4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/module.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>
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>
37 #include <linux/compat.h>
38 #include <linux/syscalls.h>
39 #include <linux/kprobes.h>
40 #include <linux/user_namespace.h>
42 #include <asm/uaccess.h>
44 #include <asm/unistd.h>
46 #ifndef SET_UNALIGN_CTL
47 # define SET_UNALIGN_CTL(a,b) (-EINVAL)
49 #ifndef GET_UNALIGN_CTL
50 # define GET_UNALIGN_CTL(a,b) (-EINVAL)
53 # define SET_FPEMU_CTL(a,b) (-EINVAL)
56 # define GET_FPEMU_CTL(a,b) (-EINVAL)
59 # define SET_FPEXC_CTL(a,b) (-EINVAL)
62 # define GET_FPEXC_CTL(a,b) (-EINVAL)
65 # define GET_ENDIAN(a,b) (-EINVAL)
68 # define SET_ENDIAN(a,b) (-EINVAL)
71 # define GET_TSC_CTL(a) (-EINVAL)
74 # define SET_TSC_CTL(a) (-EINVAL)
78 * this is where the system-wide overflow UID and GID are defined, for
79 * architectures that now have 32-bit UID/GID but didn't in the past
82 int overflowuid = DEFAULT_OVERFLOWUID;
83 int overflowgid = DEFAULT_OVERFLOWGID;
86 EXPORT_SYMBOL(overflowuid);
87 EXPORT_SYMBOL(overflowgid);
91 * the same as above, but for filesystems which can only store a 16-bit
92 * UID and GID. as such, this is needed on all architectures
95 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
96 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
98 EXPORT_SYMBOL(fs_overflowuid);
99 EXPORT_SYMBOL(fs_overflowgid);
102 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
107 EXPORT_SYMBOL(cad_pid);
110 * If set, this is used for preparing the system to power off.
113 void (*pm_power_off_prepare)(void);
115 static int set_one_prio(struct task_struct *p, int niceval, int error)
117 uid_t euid = current_euid();
120 if (p->cred->uid != euid &&
121 p->cred->euid != euid &&
122 !capable(CAP_SYS_NICE)) {
126 if (niceval < task_nice(p) && !can_nice(p, niceval)) {
130 no_nice = security_task_setnice(p, niceval);
137 set_user_nice(p, niceval);
142 asmlinkage long sys_setpriority(int which, int who, int niceval)
144 struct task_struct *g, *p;
145 struct user_struct *user;
146 const struct cred *cred = current_cred();
150 if (which > PRIO_USER || which < PRIO_PROCESS)
153 /* normalize: avoid signed division (rounding problems) */
160 read_lock(&tasklist_lock);
164 p = find_task_by_vpid(who);
168 error = set_one_prio(p, niceval, error);
172 pgrp = find_vpid(who);
174 pgrp = task_pgrp(current);
175 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
176 error = set_one_prio(p, niceval, error);
177 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
183 else if ((who != cred->uid) &&
184 !(user = find_user(who)))
185 goto out_unlock; /* No processes for this user */
188 if (__task_cred(p)->uid == who)
189 error = set_one_prio(p, niceval, error);
190 while_each_thread(g, p);
191 if (who != cred->uid)
192 free_uid(user); /* For find_user() */
196 read_unlock(&tasklist_lock);
202 * Ugh. To avoid negative return values, "getpriority()" will
203 * not return the normal nice-value, but a negated value that
204 * has been offset by 20 (ie it returns 40..1 instead of -20..19)
205 * to stay compatible.
207 asmlinkage long sys_getpriority(int which, int who)
209 struct task_struct *g, *p;
210 struct user_struct *user;
211 const struct cred *cred = current_cred();
212 long niceval, retval = -ESRCH;
215 if (which > PRIO_USER || which < PRIO_PROCESS)
218 read_lock(&tasklist_lock);
222 p = find_task_by_vpid(who);
226 niceval = 20 - task_nice(p);
227 if (niceval > retval)
233 pgrp = find_vpid(who);
235 pgrp = task_pgrp(current);
236 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
237 niceval = 20 - task_nice(p);
238 if (niceval > retval)
240 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
243 user = (struct user_struct *) cred->user;
246 else if ((who != cred->uid) &&
247 !(user = find_user(who)))
248 goto out_unlock; /* No processes for this user */
251 if (__task_cred(p)->uid == who) {
252 niceval = 20 - task_nice(p);
253 if (niceval > retval)
256 while_each_thread(g, p);
257 if (who != cred->uid)
258 free_uid(user); /* for find_user() */
262 read_unlock(&tasklist_lock);
268 * emergency_restart - reboot the system
270 * Without shutting down any hardware or taking any locks
271 * reboot the system. This is called when we know we are in
272 * trouble so this is our best effort to reboot. This is
273 * safe to call in interrupt context.
