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>
14 #include <linux/namei.h>
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>
21 #include <linux/fs_parser.h>
22 #include <linux/radix-tree.h>
23 #include <linux/sched.h>
24 #include <linux/seq_file.h>
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>
35 #include <uapi/linux/android/binderfs.h>
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)
44 /* Ensure that the initial ipc namespace always has devices available. */
45 #define BINDERFS_MAX_MINOR_CAPPED (BINDERFS_MAX_MINOR - 4)
46
47 static dev_t binderfs_dev;
48 static DEFINE_MUTEX(binderfs_minors_mutex);
49 static DEFINE_IDA(binderfs_minors);
50
51 enum binderfs_param {
52 Opt_max,
53 Opt_stats_mode,
54 };
55
56 enum binderfs_stats_mode {
57 binderfs_stats_mode_unset,
58 binderfs_stats_mode_global,
59 };
60
61 struct binder_features {
62 bool oneway_spam_detection;
63 };
64
65 static const struct constant_table binderfs_param_stats[] = {
66 { "global", binderfs_stats_mode_global },
67 {}
68 };
69
70 static const struct fs_parameter_spec binderfs_fs_parameters[] = {
71 fsparam_u32("max", Opt_max),
72 fsparam_enum("stats", Opt_stats_mode, binderfs_param_stats),
73 {}
74 };
75
76 static struct binder_features binder_features = {
77 .oneway_spam_detection = true,
78 };
79
BINDERFS_SB(const struct super_block * sb)80 static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb)
81 {
82 return sb->s_fs_info;
83 }
84
is_binderfs_device(const struct inode * inode)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 *
100 * This function allocates a new binder_device and reserves a new minor
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 */
binderfs_binder_device_create(struct inode * ref_inode,struct binderfs_device __user * userp,struct binderfs_device * req)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;
116 struct dentry *dentry, *root;
117 struct binder_device *device;
118 char *name = NULL;
119 size_t name_len;
120 struct inode *inode = NULL;
121 struct super_block *sb = ref_inode->i_sb;
122 struct binderfs_info *info = sb->s_fs_info;
123 #if defined(CONFIG_IPC_NS)
124 bool use_reserve = (info->ipc_ns == &init_ipc_ns);
125 #else
126 bool use_reserve = true;
127 #endif
128
129 /* Reserve new minor number for the new device. */
130 mutex_lock(&binderfs_minors_mutex);
131 if (++info->device_count <= info->mount_opts.max)
132 minor = ida_alloc_max(&binderfs_minors,
133 use_reserve ? BINDERFS_MAX_MINOR :
134 BINDERFS_MAX_MINOR_CAPPED,
135 GFP_KERNEL);
136 else
137 minor = -ENOSPC;
138 if (minor < 0) {
139 --info->device_count;
140 mutex_unlock(&binderfs_minors_mutex);
141 return minor;
142 }
143 mutex_unlock(&binderfs_minors_mutex);
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
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);
166 if (!name)
167 goto err;
168
169 refcount_set(&device->ref, 1);
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
180 if (userp && copy_to_user(userp, req, sizeof(*req))) {
181 ret = -EFAULT;
182 goto err;
183 }
184
185 root = sb->s_root;
186 inode_lock(d_inode(root));
187
188 /* look it up */
189 dentry = lookup_one_len(name, root, name_len);
190 if (IS_ERR(dentry)) {
191 inode_unlock(d_inode(root));
192 ret = PTR_ERR(dentry);
193 goto err;
194 }
195
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;
202 }
203
204 inode->i_private = device;
205 d_instantiate(dentry, inode);
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);
215 --info->device_count;
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 */
binder_ctl_ioctl(struct file * file,unsigned int cmd,unsigned long arg)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
binderfs_evict_inode(struct inode * inode)258 static void binderfs_evict_inode(struct inode *inode)
259 {
