Add build option to to set the default panic timeout.
[linux-2.6.git] / kernel / sys.c
1 /*
2  *  linux/kernel/sys.c
3  *
4  *  Copyright (C) 1991, 1992  Linus Torvalds
5  */
6
7 #include <linux/module.h>
8 #include <linux/mm.h>
9 #include <linux/utsname.h>
10 #include <linux/mman.h>
11 #include <linux/reboot.h>
12 #include <linux/prctl.h>
13 #include <linux/highuid.h>
14 #include <linux/fs.h>
15 #include <linux/perf_event.h>
16 #include <linux/resource.h>
17 #include <linux/kernel.h>
18 #include <linux/kexec.h>
19 #include <linux/workqueue.h>
20 #include <linux/capability.h>
21 #include <linux/device.h>
22 #include <linux/key.h>
23 #include <linux/times.h>
24 #include <linux/posix-timers.h>
25 #include <linux/security.h>
26 #include <linux/dcookies.h>
27 #include <linux/suspend.h>
28 #include <linux/tty.h>
29 #include <linux/signal.h>
30 #include <linux/cn_proc.h>
31 #include <linux/getcpu.h>
32 #include <linux/task_io_accounting_ops.h>
33 #include <linux/seccomp.h>
34 #include <linux/cpu.h>
35 #include <linux/personality.h>
36 #include <linux/ptrace.h>
37 #include <linux/fs_struct.h>
38 #include <linux/gfp.h>
39 #include <linux/syscore_ops.h>
40 #include <linux/version.h>
41 #include <linux/ctype.h>
42
43 #include <linux/compat.h>
44 #include <linux/syscalls.h>
45 #include <linux/kprobes.h>
46 #include <linux/user_namespace.h>
47
48 #include <linux/kmsg_dump.h>
49 /* Move somewhere else to avoid recompiling? */
50 #include <generated/utsrelease.h>
51
52 #include <asm/uaccess.h>
53 #include <asm/io.h>
54 #include <asm/unistd.h>
55
56 #ifndef SET_UNALIGN_CTL
57 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
58 #endif
59 #ifndef GET_UNALIGN_CTL
60 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
61 #endif
62 #ifndef SET_FPEMU_CTL
63 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
64 #endif
65 #ifndef GET_FPEMU_CTL
66 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
67 #endif
68 #ifndef SET_FPEXC_CTL
69 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
70 #endif
71 #ifndef GET_FPEXC_CTL
72 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
73 #endif
74 #ifndef GET_ENDIAN
75 # define GET_ENDIAN(a,b)        (-EINVAL)
76 #endif
77 #ifndef SET_ENDIAN
78 # define SET_ENDIAN(a,b)        (-EINVAL)
79 #endif
80 #ifndef GET_TSC_CTL
81 # define GET_TSC_CTL(a)         (-EINVAL)
82 #endif
83 #ifndef SET_TSC_CTL
84 # define SET_TSC_CTL(a)         (-EINVAL)
85 #endif
86
87 /*
88  * this is where the system-wide overflow UID and GID are defined, for
89  * architectures that now have 32-bit UID/GID but didn't in the past
90  */
91
92 int overflowuid = DEFAULT_OVERFLOWUID;
93 int overflowgid = DEFAULT_OVERFLOWGID;
94
95 #ifdef CONFIG_UID16
96 EXPORT_SYMBOL(overflowuid);
97 EXPORT_SYMBOL(overflowgid);
98 #endif
99
100 /*
101  * the same as above, but for filesystems which can only store a 16-bit
102  * UID and GID. as such, this is needed on all architectures
103  */
104
105 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
106 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
107
108 EXPORT_SYMBOL(fs_overflowuid);
109 EXPORT_SYMBOL(fs_overflowgid);
110
111 /*
112  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
113  */
114
115 int C_A_D = 1;
116 struct pid *cad_pid;
117 EXPORT_SYMBOL(cad_pid);
118
119 /*
120  * If set, this is used for preparing the system to power off.
121  */
122
123 void (*pm_power_off_prepare)(void);
124
125 /*
126  * Returns true if current's euid is same as p's uid or euid,
127  * or has CAP_SYS_NICE to p's user_ns.
128  *
129  * Called with rcu_read_lock, creds are safe
130  */
131 static bool set_one_prio_perm(struct task_struct *p)
132 {
133         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
134
135         if (pcred->user->user_ns == cred->user->user_ns &&
136             (pcred->uid  == cred->euid ||
137              pcred->euid == cred->euid))
138                 return true;
139         if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE))
140                 return true;
141         return false;
142 }
143
144 /*
145  * set the priority of a task
146  * - the caller must hold the RCU read lock
147  */
148 static int set_one_prio(struct task_struct *p, int niceval, int error)
149 {
150         int no_nice;
151
152         if (!set_one_prio_perm(p)) {
153                 error = -EPERM;
154                 goto out;
155         }
156         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
157                 error = -EACCES;
158                 goto out;
159         }
160         no_nice = security_task_setnice(p, niceval);
161         if (no_nice) {
162                 error = no_nice;
163                 goto out;
164         }
165         if (error == -ESRCH)
166                 error = 0;
167         set_user_nice(p, niceval);
168 out:
169         return error;
170 }
171
172 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
173 {
174         struct task_struct *g, *p;
175         struct user_struct *user;
176         const struct cred *cred = current_cred();
177         int error = -EINVAL;
178         struct pid *pgrp;
179
180         if (which > PRIO_USER || which < PRIO_PROCESS)
181                 goto out;
182
183         /* normalize: avoid signed division (rounding problems) */
184         error = -ESRCH;
185         if (niceval < -20)
186                 niceval = -20;
187         if (niceval > 19)
188                 niceval = 19;
189
190         rcu_read_lock();
191         read_lock(&tasklist_lock);
192         switch (which) {
193                 case PRIO_PROCESS:
194                         if (who)
195                                 p = find_task_by_vpid(who);
196                         else
197                                 p = current;
198                         if (p)
199                                 error = set_one_prio(p, niceval, error);
200                         break;
201                 case PRIO_PGRP:
202                         if (who)
203                                 pgrp = find_vpid(who);
204                         else
205                                 pgrp = task_pgrp(current);
206                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
207                                 error = set_one_prio(p, niceval, error);
208                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
209                         break;
210                 case PRIO_USER:
211                         user = (struct user_struct *) cred->user;
212                         if (!who)
213                                 who = cred->uid;
214                         else if ((who != cred->uid) &&
215                                  !(user = find_user(who)))
216                                 goto out_unlock;        /* No processes for this user */
217
218                         do_each_thread(g, p) {
219                                 if (__task_cred(p)->uid == who)
220                                         error = set_one_prio(p, niceval, error);
221                         } while_each_thread(g, p);
222                         if (who != 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
247         if (which > PRIO_USER || which < PRIO_PROCESS)
248                 return -EINVAL;
249
250         rcu_read_lock();
251         read_lock(&tasklist_lock);
252         switch (which) {
253                 case PRIO_PROCESS:
254                         if (who)
255                                 p = find_task_by_vpid(who);
256                         else
257                                 p = current;
258                         if (p) {
259                                 niceval = 20 - task_nice(p);
260                                 if (niceval > retval)
261                                         retval = niceval;
262                         }
263                         break;
264                 case PRIO_PGRP:
265                         if (who)
266                                 pgrp = find_vpid(who);
267                         else
268                                 pgrp = task_pgrp(current);
269                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
270                                 niceval = 20 - task_nice(p);
271                                 if (niceval > retval)
272                                         retval = niceval;
273                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
274                         break;
275                 case PRIO_USER:
276                         user = (struct user_struct *) cred->user;
277                         if (!who)
278                                 who = cred->uid;
279                         else if ((who != cred->uid) &&
280                                  !(user = find_user(who)))
281                                 goto out_unlock;        /* No processes for this user */
282
283                         do_each_thread(g, p) {
284                                 if (__task_cred(p)->uid == who) {
285                                         niceval = 20 - task_nice(p);
286                                         if (niceval > retval)
287                                                 retval = niceval;
288                                 }
289                         } while_each_thread(g, p);
290                         if (who != cred->uid)
291                                 free_uid(user);         /* for find_user() */
292                         break;
293         }
294 out_unlock:
295         read_unlock(&tasklist_lock);
296         rcu_read_unlock();
297
298         return retval;
299 }
300
301 /**
302  *      emergency_restart - reboot the system
303  *
304  *      Without shutting down any hardware or taking any locks
305  *      reboot the system.  This is called when we know we are in
306  *      trouble so this is our best effort to reboot.  This is
307  *      safe to call in interrupt context.
