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reboot: disable usermodehelper to prevent fs access
[mirror_ubuntu-artful-kernel.git] / kernel / sys.c
1 /*
2 * linux/kernel/sys.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/module.h>
8 #include <linux/mm.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/notifier.h>
12 #include <linux/reboot.h>
13 #include <linux/prctl.h>
14 #include <linux/highuid.h>
15 #include <linux/fs.h>
16 #include <linux/perf_event.h>
17 #include <linux/resource.h>
18 #include <linux/kernel.h>
19 #include <linux/kexec.h>
20 #include <linux/workqueue.h>
21 #include <linux/capability.h>
22 #include <linux/device.h>
23 #include <linux/key.h>
24 #include <linux/times.h>
25 #include <linux/posix-timers.h>
26 #include <linux/security.h>
27 #include <linux/dcookies.h>
28 #include <linux/suspend.h>
29 #include <linux/tty.h>
30 #include <linux/signal.h>
31 #include <linux/cn_proc.h>
32 #include <linux/getcpu.h>
33 #include <linux/task_io_accounting_ops.h>
34 #include <linux/seccomp.h>
35 #include <linux/cpu.h>
36 #include <linux/personality.h>
37 #include <linux/ptrace.h>
38 #include <linux/fs_struct.h>
39 #include <linux/gfp.h>
40 #include <linux/syscore_ops.h>
41
42 #include <linux/compat.h>
43 #include <linux/syscalls.h>
44 #include <linux/kprobes.h>
45 #include <linux/user_namespace.h>
46
47 #include <linux/kmsg_dump.h>
48
49 #include <asm/uaccess.h>
50 #include <asm/io.h>
51 #include <asm/unistd.h>
52
53 #ifndef SET_UNALIGN_CTL
54 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
55 #endif
56 #ifndef GET_UNALIGN_CTL
57 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
58 #endif
59 #ifndef SET_FPEMU_CTL
60 # define SET_FPEMU_CTL(a,b) (-EINVAL)
61 #endif
62 #ifndef GET_FPEMU_CTL
63 # define GET_FPEMU_CTL(a,b) (-EINVAL)
64 #endif
65 #ifndef SET_FPEXC_CTL
66 # define SET_FPEXC_CTL(a,b) (-EINVAL)
67 #endif
68 #ifndef GET_FPEXC_CTL
69 # define GET_FPEXC_CTL(a,b) (-EINVAL)
70 #endif
71 #ifndef GET_ENDIAN
72 # define GET_ENDIAN(a,b) (-EINVAL)
73 #endif
74 #ifndef SET_ENDIAN
75 # define SET_ENDIAN(a,b) (-EINVAL)
76 #endif
77 #ifndef GET_TSC_CTL
78 # define GET_TSC_CTL(a) (-EINVAL)
79 #endif
80 #ifndef SET_TSC_CTL
81 # define SET_TSC_CTL(a) (-EINVAL)
82 #endif
83
84 /*
85 * this is where the system-wide overflow UID and GID are defined, for
86 * architectures that now have 32-bit UID/GID but didn't in the past
87 */
88
89 int overflowuid = DEFAULT_OVERFLOWUID;
90 int overflowgid = DEFAULT_OVERFLOWGID;
91
92 #ifdef CONFIG_UID16
93 EXPORT_SYMBOL(overflowuid);
94 EXPORT_SYMBOL(overflowgid);
95 #endif
96
97 /*
98 * the same as above, but for filesystems which can only store a 16-bit
99 * UID and GID. as such, this is needed on all architectures
100 */
101
102 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
103 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
104
105 EXPORT_SYMBOL(fs_overflowuid);
106 EXPORT_SYMBOL(fs_overflowgid);
107
108 /*
109 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
110 */
111
112 int C_A_D = 1;
113 struct pid *cad_pid;
114 EXPORT_SYMBOL(cad_pid);
115
116 /*
117 * If set, this is used for preparing the system to power off.
118 */
119
120 void (*pm_power_off_prepare)(void);
121
122 /*
123 * Returns true if current's euid is same as p's uid or euid,
124 * or has CAP_SYS_NICE to p's user_ns.
125 *
126 * Called with rcu_read_lock, creds are safe
127 */
128 static bool set_one_prio_perm(struct task_struct *p)
129 {
130 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
131
132 if (pcred->user->user_ns == cred->user->user_ns &&
133 (pcred->uid == cred->euid ||
134 pcred->euid == cred->euid))
135 return true;
136 if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
137 return true;
138 return false;
139 }
140
141 /*
142 * set the priority of a task
143 * - the caller must hold the RCU read lock
144 */
145 static int set_one_prio(struct task_struct *p, int niceval, int error)
146 {
147 int no_nice;
148
149 if (!set_one_prio_perm(p)) {
150 error = -EPERM;
151 goto out;
152 }
153 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
154 error = -EACCES;
155 goto out;
156 }
157 no_nice = security_task_setnice(p, niceval);
158 if (no_nice) {
159 error = no_nice;
160 goto out;
161 }
162 if (error == -ESRCH)
163 error = 0;
164 set_user_nice(p, niceval);
165 out:
166 return error;
167 }
168
169 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
170 {
171 struct task_struct *g, *p;
172 struct user_struct *user;
173 const struct cred *cred = current_cred();
174 int error = -EINVAL;
175 struct pid *pgrp;
176
177 if (which > PRIO_USER || which < PRIO_PROCESS)
178 goto out;
179
180 /* normalize: avoid signed division (rounding problems) */
181 error = -ESRCH;
182 if (niceval < -20)
183 niceval = -20;
184 if (niceval > 19)
185 niceval = 19;
186
187 rcu_read_lock();
188 read_lock(&tasklist_lock);
189 switch (which) {
190 case PRIO_PROCESS:
191 if (who)
192 p = find_task_by_vpid(who);
193 else
194 p = current;
195 if (p)
196 error = set_one_prio(p, niceval, error);
197 break;
198 case PRIO_PGRP:
199 if (who)
200 pgrp = find_vpid(who);
201 else
202 pgrp = task_pgrp(current);
203 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
204 error = set_one_prio(p, niceval, error);
205 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
206 break;
207 case PRIO_USER:
208 user = (struct user_struct *) cred->user;
209 if (!who)
210 who = cred->uid;
211 else if ((who != cred->uid) &&
212 !(user = find_user(who)))
213 goto out_unlock; /* No processes for this user */
214
215 do_each_thread(g, p) {
216 if (__task_cred(p)->uid == who)
217 error = set_one_prio(p, niceval, error);
218 } while_each_thread(g, p);
219 if (who != cred->uid)
220 free_uid(user); /* For find_user() */
221 break;
222 }
223 out_unlock:
224 read_unlock(&tasklist_lock);
225 rcu_read_unlock();
226 out:
227 return error;
228 }
229
230 /*
231 * Ugh. To avoid negative return values, "getpriority()" will
232 * not return the normal nice-value, but a negated value that
233 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
234 * to stay compatible.
