1 /*
2 * linux/kernel/sys.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/module.h>
8 #include <linux/mm.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/smp_lock.h>
12 #include <linux/notifier.h>
13 #include <linux/reboot.h>
14 #include <linux/prctl.h>
15 #include <linux/highuid.h>
16 #include <linux/fs.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/ptrace.h>
37
38 #include <linux/compat.h>
39 #include <linux/syscalls.h>
40 #include <linux/kprobes.h>
41 #include <linux/user_namespace.h>
42
43 #include <asm/uaccess.h>
44 #include <asm/io.h>
45 #include <asm/unistd.h>
46
47 #ifndef SET_UNALIGN_CTL
48 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
49 #endif
50 #ifndef GET_UNALIGN_CTL
51 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
52 #endif
53 #ifndef SET_FPEMU_CTL
54 # define SET_FPEMU_CTL(a,b) (-EINVAL)
55 #endif
56 #ifndef GET_FPEMU_CTL
57 # define GET_FPEMU_CTL(a,b) (-EINVAL)
58 #endif
59 #ifndef SET_FPEXC_CTL
60 # define SET_FPEXC_CTL(a,b) (-EINVAL)
61 #endif
62 #ifndef GET_FPEXC_CTL
63 # define GET_FPEXC_CTL(a,b) (-EINVAL)
64 #endif
65 #ifndef GET_ENDIAN
66 # define GET_ENDIAN(a,b) (-EINVAL)
67 #endif
68 #ifndef SET_ENDIAN
69 # define SET_ENDIAN(a,b) (-EINVAL)
70 #endif
71 #ifndef GET_TSC_CTL
72 # define GET_TSC_CTL(a) (-EINVAL)
73 #endif
74 #ifndef SET_TSC_CTL
75 # define SET_TSC_CTL(a) (-EINVAL)
76 #endif
77
78 /*
79 * this is where the system-wide overflow UID and GID are defined, for
80 * architectures that now have 32-bit UID/GID but didn't in the past
81 */
82
83 int overflowuid = DEFAULT_OVERFLOWUID;
84 int overflowgid = DEFAULT_OVERFLOWGID;
85
86 #ifdef CONFIG_UID16
87 EXPORT_SYMBOL(overflowuid);
88 EXPORT_SYMBOL(overflowgid);
89 #endif
90
91 /*
92 * the same as above, but for filesystems which can only store a 16-bit
93 * UID and GID. as such, this is needed on all architectures
94 */
95
96 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
97 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
98
99 EXPORT_SYMBOL(fs_overflowuid);
100 EXPORT_SYMBOL(fs_overflowgid);
101
102 /*
103 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
104 */
105
106 int C_A_D = 1;
107 struct pid *cad_pid;
108 EXPORT_SYMBOL(cad_pid);
109
110 /*
111 * If set, this is used for preparing the system to power off.
112 */
113
114 void (*pm_power_off_prepare)(void);
115
116 /*
117 * set the priority of a task
118 * - the caller must hold the RCU read lock
119 */
set_one_prio(struct task_struct * p,int niceval,int error)120 static int set_one_prio(struct task_struct *p, int niceval, int error)
121 {
122 const struct cred *cred = current_cred(), *pcred = __task_cred(p);
123 int no_nice;
124
125 if (pcred->uid != cred->euid &&
126 pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
127 error = -EPERM;
128 goto out;
129 }
130 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
131 error = -EACCES;
132 goto out;
133 }
134 no_nice = security_task_setnice(p, niceval);
135 if (no_nice) {
136 error = no_nice;
137 goto out;
138 }
139 if (error == -ESRCH)
140 error = 0;
141 set_user_nice(p, niceval);
142 out:
143 return error;
144 }
145
SYSCALL_DEFINE3(setpriority,int,which,int,who,int,niceval)146 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
147 {
148 struct task_struct *g, *p;
149 struct user_struct *user;
150 const struct cred *cred = current_cred();
151 int error = -EINVAL;
152 struct pid *pgrp;
153
154 if (which > PRIO_USER || which < PRIO_PROCESS)
155 goto out;
156
157 /* normalize: avoid signed division (rounding problems) */
158 error = -ESRCH;
159 if (niceval < -20)
160 niceval = -20;
161 if (niceval > 19)
162 niceval = 19;
163
164 read_lock(&tasklist_lock);
165 switch (which) {
166 case PRIO_PROCESS:
167 if (who)
168 p = find_task_by_vpid(who);
169 else
170 p = current;
171 if (p)
172 error = set_one_prio(p, niceval, error);
173 break;
174 case PRIO_PGRP:
175 if (who)
176 pgrp = find_vpid(who);
177 else
178 pgrp = task_pgrp(current);
179 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
180 error = set_one_prio(p, niceval, error);
181 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
182 break;
183 case PRIO_USER:
184 user = (struct user_struct *) cred->user;
185 if (!who)
186 who = cred->uid;
187 else if ((who != cred->uid) &&
188 !(user = find_user(who)))
189 goto out_unlock; /* No processes for this user */
190
191 do_each_thread(g, p)
192 if (__task_cred(p)->uid == who)
193 error = set_one_prio(p, niceval, error);
194 while_each_thread(g, p);
195 if (who != cred->uid)
196 free_uid(user); /* For find_user() */
197 break;
198 }
199 out_unlock:
200 read_unlock(&tasklist_lock);
201 out:
202 return error;
203 }
204
205 /*
206 * Ugh. To avoid negative return values, "getpriority()" will
207 * not return the normal nice-value, but a negated value that
208 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
209 * to stay compatible.
210 */
SYSCALL_DEFINE2(getpriority,int,which,int,who)211 SYSCALL_DEFINE2(getpriority, int, which, int, who)
212 {
213 struct task_struct *g, *p;
214 struct user_struct *user;
215 const struct cred *cred = current_cred();
216 long niceval, retval = -ESRCH;
217 struct pid *pgrp;
218
219 if (which > PRIO_USER || which < PRIO_PROCESS)
220 return -EINVAL;
221
222 read_lock(&tasklist_lock);
223 switch (which) {
224 case PRIO_PROCESS:
225 if (who)
226 p = find_task_by_vpid(who);
227 else
228 p = current;
229 if (p) {
230 niceval = 20 - task_nice(p);
231 if (niceval > retval)
232 retval = niceval;
233 }
234 break;
235 case PRIO_PGRP:
236 if (who)
237 pgrp = find_vpid(who);
238 else
239 pgrp = task_pgrp(current);
240 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
241 niceval = 20 - task_nice(p);
242 if (niceval > retval)
243 retval = niceval;
244 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
245 break;
246 case PRIO_USER:
247 user = (struct user_struct *) cred->user;
248 if (!who)
249 who = cred->uid;
250 else if ((who != cred->uid) &&
251 !(user = find_user(who)))
252 goto out_unlock; /* No processes for this user */
253
254 do_each_thread(g, p)
255 if (__task_cred(p)->uid == who) {
256 niceval = 20 - task_nice(p);
257 if (niceval > retval)
258 retval = niceval;
259 }
260 while_each_thread(g, p);
261 if (who != cred->uid)
262 free_uid(user); /* for find_user() */
263 break;
264 }
265 out_unlock:
266 read_unlock(&tasklist_lock);
267
268 return retval;
269 }
270
271 /**
272 * emergency_restart - reboot the system
273 *
274 * Without shutting down any hardware or taking any locks
275 * reboot the system. This is called when we know we are in
276 * trouble so this is our best effort to reboot. This is
277 * safe to call in interrupt context.
