Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/kernel/sys.c

  1 /*
  2  *  linux/kernel/sys.c
  3  *
  4  *  Copyright (C) 1991, 1992  Linus Torvalds
  5  */
  6 
  7 #include <linux/export.h>
  8 #include <linux/mm.h>
  9 #include <linux/utsname.h>
 10 #include <linux/mman.h>
 11 #include <linux/reboot.h>
 12 #include <linux/prctl.h>
 13 #include <linux/highuid.h>
 14 #include <linux/fs.h>
 15 #include <linux/kmod.h>
 16 #include <linux/perf_event.h>
 17 #include <linux/resource.h>
 18 #include <linux/kernel.h>
 19 #include <linux/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/file.h>
 39 #include <linux/mount.h>
 40 #include <linux/gfp.h>
 41 #include <linux/syscore_ops.h>
 42 #include <linux/version.h>
 43 #include <linux/ctype.h>
 44 
 45 #include <linux/compat.h>
 46 #include <linux/syscalls.h>
 47 #include <linux/kprobes.h>
 48 #include <linux/user_namespace.h>
 49 #include <linux/binfmts.h>
 50 
 51 #include <linux/sched.h>
 52 #include <linux/rcupdate.h>
 53 #include <linux/uidgid.h>
 54 #include <linux/cred.h>
 55 
 56 #include <linux/kmsg_dump.h>
 57 /* Move somewhere else to avoid recompiling? */
 58 #include <generated/utsrelease.h>
 59 
 60 #include <linux/uaccess.h>
 61 #include <asm/io.h>
 62 #include <asm/unistd.h>
 63 
 64 #ifndef SET_UNALIGN_CTL
 65 # define SET_UNALIGN_CTL(a, b)  (-EINVAL)
 66 #endif
 67 #ifndef GET_UNALIGN_CTL
 68 # define GET_UNALIGN_CTL(a, b)  (-EINVAL)
 69 #endif
 70 #ifndef SET_FPEMU_CTL
 71 # define SET_FPEMU_CTL(a, b)    (-EINVAL)
 72 #endif
 73 #ifndef GET_FPEMU_CTL
 74 # define GET_FPEMU_CTL(a, b)    (-EINVAL)
 75 #endif
 76 #ifndef SET_FPEXC_CTL
 77 # define SET_FPEXC_CTL(a, b)    (-EINVAL)
 78 #endif
 79 #ifndef GET_FPEXC_CTL
 80 # define GET_FPEXC_CTL(a, b)    (-EINVAL)
 81 #endif
 82 #ifndef GET_ENDIAN
 83 # define GET_ENDIAN(a, b)       (-EINVAL)
 84 #endif
 85 #ifndef SET_ENDIAN
 86 # define SET_ENDIAN(a, b)       (-EINVAL)
 87 #endif
 88 #ifndef GET_TSC_CTL
 89 # define GET_TSC_CTL(a)         (-EINVAL)
 90 #endif
 91 #ifndef SET_TSC_CTL
 92 # define SET_TSC_CTL(a)         (-EINVAL)
 93 #endif
 94 #ifndef MPX_ENABLE_MANAGEMENT
 95 # define MPX_ENABLE_MANAGEMENT()        (-EINVAL)
 96 #endif
 97 #ifndef MPX_DISABLE_MANAGEMENT
 98 # define MPX_DISABLE_MANAGEMENT()       (-EINVAL)
 99 #endif
100 #ifndef GET_FP_MODE
101 # define GET_FP_MODE(a)         (-EINVAL)
102 #endif
103 #ifndef SET_FP_MODE
104 # define SET_FP_MODE(a,b)       (-EINVAL)
105 #endif
106 
107 /*
108  * this is where the system-wide overflow UID and GID are defined, for
109  * architectures that now have 32-bit UID/GID but didn't in the past
110  */
111 
112 int overflowuid = DEFAULT_OVERFLOWUID;
113 int overflowgid = DEFAULT_OVERFLOWGID;
114 
115 EXPORT_SYMBOL(overflowuid);
116 EXPORT_SYMBOL(overflowgid);
117 
118 /*
119  * the same as above, but for filesystems which can only store a 16-bit
120  * UID and GID. as such, this is needed on all architectures
121  */
122 
123 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
124 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
125 
126 EXPORT_SYMBOL(fs_overflowuid);
127 EXPORT_SYMBOL(fs_overflowgid);
128 
129 /*
130  * Returns true if current's euid is same as p's uid or euid,
131  * or has CAP_SYS_NICE to p's user_ns.
132  *
133  * Called with rcu_read_lock, creds are safe
134  */
135 static bool set_one_prio_perm(struct task_struct *p)
136 {
137         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
138 
139         if (uid_eq(pcred->uid,  cred->euid) ||
140             uid_eq(pcred->euid, cred->euid))
141                 return true;
142         if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
143                 return true;
144         return false;
145 }
146 
147 /*
148  * set the priority of a task
149  * - the caller must hold the RCU read lock
150  */
151 static int set_one_prio(struct task_struct *p, int niceval, int error)
152 {
153         int no_nice;
154 
155         if (!set_one_prio_perm(p)) {
156                 error = -EPERM;
157                 goto out;
158         }
159         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
160                 error = -EACCES;
161                 goto out;
162         }
163         no_nice = security_task_setnice(p, niceval);
164         if (no_nice) {
165                 error = no_nice;
166                 goto out;
167         }
168         if (error == -ESRCH)
169                 error = 0;
170         set_user_nice(p, niceval);
171 out:
172         return error;
173 }
174 
175 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
176 {
177         struct task_struct *g, *p;
178         struct user_struct *user;
179         const struct cred *cred = current_cred();
180         int error = -EINVAL;
181         struct pid *pgrp;
182         kuid_t uid;
183 
184         if (which > PRIO_USER || which < PRIO_PROCESS)
185                 goto out;
186 
187         /* normalize: avoid signed division (rounding problems) */
188         error = -ESRCH;
189         if (niceval < MIN_NICE)
190                 niceval = MIN_NICE;
191         if (niceval > MAX_NICE)
192                 niceval = MAX_NICE;
193 
194         rcu_read_lock();
195         read_lock(&tasklist_lock);
196         switch (which) {
197         case PRIO_PROCESS:
198                 if (who)
199                         p = find_task_by_vpid(who);
200                 else
201                         p = current;
202                 if (p)
203                         error = set_one_prio(p, niceval, error);
204                 break;
205         case PRIO_PGRP:
206                 if (who)
207                         pgrp = find_vpid(who);
208                 else
209                         pgrp = task_pgrp(current);
210                 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
211                         error = set_one_prio(p, niceval, error);
212                 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
213                 break;
214         case PRIO_USER:
215                 uid = make_kuid(cred->user_ns, who);
216                 user = cred->user;
217                 if (!who)
218                         uid = cred->uid;
219                 else if (!uid_eq(uid, cred->uid)) {
220                         user = find_user(uid);
221                         if (!user)
222                                 goto out_unlock;        /* No processes for this user */
223                 }
224                 do_each_thread(g, p) {
225                         if (uid_eq(task_uid(p), uid) && task_pid_vnr(p))
226                                 error = set_one_prio(p, niceval, error);
227                 } while_each_thread(g, p);
228                 if (!uid_eq(uid, cred->uid))
229                         free_uid(user);         /* For find_user() */
230                 break;
231         }
232 out_unlock:
233         read_unlock(&tasklist_lock);
234         rcu_read_unlock();
235 out:
236         return error;
237 }
238 
239 /*
240  * Ugh. To avoid negative return values, "getpriority()" will
241  * not return the normal nice-value, but a negated value that
242  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
243  * to stay compatible.
244  */
245 SYSCALL_DEFINE2(getpriority, int, which, int, who)
246 {
247         struct task_struct *g, *p;
248         struct user_struct *user;
249         const struct cred *cred = current_cred();
250         long niceval, retval = -ESRCH;
251         struct pid *pgrp;
252         kuid_t uid;
253 
254         if (which > PRIO_USER || which < PRIO_PROCESS)
255                 return -EINVAL;
256 
257         rcu_read_lock();
258         read_lock(&tasklist_lock);
259         switch (which) {
260         case PRIO_PROCESS:
261                 if (who)
262                         p = find_task_by_vpid(who);
263                 else
264                         p = current;
265                 if (p) {
266                         niceval = nice_to_rlimit(task_nice(p));
267                         if (niceval > retval)
268                                 retval = niceval;
269                 }
270                 break;
271         case PRIO_PGRP:
272                 if (who)
273                         pgrp = find_vpid(who);
274                 else
275                         pgrp = task_pgrp(current);
276                 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
277                         niceval = nice_to_rlimit(task_nice(p));
278                         if (niceval > retval)
279                                 retval = niceval;
280                 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
281                 break;
282         case PRIO_USER:
283                 uid = make_kuid(cred->user_ns, who);
284                 user = cred->user;
285                 if (!who)
286                         uid = cred->uid;
287                 else if (!uid_eq(uid, cred->uid)) {
288                         user = find_user(uid);
289                         if (!user)
290                                 goto out_unlock;        /* No processes for this user */
291                 }
292                 do_each_thread(g, p) {
293                         if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) {
294                                 niceval = nice_to_rlimit(task_nice(p));
295                                 if (niceval > retval)
296                                         retval = niceval;
297                         }
298                 } while_each_thread(g, p);
299                 if (!uid_eq(uid, cred->uid))
300                         free_uid(user);         /* for find_user() */
301                 break;
302         }
303 out_unlock:
304         read_unlock(&tasklist_lock);
305         rcu_read_unlock();
306 
307         return retval;
308 }
309 
310 /*
311  * Unprivileged users may change the real gid to the effective gid
312  * or vice versa.  (BSD-style)
313  *
314  * If you set the real gid at all, or set the effective gid to a value not
315  * equal to the real gid, then the saved gid is set to the new effective gid.
