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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/proc/inode.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8#include <linux/cache.h>
9#include <linux/time.h>
10#include <linux/proc_fs.h>
11#include <linux/kernel.h>
12#include <linux/pid_namespace.h>
13#include <linux/mm.h>
14#include <linux/string.h>
15#include <linux/stat.h>
16#include <linux/completion.h>
17#include <linux/poll.h>
18#include <linux/printk.h>
19#include <linux/file.h>
20#include <linux/limits.h>
21#include <linux/init.h>
22#include <linux/module.h>
23#include <linux/sysctl.h>
24#include <linux/seq_file.h>
25#include <linux/slab.h>
26#include <linux/mount.h>
27#include <linux/bug.h>
28
29#include "internal.h"
30
31static void proc_evict_inode(struct inode *inode)
32{
33 struct proc_dir_entry *de;
34 struct ctl_table_header *head;
35 struct proc_inode *ei = PROC_I(inode);
36
37 truncate_inode_pages_final(&inode->i_data);
38 clear_inode(inode);
39
40 /* Stop tracking associated processes */
41 if (ei->pid) {
42 proc_pid_evict_inode(ei);
43 ei->pid = NULL;
44 }
45
46 /* Let go of any associated proc directory entry */
47 de = ei->pde;
48 if (de) {
49 pde_put(de);
50 ei->pde = NULL;
51 }
52
53 head = ei->sysctl;
54 if (head) {
55 RCU_INIT_POINTER(ei->sysctl, NULL);
56 proc_sys_evict_inode(inode, head);
57 }
58}
59
60static struct kmem_cache *proc_inode_cachep __ro_after_init;
61static struct kmem_cache *pde_opener_cache __ro_after_init;
62
63static struct inode *proc_alloc_inode(struct super_block *sb)
64{
65 struct proc_inode *ei;
66
67 ei = alloc_inode_sb(sb, proc_inode_cachep, GFP_KERNEL);
68 if (!ei)
69 return NULL;
70 ei->pid = NULL;
71 ei->fd = 0;
72 ei->op.proc_get_link = NULL;
73 ei->pde = NULL;
74 ei->sysctl = NULL;
75 ei->sysctl_entry = NULL;
76 INIT_HLIST_NODE(&ei->sibling_inodes);
77 ei->ns_ops = NULL;
78 return &ei->vfs_inode;
79}
80
81static void proc_free_inode(struct inode *inode)
82{
83 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
84}
85
86static void init_once(void *foo)
87{
88 struct proc_inode *ei = (struct proc_inode *) foo;
89
90 inode_init_once(&ei->vfs_inode);
91}
92
93void __init proc_init_kmemcache(void)
94{
95 proc_inode_cachep = kmem_cache_create("proc_inode_cache",
96 sizeof(struct proc_inode),
97 0, (SLAB_RECLAIM_ACCOUNT|
98 SLAB_MEM_SPREAD|SLAB_ACCOUNT|
99 SLAB_PANIC),
100 init_once);
101 pde_opener_cache =
102 kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
103 SLAB_ACCOUNT|SLAB_PANIC, NULL);
104 proc_dir_entry_cache = kmem_cache_create_usercopy(
105 "proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
106 offsetof(struct proc_dir_entry, inline_name),
107 SIZEOF_PDE_INLINE_NAME, NULL);
108 BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
109}
110
111void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock)
112{
113 struct inode *inode;
114 struct proc_inode *ei;
115 struct hlist_node *node;
116 struct super_block *old_sb = NULL;
117
118 rcu_read_lock();
119 for (;;) {
120 struct super_block *sb;
121 node = hlist_first_rcu(inodes);
122 if (!node)
123 break;
124 ei = hlist_entry(node, struct proc_inode, sibling_inodes);
125 spin_lock(lock);
126 hlist_del_init_rcu(&ei->sibling_inodes);
127 spin_unlock(lock);
128
129 inode = &ei->vfs_inode;
130 sb = inode->i_sb;
131 if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active))
132 continue;
133 inode = igrab(inode);
134 rcu_read_unlock();
135 if (sb != old_sb) {
136 if (old_sb)
137 deactivate_super(old_sb);
138 old_sb = sb;
139 }
140 if (unlikely(!inode)) {
141 rcu_read_lock();
142 continue;
143 }
144
145 if (S_ISDIR(inode->i_mode)) {
146 struct dentry *dir = d_find_any_alias(inode);
147 if (dir) {
148 d_invalidate(dir);
149 dput(dir);
150 }
151 } else {
152 struct dentry *dentry;
153 while ((dentry = d_find_alias(inode))) {
154 d_invalidate(dentry);
155 dput(dentry);
156 }
157 }
158 iput(inode);
159
160 rcu_read_lock();
161 }
162 rcu_read_unlock();
163 if (old_sb)
164 deactivate_super(old_sb);
165}
166
167static inline const char *hidepid2str(enum proc_hidepid v)
168{
169 switch (v) {
170 case HIDEPID_OFF: return "off";
171 case HIDEPID_NO_ACCESS: return "noaccess";
172 case HIDEPID_INVISIBLE: return "invisible";
173 case HIDEPID_NOT_PTRACEABLE: return "ptraceable";
174 }
175 WARN_ONCE(1, "bad hide_pid value: %d\n", v);
176 return "unknown";
177}
178
179static int proc_show_options(struct seq_file *seq, struct dentry *root)
180{
181 struct proc_fs_info *fs_info = proc_sb_info(root->d_sb);
182
183 if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID))
184 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));
185 if (fs_info->hide_pid != HIDEPID_OFF)
186 seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid));
187 if (fs_info->pidonly != PROC_PIDONLY_OFF)
188 seq_printf(seq, ",subset=pid");
189
190 return 0;
191}
192
193const struct super_operations proc_sops = {
194 .alloc_inode = proc_alloc_inode,
195 .free_inode = proc_free_inode,
196 .drop_inode = generic_delete_inode,
197 .evict_inode = proc_evict_inode,
198 .statfs = simple_statfs,
199 .show_options = proc_show_options,
200};
201
202enum {BIAS = -1U<<31};
203
204static inline int use_pde(struct proc_dir_entry *pde)
205{
206 return likely(atomic_inc_unless_negative(&pde->in_use));
207}
208
209static void unuse_pde(struct proc_dir_entry *pde)
210{
211 if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
212 complete(pde->pde_unload_completion);
213}
214
215/*
216 * At most 2 contexts can enter this function: the one doing the last
217 * close on the descriptor and whoever is deleting PDE itself.