278 */
emergency_restart(void)279 void emergency_restart(void)
280 {
281 machine_emergency_restart();
282 }
283 EXPORT_SYMBOL_GPL(emergency_restart);
284
kernel_restart_prepare(char * cmd)285 void kernel_restart_prepare(char *cmd)
286 {
287 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
288 system_state = SYSTEM_RESTART;
289 device_shutdown();
290 sysdev_shutdown();
291 }
292
293 /**
294 * kernel_restart - reboot the system
295 * @cmd: pointer to buffer containing command to execute for restart
296 * or %NULL
297 *
298 * Shutdown everything and perform a clean reboot.
299 * This is not safe to call in interrupt context.
300 */
kernel_restart(char * cmd)301 void kernel_restart(char *cmd)
302 {
303 kernel_restart_prepare(cmd);
304 if (!cmd)
305 printk(KERN_EMERG "Restarting system.\n");
306 else
307 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
308 machine_restart(cmd);
309 }
310 EXPORT_SYMBOL_GPL(kernel_restart);
311
kernel_shutdown_prepare(enum system_states state)312 static void kernel_shutdown_prepare(enum system_states state)
313 {
314 blocking_notifier_call_chain(&reboot_notifier_list,
315 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
316 system_state = state;
317 device_shutdown();
318 }
319 /**
320 * kernel_halt - halt the system
321 *
322 * Shutdown everything and perform a clean system halt.
323 */
kernel_halt(void)324 void kernel_halt(void)
325 {
326 kernel_shutdown_prepare(SYSTEM_HALT);
327 sysdev_shutdown();
328 printk(KERN_EMERG "System halted.\n");
329 machine_halt();
330 }
331
332 EXPORT_SYMBOL_GPL(kernel_halt);
333
334 /**
335 * kernel_power_off - power_off the system
336 *
337 * Shutdown everything and perform a clean system power_off.
338 */
kernel_power_off(void)339 void kernel_power_off(void)
340 {
341 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
342 if (pm_power_off_prepare)
343 pm_power_off_prepare();
344 disable_nonboot_cpus();
345 sysdev_shutdown();
346 printk(KERN_EMERG "Power down.\n");
347 machine_power_off();
348 }
349 EXPORT_SYMBOL_GPL(kernel_power_off);
350 /*
351 * Reboot system call: for obvious reasons only root may call it,
352 * and even root needs to set up some magic numbers in the registers
353 * so that some mistake won't make this reboot the whole machine.
354 * You can also set the meaning of the ctrl-alt-del-key here.
355 *
356 * reboot doesn't sync: do that yourself before calling this.
357 */
SYSCALL_DEFINE4(reboot,int,magic1,int,magic2,unsigned int,cmd,void __user *,arg)358 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
359 void __user *, arg)
360 {
361 char buffer[256];
362
363 /* We only trust the superuser with rebooting the system. */
364 if (!capable(CAP_SYS_BOOT))
365 return -EPERM;
366
367 /* For safety, we require "magic" arguments. */
368 if (magic1 != LINUX_REBOOT_MAGIC1 ||
369 (magic2 != LINUX_REBOOT_MAGIC2 &&
370 magic2 != LINUX_REBOOT_MAGIC2A &&
371 magic2 != LINUX_REBOOT_MAGIC2B &&
372 magic2 != LINUX_REBOOT_MAGIC2C))
373 return -EINVAL;
374
375 /* Instead of trying to make the power_off code look like
376 * halt when pm_power_off is not set do it the easy way.
377 */
378 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
379 cmd = LINUX_REBOOT_CMD_HALT;
380
381 lock_kernel();
382 switch (cmd) {
383 case LINUX_REBOOT_CMD_RESTART:
384 kernel_restart(NULL);
385 break;
386
387 case LINUX_REBOOT_CMD_CAD_ON:
388 C_A_D = 1;
389 break;
390
391 case LINUX_REBOOT_CMD_CAD_OFF:
392 C_A_D = 0;
393 break;
394
395 case LINUX_REBOOT_CMD_HALT:
396 kernel_halt();
397 unlock_kernel();
398 do_exit(0);
399 break;
400
401 case LINUX_REBOOT_CMD_POWER_OFF:
402 kernel_power_off();
403 unlock_kernel();
404 do_exit(0);
405 break;
406
407 case LINUX_REBOOT_CMD_RESTART2:
408 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
409 unlock_kernel();
410 return -EFAULT;
411 }
412 buffer[sizeof(buffer) - 1] = '\0';
413
414 kernel_restart(buffer);
415 break;
416
417 #ifdef CONFIG_KEXEC
418 case LINUX_REBOOT_CMD_KEXEC:
419 {
420 int ret;
421 ret = kernel_kexec();
422 unlock_kernel();
423 return ret;
424 }
425 #endif
426
427 #ifdef CONFIG_HIBERNATION
428 case LINUX_REBOOT_CMD_SW_SUSPEND:
429 {
430 int ret = hibernate();
431 unlock_kernel();
432 return ret;
433 }
434 #endif
435
436 default:
437 unlock_kernel();
438 return -EINVAL;
439 }
440 unlock_kernel();
441 return 0;
442 }
443
deferred_cad(struct work_struct * dummy)444 static void deferred_cad(struct work_struct *dummy)
445 {
446 kernel_restart(NULL);
447 }
448
449 /*
450 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
451 * As it's called within an interrupt, it may NOT sync: the only choice
452 * is whether to reboot at once, or just ignore the ctrl-alt-del.
453 */
ctrl_alt_del(void)454 void ctrl_alt_del(void)
455 {
456 static DECLARE_WORK(cad_work, deferred_cad);
457
458 if (C_A_D)
459 schedule_work(&cad_work);
460 else
461 kill_cad_pid(SIGINT, 1);
462 }
463
464 /*
465 * Unprivileged users may change the real gid to the effective gid
466 * or vice versa. (BSD-style)
467 *
468 * If you set the real gid at all, or set the effective gid to a value not
469 * equal to the real gid, then the saved gid is set to the new effective gid.
470 *
471 * This makes it possible for a setgid program to completely drop its
472 * privileges, which is often a useful assertion to make when you are doing
473 * a security audit over a program.
474 *
475 * The general idea is that a program which uses just setregid() will be
476 * 100% compatible with BSD. A program which uses just setgid() will be
477 * 100% compatible with POSIX with saved IDs.
478 *
479 * SMP: There are not races, the GIDs are checked only by filesystem
480 * operations (as far as semantic preservation is concerned).
