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1/*
2 * linux/fs/fcntl.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/syscalls.h>
8#include <linux/init.h>
9#include <linux/mm.h>
10#include <linux/fs.h>
11#include <linux/file.h>
12#include <linux/fdtable.h>
13#include <linux/capability.h>
14#include <linux/dnotify.h>
15#include <linux/slab.h>
16#include <linux/module.h>
17#include <linux/pipe_fs_i.h>
18#include <linux/security.h>
19#include <linux/ptrace.h>
20#include <linux/signal.h>
21#include <linux/rcupdate.h>
22#include <linux/pid_namespace.h>
23#include <linux/user_namespace.h>
24#include <linux/shmem_fs.h>
25
26#include <asm/poll.h>
27#include <asm/siginfo.h>
28#include <linux/uaccess.h>
29
30#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
31
32static int setfl(int fd, struct file * filp, unsigned long arg)
33{
34 struct inode * inode = file_inode(filp);
35 int error = 0;
36
37 /*
38 * O_APPEND cannot be cleared if the file is marked as append-only
39 * and the file is open for write.
40 */
41 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
42 return -EPERM;
43
44 /* O_NOATIME can only be set by the owner or superuser */
45 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
46 if (!inode_owner_or_capable(inode))
47 return -EPERM;
48
49 /* required for strict SunOS emulation */
50 if (O_NONBLOCK != O_NDELAY)
51 if (arg & O_NDELAY)
52 arg |= O_NONBLOCK;
53
54 /* Pipe packetized mode is controlled by O_DIRECT flag */
55 if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) {
56 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
57 !filp->f_mapping->a_ops->direct_IO)
58 return -EINVAL;
59 }
60
61 if (filp->f_op->check_flags)
62 error = filp->f_op->check_flags(arg);
63 if (error)
64 return error;
65
66 /*
67 * ->fasync() is responsible for setting the FASYNC bit.
68 */
69 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
70 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
71 if (error < 0)
72 goto out;
73 if (error > 0)
74 error = 0;
75 }
76 spin_lock(&filp->f_lock);
77 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
78 spin_unlock(&filp->f_lock);
79
80 out:
81 return error;
82}
83
84static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
85 int force)
86{
87 write_lock_irq(&filp->f_owner.lock);
88 if (force || !filp->f_owner.pid) {
89 put_pid(filp->f_owner.pid);
90 filp->f_owner.pid = get_pid(pid);
91 filp->f_owner.pid_type = type;
92
93 if (pid) {
94 const struct cred *cred = current_cred();
95 filp->f_owner.uid = cred->uid;
96 filp->f_owner.euid = cred->euid;
97 }
98 }
99 write_unlock_irq(&filp->f_owner.lock);
100}
101
102void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
103 int force)
104{
105 security_file_set_fowner(filp);
106 f_modown(filp, pid, type, force);
107}
108EXPORT_SYMBOL(__f_setown);
109
110void f_setown(struct file *filp, unsigned long arg, int force)
111{
112 enum pid_type type;
113 struct pid *pid;
114 int who = arg;
115 type = PIDTYPE_PID;
116 if (who < 0) {
117 type = PIDTYPE_PGID;
118 who = -who;
119 }
120 rcu_read_lock();
121 pid = find_vpid(who);
122 __f_setown(filp, pid, type, force);
123 rcu_read_unlock();
124}
125EXPORT_SYMBOL(f_setown);
126
127void f_delown(struct file *filp)
128{
129 f_modown(filp, NULL, PIDTYPE_PID, 1);
130}
131
132pid_t f_getown(struct file *filp)
133{
134 pid_t pid;
135 read_lock(&filp->f_owner.lock);
136 pid = pid_vnr(filp->f_owner.pid);
137 if (filp->f_owner.pid_type == PIDTYPE_PGID)
138 pid = -pid;
139 read_unlock(&filp->f_owner.lock);
140 return pid;
141}
142
143static int f_setown_ex(struct file *filp, unsigned long arg)
144{
145 struct f_owner_ex __user *owner_p = (void __user *)arg;
146 struct f_owner_ex owner;
147 struct pid *pid;
148 int type;
149 int ret;
150
151 ret = copy_from_user(&owner, owner_p, sizeof(owner));
152 if (ret)
153 return -EFAULT;
154
155 switch (owner.type) {
156 case F_OWNER_TID:
157 type = PIDTYPE_MAX;
158 break;
159
160 case F_OWNER_PID:
161 type = PIDTYPE_PID;
162 break;
163
164 case F_OWNER_PGRP:
165 type = PIDTYPE_PGID;
166 break;
167
168 default:
169 return -EINVAL;
170 }
171
172 rcu_read_lock();
173 pid = find_vpid(owner.pid);
174 if (owner.pid && !pid)
175 ret = -ESRCH;
176 else
177 __f_setown(filp, pid, type, 1);
178 rcu_read_unlock();
179
180 return ret;
181}
182
183static int f_getown_ex(struct file *filp, unsigned long arg)
184{
185 struct f_owner_ex __user *owner_p = (void __user *)arg;
186 struct f_owner_ex owner;
187 int ret = 0;
188
189 read_lock(&filp->f_owner.lock);
190 owner.pid = pid_vnr(filp->f_owner.pid);
191 switch (filp->f_owner.pid_type) {
192 case PIDTYPE_MAX:
193 owner.type = F_OWNER_TID;
194 break;
195
196 case PIDTYPE_PID:
197 owner.type = F_OWNER_PID;
198 break;
199
200 case PIDTYPE_PGID:
201 owner.type = F_OWNER_PGRP;
202 break;
203
204 default:
205 WARN_ON(1);
206 ret = -EINVAL;
207 break;
208 }
209 read_unlock(&filp->f_owner.lock);
210
211 if (!ret) {
212 ret = copy_to_user(owner_p, &owner, sizeof(owner));
213 if (ret)
214 ret = -EFAULT;
215 }
216 return ret;
217}
218
219#ifdef CONFIG_CHECKPOINT_RESTORE
220static int f_getowner_uids(struct file *filp, unsigned long arg)
221{
222 struct user_namespace *user_ns = current_user_ns();
223 uid_t __user *dst = (void __user *)arg;
224 uid_t src[2];
225 int err;
226
227 read_lock(&filp->f_owner.lock);
228 src[0] = from_kuid(user_ns, filp->f_owner.uid);
229 src[1] = from_kuid(user_ns, filp->f_owner.euid);
230 read_unlock(&filp->f_owner.lock);
231
232 err = put_user(src[0], &dst[0]);
233 err |= put_user(src[1], &dst[1]);
234
235 return err;
236}
237#else
238static int f_getowner_uids(struct file *filp, unsigned long arg)
239{
240 return -EINVAL;
241}
242#endif
243
244static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
245 struct file *filp)
246{
247 long err = -EINVAL;
248
249 switch (cmd) {
250 case F_DUPFD:
251 err = f_dupfd(arg, filp, 0);
252 break;
253 case F_DUPFD_CLOEXEC:
254 err = f_dupfd(arg, filp, O_CLOEXEC);
255 break;
256 case F_GETFD:
257 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
258 break;
259 case F_SETFD:
260 err = 0;
261 set_close_on_exec(fd, arg & FD_CLOEXEC);
262 break;
263 case F_GETFL:
264 err = filp->f_flags;
265 break;
266 case F_SETFL:
267 err = setfl(fd, filp, arg);
268 break;
269#if BITS_PER_LONG != 32
270 /* 32-bit arches must use fcntl64() */
271 case F_OFD_GETLK:
272#endif
273 case F_GETLK:
274 err = fcntl_getlk(filp, cmd, (struct flock __user *) arg);
275 break;
276#if BITS_PER_LONG != 32
277 /* 32-bit arches must use fcntl64() */
278 case F_OFD_SETLK:
279 case F_OFD_SETLKW:
280#endif
281 /* Fallthrough */
282 case F_SETLK:
283 case F_SETLKW:
284 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
285 break;
286 case F_GETOWN:
287 /*
288 * XXX If f_owner is a process group, the
289 * negative return value will get converted
290 * into an error. Oops. If we keep the
291 * current syscall conventions, the only way
292 * to fix this will be in libc.