308  */
309 void emergency_restart(void)
310 {
311         kmsg_dump(KMSG_DUMP_EMERG);
312         machine_emergency_restart();
313 }
314 EXPORT_SYMBOL_GPL(emergency_restart);
315
316 void kernel_restart_prepare(char *cmd)
317 {
318         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
319         system_state = SYSTEM_RESTART;
320         usermodehelper_disable();
321         device_shutdown();
322         syscore_shutdown();
323 }
324
325 /**
326  *      register_reboot_notifier - Register function to be called at reboot time
327  *      @nb: Info about notifier function to be called
328  *
329  *      Registers a function with the list of functions
330  *      to be called at reboot time.
331  *
332  *      Currently always returns zero, as blocking_notifier_chain_register()
333  *      always returns zero.
334  */
335 int register_reboot_notifier(struct notifier_block *nb)
336 {
337         return blocking_notifier_chain_register(&reboot_notifier_list, nb);
338 }
339 EXPORT_SYMBOL(register_reboot_notifier);
340
341 /**
342  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
343  *      @nb: Hook to be unregistered
344  *
345  *      Unregisters a previously registered reboot
346  *      notifier function.
347  *
348  *      Returns zero on success, or %-ENOENT on failure.
349  */
350 int unregister_reboot_notifier(struct notifier_block *nb)
351 {
352         return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
353 }
354 EXPORT_SYMBOL(unregister_reboot_notifier);
355
356 /**
357  *      kernel_restart - reboot the system
358  *      @cmd: pointer to buffer containing command to execute for restart
359  *              or %NULL
360  *
361  *      Shutdown everything and perform a clean reboot.
362  *      This is not safe to call in interrupt context.
363  */
364 void kernel_restart(char *cmd)
365 {
366         kernel_restart_prepare(cmd);
367         if (!cmd)
368                 printk(KERN_EMERG "Restarting system.\n");
369         else
370                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
371         kmsg_dump(KMSG_DUMP_RESTART);
372         machine_restart(cmd);
373 }
374 EXPORT_SYMBOL_GPL(kernel_restart);
375
376 static void kernel_shutdown_prepare(enum system_states state)
377 {
378         blocking_notifier_call_chain(&reboot_notifier_list,
379                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
380         system_state = state;
381         usermodehelper_disable();
382         device_shutdown();
383 }
384 /**
385  *      kernel_halt - halt the system
386  *
387  *      Shutdown everything and perform a clean system halt.
388  */
389 void kernel_halt(void)
390 {
391         kernel_shutdown_prepare(SYSTEM_HALT);
392         syscore_shutdown();
393         printk(KERN_EMERG "System halted.\n");
394         kmsg_dump(KMSG_DUMP_HALT);
395         machine_halt();
396 }
397
398 EXPORT_SYMBOL_GPL(kernel_halt);
399
400 /**
401  *      kernel_power_off - power_off the system
402  *
403  *      Shutdown everything and perform a clean system power_off.
404  */
405 void kernel_power_off(void)
406 {
407         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
408         if (pm_power_off_prepare)
409                 pm_power_off_prepare();
410         disable_nonboot_cpus();
411         syscore_shutdown();
412         printk(KERN_EMERG "Power down.\n");
413         kmsg_dump(KMSG_DUMP_POWEROFF);
414         machine_power_off();
415 }
416 EXPORT_SYMBOL_GPL(kernel_power_off);
417
418 static DEFINE_MUTEX(reboot_mutex);
419
420 /*
421  * Reboot system call: for obvious reasons only root may call it,
422  * and even root needs to set up some magic numbers in the registers
423  * so that some mistake won't make this reboot the whole machine.
424  * You can also set the meaning of the ctrl-alt-del-key here.
425  *
426  * reboot doesn't sync: do that yourself before calling this.
427  */
428 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
429                 void __user *, arg)
430 {
431         char buffer[256];
432         int ret = 0;
433
434         /* We only trust the superuser with rebooting the system. */
435         if (!capable(CAP_SYS_BOOT))
436                 return -EPERM;
437
438         /* For safety, we require "magic" arguments. */
439         if (magic1 != LINUX_REBOOT_MAGIC1 ||
440             (magic2 != LINUX_REBOOT_MAGIC2 &&
441                         magic2 != LINUX_REBOOT_MAGIC2A &&
442                         magic2 != LINUX_REBOOT_MAGIC2B &&
443                         magic2 != LINUX_REBOOT_MAGIC2C))
444                 return -EINVAL;
445
446         /* Instead of trying to make the power_off code look like
447          * halt when pm_power_off is not set do it the easy way.
448          */
449         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
450                 cmd = LINUX_REBOOT_CMD_HALT;
451
452         mutex_lock(&reboot_mutex);
453         switch (cmd) {
454         case LINUX_REBOOT_CMD_RESTART:
455                 kernel_restart(NULL);
456                 break;
457
458         case LINUX_REBOOT_CMD_CAD_ON:
459                 C_A_D = 1;
460                 break;
461
462         case LINUX_REBOOT_CMD_CAD_OFF:
463                 C_A_D = 0;
464                 break;
465
466         case LINUX_REBOOT_CMD_HALT:
467                 kernel_halt();
468                 do_exit(0);
469                 panic("cannot halt");
470
471         case LINUX_REBOOT_CMD_POWER_OFF:
472                 kernel_power_off();
473                 do_exit(0);
474                 break;
475
476         case LINUX_REBOOT_CMD_RESTART2:
477                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
478                         ret = -EFAULT;
479                         break;
480                 }
481                 buffer[sizeof(buffer) - 1] = '\0';
482
483                 kernel_restart(buffer);
484                 break;
485
486 #ifdef CONFIG_KEXEC
487         case LINUX_REBOOT_CMD_KEXEC:
488                 ret = kernel_kexec();
489                 break;
490 #endif
491
492 #ifdef CONFIG_HIBERNATION
493         case LINUX_REBOOT_CMD_SW_SUSPEND:
494                 ret = hibernate();
495                 break;
496 #endif
497
498         default:
499                 ret = -EINVAL;
500                 break;
501         }
502         mutex_unlock(&reboot_mutex);
503         return ret;
504 }
505
506 static void deferred_cad(struct work_struct *dummy)
507 {
508         kernel_restart(NULL);
509 }
510
511 /*
512  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
513  * As it's called within an interrupt, it may NOT sync: the only choice
514  * is whether to reboot at once, or just ignore the ctrl-alt-del.