481 */
SYSCALL_DEFINE2(setregid,gid_t,rgid,gid_t,egid)482 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
483 {
484 const struct cred *old;
485 struct cred *new;
486 int retval;
487
488 new = prepare_creds();
489 if (!new)
490 return -ENOMEM;
491 old = current_cred();
492
493 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
494 if (retval)
495 goto error;
496
497 retval = -EPERM;
498 if (rgid != (gid_t) -1) {
499 if (old->gid == rgid ||
500 old->egid == rgid ||
501 capable(CAP_SETGID))
502 new->gid = rgid;
503 else
504 goto error;
505 }
506 if (egid != (gid_t) -1) {
507 if (old->gid == egid ||
508 old->egid == egid ||
509 old->sgid == egid ||
510 capable(CAP_SETGID))
511 new->egid = egid;
512 else
513 goto error;
514 }
515
516 if (rgid != (gid_t) -1 ||
517 (egid != (gid_t) -1 && egid != old->gid))
518 new->sgid = new->egid;
519 new->fsgid = new->egid;
520
521 return commit_creds(new);
522
523 error:
524 abort_creds(new);
525 return retval;
526 }
527
528 /*
529 * setgid() is implemented like SysV w/ SAVED_IDS
530 *
531 * SMP: Same implicit races as above.
532 */
SYSCALL_DEFINE1(setgid,gid_t,gid)533 SYSCALL_DEFINE1(setgid, gid_t, gid)
534 {
535 const struct cred *old;
536 struct cred *new;
537 int retval;
538
539 new = prepare_creds();
540 if (!new)
541 return -ENOMEM;
542 old = current_cred();
543
544 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
545 if (retval)
546 goto error;
547
548 retval = -EPERM;
549 if (capable(CAP_SETGID))
550 new->gid = new->egid = new->sgid = new->fsgid = gid;
551 else if (gid == old->gid || gid == old->sgid)
552 new->egid = new->fsgid = gid;
553 else
554 goto error;
555
556 return commit_creds(new);
557
558 error:
559 abort_creds(new);
560 return retval;
561 }
562
563 /*
564 * change the user struct in a credentials set to match the new UID
565 */
set_user(struct cred * new)566 static int set_user(struct cred *new)
567 {
568 struct user_struct *new_user;
569
570 new_user = alloc_uid(current_user_ns(), new->uid);
571 if (!new_user)
572 return -EAGAIN;
573
574 if (!task_can_switch_user(new_user, current)) {
575 free_uid(new_user);
576 return -EINVAL;
577 }
578
579 if (atomic_read(&new_user->processes) >=
580 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
581 new_user != INIT_USER) {
582 free_uid(new_user);
583 return -EAGAIN;
584 }
585
586 free_uid(new->user);
587 new->user = new_user;
588 return 0;
589 }
590
591 /*
592 * Unprivileged users may change the real uid to the effective uid
593 * or vice versa. (BSD-style)
594 *
595 * If you set the real uid at all, or set the effective uid to a value not
596 * equal to the real uid, then the saved uid is set to the new effective uid.
597 *
598 * This makes it possible for a setuid program to completely drop its
599 * privileges, which is often a useful assertion to make when you are doing
600 * a security audit over a program.
601 *
602 * The general idea is that a program which uses just setreuid() will be
603 * 100% compatible with BSD. A program which uses just setuid() will be
604 * 100% compatible with POSIX with saved IDs.
605 */
SYSCALL_DEFINE2(setreuid,uid_t,ruid,uid_t,euid)606 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
607 {
608 const struct cred *old;
609 struct cred *new;
610 int retval;
611
612 new = prepare_creds();
613 if (!new)
614 return -ENOMEM;
615 old = current_cred();
616
617 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
618 if (retval)
619 goto error;
620
621 retval = -EPERM;
622 if (ruid != (uid_t) -1) {
623 new->uid = ruid;
624 if (old->uid != ruid &&
625 old->euid != ruid &&
626 !capable(CAP_SETUID))
627 goto error;
628 }
629
630 if (euid != (uid_t) -1) {
631 new->euid = euid;
632 if (old->uid != euid &&
633 old->euid != euid &&
634 old->suid != euid &&
635 !capable(CAP_SETUID))
636 goto error;
637 }
638
639 if (new->uid != old->uid) {
640 retval = set_user(new);
641 if (retval < 0)
642 goto error;
643 }
644 if (ruid != (uid_t) -1 ||
645 (euid != (uid_t) -1 && euid != old->uid))
646 new->suid = new->euid;
647 new->fsuid = new->euid;
648
649 retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
650 if (retval < 0)
651 goto error;
652
653 return commit_creds(new);
654
655 error:
656 abort_creds(new);
657 return retval;
658 }
659
660 /*
661 * setuid() is implemented like SysV with SAVED_IDS
662 *
663 * Note that SAVED_ID's is deficient in that a setuid root program
664 * like sendmail, for example, cannot set its uid to be a normal
665 * user and then switch back, because if you're root, setuid() sets
666 * the saved uid too. If you don't like this, blame the bright people
667 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
668 * will allow a root program to temporarily drop privileges and be able to
669 * regain them by swapping the real and effective uid.
670 */
SYSCALL_DEFINE1(setuid,uid_t,uid)671 SYSCALL_DEFINE1(setuid, uid_t, uid)
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 = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
683 if (retval)
684 goto error;
685
686 retval = -EPERM;
687 if (capable(CAP_SETUID)) {
688 new->suid = new->uid = uid;
689 if (uid != old->uid) {
690 retval = set_user(new);
691 if (retval < 0)
692 goto error;
693 }
694 } else if (uid != old->uid && uid != new->suid) {
695 goto error;
696 }
697
698 new->fsuid = new->euid = uid;
699
700 retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
701 if (retval < 0)
702 goto error;
703
704 return commit_creds(new);
705
706 error:
707 abort_creds(new);
708 return retval;
709 }
710
711
712 /*
713 * This function implements a generic ability to update ruid, euid,
714 * and suid. This allows you to implement the 4.4 compatible seteuid().
715 */
SYSCALL_DEFINE3(setresuid,uid_t,ruid,uid_t,euid,uid_t,suid)716 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
717 {
718 const struct cred *old;
719 struct cred *new;
720 int retval;
721
722 new = prepare_creds();
723 if (!new)
724 return -ENOMEM;
725
726 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
727 if (retval)
728 goto error;
729 old = current_cred();
730
731 retval = -EPERM;
732 if (!capable(CAP_SETUID)) {
733 if (ruid != (uid_t) -1 && ruid != old->uid &&
734 ruid != old->euid && ruid != old->suid)
735 goto error;
736 if (euid != (uid_t) -1 && euid != old->uid &&
737 euid != old->euid && euid != old->suid)
738 goto error;
739 if (suid != (uid_t) -1 && suid != old->uid &&
740 suid != old->euid && suid != old->suid)
741 goto error;
742 }
743
744 if (ruid != (uid_t) -1) {
745 new->uid = ruid;
746 if (ruid != old->uid) {
747 retval = set_user(new);
748 if (retval < 0)
749 goto error;
750 }
751 }
752 if (euid != (uid_t) -1)
753 new->euid = euid;
754 if (suid != (uid_t) -1)
755 new->suid = suid;
756 new->fsuid = new->euid;
757
758 retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
759 if (retval < 0)
760 goto error;
761
762 return commit_creds(new);
763
764 error:
765 abort_creds(new);
766 return retval;
767 }
768
SYSCALL_DEFINE3(getresuid,uid_t __user *,ruid,uid_t __user *,euid,uid_t __user *,suid)769 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
770 {
771 const struct cred *cred = current_cred();
772 int retval;
773
774 if (!(retval = put_user(cred->uid, ruid)) &&
775 !(retval = put_user(cred->euid, euid)))
776 retval = put_user(cred->suid, suid);
777
778 return retval;
779 }
780
781 /*
782 * Same as above, but for rgid, egid, sgid.