293 */
294 err = f_getown(filp);
295 force_successful_syscall_return();
296 break;
297 case F_SETOWN:
298 f_setown(filp, arg, 1);
299 err = 0;
300 break;
301 case F_GETOWN_EX:
302 err = f_getown_ex(filp, arg);
303 break;
304 case F_SETOWN_EX:
305 err = f_setown_ex(filp, arg);
306 break;
307 case F_GETOWNER_UIDS:
308 err = f_getowner_uids(filp, arg);
309 break;
310 case F_GETSIG:
311 err = filp->f_owner.signum;
312 break;
313 case F_SETSIG:
314 /* arg == 0 restores default behaviour. */
315 if (!valid_signal(arg)) {
316 break;
317 }
318 err = 0;
319 filp->f_owner.signum = arg;
320 break;
321 case F_GETLEASE:
322 err = fcntl_getlease(filp);
323 break;
324 case F_SETLEASE:
325 err = fcntl_setlease(fd, filp, arg);
326 break;
327 case F_NOTIFY:
328 err = fcntl_dirnotify(fd, filp, arg);
329 break;
330 case F_SETPIPE_SZ:
331 case F_GETPIPE_SZ:
332 err = pipe_fcntl(filp, cmd, arg);
333 break;
334 case F_ADD_SEALS:
335 case F_GET_SEALS:
336 err = shmem_fcntl(filp, cmd, arg);
337 break;
338 default:
339 break;
340 }
341 return err;
342}
343
344static int check_fcntl_cmd(unsigned cmd)
345{
346 switch (cmd) {
347 case F_DUPFD:
348 case F_DUPFD_CLOEXEC:
349 case F_GETFD:
350 case F_SETFD:
351 case F_GETFL:
352 return 1;
353 }
354 return 0;
355}
356
357SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
358{
359 struct fd f = fdget_raw(fd);
360 long err = -EBADF;
361
362 if (!f.file)
363 goto out;
364
365 if (unlikely(f.file->f_mode & FMODE_PATH)) {
366 if (!check_fcntl_cmd(cmd))
367 goto out1;
368 }
369
370 err = security_file_fcntl(f.file, cmd, arg);
371 if (!err)
372 err = do_fcntl(fd, cmd, arg, f.file);
373
374out1:
375 fdput(f);
376out:
377 return err;
378}
379
380#if BITS_PER_LONG == 32
381SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
382 unsigned long, arg)
383{
384 struct fd f = fdget_raw(fd);
385 long err = -EBADF;
386
387 if (!f.file)
388 goto out;
389
390 if (unlikely(f.file->f_mode & FMODE_PATH)) {
391 if (!check_fcntl_cmd(cmd))
392 goto out1;
393 }
394
395 err = security_file_fcntl(f.file, cmd, arg);
396 if (err)
397 goto out1;
398
399 switch (cmd) {
400 case F_GETLK64:
401 case F_OFD_GETLK:
402 err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg);
403 break;
404 case F_SETLK64:
405 case F_SETLKW64:
406 case F_OFD_SETLK:
407 case F_OFD_SETLKW:
408 err = fcntl_setlk64(fd, f.file, cmd,
409 (struct flock64 __user *) arg);
410 break;
411 default:
412 err = do_fcntl(fd, cmd, arg, f.file);
413 break;
414 }
415out1:
416 fdput(f);
417out:
418 return err;
419}
420#endif
421
422/* Table to convert sigio signal codes into poll band bitmaps */
423
424static const long band_table[NSIGPOLL] = {
425 POLLIN | POLLRDNORM, /* POLL_IN */
426 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
427 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
428 POLLERR, /* POLL_ERR */
429 POLLPRI | POLLRDBAND, /* POLL_PRI */
430 POLLHUP | POLLERR /* POLL_HUP */
431};
432
433static inline int sigio_perm(struct task_struct *p,
434 struct fown_struct *fown, int sig)
435{
436 const struct cred *cred;
437 int ret;
438
439 rcu_read_lock();
440 cred = __task_cred(p);
441 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
442 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
443 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
444 !security_file_send_sigiotask(p, fown, sig));
445 rcu_read_unlock();
446 return ret;
447}
448
449static void send_sigio_to_task(struct task_struct *p,
450 struct fown_struct *fown,
451 int fd, int reason, int group)
452{
453 /*
454 * F_SETSIG can change ->signum lockless in parallel, make
455 * sure we read it once and use the same value throughout.
