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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#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) &&
60 (arg & O_DIRECT) &&
61 !(filp->f_mode & FMODE_CAN_ODIRECT))
62 return -EINVAL;
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 filp->f_iocb_flags = iocb_flags(filp);
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_RW_HINT:
295 h = inode->i_write_hint;
296 if (copy_to_user(argp, &h, sizeof(*argp)))
297 return -EFAULT;
298 return 0;
299 case F_SET_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 inode_lock(inode);
307 inode->i_write_hint = hint;
308 inode_unlock(inode);
309 return 0;
310 default:
311 return -EINVAL;
312 }
313}
314
315static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
316 struct file *filp)
317{
318 void __user *argp = (void __user *)arg;
319 struct flock flock;
320 long err = -EINVAL;
321
322 switch (cmd) {
323 case F_DUPFD:
324 err = f_dupfd(arg, filp, 0);
325 break;
326 case F_DUPFD_CLOEXEC:
327 err = f_dupfd(arg, filp, O_CLOEXEC);
328 break;
329 case F_GETFD:
330 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
331 break;
332 case F_SETFD:
333 err = 0;
334 set_close_on_exec(fd, arg & FD_CLOEXEC);
335 break;
336 case F_GETFL:
337 err = filp->f_flags;
338 break;
339 case F_SETFL:
340 err = setfl(fd, filp, arg);
341 break;
342#if BITS_PER_LONG != 32
343 /* 32-bit arches must use fcntl64() */
344 case F_OFD_GETLK:
345#endif
346 case F_GETLK:
347 if (copy_from_user(&flock, argp, sizeof(flock)))
348 return -EFAULT;
349 err = fcntl_getlk(filp, cmd, &flock);
350 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
351 return -EFAULT;
352 break;
353#if BITS_PER_LONG != 32
354 /* 32-bit arches must use fcntl64() */
355 case F_OFD_SETLK:
356 case F_OFD_SETLKW:
357 fallthrough;
358#endif
359 case F_SETLK:
360 case F_SETLKW:
361 if (copy_from_user(&flock, argp, sizeof(flock)))
362 return -EFAULT;
363 err = fcntl_setlk(fd, filp, cmd, &flock);
364 break;
365 case F_GETOWN:
366 /*
367 * XXX If f_owner is a process group, the
368 * negative return value will get converted
369 * into an error. Oops. If we keep the
370 * current syscall conventions, the only way
371 * to fix this will be in libc.
372 */
373 err = f_getown(filp);
374 force_successful_syscall_return();
375 break;
376 case F_SETOWN:
377 err = f_setown(filp, arg, 1);
378 break;
379 case F_GETOWN_EX:
380 err = f_getown_ex(filp, arg);
381 break;
382 case F_SETOWN_EX:
383 err = f_setown_ex(filp, arg);
384 break;
385 case F_GETOWNER_UIDS:
386 err = f_getowner_uids(filp, arg);
387 break;
388 case F_GETSIG:
389 err = filp->f_owner.signum;
390 break;
391 case F_SETSIG:
392 /* arg == 0 restores default behaviour. */
393 if (!valid_signal(arg)) {
394 break;
395 }
396 err = 0;
397 filp->f_owner.signum = arg;
398 break;
399 case F_GETLEASE:
400 err = fcntl_getlease(filp);
401 break;
402 case F_SETLEASE:
403 err = fcntl_setlease(fd, filp, arg);
404 break;
405 case F_NOTIFY:
406 err = fcntl_dirnotify(fd, filp, arg);
407 break;
408 case F_SETPIPE_SZ:
409 case F_GETPIPE_SZ:
410 err = pipe_fcntl(filp, cmd, arg);
411 break;
412 case F_ADD_SEALS:
413 case F_GET_SEALS:
414 err = memfd_fcntl(filp, cmd, arg);
415 break;
416 case F_GET_RW_HINT:
417 case F_SET_RW_HINT:
418 err = fcntl_rw_hint(filp, cmd, arg);
419 break;
420 default:
421 break;
422 }
423 return err;
424}
425
426static int check_fcntl_cmd(unsigned cmd)
427{
428 switch (cmd) {
429 case F_DUPFD:
430 case F_DUPFD_CLOEXEC:
431 case F_GETFD:
432 case F_SETFD:
433 case F_GETFL:
434 return 1;
435 }
436 return 0;
437}
438
439SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
440{
441 struct fd f = fdget_raw(fd);
442 long err = -EBADF;
443
444 if (!f.file)
445 goto out;
446
447 if (unlikely(f.file->f_mode & FMODE_PATH)) {
448 if (!check_fcntl_cmd(cmd))
449 goto out1;
450 }
451
452 err = security_file_fcntl(f.file, cmd, arg);
453 if (!err)
454 err = do_fcntl(fd, cmd, arg, f.file);
455
456out1:
457 fdput(f);
458out:
459 return err;
460}
461
462#if BITS_PER_LONG == 32
463SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
464 unsigned long, arg)
465{
466 void __user *argp = (void __user *)arg;
467 struct fd f = fdget_raw(fd);
468 struct flock64 flock;
469 long err = -EBADF;
470
471 if (!f.file)
472 goto out;
473
474 if (unlikely(f.file->f_mode & FMODE_PATH)) {
475 if (!check_fcntl_cmd(cmd))
476 goto out1;
477 }
478
479 err = security_file_fcntl(f.file, cmd, arg);
480 if (err)
481 goto out1;
482
483 switch (cmd) {
484 case F_GETLK64:
485 case F_OFD_GETLK:
486 err = -EFAULT;
487 if (copy_from_user(&flock, argp, sizeof(flock)))
488 break;
489 err = fcntl_getlk64(f.file, cmd, &flock);
490 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
491 err = -EFAULT;
492 break;
493 case F_SETLK64:
494 case F_SETLKW64:
495 case F_OFD_SETLK:
496 case F_OFD_SETLKW:
497 err = -EFAULT;
498 if (copy_from_user(&flock, argp, sizeof(flock)))
499 break;
500 err = fcntl_setlk64(fd, f.file, cmd, &flock);
501 break;
502 default:
503 err = do_fcntl(fd, cmd, arg, f.file);
504 break;
505 }
506out1:
507 fdput(f);
508out:
509 return err;
510}
511#endif
512
513#ifdef CONFIG_COMPAT
514/* careful - don't use anywhere else */
515#define copy_flock_fields(dst, src) \
516 (dst)->l_type = (src)->l_type; \
517 (dst)->l_whence = (src)->l_whence; \
518 (dst)->l_start = (src)->l_start; \
519 (dst)->l_len = (src)->l_len; \
520 (dst)->l_pid = (src)->l_pid;
521
522static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl)
523{
524 struct compat_flock fl;
525
526 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock)))
527 return -EFAULT;
528 copy_flock_fields(kfl, &fl);
529 return 0;
530}
531
532static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl)
533{
534 struct compat_flock64 fl;
535
536 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64)))
537 return -EFAULT;
538 copy_flock_fields(kfl, &fl);
539 return 0;
540}
541
542static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl)
543{
544 struct compat_flock fl;
545
546 memset(&fl, 0, sizeof(struct compat_flock));
547 copy_flock_fields(&fl, kfl);
548 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock)))
549 return -EFAULT;
550 return 0;
551}
552
553static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl)
554{
555 struct compat_flock64 fl;
556
557 BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start));
558 BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len));
559
560 memset(&fl, 0, sizeof(struct compat_flock64));
561 copy_flock_fields(&fl, kfl);
562 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
563 return -EFAULT;
564 return 0;
565}
566#undef copy_flock_fields
567
568static unsigned int
569convert_fcntl_cmd(unsigned int cmd)
570{
571 switch (cmd) {
572 case F_GETLK64:
573 return F_GETLK;
574 case F_SETLK64:
575 return F_SETLK;
576 case F_SETLKW64:
577 return F_SETLKW;
578 }
579
580 return cmd;
581}
582
583/*
584 * GETLK was successful and we need to return the data, but it needs to fit in
585 * the compat structure.