783 */
SYSCALL_DEFINE3(setresgid,gid_t,rgid,gid_t,egid,gid_t,sgid)784 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
785 {
786 const struct cred *old;
787 struct cred *new;
788 int retval;
789
790 new = prepare_creds();
791 if (!new)
792 return -ENOMEM;
793 old = current_cred();
794
795 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
796 if (retval)
797 goto error;
798
799 retval = -EPERM;
800 if (!capable(CAP_SETGID)) {
801 if (rgid != (gid_t) -1 && rgid != old->gid &&
802 rgid != old->egid && rgid != old->sgid)
803 goto error;
804 if (egid != (gid_t) -1 && egid != old->gid &&
805 egid != old->egid && egid != old->sgid)
806 goto error;
807 if (sgid != (gid_t) -1 && sgid != old->gid &&
808 sgid != old->egid && sgid != old->sgid)
809 goto error;
810 }
811
812 if (rgid != (gid_t) -1)
813 new->gid = rgid;
814 if (egid != (gid_t) -1)
815 new->egid = egid;
816 if (sgid != (gid_t) -1)
817 new->sgid = sgid;
818 new->fsgid = new->egid;
819
820 return commit_creds(new);
821
822 error:
823 abort_creds(new);
824 return retval;
825 }
826
SYSCALL_DEFINE3(getresgid,gid_t __user *,rgid,gid_t __user *,egid,gid_t __user *,sgid)827 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
828 {
829 const struct cred *cred = current_cred();
830 int retval;
831
832 if (!(retval = put_user(cred->gid, rgid)) &&
833 !(retval = put_user(cred->egid, egid)))
834 retval = put_user(cred->sgid, sgid);
835
836 return retval;
837 }
838
839
840 /*
841 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
842 * is used for "access()" and for the NFS daemon (letting nfsd stay at
843 * whatever uid it wants to). It normally shadows "euid", except when
844 * explicitly set by setfsuid() or for access..
845 */
SYSCALL_DEFINE1(setfsuid,uid_t,uid)846 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
847 {
848 const struct cred *old;
849 struct cred *new;
850 uid_t old_fsuid;
851
852 new = prepare_creds();
853 if (!new)
854 return current_fsuid();
855 old = current_cred();
856 old_fsuid = old->fsuid;
857
858 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS) < 0)
859 goto error;
860
861 if (uid == old->uid || uid == old->euid ||
862 uid == old->suid || uid == old->fsuid ||
863 capable(CAP_SETUID)) {
864 if (uid != old_fsuid) {
865 new->fsuid = uid;
866 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
867 goto change_okay;
868 }
869 }
870
871 error:
872 abort_creds(new);
873 return old_fsuid;
874
875 change_okay:
876 commit_creds(new);
877 return old_fsuid;
878 }
879
880 /*
881 * Samma på svenska..
882 */
SYSCALL_DEFINE1(setfsgid,gid_t,gid)883 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
884 {
885 const struct cred *old;
886 struct cred *new;
887 gid_t old_fsgid;
888
889 new = prepare_creds();
890 if (!new)
891 return current_fsgid();
892 old = current_cred();
893 old_fsgid = old->fsgid;
894
895 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
896 goto error;
897
898 if (gid == old->gid || gid == old->egid ||
899 gid == old->sgid || gid == old->fsgid ||
900 capable(CAP_SETGID)) {
901 if (gid != old_fsgid) {
902 new->fsgid = gid;
903 goto change_okay;
904 }
905 }
906
907 error:
908 abort_creds(new);
909 return old_fsgid;
910
911 change_okay:
912 commit_creds(new);
913 return old_fsgid;
914 }
915
do_sys_times(struct tms * tms)916 void do_sys_times(struct tms *tms)
917 {
918 struct task_cputime cputime;
919 cputime_t cutime, cstime;
920
921 thread_group_cputime(current, &cputime);
922 spin_lock_irq(¤t->sighand->siglock);
923 cutime = current->signal->cutime;
924 cstime = current->signal->cstime;
925 spin_unlock_irq(¤t->sighand->siglock);
926 tms->tms_utime = cputime_to_clock_t(cputime.utime);
927 tms->tms_stime = cputime_to_clock_t(cputime.stime);
928 tms->tms_cutime = cputime_to_clock_t(cutime);
929 tms->tms_cstime = cputime_to_clock_t(cstime);
930 }
931
SYSCALL_DEFINE1(times,struct tms __user *,tbuf)932 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
933 {
934 if (tbuf) {
935 struct tms tmp;
936
937 do_sys_times(&tmp);
938 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
939 return -EFAULT;
940 }
941 force_successful_syscall_return();
942 return (long) jiffies_64_to_clock_t(get_jiffies_64());
943 }
944
945 /*
946 * This needs some heavy checking ...
947 * I just haven't the stomach for it. I also don't fully
948 * understand sessions/pgrp etc. Let somebody who does explain it.