456 */
457 int signum = ACCESS_ONCE(fown->signum);
458
459 if (!sigio_perm(p, fown, signum))
460 return;
461
462 switch (signum) {
463 siginfo_t si;
464 default:
465 /* Queue a rt signal with the appropriate fd as its
466 value. We use SI_SIGIO as the source, not
467 SI_KERNEL, since kernel signals always get
468 delivered even if we can't queue. Failure to
469 queue in this case _should_ be reported; we fall
470 back to SIGIO in that case. --sct */
471 si.si_signo = signum;
472 si.si_errno = 0;
473 si.si_code = reason;
474 /* Make sure we are called with one of the POLL_*
475 reasons, otherwise we could leak kernel stack into
476 userspace. */
477 BUG_ON((reason & __SI_MASK) != __SI_POLL);
478 if (reason - POLL_IN >= NSIGPOLL)
479 si.si_band = ~0L;
480 else
481 si.si_band = band_table[reason - POLL_IN];
482 si.si_fd = fd;
483 if (!do_send_sig_info(signum, &si, p, group))
484 break;
485 /* fall-through: fall back on the old plain SIGIO signal */
486 case 0:
487 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
488 }
489}
490
491void send_sigio(struct fown_struct *fown, int fd, int band)
492{
493 struct task_struct *p;
494 enum pid_type type;
495 struct pid *pid;
496 int group = 1;
497
498 read_lock(&fown->lock);
499
500 type = fown->pid_type;
501 if (type == PIDTYPE_MAX) {
502 group = 0;
503 type = PIDTYPE_PID;
504 }
505
506 pid = fown->pid;
507 if (!pid)
508 goto out_unlock_fown;
509
510 read_lock(&tasklist_lock);
511 do_each_pid_task(pid, type, p) {
512 send_sigio_to_task(p, fown, fd, band, group);
513 } while_each_pid_task(pid, type, p);
514 read_unlock(&tasklist_lock);
515 out_unlock_fown:
516 read_unlock(&fown->lock);
517}
518
519static void send_sigurg_to_task(struct task_struct *p,
520 struct fown_struct *fown, int group)
521{
522 if (sigio_perm(p, fown, SIGURG))
523 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
524}
525
526int send_sigurg(struct fown_struct *fown)
527{
528 struct task_struct *p;
529 enum pid_type type;
530 struct pid *pid;
531 int group = 1;
532 int ret = 0;
533
534 read_lock(&fown->lock);
535
536 type = fown->pid_type;
537 if (type == PIDTYPE_MAX) {
538 group = 0;
539 type = PIDTYPE_PID;
540 }
541
542 pid = fown->pid;
543 if (!pid)
544 goto out_unlock_fown;
545
546 ret = 1;
547
548 read_lock(&tasklist_lock);
549 do_each_pid_task(pid, type, p) {
550 send_sigurg_to_task(p, fown, group);
551 } while_each_pid_task(pid, type, p);
552 read_unlock(&tasklist_lock);
553 out_unlock_fown:
554 read_unlock(&fown->lock);
555 return ret;
556}
557
558static DEFINE_SPINLOCK(fasync_lock);
559static struct kmem_cache *fasync_cache __read_mostly;
560
561static void fasync_free_rcu(struct rcu_head *head)
562{
563 kmem_cache_free(fasync_cache,
564 container_of(head, struct fasync_struct, fa_rcu));
565}
566
567/*
568 * Remove a fasync entry. If successfully removed, return
569 * positive and clear the FASYNC flag. If no entry exists,
570 * do nothing and return 0.
571 *
572 * NOTE! It is very important that the FASYNC flag always
573 * match the state "is the filp on a fasync list".
574 *
575 */
576int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
577{
578 struct fasync_struct *fa, **fp;
579 int result = 0;
580
581 spin_lock(&filp->f_lock);
582 spin_lock(&fasync_lock);
583 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
584 if (fa->fa_file != filp)
585 continue;
586
587 spin_lock_irq(&fa->fa_lock);
588 fa->fa_file = NULL;
589 spin_unlock_irq(&fa->fa_lock);
590
591 *fp = fa->fa_next;
592 call_rcu(&fa->fa_rcu, fasync_free_rcu);
593 filp->f_flags &= ~FASYNC;
594 result = 1;
595 break;
596 }
597 spin_unlock(&fasync_lock);
598 spin_unlock(&filp->f_lock);
599 return result;
600}
601
602struct fasync_struct *fasync_alloc(void)
603{
604 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
605}
606
607/*
608 * NOTE! This can be used only for unused fasync entries:
609 * entries that actually got inserted on the fasync list
610 * need to be released by rcu - see fasync_remove_entry.
611 */
612void fasync_free(struct fasync_struct *new)
613{
614 kmem_cache_free(fasync_cache, new);
615}
616
617/*
618 * Insert a new entry into the fasync list. Return the pointer to the
619 * old one if we didn't use the new one.
620 *
621 * NOTE! It is very important that the FASYNC flag always
622 * match the state "is the filp on a fasync list".
623 */
624struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
625{
626 struct fasync_struct *fa, **fp;
627
628 spin_lock(&filp->f_lock);
629 spin_lock(&fasync_lock);
630 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
631 if (fa->fa_file != filp)
632 continue;
633
634 spin_lock_irq(&fa->fa_lock);
635 fa->fa_fd = fd;
636 spin_unlock_irq(&fa->fa_lock);
637 goto out;
638 }
639
640 spin_lock_init(&new->fa_lock);
641 new->magic = FASYNC_MAGIC;
642 new->fa_file = filp;
643 new->fa_fd = fd;
644 new->fa_next = *fapp;
645 rcu_assign_pointer(*fapp, new);
646 filp->f_flags |= FASYNC;
647
648out:
649 spin_unlock(&fasync_lock);
650 spin_unlock(&filp->f_lock);
651 return fa;
652}
653
654/*
655 * Add a fasync entry. Return negative on error, positive if
656 * added, and zero if did nothing but change an existing one.
657 */
658static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
659{
660 struct fasync_struct *new;
661
662 new = fasync_alloc();
663 if (!new)
664 return -ENOMEM;
665
666 /*
667 * fasync_insert_entry() returns the old (update) entry if
668 * it existed.
669 *
670 * So free the (unused) new entry and return 0 to let the
671 * caller know that we didn't add any new fasync entries.
672 */
673 if (fasync_insert_entry(fd, filp, fapp, new)) {
674 fasync_free(new);
675 return 0;
676 }
677
678 return 1;
679}
680
681/*
682 * fasync_helper() is used by almost all character device drivers
683 * to set up the fasync queue, and for regular files by the file
684 * lease code. It returns negative on error, 0 if it did no changes
685 * and positive if it added/deleted the entry.