316  *
317  * This makes it possible for a setgid program to completely drop its
318  * privileges, which is often a useful assertion to make when you are doing
319  * a security audit over a program.
320  *
321  * The general idea is that a program which uses just setregid() will be
322  * 100% compatible with BSD.  A program which uses just setgid() will be
323  * 100% compatible with POSIX with saved IDs.
324  *
325  * SMP: There are not races, the GIDs are checked only by filesystem
326  *      operations (as far as semantic preservation is concerned).
327  */
328 #ifdef CONFIG_MULTIUSER
329 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
330 {
331         struct user_namespace *ns = current_user_ns();
332         const struct cred *old;
333         struct cred *new;
334         int retval;
335         kgid_t krgid, kegid;
336 
337         krgid = make_kgid(ns, rgid);
338         kegid = make_kgid(ns, egid);
339 
340         if ((rgid != (gid_t) -1) && !gid_valid(krgid))
341                 return -EINVAL;
342         if ((egid != (gid_t) -1) && !gid_valid(kegid))
343                 return -EINVAL;
344 
345         new = prepare_creds();
346         if (!new)
347                 return -ENOMEM;
348         old = current_cred();
349 
350         retval = -EPERM;
351         if (rgid != (gid_t) -1) {
352                 if (gid_eq(old->gid, krgid) ||
353                     gid_eq(old->egid, krgid) ||
354                     ns_capable(old->user_ns, CAP_SETGID))
355                         new->gid = krgid;
356                 else
357                         goto error;
358         }
359         if (egid != (gid_t) -1) {
360                 if (gid_eq(old->gid, kegid) ||
361                     gid_eq(old->egid, kegid) ||
362                     gid_eq(old->sgid, kegid) ||
363                     ns_capable(old->user_ns, CAP_SETGID))
364                         new->egid = kegid;
365                 else
366                         goto error;
367         }
368 
369         if (rgid != (gid_t) -1 ||
370             (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
371                 new->sgid = new->egid;
372         new->fsgid = new->egid;
373 
374         return commit_creds(new);
375 
376 error:
377         abort_creds(new);
378         return retval;
379 }
380 
381 /*
382  * setgid() is implemented like SysV w/ SAVED_IDS
383  *
384  * SMP: Same implicit races as above.
385  */
386 SYSCALL_DEFINE1(setgid, gid_t, gid)
387 {
388         struct user_namespace *ns = current_user_ns();
389         const struct cred *old;
390         struct cred *new;
391         int retval;
392         kgid_t kgid;
393 
394         kgid = make_kgid(ns, gid);
395         if (!gid_valid(kgid))
396                 return -EINVAL;
397 
398         new = prepare_creds();
399         if (!new)
400                 return -ENOMEM;
401         old = current_cred();
402 
403         retval = -EPERM;
404         if (ns_capable(old->user_ns, CAP_SETGID))
405                 new->gid = new->egid = new->sgid = new->fsgid = kgid;
406         else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
407                 new->egid = new->fsgid = kgid;
408         else
409                 goto error;
410 
411         return commit_creds(new);
412 
413 error:
414         abort_creds(new);
415         return retval;
416 }
417 
418 /*
419  * change the user struct in a credentials set to match the new UID
420  */
421 static int set_user(struct cred *new)
422 {
423         struct user_struct *new_user;
424 
425         new_user = alloc_uid(new->uid);
426         if (!new_user)
427                 return -EAGAIN;
428 
429         /*
430          * We don't fail in case of NPROC limit excess here because too many
431          * poorly written programs don't check set*uid() return code, assuming
432          * it never fails if called by root.  We may still enforce NPROC limit
433          * for programs doing set*uid()+execve() by harmlessly deferring the
434          * failure to the execve() stage.
435          */
436         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
437                         new_user != INIT_USER)
438                 current->flags |= PF_NPROC_EXCEEDED;
439         else
440                 current->flags &= ~PF_NPROC_EXCEEDED;
441 
442         free_uid(new->user);
443         new->user = new_user;
444         return 0;
445 }
446 
447 /*
448  * Unprivileged users may change the real uid to the effective uid
449  * or vice versa.  (BSD-style)
450  *
451  * If you set the real uid at all, or set the effective uid to a value not
452  * equal to the real uid, then the saved uid is set to the new effective uid.
453  *
454  * This makes it possible for a setuid program to completely drop its
455  * privileges, which is often a useful assertion to make when you are doing
456  * a security audit over a program.
457  *
458  * The general idea is that a program which uses just setreuid() will be
459  * 100% compatible with BSD.  A program which uses just setuid() will be
460  * 100% compatible with POSIX with saved IDs.
461  */
462 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
463 {
464         struct user_namespace *ns = current_user_ns();
465         const struct cred *old;
466         struct cred *new;
467         int retval;
468         kuid_t kruid, keuid;
469 
470         kruid = make_kuid(ns, ruid);
471         keuid = make_kuid(ns, euid);
472 
473         if ((ruid != (uid_t) -1) && !uid_valid(kruid))
474                 return -EINVAL;
475         if ((euid != (uid_t) -1) && !uid_valid(keuid))
476                 return -EINVAL;
477 
478         new = prepare_creds();
479         if (!new)
480                 return -ENOMEM;
481         old = current_cred();
482 
483         retval = -EPERM;
484         if (ruid != (uid_t) -1) {
485                 new->uid = kruid;
486                 if (!uid_eq(old->uid, kruid) &&
487                     !uid_eq(old->euid, kruid) &&
488                     !ns_capable(old->user_ns, CAP_SETUID))
489                         goto error;
490         }
491 
492         if (euid != (uid_t) -1) {
493                 new->euid = keuid;
494                 if (!uid_eq(old->uid, keuid) &&
495                     !uid_eq(old->euid, keuid) &&
496                     !uid_eq(old->suid, keuid) &&
497                     !ns_capable(old->user_ns, CAP_SETUID))
498                         goto error;
499         }
500 
501         if (!uid_eq(new->uid, old->uid)) {
502                 retval = set_user(new);
503                 if (retval < 0)
504                         goto error;
505         }
506         if (ruid != (uid_t) -1 ||
507             (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
508                 new->suid = new->euid;
509         new->fsuid = new->euid;
510 
511         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
512         if (retval < 0)
513                 goto error;
514 
515         return commit_creds(new);
516 
517 error:
518         abort_creds(new);
519         return retval;
520 }
521 
522 /*
523  * setuid() is implemented like SysV with SAVED_IDS
524  *
525  * Note that SAVED_ID's is deficient in that a setuid root program
526  * like sendmail, for example, cannot set its uid to be a normal
527  * user and then switch back, because if you're root, setuid() sets
528  * the saved uid too.  If you don't like this, blame the bright people
529  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
530  * will allow a root program to temporarily drop privileges and be able to
531  * regain them by swapping the real and effective uid.
532  */
533 SYSCALL_DEFINE1(setuid, uid_t, uid)
534 {
535         struct user_namespace *ns = current_user_ns();
536         const struct cred *old;
537         struct cred *new;
538         int retval;
539         kuid_t kuid;
540 
541         kuid = make_kuid(ns, uid);
542         if (!uid_valid(kuid))
543                 return -EINVAL;
544 
545         new = prepare_creds();
546         if (!new)
547                 return -ENOMEM;
548         old = current_cred();
549 
550         retval = -EPERM;
551         if (ns_capable(old->user_ns, CAP_SETUID)) {
552                 new->suid = new->uid = kuid;
553                 if (!uid_eq(kuid, old->uid)) {
554                         retval = set_user(new);
555                         if (retval < 0)
556                                 goto error;
557                 }
558         } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
559                 goto error;
560         }
561 
562         new->fsuid = new->euid = kuid;
563 
564         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
565         if (retval < 0)
566                 goto error;
567 
568         return commit_creds(new);
569 
570 error:
571         abort_creds(new);
572         return retval;
573 }
574 
575 
576 /*
577  * This function implements a generic ability to update ruid, euid,
578  * and suid.  This allows you to implement the 4.4 compatible seteuid().
579  */
580 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
581 {
582         struct user_namespace *ns = current_user_ns();
583         const struct cred *old;
584         struct cred *new;
585         int retval;
586         kuid_t kruid, keuid, ksuid;
587 
588         kruid = make_kuid(ns, ruid);
589         keuid = make_kuid(ns, euid);
590         ksuid = make_kuid(ns, suid);
591 
592         if ((ruid != (uid_t) -1) && !uid_valid(kruid))
593                 return -EINVAL;
594 
595         if ((euid != (uid_t) -1) && !uid_valid(keuid))
596                 return -EINVAL;
597 
598         if ((suid != (uid_t) -1) && !uid_valid(ksuid))
599                 return -EINVAL;
600 
601         new = prepare_creds();
602         if (!new)
603                 return -ENOMEM;
604 
605         old = current_cred();
606 
607         retval = -EPERM;
608         if (!ns_capable(old->user_ns, CAP_SETUID)) {
609                 if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
610                     !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
611                         goto error;
612                 if (euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
613                     !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
614                         goto error;
615                 if (suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
616                     !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
617                         goto error;
618         }
619 
620         if (ruid != (uid_t) -1) {
621                 new->uid = kruid;
622                 if (!uid_eq(kruid, old->uid)) {
623                         retval = set_user(new);
624                         if (retval < 0)
625                                 goto error;
626                 }
627         }
628         if (euid != (uid_t) -1)
629                 new->euid = keuid;
630         if (suid != (uid_t) -1)
631                 new->suid = ksuid;
632         new->fsuid = new->euid;
633 
634         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
635         if (retval < 0)
636                 goto error;
637 
638         return commit_creds(new);
639 
640 error:
641         abort_creds(new);
642         return retval;
643 }
644 
645 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
646 {
647         const struct cred *cred = current_cred();
648         int retval;
649         uid_t ruid, euid, suid;
650 
651         ruid = from_kuid_munged(cred->user_ns, cred->uid);
652         euid = from_kuid_munged(cred->user_ns, cred->euid);
653         suid = from_kuid_munged(cred->user_ns, cred->suid);
654 
655         retval = put_user(ruid, ruidp);
656         if (!retval) {
657                 retval = put_user(euid, euidp);
658                 if (!retval)
659                         return put_user(suid, suidp);
660         }
661         return retval;
662 }
663 
664 /*
665  * Same as above, but for rgid, egid, sgid.
