kernel/sys.c

   1 /*
   2  *  linux/kernel/sys.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/export.h>
   8 #include <linux/mm.h>
   9 #include <linux/utsname.h>
  10 #include <linux/mman.h>
  11 #include <linux/reboot.h>
  12 #include <linux/prctl.h>
  13 #include <linux/highuid.h>
  14 #include <linux/fs.h>
  15 #include <linux/kmod.h>
  16 #include <linux/perf_event.h>
  17 #include <linux/resource.h>
  18 #include <linux/kernel.h>
  19 #include <linux/kexec.h>
  20 #include <linux/workqueue.h>
  21 #include <linux/capability.h>
  22 #include <linux/device.h>
  23 #include <linux/key.h>
  24 #include <linux/times.h>
  25 #include <linux/posix-timers.h>
  26 #include <linux/security.h>
  27 #include <linux/dcookies.h>
  28 #include <linux/suspend.h>
  29 #include <linux/tty.h>
  30 #include <linux/signal.h>
  31 #include <linux/cn_proc.h>
  32 #include <linux/getcpu.h>
  33 #include <linux/task_io_accounting_ops.h>
  34 #include <linux/seccomp.h>
  35 #include <linux/cpu.h>
  36 #include <linux/personality.h>
  37 #include <linux/ptrace.h>
  38 #include <linux/fs_struct.h>
  39 #include <linux/file.h>
  40 #include <linux/mount.h>
  41 #include <linux/gfp.h>
  42 #include <linux/syscore_ops.h>
  43 #include <linux/version.h>
  44 #include <linux/ctype.h>
  45
  46 #include <linux/compat.h>
  47 #include <linux/syscalls.h>
  48 #include <linux/kprobes.h>
  49 #include <linux/user_namespace.h>
  50
  51 #include <linux/kmsg_dump.h>
  52 /* Move somewhere else to avoid recompiling? */
  53 #include <generated/utsrelease.h>
  54
  55 #include <asm/uaccess.h>
  56 #include <asm/io.h>
  57 #include <asm/unistd.h>
  58
  59 #ifndef SET_UNALIGN_CTL
  60 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  61 #endif
  62 #ifndef GET_UNALIGN_CTL
  63 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  64 #endif
  65 #ifndef SET_FPEMU_CTL
  66 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  67 #endif
  68 #ifndef GET_FPEMU_CTL
  69 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  70 #endif
  71 #ifndef SET_FPEXC_CTL
  72 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  73 #endif
  74 #ifndef GET_FPEXC_CTL
  75 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  76 #endif
  77 #ifndef GET_ENDIAN
  78 # define GET_ENDIAN(a,b)        (-EINVAL)
  79 #endif
  80 #ifndef SET_ENDIAN
  81 # define SET_ENDIAN(a,b)        (-EINVAL)
  82 #endif
  83 #ifndef GET_TSC_CTL
  84 # define GET_TSC_CTL(a)         (-EINVAL)
  85 #endif
  86 #ifndef SET_TSC_CTL
  87 # define SET_TSC_CTL(a)         (-EINVAL)
  88 #endif
  89
  90 /*
  91  * this is where the system-wide overflow UID and GID are defined, for
  92  * architectures that now have 32-bit UID/GID but didn't in the past
  93  */
  94
  95 int overflowuid = DEFAULT_OVERFLOWUID;
  96 int overflowgid = DEFAULT_OVERFLOWGID;
  97
  98 EXPORT_SYMBOL(overflowuid);
  99 EXPORT_SYMBOL(overflowgid);
 100
 101 /*
 102  * the same as above, but for filesystems which can only store a 16-bit
 103  * UID and GID. as such, this is needed on all architectures
 104  */
 105
 106 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
 107 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
 108
 109 EXPORT_SYMBOL(fs_overflowuid);
 110 EXPORT_SYMBOL(fs_overflowgid);
 111
 112 /*
 113  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
 114  */
 115
 116 int C_A_D = 1;
 117 struct pid *cad_pid;
 118 EXPORT_SYMBOL(cad_pid);
 119
 120 /*
 121  * If set, this is used for preparing the system to power off.
 122  */
 123
 124 void (*pm_power_off_prepare)(void);
 125
 126 /*
 127  * Returns true if current's euid is same as p's uid or euid,
 128  * or has CAP_SYS_NICE to p's user_ns.
 129  *
 130  * Called with rcu_read_lock, creds are safe
 131  */
 132 static bool set_one_prio_perm(struct task_struct *p)
 133 {
 134         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 135
 136         if (uid_eq(pcred->uid,  cred->euid) ||
 137             uid_eq(pcred->euid, cred->euid))
 138                 return true;
 139         if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
 140                 return true;
 141         return false;
 142 }
 143
 144 /*
 145  * set the priority of a task
 146  * - the caller must hold the RCU read lock
 147  */
 148 static int set_one_prio(struct task_struct *p, int niceval, int error)
 149 {
 150         int no_nice;
 151
 152         if (!set_one_prio_perm(p)) {
 153                 error = -EPERM;
 154                 goto out;
 155         }
 156         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 157                 error = -EACCES;
 158                 goto out;
 159         }
 160         no_nice = security_task_setnice(p, niceval);
 161         if (no_nice) {
 162                 error = no_nice;
 163                 goto out;
 164         }
 165         if (error == -ESRCH)
 166                 error = 0;
 167         set_user_nice(p, niceval);
 168 out:
 169         return error;
 170 }
 171
 172 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 173 {
 174         struct task_struct *g, *p;
 175         struct user_struct *user;
 176         const struct cred *cred = current_cred();
 177         int error = -EINVAL;
 178         struct pid *pgrp;
 179         kuid_t uid;
 180
 181         if (which > PRIO_USER || which < PRIO_PROCESS)
 182                 goto out;
 183
 184         /* normalize: avoid signed division (rounding problems) */
 185         error = -ESRCH;
 186         if (niceval < -20)
 187                 niceval = -20;
 188         if (niceval > 19)
 189                 niceval = 19;
 190
 191         rcu_read_lock();
 192         read_lock(&tasklist_lock);
 193         switch (which) {
 194                 case PRIO_PROCESS:
 195                         if (who)
 196                                 p = find_task_by_vpid(who);
 197                         else
 198                                 p = current;
 199                         if (p)
 200                                 error = set_one_prio(p, niceval, error);
 201                         break;
 202                 case PRIO_PGRP:
 203                         if (who)
 204                                 pgrp = find_vpid(who);
 205                         else
 206                                 pgrp = task_pgrp(current);
 207                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 208                                 error = set_one_prio(p, niceval, error);
 209                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 210                         break;
 211                 case PRIO_USER:
 212                         uid = make_kuid(cred->user_ns, who);
 213                         user = cred->user;
 214                         if (!who)
 215                                 uid = cred->uid;
 216                         else if (!uid_eq(uid, cred->uid) &&
 217                                  !(user = find_user(uid)))
 218                                 goto out_unlock;        /* No processes for this user */
 219
 220                         do_each_thread(g, p) {
 221                                 if (uid_eq(task_uid(p), uid))
 222                                         error = set_one_prio(p, niceval, error);
 223                         } while_each_thread(g, p);
 224                         if (!uid_eq(uid, cred->uid))
 225                                 free_uid(user);         /* For find_user() */
 226                         break;
 227         }
 228 out_unlock:
 229         read_unlock(&tasklist_lock);
 230         rcu_read_unlock();
 231 out:
 232         return error;
 233 }
 234
 235 /*
 236  * Ugh. To avoid negative return values, "getpriority()" will
 237  * not return the normal nice-value, but a negated value that
 238  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 239  * to stay compatible.
 240  */
 241 SYSCALL_DEFINE2(getpriority, int, which, int, who)
 242 {
 243         struct task_struct *g, *p;
 244         struct user_struct *user;
 245         const struct cred *cred = current_cred();
 246         long niceval, retval = -ESRCH;
 247         struct pid *pgrp;
 248         kuid_t uid;
 249
 250         if (which > PRIO_USER || which < PRIO_PROCESS)
 251                 return -EINVAL;
 252
 253         rcu_read_lock();
 254         read_lock(&tasklist_lock);
 255         switch (which) {
 256                 case PRIO_PROCESS:
 257                         if (who)
 258                                 p = find_task_by_vpid(who);
 259                         else
 260                                 p = current;
 261                         if (p) {
 262                                 niceval = 20 - task_nice(p);
 263                                 if (niceval > retval)
 264                                         retval = niceval;
 265                         }
 266                         break;
 267                 case PRIO_PGRP:
 268                         if (who)
 269                                 pgrp = find_vpid(who);
 270                         else
 271                                 pgrp = task_pgrp(current);
 272                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 273                                 niceval = 20 - task_nice(p);
 274                                 if (niceval > retval)
 275                                         retval = niceval;
 276                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 277                         break;
 278                 case PRIO_USER:
 279                         uid = make_kuid(cred->user_ns, who);
 280                         user = cred->user;
 281                         if (!who)
 282                                 uid = cred->uid;
 283                         else if (!uid_eq(uid, cred->uid) &&
 284                                  !(user = find_user(uid)))
 285                                 goto out_unlock;        /* No processes for this user */
 286
 287                         do_each_thread(g, p) {
 288                                 if (uid_eq(task_uid(p), uid)) {
 289                                         niceval = 20 - task_nice(p);
 290                                         if (niceval > retval)
 291                                                 retval = niceval;
 292                                 }
 293                         } while_each_thread(g, p);
 294                         if (!uid_eq(uid, cred->uid))
 295                                 free_uid(user);         /* for find_user() */
 296                         break;
 297         }
 298 out_unlock:
 299         read_unlock(&tasklist_lock);
 300         rcu_read_unlock();
 301
 302         return retval;
 303 }
 304
 305 /**
 306  *      emergency_restart - reboot the system
 307  *
 308  *      Without shutting down any hardware or taking any locks
 309  *      reboot the system.  This is called when we know we are in
 310  *      trouble so this is our best effort to reboot.  This is
 311  *      safe to call in interrupt context.
