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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/file.h>
14#include <linux/fdtable.h>
15#include <linux/capability.h>
16#include <linux/dnotify.h>
17#include <linux/slab.h>
18#include <linux/module.h>
19#include <linux/pipe_fs_i.h>
20#include <linux/security.h>
21#include <linux/ptrace.h>
22#include <linux/signal.h>
23#include <linux/rcupdate.h>
24#include <linux/pid_namespace.h>
25#include <linux/user_namespace.h>
26#include <linux/memfd.h>
27#include <linux/compat.h>
28
29#include <linux/poll.h>
30#include <asm/siginfo.h>
31#include <linux/uaccess.h>
32
33#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
34
35static int setfl(int fd, struct file * filp, unsigned long arg)
36{
37 struct inode * inode = file_inode(filp);
38 int error = 0;
39
40 /*
41 * O_APPEND cannot be cleared if the file is marked as append-only
42 * and the file is open for write.
43 */
44 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
45 return -EPERM;
46
47 /* O_NOATIME can only be set by the owner or superuser */
48 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
49 if (!inode_owner_or_capable(inode))
50 return -EPERM;
51
52 /* required for strict SunOS emulation */
53 if (O_NONBLOCK != O_NDELAY)
54 if (arg & O_NDELAY)
55 arg |= O_NONBLOCK;
56
57 /* Pipe packetized mode is controlled by O_DIRECT flag */
58 if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) {
59 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
60 !filp->f_mapping->a_ops->direct_IO)
61 return -EINVAL;
62 }
63
64 if (filp->f_op->check_flags)
65 error = filp->f_op->check_flags(arg);
66 if (error)
67 return error;
68
69 /*
70 * ->fasync() is responsible for setting the FASYNC bit.
71 */
72 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
73 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
74 if (error < 0)
75 goto out;
76 if (error > 0)
77 error = 0;
78 }
79 spin_lock(&filp->f_lock);
80 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
81 spin_unlock(&filp->f_lock);
82
83 out:
84 return error;
85}
86
87static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
88 int force)
89{
90 write_lock_irq(&filp->f_owner.lock);
91 if (force || !filp->f_owner.pid) {
92 put_pid(filp->f_owner.pid);
93 filp->f_owner.pid = get_pid(pid);
94 filp->f_owner.pid_type = type;
95
96 if (pid) {
97 const struct cred *cred = current_cred();
98 filp->f_owner.uid = cred->uid;
99 filp->f_owner.euid = cred->euid;
100 }
101 }
102 write_unlock_irq(&filp->f_owner.lock);
103}
104
105void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
106 int force)
107{
108 security_file_set_fowner(filp);
109 f_modown(filp, pid, type, force);
110}
111EXPORT_SYMBOL(__f_setown);
112
113int f_setown(struct file *filp, unsigned long arg, int force)
114{
115 enum pid_type type;
116 struct pid *pid = NULL;
117 int who = arg, ret = 0;
118
119 type = PIDTYPE_TGID;
120 if (who < 0) {
121 /* avoid overflow below */
122 if (who == INT_MIN)
123 return -EINVAL;
124
125 type = PIDTYPE_PGID;
126 who = -who;
127 }
128
129 rcu_read_lock();
130 if (who) {
131 pid = find_vpid(who);
132 if (!pid)
133 ret = -ESRCH;
134 }
135
136 if (!ret)
137 __f_setown(filp, pid, type, force);
138 rcu_read_unlock();
139
140 return ret;
141}
142EXPORT_SYMBOL(f_setown);
143
144void f_delown(struct file *filp)
145{
146 f_modown(filp, NULL, PIDTYPE_TGID, 1);
147}
148
149pid_t f_getown(struct file *filp)
150{
151 pid_t pid;
152 read_lock(&filp->f_owner.lock);
153 pid = pid_vnr(filp->f_owner.pid);
154 if (filp->f_owner.pid_type == PIDTYPE_PGID)
155 pid = -pid;
156 read_unlock(&filp->f_owner.lock);
157 return pid;
158}
159
160static int f_setown_ex(struct file *filp, unsigned long arg)
161{
162 struct f_owner_ex __user *owner_p = (void __user *)arg;
163 struct f_owner_ex owner;
164 struct pid *pid;
165 int type;
166 int ret;
167
168 ret = copy_from_user(&owner, owner_p, sizeof(owner));
169 if (ret)
170 return -EFAULT;
171
172 switch (owner.type) {
173 case F_OWNER_TID:
174 type = PIDTYPE_PID;
175 break;
176
177 case F_OWNER_PID:
178 type = PIDTYPE_TGID;
179 break;
180
181 case F_OWNER_PGRP:
182 type = PIDTYPE_PGID;
183 break;
184
185 default:
186 return -EINVAL;
187 }
188
189 rcu_read_lock();
190 pid = find_vpid(owner.pid);
191 if (owner.pid && !pid)
192 ret = -ESRCH;
193 else
194 __f_setown(filp, pid, type, 1);
195 rcu_read_unlock();
