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         disable_nonboot_cpus();
 372         if (!cmd)
 373                 printk(KERN_EMERG "Restarting system.\n");
 374         else
 375                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 376         kmsg_dump(KMSG_DUMP_RESTART);
 377         machine_restart(cmd);
 378 }
 379 EXPORT_SYMBOL_GPL(kernel_restart);
 380
 381 static void kernel_shutdown_prepare(enum system_states state)
 382 {
 383         blocking_notifier_call_chain(&reboot_notifier_list,
 384                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 385         system_state = state;
 386         usermodehelper_disable();
 387         device_shutdown();
 388 }
 389 /**
 390  *      kernel_halt - halt the system
 391  *
 392  *      Shutdown everything and perform a clean system halt.
 393  */
 394 void kernel_halt(void)
 395 {
 396         kernel_shutdown_prepare(SYSTEM_HALT);
 397         syscore_shutdown();
 398         printk(KERN_EMERG "System halted.\n");
 399         kmsg_dump(KMSG_DUMP_HALT);
 400         machine_halt();
 401 }
 402
 403 EXPORT_SYMBOL_GPL(kernel_halt);
 404
 405 /**
 406  *      kernel_power_off - power_off the system
 407  *
 408  *      Shutdown everything and perform a clean system power_off.
 409  */
 410 void kernel_power_off(void)
 411 {
 412         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 413         if (pm_power_off_prepare)
 414                 pm_power_off_prepare();
 415         disable_nonboot_cpus();
 416         syscore_shutdown();
 417         printk(KERN_EMERG "Power down.\n");
 418         kmsg_dump(KMSG_DUMP_POWEROFF);
 419         machine_power_off();
 420 }
 421 EXPORT_SYMBOL_GPL(kernel_power_off);
 422
 423 static DEFINE_MUTEX(reboot_mutex);
 424
 425 /*
 426  * Reboot system call: for obvious reasons only root may call it,
 427  * and even root needs to set up some magic numbers in the registers
 428  * so that some mistake won't make this reboot the whole machine.
 429  * You can also set the meaning of the ctrl-alt-del-key here.
 430  *
 431  * reboot doesn't sync: do that yourself before calling this.
 432  */
 433 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 434                 void __user *, arg)
 435 {
 436         char buffer[256];
 437         int ret = 0;
 438
 439         /* We only trust the superuser with rebooting the system. */
 440         if (!capable(CAP_SYS_BOOT))
 441                 return -EPERM;
 442
 443         /* For safety, we require "magic" arguments. */
 444         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 445             (magic2 != LINUX_REBOOT_MAGIC2 &&
 446                         magic2 != LINUX_REBOOT_MAGIC2A &&
 447                         magic2 != LINUX_REBOOT_MAGIC2B &&
 448                         magic2 != LINUX_REBOOT_MAGIC2C))
 449                 return -EINVAL;
 450
 451         /*
 452          * If pid namespaces are enabled and the current task is in a child
 453          * pid_namespace, the command is handled by reboot_pid_ns() which will
 454          * call do_exit().
 455          */
 456         ret = reboot_pid_ns(task_active_pid_ns(current), cmd);
 457         if (ret)
 458                 return ret;
 459
 460         /* Instead of trying to make the power_off code look like
 461          * halt when pm_power_off is not set do it the easy way.