 312  */
 313 void emergency_restart(void)
 314 {
 315         kmsg_dump(KMSG_DUMP_EMERG);
 316         machine_emergency_restart();
 317 }
 318 EXPORT_SYMBOL_GPL(emergency_restart);
 319
 320 void kernel_restart_prepare(char *cmd)
 321 {
 322         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 323         system_state = SYSTEM_RESTART;
 324         usermodehelper_disable();
 325         device_shutdown();
 326         syscore_shutdown();
 327 }
 328
 329 /**
 330  *      register_reboot_notifier - Register function to be called at reboot time
 331  *      @nb: Info about notifier function to be called
 332  *
 333  *      Registers a function with the list of functions
 334  *      to be called at reboot time.
 335  *
 336  *      Currently always returns zero, as blocking_notifier_chain_register()
 337  *      always returns zero.
 338  */
 339 int register_reboot_notifier(struct notifier_block *nb)
 340 {
 341         return blocking_notifier_chain_register(&reboot_notifier_list, nb);
 342 }
 343 EXPORT_SYMBOL(register_reboot_notifier);
 344
 345 /**
 346  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
 347  *      @nb: Hook to be unregistered
 348  *
 349  *      Unregisters a previously registered reboot
 350  *      notifier function.
 351  *
 352  *      Returns zero on success, or %-ENOENT on failure.
 353  */
 354 int unregister_reboot_notifier(struct notifier_block *nb)
 355 {
 356         return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
 357 }
 358 EXPORT_SYMBOL(unregister_reboot_notifier);
 359
 360 /**
 361  *      kernel_restart - reboot the system
 362  *      @cmd: pointer to buffer containing command to execute for restart
 363  *              or %NULL
 364  *
 365  *      Shutdown everything and perform a clean reboot.
 366  *      This is not safe to call in interrupt context.
 367  */
 368 void kernel_restart(char *cmd)
 369 {
 370         kernel_restart_prepare(cmd);
 371         if (!cmd)
 372                 printk(KERN_EMERG "Restarting system.\n");
 373         else
 374                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 375         kmsg_dump(KMSG_DUMP_RESTART);
 376         machine_restart(cmd);
 377 }
 378 EXPORT_SYMBOL_GPL(kernel_restart);
 379
 380 static void kernel_shutdown_prepare(enum system_states state)
 381 {
 382         blocking_notifier_call_chain(&reboot_notifier_list,
 383                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 384         system_state = state;
 385         usermodehelper_disable();
 386         device_shutdown();
 387 }
 388 /**
 389  *      kernel_halt - halt the system
 390  *
 391  *      Shutdown everything and perform a clean system halt.
 392  */
 393 void kernel_halt(void)
 394 {
 395         kernel_shutdown_prepare(SYSTEM_HALT);
 396         syscore_shutdown();
 397         printk(KERN_EMERG "System halted.\n");
 398         kmsg_dump(KMSG_DUMP_HALT);
 399         machine_halt();
 400 }
 401
 402 EXPORT_SYMBOL_GPL(kernel_halt);
 403
 404 /**
 405  *      kernel_power_off - power_off the system
 406  *
 407  *      Shutdown everything and perform a clean system power_off.
 408  */
 409 void kernel_power_off(void)
 410 {
 411         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 412         if (pm_power_off_prepare)
 413                 pm_power_off_prepare();
 414         disable_nonboot_cpus();
 415         syscore_shutdown();
 416         printk(KERN_EMERG "Power down.\n");
 417         kmsg_dump(KMSG_DUMP_POWEROFF);
 418         machine_power_off();
 419 }
 420 EXPORT_SYMBOL_GPL(kernel_power_off);
 421
 422 static DEFINE_MUTEX(reboot_mutex);
 423
 424 /*
 425  * Reboot system call: for obvious reasons only root may call it,
 426  * and even root needs to set up some magic numbers in the registers
 427  * so that some mistake won't make this reboot the whole machine.
 428  * You can also set the meaning of the ctrl-alt-del-key here.
 429  *
 430  * reboot doesn't sync: do that yourself before calling this.
 431  */
 432 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 433                 void __user *, arg)
 434 {
 435         char buffer[256];
 436         int ret = 0;
 437
 438         /* We only trust the superuser with rebooting the system. */
 439         if (!capable(CAP_SYS_BOOT))
 440                 return -EPERM;
 441
 442         /* For safety, we require "magic" arguments. */
 443         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 444             (magic2 != LINUX_REBOOT_MAGIC2 &&
 445                         magic2 != LINUX_REBOOT_MAGIC2A &&
 446                         magic2 != LINUX_REBOOT_MAGIC2B &&
 447                         magic2 != LINUX_REBOOT_MAGIC2C))
 448                 return -EINVAL;
 449
 450         /*
 451          * If pid namespaces are enabled and the current task is in a child
 452          * pid_namespace, the command is handled by reboot_pid_ns() which will
 453          * call do_exit().
 454          */
 455         ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
 456         if (ret)
 457                 return ret;
 458
 459         /* Instead of trying to make the power_off code look like
 460          * halt when pm_power_off is not set do it the easy way.
 461          */
 462         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 463                 cmd = LINUX_REBOOT_CMD_HALT;
 464
 465         mutex_lock(&reboot_mutex);
 466         switch (cmd) {
 467         case LINUX_REBOOT_CMD_RESTART:
 468                 kernel_restart(NULL);
 469                 break;
 470
 471         case LINUX_REBOOT_CMD_CAD_ON:
 472                 C_A_D = 1;
 473                 break;
 474
 475         case LINUX_REBOOT_CMD_CAD_OFF:
 476                 C_A_D = 0;
 477                 break;
 478
 479         case LINUX_REBOOT_CMD_HALT:
 480                 kernel_halt();
 481                 do_exit(0);
 482                 panic("cannot halt");
 483
 484         case LINUX_REBOOT_CMD_POWER_OFF:
 485                 kernel_power_off();
 486                 do_exit(0);
 487                 break;
 488
 489         case LINUX_REBOOT_CMD_RESTART2:
 490                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 491                         ret = -EFAULT;
 492                         break;
 493                 }
 494                 buffer[sizeof(buffer) - 1] = '\0';
 495
 496                 kernel_restart(buffer);
 497                 break;
 498
 499 #ifdef CONFIG_KEXEC
 500         case LINUX_REBOOT_CMD_KEXEC:
 501                 ret = kernel_kexec();
 502                 break;
 503 #endif
 504
 505 #ifdef CONFIG_HIBERNATION
 506         case LINUX_REBOOT_CMD_SW_SUSPEND:
 507                 ret = hibernate();
 508                 break;
 509 #endif
 510
 511         default:
 512                 ret = -EINVAL;
 513                 break;
 514         }
 515         mutex_unlock(&reboot_mutex);
 516         return ret;
 517 }
 518
 519 static void deferred_cad(struct work_struct *dummy)
 520 {
 521         kernel_restart(NULL);
 522 }
 523
 524 /*
 525  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 526  * As it's called within an interrupt, it may NOT sync: the only choice
 527  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 528  */
 529 void ctrl_alt_del(void)
 530 {
 531         static DECLARE_WORK(cad_work, deferred_cad);
 532
 533         if (C_A_D)
 534                 schedule_work(&cad_work);
 535         else
 536                 kill_cad_pid(SIGINT, 1);
 537 }
 538
 539 /*
 540  * Unprivileged users may change the real gid to the effective gid
 541  * or vice versa.  (BSD-style)
 542  *
 543  * If you set the real gid at all, or set the effective gid to a value not
 544  * equal to the real gid, then the saved gid is set to the new effective gid.
 545  *
 546  * This makes it possible for a setgid program to completely drop its
 547  * privileges, which is often a useful assertion to make when you are doing
 548  * a security audit over a program.