218 *
219 * First to enter calls ->proc_release hook and signals its completion
220 * to the second one which waits and then does nothing.
221 *
222 * PDE is locked on entry, unlocked on exit.
223 */
224static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
225 __releases(&pde->pde_unload_lock)
226{
227 /*
228 * close() (proc_reg_release()) can't delete an entry and proceed:
229 * ->release hook needs to be available at the right moment.
230 *
231 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
232 * "struct file" needs to be available at the right moment.
233 */
234 if (pdeo->closing) {
235 /* somebody else is doing that, just wait */
236 DECLARE_COMPLETION_ONSTACK(c);
237 pdeo->c = &c;
238 spin_unlock(&pde->pde_unload_lock);
239 wait_for_completion(&c);
240 } else {
241 struct file *file;
242 struct completion *c;
243
244 pdeo->closing = true;
245 spin_unlock(&pde->pde_unload_lock);
246
247 file = pdeo->file;
248 pde->proc_ops->proc_release(file_inode(file), file);
249
250 spin_lock(&pde->pde_unload_lock);
251 /* Strictly after ->proc_release, see above. */
252 list_del(&pdeo->lh);
253 c = pdeo->c;
254 spin_unlock(&pde->pde_unload_lock);
255 if (unlikely(c))
256 complete(c);
257 kmem_cache_free(pde_opener_cache, pdeo);
258 }
259}
260
261void proc_entry_rundown(struct proc_dir_entry *de)
262{
263 DECLARE_COMPLETION_ONSTACK(c);
264 /* Wait until all existing callers into module are done. */
265 de->pde_unload_completion = &c;
266 if (atomic_add_return(BIAS, &de->in_use) != BIAS)
267 wait_for_completion(&c);
268
269 /* ->pde_openers list can't grow from now on. */
270
271 spin_lock(&de->pde_unload_lock);
272 while (!list_empty(&de->pde_openers)) {
273 struct pde_opener *pdeo;
274 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
275 close_pdeo(de, pdeo);
276 spin_lock(&de->pde_unload_lock);
277 }
278 spin_unlock(&de->pde_unload_lock);
279}
280
281static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
282{
283 struct proc_dir_entry *pde = PDE(file_inode(file));
284 loff_t rv = -EINVAL;
285
286 if (pde_is_permanent(pde)) {
287 return pde->proc_ops->proc_lseek(file, offset, whence);
288 } else if (use_pde(pde)) {
289 rv = pde->proc_ops->proc_lseek(file, offset, whence);
290 unuse_pde(pde);
291 }
292 return rv;
293}
294
295static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter)
296{
297 struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp));
298 ssize_t ret;
299
300 if (pde_is_permanent(pde))
301 return pde->proc_ops->proc_read_iter(iocb, iter);
302
303 if (!use_pde(pde))
304 return -EIO;
305 ret = pde->proc_ops->proc_read_iter(iocb, iter);
306 unuse_pde(pde);
307 return ret;
308}
309
310static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
311{
312 typeof_member(struct proc_ops, proc_read) read;
313
314 read = pde->proc_ops->proc_read;
315 if (read)
316 return read(file, buf, count, ppos);
317 return -EIO;
318}
319
320static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
321{
322 struct proc_dir_entry *pde = PDE(file_inode(file));
323 ssize_t rv = -EIO;
324
325 if (pde_is_permanent(pde)) {
326 return pde_read(pde, file, buf, count, ppos);
327 } else if (use_pde(pde)) {
328 rv = pde_read(pde, file, buf, count, ppos);
329 unuse_pde(pde);
330 }
331 return rv;
332}
333
334static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos)
335{
336 typeof_member(struct proc_ops, proc_write) write;
337
338 write = pde->proc_ops->proc_write;
339 if (write)
340 return write(file, buf, count, ppos);
341 return -EIO;
342}
343
344static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
345{
346 struct proc_dir_entry *pde = PDE(file_inode(file));
347 ssize_t rv = -EIO;
348
349 if (pde_is_permanent(pde)) {
350 return pde_write(pde, file, buf, count, ppos);
351 } else if (use_pde(pde)) {
352 rv = pde_write(pde, file, buf, count, ppos);
353 unuse_pde(pde);
354 }
355 return rv;
356}
357
358static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts)
359{
360 typeof_member(struct proc_ops, proc_poll) poll;
361
362 poll = pde->proc_ops->proc_poll;
363 if (poll)