275 void emergency_restart(void)
277 machine_emergency_restart();
279 EXPORT_SYMBOL_GPL(emergency_restart);
281 void kernel_restart_prepare(char *cmd)
283 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
284 system_state = SYSTEM_RESTART;
290 * kernel_restart - reboot the system
291 * @cmd: pointer to buffer containing command to execute for restart
294 * Shutdown everything and perform a clean reboot.
295 * This is not safe to call in interrupt context.
297 void kernel_restart(char *cmd)
299 kernel_restart_prepare(cmd);
301 printk(KERN_EMERG "Restarting system.\n");
303 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
304 machine_restart(cmd);
306 EXPORT_SYMBOL_GPL(kernel_restart);
308 static void kernel_shutdown_prepare(enum system_states state)
310 blocking_notifier_call_chain(&reboot_notifier_list,
311 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
312 system_state = state;
316 * kernel_halt - halt the system
318 * Shutdown everything and perform a clean system halt.
320 void kernel_halt(void)
322 kernel_shutdown_prepare(SYSTEM_HALT);
324 printk(KERN_EMERG "System halted.\n");
328 EXPORT_SYMBOL_GPL(kernel_halt);
331 * kernel_power_off - power_off the system
333 * Shutdown everything and perform a clean system power_off.
335 void kernel_power_off(void)
337 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
338 if (pm_power_off_prepare)
339 pm_power_off_prepare();
340 disable_nonboot_cpus();
342 printk(KERN_EMERG "Power down.\n");
345 EXPORT_SYMBOL_GPL(kernel_power_off);
347 * Reboot system call: for obvious reasons only root may call it,
348 * and even root needs to set up some magic numbers in the registers
349 * so that some mistake won't make this reboot the whole machine.
350 * You can also set the meaning of the ctrl-alt-del-key here.
352 * reboot doesn't sync: do that yourself before calling this.
354 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
358 /* We only trust the superuser with rebooting the system. */
359 if (!capable(CAP_SYS_BOOT))
362 /* For safety, we require "magic" arguments. */
363 if (magic1 != LINUX_REBOOT_MAGIC1 ||
364 (magic2 != LINUX_REBOOT_MAGIC2 &&
365 magic2 != LINUX_REBOOT_MAGIC2A &&
366 magic2 != LINUX_REBOOT_MAGIC2B &&
367 magic2 != LINUX_REBOOT_MAGIC2C))
370 /* Instead of trying to make the power_off code look like
371 * halt when pm_power_off is not set do it the easy way.
373 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
374 cmd = LINUX_REBOOT_CMD_HALT;
378 case LINUX_REBOOT_CMD_RESTART:
379 kernel_restart(NULL);
382 case LINUX_REBOOT_CMD_CAD_ON:
386 case LINUX_REBOOT_CMD_CAD_OFF:
390 case LINUX_REBOOT_CMD_HALT:
396 case LINUX_REBOOT_CMD_POWER_OFF:
402 case LINUX_REBOOT_CMD_RESTART2:
403 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
407 buffer[sizeof(buffer) - 1] = '\0';
409 kernel_restart(buffer);
413 case LINUX_REBOOT_CMD_KEXEC:
416 ret = kernel_kexec();
422 #ifdef CONFIG_HIBERNATION
423 case LINUX_REBOOT_CMD_SW_SUSPEND:
425 int ret = hibernate();
439 static void deferred_cad(struct work_struct *dummy)
441 kernel_restart(NULL);
445 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
446 * As it's called within an interrupt, it may NOT sync: the only choice
447 * is whether to reboot at once, or just ignore the ctrl-alt-del.
449 void ctrl_alt_del(void)
451 static DECLARE_WORK(cad_work, deferred_cad);
454 schedule_work(&cad_work);
456 kill_cad_pid(SIGINT, 1);
460 * Unprivileged users may change the real gid to the effective gid
461 * or vice versa. (BSD-style)
463 * If you set the real gid at all, or set the effective gid to a value not
464 * equal to the real gid, then the saved gid is set to the new effective gid.
466 * This makes it possible for a setgid program to completely drop its
467 * privileges, which is often a useful assertion to make when you are doing
468 * a security audit over a program.
470 * The general idea is that a program which uses just setregid() will be
471 * 100% compatible with BSD. A program which uses just setgid() will be
472 * 100% compatible with POSIX with saved IDs.
474 * SMP: There are not races, the GIDs are checked only by filesystem
475 * operations (as far as semantic preservation is concerned).
