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Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[deliverable/linux.git] / kernel / sys.c
1 /*
2 * linux/kernel/sys.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/export.h>
8 #include <linux/mm.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/reboot.h>
12 #include <linux/prctl.h>
13 #include <linux/highuid.h>
14 #include <linux/fs.h>
15 #include <linux/kmod.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/file.h>
40 #include <linux/mount.h>
41 #include <linux/gfp.h>
42 #include <linux/syscore_ops.h>
43 #include <linux/version.h>
44 #include <linux/ctype.h>
45
46 #include <linux/compat.h>
47 #include <linux/syscalls.h>
48 #include <linux/kprobes.h>
49 #include <linux/user_namespace.h>
50 #include <linux/binfmts.h>
51
52 #include <linux/kmsg_dump.h>
53 /* Move somewhere else to avoid recompiling? */
54 #include <generated/utsrelease.h>
55
56 #include <asm/uaccess.h>
57 #include <asm/io.h>
58 #include <asm/unistd.h>
59
60 #ifndef SET_UNALIGN_CTL
61 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
62 #endif
63 #ifndef GET_UNALIGN_CTL
64 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
65 #endif
66 #ifndef SET_FPEMU_CTL
67 # define SET_FPEMU_CTL(a,b) (-EINVAL)
68 #endif
69 #ifndef GET_FPEMU_CTL
70 # define GET_FPEMU_CTL(a,b) (-EINVAL)
71 #endif
72 #ifndef SET_FPEXC_CTL
73 # define SET_FPEXC_CTL(a,b) (-EINVAL)
74 #endif
75 #ifndef GET_FPEXC_CTL
76 # define GET_FPEXC_CTL(a,b) (-EINVAL)
77 #endif
78 #ifndef GET_ENDIAN
79 # define GET_ENDIAN(a,b) (-EINVAL)
80 #endif
81 #ifndef SET_ENDIAN
82 # define SET_ENDIAN(a,b) (-EINVAL)
83 #endif
84 #ifndef GET_TSC_CTL
85 # define GET_TSC_CTL(a) (-EINVAL)
86 #endif
87 #ifndef SET_TSC_CTL
88 # define SET_TSC_CTL(a) (-EINVAL)
89 #endif
90
91 /*
92 * this is where the system-wide overflow UID and GID are defined, for
93 * architectures that now have 32-bit UID/GID but didn't in the past
94 */
95
96 int overflowuid = DEFAULT_OVERFLOWUID;
97 int overflowgid = DEFAULT_OVERFLOWGID;
98
99 EXPORT_SYMBOL(overflowuid);
100 EXPORT_SYMBOL(overflowgid);
101
102 /*
103 * the same as above, but for filesystems which can only store a 16-bit
104 * UID and GID. as such, this is needed on all architectures
105 */
106
107 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
108 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
109
110 EXPORT_SYMBOL(fs_overflowuid);
111 EXPORT_SYMBOL(fs_overflowgid);
112
113 /*
114 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
115 */
116
117 int C_A_D = 1;
118 struct pid *cad_pid;
119 EXPORT_SYMBOL(cad_pid);
120
121 /*
122 * If set, this is used for preparing the system to power off.
123 */
124
125 void (*pm_power_off_prepare)(void);
126
127 /*
128 * Returns true if current's euid is same as p's uid or euid,
129 * or has CAP_SYS_NICE to p's user_ns.
130 *
131 * Called with rcu_read_lock, creds are safe
132 */
133 static bool set_one_prio_perm(struct task_struct *p)
134 {
135 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
136
137 if (uid_eq(pcred->uid, cred->euid) ||
138 uid_eq(pcred->euid, cred->euid))
139 return true;
140 if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
141 return true;
142 return false;
143 }
144
145 /*
146 * set the priority of a task
147 * - the caller must hold the RCU read lock
148 */
149 static int set_one_prio(struct task_struct *p, int niceval, int error)
150 {
151 int no_nice;
152
153 if (!set_one_prio_perm(p)) {
154 error = -EPERM;
155 goto out;
156 }
157 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
158 error = -EACCES;
159 goto out;
160 }
161 no_nice = security_task_setnice(p, niceval);
162 if (no_nice) {
163 error = no_nice;
164 goto out;
165 }
166 if (error == -ESRCH)
167 error = 0;
168 set_user_nice(p, niceval);
169 out:
170 return error;
171 }
172
173 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
174 {
175 struct task_struct *g, *p;
176 struct user_struct *user;
177 const struct cred *cred = current_cred();
178 int error = -EINVAL;
179 struct pid *pgrp;
180 kuid_t uid;
181
182 if (which > PRIO_USER || which < PRIO_PROCESS)
183 goto out;
184
185 /* normalize: avoid signed division (rounding problems) */
186 error = -ESRCH;
187 if (niceval < -20)
188 niceval = -20;
189 if (niceval > 19)
190 niceval = 19;
191
192 rcu_read_lock();
193 read_lock(&tasklist_lock);
194 switch (which) {
195 case PRIO_PROCESS:
196 if (who)
197 p = find_task_by_vpid(who);
198 else
199 p = current;
200 if (p)
201 error = set_one_prio(p, niceval, error);
202 break;
203 case PRIO_PGRP:
204 if (who)
205 pgrp = find_vpid(who);
206 else
207 pgrp = task_pgrp(current);
208 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
209 error = set_one_prio(p, niceval, error);
210 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
211 break;
212 case PRIO_USER:
213 uid = make_kuid(cred->user_ns, who);
214 user = cred->user;
215 if (!who)
216 uid = cred->uid;
217 else if (!uid_eq(uid, cred->uid) &&
218 !(user = find_user(uid)))
219 goto out_unlock; /* No processes for this user */
220
221 do_each_thread(g, p) {
222 if (uid_eq(task_uid(p), uid))
223 error = set_one_prio(p, niceval, error);
224 } while_each_thread(g, p);
225 if (!uid_eq(uid, cred->uid))
226 free_uid(user); /* For find_user() */
227 break;
228 }
229 out_unlock:
230 read_unlock(&tasklist_lock);
231 rcu_read_unlock();
232 out:
233 return error;
234 }
235
236 /*
237 * Ugh. To avoid negative return values, "getpriority()" will
238 * not return the normal nice-value, but a negated value that
239 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
240 * to stay compatible.
241 */
242 SYSCALL_DEFINE2(getpriority, int, which, int, who)
243 {
244 struct task_struct *g, *p;
245 struct user_struct *user;
246 const struct cred *cred = current_cred();
247 long niceval, retval = -ESRCH;
248 struct pid *pgrp;
249 kuid_t uid;
250
251 if (which > PRIO_USER || which < PRIO_PROCESS)
252 return -EINVAL;
253
254 rcu_read_lock();
255 read_lock(&tasklist_lock);
256 switch (which) {
257 case PRIO_PROCESS:
258 if (who)
259 p = find_task_by_vpid(who);
260 else
261 p = current;
262 if (p) {
263 niceval = 20 - task_nice(p);
264 if (niceval > retval)
265 retval = niceval;
266 }
267 break;
268 case PRIO_PGRP:
269 if (who)
270 pgrp = find_vpid(who);
271 else
272 pgrp = task_pgrp(current);
273 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
274 niceval = 20 - task_nice(p);
275 if (niceval > retval)
276 retval = niceval;
277 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
278 break;
279 case PRIO_USER:
280 uid = make_kuid(cred->user_ns, who);
281 user = cred->user;
282 if (!who)
283 uid = cred->uid;
284 else if (!uid_eq(uid, cred->uid) &&
285 !(user = find_user(uid)))
286 goto out_unlock; /* No processes for this user */
287
288 do_each_thread(g, p) {
289 if (uid_eq(task_uid(p), uid)) {
290 niceval = 20 - task_nice(p);
291 if (niceval > retval)
292 retval = niceval;
293 }
294 } while_each_thread(g, p);
295 if (!uid_eq(uid, cred->uid))
296 free_uid(user); /* for find_user() */
297 break;
298 }
299 out_unlock:
300 read_unlock(&tasklist_lock);
301 rcu_read_unlock();
302
303 return retval;
304 }
305
306 /**
307 * emergency_restart - reboot the system
308 *
309 * Without shutting down any hardware or taking any locks
310 * reboot the system. This is called when we know we are in
311 * trouble so this is our best effort to reboot. This is
312 * safe to call in interrupt context.