666  */
667 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
668 {
669         struct user_namespace *ns = current_user_ns();
670         const struct cred *old;
671         struct cred *new;
672         int retval;
673         kgid_t krgid, kegid, ksgid;
674 
675         krgid = make_kgid(ns, rgid);
676         kegid = make_kgid(ns, egid);
677         ksgid = make_kgid(ns, sgid);
678 
679         if ((rgid != (gid_t) -1) && !gid_valid(krgid))
680                 return -EINVAL;
681         if ((egid != (gid_t) -1) && !gid_valid(kegid))
682                 return -EINVAL;
683         if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
684                 return -EINVAL;
685 
686         new = prepare_creds();
687         if (!new)
688                 return -ENOMEM;
689         old = current_cred();
690 
691         retval = -EPERM;
692         if (!ns_capable(old->user_ns, CAP_SETGID)) {
693                 if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
694                     !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
695                         goto error;
696                 if (egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
697                     !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
698                         goto error;
699                 if (sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
700                     !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
701                         goto error;
702         }
703 
704         if (rgid != (gid_t) -1)
705                 new->gid = krgid;
706         if (egid != (gid_t) -1)
707                 new->egid = kegid;
708         if (sgid != (gid_t) -1)
709                 new->sgid = ksgid;
710         new->fsgid = new->egid;
711 
712         return commit_creds(new);
713 
714 error:
715         abort_creds(new);
716         return retval;
717 }
718 
719 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
720 {
721         const struct cred *cred = current_cred();
722         int retval;
723         gid_t rgid, egid, sgid;
724 
725         rgid = from_kgid_munged(cred->user_ns, cred->gid);
726         egid = from_kgid_munged(cred->user_ns, cred->egid);
727         sgid = from_kgid_munged(cred->user_ns, cred->sgid);
728 
729         retval = put_user(rgid, rgidp);
730         if (!retval) {
731                 retval = put_user(egid, egidp);
732                 if (!retval)
733                         retval = put_user(sgid, sgidp);
734         }
735 
736         return retval;
737 }
738 
739 
740 /*
741  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
742  * is used for "access()" and for the NFS daemon (letting nfsd stay at
743  * whatever uid it wants to). It normally shadows "euid", except when
744  * explicitly set by setfsuid() or for access..
745  */
746 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
747 {
748         const struct cred *old;
749         struct cred *new;
750         uid_t old_fsuid;
751         kuid_t kuid;
752 
753         old = current_cred();
754         old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
755 
756         kuid = make_kuid(old->user_ns, uid);
757         if (!uid_valid(kuid))
758                 return old_fsuid;
759 
760         new = prepare_creds();
761         if (!new)
762                 return old_fsuid;
763 
764         if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
765             uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
766             ns_capable(old->user_ns, CAP_SETUID)) {
767                 if (!uid_eq(kuid, old->fsuid)) {
768                         new->fsuid = kuid;
769                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
770                                 goto change_okay;
771                 }
772         }
773 
774         abort_creds(new);
775         return old_fsuid;
776 
777 change_okay:
778         commit_creds(new);
779         return old_fsuid;
780 }
781 
782 /*
783  * Samma på svenska..
784  */
785 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
786 {
787         const struct cred *old;
788         struct cred *new;
789         gid_t old_fsgid;
790         kgid_t kgid;
791 
792         old = current_cred();
793         old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
794 
795         kgid = make_kgid(old->user_ns, gid);
796         if (!gid_valid(kgid))
797                 return old_fsgid;
798 
799         new = prepare_creds();
800         if (!new)
801                 return old_fsgid;
802 
803         if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
804             gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
805             ns_capable(old->user_ns, CAP_SETGID)) {
806                 if (!gid_eq(kgid, old->fsgid)) {
807                         new->fsgid = kgid;
808                         goto change_okay;
809                 }
810         }
811 
812         abort_creds(new);
813         return old_fsgid;
814 
815 change_okay:
816         commit_creds(new);
817         return old_fsgid;
818 }
819 #endif /* CONFIG_MULTIUSER */
820 
821 /**
822  * sys_getpid - return the thread group id of the current process
823  *
824  * Note, despite the name, this returns the tgid not the pid.  The tgid and
825  * the pid are identical unless CLONE_THREAD was specified on clone() in
826  * which case the tgid is the same in all threads of the same group.
827  *
828  * This is SMP safe as current->tgid does not change.
829  */
830 SYSCALL_DEFINE0(getpid)
831 {
832         return task_tgid_vnr(current);
833 }
834 
835 /* Thread ID - the internal kernel "pid" */
836 SYSCALL_DEFINE0(gettid)
837 {
838         return task_pid_vnr(current);
839 }
840 
841 /*
842  * Accessing ->real_parent is not SMP-safe, it could
843  * change from under us. However, we can use a stale
844  * value of ->real_parent under rcu_read_lock(), see
845  * release_task()->call_rcu(delayed_put_task_struct).
846  */
847 SYSCALL_DEFINE0(getppid)
848 {
849         int pid;
850 
851         rcu_read_lock();
852         pid = task_tgid_vnr(rcu_dereference(current->real_parent));
853         rcu_read_unlock();
854 
855         return pid;
856 }
857 
858 SYSCALL_DEFINE0(getuid)
859 {
860         /* Only we change this so SMP safe */
861         return from_kuid_munged(current_user_ns(), current_uid());
862 }
863 
864 SYSCALL_DEFINE0(geteuid)
865 {
866         /* Only we change this so SMP safe */
867         return from_kuid_munged(current_user_ns(), current_euid());
868 }
869 
870 SYSCALL_DEFINE0(getgid)
871 {
872         /* Only we change this so SMP safe */
873         return from_kgid_munged(current_user_ns(), current_gid());
874 }
875 
876 SYSCALL_DEFINE0(getegid)
877 {
878         /* Only we change this so SMP safe */
879         return from_kgid_munged(current_user_ns(), current_egid());
880 }
881 
882 void do_sys_times(struct tms *tms)
883 {
884         cputime_t tgutime, tgstime, cutime, cstime;
885 
886         thread_group_cputime_adjusted(current, &tgutime, &tgstime);
887         cutime = current->signal->cutime;
888         cstime = current->signal->cstime;
889         tms->tms_utime = cputime_to_clock_t(tgutime);
890         tms->tms_stime = cputime_to_clock_t(tgstime);
891         tms->tms_cutime = cputime_to_clock_t(cutime);
892         tms->tms_cstime = cputime_to_clock_t(cstime);
893 }
894 
895 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
896 {
897         if (tbuf) {
898                 struct tms tmp;
899 
900                 do_sys_times(&tmp);
901                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
902                         return -EFAULT;
903         }
904         force_successful_syscall_return();
905         return (long) jiffies_64_to_clock_t(get_jiffies_64());
906 }
907 
908 /*
909  * This needs some heavy checking ...
910  * I just haven't the stomach for it. I also don't fully
911  * understand sessions/pgrp etc. Let somebody who does explain it.
912  *
913  * OK, I think I have the protection semantics right.... this is really
914  * only important on a multi-user system anyway, to make sure one user
915  * can't send a signal to a process owned by another.  -TYT, 12/12/91
916  *
917  * !PF_FORKNOEXEC check to conform completely to POSIX.