364 return poll(file, pts);
365 return DEFAULT_POLLMASK;
366}
367
368static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
369{
370 struct proc_dir_entry *pde = PDE(file_inode(file));
371 __poll_t rv = DEFAULT_POLLMASK;
372
373 if (pde_is_permanent(pde)) {
374 return pde_poll(pde, file, pts);
375 } else if (use_pde(pde)) {
376 rv = pde_poll(pde, file, pts);
377 unuse_pde(pde);
378 }
379 return rv;
380}
381
382static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
383{
384 typeof_member(struct proc_ops, proc_ioctl) ioctl;
385
386 ioctl = pde->proc_ops->proc_ioctl;
387 if (ioctl)
388 return ioctl(file, cmd, arg);
389 return -ENOTTY;
390}
391
392static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
393{
394 struct proc_dir_entry *pde = PDE(file_inode(file));
395 long rv = -ENOTTY;
396
397 if (pde_is_permanent(pde)) {
398 return pde_ioctl(pde, file, cmd, arg);
399 } else if (use_pde(pde)) {
400 rv = pde_ioctl(pde, file, cmd, arg);
401 unuse_pde(pde);
402 }
403 return rv;
404}
405
406#ifdef CONFIG_COMPAT
407static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
408{
409 typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
410
411 compat_ioctl = pde->proc_ops->proc_compat_ioctl;
412 if (compat_ioctl)
413 return compat_ioctl(file, cmd, arg);
414 return -ENOTTY;
415}
416
417static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
418{
419 struct proc_dir_entry *pde = PDE(file_inode(file));
420 long rv = -ENOTTY;
421 if (pde_is_permanent(pde)) {
422 return pde_compat_ioctl(pde, file, cmd, arg);
423 } else if (use_pde(pde)) {
424 rv = pde_compat_ioctl(pde, file, cmd, arg);
425 unuse_pde(pde);
426 }
427 return rv;
428}
429#endif
430
431static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
432{
433 typeof_member(struct proc_ops, proc_mmap) mmap;
434
435 mmap = pde->proc_ops->proc_mmap;
436 if (mmap)
437 return mmap(file, vma);
438 return -EIO;
439}
440
441static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
442{
443 struct proc_dir_entry *pde = PDE(file_inode(file));
444 int rv = -EIO;
445
446 if (pde_is_permanent(pde)) {
447 return pde_mmap(pde, file, vma);
448 } else if (use_pde(pde)) {
449 rv = pde_mmap(pde, file, vma);
450 unuse_pde(pde);
451 }
452 return rv;
453}
454
455static unsigned long
456pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr,
457 unsigned long len, unsigned long pgoff,
458 unsigned long flags)
459{
460 typeof_member(struct proc_ops, proc_get_unmapped_area) get_area;
461
462 get_area = pde->proc_ops->proc_get_unmapped_area;
463#ifdef CONFIG_MMU
464 if (!get_area)
465 get_area = current->mm->get_unmapped_area;
466#endif
467 if (get_area)
468 return get_area(file, orig_addr, len, pgoff, flags);
469 return orig_addr;
470}
471
472static unsigned long
473proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
474 unsigned long len, unsigned long pgoff,
475 unsigned long flags)
476{
477 struct proc_dir_entry *pde = PDE(file_inode(file));
478 unsigned long rv = -EIO;
479
480 if (pde_is_permanent(pde)) {
481 return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
482 } else if (use_pde(pde)) {
483 rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
484 unuse_pde(pde);
485 }
486 return rv;
487}
488
489static int proc_reg_open(struct inode *inode, struct file *file)
490{
491 struct proc_dir_entry *pde = PDE(inode);
492 int rv = 0;
493 typeof_member(struct proc_ops, proc_open) open;
494 typeof_member(struct proc_ops, proc_release) release;
495 struct pde_opener *pdeo;
496
497 if (!pde->proc_ops->proc_lseek)
498 file->f_mode &= ~FMODE_LSEEK;
499
500 if (pde_is_permanent(pde)) {
501 open = pde->proc_ops->proc_open;
502 if (open)
503 rv = open(inode, file);
504 return rv;
505 }
506
507 /*
508 * Ensure that
509 * 1) PDE's ->release hook will be called no matter what
510 * either normally by close()/->release, or forcefully by
511 * rmmod/remove_proc_entry.
512 *
513 * 2) rmmod isn't blocked by opening file in /proc and sitting on
514 * the descriptor (including "rmmod foo </proc/foo" scenario).
515 *
516 * Save every "struct file" with custom ->release hook.
