; | |
184 | } | |
185 | ||
186 | root = sb->s_root; | |
187 | inode_lock(d_inode(root)); | |
01b3f1fc CB |
188 | |
189 | /* look it up */ | |
190 | dentry = lookup_one_len(name, root, name_len); | |
191 | if (IS_ERR(dentry)) { | |
3ad20fe3 | 192 | inode_unlock(d_inode(root)); |
01b3f1fc | 193 | ret = PTR_ERR(dentry); |
3ad20fe3 CB |
194 | goto err; |
195 | } | |
196 | ||
01b3f1fc CB |
197 | if (d_really_is_positive(dentry)) { |
198 | /* already exists */ | |
199 | dput(dentry); | |
200 | inode_unlock(d_inode(root)); | |
201 | ret = -EEXIST; | |
202 | goto err; | |
3ad20fe3 CB |
203 | } |
204 | ||
205 | inode->i_private = device; | |
01684db9 | 206 | d_instantiate(dentry, inode); |
3ad20fe3 CB |
207 | fsnotify_create(root->d_inode, dentry); |
208 | inode_unlock(d_inode(root)); | |
209 | ||
210 | return 0; | |
211 | ||
212 | err: | |
213 | kfree(name); | |
214 | kfree(device); | |
215 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 216 | --info->device_count; |
3ad20fe3 CB |
217 | ida_free(&binderfs_minors, minor); |
218 | mutex_unlock(&binderfs_minors_mutex); | |
219 | iput(inode); | |
220 | ||
221 | return ret; | |
222 | } | |
223 | ||
224 | /** | |
ad228a34 | 225 | * binder_ctl_ioctl - handle binder device node allocation requests |
3ad20fe3 CB |
226 | * |
227 | * The request handler for the binder-control device. All requests operate on | |
228 | * the binderfs mount the binder-control device resides in: | |
229 | * - BINDER_CTL_ADD | |
230 | * Allocate a new binder device. | |
231 | * | |
ad228a34 | 232 | * Return: %0 on success, negative errno on failure. |
3ad20fe3 CB |
233 | */ |
234 | static long binder_ctl_ioctl(struct file *file, unsigned int cmd, | |
235 | unsigned long arg) | |
236 | { | |
237 | int ret = -EINVAL; | |
238 | struct inode *inode = file_inode(file); | |
239 | struct binderfs_device __user *device = (struct binderfs_device __user *)arg; | |
240 | struct binderfs_device device_req; | |
241 | ||
242 | switch (cmd) { | |
243 | case BINDER_CTL_ADD: | |
244 | ret = copy_from_user(&device_req, device, sizeof(device_req)); | |
245 | if (ret) { | |
246 | ret = -EFAULT; | |
247 | break; | |
248 | } | |
249 | ||
250 | ret = binderfs_binder_device_create(inode, device, &device_req); | |
251 | break; | |
252 | default: | |
253 | break; | |
254 | } | |
255 | ||
256 | return ret; | |
257 | } | |
258 | ||
259 | static void binderfs_evict_inode(struct inode *inode) | |
260 | { | |
261 | struct binder_device *device = inode->i_private; | |
095cf502 | 262 | struct binderfs_info *info = BINDERFS_SB(inode->i_sb); |
3ad20fe3 CB |
263 | |
264 | clear_inode(inode); | |
265 | ||
0e13e452 | 266 | if (!S_ISCHR(inode->i_mode) || !device) |
3ad20fe3 CB |
267 | return; |
268 | ||
269 | mutex_lock(&binderfs_minors_mutex); | |
849d540d | 270 | --info->device_count; |
3ad20fe3 CB |
271 | ida_free(&binderfs_minors, device->miscdev.minor); |
272 | mutex_unlock(&binderfs_minors_mutex); | |
273 | ||
f0fe2c0f CB |
274 | if (refcount_dec_and_test(&device->ref)) { |
275 | kfree(device->context.name); | |
276 | kfree(device); | |