477 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
479 struct cred *cred = current->cred;
480 int old_rgid = cred->gid;
481 int old_egid = cred->egid;
482 int new_rgid = old_rgid;
483 int new_egid = old_egid;
486 retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
490 if (rgid != (gid_t) -1) {
491 if ((old_rgid == rgid) ||
492 (cred->egid == rgid) ||
498 if (egid != (gid_t) -1) {
499 if ((old_rgid == egid) ||
500 (cred->egid == egid) ||
501 (cred->sgid == egid) ||
507 if (new_egid != old_egid) {
508 set_dumpable(current->mm, suid_dumpable);
511 if (rgid != (gid_t) -1 ||
512 (egid != (gid_t) -1 && egid != old_rgid))
513 cred->sgid = new_egid;
514 cred->fsgid = new_egid;
515 cred->egid = new_egid;
516 cred->gid = new_rgid;
517 key_fsgid_changed(current);
518 proc_id_connector(current, PROC_EVENT_GID);
523 * setgid() is implemented like SysV w/ SAVED_IDS
525 * SMP: Same implicit races as above.
527 asmlinkage long sys_setgid(gid_t gid)
529 struct cred *cred = current->cred;
530 int old_egid = cred->egid;
533 retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
537 if (capable(CAP_SETGID)) {
538 if (old_egid != gid) {
539 set_dumpable(current->mm, suid_dumpable);
542 cred->gid = cred->egid = cred->sgid = cred->fsgid = gid;
543 } else if ((gid == cred->gid) || (gid == cred->sgid)) {
544 if (old_egid != gid) {
545 set_dumpable(current->mm, suid_dumpable);
548 cred->egid = cred->fsgid = gid;
553 key_fsgid_changed(current);
554 proc_id_connector(current, PROC_EVENT_GID);
558 static int set_user(uid_t new_ruid, int dumpclear)
560 struct user_struct *new_user;
562 new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
566 if (atomic_read(&new_user->processes) >=
567 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
568 new_user != current->nsproxy->user_ns->root_user) {
573 switch_uid(new_user);
576 set_dumpable(current->mm, suid_dumpable);
579 current->cred->uid = new_ruid;
584 * Unprivileged users may change the real uid to the effective uid
585 * or vice versa. (BSD-style)
587 * If you set the real uid at all, or set the effective uid to a value not
588 * equal to the real uid, then the saved uid is set to the new effective uid.
590 * This makes it possible for a setuid program to completely drop its
591 * privileges, which is often a useful assertion to make when you are doing
592 * a security audit over a program.
594 * The general idea is that a program which uses just setreuid() will be
595 * 100% compatible with BSD. A program which uses just setuid() will be
596 * 100% compatible with POSIX with saved IDs.
598 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
600 struct cred *cred = current->cred;
601 int old_ruid, old_euid, old_suid, new_ruid, new_euid;
604 retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
608 new_ruid = old_ruid = cred->uid;
609 new_euid = old_euid = cred->euid;
610 old_suid = cred->suid;
612 if (ruid != (uid_t) -1) {
614 if ((old_ruid != ruid) &&
615 (cred->euid != ruid) &&
616 !capable(CAP_SETUID))
620 if (euid != (uid_t) -1) {
622 if ((old_ruid != euid) &&
623 (cred->euid != euid) &&
624 (cred->suid != euid) &&
625 !capable(CAP_SETUID))
629 if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
632 if (new_euid != old_euid) {
633 set_dumpable(current->mm, suid_dumpable);
636 cred->fsuid = cred->euid = new_euid;
637 if (ruid != (uid_t) -1 ||
638 (euid != (uid_t) -1 && euid != old_ruid))
639 cred->suid = cred->euid;
640 cred->fsuid = cred->euid;
642 key_fsuid_changed(current);
643 proc_id_connector(current, PROC_EVENT_UID);
645 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
651 * setuid() is implemented like SysV with SAVED_IDS
653 * Note that SAVED_ID's is deficient in that a setuid root program
654 * like sendmail, for example, cannot set its uid to be a normal
655 * user and then switch back, because if you're root, setuid() sets
656 * the saved uid too. If you don't like this, blame the bright people
657 * in the POSIX committee and/or USG. Note that the BSD-style setreuid()
658 * will allow a root program to temporarily drop privileges and be able to
659 * regain them by swapping the real and effective uid.
661 asmlinkage long sys_setuid(uid_t uid)
663 struct cred *cred = current->cred;
664 int old_euid = cred->euid;
665 int old_ruid, old_suid, new_suid;
668 retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
672 old_ruid = cred->uid;
673 old_suid = cred->suid;
676 if (capable(CAP_SETUID)) {
677 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
680 } else if ((uid != cred->uid) && (uid != new_suid))
683 if (old_euid != uid) {
684 set_dumpable(current->mm, suid_dumpable);
687 cred->fsuid = cred->euid = uid;
688 cred->suid = new_suid;
690 key_fsuid_changed(current);
691 proc_id_connector(current, PROC_EVENT_UID);
693 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
698 * This function implements a generic ability to update ruid, euid,
699 * and suid. This allows you to implement the 4.4 compatible seteuid().