517 */
518 if (!use_pde(pde))
519 return -ENOENT;
520
521 release = pde->proc_ops->proc_release;
522 if (release) {
523 pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
524 if (!pdeo) {
525 rv = -ENOMEM;
526 goto out_unuse;
527 }
528 }
529
530 open = pde->proc_ops->proc_open;
531 if (open)
532 rv = open(inode, file);
533
534 if (release) {
535 if (rv == 0) {
536 /* To know what to release. */
537 pdeo->file = file;
538 pdeo->closing = false;
539 pdeo->c = NULL;
540 spin_lock(&pde->pde_unload_lock);
541 list_add(&pdeo->lh, &pde->pde_openers);
542 spin_unlock(&pde->pde_unload_lock);
543 } else
544 kmem_cache_free(pde_opener_cache, pdeo);
545 }
546
547out_unuse:
548 unuse_pde(pde);
549 return rv;
550}
551
552static int proc_reg_release(struct inode *inode, struct file *file)
553{
554 struct proc_dir_entry *pde = PDE(inode);
555 struct pde_opener *pdeo;
556
557 if (pde_is_permanent(pde)) {
558 typeof_member(struct proc_ops, proc_release) release;
559
560 release = pde->proc_ops->proc_release;
561 if (release) {
562 return release(inode, file);
563 }
564 return 0;
565 }
566
567 spin_lock(&pde->pde_unload_lock);
568 list_for_each_entry(pdeo, &pde->pde_openers, lh) {
569 if (pdeo->file == file) {
570 close_pdeo(pde, pdeo);
571 return 0;
572 }
573 }
574 spin_unlock(&pde->pde_unload_lock);
575 return 0;
576}
577
578static const struct file_operations proc_reg_file_ops = {
579 .llseek = proc_reg_llseek,
580 .read = proc_reg_read,
581 .write = proc_reg_write,
582 .poll = proc_reg_poll,
583 .unlocked_ioctl = proc_reg_unlocked_ioctl,
584 .mmap = proc_reg_mmap,
585 .get_unmapped_area = proc_reg_get_unmapped_area,
586 .open = proc_reg_open,
587 .release = proc_reg_release,
588};
589
590static const struct file_operations proc_iter_file_ops = {
591 .llseek = proc_reg_llseek,
592 .read_iter = proc_reg_read_iter,
593 .write = proc_reg_write,
594 .splice_read = generic_file_splice_read,
595 .poll = proc_reg_poll,
596 .unlocked_ioctl = proc_reg_unlocked_ioctl,
597 .mmap = proc_reg_mmap,
598 .get_unmapped_area = proc_reg_get_unmapped_area,
599 .open = proc_reg_open,
600 .release = proc_reg_release,
601};
602
603#ifdef CONFIG_COMPAT
604static const struct file_operations proc_reg_file_ops_compat = {
605 .llseek = proc_reg_llseek,
606 .read = proc_reg_read,
607 .write = proc_reg_write,
608 .poll = proc_reg_poll,
609 .unlocked_ioctl = proc_reg_unlocked_ioctl,
610 .compat_ioctl = proc_reg_compat_ioctl,
611 .mmap = proc_reg_mmap,
612 .get_unmapped_area = proc_reg_get_unmapped_area,
613 .open = proc_reg_open,
614 .release = proc_reg_release,
615};
616
617static const struct file_operations proc_iter_file_ops_compat = {
618 .llseek = proc_reg_llseek,
619 .read_iter = proc_reg_read_iter,
620 .splice_read = generic_file_splice_read,
621 .write = proc_reg_write,
622 .poll = proc_reg_poll,
623 .unlocked_ioctl = proc_reg_unlocked_ioctl,
624 .compat_ioctl = proc_reg_compat_ioctl,
625 .mmap = proc_reg_mmap,
626 .get_unmapped_area = proc_reg_get_unmapped_area,
627 .open = proc_reg_open,
628 .release = proc_reg_release,
629};
630#endif
631
632static void proc_put_link(void *p)
633{
634 unuse_pde(p);
635}
636
637static const char *proc_get_link(struct dentry *dentry,
638 struct inode *inode,
639 struct delayed_call *done)
640{
641 struct proc_dir_entry *pde = PDE(inode);
642 if (!use_pde(pde))
643 return ERR_PTR(-EINVAL);
644 set_delayed_call(done, proc_put_link, pde);
645 return pde->data;
646}
647
648const struct inode_operations proc_link_inode_operations = {
649 .get_link = proc_get_link,
650};
651
652struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
653{
654 struct inode *inode = new_inode(sb);
655
656 if (!inode) {
657 pde_put(de);
658 return NULL;
659 }
660
661 inode->i_private = de->data;
662 inode->i_ino = de->low_ino;
663 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
664 PROC_I(inode)->pde = de;
665 if (is_empty_pde(de)) {
666 make_empty_dir_inode(inode);
667 return inode;
668 }
669
670 if (de->mode) {
671 inode->i_mode = de->mode;
672 inode->i_uid = de->uid;
673 inode->i_gid = de->gid;
674 }
675 if (de->size)
676 inode->i_size = de->size;
677 if (de->nlink)
678 set_nlink(inode, de->nlink);
679
680 if (S_ISREG(inode->i_mode)) {
681 inode->i_op = de->proc_iops;
682 if (de->proc_ops->proc_read_iter)
683 inode->i_fop = &proc_iter_file_ops;
684 else
685 inode->i_fop = &proc_reg_file_ops;
686#ifdef CONFIG_COMPAT
687 if (de->proc_ops->proc_compat_ioctl) {
688 if (de->proc_ops->proc_read_iter)
689 inode->i_fop = &proc_iter_file_ops_compat;
690 else
691 inode->i_fop = &proc_reg_file_ops_compat;
692 }
693#endif
694 } else if (S_ISDIR(inode->i_mode)) {
695 inode->i_op = de->proc_iops;
696 inode->i_fop = de->proc_dir_ops;
697 } else if (S_ISLNK(inode->i_mode)) {
698 inode->i_op = de->proc_iops;
699 inode->i_fop = NULL;
700 } else {
701 BUG();
702 }
703 return inode;
704}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/proc/inode.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8#include <linux/cache.h>
9#include <linux/time.h>
10#include <linux/proc_fs.h>
11#include <linux/kernel.h>
12#include <linux/pid_namespace.h>
13#include <linux/mm.h>
14#include <linux/string.h>
15#include <linux/stat.h>
16#include <linux/completion.h>
17#include <linux/poll.h>
18#include <linux/printk.h>
19#include <linux/file.h>