313 */
314 void emergency_restart(void)
315 {
316 kmsg_dump(KMSG_DUMP_EMERG);
317 machine_emergency_restart();
318 }
319 EXPORT_SYMBOL_GPL(emergency_restart);
320
321 void kernel_restart_prepare(char *cmd)
322 {
323 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
324 system_state = SYSTEM_RESTART;
325 usermodehelper_disable();
326 device_shutdown();
327 syscore_shutdown();
328 }
329
330 /**
331 * register_reboot_notifier - Register function to be called at reboot time
332 * @nb: Info about notifier function to be called
333 *
334 * Registers a function with the list of functions
335 * to be called at reboot time.
336 *
337 * Currently always returns zero, as blocking_notifier_chain_register()
338 * always returns zero.
339 */
340 int register_reboot_notifier(struct notifier_block *nb)
341 {
342 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
343 }
344 EXPORT_SYMBOL(register_reboot_notifier);
345
346 /**
347 * unregister_reboot_notifier - Unregister previously registered reboot notifier
348 * @nb: Hook to be unregistered
349 *
350 * Unregisters a previously registered reboot
351 * notifier function.
352 *
353 * Returns zero on success, or %-ENOENT on failure.
354 */
355 int unregister_reboot_notifier(struct notifier_block *nb)
356 {
357 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
358 }
359 EXPORT_SYMBOL(unregister_reboot_notifier);
360
361 /**
362 * kernel_restart - reboot the system
363 * @cmd: pointer to buffer containing command to execute for restart
364 * or %NULL
365 *
366 * Shutdown everything and perform a clean reboot.
367 * This is not safe to call in interrupt context.
368 */
369 void kernel_restart(char *cmd)
370 {
371 kernel_restart_prepare(cmd);
372 disable_nonboot_cpus();
373 if (!cmd)
374 printk(KERN_EMERG "Restarting system.\n");
375 else
376 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
377 kmsg_dump(KMSG_DUMP_RESTART);
378 machine_restart(cmd);
379 }
380 EXPORT_SYMBOL_GPL(kernel_restart);
381
382 static void kernel_shutdown_prepare(enum system_states state)
383 {
384 blocking_notifier_call_chain(&reboot_notifier_list,
385 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
386 system_state = state;
387 usermodehelper_disable();
388 device_shutdown();
389 }
390 /**
391 * kernel_halt - halt the system
392 *
393 * Shutdown everything and perform a clean system halt.
394 */
395 void kernel_halt(void)
396 {
397 kernel_shutdown_prepare(SYSTEM_HALT);
398 syscore_shutdown();
399 printk(KERN_EMERG "System halted.\n");
400 kmsg_dump(KMSG_DUMP_HALT);
401 machine_halt();
402 }
403
404 EXPORT_SYMBOL_GPL(kernel_halt);
405
406 /**
407 * kernel_power_off - power_off the system
408 *
409 * Shutdown everything and perform a clean system power_off.
410 */
411 void kernel_power_off(void)
412 {
413 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
414 if (pm_power_off_prepare)
415 pm_power_off_prepare();
416 disable_nonboot_cpus();
417 syscore_shutdown();
418 printk(KERN_EMERG "Power down.\n");
419 kmsg_dump(KMSG_DUMP_POWEROFF);
420 machine_power_off();
421 }
422 EXPORT_SYMBOL_GPL(kernel_power_off);
423
424 static DEFINE_MUTEX(reboot_mutex);
425
426 /*
427 * Reboot system call: for obvious reasons only root may call it,
428 * and even root needs to set up some magic numbers in the registers
429 * so that some mistake won't make this reboot the whole machine.
430 * You can also set the meaning of the ctrl-alt-del-key here.
431 *
432 * reboot doesn't sync: do that yourself before calling this.
433 */
434 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
435 void __user *, arg)
436 {
437 char buffer[256];
438 int ret = 0;
439
440 /* We only trust the superuser with rebooting the system. */
441 if (!capable(CAP_SYS_BOOT))
442 return -EPERM;
443
444 /* For safety, we require "magic" arguments. */
445 if (magic1 != LINUX_REBOOT_MAGIC1 ||
446 (magic2 != LINUX_REBOOT_MAGIC2 &&
447 magic2 != LINUX_REBOOT_MAGIC2A &&
448 magic2 != LINUX_REBOOT_MAGIC2B &&
449 magic2 != LINUX_REBOOT_MAGIC2C))
450 return -EINVAL;
451
452 /*
453 * If pid namespaces are enabled and the current task is in a child
454 * pid_namespace, the command is handled by reboot_pid_ns() which will
455 * call do_exit().
456 */
457 ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
458 if (ret)
459 return ret;
460
461 /* Instead of trying to make the power_off code look like
462 * halt when pm_power_off is not set do it the easy way.
463 */
464 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
465 cmd = LINUX_REBOOT_CMD_HALT;
466
467 mutex_lock(&reboot_mutex);
468 switch (cmd) {
469 case LINUX_REBOOT_CMD_RESTART:
470 kernel_restart(NULL);
471 break;
472
473 case LINUX_REBOOT_CMD_CAD_ON:
474 C_A_D = 1;
475 break;
476
477 case LINUX_REBOOT_CMD_CAD_OFF:
478 C_A_D = 0;
479 break;
480
481 case LINUX_REBOOT_CMD_HALT:
482 kernel_halt();
483 do_exit(0);
484 panic("cannot halt");
485
486 case LINUX_REBOOT_CMD_POWER_OFF:
487 kernel_power_off();
488 do_exit(0);
489 break;
490
491 case LINUX_REBOOT_CMD_RESTART2:
492 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
493 ret = -EFAULT;
494 break;
495 }
496 buffer[sizeof(buffer) - 1] = '\0';
497
498 kernel_restart(buffer);
499 break;
500
501 #ifdef CONFIG_KEXEC
502 case LINUX_REBOOT_CMD_KEXEC:
503 ret = kernel_kexec();
504 break;
505 #endif
506
507 #ifdef CONFIG_HIBERNATION
508 case LINUX_REBOOT_CMD_SW_SUSPEND:
509 ret = hibernate();
510 break;
511 #endif
512
513 default:
514 ret = -EINVAL;
515 break;
516 }
517 mutex_unlock(&reboot_mutex);
518 return ret;
519 }
520
521 static void deferred_cad(struct work_struct *dummy)
522 {
523 kernel_restart(NULL);
524 }
525
526 /*
527 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
528 * As it's called within an interrupt, it may NOT sync: the only choice
529 * is whether to reboot at once, or just ignore the ctrl-alt-del.
530 */
531 void ctrl_alt_del(void)
532 {
533 static DECLARE_WORK(cad_work, deferred_cad);
534
535 if (C_A_D)
536 schedule_work(&cad_work);
537 else
538 kill_cad_pid(SIGINT, 1);
539 }
540
541 /*
542 * Unprivileged users may change the real gid to the effective gid
543 * or vice versa. (BSD-style)
544 *
545 * If you set the real gid at all, or set the effective gid to a value not
546 * equal to the real gid, then the saved gid is set to the new effective gid.
547 *
548 * This makes it possible for a setgid program to completely drop its
549 * privileges, which is often a useful assertion to make when you are doing
550 * a security audit over a program.
551 *
552 * The general idea is that a program which uses just setregid() will be
553 * 100% compatible with BSD. A program which uses just setgid() will be
554 * 100% compatible with POSIX with saved IDs.
555 *
556 * SMP: There are not races, the GIDs are checked only by filesystem
557 * operations (as far as semantic preservation is concerned).
558 */
559 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
560 {
561 struct user_namespace *ns = current_user_ns();
562 const struct cred *old;
563 struct cred *new;
564 int retval;
565 kgid_t krgid, kegid;
566
567 krgid = make_kgid(ns, rgid);
568 kegid = make_kgid(ns, egid);
569
570 if ((rgid != (gid_t) -1) && !gid_valid(krgid))
571 return -EINVAL;
572 if ((egid != (gid_t) -1) && !gid_valid(kegid))
573 return -EINVAL;
574
575 new = prepare_creds();
576 if (!new)
577 return -ENOMEM;
578 old = current_cred();
579
580 retval = -EPERM;
581 if (rgid != (gid_t) -1) {
582 if (gid_eq(old->gid, krgid) ||
583 gid_eq(old->egid, krgid) ||
584 nsown_capable(CAP_SETGID))
585 new->gid = krgid;
586 else
587 goto error;
588 }
589 if (egid != (gid_t) -1) {
590 if (gid_eq(old->gid, kegid) ||
591 gid_eq(old->egid, kegid) ||
592 gid_eq(old->sgid, kegid) ||
593 nsown_capable(CAP_SETGID))
594 new->egid = kegid;
595 else
596 goto error;
597 }
598
599 if (rgid != (gid_t) -1 ||
600 (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
601 new->sgid = new->egid;
602 new->fsgid = new->egid;
603
604 return commit_creds(new);
605
606 error:
607 abort_creds(new);
608 return retval;
609 }
610
611 /*
612 * setgid() is implemented like SysV w/ SAVED_IDS
613 *
614 * SMP: Same implicit races as above.