515  */
516 void ctrl_alt_del(void)
517 {
518         static DECLARE_WORK(cad_work, deferred_cad);
519
520         if (C_A_D)
521                 schedule_work(&cad_work);
522         else
523                 kill_cad_pid(SIGINT, 1);
524 }
525         
526 /*
527  * Unprivileged users may change the real gid to the effective gid
528  * or vice versa.  (BSD-style)
529  *
530  * If you set the real gid at all, or set the effective gid to a value not
531  * equal to the real gid, then the saved gid is set to the new effective gid.
532  *
533  * This makes it possible for a setgid program to completely drop its
534  * privileges, which is often a useful assertion to make when you are doing
535  * a security audit over a program.
536  *
537  * The general idea is that a program which uses just setregid() will be
538  * 100% compatible with BSD.  A program which uses just setgid() will be
539  * 100% compatible with POSIX with saved IDs. 
540  *
541  * SMP: There are not races, the GIDs are checked only by filesystem
542  *      operations (as far as semantic preservation is concerned).
543  */
544 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
545 {
546         const struct cred *old;
547         struct cred *new;
548         int retval;
549
550         new = prepare_creds();
551         if (!new)
552                 return -ENOMEM;
553         old = current_cred();
554
555         retval = -EPERM;
556         if (rgid != (gid_t) -1) {
557                 if (old->gid == rgid ||
558                     old->egid == rgid ||
559                     nsown_capable(CAP_SETGID))
560                         new->gid = rgid;
561                 else
562                         goto error;
563         }
564         if (egid != (gid_t) -1) {
565                 if (old->gid == egid ||
566                     old->egid == egid ||
567                     old->sgid == egid ||
568                     nsown_capable(CAP_SETGID))
569                         new->egid = egid;
570                 else
571                         goto error;
572         }
573
574         if (rgid != (gid_t) -1 ||
575             (egid != (gid_t) -1 && egid != old->gid))
576                 new->sgid = new->egid;
577         new->fsgid = new->egid;
578
579         return commit_creds(new);
580
581 error:
582         abort_creds(new);
583         return retval;
584 }
585
586 /*
587  * setgid() is implemented like SysV w/ SAVED_IDS 
588  *
589  * SMP: Same implicit races as above.
590  */
591 SYSCALL_DEFINE1(setgid, gid_t, gid)
592 {
593         const struct cred *old;
594         struct cred *new;
595         int retval;
596
597         new = prepare_creds();
598         if (!new)
599                 return -ENOMEM;
600         old = current_cred();
601
602         retval = -EPERM;
603         if (nsown_capable(CAP_SETGID))
604                 new->gid = new->egid = new->sgid = new->fsgid = gid;
605         else if (gid == old->gid || gid == old->sgid)
606                 new->egid = new->fsgid = gid;
607         else
608                 goto error;
609
610         return commit_creds(new);
611
612 error:
613         abort_creds(new);
614         return retval;
615 }
616
617 /*
618  * change the user struct in a credentials set to match the new UID
619  */
620 static int set_user(struct cred *new)
621 {
622         struct user_struct *new_user;
623
624         new_user = alloc_uid(current_user_ns(), new->uid);
625         if (!new_user)
626                 return -EAGAIN;
627
628         /*
629          * We don't fail in case of NPROC limit excess here because too many
630          * poorly written programs don't check set*uid() return code, assuming
631          * it never fails if called by root.  We may still enforce NPROC limit
632          * for programs doing set*uid()+execve() by harmlessly deferring the
633          * failure to the execve() stage.
634          */
635         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
636                         new_user != INIT_USER)
637                 current->flags |= PF_NPROC_EXCEEDED;
638         else
639                 current->flags &= ~PF_NPROC_EXCEEDED;
640
641         free_uid(new->user);
642         new->user = new_user;
643         return 0;
644 }
645
646 /*
647  * Unprivileged users may change the real uid to the effective uid
648  * or vice versa.  (BSD-style)
649  *
650  * If you set the real uid at all, or set the effective uid to a value not
651  * equal to the real uid, then the saved uid is set to the new effective uid.
652  *
653  * This makes it possible for a setuid program to completely drop its
654  * privileges, which is often a useful assertion to make when you are doing
655  * a security audit over a program.
656  *
657  * The general idea is that a program which uses just setreuid() will be
658  * 100% compatible with BSD.  A program which uses just setuid() will be
659  * 100% compatible with POSIX with saved IDs. 
660  */
661 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
662 {
663         const struct cred *old;
664         struct cred *new;
665         int retval;
666
667         new = prepare_creds();
668         if (!new)
669                 return -ENOMEM;
670         old = current_cred();
671
672         retval = -EPERM;
673         if (ruid != (uid_t) -1) {
674                 new->uid = ruid;
675                 if (old->uid != ruid &&
676                     old->euid != ruid &&
677                     !nsown_capable(CAP_SETUID))
678                         goto error;
679         }
680
681         if (euid != (uid_t) -1) {
682                 new->euid = euid;
683                 if (old->uid != euid &&
684                     old->euid != euid &&
685                     old->suid != euid &&
686                     !nsown_capable(CAP_SETUID))
687                         goto error;
688         }
689
690         if (new->uid != old->uid) {
691                 retval = set_user(new);
692                 if (retval < 0)
693                         goto error;
694         }
695         if (ruid != (uid_t) -1 ||
696             (euid != (uid_t) -1 && euid != old->uid))
697                 new->suid = new->euid;
698         new->fsuid = new->euid;
699
700         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
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  * setuid() is implemented like SysV with SAVED_IDS 
713  * 
714  * Note that SAVED_ID's is deficient in that a setuid root program
715  * like sendmail, for example, cannot set its uid to be a normal 
716  * user and then switch back, because if you're root, setuid() sets
717  * the saved uid too.  If you don't like this, blame the bright people
718  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
719  * will allow a root program to temporarily drop privileges and be able to
720  * regain them by swapping the real and effective uid.  
721  */
722 SYSCALL_DEFINE1(setuid, uid_t, uid)
723 {
724         const struct cred *old;
725         struct cred *new;
726         int retval;
727
728         new = prepare_creds();
729         if (!new)
730                 return -ENOMEM;
731         old = current_cred();
732
733         retval = -EPERM;
734         if (nsown_capable(CAP_SETUID)) {
735                 new->suid = new->uid = uid;
736                 if (uid != old->uid) {
737                         retval = set_user(new);
738                         if (retval < 0)
739                                 goto error;
740                 }
741         } else if (uid != old->uid && uid != new->suid) {
742                 goto error;
743         }
744
745         new->fsuid = new->euid = uid;
746
747         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
748         if (retval < 0)
749                 goto error;
750
751         return commit_creds(new);
752
753 error:
754         abort_creds(new);
755         return retval;
756 }
757
758
759 /*
760  * This function implements a generic ability to update ruid, euid,
761  * and suid.  This allows you to implement the 4.4 compatible seteuid().