949 *
950 * OK, I think I have the protection semantics right.... this is really
951 * only important on a multi-user system anyway, to make sure one user
952 * can't send a signal to a process owned by another. -TYT, 12/12/91
953 *
954 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
955 * LBT 04.03.94
956 */
SYSCALL_DEFINE2(setpgid,pid_t,pid,pid_t,pgid)957 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
958 {
959 struct task_struct *p;
960 struct task_struct *group_leader = current->group_leader;
961 struct pid *pgrp;
962 int err;
963
964 if (!pid)
965 pid = task_pid_vnr(group_leader);
966 if (!pgid)
967 pgid = pid;
968 if (pgid < 0)
969 return -EINVAL;
970
971 /* From this point forward we keep holding onto the tasklist lock
972 * so that our parent does not change from under us. -DaveM
973 */
974 write_lock_irq(&tasklist_lock);
975
976 err = -ESRCH;
977 p = find_task_by_vpid(pid);
978 if (!p)
979 goto out;
980
981 err = -EINVAL;
982 if (!thread_group_leader(p))
983 goto out;
984
985 if (same_thread_group(p->real_parent, group_leader)) {
986 err = -EPERM;
987 if (task_session(p) != task_session(group_leader))
988 goto out;
989 err = -EACCES;
990 if (p->did_exec)
991 goto out;
992 } else {
993 err = -ESRCH;
994 if (p != group_leader)
995 goto out;
996 }
997
998 err = -EPERM;
999 if (p->signal->leader)
1000 goto out;
1001
1002 pgrp = task_pid(p);
1003 if (pgid != pid) {
1004 struct task_struct *g;
1005
1006 pgrp = find_vpid(pgid);
1007 g = pid_task(pgrp, PIDTYPE_PGID);
1008 if (!g || task_session(g) != task_session(group_leader))
1009 goto out;
1010 }
1011
1012 err = security_task_setpgid(p, pgid);
1013 if (err)
1014 goto out;
1015
1016 if (task_pgrp(p) != pgrp) {
1017 change_pid(p, PIDTYPE_PGID, pgrp);
1018 set_task_pgrp(p, pid_nr(pgrp));
1019 }
1020
1021 err = 0;
1022 out:
1023 /* All paths lead to here, thus we are safe. -DaveM */
1024 write_unlock_irq(&tasklist_lock);
1025 return err;
1026 }
1027
SYSCALL_DEFINE1(getpgid,pid_t,pid)1028 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1029 {
1030 struct task_struct *p;
1031 struct pid *grp;
1032 int retval;
1033
1034 rcu_read_lock();
1035 if (!pid)
1036 grp = task_pgrp(current);
1037 else {
1038 retval = -ESRCH;
1039 p = find_task_by_vpid(pid);
1040 if (!p)
1041 goto out;
1042 grp = task_pgrp(p);
1043 if (!grp)
1044 goto out;
1045
1046 retval = security_task_getpgid(p);
1047 if (retval)
1048 goto out;
1049 }
1050 retval = pid_vnr(grp);
1051 out:
1052 rcu_read_unlock();
1053 return retval;
1054 }
1055
1056 #ifdef __ARCH_WANT_SYS_GETPGRP
1057
SYSCALL_DEFINE0(getpgrp)1058 SYSCALL_DEFINE0(getpgrp)
1059 {
1060 return sys_getpgid(0);
1061 }
1062
1063 #endif
1064
SYSCALL_DEFINE1(getsid,pid_t,pid)1065 SYSCALL_DEFINE1(getsid, pid_t, pid)
1066 {
1067 struct task_struct *p;
1068 struct pid *sid;
1069 int retval;
1070
1071 rcu_read_lock();
1072 if (!pid)
1073 sid = task_session(current);
1074 else {
1075 retval = -ESRCH;
1076 p = find_task_by_vpid(pid);
1077 if (!p)
1078 goto out;
1079 sid = task_session(p);
1080 if (!sid)
1081 goto out;
1082
1083 retval = security_task_getsid(p);
1084 if (retval)
1085 goto out;
1086 }
1087 retval = pid_vnr(sid);
1088 out:
1089 rcu_read_unlock();
1090 return retval;
1091 }
1092
SYSCALL_DEFINE0(setsid)1093 SYSCALL_DEFINE0(setsid)
1094 {
1095 struct task_struct *group_leader = current->group_leader;
1096 struct pid *sid = task_pid(group_leader);
1097 pid_t session = pid_vnr(sid);
1098 int err = -EPERM;
1099
1100 write_lock_irq(&tasklist_lock);
1101 /* Fail if I am already a session leader */
1102 if (group_leader->signal->leader)
1103 goto out;
1104
1105 /* Fail if a process group id already exists that equals the
1106 * proposed session id.
1107 */
1108 if (pid_task(sid, PIDTYPE_PGID))
1109 goto out;
1110
1111 group_leader->signal->leader = 1;
1112 __set_special_pids(sid);
1113
1114 proc_clear_tty(group_leader);
1115
1116 err = session;
1117 out:
1118 write_unlock_irq(&tasklist_lock);
1119 return err;
1120 }
1121
1122 /*
1123 * Supplementary group IDs
1124 */
1125
1126 /* init to 2 - one for init_task, one to ensure it is never freed */
1127 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1128
groups_alloc(int gidsetsize)1129 struct group_info *groups_alloc(int gidsetsize)
1130 {
1131 struct group_info *group_info;
1132 int nblocks;
1133 int i;
1134
1135 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1136 /* Make sure we always allocate at least one indirect block pointer */
1137 nblocks = nblocks ? : 1;
1138 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1139 if (!group_info)
1140 return NULL;
1141 group_info->ngroups = gidsetsize;
1142 group_info->nblocks = nblocks;
1143 atomic_set(&group_info->usage, 1);
1144
1145 if (gidsetsize <= NGROUPS_SMALL)
1146 group_info->blocks[0] = group_info->small_block;
1147 else {
1148 for (i = 0; i < nblocks; i++) {
1149 gid_t *b;
1150 b = (void *)__get_free_page(GFP_USER);
1151 if (!b)
1152 goto out_undo_partial_alloc;
1153 group_info->blocks[i] = b;
1154 }
1155 }
1156 return group_info;
1157
1158 out_undo_partial_alloc:
1159 while (--i >= 0) {
1160 free_page((unsigned long)group_info->blocks[i]);
1161 }
1162 kfree(group_info);
1163 return NULL;
1164 }
1165
1166 EXPORT_SYMBOL(groups_alloc);
1167
groups_free(struct group_info * group_info)1168 void groups_free(struct group_info *group_info)
1169 {
1170 if (group_info->blocks[0] != group_info->small_block) {
1171 int i;
1172 for (i = 0; i < group_info->nblocks; i++)
1173 free_page((unsigned long)group_info->blocks[i]);
1174 }
1175 kfree(group_info);
1176 }
1177
1178 EXPORT_SYMBOL(groups_free);
1179
1180 /* export the group_info to a user-space array */
groups_to_user(gid_t __user * grouplist,const struct group_info * group_info)1181 static int groups_to_user(gid_t __user *grouplist,
1182 const struct group_info *group_info)
1183 {
1184 int i;
1185 unsigned int count = group_info->ngroups;
1186
1187 for (i = 0; i < group_info->nblocks; i++) {
1188 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1189 unsigned int len = cp_count * sizeof(*grouplist);
1190
1191 if (copy_to_user(grouplist, group_info->blocks[i], len))
1192 return -EFAULT;
1193
1194 grouplist += NGROUPS_PER_BLOCK;
1195 count -= cp_count;
1196 }
1197 return 0;
1198 }
1199
1200 /* fill a group_info from a user-space array - it must be allocated already */
groups_from_user(struct group_info * group_info,gid_t __user * grouplist)1201 static int groups_from_user(struct group_info *group_info,
1202 gid_t __user *grouplist)
1203 {
1204 int i;
1205 unsigned int count = group_info->ngroups;
1206
1207 for (i = 0; i < group_info->nblocks; i++) {
1208 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1209 unsigned int len = cp_count * sizeof(*grouplist);
1210
1211 if (copy_from_user(group_info->blocks[i], grouplist, len))
1212 return -EFAULT;
1213
1214 grouplist += NGROUPS_PER_BLOCK;
1215 count -= cp_count;
1216 }
1217 return 0;
1218 }
1219
1220 /* a simple Shell sort */
groups_sort(struct group_info * group_info)1221 static void groups_sort(struct group_info *group_info)
1222 {
1223 int base, max, stride;
1224 int gidsetsize = group_info->ngroups;
1225
1226 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1227 ; /* nothing */
1228 stride /= 3;
1229
1230 while (stride) {
1231 max = gidsetsize - stride;
1232 for (base = 0; base < max; base++) {
1233 int left = base;
1234 int right = left + stride;
1235 gid_t tmp = GROUP_AT(group_info, right);
1236
1237 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1238 GROUP_AT(group_info, right) =
1239 GROUP_AT(group_info, left);
1240 right = left;
1241 left -= stride;
1242 }
1243 GROUP_AT(group_info, right) = tmp;
1244 }
1245 stride /= 3;
1246 }
1247 }
1248
1249 /* a simple bsearch */
groups_search(const struct group_info * group_info,gid_t grp)1250 int groups_search(const struct group_info *group_info, gid_t grp)
1251 {
1252 unsigned int left, right;
1253
1254 if (!group_info)
1255 return 0;
1256
1257 left = 0;
1258 right = group_info->ngroups;
1259 while (left < right) {
1260 unsigned int mid = (left+right)/2;
1261 int cmp = grp - GROUP_AT(group_info, mid);
1262 if (cmp > 0)
1263 left = mid + 1;
1264 else if (cmp < 0)
1265 right = mid;
1266 else
1267 return 1;
1268 }
1269 return 0;
1270 }
1271
1272 /**
1273 * set_groups - Change a group subscription in a set of credentials
1274 * @new: The newly prepared set of credentials to alter
1275 * @group_info: The group list to install
1276 *
1277 * Validate a group subscription and, if valid, insert it into a set
1278 * of credentials.