918  */
919 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
920 {
921         struct task_struct *p;
922         struct task_struct *group_leader = current->group_leader;
923         struct pid *pgrp;
924         int err;
925 
926         if (!pid)
927                 pid = task_pid_vnr(group_leader);
928         if (!pgid)
929                 pgid = pid;
930         if (pgid < 0)
931                 return -EINVAL;
932         rcu_read_lock();
933 
934         /* From this point forward we keep holding onto the tasklist lock
935          * so that our parent does not change from under us. -DaveM
936          */
937         write_lock_irq(&tasklist_lock);
938 
939         err = -ESRCH;
940         p = find_task_by_vpid(pid);
941         if (!p)
942                 goto out;
943 
944         err = -EINVAL;
945         if (!thread_group_leader(p))
946                 goto out;
947 
948         if (same_thread_group(p->real_parent, group_leader)) {
949                 err = -EPERM;
950                 if (task_session(p) != task_session(group_leader))
951                         goto out;
952                 err = -EACCES;
953                 if (!(p->flags & PF_FORKNOEXEC))
954                         goto out;
955         } else {
956                 err = -ESRCH;
957                 if (p != group_leader)
958                         goto out;
959         }
960 
961         err = -EPERM;
962         if (p->signal->leader)
963                 goto out;
964 
965         pgrp = task_pid(p);
966         if (pgid != pid) {
967                 struct task_struct *g;
968 
969                 pgrp = find_vpid(pgid);
970                 g = pid_task(pgrp, PIDTYPE_PGID);
971                 if (!g || task_session(g) != task_session(group_leader))
972                         goto out;
973         }
974 
975         err = security_task_setpgid(p, pgid);
976         if (err)
977                 goto out;
978 
979         if (task_pgrp(p) != pgrp)
980                 change_pid(p, PIDTYPE_PGID, pgrp);
981 
982         err = 0;
983 out:
984         /* All paths lead to here, thus we are safe. -DaveM */
985         write_unlock_irq(&tasklist_lock);
986         rcu_read_unlock();
987         return err;
988 }
989 
990 SYSCALL_DEFINE1(getpgid, pid_t, pid)
991 {
992         struct task_struct *p;
993         struct pid *grp;
994         int retval;
995 
996         rcu_read_lock();
997         if (!pid)
998                 grp = task_pgrp(current);
999         else {
1000                 retval = -ESRCH;
1001                 p = find_task_by_vpid(pid);
1002                 if (!p)
1003                         goto out;
1004                 grp = task_pgrp(p);
1005                 if (!grp)
1006                         goto out;
1007 
1008                 retval = security_task_getpgid(p);
1009                 if (retval)
1010                         goto out;
1011         }
1012         retval = pid_vnr(grp);
1013 out:
1014         rcu_read_unlock();
1015         return retval;
1016 }
1017 
1018 #ifdef __ARCH_WANT_SYS_GETPGRP
1019 
1020 SYSCALL_DEFINE0(getpgrp)
1021 {
1022         return sys_getpgid(0);
1023 }
1024 
1025 #endif
1026 
1027 SYSCALL_DEFINE1(getsid, pid_t, pid)
1028 {
1029         struct task_struct *p;
1030         struct pid *sid;
1031         int retval;
1032 
1033         rcu_read_lock();
1034         if (!pid)
1035                 sid = task_session(current);
1036         else {
1037                 retval = -ESRCH;
1038                 p = find_task_by_vpid(pid);
1039                 if (!p)
1040                         goto out;
1041                 sid = task_session(p);
1042                 if (!sid)
1043                         goto out;
1044 
1045                 retval = security_task_getsid(p);
1046                 if (retval)
1047                         goto out;
1048         }
1049         retval = pid_vnr(sid);
1050 out:
1051         rcu_read_unlock();
1052         return retval;
1053 }
1054 
1055 static void set_special_pids(struct pid *pid)
1056 {
1057         struct task_struct *curr = current->group_leader;
1058 
1059         if (task_session(curr) != pid)
1060                 change_pid(curr, PIDTYPE_SID, pid);
1061 
1062         if (task_pgrp(curr) != pid)
1063                 change_pid(curr, PIDTYPE_PGID, pid);
1064 }
1065 
1066 SYSCALL_DEFINE0(setsid)
1067 {
1068         struct task_struct *group_leader = current->group_leader;
1069         struct pid *sid = task_pid(group_leader);
1070         pid_t session = pid_vnr(sid);
1071         int err = -EPERM;
1072 
1073         write_lock_irq(&tasklist_lock);
1074         /* Fail if I am already a session leader */
1075         if (group_leader->signal->leader)
1076                 goto out;
1077 
1078         /* Fail if a process group id already exists that equals the
1079          * proposed session id.
1080          */
1081         if (pid_task(sid, PIDTYPE_PGID))
1082                 goto out;
1083 
1084         group_leader->signal->leader = 1;
1085         set_special_pids(sid);
1086 
1087         proc_clear_tty(group_leader);
1088 
1089         err = session;
1090 out:
1091         write_unlock_irq(&tasklist_lock);
1092         if (err > 0) {
1093                 proc_sid_connector(group_leader);
1094                 sched_autogroup_create_attach(group_leader);
1095         }
1096         return err;
1097 }
1098 
1099 DECLARE_RWSEM(uts_sem);
1100 
1101 #ifdef COMPAT_UTS_MACHINE
1102 #define override_architecture(name) \
1103         (personality(current->personality) == PER_LINUX32 && \
1104          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1105                       sizeof(COMPAT_UTS_MACHINE)))
1106 #else
1107 #define override_architecture(name)     0
1108 #endif
1109 
1110 /*
1111  * Work around broken programs that cannot handle "Linux 3.0".
1112  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1113  * And we map 4.x to 2.6.60+x, so 4.0 would be 2.6.60.
1114  */
1115 static int override_release(char __user *release, size_t len)
1116 {
1117         int ret = 0;
1118 
1119         if (current->personality & UNAME26) {
1120                 const char *rest = UTS_RELEASE;
1121                 char buf[65] = { 0 };
1122                 int ndots = 0;
1123                 unsigned v;
1124                 size_t copy;
1125 
1126                 while (*rest) {
1127                         if (*rest == '.' && ++ndots >= 3)
1128                                 break;
1129                         if (!isdigit(*rest) && *rest != '.')
1130                                 break;
1131                         rest++;
1132                 }
1133                 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 60;
1134                 copy = clamp_t(size_t, len, 1, sizeof(buf));
1135                 copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
1136                 ret = copy_to_user(release, buf, copy + 1);
1137         }
1138         return ret;
1139 }
1140 
1141 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1142 {
1143         int errno = 0;
1144 
1145         down_read(&uts_sem);
1146         if (copy_to_user(name, utsname(), sizeof *name))
1147                 errno = -EFAULT;
1148         up_read(&uts_sem);
1149 
1150         if (!errno && override_release(name->release, sizeof(name->release)))
1151                 errno = -EFAULT;
1152         if (!errno && override_architecture(name))
1153                 errno = -EFAULT;
1154         return errno;
1155 }
1156 
1157 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1158 /*
1159  * Old cruft
1160  */
1161 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1162 {
1163         int error = 0;
1164 
1165         if (!name)
1166                 return -EFAULT;
1167 
1168         down_read(&uts_sem);
1169         if (copy_to_user(name, utsname(), sizeof(*name)))
1170                 error = -EFAULT;
1171         up_read(&uts_sem);
1172 
1173         if (!error && override_release(name->release, sizeof(name->release)))
1174                 error = -EFAULT;
1175         if (!error && override_architecture(name))
1176                 error = -EFAULT;
1177         return error;
1178 }
1179 
1180 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1181 {
1182         int error;
1183 
1184         if (!name)
1185                 return -EFAULT;
1186         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1187                 return -EFAULT;
1188 
1189         down_read(&uts_sem);
1190         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1191                                __OLD_UTS_LEN);
1192         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1193         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1194                                 __OLD_UTS_LEN);
1195         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1196         error |= __copy_to_user(&name->release, &utsname()->release,
1197                                 __OLD_UTS_LEN);
1198         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1199         error |= __copy_to_user(&name->version, &utsname()->version,
1200                                 __OLD_UTS_LEN);
1201         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1202         error |= __copy_to_user(&name->machine, &utsname()->machine,
1203                                 __OLD_UTS_LEN);
1204         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1205         up_read(&uts_sem);
1206 
1207         if (!error && override_architecture(name))
1208                 error = -EFAULT;
1209         if (!error && override_release(name->release, sizeof(name->release)))
1210                 error = -EFAULT;
1211         return error ? -EFAULT : 0;
1212 }
1213 #endif
1214 
1215 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1216 {
1217         int errno;
1218         char tmp[__NEW_UTS_LEN];
1219 
1220         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1221                 return -EPERM;
1222 
1223         if (len < 0 || len > __NEW_UTS_LEN)
1224                 return -EINVAL;
1225         down_write(&uts_sem);
1226         errno = -EFAULT;
1227         if (!copy_from_user(tmp, name, len)) {
1228                 struct new_utsname *u = utsname();
1229 
1230                 memcpy(u->nodename, tmp, len);
1231                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1232                 errno = 0;
1233                 uts_proc_notify(UTS_PROC_HOSTNAME);
1234         }
1235         up_write(&uts_sem);
1236         return errno;
1237 }
1238 
1239 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1240 
1241 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1242 {
1243         int i, errno;
1244         struct new_utsname *u;
1245 
1246         if (len < 0)
1247                 return -EINVAL;
1248         down_read(&uts_sem);
1249         u = utsname();
1250         i = 1 + strlen(u->nodename);
1251         if (i > len)
1252                 i = len;
1253         errno = 0;
1254         if (copy_to_user(name, u->nodename, i))
1255                 errno = -EFAULT;
1256         up_read(&uts_sem);
1257         return errno;
1258 }
1259 
1260 #endif
1261 
1262 /*
1263  * Only setdomainname; getdomainname can be implemented by calling
1264  * uname()
1265  */
1266 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1267 {
1268         int errno;
1269         char tmp[__NEW_UTS_LEN];
1270 
1271         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1272                 return -EPERM;
1273         if (len < 0 || len > __NEW_UTS_LEN)
1274                 return -EINVAL;
1275 
1276         down_write(&uts_sem);
1277         errno = -EFAULT;
1278         if (!copy_from_user(tmp, name, len)) {
1279                 struct new_utsname *u = utsname();
1280 
1281                 memcpy(u->domainname, tmp, len);
1282                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1283                 errno = 0;
1284                 uts_proc_notify(UTS_PROC_DOMAINNAME);
1285         }
1286         up_write(&uts_sem);
1287         return errno;
1288 }
1289 
1290 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1291 {
1292         struct rlimit value;
1293         int ret;
1294 
1295         ret = do_prlimit(current, resource, NULL, &value);
1296         if (!ret)
1297                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1298 
1299         return ret;
1300 }
1301 
1302 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1303 
1304 /*
1305  *      Back compatibility for getrlimit. Needed for some apps.