762  */
763 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
764 {
765         const struct cred *old;
766         struct cred *new;
767         int retval;
768
769         new = prepare_creds();
770         if (!new)
771                 return -ENOMEM;
772
773         old = current_cred();
774
775         retval = -EPERM;
776         if (!nsown_capable(CAP_SETUID)) {
777                 if (ruid != (uid_t) -1 && ruid != old->uid &&
778                     ruid != old->euid  && ruid != old->suid)
779                         goto error;
780                 if (euid != (uid_t) -1 && euid != old->uid &&
781                     euid != old->euid  && euid != old->suid)
782                         goto error;
783                 if (suid != (uid_t) -1 && suid != old->uid &&
784                     suid != old->euid  && suid != old->suid)
785                         goto error;
786         }
787
788         if (ruid != (uid_t) -1) {
789                 new->uid = ruid;
790                 if (ruid != old->uid) {
791                         retval = set_user(new);
792                         if (retval < 0)
793                                 goto error;
794                 }
795         }
796         if (euid != (uid_t) -1)
797                 new->euid = euid;
798         if (suid != (uid_t) -1)
799                 new->suid = suid;
800         new->fsuid = new->euid;
801
802         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
803         if (retval < 0)
804                 goto error;
805
806         return commit_creds(new);
807
808 error:
809         abort_creds(new);
810         return retval;
811 }
812
813 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
814 {
815         const struct cred *cred = current_cred();
816         int retval;
817
818         if (!(retval   = put_user(cred->uid,  ruid)) &&
819             !(retval   = put_user(cred->euid, euid)))
820                 retval = put_user(cred->suid, suid);
821
822         return retval;
823 }
824
825 /*
826  * Same as above, but for rgid, egid, sgid.
827  */
828 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
829 {
830         const struct cred *old;
831         struct cred *new;
832         int retval;
833
834         new = prepare_creds();
835         if (!new)
836                 return -ENOMEM;
837         old = current_cred();
838
839         retval = -EPERM;
840         if (!nsown_capable(CAP_SETGID)) {
841                 if (rgid != (gid_t) -1 && rgid != old->gid &&
842                     rgid != old->egid  && rgid != old->sgid)
843                         goto error;
844                 if (egid != (gid_t) -1 && egid != old->gid &&
845                     egid != old->egid  && egid != old->sgid)
846                         goto error;
847                 if (sgid != (gid_t) -1 && sgid != old->gid &&
848                     sgid != old->egid  && sgid != old->sgid)
849                         goto error;
850         }
851
852         if (rgid != (gid_t) -1)
853                 new->gid = rgid;
854         if (egid != (gid_t) -1)
855                 new->egid = egid;
856         if (sgid != (gid_t) -1)
857                 new->sgid = sgid;
858         new->fsgid = new->egid;
859
860         return commit_creds(new);
861
862 error:
863         abort_creds(new);
864         return retval;
865 }
866
867 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
868 {
869         const struct cred *cred = current_cred();
870         int retval;
871
872         if (!(retval   = put_user(cred->gid,  rgid)) &&
873             !(retval   = put_user(cred->egid, egid)))
874                 retval = put_user(cred->sgid, sgid);
875
876         return retval;
877 }
878
879
880 /*
881  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
882  * is used for "access()" and for the NFS daemon (letting nfsd stay at
883  * whatever uid it wants to). It normally shadows "euid", except when
884  * explicitly set by setfsuid() or for access..
885  */
886 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
887 {
888         const struct cred *old;
889         struct cred *new;
890         uid_t old_fsuid;
891
892         new = prepare_creds();
893         if (!new)
894                 return current_fsuid();
895         old = current_cred();
896         old_fsuid = old->fsuid;
897
898         if (uid == old->uid  || uid == old->euid  ||
899             uid == old->suid || uid == old->fsuid ||
900             nsown_capable(CAP_SETUID)) {
901                 if (uid != old_fsuid) {
902                         new->fsuid = uid;
903                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
904                                 goto change_okay;
905                 }
906         }
907
908         abort_creds(new);
909         return old_fsuid;
910
911 change_okay:
912         commit_creds(new);
913         return old_fsuid;
914 }
915
916 /*
917  * Samma på svenska..
918  */
919 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
920 {
921         const struct cred *old;
922         struct cred *new;
923         gid_t old_fsgid;
924
925         new = prepare_creds();
926         if (!new)
927                 return current_fsgid();
928         old = current_cred();
929         old_fsgid = old->fsgid;
930
931         if (gid == old->gid  || gid == old->egid  ||
932             gid == old->sgid || gid == old->fsgid ||
933             nsown_capable(CAP_SETGID)) {
934                 if (gid != old_fsgid) {
935                         new->fsgid = gid;
936                         goto change_okay;
937                 }
938         }
939
940         abort_creds(new);
941         return old_fsgid;
942
943 change_okay:
944         commit_creds(new);
945         return old_fsgid;
946 }
947
948 void do_sys_times(struct tms *tms)
949 {
950         cputime_t tgutime, tgstime, cutime, cstime;
951
952         spin_lock_irq(&current->sighand->siglock);
953         thread_group_times(current, &tgutime, &tgstime);
954         cutime = current->signal->cutime;
955         cstime = current->signal->cstime;
956         spin_unlock_irq(&current->sighand->siglock);
957         tms->tms_utime = cputime_to_clock_t(tgutime);
958         tms->tms_stime = cputime_to_clock_t(tgstime);
959         tms->tms_cutime = cputime_to_clock_t(cutime);
960         tms->tms_cstime = cputime_to_clock_t(cstime);
961 }
962
963 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
964 {
965         if (tbuf) {
966                 struct tms tmp;
967
968                 do_sys_times(&tmp);
969                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
970                         return -EFAULT;
971         }
972         force_successful_syscall_return();
973         return (long) jiffies_64_to_clock_t(get_jiffies_64());
974 }
975
976 /*
977  * This needs some heavy checking ...
978  * I just haven't the stomach for it. I also don't fully
979  * understand sessions/pgrp etc. Let somebody who does explain it.
