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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 <asm/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(filp->f_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/*
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
25#include <asm/poll.h>
26#include <asm/siginfo.h>
27#include <asm/uaccess.h>
28
29#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
30
31static int setfl(int fd, struct file * filp, unsigned long arg)
32{
33 struct inode * inode = file_inode(filp);
34 int error = 0;
35
36 /*
37 * O_APPEND cannot be cleared if the file is marked as append-only
38 * and the file is open for write.
39 */
40 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
41 return -EPERM;
42
43 /* O_NOATIME can only be set by the owner or superuser */
44 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
45 if (!inode_owner_or_capable(inode))
46 return -EPERM;
47
48 /* required for strict SunOS emulation */
49 if (O_NONBLOCK != O_NDELAY)
50 if (arg & O_NDELAY)
51 arg |= O_NONBLOCK;
52
53 if (arg & O_DIRECT) {
54 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
55 !filp->f_mapping->a_ops->direct_IO)
56 return -EINVAL;
57 }
58
59 if (filp->f_op->check_flags)
60 error = filp->f_op->check_flags(arg);
61 if (error)
62 return error;
63
64 /*
65 * ->fasync() is responsible for setting the FASYNC bit.
66 */
67 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
68 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
69 if (error < 0)
70 goto out;
71 if (error > 0)
72 error = 0;
73 }
74 spin_lock(&filp->f_lock);
75 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
76 spin_unlock(&filp->f_lock);
77
78 out:
79 return error;
80}
81
82static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
83 int force)
84{
85 write_lock_irq(&filp->f_owner.lock);
86 if (force || !filp->f_owner.pid) {
87 put_pid(filp->f_owner.pid);
88 filp->f_owner.pid = get_pid(pid);
89 filp->f_owner.pid_type = type;
90
91 if (pid) {
92 const struct cred *cred = current_cred();
93 filp->f_owner.uid = cred->uid;
94 filp->f_owner.euid = cred->euid;
95 }
96 }
97 write_unlock_irq(&filp->f_owner.lock);
98}
99
100int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
101 int force)
102{
103 int err;
104
105 err = security_file_set_fowner(filp);
106 if (err)
107 return err;
108
109 f_modown(filp, pid, type, force);
110 return 0;
111}
112EXPORT_SYMBOL(__f_setown);
113
114int f_setown(struct file *filp, unsigned long arg, int force)
115{
116 enum pid_type type;
117 struct pid *pid;
118 int who = arg;
119 int result;
120 type = PIDTYPE_PID;
121 if (who < 0) {
122 type = PIDTYPE_PGID;
123 who = -who;
124 }
125 rcu_read_lock();
126 pid = find_vpid(who);
127 result = __f_setown(filp, pid, type, force);
128 rcu_read_unlock();
129 return result;
130}
131EXPORT_SYMBOL(f_setown);
132
133void f_delown(struct file *filp)
134{
135 f_modown(filp, NULL, PIDTYPE_PID, 1);
136}
137
138pid_t f_getown(struct file *filp)
139{
140 pid_t pid;
141 read_lock(&filp->f_owner.lock);
142 pid = pid_vnr(filp->f_owner.pid);
143 if (filp->f_owner.pid_type == PIDTYPE_PGID)
144 pid = -pid;
145 read_unlock(&filp->f_owner.lock);
146 return pid;
147}
148
149static int f_setown_ex(struct file *filp, unsigned long arg)
150{
151 struct f_owner_ex __user *owner_p = (void __user *)arg;