 549  *
 550  * The general idea is that a program which uses just setregid() will be
 551  * 100% compatible with BSD.  A program which uses just setgid() will be
 552  * 100% compatible with POSIX with saved IDs.
 553  *
 554  * SMP: There are not races, the GIDs are checked only by filesystem
 555  *      operations (as far as semantic preservation is concerned).
 556  */
 557 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 558 {
 559         struct user_namespace *ns = current_user_ns();
 560         const struct cred *old;
 561         struct cred *new;
 562         int retval;
 563         kgid_t krgid, kegid;
 564
 565         krgid = make_kgid(ns, rgid);
 566         kegid = make_kgid(ns, egid);
 567
 568         if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 569                 return -EINVAL;
 570         if ((egid != (gid_t) -1) && !gid_valid(kegid))
 571                 return -EINVAL;
 572
 573         new = prepare_creds();
 574         if (!new)
 575                 return -ENOMEM;
 576         old = current_cred();
 577
 578         retval = -EPERM;
 579         if (rgid != (gid_t) -1) {
 580                 if (gid_eq(old->gid, krgid) ||
 581                     gid_eq(old->egid, krgid) ||
 582                     nsown_capable(CAP_SETGID))
 583                         new->gid = krgid;
 584                 else
 585                         goto error;
 586         }
 587         if (egid != (gid_t) -1) {
 588                 if (gid_eq(old->gid, kegid) ||
 589                     gid_eq(old->egid, kegid) ||
 590                     gid_eq(old->sgid, kegid) ||
 591                     nsown_capable(CAP_SETGID))
 592                         new->egid = kegid;
 593                 else
 594                         goto error;
 595         }
 596
 597         if (rgid != (gid_t) -1 ||
 598             (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
 599                 new->sgid = new->egid;
 600         new->fsgid = new->egid;
 601
 602         return commit_creds(new);
 603
 604 error:
 605         abort_creds(new);
 606         return retval;
 607 }
 608
 609 /*
 610  * setgid() is implemented like SysV w/ SAVED_IDS
 611  *
 612  * SMP: Same implicit races as above.
 613  */
 614 SYSCALL_DEFINE1(setgid, gid_t, gid)
 615 {
 616         struct user_namespace *ns = current_user_ns();
 617         const struct cred *old;
 618         struct cred *new;
 619         int retval;
 620         kgid_t kgid;
 621
 622         kgid = make_kgid(ns, gid);
 623         if (!gid_valid(kgid))
 624                 return -EINVAL;
 625
 626         new = prepare_creds();
 627         if (!new)
 628                 return -ENOMEM;
 629         old = current_cred();
 630
 631         retval = -EPERM;
 632         if (nsown_capable(CAP_SETGID))
 633                 new->gid = new->egid = new->sgid = new->fsgid = kgid;
 634         else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
 635                 new->egid = new->fsgid = kgid;
 636         else
 637                 goto error;
 638
 639         return commit_creds(new);
 640
 641 error:
 642         abort_creds(new);
 643         return retval;
 644 }
 645
 646 /*
 647  * change the user struct in a credentials set to match the new UID
 648  */
 649 static int set_user(struct cred *new)
 650 {
 651         struct user_struct *new_user;
 652
 653         new_user = alloc_uid(new->uid);
 654         if (!new_user)
 655                 return -EAGAIN;
 656
 657         /*
 658          * We don't fail in case of NPROC limit excess here because too many
 659          * poorly written programs don't check set*uid() return code, assuming
 660          * it never fails if called by root.  We may still enforce NPROC limit
 661          * for programs doing set*uid()+execve() by harmlessly deferring the
 662          * failure to the execve() stage.
 663          */
 664         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
 665                         new_user != INIT_USER)
 666                 current->flags |= PF_NPROC_EXCEEDED;
 667         else
 668                 current->flags &= ~PF_NPROC_EXCEEDED;
 669
 670         free_uid(new->user);
 671         new->user = new_user;
 672         return 0;
 673 }
 674
 675 /*
 676  * Unprivileged users may change the real uid to the effective uid
 677  * or vice versa.  (BSD-style)
 678  *
 679  * If you set the real uid at all, or set the effective uid to a value not
 680  * equal to the real uid, then the saved uid is set to the new effective uid.
 681  *
 682  * This makes it possible for a setuid program to completely drop its
 683  * privileges, which is often a useful assertion to make when you are doing
 684  * a security audit over a program.
 685  *
 686  * The general idea is that a program which uses just setreuid() will be
 687  * 100% compatible with BSD.  A program which uses just setuid() will be
 688  * 100% compatible with POSIX with saved IDs.
 689  */
 690 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 691 {
 692         struct user_namespace *ns = current_user_ns();
 693         const struct cred *old;
 694         struct cred *new;
 695         int retval;
 696         kuid_t kruid, keuid;
 697
 698         kruid = make_kuid(ns, ruid);
 699         keuid = make_kuid(ns, euid);
 700
 701         if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 702                 return -EINVAL;
 703         if ((euid != (uid_t) -1) && !uid_valid(keuid))
 704                 return -EINVAL;
 705
 706         new = prepare_creds();
 707         if (!new)
 708                 return -ENOMEM;
 709         old = current_cred();
 710
 711         retval = -EPERM;
 712         if (ruid != (uid_t) -1) {
 713                 new->uid = kruid;
 714                 if (!uid_eq(old->uid, kruid) &&
 715                     !uid_eq(old->euid, kruid) &&
 716                     !nsown_capable(CAP_SETUID))
 717                         goto error;
 718         }
 719
 720         if (euid != (uid_t) -1) {
 721                 new->euid = keuid;
 722                 if (!uid_eq(old->uid, keuid) &&
 723                     !uid_eq(old->euid, keuid) &&
 724                     !uid_eq(old->suid, keuid) &&
 725                     !nsown_capable(CAP_SETUID))
 726                         goto error;
 727         }
 728
 729         if (!uid_eq(new->uid, old->uid)) {
 730                 retval = set_user(new);
 731                 if (retval < 0)
 732                         goto error;
 733         }
 734         if (ruid != (uid_t) -1 ||
 735             (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
 736                 new->suid = new->euid;
 737         new->fsuid = new->euid;
 738
 739         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 740         if (retval < 0)
 741                 goto error;
 742
 743         return commit_creds(new);
 744
 745 error:
 746         abort_creds(new);
 747         return retval;
 748 }
 749
 750 /*
 751  * setuid() is implemented like SysV with SAVED_IDS
 752  *
 753  * Note that SAVED_ID's is deficient in that a setuid root program
 754  * like sendmail, for example, cannot set its uid to be a normal
 755  * user and then switch back, because if you're root, setuid() sets
 756  * the saved uid too.  If you don't like this, blame the bright people
 757  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 758  * will allow a root program to temporarily drop privileges and be able to
 759  * regain them by swapping the real and effective uid.
 760  */
 761 SYSCALL_DEFINE1(setuid, uid_t, uid)
 762 {
 763         struct user_namespace *ns = current_user_ns();
 764         const struct cred *old;
 765         struct cred *new;
 766         int retval;
 767         kuid_t kuid;
 768
 769         kuid = make_kuid(ns, uid);
 770         if (!uid_valid(kuid))
 771                 return -EINVAL;
 772
 773         new = prepare_creds();
 774         if (!new)
 775                 return -ENOMEM;
 776         old = current_cred();
 777
 778         retval = -EPERM;
 779         if (nsown_capable(CAP_SETUID)) {
 780                 new->suid = new->uid = kuid;
 781                 if (!uid_eq(kuid, old->uid)) {
 782                         retval = set_user(new);
 783                         if (retval < 0)
 784                                 goto error;
 785                 }
 786         } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
 787                 goto error;
 788         }
 789
 790         new->fsuid = new->euid = kuid;
 791
 792         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 793         if (retval < 0)
 794                 goto error;
 795
 796         return commit_creds(new);
 797
 798 error:
 799         abort_creds(new);
 800         return retval;
 801 }
 802
 803
 804 /*
 805  * This function implements a generic ability to update ruid, euid,
 806  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 807  */
 808 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 809 {
 810         struct user_namespace *ns = current_user_ns();
 811         const struct cred *old;
 812         struct cred *new;
 813         int retval;
 814         kuid_t kruid, keuid, ksuid;
 815
 816         kruid = make_kuid(ns, ruid);
 817         keuid = make_kuid(ns, euid);
 818         ksuid = make_kuid(ns, suid);
 819
 820         if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 821                 return -EINVAL;
 822
 823         if ((euid != (uid_t) -1) && !uid_valid(keuid))
 824                 return -EINVAL;
 825
 826         if ((suid != (uid_t) -1) && !uid_valid(ksuid))
 827                 return -EINVAL;
 828
 829         new = prepare_creds();
 830         if (!new)
 831                 return -ENOMEM;
 832
 833         old = current_cred();
 834
 835         retval = -EPERM;
 836         if (!nsown_capable(CAP_SETUID)) {
 837                 if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
 838                     !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
 839                         goto error;
 840                 if (euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
 841                     !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
 842                         goto error;
 843                 if (suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
 844                     !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
 845                         goto error;
 846         }
 847
 848         if (ruid != (uid_t) -1) {
 849                 new->uid = kruid;
 850                 if (!uid_eq(kruid, old->uid)) {
 851                         retval = set_user(new);
 852                         if (retval < 0)
 853                                 goto error;
 854                 }
 855         }
 856         if (euid != (uid_t) -1)
 857                 new->euid = keuid;
 858         if (suid != (uid_t) -1)
 859                 new->suid = ksuid;
 860         new->fsuid = new->euid;
 861
 862         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 863         if (retval < 0)
 864                 goto error;
 865
 866         return commit_creds(new);
 867
 868 error:
 869         abort_creds(new);
 870         return retval;
 871 }
 872
 873 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
 874 {
 875         const struct cred *cred = current_cred();
 876         int retval;
 877         uid_t ruid, euid, suid;
 878
 879         ruid = from_kuid_munged(cred->user_ns, cred->uid);
 880         euid = from_kuid_munged(cred->user_ns, cred->euid);
 881         suid = from_kuid_munged(cred->user_ns, cred->suid);
 882
 883         if (!(retval   = put_user(ruid, ruidp)) &&
 884             !(retval   = put_user(euid, euidp)))
 885                 retval = put_user(suid, suidp);
 886
 887         return retval;
 888 }
 889
 890 /*
 891  * Same as above, but for rgid, egid, sgid.