260 struct binder_device *device = inode->i_private;
261 struct binderfs_info *info = BINDERFS_SB(inode->i_sb);
262
263 clear_inode(inode);
264
265 if (!S_ISCHR(inode->i_mode) || !device)
266 return;
267
268 mutex_lock(&binderfs_minors_mutex);
269 --info->device_count;
270 ida_free(&binderfs_minors, device->miscdev.minor);
271 mutex_unlock(&binderfs_minors_mutex);
272
273 if (refcount_dec_and_test(&device->ref)) {
274 kfree(device->context.name);
275 kfree(device);
276 }
277 }
278
binderfs_fs_context_parse_param(struct fs_context * fc,struct fs_parameter * param)279 static int binderfs_fs_context_parse_param(struct fs_context *fc,
280 struct fs_parameter *param)
281 {
282 int opt;
283 struct binderfs_mount_opts *ctx = fc->fs_private;
284 struct fs_parse_result result;
285
286 opt = fs_parse(fc, binderfs_fs_parameters, param, &result);
287 if (opt < 0)
288 return opt;
289
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);
294
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);
305 }
306
307 return 0;
308 }
309
binderfs_fs_context_reconfigure(struct fs_context * fc)310 static int binderfs_fs_context_reconfigure(struct fs_context *fc)
311 {
312 struct binderfs_mount_opts *ctx = fc->fs_private;
313 struct binderfs_info *info = BINDERFS_SB(fc->root->d_sb);
314
315 if (info->mount_opts.stats_mode != ctx->stats_mode)
316 return invalfc(fc, "Binderfs stats mode cannot be changed during a remount");
317
318 info->mount_opts.stats_mode = ctx->stats_mode;
319 info->mount_opts.max = ctx->max;
320 return 0;
321 }
322
binderfs_show_options(struct seq_file * seq,struct dentry * root)323 static int binderfs_show_options(struct seq_file *seq, struct dentry *root)
324 {
325 struct binderfs_info *info = BINDERFS_SB(root->d_sb);
326
327 if (info->mount_opts.max <= BINDERFS_MAX_MINOR)
328 seq_printf(seq, ",max=%d", info->mount_opts.max);
329
330 switch (info->mount_opts.stats_mode) {
331 case binderfs_stats_mode_unset:
332 break;
333 case binderfs_stats_mode_global:
334 seq_printf(seq, ",stats=global");
335 break;
336 }
337
338 return 0;
339 }
340
binderfs_put_super(struct super_block * sb)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
352 static const struct super_operations binderfs_super_ops = {
353 .evict_inode = binderfs_evict_inode,
354 .show_options = binderfs_show_options,
355 .statfs = simple_statfs,
356 .put_super = binderfs_put_super,
357 };
358
is_binderfs_control_device(const struct dentry * dentry)359 static inline bool is_binderfs_control_device(const struct dentry *dentry)
360 {
361 struct binderfs_info *info = dentry->d_sb->s_fs_info;
362
363 return info->control_dentry == dentry;
364 }
365
binderfs_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)366 static int binderfs_rename(struct inode *old_dir, struct dentry *old_dentry,
367 struct inode *new_dir, struct dentry *new_dentry,
368 unsigned int flags)
369 {
370 if (is_binderfs_control_device(old_dentry) ||
371 is_binderfs_control_device(new_dentry))
372 return -EPERM;
373
374 return simple_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
375 }
376
binderfs_unlink(struct inode * dir,struct dentry * dentry)377 static int binderfs_unlink(struct inode *dir, struct dentry *dentry)
378 {
379 if (is_binderfs_control_device(dentry))
380 return -EPERM;
381
382 return simple_unlink(dir, dentry);
383 }
384
385 static const struct file_operations binder_ctl_fops = {
386 .owner = THIS_MODULE,
387 .open = nonseekable_open,
388 .unlocked_ioctl = binder_ctl_ioctl,
389 .compat_ioctl = binder_ctl_ioctl,
390 .llseek = noop_llseek,
391 };
392
393 /**
394 * binderfs_binder_ctl_create - create a new binder-control device
395 * @sb: super block of the binderfs mount
396 *
397 * This function creates a new binder-control device node in the binderfs mount
398 * referred to by @sb.
