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Merge git://www.linux-watchdog.org/linux-watchdog
[linux-2.6.git] / kernel / sys.c
blobba0ae8eea6fbc32fb159c6dbf8d9868bcbaa1452
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/gfp.h>
40 #include <linux/syscore_ops.h>
41 #include <linux/version.h>
42 #include <linux/ctype.h>
43
44 #include <linux/compat.h>
45 #include <linux/syscalls.h>
46 #include <linux/kprobes.h>
47 #include <linux/user_namespace.h>
48
49 #include <linux/kmsg_dump.h>
50 /* Move somewhere else to avoid recompiling? */
51 #include <generated/utsrelease.h>
52
53 #include <asm/uaccess.h>
54 #include <asm/io.h>
55 #include <asm/unistd.h>
56
57 #ifndef SET_UNALIGN_CTL
58 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
59 #endif
60 #ifndef GET_UNALIGN_CTL
61 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
62 #endif
63 #ifndef SET_FPEMU_CTL
64 # define SET_FPEMU_CTL(a,b) (-EINVAL)
65 #endif
66 #ifndef GET_FPEMU_CTL
67 # define GET_FPEMU_CTL(a,b) (-EINVAL)
68 #endif
69 #ifndef SET_FPEXC_CTL
70 # define SET_FPEXC_CTL(a,b) (-EINVAL)
71 #endif
72 #ifndef GET_FPEXC_CTL
73 # define GET_FPEXC_CTL(a,b) (-EINVAL)
74 #endif
75 #ifndef GET_ENDIAN
76 # define GET_ENDIAN(a,b) (-EINVAL)
77 #endif
78 #ifndef SET_ENDIAN
79 # define SET_ENDIAN(a,b) (-EINVAL)
80 #endif
81 #ifndef GET_TSC_CTL
82 # define GET_TSC_CTL(a) (-EINVAL)
83 #endif
84 #ifndef SET_TSC_CTL
85 # define SET_TSC_CTL(a) (-EINVAL)
86 #endif
87
88 /*
89 * this is where the system-wide overflow UID and GID are defined, for
90 * architectures that now have 32-bit UID/GID but didn't in the past
91 */
92
93 int overflowuid = DEFAULT_OVERFLOWUID;
94 int overflowgid = DEFAULT_OVERFLOWGID;
95
96 #ifdef CONFIG_UID16
97 EXPORT_SYMBOL(overflowuid);
98 EXPORT_SYMBOL(overflowgid);
99 #endif
100
101 /*
102 * the same as above, but for filesystems which can only store a 16-bit
103 * UID and GID. as such, this is needed on all architectures
104 */
105
106 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
107 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
108
109 EXPORT_SYMBOL(fs_overflowuid);
110 EXPORT_SYMBOL(fs_overflowgid);
111
112 /*
113 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
114 */
115
116 int C_A_D = 1;
117 struct pid *cad_pid;
118 EXPORT_SYMBOL(cad_pid);
119
120 /*
121 * If set, this is used for preparing the system to power off.
122 */
123
124 void (*pm_power_off_prepare)(void);
125
126 /*
127 * Returns true if current's euid is same as p's uid or euid,
128 * or has CAP_SYS_NICE to p's user_ns.
129 *
130 * Called with rcu_read_lock, creds are safe
131 */
132 static bool set_one_prio_perm(struct task_struct *p)
133 {
134 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
135
136 if (pcred->user->user_ns == cred->user->user_ns &&
137 (pcred->uid == cred->euid ||
138 pcred->euid == cred->euid))
139 return true;
140 if (ns_capable(pcred->user->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
181 if (which > PRIO_USER || which < PRIO_PROCESS)
182 goto out;
183
184 /* normalize: avoid signed division (rounding problems) */
185 error = -ESRCH;
186 if (niceval < -20)
187 niceval = -20;
188 if (niceval > 19)
189 niceval = 19;
190
191 rcu_read_lock();
192 read_lock(&tasklist_lock);
193 switch (which) {
194 case PRIO_PROCESS:
195 if (who)
196 p = find_task_by_vpid(who);
197 else
198 p = current;
199 if (p)
200 error = set_one_prio(p, niceval, error);
201 break;
202 case PRIO_PGRP:
203 if (who)
204 pgrp = find_vpid(who);
205 else
206 pgrp = task_pgrp(current);
207 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
208 error = set_one_prio(p, niceval, error);
209 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
210 break;
211 case PRIO_USER:
212 user = (struct user_struct *) cred->user;
213 if (!who)
214 who = cred->uid;
215 else if ((who != cred->uid) &&
216 !(user = find_user(who)))
217 goto out_unlock; /* No processes for this user */
218
219 do_each_thread(g, p) {
220 if (__task_cred(p)->uid == who)
221 error = set_one_prio(p, niceval, error);
222 } while_each_thread(g, p);
223 if (who != cred->uid)
224 free_uid(user); /* For find_user() */
225 break;
226 }
227 out_unlock:
228 read_unlock(&tasklist_lock);
229 rcu_read_unlock();
230 out:
231 return error;
232 }
233
234 /*
235 * Ugh. To avoid negative return values, "getpriority()" will
236 * not return the normal nice-value, but a negated value that
237 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
238 * to stay compatible.
239 */
240 SYSCALL_DEFINE2(getpriority, int, which, int, who)
241 {
242 struct task_struct *g, *p;
243 struct user_struct *user;
244 const struct cred *cred = current_cred();
245 long niceval, retval = -ESRCH;
246 struct pid *pgrp;
247
248 if (which > PRIO_USER || which < PRIO_PROCESS)
249 return -EINVAL;
250
251 rcu_read_lock();
252 read_lock(&tasklist_lock);
253 switch (which) {
254 case PRIO_PROCESS:
255 if (who)
256 p = find_task_by_vpid(who);
257 else
258 p = current;
259 if (p) {
260 niceval = 20 - task_nice(p);
261 if (niceval > retval)
262 retval = niceval;
263 }
264 break;
265 case PRIO_PGRP:
266 if (who)
267 pgrp = find_vpid(who);
268 else
269 pgrp = task_pgrp(current);
270 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
271 niceval = 20 - task_nice(p);
272 if (niceval > retval)
273 retval = niceval;
274 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
275 break;
276 case PRIO_USER:
277 user = (struct user_struct *) cred->user;
278 if (!who)
279 who = cred->uid;
280 else if ((who != cred->uid) &&
281 !(user = find_user(who)))
282 goto out_unlock; /* No processes for this user */
283
284 do_each_thread(g, p) {
285 if (__task_cred(p)->uid == who) {
286 niceval = 20 - task_nice(p);
287 if (niceval > retval)
288 retval = niceval;
289 }
290 } while_each_thread(g, p);
291 if (who != cred->uid)
292 free_uid(user); /* for find_user() */
293 break;
294 }
295 out_unlock:
296 read_unlock(&tasklist_lock);
297 rcu_read_unlock();
298
299 return retval;
300 }
301
302 /**
303 * emergency_restart - reboot the system
304 *
305 * Without shutting down any hardware or taking any locks
306 * reboot the system. This is called when we know we are in
307 * trouble so this is our best effort to reboot. This is
308 * safe to call in interrupt context.
309 */
310 void emergency_restart(void)
311 {
312 kmsg_dump(KMSG_DUMP_EMERG);
313 machine_emergency_restart();
314 }
315 EXPORT_SYMBOL_GPL(emergency_restart);
316
317 void kernel_restart_prepare(char *cmd)
318 {
319 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
320 system_state = SYSTEM_RESTART;
321 usermodehelper_disable();
322 device_shutdown();
323 syscore_shutdown();
324 }
325
326 /**
327 * register_reboot_notifier - Register function to be called at reboot time
328 * @nb: Info about notifier function to be called
329 *
330 * Registers a function with the list of functions
331 * to be called at reboot time.
