xref: /openbmc/linux/kernel/sys.c (revision e7f127b2)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/kernel/sys.c
4  *
5  *  Copyright (C) 1991, 1992  Linus Torvalds
6  */
7 
8 #include <linux/export.h>
9 #include <linux/mm.h>
10 #include <linux/utsname.h>
11 #include <linux/mman.h>
12 #include <linux/reboot.h>
13 #include <linux/prctl.h>
14 #include <linux/highuid.h>
15 #include <linux/fs.h>
16 #include <linux/kmod.h>
17 #include <linux/perf_event.h>
18 #include <linux/resource.h>
19 #include <linux/kernel.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/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 #include <linux/syscall_user_dispatch.h>
45 
46 #include <linux/compat.h>
47 #include <linux/syscalls.h>
48 #include <linux/kprobes.h>
49 #include <linux/user_namespace.h>
50 #include <linux/time_namespace.h>
51 #include <linux/binfmts.h>
52 
53 #include <linux/sched.h>
54 #include <linux/sched/autogroup.h>
55 #include <linux/sched/loadavg.h>
56 #include <linux/sched/stat.h>
57 #include <linux/sched/mm.h>
58 #include <linux/sched/coredump.h>
59 #include <linux/sched/task.h>
60 #include <linux/sched/cputime.h>
61 #include <linux/rcupdate.h>
62 #include <linux/uidgid.h>
63 #include <linux/cred.h>
64 
65 #include <linux/nospec.h>
66 
67 #include <linux/kmsg_dump.h>
68 /* Move somewhere else to avoid recompiling? */
69 #include <generated/utsrelease.h>
70 
71 #include <linux/uaccess.h>
72 #include <asm/io.h>
73 #include <asm/unistd.h>
74 
75 #include "uid16.h"
76 
77 #ifndef SET_UNALIGN_CTL
78 # define SET_UNALIGN_CTL(a, b)	(-EINVAL)
79 #endif
80 #ifndef GET_UNALIGN_CTL
81 # define GET_UNALIGN_CTL(a, b)	(-EINVAL)
82 #endif
83 #ifndef SET_FPEMU_CTL
84 # define SET_FPEMU_CTL(a, b)	(-EINVAL)
85 #endif
86 #ifndef GET_FPEMU_CTL
87 # define GET_FPEMU_CTL(a, b)	(-EINVAL)
88 #endif
89 #ifndef SET_FPEXC_CTL
90 # define SET_FPEXC_CTL(a, b)	(-EINVAL)
91 #endif
92 #ifndef GET_FPEXC_CTL
93 # define GET_FPEXC_CTL(a, b)	(-EINVAL)
94 #endif
95 #ifndef GET_ENDIAN
96 # define GET_ENDIAN(a, b)	(-EINVAL)
97 #endif
98 #ifndef SET_ENDIAN
99 # define SET_ENDIAN(a, b)	(-EINVAL)
100 #endif
101 #ifndef GET_TSC_CTL
102 # define GET_TSC_CTL(a)		(-EINVAL)
103 #endif
104 #ifndef SET_TSC_CTL
105 # define SET_TSC_CTL(a)		(-EINVAL)
106 #endif
107 #ifndef GET_FP_MODE
108 # define GET_FP_MODE(a)		(-EINVAL)
109 #endif
110 #ifndef SET_FP_MODE
111 # define SET_FP_MODE(a,b)	(-EINVAL)
112 #endif
113 #ifndef SVE_SET_VL
114 # define SVE_SET_VL(a)		(-EINVAL)
115 #endif
116 #ifndef SVE_GET_VL
117 # define SVE_GET_VL()		(-EINVAL)
118 #endif
119 #ifndef PAC_RESET_KEYS
120 # define PAC_RESET_KEYS(a, b)	(-EINVAL)
121 #endif
122 #ifndef PAC_SET_ENABLED_KEYS
123 # define PAC_SET_ENABLED_KEYS(a, b, c)	(-EINVAL)
124 #endif
125 #ifndef PAC_GET_ENABLED_KEYS
126 # define PAC_GET_ENABLED_KEYS(a)	(-EINVAL)
127 #endif
128 #ifndef SET_TAGGED_ADDR_CTRL
129 # define SET_TAGGED_ADDR_CTRL(a)	(-EINVAL)
130 #endif
131 #ifndef GET_TAGGED_ADDR_CTRL
132 # define GET_TAGGED_ADDR_CTRL()		(-EINVAL)
133 #endif
134 
135 /*
136  * this is where the system-wide overflow UID and GID are defined, for
137  * architectures that now have 32-bit UID/GID but didn't in the past
138  */
139 
140 int overflowuid = DEFAULT_OVERFLOWUID;
141 int overflowgid = DEFAULT_OVERFLOWGID;
142 
143 EXPORT_SYMBOL(overflowuid);
144 EXPORT_SYMBOL(overflowgid);
145 
146 /*
147  * the same as above, but for filesystems which can only store a 16-bit
148  * UID and GID. as such, this is needed on all architectures
149  */
150 
151 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
152 int fs_overflowgid = DEFAULT_FS_OVERFLOWGID;
153 
154 EXPORT_SYMBOL(fs_overflowuid);
155 EXPORT_SYMBOL(fs_overflowgid);
156 
157 /*
158  * Returns true if current's euid is same as p's uid or euid,
159  * or has CAP_SYS_NICE to p's user_ns.
160  *
161  * Called with rcu_read_lock, creds are safe
162  */
163 static bool set_one_prio_perm(struct task_struct *p)
164 {
165 	const struct cred *cred = current_cred(), *pcred = __task_cred(p);
166 
167 	if (uid_eq(pcred->uid,  cred->euid) ||
168 	    uid_eq(pcred->euid, cred->euid))
169 		return true;
170 	if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
171 		return true;
172 	return false;
173 }
174 
175 /*
176  * set the priority of a task
177  * - the caller must hold the RCU read lock
178  */
179 static int set_one_prio(struct task_struct *p, int niceval, int error)
180 {
181 	int no_nice;
182 
183 	if (!set_one_prio_perm(p)) {
184 		error = -EPERM;
185 		goto out;
186 	}
187 	if (niceval < task_nice(p) && !can_nice(p, niceval)) {
188 		error = -EACCES;
189 		goto out;
190 	}
191 	no_nice = security_task_setnice(p, niceval);
192 	if (no_nice) {
193 		error = no_nice;
194 		goto out;
195 	}
196 	if (error == -ESRCH)
197 		error = 0;
198 	set_user_nice(p, niceval);
199 out:
200 	return error;
201 }
202 
203 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
204 {
205 	struct task_struct *g, *p;
206 	struct user_struct *user;
207 	const struct cred *cred = current_cred();
208 	int error = -EINVAL;
209 	struct pid *pgrp;
210 	kuid_t uid;
211 
212 	if (which > PRIO_USER || which < PRIO_PROCESS)
213 		goto out;
214 
215 	/* normalize: avoid signed division (rounding problems) */
216 	error = -ESRCH;
217 	if (niceval < MIN_NICE)
218 		niceval = MIN_NICE;
219 	if (niceval > MAX_NICE)
220 		niceval = MAX_NICE;
221 
222 	rcu_read_lock();
223 	switch (which) {
224 	case PRIO_PROCESS:
225 		if (who)
226 			p = find_task_by_vpid(who);
227 		else
228 			p = current;
229 		if (p)
230 			error = set_one_prio(p, niceval, error);
231 		break;
232 	case PRIO_PGRP:
233 		if (who)
234 			pgrp = find_vpid(who);
235 		else
236 			pgrp = task_pgrp(current);
237 		read_lock(&tasklist_lock);
238 		do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
239 			error = set_one_prio(p, niceval, error);
240 		} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
241 		read_unlock(&tasklist_lock);
242 		break;
243 	case PRIO_USER:
244 		uid = make_kuid(cred->user_ns, who);
245 		user = cred->user;
246 		if (!who)
247 			uid = cred->uid;
248 		else if (!uid_eq(uid, cred->uid)) {
249 			user = find_user(uid);
250 			if (!user)
251 				goto out_unlock;	/* No processes for this user */
252 		}
253 		for_each_process_thread(g, p) {
254 			if (uid_eq(task_uid(p), uid) && task_pid_vnr(p))
255 				error = set_one_prio(p, niceval, error);
256 		}
257 		if (!uid_eq(uid, cred->uid))
258 			free_uid(user);		/* For find_user() */
259 		break;
260 	}
261 out_unlock:
262 	rcu_read_unlock();
263 out:
264 	return error;
265 }
266 
267 /*
268  * Ugh. To avoid negative return values, "getpriority()" will
269  * not return the normal nice-value, but a negated value that
270  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
271  * to stay compatible.
272  */
273 SYSCALL_DEFINE2(getpriority, int, which, int, who)
274 {
275 	struct task_struct *g, *p;
276 	struct user_struct *user;
277 	const struct cred *cred = current_cred();
278 	long niceval, retval = -ESRCH;
279 	struct pid *pgrp;
280 	kuid_t uid;
281 
282 	if (which > PRIO_USER || which < PRIO_PROCESS)
283 		return -EINVAL;
284 
285 	rcu_read_lock();
286 	switch (which) {
287 	case PRIO_PROCESS:
288 		if (who)
289 			p = find_task_by_vpid(who);
290 		else
291 			p = current;
292 		if (p) {
293 			niceval = nice_to_rlimit(task_nice(p));
294 			if (niceval > retval)
295 				retval = niceval;
296 		}
297 		break;
298 	case PRIO_PGRP:
299 		if (who)
300 			pgrp = find_vpid(who);
301 		else
302 			pgrp = task_pgrp(current);
303 		read_lock(&tasklist_lock);
304 		do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
305 			niceval = nice_to_rlimit(task_nice(p));
306 			if (niceval > retval)
307 				retval = niceval;
308 		} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
309 		read_unlock(&tasklist_lock);
310 		break;
311 	case PRIO_USER:
312 		uid = make_kuid(cred->user_ns, who);
313 		user = cred->user;
314 		if (!who)
315 			uid = cred->uid;
316 		else if (!uid_eq(uid, cred->uid)) {
317 			user = find_user(uid);
318 			if (!user)
319 				goto out_unlock;	/* No processes for this user */
320 		}
321 		for_each_process_thread(g, p) {
322 			if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) {
323 				niceval = nice_to_rlimit(task_nice(p));
324 				if (niceval > retval)
325 					retval = niceval;
326 			}
327 		}
328 		if (!uid_eq(uid, cred->uid))
329 			free_uid(user);		/* for find_user() */
330 		break;
331 	}
332 out_unlock:
333 	rcu_read_unlock();
334 
335 	return retval;
336 }
337 
338 /*
339  * Unprivileged users may change the real gid to the effective gid
340  * or vice versa.  (BSD-style)
341  *
342  * If you set the real gid at all, or set the effective gid to a value not
343  * equal to the real gid, then the saved gid is set to the new effective gid.
344  *
345  * This makes it possible for a setgid program to completely drop its
346  * privileges, which is often a useful assertion to make when you are doing
347  * a security audit over a program.
348  *
349  * The general idea is that a program which uses just setregid() will be
350  * 100% compatible with BSD.  A program which uses just setgid() will be
351  * 100% compatible with POSIX with saved IDs.
352  *
353  * SMP: There are not races, the GIDs are checked only by filesystem
354  *      operations (as far as semantic preservation is concerned).