235 */
236 SYSCALL_DEFINE2(getpriority, int, which, int, who)
237 {
238 struct task_struct *g, *p;
239 struct user_struct *user;
240 const struct cred *cred = current_cred();
241 long niceval, retval = -ESRCH;
242 struct pid *pgrp;
243
244 if (which > PRIO_USER || which < PRIO_PROCESS)
245 return -EINVAL;
246
247 rcu_read_lock();
248 read_lock(&tasklist_lock);
249 switch (which) {
250 case PRIO_PROCESS:
251 if (who)
252 p = find_task_by_vpid(who);
253 else
254 p = current;
255 if (p) {
256 niceval = 20 - task_nice(p);
257 if (niceval > retval)
258 retval = niceval;
259 }
260 break;
261 case PRIO_PGRP:
262 if (who)
263 pgrp = find_vpid(who);
264 else
265 pgrp = task_pgrp(current);
266 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
267 niceval = 20 - task_nice(p);
268 if (niceval > retval)
269 retval = niceval;
270 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
271 break;
272 case PRIO_USER:
273 user = (struct user_struct *) cred->user;
274 if (!who)
275 who = cred->uid;
276 else if ((who != cred->uid) &&
277 !(user = find_user(who)))
278 goto out_unlock; /* No processes for this user */
279
280 do_each_thread(g, p) {
281 if (__task_cred(p)->uid == who) {
282 niceval = 20 - task_nice(p);
283 if (niceval > retval)
284 retval = niceval;
285 }
286 } while_each_thread(g, p);
287 if (who != cred->uid)
288 free_uid(user); /* for find_user() */
289 break;
290 }
291 out_unlock:
292 read_unlock(&tasklist_lock);
293 rcu_read_unlock();
294
295 return retval;
296 }
297
298 /**
299 * emergency_restart - reboot the system
300 *
301 * Without shutting down any hardware or taking any locks
302 * reboot the system. This is called when we know we are in
303 * trouble so this is our best effort to reboot. This is
304 * safe to call in interrupt context.
305 */
306 void emergency_restart(void)
307 {
308 kmsg_dump(KMSG_DUMP_EMERG);
309 machine_emergency_restart();
310 }
311 EXPORT_SYMBOL_GPL(emergency_restart);
312
313 void kernel_restart_prepare(char *cmd)
314 {
315 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
316 system_state = SYSTEM_RESTART;
317 usermodehelper_disable();
318 device_shutdown();
319 sysdev_shutdown();
320 syscore_shutdown();
321 }
322
323 /**
324 * kernel_restart - reboot the system
325 * @cmd: pointer to buffer containing command to execute for restart
326 * or %NULL
327 *
328 * Shutdown everything and perform a clean reboot.
329 * This is not safe to call in interrupt context.
330 */
331 void kernel_restart(char *cmd)
332 {
333 kernel_restart_prepare(cmd);
334 if (!cmd)
335 printk(KERN_EMERG "Restarting system.\n");
336 else
337 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
338 kmsg_dump(KMSG_DUMP_RESTART);
339 machine_restart(cmd);
340 }
341 EXPORT_SYMBOL_GPL(kernel_restart);
342
343 static void kernel_shutdown_prepare(enum system_states state)
344 {
345 blocking_notifier_call_chain(&reboot_notifier_list,
346 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
347 system_state = state;
348 usermodehelper_disable();
349 device_shutdown();
350 }
351 /**
352 * kernel_halt - halt the system
353 *
354 * Shutdown everything and perform a clean system halt.
355 */
356 void kernel_halt(void)
357 {
358 kernel_shutdown_prepare(SYSTEM_HALT);
359 sysdev_shutdown();
360 syscore_shutdown();
361 printk(KERN_EMERG "System halted.\n");
362 kmsg_dump(KMSG_DUMP_HALT);
363 machine_halt();
364 }
365
366 EXPORT_SYMBOL_GPL(kernel_halt);
367
368 /**
369 * kernel_power_off - power_off the system
370 *
371 * Shutdown everything and perform a clean system power_off.
372 */
373 void kernel_power_off(void)
374 {
375 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
376 if (pm_power_off_prepare)
377 pm_power_off_prepare();
378 disable_nonboot_cpus();
379 sysdev_shutdown();
380 syscore_shutdown();
381 printk(KERN_EMERG "Power down.\n");
382 kmsg_dump(KMSG_DUMP_POWEROFF);
383 machine_power_off();
384 }
385 EXPORT_SYMBOL_GPL(kernel_power_off);
386
387 static DEFINE_MUTEX(reboot_mutex);
388
389 /*
390 * Reboot system call: for obvious reasons only root may call it,
391 * and even root needs to set up some magic numbers in the registers
392 * so that some mistake won't make this reboot the whole machine.
393 * You can also set the meaning of the ctrl-alt-del-key here.
394 *
395 * reboot doesn't sync: do that yourself before calling this.
396 */
397 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
398 void __user *, arg)
399 {
400 char buffer[256];
401 int ret = 0;
402
403 /* We only trust the superuser with rebooting the system. */
404 if (!capable(CAP_SYS_BOOT))
405 return -EPERM;
406
407 /* For safety, we require "magic" arguments. */
408 if (magic1 != LINUX_REBOOT_MAGIC1 ||
409 (magic2 != LINUX_REBOOT_MAGIC2 &&
410 magic2 != LINUX_REBOOT_MAGIC2A &&
411 magic2 != LINUX_REBOOT_MAGIC2B &&
412 magic2 != LINUX_REBOOT_MAGIC2C))
413 return -EINVAL;
414
415 /* Instead of trying to make the power_off code look like
416 * halt when pm_power_off is not set do it the easy way.
417 */
418 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
419 cmd = LINUX_REBOOT_CMD_HALT;
420
421 mutex_lock(&reboot_mutex);
422 switch (cmd) {
423 case LINUX_REBOOT_CMD_RESTART:
424 kernel_restart(NULL);
425 break;
426
427 case LINUX_REBOOT_CMD_CAD_ON:
428 C_A_D = 1;
429 break;
430
431 case LINUX_REBOOT_CMD_CAD_OFF:
432 C_A_D = 0;
433 break;
434
435 case LINUX_REBOOT_CMD_HALT:
436 kernel_halt();
437 do_exit(0);
438 panic("cannot halt");
439
440 case LINUX_REBOOT_CMD_POWER_OFF:
441 kernel_power_off();
442 do_exit(0);
443 break;
444
445 case LINUX_REBOOT_CMD_RESTART2:
446 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
447 ret = -EFAULT;
448 break;
449 }
450 buffer[sizeof(buffer) - 1] = '\0';
451
452 kernel_restart(buffer);
453 break;
454
455 #ifdef CONFIG_KEXEC
456 case LINUX_REBOOT_CMD_KEXEC:
457 ret = kernel_kexec();
458 break;
459 #endif
460
461 #ifdef CONFIG_HIBERNATION
462 case LINUX_REBOOT_CMD_SW_SUSPEND:
463 ret = hibernate();
464 break;
465 #endif
466
467 default:
468 ret = -EINVAL;
469 break;
470 }
471 mutex_unlock(&reboot_mutex);
472 return ret;
473 }
474
475 static void deferred_cad(struct work_struct *dummy)
476 {
477 kernel_restart(NULL);
478 }
479
480 /*
481 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
482 * As it's called within an interrupt, it may NOT sync: the only choice
483 * is whether to reboot at once, or just ignore the ctrl-alt-del.