152 struct f_owner_ex owner;
153 struct pid *pid;
154 int type;
155 int ret;
156
157 ret = copy_from_user(&owner, owner_p, sizeof(owner));
158 if (ret)
159 return -EFAULT;
160
161 switch (owner.type) {
162 case F_OWNER_TID:
163 type = PIDTYPE_MAX;
164 break;
165
166 case F_OWNER_PID:
167 type = PIDTYPE_PID;
168 break;
169
170 case F_OWNER_PGRP:
171 type = PIDTYPE_PGID;
172 break;
173
174 default:
175 return -EINVAL;
176 }
177
178 rcu_read_lock();
179 pid = find_vpid(owner.pid);
180 if (owner.pid && !pid)
181 ret = -ESRCH;
182 else
183 ret = __f_setown(filp, pid, type, 1);
184 rcu_read_unlock();
185
186 return ret;
187}
188
189static int f_getown_ex(struct file *filp, unsigned long arg)
190{
191 struct f_owner_ex __user *owner_p = (void __user *)arg;
192 struct f_owner_ex owner;
193 int ret = 0;
194
195 read_lock(&filp->f_owner.lock);
196 owner.pid = pid_vnr(filp->f_owner.pid);
197 switch (filp->f_owner.pid_type) {
198 case PIDTYPE_MAX:
199 owner.type = F_OWNER_TID;
200 break;
201
202 case PIDTYPE_PID:
203 owner.type = F_OWNER_PID;
204 break;
205
206 case PIDTYPE_PGID:
207 owner.type = F_OWNER_PGRP;
208 break;
209
210 default:
211 WARN_ON(1);
212 ret = -EINVAL;
213 break;
214 }
215 read_unlock(&filp->f_owner.lock);
216
217 if (!ret) {
218 ret = copy_to_user(owner_p, &owner, sizeof(owner));
219 if (ret)
220 ret = -EFAULT;
221 }
222 return ret;
223}
224
225#ifdef CONFIG_CHECKPOINT_RESTORE
226static int f_getowner_uids(struct file *filp, unsigned long arg)
227{
228 struct user_namespace *user_ns = current_user_ns();
229 uid_t __user *dst = (void __user *)arg;
230 uid_t src[2];
231 int err;
232
233 read_lock(&filp->f_owner.lock);
234 src[0] = from_kuid(user_ns, filp->f_owner.uid);
235 src[1] = from_kuid(user_ns, filp->f_owner.euid);
236 read_unlock(&filp->f_owner.lock);
237
238 err = put_user(src[0], &dst[0]);
239 err |= put_user(src[1], &dst[1]);
240
241 return err;
242}
243#else
244static int f_getowner_uids(struct file *filp, unsigned long arg)
245{
246 return -EINVAL;
247}
248#endif
249
250static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
251 struct file *filp)
252{
253 long err = -EINVAL;
254
255 switch (cmd) {
256 case F_DUPFD:
257 err = f_dupfd(arg, filp, 0);
258 break;
259 case F_DUPFD_CLOEXEC:
260 err = f_dupfd(arg, filp, O_CLOEXEC);
261 break;
262 case F_GETFD:
263 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
264 break;
265 case F_SETFD:
266 err = 0;
267 set_close_on_exec(fd, arg & FD_CLOEXEC);
268 break;
269 case F_GETFL:
270 err = filp->f_flags;
271 break;
272 case F_SETFL:
273 err = setfl(fd, filp, arg);
274 break;
275#if BITS_PER_LONG != 32
276 /* 32-bit arches must use fcntl64() */
277 case F_OFD_GETLK:
278#endif
279 case F_GETLK:
280 err = fcntl_getlk(filp, cmd, (struct flock __user *) arg);
281 break;
282#if BITS_PER_LONG != 32
283 /* 32-bit arches must use fcntl64() */
284 case F_OFD_SETLK:
285 case F_OFD_SETLKW:
286#endif
287 /* Fallthrough */
288 case F_SETLK:
289 case F_SETLKW:
290 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
291 break;
292 case F_GETOWN:
293 /*
294 * XXX If f_owner is a process group, the
295 * negative return value will get converted
296 * into an error. Oops. If we keep the
297 * current syscall conventions, the only way
298 * to fix this will be in libc.
