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