196
197 return ret;
198}
199
200static int f_getown_ex(struct file *filp, unsigned long arg)
201{
202 struct f_owner_ex __user *owner_p = (void __user *)arg;
203 struct f_owner_ex owner;
204 int ret = 0;
205
206 read_lock(&filp->f_owner.lock);
207 owner.pid = pid_vnr(filp->f_owner.pid);
208 switch (filp->f_owner.pid_type) {
209 case PIDTYPE_PID:
210 owner.type = F_OWNER_TID;
211 break;
212
213 case PIDTYPE_TGID:
214 owner.type = F_OWNER_PID;
215 break;
216
217 case PIDTYPE_PGID:
218 owner.type = F_OWNER_PGRP;
219 break;
220
221 default:
222 WARN_ON(1);
223 ret = -EINVAL;
224 break;
225 }
226 read_unlock(&filp->f_owner.lock);
227
228 if (!ret) {
229 ret = copy_to_user(owner_p, &owner, sizeof(owner));
230 if (ret)
231 ret = -EFAULT;
232 }
233 return ret;
234}
235
236#ifdef CONFIG_CHECKPOINT_RESTORE
237static int f_getowner_uids(struct file *filp, unsigned long arg)
238{
239 struct user_namespace *user_ns = current_user_ns();
240 uid_t __user *dst = (void __user *)arg;
241 uid_t src[2];
242 int err;
243
244 read_lock(&filp->f_owner.lock);
245 src[0] = from_kuid(user_ns, filp->f_owner.uid);
246 src[1] = from_kuid(user_ns, filp->f_owner.euid);
247 read_unlock(&filp->f_owner.lock);
248
249 err = put_user(src[0], &dst[0]);
250 err |= put_user(src[1], &dst[1]);
251
252 return err;
253}
254#else
255static int f_getowner_uids(struct file *filp, unsigned long arg)
256{
257 return -EINVAL;
258}
259#endif
260
261static bool rw_hint_valid(enum rw_hint hint)
262{
263 switch (hint) {
264 case RWH_WRITE_LIFE_NOT_SET:
265 case RWH_WRITE_LIFE_NONE:
266 case RWH_WRITE_LIFE_SHORT:
267 case RWH_WRITE_LIFE_MEDIUM:
268 case RWH_WRITE_LIFE_LONG:
269 case RWH_WRITE_LIFE_EXTREME:
270 return true;
271 default:
272 return false;
273 }
274}
275
276static long fcntl_rw_hint(struct file *file, unsigned int cmd,
277 unsigned long arg)
278{
279 struct inode *inode = file_inode(file);
280 u64 __user *argp = (u64 __user *)arg;
281 enum rw_hint hint;
282 u64 h;
283
284 switch (cmd) {
285 case F_GET_FILE_RW_HINT:
286 h = file_write_hint(file);
287 if (copy_to_user(argp, &h, sizeof(*argp)))
288 return -EFAULT;
289 return 0;
290 case F_SET_FILE_RW_HINT:
291 if (copy_from_user(&h, argp, sizeof(h)))
292 return -EFAULT;
293 hint = (enum rw_hint) h;
294 if (!rw_hint_valid(hint))
295 return -EINVAL;
296
297 spin_lock(&file->f_lock);
298 file->f_write_hint = hint;
299 spin_unlock(&file->f_lock);
300 return 0;
301 case F_GET_RW_HINT:
302 h = inode->i_write_hint;
303 if (copy_to_user(argp, &h, sizeof(*argp)))
304 return -EFAULT;
305 return 0;
306 case F_SET_RW_HINT:
307 if (copy_from_user(&h, argp, sizeof(h)))
308 return -EFAULT;
309 hint = (enum rw_hint) h;
310 if (!rw_hint_valid(hint))
311 return -EINVAL;
312
313 inode_lock(inode);
314 inode->i_write_hint = hint;
315 inode_unlock(inode);
316 return 0;
317 default:
318 return -EINVAL;
319 }
320}
321
322static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
323 struct file *filp)
324{
325 void __user *argp = (void __user *)arg;
326 struct flock flock;
327 long err = -EINVAL;
328
329 switch (cmd) {
330 case F_DUPFD:
331 err = f_dupfd(arg, filp, 0);
332 break;
333 case F_DUPFD_CLOEXEC:
334 err = f_dupfd(arg, filp, O_CLOEXEC);
335 break;
336 case F_GETFD:
337 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
338 break;
339 case F_SETFD:
340 err = 0;
341 set_close_on_exec(fd, arg & FD_CLOEXEC);
342 break;
343 case F_GETFL:
344 err = filp->f_flags;
345 break;
346 case F_SETFL:
347 err = setfl(fd, filp, arg);
348 break;
349#if BITS_PER_LONG != 32
350 /* 32-bit arches must use fcntl64() */
351 case F_OFD_GETLK:
352#endif
353 case F_GETLK:
354 if (copy_from_user(&flock, argp, sizeof(flock)))
355 return -EFAULT;
356 err = fcntl_getlk(filp, cmd, &flock);
357 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
358 return -EFAULT;
359 break;
360#if BITS_PER_LONG != 32
361 /* 32-bit arches must use fcntl64() */
362 case F_OFD_SETLK:
363 case F_OFD_SETLKW:
364#endif
365 fallthrough;
366 case F_SETLK:
367 case F_SETLKW:
368 if (copy_from_user(&flock, argp, sizeof(flock)))
369 return -EFAULT;
370 err = fcntl_setlk(fd, filp, cmd, &flock);
371 break;
372 case F_GETOWN:
373 /*
374 * XXX If f_owner is a process group, the
375 * negative return value will get converted
376 * into an error. Oops. If we keep the
377 * current syscall conventions, the only way
378 * to fix this will be in libc.