 462          */
 463         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 464                 cmd = LINUX_REBOOT_CMD_HALT;
 465
 466         mutex_lock(&reboot_mutex);
 467         switch (cmd) {
 468         case LINUX_REBOOT_CMD_RESTART:
 469                 kernel_restart(NULL);
 470                 break;
 471
 472         case LINUX_REBOOT_CMD_CAD_ON:
 473                 C_A_D = 1;
 474                 break;
 475
 476         case LINUX_REBOOT_CMD_CAD_OFF:
 477                 C_A_D = 0;
 478                 break;
 479
 480         case LINUX_REBOOT_CMD_HALT:
 481                 kernel_halt();
 482                 do_exit(0);
 483                 panic("cannot halt");
 484
 485         case LINUX_REBOOT_CMD_POWER_OFF:
 486                 kernel_power_off();
 487                 do_exit(0);
 488                 break;
 489
 490         case LINUX_REBOOT_CMD_RESTART2:
 491                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 492                         ret = -EFAULT;
 493                         break;
 494                 }
 495                 buffer[sizeof(buffer) - 1] = '\0';
 496
 497                 kernel_restart(buffer);
 498                 break;
 499
 500 #ifdef CONFIG_KEXEC
 501         case LINUX_REBOOT_CMD_KEXEC:
 502                 ret = kernel_kexec();
 503                 break;
 504 #endif
 505
 506 #ifdef CONFIG_HIBERNATION
 507         case LINUX_REBOOT_CMD_SW_SUSPEND:
 508                 ret = hibernate();
 509                 break;
 510 #endif
 511
 512         default:
 513                 ret = -EINVAL;
 514                 break;
 515         }
 516         mutex_unlock(&reboot_mutex);
 517         return ret;
 518 }
 519
 520 static void deferred_cad(struct work_struct *dummy)
 521 {
 522         kernel_restart(NULL);
 523 }
 524
 525 /*
 526  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 527  * As it's called within an interrupt, it may NOT sync: the only choice
 528  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 529  */
 530 void ctrl_alt_del(void)
 531 {
 532         static DECLARE_WORK(cad_work, deferred_cad);
 533
 534         if (C_A_D)
 535                 schedule_work(&cad_work);
 536         else
 537                 kill_cad_pid(SIGINT, 1);
 538 }
 539
 540 /*
 541  * Unprivileged users may change the real gid to the effective gid
 542  * or vice versa.  (BSD-style)
 543  *
 544  * If you set the real gid at all, or set the effective gid to a value not
 545  * equal to the real gid, then the saved gid is set to the new effective gid.
 546  *
 547  * This makes it possible for a setgid program to completely drop its
 548  * privileges, which is often a useful assertion to make when you are doing
 549  * a security audit over a program.
 550  *
 551  * The general idea is that a program which uses just setregid() will be
 552  * 100% compatible with BSD.  A program which uses just setgid() will be
 553  * 100% compatible with POSIX with saved IDs.
 554  *
 555  * SMP: There are not races, the GIDs are checked only by filesystem
 556  *      operations (as far as semantic preservation is concerned).
 557  */
 558 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 559 {
 560         struct user_namespace *ns = current_user_ns();
 561         const struct cred *old;
 562         struct cred *new;
 563         int retval;
 564         kgid_t krgid, kegid;
 565
 566         krgid = make_kgid(ns, rgid);
 567         kegid = make_kgid(ns, egid);
 568
 569         if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 570                 return -EINVAL;
 571         if ((egid != (gid_t) -1) && !gid_valid(kegid))
 572                 return -EINVAL;
 573
 574         new = prepare_creds();
 575         if (!new)
 576                 return -ENOMEM;
 577         old = current_cred();
 578
 579         retval = -EPERM;
 580         if (rgid != (gid_t) -1) {
 581                 if (gid_eq(old->gid, krgid) ||
 582                     gid_eq(old->egid, krgid) ||
 583                     nsown_capable(CAP_SETGID))
 584                         new->gid = krgid;
 585                 else
 586                         goto error;
 587         }
 588         if (egid != (gid_t) -1) {
 589                 if (gid_eq(old->gid, kegid) ||
 590                     gid_eq(old->egid, kegid) ||
 591                     gid_eq(old->sgid, kegid) ||
 592                     nsown_capable(CAP_SETGID))
 593                         new->egid = kegid;
 594                 else
 595                         goto error;
 596         }
 597
 598         if (rgid != (gid_t) -1 ||
 599             (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
 600                 new->sgid = new->egid;
 601         new->fsgid = new->egid;
 602
 603         return commit_creds(new);
 604
 605 error:
 606         abort_creds(new);
 607         return retval;
 608 }
 609
 610 /*
 611  * setgid() is implemented like SysV w/ SAVED_IDS
 612  *
 613  * SMP: Same implicit races as above.