686 */
687int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
688{
689 if (!on)
690 return fasync_remove_entry(filp, fapp);
691 return fasync_add_entry(fd, filp, fapp);
692}
693
694EXPORT_SYMBOL(fasync_helper);
695
696/*
697 * rcu_read_lock() is held
698 */
699static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
700{
701 while (fa) {
702 struct fown_struct *fown;
703 unsigned long flags;
704
705 if (fa->magic != FASYNC_MAGIC) {
706 printk(KERN_ERR "kill_fasync: bad magic number in "
707 "fasync_struct!\n");
708 return;
709 }
710 spin_lock_irqsave(&fa->fa_lock, flags);
711 if (fa->fa_file) {
712 fown = &fa->fa_file->f_owner;
713 /* Don't send SIGURG to processes which have not set a
714 queued signum: SIGURG has its own default signalling
715 mechanism. */
716 if (!(sig == SIGURG && fown->signum == 0))
717 send_sigio(fown, fa->fa_fd, band);
718 }
719 spin_unlock_irqrestore(&fa->fa_lock, flags);
720 fa = rcu_dereference(fa->fa_next);
721 }
722}
723
724void kill_fasync(struct fasync_struct **fp, int sig, int band)
725{
726 /* First a quick test without locking: usually
727 * the list is empty.
728 */
729 if (*fp) {
730 rcu_read_lock();
731 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
732 rcu_read_unlock();
733 }
734}
735EXPORT_SYMBOL(kill_fasync);
736
737static int __init fcntl_init(void)
738{
739 /*
740 * Please add new bits here to ensure allocation uniqueness.
741 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
742 * is defined as O_NONBLOCK on some platforms and not on others.
743 */
744 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
745 O_RDONLY | O_WRONLY | O_RDWR |
746 O_CREAT | O_EXCL | O_NOCTTY |
747 O_TRUNC | O_APPEND | /* O_NONBLOCK | */
748 __O_SYNC | O_DSYNC | FASYNC |
749 O_DIRECT | O_LARGEFILE | O_DIRECTORY |
750 O_NOFOLLOW | O_NOATIME | O_CLOEXEC |
751 __FMODE_EXEC | O_PATH | __O_TMPFILE |
752 __FMODE_NONOTIFY
753 ));
754
755 fasync_cache = kmem_cache_create("fasync_cache",
756 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
757 return 0;
758}
759
760module_init(fcntl_init)
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/fcntl.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8#include <linux/syscalls.h>
9#include <linux/init.h>
10#include <linux/mm.h>
11#include <linux/sched/task.h>
12#include <linux/fs.h>
13#include <linux/filelock.h>
14#include <linux/file.h>
15#include <linux/fdtable.h>
16#include <linux/capability.h>
17#include <linux/dnotify.h>
18#include <linux/slab.h>
19#include <linux/module.h>
20#include <linux/pipe_fs_i.h>
21#include <linux/security.h>
22#include <linux/ptrace.h>
23#include <linux/signal.h>
24#include <linux/rcupdate.h>
25#include <linux/pid_namespace.h>
26#include <linux/user_namespace.h>
27#include <linux/memfd.h>
28#include <linux/compat.h>
29#include <linux/mount.h>
30#include <linux/rw_hint.h>
31
32#include <linux/poll.h>
33#include <asm/siginfo.h>
34#include <linux/uaccess.h>
35
36#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
37
38static int setfl(int fd, struct file * filp, unsigned int arg)
39{
40 struct inode * inode = file_inode(filp);
41 int error = 0;
42
43 /*
44 * O_APPEND cannot be cleared if the file is marked as append-only
45 * and the file is open for write.
46 */
47 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
48 return -EPERM;
49
50 /* O_NOATIME can only be set by the owner or superuser */
51 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
52 if (!inode_owner_or_capable(file_mnt_idmap(filp), inode))
53 return -EPERM;
54
55 /* required for strict SunOS emulation */
56 if (O_NONBLOCK != O_NDELAY)
57 if (arg & O_NDELAY)
58 arg |= O_NONBLOCK;
59
60 /* Pipe packetized mode is controlled by O_DIRECT flag */
61 if (!S_ISFIFO(inode->i_mode) &&
62 (arg & O_DIRECT) &&
63 !(filp->f_mode & FMODE_CAN_ODIRECT))
64 return -EINVAL;
65
66 if (filp->f_op->check_flags)
67 error = filp->f_op->check_flags(arg);
68 if (error)
69 return error;
70
71 /*
72 * ->fasync() is responsible for setting the FASYNC bit.
73 */
74 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
75 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
76 if (error < 0)
77 goto out;
78 if (error > 0)
79 error = 0;
80 }
81 spin_lock(&filp->f_lock);
82 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
83 filp->f_iocb_flags = iocb_flags(filp);
84 spin_unlock(&filp->f_lock);
85
86 out:
87 return error;
88}
89
90static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
91 int force)
92{
93 write_lock_irq(&filp->f_owner.lock);
94 if (force || !filp->f_owner.pid) {
95 put_pid(filp->f_owner.pid);
96 filp->f_owner.pid = get_pid(pid);
97 filp->f_owner.pid_type = type;
98
99 if (pid) {
100 const struct cred *cred = current_cred();
101 filp->f_owner.uid = cred->uid;
102 filp->f_owner.euid = cred->euid;
103 }
104 }
105 write_unlock_irq(&filp->f_owner.lock);
106}
107
108void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
109 int force)
110{
111 security_file_set_fowner(filp);
112 f_modown(filp, pid, type, force);
113}
114EXPORT_SYMBOL(__f_setown);
115
116int f_setown(struct file *filp, int who, int force)
117{
118 enum pid_type type;
119 struct pid *pid = NULL;
120 int ret = 0;
121
122 type = PIDTYPE_TGID;
123 if (who < 0) {
124 /* avoid overflow below */
125 if (who == INT_MIN)
126 return -EINVAL;
127
128 type = PIDTYPE_PGID;
129 who = -who;
130 }
131
132 rcu_read_lock();
133 if (who) {
134 pid = find_vpid(who);
135 if (!pid)
136 ret = -ESRCH;
137 }
138
139 if (!ret)
140 __f_setown(filp, pid, type, force);
141 rcu_read_unlock();
142
143 return ret;
144}
145EXPORT_SYMBOL(f_setown);
146
147void f_delown(struct file *filp)
148{
149 f_modown(filp, NULL, PIDTYPE_TGID, 1);
150}
151
152pid_t f_getown(struct file *filp)
153{
154 pid_t pid = 0;
155
156 read_lock_irq(&filp->f_owner.lock);