299 */
300 err = f_getown(filp);
301 force_successful_syscall_return();
302 break;
303 case F_SETOWN:
304 err = f_setown(filp, arg, 1);
305 break;
306 case F_GETOWN_EX:
307 err = f_getown_ex(filp, arg);
308 break;
309 case F_SETOWN_EX:
310 err = f_setown_ex(filp, arg);
311 break;
312 case F_GETOWNER_UIDS:
313 err = f_getowner_uids(filp, arg);
314 break;
315 case F_GETSIG:
316 err = filp->f_owner.signum;
317 break;
318 case F_SETSIG:
319 /* arg == 0 restores default behaviour. */
320 if (!valid_signal(arg)) {
321 break;
322 }
323 err = 0;
324 filp->f_owner.signum = arg;
325 break;
326 case F_GETLEASE:
327 err = fcntl_getlease(filp);
328 break;
329 case F_SETLEASE:
330 err = fcntl_setlease(fd, filp, arg);
331 break;
332 case F_NOTIFY:
333 err = fcntl_dirnotify(fd, filp, arg);
334 break;
335 case F_SETPIPE_SZ:
336 case F_GETPIPE_SZ:
337 err = pipe_fcntl(filp, cmd, arg);
338 break;
339 default:
340 break;
341 }
342 return err;
343}
344
345static int check_fcntl_cmd(unsigned cmd)
346{
347 switch (cmd) {
348 case F_DUPFD:
349 case F_DUPFD_CLOEXEC:
350 case F_GETFD:
351 case F_SETFD:
352 case F_GETFL:
353 return 1;
354 }
355 return 0;
356}
357
358SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
359{
360 struct fd f = fdget_raw(fd);
361 long err = -EBADF;
362
363 if (!f.file)
364 goto out;
365
366 if (unlikely(f.file->f_mode & FMODE_PATH)) {
367 if (!check_fcntl_cmd(cmd))
368 goto out1;
369 }
370
371 err = security_file_fcntl(f.file, cmd, arg);
372 if (!err)
373 err = do_fcntl(fd, cmd, arg, f.file);
374
375out1:
376 fdput(f);
377out:
378 return err;
379}
380
381#if BITS_PER_LONG == 32
382SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
383 unsigned long, arg)
384{
385 struct fd f = fdget_raw(fd);
386 long err = -EBADF;
387
388 if (!f.file)
389 goto out;
390
391 if (unlikely(f.file->f_mode & FMODE_PATH)) {
392 if (!check_fcntl_cmd(cmd))
393 goto out1;
394 }
395
396 err = security_file_fcntl(f.file, cmd, arg);
397 if (err)
398 goto out1;
399
400 switch (cmd) {
401 case F_GETLK64:
402 case F_OFD_GETLK:
403 err = fcntl_getlk64(f.file, cmd, (struct flock64 __user *) arg);
404 break;
405 case F_SETLK64:
406 case F_SETLKW64:
407 case F_OFD_SETLK:
408 case F_OFD_SETLKW:
409 err = fcntl_setlk64(fd, f.file, cmd,
410 (struct flock64 __user *) arg);
411 break;
412 default:
413 err = do_fcntl(fd, cmd, arg, f.file);
414 break;
415 }
416out1:
417 fdput(f);
418out:
419 return err;
420}
421#endif
422
423/* Table to convert sigio signal codes into poll band bitmaps */
424
425static const long band_table[NSIGPOLL] = {
426 POLLIN | POLLRDNORM, /* POLL_IN */
427 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
428 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
429 POLLERR, /* POLL_ERR */
430 POLLPRI | POLLRDBAND, /* POLL_PRI */
431 POLLHUP | POLLERR /* POLL_HUP */
432};
433
434static inline int sigio_perm(struct task_struct *p,
435 struct fown_struct *fown, int sig)
436{
437 const struct cred *cred;
438 int ret;
439
440 rcu_read_lock();
441 cred = __task_cred(p);
442 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
443 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
444 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
445 !security_file_send_sigiotask(p, fown, sig));
446 rcu_read_unlock();
447 return ret;
448}
449
450static void send_sigio_to_task(struct task_struct *p,
451 struct fown_struct *fown,
452 int fd, int reason, int group)
453{
454 /*
455 * F_SETSIG can change ->signum lockless in parallel, make
456 * sure we read it once and use the same value throughout.