379 */
380 err = f_getown(filp);
381 force_successful_syscall_return();
382 break;
383 case F_SETOWN:
384 err = f_setown(filp, arg, 1);
385 break;
386 case F_GETOWN_EX:
387 err = f_getown_ex(filp, arg);
388 break;
389 case F_SETOWN_EX:
390 err = f_setown_ex(filp, arg);
391 break;
392 case F_GETOWNER_UIDS:
393 err = f_getowner_uids(filp, arg);
394 break;
395 case F_GETSIG:
396 err = filp->f_owner.signum;
397 break;
398 case F_SETSIG:
399 /* arg == 0 restores default behaviour. */
400 if (!valid_signal(arg)) {
401 break;
402 }
403 err = 0;
404 filp->f_owner.signum = arg;
405 break;
406 case F_GETLEASE:
407 err = fcntl_getlease(filp);
408 break;
409 case F_SETLEASE:
410 err = fcntl_setlease(fd, filp, arg);
411 break;
412 case F_NOTIFY:
413 err = fcntl_dirnotify(fd, filp, arg);
414 break;
415 case F_SETPIPE_SZ:
416 case F_GETPIPE_SZ:
417 err = pipe_fcntl(filp, cmd, arg);
418 break;
419 case F_ADD_SEALS:
420 case F_GET_SEALS:
421 err = memfd_fcntl(filp, cmd, arg);
422 break;
423 case F_GET_RW_HINT:
424 case F_SET_RW_HINT:
425 case F_GET_FILE_RW_HINT:
426 case F_SET_FILE_RW_HINT:
427 err = fcntl_rw_hint(filp, cmd, arg);
428 break;
429 default:
430 break;
431 }
432 return err;
433}
434
435static int check_fcntl_cmd(unsigned cmd)
436{
437 switch (cmd) {
438 case F_DUPFD:
439 case F_DUPFD_CLOEXEC:
440 case F_GETFD:
441 case F_SETFD:
442 case F_GETFL:
443 return 1;
444 }
445 return 0;
446}
447
448SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
449{
450 struct fd f = fdget_raw(fd);
451 long err = -EBADF;
452
453 if (!f.file)
454 goto out;
455
456 if (unlikely(f.file->f_mode & FMODE_PATH)) {
457 if (!check_fcntl_cmd(cmd))
458 goto out1;
459 }
460
461 err = security_file_fcntl(f.file, cmd, arg);
462 if (!err)
463 err = do_fcntl(fd, cmd, arg, f.file);
464
465out1:
466 fdput(f);
467out:
468 return err;
469}
470
471#if BITS_PER_LONG == 32
472SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
473 unsigned long, arg)
474{
475 void __user *argp = (void __user *)arg;
476 struct fd f = fdget_raw(fd);
477 struct flock64 flock;
478 long err = -EBADF;
479
480 if (!f.file)
481 goto out;
482
483 if (unlikely(f.file->f_mode & FMODE_PATH)) {
484 if (!check_fcntl_cmd(cmd))
485 goto out1;
486 }
487
488 err = security_file_fcntl(f.file, cmd, arg);
489 if (err)
490 goto out1;
491
492 switch (cmd) {
493 case F_GETLK64:
494 case F_OFD_GETLK:
495 err = -EFAULT;
496 if (copy_from_user(&flock, argp, sizeof(flock)))
497 break;
498 err = fcntl_getlk64(f.file, cmd, &flock);
499 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
500 err = -EFAULT;
501 break;
502 case F_SETLK64:
503 case F_SETLKW64:
504 case F_OFD_SETLK:
505 case F_OFD_SETLKW:
506 err = -EFAULT;
507 if (copy_from_user(&flock, argp, sizeof(flock)))
508 break;
509 err = fcntl_setlk64(fd, f.file, cmd, &flock);
510 break;
511 default:
512 err = do_fcntl(fd, cmd, arg, f.file);
513 break;
514 }
515out1:
516 fdput(f);
517out:
518 return err;
519}
520#endif
521
522#ifdef CONFIG_COMPAT
523/* careful - don't use anywhere else */
524#define copy_flock_fields(dst, src) \
525 (dst)->l_type = (src)->l_type; \
526 (dst)->l_whence = (src)->l_whence; \
527 (dst)->l_start = (src)->l_start; \
528 (dst)->l_len = (src)->l_len; \
529 (dst)->l_pid = (src)->l_pid;
530
531static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl)
532{
533 struct compat_flock fl;
534
535 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock)))
536 return -EFAULT;
537 copy_flock_fields(kfl, &fl);
538 return 0;
539}
540
541static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl)
542{
543 struct compat_flock64 fl;
544
545 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64)))
546 return -EFAULT;
547 copy_flock_fields(kfl, &fl);
548 return 0;
549}
550
551static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl)
552{
553 struct compat_flock fl;
554
555 memset(&fl, 0, sizeof(struct compat_flock));
556 copy_flock_fields(&fl, kfl);
557 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock)))
558 return -EFAULT;
559 return 0;
560}
561
562static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl)
563{
564 struct compat_flock64 fl;
565
566 BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start));
567 BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len));
568
569 memset(&fl, 0, sizeof(struct compat_flock64));
570 copy_flock_fields(&fl, kfl);
571 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
572 return -EFAULT;
573 return 0;
574}
575#undef copy_flock_fields
576
577static unsigned int
578convert_fcntl_cmd(unsigned int cmd)
579{
580 switch (cmd) {
581 case F_GETLK64:
582 return F_GETLK;
583 case F_SETLK64:
584 return F_SETLK;
585 case F_SETLKW64:
586 return F_SETLKW;
587 }
588
589 return cmd;
590}
591
592/*
593 * GETLK was successful and we need to return the data, but it needs to fit in
594 * the compat structure.