157 rcu_read_lock();
158 if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type)) {
159 pid = pid_vnr(filp->f_owner.pid);
160 if (filp->f_owner.pid_type == PIDTYPE_PGID)
161 pid = -pid;
162 }
163 rcu_read_unlock();
164 read_unlock_irq(&filp->f_owner.lock);
165 return pid;
166}
167
168static int f_setown_ex(struct file *filp, unsigned long arg)
169{
170 struct f_owner_ex __user *owner_p = (void __user *)arg;
171 struct f_owner_ex owner;
172 struct pid *pid;
173 int type;
174 int ret;
175
176 ret = copy_from_user(&owner, owner_p, sizeof(owner));
177 if (ret)
178 return -EFAULT;
179
180 switch (owner.type) {
181 case F_OWNER_TID:
182 type = PIDTYPE_PID;
183 break;
184
185 case F_OWNER_PID:
186 type = PIDTYPE_TGID;
187 break;
188
189 case F_OWNER_PGRP:
190 type = PIDTYPE_PGID;
191 break;
192
193 default:
194 return -EINVAL;
195 }
196
197 rcu_read_lock();
198 pid = find_vpid(owner.pid);
199 if (owner.pid && !pid)
200 ret = -ESRCH;
201 else
202 __f_setown(filp, pid, type, 1);
203 rcu_read_unlock();
204
205 return ret;
206}
207
208static int f_getown_ex(struct file *filp, unsigned long arg)
209{
210 struct f_owner_ex __user *owner_p = (void __user *)arg;
211 struct f_owner_ex owner = {};
212 int ret = 0;
213
214 read_lock_irq(&filp->f_owner.lock);
215 rcu_read_lock();
216 if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type))
217 owner.pid = pid_vnr(filp->f_owner.pid);
218 rcu_read_unlock();
219 switch (filp->f_owner.pid_type) {
220 case PIDTYPE_PID:
221 owner.type = F_OWNER_TID;
222 break;
223
224 case PIDTYPE_TGID:
225 owner.type = F_OWNER_PID;
226 break;
227
228 case PIDTYPE_PGID:
229 owner.type = F_OWNER_PGRP;
230 break;
231
232 default:
233 WARN_ON(1);
234 ret = -EINVAL;
235 break;
236 }
237 read_unlock_irq(&filp->f_owner.lock);
238
239 if (!ret) {
240 ret = copy_to_user(owner_p, &owner, sizeof(owner));
241 if (ret)
242 ret = -EFAULT;
243 }
244 return ret;
245}
246
247#ifdef CONFIG_CHECKPOINT_RESTORE
248static int f_getowner_uids(struct file *filp, unsigned long arg)
249{
250 struct user_namespace *user_ns = current_user_ns();
251 uid_t __user *dst = (void __user *)arg;
252 uid_t src[2];
253 int err;
254
255 read_lock_irq(&filp->f_owner.lock);
256 src[0] = from_kuid(user_ns, filp->f_owner.uid);
257 src[1] = from_kuid(user_ns, filp->f_owner.euid);
258 read_unlock_irq(&filp->f_owner.lock);
259
260 err = put_user(src[0], &dst[0]);
261 err |= put_user(src[1], &dst[1]);
262
263 return err;
264}
265#else
266static int f_getowner_uids(struct file *filp, unsigned long arg)
267{
268 return -EINVAL;
269}
270#endif
271
272static bool rw_hint_valid(u64 hint)
273{
274 BUILD_BUG_ON(WRITE_LIFE_NOT_SET != RWH_WRITE_LIFE_NOT_SET);
275 BUILD_BUG_ON(WRITE_LIFE_NONE != RWH_WRITE_LIFE_NONE);
276 BUILD_BUG_ON(WRITE_LIFE_SHORT != RWH_WRITE_LIFE_SHORT);
277 BUILD_BUG_ON(WRITE_LIFE_MEDIUM != RWH_WRITE_LIFE_MEDIUM);
278 BUILD_BUG_ON(WRITE_LIFE_LONG != RWH_WRITE_LIFE_LONG);
279 BUILD_BUG_ON(WRITE_LIFE_EXTREME != RWH_WRITE_LIFE_EXTREME);
280
281 switch (hint) {
282 case RWH_WRITE_LIFE_NOT_SET:
283 case RWH_WRITE_LIFE_NONE:
284 case RWH_WRITE_LIFE_SHORT:
285 case RWH_WRITE_LIFE_MEDIUM:
286 case RWH_WRITE_LIFE_LONG:
287 case RWH_WRITE_LIFE_EXTREME:
288 return true;
289 default:
290 return false;
291 }
292}
293
294static long fcntl_get_rw_hint(struct file *file, unsigned int cmd,
295 unsigned long arg)
296{
297 struct inode *inode = file_inode(file);
298 u64 __user *argp = (u64 __user *)arg;
299 u64 hint = READ_ONCE(inode->i_write_hint);
300
301 if (copy_to_user(argp, &hint, sizeof(*argp)))
302 return -EFAULT;
303 return 0;
304}
305
306static long fcntl_set_rw_hint(struct file *file, unsigned int cmd,
307 unsigned long arg)
308{
309 struct inode *inode = file_inode(file);
310 u64 __user *argp = (u64 __user *)arg;
311 u64 hint;
312
313 if (copy_from_user(&hint, argp, sizeof(hint)))
314 return -EFAULT;
315 if (!rw_hint_valid(hint))
316 return -EINVAL;
317
318 WRITE_ONCE(inode->i_write_hint, hint);
319
320 /*
321 * file->f_mapping->host may differ from inode. As an example,
322 * blkdev_open() modifies file->f_mapping.
323 */
324 if (file->f_mapping->host != inode)
325 WRITE_ONCE(file->f_mapping->host->i_write_hint, hint);
326
327 return 0;
328}
329
330static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
331 struct file *filp)
332{
333 void __user *argp = (void __user *)arg;
334 int argi = (int)arg;
335 struct flock flock;
336 long err = -EINVAL;
337
338 switch (cmd) {
339 case F_DUPFD:
340 err = f_dupfd(argi, filp, 0);
341 break;
342 case F_DUPFD_CLOEXEC:
343 err = f_dupfd(argi, filp, O_CLOEXEC);
344 break;
345 case F_GETFD:
346 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
347 break;
348 case F_SETFD:
349 err = 0;
350 set_close_on_exec(fd, argi & FD_CLOEXEC);
351 break;
352 case F_GETFL:
353 err = filp->f_flags;
354 break;
355 case F_SETFL:
356 err = setfl(fd, filp, argi);
357 break;
358#if BITS_PER_LONG != 32
359 /* 32-bit arches must use fcntl64() */
360 case F_OFD_GETLK:
361#endif
362 case F_GETLK:
363 if (copy_from_user(&flock, argp, sizeof(flock)))
364 return -EFAULT;
365 err = fcntl_getlk(filp, cmd, &flock);
366 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
367 return -EFAULT;
368 break;
369#if BITS_PER_LONG != 32
370 /* 32-bit arches must use fcntl64() */
371 case F_OFD_SETLK:
372 case F_OFD_SETLKW:
373 fallthrough;
374#endif
375 case F_SETLK:
376 case F_SETLKW:
377 if (copy_from_user(&flock, argp, sizeof(flock)))
378 return -EFAULT;
379 err = fcntl_setlk(fd, filp, cmd, &flock);
380 break;
381 case F_GETOWN:
382 /*
383 * XXX If f_owner is a process group, the
384 * negative return value will get converted
385 * into an error. Oops. If we keep the
386 * current syscall conventions, the only way
387 * to fix this will be in libc.