 892  */
 893 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 894 {
 895         struct user_namespace *ns = current_user_ns();
 896         const struct cred *old;
 897         struct cred *new;
 898         int retval;
 899         kgid_t krgid, kegid, ksgid;
 900
 901         krgid = make_kgid(ns, rgid);
 902         kegid = make_kgid(ns, egid);
 903         ksgid = make_kgid(ns, sgid);
 904
 905         if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 906                 return -EINVAL;
 907         if ((egid != (gid_t) -1) && !gid_valid(kegid))
 908                 return -EINVAL;
 909         if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
 910                 return -EINVAL;
 911
 912         new = prepare_creds();
 913         if (!new)
 914                 return -ENOMEM;
 915         old = current_cred();
 916
 917         retval = -EPERM;
 918         if (!nsown_capable(CAP_SETGID)) {
 919                 if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
 920                     !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
 921                         goto error;
 922                 if (egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
 923                     !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
 924                         goto error;
 925                 if (sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
 926                     !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
 927                         goto error;
 928         }
 929
 930         if (rgid != (gid_t) -1)
 931                 new->gid = krgid;
 932         if (egid != (gid_t) -1)
 933                 new->egid = kegid;
 934         if (sgid != (gid_t) -1)
 935                 new->sgid = ksgid;
 936         new->fsgid = new->egid;
 937
 938         return commit_creds(new);
 939
 940 error:
 941         abort_creds(new);
 942         return retval;
 943 }
 944
 945 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
 946 {
 947         const struct cred *cred = current_cred();
 948         int retval;
 949         gid_t rgid, egid, sgid;
 950
 951         rgid = from_kgid_munged(cred->user_ns, cred->gid);
 952         egid = from_kgid_munged(cred->user_ns, cred->egid);
 953         sgid = from_kgid_munged(cred->user_ns, cred->sgid);
 954
 955         if (!(retval   = put_user(rgid, rgidp)) &&
 956             !(retval   = put_user(egid, egidp)))
 957                 retval = put_user(sgid, sgidp);
 958
 959         return retval;
 960 }
 961
 962
 963 /*
 964  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 965  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 966  * whatever uid it wants to). It normally shadows "euid", except when
 967  * explicitly set by setfsuid() or for access..
 968  */
 969 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 970 {
 971         const struct cred *old;
 972         struct cred *new;
 973         uid_t old_fsuid;
 974         kuid_t kuid;
 975
 976         old = current_cred();
 977         old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
 978
 979         kuid = make_kuid(old->user_ns, uid);
 980         if (!uid_valid(kuid))
 981                 return old_fsuid;
 982
 983         new = prepare_creds();
 984         if (!new)
 985                 return old_fsuid;
 986
 987         if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
 988             uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
 989             nsown_capable(CAP_SETUID)) {
 990                 if (!uid_eq(kuid, old->fsuid)) {
 991                         new->fsuid = kuid;
 992                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 993                                 goto change_okay;
 994                 }
 995         }
 996
 997         abort_creds(new);
 998         return old_fsuid;
 999
1000 change_okay:
1001         commit_creds(new);
1002         return old_fsuid;
1003 }
1004
1005 /*
1006  * Samma på svenska..
1007  */
1008 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
1009 {
1010         const struct cred *old;
1011         struct cred *new;
1012         gid_t old_fsgid;
1013         kgid_t kgid;
1014
1015         old = current_cred();
1016         old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
1017
1018         kgid = make_kgid(old->user_ns, gid);
1019         if (!gid_valid(kgid))
1020                 return old_fsgid;
1021
1022         new = prepare_creds();
1023         if (!new)
1024                 return old_fsgid;
1025
1026         if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
1027             gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
1028             nsown_capable(CAP_SETGID)) {
1029                 if (!gid_eq(kgid, old->fsgid)) {
1030                         new->fsgid = kgid;
1031                         goto change_okay;
1032                 }
1033         }
1034
1035         abort_creds(new);
1036         return old_fsgid;
1037
1038 change_okay:
1039         commit_creds(new);
1040         return old_fsgid;
1041 }
1042
1043 void do_sys_times(struct tms *tms)
1044 {
1045         cputime_t tgutime, tgstime, cutime, cstime;
1046
1047         spin_lock_irq(&current->sighand->siglock);
1048         thread_group_times(current, &tgutime, &tgstime);
1049         cutime = current->signal->cutime;
1050         cstime = current->signal->cstime;
1051         spin_unlock_irq(&current->sighand->siglock);
1052         tms->tms_utime = cputime_to_clock_t(tgutime);
1053         tms->tms_stime = cputime_to_clock_t(tgstime);
1054         tms->tms_cutime = cputime_to_clock_t(cutime);
1055         tms->tms_cstime = cputime_to_clock_t(cstime);
1056 }
1057
1058 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
1059 {
1060         if (tbuf) {
1061                 struct tms tmp;
1062
1063                 do_sys_times(&tmp);
1064                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1065                         return -EFAULT;
1066         }
1067         force_successful_syscall_return();
1068         return (long) jiffies_64_to_clock_t(get_jiffies_64());
1069 }
1070
1071 /*
1072  * This needs some heavy checking ...
1073  * I just haven't the stomach for it. I also don't fully
1074  * understand sessions/pgrp etc. Let somebody who does explain it.