457 */
458 int signum = ACCESS_ONCE(fown->signum);
459
460 if (!sigio_perm(p, fown, signum))
461 return;
462
463 switch (signum) {
464 siginfo_t si;
465 default:
466 /* Queue a rt signal with the appropriate fd as its
467 value. We use SI_SIGIO as the source, not
468 SI_KERNEL, since kernel signals always get
469 delivered even if we can't queue. Failure to
470 queue in this case _should_ be reported; we fall
471 back to SIGIO in that case. --sct */
472 si.si_signo = signum;
473 si.si_errno = 0;
474 si.si_code = reason;
475 /* Make sure we are called with one of the POLL_*
476 reasons, otherwise we could leak kernel stack into
477 userspace. */
478 BUG_ON((reason & __SI_MASK) != __SI_POLL);
479 if (reason - POLL_IN >= NSIGPOLL)
480 si.si_band = ~0L;
481 else
482 si.si_band = band_table[reason - POLL_IN];
483 si.si_fd = fd;
484 if (!do_send_sig_info(signum, &si, p, group))
485 break;
486 /* fall-through: fall back on the old plain SIGIO signal */
487 case 0:
488 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group);
489 }
490}
491
492void send_sigio(struct fown_struct *fown, int fd, int band)
493{
494 struct task_struct *p;
495 enum pid_type type;
496 struct pid *pid;
497 int group = 1;
498
499 read_lock(&fown->lock);
500
501 type = fown->pid_type;
502 if (type == PIDTYPE_MAX) {
503 group = 0;
504 type = PIDTYPE_PID;
505 }
506
507 pid = fown->pid;
508 if (!pid)
509 goto out_unlock_fown;
510
511 read_lock(&tasklist_lock);
512 do_each_pid_task(pid, type, p) {
513 send_sigio_to_task(p, fown, fd, band, group);
514 } while_each_pid_task(pid, type, p);
515 read_unlock(&tasklist_lock);
516 out_unlock_fown:
517 read_unlock(&fown->lock);
518}
519
520static void send_sigurg_to_task(struct task_struct *p,
521 struct fown_struct *fown, int group)
522{
523 if (sigio_perm(p, fown, SIGURG))
524 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group);
525}
526
527int send_sigurg(struct fown_struct *fown)
528{
529 struct task_struct *p;
530 enum pid_type type;
531 struct pid *pid;
532 int group = 1;
533 int ret = 0;
534
535 read_lock(&fown->lock);
536
537 type = fown->pid_type;
538 if (type == PIDTYPE_MAX) {
539 group = 0;
540 type = PIDTYPE_PID;
541 }
542
543 pid = fown->pid;
544 if (!pid)
545 goto out_unlock_fown;
546
547 ret = 1;
548
549 read_lock(&tasklist_lock);
550 do_each_pid_task(pid, type, p) {
551 send_sigurg_to_task(p, fown, group);
552 } while_each_pid_task(pid, type, p);
553 read_unlock(&tasklist_lock);
554 out_unlock_fown:
555 read_unlock(&fown->lock);
556 return ret;
557}
558
559static DEFINE_SPINLOCK(fasync_lock);
560static struct kmem_cache *fasync_cache __read_mostly;
561
562static void fasync_free_rcu(struct rcu_head *head)
563{
564 kmem_cache_free(fasync_cache,
565 container_of(head, struct fasync_struct, fa_rcu));
566}
567
568/*
569 * Remove a fasync entry. If successfully removed, return
570 * positive and clear the FASYNC flag. If no entry exists,
571 * do nothing and return 0.
572 *
573 * NOTE! It is very important that the FASYNC flag always
574 * match the state "is the filp on a fasync list".
575 *
576 */
577int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
578{
579 struct fasync_struct *fa, **fp;
580 int result = 0;
581
582 spin_lock(&filp->f_lock);
583 spin_lock(&fasync_lock);
584 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
585 if (fa->fa_file != filp)
586 continue;
587
588 spin_lock_irq(&fa->fa_lock);
589 fa->fa_file = NULL;
590 spin_unlock_irq(&fa->fa_lock);
591
592 *fp = fa->fa_next;
593 call_rcu(&fa->fa_rcu, fasync_free_rcu);
594 filp->f_flags &= ~FASYNC;
595 result = 1;
596 break;
597 }
598 spin_unlock(&fasync_lock);
599 spin_unlock(&filp->f_lock);
600 return result;
601}
602
603struct fasync_struct *fasync_alloc(void)
604{
605 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
606}
607
608/*
609 * NOTE! This can be used only for unused fasync entries:
610 * entries that actually got inserted on the fasync list
611 * need to be released by rcu - see fasync_remove_entry.
612 */
613void fasync_free(struct fasync_struct *new)
614{
615 kmem_cache_free(fasync_cache, new);
616}
617
618/*
619 * Insert a new entry into the fasync list. Return the pointer to the
620 * old one if we didn't use the new one.