355  */
356 #ifdef CONFIG_MULTIUSER
357 long __sys_setregid(gid_t rgid, gid_t egid)
358 {
359 	struct user_namespace *ns = current_user_ns();
360 	const struct cred *old;
361 	struct cred *new;
362 	int retval;
363 	kgid_t krgid, kegid;
364 
365 	krgid = make_kgid(ns, rgid);
366 	kegid = make_kgid(ns, egid);
367 
368 	if ((rgid != (gid_t) -1) && !gid_valid(krgid))
369 		return -EINVAL;
370 	if ((egid != (gid_t) -1) && !gid_valid(kegid))
371 		return -EINVAL;
372 
373 	new = prepare_creds();
374 	if (!new)
375 		return -ENOMEM;
376 	old = current_cred();
377 
378 	retval = -EPERM;
379 	if (rgid != (gid_t) -1) {
380 		if (gid_eq(old->gid, krgid) ||
381 		    gid_eq(old->egid, krgid) ||
382 		    ns_capable_setid(old->user_ns, CAP_SETGID))
383 			new->gid = krgid;
384 		else
385 			goto error;
386 	}
387 	if (egid != (gid_t) -1) {
388 		if (gid_eq(old->gid, kegid) ||
389 		    gid_eq(old->egid, kegid) ||
390 		    gid_eq(old->sgid, kegid) ||
391 		    ns_capable_setid(old->user_ns, CAP_SETGID))
392 			new->egid = kegid;
393 		else
394 			goto error;
395 	}
396 
397 	if (rgid != (gid_t) -1 ||
398 	    (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
399 		new->sgid = new->egid;
400 	new->fsgid = new->egid;
401 
402 	retval = security_task_fix_setgid(new, old, LSM_SETID_RE);
403 	if (retval < 0)
404 		goto error;
405 
406 	return commit_creds(new);
407 
408 error:
409 	abort_creds(new);
410 	return retval;
411 }
412 
413 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
414 {
415 	return __sys_setregid(rgid, egid);
416 }
417 
418 /*
419  * setgid() is implemented like SysV w/ SAVED_IDS
420  *
421  * SMP: Same implicit races as above.
422  */
423 long __sys_setgid(gid_t gid)
424 {
425 	struct user_namespace *ns = current_user_ns();
426 	const struct cred *old;
427 	struct cred *new;
428 	int retval;
429 	kgid_t kgid;
430 
431 	kgid = make_kgid(ns, gid);
432 	if (!gid_valid(kgid))
433 		return -EINVAL;
434 
435 	new = prepare_creds();
436 	if (!new)
437 		return -ENOMEM;
438 	old = current_cred();
439 
440 	retval = -EPERM;
441 	if (ns_capable_setid(old->user_ns, CAP_SETGID))
442 		new->gid = new->egid = new->sgid = new->fsgid = kgid;
443 	else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
444 		new->egid = new->fsgid = kgid;
445 	else
446 		goto error;
447 
448 	retval = security_task_fix_setgid(new, old, LSM_SETID_ID);
449 	if (retval < 0)
450 		goto error;
451 
452 	return commit_creds(new);
453 
454 error:
455 	abort_creds(new);
456 	return retval;
457 }
458 
459 SYSCALL_DEFINE1(setgid, gid_t, gid)
460 {
461 	return __sys_setgid(gid);
462 }
463 
464 /*
465  * change the user struct in a credentials set to match the new UID
466  */
467 static int set_user(struct cred *new)
468 {
469 	struct user_struct *new_user;
470 
471 	new_user = alloc_uid(new->uid);
472 	if (!new_user)
473 		return -EAGAIN;
474 
475 	/*
476 	 * We don't fail in case of NPROC limit excess here because too many
477 	 * poorly written programs don't check set*uid() return code, assuming
478 	 * it never fails if called by root.  We may still enforce NPROC limit
479 	 * for programs doing set*uid()+execve() by harmlessly deferring the
480 	 * failure to the execve() stage.
481 	 */
482 	if (is_ucounts_overlimit(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) &&
483 			new_user != INIT_USER &&
484 			!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
485 		current->flags |= PF_NPROC_EXCEEDED;
486 	else
487 		current->flags &= ~PF_NPROC_EXCEEDED;
488 
489 	free_uid(new->user);
490 	new->user = new_user;
491 	return 0;
492 }
493 
494 /*
495  * Unprivileged users may change the real uid to the effective uid
496  * or vice versa.  (BSD-style)
497  *
498  * If you set the real uid at all, or set the effective uid to a value not
499  * equal to the real uid, then the saved uid is set to the new effective uid.
500  *
501  * This makes it possible for a setuid program to completely drop its
502  * privileges, which is often a useful assertion to make when you are doing
503  * a security audit over a program.
504  *
505  * The general idea is that a program which uses just setreuid() will be
506  * 100% compatible with BSD.  A program which uses just setuid() will be
507  * 100% compatible with POSIX with saved IDs.
508  */
509 long __sys_setreuid(uid_t ruid, uid_t euid)
510 {
511 	struct user_namespace *ns = current_user_ns();
512 	const struct cred *old;
513 	struct cred *new;
514 	int retval;
515 	kuid_t kruid, keuid;
516 
517 	kruid = make_kuid(ns, ruid);
518 	keuid = make_kuid(ns, euid);
519 
520 	if ((ruid != (uid_t) -1) && !uid_valid(kruid))
521 		return -EINVAL;
522 	if ((euid != (uid_t) -1) && !uid_valid(keuid))
523 		return -EINVAL;
524 
525 	new = prepare_creds();
526 	if (!new)
527 		return -ENOMEM;
528 	old = current_cred();
529 
530 	retval = -EPERM;
531 	if (ruid != (uid_t) -1) {
532 		new->uid = kruid;
533 		if (!uid_eq(old->uid, kruid) &&
534 		    !uid_eq(old->euid, kruid) &&
535 		    !ns_capable_setid(old->user_ns, CAP_SETUID))
536 			goto error;
537 	}
538 
539 	if (euid != (uid_t) -1) {
540 		new->euid = keuid;
541 		if (!uid_eq(old->uid, keuid) &&
542 		    !uid_eq(old->euid, keuid) &&
543 		    !uid_eq(old->suid, keuid) &&
544 		    !ns_capable_setid(old->user_ns, CAP_SETUID))
545 			goto error;
546 	}
547 
548 	if (!uid_eq(new->uid, old->uid)) {
549 		retval = set_user(new);
550 		if (retval < 0)
551 			goto error;
552 	}
553 	if (ruid != (uid_t) -1 ||
554 	    (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
555 		new->suid = new->euid;
556 	new->fsuid = new->euid;
557 
558 	retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
559 	if (retval < 0)
560 		goto error;
561 
562 	retval = set_cred_ucounts(new);
563 	if (retval < 0)
564 		goto error;
565 
566 	return commit_creds(new);
567 
568 error:
569 	abort_creds(new);
570 	return retval;
571 }
572 
573 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
574 {
575 	return __sys_setreuid(ruid, euid);
576 }
577 
578 /*
579  * setuid() is implemented like SysV with SAVED_IDS
580  *
581  * Note that SAVED_ID's is deficient in that a setuid root program
582  * like sendmail, for example, cannot set its uid to be a normal
583  * user and then switch back, because if you're root, setuid() sets
584  * the saved uid too.  If you don't like this, blame the bright people
585  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
586  * will allow a root program to temporarily drop privileges and be able to
587  * regain them by swapping the real and effective uid.
588  */
589 long __sys_setuid(uid_t uid)
590 {
591 	struct user_namespace *ns = current_user_ns();
592 	const struct cred *old;
593 	struct cred *new;
594 	int retval;
595 	kuid_t kuid;
596 
597 	kuid = make_kuid(ns, uid);
598 	if (!uid_valid(kuid))
599 		return -EINVAL;
600 
601 	new = prepare_creds();
602 	if (!new)
603 		return -ENOMEM;
604 	old = current_cred();
605 
606 	retval = -EPERM;
607 	if (ns_capable_setid(old->user_ns, CAP_SETUID)) {
608 		new->suid = new->uid = kuid;
609 		if (!uid_eq(kuid, old->uid)) {
610 			retval = set_user(new);
611 			if (retval < 0)
612 				goto error;
613 		}
614 	} else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
615 		goto error;
616 	}
617 
618 	new->fsuid = new->euid = kuid;
619 
620 	retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
621 	if (retval < 0)
622 		goto error;
623 
624 	retval = set_cred_ucounts(new);
625 	if (retval < 0)
626 		goto error;
627 
628 	return commit_creds(new);
629 
630 error:
631 	abort_creds(new);
632 	return retval;
633 }
634 
635 SYSCALL_DEFINE1(setuid, uid_t, uid)
636 {
637 	return __sys_setuid(uid);
638 }
639 
640 
641 /*
642  * This function implements a generic ability to update ruid, euid,
643  * and suid.  This allows you to implement the 4.4 compatible seteuid().
644  */
645 long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
646 {
647 	struct user_namespace *ns = current_user_ns();
648 	const struct cred *old;
649 	struct cred *new;
650 	int retval;
651 	kuid_t kruid, keuid, ksuid;
652 
653 	kruid = make_kuid(ns, ruid);
654 	keuid = make_kuid(ns, euid);
655 	ksuid = make_kuid(ns, suid);
656 
657 	if ((ruid != (uid_t) -1) && !uid_valid(kruid))
658 		return -EINVAL;
659 
660 	if ((euid != (uid_t) -1) && !uid_valid(keuid))
661 		return -EINVAL;
662 
663 	if ((suid != (uid_t) -1) && !uid_valid(ksuid))
664 		return -EINVAL;
665 
666 	new = prepare_creds();
667 	if (!new)
668 		return -ENOMEM;
669 
670 	old = current_cred();
671 
672 	retval = -EPERM;
673 	if (!ns_capable_setid(old->user_ns, CAP_SETUID)) {
674 		if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
675 		    !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
676 			goto error;
677 		if (euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
678 		    !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
679 			goto error;
680 		if (suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
681 		    !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
682 			goto error;
683 	}
684 
685 	if (ruid != (uid_t) -1) {
686 		new->uid = kruid;
687 		if (!uid_eq(kruid, old->uid)) {
688 			retval = set_user(new);
689 			if (retval < 0)
690 				goto error;
691 		}
692 	}
693 	if (euid != (uid_t) -1)
694 		new->euid = keuid;
695 	if (suid != (uid_t) -1)
696 		new->suid = ksuid;
697 	new->fsuid = new->euid;
698 
699 	retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
700 	if (retval < 0)
701 		goto error;
702 
703 	retval = set_cred_ucounts(new);
704 	if (retval < 0)
705 		goto error;
706 
707 	return commit_creds(new);
708 
709 error:
710 	abort_creds(new);
711 	return retval;
712 }
713 
714 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
715 {
716 	return __sys_setresuid(ruid, euid, suid);
717 }
718 
719 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
720 {
721 	const struct cred *cred = current_cred();
722 	int retval;
723 	uid_t ruid, euid, suid;
724 
725 	ruid = from_kuid_munged(cred->user_ns, cred->uid);
726 	euid = from_kuid_munged(cred->user_ns, cred->euid);
727 	suid = from_kuid_munged(cred->user_ns, cred->suid);
728 
729 	retval = put_user(ruid, ruidp);
730 	if (!retval) {
731 		retval = put_user(euid, euidp);
732 		if (!retval)
733 			return put_user(suid, suidp);
734 	}
735 	return retval;
736 }
737 
738 /*
739  * Same as above, but for rgid, egid, sgid.