1075  *
1076  * OK, I think I have the protection semantics right.... this is really
1077  * only important on a multi-user system anyway, to make sure one user
1078  * can't send a signal to a process owned by another.  -TYT, 12/12/91
1079  *
1080  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1081  * LBT 04.03.94
1082  */
1083 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1084 {
1085         struct task_struct *p;
1086         struct task_struct *group_leader = current->group_leader;
1087         struct pid *pgrp;
1088         int err;
1089
1090         if (!pid)
1091                 pid = task_pid_vnr(group_leader);
1092         if (!pgid)
1093                 pgid = pid;
1094         if (pgid < 0)
1095                 return -EINVAL;
1096         rcu_read_lock();
1097
1098         /* From this point forward we keep holding onto the tasklist lock
1099          * so that our parent does not change from under us. -DaveM
1100          */
1101         write_lock_irq(&tasklist_lock);
1102
1103         err = -ESRCH;
1104         p = find_task_by_vpid(pid);
1105         if (!p)
1106                 goto out;
1107
1108         err = -EINVAL;
1109         if (!thread_group_leader(p))
1110                 goto out;
1111
1112         if (same_thread_group(p->real_parent, group_leader)) {
1113                 err = -EPERM;
1114                 if (task_session(p) != task_session(group_leader))
1115                         goto out;
1116                 err = -EACCES;
1117                 if (p->did_exec)
1118                         goto out;
1119         } else {
1120                 err = -ESRCH;
1121                 if (p != group_leader)
1122                         goto out;
1123         }
1124
1125         err = -EPERM;
1126         if (p->signal->leader)
1127                 goto out;
1128
1129         pgrp = task_pid(p);
1130         if (pgid != pid) {
1131                 struct task_struct *g;
1132
1133                 pgrp = find_vpid(pgid);
1134                 g = pid_task(pgrp, PIDTYPE_PGID);
1135                 if (!g || task_session(g) != task_session(group_leader))
1136                         goto out;
1137         }
1138
1139         err = security_task_setpgid(p, pgid);
1140         if (err)
1141                 goto out;
1142
1143         if (task_pgrp(p) != pgrp)
1144                 change_pid(p, PIDTYPE_PGID, pgrp);
1145
1146         err = 0;
1147 out:
1148         /* All paths lead to here, thus we are safe. -DaveM */
1149         write_unlock_irq(&tasklist_lock);
1150         rcu_read_unlock();
1151         return err;
1152 }
1153
1154 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1155 {
1156         struct task_struct *p;
1157         struct pid *grp;
1158         int retval;
1159
1160         rcu_read_lock();
1161         if (!pid)
1162                 grp = task_pgrp(current);
1163         else {
1164                 retval = -ESRCH;
1165                 p = find_task_by_vpid(pid);
1166                 if (!p)
1167                         goto out;
1168                 grp = task_pgrp(p);
1169                 if (!grp)
1170                         goto out;
1171
1172                 retval = security_task_getpgid(p);
1173                 if (retval)
1174                         goto out;
1175         }
1176         retval = pid_vnr(grp);
1177 out:
1178         rcu_read_unlock();
1179         return retval;
1180 }
1181
1182 #ifdef __ARCH_WANT_SYS_GETPGRP
1183
1184 SYSCALL_DEFINE0(getpgrp)
1185 {
1186         return sys_getpgid(0);
1187 }
1188
1189 #endif
1190
1191 SYSCALL_DEFINE1(getsid, pid_t, pid)
1192 {
1193         struct task_struct *p;
1194         struct pid *sid;
1195         int retval;
1196
1197         rcu_read_lock();
1198         if (!pid)
1199                 sid = task_session(current);
1200         else {
1201                 retval = -ESRCH;
1202                 p = find_task_by_vpid(pid);
1203                 if (!p)
1204                         goto out;
1205                 sid = task_session(p);
1206                 if (!sid)
1207                         goto out;
1208
1209                 retval = security_task_getsid(p);
1210                 if (retval)
1211                         goto out;
1212         }
1213         retval = pid_vnr(sid);
1214 out:
1215         rcu_read_unlock();
1216         return retval;
1217 }
1218
1219 SYSCALL_DEFINE0(setsid)
1220 {
1221         struct task_struct *group_leader = current->group_leader;
1222         struct pid *sid = task_pid(group_leader);
1223         pid_t session = pid_vnr(sid);
1224         int err = -EPERM;
1225
1226         write_lock_irq(&tasklist_lock);
1227         /* Fail if I am already a session leader */
1228         if (group_leader->signal->leader)
1229                 goto out;
1230
1231         /* Fail if a process group id already exists that equals the
1232          * proposed session id.
1233          */
1234         if (pid_task(sid, PIDTYPE_PGID))
1235                 goto out;
1236
1237         group_leader->signal->leader = 1;
1238         __set_special_pids(sid);
1239
1240         proc_clear_tty(group_leader);
1241
1242         err = session;
1243 out:
1244         write_unlock_irq(&tasklist_lock);
1245         if (err > 0) {
1246                 proc_sid_connector(group_leader);
1247                 sched_autogroup_create_attach(group_leader);
1248         }
1249         return err;
1250 }
1251
1252 DECLARE_RWSEM(uts_sem);
1253
1254 #ifdef COMPAT_UTS_MACHINE
1255 #define override_architecture(name) \
1256         (personality(current->personality) == PER_LINUX32 && \
1257          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1258                       sizeof(COMPAT_UTS_MACHINE)))
1259 #else
1260 #define override_architecture(name)     0
1261 #endif
1262
1263 /*
1264  * Work around broken programs that cannot handle "Linux 3.0".
1265  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1266  */
1267 static int override_release(char __user *release, int len)
1268 {
1269         int ret = 0;
1270         char buf[65];
1271
1272         if (current->personality & UNAME26) {
1273                 char *rest = UTS_RELEASE;
1274                 int ndots = 0;
1275                 unsigned v;
1276
1277                 while (*rest) {
1278                         if (*rest == '.' && ++ndots >= 3)
1279                                 break;
1280                         if (!isdigit(*rest) && *rest != '.')
1281                                 break;
1282                         rest++;
1283                 }
1284                 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1285                 snprintf(buf, len, "2.6.%u%s", v, rest);
1286                 ret = copy_to_user(release, buf, len);
1287         }
1288         return ret;
1289 }
1290
1291 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1292 {
1293         int errno = 0;
1294
1295         down_read(&uts_sem);
1296         if (copy_to_user(name, utsname(), sizeof *name))
1297                 errno = -EFAULT;
1298         up_read(&uts_sem);
1299
1300         if (!errno && override_release(name->release, sizeof(name->release)))
1301                 errno = -EFAULT;
1302         if (!errno && override_architecture(name))
1303                 errno = -EFAULT;
1304         return errno;
1305 }
1306
1307 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1308 /*
1309  * Old cruft
1310  */
1311 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1312 {
1313         int error = 0;
1314
1315         if (!name)
1316                 return -EFAULT;
1317
1318         down_read(&uts_sem);
1319         if (copy_to_user(name, utsname(), sizeof(*name)))
1320                 error = -EFAULT;
1321         up_read(&uts_sem);
1322
1323         if (!error && override_release(name->release, sizeof(name->release)))
1324                 error = -EFAULT;
1325         if (!error && override_architecture(name))
1326                 error = -EFAULT;
1327         return error;
1328 }
1329
1330 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1331 {
1332         int error;
1333
1334         if (!name)
1335                 return -EFAULT;
1336         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1337                 return -EFAULT;
1338
1339         down_read(&uts_sem);
1340         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1341                                __OLD_UTS_LEN);
1342         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1343         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1344                                 __OLD_UTS_LEN);
1345         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1346         error |= __copy_to_user(&name->release, &utsname()->release,
1347                                 __OLD_UTS_LEN);
1348         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1349         error |= __copy_to_user(&name->version, &utsname()->version,
1350                                 __OLD_UTS_LEN);
1351         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1352         error |= __copy_to_user(&name->machine, &utsname()->machine,
1353                                 __OLD_UTS_LEN);
1354         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1355         up_read(&uts_sem);
1356
1357         if (!error && override_architecture(name))
1358                 error = -EFAULT;
1359         if (!error && override_release(name->release, sizeof(name->release)))
1360                 error = -EFAULT;
1361         return error ? -EFAULT : 0;
1362 }
1363 #endif
1364
1365 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1366 {
1367         int errno;
1368         char tmp[__NEW_UTS_LEN];
1369
1370         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1371                 return -EPERM;
1372
1373         if (len < 0 || len > __NEW_UTS_LEN)
1374                 return -EINVAL;
1375         down_write(&uts_sem);
1376         errno = -EFAULT;
1377         if (!copy_from_user(tmp, name, len)) {
1378                 struct new_utsname *u = utsname();
1379
1380                 memcpy(u->nodename, tmp, len);
1381                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1382                 errno = 0;
1383                 uts_proc_notify(UTS_PROC_HOSTNAME);
1384         }
1385         up_write(&uts_sem);
1386         return errno;
1387 }
1388
1389 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1390
1391 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1392 {
1393         int i, errno;
1394         struct new_utsname *u;
1395
1396         if (len < 0)
1397                 return -EINVAL;
1398         down_read(&uts_sem);
1399         u = utsname();
1400         i = 1 + strlen(u->nodename);
1401         if (i > len)
1402                 i = len;
1403         errno = 0;
1404         if (copy_to_user(name, u->nodename, i))
1405                 errno = -EFAULT;
1406         up_read(&uts_sem);
1407         return errno;
1408 }
1409
1410 #endif
1411
1412 /*
1413  * Only setdomainname; getdomainname can be implemented by calling
1414  * uname()
1415  */
1416 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1417 {
1418         int errno;
1419         char tmp[__NEW_UTS_LEN];
1420
1421         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1422                 return -EPERM;
1423         if (len < 0 || len > __NEW_UTS_LEN)
1424                 return -EINVAL;
1425
1426         down_write(&uts_sem);
1427         errno = -EFAULT;
1428         if (!copy_from_user(tmp, name, len)) {
1429                 struct new_utsname *u = utsname();
1430
1431                 memcpy(u->domainname, tmp, len);
1432                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1433                 errno = 0;
1434                 uts_proc_notify(UTS_PROC_DOMAINNAME);
1435         }
1436         up_write(&uts_sem);
1437         return errno;
1438 }
1439
1440 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1441 {
1442         struct rlimit value;
1443         int ret;
1444
1445         ret = do_prlimit(current, resource, NULL, &value);
1446         if (!ret)
1447                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1448
1449         return ret;
1450 }
1451
1452 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1453
1454 /*
1455  *      Back compatibility for getrlimit. Needed for some apps.