1279 */
set_groups(struct cred * new,struct group_info * group_info)1280 int set_groups(struct cred *new, struct group_info *group_info)
1281 {
1282 int retval;
1283
1284 retval = security_task_setgroups(group_info);
1285 if (retval)
1286 return retval;
1287
1288 put_group_info(new->group_info);
1289 groups_sort(group_info);
1290 get_group_info(group_info);
1291 new->group_info = group_info;
1292 return 0;
1293 }
1294
1295 EXPORT_SYMBOL(set_groups);
1296
1297 /**
1298 * set_current_groups - Change current's group subscription
1299 * @group_info: The group list to impose
1300 *
1301 * Validate a group subscription and, if valid, impose it upon current's task
1302 * security record.
1303 */
set_current_groups(struct group_info * group_info)1304 int set_current_groups(struct group_info *group_info)
1305 {
1306 struct cred *new;
1307 int ret;
1308
1309 new = prepare_creds();
1310 if (!new)
1311 return -ENOMEM;
1312
1313 ret = set_groups(new, group_info);
1314 if (ret < 0) {
1315 abort_creds(new);
1316 return ret;
1317 }
1318
1319 return commit_creds(new);
1320 }
1321
1322 EXPORT_SYMBOL(set_current_groups);
1323
SYSCALL_DEFINE2(getgroups,int,gidsetsize,gid_t __user *,grouplist)1324 SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist)
1325 {
1326 const struct cred *cred = current_cred();
1327 int i;
1328
1329 if (gidsetsize < 0)
1330 return -EINVAL;
1331
1332 /* no need to grab task_lock here; it cannot change */
1333 i = cred->group_info->ngroups;
1334 if (gidsetsize) {
1335 if (i > gidsetsize) {
1336 i = -EINVAL;
1337 goto out;
1338 }
1339 if (groups_to_user(grouplist, cred->group_info)) {
1340 i = -EFAULT;
1341 goto out;
1342 }
1343 }
1344 out:
1345 return i;
1346 }
1347
1348 /*
1349 * SMP: Our groups are copy-on-write. We can set them safely
1350 * without another task interfering.
1351 */
1352
SYSCALL_DEFINE2(setgroups,int,gidsetsize,gid_t __user *,grouplist)1353 SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
1354 {
1355 struct group_info *group_info;
1356 int retval;
1357
1358 if (!capable(CAP_SETGID))
1359 return -EPERM;
1360 if ((unsigned)gidsetsize > NGROUPS_MAX)
1361 return -EINVAL;
1362
1363 group_info = groups_alloc(gidsetsize);
1364 if (!group_info)
1365 return -ENOMEM;
1366 retval = groups_from_user(group_info, grouplist);
1367 if (retval) {
1368 put_group_info(group_info);
1369 return retval;
1370 }
1371
1372 retval = set_current_groups(group_info);
1373 put_group_info(group_info);
1374
1375 return retval;
1376 }
1377
1378 /*
1379 * Check whether we're fsgid/egid or in the supplemental group..
1380 */
in_group_p(gid_t grp)1381 int in_group_p(gid_t grp)
1382 {
1383 const struct cred *cred = current_cred();
1384 int retval = 1;
1385
1386 if (grp != cred->fsgid)
1387 retval = groups_search(cred->group_info, grp);
1388 return retval;
1389 }
1390
1391 EXPORT_SYMBOL(in_group_p);
1392
in_egroup_p(gid_t grp)1393 int in_egroup_p(gid_t grp)
1394 {
1395 const struct cred *cred = current_cred();
1396 int retval = 1;
1397
1398 if (grp != cred->egid)
1399 retval = groups_search(cred->group_info, grp);
1400 return retval;
1401 }
1402
1403 EXPORT_SYMBOL(in_egroup_p);
1404
1405 DECLARE_RWSEM(uts_sem);
1406
SYSCALL_DEFINE1(newuname,struct new_utsname __user *,name)1407 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1408 {
1409 int errno = 0;
1410
1411 down_read(&uts_sem);
1412 if (copy_to_user(name, utsname(), sizeof *name))
1413 errno = -EFAULT;
1414 up_read(&uts_sem);
1415 return errno;
1416 }
1417
SYSCALL_DEFINE2(sethostname,char __user *,name,int,len)1418 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1419 {
1420 int errno;
1421 char tmp[__NEW_UTS_LEN];
1422
1423 if (!capable(CAP_SYS_ADMIN))
1424 return -EPERM;
1425 if (len < 0 || len > __NEW_UTS_LEN)
1426 return -EINVAL;
1427 down_write(&uts_sem);
1428 errno = -EFAULT;
1429 if (!copy_from_user(tmp, name, len)) {
1430 struct new_utsname *u = utsname();
1431
1432 memcpy(u->nodename, tmp, len);
1433 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1434 errno = 0;
1435 }
1436 up_write(&uts_sem);
1437 return errno;
1438 }
1439
1440 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1441
SYSCALL_DEFINE2(gethostname,char __user *,name,int,len)1442 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1443 {
1444 int i, errno;
1445 struct new_utsname *u;
1446
1447 if (len < 0)
1448 return -EINVAL;
1449 down_read(&uts_sem);
1450 u = utsname();
1451 i = 1 + strlen(u->nodename);
1452 if (i > len)
1453 i = len;
1454 errno = 0;
1455 if (copy_to_user(name, u->nodename, i))
1456 errno = -EFAULT;
1457 up_read(&uts_sem);
1458 return errno;
1459 }
1460
1461 #endif
1462
1463 /*
1464 * Only setdomainname; getdomainname can be implemented by calling
1465 * uname()
1466 */
SYSCALL_DEFINE2(setdomainname,char __user *,name,int,len)1467 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1468 {
1469 int errno;
1470 char tmp[__NEW_UTS_LEN];
1471
1472 if (!capable(CAP_SYS_ADMIN))
1473 return -EPERM;
1474 if (len < 0 || len > __NEW_UTS_LEN)
1475 return -EINVAL;
1476
1477 down_write(&uts_sem);
1478 errno = -EFAULT;
1479 if (!copy_from_user(tmp, name, len)) {
1480 struct new_utsname *u = utsname();
1481
1482 memcpy(u->domainname, tmp, len);
1483 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1484 errno = 0;
1485 }
1486 up_write(&uts_sem);
1487 return errno;
1488 }
1489
SYSCALL_DEFINE2(getrlimit,unsigned int,resource,struct rlimit __user *,rlim)1490 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1491 {
1492 if (resource >= RLIM_NLIMITS)
1493 return -EINVAL;
1494 else {
1495 struct rlimit value;
1496 task_lock(current->group_leader);
1497 value = current->signal->rlim[resource];
1498 task_unlock(current->group_leader);
1499 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1500 }
1501 }
1502
1503 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1504
1505 /*
1506 * Back compatibility for getrlimit. Needed for some apps.