740  */
741 long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
742 {
743 	struct user_namespace *ns = current_user_ns();
744 	const struct cred *old;
745 	struct cred *new;
746 	int retval;
747 	kgid_t krgid, kegid, ksgid;
748 
749 	krgid = make_kgid(ns, rgid);
750 	kegid = make_kgid(ns, egid);
751 	ksgid = make_kgid(ns, sgid);
752 
753 	if ((rgid != (gid_t) -1) && !gid_valid(krgid))
754 		return -EINVAL;
755 	if ((egid != (gid_t) -1) && !gid_valid(kegid))
756 		return -EINVAL;
757 	if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
758 		return -EINVAL;
759 
760 	new = prepare_creds();
761 	if (!new)
762 		return -ENOMEM;
763 	old = current_cred();
764 
765 	retval = -EPERM;
766 	if (!ns_capable_setid(old->user_ns, CAP_SETGID)) {
767 		if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
768 		    !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
769 			goto error;
770 		if (egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
771 		    !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
772 			goto error;
773 		if (sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
774 		    !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
775 			goto error;
776 	}
777 
778 	if (rgid != (gid_t) -1)
779 		new->gid = krgid;
780 	if (egid != (gid_t) -1)
781 		new->egid = kegid;
782 	if (sgid != (gid_t) -1)
783 		new->sgid = ksgid;
784 	new->fsgid = new->egid;
785 
786 	retval = security_task_fix_setgid(new, old, LSM_SETID_RES);
787 	if (retval < 0)
788 		goto error;
789 
790 	return commit_creds(new);
791 
792 error:
793 	abort_creds(new);
794 	return retval;
795 }
796 
797 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
798 {
799 	return __sys_setresgid(rgid, egid, sgid);
800 }
801 
802 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
803 {
804 	const struct cred *cred = current_cred();
805 	int retval;
806 	gid_t rgid, egid, sgid;
807 
808 	rgid = from_kgid_munged(cred->user_ns, cred->gid);
809 	egid = from_kgid_munged(cred->user_ns, cred->egid);
810 	sgid = from_kgid_munged(cred->user_ns, cred->sgid);
811 
812 	retval = put_user(rgid, rgidp);
813 	if (!retval) {
814 		retval = put_user(egid, egidp);
815 		if (!retval)
816 			retval = put_user(sgid, sgidp);
817 	}
818 
819 	return retval;
820 }
821 
822 
823 /*
824  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
825  * is used for "access()" and for the NFS daemon (letting nfsd stay at
826  * whatever uid it wants to). It normally shadows "euid", except when
827  * explicitly set by setfsuid() or for access..
828  */
829 long __sys_setfsuid(uid_t uid)
830 {
831 	const struct cred *old;
832 	struct cred *new;
833 	uid_t old_fsuid;
834 	kuid_t kuid;
835 
836 	old = current_cred();
837 	old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
838 
839 	kuid = make_kuid(old->user_ns, uid);
840 	if (!uid_valid(kuid))
841 		return old_fsuid;
842 
843 	new = prepare_creds();
844 	if (!new)
845 		return old_fsuid;
846 
847 	if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
848 	    uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
849 	    ns_capable_setid(old->user_ns, CAP_SETUID)) {
850 		if (!uid_eq(kuid, old->fsuid)) {
851 			new->fsuid = kuid;
852 			if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
853 				goto change_okay;
854 		}
855 	}
856 
857 	abort_creds(new);
858 	return old_fsuid;
859 
860 change_okay:
861 	commit_creds(new);
862 	return old_fsuid;
863 }
864 
865 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
866 {
867 	return __sys_setfsuid(uid);
868 }
869 
870 /*
871  * Samma på svenska..
872  */
873 long __sys_setfsgid(gid_t gid)
874 {
875 	const struct cred *old;
876 	struct cred *new;
877 	gid_t old_fsgid;
878 	kgid_t kgid;
879 
880 	old = current_cred();
881 	old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
882 
883 	kgid = make_kgid(old->user_ns, gid);
884 	if (!gid_valid(kgid))
885 		return old_fsgid;
886 
887 	new = prepare_creds();
888 	if (!new)
889 		return old_fsgid;
890 
891 	if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
892 	    gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
893 	    ns_capable_setid(old->user_ns, CAP_SETGID)) {
894 		if (!gid_eq(kgid, old->fsgid)) {
895 			new->fsgid = kgid;
896 			if (security_task_fix_setgid(new,old,LSM_SETID_FS) == 0)
897 				goto change_okay;
898 		}
899 	}
900 
901 	abort_creds(new);
902 	return old_fsgid;
903 
904 change_okay:
905 	commit_creds(new);
906 	return old_fsgid;
907 }
908 
909 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
910 {
911 	return __sys_setfsgid(gid);
912 }
913 #endif /* CONFIG_MULTIUSER */
914 
915 /**
916  * sys_getpid - return the thread group id of the current process
917  *
918  * Note, despite the name, this returns the tgid not the pid.  The tgid and
919  * the pid are identical unless CLONE_THREAD was specified on clone() in
920  * which case the tgid is the same in all threads of the same group.
921  *
922  * This is SMP safe as current->tgid does not change.
923  */
924 SYSCALL_DEFINE0(getpid)
925 {
926 	return task_tgid_vnr(current);
927 }
928 
929 /* Thread ID - the internal kernel "pid" */
930 SYSCALL_DEFINE0(gettid)
931 {
932 	return task_pid_vnr(current);
933 }
934 
935 /*
936  * Accessing ->real_parent is not SMP-safe, it could
937  * change from under us. However, we can use a stale
938  * value of ->real_parent under rcu_read_lock(), see
939  * release_task()->call_rcu(delayed_put_task_struct).
940  */
941 SYSCALL_DEFINE0(getppid)
942 {
943 	int pid;
944 
945 	rcu_read_lock();
946 	pid = task_tgid_vnr(rcu_dereference(current->real_parent));
947 	rcu_read_unlock();
948 
949 	return pid;
950 }
951 
952 SYSCALL_DEFINE0(getuid)
953 {
954 	/* Only we change this so SMP safe */
955 	return from_kuid_munged(current_user_ns(), current_uid());
956 }
957 
958 SYSCALL_DEFINE0(geteuid)
959 {
960 	/* Only we change this so SMP safe */
961 	return from_kuid_munged(current_user_ns(), current_euid());
962 }
963 
964 SYSCALL_DEFINE0(getgid)
965 {
966 	/* Only we change this so SMP safe */
967 	return from_kgid_munged(current_user_ns(), current_gid());
968 }
969 
970 SYSCALL_DEFINE0(getegid)
971 {
972 	/* Only we change this so SMP safe */
973 	return from_kgid_munged(current_user_ns(), current_egid());
974 }
975 
976 static void do_sys_times(struct tms *tms)
977 {
978 	u64 tgutime, tgstime, cutime, cstime;
979 
980 	thread_group_cputime_adjusted(current, &tgutime, &tgstime);
981 	cutime = current->signal->cutime;
982 	cstime = current->signal->cstime;
983 	tms->tms_utime = nsec_to_clock_t(tgutime);
984 	tms->tms_stime = nsec_to_clock_t(tgstime);
985 	tms->tms_cutime = nsec_to_clock_t(cutime);
986 	tms->tms_cstime = nsec_to_clock_t(cstime);
987 }
988 
989 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
990 {
991 	if (tbuf) {
992 		struct tms tmp;
993 
994 		do_sys_times(&tmp);
995 		if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
996 			return -EFAULT;
997 	}
998 	force_successful_syscall_return();
999 	return (long) jiffies_64_to_clock_t(get_jiffies_64());
1000 }
1001 
1002 #ifdef CONFIG_COMPAT
1003 static compat_clock_t clock_t_to_compat_clock_t(clock_t x)
1004 {
1005 	return compat_jiffies_to_clock_t(clock_t_to_jiffies(x));
1006 }
1007 
1008 COMPAT_SYSCALL_DEFINE1(times, struct compat_tms __user *, tbuf)
1009 {
1010 	if (tbuf) {
1011 		struct tms tms;
1012 		struct compat_tms tmp;
1013 
1014 		do_sys_times(&tms);
1015 		/* Convert our struct tms to the compat version. */
1016 		tmp.tms_utime = clock_t_to_compat_clock_t(tms.tms_utime);
1017 		tmp.tms_stime = clock_t_to_compat_clock_t(tms.tms_stime);
1018 		tmp.tms_cutime = clock_t_to_compat_clock_t(tms.tms_cutime);
1019 		tmp.tms_cstime = clock_t_to_compat_clock_t(tms.tms_cstime);
1020 		if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
1021 			return -EFAULT;
1022 	}
1023 	force_successful_syscall_return();
1024 	return compat_jiffies_to_clock_t(jiffies);
1025 }
1026 #endif
1027 
1028 /*
1029  * This needs some heavy checking ...
1030  * I just haven't the stomach for it. I also don't fully
1031  * understand sessions/pgrp etc. Let somebody who does explain it.
1032  *
1033  * OK, I think I have the protection semantics right.... this is really
1034  * only important on a multi-user system anyway, to make sure one user
1035  * can't send a signal to a process owned by another.  -TYT, 12/12/91
1036  *
1037  * !PF_FORKNOEXEC check to conform completely to POSIX.
1038  */
1039 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1040 {
1041 	struct task_struct *p;
1042 	struct task_struct *group_leader = current->group_leader;
1043 	struct pid *pgrp;
1044 	int err;
1045 
1046 	if (!pid)
1047 		pid = task_pid_vnr(group_leader);
1048 	if (!pgid)
1049 		pgid = pid;
1050 	if (pgid < 0)
1051 		return -EINVAL;
1052 	rcu_read_lock();
1053 
1054 	/* From this point forward we keep holding onto the tasklist lock
1055 	 * so that our parent does not change from under us. -DaveM
1056 	 */
1057 	write_lock_irq(&tasklist_lock);
1058 
1059 	err = -ESRCH;
1060 	p = find_task_by_vpid(pid);
1061 	if (!p)
1062 		goto out;
1063 
1064 	err = -EINVAL;
1065 	if (!thread_group_leader(p))
1066 		goto out;
1067 
1068 	if (same_thread_group(p->real_parent, group_leader)) {
1069 		err = -EPERM;
1070 		if (task_session(p) != task_session(group_leader))
1071 			goto out;
1072 		err = -EACCES;
1073 		if (!(p->flags & PF_FORKNOEXEC))
1074 			goto out;
1075 	} else {
1076 		err = -ESRCH;
1077 		if (p != group_leader)
1078 			goto out;
1079 	}
1080 
1081 	err = -EPERM;
1082 	if (p->signal->leader)
1083 		goto out;
1084 
1085 	pgrp = task_pid(p);
1086 	if (pgid != pid) {
1087 		struct task_struct *g;
1088 
1089 		pgrp = find_vpid(pgid);
1090 		g = pid_task(pgrp, PIDTYPE_PGID);
1091 		if (!g || task_session(g) != task_session(group_leader))
1092 			goto out;
1093 	}
1094 
1095 	err = security_task_setpgid(p, pgid);
1096 	if (err)
1097 		goto out;
1098 
1099 	if (task_pgrp(p) != pgrp)
1100 		change_pid(p, PIDTYPE_PGID, pgrp);
1101 
1102 	err = 0;
1103 out:
1104 	/* All paths lead to here, thus we are safe. -DaveM */
1105 	write_unlock_irq(&tasklist_lock);
1106 	rcu_read_unlock();
1107 	return err;
1108 }
1109 
1110 static int do_getpgid(pid_t pid)
1111 {
1112 	struct task_struct *p;
1113 	struct pid *grp;
1114 	int retval;
1115 
1116 	rcu_read_lock();
1117 	if (!pid)
1118 		grp = task_pgrp(current);
1119 	else {
1120 		retval = -ESRCH;
1121 		p = find_task_by_vpid(pid);
1122 		if (!p)
1123 			goto out;
1124 		grp = task_pgrp(p);
1125 		if (!grp)
1126 			goto out;
1127 
1128 		retval = security_task_getpgid(p);
1129 		if (retval)
1130 			goto out;
1131 	}
1132 	retval = pid_vnr(grp);
1133 out:
1134 	rcu_read_unlock();
1135 	return retval;
1136 }
1137 
1138 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1139 {
1140 	return do_getpgid(pid);
1141 }
1142 
1143 #ifdef __ARCH_WANT_SYS_GETPGRP
1144 
1145 SYSCALL_DEFINE0(getpgrp)
1146 {
1147 	return do_getpgid(0);
1148 }
1149 
1150 #endif
1151 
1152 SYSCALL_DEFINE1(getsid, pid_t, pid)
1153 {
1154 	struct task_struct *p;
1155 	struct pid *sid;
1156 	int retval;
1157 
1158 	rcu_read_lock();
1159 	if (!pid)
1160 		sid = task_session(current);
1161 	else {
1162 		retval = -ESRCH;
1163 		p = find_task_by_vpid(pid);
1164 		if (!p)
1165 			goto out;
1166 		sid = task_session(p);
1167 		if (!sid)
1168 			goto out;
1169 
1170 		retval = security_task_getsid(p);
1171 		if (retval)
1172 			goto out;
1173 	}
1174 	retval = pid_vnr(sid);
1175 out:
1176 	rcu_read_unlock();
1177 	return retval;
1178 }
1179 
1180 static void set_special_pids(struct pid *pid)
1181 {
1182 	struct task_struct *curr = current->group_leader;
1183 
1184 	if (task_session(curr) != pid)
1185 		change_pid(curr, PIDTYPE_SID, pid);
1186 
1187 	if (task_pgrp(curr) != pid)
1188 		change_pid(curr, PIDTYPE_PGID, pid);
1189 }
1190 
1191 int ksys_setsid(void)
1192 {
1193 	struct task_struct *group_leader = current->group_leader;
1194 	struct pid *sid = task_pid(group_leader);
1195 	pid_t session = pid_vnr(sid);
1196 	int err = -EPERM;
1197 
1198 	write_lock_irq(&tasklist_lock);
1199 	/* Fail if I am already a session leader */
1200 	if (group_leader->signal->leader)
1201 		goto out;
1202 
1203 	/* Fail if a process group id already exists that equals the
1204 	 * proposed session id.