701 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
703 struct cred *cred = current->cred;
704 int old_ruid = cred->uid;
705 int old_euid = cred->euid;
706 int old_suid = cred->suid;
709 retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
713 if (!capable(CAP_SETUID)) {
714 if ((ruid != (uid_t) -1) && (ruid != cred->uid) &&
715 (ruid != cred->euid) && (ruid != cred->suid))
717 if ((euid != (uid_t) -1) && (euid != cred->uid) &&
718 (euid != cred->euid) && (euid != cred->suid))
720 if ((suid != (uid_t) -1) && (suid != cred->uid) &&
721 (suid != cred->euid) && (suid != cred->suid))
724 if (ruid != (uid_t) -1) {
725 if (ruid != cred->uid &&
726 set_user(ruid, euid != cred->euid) < 0)
729 if (euid != (uid_t) -1) {
730 if (euid != cred->euid) {
731 set_dumpable(current->mm, suid_dumpable);
736 cred->fsuid = cred->euid;
737 if (suid != (uid_t) -1)
740 key_fsuid_changed(current);
741 proc_id_connector(current, PROC_EVENT_UID);
743 return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
746 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
748 const struct cred *cred = current_cred();
751 if (!(retval = put_user(cred->uid, ruid)) &&
752 !(retval = put_user(cred->euid, euid)))
753 retval = put_user(cred->suid, suid);
759 * Same as above, but for rgid, egid, sgid.
761 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
763 struct cred *cred = current->cred;
766 retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
770 if (!capable(CAP_SETGID)) {
771 if ((rgid != (gid_t) -1) && (rgid != cred->gid) &&
772 (rgid != cred->egid) && (rgid != cred->sgid))
774 if ((egid != (gid_t) -1) && (egid != cred->gid) &&
775 (egid != cred->egid) && (egid != cred->sgid))
777 if ((sgid != (gid_t) -1) && (sgid != cred->gid) &&
778 (sgid != cred->egid) && (sgid != cred->sgid))
781 if (egid != (gid_t) -1) {
782 if (egid != cred->egid) {
783 set_dumpable(current->mm, suid_dumpable);
788 cred->fsgid = cred->egid;
789 if (rgid != (gid_t) -1)
791 if (sgid != (gid_t) -1)
794 key_fsgid_changed(current);
795 proc_id_connector(current, PROC_EVENT_GID);
799 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
801 const struct cred *cred = current_cred();
804 if (!(retval = put_user(cred->gid, rgid)) &&
805 !(retval = put_user(cred->egid, egid)))
806 retval = put_user(cred->sgid, sgid);
813 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
814 * is used for "access()" and for the NFS daemon (letting nfsd stay at
815 * whatever uid it wants to). It normally shadows "euid", except when
816 * explicitly set by setfsuid() or for access..
818 asmlinkage long sys_setfsuid(uid_t uid)
820 struct cred *cred = current->cred;
823 old_fsuid = cred->fsuid;
824 if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
827 if (uid == cred->uid || uid == cred->euid ||
828 uid == cred->suid || uid == cred->fsuid ||
829 capable(CAP_SETUID)) {
830 if (uid != old_fsuid) {
831 set_dumpable(current->mm, suid_dumpable);
837 key_fsuid_changed(current);
838 proc_id_connector(current, PROC_EVENT_UID);
840 security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
846 * Samma på svenska..
848 asmlinkage long sys_setfsgid(gid_t gid)
850 struct cred *cred = current->cred;
853 old_fsgid = cred->fsgid;
854 if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
857 if (gid == cred->gid || gid == cred->egid ||
858 gid == cred->sgid || gid == cred->fsgid ||
859 capable(CAP_SETGID)) {
860 if (gid != old_fsgid) {
861 set_dumpable(current->mm, suid_dumpable);
865 key_fsgid_changed(current);
866 proc_id_connector(current, PROC_EVENT_GID);
871 void do_sys_times(struct tms *tms)
873 struct task_cputime cputime;
874 cputime_t cutime, cstime;
876 spin_lock_irq(¤t->sighand->siglock);
877 thread_group_cputime(current, &cputime);
878 cutime = current->signal->cutime;
879 cstime = current->signal->cstime;
880 spin_unlock_irq(¤t->sighand->siglock);
881 tms->tms_utime = cputime_to_clock_t(cputime.utime);
882 tms->tms_stime = cputime_to_clock_t(cputime.stime);
883 tms->tms_cutime = cputime_to_clock_t(cutime);
884 tms->tms_cstime = cputime_to_clock_t(cstime);
887 asmlinkage long sys_times(struct tms __user * tbuf)
893 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
896 return (long) jiffies_64_to_clock_t(get_jiffies_64());
900 * This needs some heavy checking ...
901 * I just haven't the stomach for it. I also don't fully
902 * understand sessions/pgrp etc. Let somebody who does explain it.