1306  */
1307 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1308                 struct rlimit __user *, rlim)
1309 {
1310         struct rlimit x;
1311         if (resource >= RLIM_NLIMITS)
1312                 return -EINVAL;
1313 
1314         task_lock(current->group_leader);
1315         x = current->signal->rlim[resource];
1316         task_unlock(current->group_leader);
1317         if (x.rlim_cur > 0x7FFFFFFF)
1318                 x.rlim_cur = 0x7FFFFFFF;
1319         if (x.rlim_max > 0x7FFFFFFF)
1320                 x.rlim_max = 0x7FFFFFFF;
1321         return copy_to_user(rlim, &x, sizeof(x)) ? -EFAULT : 0;
1322 }
1323 
1324 #endif
1325 
1326 static inline bool rlim64_is_infinity(__u64 rlim64)
1327 {
1328 #if BITS_PER_LONG < 64
1329         return rlim64 >= ULONG_MAX;
1330 #else
1331         return rlim64 == RLIM64_INFINITY;
1332 #endif
1333 }
1334 
1335 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1336 {
1337         if (rlim->rlim_cur == RLIM_INFINITY)
1338                 rlim64->rlim_cur = RLIM64_INFINITY;
1339         else
1340                 rlim64->rlim_cur = rlim->rlim_cur;
1341         if (rlim->rlim_max == RLIM_INFINITY)
1342                 rlim64->rlim_max = RLIM64_INFINITY;
1343         else
1344                 rlim64->rlim_max = rlim->rlim_max;
1345 }
1346 
1347 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1348 {
1349         if (rlim64_is_infinity(rlim64->rlim_cur))
1350                 rlim->rlim_cur = RLIM_INFINITY;
1351         else
1352                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1353         if (rlim64_is_infinity(rlim64->rlim_max))
1354                 rlim->rlim_max = RLIM_INFINITY;
1355         else
1356                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1357 }
1358 
1359 /* make sure you are allowed to change @tsk limits before calling this */
1360 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1361                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1362 {
1363         struct rlimit *rlim;
1364         int retval = 0;
1365 
1366         if (resource >= RLIM_NLIMITS)
1367                 return -EINVAL;
1368         if (new_rlim) {
1369                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1370                         return -EINVAL;
1371                 if (resource == RLIMIT_NOFILE &&
1372                                 new_rlim->rlim_max > sysctl_nr_open)
1373                         return -EPERM;
1374         }
1375 
1376         /* protect tsk->signal and tsk->sighand from disappearing */
1377         read_lock(&tasklist_lock);
1378         if (!tsk->sighand) {
1379                 retval = -ESRCH;
1380                 goto out;
1381         }
1382 
1383         rlim = tsk->signal->rlim + resource;
1384         task_lock(tsk->group_leader);
1385         if (new_rlim) {
1386                 /* Keep the capable check against init_user_ns until
1387                    cgroups can contain all limits */
1388                 if (new_rlim->rlim_max > rlim->rlim_max &&
1389                                 !capable(CAP_SYS_RESOURCE))
1390                         retval = -EPERM;
1391                 if (!retval)
1392                         retval = security_task_setrlimit(tsk->group_leader,
1393                                         resource, new_rlim);
1394                 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1395                         /*
1396                          * The caller is asking for an immediate RLIMIT_CPU
1397                          * expiry.  But we use the zero value to mean "it was
1398                          * never set".  So let's cheat and make it one second
1399                          * instead
1400                          */
1401                         new_rlim->rlim_cur = 1;
1402                 }
1403         }
1404         if (!retval) {
1405                 if (old_rlim)
1406                         *old_rlim = *rlim;
1407                 if (new_rlim)
1408                         *rlim = *new_rlim;
1409         }
1410         task_unlock(tsk->group_leader);
1411 
1412         /*
1413          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1414          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1415          * very long-standing error, and fixing it now risks breakage of
1416          * applications, so we live with it
1417          */
1418          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1419              new_rlim->rlim_cur != RLIM_INFINITY &&
1420              IS_ENABLED(CONFIG_POSIX_TIMERS))
1421                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1422 out:
1423         read_unlock(&tasklist_lock);
1424         return retval;
1425 }
1426 
1427 /* rcu lock must be held */
1428 static int check_prlimit_permission(struct task_struct *task)
1429 {
1430         const struct cred *cred = current_cred(), *tcred;
1431 
1432         if (current == task)
1433                 return 0;
1434 
1435         tcred = __task_cred(task);
1436         if (uid_eq(cred->uid, tcred->euid) &&
1437             uid_eq(cred->uid, tcred->suid) &&
1438             uid_eq(cred->uid, tcred->uid)  &&
1439             gid_eq(cred->gid, tcred->egid) &&
1440             gid_eq(cred->gid, tcred->sgid) &&
1441             gid_eq(cred->gid, tcred->gid))
1442                 return 0;
1443         if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1444                 return 0;
1445 
1446         return -EPERM;
1447 }
1448 
1449 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1450                 const struct rlimit64 __user *, new_rlim,
1451                 struct rlimit64 __user *, old_rlim)
1452 {
1453         struct rlimit64 old64, new64;
1454         struct rlimit old, new;
1455         struct task_struct *tsk;
1456         int ret;
1457 
1458         if (new_rlim) {
1459                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1460                         return -EFAULT;
1461                 rlim64_to_rlim(&new64, &new);
1462         }
1463 
1464         rcu_read_lock();
1465         tsk = pid ? find_task_by_vpid(pid) : current;
1466         if (!tsk) {
1467                 rcu_read_unlock();
1468                 return -ESRCH;
1469         }
1470         ret = check_prlimit_permission(tsk);
1471         if (ret) {
1472                 rcu_read_unlock();
1473                 return ret;
1474         }
1475         get_task_struct(tsk);
1476         rcu_read_unlock();
1477 
1478         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1479                         old_rlim ? &old : NULL);
1480 
1481         if (!ret && old_rlim) {
1482                 rlim_to_rlim64(&old, &old64);
1483                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1484                         ret = -EFAULT;
1485         }
1486 
1487         put_task_struct(tsk);
1488         return ret;
1489 }
1490 
1491 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1492 {
1493         struct rlimit new_rlim;
1494 
1495         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1496                 return -EFAULT;
1497         return do_prlimit(current, resource, &new_rlim, NULL);
1498 }
1499 
1500 /*
1501  * It would make sense to put struct rusage in the task_struct,
1502  * except that would make the task_struct be *really big*.  After
1503  * task_struct gets moved into malloc'ed memory, it would
1504  * make sense to do this.  It will make moving the rest of the information
1505  * a lot simpler!  (Which we're not doing right now because we're not
1506  * measuring them yet).
1507  *
1508  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1509  * races with threads incrementing their own counters.  But since word
1510  * reads are atomic, we either get new values or old values and we don't
1511  * care which for the sums.  We always take the siglock to protect reading
1512  * the c* fields from p->signal from races with exit.c updating those
1513  * fields when reaping, so a sample either gets all the additions of a
1514  * given child after it's reaped, or none so this sample is before reaping.
1515  *
1516  * Locking:
1517  * We need to take the siglock for CHILDEREN, SELF and BOTH
1518  * for  the cases current multithreaded, non-current single threaded
1519  * non-current multithreaded.  Thread traversal is now safe with
1520  * the siglock held.
1521  * Strictly speaking, we donot need to take the siglock if we are current and
1522  * single threaded,  as no one else can take our signal_struct away, no one
1523  * else can  reap the  children to update signal->c* counters, and no one else
1524  * can race with the signal-> fields. If we do not take any lock, the
1525  * signal-> fields could be read out of order while another thread was just
1526  * exiting. So we should  place a read memory barrier when we avoid the lock.
1527  * On the writer side,  write memory barrier is implied in  __exit_signal
1528  * as __exit_signal releases  the siglock spinlock after updating the signal->
1529  * fields. But we don't do this yet to keep things simple.
1530  *
1531  */
1532 
1533 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1534 {
1535         r->ru_nvcsw += t->nvcsw;
1536         r->ru_nivcsw += t->nivcsw;
1537         r->ru_minflt += t->min_flt;
1538         r->ru_majflt += t->maj_flt;
1539         r->ru_inblock += task_io_get_inblock(t);
1540         r->ru_oublock += task_io_get_oublock(t);
1541 }
1542 
1543 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1544 {
1545         struct task_struct *t;
1546         unsigned long flags;
1547         cputime_t tgutime, tgstime, utime, stime;
1548         unsigned long maxrss = 0;
1549 
1550         memset((char *)r, 0, sizeof (*r));
1551         utime = stime = 0;
1552 
1553         if (who == RUSAGE_THREAD) {
1554                 task_cputime_adjusted(current, &utime, &stime);
1555                 accumulate_thread_rusage(p, r);
1556                 maxrss = p->signal->maxrss;
1557                 goto out;
1558         }
1559 
1560         if (!lock_task_sighand(p, &flags))
1561                 return;
1562 
1563         switch (who) {
1564         case RUSAGE_BOTH:
1565         case RUSAGE_CHILDREN:
1566                 utime = p->signal->cutime;
1567                 stime = p->signal->cstime;
1568                 r->ru_nvcsw = p->signal->cnvcsw;
1569                 r->ru_nivcsw = p->signal->cnivcsw;
1570                 r->ru_minflt = p->signal->cmin_flt;
1571                 r->ru_majflt = p->signal->cmaj_flt;
1572                 r->ru_inblock = p->signal->cinblock;
1573                 r->ru_oublock = p->signal->coublock;
1574                 maxrss = p->signal->cmaxrss;
1575 
1576                 if (who == RUSAGE_CHILDREN)
1577                         break;
1578 
1579         case RUSAGE_SELF:
1580                 thread_group_cputime_adjusted(p, &tgutime, &tgstime);
1581                 utime += tgutime;
1582                 stime += tgstime;
1583                 r->ru_nvcsw += p->signal->nvcsw;
1584                 r->ru_nivcsw += p->signal->nivcsw;
1585                 r->ru_minflt += p->signal->min_flt;
1586                 r->ru_majflt += p->signal->maj_flt;
1587                 r->ru_inblock += p->signal->inblock;
1588                 r->ru_oublock += p->signal->oublock;
1589                 if (maxrss < p->signal->maxrss)
1590                         maxrss = p->signal->maxrss;
1591                 t = p;
1592                 do {
1593                         accumulate_thread_rusage(t, r);
1594                 } while_each_thread(p, t);
1595                 break;
1596 
1597         default:
1598                 BUG();
1599         }
1600         unlock_task_sighand(p, &flags);
1601 
1602 out:
1603         cputime_to_timeval(utime, &r->ru_utime);
1604         cputime_to_timeval(stime, &r->ru_stime);
1605 
1606         if (who != RUSAGE_CHILDREN) {
1607                 struct mm_struct *mm = get_task_mm(p);
1608 
1609                 if (mm) {
1610                         setmax_mm_hiwater_rss(&maxrss, mm);
1611                         mmput(mm);
1612                 }
1613         }
1614         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1615 }
1616 
1617 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1618 {
1619         struct rusage r;
1620 
1621         k_getrusage(p, who, &r);
1622         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1623 }
1624 
1625 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1626 {
1627         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1628             who != RUSAGE_THREAD)
1629                 return -EINVAL;
1630         return getrusage(current, who, ru);
1631 }
1632 
1633 #ifdef CONFIG_COMPAT
1634 COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru)
1635 {
1636         struct rusage r;
1637 
1638         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1639             who != RUSAGE_THREAD)
1640                 return -EINVAL;
1641 
1642         k_getrusage(current, who, &r);
1643         return put_compat_rusage(&r, ru);
1644 }
1645 #endif
1646 
1647 SYSCALL_DEFINE1(umask, int, mask)
1648 {
1649         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1650         return mask;
1651 }
1652 
1653 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1654 {
1655         struct fd exe;
1656         struct file *old_exe, *exe_file;
1657         struct inode *inode;
1658         int err;
1659 
1660         exe = fdget(fd);
1661         if (!exe.file)
1662                 return -EBADF;
1663 
1664         inode = file_inode(exe.file);
1665 
1666         /*
1667          * Because the original mm->exe_file points to executable file, make
1668          * sure that this one is executable as well, to avoid breaking an
1669          * overall picture.