1205 	 */
1206 	if (pid_task(sid, PIDTYPE_PGID))
1207 		goto out;
1208 
1209 	group_leader->signal->leader = 1;
1210 	set_special_pids(sid);
1211 
1212 	proc_clear_tty(group_leader);
1213 
1214 	err = session;
1215 out:
1216 	write_unlock_irq(&tasklist_lock);
1217 	if (err > 0) {
1218 		proc_sid_connector(group_leader);
1219 		sched_autogroup_create_attach(group_leader);
1220 	}
1221 	return err;
1222 }
1223 
1224 SYSCALL_DEFINE0(setsid)
1225 {
1226 	return ksys_setsid();
1227 }
1228 
1229 DECLARE_RWSEM(uts_sem);
1230 
1231 #ifdef COMPAT_UTS_MACHINE
1232 #define override_architecture(name) \
1233 	(personality(current->personality) == PER_LINUX32 && \
1234 	 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1235 		      sizeof(COMPAT_UTS_MACHINE)))
1236 #else
1237 #define override_architecture(name)	0
1238 #endif
1239 
1240 /*
1241  * Work around broken programs that cannot handle "Linux 3.0".
1242  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1243  * And we map 4.x and later versions to 2.6.60+x, so 4.0/5.0/6.0/... would be
1244  * 2.6.60.
1245  */
1246 static int override_release(char __user *release, size_t len)
1247 {
1248 	int ret = 0;
1249 
1250 	if (current->personality & UNAME26) {
1251 		const char *rest = UTS_RELEASE;
1252 		char buf[65] = { 0 };
1253 		int ndots = 0;
1254 		unsigned v;
1255 		size_t copy;
1256 
1257 		while (*rest) {
1258 			if (*rest == '.' && ++ndots >= 3)
1259 				break;
1260 			if (!isdigit(*rest) && *rest != '.')
1261 				break;
1262 			rest++;
1263 		}
1264 		v = LINUX_VERSION_PATCHLEVEL + 60;
1265 		copy = clamp_t(size_t, len, 1, sizeof(buf));
1266 		copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
1267 		ret = copy_to_user(release, buf, copy + 1);
1268 	}
1269 	return ret;
1270 }
1271 
1272 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1273 {
1274 	struct new_utsname tmp;
1275 
1276 	down_read(&uts_sem);
1277 	memcpy(&tmp, utsname(), sizeof(tmp));
1278 	up_read(&uts_sem);
1279 	if (copy_to_user(name, &tmp, sizeof(tmp)))
1280 		return -EFAULT;
1281 
1282 	if (override_release(name->release, sizeof(name->release)))
1283 		return -EFAULT;
1284 	if (override_architecture(name))
1285 		return -EFAULT;
1286 	return 0;
1287 }
1288 
1289 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1290 /*
1291  * Old cruft
1292  */
1293 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1294 {
1295 	struct old_utsname tmp;
1296 
1297 	if (!name)
1298 		return -EFAULT;
1299 
1300 	down_read(&uts_sem);
1301 	memcpy(&tmp, utsname(), sizeof(tmp));
1302 	up_read(&uts_sem);
1303 	if (copy_to_user(name, &tmp, sizeof(tmp)))
1304 		return -EFAULT;
1305 
1306 	if (override_release(name->release, sizeof(name->release)))
1307 		return -EFAULT;
1308 	if (override_architecture(name))
1309 		return -EFAULT;
1310 	return 0;
1311 }
1312 
1313 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1314 {
1315 	struct oldold_utsname tmp;
1316 
1317 	if (!name)
1318 		return -EFAULT;
1319 
1320 	memset(&tmp, 0, sizeof(tmp));
1321 
1322 	down_read(&uts_sem);
1323 	memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
1324 	memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);
1325 	memcpy(&tmp.release, &utsname()->release, __OLD_UTS_LEN);
1326 	memcpy(&tmp.version, &utsname()->version, __OLD_UTS_LEN);
1327 	memcpy(&tmp.machine, &utsname()->machine, __OLD_UTS_LEN);
1328 	up_read(&uts_sem);
1329 	if (copy_to_user(name, &tmp, sizeof(tmp)))
1330 		return -EFAULT;
1331 
1332 	if (override_architecture(name))
1333 		return -EFAULT;
1334 	if (override_release(name->release, sizeof(name->release)))
1335 		return -EFAULT;
1336 	return 0;
1337 }
1338 #endif
1339 
1340 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1341 {
1342 	int errno;
1343 	char tmp[__NEW_UTS_LEN];
1344 
1345 	if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1346 		return -EPERM;
1347 
1348 	if (len < 0 || len > __NEW_UTS_LEN)
1349 		return -EINVAL;
1350 	errno = -EFAULT;
1351 	if (!copy_from_user(tmp, name, len)) {
1352 		struct new_utsname *u;
1353 
1354 		down_write(&uts_sem);
1355 		u = utsname();
1356 		memcpy(u->nodename, tmp, len);
1357 		memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1358 		errno = 0;
1359 		uts_proc_notify(UTS_PROC_HOSTNAME);
1360 		up_write(&uts_sem);
1361 	}
1362 	return errno;
1363 }
1364 
1365 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1366 
1367 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1368 {
1369 	int i;
1370 	struct new_utsname *u;
1371 	char tmp[__NEW_UTS_LEN + 1];
1372 
1373 	if (len < 0)
1374 		return -EINVAL;
1375 	down_read(&uts_sem);
1376 	u = utsname();
1377 	i = 1 + strlen(u->nodename);
1378 	if (i > len)
1379 		i = len;
1380 	memcpy(tmp, u->nodename, i);
1381 	up_read(&uts_sem);
1382 	if (copy_to_user(name, tmp, i))
1383 		return -EFAULT;
1384 	return 0;
1385 }
1386 
1387 #endif
1388 
1389 /*
1390  * Only setdomainname; getdomainname can be implemented by calling
1391  * uname()
1392  */
1393 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1394 {
1395 	int errno;
1396 	char tmp[__NEW_UTS_LEN];
1397 
1398 	if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1399 		return -EPERM;
1400 	if (len < 0 || len > __NEW_UTS_LEN)
1401 		return -EINVAL;
1402 
1403 	errno = -EFAULT;
1404 	if (!copy_from_user(tmp, name, len)) {
1405 		struct new_utsname *u;
1406 
1407 		down_write(&uts_sem);
1408 		u = utsname();
1409 		memcpy(u->domainname, tmp, len);
1410 		memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1411 		errno = 0;
1412 		uts_proc_notify(UTS_PROC_DOMAINNAME);
1413 		up_write(&uts_sem);
1414 	}
1415 	return errno;
1416 }
1417 
1418 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1419 {
1420 	struct rlimit value;
1421 	int ret;
1422 
1423 	ret = do_prlimit(current, resource, NULL, &value);
1424 	if (!ret)
1425 		ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1426 
1427 	return ret;
1428 }
1429 
1430 #ifdef CONFIG_COMPAT
1431 
1432 COMPAT_SYSCALL_DEFINE2(setrlimit, unsigned int, resource,
1433 		       struct compat_rlimit __user *, rlim)
1434 {
1435 	struct rlimit r;
1436 	struct compat_rlimit r32;
1437 
1438 	if (copy_from_user(&r32, rlim, sizeof(struct compat_rlimit)))
1439 		return -EFAULT;
1440 
1441 	if (r32.rlim_cur == COMPAT_RLIM_INFINITY)
1442 		r.rlim_cur = RLIM_INFINITY;
1443 	else
1444 		r.rlim_cur = r32.rlim_cur;
1445 	if (r32.rlim_max == COMPAT_RLIM_INFINITY)
1446 		r.rlim_max = RLIM_INFINITY;
1447 	else
1448 		r.rlim_max = r32.rlim_max;
1449 	return do_prlimit(current, resource, &r, NULL);
1450 }
1451 
1452 COMPAT_SYSCALL_DEFINE2(getrlimit, unsigned int, resource,
1453 		       struct compat_rlimit __user *, rlim)
1454 {
1455 	struct rlimit r;
1456 	int ret;
1457 
1458 	ret = do_prlimit(current, resource, NULL, &r);
1459 	if (!ret) {
1460 		struct compat_rlimit r32;
1461 		if (r.rlim_cur > COMPAT_RLIM_INFINITY)
1462 			r32.rlim_cur = COMPAT_RLIM_INFINITY;
1463 		else
1464 			r32.rlim_cur = r.rlim_cur;
1465 		if (r.rlim_max > COMPAT_RLIM_INFINITY)
1466 			r32.rlim_max = COMPAT_RLIM_INFINITY;
1467 		else
1468 			r32.rlim_max = r.rlim_max;
1469 
1470 		if (copy_to_user(rlim, &r32, sizeof(struct compat_rlimit)))
1471 			return -EFAULT;
1472 	}
1473 	return ret;
1474 }
1475 
1476 #endif
1477 
1478 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1479 
1480 /*
1481  *	Back compatibility for getrlimit. Needed for some apps.