586 * l_start shouldn't be too big, unless the original start + end is greater than
587 * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
588 * -EOVERFLOW in that case. l_len could be too big, in which case we just
589 * truncate it, and only allow the app to see that part of the conflicting lock
590 * that might make sense to it anyway
591 */
592static int fixup_compat_flock(struct flock *flock)
593{
594 if (flock->l_start > COMPAT_OFF_T_MAX)
595 return -EOVERFLOW;
596 if (flock->l_len > COMPAT_OFF_T_MAX)
597 flock->l_len = COMPAT_OFF_T_MAX;
598 return 0;
599}
600
601static long do_compat_fcntl64(unsigned int fd, unsigned int cmd,
602 compat_ulong_t arg)
603{
604 struct fd f = fdget_raw(fd);
605 struct flock flock;
606 long err = -EBADF;
607
608 if (!f.file)
609 return err;
610
611 if (unlikely(f.file->f_mode & FMODE_PATH)) {
612 if (!check_fcntl_cmd(cmd))
613 goto out_put;
614 }
615
616 err = security_file_fcntl(f.file, cmd, arg);
617 if (err)
618 goto out_put;
619
620 switch (cmd) {
621 case F_GETLK:
622 err = get_compat_flock(&flock, compat_ptr(arg));
623 if (err)
624 break;
625 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
626 if (err)
627 break;
628 err = fixup_compat_flock(&flock);
629 if (!err)
630 err = put_compat_flock(&flock, compat_ptr(arg));
631 break;
632 case F_GETLK64:
633 case F_OFD_GETLK:
634 err = get_compat_flock64(&flock, compat_ptr(arg));
635 if (err)
636 break;
637 err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
638 if (!err)
639 err = put_compat_flock64(&flock, compat_ptr(arg));
640 break;
641 case F_SETLK:
642 case F_SETLKW:
643 err = get_compat_flock(&flock, compat_ptr(arg));
644 if (err)
645 break;
646 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
647 break;
648 case F_SETLK64:
649 case F_SETLKW64:
650 case F_OFD_SETLK:
651 case F_OFD_SETLKW:
652 err = get_compat_flock64(&flock, compat_ptr(arg));
653 if (err)
654 break;
655 err = fcntl_setlk(fd, f.file, convert_fcntl_cmd(cmd), &flock);
656 break;
657 default:
658 err = do_fcntl(fd, cmd, arg, f.file);
659 break;
660 }
661out_put:
662 fdput(f);
663 return err;
664}
665
666COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
667 compat_ulong_t, arg)
668{
669 return do_compat_fcntl64(fd, cmd, arg);
670}
671
672COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
673 compat_ulong_t, arg)
674{
675 switch (cmd) {
676 case F_GETLK64:
677 case F_SETLK64:
678 case F_SETLKW64:
679 case F_OFD_GETLK:
680 case F_OFD_SETLK:
681 case F_OFD_SETLKW:
682 return -EINVAL;
683 }
684 return do_compat_fcntl64(fd, cmd, arg);
685}
686#endif
687
688/* Table to convert sigio signal codes into poll band bitmaps */
689
690static const __poll_t band_table[NSIGPOLL] = {
691 EPOLLIN | EPOLLRDNORM, /* POLL_IN */
692 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */
693 EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */
694 EPOLLERR, /* POLL_ERR */
695 EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */
696 EPOLLHUP | EPOLLERR /* POLL_HUP */
697};
698
699static inline int sigio_perm(struct task_struct *p,
700 struct fown_struct *fown, int sig)
701{
702 const struct cred *cred;
703 int ret;
704
705 rcu_read_lock();
706 cred = __task_cred(p);
707 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
708 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
709 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
710 !security_file_send_sigiotask(p, fown, sig));
711 rcu_read_unlock();
712 return ret;
713}
714
715static void send_sigio_to_task(struct task_struct *p,
716 struct fown_struct *fown,
717 int fd, int reason, enum pid_type type)
718{
719 /*
720 * F_SETSIG can change ->signum lockless in parallel, make
721 * sure we read it once and use the same value throughout.
722 */
723 int signum = READ_ONCE(fown->signum);
724
725 if (!sigio_perm(p, fown, signum))
726 return;
727
728 switch (signum) {
729 default: {
730 kernel_siginfo_t si;
731
732 /* Queue a rt signal with the appropriate fd as its
733 value. We use SI_SIGIO as the source, not
734 SI_KERNEL, since kernel signals always get
735 delivered even if we can't queue. Failure to
736 queue in this case _should_ be reported; we fall
737 back to SIGIO in that case. --sct */
738 clear_siginfo(&si);
739 si.si_signo = signum;
740 si.si_errno = 0;
741 si.si_code = reason;
742 /*
743 * Posix definies POLL_IN and friends to be signal
744 * specific si_codes for SIG_POLL. Linux extended
745 * these si_codes to other signals in a way that is
746 * ambiguous if other signals also have signal
747 * specific si_codes. In that case use SI_SIGIO instead
748 * to remove the ambiguity.