388 */
389 err = f_getown(filp);
390 force_successful_syscall_return();
391 break;
392 case F_SETOWN:
393 err = f_setown(filp, argi, 1);
394 break;
395 case F_GETOWN_EX:
396 err = f_getown_ex(filp, arg);
397 break;
398 case F_SETOWN_EX:
399 err = f_setown_ex(filp, arg);
400 break;
401 case F_GETOWNER_UIDS:
402 err = f_getowner_uids(filp, arg);
403 break;
404 case F_GETSIG:
405 err = filp->f_owner.signum;
406 break;
407 case F_SETSIG:
408 /* arg == 0 restores default behaviour. */
409 if (!valid_signal(argi)) {
410 break;
411 }
412 err = 0;
413 filp->f_owner.signum = argi;
414 break;
415 case F_GETLEASE:
416 err = fcntl_getlease(filp);
417 break;
418 case F_SETLEASE:
419 err = fcntl_setlease(fd, filp, argi);
420 break;
421 case F_NOTIFY:
422 err = fcntl_dirnotify(fd, filp, argi);
423 break;
424 case F_SETPIPE_SZ:
425 case F_GETPIPE_SZ:
426 err = pipe_fcntl(filp, cmd, argi);
427 break;
428 case F_ADD_SEALS:
429 case F_GET_SEALS:
430 err = memfd_fcntl(filp, cmd, argi);
431 break;
432 case F_GET_RW_HINT:
433 err = fcntl_get_rw_hint(filp, cmd, arg);
434 break;
435 case F_SET_RW_HINT:
436 err = fcntl_set_rw_hint(filp, cmd, arg);
437 break;
438 default:
439 break;
440 }
441 return err;
442}
443
444static int check_fcntl_cmd(unsigned cmd)
445{
446 switch (cmd) {
447 case F_DUPFD:
448 case F_DUPFD_CLOEXEC:
449 case F_GETFD:
450 case F_SETFD:
451 case F_GETFL:
452 return 1;
453 }
454 return 0;
455}
456
457SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
458{
459 struct fd f = fdget_raw(fd);
460 long err = -EBADF;
461
462 if (!f.file)
463 goto out;
464
465 if (unlikely(f.file->f_mode & FMODE_PATH)) {
466 if (!check_fcntl_cmd(cmd))
467 goto out1;
468 }
469
470 err = security_file_fcntl(f.file, cmd, arg);
471 if (!err)
472 err = do_fcntl(fd, cmd, arg, f.file);
473
474out1:
475 fdput(f);
476out:
477 return err;
478}
479
480#if BITS_PER_LONG == 32
481SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
482 unsigned long, arg)
483{
484 void __user *argp = (void __user *)arg;
485 struct fd f = fdget_raw(fd);
486 struct flock64 flock;
487 long err = -EBADF;
488
489 if (!f.file)
490 goto out;
491
492 if (unlikely(f.file->f_mode & FMODE_PATH)) {
493 if (!check_fcntl_cmd(cmd))
494 goto out1;
495 }
496
497 err = security_file_fcntl(f.file, cmd, arg);
498 if (err)
499 goto out1;
500
501 switch (cmd) {
502 case F_GETLK64:
503 case F_OFD_GETLK:
504 err = -EFAULT;
505 if (copy_from_user(&flock, argp, sizeof(flock)))
506 break;
507 err = fcntl_getlk64(f.file, cmd, &flock);
508 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
509 err = -EFAULT;
510 break;
511 case F_SETLK64:
512 case F_SETLKW64:
513 case F_OFD_SETLK:
514 case F_OFD_SETLKW:
515 err = -EFAULT;
516 if (copy_from_user(&flock, argp, sizeof(flock)))
517 break;
518 err = fcntl_setlk64(fd, f.file, cmd, &flock);
519 break;
520 default:
521 err = do_fcntl(fd, cmd, arg, f.file);
522 break;
523 }
524out1:
525 fdput(f);
526out:
527 return err;
528}
529#endif
530
531#ifdef CONFIG_COMPAT
532/* careful - don't use anywhere else */
533#define copy_flock_fields(dst, src) \
534 (dst)->l_type = (src)->l_type; \
535 (dst)->l_whence = (src)->l_whence; \
536 (dst)->l_start = (src)->l_start; \
537 (dst)->l_len = (src)->l_len; \
538 (dst)->l_pid = (src)->l_pid;
539
540static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl)
541{
542 struct compat_flock fl;
543
544 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock)))
545 return -EFAULT;
546 copy_flock_fields(kfl, &fl);
547 return 0;
548}
549
550static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl)
551{
552 struct compat_flock64 fl;
553
554 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64)))
555 return -EFAULT;
556 copy_flock_fields(kfl, &fl);
557 return 0;
558}
559
560static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl)
561{
562 struct compat_flock fl;
563
564 memset(&fl, 0, sizeof(struct compat_flock));
565 copy_flock_fields(&fl, kfl);
566 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock)))
567 return -EFAULT;
568 return 0;
569}
570
571static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl)
572{
573 struct compat_flock64 fl;
574
575 BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start));
576 BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len));
577
578 memset(&fl, 0, sizeof(struct compat_flock64));
579 copy_flock_fields(&fl, kfl);
580 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
581 return -EFAULT;
582 return 0;
583}
584#undef copy_flock_fields
585
586static unsigned int
587convert_fcntl_cmd(unsigned int cmd)
588{
589 switch (cmd) {
590 case F_GETLK64:
591 return F_GETLK;
592 case F_SETLK64:
593 return F_SETLK;
594 case F_SETLKW64:
595 return F_SETLKW;
596 }
597
598 return cmd;
599}
600
601/*
602 * GETLK was successful and we need to return the data, but it needs to fit in
603 * the compat structure.