1482  */
1483 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1484 		struct rlimit __user *, rlim)
1485 {
1486 	struct rlimit x;
1487 	if (resource >= RLIM_NLIMITS)
1488 		return -EINVAL;
1489 
1490 	resource = array_index_nospec(resource, RLIM_NLIMITS);
1491 	task_lock(current->group_leader);
1492 	x = current->signal->rlim[resource];
1493 	task_unlock(current->group_leader);
1494 	if (x.rlim_cur > 0x7FFFFFFF)
1495 		x.rlim_cur = 0x7FFFFFFF;
1496 	if (x.rlim_max > 0x7FFFFFFF)
1497 		x.rlim_max = 0x7FFFFFFF;
1498 	return copy_to_user(rlim, &x, sizeof(x)) ? -EFAULT : 0;
1499 }
1500 
1501 #ifdef CONFIG_COMPAT
1502 COMPAT_SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1503 		       struct compat_rlimit __user *, rlim)
1504 {
1505 	struct rlimit r;
1506 
1507 	if (resource >= RLIM_NLIMITS)
1508 		return -EINVAL;
1509 
1510 	resource = array_index_nospec(resource, RLIM_NLIMITS);
1511 	task_lock(current->group_leader);
1512 	r = current->signal->rlim[resource];
1513 	task_unlock(current->group_leader);
1514 	if (r.rlim_cur > 0x7FFFFFFF)
1515 		r.rlim_cur = 0x7FFFFFFF;
1516 	if (r.rlim_max > 0x7FFFFFFF)
1517 		r.rlim_max = 0x7FFFFFFF;
1518 
1519 	if (put_user(r.rlim_cur, &rlim->rlim_cur) ||
1520 	    put_user(r.rlim_max, &rlim->rlim_max))
1521 		return -EFAULT;
1522 	return 0;
1523 }
1524 #endif
1525 
1526 #endif
1527 
1528 static inline bool rlim64_is_infinity(__u64 rlim64)
1529 {
1530 #if BITS_PER_LONG < 64
1531 	return rlim64 >= ULONG_MAX;
1532 #else
1533 	return rlim64 == RLIM64_INFINITY;
1534 #endif
1535 }
1536 
1537 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1538 {
1539 	if (rlim->rlim_cur == RLIM_INFINITY)
1540 		rlim64->rlim_cur = RLIM64_INFINITY;
1541 	else
1542 		rlim64->rlim_cur = rlim->rlim_cur;
1543 	if (rlim->rlim_max == RLIM_INFINITY)
1544 		rlim64->rlim_max = RLIM64_INFINITY;
1545 	else
1546 		rlim64->rlim_max = rlim->rlim_max;
1547 }
1548 
1549 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1550 {
1551 	if (rlim64_is_infinity(rlim64->rlim_cur))
1552 		rlim->rlim_cur = RLIM_INFINITY;
1553 	else
1554 		rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1555 	if (rlim64_is_infinity(rlim64->rlim_max))
1556 		rlim->rlim_max = RLIM_INFINITY;
1557 	else
1558 		rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1559 }
1560 
1561 /* make sure you are allowed to change @tsk limits before calling this */
1562 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1563 		struct rlimit *new_rlim, struct rlimit *old_rlim)
1564 {
1565 	struct rlimit *rlim;
1566 	int retval = 0;
1567 
1568 	if (resource >= RLIM_NLIMITS)
1569 		return -EINVAL;
1570 	if (new_rlim) {
1571 		if (new_rlim->rlim_cur > new_rlim->rlim_max)
1572 			return -EINVAL;
1573 		if (resource == RLIMIT_NOFILE &&
1574 				new_rlim->rlim_max > sysctl_nr_open)
1575 			return -EPERM;
1576 	}
1577 
1578 	/* protect tsk->signal and tsk->sighand from disappearing */
1579 	read_lock(&tasklist_lock);
1580 	if (!tsk->sighand) {
1581 		retval = -ESRCH;
1582 		goto out;
1583 	}
1584 
1585 	rlim = tsk->signal->rlim + resource;
1586 	task_lock(tsk->group_leader);
1587 	if (new_rlim) {
1588 		/* Keep the capable check against init_user_ns until
1589 		   cgroups can contain all limits */
1590 		if (new_rlim->rlim_max > rlim->rlim_max &&
1591 				!capable(CAP_SYS_RESOURCE))
1592 			retval = -EPERM;
1593 		if (!retval)
1594 			retval = security_task_setrlimit(tsk, resource, new_rlim);
1595 	}
1596 	if (!retval) {
1597 		if (old_rlim)
1598 			*old_rlim = *rlim;
1599 		if (new_rlim)
1600 			*rlim = *new_rlim;
1601 	}
1602 	task_unlock(tsk->group_leader);
1603 
1604 	/*
1605 	 * RLIMIT_CPU handling. Arm the posix CPU timer if the limit is not
1606 	 * infinite. In case of RLIM_INFINITY the posix CPU timer code
1607 	 * ignores the rlimit.
1608 	 */
1609 	 if (!retval && new_rlim && resource == RLIMIT_CPU &&
1610 	     new_rlim->rlim_cur != RLIM_INFINITY &&
1611 	     IS_ENABLED(CONFIG_POSIX_TIMERS))
1612 		update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1613 out:
1614 	read_unlock(&tasklist_lock);
1615 	return retval;
1616 }
1617 
1618 /* rcu lock must be held */
1619 static int check_prlimit_permission(struct task_struct *task,
1620 				    unsigned int flags)
1621 {
1622 	const struct cred *cred = current_cred(), *tcred;
1623 	bool id_match;
1624 
1625 	if (current == task)
1626 		return 0;
1627 
1628 	tcred = __task_cred(task);
1629 	id_match = (uid_eq(cred->uid, tcred->euid) &&
1630 		    uid_eq(cred->uid, tcred->suid) &&
1631 		    uid_eq(cred->uid, tcred->uid)  &&
1632 		    gid_eq(cred->gid, tcred->egid) &&
1633 		    gid_eq(cred->gid, tcred->sgid) &&
1634 		    gid_eq(cred->gid, tcred->gid));
1635 	if (!id_match && !ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1636 		return -EPERM;
1637 
1638 	return security_task_prlimit(cred, tcred, flags);
1639 }
1640 
1641 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1642 		const struct rlimit64 __user *, new_rlim,
1643 		struct rlimit64 __user *, old_rlim)
1644 {
1645 	struct rlimit64 old64, new64;
1646 	struct rlimit old, new;
1647 	struct task_struct *tsk;
1648 	unsigned int checkflags = 0;
1649 	int ret;
1650 
1651 	if (old_rlim)
1652 		checkflags |= LSM_PRLIMIT_READ;
1653 
1654 	if (new_rlim) {
1655 		if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1656 			return -EFAULT;
1657 		rlim64_to_rlim(&new64, &new);
1658 		checkflags |= LSM_PRLIMIT_WRITE;
1659 	}
1660 
1661 	rcu_read_lock();
1662 	tsk = pid ? find_task_by_vpid(pid) : current;
1663 	if (!tsk) {
1664 		rcu_read_unlock();
1665 		return -ESRCH;
1666 	}
1667 	ret = check_prlimit_permission(tsk, checkflags);
1668 	if (ret) {
1669 		rcu_read_unlock();
1670 		return ret;
1671 	}
1672 	get_task_struct(tsk);
1673 	rcu_read_unlock();
1674 
1675 	ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1676 			old_rlim ? &old : NULL);
1677 
1678 	if (!ret && old_rlim) {
1679 		rlim_to_rlim64(&old, &old64);
1680 		if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1681 			ret = -EFAULT;
1682 	}
1683 
1684 	put_task_struct(tsk);
1685 	return ret;
1686 }
1687 
1688 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1689 {
1690 	struct rlimit new_rlim;
1691 
1692 	if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1693 		return -EFAULT;
1694 	return do_prlimit(current, resource, &new_rlim, NULL);
1695 }
1696 
1697 /*
1698  * It would make sense to put struct rusage in the task_struct,
1699  * except that would make the task_struct be *really big*.  After
1700  * task_struct gets moved into malloc'ed memory, it would
1701  * make sense to do this.  It will make moving the rest of the information
1702  * a lot simpler!  (Which we're not doing right now because we're not
1703  * measuring them yet).
1704  *
1705  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1706  * races with threads incrementing their own counters.  But since word
1707  * reads are atomic, we either get new values or old values and we don't
1708  * care which for the sums.  We always take the siglock to protect reading
1709  * the c* fields from p->signal from races with exit.c updating those
1710  * fields when reaping, so a sample either gets all the additions of a
1711  * given child after it's reaped, or none so this sample is before reaping.
1712  *
1713  * Locking:
1714  * We need to take the siglock for CHILDEREN, SELF and BOTH
1715  * for  the cases current multithreaded, non-current single threaded
1716  * non-current multithreaded.  Thread traversal is now safe with
1717  * the siglock held.
1718  * Strictly speaking, we donot need to take the siglock if we are current and
1719  * single threaded,  as no one else can take our signal_struct away, no one
1720  * else can  reap the  children to update signal->c* counters, and no one else
1721  * can race with the signal-> fields. If we do not take any lock, the
1722  * signal-> fields could be read out of order while another thread was just
1723  * exiting. So we should  place a read memory barrier when we avoid the lock.
1724  * On the writer side,  write memory barrier is implied in  __exit_signal
1725  * as __exit_signal releases  the siglock spinlock after updating the signal->
1726  * fields. But we don't do this yet to keep things simple.
1727  *
1728  */
1729 
1730 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1731 {
1732 	r->ru_nvcsw += t->nvcsw;
1733 	r->ru_nivcsw += t->nivcsw;
1734 	r->ru_minflt += t->min_flt;
1735 	r->ru_majflt += t->maj_flt;
1736 	r->ru_inblock += task_io_get_inblock(t);
1737 	r->ru_oublock += task_io_get_oublock(t);
1738 }
1739 
1740 void getrusage(struct task_struct *p, int who, struct rusage *r)
1741 {
1742 	struct task_struct *t;
1743 	unsigned long flags;
1744 	u64 tgutime, tgstime, utime, stime;
1745 	unsigned long maxrss = 0;
1746 
1747 	memset((char *)r, 0, sizeof (*r));
1748 	utime = stime = 0;
1749 
1750 	if (who == RUSAGE_THREAD) {
1751 		task_cputime_adjusted(current, &utime, &stime);
1752 		accumulate_thread_rusage(p, r);
1753 		maxrss = p->signal->maxrss;
1754 		goto out;
1755 	}
1756 
1757 	if (!lock_task_sighand(p, &flags))
1758 		return;
1759 
1760 	switch (who) {
1761 	case RUSAGE_BOTH:
1762 	case RUSAGE_CHILDREN:
1763 		utime = p->signal->cutime;
1764 		stime = p->signal->cstime;
1765 		r->ru_nvcsw = p->signal->cnvcsw;
1766 		r->ru_nivcsw = p->signal->cnivcsw;
1767 		r->ru_minflt = p->signal->cmin_flt;
1768 		r->ru_majflt = p->signal->cmaj_flt;
1769 		r->ru_inblock = p->signal->cinblock;
1770 		r->ru_oublock = p->signal->coublock;
1771 		maxrss = p->signal->cmaxrss;
1772 
1773 		if (who == RUSAGE_CHILDREN)
1774 			break;
1775 		fallthrough;
1776 
1777 	case RUSAGE_SELF:
1778 		thread_group_cputime_adjusted(p, &tgutime, &tgstime);
1779 		utime += tgutime;
1780 		stime += tgstime;
1781 		r->ru_nvcsw += p->signal->nvcsw;
1782 		r->ru_nivcsw += p->signal->nivcsw;
1783 		r->ru_minflt += p->signal->min_flt;
1784 		r->ru_majflt += p->signal->maj_flt;
1785 		r->ru_inblock += p->signal->inblock;
1786 		r->ru_oublock += p->signal->oublock;
1787 		if (maxrss < p->signal->maxrss)
1788 			maxrss = p->signal->maxrss;
1789 		t = p;
1790 		do {
1791 			accumulate_thread_rusage(t, r);
1792 		} while_each_thread(p, t);
1793 		break;
1794 
1795 	default:
1796 		BUG();
1797 	}
1798 	unlock_task_sighand(p, &flags);
1799 
1800 out:
1801 	r->ru_utime = ns_to_kernel_old_timeval(utime);
1802 	r->ru_stime = ns_to_kernel_old_timeval(stime);
1803 
1804 	if (who != RUSAGE_CHILDREN) {
1805 		struct mm_struct *mm = get_task_mm(p);
1806 
1807 		if (mm) {
1808 			setmax_mm_hiwater_rss(&maxrss, mm);
1809 			mmput(mm);
1810 		}
1811 	}
1812 	r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1813 }
1814 
1815 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1816 {
1817 	struct rusage r;
1818 
1819 	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1820 	    who != RUSAGE_THREAD)
1821 		return -EINVAL;
1822 
1823 	getrusage(current, who, &r);
1824 	return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1825 }
1826 
1827 #ifdef CONFIG_COMPAT
1828 COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru)
1829 {
1830 	struct rusage r;
1831 
1832 	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1833 	    who != RUSAGE_THREAD)
1834 		return -EINVAL;
1835 
1836 	getrusage(current, who, &r);
1837 	return put_compat_rusage(&r, ru);
1838 }
1839 #endif
1840 
1841 SYSCALL_DEFINE1(umask, int, mask)
1842 {
1843 	mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1844 	return mask;
1845 }
1846 
1847 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1848 {
1849 	struct fd exe;
1850 	struct inode *inode;
1851 	int err;
1852 
1853 	exe = fdget(fd);
1854 	if (!exe.file)
1855 		return -EBADF;
1856 
1857 	inode = file_inode(exe.file);
1858 
1859 	/*
1860 	 * Because the original mm->exe_file points to executable file, make
1861 	 * sure that this one is executable as well, to avoid breaking an
1862 	 * overall picture.