277 | } | |
3ad20fe3 CB |
278 | } |
279 | ||
095cf502 CB |
280 | static int binderfs_fs_context_parse_param(struct fs_context *fc, |
281 | struct fs_parameter *param) | |
849d540d | 282 | { |
095cf502 CB |
283 | int opt; |
284 | struct binderfs_mount_opts *ctx = fc->fs_private; | |
285 | struct fs_parse_result result; | |
f0083451 | 286 | |
095cf502 CB |
287 | opt = fs_parse(fc, binderfs_fs_parameters, param, &result); |
288 | if (opt < 0) | |
289 | return opt; | |
f0083451 | 290 | |
095cf502 CB |
291 | switch (opt) { |
292 | case Opt_max: | |
293 | if (result.uint_32 > BINDERFS_MAX_MINOR) | |
294 | return invalfc(fc, "Bad value for '%s'", param->key); | |
f0083451 | 295 | |
095cf502 CB |
296 | ctx->max = result.uint_32; |
297 | break; | |
298 | case Opt_stats_mode: | |
299 | if (!capable(CAP_SYS_ADMIN)) | |
300 | return -EPERM; | |
301 | ||
302 | ctx->stats_mode = result.uint_32; | |
303 | break; | |
304 | default: | |
305 | return invalfc(fc, "Unsupported parameter '%s'", param->key); | |
849d540d CB |
306 | } |
307 | ||
308 | return 0; | |
309 | } | |
310 | ||
095cf502 | 311 | static int binderfs_fs_context_reconfigure(struct fs_context *fc) |
849d540d | 312 | { |
095cf502 CB |
313 | struct binderfs_mount_opts *ctx = fc->fs_private; |
314 | struct binderfs_info *info = BINDERFS_SB(fc->root->d_sb); | |
f0083451 | 315 | |
095cf502 CB |
316 | if (info->mount_opts.stats_mode != ctx->stats_mode) |
317 | return invalfc(fc, "Binderfs stats mode cannot be changed during a remount"); | |
f0083451 | 318 | |
095cf502 CB |
319 | info->mount_opts.stats_mode = ctx->stats_mode; |
320 | info->mount_opts.max = ctx->max; | |
f0083451 | 321 | return 0; |
849d540d CB |
322 | } |
323 | ||
095cf502 | 324 | static int binderfs_show_options(struct seq_file *seq, struct dentry *root) |
849d540d | 325 | { |
095cf502 | 326 | struct binderfs_info *info = BINDERFS_SB(root->d_sb); |
849d540d | 327 | |
849d540d CB |
328 | if (info->mount_opts.max <= BINDERFS_MAX_MINOR) |
329 | seq_printf(seq, ",max=%d", info->mount_opts.max); | |
095cf502 CB |
330 | |
331 | switch (info->mount_opts.stats_mode) { | |
332 | case binderfs_stats_mode_unset: | |
333 | break; | |
334 | case binderfs_stats_mode_global: | |
f0083451 | 335 | seq_printf(seq, ",stats=global"); |
095cf502 CB |
336 | break; |
337 | } | |
849d540d CB |
338 | |
339 | return 0; | |
340 | } | |
341 | ||
3ad20fe3 | 342 | static const struct super_operations binderfs_super_ops = { |
849d540d | 343 | .evict_inode = binderfs_evict_inode, |
095cf502 | 344 | .show_options = binderfs_show_options, |
849d540d | 345 | .statfs = simple_statfs, |
3ad20fe3 CB |
346 | }; |
347 | ||
e98e6fa1 CB |
348 | static inline bool is_binderfs_control_device(const struct dentry *dentry) |
349 | { | |
350 | struct binderfs_info *info = dentry->d_sb->s_fs_info; | |
81195f96 | 351 | |
e98e6fa1 CB |
352 | return info->control_dentry == dentry; |
353 | } | |
354 | ||
e18275ae | 355 | static int binderfs_rename(struct mnt_idmap *idmap, |
549c7297 | 356 | struct inode *old_dir, struct dentry *old_dentry, |