332 *
333 * Currently always returns zero, as blocking_notifier_chain_register()
334 * always returns zero.
335 */
336 int register_reboot_notifier(struct notifier_block *nb)
337 {
338 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
339 }
340 EXPORT_SYMBOL(register_reboot_notifier);
341
342 /**
343 * unregister_reboot_notifier - Unregister previously registered reboot notifier
344 * @nb: Hook to be unregistered
345 *
346 * Unregisters a previously registered reboot
347 * notifier function.
348 *
349 * Returns zero on success, or %-ENOENT on failure.
350 */
351 int unregister_reboot_notifier(struct notifier_block *nb)
352 {
353 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
354 }
355 EXPORT_SYMBOL(unregister_reboot_notifier);
356
357 /**
358 * kernel_restart - reboot the system
359 * @cmd: pointer to buffer containing command to execute for restart
360 * or %NULL
361 *
362 * Shutdown everything and perform a clean reboot.
363 * This is not safe to call in interrupt context.
364 */
365 void kernel_restart(char *cmd)
366 {
367 kernel_restart_prepare(cmd);
368 if (!cmd)
369 printk(KERN_EMERG "Restarting system.\n");
370 else
371 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
372 kmsg_dump(KMSG_DUMP_RESTART);
373 machine_restart(cmd);
374 }
375 EXPORT_SYMBOL_GPL(kernel_restart);
376
377 static void kernel_shutdown_prepare(enum system_states state)
378 {
379 blocking_notifier_call_chain(&reboot_notifier_list,
380 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
381 system_state = state;
382 usermodehelper_disable();
383 device_shutdown();
384 }
385 /**
386 * kernel_halt - halt the system
387 *
388 * Shutdown everything and perform a clean system halt.
389 */
390 void kernel_halt(void)
391 {
392 kernel_shutdown_prepare(SYSTEM_HALT);
393 syscore_shutdown();
394 printk(KERN_EMERG "System halted.\n");
395 kmsg_dump(KMSG_DUMP_HALT);
396 machine_halt();
397 }
398
399 EXPORT_SYMBOL_GPL(kernel_halt);
400
401 /**
402 * kernel_power_off - power_off the system
403 *
404 * Shutdown everything and perform a clean system power_off.
405 */
406 void kernel_power_off(void)
407 {
408 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
409 if (pm_power_off_prepare)
410 pm_power_off_prepare();
411 disable_nonboot_cpus();
412 syscore_shutdown();
413 printk(KERN_EMERG "Power down.\n");
414 kmsg_dump(KMSG_DUMP_POWEROFF);
415 machine_power_off();
416 }
417 EXPORT_SYMBOL_GPL(kernel_power_off);
418
419 static DEFINE_MUTEX(reboot_mutex);
420
421 /*
422 * Reboot system call: for obvious reasons only root may call it,
423 * and even root needs to set up some magic numbers in the registers
424 * so that some mistake won't make this reboot the whole machine.
425 * You can also set the meaning of the ctrl-alt-del-key here.
426 *
427 * reboot doesn't sync: do that yourself before calling this.
428 */
429 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
430 void __user *, arg)
431 {
432 char buffer[256];
433 int ret = 0;
434
435 /* We only trust the superuser with rebooting the system. */
436 if (!capable(CAP_SYS_BOOT))
437 return -EPERM;
438
439 /* For safety, we require "magic" arguments. */
440 if (magic1 != LINUX_REBOOT_MAGIC1 ||
441 (magic2 != LINUX_REBOOT_MAGIC2 &&
442 magic2 != LINUX_REBOOT_MAGIC2A &&
443 magic2 != LINUX_REBOOT_MAGIC2B &&
444 magic2 != LINUX_REBOOT_MAGIC2C))
445 return -EINVAL;
446
447 /*
448 * If pid namespaces are enabled and the current task is in a child
449 * pid_namespace, the command is handled by reboot_pid_ns() which will
450 * call do_exit().
451 */
452 ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
453 if (ret)
454 return ret;
455
456 /* Instead of trying to make the power_off code look like
457 * halt when pm_power_off is not set do it the easy way.
458 */
459 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
460 cmd = LINUX_REBOOT_CMD_HALT;
461
462 mutex_lock(&reboot_mutex);
463 switch (cmd) {
464 case LINUX_REBOOT_CMD_RESTART:
465 kernel_restart(NULL);
466 break;
467
468 case LINUX_REBOOT_CMD_CAD_ON:
469 C_A_D = 1;
470 break;
471
472 case LINUX_REBOOT_CMD_CAD_OFF:
473 C_A_D = 0;
474 break;
475
476 case LINUX_REBOOT_CMD_HALT:
477 kernel_halt();
478 do_exit(0);
479 panic("cannot halt");
480
481 case LINUX_REBOOT_CMD_POWER_OFF:
482 kernel_power_off();
483 do_exit(0);
484 break;
485
486 case LINUX_REBOOT_CMD_RESTART2:
487 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
488 ret = -EFAULT;
489 break;
490 }
491 buffer[sizeof(buffer) - 1] = '\0';
492
493 kernel_restart(buffer);
494 break;
495
496 #ifdef CONFIG_KEXEC
497 case LINUX_REBOOT_CMD_KEXEC:
498 ret = kernel_kexec();
499 break;
500 #endif
501
502 #ifdef CONFIG_HIBERNATION
503 case LINUX_REBOOT_CMD_SW_SUSPEND:
504 ret = hibernate();
505 break;
506 #endif
507
508 default:
509 ret = -EINVAL;
510 break;
511 }
512 mutex_unlock(&reboot_mutex);
513 return ret;
514 }
515
516 static void deferred_cad(struct work_struct *dummy)
517 {
518 kernel_restart(NULL);
519 }
520
521 /*
522 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
523 * As it's called within an interrupt, it may NOT sync: the only choice
524 * is whether to reboot at once, or just ignore the ctrl-alt-del.
525 */
526 void ctrl_alt_del(void)
527 {
528 static DECLARE_WORK(cad_work, deferred_cad);
529
530 if (C_A_D)
531 schedule_work(&cad_work);
532 else
533 kill_cad_pid(SIGINT, 1);
534 }
535
536 /*
537 * Unprivileged users may change the real gid to the effective gid
538 * or vice versa. (BSD-style)
539 *
540 * If you set the real gid at all, or set the effective gid to a value not
541 * equal to the real gid, then the saved gid is set to the new effective gid.
542 *
543 * This makes it possible for a setgid program to completely drop its
544 * privileges, which is often a useful assertion to make when you are doing
545 * a security audit over a program.
546 *
547 * The general idea is that a program which uses just setregid() will be
548 * 100% compatible with BSD. A program which uses just setgid() will be
549 * 100% compatible with POSIX with saved IDs.
550 *
551 * SMP: There are not races, the GIDs are checked only by filesystem
552 * operations (as far as semantic preservation is concerned).