484 */
485 void ctrl_alt_del(void)
486 {
487 static DECLARE_WORK(cad_work, deferred_cad);
488
489 if (C_A_D)
490 schedule_work(&cad_work);
491 else
492 kill_cad_pid(SIGINT, 1);
493 }
494
495 /*
496 * Unprivileged users may change the real gid to the effective gid
497 * or vice versa. (BSD-style)
498 *
499 * If you set the real gid at all, or set the effective gid to a value not
500 * equal to the real gid, then the saved gid is set to the new effective gid.
501 *
502 * This makes it possible for a setgid program to completely drop its
503 * privileges, which is often a useful assertion to make when you are doing
504 * a security audit over a program.
505 *
506 * The general idea is that a program which uses just setregid() will be
507 * 100% compatible with BSD. A program which uses just setgid() will be
508 * 100% compatible with POSIX with saved IDs.
509 *
510 * SMP: There are not races, the GIDs are checked only by filesystem
511 * operations (as far as semantic preservation is concerned).
512 */
513 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
514 {
515 const struct cred *old;
516 struct cred *new;
517 int retval;
518
519 new = prepare_creds();
520 if (!new)
521 return -ENOMEM;
522 old = current_cred();
523
524 retval = -EPERM;
525 if (rgid != (gid_t) -1) {
526 if (old->gid == rgid ||
527 old->egid == rgid ||
528 nsown_capable(CAP_SETGID))
529 new->gid = rgid;
530 else
531 goto error;
532 }
533 if (egid != (gid_t) -1) {
534 if (old->gid == egid ||
535 old->egid == egid ||
536 old->sgid == egid ||
537 nsown_capable(CAP_SETGID))
538 new->egid = egid;
539 else
540 goto error;
541 }
542
543 if (rgid != (gid_t) -1 ||
544 (egid != (gid_t) -1 && egid != old->gid))
545 new->sgid = new->egid;
546 new->fsgid = new->egid;
547
548 return commit_creds(new);
549
550 error:
551 abort_creds(new);
552 return retval;
553 }
554
555 /*
556 * setgid() is implemented like SysV w/ SAVED_IDS
557 *
558 * SMP: Same implicit races as above.
559 */
560 SYSCALL_DEFINE1(setgid, gid_t, gid)
561 {
562 const struct cred *old;
563 struct cred *new;
564 int retval;
565
566 new = prepare_creds();
567 if (!new)
568 return -ENOMEM;
569 old = current_cred();
570
571 retval = -EPERM;
572 if (nsown_capable(CAP_SETGID))
573 new->gid = new->egid = new->sgid = new->fsgid = gid;
574 else if (gid == old->gid || gid == old->sgid)
575 new->egid = new->fsgid = gid;
576 else
577 goto error;
578
579 return commit_creds(new);
580
581 error:
582 abort_creds(new);
583 return retval;
584 }
585
586 /*
587 * change the user struct in a credentials set to match the new UID
588 */
589 static int set_user(struct cred *new)
590 {
591 struct user_struct *new_user;
592
593 new_user = alloc_uid(current_user_ns(), new->uid);
594 if (!new_user)
595 return -EAGAIN;
596
597 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
598 new_user != INIT_USER) {
599 free_uid(new_user);
600 return -EAGAIN;
601 }
602
603 free_uid(new->user);
604 new->user = new_user;
605 return 0;
606 }
607
608 /*
609 * Unprivileged users may change the real uid to the effective uid
610 * or vice versa. (BSD-style)
611 *
612 * If you set the real uid at all, or set the effective uid to a value not
613 * equal to the real uid, then the saved uid is set to the new effective uid.
614 *
615 * This makes it possible for a setuid program to completely drop its
616 * privileges, which is often a useful assertion to make when you are doing
617 * a security audit over a program.
618 *
619 * The general idea is that a program which uses just setreuid() will be
620 * 100% compatible with BSD. A program which uses just setuid() will be
621 * 100% compatible with POSIX with saved IDs.
622 */
623 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
624 {
625 const struct cred *old;
626 struct cred *new;
627 int retval;
628
629 new = prepare_creds();
630 if (!new)
631 return -ENOMEM;
632 old = current_cred();
633
634 retval = -EPERM;
635 if (ruid != (uid_t) -1) {
636 new->uid = ruid;
637 if (old->uid != ruid &&
638 old->euid != ruid &&
639 !nsown_capable(CAP_SETUID))
640 goto error;
641 }
642
643 if (euid != (uid_t) -1) {
644 new->euid = euid;
645 if (old->uid != euid &&
646 old->euid != euid &&
647 old->suid != euid &&
648 !nsown_capable(CAP_SETUID))
649 goto error;
650 }
651
652 if (new->uid != old->uid) {
653 retval = set_user(new);
654 if (retval < 0)
655 goto error;
656 }
657 if (ruid != (uid_t) -1 ||
658 (euid != (uid_t) -1 && euid != old->uid))
659 new->suid = new->euid;
660 new->fsuid = new->euid;
661
662 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
663 if (retval < 0)
664 goto error;
665
666 return commit_creds(new);
667
668 error:
669 abort_creds(new);
670 return retval;
671 }
672
673 /*
674 * setuid() is implemented like SysV with SAVED_IDS
675 *
676 * Note that SAVED_ID's is deficient in that a setuid root program
677 * like sendmail, for example, cannot set its uid to be a normal
678 * user and then switch back, because if you're root, setuid() sets
679 * the saved uid too. If you don't like this, blame the bright people
680 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
681 * will allow a root program to temporarily drop privileges and be able to
682 * regain them by swapping the real and effective uid.