980  *
981  * OK, I think I have the protection semantics right.... this is really
982  * only important on a multi-user system anyway, to make sure one user
983  * can't send a signal to a process owned by another.  -TYT, 12/12/91
984  *
985  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
986  * LBT 04.03.94
987  */
988 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
989 {
990         struct task_struct *p;
991         struct task_struct *group_leader = current->group_leader;
992         struct pid *pgrp;
993         int err;
994
995         if (!pid)
996                 pid = task_pid_vnr(group_leader);
997         if (!pgid)
998                 pgid = pid;
999         if (pgid < 0)
1000                 return -EINVAL;
1001         rcu_read_lock();
1002
1003         /* From this point forward we keep holding onto the tasklist lock
1004          * so that our parent does not change from under us. -DaveM
1005          */
1006         write_lock_irq(&tasklist_lock);
1007
1008         err = -ESRCH;
1009         p = find_task_by_vpid(pid);
1010         if (!p)
1011                 goto out;
1012
1013         err = -EINVAL;
1014         if (!thread_group_leader(p))
1015                 goto out;
1016
1017         if (same_thread_group(p->real_parent, group_leader)) {
1018                 err = -EPERM;
1019                 if (task_session(p) != task_session(group_leader))
1020                         goto out;
1021                 err = -EACCES;
1022                 if (p->did_exec)
1023                         goto out;
1024         } else {
1025                 err = -ESRCH;
1026                 if (p != group_leader)
1027                         goto out;
1028         }
1029
1030         err = -EPERM;
1031         if (p->signal->leader)
1032                 goto out;
1033
1034         pgrp = task_pid(p);
1035         if (pgid != pid) {
1036                 struct task_struct *g;
1037
1038                 pgrp = find_vpid(pgid);
1039                 g = pid_task(pgrp, PIDTYPE_PGID);
1040                 if (!g || task_session(g) != task_session(group_leader))
1041                         goto out;
1042         }
1043
1044         err = security_task_setpgid(p, pgid);
1045         if (err)
1046                 goto out;
1047
1048         if (task_pgrp(p) != pgrp)
1049                 change_pid(p, PIDTYPE_PGID, pgrp);
1050
1051         err = 0;
1052 out:
1053         /* All paths lead to here, thus we are safe. -DaveM */
1054         write_unlock_irq(&tasklist_lock);
1055         rcu_read_unlock();
1056         return err;
1057 }
1058
1059 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1060 {
1061         struct task_struct *p;
1062         struct pid *grp;
1063         int retval;
1064
1065         rcu_read_lock();
1066         if (!pid)
1067                 grp = task_pgrp(current);
1068         else {
1069                 retval = -ESRCH;
1070                 p = find_task_by_vpid(pid);
1071                 if (!p)
1072                         goto out;
1073                 grp = task_pgrp(p);
1074                 if (!grp)
1075                         goto out;
1076
1077                 retval = security_task_getpgid(p);
1078                 if (retval)
1079                         goto out;
1080         }
1081         retval = pid_vnr(grp);
1082 out:
1083         rcu_read_unlock();
1084         return retval;
1085 }
1086
1087 #ifdef __ARCH_WANT_SYS_GETPGRP
1088
1089 SYSCALL_DEFINE0(getpgrp)
1090 {
1091         return sys_getpgid(0);
1092 }
1093
1094 #endif
1095
1096 SYSCALL_DEFINE1(getsid, pid_t, pid)
1097 {
1098         struct task_struct *p;
1099         struct pid *sid;
1100         int retval;
1101
1102         rcu_read_lock();
1103         if (!pid)
1104                 sid = task_session(current);
1105         else {
1106                 retval = -ESRCH;
1107                 p = find_task_by_vpid(pid);
1108                 if (!p)
1109                         goto out;
1110                 sid = task_session(p);
1111                 if (!sid)
1112                         goto out;
1113
1114                 retval = security_task_getsid(p);
1115                 if (retval)
1116                         goto out;
1117         }
1118         retval = pid_vnr(sid);
1119 out:
1120         rcu_read_unlock();
1121         return retval;
1122 }
1123
1124 SYSCALL_DEFINE0(setsid)
1125 {
1126         struct task_struct *group_leader = current->group_leader;
1127         struct pid *sid = task_pid(group_leader);
1128         pid_t session = pid_vnr(sid);
1129         int err = -EPERM;
1130
1131         write_lock_irq(&tasklist_lock);
1132         /* Fail if I am already a session leader */
1133         if (group_leader->signal->leader)
1134                 goto out;
1135
1136         /* Fail if a process group id already exists that equals the
1137          * proposed session id.
1138          */
1139         if (pid_task(sid, PIDTYPE_PGID))
1140                 goto out;
1141
1142         group_leader->signal->leader = 1;
1143         __set_special_pids(sid);
1144
1145         proc_clear_tty(group_leader);
1146
1147         err = session;
1148 out:
1149         write_unlock_irq(&tasklist_lock);
1150         if (err > 0) {
1151                 proc_sid_connector(group_leader);
1152                 sched_autogroup_create_attach(group_leader);
1153         }
1154         return err;
1155 }
1156
1157 DECLARE_RWSEM(uts_sem);
1158
1159 #ifdef COMPAT_UTS_MACHINE
1160 #define override_architecture(name) \
1161         (personality(current->personality) == PER_LINUX32 && \
1162          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1163                       sizeof(COMPAT_UTS_MACHINE)))
1164 #else
1165 #define override_architecture(name)     0
1166 #endif
1167
1168 /*
1169  * Work around broken programs that cannot handle "Linux 3.0".
1170  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1171  */
1172 static int override_release(char __user *release, int len)
1173 {
1174         int ret = 0;
1175         char buf[65];
1176
1177         if (current->personality & UNAME26) {
1178                 char *rest = UTS_RELEASE;
1179                 int ndots = 0;
1180                 unsigned v;
1181
1182                 while (*rest) {
1183                         if (*rest == '.' && ++ndots >= 3)
1184                                 break;
1185                         if (!isdigit(*rest) && *rest != '.')