595 * l_start shouldn't be too big, unless the original start + end is greater than
596 * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
597 * -EOVERFLOW in that case. l_len could be too big, in which case we just
598 * truncate it, and only allow the app to see that part of the conflicting lock
599 * that might make sense to it anyway
600 */
601static int fixup_compat_flock(struct flock *flock)
602{
603 if (flock->l_start > COMPAT_OFF_T_MAX)
604 return -EOVERFLOW;
605 if (flock->l_len > COMPAT_OFF_T_MAX)
606 flock->l_len = COMPAT_OFF_T_MAX;
607 return 0;
608}
609
610static long do_compat_fcntl64(unsigned int fd, unsigned int cmd,
611 compat_ulong_t arg)
612{
613 struct fd f = fdget_raw(fd);
614 struct flock flock;
615 long err = -EBADF;
616
617 if (!f.file)
618 return err;
619
620 if (unlikely(f.file->f_mode & FMODE_PATH)) {
621 if (!check_fcntl_cmd(cmd))
622 goto out_put;
623 }
624
625 err = security_file_fcntl(f.file, cmd, arg);
626 if (err)
627 goto out_put;
628
629 switch (cmd) {
630 case F_GETLK:
631 err = get_compat_flock(&flock, compat_ptr(arg));
632 if (err)
633 break;
634 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
635 if (err)
636 break;
637 err = fixup_compat_flock(&flock);
638 if (!err)
639 err = put_compat_flock(&flock, compat_ptr(arg));
640 break;
641 case F_GETLK64:
642 case F_OFD_GETLK:
643 err = get_compat_flock64(&flock, compat_ptr(arg));
644 if (err)
645 break;
646 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
647 if (!err)
648 err = put_compat_flock64(&flock, compat_ptr(arg));
649 break;
650 case F_SETLK:
651 case F_SETLKW:
652 err = get_compat_flock(&flock, compat_ptr(arg));
653 if (err)
654 break;
655 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
656 break;
657 case F_SETLK64:
658 case F_SETLKW64:
659 case F_OFD_SETLK:
660 case F_OFD_SETLKW:
661 err = get_compat_flock64(&flock, compat_ptr(arg));
662 if (err)
663 break;
664 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
665 break;
666 default:
667 err = do_fcntl(fd, cmd, arg, f.file);
668 break;
669 }
670out_put:
671 fdput(f);
672 return err;
673}
674
675COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
676 compat_ulong_t, arg)
677{
678 return do_compat_fcntl64(fd, cmd, arg);
679}
680
681COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
682 compat_ulong_t, arg)
683{
684 switch (cmd) {
685 case F_GETLK64:
686 case F_SETLK64:
687 case F_SETLKW64:
688 case F_OFD_GETLK:
689 case F_OFD_SETLK:
690 case F_OFD_SETLKW:
691 return -EINVAL;
692 }
693 return do_compat_fcntl64(fd, cmd, arg);
694}
695#endif
696
697/* Table to convert sigio signal codes into poll band bitmaps */
698
699static const __poll_t band_table[NSIGPOLL] = {
700 EPOLLIN | EPOLLRDNORM, /* POLL_IN */
701 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */
702 EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */
703 EPOLLERR, /* POLL_ERR */
704 EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */
705 EPOLLHUP | EPOLLERR /* POLL_HUP */
706};
707
708static inline int sigio_perm(struct task_struct *p,
709 struct fown_struct *fown, int sig)
710{
711 const struct cred *cred;
712 int ret;
713
714 rcu_read_lock();
715 cred = __task_cred(p);
716 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
717 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
718 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
719 !security_file_send_sigiotask(p, fown, sig));
720 rcu_read_unlock();
721 return ret;
722}
723
724static void send_sigio_to_task(struct task_struct *p,
725 struct fown_struct *fown,
726 int fd, int reason, enum pid_type type)
727{
728 /*
729 * F_SETSIG can change ->signum lockless in parallel, make
730 * sure we read it once and use the same value throughout.
731 */
732 int signum = READ_ONCE(fown->signum);
733
734 if (!sigio_perm(p, fown, signum))
735 return;
736
737 switch (signum) {
738 default: {
739 kernel_siginfo_t si;
740
741 /* Queue a rt signal with the appropriate fd as its
742 value. We use SI_SIGIO as the source, not
743 SI_KERNEL, since kernel signals always get
744 delivered even if we can't queue. Failure to
745 queue in this case _should_ be reported; we fall
746 back to SIGIO in that case. --sct */
747 clear_siginfo(&si);
748 si.si_signo = signum;
749 si.si_errno = 0;
750 si.si_code = reason;
751 /*
752 * Posix definies POLL_IN and friends to be signal
753 * specific si_codes for SIG_POLL. Linux extended
754 * these si_codes to other signals in a way that is
755 * ambiguous if other signals also have signal
756 * specific si_codes. In that case use SI_SIGIO instead
757 * to remove the ambiguity.
758 */
759 if ((signum != SIGPOLL) && sig_specific_sicodes(signum))
760 si.si_code = SI_SIGIO;
761
762 /* Make sure we are called with one of the POLL_*
763 reasons, otherwise we could leak kernel stack into
764 userspace. */
765 BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL));
766 if (reason - POLL_IN >= NSIGPOLL)
767 si.si_band = ~0L;
768 else
769 si.si_band = mangle_poll(band_table[reason - POLL_IN]);
770 si.si_fd = fd;
771 if (!do_send_sig_info(signum, &si, p, type))
772 break;
773 }
774 fallthrough; /* fall back on the old plain SIGIO signal */
775 case 0:
776 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type);
777 }
778}
779
780void send_sigio(struct fown_struct *fown, int fd, int band)
781{
782 struct task_struct *p;
783 enum pid_type type;
784 struct pid *pid;
785
786 read_lock(&fown->lock);
787
788 type = fown->pid_type;
789 pid = fown->pid;
790 if (!pid)
791 goto out_unlock_fown;
792
793 if (type <= PIDTYPE_TGID) {
794 rcu_read_lock();
795 p = pid_task(pid, PIDTYPE_PID);
796 if (p)
797 send_sigio_to_task(p, fown, fd, band, type);
798 rcu_read_unlock();
799 } else {
800 read_lock(&tasklist_lock);
801 do_each_pid_task(pid, type, p) {
802 send_sigio_to_task(p, fown, fd, band, type);
803 } while_each_pid_task(pid, type, p);
804 read_unlock(&tasklist_lock);
805 }
806 out_unlock_fown:
807 read_unlock(&fown->lock);
808}
809
810static void send_sigurg_to_task(struct task_struct *p,
811 struct fown_struct *fown, enum pid_type type)
812{
813 if (sigio_perm(p, fown, SIGURG))
814 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type);
815}
816
817int send_sigurg(struct fown_struct *fown)
818{
819 struct task_struct *p;
820 enum pid_type type;
821 struct pid *pid;
822 int ret = 0;
823
824 read_lock(&fown->lock);
825
826 type = fown->pid_type;
827 pid = fown->pid;
828 if (!pid)
829 goto out_unlock_fown;
830
831 ret = 1;
832
833 if (type <= PIDTYPE_TGID) {
834 rcu_read_lock();
835 p = pid_task(pid, PIDTYPE_PID);
836 if (p)
837 send_sigurg_to_task(p, fown, type);
838 rcu_read_unlock();
839 } else {
840 read_lock(&tasklist_lock);
841 do_each_pid_task(pid, type, p) {
842 send_sigurg_to_task(p, fown, type);
843 } while_each_pid_task(pid, type, p);
844 read_unlock(&tasklist_lock);
845 }
846 out_unlock_fown:
847 read_unlock(&fown->lock);
848 return ret;
849}
850
851static DEFINE_SPINLOCK(fasync_lock);
852static struct kmem_cache *fasync_cache __read_mostly;
853
854static void fasync_free_rcu(struct rcu_head *head)
855{
856 kmem_cache_free(fasync_cache,
857 container_of(head, struct fasync_struct, fa_rcu));
858}
859
860/*
861 * Remove a fasync entry. If successfully removed, return
862 * positive and clear the FASYNC flag. If no entry exists,
863 * do nothing and return 0.