683 */
684 SYSCALL_DEFINE1(setuid, uid_t, uid)
685 {
686 const struct cred *old;
687 struct cred *new;
688 int retval;
689
690 new = prepare_creds();
691 if (!new)
692 return -ENOMEM;
693 old = current_cred();
694
695 retval = -EPERM;
696 if (nsown_capable(CAP_SETUID)) {
697 new->suid = new->uid = uid;
698 if (uid != old->uid) {
699 retval = set_user(new);
700 if (retval < 0)
701 goto error;
702 }
703 } else if (uid != old->uid && uid != new->suid) {
704 goto error;
705 }
706
707 new->fsuid = new->euid = uid;
708
709 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
710 if (retval < 0)
711 goto error;
712
713 return commit_creds(new);
714
715 error:
716 abort_creds(new);
717 return retval;
718 }
719
720
721 /*
722 * This function implements a generic ability to update ruid, euid,
723 * and suid. This allows you to implement the 4.4 compatible seteuid().
724 */
725 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
726 {
727 const struct cred *old;
728 struct cred *new;
729 int retval;
730
731 new = prepare_creds();
732 if (!new)
733 return -ENOMEM;
734
735 old = current_cred();
736
737 retval = -EPERM;
738 if (!nsown_capable(CAP_SETUID)) {
739 if (ruid != (uid_t) -1 && ruid != old->uid &&
740 ruid != old->euid && ruid != old->suid)
741 goto error;
742 if (euid != (uid_t) -1 && euid != old->uid &&
743 euid != old->euid && euid != old->suid)
744 goto error;
745 if (suid != (uid_t) -1 && suid != old->uid &&
746 suid != old->euid && suid != old->suid)
747 goto error;
748 }
749
750 if (ruid != (uid_t) -1) {
751 new->uid = ruid;
752 if (ruid != old->uid) {
753 retval = set_user(new);
754 if (retval < 0)
755 goto error;
756 }
757 }
758 if (euid != (uid_t) -1)
759 new->euid = euid;
760 if (suid != (uid_t) -1)
761 new->suid = suid;
762 new->fsuid = new->euid;
763
764 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
765 if (retval < 0)
766 goto error;
767
768 return commit_creds(new);
769
770 error:
771 abort_creds(new);
772 return retval;
773 }
774
775 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
776 {
777 const struct cred *cred = current_cred();
778 int retval;
779
780 if (!(retval = put_user(cred->uid, ruid)) &&
781 !(retval = put_user(cred->euid, euid)))
782 retval = put_user(cred->suid, suid);
783
784 return retval;
785 }
786
787 /*
788 * Same as above, but for rgid, egid, sgid.
789 */
790 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
791 {
792 const struct cred *old;
793 struct cred *new;
794 int retval;
795
796 new = prepare_creds();
797 if (!new)
798 return -ENOMEM;
799 old = current_cred();
800
801 retval = -EPERM;
802 if (!nsown_capable(CAP_SETGID)) {
803 if (rgid != (gid_t) -1 && rgid != old->gid &&
804 rgid != old->egid && rgid != old->sgid)
805 goto error;
806 if (egid != (gid_t) -1 && egid != old->gid &&
807 egid != old->egid && egid != old->sgid)
808 goto error;
809 if (sgid != (gid_t) -1 && sgid != old->gid &&
810 sgid != old->egid && sgid != old->sgid)
811 goto error;
812 }
813
814 if (rgid != (gid_t) -1)
815 new->gid = rgid;
816 if (egid != (gid_t) -1)
817 new->egid = egid;
818 if (sgid != (gid_t) -1)
819 new->sgid = sgid;
820 new->fsgid = new->egid;
821
822 return commit_creds(new);
823
824 error:
825 abort_creds(new);
826 return retval;
827 }
828
829 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
830 {
831 const struct cred *cred = current_cred();
832 int retval;
833
834 if (!(retval = put_user(cred->gid, rgid)) &&
835 !(retval = put_user(cred->egid, egid)))
836 retval = put_user(cred->sgid, sgid);
837
838 return retval;
839 }
840
841
842 /*
843 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
844 * is used for "access()" and for the NFS daemon (letting nfsd stay at
845 * whatever uid it wants to). It normally shadows "euid", except when
846 * explicitly set by setfsuid() or for access..
847 */
848 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
849 {
850 const struct cred *old;
851 struct cred *new;
852 uid_t old_fsuid;
853
854 new = prepare_creds();
855 if (!new)
856 return current_fsuid();
857 old = current_cred();
858 old_fsuid = old->fsuid;
859
860 if (uid == old->uid || uid == old->euid ||
861 uid == old->suid || uid == old->fsuid ||
862 nsown_capable(CAP_SETUID)) {
863 if (uid != old_fsuid) {
864 new->fsuid = uid;
865 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
866 goto change_okay;
867 }
868 }
869
870 abort_creds(new);
871 return old_fsuid;
872
873 change_okay:
874 commit_creds(new);
875 return old_fsuid;
876 }
877
878 /*
879 * Samma på svenska..
880 */
881 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
882 {
883 const struct cred *old;
884 struct cred *new;
885 gid_t old_fsgid;
886
887 new = prepare_creds();
888 if (!new)
889 return current_fsgid();
890 old = current_cred();
891 old_fsgid = old->fsgid;
892
893 if (gid == old->gid || gid == old->egid ||
894 gid == old->sgid || gid == old->fsgid ||
895 nsown_capable(CAP_SETGID)) {
896 if (gid != old_fsgid) {
897 new->fsgid = gid;
898 goto change_okay;
899 }
900 }
901
902 abort_creds(new);
903 return old_fsgid;
904
905 change_okay:
906 commit_creds(new);
907 return old_fsgid;
908 }
909
910 void do_sys_times(struct tms *tms)
911 {
912 cputime_t tgutime, tgstime, cutime, cstime;
913
914 spin_lock_irq(&current->sighand->siglock);
915 thread_group_times(current, &tgutime, &tgstime);
916 cutime = current->signal->cutime;
917 cstime = current->signal->cstime;
918 spin_unlock_irq(&current->sighand->siglock);
919 tms->tms_utime = cputime_to_clock_t(tgutime);
920 tms->tms_stime = cputime_to_clock_t(tgstime);
921 tms->tms_cutime = cputime_to_clock_t(cutime);
922 tms->tms_cstime = cputime_to_clock_t(cstime);
923 }
924
925 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
926 {
927 if (tbuf) {
928 struct tms tmp;
929
930 do_sys_times(&tmp);
931 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
932 return -EFAULT;
933 }
934 force_successful_syscall_return();
935 return (long) jiffies_64_to_clock_t(get_jiffies_64());
936 }
937
938 /*
939 * This needs some heavy checking ...
940 * I just haven't the stomach for it. I also don't fully
941 * understand sessions/pgrp etc. Let somebody who does explain it.