 614  */
 615 SYSCALL_DEFINE1(setgid, gid_t, gid)
 616 {
 617         struct user_namespace *ns = current_user_ns();
 618         const struct cred *old;
 619         struct cred *new;
 620         int retval;
 621         kgid_t kgid;
 622
 623         kgid = make_kgid(ns, gid);
 624         if (!gid_valid(kgid))
 625                 return -EINVAL;
 626
 627         new = prepare_creds();
 628         if (!new)
 629                 return -ENOMEM;
 630         old = current_cred();
 631
 632         retval = -EPERM;
 633         if (nsown_capable(CAP_SETGID))
 634                 new->gid = new->egid = new->sgid = new->fsgid = kgid;
 635         else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
 636                 new->egid = new->fsgid = kgid;
 637         else
 638                 goto error;
 639
 640         return commit_creds(new);
 641
 642 error:
 643         abort_creds(new);
 644         return retval;
 645 }
 646
 647 /*
 648  * change the user struct in a credentials set to match the new UID
 649  */
 650 static int set_user(struct cred *new)
 651 {
 652         struct user_struct *new_user;
 653
 654         new_user = alloc_uid(new->uid);
 655         if (!new_user)
 656                 return -EAGAIN;
 657
 658         /*
 659          * We don't fail in case of NPROC limit excess here because too many
 660          * poorly written programs don't check set*uid() return code, assuming
 661          * it never fails if called by root.  We may still enforce NPROC limit
 662          * for programs doing set*uid()+execve() by harmlessly deferring the
 663          * failure to the execve() stage.
 664          */
 665         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
 666                         new_user != INIT_USER)
 667                 current->flags |= PF_NPROC_EXCEEDED;
 668         else
 669                 current->flags &= ~PF_NPROC_EXCEEDED;
 670
 671         free_uid(new->user);
 672         new->user = new_user;
 673         return 0;
 674 }
 675
 676 /*
 677  * Unprivileged users may change the real uid to the effective uid
 678  * or vice versa.  (BSD-style)
 679  *
 680  * If you set the real uid at all, or set the effective uid to a value not
 681  * equal to the real uid, then the saved uid is set to the new effective uid.
 682  *
 683  * This makes it possible for a setuid program to completely drop its
 684  * privileges, which is often a useful assertion to make when you are doing
 685  * a security audit over a program.
 686  *
 687  * The general idea is that a program which uses just setreuid() will be
 688  * 100% compatible with BSD.  A program which uses just setuid() will be
 689  * 100% compatible with POSIX with saved IDs.
 690  */
 691 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 692 {
 693         struct user_namespace *ns = current_user_ns();
 694         const struct cred *old;
 695         struct cred *new;
 696         int retval;
 697         kuid_t kruid, keuid;
 698
 699         kruid = make_kuid(ns, ruid);
 700         keuid = make_kuid(ns, euid);
 701
 702         if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 703                 return -EINVAL;
 704         if ((euid != (uid_t) -1) && !uid_valid(keuid))
 705                 return -EINVAL;
 706
 707         new = prepare_creds();
 708         if (!new)
 709                 return -ENOMEM;
 710         old = current_cred();
 711
 712         retval = -EPERM;
 713         if (ruid != (uid_t) -1) {
 714                 new->uid = kruid;
 715                 if (!uid_eq(old->uid, kruid) &&
 716                     !uid_eq(old->euid, kruid) &&
 717                     !nsown_capable(CAP_SETUID))
 718                         goto error;
 719         }
 720
 721         if (euid != (uid_t) -1) {
 722                 new->euid = keuid;
 723                 if (!uid_eq(old->uid, keuid) &&
 724                     !uid_eq(old->euid, keuid) &&
 725                     !uid_eq(old->suid, keuid) &&
 726                     !nsown_capable(CAP_SETUID))
 727                         goto error;
 728         }
 729
 730         if (!uid_eq(new->uid, old->uid)) {
 731                 retval = set_user(new);
 732                 if (retval < 0)
 733                         goto error;
 734         }
 735         if (ruid != (uid_t) -1 ||
 736             (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
 737                 new->suid = new->euid;
 738         new->fsuid = new->euid;
 739
 740         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 741         if (retval < 0)
 742                 goto error;
 743
 744         return commit_creds(new);
 745
 746 error:
 747         abort_creds(new);
 748         return retval;
 749 }
 750
 751 /*
 752  * setuid() is implemented like SysV with SAVED_IDS
 753  *
 754  * Note that SAVED_ID's is deficient in that a setuid root program
 755  * like sendmail, for example, cannot set its uid to be a normal
 756  * user and then switch back, because if you're root, setuid() sets
 757  * the saved uid too.  If you don't like this, blame the bright people
 758  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 759  * will allow a root program to temporarily drop privileges and be able to
 760  * regain them by swapping the real and effective uid.