553 */
554 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
555 {
556 const struct cred *old;
557 struct cred *new;
558 int retval;
559
560 new = prepare_creds();
561 if (!new)
562 return -ENOMEM;
563 old = current_cred();
564
565 retval = -EPERM;
566 if (rgid != (gid_t) -1) {
567 if (old->gid == rgid ||
568 old->egid == rgid ||
569 nsown_capable(CAP_SETGID))
570 new->gid = rgid;
571 else
572 goto error;
573 }
574 if (egid != (gid_t) -1) {
575 if (old->gid == egid ||
576 old->egid == egid ||
577 old->sgid == egid ||
578 nsown_capable(CAP_SETGID))
579 new->egid = egid;
580 else
581 goto error;
582 }
583
584 if (rgid != (gid_t) -1 ||
585 (egid != (gid_t) -1 && egid != old->gid))
586 new->sgid = new->egid;
587 new->fsgid = new->egid;
588
589 return commit_creds(new);
590
591 error:
592 abort_creds(new);
593 return retval;
594 }
595
596 /*
597 * setgid() is implemented like SysV w/ SAVED_IDS
598 *
599 * SMP: Same implicit races as above.
600 */
601 SYSCALL_DEFINE1(setgid, gid_t, gid)
602 {
603 const struct cred *old;
604 struct cred *new;
605 int retval;
606
607 new = prepare_creds();
608 if (!new)
609 return -ENOMEM;
610 old = current_cred();
611
612 retval = -EPERM;
613 if (nsown_capable(CAP_SETGID))
614 new->gid = new->egid = new->sgid = new->fsgid = gid;
615 else if (gid == old->gid || gid == old->sgid)
616 new->egid = new->fsgid = gid;
617 else
618 goto error;
619
620 return commit_creds(new);
621
622 error:
623 abort_creds(new);
624 return retval;
625 }
626
627 /*
628 * change the user struct in a credentials set to match the new UID
629 */
630 static int set_user(struct cred *new)
631 {
632 struct user_struct *new_user;
633
634 new_user = alloc_uid(current_user_ns(), new->uid);
635 if (!new_user)
636 return -EAGAIN;
637
638 /*
639 * We don't fail in case of NPROC limit excess here because too many
640 * poorly written programs don't check set*uid() return code, assuming
641 * it never fails if called by root. We may still enforce NPROC limit
642 * for programs doing set*uid()+execve() by harmlessly deferring the
643 * failure to the execve() stage.
644 */
645 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
646 new_user != INIT_USER)
647 current->flags |= PF_NPROC_EXCEEDED;
648 else
649 current->flags &= ~PF_NPROC_EXCEEDED;
650
651 free_uid(new->user);
652 new->user = new_user;
653 return 0;
654 }
655
656 /*
657 * Unprivileged users may change the real uid to the effective uid
658 * or vice versa. (BSD-style)
659 *
660 * If you set the real uid at all, or set the effective uid to a value not
661 * equal to the real uid, then the saved uid is set to the new effective uid.
662 *
663 * This makes it possible for a setuid program to completely drop its
664 * privileges, which is often a useful assertion to make when you are doing
665 * a security audit over a program.
666 *
667 * The general idea is that a program which uses just setreuid() will be
668 * 100% compatible with BSD. A program which uses just setuid() will be
669 * 100% compatible with POSIX with saved IDs.
670 */
671 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
672 {
673 const struct cred *old;
674 struct cred *new;
675 int retval;
676
677 new = prepare_creds();
678 if (!new)
679 return -ENOMEM;
680 old = current_cred();
681
682 retval = -EPERM;
683 if (ruid != (uid_t) -1) {
684 new->uid = ruid;
685 if (old->uid != ruid &&
686 old->euid != ruid &&
687 !nsown_capable(CAP_SETUID))
688 goto error;
689 }
690
691 if (euid != (uid_t) -1) {
692 new->euid = euid;
693 if (old->uid != euid &&
694 old->euid != euid &&
695 old->suid != euid &&
696 !nsown_capable(CAP_SETUID))
697 goto error;
698 }
699
700 if (new->uid != old->uid) {
701 retval = set_user(new);
702 if (retval < 0)
703 goto error;
704 }
705 if (ruid != (uid_t) -1 ||
706 (euid != (uid_t) -1 && euid != old->uid))
707 new->suid = new->euid;
708 new->fsuid = new->euid;
709
710 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
711 if (retval < 0)
712 goto error;
713
714 return commit_creds(new);
715
716 error:
717 abort_creds(new);
718 return retval;
719 }
720
721 /*
722 * setuid() is implemented like SysV with SAVED_IDS
723 *
724 * Note that SAVED_ID's is deficient in that a setuid root program
725 * like sendmail, for example, cannot set its uid to be a normal
726 * user and then switch back, because if you're root, setuid() sets
727 * the saved uid too. If you don't like this, blame the bright people
728 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
729 * will allow a root program to temporarily drop privileges and be able to
730 * regain them by swapping the real and effective uid.
731 */
732 SYSCALL_DEFINE1(setuid, uid_t, uid)
733 {
734 const struct cred *old;
735 struct cred *new;
736 int retval;
737
738 new = prepare_creds();
739 if (!new)
740 return -ENOMEM;
741 old = current_cred();
742
743 retval = -EPERM;
744 if (nsown_capable(CAP_SETUID)) {
745 new->suid = new->uid = uid;
746 if (uid != old->uid) {
747 retval = set_user(new);
748 if (retval < 0)
749 goto error;
750 }
751 } else if (uid != old->uid && uid != new->suid) {
752 goto error;
753 }
754
755 new->fsuid = new->euid = uid;
756
757 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
758 if (retval < 0)
759 goto error;
760
761 return commit_creds(new);
762
763 error:
764 abort_creds(new);
765 return retval;
766 }
767
768
769 /*
770 * This function implements a generic ability to update ruid, euid,
771 * and suid. This allows you to implement the 4.4 compatible seteuid().
772 */
773 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
774 {
775 const struct cred *old;
776 struct cred *new;
777 int retval;
778
779 new = prepare_creds();
780 if (!new)
781 return -ENOMEM;
782
783 old = current_cred();
784
785 retval = -EPERM;
786 if (!nsown_capable(CAP_SETUID)) {
787 if (ruid != (uid_t) -1 && ruid != old->uid &&
788 ruid != old->euid && ruid != old->suid)
789 goto error;
790 if (euid != (uid_t) -1 && euid != old->uid &&
791 euid != old->euid && euid != old->suid)
792 goto error;
793 if (suid != (uid_t) -1 && suid != old->uid &&
794 suid != old->euid && suid != old->suid)
795 goto error;
796 }
797
798 if (ruid != (uid_t) -1) {
799 new->uid = ruid;
800 if (ruid != old->uid) {
801 retval = set_user(new);
802 if (retval < 0)
803 goto error;
804 }
805 }
806 if (euid != (uid_t) -1)
807 new->euid = euid;
808 if (suid != (uid_t) -1)
809 new->suid = suid;
810 new->fsuid = new->euid;
811
812 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
813 if (retval < 0)
814 goto error;
815
816 return commit_creds(new);
817
818 error:
819 abort_creds(new);
820 return retval;
821 }
822
823 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
824 {
825 const struct cred *cred = current_cred();
826 int retval;
827
828 if (!(retval = put_user(cred->uid, ruid)) &&
829 !(retval = put_user(cred->euid, euid)))
830 retval = put_user(cred->suid, suid);
831
832 return retval;
833 }
834
835 /*
836 * Same as above, but for rgid, egid, sgid.