399 *
400 * Return: 0 on success, negative errno on failure
401 */
binderfs_binder_ctl_create(struct super_block * sb)402 static int binderfs_binder_ctl_create(struct super_block *sb)
403 {
404 int minor, ret;
405 struct dentry *dentry;
406 struct binder_device *device;
407 struct inode *inode = NULL;
408 struct dentry *root = sb->s_root;
409 struct binderfs_info *info = sb->s_fs_info;
410 #if defined(CONFIG_IPC_NS)
411 bool use_reserve = (info->ipc_ns == &init_ipc_ns);
412 #else
413 bool use_reserve = true;
414 #endif
415
416 device = kzalloc(sizeof(*device), GFP_KERNEL);
417 if (!device)
418 return -ENOMEM;
419
420 /* If we have already created a binder-control node, return. */
421 if (info->control_dentry) {
422 ret = 0;
423 goto out;
424 }
425
426 ret = -ENOMEM;
427 inode = new_inode(sb);
428 if (!inode)
429 goto out;
430
431 /* Reserve a new minor number for the new device. */
432 mutex_lock(&binderfs_minors_mutex);
433 minor = ida_alloc_max(&binderfs_minors,
434 use_reserve ? BINDERFS_MAX_MINOR :
435 BINDERFS_MAX_MINOR_CAPPED,
436 GFP_KERNEL);
437 mutex_unlock(&binderfs_minors_mutex);
438 if (minor < 0) {
439 ret = minor;
440 goto out;
441 }
442
443 inode->i_ino = SECOND_INODE;
444 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
445 init_special_inode(inode, S_IFCHR | 0600,
446 MKDEV(MAJOR(binderfs_dev), minor));
447 inode->i_fop = &binder_ctl_fops;
448 inode->i_uid = info->root_uid;
449 inode->i_gid = info->root_gid;
450
451 refcount_set(&device->ref, 1);
452 device->binderfs_inode = inode;
453 device->miscdev.minor = minor;
454
455 dentry = d_alloc_name(root, "binder-control");
456 if (!dentry)
457 goto out;
458
459 inode->i_private = device;
460 info->control_dentry = dentry;
461 d_add(dentry, inode);
462
463 return 0;
464
465 out:
466 kfree(device);
467 iput(inode);
468
469 return ret;
470 }
471
472 static const struct inode_operations binderfs_dir_inode_operations = {
473 .lookup = simple_lookup,
474 .rename = binderfs_rename,
475 .unlink = binderfs_unlink,
476 };
477
binderfs_make_inode(struct super_block * sb,int mode)478 static struct inode *binderfs_make_inode(struct super_block *sb, int mode)
479 {
480 struct inode *ret;
481
482 ret = new_inode(sb);
483 if (ret) {
484 ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET);
485 ret->i_mode = mode;
486 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
487 }
488 return ret;
489 }
490
binderfs_create_dentry(struct dentry * parent,const char * name)491 static struct dentry *binderfs_create_dentry(struct dentry *parent,
492 const char *name)
493 {
494 struct dentry *dentry;
495
496 dentry = lookup_one_len(name, parent, strlen(name));
497 if (IS_ERR(dentry))
498 return dentry;
499
500 /* Return error if the file/dir already exists. */
501 if (d_really_is_positive(dentry)) {
502 dput(dentry);
503 return ERR_PTR(-EEXIST);
504 }
505
506 return dentry;
507 }
508
binderfs_remove_file(struct dentry * dentry)509 void binderfs_remove_file(struct dentry *dentry)
510 {
511 struct inode *parent_inode;
512
513 parent_inode = d_inode(dentry->d_parent);
514 inode_lock(parent_inode);
515 if (simple_positive(dentry)) {
516 dget(dentry);
517 simple_unlink(parent_inode, dentry);
518 d_delete(dentry);
519 dput(dentry);
520 }
521 inode_unlock(parent_inode);
522 }
523
binderfs_create_file(struct dentry * parent,const char * name,const struct file_operations * fops,void * data)524 struct dentry *binderfs_create_file(struct dentry *parent, const char *name,
525 const struct file_operations *fops,
526 void *data)
527 {
528 struct dentry *dentry;
529 struct inode *new_inode, *parent_inode;
530 struct super_block *sb;
531
532 parent_inode = d_inode(parent);
533 inode_lock(parent_inode);
534
535 dentry = binderfs_create_dentry(parent, name);
536 if (IS_ERR(dentry))
537 goto out;
538
539 sb = parent_inode->i_sb;
540 new_inode = binderfs_make_inode(sb, S_IFREG | 0444);
541 if (!new_inode) {
542 dput(dentry);