1670          */
1671         err = -EACCES;
1672         if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path))
1673                 goto exit;
1674 
1675         err = inode_permission(inode, MAY_EXEC);
1676         if (err)
1677                 goto exit;
1678 
1679         /*
1680          * Forbid mm->exe_file change if old file still mapped.
1681          */
1682         exe_file = get_mm_exe_file(mm);
1683         err = -EBUSY;
1684         if (exe_file) {
1685                 struct vm_area_struct *vma;
1686 
1687                 down_read(&mm->mmap_sem);
1688                 for (vma = mm->mmap; vma; vma = vma->vm_next) {
1689                         if (!vma->vm_file)
1690                                 continue;
1691                         if (path_equal(&vma->vm_file->f_path,
1692                                        &exe_file->f_path))
1693                                 goto exit_err;
1694                 }
1695 
1696                 up_read(&mm->mmap_sem);
1697                 fput(exe_file);
1698         }
1699 
1700         err = 0;
1701         /* set the new file, lockless */
1702         get_file(exe.file);
1703         old_exe = xchg(&mm->exe_file, exe.file);
1704         if (old_exe)
1705                 fput(old_exe);
1706 exit:
1707         fdput(exe);
1708         return err;
1709 exit_err:
1710         up_read(&mm->mmap_sem);
1711         fput(exe_file);
1712         goto exit;
1713 }
1714 
1715 /*
1716  * WARNING: we don't require any capability here so be very careful
1717  * in what is allowed for modification from userspace.
1718  */
1719 static int validate_prctl_map(struct prctl_mm_map *prctl_map)
1720 {
1721         unsigned long mmap_max_addr = TASK_SIZE;
1722         struct mm_struct *mm = current->mm;
1723         int error = -EINVAL, i;
1724 
1725         static const unsigned char offsets[] = {
1726                 offsetof(struct prctl_mm_map, start_code),
1727                 offsetof(struct prctl_mm_map, end_code),
1728                 offsetof(struct prctl_mm_map, start_data),
1729                 offsetof(struct prctl_mm_map, end_data),
1730                 offsetof(struct prctl_mm_map, start_brk),
1731                 offsetof(struct prctl_mm_map, brk),
1732                 offsetof(struct prctl_mm_map, start_stack),
1733                 offsetof(struct prctl_mm_map, arg_start),
1734                 offsetof(struct prctl_mm_map, arg_end),
1735                 offsetof(struct prctl_mm_map, env_start),
1736                 offsetof(struct prctl_mm_map, env_end),
1737         };
1738 
1739         /*
1740          * Make sure the members are not somewhere outside
1741          * of allowed address space.
1742          */
1743         for (i = 0; i < ARRAY_SIZE(offsets); i++) {
1744                 u64 val = *(u64 *)((char *)prctl_map + offsets[i]);
1745 
1746                 if ((unsigned long)val >= mmap_max_addr ||
1747                     (unsigned long)val < mmap_min_addr)
1748                         goto out;
1749         }
1750 
1751         /*
1752          * Make sure the pairs are ordered.
1753          */
1754 #define __prctl_check_order(__m1, __op, __m2)                           \
1755         ((unsigned long)prctl_map->__m1 __op                            \
1756          (unsigned long)prctl_map->__m2) ? 0 : -EINVAL
1757         error  = __prctl_check_order(start_code, <, end_code);
1758         error |= __prctl_check_order(start_data, <, end_data);
1759         error |= __prctl_check_order(start_brk, <=, brk);
1760         error |= __prctl_check_order(arg_start, <=, arg_end);
1761         error |= __prctl_check_order(env_start, <=, env_end);
1762         if (error)
1763                 goto out;
1764 #undef __prctl_check_order
1765 
1766         error = -EINVAL;
1767 
1768         /*
1769          * @brk should be after @end_data in traditional maps.
1770          */
1771         if (prctl_map->start_brk <= prctl_map->end_data ||
1772             prctl_map->brk <= prctl_map->end_data)
1773                 goto out;
1774 
1775         /*
1776          * Neither we should allow to override limits if they set.
1777          */
1778         if (check_data_rlimit(rlimit(RLIMIT_DATA), prctl_map->brk,
1779                               prctl_map->start_brk, prctl_map->end_data,
1780                               prctl_map->start_data))
1781                         goto out;
1782 
1783         /*
1784          * Someone is trying to cheat the auxv vector.
1785          */
1786         if (prctl_map->auxv_size) {
1787                 if (!prctl_map->auxv || prctl_map->auxv_size > sizeof(mm->saved_auxv))
1788                         goto out;
1789         }
1790 
1791         /*
1792          * Finally, make sure the caller has the rights to
1793          * change /proc/pid/exe link: only local root should
1794          * be allowed to.
1795          */
1796         if (prctl_map->exe_fd != (u32)-1) {
1797                 struct user_namespace *ns = current_user_ns();
1798                 const struct cred *cred = current_cred();
1799 
1800                 if (!uid_eq(cred->uid, make_kuid(ns, 0)) ||
1801                     !gid_eq(cred->gid, make_kgid(ns, 0)))
1802                         goto out;
1803         }
1804 
1805         error = 0;
1806 out:
1807         return error;
1808 }
1809 
1810 #ifdef CONFIG_CHECKPOINT_RESTORE
1811 static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size)
1812 {
1813         struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, };
1814         unsigned long user_auxv[AT_VECTOR_SIZE];
1815         struct mm_struct *mm = current->mm;
1816         int error;
1817 
1818         BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1819         BUILD_BUG_ON(sizeof(struct prctl_mm_map) > 256);
1820 
1821         if (opt == PR_SET_MM_MAP_SIZE)
1822                 return put_user((unsigned int)sizeof(prctl_map),
1823                                 (unsigned int __user *)addr);
1824 
1825         if (data_size != sizeof(prctl_map))
1826                 return -EINVAL;
1827 
1828         if (copy_from_user(&prctl_map, addr, sizeof(prctl_map)))
1829                 return -EFAULT;
1830 
1831         error = validate_prctl_map(&prctl_map);
1832         if (error)
1833                 return error;
1834 
1835         if (prctl_map.auxv_size) {
1836                 memset(user_auxv, 0, sizeof(user_auxv));
1837                 if (copy_from_user(user_auxv,
1838                                    (const void __user *)prctl_map.auxv,
1839                                    prctl_map.auxv_size))
1840                         return -EFAULT;
1841 
1842                 /* Last entry must be AT_NULL as specification requires */
1843                 user_auxv[AT_VECTOR_SIZE - 2] = AT_NULL;
1844                 user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL;
1845         }
1846 
1847         if (prctl_map.exe_fd != (u32)-1) {
1848                 error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd);
1849                 if (error)
1850                         return error;
1851         }
1852 
1853         down_write(&mm->mmap_sem);
1854 
1855         /*
1856          * We don't validate if these members are pointing to
1857          * real present VMAs because application may have correspond
1858          * VMAs already unmapped and kernel uses these members for statistics
1859          * output in procfs mostly, except
1860          *
1861          *  - @start_brk/@brk which are used in do_brk but kernel lookups
1862          *    for VMAs when updating these memvers so anything wrong written
1863          *    here cause kernel to swear at userspace program but won't lead
1864          *    to any problem in kernel itself
1865          */
1866 
1867         mm->start_code  = prctl_map.start_code;
1868         mm->end_code    = prctl_map.end_code;
1869         mm->start_data  = prctl_map.start_data;
1870         mm->end_data    = prctl_map.end_data;
1871         mm->start_brk   = prctl_map.start_brk;
1872         mm->brk         = prctl_map.brk;
1873         mm->start_stack = prctl_map.start_stack;
1874         mm->arg_start   = prctl_map.arg_start;
1875         mm->arg_end     = prctl_map.arg_end;
1876         mm->env_start   = prctl_map.env_start;
1877         mm->env_end     = prctl_map.env_end;
1878 
1879         /*
1880          * Note this update of @saved_auxv is lockless thus
1881          * if someone reads this member in procfs while we're
1882          * updating -- it may get partly updated results. It's
1883          * known and acceptable trade off: we leave it as is to
1884          * not introduce additional locks here making the kernel
1885          * more complex.
1886          */
1887         if (prctl_map.auxv_size)
1888                 memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv));
1889 
1890         up_write(&mm->mmap_sem);
1891         return 0;
1892 }
1893 #endif /* CONFIG_CHECKPOINT_RESTORE */
1894 
1895 static int prctl_set_auxv(struct mm_struct *mm, unsigned long addr,
1896                           unsigned long len)
1897 {
1898         /*
1899          * This doesn't move the auxiliary vector itself since it's pinned to
1900          * mm_struct, but it permits filling the vector with new values.  It's
1901          * up to the caller to provide sane values here, otherwise userspace
1902          * tools which use this vector might be unhappy.