837 */
838 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
839 {
840 const struct cred *old;
841 struct cred *new;
842 int retval;
843
844 new = prepare_creds();
845 if (!new)
846 return -ENOMEM;
847 old = current_cred();
848
849 retval = -EPERM;
850 if (!nsown_capable(CAP_SETGID)) {
851 if (rgid != (gid_t) -1 && rgid != old->gid &&
852 rgid != old->egid && rgid != old->sgid)
853 goto error;
854 if (egid != (gid_t) -1 && egid != old->gid &&
855 egid != old->egid && egid != old->sgid)
856 goto error;
857 if (sgid != (gid_t) -1 && sgid != old->gid &&
858 sgid != old->egid && sgid != old->sgid)
859 goto error;
860 }
861
862 if (rgid != (gid_t) -1)
863 new->gid = rgid;
864 if (egid != (gid_t) -1)
865 new->egid = egid;
866 if (sgid != (gid_t) -1)
867 new->sgid = sgid;
868 new->fsgid = new->egid;
869
870 return commit_creds(new);
871
872 error:
873 abort_creds(new);
874 return retval;
875 }
876
877 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
878 {
879 const struct cred *cred = current_cred();
880 int retval;
881
882 if (!(retval = put_user(cred->gid, rgid)) &&
883 !(retval = put_user(cred->egid, egid)))
884 retval = put_user(cred->sgid, sgid);
885
886 return retval;
887 }
888
889
890 /*
891 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
892 * is used for "access()" and for the NFS daemon (letting nfsd stay at
893 * whatever uid it wants to). It normally shadows "euid", except when
894 * explicitly set by setfsuid() or for access..
895 */
896 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
897 {
898 const struct cred *old;
899 struct cred *new;
900 uid_t old_fsuid;
901
902 new = prepare_creds();
903 if (!new)
904 return current_fsuid();
905 old = current_cred();
906 old_fsuid = old->fsuid;
907
908 if (uid == old->uid || uid == old->euid ||
909 uid == old->suid || uid == old->fsuid ||
910 nsown_capable(CAP_SETUID)) {
911 if (uid != old_fsuid) {
912 new->fsuid = uid;
913 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
914 goto change_okay;
915 }
916 }
917
918 abort_creds(new);
919 return old_fsuid;
920
921 change_okay:
922 commit_creds(new);
923 return old_fsuid;
924 }
925
926 /*
927 * Samma på svenska..
928 */
929 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
930 {
931 const struct cred *old;
932 struct cred *new;
933 gid_t old_fsgid;
934
935 new = prepare_creds();
936 if (!new)
937 return current_fsgid();
938 old = current_cred();
939 old_fsgid = old->fsgid;
940
941 if (gid == old->gid || gid == old->egid ||
942 gid == old->sgid || gid == old->fsgid ||
943 nsown_capable(CAP_SETGID)) {
944 if (gid != old_fsgid) {
945 new->fsgid = gid;
946 goto change_okay;
947 }
948 }
949
950 abort_creds(new);
951 return old_fsgid;
952
953 change_okay:
954 commit_creds(new);
955 return old_fsgid;
956 }
957
958 void do_sys_times(struct tms *tms)
959 {
960 cputime_t tgutime, tgstime, cutime, cstime;
961
962 spin_lock_irq(&current->sighand->siglock);
963 thread_group_times(current, &tgutime, &tgstime);
964 cutime = current->signal->cutime;
965 cstime = current->signal->cstime;
966 spin_unlock_irq(&current->sighand->siglock);
967 tms->tms_utime = cputime_to_clock_t(tgutime);
968 tms->tms_stime = cputime_to_clock_t(tgstime);
969 tms->tms_cutime = cputime_to_clock_t(cutime);
970 tms->tms_cstime = cputime_to_clock_t(cstime);
971 }
972
973 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
974 {
975 if (tbuf) {
976 struct tms tmp;
977
978 do_sys_times(&tmp);
979 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
980 return -EFAULT;
981 }
982 force_successful_syscall_return();
983 return (long) jiffies_64_to_clock_t(get_jiffies_64());
984 }
985
986 /*
987 * This needs some heavy checking ...
988 * I just haven't the stomach for it. I also don't fully
989 * understand sessions/pgrp etc. Let somebody who does explain it.
990 *
991 * OK, I think I have the protection semantics right.... this is really
992 * only important on a multi-user system anyway, to make sure one user
993 * can't send a signal to a process owned by another. -TYT, 12/12/91
994 *
995 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
996 * LBT 04.03.94
997 */
998 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
999 {
1000 struct task_struct *p;
1001 struct task_struct *group_leader = current->group_leader;
1002 struct pid *pgrp;
1003 int err;
1004
1005 if (!pid)
1006 pid = task_pid_vnr(group_leader);
1007 if (!pgid)
1008 pgid = pid;
1009 if (pgid < 0)
1010 return -EINVAL;
1011 rcu_read_lock();
1012
1013 /* From this point forward we keep holding onto the tasklist lock
1014 * so that our parent does not change from under us. -DaveM
1015 */
1016 write_lock_irq(&tasklist_lock);
1017
1018 err = -ESRCH;
1019 p = find_task_by_vpid(pid);
1020 if (!p)
1021 goto out;
1022
1023 err = -EINVAL;
1024 if (!thread_group_leader(p))
1025 goto out;
1026
1027 if (same_thread_group(p->real_parent, group_leader)) {
1028 err = -EPERM;
1029 if (task_session(p) != task_session(group_leader))
1030 goto out;
1031 err = -EACCES;
1032 if (p->did_exec)
1033 goto out;
1034 } else {
1035 err = -ESRCH;
1036 if (p != group_leader)
1037 goto out;
1038 }
1039
1040 err = -EPERM;
1041 if (p->signal->leader)
1042 goto out;
1043
1044 pgrp = task_pid(p);
1045 if (pgid != pid) {
1046 struct task_struct *g;
1047
1048 pgrp = find_vpid(pgid);
1049 g = pid_task(pgrp, PIDTYPE_PGID);
1050 if (!g || task_session(g) != task_session(group_leader))
1051 goto out;
1052 }
1053
1054 err = security_task_setpgid(p, pgid);
1055 if (err)
1056 goto out;
1057
1058 if (task_pgrp(p) != pgrp)
1059 change_pid(p, PIDTYPE_PGID, pgrp);
1060
1061 err = 0;
1062 out:
1063 /* All paths lead to here, thus we are safe. -DaveM */
1064 write_unlock_irq(&tasklist_lock);
1065 rcu_read_unlock();
1066 return err;
1067 }
1068
1069 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1070 {
1071 struct task_struct *p;
1072 struct pid *grp;
1073 int retval;
1074
1075 rcu_read_lock();
1076 if (!pid)
1077 grp = task_pgrp(current);
1078 else {
1079 retval = -ESRCH;
1080 p = find_task_by_vpid(pid);
1081 if (!p)
1082 goto out;
1083 grp = task_pgrp(p);
1084 if (!grp)
1085 goto out;
1086
1087 retval = security_task_getpgid(p);
1088 if (retval)
1089 goto out;
1090 }
1091 retval = pid_vnr(grp);
1092 out:
1093 rcu_read_unlock();
1094 return retval;
1095 }
1096
1097 #ifdef __ARCH_WANT_SYS_GETPGRP
1098
1099 SYSCALL_DEFINE0(getpgrp)
1100 {
1101 return sys_getpgid(0);
1102 }
1103
1104 #endif
1105
1106 SYSCALL_DEFINE1(getsid, pid_t, pid)
1107 {
1108 struct task_struct *p;
1109 struct pid *sid;
1110 int retval;
1111
1112 rcu_read_lock();
1113 if (!pid)
1114 sid = task_session(current);
1115 else {
1116 retval = -ESRCH;
1117 p = find_task_by_vpid(pid);
1118 if (!p)
1119 goto out;
1120 sid = task_session(p);
1121 if (!sid)
1122 goto out;
1123
1124 retval = security_task_getsid(p);
1125 if (retval)
1126 goto out;
1127 }
1128 retval = pid_vnr(sid);
1129 out:
1130 rcu_read_unlock();
1131 return retval;
1132 }
1133
1134 SYSCALL_DEFINE0(setsid)
1135 {
1136 struct task_struct *group_leader = current->group_leader;
1137 struct pid *sid = task_pid(group_leader);
1138 pid_t session = pid_vnr(sid);
1139 int err = -EPERM;
1140
1141 write_lock_irq(&tasklist_lock);
1142 /* Fail if I am already a session leader */
1143 if (group_leader->signal->leader)
1144 goto out;
1145
1146 /* Fail if a process group id already exists that equals the
1147 * proposed session id.