904 * OK, I think I have the protection semantics right.... this is really
905 * only important on a multi-user system anyway, to make sure one user
906 * can't send a signal to a process owned by another. -TYT, 12/12/91
908 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
911 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
913 struct task_struct *p;
914 struct task_struct *group_leader = current->group_leader;
919 pid = task_pid_vnr(group_leader);
925 /* From this point forward we keep holding onto the tasklist lock
926 * so that our parent does not change from under us. -DaveM
928 write_lock_irq(&tasklist_lock);
931 p = find_task_by_vpid(pid);
936 if (!thread_group_leader(p))
939 if (same_thread_group(p->real_parent, group_leader)) {
941 if (task_session(p) != task_session(group_leader))
948 if (p != group_leader)
953 if (p->signal->leader)
958 struct task_struct *g;
960 pgrp = find_vpid(pgid);
961 g = pid_task(pgrp, PIDTYPE_PGID);
962 if (!g || task_session(g) != task_session(group_leader))
966 err = security_task_setpgid(p, pgid);
970 if (task_pgrp(p) != pgrp) {
971 change_pid(p, PIDTYPE_PGID, pgrp);
972 set_task_pgrp(p, pid_nr(pgrp));
977 /* All paths lead to here, thus we are safe. -DaveM */
978 write_unlock_irq(&tasklist_lock);
982 asmlinkage long sys_getpgid(pid_t pid)
984 struct task_struct *p;
990 grp = task_pgrp(current);
993 p = find_task_by_vpid(pid);
1000 retval = security_task_getpgid(p);
1004 retval = pid_vnr(grp);
1010 #ifdef __ARCH_WANT_SYS_GETPGRP
1012 asmlinkage long sys_getpgrp(void)
1014 return sys_getpgid(0);
1019 asmlinkage long sys_getsid(pid_t pid)
1021 struct task_struct *p;
1027 sid = task_session(current);
1030 p = find_task_by_vpid(pid);
1033 sid = task_session(p);
1037 retval = security_task_getsid(p);
1041 retval = pid_vnr(sid);
1047 asmlinkage long sys_setsid(void)
1049 struct task_struct *group_leader = current->group_leader;
1050 struct pid *sid = task_pid(group_leader);
1051 pid_t session = pid_vnr(sid);
1054 write_lock_irq(&tasklist_lock);
1055 /* Fail if I am already a session leader */
1056 if (group_leader->signal->leader)
1059 /* Fail if a process group id already exists that equals the
1060 * proposed session id.
1062 if (pid_task(sid, PIDTYPE_PGID))
1065 group_leader->signal->leader = 1;
1066 __set_special_pids(sid);
1068 proc_clear_tty(group_leader);
1072 write_unlock_irq(&tasklist_lock);
1077 * Supplementary group IDs
1080 /* init to 2 - one for init_task, one to ensure it is never freed */
1081 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1083 struct group_info *groups_alloc(int gidsetsize)
1085 struct group_info *group_info;
1089 nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1090 /* Make sure we always allocate at least one indirect block pointer */
1091 nblocks = nblocks ? : 1;
1092 group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1095 group_info->ngroups = gidsetsize;
1096 group_info->nblocks = nblocks;
1097 atomic_set(&group_info->usage, 1);
1099 if (gidsetsize <= NGROUPS_SMALL)
1100 group_info->blocks[0] = group_info->small_block;
1102 for (i = 0; i < nblocks; i++) {
1104 b = (void *)__get_free_page(GFP_USER);
1106 goto out_undo_partial_alloc;
1107 group_info->blocks[i] = b;
1112 out_undo_partial_alloc:
1114 free_page((unsigned long)group_info->blocks[i]);
1120 EXPORT_SYMBOL(groups_alloc);
1122 void groups_free(struct group_info *group_info)
1124 if (group_info->blocks[0] != group_info->small_block) {
1126 for (i = 0; i < group_info->nblocks; i++)
1127 free_page((unsigned long)group_info->blocks[i]);
1132 EXPORT_SYMBOL(groups_free);
1134 /* export the group_info to a user-space array */
1135 static int groups_to_user(gid_t __user *grouplist,
1136 struct group_info *group_info)
1139 unsigned int count = group_info->ngroups;
1141 for (i = 0; i < group_info->nblocks; i++) {
1142 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1143 unsigned int len = cp_count * sizeof(*grouplist);
1145 if (copy_to_user(grouplist, group_info->blocks[i], len))
1148 grouplist += NGROUPS_PER_BLOCK;
1154 /* fill a group_info from a user-space array - it must be allocated already */
1155 static int groups_from_user(struct group_info *group_info,
1156 gid_t __user *grouplist)
1159 unsigned int count = group_info->ngroups;
1161 for (i = 0; i < group_info->nblocks; i++) {
1162 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1163 unsigned int len = cp_count * sizeof(*grouplist);
1165 if (copy_from_user(group_info->blocks[i], grouplist, len))
1168 grouplist += NGROUPS_PER_BLOCK;
1174 /* a simple Shell sort */
1175 static void groups_sort(struct group_info *group_info)