1456  */
1457
1458 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1459                 struct rlimit __user *, rlim)
1460 {
1461         struct rlimit x;
1462         if (resource >= RLIM_NLIMITS)
1463                 return -EINVAL;
1464
1465         task_lock(current->group_leader);
1466         x = current->signal->rlim[resource];
1467         task_unlock(current->group_leader);
1468         if (x.rlim_cur > 0x7FFFFFFF)
1469                 x.rlim_cur = 0x7FFFFFFF;
1470         if (x.rlim_max > 0x7FFFFFFF)
1471                 x.rlim_max = 0x7FFFFFFF;
1472         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1473 }
1474
1475 #endif
1476
1477 static inline bool rlim64_is_infinity(__u64 rlim64)
1478 {
1479 #if BITS_PER_LONG < 64
1480         return rlim64 >= ULONG_MAX;
1481 #else
1482         return rlim64 == RLIM64_INFINITY;
1483 #endif
1484 }
1485
1486 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1487 {
1488         if (rlim->rlim_cur == RLIM_INFINITY)
1489                 rlim64->rlim_cur = RLIM64_INFINITY;
1490         else
1491                 rlim64->rlim_cur = rlim->rlim_cur;
1492         if (rlim->rlim_max == RLIM_INFINITY)
1493                 rlim64->rlim_max = RLIM64_INFINITY;
1494         else
1495                 rlim64->rlim_max = rlim->rlim_max;
1496 }
1497
1498 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1499 {
1500         if (rlim64_is_infinity(rlim64->rlim_cur))
1501                 rlim->rlim_cur = RLIM_INFINITY;
1502         else
1503                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1504         if (rlim64_is_infinity(rlim64->rlim_max))
1505                 rlim->rlim_max = RLIM_INFINITY;
1506         else
1507                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1508 }
1509
1510 /* make sure you are allowed to change @tsk limits before calling this */
1511 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1512                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1513 {
1514         struct rlimit *rlim;
1515         int retval = 0;
1516
1517         if (resource >= RLIM_NLIMITS)
1518                 return -EINVAL;
1519         if (new_rlim) {
1520                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1521                         return -EINVAL;
1522                 if (resource == RLIMIT_NOFILE &&
1523                                 new_rlim->rlim_max > sysctl_nr_open)
1524                         return -EPERM;
1525         }
1526
1527         /* protect tsk->signal and tsk->sighand from disappearing */
1528         read_lock(&tasklist_lock);
1529         if (!tsk->sighand) {
1530                 retval = -ESRCH;
1531                 goto out;
1532         }
1533
1534         rlim = tsk->signal->rlim + resource;
1535         task_lock(tsk->group_leader);
1536         if (new_rlim) {
1537                 /* Keep the capable check against init_user_ns until
1538                    cgroups can contain all limits */
1539                 if (new_rlim->rlim_max > rlim->rlim_max &&
1540                                 !capable(CAP_SYS_RESOURCE))
1541                         retval = -EPERM;
1542                 if (!retval)
1543                         retval = security_task_setrlimit(tsk->group_leader,
1544                                         resource, new_rlim);
1545                 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1546                         /*
1547                          * The caller is asking for an immediate RLIMIT_CPU
1548                          * expiry.  But we use the zero value to mean "it was
1549                          * never set".  So let's cheat and make it one second
1550                          * instead
1551                          */
1552                         new_rlim->rlim_cur = 1;
1553                 }
1554         }
1555         if (!retval) {
1556                 if (old_rlim)
1557                         *old_rlim = *rlim;
1558                 if (new_rlim)
1559                         *rlim = *new_rlim;
1560         }
1561         task_unlock(tsk->group_leader);
1562
1563         /*
1564          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1565          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1566          * very long-standing error, and fixing it now risks breakage of
1567          * applications, so we live with it
1568          */
1569          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1570                          new_rlim->rlim_cur != RLIM_INFINITY)
1571                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1572 out:
1573         read_unlock(&tasklist_lock);
1574         return retval;
1575 }
1576
1577 /* rcu lock must be held */
1578 static int check_prlimit_permission(struct task_struct *task)
1579 {
1580         const struct cred *cred = current_cred(), *tcred;
1581
1582         if (current == task)
1583                 return 0;
1584
1585         tcred = __task_cred(task);
1586         if (uid_eq(cred->uid, tcred->euid) &&
1587             uid_eq(cred->uid, tcred->suid) &&
1588             uid_eq(cred->uid, tcred->uid)  &&
1589             gid_eq(cred->gid, tcred->egid) &&
1590             gid_eq(cred->gid, tcred->sgid) &&
1591             gid_eq(cred->gid, tcred->gid))
1592                 return 0;
1593         if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1594                 return 0;
1595
1596         return -EPERM;
1597 }
1598
1599 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1600                 const struct rlimit64 __user *, new_rlim,
1601                 struct rlimit64 __user *, old_rlim)
1602 {
1603         struct rlimit64 old64, new64;
1604         struct rlimit old, new;
1605         struct task_struct *tsk;
1606         int ret;
1607
1608         if (new_rlim) {
1609                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1610                         return -EFAULT;
1611                 rlim64_to_rlim(&new64, &new);
1612         }
1613
1614         rcu_read_lock();
1615         tsk = pid ? find_task_by_vpid(pid) : current;
1616         if (!tsk) {
1617                 rcu_read_unlock();
1618                 return -ESRCH;
1619         }
1620         ret = check_prlimit_permission(tsk);
1621         if (ret) {
1622                 rcu_read_unlock();
1623                 return ret;
1624         }
1625         get_task_struct(tsk);
1626         rcu_read_unlock();
1627
1628         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1629                         old_rlim ? &old : NULL);
1630
1631         if (!ret && old_rlim) {
1632                 rlim_to_rlim64(&old, &old64);
1633                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1634                         ret = -EFAULT;
1635         }
1636
1637         put_task_struct(tsk);
1638         return ret;
1639 }
1640
1641 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1642 {
1643         struct rlimit new_rlim;
1644
1645         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1646                 return -EFAULT;
1647         return do_prlimit(current, resource, &new_rlim, NULL);
1648 }
1649
1650 /*
1651  * It would make sense to put struct rusage in the task_struct,
1652  * except that would make the task_struct be *really big*.  After
1653  * task_struct gets moved into malloc'ed memory, it would
1654  * make sense to do this.  It will make moving the rest of the information
1655  * a lot simpler!  (Which we're not doing right now because we're not
1656  * measuring them yet).
1657  *
1658  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1659  * races with threads incrementing their own counters.  But since word
1660  * reads are atomic, we either get new values or old values and we don't
1661  * care which for the sums.  We always take the siglock to protect reading
1662  * the c* fields from p->signal from races with exit.c updating those
1663  * fields when reaping, so a sample either gets all the additions of a
1664  * given child after it's reaped, or none so this sample is before reaping.
1665  *
1666  * Locking:
1667  * We need to take the siglock for CHILDEREN, SELF and BOTH
1668  * for  the cases current multithreaded, non-current single threaded
1669  * non-current multithreaded.  Thread traversal is now safe with
1670  * the siglock held.
1671  * Strictly speaking, we donot need to take the siglock if we are current and
1672  * single threaded,  as no one else can take our signal_struct away, no one
1673  * else can  reap the  children to update signal->c* counters, and no one else
1674  * can race with the signal-> fields. If we do not take any lock, the
1675  * signal-> fields could be read out of order while another thread was just
1676  * exiting. So we should  place a read memory barrier when we avoid the lock.
1677  * On the writer side,  write memory barrier is implied in  __exit_signal
1678  * as __exit_signal releases  the siglock spinlock after updating the signal->
1679  * fields. But we don't do this yet to keep things simple.