1148 */
1149 if (pid_task(sid, PIDTYPE_PGID))
1150 goto out;
1151
1152 group_leader->signal->leader = 1;
1153 __set_special_pids(sid);
1154
1155 proc_clear_tty(group_leader);
1156
1157 err = session;
1158 out:
1159 write_unlock_irq(&tasklist_lock);
1160 if (err > 0) {
1161 proc_sid_connector(group_leader);
1162 sched_autogroup_create_attach(group_leader);
1163 }
1164 return err;
1165 }
1166
1167 DECLARE_RWSEM(uts_sem);
1168
1169 #ifdef COMPAT_UTS_MACHINE
1170 #define override_architecture(name) \
1171 (personality(current->personality) == PER_LINUX32 && \
1172 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1173 sizeof(COMPAT_UTS_MACHINE)))
1174 #else
1175 #define override_architecture(name) 0
1176 #endif
1177
1178 /*
1179 * Work around broken programs that cannot handle "Linux 3.0".
1180 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1181 */
1182 static int override_release(char __user *release, int len)
1183 {
1184 int ret = 0;
1185 char buf[65];
1186
1187 if (current->personality & UNAME26) {
1188 char *rest = UTS_RELEASE;
1189 int ndots = 0;
1190 unsigned v;
1191
1192 while (*rest) {
1193 if (*rest == '.' && ++ndots >= 3)
1194 break;
1195 if (!isdigit(*rest) && *rest != '.')
1196 break;
1197 rest++;
1198 }
1199 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1200 snprintf(buf, len, "2.6.%u%s", v, rest);
1201 ret = copy_to_user(release, buf, len);
1202 }
1203 return ret;
1204 }
1205
1206 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1207 {
1208 int errno = 0;
1209
1210 down_read(&uts_sem);
1211 if (copy_to_user(name, utsname(), sizeof *name))
1212 errno = -EFAULT;
1213 up_read(&uts_sem);
1214
1215 if (!errno && override_release(name->release, sizeof(name->release)))
1216 errno = -EFAULT;
1217 if (!errno && override_architecture(name))
1218 errno = -EFAULT;
1219 return errno;
1220 }
1221
1222 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1223 /*
1224 * Old cruft
1225 */
1226 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1227 {
1228 int error = 0;
1229
1230 if (!name)
1231 return -EFAULT;
1232
1233 down_read(&uts_sem);
1234 if (copy_to_user(name, utsname(), sizeof(*name)))
1235 error = -EFAULT;
1236 up_read(&uts_sem);
1237
1238 if (!error && override_release(name->release, sizeof(name->release)))
1239 error = -EFAULT;
1240 if (!error && override_architecture(name))
1241 error = -EFAULT;
1242 return error;
1243 }
1244
1245 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1246 {
1247 int error;
1248
1249 if (!name)
1250 return -EFAULT;
1251 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1252 return -EFAULT;
1253
1254 down_read(&uts_sem);
1255 error = __copy_to_user(&name->sysname, &utsname()->sysname,
1256 __OLD_UTS_LEN);
1257 error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1258 error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1259 __OLD_UTS_LEN);
1260 error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1261 error |= __copy_to_user(&name->release, &utsname()->release,
1262 __OLD_UTS_LEN);
1263 error |= __put_user(0, name->release + __OLD_UTS_LEN);
1264 error |= __copy_to_user(&name->version, &utsname()->version,
1265 __OLD_UTS_LEN);
1266 error |= __put_user(0, name->version + __OLD_UTS_LEN);
1267 error |= __copy_to_user(&name->machine, &utsname()->machine,
1268 __OLD_UTS_LEN);
1269 error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1270 up_read(&uts_sem);
1271
1272 if (!error && override_architecture(name))
1273 error = -EFAULT;
1274 if (!error && override_release(name->release, sizeof(name->release)))
1275 error = -EFAULT;
1276 return error ? -EFAULT : 0;
1277 }
1278 #endif
1279
1280 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1281 {
1282 int errno;
1283 char tmp[__NEW_UTS_LEN];
1284
1285 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1286 return -EPERM;
1287
1288 if (len < 0 || len > __NEW_UTS_LEN)
1289 return -EINVAL;
1290 down_write(&uts_sem);
1291 errno = -EFAULT;
1292 if (!copy_from_user(tmp, name, len)) {
1293 struct new_utsname *u = utsname();
1294
1295 memcpy(u->nodename, tmp, len);
1296 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1297 errno = 0;
1298 }
1299 uts_proc_notify(UTS_PROC_HOSTNAME);
1300 up_write(&uts_sem);
1301 return errno;
1302 }
1303
1304 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1305
1306 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1307 {
1308 int i, errno;
1309 struct new_utsname *u;
1310
1311 if (len < 0)
1312 return -EINVAL;
1313 down_read(&uts_sem);
1314 u = utsname();
1315 i = 1 + strlen(u->nodename);
1316 if (i > len)
1317 i = len;
1318 errno = 0;
1319 if (copy_to_user(name, u->nodename, i))
1320 errno = -EFAULT;
1321 up_read(&uts_sem);
1322 return errno;
1323 }
1324
1325 #endif
1326
1327 /*
1328 * Only setdomainname; getdomainname can be implemented by calling
1329 * uname()
1330 */
1331 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1332 {
1333 int errno;
1334 char tmp[__NEW_UTS_LEN];
1335
1336 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1337 return -EPERM;
1338 if (len < 0 || len > __NEW_UTS_LEN)
1339 return -EINVAL;
1340
1341 down_write(&uts_sem);
1342 errno = -EFAULT;
1343 if (!copy_from_user(tmp, name, len)) {
1344 struct new_utsname *u = utsname();
1345
1346 memcpy(u->domainname, tmp, len);
1347 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1348 errno = 0;
1349 }
1350 uts_proc_notify(UTS_PROC_DOMAINNAME);
1351 up_write(&uts_sem);
1352 return errno;
1353 }
1354
1355 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1356 {
1357 struct rlimit value;
1358 int ret;
1359
1360 ret = do_prlimit(current, resource, NULL, &value);
1361 if (!ret)
1362 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1363
1364 return ret;
1365 }
1366
1367 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1368
1369 /*
1370 * Back compatibility for getrlimit. Needed for some apps.