615 */
616 SYSCALL_DEFINE1(setgid, gid_t, gid)
617 {
618 struct user_namespace *ns = current_user_ns();
619 const struct cred *old;
620 struct cred *new;
621 int retval;
622 kgid_t kgid;
623
624 kgid = make_kgid(ns, gid);
625 if (!gid_valid(kgid))
626 return -EINVAL;
627
628 new = prepare_creds();
629 if (!new)
630 return -ENOMEM;
631 old = current_cred();
632
633 retval = -EPERM;
634 if (nsown_capable(CAP_SETGID))
635 new->gid = new->egid = new->sgid = new->fsgid = kgid;
636 else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
637 new->egid = new->fsgid = kgid;
638 else
639 goto error;
640
641 return commit_creds(new);
642
643 error:
644 abort_creds(new);
645 return retval;
646 }
647
648 /*
649 * change the user struct in a credentials set to match the new UID
650 */
651 static int set_user(struct cred *new)
652 {
653 struct user_struct *new_user;
654
655 new_user = alloc_uid(new->uid);
656 if (!new_user)
657 return -EAGAIN;
658
659 /*
660 * We don't fail in case of NPROC limit excess here because too many
661 * poorly written programs don't check set*uid() return code, assuming
662 * it never fails if called by root. We may still enforce NPROC limit
663 * for programs doing set*uid()+execve() by harmlessly deferring the
664 * failure to the execve() stage.
665 */
666 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
667 new_user != INIT_USER)
668 current->flags |= PF_NPROC_EXCEEDED;
669 else
670 current->flags &= ~PF_NPROC_EXCEEDED;
671
672 free_uid(new->user);
673 new->user = new_user;
674 return 0;
675 }
676
677 /*
678 * Unprivileged users may change the real uid to the effective uid
679 * or vice versa. (BSD-style)
680 *
681 * If you set the real uid at all, or set the effective uid to a value not
682 * equal to the real uid, then the saved uid is set to the new effective uid.
683 *
684 * This makes it possible for a setuid program to completely drop its
685 * privileges, which is often a useful assertion to make when you are doing
686 * a security audit over a program.
687 *
688 * The general idea is that a program which uses just setreuid() will be
689 * 100% compatible with BSD. A program which uses just setuid() will be
690 * 100% compatible with POSIX with saved IDs.
691 */
692 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
693 {
694 struct user_namespace *ns = current_user_ns();
695 const struct cred *old;
696 struct cred *new;
697 int retval;
698 kuid_t kruid, keuid;
699
700 kruid = make_kuid(ns, ruid);
701 keuid = make_kuid(ns, euid);
702
703 if ((ruid != (uid_t) -1) && !uid_valid(kruid))
704 return -EINVAL;
705 if ((euid != (uid_t) -1) && !uid_valid(keuid))
706 return -EINVAL;
707
708 new = prepare_creds();
709 if (!new)
710 return -ENOMEM;
711 old = current_cred();
712
713 retval = -EPERM;
714 if (ruid != (uid_t) -1) {
715 new->uid = kruid;
716 if (!uid_eq(old->uid, kruid) &&
717 !uid_eq(old->euid, kruid) &&
718 !nsown_capable(CAP_SETUID))
719 goto error;
720 }
721
722 if (euid != (uid_t) -1) {
723 new->euid = keuid;
724 if (!uid_eq(old->uid, keuid) &&
725 !uid_eq(old->euid, keuid) &&
726 !uid_eq(old->suid, keuid) &&
727 !nsown_capable(CAP_SETUID))
728 goto error;
729 }
730
731 if (!uid_eq(new->uid, old->uid)) {
732 retval = set_user(new);
733 if (retval < 0)
734 goto error;
735 }
736 if (ruid != (uid_t) -1 ||
737 (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
738 new->suid = new->euid;
739 new->fsuid = new->euid;
740
741 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
742 if (retval < 0)
743 goto error;
744
745 return commit_creds(new);
746
747 error:
748 abort_creds(new);
749 return retval;
750 }
751
752 /*
753 * setuid() is implemented like SysV with SAVED_IDS
754 *
755 * Note that SAVED_ID's is deficient in that a setuid root program
756 * like sendmail, for example, cannot set its uid to be a normal
757 * user and then switch back, because if you're root, setuid() sets
758 * the saved uid too. If you don't like this, blame the bright people
759 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
760 * will allow a root program to temporarily drop privileges and be able to
761 * regain them by swapping the real and effective uid.
762 */
763 SYSCALL_DEFINE1(setuid, uid_t, uid)
764 {
765 struct user_namespace *ns = current_user_ns();
766 const struct cred *old;
767 struct cred *new;
768 int retval;
769 kuid_t kuid;
770
771 kuid = make_kuid(ns, uid);
772 if (!uid_valid(kuid))
773 return -EINVAL;
774
775 new = prepare_creds();
776 if (!new)
777 return -ENOMEM;
778 old = current_cred();
779
780 retval = -EPERM;
781 if (nsown_capable(CAP_SETUID)) {
782 new->suid = new->uid = kuid;
783 if (!uid_eq(kuid, old->uid)) {
784 retval = set_user(new);
785 if (retval < 0)
786 goto error;
787 }
788 } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
789 goto error;
790 }
791
792 new->fsuid = new->euid = kuid;
793
794 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
795 if (retval < 0)
796 goto error;
797
798 return commit_creds(new);
799
800 error:
801 abort_creds(new);
802 return retval;
803 }
804
805
806 /*
807 * This function implements a generic ability to update ruid, euid,
808 * and suid. This allows you to implement the 4.4 compatible seteuid().
809 */
810 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
811 {
812 struct user_namespace *ns = current_user_ns();
813 const struct cred *old;
814 struct cred *new;
815 int retval;
816 kuid_t kruid, keuid, ksuid;
817
818 kruid = make_kuid(ns, ruid);
819 keuid = make_kuid(ns, euid);
820 ksuid = make_kuid(ns, suid);
821
822 if ((ruid != (uid_t) -1) && !uid_valid(kruid))
823 return -EINVAL;
824
825 if ((euid != (uid_t) -1) && !uid_valid(keuid))
826 return -EINVAL;
827
828 if ((suid != (uid_t) -1) && !uid_valid(ksuid))
829 return -EINVAL;
830
831 new = prepare_creds();
832 if (!new)
833 return -ENOMEM;
834
835 old = current_cred();
836
837 retval = -EPERM;
838 if (!nsown_capable(CAP_SETUID)) {
839 if (ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) &&
840 !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
841 goto error;
842 if (euid != (uid_t) -1 && !uid_eq(keuid, old->uid) &&
843 !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
844 goto error;
845 if (suid != (uid_t) -1 && !uid_eq(ksuid, old->uid) &&
846 !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
847 goto error;
848 }
849
850 if (ruid != (uid_t) -1) {
851 new->uid = kruid;
852 if (!uid_eq(kruid, old->uid)) {
853 retval = set_user(new);
854 if (retval < 0)
855 goto error;
856 }
857 }
858 if (euid != (uid_t) -1)
859 new->euid = keuid;
860 if (suid != (uid_t) -1)
861 new->suid = ksuid;
862 new->fsuid = new->euid;
863
864 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
865 if (retval < 0)
866 goto error;
867
868 return commit_creds(new);
869
870 error:
871 abort_creds(new);
872 return retval;
873 }
874
875 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
876 {
877 const struct cred *cred = current_cred();
878 int retval;
879 uid_t ruid, euid, suid;
880
881 ruid = from_kuid_munged(cred->user_ns, cred->uid);
882 euid = from_kuid_munged(cred->user_ns, cred->euid);
883 suid = from_kuid_munged(cred->user_ns, cred->suid);
884
885 if (!(retval = put_user(ruid, ruidp)) &&
886 !(retval = put_user(euid, euidp)))
887 retval = put_user(suid, suidp);
888
889 return retval;
890 }
891
892 /*
893 * Same as above, but for rgid, egid, sgid.