543 dentry = ERR_PTR(-ENOMEM);
544 goto out;
545 }
546
547 new_inode->i_fop = fops;
548 new_inode->i_private = data;
549 d_instantiate(dentry, new_inode);
550 fsnotify_create(parent_inode, dentry);
551
552 out:
553 inode_unlock(parent_inode);
554 return dentry;
555 }
556
binderfs_create_dir(struct dentry * parent,const char * name)557 static struct dentry *binderfs_create_dir(struct dentry *parent,
558 const char *name)
559 {
560 struct dentry *dentry;
561 struct inode *new_inode, *parent_inode;
562 struct super_block *sb;
563
564 parent_inode = d_inode(parent);
565 inode_lock(parent_inode);
566
567 dentry = binderfs_create_dentry(parent, name);
568 if (IS_ERR(dentry))
569 goto out;
570
571 sb = parent_inode->i_sb;
572 new_inode = binderfs_make_inode(sb, S_IFDIR | 0755);
573 if (!new_inode) {
574 dput(dentry);
575 dentry = ERR_PTR(-ENOMEM);
576 goto out;
577 }
578
579 new_inode->i_fop = &simple_dir_operations;
580 new_inode->i_op = &simple_dir_inode_operations;
581
582 set_nlink(new_inode, 2);
583 d_instantiate(dentry, new_inode);
584 inc_nlink(parent_inode);
585 fsnotify_mkdir(parent_inode, dentry);
586
587 out:
588 inode_unlock(parent_inode);
589 return dentry;
590 }
591
binder_features_show(struct seq_file * m,void * unused)592 static int binder_features_show(struct seq_file *m, void *unused)
593 {
594 bool *feature = m->private;
595
596 seq_printf(m, "%d\n", *feature);
597
598 return 0;
599 }
600 DEFINE_SHOW_ATTRIBUTE(binder_features);
601
init_binder_features(struct super_block * sb)602 static int init_binder_features(struct super_block *sb)
603 {
604 struct dentry *dentry, *dir;
605
606 dir = binderfs_create_dir(sb->s_root, "features");
607 if (IS_ERR(dir))
608 return PTR_ERR(dir);
609
610 dentry = binderfs_create_file(dir, "oneway_spam_detection",
611 &binder_features_fops,
612 &binder_features.oneway_spam_detection);
613 if (IS_ERR(dentry))
614 return PTR_ERR(dentry);
615
616 return 0;
617 }
618
init_binder_logs(struct super_block * sb)619 static int init_binder_logs(struct super_block *sb)
620 {
621 struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir;
622 const struct binder_debugfs_entry *db_entry;
623 struct binderfs_info *info;
624 int ret = 0;
625
626 binder_logs_root_dir = binderfs_create_dir(sb->s_root,
627 "binder_logs");
628 if (IS_ERR(binder_logs_root_dir)) {
629 ret = PTR_ERR(binder_logs_root_dir);
630 goto out;
631 }
632
633 binder_for_each_debugfs_entry(db_entry) {
634 dentry = binderfs_create_file(binder_logs_root_dir,
635 db_entry->name,
636 db_entry->fops,
637 db_entry->data);
638 if (IS_ERR(dentry)) {
639 ret = PTR_ERR(dentry);
640 goto out;
641 }
642 }
643
644 proc_log_dir = binderfs_create_dir(binder_logs_root_dir, "proc");
645 if (IS_ERR(proc_log_dir)) {
646 ret = PTR_ERR(proc_log_dir);
647 goto out;
648 }
649 info = sb->s_fs_info;
650 info->proc_log_dir = proc_log_dir;
651
652 out:
653 return ret;
654 }
655
binderfs_fill_super(struct super_block * sb,struct fs_context * fc)656 static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
657 {
658 int ret;
659 struct binderfs_info *info;
660 struct binderfs_mount_opts *ctx = fc->fs_private;
661 struct inode *inode = NULL;
662 struct binderfs_device device_info = {};
663 const char *name;
664 size_t len;
665
666 sb->s_blocksize = PAGE_SIZE;
667 sb->s_blocksize_bits = PAGE_SHIFT;
668
669 /*
670 * The binderfs filesystem can be mounted by userns root in a
671 * non-initial userns. By default such mounts have the SB_I_NODEV flag
672 * set in s_iflags to prevent security issues where userns root can
673 * just create random device nodes via mknod() since it owns the
674 * filesystem mount. But binderfs does not allow to create any files
675 * including devices nodes. The only way to create binder devices nodes
676 * is through the binder-control device which userns root is explicitly
677 * allowed to do. So removing the SB_I_NODEV flag from s_iflags is both
678 * necessary and safe.