942 *
943 * OK, I think I have the protection semantics right.... this is really
944 * only important on a multi-user system anyway, to make sure one user
945 * can't send a signal to a process owned by another. -TYT, 12/12/91
946 *
947 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
948 * LBT 04.03.94
949 */
950 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
951 {
952 struct task_struct *p;
953 struct task_struct *group_leader = current->group_leader;
954 struct pid *pgrp;
955 int err;
956
957 if (!pid)
958 pid = task_pid_vnr(group_leader);
959 if (!pgid)
960 pgid = pid;
961 if (pgid < 0)
962 return -EINVAL;
963 rcu_read_lock();
964
965 /* From this point forward we keep holding onto the tasklist lock
966 * so that our parent does not change from under us. -DaveM
967 */
968 write_lock_irq(&tasklist_lock);
969
970 err = -ESRCH;
971 p = find_task_by_vpid(pid);
972 if (!p)
973 goto out;
974
975 err = -EINVAL;
976 if (!thread_group_leader(p))
977 goto out;
978
979 if (same_thread_group(p->real_parent, group_leader)) {
980 err = -EPERM;
981 if (task_session(p) != task_session(group_leader))
982 goto out;
983 err = -EACCES;
984 if (p->did_exec)
985 goto out;
986 } else {
987 err = -ESRCH;
988 if (p != group_leader)
989 goto out;
990 }
991
992 err = -EPERM;
993 if (p->signal->leader)
994 goto out;
995
996 pgrp = task_pid(p);
997 if (pgid != pid) {
998 struct task_struct *g;
999
1000 pgrp = find_vpid(pgid);
1001 g = pid_task(pgrp, PIDTYPE_PGID);
1002 if (!g || task_session(g) != task_session(group_leader))
1003 goto out;
1004 }
1005
1006 err = security_task_setpgid(p, pgid);
1007 if (err)
1008 goto out;
1009
1010 if (task_pgrp(p) != pgrp)
1011 change_pid(p, PIDTYPE_PGID, pgrp);
1012
1013 err = 0;
1014 out:
1015 /* All paths lead to here, thus we are safe. -DaveM */
1016 write_unlock_irq(&tasklist_lock);
1017 rcu_read_unlock();
1018 return err;
1019 }
1020
1021 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1022 {
1023 struct task_struct *p;
1024 struct pid *grp;
1025 int retval;
1026
1027 rcu_read_lock();
1028 if (!pid)
1029 grp = task_pgrp(current);
1030 else {
1031 retval = -ESRCH;
1032 p = find_task_by_vpid(pid);
1033 if (!p)
1034 goto out;
1035 grp = task_pgrp(p);
1036 if (!grp)
1037 goto out;
1038
1039 retval = security_task_getpgid(p);
1040 if (retval)
1041 goto out;
1042 }
1043 retval = pid_vnr(grp);
1044 out:
1045 rcu_read_unlock();
1046 return retval;
1047 }
1048
1049 #ifdef __ARCH_WANT_SYS_GETPGRP
1050
1051 SYSCALL_DEFINE0(getpgrp)
1052 {
1053 return sys_getpgid(0);
1054 }
1055
1056 #endif
1057
1058 SYSCALL_DEFINE1(getsid, pid_t, pid)
1059 {
1060 struct task_struct *p;
1061 struct pid *sid;
1062 int retval;
1063
1064 rcu_read_lock();
1065 if (!pid)
1066 sid = task_session(current);
1067 else {
1068 retval = -ESRCH;
1069 p = find_task_by_vpid(pid);
1070 if (!p)
1071 goto out;
1072 sid = task_session(p);
1073 if (!sid)
1074 goto out;
1075
1076 retval = security_task_getsid(p);
1077 if (retval)
1078 goto out;
1079 }
1080 retval = pid_vnr(sid);
1081 out:
1082 rcu_read_unlock();
1083 return retval;
1084 }
1085
1086 SYSCALL_DEFINE0(setsid)
1087 {
1088 struct task_struct *group_leader = current->group_leader;
1089 struct pid *sid = task_pid(group_leader);
1090 pid_t session = pid_vnr(sid);
1091 int err = -EPERM;
1092
1093 write_lock_irq(&tasklist_lock);
1094 /* Fail if I am already a session leader */
1095 if (group_leader->signal->leader)
1096 goto out;
1097
1098 /* Fail if a process group id already exists that equals the
1099 * proposed session id.
1100 */
1101 if (pid_task(sid, PIDTYPE_PGID))
1102 goto out;
1103
1104 group_leader->signal->leader = 1;
1105 __set_special_pids(sid);
1106
1107 proc_clear_tty(group_leader);
1108
1109 err = session;
1110 out:
1111 write_unlock_irq(&tasklist_lock);
1112 if (err > 0) {
1113 proc_sid_connector(group_leader);
1114 sched_autogroup_create_attach(group_leader);
1115 }
1116 return err;
1117 }
1118
1119 DECLARE_RWSEM(uts_sem);
1120
1121 #ifdef COMPAT_UTS_MACHINE
1122 #define override_architecture(name) \
1123 (personality(current->personality) == PER_LINUX32 && \
1124 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1125 sizeof(COMPAT_UTS_MACHINE)))
1126 #else
1127 #define override_architecture(name) 0
1128 #endif
1129
1130 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1131 {
1132 int errno = 0;
1133
1134 down_read(&uts_sem);
1135 if (copy_to_user(name, utsname(), sizeof *name))
1136 errno = -EFAULT;
1137 up_read(&uts_sem);
1138
1139 if (!errno && override_architecture(name))
1140 errno = -EFAULT;
1141 return errno;
1142 }
1143
1144 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1145 /*
1146 * Old cruft
1147 */
1148 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1149 {
1150 int error = 0;
1151
1152 if (!name)
1153 return -EFAULT;
1154
1155 down_read(&uts_sem);
1156 if (copy_to_user(name, utsname(), sizeof(*name)))
1157 error = -EFAULT;
1158 up_read(&uts_sem);
1159
1160 if (!error && override_architecture(name))
1161 error = -EFAULT;
1162 return error;
1163 }
1164
1165 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1166 {
1167 int error;
1168
1169 if (!name)
1170 return -EFAULT;
1171 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1172 return -EFAULT;
1173
1174 down_read(&uts_sem);
1175 error = __copy_to_user(&name->sysname, &utsname()->sysname,
1176 __OLD_UTS_LEN);
1177 error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1178 error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1179 __OLD_UTS_LEN);
1180 error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1181 error |= __copy_to_user(&name->release, &utsname()->release,
1182 __OLD_UTS_LEN);
1183 error |= __put_user(0, name->release + __OLD_UTS_LEN);
1184 error |= __copy_to_user(&name->version, &utsname()->version,
1185 __OLD_UTS_LEN);
1186 error |= __put_user(0, name->version + __OLD_UTS_LEN);
1187 error |= __copy_to_user(&name->machine, &utsname()->machine,
1188 __OLD_UTS_LEN);
1189 error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1190 up_read(&uts_sem);
1191
1192 if (!error && override_architecture(name))
1193 error = -EFAULT;
1194 return error ? -EFAULT : 0;
1195 }
1196 #endif
1197
1198 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1199 {
1200 int errno;
1201 char tmp[__NEW_UTS_LEN];
1202
1203 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1204 return -EPERM;
1205
1206 if (len < 0 || len > __NEW_UTS_LEN)
1207 return -EINVAL;
1208 down_write(&uts_sem);
1209 errno = -EFAULT;
1210 if (!copy_from_user(tmp, name, len)) {
1211 struct new_utsname *u = utsname();
1212
1213 memcpy(u->nodename, tmp, len);
1214 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1215 errno = 0;
1216 }
1217 up_write(&uts_sem);
1218 return errno;
1219 }
1220
1221 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1222
1223 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1224 {
1225 int i, errno;
1226 struct new_utsname *u;
1227
1228 if (len < 0)
1229 return -EINVAL;
1230 down_read(&uts_sem);
1231 u = utsname();
1232 i = 1 + strlen(u->nodename);