1507 */
1508
SYSCALL_DEFINE2(old_getrlimit,unsigned int,resource,struct rlimit __user *,rlim)1509 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1510 struct rlimit __user *, rlim)
1511 {
1512 struct rlimit x;
1513 if (resource >= RLIM_NLIMITS)
1514 return -EINVAL;
1515
1516 task_lock(current->group_leader);
1517 x = current->signal->rlim[resource];
1518 task_unlock(current->group_leader);
1519 if (x.rlim_cur > 0x7FFFFFFF)
1520 x.rlim_cur = 0x7FFFFFFF;
1521 if (x.rlim_max > 0x7FFFFFFF)
1522 x.rlim_max = 0x7FFFFFFF;
1523 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1524 }
1525
1526 #endif
1527
SYSCALL_DEFINE2(setrlimit,unsigned int,resource,struct rlimit __user *,rlim)1528 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1529 {
1530 struct rlimit new_rlim, *old_rlim;
1531 int retval;
1532
1533 if (resource >= RLIM_NLIMITS)
1534 return -EINVAL;
1535 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1536 return -EFAULT;
1537 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1538 return -EINVAL;
1539 old_rlim = current->signal->rlim + resource;
1540 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1541 !capable(CAP_SYS_RESOURCE))
1542 return -EPERM;
1543 if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1544 return -EPERM;
1545
1546 retval = security_task_setrlimit(resource, &new_rlim);
1547 if (retval)
1548 return retval;
1549
1550 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1551 /*
1552 * The caller is asking for an immediate RLIMIT_CPU
1553 * expiry. But we use the zero value to mean "it was
1554 * never set". So let's cheat and make it one second
1555 * instead
1556 */
1557 new_rlim.rlim_cur = 1;
1558 }
1559
1560 task_lock(current->group_leader);
1561 *old_rlim = new_rlim;
1562 task_unlock(current->group_leader);
1563
1564 if (resource != RLIMIT_CPU)
1565 goto out;
1566
1567 /*
1568 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1569 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1570 * very long-standing error, and fixing it now risks breakage of
1571 * applications, so we live with it
1572 */
1573 if (new_rlim.rlim_cur == RLIM_INFINITY)
1574 goto out;
1575
1576 update_rlimit_cpu(new_rlim.rlim_cur);
1577 out:
1578 return 0;
1579 }
1580
1581 /*
1582 * It would make sense to put struct rusage in the task_struct,
1583 * except that would make the task_struct be *really big*. After
1584 * task_struct gets moved into malloc'ed memory, it would
1585 * make sense to do this. It will make moving the rest of the information
1586 * a lot simpler! (Which we're not doing right now because we're not
1587 * measuring them yet).
1588 *
1589 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1590 * races with threads incrementing their own counters. But since word
1591 * reads are atomic, we either get new values or old values and we don't
1592 * care which for the sums. We always take the siglock to protect reading
1593 * the c* fields from p->signal from races with exit.c updating those
1594 * fields when reaping, so a sample either gets all the additions of a
1595 * given child after it's reaped, or none so this sample is before reaping.
1596 *
1597 * Locking:
1598 * We need to take the siglock for CHILDEREN, SELF and BOTH
1599 * for the cases current multithreaded, non-current single threaded
1600 * non-current multithreaded. Thread traversal is now safe with
1601 * the siglock held.
1602 * Strictly speaking, we donot need to take the siglock if we are current and
1603 * single threaded, as no one else can take our signal_struct away, no one
1604 * else can reap the children to update signal->c* counters, and no one else
1605 * can race with the signal-> fields. If we do not take any lock, the
1606 * signal-> fields could be read out of order while another thread was just
1607 * exiting. So we should place a read memory barrier when we avoid the lock.
1608 * On the writer side, write memory barrier is implied in __exit_signal
1609 * as __exit_signal releases the siglock spinlock after updating the signal->
1610 * fields. But we don't do this yet to keep things simple.
1611 *
1612 */
1613
accumulate_thread_rusage(struct task_struct * t,struct rusage * r)1614 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1615 {
1616 r->ru_nvcsw += t->nvcsw;
1617 r->ru_nivcsw += t->nivcsw;
1618 r->ru_minflt += t->min_flt;
1619 r->ru_majflt += t->maj_flt;
1620 r->ru_inblock += task_io_get_inblock(t);
1621 r->ru_oublock += task_io_get_oublock(t);
1622 }
1623
k_getrusage(struct task_struct * p,int who,struct rusage * r)1624 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1625 {
1626 struct task_struct *t;
1627 unsigned long flags;
1628 cputime_t utime, stime;
1629 struct task_cputime cputime;
1630
1631 memset((char *) r, 0, sizeof *r);
1632 utime = stime = cputime_zero;
1633
1634 if (who == RUSAGE_THREAD) {
1635 utime = task_utime(current);
1636 stime = task_stime(current);
1637 accumulate_thread_rusage(p, r);
1638 goto out;
1639 }
1640
1641 if (!lock_task_sighand(p, &flags))
1642 return;
1643
1644 switch (who) {
1645 case RUSAGE_BOTH:
1646 case RUSAGE_CHILDREN:
1647 utime = p->signal->cutime;
1648 stime = p->signal->cstime;
1649 r->ru_nvcsw = p->signal->cnvcsw;
1650 r->ru_nivcsw = p->signal->cnivcsw;
1651 r->ru_minflt = p->signal->cmin_flt;
1652 r->ru_majflt = p->signal->cmaj_flt;
1653 r->ru_inblock = p->signal->cinblock;
1654 r->ru_oublock = p->signal->coublock;
1655
1656 if (who == RUSAGE_CHILDREN)
1657 break;
1658
1659 case RUSAGE_SELF:
1660 thread_group_cputime(p, &cputime);
1661 utime = cputime_add(utime, cputime.utime);
1662 stime = cputime_add(stime, cputime.stime);
1663 r->ru_nvcsw += p->signal->nvcsw;
1664 r->ru_nivcsw += p->signal->nivcsw;
1665 r->ru_minflt += p->signal->min_flt;
1666 r->ru_majflt += p->signal->maj_flt;
1667 r->ru_inblock += p->signal->inblock;
1668 r->ru_oublock += p->signal->oublock;