1680  *
1681  */
1682
1683 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1684 {
1685         r->ru_nvcsw += t->nvcsw;
1686         r->ru_nivcsw += t->nivcsw;
1687         r->ru_minflt += t->min_flt;
1688         r->ru_majflt += t->maj_flt;
1689         r->ru_inblock += task_io_get_inblock(t);
1690         r->ru_oublock += task_io_get_oublock(t);
1691 }
1692
1693 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1694 {
1695         struct task_struct *t;
1696         unsigned long flags;
1697         cputime_t tgutime, tgstime, utime, stime;
1698         unsigned long maxrss = 0;
1699
1700         memset((char *) r, 0, sizeof *r);
1701         utime = stime = 0;
1702
1703         if (who == RUSAGE_THREAD) {
1704                 task_times(current, &utime, &stime);
1705                 accumulate_thread_rusage(p, r);
1706                 maxrss = p->signal->maxrss;
1707                 goto out;
1708         }
1709
1710         if (!lock_task_sighand(p, &flags))
1711                 return;
1712
1713         switch (who) {
1714                 case RUSAGE_BOTH:
1715                 case RUSAGE_CHILDREN:
1716                         utime = p->signal->cutime;
1717                         stime = p->signal->cstime;
1718                         r->ru_nvcsw = p->signal->cnvcsw;
1719                         r->ru_nivcsw = p->signal->cnivcsw;
1720                         r->ru_minflt = p->signal->cmin_flt;
1721                         r->ru_majflt = p->signal->cmaj_flt;
1722                         r->ru_inblock = p->signal->cinblock;
1723                         r->ru_oublock = p->signal->coublock;
1724                         maxrss = p->signal->cmaxrss;
1725
1726                         if (who == RUSAGE_CHILDREN)
1727                                 break;
1728
1729                 case RUSAGE_SELF:
1730                         thread_group_times(p, &tgutime, &tgstime);
1731                         utime += tgutime;
1732                         stime += tgstime;
1733                         r->ru_nvcsw += p->signal->nvcsw;
1734                         r->ru_nivcsw += p->signal->nivcsw;
1735                         r->ru_minflt += p->signal->min_flt;
1736                         r->ru_majflt += p->signal->maj_flt;
1737                         r->ru_inblock += p->signal->inblock;
1738                         r->ru_oublock += p->signal->oublock;
1739                         if (maxrss < p->signal->maxrss)
1740                                 maxrss = p->signal->maxrss;
1741                         t = p;
1742                         do {
1743                                 accumulate_thread_rusage(t, r);
1744                                 t = next_thread(t);
1745                         } while (t != p);
1746                         break;
1747
1748                 default:
1749                         BUG();
1750         }
1751         unlock_task_sighand(p, &flags);
1752
1753 out:
1754         cputime_to_timeval(utime, &r->ru_utime);
1755         cputime_to_timeval(stime, &r->ru_stime);
1756
1757         if (who != RUSAGE_CHILDREN) {
1758                 struct mm_struct *mm = get_task_mm(p);
1759                 if (mm) {
1760                         setmax_mm_hiwater_rss(&maxrss, mm);
1761                         mmput(mm);
1762                 }
1763         }
1764         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1765 }
1766
1767 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1768 {
1769         struct rusage r;
1770         k_getrusage(p, who, &r);
1771         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1772 }
1773
1774 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1775 {
1776         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1777             who != RUSAGE_THREAD)
1778                 return -EINVAL;
1779         return getrusage(current, who, ru);
1780 }
1781
1782 SYSCALL_DEFINE1(umask, int, mask)
1783 {
1784         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1785         return mask;
1786 }
1787
1788 #ifdef CONFIG_CHECKPOINT_RESTORE
1789 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1790 {
1791         struct file *exe_file;
1792         struct dentry *dentry;
1793         int err;
1794
1795         exe_file = fget(fd);
1796         if (!exe_file)
1797                 return -EBADF;
1798
1799         dentry = exe_file->f_path.dentry;
1800
1801         /*
1802          * Because the original mm->exe_file points to executable file, make
1803          * sure that this one is executable as well, to avoid breaking an
1804          * overall picture.
1805          */
1806         err = -EACCES;
1807         if (!S_ISREG(dentry->d_inode->i_mode)   ||
1808             exe_file->f_path.mnt->mnt_flags & MNT_NOEXEC)
1809                 goto exit;
1810
1811         err = inode_permission(dentry->d_inode, MAY_EXEC);
1812         if (err)
1813                 goto exit;
1814
1815         down_write(&mm->mmap_sem);
1816
1817         /*
1818          * Forbid mm->exe_file change if old file still mapped.
1819          */
1820         err = -EBUSY;
1821         if (mm->exe_file) {
1822                 struct vm_area_struct *vma;
1823
1824                 for (vma = mm->mmap; vma; vma = vma->vm_next)
1825                         if (vma->vm_file &&
1826                             path_equal(&vma->vm_file->f_path,
1827                                        &mm->exe_file->f_path))
1828                                 goto exit_unlock;
1829         }
1830
1831         /*
1832          * The symlink can be changed only once, just to disallow arbitrary
1833          * transitions malicious software might bring in. This means one
1834          * could make a snapshot over all processes running and monitor
1835          * /proc/pid/exe changes to notice unusual activity if needed.
1836          */
1837         err = -EPERM;
1838         if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
1839                 goto exit_unlock;
1840
1841         err = 0;
1842         set_mm_exe_file(mm, exe_file);
1843 exit_unlock:
1844         up_write(&mm->mmap_sem);
1845
1846 exit:
1847         fput(exe_file);
1848         return err;
1849 }
1850
1851 static int prctl_set_mm(int opt, unsigned long addr,
1852                         unsigned long arg4, unsigned long arg5)
1853 {
1854         unsigned long rlim = rlimit(RLIMIT_DATA);
1855         struct mm_struct *mm = current->mm;
1856         struct vm_area_struct *vma;
1857         int error;
1858
1859         if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
1860                 return -EINVAL;
1861
1862         if (!capable(CAP_SYS_RESOURCE))
1863                 return -EPERM;
1864
1865         if (opt == PR_SET_MM_EXE_FILE)
1866                 return prctl_set_mm_exe_file(mm, (unsigned int)addr);
1867
1868         if (addr >= TASK_SIZE || addr < mmap_min_addr)
1869                 return -EINVAL;
1870
1871         error = -EINVAL;
1872
1873         down_read(&mm->mmap_sem);
1874         vma = find_vma(mm, addr);
1875
1876         switch (opt) {
1877         case PR_SET_MM_START_CODE:
1878                 mm->start_code = addr;
1879                 break;
1880         case PR_SET_MM_END_CODE:
1881                 mm->end_code = addr;
1882                 break;
1883         case PR_SET_MM_START_DATA:
1884                 mm->start_data = addr;
1885                 break;
1886         case PR_SET_MM_END_DATA:
1887                 mm->end_data = addr;
1888                 break;
1889
1890         case PR_SET_MM_START_BRK:
1891                 if (addr <= mm->end_data)
1892                         goto out;
1893
1894                 if (rlim < RLIM_INFINITY &&
1895                     (mm->brk - addr) +
1896                     (mm->end_data - mm->start_data) > rlim)
1897                         goto out;
1898
1899                 mm->start_brk = addr;
1900                 break;
1901
1902         case PR_SET_MM_BRK:
1903                 if (addr <= mm->end_data)
1904                         goto out;
1905
1906                 if (rlim < RLIM_INFINITY &&
1907                     (addr - mm->start_brk) +
1908                     (mm->end_data - mm->start_data) > rlim)
1909                         goto out;
1910
1911                 mm->brk = addr;
1912                 break;
1913
1914         /*
1915          * If command line arguments and environment
1916          * are placed somewhere else on stack, we can
1917          * set them up here, ARG_START/END to setup
1918          * command line argumets and ENV_START/END
1919          * for environment.
1920          */
1921         case PR_SET_MM_START_STACK:
1922         case PR_SET_MM_ARG_START:
1923         case PR_SET_MM_ARG_END:
1924         case PR_SET_MM_ENV_START:
1925         case PR_SET_MM_ENV_END:
1926                 if (!vma) {
1927                         error = -EFAULT;
1928                         goto out;
1929                 }
1930                 if (opt == PR_SET_MM_START_STACK)
1931                         mm->start_stack = addr;
1932                 else if (opt == PR_SET_MM_ARG_START)
1933                         mm->arg_start = addr;
1934                 else if (opt == PR_SET_MM_ARG_END)
1935                         mm->arg_end = addr;
1936                 else if (opt == PR_SET_MM_ENV_START)
1937                         mm->env_start = addr;
1938                 else if (opt == PR_SET_MM_ENV_END)
1939                         mm->env_end = addr;
1940                 break;
1941
1942         /*
1943          * This doesn't move auxiliary vector itself
1944          * since it's pinned to mm_struct, but allow
1945          * to fill vector with new values. It's up
1946          * to a caller to provide sane values here
1947          * otherwise user space tools which use this
1948          * vector might be unhappy.