3ad20fe3 CB |
357 | struct inode *new_dir, struct dentry *new_dentry, |
358 | unsigned int flags) | |
359 | { | |
e98e6fa1 CB |
360 | if (is_binderfs_control_device(old_dentry) || |
361 | is_binderfs_control_device(new_dentry)) | |
3ad20fe3 CB |
362 | return -EPERM; |
363 | ||
e18275ae | 364 | return simple_rename(idmap, old_dir, old_dentry, new_dir, |
549c7297 | 365 | 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 | ||
fc470abf CL |
583 | static int binder_features_show(struct seq_file *m, void *unused) |
584 | { | |
585 | bool *feature = m->private; | |
586 | ||
587 | seq_printf(m, "%d\n", *feature); | |
588 | ||
589 | return 0; | |
590 | } | |
591 | DEFINE_SHOW_ATTRIBUTE(binder_features); | |
592 | ||
593 | static int init_binder_features(struct super_block *sb) | |
594 | { | |
595 | struct dentry *dentry, *dir; | |
596 | ||
597 | dir = binderfs_create_dir(sb->s_root, "features"); | |
598 | if (IS_ERR(dir)) | |
599 | return PTR_ERR(dir); | |
600 | ||
601 | dentry = binderfs_create_file(dir, "oneway_spam_detection", | |
602 | &binder_features_fops, | |
603 | &binder_features.oneway_spam_detection); | |
604 | if (IS_ERR(dentry)) | |
605 | return PTR_ERR(dentry); | |
606 | ||
d23386ed CL |
607 | dentry = binderfs_create_file(dir, "extended_error", |
608 | &binder_features_fops, | |
609 | &binder_features.extended_error); | |
610 | if (IS_ERR(dentry)) | |
611 | return PTR_ERR(dentry); | |
612 | ||
fc470abf CL |
613 | return 0; |
614 | } | |
615 | ||
0e13e452 HV |
616 | static int init_binder_logs(struct super_block *sb) |
617 | { | |
4feb80fa | 618 | struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir; |
b7e241bb | 619 | const struct binder_debugfs_entry *db_entry; |
4feb80fa | 620 | struct binderfs_info *info; |
0e13e452 HV |
621 | int ret = 0; |
622 | ||
623 | binder_logs_root_dir = binderfs_create_dir(sb->s_root, | |
624 | "binder_logs"); | |
625 | if (IS_ERR(binder_logs_root_dir)) { | |
626 | ret = PTR_ERR(binder_logs_root_dir); | |
627 | goto out; | |
628 | } | |
629 | ||
b7e241bb CL |
630 | binder_for_each_debugfs_entry(db_entry) { |
631 | dentry = binderfs_create_file(binder_logs_root_dir, | |
632 | db_entry->name, | |
633 | db_entry->fops, | |
634 | db_entry->data); | |
635 | if (IS_ERR(dentry)) { | |
636 | ret = PTR_ERR(dentry); | |
637 | goto out; | |
638 | } | |
4feb80fa HV |
639 | } |
640 | ||
641 | proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc"); | |
642 | if (IS_ERR(proc_log_dir)) { | |
643 | ret = PTR_ERR(proc_log_dir); | |
644 | goto out; | |
645 | } | |
646 | info = sb->s_fs_info; | |
647 | info->proc_log_dir = proc_log_dir; | |
0e13e452 HV |
648 | |
649 | out: | |
650 | return ret; | |
651 | } | |
652 | ||
095cf502 | 653 | static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) |
3ad20fe3 | 654 | { |
36975fc3 | 655 | int ret; |
3ad20fe3 | 656 | struct binderfs_info *info; |
095cf502 | 657 | struct binderfs_mount_opts *ctx = fc->fs_private; |
3ad20fe3 | 658 | struct inode *inode = NULL; |
7a1c4f28 | 659 | struct binderfs_device device_info = {}; |
ca2864c6 HV |