749 */
750 if ((signum != SIGPOLL) && sig_specific_sicodes(signum))
751 si.si_code = SI_SIGIO;
752
753 /* Make sure we are called with one of the POLL_*
754 reasons, otherwise we could leak kernel stack into
755 userspace. */
756 BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL));
757 if (reason - POLL_IN >= NSIGPOLL)
758 si.si_band = ~0L;
759 else
760 si.si_band = mangle_poll(band_table[reason - POLL_IN]);
761 si.si_fd = fd;
762 if (!do_send_sig_info(signum, &si, p, type))
763 break;
764 }
765 fallthrough; /* fall back on the old plain SIGIO signal */
766 case 0:
767 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type);
768 }
769}
770
771void send_sigio(struct fown_struct *fown, int fd, int band)
772{
773 struct task_struct *p;
774 enum pid_type type;
775 unsigned long flags;
776 struct pid *pid;
777
778 read_lock_irqsave(&fown->lock, flags);
779
780 type = fown->pid_type;
781 pid = fown->pid;
782 if (!pid)
783 goto out_unlock_fown;
784
785 if (type <= PIDTYPE_TGID) {
786 rcu_read_lock();
787 p = pid_task(pid, PIDTYPE_PID);
788 if (p)
789 send_sigio_to_task(p, fown, fd, band, type);
790 rcu_read_unlock();
791 } else {
792 read_lock(&tasklist_lock);
793 do_each_pid_task(pid, type, p) {
794 send_sigio_to_task(p, fown, fd, band, type);
795 } while_each_pid_task(pid, type, p);
796 read_unlock(&tasklist_lock);
797 }
798 out_unlock_fown:
799 read_unlock_irqrestore(&fown->lock, flags);
800}
801
802static void send_sigurg_to_task(struct task_struct *p,
803 struct fown_struct *fown, enum pid_type type)
804{
805 if (sigio_perm(p, fown, SIGURG))
806 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type);
807}
808
809int send_sigurg(struct fown_struct *fown)
810{
811 struct task_struct *p;
812 enum pid_type type;
813 struct pid *pid;
814 unsigned long flags;
815 int ret = 0;
816
817 read_lock_irqsave(&fown->lock, flags);
818
819 type = fown->pid_type;
820 pid = fown->pid;
821 if (!pid)
822 goto out_unlock_fown;
823
824 ret = 1;
825
826 if (type <= PIDTYPE_TGID) {
827 rcu_read_lock();
828 p = pid_task(pid, PIDTYPE_PID);
829 if (p)
830 send_sigurg_to_task(p, fown, type);
831 rcu_read_unlock();
832 } else {
833 read_lock(&tasklist_lock);
834 do_each_pid_task(pid, type, p) {
835 send_sigurg_to_task(p, fown, type);
836 } while_each_pid_task(pid, type, p);
837 read_unlock(&tasklist_lock);
838 }
839 out_unlock_fown:
840 read_unlock_irqrestore(&fown->lock, flags);
841 return ret;
842}
843
844static DEFINE_SPINLOCK(fasync_lock);
845static struct kmem_cache *fasync_cache __read_mostly;
846
847static void fasync_free_rcu(struct rcu_head *head)
848{
849 kmem_cache_free(fasync_cache,
850 container_of(head, struct fasync_struct, fa_rcu));
851}
852
853/*
854 * Remove a fasync entry. If successfully removed, return
855 * positive and clear the FASYNC flag. If no entry exists,
856 * do nothing and return 0.
857 *
858 * NOTE! It is very important that the FASYNC flag always
859 * match the state "is the filp on a fasync list".
860 *
861 */
862int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
863{
864 struct fasync_struct *fa, **fp;
865 int result = 0;
866
867 spin_lock(&filp->f_lock);
868 spin_lock(&fasync_lock);
869 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
870 if (fa->fa_file != filp)
871 continue;
872
873 write_lock_irq(&fa->fa_lock);
874 fa->fa_file = NULL;
875 write_unlock_irq(&fa->fa_lock);
876
877 *fp = fa->fa_next;
878 call_rcu(&fa->fa_rcu, fasync_free_rcu);
879 filp->f_flags &= ~FASYNC;
880 result = 1;
881 break;
882 }
883 spin_unlock(&fasync_lock);
884 spin_unlock(&filp->f_lock);
885 return result;
886}
887
888struct fasync_struct *fasync_alloc(void)
889{
890 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
891}
892
893/*
894 * NOTE! This can be used only for unused fasync entries:
895 * entries that actually got inserted on the fasync list
896 * need to be released by rcu - see fasync_remove_entry.
897 */
898void fasync_free(struct fasync_struct *new)
899{
900 kmem_cache_free(fasync_cache, new);
901}
902
903/*
904 * Insert a new entry into the fasync list. Return the pointer to the
905 * old one if we didn't use the new one.
906 *
907 * NOTE! It is very important that the FASYNC flag always
908 * match the state "is the filp on a fasync list".
909 */
910struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
911{
912 struct fasync_struct *fa, **fp;
913
914 spin_lock(&filp->f_lock);
915 spin_lock(&fasync_lock);
916 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
917 if (fa->fa_file != filp)
918 continue;
919
920 write_lock_irq(&fa->fa_lock);
921 fa->fa_fd = fd;
922 write_unlock_irq(&fa->fa_lock);
923 goto out;
924 }
925
926 rwlock_init(&new->fa_lock);
927 new->magic = FASYNC_MAGIC;
928 new->fa_file = filp;
929 new->fa_fd = fd;
930 new->fa_next = *fapp;
931 rcu_assign_pointer(*fapp, new);
932 filp->f_flags |= FASYNC;
933
934out:
935 spin_unlock(&fasync_lock);
936 spin_unlock(&filp->f_lock);
937 return fa;
938}
939
940/*
941 * Add a fasync entry. Return negative on error, positive if
942 * added, and zero if did nothing but change an existing one.
943 */
944static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
945{
946 struct fasync_struct *new;
947
948 new = fasync_alloc();
949 if (!new)
950 return -ENOMEM;
951
952 /*
953 * fasync_insert_entry() returns the old (update) entry if
954 * it existed.
955 *
956 * So free the (unused) new entry and return 0 to let the
957 * caller know that we didn't add any new fasync entries.
958 */
959 if (fasync_insert_entry(fd, filp, fapp, new)) {
960 fasync_free(new);
961 return 0;
962 }
963
964 return 1;
965}
966
967/*
968 * fasync_helper() is used by almost all character device drivers
969 * to set up the fasync queue, and for regular files by the file
970 * lease code. It returns negative on error, 0 if it did no changes
971 * and positive if it added/deleted the entry.
972 */
973int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
974{
975 if (!on)
976 return fasync_remove_entry(filp, fapp);
977 return fasync_add_entry(fd, filp, fapp);
978}
979
980EXPORT_SYMBOL(fasync_helper);
981
982/*
983 * rcu_read_lock() is held
984 */
985static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
986{
987 while (fa) {
988 struct fown_struct *fown;
989 unsigned long flags;
990
991 if (fa->magic != FASYNC_MAGIC) {
992 printk(KERN_ERR "kill_fasync: bad magic number in "
993 "fasync_struct!\n");
994 return;
995 }
996 read_lock_irqsave(&fa->fa_lock, flags);
997 if (fa->fa_file) {
998 fown = &fa->fa_file->f_owner;
999 /* Don't send SIGURG to processes which have not set a
1000 queued signum: SIGURG has its own default signalling
1001 mechanism. */
1002 if (!(sig == SIGURG && fown->signum == 0))
1003 send_sigio(fown, fa->fa_fd, band);
1004 }
1005 read_unlock_irqrestore(&fa->fa_lock, flags);
1006 fa = rcu_dereference(fa->fa_next);
1007 }
1008}
1009
1010void kill_fasync(struct fasync_struct **fp, int sig, int band)
1011{
1012 /* First a quick test without locking: usually
1013 * the list is empty.
1014 */
1015 if (*fp) {
1016 rcu_read_lock();
1017 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
1018 rcu_read_unlock();
1019 }
1020}
1021EXPORT_SYMBOL(kill_fasync);
1022
1023static int __init fcntl_init(void)
1024{
1025 /*
1026 * Please add new bits here to ensure allocation uniqueness.
1027 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
1028 * is defined as O_NONBLOCK on some platforms and not on others.