1949          */
1950         case PR_SET_MM_AUXV: {
1951                 unsigned long user_auxv[AT_VECTOR_SIZE];
1952
1953                 if (arg4 > sizeof(user_auxv))
1954                         goto out;
1955                 up_read(&mm->mmap_sem);
1956
1957                 if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
1958                         return -EFAULT;
1959
1960                 /* Make sure the last entry is always AT_NULL */
1961                 user_auxv[AT_VECTOR_SIZE - 2] = 0;
1962                 user_auxv[AT_VECTOR_SIZE - 1] = 0;
1963
1964                 BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1965
1966                 task_lock(current);
1967                 memcpy(mm->saved_auxv, user_auxv, arg4);
1968                 task_unlock(current);
1969
1970                 return 0;
1971         }
1972         default:
1973                 goto out;
1974         }
1975
1976         error = 0;
1977 out:
1978         up_read(&mm->mmap_sem);
1979         return error;
1980 }
1981
1982 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1983 {
1984         return put_user(me->clear_child_tid, tid_addr);
1985 }
1986
1987 #else /* CONFIG_CHECKPOINT_RESTORE */
1988 static int prctl_set_mm(int opt, unsigned long addr,
1989                         unsigned long arg4, unsigned long arg5)
1990 {
1991         return -EINVAL;
1992 }
1993 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1994 {
1995         return -EINVAL;
1996 }
1997 #endif
1998
1999 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2000                 unsigned long, arg4, unsigned long, arg5)
2001 {
2002         struct task_struct *me = current;
2003         unsigned char comm[sizeof(me->comm)];
2004         long error;
2005
2006         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2007         if (error != -ENOSYS)
2008                 return error;
2009
2010         error = 0;
2011         switch (option) {
2012                 case PR_SET_PDEATHSIG:
2013                         if (!valid_signal(arg2)) {
2014                                 error = -EINVAL;
2015                                 break;
2016                         }
2017                         me->pdeath_signal = arg2;
2018                         break;
2019                 case PR_GET_PDEATHSIG:
2020                         error = put_user(me->pdeath_signal, (int __user *)arg2);
2021                         break;
2022                 case PR_GET_DUMPABLE:
2023                         error = get_dumpable(me->mm);
2024                         break;
2025                 case PR_SET_DUMPABLE:
2026                         if (arg2 < 0 || arg2 > 1) {
2027                                 error = -EINVAL;
2028                                 break;
2029                         }
2030                         set_dumpable(me->mm, arg2);
2031                         break;
2032
2033                 case PR_SET_UNALIGN:
2034                         error = SET_UNALIGN_CTL(me, arg2);
2035                         break;
2036                 case PR_GET_UNALIGN:
2037                         error = GET_UNALIGN_CTL(me, arg2);
2038                         break;
2039                 case PR_SET_FPEMU:
2040                         error = SET_FPEMU_CTL(me, arg2);
2041                         break;
2042                 case PR_GET_FPEMU:
2043                         error = GET_FPEMU_CTL(me, arg2);
2044                         break;
2045                 case PR_SET_FPEXC:
2046                         error = SET_FPEXC_CTL(me, arg2);
2047                         break;
2048                 case PR_GET_FPEXC:
2049                         error = GET_FPEXC_CTL(me, arg2);
2050                         break;
2051                 case PR_GET_TIMING:
2052                         error = PR_TIMING_STATISTICAL;
2053                         break;
2054                 case PR_SET_TIMING:
2055                         if (arg2 != PR_TIMING_STATISTICAL)
2056                                 error = -EINVAL;
2057                         break;
2058                 case PR_SET_NAME:
2059                         comm[sizeof(me->comm)-1] = 0;
2060                         if (strncpy_from_user(comm, (char __user *)arg2,
2061                                               sizeof(me->comm) - 1) < 0)
2062                                 return -EFAULT;
2063                         set_task_comm(me, comm);
2064                         proc_comm_connector(me);
2065                         break;
2066                 case PR_GET_NAME:
2067                         get_task_comm(comm, me);
2068                         if (copy_to_user((char __user *)arg2, comm,
2069                                          sizeof(comm)))
2070                                 return -EFAULT;
2071                         break;
2072                 case PR_GET_ENDIAN:
2073                         error = GET_ENDIAN(me, arg2);
2074                         break;
2075                 case PR_SET_ENDIAN:
2076                         error = SET_ENDIAN(me, arg2);
2077                         break;
2078                 case PR_GET_SECCOMP:
2079                         error = prctl_get_seccomp();
2080                         break;
2081                 case PR_SET_SECCOMP:
2082                         error = prctl_set_seccomp(arg2, (char __user *)arg3);
2083                         break;
2084                 case PR_GET_TSC:
2085                         error = GET_TSC_CTL(arg2);
2086                         break;
2087                 case PR_SET_TSC:
2088                         error = SET_TSC_CTL(arg2);
2089                         break;
2090                 case PR_TASK_PERF_EVENTS_DISABLE:
2091                         error = perf_event_task_disable();
2092                         break;
2093                 case PR_TASK_PERF_EVENTS_ENABLE:
2094                         error = perf_event_task_enable();
2095                         break;
2096                 case PR_GET_TIMERSLACK:
2097                         error = current->timer_slack_ns;
2098                         break;
2099                 case PR_SET_TIMERSLACK:
2100                         if (arg2 <= 0)
2101                                 current->timer_slack_ns =
2102                                         current->default_timer_slack_ns;
2103                         else
2104                                 current->timer_slack_ns = arg2;
2105                         break;
2106                 case PR_MCE_KILL:
2107                         if (arg4 | arg5)
2108                                 return -EINVAL;
2109                         switch (arg2) {
2110                         case PR_MCE_KILL_CLEAR:
2111                                 if (arg3 != 0)
2112                                         return -EINVAL;
2113                                 current->flags &= ~PF_MCE_PROCESS;
2114                                 break;
2115                         case PR_MCE_KILL_SET:
2116                                 current->flags |= PF_MCE_PROCESS;
2117                                 if (arg3 == PR_MCE_KILL_EARLY)
2118                                         current->flags |= PF_MCE_EARLY;
2119                                 else if (arg3 == PR_MCE_KILL_LATE)
2120                                         current->flags &= ~PF_MCE_EARLY;
2121                                 else if (arg3 == PR_MCE_KILL_DEFAULT)
2122                                         current->flags &=
2123                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
2124                                 else
2125                                         return -EINVAL;
2126                                 break;
2127                         default:
2128                                 return -EINVAL;
2129                         }
2130                         break;
2131                 case PR_MCE_KILL_GET:
2132                         if (arg2 | arg3 | arg4 | arg5)
2133                                 return -EINVAL;
2134                         if (current->flags & PF_MCE_PROCESS)
2135                                 error = (current->flags & PF_MCE_EARLY) ?
2136                                         PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2137                         else
2138                                 error = PR_MCE_KILL_DEFAULT;
2139                         break;
2140                 case PR_SET_MM:
2141                         error = prctl_set_mm(arg2, arg3, arg4, arg5);
2142                         break;
2143                 case PR_GET_TID_ADDRESS:
2144                         error = prctl_get_tid_address(me, (int __user **)arg2);
2145                         break;
2146                 case PR_SET_CHILD_SUBREAPER:
2147                         me->signal->is_child_subreaper = !!arg2;
2148                         break;
2149                 case PR_GET_CHILD_SUBREAPER:
2150                         error = put_user(me->signal->is_child_subreaper,
2151                                          (int __user *) arg2);
2152                         break;
2153                 case PR_SET_NO_NEW_PRIVS:
2154                         if (arg2 != 1 || arg3 || arg4 || arg5)
2155                                 return -EINVAL;
2156
2157                         current->no_new_privs = 1;
2158                         break;
2159                 case PR_GET_NO_NEW_PRIVS:
2160                         if (arg2 || arg3 || arg4 || arg5)
2161                                 return -EINVAL;
2162                         return current->no_new_privs ? 1 : 0;
2163                 default:
2164                         error = -EINVAL;
2165                         break;
2166         }
2167         return error;
2168 }
2169
2170 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2171                 struct getcpu_cache __user *, unused)
2172 {
2173         int err = 0;
2174         int cpu = raw_smp_processor_id();
2175         if (cpup)
2176                 err |= put_user(cpu, cpup);
2177         if (nodep)
2178                 err |= put_user(cpu_to_node(cpu), nodep);
2179         return err ? -EFAULT : 0;
2180 }
2181
2182 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
2183
2184 static void argv_cleanup(struct subprocess_info *info)
2185 {
2186         argv_free(info->argv);
2187 }
2188
2189 static int __orderly_poweroff(void)
2190 {
2191         int argc;
2192         char **argv;
2193         static char *envp[] = {
2194                 "HOME=/",
2195                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2196                 NULL
2197         };
2198         int ret;
2199
2200         argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
2201         if (argv == NULL) {
2202                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2203                        __func__, poweroff_cmd);
2204                 return -ENOMEM;
2205         }
2206
2207         ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_NO_WAIT,
2208                                       NULL, argv_cleanup, NULL);
2209         if (ret == -ENOMEM)
2210                 argv_free(argv);
2211
2212         return ret;
2213 }
2214
2215 /**
2216  * orderly_poweroff - Trigger an orderly system poweroff
2217  * @force: force poweroff if command execution fails
2218  *
2219  * This may be called from any context to trigger a system shutdown.
2220  * If the orderly shutdown fails, it will force an immediate shutdown.
2221  */
2222 int orderly_poweroff(bool force)
2223 {
2224         int ret = __orderly_poweroff();
2225
2226         if (ret && force) {
2227                 printk(KERN_WARNING "Failed to start orderly shutdown: "
2228                        "forcing the issue\n");
2229
2230                 /*
2231                  * I guess this should try to kick off some daemon to sync and
2232                  * poweroff asap.  Or not even bother syncing if we're doing an
2233                  * emergency shutdown?
2234                  */
2235                 emergency_sync();
2236                 kernel_power_off();
2237         }
2238
2239         return ret;
2240 }
2241 EXPORT_SYMBOL_GPL(orderly_poweroff);