660 | const char *name; |
661 | size_t len; | |
3ad20fe3 CB |
662 | |
663 | sb->s_blocksize = PAGE_SIZE; | |
664 | sb->s_blocksize_bits = PAGE_SHIFT; | |
665 | ||
666 | /* | |
667 | * The binderfs filesystem can be mounted by userns root in a | |
668 | * non-initial userns. By default such mounts have the SB_I_NODEV flag | |
669 | * set in s_iflags to prevent security issues where userns root can | |
670 | * just create random device nodes via mknod() since it owns the | |
671 | * filesystem mount. But binderfs does not allow to create any files | |
672 | * including devices nodes. The only way to create binder devices nodes | |
673 | * is through the binder-control device which userns root is explicitly | |
674 | * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both | |
675 | * necessary and safe. | |
676 | */ | |
677 | sb->s_iflags &= ~SB_I_NODEV; | |
678 | sb->s_iflags |= SB_I_NOEXEC; | |
679 | sb->s_magic = BINDERFS_SUPER_MAGIC; | |
680 | sb->s_op = &binderfs_super_ops; | |
681 | sb->s_time_gran = 1; | |
682 | ||
36975fc3 CB |
683 | sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL); |
684 | if (!sb->s_fs_info) | |
685 | return -ENOMEM; | |
686 | info = sb->s_fs_info; | |
687 | ||
688 | info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
3ad20fe3 | 689 | |
3ad20fe3 CB |
690 | info->root_gid = make_kgid(sb->s_user_ns, 0); |
691 | if (!gid_valid(info->root_gid)) | |
692 | info->root_gid = GLOBAL_ROOT_GID; | |
693 | info->root_uid = make_kuid(sb->s_user_ns, 0); | |
694 | if (!uid_valid(info->root_uid)) | |
695 | info->root_uid = GLOBAL_ROOT_UID; | |
095cf502 CB |
696 | info->mount_opts.max = ctx->max; |
697 | info->mount_opts.stats_mode = ctx->stats_mode; | |
3ad20fe3 | 698 | |
3ad20fe3 CB |
699 | inode = new_inode(sb); |
700 | if (!inode) | |
36975fc3 | 701 | return -ENOMEM; |
3ad20fe3 CB |
702 | |
703 | inode->i_ino = FIRST_INODE; | |
704 | inode->i_fop = &simple_dir_operations; | |
705 | inode->i_mode = S_IFDIR | 0755; | |
706 | inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); | |
707 | inode->i_op = &binderfs_dir_inode_operations; | |
708 | set_nlink(inode, 2); | |
709 | ||
710 | sb->s_root = d_make_root(inode); | |
711 | if (!sb->s_root) | |
36975fc3 | 712 | return -ENOMEM; |
3ad20fe3 | 713 | |
ca2864c6 HV |
714 | ret = binderfs_binder_ctl_create(sb); |
715 | if (ret) | |
716 | return ret; | |
717 | ||
718 | name = binder_devices_param; | |
719 | for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { | |
720 | strscpy(device_info.name, name, len + 1); | |
721 | ret = binderfs_binder_device_create(inode, NULL, &device_info); | |
722 | if (ret) | |
723 | return ret; | |
724 | name += len; | |
725 | if (*name == ',') | |
726 | name++; | |
727 | } | |
728 | ||
fc470abf CL |
729 | ret = init_binder_features(sb); |
730 | if (ret) | |
731 | return ret; | |
732 | ||
095cf502 | 733 | if (info->mount_opts.stats_mode == binderfs_stats_mode_global) |
0e13e452 HV |
734 | return init_binder_logs(sb); |
735 | ||
ca2864c6 | 736 | return 0; |
3ad20fe3 CB |
737 | } |
738 | ||