1177 int base, max, stride;
1178 int gidsetsize = group_info->ngroups;
1180 for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1185 max = gidsetsize - stride;
1186 for (base = 0; base < max; base++) {
1188 int right = left + stride;
1189 gid_t tmp = GROUP_AT(group_info, right);
1191 while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1192 GROUP_AT(group_info, right) =
1193 GROUP_AT(group_info, left);
1197 GROUP_AT(group_info, right) = tmp;
1203 /* a simple bsearch */
1204 int groups_search(const struct group_info *group_info, gid_t grp)
1206 unsigned int left, right;
1212 right = group_info->ngroups;
1213 while (left < right) {
1214 unsigned int mid = (left+right)/2;
1215 int cmp = grp - GROUP_AT(group_info, mid);
1227 * set_groups - Change a group subscription in a security record
1228 * @sec: The security record to alter
1229 * @group_info: The group list to impose
1231 * Validate a group subscription and, if valid, impose it upon a task security
1234 int set_groups(struct cred *cred, struct group_info *group_info)
1237 struct group_info *old_info;
1239 retval = security_task_setgroups(group_info);
1243 groups_sort(group_info);
1244 get_group_info(group_info);
1246 spin_lock(&cred->lock);
1247 old_info = cred->group_info;
1248 cred->group_info = group_info;
1249 spin_unlock(&cred->lock);
1251 put_group_info(old_info);
1255 EXPORT_SYMBOL(set_groups);
1258 * set_current_groups - Change current's group subscription
1259 * @group_info: The group list to impose
1261 * Validate a group subscription and, if valid, impose it upon current's task
1264 int set_current_groups(struct group_info *group_info)
1266 return set_groups(current->cred, group_info);
1269 EXPORT_SYMBOL(set_current_groups);
1271 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1273 const struct cred *cred = current_cred();
1279 /* no need to grab task_lock here; it cannot change */
1280 i = cred->group_info->ngroups;
1282 if (i > gidsetsize) {
1286 if (groups_to_user(grouplist, cred->group_info)) {
1296 * SMP: Our groups are copy-on-write. We can set them safely
1297 * without another task interfering.
1300 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1302 struct group_info *group_info;
1305 if (!capable(CAP_SETGID))
1307 if ((unsigned)gidsetsize > NGROUPS_MAX)
1310 group_info = groups_alloc(gidsetsize);
1313 retval = groups_from_user(group_info, grouplist);
1315 put_group_info(group_info);
1319 retval = set_current_groups(group_info);
1320 put_group_info(group_info);
1326 * Check whether we're fsgid/egid or in the supplemental group..
1328 int in_group_p(gid_t grp)
1330 const struct cred *cred = current_cred();
1333 if (grp != cred->fsgid)
1334 retval = groups_search(cred->group_info, grp);
1338 EXPORT_SYMBOL(in_group_p);
1340 int in_egroup_p(gid_t grp)
1342 const struct cred *cred = current_cred();
1345 if (grp != cred->egid)
1346 retval = groups_search(cred->group_info, grp);
1350 EXPORT_SYMBOL(in_egroup_p);
1352 DECLARE_RWSEM(uts_sem);
1354 asmlinkage long sys_newuname(struct new_utsname __user * name)
1358 down_read(&uts_sem);
1359 if (copy_to_user(name, utsname(), sizeof *name))
1365 asmlinkage long sys_sethostname(char __user *name, int len)
1368 char tmp[__NEW_UTS_LEN];
1370 if (!capable(CAP_SYS_ADMIN))
1372 if (len < 0 || len > __NEW_UTS_LEN)
1374 down_write(&uts_sem);
1376 if (!copy_from_user(tmp, name, len)) {
1377 struct new_utsname *u = utsname();
1379 memcpy(u->nodename, tmp, len);
1380 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1387 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1389 asmlinkage long sys_gethostname(char __user *name, int len)
1392 struct new_utsname *u;
1396 down_read(&uts_sem);
1398 i = 1 + strlen(u->nodename);
1402 if (copy_to_user(name, u->nodename, i))
1411 * Only setdomainname; getdomainname can be implemented by calling
1414 asmlinkage long sys_setdomainname(char __user *name, int len)
1417 char tmp[__NEW_UTS_LEN];
1419 if (!capable(CAP_SYS_ADMIN))
1421 if (len < 0 || len > __NEW_UTS_LEN)
1424 down_write(&uts_sem);
1426 if (!copy_from_user(tmp, name, len)) {
1427 struct new_utsname *u = utsname();
1429 memcpy(u->domainname, tmp, len);
1430 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1437 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1439 if (resource >= RLIM_NLIMITS)
1442 struct rlimit value;
1443 task_lock(current->group_leader);
1444 value = current->signal->rlim[resource];
1445 task_unlock(current->group_leader);
1446 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1450 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1453 * Back compatibility for getrlimit. Needed for some apps.