1029 */
1030 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ !=
1031 HWEIGHT32(
1032 (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) |
1033 __FMODE_EXEC | __FMODE_NONOTIFY));
1034
1035 fasync_cache = kmem_cache_create("fasync_cache",
1036 sizeof(struct fasync_struct), 0,
1037 SLAB_PANIC | SLAB_ACCOUNT, NULL);
1038 return 0;
1039}
1040
1041module_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/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#include <linux/rw_hint.h>
30
31#include <linux/poll.h>
32#include <asm/siginfo.h>
33#include <linux/uaccess.h>
34
35#include "internal.h"
36
37#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
38
39static int setfl(int fd, struct file * filp, unsigned int arg)
40{
41 struct inode * inode = file_inode(filp);
42 int error = 0;
43
44 /*
45 * O_APPEND cannot be cleared if the file is marked as append-only
46 * and the file is open for write.
47 */
48 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
49 return -EPERM;
50
51 /* O_NOATIME can only be set by the owner or superuser */
52 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
53 if (!inode_owner_or_capable(file_mnt_idmap(filp), inode))
54 return -EPERM;
55
56 /* required for strict SunOS emulation */
57 if (O_NONBLOCK != O_NDELAY)
58 if (arg & O_NDELAY)
59 arg |= O_NONBLOCK;
60
61 /* Pipe packetized mode is controlled by O_DIRECT flag */
62 if (!S_ISFIFO(inode->i_mode) &&
63 (arg & O_DIRECT) &&
64 !(filp->f_mode & FMODE_CAN_ODIRECT))
65 return -EINVAL;
66
67 if (filp->f_op->check_flags)
68 error = filp->f_op->check_flags(arg);
69 if (error)
70 return error;
71
72 /*
73 * ->fasync() is responsible for setting the FASYNC bit.
74 */
75 if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) {
76 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
77 if (error < 0)
78 goto out;
79 if (error > 0)
80 error = 0;
81 }
82 spin_lock(&filp->f_lock);
83 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
84 filp->f_iocb_flags = iocb_flags(filp);
85 spin_unlock(&filp->f_lock);
86
87 out:
88 return error;
89}
90
91/*
92 * Allocate an file->f_owner struct if it doesn't exist, handling racing
93 * allocations correctly.
94 */
95int file_f_owner_allocate(struct file *file)
96{
97 struct fown_struct *f_owner;
98
99 f_owner = file_f_owner(file);
100 if (f_owner)
101 return 0;
102
103 f_owner = kzalloc(sizeof(struct fown_struct), GFP_KERNEL);
104 if (!f_owner)
105 return -ENOMEM;
106
107 rwlock_init(&f_owner->lock);
108 f_owner->file = file;
109 /* If someone else raced us, drop our allocation. */
110 if (unlikely(cmpxchg(&file->f_owner, NULL, f_owner)))
111 kfree(f_owner);
112 return 0;
113}
114EXPORT_SYMBOL(file_f_owner_allocate);
115
116void file_f_owner_release(struct file *file)
117{
118 struct fown_struct *f_owner;
119
120 f_owner = file_f_owner(file);
121 if (f_owner) {
122 put_pid(f_owner->pid);
123 kfree(f_owner);
124 }
125}
126
127void __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
128 int force)
129{
130 struct fown_struct *f_owner;
131
132 f_owner = file_f_owner(filp);
133 if (WARN_ON_ONCE(!f_owner))
134 return;
135
136 write_lock_irq(&f_owner->lock);
137 if (force || !f_owner->pid) {
138 put_pid(f_owner->pid);
139 f_owner->pid = get_pid(pid);
140 f_owner->pid_type = type;
141
142 if (pid) {
143 const struct cred *cred = current_cred();
144 security_file_set_fowner(filp);
145 f_owner->uid = cred->uid;
146 f_owner->euid = cred->euid;
147 }
148 }
149 write_unlock_irq(&f_owner->lock);
150}
151EXPORT_SYMBOL(__f_setown);
152
153int f_setown(struct file *filp, int who, int force)
154{
155 enum pid_type type;
156 struct pid *pid = NULL;
157 int ret = 0;
158
159 might_sleep();
160
161 type = PIDTYPE_TGID;
162 if (who < 0) {
163 /* avoid overflow below */
164 if (who == INT_MIN)
165 return -EINVAL;
166
167 type = PIDTYPE_PGID;
168 who = -who;
169 }
170
171 ret = file_f_owner_allocate(filp);
172 if (ret)
173 return ret;
174
175 rcu_read_lock();
176 if (who) {
177 pid = find_vpid(who);
178 if (!pid)
179 ret = -ESRCH;
180 }
181
182 if (!ret)
183 __f_setown(filp, pid, type, force);
184 rcu_read_unlock();
185
186 return ret;
187}
188EXPORT_SYMBOL(f_setown);
189
190void f_delown(struct file *filp)
191{
192 __f_setown(filp, NULL, PIDTYPE_TGID, 1);
193}
194
195pid_t f_getown(struct file *filp)
196{
197 pid_t pid = 0;
198 struct fown_struct *f_owner;
199
200 f_owner = file_f_owner(filp);
201 if (!f_owner)
202 return pid;
203
204 read_lock_irq(&f_owner->lock);
205 rcu_read_lock();
206 if (pid_task(f_owner->pid, f_owner->pid_type)) {
207 pid = pid_vnr(f_owner->pid);
208 if (f_owner->pid_type == PIDTYPE_PGID)
209 pid = -pid;
210 }
211 rcu_read_unlock();
212 read_unlock_irq(&f_owner->lock);
213 return pid;
214}
215
216static int f_setown_ex(struct file *filp, unsigned long arg)
217{
218 struct f_owner_ex __user *owner_p = (void __user *)arg;
219 struct f_owner_ex owner;
220 struct pid *pid;
221 int type;
222 int ret;
223
224 ret = copy_from_user(&owner, owner_p, sizeof(owner));
225 if (ret)
226 return -EFAULT;
227
228 switch (owner.type) {
229 case F_OWNER_TID:
230 type = PIDTYPE_PID;
231 break;
232
233 case F_OWNER_PID:
234 type = PIDTYPE_TGID;
235 break;
236
237 case F_OWNER_PGRP:
238 type = PIDTYPE_PGID;
239 break;
240
241 default:
242 return -EINVAL;
243 }
244
245 ret = file_f_owner_allocate(filp);
246 if (ret)
247 return ret;
248
249 rcu_read_lock();
250 pid = find_vpid(owner.pid);
251 if (owner.pid && !pid)
252 ret = -ESRCH;
253 else
254 __f_setown(filp, pid, type, 1);
255 rcu_read_unlock();
256
257 return ret;
258}
259
260static int f_getown_ex(struct file *filp, unsigned long arg)
261{
262 struct f_owner_ex __user *owner_p = (void __user *)arg;
263 struct f_owner_ex owner = {};
264 int ret = 0;
265 struct fown_struct *f_owner;
266 enum pid_type pid_type = PIDTYPE_PID;
267
268 f_owner = file_f_owner(filp);
269 if (f_owner) {
270 read_lock_irq(&f_owner->lock);
271 rcu_read_lock();
272 if (pid_task(f_owner->pid, f_owner->pid_type))
