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