20#include <linux/limits.h>
21#include <linux/init.h>
22#include <linux/module.h>
23#include <linux/sysctl.h>
24#include <linux/seq_file.h>
25#include <linux/slab.h>
26#include <linux/mount.h>
27#include <linux/bug.h>
28
29#include <linux/uaccess.h>
30
31#include "internal.h"
32
33static void proc_evict_inode(struct inode *inode)
34{
35 struct proc_dir_entry *de;
36 struct ctl_table_header *head;
37 struct proc_inode *ei = PROC_I(inode);
38
39 truncate_inode_pages_final(&inode->i_data);
40 clear_inode(inode);
41
42 /* Stop tracking associated processes */
43 if (ei->pid) {
44 proc_pid_evict_inode(ei);
45 ei->pid = NULL;
46 }
47
48 /* Let go of any associated proc directory entry */
49 de = ei->pde;
50 if (de) {
51 pde_put(de);
52 ei->pde = NULL;
53 }
54
55 head = ei->sysctl;
56 if (head) {
57 RCU_INIT_POINTER(ei->sysctl, NULL);
58 proc_sys_evict_inode(inode, head);
59 }
60}
61
62static struct kmem_cache *proc_inode_cachep __ro_after_init;
63static struct kmem_cache *pde_opener_cache __ro_after_init;
64
65static struct inode *proc_alloc_inode(struct super_block *sb)
66{
67 struct proc_inode *ei;
68
69 ei = kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
70 if (!ei)
71 return NULL;
72 ei->pid = NULL;
73 ei->fd = 0;
74 ei->op.proc_get_link = NULL;
75 ei->pde = NULL;
76 ei->sysctl = NULL;
77 ei->sysctl_entry = NULL;
78 INIT_HLIST_NODE(&ei->sibling_inodes);
79 ei->ns_ops = NULL;
80 return &ei->vfs_inode;
81}
82
83static void proc_free_inode(struct inode *inode)
84{
85 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
86}
87
88static void init_once(void *foo)
89{
90 struct proc_inode *ei = (struct proc_inode *) foo;
91
92 inode_init_once(&ei->vfs_inode);
93}
94
95void __init proc_init_kmemcache(void)
96{
97 proc_inode_cachep = kmem_cache_create("proc_inode_cache",
98 sizeof(struct proc_inode),
99 0, (SLAB_RECLAIM_ACCOUNT|
100 SLAB_MEM_SPREAD|SLAB_ACCOUNT|
101 SLAB_PANIC),
102 init_once);
103 pde_opener_cache =
104 kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
105 SLAB_ACCOUNT|SLAB_PANIC, NULL);
106 proc_dir_entry_cache = kmem_cache_create_usercopy(
107 "proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
108 offsetof(struct proc_dir_entry, inline_name),
109 SIZEOF_PDE_INLINE_NAME, NULL);
110 BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
111}
112
113void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock)
114{
115 struct inode *inode;
116 struct proc_inode *ei;
117 struct hlist_node *node;
118 struct super_block *old_sb = NULL;
119
120 rcu_read_lock();
121 for (;;) {
122 struct super_block *sb;
123 node = hlist_first_rcu(inodes);
124 if (!node)
125 break;
126 ei = hlist_entry(node, struct proc_inode, sibling_inodes);
127 spin_lock(lock);
128 hlist_del_init_rcu(&ei->sibling_inodes);
129 spin_unlock(lock);
130
131 inode = &ei->vfs_inode;
132 sb = inode->i_sb;
133 if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active))
134 continue;
135 inode = igrab(inode);
136 rcu_read_unlock();
137 if (sb != old_sb) {
138 if (old_sb)
139 deactivate_super(old_sb);
140 old_sb = sb;
141 }
142 if (unlikely(!inode)) {
143 rcu_read_lock();
144 continue;
145 }
146
147 if (S_ISDIR(inode->i_mode)) {
148 struct dentry *dir = d_find_any_alias(inode);
149 if (dir) {
150 d_invalidate(dir);
151 dput(dir);
152 }
153 } else {
154 struct dentry *dentry;
155 while ((dentry = d_find_alias(inode))) {
156 d_invalidate(dentry);
157 dput(dentry);
158 }
159 }
160 iput(inode);
161
162 rcu_read_lock();
163 }
164 rcu_read_unlock();
165 if (old_sb)
166 deactivate_super(old_sb);
167}
168
169static inline const char *hidepid2str(enum proc_hidepid v)
170{
171 switch (v) {
172 case HIDEPID_OFF: return "off";
173 case HIDEPID_NO_ACCESS: return "noaccess";
174 case HIDEPID_INVISIBLE: return "invisible";
175 case HIDEPID_NOT_PTRACEABLE: return "ptraceable";
176 }
177 WARN_ONCE(1, "bad hide_pid value: %d\n", v);
178 return "unknown";
179}
180
181static int proc_show_options(struct seq_file *seq, struct dentry *root)
182{
183 struct proc_fs_info *fs_info = proc_sb_info(root->d_sb);
184
185 if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID))
186 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));
187 if (fs_info->hide_pid != HIDEPID_OFF)
188 seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid));
189 if (fs_info->pidonly != PROC_PIDONLY_OFF)
190 seq_printf(seq, ",subset=pid");
191
192 return 0;
193}
194
195const struct super_operations proc_sops = {
196 .alloc_inode = proc_alloc_inode,
197 .free_inode = proc_free_inode,
198 .drop_inode = generic_delete_inode,
199 .evict_inode = proc_evict_inode,
200 .statfs = simple_statfs,
201 .show_options = proc_show_options,
202};
203
204enum {BIAS = -1U<<31};
205
206static inline int use_pde(struct proc_dir_entry *pde)
207{
208 return likely(atomic_inc_unless_negative(&pde->in_use));
209}
210
211static void unuse_pde(struct proc_dir_entry *pde)
212{
213 if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
214 complete(pde->pde_unload_completion);
215}
216
217/* pde is locked on entry, unlocked on exit */
218static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
219 __releases(&pde->pde_unload_lock)
220{
221 /*
222 * close() (proc_reg_release()) can't delete an entry and proceed:
223 * ->release hook needs to be available at the right moment.