1903          */
1904         unsigned long user_auxv[AT_VECTOR_SIZE];
1905 
1906         if (len > sizeof(user_auxv))
1907                 return -EINVAL;
1908 
1909         if (copy_from_user(user_auxv, (const void __user *)addr, len))
1910                 return -EFAULT;
1911 
1912         /* Make sure the last entry is always AT_NULL */
1913         user_auxv[AT_VECTOR_SIZE - 2] = 0;
1914         user_auxv[AT_VECTOR_SIZE - 1] = 0;
1915 
1916         BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1917 
1918         task_lock(current);
1919         memcpy(mm->saved_auxv, user_auxv, len);
1920         task_unlock(current);
1921 
1922         return 0;
1923 }
1924 
1925 static int prctl_set_mm(int opt, unsigned long addr,
1926                         unsigned long arg4, unsigned long arg5)
1927 {
1928         struct mm_struct *mm = current->mm;
1929         struct prctl_mm_map prctl_map;
1930         struct vm_area_struct *vma;
1931         int error;
1932 
1933         if (arg5 || (arg4 && (opt != PR_SET_MM_AUXV &&
1934                               opt != PR_SET_MM_MAP &&
1935                               opt != PR_SET_MM_MAP_SIZE)))
1936                 return -EINVAL;
1937 
1938 #ifdef CONFIG_CHECKPOINT_RESTORE
1939         if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE)
1940                 return prctl_set_mm_map(opt, (const void __user *)addr, arg4);
1941 #endif
1942 
1943         if (!capable(CAP_SYS_RESOURCE))
1944                 return -EPERM;
1945 
1946         if (opt == PR_SET_MM_EXE_FILE)
1947                 return prctl_set_mm_exe_file(mm, (unsigned int)addr);
1948 
1949         if (opt == PR_SET_MM_AUXV)
1950                 return prctl_set_auxv(mm, addr, arg4);
1951 
1952         if (addr >= TASK_SIZE || addr < mmap_min_addr)
1953                 return -EINVAL;
1954 
1955         error = -EINVAL;
1956 
1957         down_write(&mm->mmap_sem);
1958         vma = find_vma(mm, addr);
1959 
1960         prctl_map.start_code    = mm->start_code;
1961         prctl_map.end_code      = mm->end_code;
1962         prctl_map.start_data    = mm->start_data;
1963         prctl_map.end_data      = mm->end_data;
1964         prctl_map.start_brk     = mm->start_brk;
1965         prctl_map.brk           = mm->brk;
1966         prctl_map.start_stack   = mm->start_stack;
1967         prctl_map.arg_start     = mm->arg_start;
1968         prctl_map.arg_end       = mm->arg_end;
1969         prctl_map.env_start     = mm->env_start;
1970         prctl_map.env_end       = mm->env_end;
1971         prctl_map.auxv          = NULL;
1972         prctl_map.auxv_size     = 0;
1973         prctl_map.exe_fd        = -1;
1974 
1975         switch (opt) {
1976         case PR_SET_MM_START_CODE:
1977                 prctl_map.start_code = addr;
1978                 break;
1979         case PR_SET_MM_END_CODE:
1980                 prctl_map.end_code = addr;
1981                 break;
1982         case PR_SET_MM_START_DATA:
1983                 prctl_map.start_data = addr;
1984                 break;
1985         case PR_SET_MM_END_DATA:
1986                 prctl_map.end_data = addr;
1987                 break;
1988         case PR_SET_MM_START_STACK:
1989                 prctl_map.start_stack = addr;
1990                 break;
1991         case PR_SET_MM_START_BRK:
1992                 prctl_map.start_brk = addr;
1993                 break;
1994         case PR_SET_MM_BRK:
1995                 prctl_map.brk = addr;
1996                 break;
1997         case PR_SET_MM_ARG_START:
1998                 prctl_map.arg_start = addr;
1999                 break;
2000         case PR_SET_MM_ARG_END:
2001                 prctl_map.arg_end = addr;
2002                 break;
2003         case PR_SET_MM_ENV_START:
2004                 prctl_map.env_start = addr;
2005                 break;
2006         case PR_SET_MM_ENV_END:
2007                 prctl_map.env_end = addr;
2008                 break;
2009         default:
2010                 goto out;
2011         }
2012 
2013         error = validate_prctl_map(&prctl_map);
2014         if (error)
2015                 goto out;
2016 
2017         switch (opt) {
2018         /*
2019          * If command line arguments and environment
2020          * are placed somewhere else on stack, we can
2021          * set them up here, ARG_START/END to setup
2022          * command line argumets and ENV_START/END
2023          * for environment.
2024          */
2025         case PR_SET_MM_START_STACK:
2026         case PR_SET_MM_ARG_START:
2027         case PR_SET_MM_ARG_END:
2028         case PR_SET_MM_ENV_START:
2029         case PR_SET_MM_ENV_END:
2030                 if (!vma) {
2031                         error = -EFAULT;
2032                         goto out;
2033                 }
2034         }
2035 
2036         mm->start_code  = prctl_map.start_code;
2037         mm->end_code    = prctl_map.end_code;
2038         mm->start_data  = prctl_map.start_data;
2039         mm->end_data    = prctl_map.end_data;
2040         mm->start_brk   = prctl_map.start_brk;
2041         mm->brk         = prctl_map.brk;
2042         mm->start_stack = prctl_map.start_stack;
2043         mm->arg_start   = prctl_map.arg_start;
2044         mm->arg_end     = prctl_map.arg_end;
2045         mm->env_start   = prctl_map.env_start;
2046         mm->env_end     = prctl_map.env_end;
2047 
2048         error = 0;
2049 out:
2050         up_write(&mm->mmap_sem);
2051         return error;
2052 }
2053 
2054 #ifdef CONFIG_CHECKPOINT_RESTORE
2055 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
2056 {
2057         return put_user(me->clear_child_tid, tid_addr);
2058 }
2059 #else
2060 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
2061 {
2062         return -EINVAL;
2063 }
2064 #endif
2065 
2066 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2067                 unsigned long, arg4, unsigned long, arg5)
2068 {
2069         struct task_struct *me = current;
2070         unsigned char comm[sizeof(me->comm)];
2071         long error;
2072 
2073         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2074         if (error != -ENOSYS)
2075                 return error;
2076 
2077         error = 0;
2078         switch (option) {
2079         case PR_SET_PDEATHSIG:
2080                 if (!valid_signal(arg2)) {
2081                         error = -EINVAL;
2082                         break;
2083                 }
2084                 me->pdeath_signal = arg2;
2085                 break;
2086         case PR_GET_PDEATHSIG:
2087                 error = put_user(me->pdeath_signal, (int __user *)arg2);
2088                 break;
2089         case PR_GET_DUMPABLE:
2090                 error = get_dumpable(me->mm);
2091                 break;
2092         case PR_SET_DUMPABLE:
2093                 if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
2094                         error = -EINVAL;
2095                         break;
2096                 }
2097                 set_dumpable(me->mm, arg2);
2098                 break;
2099 
2100         case PR_SET_UNALIGN:
2101                 error = SET_UNALIGN_CTL(me, arg2);
2102                 break;
2103         case PR_GET_UNALIGN:
2104                 error = GET_UNALIGN_CTL(me, arg2);
2105                 break;
2106         case PR_SET_FPEMU:
2107                 error = SET_FPEMU_CTL(me, arg2);
2108                 break;
2109         case PR_GET_FPEMU:
2110                 error = GET_FPEMU_CTL(me, arg2);
2111                 break;
2112         case PR_SET_FPEXC:
2113                 error = SET_FPEXC_CTL(me, arg2);
2114                 break;
2115         case PR_GET_FPEXC:
2116                 error = GET_FPEXC_CTL(me, arg2);
2117                 break;
2118         case PR_GET_TIMING:
2119                 error = PR_TIMING_STATISTICAL;
2120                 break;
2121         case PR_SET_TIMING:
2122                 if (arg2 != PR_TIMING_STATISTICAL)
2123                         error = -EINVAL;
2124                 break;
2125         case PR_SET_NAME:
2126                 comm[sizeof(me->comm) - 1] = 0;
2127                 if (strncpy_from_user(comm, (char __user *)arg2,
2128                                       sizeof(me->comm) - 1) < 0)
2129                         return -EFAULT;
2130                 set_task_comm(me, comm);
2131                 proc_comm_connector(me);
2132                 break;
2133         case PR_GET_NAME:
2134                 get_task_comm(comm, me);
2135                 if (copy_to_user((char __user *)arg2, comm, sizeof(comm)))
2136                         return -EFAULT;
2137                 break;
2138         case PR_GET_ENDIAN:
2139                 error = GET_ENDIAN(me, arg2);
2140                 break;
2141         case PR_SET_ENDIAN:
2142                 error = SET_ENDIAN(me, arg2);
2143                 break;
2144         case PR_GET_SECCOMP:
2145                 error = prctl_get_seccomp();
2146                 break;
2147         case PR_SET_SECCOMP:
2148                 error = prctl_set_seccomp(arg2, (char __user *)arg3);
2149                 break;
2150         case PR_GET_TSC:
2151                 error = GET_TSC_CTL(arg2);
2152                 break;
2153         case PR_SET_TSC:
2154                 error = SET_TSC_CTL(arg2);
2155                 break;
2156         case PR_TASK_PERF_EVENTS_DISABLE:
2157                 error = perf_event_task_disable();
2158                 break;
2159         case PR_TASK_PERF_EVENTS_ENABLE:
2160                 error = perf_event_task_enable();
2161                 break;
2162         case PR_GET_TIMERSLACK:
2163                 if (current->timer_slack_ns > ULONG_MAX)
2164                         error = ULONG_MAX;
2165                 else
2166                         error = current->timer_slack_ns;
2167                 break;
2168         case PR_SET_TIMERSLACK:
2169                 if (arg2 <= 0)
2170                         current->timer_slack_ns =
2171                                         current->default_timer_slack_ns;
2172                 else
2173                         current->timer_slack_ns = arg2;
2174                 break;
2175         case PR_MCE_KILL:
2176                 if (arg4 | arg5)
2177                         return -EINVAL;
2178                 switch (arg2) {
2179                 case PR_MCE_KILL_CLEAR:
2180                         if (arg3 != 0)
2181                                 return -EINVAL;
2182                         current->flags &= ~PF_MCE_PROCESS;
2183                         break;
2184                 case PR_MCE_KILL_SET:
2185                         current->flags |= PF_MCE_PROCESS;
2186                         if (arg3 == PR_MCE_KILL_EARLY)
2187                                 current->flags |= PF_MCE_EARLY;
2188                         else if (arg3 == PR_MCE_KILL_LATE)
2189                                 current->flags &= ~PF_MCE_EARLY;
2190                         else if (arg3 == PR_MCE_KILL_DEFAULT)
2191                                 current->flags &=
2192                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
2193                         else
2194                                 return -EINVAL;
2195                         break;
2196                 default:
2197                         return -EINVAL;
2198                 }
2199                 break;
2200         case PR_MCE_KILL_GET:
2201                 if (arg2 | arg3 | arg4 | arg5)
2202                         return -EINVAL;
2203                 if (current->flags & PF_MCE_PROCESS)
2204                         error = (current->flags & PF_MCE_EARLY) ?