095cf502 | 739 | static int binderfs_fs_context_get_tree(struct fs_context *fc) |
3ad20fe3 | 740 | { |
095cf502 | 741 | return get_tree_nodev(fc, binderfs_fill_super); |
3ad20fe3 CB |
742 | } |
743 | ||
095cf502 | 744 | static void binderfs_fs_context_free(struct fs_context *fc) |
3ad20fe3 | 745 | { |
095cf502 | 746 | struct binderfs_mount_opts *ctx = fc->fs_private; |
3ad20fe3 | 747 | |
095cf502 CB |
748 | kfree(ctx); |
749 | } | |
41984795 | 750 | |
095cf502 CB |
751 | static const struct fs_context_operations binderfs_fs_context_ops = { |
752 | .free = binderfs_fs_context_free, | |
753 | .get_tree = binderfs_fs_context_get_tree, | |
754 | .parse_param = binderfs_fs_context_parse_param, | |
755 | .reconfigure = binderfs_fs_context_reconfigure, | |
756 | }; | |
3ad20fe3 | 757 | |
095cf502 CB |
758 | static int binderfs_init_fs_context(struct fs_context *fc) |
759 | { | |
9e306ba3 | 760 | struct binderfs_mount_opts *ctx; |
095cf502 CB |
761 | |
762 | ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL); | |
763 | if (!ctx) | |
764 | return -ENOMEM; | |
765 | ||
766 | ctx->max = BINDERFS_MAX_MINOR; | |
767 | ctx->stats_mode = binderfs_stats_mode_unset; | |
768 | ||
769 | fc->fs_private = ctx; | |
770 | fc->ops = &binderfs_fs_context_ops; | |
771 | ||
772 | return 0; | |
3ad20fe3 CB |
773 | } |
774 | ||
9d64d240 AV |
775 | static void binderfs_kill_super(struct super_block *sb) |
776 | { | |
777 | struct binderfs_info *info = sb->s_fs_info; | |
778 | ||
779 | /* | |
780 | * During inode eviction struct binderfs_info is needed. | |
781 | * So first wipe the super_block then free struct binderfs_info. | |
782 | */ | |
783 | kill_litter_super(sb); | |
784 | ||
785 | if (info && info->ipc_ns) | |
786 | put_ipc_ns(info->ipc_ns); | |
787 | ||
788 | kfree(info); | |
789 | } | |
790 | ||
3ad20fe3 | 791 | static struct file_system_type binder_fs_type = { |
095cf502 CB |
792 | .name = "binder", |
793 | .init_fs_context = binderfs_init_fs_context, | |
794 | .parameters = binderfs_fs_parameters, | |
9d64d240 | 795 | .kill_sb = binderfs_kill_super, |
095cf502 | 796 | .fs_flags = FS_USERNS_MOUNT, |
3ad20fe3 CB |
797 | }; |
798 | ||
5b9633af | 799 | int __init init_binderfs(void) |
3ad20fe3 CB |
800 | { |
801 | int ret; | |
028fb582 HV |
802 | const char *name; |
803 | size_t len; | |
804 | ||
805 | /* Verify that the default binderfs device names are valid. */ | |
806 | name = binder_devices_param; | |
807 | for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) { | |
808 | if (len > BINDERFS_MAX_NAME) | |
809 | return -E2BIG; | |
810 | name += len; | |
811 | if (*name == ',') | |
812 | name++; | |
813 | } | |
3ad20fe3 CB |
814 | |
815 | /* Allocate new major number for binderfs. */ | |
816 | ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR, | |
817 | "binder"); | |
818 | if (ret) | |
819 | return ret; | |
820 | ||
821 | ret = register_filesystem(&binder_fs_type); | |
822 | if (ret) { | |
823 | unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR); | |
824 | return ret; | |
825 | } | |
826 | ||
3ad20fe3 CB |
827 | return ret; |
828 | } |