224 *
225 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
226 * "struct file" needs to be available at the right moment.
227 *
228 * Therefore, first process to enter this function does ->release() and
229 * signals its completion to the other process which does nothing.
230 */
231 if (pdeo->closing) {
232 /* somebody else is doing that, just wait */
233 DECLARE_COMPLETION_ONSTACK(c);
234 pdeo->c = &c;
235 spin_unlock(&pde->pde_unload_lock);
236 wait_for_completion(&c);
237 } else {
238 struct file *file;
239 struct completion *c;
240
241 pdeo->closing = true;
242 spin_unlock(&pde->pde_unload_lock);
243 file = pdeo->file;
244 pde->proc_ops->proc_release(file_inode(file), file);
245 spin_lock(&pde->pde_unload_lock);
246 /* After ->release. */
247 list_del(&pdeo->lh);
248 c = pdeo->c;
249 spin_unlock(&pde->pde_unload_lock);
250 if (unlikely(c))
251 complete(c);
252 kmem_cache_free(pde_opener_cache, pdeo);
253 }
254}
255
256void proc_entry_rundown(struct proc_dir_entry *de)
257{
258 DECLARE_COMPLETION_ONSTACK(c);
259 /* Wait until all existing callers into module are done. */
260 de->pde_unload_completion = &c;
261 if (atomic_add_return(BIAS, &de->in_use) != BIAS)
262 wait_for_completion(&c);
263
264 /* ->pde_openers list can't grow from now on. */
265
266 spin_lock(&de->pde_unload_lock);
267 while (!list_empty(&de->pde_openers)) {
268 struct pde_opener *pdeo;
269 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
270 close_pdeo(de, pdeo);
271 spin_lock(&de->pde_unload_lock);
272 }
273 spin_unlock(&de->pde_unload_lock);
274}
275
276static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
277{
278 struct proc_dir_entry *pde = PDE(file_inode(file));
279 loff_t rv = -EINVAL;
280
281 if (pde_is_permanent(pde)) {
282 return pde->proc_ops->proc_lseek(file, offset, whence);
283 } else if (use_pde(pde)) {
284 rv = pde->proc_ops->proc_lseek(file, offset, whence);
285 unuse_pde(pde);
286 }
287 return rv;
288}
289
290static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter)
291{
292 struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp));
293 ssize_t ret;
294
295 if (pde_is_permanent(pde))
296 return pde->proc_ops->proc_read_iter(iocb, iter);
297
298 if (!use_pde(pde))
299 return -EIO;
300 ret = pde->proc_ops->proc_read_iter(iocb, iter);
301 unuse_pde(pde);
302 return ret;
303}
304
305static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
306{
307 typeof_member(struct proc_ops, proc_read) read;
308
309 read = pde->proc_ops->proc_read;
310 if (read)
311 return read(file, buf, count, ppos);
312 return -EIO;
313}
314
315static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
316{
317 struct proc_dir_entry *pde = PDE(file_inode(file));
318 ssize_t rv = -EIO;
319
320 if (pde_is_permanent(pde)) {
321 return pde_read(pde, file, buf, count, ppos);
322 } else if (use_pde(pde)) {
323 rv = pde_read(pde, file, buf, count, ppos);
324 unuse_pde(pde);
325 }
326 return rv;
327}
328
329static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos)
330{
331 typeof_member(struct proc_ops, proc_write) write;
332
333 write = pde->proc_ops->proc_write;
334 if (write)
335 return write(file, buf, count, ppos);
336 return -EIO;
337}
338
339static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
340{
341 struct proc_dir_entry *pde = PDE(file_inode(file));
342 ssize_t rv = -EIO;
343
344 if (pde_is_permanent(pde)) {
345 return pde_write(pde, file, buf, count, ppos);
346 } else if (use_pde(pde)) {
347 rv = pde_write(pde, file, buf, count, ppos);
348 unuse_pde(pde);
349 }
350 return rv;
351}
352
353static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts)
354{
355 typeof_member(struct proc_ops, proc_poll) poll;
356
357 poll = pde->proc_ops->proc_poll;
358 if (poll)
359 return poll(file, pts);
360 return DEFAULT_POLLMASK;
361}
362
363static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
364{