1863 	 */
1864 	err = -EACCES;
1865 	if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path))
1866 		goto exit;
1867 
1868 	err = file_permission(exe.file, MAY_EXEC);
1869 	if (err)
1870 		goto exit;
1871 
1872 	err = replace_mm_exe_file(mm, exe.file);
1873 exit:
1874 	fdput(exe);
1875 	return err;
1876 }
1877 
1878 /*
1879  * Check arithmetic relations of passed addresses.
1880  *
1881  * WARNING: we don't require any capability here so be very careful
1882  * in what is allowed for modification from userspace.
1883  */
1884 static int validate_prctl_map_addr(struct prctl_mm_map *prctl_map)
1885 {
1886 	unsigned long mmap_max_addr = TASK_SIZE;
1887 	int error = -EINVAL, i;
1888 
1889 	static const unsigned char offsets[] = {
1890 		offsetof(struct prctl_mm_map, start_code),
1891 		offsetof(struct prctl_mm_map, end_code),
1892 		offsetof(struct prctl_mm_map, start_data),
1893 		offsetof(struct prctl_mm_map, end_data),
1894 		offsetof(struct prctl_mm_map, start_brk),
1895 		offsetof(struct prctl_mm_map, brk),
1896 		offsetof(struct prctl_mm_map, start_stack),
1897 		offsetof(struct prctl_mm_map, arg_start),
1898 		offsetof(struct prctl_mm_map, arg_end),
1899 		offsetof(struct prctl_mm_map, env_start),
1900 		offsetof(struct prctl_mm_map, env_end),
1901 	};
1902 
1903 	/*
1904 	 * Make sure the members are not somewhere outside
1905 	 * of allowed address space.
1906 	 */
1907 	for (i = 0; i < ARRAY_SIZE(offsets); i++) {
1908 		u64 val = *(u64 *)((char *)prctl_map + offsets[i]);
1909 
1910 		if ((unsigned long)val >= mmap_max_addr ||
1911 		    (unsigned long)val < mmap_min_addr)
1912 			goto out;
1913 	}
1914 
1915 	/*
1916 	 * Make sure the pairs are ordered.
1917 	 */
1918 #define __prctl_check_order(__m1, __op, __m2)				\
1919 	((unsigned long)prctl_map->__m1 __op				\
1920 	 (unsigned long)prctl_map->__m2) ? 0 : -EINVAL
1921 	error  = __prctl_check_order(start_code, <, end_code);
1922 	error |= __prctl_check_order(start_data,<=, end_data);
1923 	error |= __prctl_check_order(start_brk, <=, brk);
1924 	error |= __prctl_check_order(arg_start, <=, arg_end);
1925 	error |= __prctl_check_order(env_start, <=, env_end);
1926 	if (error)
1927 		goto out;
1928 #undef __prctl_check_order
1929 
1930 	error = -EINVAL;
1931 
1932 	/*
1933 	 * Neither we should allow to override limits if they set.
1934 	 */
1935 	if (check_data_rlimit(rlimit(RLIMIT_DATA), prctl_map->brk,
1936 			      prctl_map->start_brk, prctl_map->end_data,
1937 			      prctl_map->start_data))
1938 			goto out;
1939 
1940 	error = 0;
1941 out:
1942 	return error;
1943 }
1944 
1945 #ifdef CONFIG_CHECKPOINT_RESTORE
1946 static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size)
1947 {
1948 	struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, };
1949 	unsigned long user_auxv[AT_VECTOR_SIZE];
1950 	struct mm_struct *mm = current->mm;
1951 	int error;
1952 
1953 	BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1954 	BUILD_BUG_ON(sizeof(struct prctl_mm_map) > 256);
1955 
1956 	if (opt == PR_SET_MM_MAP_SIZE)
1957 		return put_user((unsigned int)sizeof(prctl_map),
1958 				(unsigned int __user *)addr);
1959 
1960 	if (data_size != sizeof(prctl_map))
1961 		return -EINVAL;
1962 
1963 	if (copy_from_user(&prctl_map, addr, sizeof(prctl_map)))
1964 		return -EFAULT;
1965 
1966 	error = validate_prctl_map_addr(&prctl_map);
1967 	if (error)
1968 		return error;
1969 
1970 	if (prctl_map.auxv_size) {
1971 		/*
1972 		 * Someone is trying to cheat the auxv vector.
1973 		 */
1974 		if (!prctl_map.auxv ||
1975 				prctl_map.auxv_size > sizeof(mm->saved_auxv))
1976 			return -EINVAL;
1977 
1978 		memset(user_auxv, 0, sizeof(user_auxv));
1979 		if (copy_from_user(user_auxv,
1980 				   (const void __user *)prctl_map.auxv,
1981 				   prctl_map.auxv_size))
1982 			return -EFAULT;
1983 
1984 		/* Last entry must be AT_NULL as specification requires */
1985 		user_auxv[AT_VECTOR_SIZE - 2] = AT_NULL;
1986 		user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL;
1987 	}
1988 
1989 	if (prctl_map.exe_fd != (u32)-1) {
1990 		/*
1991 		 * Check if the current user is checkpoint/restore capable.
1992 		 * At the time of this writing, it checks for CAP_SYS_ADMIN
1993 		 * or CAP_CHECKPOINT_RESTORE.
1994 		 * Note that a user with access to ptrace can masquerade an
1995 		 * arbitrary program as any executable, even setuid ones.
1996 		 * This may have implications in the tomoyo subsystem.
1997 		 */
1998 		if (!checkpoint_restore_ns_capable(current_user_ns()))
1999 			return -EPERM;
2000 
2001 		error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd);
2002 		if (error)
2003 			return error;
2004 	}
2005 
2006 	/*
2007 	 * arg_lock protects concurrent updates but we still need mmap_lock for
2008 	 * read to exclude races with sys_brk.
2009 	 */
2010 	mmap_read_lock(mm);
2011 
2012 	/*
2013 	 * We don't validate if these members are pointing to
2014 	 * real present VMAs because application may have correspond
2015 	 * VMAs already unmapped and kernel uses these members for statistics
2016 	 * output in procfs mostly, except
2017 	 *
2018 	 *  - @start_brk/@brk which are used in do_brk_flags but kernel lookups
2019 	 *    for VMAs when updating these members so anything wrong written
2020 	 *    here cause kernel to swear at userspace program but won't lead
2021 	 *    to any problem in kernel itself
2022 	 */
2023 
2024 	spin_lock(&mm->arg_lock);
2025 	mm->start_code	= prctl_map.start_code;
2026 	mm->end_code	= prctl_map.end_code;
2027 	mm->start_data	= prctl_map.start_data;
2028 	mm->end_data	= prctl_map.end_data;
2029 	mm->start_brk	= prctl_map.start_brk;
2030 	mm->brk		= prctl_map.brk;
2031 	mm->start_stack	= prctl_map.start_stack;
2032 	mm->arg_start	= prctl_map.arg_start;
2033 	mm->arg_end	= prctl_map.arg_end;
2034 	mm->env_start	= prctl_map.env_start;
2035 	mm->env_end	= prctl_map.env_end;
2036 	spin_unlock(&mm->arg_lock);
2037 
2038 	/*
2039 	 * Note this update of @saved_auxv is lockless thus
2040 	 * if someone reads this member in procfs while we're
2041 	 * updating -- it may get partly updated results. It's
2042 	 * known and acceptable trade off: we leave it as is to
2043 	 * not introduce additional locks here making the kernel
2044 	 * more complex.
2045 	 */
2046 	if (prctl_map.auxv_size)
2047 		memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv));
2048 
2049 	mmap_read_unlock(mm);
2050 	return 0;
2051 }
2052 #endif /* CONFIG_CHECKPOINT_RESTORE */
2053 
2054 static int prctl_set_auxv(struct mm_struct *mm, unsigned long addr,
2055 			  unsigned long len)
2056 {
2057 	/*
2058 	 * This doesn't move the auxiliary vector itself since it's pinned to
2059 	 * mm_struct, but it permits filling the vector with new values.  It's
2060 	 * up to the caller to provide sane values here, otherwise userspace
2061 	 * tools which use this vector might be unhappy.
2062 	 */
2063 	unsigned long user_auxv[AT_VECTOR_SIZE] = {};
2064 
2065 	if (len > sizeof(user_auxv))
2066 		return -EINVAL;
2067 
2068 	if (copy_from_user(user_auxv, (const void __user *)addr, len))
2069 		return -EFAULT;
2070 
2071 	/* Make sure the last entry is always AT_NULL */
2072 	user_auxv[AT_VECTOR_SIZE - 2] = 0;
2073 	user_auxv[AT_VECTOR_SIZE - 1] = 0;
2074 
2075 	BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
2076 
2077 	task_lock(current);
2078 	memcpy(mm->saved_auxv, user_auxv, len);
2079 	task_unlock(current);
2080 
2081 	return 0;
2082 }
2083 
2084 static int prctl_set_mm(int opt, unsigned long addr,
2085 			unsigned long arg4, unsigned long arg5)
2086 {
2087 	struct mm_struct *mm = current->mm;
2088 	struct prctl_mm_map prctl_map = {
2089 		.auxv = NULL,
2090 		.auxv_size = 0,
2091 		.exe_fd = -1,
2092 	};
2093 	struct vm_area_struct *vma;
2094 	int error;
2095 
2096 	if (arg5 || (arg4 && (opt != PR_SET_MM_AUXV &&
2097 			      opt != PR_SET_MM_MAP &&
2098 			      opt != PR_SET_MM_MAP_SIZE)))
2099 		return -EINVAL;
2100 
2101 #ifdef CONFIG_CHECKPOINT_RESTORE
2102 	if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE)
2103 		return prctl_set_mm_map(opt, (const void __user *)addr, arg4);
2104 #endif
2105 
2106 	if (!capable(CAP_SYS_RESOURCE))
2107 		return -EPERM;
2108 
2109 	if (opt == PR_SET_MM_EXE_FILE)
2110 		return prctl_set_mm_exe_file(mm, (unsigned int)addr);
2111 
2112 	if (opt == PR_SET_MM_AUXV)
2113 		return prctl_set_auxv(mm, addr, arg4);
2114 
2115 	if (addr >= TASK_SIZE || addr < mmap_min_addr)
2116 		return -EINVAL;
2117 
2118 	error = -EINVAL;
2119 
2120 	/*
2121 	 * arg_lock protects concurrent updates of arg boundaries, we need
2122 	 * mmap_lock for a) concurrent sys_brk, b) finding VMA for addr
2123 	 * validation.