273 owner.pid = pid_vnr(f_owner->pid);
274 rcu_read_unlock();
275 pid_type = f_owner->pid_type;
276 }
277
278 switch (pid_type) {
279 case PIDTYPE_PID:
280 owner.type = F_OWNER_TID;
281 break;
282
283 case PIDTYPE_TGID:
284 owner.type = F_OWNER_PID;
285 break;
286
287 case PIDTYPE_PGID:
288 owner.type = F_OWNER_PGRP;
289 break;
290
291 default:
292 WARN_ON(1);
293 ret = -EINVAL;
294 break;
295 }
296 if (f_owner)
297 read_unlock_irq(&f_owner->lock);
298
299 if (!ret) {
300 ret = copy_to_user(owner_p, &owner, sizeof(owner));
301 if (ret)
302 ret = -EFAULT;
303 }
304 return ret;
305}
306
307#ifdef CONFIG_CHECKPOINT_RESTORE
308static int f_getowner_uids(struct file *filp, unsigned long arg)
309{
310 struct user_namespace *user_ns = current_user_ns();
311 struct fown_struct *f_owner;
312 uid_t __user *dst = (void __user *)arg;
313 uid_t src[2] = {0, 0};
314 int err;
315
316 f_owner = file_f_owner(filp);
317 if (f_owner) {
318 read_lock_irq(&f_owner->lock);
319 src[0] = from_kuid(user_ns, f_owner->uid);
320 src[1] = from_kuid(user_ns, f_owner->euid);
321 read_unlock_irq(&f_owner->lock);
322 }
323
324 err = put_user(src[0], &dst[0]);
325 err |= put_user(src[1], &dst[1]);
326
327 return err;
328}
329#else
330static int f_getowner_uids(struct file *filp, unsigned long arg)
331{
332 return -EINVAL;
333}
334#endif
335
336static bool rw_hint_valid(u64 hint)
337{
338 BUILD_BUG_ON(WRITE_LIFE_NOT_SET != RWH_WRITE_LIFE_NOT_SET);
339 BUILD_BUG_ON(WRITE_LIFE_NONE != RWH_WRITE_LIFE_NONE);
340 BUILD_BUG_ON(WRITE_LIFE_SHORT != RWH_WRITE_LIFE_SHORT);
341 BUILD_BUG_ON(WRITE_LIFE_MEDIUM != RWH_WRITE_LIFE_MEDIUM);
342 BUILD_BUG_ON(WRITE_LIFE_LONG != RWH_WRITE_LIFE_LONG);
343 BUILD_BUG_ON(WRITE_LIFE_EXTREME != RWH_WRITE_LIFE_EXTREME);
344
345 switch (hint) {
346 case RWH_WRITE_LIFE_NOT_SET:
347 case RWH_WRITE_LIFE_NONE:
348 case RWH_WRITE_LIFE_SHORT:
349 case RWH_WRITE_LIFE_MEDIUM:
350 case RWH_WRITE_LIFE_LONG:
351 case RWH_WRITE_LIFE_EXTREME:
352 return true;
353 default:
354 return false;
355 }
356}
357
358static long fcntl_get_rw_hint(struct file *file, unsigned int cmd,
359 unsigned long arg)
360{
361 struct inode *inode = file_inode(file);
362 u64 __user *argp = (u64 __user *)arg;
363 u64 hint = READ_ONCE(inode->i_write_hint);
364
365 if (copy_to_user(argp, &hint, sizeof(*argp)))
366 return -EFAULT;
367 return 0;
368}
369
370static long fcntl_set_rw_hint(struct file *file, unsigned int cmd,
371 unsigned long arg)
372{
373 struct inode *inode = file_inode(file);
374 u64 __user *argp = (u64 __user *)arg;
375 u64 hint;
376
377 if (!inode_owner_or_capable(file_mnt_idmap(file), inode))
378 return -EPERM;
379
380 if (copy_from_user(&hint, argp, sizeof(hint)))
381 return -EFAULT;
382 if (!rw_hint_valid(hint))
383 return -EINVAL;
384
385 WRITE_ONCE(inode->i_write_hint, hint);
386
387 /*
388 * file->f_mapping->host may differ from inode. As an example,
389 * blkdev_open() modifies file->f_mapping.
390 */
391 if (file->f_mapping->host != inode)
392 WRITE_ONCE(file->f_mapping->host->i_write_hint, hint);
393
394 return 0;
395}
396
397/* Is the file descriptor a dup of the file? */
398static long f_dupfd_query(int fd, struct file *filp)
399{
400 CLASS(fd_raw, f)(fd);
401
402 if (fd_empty(f))
403 return -EBADF;
404
405 /*
406 * We can do the 'fdput()' immediately, as the only thing that
407 * matters is the pointer value which isn't changed by the fdput.
408 *
409 * Technically we didn't need a ref at all, and 'fdget()' was
410 * overkill, but given our lockless file pointer lookup, the
411 * alternatives are complicated.
412 */
413 return fd_file(f) == filp;
414}
415
416/* Let the caller figure out whether a given file was just created. */
417static long f_created_query(const struct file *filp)
418{
419 return !!(filp->f_mode & FMODE_CREATED);
420}
421
422static int f_owner_sig(struct file *filp, int signum, bool setsig)
423{
424 int ret = 0;
425 struct fown_struct *f_owner;
426
427 might_sleep();
428
429 if (setsig) {
430 if (!valid_signal(signum))
431 return -EINVAL;
432
433 ret = file_f_owner_allocate(filp);
434 if (ret)
435 return ret;
436 }
437
438 f_owner = file_f_owner(filp);
439 if (setsig)
440 f_owner->signum = signum;
441 else if (f_owner)
442 ret = f_owner->signum;
443 return ret;
444}
445
446static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
447 struct file *filp)
448{
449 void __user *argp = (void __user *)arg;
450 int argi = (int)arg;
451 struct flock flock;
452 long err = -EINVAL;
453
454 switch (cmd) {
455 case F_CREATED_QUERY:
456 err = f_created_query(filp);
457 break;
458 case F_DUPFD:
459 err = f_dupfd(argi, filp, 0);
460 break;
461 case F_DUPFD_CLOEXEC:
462 err = f_dupfd(argi, filp, O_CLOEXEC);
463 break;
464 case F_DUPFD_QUERY:
465 err = f_dupfd_query(argi, filp);
466 break;
467 case F_GETFD:
468 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
469 break;
470 case F_SETFD:
471 err = 0;
472 set_close_on_exec(fd, argi & FD_CLOEXEC);
473 break;
474 case F_GETFL:
475 err = filp->f_flags;
476 break;
477 case F_SETFL:
478 err = setfl(fd, filp, argi);
479 break;
480#if BITS_PER_LONG != 32
481 /* 32-bit arches must use fcntl64() */
482 case F_OFD_GETLK:
483#endif
484 case F_GETLK:
485 if (copy_from_user(&flock, argp, sizeof(flock)))
486 return -EFAULT;
487 err = fcntl_getlk(filp, cmd, &flock);
488 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
489 return -EFAULT;
490 break;
491#if BITS_PER_LONG != 32
492 /* 32-bit arches must use fcntl64() */
493 case F_OFD_SETLK:
494 case F_OFD_SETLKW:
495 fallthrough;
496#endif
497 case F_SETLK:
498 case F_SETLKW:
499 if (copy_from_user(&flock, argp, sizeof(flock)))
500 return -EFAULT;
501 err = fcntl_setlk(fd, filp, cmd, &flock);
502 break;
503 case F_GETOWN:
504 /*
505 * XXX If f_owner is a process group, the
506 * negative return value will get converted
507 * into an error. Oops. If we keep the
508 * current syscall conventions, the only way
509 * to fix this will be in libc.