864 *
865 * NOTE! It is very important that the FASYNC flag always
866 * match the state "is the filp on a fasync list".
867 *
868 */
869int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
870{
871 struct fasync_struct *fa, **fp;
872 int result = 0;
873
874 spin_lock(&filp->f_lock);
875 spin_lock(&fasync_lock);
876 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
877 if (fa->fa_file != filp)
878 continue;
879
880 write_lock_irq(&fa->fa_lock);
881 fa->fa_file = NULL;
882 write_unlock_irq(&fa->fa_lock);
883
884 *fp = fa->fa_next;
885 call_rcu(&fa->fa_rcu, fasync_free_rcu);
886 filp->f_flags &= ~FASYNC;
887 result = 1;
888 break;
889 }
890 spin_unlock(&fasync_lock);
891 spin_unlock(&filp->f_lock);
892 return result;
893}
894
895struct fasync_struct *fasync_alloc(void)
896{
897 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
898}
899
900/*
901 * NOTE! This can be used only for unused fasync entries:
902 * entries that actually got inserted on the fasync list
903 * need to be released by rcu - see fasync_remove_entry.
904 */
905void fasync_free(struct fasync_struct *new)
906{
907 kmem_cache_free(fasync_cache, new);
908}
909
910/*
911 * Insert a new entry into the fasync list. Return the pointer to the
912 * old one if we didn't use the new one.
913 *
914 * NOTE! It is very important that the FASYNC flag always
915 * match the state "is the filp on a fasync list".
916 */
917struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
918{
919 struct fasync_struct *fa, **fp;
920
921 spin_lock(&filp->f_lock);
922 spin_lock(&fasync_lock);
923 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
924 if (fa->fa_file != filp)
925 continue;
926
927 write_lock_irq(&fa->fa_lock);
928 fa->fa_fd = fd;
929 write_unlock_irq(&fa->fa_lock);
930 goto out;
931 }
932
933 rwlock_init(&new->fa_lock);
934 new->magic = FASYNC_MAGIC;
935 new->fa_file = filp;
936 new->fa_fd = fd;
937 new->fa_next = *fapp;
938 rcu_assign_pointer(*fapp, new);
939 filp->f_flags |= FASYNC;
940
941out:
942 spin_unlock(&fasync_lock);
943 spin_unlock(&filp->f_lock);
944 return fa;
945}
946
947/*
948 * Add a fasync entry. Return negative on error, positive if
949 * added, and zero if did nothing but change an existing one.
950 */
951static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
952{
953 struct fasync_struct *new;
954
955 new = fasync_alloc();
956 if (!new)
957 return -ENOMEM;
958
959 /*
960 * fasync_insert_entry() returns the old (update) entry if
961 * it existed.
962 *
963 * So free the (unused) new entry and return 0 to let the
964 * caller know that we didn't add any new fasync entries.
965 */
966 if (fasync_insert_entry(fd, filp, fapp, new)) {
967 fasync_free(new);
968 return 0;
969 }
970
971 return 1;
972}
973
974/*
975 * fasync_helper() is used by almost all character device drivers
976 * to set up the fasync queue, and for regular files by the file
977 * lease code. It returns negative on error, 0 if it did no changes
978 * and positive if it added/deleted the entry.
979 */
980int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
981{
982 if (!on)
983 return fasync_remove_entry(filp, fapp);
984 return fasync_add_entry(fd, filp, fapp);
985}
986
987EXPORT_SYMBOL(fasync_helper);
988
989/*
990 * rcu_read_lock() is held
991 */
992static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
993{
994 while (fa) {
995 struct fown_struct *fown;
996
997 if (fa->magic != FASYNC_MAGIC) {
998 printk(KERN_ERR "kill_fasync: bad magic number in "
999 "fasync_struct!\n");
1000 return;
1001 }
1002 read_lock(&fa->fa_lock);
1003 if (fa->fa_file) {
1004 fown = &fa->fa_file->f_owner;
1005 /* Don't send SIGURG to processes which have not set a
1006 queued signum: SIGURG has its own default signalling
1007 mechanism. */
1008 if (!(sig == SIGURG && fown->signum == 0))
1009 send_sigio(fown, fa->fa_fd, band);
1010 }
1011 read_unlock(&fa->fa_lock);
1012 fa = rcu_dereference(fa->fa_next);
1013 }
1014}
1015
1016void kill_fasync(struct fasync_struct **fp, int sig, int band)
1017{
1018 /* First a quick test without locking: usually
1019 * the list is empty.