1456 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1459 if (resource >= RLIM_NLIMITS)
1462 task_lock(current->group_leader);
1463 x = current->signal->rlim[resource];
1464 task_unlock(current->group_leader);
1465 if (x.rlim_cur > 0x7FFFFFFF)
1466 x.rlim_cur = 0x7FFFFFFF;
1467 if (x.rlim_max > 0x7FFFFFFF)
1468 x.rlim_max = 0x7FFFFFFF;
1469 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1474 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1476 struct rlimit new_rlim, *old_rlim;
1479 if (resource >= RLIM_NLIMITS)
1481 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1483 old_rlim = current->signal->rlim + resource;
1484 if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1485 !capable(CAP_SYS_RESOURCE))
1488 if (resource == RLIMIT_NOFILE) {
1489 if (new_rlim.rlim_max == RLIM_INFINITY)
1490 new_rlim.rlim_max = sysctl_nr_open;
1491 if (new_rlim.rlim_cur == RLIM_INFINITY)
1492 new_rlim.rlim_cur = sysctl_nr_open;
1493 if (new_rlim.rlim_max > sysctl_nr_open)
1497 if (new_rlim.rlim_cur > new_rlim.rlim_max)
1500 retval = security_task_setrlimit(resource, &new_rlim);
1504 if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1506 * The caller is asking for an immediate RLIMIT_CPU
1507 * expiry. But we use the zero value to mean "it was
1508 * never set". So let's cheat and make it one second
1511 new_rlim.rlim_cur = 1;
1514 task_lock(current->group_leader);
1515 *old_rlim = new_rlim;
1516 task_unlock(current->group_leader);
1518 if (resource != RLIMIT_CPU)
1522 * RLIMIT_CPU handling. Note that the kernel fails to return an error
1523 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a
1524 * very long-standing error, and fixing it now risks breakage of
1525 * applications, so we live with it
1527 if (new_rlim.rlim_cur == RLIM_INFINITY)
1530 update_rlimit_cpu(new_rlim.rlim_cur);
1536 * It would make sense to put struct rusage in the task_struct,
1537 * except that would make the task_struct be *really big*. After
1538 * task_struct gets moved into malloc'ed memory, it would
1539 * make sense to do this. It will make moving the rest of the information
1540 * a lot simpler! (Which we're not doing right now because we're not
1541 * measuring them yet).
1543 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1544 * races with threads incrementing their own counters. But since word
1545 * reads are atomic, we either get new values or old values and we don't
1546 * care which for the sums. We always take the siglock to protect reading
1547 * the c* fields from p->signal from races with exit.c updating those
1548 * fields when reaping, so a sample either gets all the additions of a
1549 * given child after it's reaped, or none so this sample is before reaping.
1552 * We need to take the siglock for CHILDEREN, SELF and BOTH
1553 * for the cases current multithreaded, non-current single threaded
1554 * non-current multithreaded. Thread traversal is now safe with
1556 * Strictly speaking, we donot need to take the siglock if we are current and
1557 * single threaded, as no one else can take our signal_struct away, no one
1558 * else can reap the children to update signal->c* counters, and no one else
1559 * can race with the signal-> fields. If we do not take any lock, the
1560 * signal-> fields could be read out of order while another thread was just
1561 * exiting. So we should place a read memory barrier when we avoid the lock.
1562 * On the writer side, write memory barrier is implied in __exit_signal
1563 * as __exit_signal releases the siglock spinlock after updating the signal->
1564 * fields. But we don't do this yet to keep things simple.