510 */
511 err = f_getown(filp);
512 force_successful_syscall_return();
513 break;
514 case F_SETOWN:
515 err = f_setown(filp, argi, 1);
516 break;
517 case F_GETOWN_EX:
518 err = f_getown_ex(filp, arg);
519 break;
520 case F_SETOWN_EX:
521 err = f_setown_ex(filp, arg);
522 break;
523 case F_GETOWNER_UIDS:
524 err = f_getowner_uids(filp, arg);
525 break;
526 case F_GETSIG:
527 err = f_owner_sig(filp, 0, false);
528 break;
529 case F_SETSIG:
530 err = f_owner_sig(filp, argi, true);
531 break;
532 case F_GETLEASE:
533 err = fcntl_getlease(filp);
534 break;
535 case F_SETLEASE:
536 err = fcntl_setlease(fd, filp, argi);
537 break;
538 case F_NOTIFY:
539 err = fcntl_dirnotify(fd, filp, argi);
540 break;
541 case F_SETPIPE_SZ:
542 case F_GETPIPE_SZ:
543 err = pipe_fcntl(filp, cmd, argi);
544 break;
545 case F_ADD_SEALS:
546 case F_GET_SEALS:
547 err = memfd_fcntl(filp, cmd, argi);
548 break;
549 case F_GET_RW_HINT:
550 err = fcntl_get_rw_hint(filp, cmd, arg);
551 break;
552 case F_SET_RW_HINT:
553 err = fcntl_set_rw_hint(filp, cmd, arg);
554 break;
555 default:
556 break;
557 }
558 return err;
559}
560
561static int check_fcntl_cmd(unsigned cmd)
562{
563 switch (cmd) {
564 case F_CREATED_QUERY:
565 case F_DUPFD:
566 case F_DUPFD_CLOEXEC:
567 case F_DUPFD_QUERY:
568 case F_GETFD:
569 case F_SETFD:
570 case F_GETFL:
571 return 1;
572 }
573 return 0;
574}
575
576SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
577{
578 CLASS(fd_raw, f)(fd);
579 long err;
580
581 if (fd_empty(f))
582 return -EBADF;
583
584 if (unlikely(fd_file(f)->f_mode & FMODE_PATH)) {
585 if (!check_fcntl_cmd(cmd))
586 return -EBADF;
587 }
588
589 err = security_file_fcntl(fd_file(f), cmd, arg);
590 if (!err)
591 err = do_fcntl(fd, cmd, arg, fd_file(f));
592
593 return err;
594}
595
596#if BITS_PER_LONG == 32
597SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
598 unsigned long, arg)
599{
600 void __user *argp = (void __user *)arg;
601 CLASS(fd_raw, f)(fd);
602 struct flock64 flock;
603 long err;
604
605 if (fd_empty(f))
606 return -EBADF;
607
608 if (unlikely(fd_file(f)->f_mode & FMODE_PATH)) {
609 if (!check_fcntl_cmd(cmd))
610 return -EBADF;
611 }
612
613 err = security_file_fcntl(fd_file(f), cmd, arg);
614 if (err)
615 return err;
616
617 switch (cmd) {
618 case F_GETLK64:
619 case F_OFD_GETLK:
620 err = -EFAULT;
621 if (copy_from_user(&flock, argp, sizeof(flock)))
622 break;
623 err = fcntl_getlk64(fd_file(f), cmd, &flock);
624 if (!err && copy_to_user(argp, &flock, sizeof(flock)))
625 err = -EFAULT;
626 break;
627 case F_SETLK64:
628 case F_SETLKW64:
629 case F_OFD_SETLK:
630 case F_OFD_SETLKW:
631 err = -EFAULT;
632 if (copy_from_user(&flock, argp, sizeof(flock)))
633 break;
634 err = fcntl_setlk64(fd, fd_file(f), cmd, &flock);
635 break;
636 default:
637 err = do_fcntl(fd, cmd, arg, fd_file(f));
638 break;
639 }
640 return err;
641}
642#endif
643
644#ifdef CONFIG_COMPAT
645/* careful - don't use anywhere else */
646#define copy_flock_fields(dst, src) \
647 (dst)->l_type = (src)->l_type; \
648 (dst)->l_whence = (src)->l_whence; \
649 (dst)->l_start = (src)->l_start; \
650 (dst)->l_len = (src)->l_len; \
651 (dst)->l_pid = (src)->l_pid;
652
653static int get_compat_flock(struct flock *kfl, const struct compat_flock __user *ufl)
654{
655 struct compat_flock fl;
656
657 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock)))
658 return -EFAULT;
659 copy_flock_fields(kfl, &fl);
660 return 0;
661}
662
663static int get_compat_flock64(struct flock *kfl, const struct compat_flock64 __user *ufl)
664{
665 struct compat_flock64 fl;
666
667 if (copy_from_user(&fl, ufl, sizeof(struct compat_flock64)))
668 return -EFAULT;
669 copy_flock_fields(kfl, &fl);
670 return 0;
671}
672
673static int put_compat_flock(const struct flock *kfl, struct compat_flock __user *ufl)
674{
675 struct compat_flock fl;
676
677 memset(&fl, 0, sizeof(struct compat_flock));
678 copy_flock_fields(&fl, kfl);
679 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock)))
680 return -EFAULT;
681 return 0;
682}
683
684static int put_compat_flock64(const struct flock *kfl, struct compat_flock64 __user *ufl)
685{
686 struct compat_flock64 fl;
687
688 BUILD_BUG_ON(sizeof(kfl->l_start) > sizeof(ufl->l_start));
689 BUILD_BUG_ON(sizeof(kfl->l_len) > sizeof(ufl->l_len));
690
691 memset(&fl, 0, sizeof(struct compat_flock64));
692 copy_flock_fields(&fl, kfl);
693 if (copy_to_user(ufl, &fl, sizeof(struct compat_flock64)))
694 return -EFAULT;
695 return 0;
696}
697#undef copy_flock_fields
698
699static unsigned int
700convert_fcntl_cmd(unsigned int cmd)
701{
702 switch (cmd) {
703 case F_GETLK64:
704 return F_GETLK;
705 case F_SETLK64:
706 return F_SETLK;
707 case F_SETLKW64:
708 return F_SETLKW;
709 }
710
711 return cmd;
712}
713
714/*
715 * GETLK was successful and we need to return the data, but it needs to fit in
716 * the compat structure.