2124 	 */
2125 	mmap_read_lock(mm);
2126 	vma = find_vma(mm, addr);
2127 
2128 	spin_lock(&mm->arg_lock);
2129 	prctl_map.start_code	= mm->start_code;
2130 	prctl_map.end_code	= mm->end_code;
2131 	prctl_map.start_data	= mm->start_data;
2132 	prctl_map.end_data	= mm->end_data;
2133 	prctl_map.start_brk	= mm->start_brk;
2134 	prctl_map.brk		= mm->brk;
2135 	prctl_map.start_stack	= mm->start_stack;
2136 	prctl_map.arg_start	= mm->arg_start;
2137 	prctl_map.arg_end	= mm->arg_end;
2138 	prctl_map.env_start	= mm->env_start;
2139 	prctl_map.env_end	= mm->env_end;
2140 
2141 	switch (opt) {
2142 	case PR_SET_MM_START_CODE:
2143 		prctl_map.start_code = addr;
2144 		break;
2145 	case PR_SET_MM_END_CODE:
2146 		prctl_map.end_code = addr;
2147 		break;
2148 	case PR_SET_MM_START_DATA:
2149 		prctl_map.start_data = addr;
2150 		break;
2151 	case PR_SET_MM_END_DATA:
2152 		prctl_map.end_data = addr;
2153 		break;
2154 	case PR_SET_MM_START_STACK:
2155 		prctl_map.start_stack = addr;
2156 		break;
2157 	case PR_SET_MM_START_BRK:
2158 		prctl_map.start_brk = addr;
2159 		break;
2160 	case PR_SET_MM_BRK:
2161 		prctl_map.brk = addr;
2162 		break;
2163 	case PR_SET_MM_ARG_START:
2164 		prctl_map.arg_start = addr;
2165 		break;
2166 	case PR_SET_MM_ARG_END:
2167 		prctl_map.arg_end = addr;
2168 		break;
2169 	case PR_SET_MM_ENV_START:
2170 		prctl_map.env_start = addr;
2171 		break;
2172 	case PR_SET_MM_ENV_END:
2173 		prctl_map.env_end = addr;
2174 		break;
2175 	default:
2176 		goto out;
2177 	}
2178 
2179 	error = validate_prctl_map_addr(&prctl_map);
2180 	if (error)
2181 		goto out;
2182 
2183 	switch (opt) {
2184 	/*
2185 	 * If command line arguments and environment
2186 	 * are placed somewhere else on stack, we can
2187 	 * set them up here, ARG_START/END to setup
2188 	 * command line arguments and ENV_START/END
2189 	 * for environment.
2190 	 */
2191 	case PR_SET_MM_START_STACK:
2192 	case PR_SET_MM_ARG_START:
2193 	case PR_SET_MM_ARG_END:
2194 	case PR_SET_MM_ENV_START:
2195 	case PR_SET_MM_ENV_END:
2196 		if (!vma) {
2197 			error = -EFAULT;
2198 			goto out;
2199 		}
2200 	}
2201 
2202 	mm->start_code	= prctl_map.start_code;
2203 	mm->end_code	= prctl_map.end_code;
2204 	mm->start_data	= prctl_map.start_data;
2205 	mm->end_data	= prctl_map.end_data;
2206 	mm->start_brk	= prctl_map.start_brk;
2207 	mm->brk		= prctl_map.brk;
2208 	mm->start_stack	= prctl_map.start_stack;
2209 	mm->arg_start	= prctl_map.arg_start;
2210 	mm->arg_end	= prctl_map.arg_end;
2211 	mm->env_start	= prctl_map.env_start;
2212 	mm->env_end	= prctl_map.env_end;
2213 
2214 	error = 0;
2215 out:
2216 	spin_unlock(&mm->arg_lock);
2217 	mmap_read_unlock(mm);
2218 	return error;
2219 }
2220 
2221 #ifdef CONFIG_CHECKPOINT_RESTORE
2222 static int prctl_get_tid_address(struct task_struct *me, int __user * __user *tid_addr)
2223 {
2224 	return put_user(me->clear_child_tid, tid_addr);
2225 }
2226 #else
2227 static int prctl_get_tid_address(struct task_struct *me, int __user * __user *tid_addr)
2228 {
2229 	return -EINVAL;
2230 }
2231 #endif
2232 
2233 static int propagate_has_child_subreaper(struct task_struct *p, void *data)
2234 {
2235 	/*
2236 	 * If task has has_child_subreaper - all its descendants
2237 	 * already have these flag too and new descendants will
2238 	 * inherit it on fork, skip them.
2239 	 *
2240 	 * If we've found child_reaper - skip descendants in
2241 	 * it's subtree as they will never get out pidns.
2242 	 */
2243 	if (p->signal->has_child_subreaper ||
2244 	    is_child_reaper(task_pid(p)))
2245 		return 0;
2246 
2247 	p->signal->has_child_subreaper = 1;
2248 	return 1;
2249 }
2250 
2251 int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which)
2252 {
2253 	return -EINVAL;
2254 }
2255 
2256 int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
2257 				    unsigned long ctrl)
2258 {
2259 	return -EINVAL;
2260 }
2261 
2262 #define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE)
2263 
2264 #ifdef CONFIG_ANON_VMA_NAME
2265 
2266 #define ANON_VMA_NAME_MAX_LEN		80
2267 #define ANON_VMA_NAME_INVALID_CHARS	"\\`$[]"
2268 
2269 static inline bool is_valid_name_char(char ch)
2270 {
2271 	/* printable ascii characters, excluding ANON_VMA_NAME_INVALID_CHARS */
2272 	return ch > 0x1f && ch < 0x7f &&
2273 		!strchr(ANON_VMA_NAME_INVALID_CHARS, ch);
2274 }
2275 
2276 static int prctl_set_vma(unsigned long opt, unsigned long addr,
2277 			 unsigned long size, unsigned long arg)
2278 {
2279 	struct mm_struct *mm = current->mm;
2280 	const char __user *uname;
2281 	char *name, *pch;
2282 	int error;
2283 
2284 	switch (opt) {
2285 	case PR_SET_VMA_ANON_NAME:
2286 		uname = (const char __user *)arg;
2287 		if (uname) {
2288 			name = strndup_user(uname, ANON_VMA_NAME_MAX_LEN);
2289 
2290 			if (IS_ERR(name))
2291 				return PTR_ERR(name);
2292 
2293 			for (pch = name; *pch != '\0'; pch++) {
2294 				if (!is_valid_name_char(*pch)) {
2295 					kfree(name);
2296 					return -EINVAL;
2297 				}
2298 			}
2299 		} else {
2300 			/* Reset the name */
2301 			name = NULL;
2302 		}
2303 
2304 		mmap_write_lock(mm);
2305 		error = madvise_set_anon_name(mm, addr, size, name);
2306 		mmap_write_unlock(mm);
2307 		kfree(name);
2308 		break;
2309 	default:
2310 		error = -EINVAL;
2311 	}
2312 
2313 	return error;
2314 }
2315 
2316 #else /* CONFIG_ANON_VMA_NAME */
2317 static int prctl_set_vma(unsigned long opt, unsigned long start,
2318 			 unsigned long size, unsigned long arg)
2319 {
2320 	return -EINVAL;
2321 }
2322 #endif /* CONFIG_ANON_VMA_NAME */
2323 
2324 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2325 		unsigned long, arg4, unsigned long, arg5)
2326 {
2327 	struct task_struct *me = current;
2328 	unsigned char comm[sizeof(me->comm)];
2329 	long error;
2330 
2331 	error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2332 	if (error != -ENOSYS)
2333 		return error;
2334 
2335 	error = 0;
2336 	switch (option) {
2337 	case PR_SET_PDEATHSIG:
2338 		if (!valid_signal(arg2)) {
2339 			error = -EINVAL;
2340 			break;
2341 		}
2342 		me->pdeath_signal = arg2;
2343 		break;
2344 	case PR_GET_PDEATHSIG:
2345 		error = put_user(me->pdeath_signal, (int __user *)arg2);
2346 		break;
2347 	case PR_GET_DUMPABLE:
2348 		error = get_dumpable(me->mm);
2349 		break;
2350 	case PR_SET_DUMPABLE:
2351 		if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
2352 			error = -EINVAL;
2353 			break;
2354 		}
2355 		set_dumpable(me->mm, arg2);
2356 		break;
2357 
2358 	case PR_SET_UNALIGN:
2359 		error = SET_UNALIGN_CTL(me, arg2);
2360 		break;
2361 	case PR_GET_UNALIGN:
2362 		error = GET_UNALIGN_CTL(me, arg2);
2363 		break;
2364 	case PR_SET_FPEMU:
2365 		error = SET_FPEMU_CTL(me, arg2);
2366 		break;
2367 	case PR_GET_FPEMU:
2368 		error = GET_FPEMU_CTL(me, arg2);
2369 		break;
2370 	case PR_SET_FPEXC:
2371 		error = SET_FPEXC_CTL(me, arg2);
2372 		break;
2373 	case PR_GET_FPEXC:
2374 		error = GET_FPEXC_CTL(me, arg2);
2375 		break;
2376 	case PR_GET_TIMING:
2377 		error = PR_TIMING_STATISTICAL;
2378 		break;
2379 	case PR_SET_TIMING:
2380 		if (arg2 != PR_TIMING_STATISTICAL)
2381 			error = -EINVAL;
2382 		break;
2383 	case PR_SET_NAME:
2384 		comm[sizeof(me->comm) - 1] = 0;
2385 		if (strncpy_from_user(comm, (char __user *)arg2,
2386 				      sizeof(me->comm) - 1) < 0)
2387 			return -EFAULT;
2388 		set_task_comm(me, comm);
2389 		proc_comm_connector(me);
2390 		break;
2391 	case PR_GET_NAME:
2392 		get_task_comm(comm, me);
2393 		if (copy_to_user((char __user *)arg2, comm, sizeof(comm)))
2394 			return -EFAULT;
2395 		break;
2396 	case PR_GET_ENDIAN:
2397 		error = GET_ENDIAN(me, arg2);
2398 		break;
2399 	case PR_SET_ENDIAN:
2400 		error = SET_ENDIAN(me, arg2);
2401 		break;
2402 	case PR_GET_SECCOMP:
2403 		error = prctl_get_seccomp();
2404 		break;
2405 	case PR_SET_SECCOMP:
2406 		error = prctl_set_seccomp(arg2, (char __user *)arg3);
2407 		break;
2408 	case PR_GET_TSC:
2409 		error = GET_TSC_CTL(arg2);
2410 		break;
2411 	case PR_SET_TSC:
2412 		error = SET_TSC_CTL(arg2);
2413 		break;
2414 	case PR_TASK_PERF_EVENTS_DISABLE:
2415 		error = perf_event_task_disable();
2416 		break;
2417 	case PR_TASK_PERF_EVENTS_ENABLE:
2418 		error = perf_event_task_enable();
2419 		break;
2420 	case PR_GET_TIMERSLACK:
2421 		if (current->timer_slack_ns > ULONG_MAX)
2422 			error = ULONG_MAX;
2423 		else
2424 			error = current->timer_slack_ns;
2425 		break;
2426 	case PR_SET_TIMERSLACK:
2427 		if (arg2 <= 0)
2428 			current->timer_slack_ns =
2429 					current->default_timer_slack_ns;
2430 		else
2431 			current->timer_slack_ns = arg2;
2432 		break;
2433 	case PR_MCE_KILL:
2434 		if (arg4 | arg5)
2435 			return -EINVAL;
2436 		switch (arg2) {
2437 		case PR_MCE_KILL_CLEAR:
2438 			if (arg3 != 0)
2439 				return -EINVAL;
2440 			current->flags &= ~PF_MCE_PROCESS;
2441 			break;
2442 		case PR_MCE_KILL_SET:
2443 			current->flags |= PF_MCE_PROCESS;
2444 			if (arg3 == PR_MCE_KILL_EARLY)
2445 				current->flags |= PF_MCE_EARLY;
2446 			else if (arg3 == PR_MCE_KILL_LATE)
2447 				current->flags &= ~PF_MCE_EARLY;
2448 			else if (arg3 == PR_MCE_KILL_DEFAULT)
2449 				current->flags &=
2450 						~(PF_MCE_EARLY|PF_MCE_PROCESS);
2451 			else
2452 				return -EINVAL;
2453 			break;
2454 		default:
2455 			return -EINVAL;
2456 		}
2457 		break;
2458 	case PR_MCE_KILL_GET:
2459 		if (arg2 | arg3 | arg4 | arg5)
2460 			return -EINVAL;
2461 		if (current->flags & PF_MCE_PROCESS)
2462 			error = (current->flags & PF_MCE_EARLY) ?