894 */
895 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
896 {
897 struct user_namespace *ns = current_user_ns();
898 const struct cred *old;
899 struct cred *new;
900 int retval;
901 kgid_t krgid, kegid, ksgid;
902
903 krgid = make_kgid(ns, rgid);
904 kegid = make_kgid(ns, egid);
905 ksgid = make_kgid(ns, sgid);
906
907 if ((rgid != (gid_t) -1) && !gid_valid(krgid))
908 return -EINVAL;
909 if ((egid != (gid_t) -1) && !gid_valid(kegid))
910 return -EINVAL;
911 if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
912 return -EINVAL;
913
914 new = prepare_creds();
915 if (!new)
916 return -ENOMEM;
917 old = current_cred();
918
919 retval = -EPERM;
920 if (!nsown_capable(CAP_SETGID)) {
921 if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
922 !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
923 goto error;
924 if (egid != (gid_t) -1 && !gid_eq(kegid, old->gid) &&
925 !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
926 goto error;
927 if (sgid != (gid_t) -1 && !gid_eq(ksgid, old->gid) &&
928 !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
929 goto error;
930 }
931
932 if (rgid != (gid_t) -1)
933 new->gid = krgid;
934 if (egid != (gid_t) -1)
935 new->egid = kegid;
936 if (sgid != (gid_t) -1)
937 new->sgid = ksgid;
938 new->fsgid = new->egid;
939
940 return commit_creds(new);
941
942 error:
943 abort_creds(new);
944 return retval;
945 }
946
947 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
948 {
949 const struct cred *cred = current_cred();
950 int retval;
951 gid_t rgid, egid, sgid;
952
953 rgid = from_kgid_munged(cred->user_ns, cred->gid);
954 egid = from_kgid_munged(cred->user_ns, cred->egid);
955 sgid = from_kgid_munged(cred->user_ns, cred->sgid);
956
957 if (!(retval = put_user(rgid, rgidp)) &&
958 !(retval = put_user(egid, egidp)))
959 retval = put_user(sgid, sgidp);
960
961 return retval;
962 }
963
964
965 /*
966 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
967 * is used for "access()" and for the NFS daemon (letting nfsd stay at
968 * whatever uid it wants to). It normally shadows "euid", except when
969 * explicitly set by setfsuid() or for access..
970 */
971 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
972 {
973 const struct cred *old;
974 struct cred *new;
975 uid_t old_fsuid;
976 kuid_t kuid;
977
978 old = current_cred();
979 old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
980
981 kuid = make_kuid(old->user_ns, uid);
982 if (!uid_valid(kuid))
983 return old_fsuid;
984
985 new = prepare_creds();
986 if (!new)
987 return old_fsuid;
988
989 if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) ||
990 uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
991 nsown_capable(CAP_SETUID)) {
992 if (!uid_eq(kuid, old->fsuid)) {
993 new->fsuid = kuid;
994 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
995 goto change_okay;
996 }
997 }
998
999 abort_creds(new);
1000 return old_fsuid;
1001
1002 change_okay:
1003 commit_creds(new);
1004 return old_fsuid;
1005 }
1006
1007 /*
1008 * Samma på svenska..
1009 */
1010 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
1011 {
1012 const struct cred *old;
1013 struct cred *new;
1014 gid_t old_fsgid;
1015 kgid_t kgid;
1016
1017 old = current_cred();
1018 old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
1019
1020 kgid = make_kgid(old->user_ns, gid);
1021 if (!gid_valid(kgid))
1022 return old_fsgid;
1023
1024 new = prepare_creds();
1025 if (!new)
1026 return old_fsgid;
1027
1028 if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
1029 gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
1030 nsown_capable(CAP_SETGID)) {
1031 if (!gid_eq(kgid, old->fsgid)) {
1032 new->fsgid = kgid;
1033 goto change_okay;
1034 }
1035 }
1036
1037 abort_creds(new);
1038 return old_fsgid;
1039
1040 change_okay:
1041 commit_creds(new);
1042 return old_fsgid;
1043 }
1044
1045 void do_sys_times(struct tms *tms)
1046 {
1047 cputime_t tgutime, tgstime, cutime, cstime;
1048
1049 spin_lock_irq(&current->sighand->siglock);
1050 thread_group_cputime_adjusted(current, &tgutime, &tgstime);
1051 cutime = current->signal->cutime;
1052 cstime = current->signal->cstime;
1053 spin_unlock_irq(&current->sighand->siglock);
1054 tms->tms_utime = cputime_to_clock_t(tgutime);
1055 tms->tms_stime = cputime_to_clock_t(tgstime);
1056 tms->tms_cutime = cputime_to_clock_t(cutime);
1057 tms->tms_cstime = cputime_to_clock_t(cstime);
1058 }
1059
1060 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
1061 {
1062 if (tbuf) {
1063 struct tms tmp;
1064
1065 do_sys_times(&tmp);
1066 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1067 return -EFAULT;
1068 }
1069 force_successful_syscall_return();
1070 return (long) jiffies_64_to_clock_t(get_jiffies_64());
1071 }
1072
1073 /*
1074 * This needs some heavy checking ...
1075 * I just haven't the stomach for it. I also don't fully
1076 * understand sessions/pgrp etc. Let somebody who does explain it.
1077 *
1078 * OK, I think I have the protection semantics right.... this is really
1079 * only important on a multi-user system anyway, to make sure one user
1080 * can't send a signal to a process owned by another. -TYT, 12/12/91
1081 *
1082 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1083 * LBT 04.03.94
1084 */
1085 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1086 {
1087 struct task_struct *p;
1088 struct task_struct *group_leader = current->group_leader;
1089 struct pid *pgrp;
1090 int err;
1091
1092 if (!pid)
1093 pid = task_pid_vnr(group_leader);
1094 if (!pgid)
1095 pgid = pid;
1096 if (pgid < 0)
1097 return -EINVAL;
1098 rcu_read_lock();
1099
1100 /* From this point forward we keep holding onto the tasklist lock
1101 * so that our parent does not change from under us. -DaveM
1102 */
1103 write_lock_irq(&tasklist_lock);
1104
1105 err = -ESRCH;
1106 p = find_task_by_vpid(pid);
1107 if (!p)
1108 goto out;
1109
1110 err = -EINVAL;
1111 if (!thread_group_leader(p))
1112 goto out;
1113
1114 if (same_thread_group(p->real_parent, group_leader)) {
1115 err = -EPERM;
1116 if (task_session(p) != task_session(group_leader))
1117 goto out;
1118 err = -EACCES;
1119 if (p->did_exec)
1120 goto out;
1121 } else {
1122 err = -ESRCH;
1123 if (p != group_leader)
1124 goto out;
1125 }
1126
1127 err = -EPERM;
1128 if (p->signal->leader)
1129 goto out;
1130
1131 pgrp = task_pid(p);
1132 if (pgid != pid) {
1133 struct task_struct *g;
1134
1135 pgrp = find_vpid(pgid);
1136 g = pid_task(pgrp, PIDTYPE_PGID);
1137 if (!g || task_session(g) != task_session(group_leader))
1138 goto out;
1139 }
1140
1141 err = security_task_setpgid(p, pgid);
1142 if (err)
1143 goto out;
1144
1145 if (task_pgrp(p) != pgrp)
1146 change_pid(p, PIDTYPE_PGID, pgrp);
1147
1148 err = 0;
1149 out:
1150 /* All paths lead to here, thus we are safe. -DaveM */
1151 write_unlock_irq(&tasklist_lock);
1152 rcu_read_unlock();
1153 return err;
1154 }
1155
1156 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1157 {
1158 struct task_struct *p;
1159 struct pid *grp;
1160 int retval;
1161
1162 rcu_read_lock();
1163 if (!pid)
1164 grp = task_pgrp(current);
1165 else {
1166 retval = -ESRCH;
1167 p = find_task_by_vpid(pid);
1168 if (!p)
1169 goto out;
1170 grp = task_pgrp(p);
1171 if (!grp)
1172 goto out;
1173
1174 retval = security_task_getpgid(p);
1175 if (retval)
1176 goto out;
1177 }
1178 retval = pid_vnr(grp);
1179 out:
1180 rcu_read_unlock();
1181 return retval;
1182 }
1183
1184 #ifdef __ARCH_WANT_SYS_GETPGRP
1185
1186 SYSCALL_DEFINE0(getpgrp)
1187 {
1188 return sys_getpgid(0);
1189 }
1190
1191 #endif
1192
1193 SYSCALL_DEFINE1(getsid, pid_t, pid)
1194 {
1195 struct task_struct *p;
1196 struct pid *sid;
1197 int retval;
1198
1199 rcu_read_lock();
1200 if (!pid)
1201 sid = task_session(current);
1202 else {
1203 retval = -ESRCH;
1204 p = find_task_by_vpid(pid);
1205 if (!p)
1206 goto out;
1207 sid = task_session(p);
1208 if (!sid)
1209 goto out;
1210
1211 retval = security_task_getsid(p);
1212 if (retval)
1213 goto out;
1214 }
1215 retval = pid_vnr(sid);
1216 out:
1217 rcu_read_unlock();
1218 return retval;
1219 }
1220
1221 SYSCALL_DEFINE0(setsid)
1222 {
1223 struct task_struct *group_leader = current->group_leader;
1224 struct pid *sid = task_pid(group_leader);
1225 pid_t session = pid_vnr(sid);
1226 int err = -EPERM;
1227
1228 write_lock_irq(&tasklist_lock);
1229 /* Fail if I am already a session leader */
1230 if (group_leader->signal->leader)
1231 goto out;
1232
1233 /* Fail if a process group id already exists that equals the
1234 * proposed session id.