717 * l_start shouldn't be too big, unless the original start + end is greater than
718 * COMPAT_OFF_T_MAX, in which case the app was asking for trouble, so we return
719 * -EOVERFLOW in that case. l_len could be too big, in which case we just
720 * truncate it, and only allow the app to see that part of the conflicting lock
721 * that might make sense to it anyway
722 */
723static int fixup_compat_flock(struct flock *flock)
724{
725 if (flock->l_start > COMPAT_OFF_T_MAX)
726 return -EOVERFLOW;
727 if (flock->l_len > COMPAT_OFF_T_MAX)
728 flock->l_len = COMPAT_OFF_T_MAX;
729 return 0;
730}
731
732static long do_compat_fcntl64(unsigned int fd, unsigned int cmd,
733 compat_ulong_t arg)
734{
735 CLASS(fd_raw, f)(fd);
736 struct flock flock;
737 long err;
738
739 if (fd_empty(f))
740 return -EBADF;
741
742 if (unlikely(fd_file(f)->f_mode & FMODE_PATH)) {
743 if (!check_fcntl_cmd(cmd))
744 return -EBADF;
745 }
746
747 err = security_file_fcntl(fd_file(f), cmd, arg);
748 if (err)
749 return err;
750
751 switch (cmd) {
752 case F_GETLK:
753 err = get_compat_flock(&flock, compat_ptr(arg));
754 if (err)
755 break;
756 err = fcntl_getlk(fd_file(f), convert_fcntl_cmd(cmd), &flock);
757 if (err)
758 break;
759 err = fixup_compat_flock(&flock);
760 if (!err)
761 err = put_compat_flock(&flock, compat_ptr(arg));
762 break;
763 case F_GETLK64:
764 case F_OFD_GETLK:
765 err = get_compat_flock64(&flock, compat_ptr(arg));
766 if (err)
767 break;
768 err = fcntl_getlk(fd_file(f), convert_fcntl_cmd(cmd), &flock);
769 if (!err)
770 err = put_compat_flock64(&flock, compat_ptr(arg));
771 break;
772 case F_SETLK:
773 case F_SETLKW:
774 err = get_compat_flock(&flock, compat_ptr(arg));
775 if (err)
776 break;
777 err = fcntl_setlk(fd, fd_file(f), convert_fcntl_cmd(cmd), &flock);
778 break;
779 case F_SETLK64:
780 case F_SETLKW64:
781 case F_OFD_SETLK:
782 case F_OFD_SETLKW:
783 err = get_compat_flock64(&flock, compat_ptr(arg));
784 if (err)
785 break;
786 err = fcntl_setlk(fd, fd_file(f), convert_fcntl_cmd(cmd), &flock);
787 break;
788 default:
789 err = do_fcntl(fd, cmd, arg, fd_file(f));
790 break;
791 }
792 return err;
793}
794
795COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
796 compat_ulong_t, arg)
797{
798 return do_compat_fcntl64(fd, cmd, arg);
799}
800
801COMPAT_SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd,
802 compat_ulong_t, arg)
803{
804 switch (cmd) {
805 case F_GETLK64:
806 case F_SETLK64:
807 case F_SETLKW64:
808 case F_OFD_GETLK:
809 case F_OFD_SETLK:
810 case F_OFD_SETLKW:
811 return -EINVAL;
812 }
813 return do_compat_fcntl64(fd, cmd, arg);
814}
815#endif
816
817/* Table to convert sigio signal codes into poll band bitmaps */
818
819static const __poll_t band_table[NSIGPOLL] = {
820 EPOLLIN | EPOLLRDNORM, /* POLL_IN */
821 EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND, /* POLL_OUT */
822 EPOLLIN | EPOLLRDNORM | EPOLLMSG, /* POLL_MSG */
823 EPOLLERR, /* POLL_ERR */
824 EPOLLPRI | EPOLLRDBAND, /* POLL_PRI */
825 EPOLLHUP | EPOLLERR /* POLL_HUP */
826};
827
828static inline int sigio_perm(struct task_struct *p,
829 struct fown_struct *fown, int sig)
830{
831 const struct cred *cred;
832 int ret;
833
834 rcu_read_lock();
835 cred = __task_cred(p);
836 ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) ||
837 uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) ||
838 uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) &&
839 !security_file_send_sigiotask(p, fown, sig));
840 rcu_read_unlock();
841 return ret;
842}
843
844static void send_sigio_to_task(struct task_struct *p,
845 struct fown_struct *fown,
846 int fd, int reason, enum pid_type type)
847{
848 /*
849 * F_SETSIG can change ->signum lockless in parallel, make
850 * sure we read it once and use the same value throughout.
851 */
852 int signum = READ_ONCE(fown->signum);
853
854 if (!sigio_perm(p, fown, signum))
855 return;
856
857 switch (signum) {
858 default: {
859 kernel_siginfo_t si;
860
861 /* Queue a rt signal with the appropriate fd as its
862 value. We use SI_SIGIO as the source, not
863 SI_KERNEL, since kernel signals always get
864 delivered even if we can't queue. Failure to
865 queue in this case _should_ be reported; we fall
866 back to SIGIO in that case. --sct */
867 clear_siginfo(&si);
868 si.si_signo = signum;
869 si.si_errno = 0;
870 si.si_code = reason;
871 /*
872 * Posix definies POLL_IN and friends to be signal
873 * specific si_codes for SIG_POLL. Linux extended
874 * these si_codes to other signals in a way that is
875 * ambiguous if other signals also have signal
876 * specific si_codes. In that case use SI_SIGIO instead
877 * to remove the ambiguity.
878 */
879 if ((signum != SIGPOLL) && sig_specific_sicodes(signum))
880 si.si_code = SI_SIGIO;
881
882 /* Make sure we are called with one of the POLL_*
883 reasons, otherwise we could leak kernel stack into
884 userspace. */
885 BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL));
886 if (reason - POLL_IN >= NSIGPOLL)
887 si.si_band = ~0L;
888 else
889 si.si_band = mangle_poll(band_table[reason - POLL_IN]);
890 si.si_fd = fd;
891 if (!do_send_sig_info(signum, &si, p, type))
892 break;
893 }
894 fallthrough; /* fall back on the old plain SIGIO signal */
895 case 0:
896 do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type);
897 }
898}
899
900void send_sigio(struct fown_struct *fown, int fd, int band)
901{
902 struct task_struct *p;
903 enum pid_type type;
904 unsigned long flags;
905 struct pid *pid;
906
907 read_lock_irqsave(&fown->lock, flags);
908
909 type = fown->pid_type;
910 pid = fown->pid;
911 if (!pid)
912 goto out_unlock_fown;
913
914 if (type <= PIDTYPE_TGID) {
915 rcu_read_lock();
916 p = pid_task(pid, PIDTYPE_PID);
917 if (p)
918 send_sigio_to_task(p, fown, fd, band, type);
919 rcu_read_unlock();
920 } else {
921 read_lock(&tasklist_lock);
922 do_each_pid_task(pid, type, p) {
923 send_sigio_to_task(p, fown, fd, band, type);
924 } while_each_pid_task(pid, type, p);
925 read_unlock(&tasklist_lock);
926 }
927 out_unlock_fown:
928 read_unlock_irqrestore(&fown->lock, flags);
929}
930
931static void send_sigurg_to_task(struct task_struct *p,
932 struct fown_struct *fown, enum pid_type type)
933{
934 if (sigio_perm(p, fown, SIGURG))
935 do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, type);
936}
937
938int send_sigurg(struct file *file)
939{
940 struct fown_struct *fown;
941 struct task_struct *p;
942 enum pid_type type;
943 struct pid *pid;
944 unsigned long flags;
945 int ret = 0;
946
947 fown = file_f_owner(file);
948 if (!fown)
949 return 0;
950
951 read_lock_irqsave(&fown->lock, flags);
952
953 type = fown->pid_type;
954 pid = fown->pid;
955 if (!pid)
956 goto out_unlock_fown;
957
958 ret = 1;
959
960 if (type <= PIDTYPE_TGID) {
961 rcu_read_lock();
962 p = pid_task(pid, PIDTYPE_PID);
963 if (p)
964 send_sigurg_to_task(p, fown, type);
965 rcu_read_unlock();
966 } else {
967 read_lock(&tasklist_lock);
968 do_each_pid_task(pid, type, p) {
969 send_sigurg_to_task(p, fown, type);
970 } while_each_pid_task(pid, type, p);
971 read_unlock(&tasklist_lock);
972 }
973 out_unlock_fown:
974 read_unlock_irqrestore(&fown->lock, flags);
975 return ret;
976}
977
978static DEFINE_SPINLOCK(fasync_lock);
979static struct kmem_cache *fasync_cache __ro_after_init;
980
981/*
982 * Remove a fasync entry. If successfully removed, return
983 * positive and clear the FASYNC flag. If no entry exists,
984 * do nothing and return 0.