2463 				PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2464 		else
2465 			error = PR_MCE_KILL_DEFAULT;
2466 		break;
2467 	case PR_SET_MM:
2468 		error = prctl_set_mm(arg2, arg3, arg4, arg5);
2469 		break;
2470 	case PR_GET_TID_ADDRESS:
2471 		error = prctl_get_tid_address(me, (int __user * __user *)arg2);
2472 		break;
2473 	case PR_SET_CHILD_SUBREAPER:
2474 		me->signal->is_child_subreaper = !!arg2;
2475 		if (!arg2)
2476 			break;
2477 
2478 		walk_process_tree(me, propagate_has_child_subreaper, NULL);
2479 		break;
2480 	case PR_GET_CHILD_SUBREAPER:
2481 		error = put_user(me->signal->is_child_subreaper,
2482 				 (int __user *)arg2);
2483 		break;
2484 	case PR_SET_NO_NEW_PRIVS:
2485 		if (arg2 != 1 || arg3 || arg4 || arg5)
2486 			return -EINVAL;
2487 
2488 		task_set_no_new_privs(current);
2489 		break;
2490 	case PR_GET_NO_NEW_PRIVS:
2491 		if (arg2 || arg3 || arg4 || arg5)
2492 			return -EINVAL;
2493 		return task_no_new_privs(current) ? 1 : 0;
2494 	case PR_GET_THP_DISABLE:
2495 		if (arg2 || arg3 || arg4 || arg5)
2496 			return -EINVAL;
2497 		error = !!test_bit(MMF_DISABLE_THP, &me->mm->flags);
2498 		break;
2499 	case PR_SET_THP_DISABLE:
2500 		if (arg3 || arg4 || arg5)
2501 			return -EINVAL;
2502 		if (mmap_write_lock_killable(me->mm))
2503 			return -EINTR;
2504 		if (arg2)
2505 			set_bit(MMF_DISABLE_THP, &me->mm->flags);
2506 		else
2507 			clear_bit(MMF_DISABLE_THP, &me->mm->flags);
2508 		mmap_write_unlock(me->mm);
2509 		break;
2510 	case PR_MPX_ENABLE_MANAGEMENT:
2511 	case PR_MPX_DISABLE_MANAGEMENT:
2512 		/* No longer implemented: */
2513 		return -EINVAL;
2514 	case PR_SET_FP_MODE:
2515 		error = SET_FP_MODE(me, arg2);
2516 		break;
2517 	case PR_GET_FP_MODE:
2518 		error = GET_FP_MODE(me);
2519 		break;
2520 	case PR_SVE_SET_VL:
2521 		error = SVE_SET_VL(arg2);
2522 		break;
2523 	case PR_SVE_GET_VL:
2524 		error = SVE_GET_VL();
2525 		break;
2526 	case PR_GET_SPECULATION_CTRL:
2527 		if (arg3 || arg4 || arg5)
2528 			return -EINVAL;
2529 		error = arch_prctl_spec_ctrl_get(me, arg2);
2530 		break;
2531 	case PR_SET_SPECULATION_CTRL:
2532 		if (arg4 || arg5)
2533 			return -EINVAL;
2534 		error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
2535 		break;
2536 	case PR_PAC_RESET_KEYS:
2537 		if (arg3 || arg4 || arg5)
2538 			return -EINVAL;
2539 		error = PAC_RESET_KEYS(me, arg2);
2540 		break;
2541 	case PR_PAC_SET_ENABLED_KEYS:
2542 		if (arg4 || arg5)
2543 			return -EINVAL;
2544 		error = PAC_SET_ENABLED_KEYS(me, arg2, arg3);
2545 		break;
2546 	case PR_PAC_GET_ENABLED_KEYS:
2547 		if (arg2 || arg3 || arg4 || arg5)
2548 			return -EINVAL;
2549 		error = PAC_GET_ENABLED_KEYS(me);
2550 		break;
2551 	case PR_SET_TAGGED_ADDR_CTRL:
2552 		if (arg3 || arg4 || arg5)
2553 			return -EINVAL;
2554 		error = SET_TAGGED_ADDR_CTRL(arg2);
2555 		break;
2556 	case PR_GET_TAGGED_ADDR_CTRL:
2557 		if (arg2 || arg3 || arg4 || arg5)
2558 			return -EINVAL;
2559 		error = GET_TAGGED_ADDR_CTRL();
2560 		break;
2561 	case PR_SET_IO_FLUSHER:
2562 		if (!capable(CAP_SYS_RESOURCE))
2563 			return -EPERM;
2564 
2565 		if (arg3 || arg4 || arg5)
2566 			return -EINVAL;
2567 
2568 		if (arg2 == 1)
2569 			current->flags |= PR_IO_FLUSHER;
2570 		else if (!arg2)
2571 			current->flags &= ~PR_IO_FLUSHER;
2572 		else
2573 			return -EINVAL;
2574 		break;
2575 	case PR_GET_IO_FLUSHER:
2576 		if (!capable(CAP_SYS_RESOURCE))
2577 			return -EPERM;
2578 
2579 		if (arg2 || arg3 || arg4 || arg5)
2580 			return -EINVAL;
2581 
2582 		error = (current->flags & PR_IO_FLUSHER) == PR_IO_FLUSHER;
2583 		break;
2584 	case PR_SET_SYSCALL_USER_DISPATCH:
2585 		error = set_syscall_user_dispatch(arg2, arg3, arg4,
2586 						  (char __user *) arg5);
2587 		break;
2588 #ifdef CONFIG_SCHED_CORE
2589 	case PR_SCHED_CORE:
2590 		error = sched_core_share_pid(arg2, arg3, arg4, arg5);
2591 		break;
2592 #endif
2593 	case PR_SET_VMA:
2594 		error = prctl_set_vma(arg2, arg3, arg4, arg5);
2595 		break;
2596 	default:
2597 		error = -EINVAL;
2598 		break;
2599 	}
2600 	return error;
2601 }
2602 
2603 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2604 		struct getcpu_cache __user *, unused)
2605 {
2606 	int err = 0;
2607 	int cpu = raw_smp_processor_id();
2608 
2609 	if (cpup)
2610 		err |= put_user(cpu, cpup);
2611 	if (nodep)
2612 		err |= put_user(cpu_to_node(cpu), nodep);
2613 	return err ? -EFAULT : 0;
2614 }
2615 
2616 /**
2617  * do_sysinfo - fill in sysinfo struct
2618  * @info: pointer to buffer to fill
2619  */
2620 static int do_sysinfo(struct sysinfo *info)
2621 {
2622 	unsigned long mem_total, sav_total;
2623 	unsigned int mem_unit, bitcount;
2624 	struct timespec64 tp;
2625 
2626 	memset(info, 0, sizeof(struct sysinfo));
2627 
2628 	ktime_get_boottime_ts64(&tp);
2629 	timens_add_boottime(&tp);
2630 	info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
2631 
2632 	get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
2633 
2634 	info->procs = nr_threads;
2635 
2636 	si_meminfo(info);
2637 	si_swapinfo(info);
2638 
2639 	/*
2640 	 * If the sum of all the available memory (i.e. ram + swap)
2641 	 * is less than can be stored in a 32 bit unsigned long then
2642 	 * we can be binary compatible with 2.2.x kernels.  If not,
2643 	 * well, in that case 2.2.x was broken anyways...
2644 	 *
2645 	 *  -Erik Andersen <andersee@debian.org>
2646 	 */
2647 
2648 	mem_total = info->totalram + info->totalswap;
2649 	if (mem_total < info->totalram || mem_total < info->totalswap)
2650 		goto out;
2651 	bitcount = 0;
2652 	mem_unit = info->mem_unit;
2653 	while (mem_unit > 1) {
2654 		bitcount++;
2655 		mem_unit >>= 1;
2656 		sav_total = mem_total;
2657 		mem_total <<= 1;
2658 		if (mem_total < sav_total)
2659 			goto out;
2660 	}
2661 
2662 	/*
2663 	 * If mem_total did not overflow, multiply all memory values by
2664 	 * info->mem_unit and set it to 1.  This leaves things compatible
2665 	 * with 2.2.x, and also retains compatibility with earlier 2.4.x
2666 	 * kernels...
2667 	 */
2668 
2669 	info->mem_unit = 1;
2670 	info->totalram <<= bitcount;
2671 	info->freeram <<= bitcount;
2672 	info->sharedram <<= bitcount;
2673 	info->bufferram <<= bitcount;
2674 	info->totalswap <<= bitcount;
2675 	info->freeswap <<= bitcount;
2676 	info->totalhigh <<= bitcount;
2677 	info->freehigh <<= bitcount;
2678 
2679 out:
2680 	return 0;
2681 }
2682 
2683 SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
2684 {
2685 	struct sysinfo val;
2686 
2687 	do_sysinfo(&val);
2688 
2689 	if (copy_to_user(info, &val, sizeof(struct sysinfo)))
2690 		return -EFAULT;
2691 
2692 	return 0;
2693 }
2694 
2695 #ifdef CONFIG_COMPAT
2696 struct compat_sysinfo {
2697 	s32 uptime;
2698 	u32 loads[3];
2699 	u32 totalram;
2700 	u32 freeram;
2701 	u32 sharedram;
2702 	u32 bufferram;
2703 	u32 totalswap;
2704 	u32 freeswap;
2705 	u16 procs;
2706 	u16 pad;
2707 	u32 totalhigh;
2708 	u32 freehigh;
2709 	u32 mem_unit;
2710 	char _f[20-2*sizeof(u32)-sizeof(int)];
2711 };
2712 
2713 COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info)
2714 {
2715 	struct sysinfo s;
2716 	struct compat_sysinfo s_32;
2717 
2718 	do_sysinfo(&s);
2719 
2720 	/* Check to see if any memory value is too large for 32-bit and scale
2721 	 *  down if needed
2722 	 */
2723 	if (upper_32_bits(s.totalram) || upper_32_bits(s.totalswap)) {
2724 		int bitcount = 0;
2725 
2726 		while (s.mem_unit < PAGE_SIZE) {
2727 			s.mem_unit <<= 1;
2728 			bitcount++;
2729 		}
2730 
2731 		s.totalram >>= bitcount;
2732 		s.freeram >>= bitcount;
2733 		s.sharedram >>= bitcount;
2734 		s.bufferram >>= bitcount;
2735 		s.totalswap >>= bitcount;
2736 		s.freeswap >>= bitcount;
2737 		s.totalhigh >>= bitcount;
2738 		s.freehigh >>= bitcount;
2739 	}
2740 
2741 	memset(&s_32, 0, sizeof(s_32));
2742 	s_32.uptime = s.uptime;
2743 	s_32.loads[0] = s.loads[0];
2744 	s_32.loads[1] = s.loads[1];
2745 	s_32.loads[2] = s.loads[2];
2746 	s_32.totalram = s.totalram;
2747 	s_32.freeram = s.freeram;
2748 	s_32.sharedram = s.sharedram;
2749 	s_32.bufferram = s.bufferram;
2750 	s_32.totalswap = s.totalswap;
2751 	s_32.freeswap = s.freeswap;
2752 	s_32.procs = s.procs;
2753 	s_32.totalhigh = s.totalhigh;
2754 	s_32.freehigh = s.freehigh;
2755 	s_32.mem_unit = s.mem_unit;
2756 	if (copy_to_user(info, &s_32, sizeof(s_32)))
2757 		return -EFAULT;
2758 	return 0;
2759 }
2760 #endif /* CONFIG_COMPAT */
2761