1186                                 break;
1187                         rest++;
1188                 }
1189                 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1190                 snprintf(buf, len, "2.6.%u%s", v, rest);
1191                 ret = copy_to_user(release, buf, len);
1192         }
1193         return ret;
1194 }
1195
1196 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1197 {
1198         int errno = 0;
1199
1200         down_read(&uts_sem);
1201         if (copy_to_user(name, utsname(), sizeof *name))
1202                 errno = -EFAULT;
1203         up_read(&uts_sem);
1204
1205         if (!errno && override_release(name->release, sizeof(name->release)))
1206                 errno = -EFAULT;
1207         if (!errno && override_architecture(name))
1208                 errno = -EFAULT;
1209         return errno;
1210 }
1211
1212 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1213 /*
1214  * Old cruft
1215  */
1216 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1217 {
1218         int error = 0;
1219
1220         if (!name)
1221                 return -EFAULT;
1222
1223         down_read(&uts_sem);
1224         if (copy_to_user(name, utsname(), sizeof(*name)))
1225                 error = -EFAULT;
1226         up_read(&uts_sem);
1227
1228         if (!error && override_release(name->release, sizeof(name->release)))
1229                 error = -EFAULT;
1230         if (!error && override_architecture(name))
1231                 error = -EFAULT;
1232         return error;
1233 }
1234
1235 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1236 {
1237         int error;
1238
1239         if (!name)
1240                 return -EFAULT;
1241         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1242                 return -EFAULT;
1243
1244         down_read(&uts_sem);
1245         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1246                                __OLD_UTS_LEN);
1247         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1248         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1249                                 __OLD_UTS_LEN);
1250         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1251         error |= __copy_to_user(&name->release, &utsname()->release,
1252                                 __OLD_UTS_LEN);
1253         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1254         error |= __copy_to_user(&name->version, &utsname()->version,
1255                                 __OLD_UTS_LEN);
1256         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1257         error |= __copy_to_user(&name->machine, &utsname()->machine,
1258                                 __OLD_UTS_LEN);
1259         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1260         up_read(&uts_sem);
1261
1262         if (!error && override_architecture(name))
1263                 error = -EFAULT;
1264         if (!error && override_release(name->release, sizeof(name->release)))
1265                 error = -EFAULT;
1266         return error ? -EFAULT : 0;
1267 }
1268 #endif
1269
1270 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1271 {
1272         int errno;
1273         char tmp[__NEW_UTS_LEN];
1274
1275         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1276                 return -EPERM;
1277
1278         if (len < 0 || len > __NEW_UTS_LEN)
1279                 return -EINVAL;
1280         down_write(&uts_sem);
1281         errno = -EFAULT;
1282         if (!copy_from_user(tmp, name, len)) {
1283                 struct new_utsname *u = utsname();
1284
1285                 memcpy(u->nodename, tmp, len);
1286                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1287                 errno = 0;
1288         }
1289         up_write(&uts_sem);
1290         return errno;
1291 }
1292
1293 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1294
1295 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1296 {
1297         int i, errno;
1298         struct new_utsname *u;
1299
1300         if (len < 0)
1301                 return -EINVAL;
1302         down_read(&uts_sem);
1303         u = utsname();
1304         i = 1 + strlen(u->nodename);
1305         if (i > len)
1306                 i = len;
1307         errno = 0;
1308         if (copy_to_user(name, u->nodename, i))
1309                 errno = -EFAULT;
1310         up_read(&uts_sem);
1311         return errno;
1312 }
1313
1314 #endif
1315
1316 /*
1317  * Only setdomainname; getdomainname can be implemented by calling
1318  * uname()
1319  */
1320 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1321 {
1322         int errno;
1323         char tmp[__NEW_UTS_LEN];
1324
1325         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1326                 return -EPERM;
1327         if (len < 0 || len > __NEW_UTS_LEN)
1328                 return -EINVAL;
1329
1330         down_write(&uts_sem);
1331         errno = -EFAULT;
1332         if (!copy_from_user(tmp, name, len)) {
1333                 struct new_utsname *u = utsname();
1334
1335                 memcpy(u->domainname, tmp, len);
1336                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1337                 errno = 0;
1338         }
1339         up_write(&uts_sem);
1340         return errno;
1341 }
1342
1343 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1344 {
1345         struct rlimit value;
1346         int ret;
1347
1348         ret = do_prlimit(current, resource, NULL, &value);
1349         if (!ret)
1350                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1351
1352         return ret;
1353 }
1354
1355 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1356
1357 /*
1358  *      Back compatibility for getrlimit. Needed for some apps.
1359  */
1360  
1361 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1362                 struct rlimit __user *, rlim)
1363 {
1364         struct rlimit x;
1365         if (resource >= RLIM_NLIMITS)
1366                 return -EINVAL;
1367
1368         task_lock(current->group_leader);
1369         x = current->signal->rlim[resource];
1370         task_unlock(current->group_leader);
1371         if (x.rlim_cur > 0x7FFFFFFF)
1372                 x.rlim_cur = 0x7FFFFFFF;
1373         if (x.rlim_max > 0x7FFFFFFF)
1374                 x.rlim_max = 0x7FFFFFFF;
1375         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1376 }
1377
1378 #endif
1379
1380 static inline bool rlim64_is_infinity(__u64 rlim64)
1381 {
1382 #if BITS_PER_LONG < 64
1383         return rlim64 >= ULONG_MAX;
1384 #else
1385         return rlim64 == RLIM64_INFINITY;
1386 #endif
1387 }
1388
1389 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1390 {
1391         if (rlim->rlim_cur == RLIM_INFINITY)
1392                 rlim64->rlim_cur = RLIM64_INFINITY;
1393         else
1394                 rlim64->rlim_cur = rlim->rlim_cur;
1395         if (rlim->rlim_max == RLIM_INFINITY)
1396                 rlim64->rlim_max = RLIM64_INFINITY;
1397         else
1398                 rlim64->rlim_max = rlim->rlim_max;
1399 }
1400
1401 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1402 {
1403         if (rlim64_is_infinity(rlim64->rlim_cur))
1404                 rlim->rlim_cur = RLIM_INFINITY;
1405         else
1406                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1407         if (rlim64_is_infinity(rlim64->rlim_max))
1408                 rlim->rlim_max = RLIM_INFINITY;
1409         else
1410                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1411 }
1412
1413 /* make sure you are allowed to change @tsk limits before calling this */
1414 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1415                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1416 {
1417         struct rlimit *rlim;
1418         int retval = 0;
1419
1420         if (resource >= RLIM_NLIMITS)
1421                 return -EINVAL;
1422         if (new_rlim) {
1423                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1424                         return -EINVAL;
1425                 if (resource == RLIMIT_NOFILE &&
1426                                 new_rlim->rlim_max > sysctl_nr_open)
1427                         return -EPERM;
1428         }
1429
1430         /* protect tsk->signal and tsk->sighand from disappearing */
1431         read_lock(&tasklist_lock);
1432         if (!tsk->sighand) {
1433                 retval = -ESRCH;
1434                 goto out;
1435         }
1436
1437         rlim = tsk->signal->rlim + resource;
1438         task_lock(tsk->group_leader);
1439         if (new_rlim) {
1440                 /* Keep the capable check against init_user_ns until
1441                    cgroups can contain all limits */
1442                 if (new_rlim->rlim_max > rlim->rlim_max &&
1443                                 !capable(CAP_SYS_RESOURCE))
1444                         retval = -EPERM;
1445                 if (!retval)
1446                         retval = security_task_setrlimit(tsk->group_leader,
1447                                         resource, new_rlim);
1448                 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1449                         /*
1450                          * The caller is asking for an immediate RLIMIT_CPU
1451                          * expiry.  But we use the zero value to mean "it was
1452                          * never set".  So let's cheat and make it one second
1453                          * instead
1454                          */
1455                         new_rlim->rlim_cur = 1;
1456                 }
1457         }
1458         if (!retval) {
1459                 if (old_rlim)
1460                         *old_rlim = *rlim;
1461                 if (new_rlim)
1462                         *rlim = *new_rlim;
1463         }
1464         task_unlock(tsk->group_leader);
1465
1466         /*
1467          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1468          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1469          * very long-standing error, and fixing it now risks breakage of
1470          * applications, so we live with it
1471          */
1472          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1473                          new_rlim->rlim_cur != RLIM_INFINITY)
1474                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1475 out:
1476         read_unlock(&tasklist_lock);
1477         return retval;
1478 }
1479
1480 /* rcu lock must be held */
1481 static int check_prlimit_permission(struct task_struct *task)
1482 {
1483         const struct cred *cred = current_cred(), *tcred;
1484
1485         if (current == task)
1486                 return 0;
1487
1488         tcred = __task_cred(task);
1489         if (cred->user->user_ns == tcred->user->user_ns &&
1490             (cred->uid == tcred->euid &&
1491              cred->uid == tcred->suid &&
1492              cred->uid == tcred->uid  &&
1493              cred->gid == tcred->egid &&
1494              cred->gid == tcred->sgid &&
1495              cred->gid == tcred->gid))
1496                 return 0;
1497         if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE))
1498                 return 0;
1499
1500         return -EPERM;
1501 }
1502
1503 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1504                 const struct rlimit64 __user *, new_rlim,
1505                 struct rlimit64 __user *, old_rlim)
1506 {
1507         struct rlimit64 old64, new64;
1508         struct rlimit old, new;
1509         struct task_struct *tsk;
1510         int ret;
1511
1512         if (new_rlim) {
1513                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1514                         return -EFAULT;
1515                 rlim64_to_rlim(&new64, &new);
1516         }
1517
1518         rcu_read_lock();
1519         tsk = pid ? find_task_by_vpid(pid) : current;
1520         if (!tsk) {
1521                 rcu_read_unlock();
1522                 return -ESRCH;
1523         }
1524         ret = check_prlimit_permission(tsk);
1525         if (ret) {
1526                 rcu_read_unlock();
1527                 return ret;
1528         }
1529         get_task_struct(tsk);
1530         rcu_read_unlock();
1531
1532         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1533                         old_rlim ? &old : NULL);
1534
1535         if (!ret && old_rlim) {
1536                 rlim_to_rlim64(&old, &old64);
1537                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1538                         ret = -EFAULT;
1539         }
1540
1541         put_task_struct(tsk);
1542         return ret;
1543 }
1544
1545 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1546 {
1547         struct rlimit new_rlim;
1548
1549         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1550                 return -EFAULT;
1551         return do_prlimit(current, resource, &new_rlim, NULL);
1552 }
1553
1554 /*
1555  * It would make sense to put struct rusage in the task_struct,
1556  * except that would make the task_struct be *really big*.  After
1557  * task_struct gets moved into malloc'ed memory, it would
1558  * make sense to do this.  It will make moving the rest of the information
1559  * a lot simpler!  (Which we're not doing right now because we're not
1560  * measuring them yet).