1669 t = p;
1670 do {
1671 accumulate_thread_rusage(t, r);
1672 t = next_thread(t);
1673 } while (t != p);
1674 break;
1675
1676 default:
1677 BUG();
1678 }
1679 unlock_task_sighand(p, &flags);
1680
1681 out:
1682 cputime_to_timeval(utime, &r->ru_utime);
1683 cputime_to_timeval(stime, &r->ru_stime);
1684 }
1685
getrusage(struct task_struct * p,int who,struct rusage __user * ru)1686 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1687 {
1688 struct rusage r;
1689 k_getrusage(p, who, &r);
1690 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1691 }
1692
SYSCALL_DEFINE2(getrusage,int,who,struct rusage __user *,ru)1693 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1694 {
1695 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1696 who != RUSAGE_THREAD)
1697 return -EINVAL;
1698 return getrusage(current, who, ru);
1699 }
1700
SYSCALL_DEFINE1(umask,int,mask)1701 SYSCALL_DEFINE1(umask, int, mask)
1702 {
1703 mask = xchg(¤t->fs->umask, mask & S_IRWXUGO);
1704 return mask;
1705 }
1706
SYSCALL_DEFINE5(prctl,int,option,unsigned long,arg2,unsigned long,arg3,unsigned long,arg4,unsigned long,arg5)1707 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1708 unsigned long, arg4, unsigned long, arg5)
1709 {
1710 struct task_struct *me = current;
1711 unsigned char comm[sizeof(me->comm)];
1712 long error;
1713
1714 error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1715 if (error != -ENOSYS)
1716 return error;
1717
1718 error = 0;
1719 switch (option) {
1720 case PR_SET_PDEATHSIG:
1721 if (!valid_signal(arg2)) {
1722 error = -EINVAL;
1723 break;
1724 }
1725 me->pdeath_signal = arg2;
1726 error = 0;
1727 break;
1728 case PR_GET_PDEATHSIG:
1729 error = put_user(me->pdeath_signal, (int __user *)arg2);
1730 break;
1731 case PR_GET_DUMPABLE:
1732 error = get_dumpable(me->mm);
1733 break;
1734 case PR_SET_DUMPABLE:
1735 if (arg2 < 0 || arg2 > 1) {
1736 error = -EINVAL;
1737 break;
1738 }
1739 set_dumpable(me->mm, arg2);
1740 error = 0;
1741 break;
1742
1743 case PR_SET_UNALIGN:
1744 error = SET_UNALIGN_CTL(me, arg2);
1745 break;
1746 case PR_GET_UNALIGN:
1747 error = GET_UNALIGN_CTL(me, arg2);
1748 break;
1749 case PR_SET_FPEMU:
1750 error = SET_FPEMU_CTL(me, arg2);
1751 break;
1752 case PR_GET_FPEMU:
1753 error = GET_FPEMU_CTL(me, arg2);
1754 break;
1755 case PR_SET_FPEXC:
1756 error = SET_FPEXC_CTL(me, arg2);
1757 break;
1758 case PR_GET_FPEXC:
1759 error = GET_FPEXC_CTL(me, arg2);
1760 break;
1761 case PR_GET_TIMING:
1762 error = PR_TIMING_STATISTICAL;
1763 break;
1764 case PR_SET_TIMING:
1765 if (arg2 != PR_TIMING_STATISTICAL)
1766 error = -EINVAL;
1767 else
1768 error = 0;
1769 break;
1770
1771 case PR_SET_NAME:
1772 comm[sizeof(me->comm)-1] = 0;
1773 if (strncpy_from_user(comm, (char __user *)arg2,
1774 sizeof(me->comm) - 1) < 0)
1775 return -EFAULT;
1776 set_task_comm(me, comm);
1777 return 0;
1778 case PR_GET_NAME:
1779 get_task_comm(comm, me);
1780 if (copy_to_user((char __user *)arg2, comm,
1781 sizeof(comm)))
1782 return -EFAULT;
1783 return 0;
1784 case PR_GET_ENDIAN:
1785 error = GET_ENDIAN(me, arg2);
1786 break;
1787 case PR_SET_ENDIAN:
1788 error = SET_ENDIAN(me, arg2);
1789 break;
1790
1791 case PR_GET_SECCOMP:
1792 error = prctl_get_seccomp();
1793 break;
1794 case PR_SET_SECCOMP:
1795 error = prctl_set_seccomp(arg2);
1796 break;
1797 case PR_GET_TSC:
1798 error = GET_TSC_CTL(arg2);
1799 break;
1800 case PR_SET_TSC:
1801 error = SET_TSC_CTL(arg2);
1802 break;
1803 case PR_GET_TIMERSLACK:
1804 error = current->timer_slack_ns;
1805 break;
1806 case PR_SET_TIMERSLACK:
1807 if (arg2 <= 0)
1808 current->timer_slack_ns =
1809 current->default_timer_slack_ns;
1810 else
1811 current->timer_slack_ns = arg2;
1812 error = 0;
1813 break;
1814 default:
1815 error = -EINVAL;
1816 break;
1817 }
1818 return error;
1819 }
1820
SYSCALL_DEFINE3(getcpu,unsigned __user *,cpup,unsigned __user *,nodep,struct getcpu_cache __user *,unused)1821 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1822 struct getcpu_cache __user *, unused)
1823 {
1824 int err = 0;
1825 int cpu = raw_smp_processor_id();
1826 if (cpup)
1827 err |= put_user(cpu, cpup);
1828 if (nodep)
1829 err |= put_user(cpu_to_node(cpu), nodep);
1830 return err ? -EFAULT : 0;
1831 }
1832
1833 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1834
argv_cleanup(char ** argv,char ** envp)1835 static void argv_cleanup(char **argv, char **envp)
1836 {
1837 argv_free(argv);
1838 }
1839
1840 /**
1841 * orderly_poweroff - Trigger an orderly system poweroff
1842 * @force: force poweroff if command execution fails
1843 *
1844 * This may be called from any context to trigger a system shutdown.
1845 * If the orderly shutdown fails, it will force an immediate shutdown.
1846 */
orderly_poweroff(bool force)1847 int orderly_poweroff(bool force)
1848 {
1849 int argc;
1850 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1851 static char *envp[] = {
1852 "HOME=/",
1853 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1854 NULL
1855 };
1856 int ret = -ENOMEM;
1857 struct subprocess_info *info;
1858
1859 if (argv == NULL) {
1860 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1861 __func__, poweroff_cmd);
1862 goto out;
1863 }
1864
1865 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1866 if (info == NULL) {
1867 argv_free(argv);
1868 goto out;
1869 }
1870
1871 call_usermodehelper_setcleanup(info, argv_cleanup);
1872
1873 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1874
1875 out:
1876 if (ret && force) {
1877 printk(KERN_WARNING "Failed to start orderly shutdown: "
1878 "forcing the issue\n");
1879
1880 /* I guess this should try to kick off some daemon to
1881 sync and poweroff asap. Or not even bother syncing
1882 if we're doing an emergency shutdown? */
1883 emergency_sync();
1884 kernel_power_off();
1885 }
1886
1887 return ret;
1888 }
1889 EXPORT_SYMBOL_GPL(orderly_poweroff);
1890