 761  */
 762 SYSCALL_DEFINE1(setuid, uid_t, uid)
 763 {
 764         struct user_namespace *ns = current_user_ns();
 765         const struct cred *old;
 766         struct cred *new;
 767         int retval;
 768         kuid_t kuid;
 769
 770         kuid = make_kuid(ns, uid);
 771         if (!uid_valid(kuid))
 772                 return -EINVAL;
 773
 774         new = prepare_creds();
 775         if (!new)
 776                 return -ENOMEM;
 777         old = current_cred();
 778
 779         retval = -EPERM;
 780         if (nsown_capable(CAP_SETUID)) {
 781                 new->suid = new->uid = kuid;
 782                 if (!uid_eq(kuid, old->uid)) {
 783                         retval = set_user(new);
 784                         if (retval < 0)
 785                                 goto error;
 786                 }
 787         } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
 788                 goto error;
 789         }
 790
 791         new->fsuid = new->euid = kuid;
 792
 793         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 794         if (retval < 0)
 795                 goto error;
 796
 797         return commit_creds(new);
 798
 799 error:
 800         abort_creds(new);
 801         return retval;
 802 }
 803
 804
 805 /*
 806  * This function implements a generic ability to update ruid, euid,
 807  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 808  */
 809 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 810 {
 811         struct user_namespace *ns = current_user_ns();
 812         const struct cred *old;
 813         struct cred *new;
 814         int retval;
 815         kuid_t kruid, keuid, ksuid;
 816
 817         kruid = make_kuid(ns, ruid);
 818         keuid = make_kuid(ns, euid);
 819         ksuid = make_kuid(ns, suid);
 820
 821         if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 822                 return -EINVAL;
 823
 824         if ((euid != (uid_t) -1) && !uid_valid(keuid))
 825                 return -EINVAL;
 826
 827         if ((suid != (uid_t) -1) && !uid_valid(ksuid))
 828                 return -EINVAL;
 829
 830         new = prepare_creds();
 831         if (!new)
 832                 return -ENOMEM;
 833
 834         old = current_cred();
 835
 836         retval = -EPERM;
 837         if (!nsown_capable(CAP_SETUID)) {
 838                 if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
 839                     !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
 840                         goto error;
 841                 if (euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
 842                     !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
 843                         goto error;
 844                 if (suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
 845                     !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
 846                         goto error;
 847         }
 848
 849         if (ruid != (uid_t) -1) {
 850                 new->uid = kruid;
 851                 if (!uid_eq(kruid, old->uid)) {
 852                         retval = set_user(new);
 853                         if (retval < 0)
 854                                 goto error;
 855                 }
 856         }
 857         if (euid != (uid_t) -1)
 858                 new->euid = keuid;
 859         if (suid != (uid_t) -1)
 860                 new->suid = ksuid;
 861         new->fsuid = new->euid;
 862
 863         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 864         if (retval < 0)
 865                 goto error;
 866
 867         return commit_creds(new);
 868
 869 error:
 870         abort_creds(new);
 871         return retval;
 872 }
 873
 874 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
 875 {
 876         const struct cred *cred = current_cred();
 877         int retval;
 878         uid_t ruid, euid, suid;
 879
 880         ruid = from_kuid_munged(cred->user_ns, cred->uid);
 881         euid = from_kuid_munged(cred->user_ns, cred->euid);
 882         suid = from_kuid_munged(cred->user_ns, cred->suid);
 883
 884         if (!(retval   = put_user(ruid, ruidp)) &&
 885             !(retval   = put_user(euid, euidp)))
 886                 retval = put_user(suid, suidp);
 887
 888         return retval;
 889 }
 890
 891 /*
 892  * Same as above, but for rgid, egid, sgid.