1020 */
1021 if (*fp) {
1022 rcu_read_lock();
1023 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
1024 rcu_read_unlock();
1025 }
1026}
1027EXPORT_SYMBOL(kill_fasync);
1028
1029static int __init fcntl_init(void)
1030{
1031 /*
1032 * Please add new bits here to ensure allocation uniqueness.
1033 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
1034 * is defined as O_NONBLOCK on some platforms and not on others.
1035 */
1036 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ !=
1037 HWEIGHT32(
1038 (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) |
1039 __FMODE_EXEC | __FMODE_NONOTIFY));
1040
1041 fasync_cache = kmem_cache_create("fasync_cache",
1042 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
1043 return 0;
1044}
1045
1046module_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/file.h>
14#include <linux/fdtable.h>
15#include <linux/capability.h>
16#include <linux/dnotify.h>
17#include <linux/slab.h>
18#include <linux/module.h>
19#include <linux/pipe_fs_i.h>
20#include <linux/security.h>
21#include <linux/ptrace.h>
22#include <linux/signal.h>
23#include <linux/rcupdate.h>
24#include <linux/pid_namespace.h>
25#include <linux/user_namespace.h>
26#include <linux/memfd.h>
27#include <linux/compat.h>
28#include <linux/mount.h>
29
30#include <linux/poll.h>
31#include <asm/siginfo.h>
32#include <linux/uaccess.h>
33
34#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
35
36static int setfl(int fd, struct file * filp, unsigned long arg)
37{
38 struct inode * inode = file_inode(filp);
39 int error = 0;
40
41 /*
42 * O_APPEND cannot be cleared if the file is marked as append-only
43 * and the file is open for write.
44 */
45 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
46 return -EPERM;
47
48 /* O_NOATIME can only be set by the owner or superuser */
49 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
50 if (!inode_owner_or_capable(file_mnt_user_ns(filp), inode))
51 return -EPERM;
52
53 /* required for strict SunOS emulation */
54 if (O_NONBLOCK != O_NDELAY)
55 if (arg & O_NDELAY)
56 arg |= O_NONBLOCK;
57
58 /* Pipe packetized mode is controlled by O_DIRECT flag */
59 if (!S_ISFIFO(inode->i_mode) && (arg & O_DIRECT)) {
60 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
61 !filp->f_mapping->a_ops->direct_IO)
62 return -EINVAL;
63 }
64
65 if (filp->f_op->check_flags)
66 error = filp->f_op->check_flags(arg);
67 if (error)
68 return error;
69
70 /*
71 * ->fasync() is responsible for setting the FASYNC bit.
72 */
73 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
74 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
75 if (error < 0)
76 goto out;
77 if (error > 0)
78 error = 0;
79 }
80 spin_lock(&filp->f_lock);
81 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
82 spin_unlock(&filp->f_lock);
83
84 out:
85 return error;
86}
87
88static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
89 int force)
90{
91 write_lock_irq(&filp->f_owner.lock);
92 if (force || !filp->f_owner.pid) {
93 put_pid(filp->f_owner.pid);
94 filp->f_owner.pid = get_pid(pid);
95 filp->f_owner.pid_type = type;
96
97 if (pid) {
98 const struct cred *cred = current_cred();
99 filp->f_owner.uid = cred->uid;
100 filp->f_owner.euid = cred->euid;
101 }
102 }
103 write_unlock_irq(&filp->f_owner.lock);
104}
105
106void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
107 int force)
108{
109 security_file_set_fowner(filp);
110 f_modown(filp, pid, type, force);
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 = NULL;
118 int who = arg, ret = 0;
119
120 type = PIDTYPE_TGID;
121 if (who < 0) {
122 /* avoid overflow below */
123 if (who == INT_MIN)
124 return -EINVAL;
125
126 type = PIDTYPE_PGID;
127 who = -who;
128 }
129
130 rcu_read_lock();
131 if (who) {
132 pid = find_vpid(who);
133 if (!pid)
134 ret = -ESRCH;
135 }
136
137 if (!ret)
138 __f_setown(filp, pid, type, force);
139 rcu_read_unlock();
140
141 return ret;
142}
143EXPORT_SYMBOL(f_setown);
144
145void f_delown(struct file *filp)
146{
147 f_modown(filp, NULL, PIDTYPE_TGID, 1);
148}
149
150pid_t f_getown(struct file *filp)
151{
152 pid_t pid = 0;
153
154 read_lock_irq(&filp->f_owner.lock);
155 rcu_read_lock();
156 if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type)) {
157 pid = pid_vnr(filp->f_owner.pid);
158 if (filp->f_owner.pid_type == PIDTYPE_PGID)
159 pid = -pid;
160 }
161 rcu_read_unlock();
162 read_unlock_irq(&filp->f_owner.lock);
163 return pid;
164}
165
166static int f_setown_ex(struct file *filp, unsigned long arg)
167{
168 struct f_owner_ex __user *owner_p = (void __user *)arg;
169 struct f_owner_ex owner;
170 struct pid *pid;
171 int type;
172 int ret;
173
174 ret = copy_from_user(&owner, owner_p, sizeof(owner));
175 if (ret)
176 return -EFAULT;
177
178 switch (owner.type) {
179 case F_OWNER_TID:
180 type = PIDTYPE_PID;
181 break;
182
183 case F_OWNER_PID:
184 type = PIDTYPE_TGID;