621 *
622 * NOTE! It is very important that the FASYNC flag always
623 * match the state "is the filp on a fasync list".
624 */
625struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
626{
627 struct fasync_struct *fa, **fp;
628
629 spin_lock(&filp->f_lock);
630 spin_lock(&fasync_lock);
631 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
632 if (fa->fa_file != filp)
633 continue;
634
635 spin_lock_irq(&fa->fa_lock);
636 fa->fa_fd = fd;
637 spin_unlock_irq(&fa->fa_lock);
638 goto out;
639 }
640
641 spin_lock_init(&new->fa_lock);
642 new->magic = FASYNC_MAGIC;
643 new->fa_file = filp;
644 new->fa_fd = fd;
645 new->fa_next = *fapp;
646 rcu_assign_pointer(*fapp, new);
647 filp->f_flags |= FASYNC;
648
649out:
650 spin_unlock(&fasync_lock);
651 spin_unlock(&filp->f_lock);
652 return fa;
653}
654
655/*
656 * Add a fasync entry. Return negative on error, positive if
657 * added, and zero if did nothing but change an existing one.
658 */
659static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
660{
661 struct fasync_struct *new;
662
663 new = fasync_alloc();
664 if (!new)
665 return -ENOMEM;
666
667 /*
668 * fasync_insert_entry() returns the old (update) entry if
669 * it existed.
670 *
671 * So free the (unused) new entry and return 0 to let the
672 * caller know that we didn't add any new fasync entries.
673 */
674 if (fasync_insert_entry(fd, filp, fapp, new)) {
675 fasync_free(new);
676 return 0;
677 }
678
679 return 1;
680}
681
682/*
683 * fasync_helper() is used by almost all character device drivers
684 * to set up the fasync queue, and for regular files by the file
685 * lease code. It returns negative on error, 0 if it did no changes
686 * and positive if it added/deleted the entry.
687 */
688int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
689{
690 if (!on)
691 return fasync_remove_entry(filp, fapp);
692 return fasync_add_entry(fd, filp, fapp);
693}
694
695EXPORT_SYMBOL(fasync_helper);
696
697/*
698 * rcu_read_lock() is held
699 */
700static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
701{
702 while (fa) {
703 struct fown_struct *fown;
704 unsigned long flags;
705
706 if (fa->magic != FASYNC_MAGIC) {
707 printk(KERN_ERR "kill_fasync: bad magic number in "
708 "fasync_struct!\n");
709 return;
710 }
711 spin_lock_irqsave(&fa->fa_lock, flags);
712 if (fa->fa_file) {
713 fown = &fa->fa_file->f_owner;
714 /* Don't send SIGURG to processes which have not set a
715 queued signum: SIGURG has its own default signalling
716 mechanism. */
717 if (!(sig == SIGURG && fown->signum == 0))
718 send_sigio(fown, fa->fa_fd, band);
719 }
720 spin_unlock_irqrestore(&fa->fa_lock, flags);
721 fa = rcu_dereference(fa->fa_next);
722 }
723}
724
725void kill_fasync(struct fasync_struct **fp, int sig, int band)
726{
727 /* First a quick test without locking: usually
728 * the list is empty.
729 */
730 if (*fp) {
731 rcu_read_lock();
732 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
733 rcu_read_unlock();
734 }
735}
736EXPORT_SYMBOL(kill_fasync);
737
738static int __init fcntl_init(void)
739{
740 /*
741 * Please add new bits here to ensure allocation uniqueness.
742 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
743 * is defined as O_NONBLOCK on some platforms and not on others.
744 */
745 BUILD_BUG_ON(20 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32(
746 O_RDONLY | O_WRONLY | O_RDWR |
747 O_CREAT | O_EXCL | O_NOCTTY |
748 O_TRUNC | O_APPEND | /* O_NONBLOCK | */
749 __O_SYNC | O_DSYNC | FASYNC |
750 O_DIRECT | O_LARGEFILE | O_DIRECTORY |
751 O_NOFOLLOW | O_NOATIME | O_CLOEXEC |
752 __FMODE_EXEC | O_PATH | __O_TMPFILE
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)