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