365 struct proc_dir_entry *pde = PDE(file_inode(file));
366 __poll_t rv = DEFAULT_POLLMASK;
367
368 if (pde_is_permanent(pde)) {
369 return pde_poll(pde, file, pts);
370 } else if (use_pde(pde)) {
371 rv = pde_poll(pde, file, pts);
372 unuse_pde(pde);
373 }
374 return rv;
375}
376
377static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
378{
379 typeof_member(struct proc_ops, proc_ioctl) ioctl;
380
381 ioctl = pde->proc_ops->proc_ioctl;
382 if (ioctl)
383 return ioctl(file, cmd, arg);
384 return -ENOTTY;
385}
386
387static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
388{
389 struct proc_dir_entry *pde = PDE(file_inode(file));
390 long rv = -ENOTTY;
391
392 if (pde_is_permanent(pde)) {
393 return pde_ioctl(pde, file, cmd, arg);
394 } else if (use_pde(pde)) {
395 rv = pde_ioctl(pde, file, cmd, arg);
396 unuse_pde(pde);
397 }
398 return rv;
399}
400
401#ifdef CONFIG_COMPAT
402static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
403{
404 typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
405
406 compat_ioctl = pde->proc_ops->proc_compat_ioctl;
407 if (compat_ioctl)
408 return compat_ioctl(file, cmd, arg);
409 return -ENOTTY;
410}
411
412static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
413{
414 struct proc_dir_entry *pde = PDE(file_inode(file));
415 long rv = -ENOTTY;
416 if (pde_is_permanent(pde)) {
417 return pde_compat_ioctl(pde, file, cmd, arg);
418 } else if (use_pde(pde)) {
419 rv = pde_compat_ioctl(pde, file, cmd, arg);
420 unuse_pde(pde);
421 }
422 return rv;
423}
424#endif
425
426static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
427{
428 typeof_member(struct proc_ops, proc_mmap) mmap;
429
430 mmap = pde->proc_ops->proc_mmap;
431 if (mmap)
432 return mmap(file, vma);
433 return -EIO;
434}
435
436static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
437{
438 struct proc_dir_entry *pde = PDE(file_inode(file));
439 int rv = -EIO;
440
441 if (pde_is_permanent(pde)) {
442 return pde_mmap(pde, file, vma);
443 } else if (use_pde(pde)) {
444 rv = pde_mmap(pde, file, vma);
445 unuse_pde(pde);
446 }
447 return rv;
448}
449
450static unsigned long
451pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr,
452 unsigned long len, unsigned long pgoff,
453 unsigned long flags)
454{
455 typeof_member(struct proc_ops, proc_get_unmapped_area) get_area;
456
457 get_area = pde->proc_ops->proc_get_unmapped_area;
458#ifdef CONFIG_MMU
459 if (!get_area)
460 get_area = current->mm->get_unmapped_area;
461#endif
462 if (get_area)
463 return get_area(file, orig_addr, len, pgoff, flags);
464 return orig_addr;
465}
466
467static unsigned long
468proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
469 unsigned long len, unsigned long pgoff,
470 unsigned long flags)
471{
472 struct proc_dir_entry *pde = PDE(file_inode(file));
473 unsigned long rv = -EIO;
474
475 if (pde_is_permanent(pde)) {
476 return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
477 } else if (use_pde(pde)) {
478 rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
479 unuse_pde(pde);
480 }
481 return rv;
482}
483
484static int proc_reg_open(struct inode *inode, struct file *file)
485{
486 struct proc_dir_entry *pde = PDE(inode);
487 int rv = 0;
488 typeof_member(struct proc_ops, proc_open) open;
489 typeof_member(struct proc_ops, proc_release) release;
490 struct pde_opener *pdeo;
491
492 if (pde_is_permanent(pde)) {
493 open = pde->proc_ops->proc_open;
494 if (open)
495 rv = open(inode, file);
496 return rv;
497 }
498
499 /*
500 * Ensure that
501 * 1) PDE's ->release hook will be called no matter what
502 * either normally by close()/->release, or forcefully by
503 * rmmod/remove_proc_entry.
504 *
505 * 2) rmmod isn't blocked by opening file in /proc and sitting on
506 * the descriptor (including "rmmod foo </proc/foo" scenario).
507 *
508 * Save every "struct file" with custom ->release hook.