1371 */
1372
1373 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1374 struct rlimit __user *, rlim)
1375 {
1376 struct rlimit x;
1377 if (resource >= RLIM_NLIMITS)
1378 return -EINVAL;
1379
1380 task_lock(current->group_leader);
1381 x = current->signal->rlim[resource];
1382 task_unlock(current->group_leader);
1383 if (x.rlim_cur > 0x7FFFFFFF)
1384 x.rlim_cur = 0x7FFFFFFF;
1385 if (x.rlim_max > 0x7FFFFFFF)
1386 x.rlim_max = 0x7FFFFFFF;
1387 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1388 }
1389
1390 #endif
1391
1392 static inline bool rlim64_is_infinity(__u64 rlim64)
1393 {
1394 #if BITS_PER_LONG < 64
1395 return rlim64 >= ULONG_MAX;
1396 #else
1397 return rlim64 == RLIM64_INFINITY;
1398 #endif
1399 }
1400
1401 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1402 {
1403 if (rlim->rlim_cur == RLIM_INFINITY)
1404 rlim64->rlim_cur = RLIM64_INFINITY;
1405 else
1406 rlim64->rlim_cur = rlim->rlim_cur;
1407 if (rlim->rlim_max == RLIM_INFINITY)
1408 rlim64->rlim_max = RLIM64_INFINITY;
1409 else
1410 rlim64->rlim_max = rlim->rlim_max;
1411 }
1412
1413 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1414 {
1415 if (rlim64_is_infinity(rlim64->rlim_cur))
1416 rlim->rlim_cur = RLIM_INFINITY;
1417 else
1418 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1419 if (rlim64_is_infinity(rlim64->rlim_max))
1420 rlim->rlim_max = RLIM_INFINITY;
1421 else
1422 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1423 }
1424
1425 /* make sure you are allowed to change @tsk limits before calling this */
1426 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1427 struct rlimit *new_rlim, struct rlimit *old_rlim)
1428 {
1429 struct rlimit *rlim;
1430 int retval = 0;
1431
1432 if (resource >= RLIM_NLIMITS)
1433 return -EINVAL;
1434 if (new_rlim) {
1435 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1436 return -EINVAL;
1437 if (resource == RLIMIT_NOFILE &&
1438 new_rlim->rlim_max > sysctl_nr_open)
1439 return -EPERM;
1440 }
1441
1442 /* protect tsk->signal and tsk->sighand from disappearing */
1443 read_lock(&tasklist_lock);
1444 if (!tsk->sighand) {
1445 retval = -ESRCH;
1446 goto out;
1447 }
1448
1449 rlim = tsk->signal->rlim + resource;
1450 task_lock(tsk->group_leader);
1451 if (new_rlim) {
1452 /* Keep the capable check against init_user_ns until
1453 cgroups can contain all limits */
1454 if (new_rlim->rlim_max > rlim->rlim_max &&
1455 !capable(CAP_SYS_RESOURCE))
1456 retval = -EPERM;
1457 if (!retval)
1458 retval = security_task_setrlimit(tsk->group_leader,
1459 resource, new_rlim);
1460 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1461 /*
1462 * The caller is asking for an immediate RLIMIT_CPU
1463 * expiry. But we use the zero value to mean "it was
1464 * never set". So let's cheat and make it one second
1465 * instead
1466 */
1467 new_rlim->rlim_cur = 1;
1468 }
1469 }
1470 if (!retval) {
1471 if (old_rlim)
1472 *old_rlim = *rlim;
1473 if (new_rlim)
1474 *rlim = *new_rlim;
1475 }
1476 task_unlock(tsk->group_leader);
1477
1478 /*
1479 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1480 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1481 * very long-standing error, and fixing it now risks breakage of
1482 * applications, so we live with it
1483 */
1484 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1485 new_rlim->rlim_cur != RLIM_INFINITY)
1486 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1487 out:
1488 read_unlock(&tasklist_lock);
1489 return retval;
1490 }
1491
1492 /* rcu lock must be held */
1493 static int check_prlimit_permission(struct task_struct *task)
1494 {
1495 const struct cred *cred = current_cred(), *tcred;
1496
1497 if (current == task)
1498 return 0;
1499
1500 tcred = __task_cred(task);
1501 if (cred->user->user_ns == tcred->user->user_ns &&
1502 (cred->uid == tcred->euid &&
1503 cred->uid == tcred->suid &&
1504 cred->uid == tcred->uid &&
1505 cred->gid == tcred->egid &&
1506 cred->gid == tcred->sgid &&
1507 cred->gid == tcred->gid))
1508 return 0;
1509 if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1510 return 0;
1511
1512 return -EPERM;
1513 }
1514
1515 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1516 const struct rlimit64 __user *, new_rlim,
1517 struct rlimit64 __user *, old_rlim)
1518 {
1519 struct rlimit64 old64, new64;
1520 struct rlimit old, new;
1521 struct task_struct *tsk;
1522 int ret;
1523
1524 if (new_rlim) {
1525 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1526 return -EFAULT;
1527 rlim64_to_rlim(&new64, &new);
1528 }
1529
1530 rcu_read_lock();
1531 tsk = pid ? find_task_by_vpid(pid) : current;
1532 if (!tsk) {
1533 rcu_read_unlock();
1534 return -ESRCH;
1535 }
1536 ret = check_prlimit_permission(tsk);
1537 if (ret) {
1538 rcu_read_unlock();
1539 return ret;
1540 }
1541 get_task_struct(tsk);
1542 rcu_read_unlock();
1543
1544 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1545 old_rlim ? &old : NULL);
1546
1547 if (!ret && old_rlim) {
1548 rlim_to_rlim64(&old, &old64);
1549 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1550 ret = -EFAULT;
1551 }
1552
1553 put_task_struct(tsk);
1554 return ret;
1555 }
1556
1557 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1558 {
1559 struct rlimit new_rlim;
1560
1561 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1562 return -EFAULT;
1563 return do_prlimit(current, resource, &new_rlim, NULL);
1564 }
1565
1566 /*
1567 * It would make sense to put struct rusage in the task_struct,
1568 * except that would make the task_struct be *really big*. After
1569 * task_struct gets moved into malloc'ed memory, it would
1570 * make sense to do this. It will make moving the rest of the information
1571 * a lot simpler! (Which we're not doing right now because we're not
1572 * measuring them yet).
1573 *
1574 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1575 * races with threads incrementing their own counters. But since word
1576 * reads are atomic, we either get new values or old values and we don't
1577 * care which for the sums. We always take the siglock to protect reading
1578 * the c* fields from p->signal from races with exit.c updating those
1579 * fields when reaping, so a sample either gets all the additions of a
1580 * given child after it's reaped, or none so this sample is before reaping.
1581 *
1582 * Locking:
1583 * We need to take the siglock for CHILDEREN, SELF and BOTH
1584 * for the cases current multithreaded, non-current single threaded
1585 * non-current multithreaded. Thread traversal is now safe with
1586 * the siglock held.
1587 * Strictly speaking, we donot need to take the siglock if we are current and
1588 * single threaded, as no one else can take our signal_struct away, no one
1589 * else can reap the children to update signal->c* counters, and no one else
1590 * can race with the signal-> fields. If we do not take any lock, the
1591 * signal-> fields could be read out of order while another thread was just
1592 * exiting. So we should place a read memory barrier when we avoid the lock.
1593 * On the writer side, write memory barrier is implied in __exit_signal
1594 * as __exit_signal releases the siglock spinlock after updating the signal->
1595 * fields. But we don't do this yet to keep things simple.