2205                                 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2206                 else
2207                         error = PR_MCE_KILL_DEFAULT;
2208                 break;
2209         case PR_SET_MM:
2210                 error = prctl_set_mm(arg2, arg3, arg4, arg5);
2211                 break;
2212         case PR_GET_TID_ADDRESS:
2213                 error = prctl_get_tid_address(me, (int __user **)arg2);
2214                 break;
2215         case PR_SET_CHILD_SUBREAPER:
2216                 me->signal->is_child_subreaper = !!arg2;
2217                 break;
2218         case PR_GET_CHILD_SUBREAPER:
2219                 error = put_user(me->signal->is_child_subreaper,
2220                                  (int __user *)arg2);
2221                 break;
2222         case PR_SET_NO_NEW_PRIVS:
2223                 if (arg2 != 1 || arg3 || arg4 || arg5)
2224                         return -EINVAL;
2225 
2226                 task_set_no_new_privs(current);
2227                 break;
2228         case PR_GET_NO_NEW_PRIVS:
2229                 if (arg2 || arg3 || arg4 || arg5)
2230                         return -EINVAL;
2231                 return task_no_new_privs(current) ? 1 : 0;
2232         case PR_GET_THP_DISABLE:
2233                 if (arg2 || arg3 || arg4 || arg5)
2234                         return -EINVAL;
2235                 error = !!(me->mm->def_flags & VM_NOHUGEPAGE);
2236                 break;
2237         case PR_SET_THP_DISABLE:
2238                 if (arg3 || arg4 || arg5)
2239                         return -EINVAL;
2240                 if (down_write_killable(&me->mm->mmap_sem))
2241                         return -EINTR;
2242                 if (arg2)
2243                         me->mm->def_flags |= VM_NOHUGEPAGE;
2244                 else
2245                         me->mm->def_flags &= ~VM_NOHUGEPAGE;
2246                 up_write(&me->mm->mmap_sem);
2247                 break;
2248         case PR_MPX_ENABLE_MANAGEMENT:
2249                 if (arg2 || arg3 || arg4 || arg5)
2250                         return -EINVAL;
2251                 error = MPX_ENABLE_MANAGEMENT();
2252                 break;
2253         case PR_MPX_DISABLE_MANAGEMENT:
2254                 if (arg2 || arg3 || arg4 || arg5)
2255                         return -EINVAL;
2256                 error = MPX_DISABLE_MANAGEMENT();
2257                 break;
2258         case PR_SET_FP_MODE:
2259                 error = SET_FP_MODE(me, arg2);
2260                 break;
2261         case PR_GET_FP_MODE:
2262                 error = GET_FP_MODE(me);
2263                 break;
2264         default:
2265                 error = -EINVAL;
2266                 break;
2267         }
2268         return error;
2269 }
2270 
2271 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2272                 struct getcpu_cache __user *, unused)
2273 {
2274         int err = 0;
2275         int cpu = raw_smp_processor_id();
2276 
2277         if (cpup)
2278                 err |= put_user(cpu, cpup);
2279         if (nodep)
2280                 err |= put_user(cpu_to_node(cpu), nodep);
2281         return err ? -EFAULT : 0;
2282 }
2283 
2284 /**
2285  * do_sysinfo - fill in sysinfo struct
2286  * @info: pointer to buffer to fill
2287  */
2288 static int do_sysinfo(struct sysinfo *info)
2289 {
2290         unsigned long mem_total, sav_total;
2291         unsigned int mem_unit, bitcount;
2292         struct timespec tp;
2293 
2294         memset(info, 0, sizeof(struct sysinfo));
2295 
2296         get_monotonic_boottime(&tp);
2297         info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
2298 
2299         get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
2300 
2301         info->procs = nr_threads;
2302 
2303         si_meminfo(info);
2304         si_swapinfo(info);
2305 
2306         /*
2307          * If the sum of all the available memory (i.e. ram + swap)
2308          * is less than can be stored in a 32 bit unsigned long then
2309          * we can be binary compatible with 2.2.x kernels.  If not,
2310          * well, in that case 2.2.x was broken anyways...
2311          *
2312          *  -Erik Andersen <andersee@debian.org>
2313          */
2314 
2315         mem_total = info->totalram + info->totalswap;
2316         if (mem_total < info->totalram || mem_total < info->totalswap)
2317                 goto out;
2318         bitcount = 0;
2319         mem_unit = info->mem_unit;
2320         while (mem_unit > 1) {
2321                 bitcount++;
2322                 mem_unit >>= 1;
2323                 sav_total = mem_total;
2324                 mem_total <<= 1;
2325                 if (mem_total < sav_total)
2326                         goto out;
2327         }
2328 
2329         /*
2330          * If mem_total did not overflow, multiply all memory values by
2331          * info->mem_unit and set it to 1.  This leaves things compatible
2332          * with 2.2.x, and also retains compatibility with earlier 2.4.x
2333          * kernels...
2334          */
2335 
2336         info->mem_unit = 1;
2337         info->totalram <<= bitcount;
2338         info->freeram <<= bitcount;
2339         info->sharedram <<= bitcount;
2340         info->bufferram <<= bitcount;
2341         info->totalswap <<= bitcount;
2342         info->freeswap <<= bitcount;
2343         info->totalhigh <<= bitcount;
2344         info->freehigh <<= bitcount;
2345 
2346 out:
2347         return 0;
2348 }
2349 
2350 SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
2351 {
2352         struct sysinfo val;
2353 
2354         do_sysinfo(&val);
2355 
2356         if (copy_to_user(info, &val, sizeof(struct sysinfo)))
2357                 return -EFAULT;
2358 
2359         return 0;
2360 }
2361 
2362 #ifdef CONFIG_COMPAT
2363 struct compat_sysinfo {
2364         s32 uptime;
2365         u32 loads[3];
2366         u32 totalram;
2367         u32 freeram;
2368         u32 sharedram;
2369         u32 bufferram;
2370         u32 totalswap;
2371         u32 freeswap;
2372         u16 procs;
2373         u16 pad;
2374         u32 totalhigh;
2375         u32 freehigh;
2376         u32 mem_unit;
2377         char _f[20-2*sizeof(u32)-sizeof(int)];
2378 };
2379 
2380 COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info)
2381 {
2382         struct sysinfo s;
2383 
2384         do_sysinfo(&s);
2385 
2386         /* Check to see if any memory value is too large for 32-bit and scale
2387          *  down if needed
2388          */
2389         if (upper_32_bits(s.totalram) || upper_32_bits(s.totalswap)) {
2390                 int bitcount = 0;
2391 
2392                 while (s.mem_unit < PAGE_SIZE) {
2393                         s.mem_unit <<= 1;
2394                         bitcount++;
2395                 }
2396 
2397                 s.totalram >>= bitcount;
2398                 s.freeram >>= bitcount;
2399                 s.sharedram >>= bitcount;
2400                 s.bufferram >>= bitcount;
2401                 s.totalswap >>= bitcount;
2402                 s.freeswap >>= bitcount;
2403                 s.totalhigh >>= bitcount;
2404                 s.freehigh >>= bitcount;
2405         }
2406 
2407         if (!access_ok(VERIFY_WRITE, info, sizeof(struct compat_sysinfo)) ||
2408             __put_user(s.uptime, &info->uptime) ||
2409             __put_user(s.loads[0], &info->loads[0]) ||
2410             __put_user(s.loads[1], &info->loads[1]) ||
2411             __put_user(s.loads[2], &info->loads[2]) ||
2412             __put_user(s.totalram, &info->totalram) ||
2413             __put_user(s.freeram, &info->freeram) ||
2414             __put_user(s.sharedram, &info->sharedram) ||
2415             __put_user(s.bufferram, &info->bufferram) ||
2416             __put_user(s.totalswap, &info->totalswap) ||
2417             __put_user(s.freeswap, &info->freeswap) ||
2418             __put_user(s.procs, &info->procs) ||
2419             __put_user(s.totalhigh, &info->totalhigh) ||
2420             __put_user(s.freehigh, &info->freehigh) ||
2421             __put_user(s.mem_unit, &info->mem_unit))
2422                 return -EFAULT;
2423 
2424         return 0;
2425 }
2426 #endif /* CONFIG_COMPAT */
2427 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us