1233 if (i > len)
1234 i = len;
1235 errno = 0;
1236 if (copy_to_user(name, u->nodename, i))
1237 errno = -EFAULT;
1238 up_read(&uts_sem);
1239 return errno;
1240 }
1241
1242 #endif
1243
1244 /*
1245 * Only setdomainname; getdomainname can be implemented by calling
1246 * uname()
1247 */
1248 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1249 {
1250 int errno;
1251 char tmp[__NEW_UTS_LEN];
1252
1253 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1254 return -EPERM;
1255 if (len < 0 || len > __NEW_UTS_LEN)
1256 return -EINVAL;
1257
1258 down_write(&uts_sem);
1259 errno = -EFAULT;
1260 if (!copy_from_user(tmp, name, len)) {
1261 struct new_utsname *u = utsname();
1262
1263 memcpy(u->domainname, tmp, len);
1264 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1265 errno = 0;
1266 }
1267 up_write(&uts_sem);
1268 return errno;
1269 }
1270
1271 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1272 {
1273 struct rlimit value;
1274 int ret;
1275
1276 ret = do_prlimit(current, resource, NULL, &value);
1277 if (!ret)
1278 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1279
1280 return ret;
1281 }
1282
1283 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1284
1285 /*
1286 * Back compatibility for getrlimit. Needed for some apps.
1287 */
1288
1289 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1290 struct rlimit __user *, rlim)
1291 {
1292 struct rlimit x;
1293 if (resource >= RLIM_NLIMITS)
1294 return -EINVAL;
1295
1296 task_lock(current->group_leader);
1297 x = current->signal->rlim[resource];
1298 task_unlock(current->group_leader);
1299 if (x.rlim_cur > 0x7FFFFFFF)
1300 x.rlim_cur = 0x7FFFFFFF;
1301 if (x.rlim_max > 0x7FFFFFFF)
1302 x.rlim_max = 0x7FFFFFFF;
1303 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1304 }
1305
1306 #endif
1307
1308 static inline bool rlim64_is_infinity(__u64 rlim64)
1309 {
1310 #if BITS_PER_LONG < 64
1311 return rlim64 >= ULONG_MAX;
1312 #else
1313 return rlim64 == RLIM64_INFINITY;
1314 #endif
1315 }
1316
1317 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1318 {
1319 if (rlim->rlim_cur == RLIM_INFINITY)
1320 rlim64->rlim_cur = RLIM64_INFINITY;
1321 else
1322 rlim64->rlim_cur = rlim->rlim_cur;
1323 if (rlim->rlim_max == RLIM_INFINITY)
1324 rlim64->rlim_max = RLIM64_INFINITY;
1325 else
1326 rlim64->rlim_max = rlim->rlim_max;
1327 }
1328
1329 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1330 {
1331 if (rlim64_is_infinity(rlim64->rlim_cur))
1332 rlim->rlim_cur = RLIM_INFINITY;
1333 else
1334 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1335 if (rlim64_is_infinity(rlim64->rlim_max))
1336 rlim->rlim_max = RLIM_INFINITY;
1337 else
1338 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1339 }
1340
1341 /* make sure you are allowed to change @tsk limits before calling this */
1342 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1343 struct rlimit *new_rlim, struct rlimit *old_rlim)
1344 {
1345 struct rlimit *rlim;
1346 int retval = 0;
1347
1348 if (resource >= RLIM_NLIMITS)
1349 return -EINVAL;
1350 if (new_rlim) {
1351 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1352 return -EINVAL;
1353 if (resource == RLIMIT_NOFILE &&
1354 new_rlim->rlim_max > sysctl_nr_open)
1355 return -EPERM;
1356 }
1357
1358 /* protect tsk->signal and tsk->sighand from disappearing */
1359 read_lock(&tasklist_lock);
1360 if (!tsk->sighand) {
1361 retval = -ESRCH;
1362 goto out;
1363 }
1364
1365 rlim = tsk->signal->rlim + resource;
1366 task_lock(tsk->group_leader);
1367 if (new_rlim) {
1368 /* Keep the capable check against init_user_ns until
1369 cgroups can contain all limits */
1370 if (new_rlim->rlim_max > rlim->rlim_max &&
1371 !capable(CAP_SYS_RESOURCE))
1372 retval = -EPERM;
1373 if (!retval)
1374 retval = security_task_setrlimit(tsk->group_leader,
1375 resource, new_rlim);
1376 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1377 /*
1378 * The caller is asking for an immediate RLIMIT_CPU
1379 * expiry. But we use the zero value to mean "it was
1380 * never set". So let's cheat and make it one second
1381 * instead
1382 */
1383 new_rlim->rlim_cur = 1;
1384 }
1385 }
1386 if (!retval) {
1387 if (old_rlim)
1388 *old_rlim = *rlim;
1389 if (new_rlim)
1390 *rlim = *new_rlim;
1391 }
1392 task_unlock(tsk->group_leader);
1393
1394 /*
1395 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1396 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1397 * very long-standing error, and fixing it now risks breakage of
1398 * applications, so we live with it
1399 */
1400 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1401 new_rlim->rlim_cur != RLIM_INFINITY)
1402 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1403 out:
1404 read_unlock(&tasklist_lock);
1405 return retval;
1406 }
1407
1408 /* rcu lock must be held */
1409 static int check_prlimit_permission(struct task_struct *task)
1410 {
1411 const struct cred *cred = current_cred(), *tcred;
1412
1413 if (current == task)
1414 return 0;
1415
1416 tcred = __task_cred(task);
1417 if (cred->user->user_ns == tcred->user->user_ns &&
1418 (cred->uid == tcred->euid &&
1419 cred->uid == tcred->suid &&
1420 cred->uid == tcred->uid &&
1421 cred->gid == tcred->egid &&
1422 cred->gid == tcred->sgid &&
1423 cred->gid == tcred->gid))
1424 return 0;
1425 if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1426 return 0;
1427
1428 return -EPERM;
1429 }
1430
1431 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1432 const struct rlimit64 __user *, new_rlim,
1433 struct rlimit64 __user *, old_rlim)
1434 {
1435 struct rlimit64 old64, new64;
1436 struct rlimit old, new;
1437 struct task_struct *tsk;
1438 int ret;
1439
1440 if (new_rlim) {
1441 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1442 return -EFAULT;
1443 rlim64_to_rlim(&new64, &new);
1444 }
1445
1446 rcu_read_lock();
1447 tsk = pid ? find_task_by_vpid(pid) : current;
1448 if (!tsk) {
1449 rcu_read_unlock();
1450 return -ESRCH;
1451 }
1452 ret = check_prlimit_permission(tsk);
1453 if (ret) {
1454 rcu_read_unlock();
1455 return ret;
1456 }
1457 get_task_struct(tsk);
1458 rcu_read_unlock();
1459
1460 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1461 old_rlim ? &old : NULL);
1462
1463 if (!ret && old_rlim) {
1464 rlim_to_rlim64(&old, &old64);
1465 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1466 ret = -EFAULT;
1467 }
1468
1469 put_task_struct(tsk);
1470 return ret;
1471 }
1472
1473 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1474 {
1475 struct rlimit new_rlim;
1476
1477 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1478 return -EFAULT;
1479 return do_prlimit(current, resource, &new_rlim, NULL);
1480 }
1481
1482 /*
1483 * It would make sense to put struct rusage in the task_struct,
1484 * except that would make the task_struct be *really big*. After
1485 * task_struct gets moved into malloc'ed memory, it would
1486 * make sense to do this. It will make moving the rest of the information
1487 * a lot simpler! (Which we're not doing right now because we're not
1488 * measuring them yet).