509 */
510 if (!use_pde(pde))
511 return -ENOENT;
512
513 release = pde->proc_ops->proc_release;
514 if (release) {
515 pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
516 if (!pdeo) {
517 rv = -ENOMEM;
518 goto out_unuse;
519 }
520 }
521
522 open = pde->proc_ops->proc_open;
523 if (open)
524 rv = open(inode, file);
525
526 if (release) {
527 if (rv == 0) {
528 /* To know what to release. */
529 pdeo->file = file;
530 pdeo->closing = false;
531 pdeo->c = NULL;
532 spin_lock(&pde->pde_unload_lock);
533 list_add(&pdeo->lh, &pde->pde_openers);
534 spin_unlock(&pde->pde_unload_lock);
535 } else
536 kmem_cache_free(pde_opener_cache, pdeo);
537 }
538
539out_unuse:
540 unuse_pde(pde);
541 return rv;
542}
543
544static int proc_reg_release(struct inode *inode, struct file *file)
545{
546 struct proc_dir_entry *pde = PDE(inode);
547 struct pde_opener *pdeo;
548
549 if (pde_is_permanent(pde)) {
550 typeof_member(struct proc_ops, proc_release) release;
551
552 release = pde->proc_ops->proc_release;
553 if (release) {
554 return release(inode, file);
555 }
556 return 0;
557 }
558
559 spin_lock(&pde->pde_unload_lock);
560 list_for_each_entry(pdeo, &pde->pde_openers, lh) {
561 if (pdeo->file == file) {
562 close_pdeo(pde, pdeo);
563 return 0;
564 }
565 }
566 spin_unlock(&pde->pde_unload_lock);
567 return 0;
568}
569
570static const struct file_operations proc_reg_file_ops = {
571 .llseek = proc_reg_llseek,
572 .read = proc_reg_read,
573 .write = proc_reg_write,
574 .poll = proc_reg_poll,
575 .unlocked_ioctl = proc_reg_unlocked_ioctl,
576 .mmap = proc_reg_mmap,
577 .get_unmapped_area = proc_reg_get_unmapped_area,
578 .open = proc_reg_open,
579 .release = proc_reg_release,
580};
581
582static const struct file_operations proc_iter_file_ops = {
583 .llseek = proc_reg_llseek,
584 .read_iter = proc_reg_read_iter,
585 .write = proc_reg_write,
586 .splice_read = generic_file_splice_read,
587 .poll = proc_reg_poll,
588 .unlocked_ioctl = proc_reg_unlocked_ioctl,
589 .mmap = proc_reg_mmap,
590 .get_unmapped_area = proc_reg_get_unmapped_area,
591 .open = proc_reg_open,
592 .release = proc_reg_release,
593};
594
595#ifdef CONFIG_COMPAT
596static const struct file_operations proc_reg_file_ops_compat = {
597 .llseek = proc_reg_llseek,
598 .read = proc_reg_read,
599 .write = proc_reg_write,
600 .poll = proc_reg_poll,
601 .unlocked_ioctl = proc_reg_unlocked_ioctl,
602 .compat_ioctl = proc_reg_compat_ioctl,
603 .mmap = proc_reg_mmap,
604 .get_unmapped_area = proc_reg_get_unmapped_area,
605 .open = proc_reg_open,
606 .release = proc_reg_release,
607};
608
609static const struct file_operations proc_iter_file_ops_compat = {
610 .llseek = proc_reg_llseek,
611 .read_iter = proc_reg_read_iter,
612 .splice_read = generic_file_splice_read,
613 .write = proc_reg_write,
614 .poll = proc_reg_poll,
615 .unlocked_ioctl = proc_reg_unlocked_ioctl,
616 .compat_ioctl = proc_reg_compat_ioctl,
617 .mmap = proc_reg_mmap,
618 .get_unmapped_area = proc_reg_get_unmapped_area,
619 .open = proc_reg_open,
620 .release = proc_reg_release,
621};
622#endif
623
624static void proc_put_link(void *p)
625{
626 unuse_pde(p);
627}
628
629static const char *proc_get_link(struct dentry *dentry,
630 struct inode *inode,
631 struct delayed_call *done)
632{
633 struct proc_dir_entry *pde = PDE(inode);
634 if (!use_pde(pde))
635 return ERR_PTR(-EINVAL);
636 set_delayed_call(done, proc_put_link, pde);
637 return pde->data;
638}
639
640const struct inode_operations proc_link_inode_operations = {
641 .get_link = proc_get_link,
642};
643
644struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
645{
646 struct inode *inode = new_inode(sb);
647
648 if (!inode) {
649 pde_put(de);
650 return NULL;
651 }
652
653 inode->i_ino = de->low_ino;
654 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
655 PROC_I(inode)->pde = de;
656 if (is_empty_pde(de)) {
657 make_empty_dir_inode(inode);
658 return inode;
659 }
660
661 if (de->mode) {
662 inode->i_mode = de->mode;
663 inode->i_uid = de->uid;
664 inode->i_gid = de->gid;
665 }
666 if (de->size)
667 inode->i_size = de->size;
668 if (de->nlink)
669 set_nlink(inode, de->nlink);
670
671 if (S_ISREG(inode->i_mode)) {
672 inode->i_op = de->proc_iops;
673 if (de->proc_ops->proc_read_iter)
674 inode->i_fop = &proc_iter_file_ops;
675 else
676 inode->i_fop = &proc_reg_file_ops;
677#ifdef CONFIG_COMPAT
678 if (de->proc_ops->proc_compat_ioctl) {
679 if (de->proc_ops->proc_read_iter)
680 inode->i_fop = &proc_iter_file_ops_compat;
681 else
682 inode->i_fop = &proc_reg_file_ops_compat;
683 }
684#endif
685 } else if (S_ISDIR(inode->i_mode)) {
686 inode->i_op = de->proc_iops;
687 inode->i_fop = de->proc_dir_ops;
688 } else if (S_ISLNK(inode->i_mode)) {
689 inode->i_op = de->proc_iops;
690 inode->i_fop = NULL;
691 } else {
692 BUG();
693 }
694 return inode;
695}