185 break;
186
187 case F_OWNER_PGRP:
188 type = PIDTYPE_PGID;
189 break;
190
191 default:
192 return -EINVAL;
193 }
194
195 rcu_read_lock();
196 pid = find_vpid(owner.pid);
197 if (owner.pid && !pid)
198 ret = -ESRCH;
199 else
200 __f_setown(filp, pid, type, 1);
201 rcu_read_unlock();
202
203 return ret;
204}
205
206static int f_getown_ex(struct file *filp, unsigned long arg)
207{
208 struct f_owner_ex __user *owner_p = (void __user *)arg;
209 struct f_owner_ex owner = {};
210 int ret = 0;
211
212 read_lock_irq(&filp->f_owner.lock);
213 rcu_read_lock();
214 if (pid_task(filp->f_owner.pid, filp->f_owner.pid_type))
215 owner.pid = pid_vnr(filp->f_owner.pid);
216 rcu_read_unlock();
217 switch (filp->f_owner.pid_type) {
218 case PIDTYPE_PID:
219 owner.type = F_OWNER_TID;
220 break;
221
222 case PIDTYPE_TGID:
223 owner.type = F_OWNER_PID;
224 break;
225
226 case PIDTYPE_PGID:
227 owner.type = F_OWNER_PGRP;
228 break;
229
230 default:
231 WARN_ON(1);
232 ret = -EINVAL;
233 break;
234 }
235 read_unlock_irq(&filp->f_owner.lock);
236
237 if (!ret) {
238 ret = copy_to_user(owner_p, &owner, sizeof(owner));
239 if (ret)
240 ret = -EFAULT;
241 }
242 return ret;
243}
244
245#ifdef CONFIG_CHECKPOINT_RESTORE
246static int f_getowner_uids(struct file *filp, unsigned long arg)
247{
248 struct user_namespace *user_ns = current_user_ns();
249 uid_t __user *dst = (void __user *)arg;
250 uid_t src[2];
251 int err;
252
253 read_lock_irq(&filp->f_owner.lock);
254 src[0] = from_kuid(user_ns, filp->f_owner.uid);
255 src[1] = from_kuid(user_ns, filp->f_owner.euid);
256 read_unlock_irq(&filp->f_owner.lock);
257
258 err = put_user(src[0], &dst[0]);
259 err |= put_user(src[1], &dst[1]);
260
261 return err;
262}
263#else
264static int f_getowner_uids(struct file *filp, unsigned long arg)
265{
266 return -EINVAL;
267}
268#endif
269
270static bool rw_hint_valid(enum rw_hint hint)
271{
272 switch (hint) {
273 case RWH_WRITE_LIFE_NOT_SET:
274 case RWH_WRITE_LIFE_NONE:
275 case RWH_WRITE_LIFE_SHORT:
276 case RWH_WRITE_LIFE_MEDIUM:
277 case RWH_WRITE_LIFE_LONG:
278 case RWH_WRITE_LIFE_EXTREME:
279 return true;
280 default:
281 return false;
282 }
283}
284
285static long fcntl_rw_hint(struct file *file, unsigned int cmd,
286 unsigned long arg)
287{
288 struct inode *inode = file_inode(file);
289 u64 __user *argp = (u64 __user *)arg;
290 enum rw_hint hint;
291 u64 h;
292
293 switch (cmd) {
294 case F_GET_FILE_RW_HINT:
295 h = file_write_hint(file);
296 if (copy_to_user(argp, &h, sizeof(*argp)))
297 return -EFAULT;
298 return 0;
299 case F_SET_FILE_RW_HINT:
300 if (copy_from_user(&h, argp, sizeof(h)))
301 return -EFAULT;
302 hint = (enum rw_hint) h;
303 if (!rw_hint_valid(hint))
304 return -EINVAL;
305
306 spin_lock(&file->f_lock);
307 file->f_write_hint = hint;
308 spin_unlock(&file->f_lock);
309 return 0;
310 case F_GET_RW_HINT:
311 h = inode->i_write_hint;
312 if (copy_to_user(argp, &h, sizeof(*argp)))
313 return -EFAULT;
314 return 0;
315 case F_SET_RW_HINT:
316 if (copy_from_user(&h, argp, sizeof(h)))
317 return -EFAULT;
318 hint = (enum rw_hint) h;
319 if (!rw_hint_valid(hint))
320 return -EINVAL;
321
322 inode_lock(inode);
323 inode->i_write_hint = hint;
324 inode_unlock(inode);
325 return 0;
326 default:
327 return -EINVAL;
328 }
329}
330
331static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
332 struct file *filp)
333{
334 void __user *argp = (void __user *)arg;
335 struct flock flock;
336 long err = -EINVAL;
337
338 switch (cmd) {
339 case F_DUPFD:
340 err = f_dupfd(arg, filp, 0);
341 break;
342 case F_DUPFD_CLOEXEC:
343 err = f_dupfd(arg, 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, arg & FD_CLOEXEC);
351 break;
352 case F_GETFL:
353 err = filp->f_flags;
354 break;
355 case F_SETFL:
356 err = setfl(fd, filp, arg);
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, arg, 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(arg)) {
410 break;
411 }
412 err = 0;
413 filp->f_owner.signum = arg;
414 break;
415 case F_GETLEASE:
416 err = fcntl_getlease(filp);
417 break;
418 case F_SETLEASE:
419 err = fcntl_setlease(fd, filp, arg);
420 break;
421 case F_NOTIFY:
422 err = fcntl_dirnotify(fd, filp, arg);
423 break;
424 case F_SETPIPE_SZ:
425 case F_GETPIPE_SZ:
426 err = pipe_fcntl(filp, cmd, arg);
427 break;
428 case F_ADD_SEALS:
429 case F_GET_SEALS:
430 err = memfd_fcntl(filp, cmd, arg);
431 break;
432 case F_GET_RW_HINT:
433 case F_SET_RW_HINT:
434 case F_GET_FILE_RW_HINT:
435 case F_SET_FILE_RW_HINT:
436 err = fcntl_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 __read_mostly;
864
865static void fasync_free_rcu(struct rcu_head *head)
866{
867 kmem_cache_free(fasync_cache,
868 container_of(head, struct fasync_struct, fa_rcu));
869}
870
871/*
872 * Remove a fasync entry. If successfully removed, return
873 * positive and clear the FASYNC flag. If no entry exists,
874 * do nothing and return 0.