985 *
986 * NOTE! It is very important that the FASYNC flag always
987 * match the state "is the filp on a fasync list".
988 *
989 */
990int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
991{
992 struct fasync_struct *fa, **fp;
993 int result = 0;
994
995 spin_lock(&filp->f_lock);
996 spin_lock(&fasync_lock);
997 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
998 if (fa->fa_file != filp)
999 continue;
1000
1001 write_lock_irq(&fa->fa_lock);
1002 fa->fa_file = NULL;
1003 write_unlock_irq(&fa->fa_lock);
1004
1005 *fp = fa->fa_next;
1006 kfree_rcu(fa, fa_rcu);
1007 filp->f_flags &= ~FASYNC;
1008 result = 1;
1009 break;
1010 }
1011 spin_unlock(&fasync_lock);
1012 spin_unlock(&filp->f_lock);
1013 return result;
1014}
1015
1016struct fasync_struct *fasync_alloc(void)
1017{
1018 return kmem_cache_alloc(fasync_cache, GFP_KERNEL);
1019}
1020
1021/*
1022 * NOTE! This can be used only for unused fasync entries:
1023 * entries that actually got inserted on the fasync list
1024 * need to be released by rcu - see fasync_remove_entry.
1025 */
1026void fasync_free(struct fasync_struct *new)
1027{
1028 kmem_cache_free(fasync_cache, new);
1029}
1030
1031/*
1032 * Insert a new entry into the fasync list. Return the pointer to the
1033 * old one if we didn't use the new one.
1034 *
1035 * NOTE! It is very important that the FASYNC flag always
1036 * match the state "is the filp on a fasync list".
1037 */
1038struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new)
1039{
1040 struct fasync_struct *fa, **fp;
1041
1042 spin_lock(&filp->f_lock);
1043 spin_lock(&fasync_lock);
1044 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
1045 if (fa->fa_file != filp)
1046 continue;
1047
1048 write_lock_irq(&fa->fa_lock);
1049 fa->fa_fd = fd;
1050 write_unlock_irq(&fa->fa_lock);
1051 goto out;
1052 }
1053
1054 rwlock_init(&new->fa_lock);
1055 new->magic = FASYNC_MAGIC;
1056 new->fa_file = filp;
1057 new->fa_fd = fd;
1058 new->fa_next = *fapp;
1059 rcu_assign_pointer(*fapp, new);
1060 filp->f_flags |= FASYNC;
1061
1062out:
1063 spin_unlock(&fasync_lock);
1064 spin_unlock(&filp->f_lock);
1065 return fa;
1066}
1067
1068/*
1069 * Add a fasync entry. Return negative on error, positive if
1070 * added, and zero if did nothing but change an existing one.
1071 */
1072static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
1073{
1074 struct fasync_struct *new;
1075
1076 new = fasync_alloc();
1077 if (!new)
1078 return -ENOMEM;
1079
1080 /*
1081 * fasync_insert_entry() returns the old (update) entry if
1082 * it existed.
1083 *
1084 * So free the (unused) new entry and return 0 to let the
1085 * caller know that we didn't add any new fasync entries.
1086 */
1087 if (fasync_insert_entry(fd, filp, fapp, new)) {
1088 fasync_free(new);
1089 return 0;
1090 }
1091
1092 return 1;
1093}
1094
1095/*
1096 * fasync_helper() is used by almost all character device drivers
1097 * to set up the fasync queue, and for regular files by the file
1098 * lease code. It returns negative on error, 0 if it did no changes
1099 * and positive if it added/deleted the entry.
1100 */
1101int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
1102{
1103 if (!on)
1104 return fasync_remove_entry(filp, fapp);
1105 return fasync_add_entry(fd, filp, fapp);
1106}
1107
1108EXPORT_SYMBOL(fasync_helper);
1109
1110/*
1111 * rcu_read_lock() is held
1112 */
1113static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band)
1114{
1115 while (fa) {
1116 struct fown_struct *fown;
1117 unsigned long flags;
1118
1119 if (fa->magic != FASYNC_MAGIC) {
1120 printk(KERN_ERR "kill_fasync: bad magic number in "
1121 "fasync_struct!\n");
1122 return;
1123 }
1124 read_lock_irqsave(&fa->fa_lock, flags);
1125 if (fa->fa_file) {
1126 fown = file_f_owner(fa->fa_file);
1127 if (!fown)
1128 goto next;
1129 /* Don't send SIGURG to processes which have not set a
1130 queued signum: SIGURG has its own default signalling
1131 mechanism. */
1132 if (!(sig == SIGURG && fown->signum == 0))
1133 send_sigio(fown, fa->fa_fd, band);
1134 }
1135next:
1136 read_unlock_irqrestore(&fa->fa_lock, flags);
1137 fa = rcu_dereference(fa->fa_next);
1138 }
1139}
1140
1141void kill_fasync(struct fasync_struct **fp, int sig, int band)
1142{
1143 /* First a quick test without locking: usually
1144 * the list is empty.
1145 */
1146 if (*fp) {
1147 rcu_read_lock();
1148 kill_fasync_rcu(rcu_dereference(*fp), sig, band);
1149 rcu_read_unlock();
1150 }
1151}
1152EXPORT_SYMBOL(kill_fasync);
1153
1154static int __init fcntl_init(void)
1155{
1156 /*
1157 * Please add new bits here to ensure allocation uniqueness.
1158 * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY
1159 * is defined as O_NONBLOCK on some platforms and not on others.
1160 */
1161 BUILD_BUG_ON(21 - 1 /* for O_RDONLY being 0 */ !=
1162 HWEIGHT32(
1163 (VALID_OPEN_FLAGS & ~(O_NONBLOCK | O_NDELAY)) |
1164 __FMODE_EXEC | __FMODE_NONOTIFY));
1165
1166 fasync_cache = kmem_cache_create("fasync_cache",
1167 sizeof(struct fasync_struct), 0,
1168 SLAB_PANIC | SLAB_ACCOUNT, NULL);
1169 return 0;
1170}
1171
1172module_init(fcntl_init)