1596 *
1597 */
1598
1599 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1600 {
1601 r->ru_nvcsw += t->nvcsw;
1602 r->ru_nivcsw += t->nivcsw;
1603 r->ru_minflt += t->min_flt;
1604 r->ru_majflt += t->maj_flt;
1605 r->ru_inblock += task_io_get_inblock(t);
1606 r->ru_oublock += task_io_get_oublock(t);
1607 }
1608
1609 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1610 {
1611 struct task_struct *t;
1612 unsigned long flags;
1613 cputime_t tgutime, tgstime, utime, stime;
1614 unsigned long maxrss = 0;
1615
1616 memset((char *) r, 0, sizeof *r);
1617 utime = stime = 0;
1618
1619 if (who == RUSAGE_THREAD) {
1620 task_times(current, &utime, &stime);
1621 accumulate_thread_rusage(p, r);
1622 maxrss = p->signal->maxrss;
1623 goto out;
1624 }
1625
1626 if (!lock_task_sighand(p, &flags))
1627 return;
1628
1629 switch (who) {
1630 case RUSAGE_BOTH:
1631 case RUSAGE_CHILDREN:
1632 utime = p->signal->cutime;
1633 stime = p->signal->cstime;
1634 r->ru_nvcsw = p->signal->cnvcsw;
1635 r->ru_nivcsw = p->signal->cnivcsw;
1636 r->ru_minflt = p->signal->cmin_flt;
1637 r->ru_majflt = p->signal->cmaj_flt;
1638 r->ru_inblock = p->signal->cinblock;
1639 r->ru_oublock = p->signal->coublock;
1640 maxrss = p->signal->cmaxrss;
1641
1642 if (who == RUSAGE_CHILDREN)
1643 break;
1644
1645 case RUSAGE_SELF:
1646 thread_group_times(p, &tgutime, &tgstime);
1647 utime += tgutime;
1648 stime += tgstime;
1649 r->ru_nvcsw += p->signal->nvcsw;
1650 r->ru_nivcsw += p->signal->nivcsw;
1651 r->ru_minflt += p->signal->min_flt;
1652 r->ru_majflt += p->signal->maj_flt;
1653 r->ru_inblock += p->signal->inblock;
1654 r->ru_oublock += p->signal->oublock;
1655 if (maxrss < p->signal->maxrss)
1656 maxrss = p->signal->maxrss;
1657 t = p;
1658 do {
1659 accumulate_thread_rusage(t, r);
1660 t = next_thread(t);
1661 } while (t != p);
1662 break;
1663
1664 default:
1665 BUG();
1666 }
1667 unlock_task_sighand(p, &flags);
1668
1669 out:
1670 cputime_to_timeval(utime, &r->ru_utime);
1671 cputime_to_timeval(stime, &r->ru_stime);
1672
1673 if (who != RUSAGE_CHILDREN) {
1674 struct mm_struct *mm = get_task_mm(p);
1675 if (mm) {
1676 setmax_mm_hiwater_rss(&maxrss, mm);
1677 mmput(mm);
1678 }
1679 }
1680 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1681 }
1682
1683 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1684 {
1685 struct rusage r;
1686 k_getrusage(p, who, &r);
1687 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1688 }
1689
1690 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1691 {
1692 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1693 who != RUSAGE_THREAD)
1694 return -EINVAL;
1695 return getrusage(current, who, ru);
1696 }
1697
1698 SYSCALL_DEFINE1(umask, int, mask)
1699 {
1700 mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1701 return mask;
1702 }
1703
1704 #ifdef CONFIG_CHECKPOINT_RESTORE
1705 static int prctl_set_mm(int opt, unsigned long addr,
1706 unsigned long arg4, unsigned long arg5)
1707 {
1708 unsigned long rlim = rlimit(RLIMIT_DATA);
1709 unsigned long vm_req_flags;
1710 unsigned long vm_bad_flags;
1711 struct vm_area_struct *vma;
1712 int error = 0;
1713 struct mm_struct *mm = current->mm;
1714
1715 if (arg4 | arg5)
1716 return -EINVAL;
1717
1718 if (!capable(CAP_SYS_RESOURCE))
1719 return -EPERM;
1720
1721 if (addr >= TASK_SIZE)
1722 return -EINVAL;
1723
1724 down_read(&mm->mmap_sem);
1725 vma = find_vma(mm, addr);
1726
1727 if (opt != PR_SET_MM_START_BRK && opt != PR_SET_MM_BRK) {
1728 /* It must be existing VMA */
1729 if (!vma || vma->vm_start > addr)
1730 goto out;
1731 }
1732
1733 error = -EINVAL;
1734 switch (opt) {
1735 case PR_SET_MM_START_CODE:
1736 case PR_SET_MM_END_CODE:
1737 vm_req_flags = VM_READ | VM_EXEC;
1738 vm_bad_flags = VM_WRITE | VM_MAYSHARE;
1739
1740 if ((vma->vm_flags & vm_req_flags) != vm_req_flags ||
1741 (vma->vm_flags & vm_bad_flags))
1742 goto out;
1743
1744 if (opt == PR_SET_MM_START_CODE)
1745 mm->start_code = addr;
1746 else
1747 mm->end_code = addr;
1748 break;
1749
1750 case PR_SET_MM_START_DATA:
1751 case PR_SET_MM_END_DATA:
1752 vm_req_flags = VM_READ | VM_WRITE;
1753 vm_bad_flags = VM_EXEC | VM_MAYSHARE;
1754
1755 if ((vma->vm_flags & vm_req_flags) != vm_req_flags ||
1756 (vma->vm_flags & vm_bad_flags))
1757 goto out;
1758
1759 if (opt == PR_SET_MM_START_DATA)
1760 mm->start_data = addr;
1761 else
1762 mm->end_data = addr;
1763 break;
1764
1765 case PR_SET_MM_START_STACK:
1766
1767 #ifdef CONFIG_STACK_GROWSUP
1768 vm_req_flags = VM_READ | VM_WRITE | VM_GROWSUP;
1769 #else
1770 vm_req_flags = VM_READ | VM_WRITE | VM_GROWSDOWN;
1771 #endif
1772 if ((vma->vm_flags & vm_req_flags) != vm_req_flags)
1773 goto out;
1774
1775 mm->start_stack = addr;
1776 break;
1777
1778 case PR_SET_MM_START_BRK:
1779 if (addr <= mm->end_data)
1780 goto out;
1781
1782 if (rlim < RLIM_INFINITY &&
1783 (mm->brk - addr) +
1784 (mm->end_data - mm->start_data) > rlim)
1785 goto out;
1786
1787 mm->start_brk = addr;
1788 break;
1789
1790 case PR_SET_MM_BRK:
1791 if (addr <= mm->end_data)
1792 goto out;
1793
1794 if (rlim < RLIM_INFINITY &&
1795 (addr - mm->start_brk) +
1796 (mm->end_data - mm->start_data) > rlim)
1797 goto out;
1798
1799 mm->brk = addr;
1800 break;
1801
1802 default:
1803 error = -EINVAL;
1804 goto out;
1805 }
1806
1807 error = 0;
1808
1809 out:
1810 up_read(&mm->mmap_sem);
1811
1812 return error;
1813 }
1814 #else /* CONFIG_CHECKPOINT_RESTORE */
1815 static int prctl_set_mm(int opt, unsigned long addr,
1816 unsigned long arg4, unsigned long arg5)
1817 {
1818 return -EINVAL;
1819 }
1820 #endif
1821
1822 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1823 unsigned long, arg4, unsigned long, arg5)
1824 {
1825 struct task_struct *me = current;
1826 unsigned char comm[sizeof(me->comm)];
1827 long error;
1828
1829 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1830 if (error != -ENOSYS)
1831 return error;
1832
1833 error = 0;
1834 switch (option) {
1835 case PR_SET_PDEATHSIG:
1836 if (!valid_signal(arg2)) {