604 * l_start shouldn't be too big, unless the original start + end is greater than
605 * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
606 * -EOVERFLOW in that case. l_len could be too big, in which case we just
607 * truncate it, and only allow the app to see that part of the conflicting lock
608 * that might make sense to it anyway
609 */
610static int fixup_compat_flock(struct flock *flock)
611{
612 if (flock->l_start > COMPAT_OFF_T_MAX)
613 return -EOVERFLOW;
614 if (flock->l_len > COMPAT_OFF_T_MAX)
615 flock->l_len = COMPAT_OFF_T_MAX;
616 return 0;
617}
618
619static long do_compat_fcntl64(unsigned int fd, unsigned int cmd,
620 compat_ulong_t arg)
621{
622 struct fd f = fdget_raw(fd);
623 struct flock flock;
624 long err = -EBADF;
625
626 if (!f.file)
627 return err;
628
629 if (unlikely(f.file->f_mode & FMODE_PATH)) {
630 if (!check_fcntl_cmd(cmd))
631 goto out_put;
632 }
633
634 err = security_file_fcntl(f.file, cmd, arg);
635 if (err)
636 goto out_put;
637
638 switch (cmd) {
639 case F_GETLK:
640 err = get_compat_flock(&flock, compat_ptr(arg));
641 if (err)
642 break;
643 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
644 if (err)
645 break;
646 err = fixup_compat_flock(&flock);
647 if (!err)
648 err = put_compat_flock(&flock, compat_ptr(arg));
649 break;
650 case F_GETLK64:
651 case F_OFD_GETLK:
652 err = get_compat_flock64(&flock, compat_ptr(arg));
653 if (err)
654 break;
655 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
656 if (!err)
657 err = put_compat_flock64(&flock, compat_ptr(arg));
658 break;
659 case F_SETLK:
660 case F_SETLKW:
661 err = get_compat_flock(&flock, compat_ptr(arg));
662 if (err)
663 break;
664 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
665 break;
666 case F_SETLK64:
667 case F_SETLKW64:
668 case F_OFD_SETLK:
669 case F_OFD_SETLKW:
670 err = get_compat_flock64(&flock, compat_ptr(arg));
671 if (err)
672 break;
673 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
674 break;
675 default:
676 err = do_fcntl(fd, cmd, arg, f.file);
677 break;
678 }
679out_put:
680 fdput(f);
681 return err;
682}
683
684COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
685 compat_ulong_t, arg)
686{
687 return do_compat_fcntl64(fd, cmd, arg);
688}
689
690COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
691 compat_ulong_t, arg)
692{
693 switch (cmd) {
694 case F_GETLK64:
695 case F_SETLK64:
696 case F_SETLKW64:
697 case F_OFD_GETLK:
698 case F_OFD_SETLK:
699 case F_OFD_SETLKW:
700 return -EINVAL;
701 }
702 return do_compat_fcntl64(fd, cmd, arg);
703}
704#endif
705
706/* Table to convert sigio signal codes into poll band bitmaps */
707
708static const __poll_t band_table[NSIGPOLL] = {
709 EPOLLIN | EPOLLRDNORM, /* POLL_IN */
710 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */
711 EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */
712 EPOLLERR, /* POLL_ERR */
713 EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */
714 EPOLLHUP | EPOLLERR /* POLL_HUP */
715};
716
717static inline int sigio_perm(struct task_struct *p,
718 struct fown_struct *fown, int sig)
719{
720 const struct cred *cred;
721 int ret;
722
723 rcu_read_lock();
724 cred = __task_cred(p);
725 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
726 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
727 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
728 !security_file_send_sigiotask(p, fown, sig));
729 rcu_read_unlock();
730 return ret;
731}
732
733static void send_sigio_to_task(struct task_struct *p,
734 struct fown_struct *fown,
735 int fd, int reason, enum pid_type type)
736{
737 /*
738 * F_SETSIG can change ->signum lockless in parallel, make
739 * sure we read it once and use the same value throughout.
740 */
741 int signum = READ_ONCE(fown->signum);
742
743 if (!sigio_perm(p, fown, signum))
744 return;
745
746 switch (signum) {
747 default: {
748 kernel_siginfo_t si;
749
750 /* Queue a rt signal with the appropriate fd as its
751 value. We use SI_SIGIO as the source, not
752 SI_KERNEL, since kernel signals always get
753 delivered even if we can't queue. Failure to
754 queue in this case _should_ be reported; we fall
755 back to SIGIO in that case. --sct */
756 clear_siginfo(&si);
757 si.si_signo = signum;
758 si.si_errno = 0;
759 si.si_code = reason;
760 /*
761 * Posix definies POLL_IN and friends to be signal
762 * specific si_codes for SIG_POLL. Linux extended
763 * these si_codes to other signals in a way that is
764 * ambiguous if other signals also have signal
765 * specific si_codes. In that case use SI_SIGIO instead
766 * to remove the ambiguity.
767 */
768 if ((signum != SIGPOLL) && sig_specific_sicodes(signum))
769 si.si_code = SI_SIGIO;
770
771 /* Make sure we are called with one of the POLL_*
772 reasons, otherwise we could leak kernel stack into
773 userspace. */
774 BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL));
775 if (reason - POLL_IN >= NSIGPOLL)
776 si.si_band = ~0L;
777 else
778 si.si_band = mangle_poll(band_table[reason - POLL_IN]);
779 si.si_fd = fd;
780 if (!do_send_sig_info(signum, &si, p, type))
781 break;
782 }
783 fallthrough; /* fall back on the old plain SIGIO signal */
784 case 0:
785 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type);
786 }
787}
788
789void send_sigio(struct fown_struct *fown, int fd, int band)
790{
791 struct task_struct *p;
792 enum pid_type type;
793 unsigned long flags;
794 struct pid *pid;
795
796 read_lock_irqsave(&fown->lock, flags);
797
798 type = fown->pid_type;
799 pid = fown->pid;
800 if (!pid)
801 goto out_unlock_fown;
802
803 if (type <= PIDTYPE_TGID) {
804 rcu_read_lock();
805 p = pid_task(pid, PIDTYPE_PID);
806 if (p)
807 send_sigio_to_task(p, fown, fd, band, type);
808 rcu_read_unlock();
809 } else {
810 read_lock(&tasklist_lock);
811 do_each_pid_task(pid, type, p) {
812 send_sigio_to_task(p, fown, fd, band, type);
813 } while_each_pid_task(pid, type, p);
814 read_unlock(&tasklist_lock);
815 }
816 out_unlock_fown:
817 read_unlock_irqrestore(&fown->lock, flags);
818}
819
820static void send_sigurg_to_task(struct task_struct *p,
821 struct fown_struct *fown, enum pid_type type)
822{
823 if (sigio_perm(p, fown, SIGURG))
824 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type);
825}
826
827int send_sigurg(struct fown_struct *fown)
828{
829 struct task_struct *p;
830 enum pid_type type;
831 struct pid *pid;
832 unsigned long flags;
833 int ret = 0;
834
835 read_lock_irqsave(&fown->lock, flags);
836
837 type = fown->pid_type;
838 pid = fown->pid;
839 if (!pid)
840 goto out_unlock_fown;
841
842 ret = 1;
843
844 if (type <= PIDTYPE_TGID) {
845 rcu_read_lock();
846 p = pid_task(pid, PIDTYPE_PID);
847 if (p)
848 send_sigurg_to_task(p, fown, type);
849 rcu_read_unlock();
850 } else {
851 read_lock(&tasklist_lock);
852 do_each_pid_task(pid, type, p) {
853 send_sigurg_to_task(p, fown, type);
854 } while_each_pid_task(pid, type, p);
855 read_unlock(&tasklist_lock);
856 }
857 out_unlock_fown:
858 read_unlock_irqrestore(&fown->lock, flags);
859 return ret;
860}
861
862static DEFINE_SPINLOCK(fasync_lock);
863static struct kmem_cache *fasync_cache __ro_after_init;
864
865/*
866 * Remove a fasync entry. If successfully removed, return
867 * positive and clear the FASYNC flag. If no entry exists,
868 * do nothing and return 0.