679 */
680 sb->s_iflags &= ~SB_I_NODEV;
681 sb->s_iflags |= SB_I_NOEXEC;
682 sb->s_magic = BINDERFS_SUPER_MAGIC;
683 sb->s_op = &binderfs_super_ops;
684 sb->s_time_gran = 1;
685
686 sb->s_fs_info = kzalloc(sizeof(struct binderfs_info), GFP_KERNEL);
687 if (!sb->s_fs_info)
688 return -ENOMEM;
689 info = sb->s_fs_info;
690
691 info->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns);
692
693 info->root_gid = make_kgid(sb->s_user_ns, 0);
694 if (!gid_valid(info->root_gid))
695 info->root_gid = GLOBAL_ROOT_GID;
696 info->root_uid = make_kuid(sb->s_user_ns, 0);
697 if (!uid_valid(info->root_uid))
698 info->root_uid = GLOBAL_ROOT_UID;
699 info->mount_opts.max = ctx->max;
700 info->mount_opts.stats_mode = ctx->stats_mode;
701
702 inode = new_inode(sb);
703 if (!inode)
704 return -ENOMEM;
705
706 inode->i_ino = FIRST_INODE;
707 inode->i_fop = &simple_dir_operations;
708 inode->i_mode = S_IFDIR | 0755;
709 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
710 inode->i_op = &binderfs_dir_inode_operations;
711 set_nlink(inode, 2);
712
713 sb->s_root = d_make_root(inode);
714 if (!sb->s_root)
715 return -ENOMEM;
716
717 ret = binderfs_binder_ctl_create(sb);
718 if (ret)
719 return ret;
720
721 name = binder_devices_param;
722 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
723 strscpy(device_info.name, name, len + 1);
724 ret = binderfs_binder_device_create(inode, NULL, &device_info);
725 if (ret)
726 return ret;
727 name += len;
728 if (*name == ',')
729 name++;
730 }
731
732 ret = init_binder_features(sb);
733 if (ret)
734 return ret;
735
736 if (info->mount_opts.stats_mode == binderfs_stats_mode_global)
737 return init_binder_logs(sb);
738
739 return 0;
740 }
741
binderfs_fs_context_get_tree(struct fs_context * fc)742 static int binderfs_fs_context_get_tree(struct fs_context *fc)
743 {
744 return get_tree_nodev(fc, binderfs_fill_super);
745 }
746
binderfs_fs_context_free(struct fs_context * fc)747 static void binderfs_fs_context_free(struct fs_context *fc)
748 {
749 struct binderfs_mount_opts *ctx = fc->fs_private;
750
751 kfree(ctx);
752 }
753
754 static const struct fs_context_operations binderfs_fs_context_ops = {
755 .free = binderfs_fs_context_free,
756 .get_tree = binderfs_fs_context_get_tree,
757 .parse_param = binderfs_fs_context_parse_param,
758 .reconfigure = binderfs_fs_context_reconfigure,
759 };
760
binderfs_init_fs_context(struct fs_context * fc)761 static int binderfs_init_fs_context(struct fs_context *fc)
762 {
763 struct binderfs_mount_opts *ctx;
764
765 ctx = kzalloc(sizeof(struct binderfs_mount_opts), GFP_KERNEL);
766 if (!ctx)
767 return -ENOMEM;
768
769 ctx->max = BINDERFS_MAX_MINOR;
770 ctx->stats_mode = binderfs_stats_mode_unset;
771
772 fc->fs_private = ctx;
773 fc->ops = &binderfs_fs_context_ops;
774
775 return 0;
776 }
777
778 static struct file_system_type binder_fs_type = {
779 .name = "binder",
780 .init_fs_context = binderfs_init_fs_context,
781 .parameters = binderfs_fs_parameters,
782 .kill_sb = kill_litter_super,
783 .fs_flags = FS_USERNS_MOUNT,
784 };
785
init_binderfs(void)786 int __init init_binderfs(void)
787 {
788 int ret;
789 const char *name;
790 size_t len;
791
792 /* Verify that the default binderfs device names are valid. */
793 name = binder_devices_param;
794 for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
795 if (len > BINDERFS_MAX_NAME)
796 return -E2BIG;
797 name += len;
798 if (*name == ',')
799 name++;
800 }
801
802 /* Allocate new major number for binderfs. */
803 ret = alloc_chrdev_region(&binderfs_dev, 0, BINDERFS_MAX_MINOR,
804 "binder");
805 if (ret)
806 return ret;
807
808 ret = register_filesystem(&binder_fs_type);
809 if (ret) {
810 unregister_chrdev_region(binderfs_dev, BINDERFS_MAX_MINOR);
811 return ret;
812 }
813
814 return ret;
815 }
816