1561  *
1562  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1563  * races with threads incrementing their own counters.  But since word
1564  * reads are atomic, we either get new values or old values and we don't
1565  * care which for the sums.  We always take the siglock to protect reading
1566  * the c* fields from p->signal from races with exit.c updating those
1567  * fields when reaping, so a sample either gets all the additions of a
1568  * given child after it's reaped, or none so this sample is before reaping.
1569  *
1570  * Locking:
1571  * We need to take the siglock for CHILDEREN, SELF and BOTH
1572  * for  the cases current multithreaded, non-current single threaded
1573  * non-current multithreaded.  Thread traversal is now safe with
1574  * the siglock held.
1575  * Strictly speaking, we donot need to take the siglock if we are current and
1576  * single threaded,  as no one else can take our signal_struct away, no one
1577  * else can  reap the  children to update signal->c* counters, and no one else
1578  * can race with the signal-> fields. If we do not take any lock, the
1579  * signal-> fields could be read out of order while another thread was just
1580  * exiting. So we should  place a read memory barrier when we avoid the lock.
1581  * On the writer side,  write memory barrier is implied in  __exit_signal
1582  * as __exit_signal releases  the siglock spinlock after updating the signal->
1583  * fields. But we don't do this yet to keep things simple.
1584  *
1585  */
1586
1587 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1588 {
1589         r->ru_nvcsw += t->nvcsw;
1590         r->ru_nivcsw += t->nivcsw;
1591         r->ru_minflt += t->min_flt;
1592         r->ru_majflt += t->maj_flt;
1593         r->ru_inblock += task_io_get_inblock(t);
1594         r->ru_oublock += task_io_get_oublock(t);
1595 }
1596
1597 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1598 {
1599         struct task_struct *t;
1600         unsigned long flags;
1601         cputime_t tgutime, tgstime, utime, stime;
1602         unsigned long maxrss = 0;
1603
1604         memset((char *) r, 0, sizeof *r);
1605         utime = stime = cputime_zero;
1606
1607         if (who == RUSAGE_THREAD) {
1608                 task_times(current, &utime, &stime);
1609                 accumulate_thread_rusage(p, r);
1610                 maxrss = p->signal->maxrss;
1611                 goto out;
1612         }
1613
1614         if (!lock_task_sighand(p, &flags))
1615                 return;
1616
1617         switch (who) {
1618                 case RUSAGE_BOTH:
1619                 case RUSAGE_CHILDREN:
1620                         utime = p->signal->cutime;
1621                         stime = p->signal->cstime;
1622                         r->ru_nvcsw = p->signal->cnvcsw;
1623                         r->ru_nivcsw = p->signal->cnivcsw;
1624                         r->ru_minflt = p->signal->cmin_flt;
1625                         r->ru_majflt = p->signal->cmaj_flt;
1626                         r->ru_inblock = p->signal->cinblock;
1627                         r->ru_oublock = p->signal->coublock;
1628                         maxrss = p->signal->cmaxrss;
1629
1630                         if (who == RUSAGE_CHILDREN)
1631                                 break;
1632
1633                 case RUSAGE_SELF:
1634                         thread_group_times(p, &tgutime, &tgstime);
1635                         utime = cputime_add(utime, tgutime);
1636                         stime = cputime_add(stime, tgstime);
1637                         r->ru_nvcsw += p->signal->nvcsw;
1638                         r->ru_nivcsw += p->signal->nivcsw;
1639                         r->ru_minflt += p->signal->min_flt;
1640                         r->ru_majflt += p->signal->maj_flt;
1641                         r->ru_inblock += p->signal->inblock;
1642                         r->ru_oublock += p->signal->oublock;
1643                         if (maxrss < p->signal->maxrss)
1644                                 maxrss = p->signal->maxrss;
1645                         t = p;
1646                         do {
1647                                 accumulate_thread_rusage(t, r);
1648                                 t = next_thread(t);
1649                         } while (t != p);
1650                         break;
1651
1652                 default:
1653                         BUG();
1654         }
1655         unlock_task_sighand(p, &flags);
1656
1657 out:
1658         cputime_to_timeval(utime, &r->ru_utime);
1659         cputime_to_timeval(stime, &r->ru_stime);
1660
1661         if (who != RUSAGE_CHILDREN) {
1662                 struct mm_struct *mm = get_task_mm(p);
1663                 if (mm) {
1664                         setmax_mm_hiwater_rss(&maxrss, mm);
1665                         mmput(mm);
1666                 }
1667         }
1668         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1669 }
1670
1671 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1672 {
1673         struct rusage r;
1674         k_getrusage(p, who, &r);
1675         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1676 }
1677
1678 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1679 {
1680         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1681             who != RUSAGE_THREAD)
1682                 return -EINVAL;
1683         return getrusage(current, who, ru);
1684 }
1685
1686 SYSCALL_DEFINE1(umask, int, mask)
1687 {
1688         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1689         return mask;
1690 }
1691
1692 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1693                 unsigned long, arg4, unsigned long, arg5)
1694 {
1695         struct task_struct *me = current;
1696         unsigned char comm[sizeof(me->comm)];
1697         long error;
1698
1699         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1700         if (error != -ENOSYS)
1701                 return error;
1702
1703         error = 0;
1704         switch (option) {
1705                 case PR_SET_PDEATHSIG:
1706                         if (!valid_signal(arg2)) {
1707                                 error = -EINVAL;
1708                                 break;
1709                         }
1710                         me->pdeath_signal = arg2;
1711                         error = 0;
1712                         break;
1713                 case PR_GET_PDEATHSIG:
1714                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1715                         break;
1716                 case PR_GET_DUMPABLE:
1717                         error = get_dumpable(me->mm);
1718                         break;
1719                 case PR_SET_DUMPABLE:
1720                         if (arg2 < 0 || arg2 > 1) {
1721                                 error = -EINVAL;
1722                                 break;
1723                         }
1724                         set_dumpable(me->mm, arg2);
1725                         error = 0;
1726                         break;
1727
1728                 case PR_SET_UNALIGN:
1729                         error = SET_UNALIGN_CTL(me, arg2);
1730                         break;
1731                 case PR_GET_UNALIGN:
1732                         error = GET_UNALIGN_CTL(me, arg2);
1733                         break;
1734                 case PR_SET_FPEMU:
1735                         error = SET_FPEMU_CTL(me, arg2);
1736                         break;
1737                 case PR_GET_FPEMU:
1738                         error = GET_FPEMU_CTL(me, arg2);
1739                         break;