1235 */
1236 if (pid_task(sid, PIDTYPE_PGID))
1237 goto out;
1238
1239 group_leader->signal->leader = 1;
1240 __set_special_pids(sid);
1241
1242 proc_clear_tty(group_leader);
1243
1244 err = session;
1245 out:
1246 write_unlock_irq(&tasklist_lock);
1247 if (err > 0) {
1248 proc_sid_connector(group_leader);
1249 sched_autogroup_create_attach(group_leader);
1250 }
1251 return err;
1252 }
1253
1254 DECLARE_RWSEM(uts_sem);
1255
1256 #ifdef COMPAT_UTS_MACHINE
1257 #define override_architecture(name) \
1258 (personality(current->personality) == PER_LINUX32 && \
1259 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1260 sizeof(COMPAT_UTS_MACHINE)))
1261 #else
1262 #define override_architecture(name) 0
1263 #endif
1264
1265 /*
1266 * Work around broken programs that cannot handle "Linux 3.0".
1267 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1268 */
1269 static int override_release(char __user *release, size_t len)
1270 {
1271 int ret = 0;
1272
1273 if (current->personality & UNAME26) {
1274 const char *rest = UTS_RELEASE;
1275 char buf[65] = { 0 };
1276 int ndots = 0;
1277 unsigned v;
1278 size_t copy;
1279
1280 while (*rest) {
1281 if (*rest == '.' && ++ndots >= 3)
1282 break;
1283 if (!isdigit(*rest) && *rest != '.')
1284 break;
1285 rest++;
1286 }
1287 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1288 copy = clamp_t(size_t, len, 1, sizeof(buf));
1289 copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
1290 ret = copy_to_user(release, buf, copy + 1);
1291 }
1292 return ret;
1293 }
1294
1295 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1296 {
1297 int errno = 0;
1298
1299 down_read(&uts_sem);
1300 if (copy_to_user(name, utsname(), sizeof *name))
1301 errno = -EFAULT;
1302 up_read(&uts_sem);
1303
1304 if (!errno && override_release(name->release, sizeof(name->release)))
1305 errno = -EFAULT;
1306 if (!errno && override_architecture(name))
1307 errno = -EFAULT;
1308 return errno;
1309 }
1310
1311 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1312 /*
1313 * Old cruft
1314 */
1315 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1316 {
1317 int error = 0;
1318
1319 if (!name)
1320 return -EFAULT;
1321
1322 down_read(&uts_sem);
1323 if (copy_to_user(name, utsname(), sizeof(*name)))
1324 error = -EFAULT;
1325 up_read(&uts_sem);
1326
1327 if (!error && override_release(name->release, sizeof(name->release)))
1328 error = -EFAULT;
1329 if (!error && override_architecture(name))
1330 error = -EFAULT;
1331 return error;
1332 }
1333
1334 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1335 {
1336 int error;
1337
1338 if (!name)
1339 return -EFAULT;
1340 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1341 return -EFAULT;
1342
1343 down_read(&uts_sem);
1344 error = __copy_to_user(&name->sysname, &utsname()->sysname,
1345 __OLD_UTS_LEN);
1346 error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1347 error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1348 __OLD_UTS_LEN);
1349 error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1350 error |= __copy_to_user(&name->release, &utsname()->release,
1351 __OLD_UTS_LEN);
1352 error |= __put_user(0, name->release + __OLD_UTS_LEN);
1353 error |= __copy_to_user(&name->version, &utsname()->version,
1354 __OLD_UTS_LEN);
1355 error |= __put_user(0, name->version + __OLD_UTS_LEN);
1356 error |= __copy_to_user(&name->machine, &utsname()->machine,
1357 __OLD_UTS_LEN);
1358 error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1359 up_read(&uts_sem);
1360
1361 if (!error && override_architecture(name))
1362 error = -EFAULT;
1363 if (!error && override_release(name->release, sizeof(name->release)))
1364 error = -EFAULT;
1365 return error ? -EFAULT : 0;
1366 }
1367 #endif
1368
1369 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1370 {
1371 int errno;
1372 char tmp[__NEW_UTS_LEN];
1373
1374 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1375 return -EPERM;
1376
1377 if (len < 0 || len > __NEW_UTS_LEN)
1378 return -EINVAL;
1379 down_write(&uts_sem);
1380 errno = -EFAULT;
1381 if (!copy_from_user(tmp, name, len)) {
1382 struct new_utsname *u = utsname();
1383
1384 memcpy(u->nodename, tmp, len);
1385 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1386 errno = 0;
1387 uts_proc_notify(UTS_PROC_HOSTNAME);
1388 }
1389 up_write(&uts_sem);
1390 return errno;
1391 }
1392
1393 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1394
1395 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1396 {
1397 int i, errno;
1398 struct new_utsname *u;
1399
1400 if (len < 0)
1401 return -EINVAL;
1402 down_read(&uts_sem);
1403 u = utsname();
1404 i = 1 + strlen(u->nodename);
1405 if (i > len)
1406 i = len;
1407 errno = 0;
1408 if (copy_to_user(name, u->nodename, i))
1409 errno = -EFAULT;
1410 up_read(&uts_sem);
1411 return errno;
1412 }
1413
1414 #endif
1415
1416 /*
1417 * Only setdomainname; getdomainname can be implemented by calling
1418 * uname()
1419 */
1420 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1421 {
1422 int errno;
1423 char tmp[__NEW_UTS_LEN];
1424
1425 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1426 return -EPERM;
1427 if (len < 0 || len > __NEW_UTS_LEN)
1428 return -EINVAL;
1429
1430 down_write(&uts_sem);
1431 errno = -EFAULT;
1432 if (!copy_from_user(tmp, name, len)) {
1433 struct new_utsname *u = utsname();
1434
1435 memcpy(u->domainname, tmp, len);
1436 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1437 errno = 0;
1438 uts_proc_notify(UTS_PROC_DOMAINNAME);
1439 }
1440 up_write(&uts_sem);
1441 return errno;
1442 }
1443
1444 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1445 {
1446 struct rlimit value;
1447 int ret;
1448
1449 ret = do_prlimit(current, resource, NULL, &value);
1450 if (!ret)
1451 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1452
1453 return ret;
1454 }
1455
1456 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1457
1458 /*
1459 * Back compatibility for getrlimit. Needed for some apps.