869 *
870 * NOTE! It is very important that the FASYNC flag always
871 * match the state "is the filp on a fasync list".
872 *
873 */
874int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
875{
876 struct fasync_struct *fa, **fp;
877 int result = 0;
878
879 spin_lock(&filp->f_lock);
880 spin_lock(&fasync_lock);
881 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
882 if (fa->fa_file != filp)
883 continue;
884
885 write_lock_irq(&fa->fa_lock);
886 fa->fa_file = NULL;
887 write_unlock_irq(&fa->fa_lock);
888
889 *fp = fa->fa_next;
890 kfree_rcu(fa, fa_rcu);
891 filp->f_flags &= ~FASYNC;
892 result = 1;
893 break;
894 }
895 spin_unlock(&fasync_lock);
896 spin_unlock(&filp->f_lock);
897 return result;
898}
899
900struct fasync_struct *fasync_alloc(void)
901{
902 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
903}
904
905/*
906 * NOTE! This can be used only for unused fasync entries:
907 * entries that actually got inserted on the fasync list
908 * need to be released by rcu - see fasync_remove_entry.
909 */
910void fasync_free(struct fasync_struct *new)
911{
912 kmem_cache_free(fasync_cache, new);
913}
914
915/*
916 * Insert a new entry into the fasync list. Return the pointer to the
917 * old one if we didn't use the new one.
918 *
919 * NOTE! It is very important that the FASYNC flag always
920 * match the state "is the filp on a fasync list".
921 */
922struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
923{
924 struct fasync_struct *fa, **fp;
925
926 spin_lock(&filp->f_lock);
927 spin_lock(&fasync_lock);
928 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
929 if (fa->fa_file != filp)
930 continue;
931
932 write_lock_irq(&fa->fa_lock);
933 fa->fa_fd = fd;
934 write_unlock_irq(&fa->fa_lock);
935 goto out;
936 }
937
938 rwlock_init(&new->fa_lock);
939 new->magic = FASYNC_MAGIC;
940 new->fa_file = filp;
941 new->fa_fd = fd;
942 new->fa_next = *fapp;
943 rcu_assign_pointer(*fapp, new);
944 filp->f_flags |= FASYNC;
945
946out:
947 spin_unlock(&fasync_lock);
948 spin_unlock(&filp->f_lock);
949 return fa;
950}
951
952/*
953 * Add a fasync entry. Return negative on error, positive if
954 * added, and zero if did nothing but change an existing one.
955 */
956static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
957{
958 struct fasync_struct *new;
959
960 new = fasync_alloc();
961 if (!new)
962 return -ENOMEM;
963
964 /*
965 * fasync_insert_entry() returns the old (update) entry if
966 * it existed.
967 *
968 * So free the (unused) new entry and return 0 to let the
969 * caller know that we didn't add any new fasync entries.
970 */
971 if (fasync_insert_entry(fd, filp, fapp, new)) {
972 fasync_free(new);
973 return 0;
974 }
975
976 return 1;
977}
978
979/*
980 * fasync_helper() is used by almost all character device drivers
981 * to set up the fasync queue, and for regular files by the file
982 * lease code. It returns negative on error, 0 if it did no changes
983 * and positive if it added/deleted the entry.
984 */
985int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
986{
987 if (!on)
988 return fasync_remove_entry(filp, fapp);
989 return fasync_add_entry(fd, filp, fapp);
990}
991
992EXPORT_SYMBOL(fasync_helper);
993
994/*
995 * rcu_read_lock() is held
996 */
997static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
998{
999 while (fa) {
1000 struct fown_struct *fown;
1001 unsigned long flags;
1002
1003 if (fa->magic != FASYNC_MAGIC) {
1004 printk(KERN_ERR "kill_fasync: bad magic number in "
1005 "fasync_struct!\n");
1006 return;
1007 }
1008 read_lock_irqsave(&fa->fa_lock, flags);
1009 if (fa->fa_file) {
1010 fown = &fa->fa_file->f_owner;
1011 /* Don't send SIGURG to processes which have not set a
1012 queued signum: SIGURG has its own default signalling
1013 mechanism. */
1014 if (!(sig == SIGURG && fown->signum == 0))
1015 send_sigio(fown, fa->fa_fd, band);
1016 }
1017 read_unlock_irqrestore(&fa->fa_lock, flags);
1018 fa = rcu_dereference(fa->fa_next);
1019 }
1020}
1021
1022void kill_fasync(struct fasync_struct **fp, int sig, int band)
1023{
1024 /* First a quick test without locking: usually
1025 * the list is empty.
1026 */
1027 if (*fp) {
1028 rcu_read_lock();
1029 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
1030 rcu_read_unlock();
1031 }
1032}
1033EXPORT_SYMBOL(kill_fasync);
1034
1035static int __init fcntl_init(void)
1036{
1037 /*
1038 * Please add new bits here to ensure allocation uniqueness.
1039 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
1040 * is defined as O_NONBLOCK on some platforms and not on others.
1041 */
1042 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ !=
1043 HWEIGHT32(
1044 (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) |
1045 __FMODE_EXEC | __FMODE_NONOTIFY));
1046
1047 fasync_cache = kmem_cache_create("fasync_cache",
1048 sizeof(struct fasync_struct), 0,
1049 SLAB_PANIC | SLAB_ACCOUNT, NULL);
1050 return 0;
1051}
1052
1053module_init(fcntl_init)