875 *
876 * NOTE! It is very important that the FASYNC flag always
877 * match the state "is the filp on a fasync list".
878 *
879 */
880int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
881{
882 struct fasync_struct *fa, **fp;
883 int result = 0;
884
885 spin_lock(&filp->f_lock);
886 spin_lock(&fasync_lock);
887 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
888 if (fa->fa_file != filp)
889 continue;
890
891 write_lock_irq(&fa->fa_lock);
892 fa->fa_file = NULL;
893 write_unlock_irq(&fa->fa_lock);
894
895 *fp = fa->fa_next;
896 call_rcu(&fa->fa_rcu, fasync_free_rcu);
897 filp->f_flags &= ~FASYNC;
898 result = 1;
899 break;
900 }
901 spin_unlock(&fasync_lock);
902 spin_unlock(&filp->f_lock);
903 return result;
904}
905
906struct fasync_struct *fasync_alloc(void)
907{
908 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
909}
910
911/*
912 * NOTE! This can be used only for unused fasync entries:
913 * entries that actually got inserted on the fasync list
914 * need to be released by rcu - see fasync_remove_entry.
915 */
916void fasync_free(struct fasync_struct *new)
917{
918 kmem_cache_free(fasync_cache, new);
919}
920
921/*
922 * Insert a new entry into the fasync list. Return the pointer to the
923 * old one if we didn't use the new one.
924 *
925 * NOTE! It is very important that the FASYNC flag always
926 * match the state "is the filp on a fasync list".
927 */
928struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
929{
930 struct fasync_struct *fa, **fp;
931
932 spin_lock(&filp->f_lock);
933 spin_lock(&fasync_lock);
934 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
935 if (fa->fa_file != filp)
936 continue;
937
938 write_lock_irq(&fa->fa_lock);
939 fa->fa_fd = fd;
940 write_unlock_irq(&fa->fa_lock);
941 goto out;
942 }
943
944 rwlock_init(&new->fa_lock);
945 new->magic = FASYNC_MAGIC;
946 new->fa_file = filp;
947 new->fa_fd = fd;
948 new->fa_next = *fapp;
949 rcu_assign_pointer(*fapp, new);
950 filp->f_flags |= FASYNC;
951
952out:
953 spin_unlock(&fasync_lock);
954 spin_unlock(&filp->f_lock);
955 return fa;
956}
957
958/*
959 * Add a fasync entry. Return negative on error, positive if
960 * added, and zero if did nothing but change an existing one.
961 */
962static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
963{
964 struct fasync_struct *new;
965
966 new = fasync_alloc();
967 if (!new)
968 return -ENOMEM;
969
970 /*
971 * fasync_insert_entry() returns the old (update) entry if
972 * it existed.
973 *
974 * So free the (unused) new entry and return 0 to let the
975 * caller know that we didn't add any new fasync entries.
976 */
977 if (fasync_insert_entry(fd, filp, fapp, new)) {
978 fasync_free(new);
979 return 0;
980 }
981
982 return 1;
983}
984
985/*
986 * fasync_helper() is used by almost all character device drivers
987 * to set up the fasync queue, and for regular files by the file
988 * lease code. It returns negative on error, 0 if it did no changes
989 * and positive if it added/deleted the entry.
990 */
991int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
992{
993 if (!on)
994 return fasync_remove_entry(filp, fapp);
995 return fasync_add_entry(fd, filp, fapp);
996}
997
998EXPORT_SYMBOL(fasync_helper);
999
1000/*
1001 * rcu_read_lock() is held
1002 */
1003static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
1004{
1005 while (fa) {
1006 struct fown_struct *fown;
1007 unsigned long flags;
1008
1009 if (fa->magic != FASYNC_MAGIC) {
1010 printk(KERN_ERR "kill_fasync: bad magic number in "
1011 "fasync_struct!\n");
1012 return;
1013 }
1014 read_lock_irqsave(&fa->fa_lock, flags);
1015 if (fa->fa_file) {
1016 fown = &fa->fa_file->f_owner;
1017 /* Don't send SIGURG to processes which have not set a
1018 queued signum: SIGURG has its own default signalling
1019 mechanism. */
1020 if (!(sig == SIGURG && fown->signum == 0))
1021 send_sigio(fown, fa->fa_fd, band);
1022 }
1023 read_unlock_irqrestore(&fa->fa_lock, flags);
1024 fa = rcu_dereference(fa->fa_next);
1025 }
1026}
1027
1028void kill_fasync(struct fasync_struct **fp, int sig, int band)
1029{
1030 /* First a quick test without locking: usually
1031 * the list is empty.
1032 */
1033 if (*fp) {
1034 rcu_read_lock();
1035 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
1036 rcu_read_unlock();
1037 }
1038}
1039EXPORT_SYMBOL(kill_fasync);
1040
1041static int __init fcntl_init(void)
1042{
1043 /*
1044 * Please add new bits here to ensure allocation uniqueness.
1045 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
1046 * is defined as O_NONBLOCK on some platforms and not on others.
1047 */
1048 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ !=
1049 HWEIGHT32(
1050 (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) |
1051 __FMODE_EXEC | __FMODE_NONOTIFY));
1052
1053 fasync_cache = kmem_cache_create("fasync_cache",
1054 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
1055 return 0;
1056}
1057
1058module_init(fcntl_init)