1460 */
1461
1462 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1463 struct rlimit __user *, rlim)
1464 {
1465 struct rlimit x;
1466 if (resource >= RLIM_NLIMITS)
1467 return -EINVAL;
1468
1469 task_lock(current->group_leader);
1470 x = current->signal->rlim[resource];
1471 task_unlock(current->group_leader);
1472 if (x.rlim_cur > 0x7FFFFFFF)
1473 x.rlim_cur = 0x7FFFFFFF;
1474 if (x.rlim_max > 0x7FFFFFFF)
1475 x.rlim_max = 0x7FFFFFFF;
1476 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1477 }
1478
1479 #endif
1480
1481 static inline bool rlim64_is_infinity(__u64 rlim64)
1482 {
1483 #if BITS_PER_LONG < 64
1484 return rlim64 >= ULONG_MAX;
1485 #else
1486 return rlim64 == RLIM64_INFINITY;
1487 #endif
1488 }
1489
1490 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1491 {
1492 if (rlim->rlim_cur == RLIM_INFINITY)
1493 rlim64->rlim_cur = RLIM64_INFINITY;
1494 else
1495 rlim64->rlim_cur = rlim->rlim_cur;
1496 if (rlim->rlim_max == RLIM_INFINITY)
1497 rlim64->rlim_max = RLIM64_INFINITY;
1498 else
1499 rlim64->rlim_max = rlim->rlim_max;
1500 }
1501
1502 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1503 {
1504 if (rlim64_is_infinity(rlim64->rlim_cur))
1505 rlim->rlim_cur = RLIM_INFINITY;
1506 else
1507 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1508 if (rlim64_is_infinity(rlim64->rlim_max))
1509 rlim->rlim_max = RLIM_INFINITY;
1510 else
1511 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1512 }
1513
1514 /* make sure you are allowed to change @tsk limits before calling this */
1515 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1516 struct rlimit *new_rlim, struct rlimit *old_rlim)
1517 {
1518 struct rlimit *rlim;
1519 int retval = 0;
1520
1521 if (resource >= RLIM_NLIMITS)
1522 return -EINVAL;
1523 if (new_rlim) {
1524 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1525 return -EINVAL;
1526 if (resource == RLIMIT_NOFILE &&
1527 new_rlim->rlim_max > sysctl_nr_open)
1528 return -EPERM;
1529 }
1530
1531 /* protect tsk->signal and tsk->sighand from disappearing */
1532 read_lock(&tasklist_lock);
1533 if (!tsk->sighand) {
1534 retval = -ESRCH;
1535 goto out;
1536 }
1537
1538 rlim = tsk->signal->rlim + resource;
1539 task_lock(tsk->group_leader);
1540 if (new_rlim) {
1541 /* Keep the capable check against init_user_ns until
1542 cgroups can contain all limits */
1543 if (new_rlim->rlim_max > rlim->rlim_max &&
1544 !capable(CAP_SYS_RESOURCE))
1545 retval = -EPERM;
1546 if (!retval)
1547 retval = security_task_setrlimit(tsk->group_leader,
1548 resource, new_rlim);
1549 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1550 /*
1551 * The caller is asking for an immediate RLIMIT_CPU
1552 * expiry. But we use the zero value to mean "it was
1553 * never set". So let's cheat and make it one second
1554 * instead
1555 */
1556 new_rlim->rlim_cur = 1;
1557 }
1558 }
1559 if (!retval) {
1560 if (old_rlim)
1561 *old_rlim = *rlim;
1562 if (new_rlim)
1563 *rlim = *new_rlim;
1564 }
1565 task_unlock(tsk->group_leader);
1566
1567 /*
1568 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1569 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1570 * very long-standing error, and fixing it now risks breakage of
1571 * applications, so we live with it
1572 */
1573 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1574 new_rlim->rlim_cur != RLIM_INFINITY)
1575 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1576 out:
1577 read_unlock(&tasklist_lock);
1578 return retval;
1579 }
1580
1581 /* rcu lock must be held */
1582 static int check_prlimit_permission(struct task_struct *task)
1583 {
1584 const struct cred *cred = current_cred(), *tcred;
1585
1586 if (current == task)
1587 return 0;
1588
1589 tcred = __task_cred(task);
1590 if (uid_eq(cred->uid, tcred->euid) &&
1591 uid_eq(cred->uid, tcred->suid) &&
1592 uid_eq(cred->uid, tcred->uid) &&
1593 gid_eq(cred->gid, tcred->egid) &&
1594 gid_eq(cred->gid, tcred->sgid) &&
1595 gid_eq(cred->gid, tcred->gid))
1596 return 0;
1597 if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1598 return 0;
1599
1600 return -EPERM;
1601 }
1602
1603 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1604 const struct rlimit64 __user *, new_rlim,
1605 struct rlimit64 __user *, old_rlim)
1606 {
1607 struct rlimit64 old64, new64;
1608 struct rlimit old, new;
1609 struct task_struct *tsk;
1610 int ret;
1611
1612 if (new_rlim) {
1613 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1614 return -EFAULT;
1615 rlim64_to_rlim(&new64, &new);
1616 }
1617
1618 rcu_read_lock();
1619 tsk = pid ? find_task_by_vpid(pid) : current;
1620 if (!tsk) {
1621 rcu_read_unlock();
1622 return -ESRCH;
1623 }
1624 ret = check_prlimit_permission(tsk);
1625 if (ret) {
1626 rcu_read_unlock();
1627 return ret;
1628 }
1629 get_task_struct(tsk);
1630 rcu_read_unlock();
1631
1632 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1633 old_rlim ? &old : NULL);
1634
1635 if (!ret && old_rlim) {
1636 rlim_to_rlim64(&old, &old64);
1637 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1638 ret = -EFAULT;
1639 }
1640
1641 put_task_struct(tsk);
1642 return ret;
1643 }
1644
1645 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1646 {
1647 struct rlimit new_rlim;
1648
1649 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1650 return -EFAULT;
1651 return do_prlimit(current, resource, &new_rlim, NULL);
1652 }
1653
1654 /*
1655 * It would make sense to put struct rusage in the task_struct,
1656 * except that would make the task_struct be *really big*. After
1657 * task_struct gets moved into malloc'ed memory, it would
1658 * make sense to do this. It will make moving the rest of the information
1659 * a lot simpler! (Which we're not doing right now because we're not
1660 * measuring them yet).
1661 *
1662 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1663 * races with threads incrementing their own counters. But since word
1664 * reads are atomic, we either get new values or old values and we don't
1665 * care which for the sums. We always take the siglock to protect reading
1666 * the c* fields from p->signal from races with exit.c updating those
1667 * fields when reaping, so a sample either gets all the additions of a
1668 * given child after it's reaped, or none so this sample is before reaping.
1669 *
1670 * Locking:
1671 * We need to take the siglock for CHILDEREN, SELF and BOTH
1672 * for the cases current multithreaded, non-current single threaded
1673 * non-current multithreaded. Thread traversal is now safe with
1674 * the siglock held.
1675 * Strictly speaking, we donot need to take the siglock if we are current and
1676 * single threaded, as no one else can take our signal_struct away, no one
1677 * else can reap the children to update signal->c* counters, and no one else
1678 * can race with the signal-> fields. If we do not take any lock, the
1679 * signal-> fields could be read out of order while another thread was just
1680 * exiting. So we should place a read memory barrier when we avoid the lock.
1681 * On the writer side, write memory barrier is implied in __exit_signal
1682 * as __exit_signal releases the siglock spinlock after updating the signal->
1683 * fields. But we don't do this yet to keep things simple.