1740                 case PR_SET_FPEXC:
1741                         error = SET_FPEXC_CTL(me, arg2);
1742                         break;
1743                 case PR_GET_FPEXC:
1744                         error = GET_FPEXC_CTL(me, arg2);
1745                         break;
1746                 case PR_GET_TIMING:
1747                         error = PR_TIMING_STATISTICAL;
1748                         break;
1749                 case PR_SET_TIMING:
1750                         if (arg2 != PR_TIMING_STATISTICAL)
1751                                 error = -EINVAL;
1752                         else
1753                                 error = 0;
1754                         break;
1755
1756                 case PR_SET_NAME:
1757                         comm[sizeof(me->comm)-1] = 0;
1758                         if (strncpy_from_user(comm, (char __user *)arg2,
1759                                               sizeof(me->comm) - 1) < 0)
1760                                 return -EFAULT;
1761                         set_task_comm(me, comm);
1762                         return 0;
1763                 case PR_GET_NAME:
1764                         get_task_comm(comm, me);
1765                         if (copy_to_user((char __user *)arg2, comm,
1766                                          sizeof(comm)))
1767                                 return -EFAULT;
1768                         return 0;
1769                 case PR_GET_ENDIAN:
1770                         error = GET_ENDIAN(me, arg2);
1771                         break;
1772                 case PR_SET_ENDIAN:
1773                         error = SET_ENDIAN(me, arg2);
1774                         break;
1775
1776                 case PR_GET_SECCOMP:
1777                         error = prctl_get_seccomp();
1778                         break;
1779                 case PR_SET_SECCOMP:
1780                         error = prctl_set_seccomp(arg2);
1781                         break;
1782                 case PR_GET_TSC:
1783                         error = GET_TSC_CTL(arg2);
1784                         break;
1785                 case PR_SET_TSC:
1786                         error = SET_TSC_CTL(arg2);
1787                         break;
1788                 case PR_TASK_PERF_EVENTS_DISABLE:
1789                         error = perf_event_task_disable();
1790                         break;
1791                 case PR_TASK_PERF_EVENTS_ENABLE:
1792                         error = perf_event_task_enable();
1793                         break;
1794                 case PR_GET_TIMERSLACK:
1795                         error = current->timer_slack_ns;
1796                         break;
1797                 case PR_SET_TIMERSLACK:
1798                         if (arg2 <= 0)
1799                                 current->timer_slack_ns =
1800                                         current->default_timer_slack_ns;
1801                         else
1802                                 current->timer_slack_ns = arg2;
1803                         error = 0;
1804                         break;
1805                 case PR_MCE_KILL:
1806                         if (arg4 | arg5)
1807                                 return -EINVAL;
1808                         switch (arg2) {
1809                         case PR_MCE_KILL_CLEAR:
1810                                 if (arg3 != 0)
1811                                         return -EINVAL;
1812                                 current->flags &= ~PF_MCE_PROCESS;
1813                                 break;
1814                         case PR_MCE_KILL_SET:
1815                                 current->flags |= PF_MCE_PROCESS;
1816                                 if (arg3 == PR_MCE_KILL_EARLY)
1817                                         current->flags |= PF_MCE_EARLY;
1818                                 else if (arg3 == PR_MCE_KILL_LATE)
1819                                         current->flags &= ~PF_MCE_EARLY;
1820                                 else if (arg3 == PR_MCE_KILL_DEFAULT)
1821                                         current->flags &=
1822                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1823                                 else
1824                                         return -EINVAL;
1825                                 break;
1826                         default:
1827                                 return -EINVAL;
1828                         }
1829                         error = 0;
1830                         break;
1831                 case PR_MCE_KILL_GET:
1832                         if (arg2 | arg3 | arg4 | arg5)
1833                                 return -EINVAL;
1834                         if (current->flags & PF_MCE_PROCESS)
1835                                 error = (current->flags & PF_MCE_EARLY) ?
1836                                         PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1837                         else
1838                                 error = PR_MCE_KILL_DEFAULT;
1839                         break;
1840                 default:
1841                         error = -EINVAL;
1842                         break;
1843         }
1844         return error;
1845 }
1846
1847 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1848                 struct getcpu_cache __user *, unused)
1849 {
1850         int err = 0;
1851         int cpu = raw_smp_processor_id();
1852         if (cpup)
1853                 err |= put_user(cpu, cpup);
1854         if (nodep)
1855                 err |= put_user(cpu_to_node(cpu), nodep);
1856         return err ? -EFAULT : 0;
1857 }
1858
1859 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1860
1861 static void argv_cleanup(struct subprocess_info *info)
1862 {
1863         argv_free(info->argv);
1864 }
1865
1866 /**
1867  * orderly_poweroff - Trigger an orderly system poweroff
1868  * @force: force poweroff if command execution fails
1869  *
1870  * This may be called from any context to trigger a system shutdown.
1871  * If the orderly shutdown fails, it will force an immediate shutdown.
1872  */
1873 int orderly_poweroff(bool force)
1874 {
1875         int argc;
1876         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1877         static char *envp[] = {
1878                 "HOME=/",
1879                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1880                 NULL
1881         };
1882         int ret = -ENOMEM;
1883         struct subprocess_info *info;
1884
1885         if (argv == NULL) {
1886                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1887                        __func__, poweroff_cmd);
1888                 goto out;
1889         }
1890
1891         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1892         if (info == NULL) {
1893                 argv_free(argv);
1894                 goto out;
1895         }
1896
1897         call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1898
1899         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1900
1901   out:
1902         if (ret && force) {
1903                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1904                        "forcing the issue\n");
1905
1906                 /* I guess this should try to kick off some daemon to
1907                    sync and poweroff asap.  Or not even bother syncing
1908                    if we're doing an emergency shutdown? */
1909                 emergency_sync();
1910                 kernel_power_off();
1911         }
1912
1913         return ret;
1914 }
1915 EXPORT_SYMBOL_GPL(orderly_poweroff);