1568 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1570 r->ru_nvcsw += t->nvcsw;
1571 r->ru_nivcsw += t->nivcsw;
1572 r->ru_minflt += t->min_flt;
1573 r->ru_majflt += t->maj_flt;
1574 r->ru_inblock += task_io_get_inblock(t);
1575 r->ru_oublock += task_io_get_oublock(t);
1578 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1580 struct task_struct *t;
1581 unsigned long flags;
1582 cputime_t utime, stime;
1583 struct task_cputime cputime;
1585 memset((char *) r, 0, sizeof *r);
1586 utime = stime = cputime_zero;
1588 if (who == RUSAGE_THREAD) {
1589 accumulate_thread_rusage(p, r);
1593 if (!lock_task_sighand(p, &flags))
1598 case RUSAGE_CHILDREN:
1599 utime = p->signal->cutime;
1600 stime = p->signal->cstime;
1601 r->ru_nvcsw = p->signal->cnvcsw;
1602 r->ru_nivcsw = p->signal->cnivcsw;
1603 r->ru_minflt = p->signal->cmin_flt;
1604 r->ru_majflt = p->signal->cmaj_flt;
1605 r->ru_inblock = p->signal->cinblock;
1606 r->ru_oublock = p->signal->coublock;
1608 if (who == RUSAGE_CHILDREN)
1612 thread_group_cputime(p, &cputime);
1613 utime = cputime_add(utime, cputime.utime);
1614 stime = cputime_add(stime, cputime.stime);
1615 r->ru_nvcsw += p->signal->nvcsw;
1616 r->ru_nivcsw += p->signal->nivcsw;
1617 r->ru_minflt += p->signal->min_flt;
1618 r->ru_majflt += p->signal->maj_flt;
1619 r->ru_inblock += p->signal->inblock;
1620 r->ru_oublock += p->signal->oublock;
1623 accumulate_thread_rusage(t, r);
1631 unlock_task_sighand(p, &flags);
1634 cputime_to_timeval(utime, &r->ru_utime);
1635 cputime_to_timeval(stime, &r->ru_stime);
1638 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1641 k_getrusage(p, who, &r);
1642 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1645 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1647 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1648 who != RUSAGE_THREAD)
1650 return getrusage(current, who, ru);
1653 asmlinkage long sys_umask(int mask)
1655 mask = xchg(¤t->fs->umask, mask & S_IRWXUGO);
1659 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1660 unsigned long arg4, unsigned long arg5)
1662 struct task_struct *me = current;
1663 unsigned char comm[sizeof(me->comm)];
1666 if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1670 case PR_SET_PDEATHSIG:
1671 if (!valid_signal(arg2)) {
1675 me->pdeath_signal = arg2;
1678 case PR_GET_PDEATHSIG:
1679 error = put_user(me->pdeath_signal, (int __user *)arg2);
1681 case PR_GET_DUMPABLE:
1682 error = get_dumpable(me->mm);
1684 case PR_SET_DUMPABLE:
1685 if (arg2 < 0 || arg2 > 1) {
1689 set_dumpable(me->mm, arg2);
1693 case PR_SET_UNALIGN:
1694 error = SET_UNALIGN_CTL(me, arg2);
1696 case PR_GET_UNALIGN:
1697 error = GET_UNALIGN_CTL(me, arg2);
1700 error = SET_FPEMU_CTL(me, arg2);
1703 error = GET_FPEMU_CTL(me, arg2);
1706 error = SET_FPEXC_CTL(me, arg2);
1709 error = GET_FPEXC_CTL(me, arg2);
1712 error = PR_TIMING_STATISTICAL;
1715 if (arg2 != PR_TIMING_STATISTICAL)
1722 comm[sizeof(me->comm)-1] = 0;
1723 if (strncpy_from_user(comm, (char __user *)arg2,
1724 sizeof(me->comm) - 1) < 0)
1726 set_task_comm(me, comm);
1729 get_task_comm(comm, me);
1730 if (copy_to_user((char __user *)arg2, comm,
1735 error = GET_ENDIAN(me, arg2);
1738 error = SET_ENDIAN(me, arg2);
1741 case PR_GET_SECCOMP:
1742 error = prctl_get_seccomp();
1744 case PR_SET_SECCOMP:
1745 error = prctl_set_seccomp(arg2);
1748 error = GET_TSC_CTL(arg2);
1751 error = SET_TSC_CTL(arg2);
1753 case PR_GET_TIMERSLACK:
1754 error = current->timer_slack_ns;
1756 case PR_SET_TIMERSLACK:
1758 current->timer_slack_ns =
1759 current->default_timer_slack_ns;
1761 current->timer_slack_ns = arg2;
1771 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1772 struct getcpu_cache __user *unused)
1775 int cpu = raw_smp_processor_id();
1777 err |= put_user(cpu, cpup);
1779 err |= put_user(cpu_to_node(cpu), nodep);
1780 return err ? -EFAULT : 0;
1783 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1785 static void argv_cleanup(char **argv, char **envp)
1791 * orderly_poweroff - Trigger an orderly system poweroff
1792 * @force: force poweroff if command execution fails
1794 * This may be called from any context to trigger a system shutdown.
1795 * If the orderly shutdown fails, it will force an immediate shutdown.
1797 int orderly_poweroff(bool force)
1800 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1801 static char *envp[] = {
1803 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1807 struct subprocess_info *info;
1810 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1811 __func__, poweroff_cmd);
1815 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1821 call_usermodehelper_setcleanup(info, argv_cleanup);
1823 ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1827 printk(KERN_WARNING "Failed to start orderly shutdown: "
1828 "forcing the issue\n");
1830 /* I guess this should try to kick off some daemon to
1831 sync and poweroff asap. Or not even bother syncing
1832 if we're doing an emergency shutdown? */
1839 EXPORT_SYMBOL_GPL(orderly_poweroff);