1837 error = -EINVAL;
1838 break;
1839 }
1840 me->pdeath_signal = arg2;
1841 error = 0;
1842 break;
1843 case PR_GET_PDEATHSIG:
1844 error = put_user(me->pdeath_signal, (int __user *)arg2);
1845 break;
1846 case PR_GET_DUMPABLE:
1847 error = get_dumpable(me->mm);
1848 break;
1849 case PR_SET_DUMPABLE:
1850 if (arg2 < 0 || arg2 > 1) {
1851 error = -EINVAL;
1852 break;
1853 }
1854 set_dumpable(me->mm, arg2);
1855 error = 0;
1856 break;
1857
1858 case PR_SET_UNALIGN:
1859 error = SET_UNALIGN_CTL(me, arg2);
1860 break;
1861 case PR_GET_UNALIGN:
1862 error = GET_UNALIGN_CTL(me, arg2);
1863 break;
1864 case PR_SET_FPEMU:
1865 error = SET_FPEMU_CTL(me, arg2);
1866 break;
1867 case PR_GET_FPEMU:
1868 error = GET_FPEMU_CTL(me, arg2);
1869 break;
1870 case PR_SET_FPEXC:
1871 error = SET_FPEXC_CTL(me, arg2);
1872 break;
1873 case PR_GET_FPEXC:
1874 error = GET_FPEXC_CTL(me, arg2);
1875 break;
1876 case PR_GET_TIMING:
1877 error = PR_TIMING_STATISTICAL;
1878 break;
1879 case PR_SET_TIMING:
1880 if (arg2 != PR_TIMING_STATISTICAL)
1881 error = -EINVAL;
1882 else
1883 error = 0;
1884 break;
1885
1886 case PR_SET_NAME:
1887 comm[sizeof(me->comm)-1] = 0;
1888 if (strncpy_from_user(comm, (char __user *)arg2,
1889 sizeof(me->comm) - 1) < 0)
1890 return -EFAULT;
1891 set_task_comm(me, comm);
1892 proc_comm_connector(me);
1893 return 0;
1894 case PR_GET_NAME:
1895 get_task_comm(comm, me);
1896 if (copy_to_user((char __user *)arg2, comm,
1897 sizeof(comm)))
1898 return -EFAULT;
1899 return 0;
1900 case PR_GET_ENDIAN:
1901 error = GET_ENDIAN(me, arg2);
1902 break;
1903 case PR_SET_ENDIAN:
1904 error = SET_ENDIAN(me, arg2);
1905 break;
1906
1907 case PR_GET_SECCOMP:
1908 error = prctl_get_seccomp();
1909 break;
1910 case PR_SET_SECCOMP:
1911 error = prctl_set_seccomp(arg2, (char __user *)arg3);
1912 break;
1913 case PR_GET_TSC:
1914 error = GET_TSC_CTL(arg2);
1915 break;
1916 case PR_SET_TSC:
1917 error = SET_TSC_CTL(arg2);
1918 break;
1919 case PR_TASK_PERF_EVENTS_DISABLE:
1920 error = perf_event_task_disable();
1921 break;
1922 case PR_TASK_PERF_EVENTS_ENABLE:
1923 error = perf_event_task_enable();
1924 break;
1925 case PR_GET_TIMERSLACK:
1926 error = current->timer_slack_ns;
1927 break;
1928 case PR_SET_TIMERSLACK:
1929 if (arg2 <= 0)
1930 current->timer_slack_ns =
1931 current->default_timer_slack_ns;
1932 else
1933 current->timer_slack_ns = arg2;
1934 error = 0;
1935 break;
1936 case PR_MCE_KILL:
1937 if (arg4 | arg5)
1938 return -EINVAL;
1939 switch (arg2) {
1940 case PR_MCE_KILL_CLEAR:
1941 if (arg3 != 0)
1942 return -EINVAL;
1943 current->flags &= ~PF_MCE_PROCESS;
1944 break;
1945 case PR_MCE_KILL_SET:
1946 current->flags |= PF_MCE_PROCESS;
1947 if (arg3 == PR_MCE_KILL_EARLY)
1948 current->flags |= PF_MCE_EARLY;
1949 else if (arg3 == PR_MCE_KILL_LATE)
1950 current->flags &= ~PF_MCE_EARLY;
1951 else if (arg3 == PR_MCE_KILL_DEFAULT)
1952 current->flags &=
1953 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1954 else
1955 return -EINVAL;
1956 break;
1957 default:
1958 return -EINVAL;
1959 }
1960 error = 0;
1961 break;
1962 case PR_MCE_KILL_GET:
1963 if (arg2 | arg3 | arg4 | arg5)
1964 return -EINVAL;
1965 if (current->flags & PF_MCE_PROCESS)
1966 error = (current->flags & PF_MCE_EARLY) ?
1967 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1968 else
1969 error = PR_MCE_KILL_DEFAULT;
1970 break;
1971 case PR_SET_MM:
1972 error = prctl_set_mm(arg2, arg3, arg4, arg5);
1973 break;
1974 case PR_SET_CHILD_SUBREAPER:
1975 me->signal->is_child_subreaper = !!arg2;
1976 error = 0;
1977 break;
1978 case PR_GET_CHILD_SUBREAPER:
1979 error = put_user(me->signal->is_child_subreaper,
1980 (int __user *) arg2);
1981 break;
1982 case PR_SET_NO_NEW_PRIVS:
1983 if (arg2 != 1 || arg3 || arg4 || arg5)
1984 return -EINVAL;
1985
1986 current->no_new_privs = 1;
1987 break;
1988 case PR_GET_NO_NEW_PRIVS:
1989 if (arg2 || arg3 || arg4 || arg5)
1990 return -EINVAL;
1991 return current->no_new_privs ? 1 : 0;
1992 default:
1993 error = -EINVAL;
1994 break;
1995 }
1996 return error;
1997 }
1998
1999 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2000 struct getcpu_cache __user *, unused)
2001 {
2002 int err = 0;
2003 int cpu = raw_smp_processor_id();
2004 if (cpup)
2005 err |= put_user(cpu, cpup);
2006 if (nodep)
2007 err |= put_user(cpu_to_node(cpu), nodep);
2008 return err ? -EFAULT : 0;
2009 }
2010
2011 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
2012
2013 static void argv_cleanup(struct subprocess_info *info)
2014 {
2015 argv_free(info->argv);
2016 }
2017
2018 /**
2019 * orderly_poweroff - Trigger an orderly system poweroff
2020 * @force: force poweroff if command execution fails
2021 *
2022 * This may be called from any context to trigger a system shutdown.
2023 * If the orderly shutdown fails, it will force an immediate shutdown.
2024 */
2025 int orderly_poweroff(bool force)
2026 {
2027 int argc;
2028 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
2029 static char *envp[] = {
2030 "HOME=/",
2031 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2032 NULL
2033 };
2034 int ret = -ENOMEM;
2035 struct subprocess_info *info;
2036
2037 if (argv == NULL) {
2038 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2039 __func__, poweroff_cmd);
2040 goto out;
2041 }
2042
2043 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
2044 if (info == NULL) {
2045 argv_free(argv);
2046 goto out;
2047 }
2048
2049 call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
2050
2051 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
2052
2053 out:
2054 if (ret && force) {
2055 printk(KERN_WARNING "Failed to start orderly shutdown: "
2056 "forcing the issue\n");
2057
2058 /* I guess this should try to kick off some daemon to
2059 sync and poweroff asap. Or not even bother syncing
2060 if we're doing an emergency shutdown? */
2061 emergency_sync();
2062 kernel_power_off();
2063 }
2064
2065 return ret;
2066 }
2067 EXPORT_SYMBOL_GPL(orderly_poweroff);
Linus' kernel tree