1489 *
1490 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1491 * races with threads incrementing their own counters. But since word
1492 * reads are atomic, we either get new values or old values and we don't
1493 * care which for the sums. We always take the siglock to protect reading
1494 * the c* fields from p->signal from races with exit.c updating those
1495 * fields when reaping, so a sample either gets all the additions of a
1496 * given child after it's reaped, or none so this sample is before reaping.
1497 *
1498 * Locking:
1499 * We need to take the siglock for CHILDEREN, SELF and BOTH
1500 * for the cases current multithreaded, non-current single threaded
1501 * non-current multithreaded. Thread traversal is now safe with
1502 * the siglock held.
1503 * Strictly speaking, we donot need to take the siglock if we are current and
1504 * single threaded, as no one else can take our signal_struct away, no one
1505 * else can reap the children to update signal->c* counters, and no one else
1506 * can race with the signal-> fields. If we do not take any lock, the
1507 * signal-> fields could be read out of order while another thread was just
1508 * exiting. So we should place a read memory barrier when we avoid the lock.
1509 * On the writer side, write memory barrier is implied in __exit_signal
1510 * as __exit_signal releases the siglock spinlock after updating the signal->
1511 * fields. But we don't do this yet to keep things simple.
1512 *
1513 */
1514
1515 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1516 {
1517 r->ru_nvcsw += t->nvcsw;
1518 r->ru_nivcsw += t->nivcsw;
1519 r->ru_minflt += t->min_flt;
1520 r->ru_majflt += t->maj_flt;
1521 r->ru_inblock += task_io_get_inblock(t);
1522 r->ru_oublock += task_io_get_oublock(t);
1523 }
1524
1525 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1526 {
1527 struct task_struct *t;
1528 unsigned long flags;
1529 cputime_t tgutime, tgstime, utime, stime;
1530 unsigned long maxrss = 0;
1531
1532 memset((char *) r, 0, sizeof *r);
1533 utime = stime = cputime_zero;
1534
1535 if (who == RUSAGE_THREAD) {
1536 task_times(current, &utime, &stime);
1537 accumulate_thread_rusage(p, r);
1538 maxrss = p->signal->maxrss;
1539 goto out;
1540 }
1541
1542 if (!lock_task_sighand(p, &flags))
1543 return;
1544
1545 switch (who) {
1546 case RUSAGE_BOTH:
1547 case RUSAGE_CHILDREN:
1548 utime = p->signal->cutime;
1549 stime = p->signal->cstime;
1550 r->ru_nvcsw = p->signal->cnvcsw;
1551 r->ru_nivcsw = p->signal->cnivcsw;
1552 r->ru_minflt = p->signal->cmin_flt;
1553 r->ru_majflt = p->signal->cmaj_flt;
1554 r->ru_inblock = p->signal->cinblock;
1555 r->ru_oublock = p->signal->coublock;
1556 maxrss = p->signal->cmaxrss;
1557
1558 if (who == RUSAGE_CHILDREN)
1559 break;
1560
1561 case RUSAGE_SELF:
1562 thread_group_times(p, &tgutime, &tgstime);
1563 utime = cputime_add(utime, tgutime);
1564 stime = cputime_add(stime, tgstime);
1565 r->ru_nvcsw += p->signal->nvcsw;
1566 r->ru_nivcsw += p->signal->nivcsw;
1567 r->ru_minflt += p->signal->min_flt;
1568 r->ru_majflt += p->signal->maj_flt;
1569 r->ru_inblock += p->signal->inblock;
1570 r->ru_oublock += p->signal->oublock;
1571 if (maxrss < p->signal->maxrss)
1572 maxrss = p->signal->maxrss;
1573 t = p;
1574 do {
1575 accumulate_thread_rusage(t, r);
1576 t = next_thread(t);
1577 } while (t != p);
1578 break;
1579
1580 default:
1581 BUG();
1582 }
1583 unlock_task_sighand(p, &flags);
1584
1585 out:
1586 cputime_to_timeval(utime, &r->ru_utime);
1587 cputime_to_timeval(stime, &r->ru_stime);
1588
1589 if (who != RUSAGE_CHILDREN) {
1590 struct mm_struct *mm = get_task_mm(p);
1591 if (mm) {
1592 setmax_mm_hiwater_rss(&maxrss, mm);
1593 mmput(mm);
1594 }
1595 }
1596 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1597 }
1598
1599 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1600 {
1601 struct rusage r;
1602 k_getrusage(p, who, &r);
1603 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1604 }
1605
1606 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1607 {
1608 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1609 who != RUSAGE_THREAD)
1610 return -EINVAL;
1611 return getrusage(current, who, ru);
1612 }
1613
1614 SYSCALL_DEFINE1(umask, int, mask)
1615 {
1616 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1617 return mask;
1618 }
1619
1620 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1621 unsigned long, arg4, unsigned long, arg5)
1622 {
1623 struct task_struct *me = current;
1624 unsigned char comm[sizeof(me->comm)];
1625 long error;
1626
1627 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1628 if (error != -ENOSYS)
1629 return error;
1630
1631 error = 0;
1632 switch (option) {
1633 case PR_SET_PDEATHSIG:
1634 if (!valid_signal(arg2)) {
1635 error = -EINVAL;
1636 break;
1637 }
1638 me->pdeath_signal = arg2;
1639 error = 0;
1640 break;
1641 case PR_GET_PDEATHSIG:
1642 error = put_user(me->pdeath_signal, (int __user *)arg2);
1643 break;
1644 case PR_GET_DUMPABLE:
1645 error = get_dumpable(me->mm);
1646 break;
1647 case PR_SET_DUMPABLE:
1648 if (arg2 < 0 || arg2 > 1) {
1649 error = -EINVAL;
1650 break;
1651 }
1652 set_dumpable(me->mm, arg2);
1653 error = 0;
1654 break;
1655
1656 case PR_SET_UNALIGN:
1657 error = SET_UNALIGN_CTL(me, arg2);
1658 break;
1659 case PR_GET_UNALIGN:
1660 error = GET_UNALIGN_CTL(me, arg2);
1661 break;
1662 case PR_SET_FPEMU:
1663 error = SET_FPEMU_CTL(me, arg2);
1664 break;
1665 case PR_GET_FPEMU:
1666 error = GET_FPEMU_CTL(me, arg2);
1667 break;
1668 case PR_SET_FPEXC:
1669 error = SET_FPEXC_CTL(me, arg2);
1670 break;
1671 case PR_GET_FPEXC:
1672 error = GET_FPEXC_CTL(me, arg2);
1673 break;
1674 case PR_GET_TIMING:
1675 error = PR_TIMING_STATISTICAL;
1676 break;
1677 case PR_SET_TIMING:
1678 if (arg2 != PR_TIMING_STATISTICAL)
1679 error = -EINVAL;
1680 else
1681 error = 0;
1682 break;
1683
1684 case PR_SET_NAME:
1685 comm[sizeof(me->comm)-1] = 0;
1686 if (strncpy_from_user(comm, (char __user *)arg2,
1687 sizeof(me->comm) - 1) < 0)
1688 return -EFAULT;
1689 set_task_comm(me, comm);
1690 return 0;
1691 case PR_GET_NAME:
1692 get_task_comm(comm, me);
1693 if (copy_to_user((char __user *)arg2, comm,
1694 sizeof(comm)))
1695 return -EFAULT;
1696 return 0;
1697 case PR_GET_ENDIAN:
1698 error = GET_ENDIAN(me, arg2);
1699 break;
1700 case PR_SET_ENDIAN:
1701 error = SET_ENDIAN(me, arg2);
1702 break;
1703
1704 case PR_GET_SECCOMP:
1705 error = prctl_get_seccomp();
1706 break;
1707 case PR_SET_SECCOMP:
1708 error = prctl_set_seccomp(arg2);
1709 break;
1710 case PR_GET_TSC:
1711 error = GET_TSC_CTL(arg2);
1712 break;
1713 case PR_SET_TSC:
1714 error = SET_TSC_CTL(arg2);
1715 break;
1716 case PR_TASK_PERF_EVENTS_DISABLE:
1717 error = perf_event_task_disable();
1718 break;
1719 case PR_TASK_PERF_EVENTS_ENABLE:
1720 error = perf_event_task_enable();
1721 break;
1722 case PR_GET_TIMERSLACK:
1723 error = current->timer_slack_ns;
1724 break;
1725 case PR_SET_TIMERSLACK:
1726 if (arg2 <= 0)
1727 current->timer_slack_ns =
1728 current->default_timer_slack_ns;
1729 else
1730 current->timer_slack_ns = arg2;
1731 error = 0;
1732 break;
1733 case PR_MCE_KILL:
1734 if (arg4 | arg5)
1735 return -EINVAL;
1736 switch (arg2) {
1737 case PR_MCE_KILL_CLEAR:
1738 if (arg3 != 0)
1739 return -EINVAL;
1740 current->flags &= ~PF_MCE_PROCESS;
1741 break;
1742 case PR_MCE_KILL_SET:
1743 current->flags |= PF_MCE_PROCESS;
1744 if (arg3 == PR_MCE_KILL_EARLY)
1745 current->flags |= PF_MCE_EARLY;
1746 else if (arg3 == PR_MCE_KILL_LATE)
1747 current->flags &= ~PF_MCE_EARLY;
1748 else if (arg3 == PR_MCE_KILL_DEFAULT)
1749 current->flags &=
1750 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1751 else
1752 return -EINVAL;
1753 break;
1754 default:
1755 return -EINVAL;
1756 }
1757 error = 0;
1758 break;
1759 case PR_MCE_KILL_GET:
1760 if (arg2 | arg3 | arg4 | arg5)
1761 return -EINVAL;
1762 if (current->flags & PF_MCE_PROCESS)
1763 error = (current->flags & PF_MCE_EARLY) ?
1764 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1765 else
1766 error = PR_MCE_KILL_DEFAULT;
1767 break;
1768 default:
1769 error = -EINVAL;
1770 break;
1771 }
1772 return error;
1773 }
1774
1775 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1776 struct getcpu_cache __user *, unused)
1777 {
1778 int err = 0;
1779 int cpu = raw_smp_processor_id();
1780 if (cpup)
1781 err |= put_user(cpu, cpup);
1782 if (nodep)
1783 err |= put_user(cpu_to_node(cpu), nodep);
1784 return err ? -EFAULT : 0;
1785 }
1786
1787 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1788
1789 static void argv_cleanup(struct subprocess_info *info)
1790 {
1791 argv_free(info->argv);
1792 }
1793
1794 /**
1795 * orderly_poweroff - Trigger an orderly system poweroff
1796 * @force: force poweroff if command execution fails
1797 *
1798 * This may be called from any context to trigger a system shutdown.
1799 * If the orderly shutdown fails, it will force an immediate shutdown.
1800 */
1801 int orderly_poweroff(bool force)
1802 {
1803 int argc;
1804 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1805 static char *envp[] = {
1806 "HOME=/",
1807 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1808 NULL
1809 };
1810 int ret = -ENOMEM;
1811 struct subprocess_info *info;
1812
1813 if (argv == NULL) {
1814 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1815 __func__, poweroff_cmd);
1816 goto out;
1817 }
1818
1819 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1820 if (info == NULL) {
1821 argv_free(argv);
1822 goto out;
1823 }
1824
1825 call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1826
1827 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1828
1829 out:
1830 if (ret && force) {
1831 printk(KERN_WARNING "Failed to start orderly shutdown: "
1832 "forcing the issue\n");
1833
1834 /* I guess this should try to kick off some daemon to
1835 sync and poweroff asap. Or not even bother syncing
1836 if we're doing an emergency shutdown? */
1837 emergency_sync();
1838 kernel_power_off();
1839 }
1840
1841 return ret;
1842 }
1843 EXPORT_SYMBOL_GPL(orderly_poweroff);
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