1684 *
1685 */
1686
1687 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1688 {
1689 r->ru_nvcsw += t->nvcsw;
1690 r->ru_nivcsw += t->nivcsw;
1691 r->ru_minflt += t->min_flt;
1692 r->ru_majflt += t->maj_flt;
1693 r->ru_inblock += task_io_get_inblock(t);
1694 r->ru_oublock += task_io_get_oublock(t);
1695 }
1696
1697 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1698 {
1699 struct task_struct *t;
1700 unsigned long flags;
1701 cputime_t tgutime, tgstime, utime, stime;
1702 unsigned long maxrss = 0;
1703
1704 memset((char *) r, 0, sizeof *r);
1705 utime = stime = 0;
1706
1707 if (who == RUSAGE_THREAD) {
1708 task_cputime_adjusted(current, &utime, &stime);
1709 accumulate_thread_rusage(p, r);
1710 maxrss = p->signal->maxrss;
1711 goto out;
1712 }
1713
1714 if (!lock_task_sighand(p, &flags))
1715 return;
1716
1717 switch (who) {
1718 case RUSAGE_BOTH:
1719 case RUSAGE_CHILDREN:
1720 utime = p->signal->cutime;
1721 stime = p->signal->cstime;
1722 r->ru_nvcsw = p->signal->cnvcsw;
1723 r->ru_nivcsw = p->signal->cnivcsw;
1724 r->ru_minflt = p->signal->cmin_flt;
1725 r->ru_majflt = p->signal->cmaj_flt;
1726 r->ru_inblock = p->signal->cinblock;
1727 r->ru_oublock = p->signal->coublock;
1728 maxrss = p->signal->cmaxrss;
1729
1730 if (who == RUSAGE_CHILDREN)
1731 break;
1732
1733 case RUSAGE_SELF:
1734 thread_group_cputime_adjusted(p, &tgutime, &tgstime);
1735 utime += tgutime;
1736 stime += tgstime;
1737 r->ru_nvcsw += p->signal->nvcsw;
1738 r->ru_nivcsw += p->signal->nivcsw;
1739 r->ru_minflt += p->signal->min_flt;
1740 r->ru_majflt += p->signal->maj_flt;
1741 r->ru_inblock += p->signal->inblock;
1742 r->ru_oublock += p->signal->oublock;
1743 if (maxrss < p->signal->maxrss)
1744 maxrss = p->signal->maxrss;
1745 t = p;
1746 do {
1747 accumulate_thread_rusage(t, r);
1748 t = next_thread(t);
1749 } while (t != p);
1750 break;
1751
1752 default:
1753 BUG();
1754 }
1755 unlock_task_sighand(p, &flags);
1756
1757 out:
1758 cputime_to_timeval(utime, &r->ru_utime);
1759 cputime_to_timeval(stime, &r->ru_stime);
1760
1761 if (who != RUSAGE_CHILDREN) {
1762 struct mm_struct *mm = get_task_mm(p);
1763 if (mm) {
1764 setmax_mm_hiwater_rss(&maxrss, mm);
1765 mmput(mm);
1766 }
1767 }
1768 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1769 }
1770
1771 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1772 {
1773 struct rusage r;
1774 k_getrusage(p, who, &r);
1775 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1776 }
1777
1778 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1779 {
1780 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1781 who != RUSAGE_THREAD)
1782 return -EINVAL;
1783 return getrusage(current, who, ru);
1784 }
1785
1786 SYSCALL_DEFINE1(umask, int, mask)
1787 {
1788 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1789 return mask;
1790 }
1791
1792 #ifdef CONFIG_CHECKPOINT_RESTORE
1793 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1794 {
1795 struct fd exe;
1796 struct dentry *dentry;
1797 int err;
1798
1799 exe = fdget(fd);
1800 if (!exe.file)
1801 return -EBADF;
1802
1803 dentry = exe.file->f_path.dentry;
1804
1805 /*
1806 * Because the original mm->exe_file points to executable file, make
1807 * sure that this one is executable as well, to avoid breaking an
1808 * overall picture.
1809 */
1810 err = -EACCES;
1811 if (!S_ISREG(dentry->d_inode->i_mode) ||
1812 exe.file->f_path.mnt->mnt_flags & MNT_NOEXEC)
1813 goto exit;
1814
1815 err = inode_permission(dentry->d_inode, MAY_EXEC);
1816 if (err)
1817 goto exit;
1818
1819 down_write(&mm->mmap_sem);
1820
1821 /*
1822 * Forbid mm->exe_file change if old file still mapped.
1823 */
1824 err = -EBUSY;
1825 if (mm->exe_file) {
1826 struct vm_area_struct *vma;
1827
1828 for (vma = mm->mmap; vma; vma = vma->vm_next)
1829 if (vma->vm_file &&
1830 path_equal(&vma->vm_file->f_path,
1831 &mm->exe_file->f_path))
1832 goto exit_unlock;
1833 }
1834
1835 /*
1836 * The symlink can be changed only once, just to disallow arbitrary
1837 * transitions malicious software might bring in. This means one
1838 * could make a snapshot over all processes running and monitor
1839 * /proc/pid/exe changes to notice unusual activity if needed.
1840 */
1841 err = -EPERM;
1842 if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
1843 goto exit_unlock;
1844
1845 err = 0;
1846 set_mm_exe_file(mm, exe.file); /* this grabs a reference to exe.file */
1847 exit_unlock:
1848 up_write(&mm->mmap_sem);
1849
1850 exit:
1851 fdput(exe);
1852 return err;
1853 }
1854
1855 static int prctl_set_mm(int opt, unsigned long addr,
1856 unsigned long arg4, unsigned long arg5)
1857 {
1858 unsigned long rlim = rlimit(RLIMIT_DATA);
1859 struct mm_struct *mm = current->mm;
1860 struct vm_area_struct *vma;
1861 int error;
1862
1863 if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
1864 return -EINVAL;
1865
1866 if (!capable(CAP_SYS_RESOURCE))
1867 return -EPERM;
1868
1869 if (opt == PR_SET_MM_EXE_FILE)
1870 return prctl_set_mm_exe_file(mm, (unsigned int)addr);
1871
1872 if (addr >= TASK_SIZE || addr < mmap_min_addr)
1873 return -EINVAL;
1874
1875 error = -EINVAL;
1876
1877 down_read(&mm->mmap_sem);
1878 vma = find_vma(mm, addr);
1879
1880 switch (opt) {
1881 case PR_SET_MM_START_CODE:
1882 mm->start_code = addr;
1883 break;
1884 case PR_SET_MM_END_CODE:
1885 mm->end_code = addr;
1886 break;
1887 case PR_SET_MM_START_DATA:
1888 mm->start_data = addr;
1889 break;
1890 case PR_SET_MM_END_DATA:
1891 mm->end_data = addr;
1892 break;
1893
1894 case PR_SET_MM_START_BRK:
1895 if (addr <= mm->end_data)
1896 goto out;
1897
1898 if (rlim < RLIM_INFINITY &&
1899 (mm->brk - addr) +
1900 (mm->end_data - mm->start_data) > rlim)
1901 goto out;
1902
1903 mm->start_brk = addr;
1904 break;
1905
1906 case PR_SET_MM_BRK:
1907 if (addr <= mm->end_data)
1908 goto out;
1909
1910 if (rlim < RLIM_INFINITY &&
1911 (addr - mm->start_brk) +
1912 (mm->end_data - mm->start_data) > rlim)
1913 goto out;
1914
1915 mm->brk = addr;
1916 break;
1917
1918 /*
1919 * If command line arguments and environment
1920 * are placed somewhere else on stack, we can
1921 * set them up here, ARG_START/END to setup
1922 * command line argumets and ENV_START/END
1923 * for environment.
1924 */
1925 case PR_SET_MM_START_STACK:
1926 case PR_SET_MM_ARG_START:
1927 case PR_SET_MM_ARG_END:
1928 case PR_SET_MM_ENV_START:
1929 case PR_SET_MM_ENV_END:
1930 if (!vma) {
1931 error = -EFAULT;
1932 goto out;
1933 }
1934 if (opt == PR_SET_MM_START_STACK)
1935 mm->start_stack = addr;
1936 else if (opt == PR_SET_MM_ARG_START)
1937 mm->arg_start = addr;
1938 else if (opt == PR_SET_MM_ARG_END)
1939 mm->arg_end = addr;
1940 else if (opt == PR_SET_MM_ENV_START)
1941 mm->env_start = addr;
1942 else if (opt == PR_SET_MM_ENV_END)
1943 mm->env_end = addr;
1944 break;
1945
1946 /*
1947 * This doesn't move auxiliary vector itself
1948 * since it's pinned to mm_struct, but allow
1949 * to fill vector with new values. It's up
1950 * to a caller to provide sane values here
1951 * otherwise user space tools which use this
1952 * vector might be unhappy.
1953 */
1954 case PR_SET_MM_AUXV: {
1955 unsigned long user_auxv[AT_VECTOR_SIZE];
1956
1957 if (arg4 > sizeof(user_auxv))
1958 goto out;
1959 up_read(&mm->mmap_sem);
1960
1961 if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
1962 return -EFAULT;
1963
1964 /* Make sure the last entry is always AT_NULL */
1965 user_auxv[AT_VECTOR_SIZE - 2] = 0;
1966 user_auxv[AT_VECTOR_SIZE - 1] = 0;
1967
1968 BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1969
1970 task_lock(current);
1971 memcpy(mm->saved_auxv, user_auxv, arg4);
1972 task_unlock(current);
1973
1974 return 0;
1975 }
1976 default:
1977 goto out;
1978 }
1979
1980 error = 0;
1981 out:
1982 up_read(&mm->mmap_sem);
1983 return error;
1984 }
1985
1986 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1987 {
1988 return put_user(me->clear_child_tid, tid_addr);
1989 }
1990
1991 #else /* CONFIG_CHECKPOINT_RESTORE */
1992 static int prctl_set_mm(int opt, unsigned long addr,
1993 unsigned long arg4, unsigned long arg5)
1994 {
1995 return -EINVAL;
1996 }
1997 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1998 {
1999 return -EINVAL;
2000 }
2001 #endif
2002
2003 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2004 unsigned long, arg4, unsigned long, arg5)
2005 {
2006 struct task_struct *me = current;
2007 unsigned char comm[sizeof(me->comm)];
2008 long error;
2009
2010 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2011 if (error != -ENOSYS)
2012 return error;
2013
2014 error = 0;
2015 switch (option) {
2016 case PR_SET_PDEATHSIG:
2017 if (!valid_signal(arg2)) {
2018 error = -EINVAL;
2019 break;
2020 }
2021 me->pdeath_signal = arg2;
2022 break;
2023 case PR_GET_PDEATHSIG:
2024 error = put_user(me->pdeath_signal, (int __user *)arg2);
2025 break;
2026 case PR_GET_DUMPABLE:
2027 error = get_dumpable(me->mm);
2028 break;
2029 case PR_SET_DUMPABLE:
2030 if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
2031 error = -EINVAL;
2032 break;
2033 }
2034 set_dumpable(me->mm, arg2);
2035 break;
2036
2037 case PR_SET_UNALIGN:
2038 error = SET_UNALIGN_CTL(me, arg2);
2039 break;
2040 case PR_GET_UNALIGN:
2041 error = GET_UNALIGN_CTL(me, arg2);
2042 break;
2043 case PR_SET_FPEMU:
2044 error = SET_FPEMU_CTL(me, arg2);
2045 break;
2046 case PR_GET_FPEMU:
2047 error = GET_FPEMU_CTL(me, arg2);
2048 break;
2049 case PR_SET_FPEXC:
2050 error = SET_FPEXC_CTL(me, arg2);
2051 break;
2052 case PR_GET_FPEXC:
2053 error = GET_FPEXC_CTL(me, arg2);
2054 break;
2055 case PR_GET_TIMING:
2056 error = PR_TIMING_STATISTICAL;
2057 break;
2058 case PR_SET_TIMING:
2059 if (arg2 != PR_TIMING_STATISTICAL)
2060 error = -EINVAL;
2061 break;
2062 case PR_SET_NAME:
2063 comm[sizeof(me->comm) - 1] = 0;
2064 if (strncpy_from_user(comm, (char __user *)arg2,
2065 sizeof(me->comm) - 1) < 0)
2066 return -EFAULT;
2067 set_task_comm(me, comm);
2068 proc_comm_connector(me);
2069 break;
2070 case PR_GET_NAME:
2071 get_task_comm(comm, me);
2072 if (copy_to_user((char __user *)arg2, comm, sizeof(comm)))
2073 return -EFAULT;
2074 break;
2075 case PR_GET_ENDIAN:
2076 error = GET_ENDIAN(me, arg2);
2077 break;
2078 case PR_SET_ENDIAN:
2079 error = SET_ENDIAN(me, arg2);
2080 break;
2081 case PR_GET_SECCOMP:
2082 error = prctl_get_seccomp();
2083 break;
2084 case PR_SET_SECCOMP:
2085 error = prctl_set_seccomp(arg2, (char __user *)arg3);
2086 break;
2087 case PR_GET_TSC:
2088 error = GET_TSC_CTL(arg2);
2089 break;
2090 case PR_SET_TSC:
2091 error = SET_TSC_CTL(arg2);
2092 break;
2093 case PR_TASK_PERF_EVENTS_DISABLE:
2094 error = perf_event_task_disable();
2095 break;
2096 case PR_TASK_PERF_EVENTS_ENABLE:
2097 error = perf_event_task_enable();
2098 break;
2099 case PR_GET_TIMERSLACK:
2100 error = current->timer_slack_ns;
2101 break;
2102 case PR_SET_TIMERSLACK:
2103 if (arg2 <= 0)
2104 current->timer_slack_ns =
2105 current->default_timer_slack_ns;
2106 else
2107 current->timer_slack_ns = arg2;
2108 break;
2109 case PR_MCE_KILL:
2110 if (arg4 | arg5)
2111 return -EINVAL;
2112 switch (arg2) {
2113 case PR_MCE_KILL_CLEAR:
2114 if (arg3 != 0)
2115 return -EINVAL;
2116 current->flags &= ~PF_MCE_PROCESS;
2117 break;
2118 case PR_MCE_KILL_SET:
2119 current->flags |= PF_MCE_PROCESS;
2120 if (arg3 == PR_MCE_KILL_EARLY)
2121 current->flags |= PF_MCE_EARLY;
2122 else if (arg3 == PR_MCE_KILL_LATE)
2123 current->flags &= ~PF_MCE_EARLY;
2124 else if (arg3 == PR_MCE_KILL_DEFAULT)
2125 current->flags &=
2126 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
2127 else
2128 return -EINVAL;
2129 break;
2130 default:
2131 return -EINVAL;
2132 }
2133 break;
2134 case PR_MCE_KILL_GET:
2135 if (arg2 | arg3 | arg4 | arg5)
2136 return -EINVAL;
2137 if (current->flags & PF_MCE_PROCESS)
2138 error = (current->flags & PF_MCE_EARLY) ?
2139 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2140 else
2141 error = PR_MCE_KILL_DEFAULT;
2142 break;
2143 case PR_SET_MM:
2144 error = prctl_set_mm(arg2, arg3, arg4, arg5);
2145 break;
2146 case PR_GET_TID_ADDRESS:
2147 error = prctl_get_tid_address(me, (int __user **)arg2);
2148 break;
2149 case PR_SET_CHILD_SUBREAPER:
2150 me->signal->is_child_subreaper = !!arg2;
2151 break;
2152 case PR_GET_CHILD_SUBREAPER:
2153 error = put_user(me->signal->is_child_subreaper,
2154 (int __user *)arg2);
2155 break;
2156 case PR_SET_NO_NEW_PRIVS:
2157 if (arg2 != 1 || arg3 || arg4 || arg5)
2158 return -EINVAL;
2159
2160 current->no_new_privs = 1;
2161 break;
2162 case PR_GET_NO_NEW_PRIVS:
2163 if (arg2 || arg3 || arg4 || arg5)
2164 return -EINVAL;
2165 return current->no_new_privs ? 1 : 0;
2166 default:
2167 error = -EINVAL;
2168 break;
2169 }
2170 return error;
2171 }
2172
2173 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2174 struct getcpu_cache __user *, unused)
2175 {
2176 int err = 0;
2177 int cpu = raw_smp_processor_id();
2178 if (cpup)
2179 err |= put_user(cpu, cpup);
2180 if (nodep)
2181 err |= put_user(cpu_to_node(cpu), nodep);
2182 return err ? -EFAULT : 0;
2183 }
2184
2185 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
2186
2187 static void argv_cleanup(struct subprocess_info *info)
2188 {
2189 argv_free(info->argv);
2190 }
2191
2192 static int __orderly_poweroff(void)
2193 {
2194 int argc;
2195 char **argv;
2196 static char *envp[] = {
2197 "HOME=/",
2198 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2199 NULL
2200 };
2201 int ret;
2202
2203 argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
2204 if (argv == NULL) {
2205 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2206 __func__, poweroff_cmd);
2207 return -ENOMEM;
2208 }
2209
2210 ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_WAIT_EXEC,
2211 NULL, argv_cleanup, NULL);
2212 if (ret == -ENOMEM)
2213 argv_free(argv);
2214
2215 return ret;
2216 }
2217
2218 /**
2219 * orderly_poweroff - Trigger an orderly system poweroff
2220 * @force: force poweroff if command execution fails
2221 *
2222 * This may be called from any context to trigger a system shutdown.
2223 * If the orderly shutdown fails, it will force an immediate shutdown.
2224 */
2225 int orderly_poweroff(bool force)
2226 {
2227 int ret = __orderly_poweroff();
2228
2229 if (ret && force) {
2230 printk(KERN_WARNING "Failed to start orderly shutdown: "
2231 "forcing the issue\n");
2232
2233 /*
2234 * I guess this should try to kick off some daemon to sync and
2235 * poweroff asap. Or not even bother syncing if we're doing an
2236 * emergency shutdown?
2237 */
2238 emergency_sync();
2239 kernel_power_off();
2240 }
2241
2242 return ret;
2243 }
2244 EXPORT_SYMBOL_GPL(orderly_poweroff);
Linux kernel - Deliverables
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