 893  */
 894 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 895 {
 896         struct user_namespace *ns = current_user_ns();
 897         const struct cred *old;
 898         struct cred *new;
 899         int retval;
 900         kgid_t krgid, kegid, ksgid;
 901
 902         krgid = make_kgid(ns, rgid);
 903         kegid = make_kgid(ns, egid);
 904         ksgid = make_kgid(ns, sgid);
 905
 906         if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 907                 return -EINVAL;
 908         if ((egid != (gid_t) -1) && !gid_valid(kegid))
 909                 return -EINVAL;
 910         if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
 911                 return -EINVAL;
 912
 913         new = prepare_creds();
 914         if (!new)
 915                 return -ENOMEM;
 916         old = current_cred();
 917
 918         retval = -EPERM;
 919         if (!nsown_capable(CAP_SETGID)) {
 920                 if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
 921                     !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
 922                         goto error;
 923                 if (egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
 924                     !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
 925                         goto error;
 926                 if (sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
 927                     !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
 928                         goto error;
 929         }
 930
 931         if (rgid != (gid_t) -1)
 932                 new->gid = krgid;
 933         if (egid != (gid_t) -1)
 934                 new->egid = kegid;
 935         if (sgid != (gid_t) -1)
 936                 new->sgid = ksgid;
 937         new->fsgid = new->egid;
 938
 939         return commit_creds(new);
 940
 941 error:
 942         abort_creds(new);
 943         return retval;
 944 }
 945
 946 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
 947 {
 948         const struct cred *cred = current_cred();
 949         int retval;
 950         gid_t rgid, egid, sgid;
 951
 952         rgid = from_kgid_munged(cred->user_ns, cred->gid);
 953         egid = from_kgid_munged(cred->user_ns, cred->egid);
 954         sgid = from_kgid_munged(cred->user_ns, cred->sgid);
 955
 956         if (!(retval   = put_user(rgid, rgidp)) &&
 957             !(retval   = put_user(egid, egidp)))
 958                 retval = put_user(sgid, sgidp);
 959
 960         return retval;
 961 }
 962
 963
 964 /*
 965  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 966  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 967  * whatever uid it wants to). It normally shadows "euid", except when
 968  * explicitly set by setfsuid() or for access..
 969  */
 970 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 971 {
 972         const struct cred *old;
 973         struct cred *new;
 974         uid_t old_fsuid;
 975         kuid_t kuid;
 976
 977         old = current_cred();
 978         old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
 979
 980         kuid = make_kuid(old->user_ns, uid);
 981         if (!uid_valid(kuid))
 982                 return old_fsuid;
 983
 984         new = prepare_creds();
 985         if (!new)
 986                 return old_fsuid;
 987
 988         if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
 989             uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
 990             nsown_capable(CAP_SETUID)) {
 991                 if (!uid_eq(kuid, old->fsuid)) {
 992                         new->fsuid = kuid;
 993                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 994                                 goto change_okay;
 995                 }
 996         }
 997
 998         abort_creds(new);
 999         return old_fsuid;
1000
1001 change_okay:
1002         commit_creds(new);
1003         return old_fsuid;
1004 }
1005
1006 /*
1007  * Samma på svenska..
1008  */
1009 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
1010 {
1011         const struct cred *old;
1012         struct cred *new;
1013         gid_t old_fsgid;
1014         kgid_t kgid;
1015
1016         old = current_cred();
1017         old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
1018
1019         kgid = make_kgid(old->user_ns, gid);
1020         if (!gid_valid(kgid))
1021                 return old_fsgid;
1022
1023         new = prepare_creds();
1024         if (!new)
1025                 return old_fsgid;
1026
1027         if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
1028             gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
1029             nsown_capable(CAP_SETGID)) {
1030                 if (!gid_eq(kgid, old->fsgid)) {
1031                         new->fsgid = kgid;
1032                         goto change_okay;
1033                 }
1034         }
1035
1036         abort_creds(new);
1037         return old_fsgid;
1038
1039 change_okay:
1040         commit_creds(new);
1041         return old_fsgid;
1042 }
1043
1044 void do_sys_times(struct tms *tms)
1045 {
1046         cputime_t tgutime, tgstime, cutime, cstime;
1047
1048         spin_lock_irq(&current->sighand->siglock);
1049         thread_group_cputime_adjusted(current, &tgutime, &tgstime);
1050         cutime = current->signal->cutime;
1051         cstime = current->signal->cstime;
1052         spin_unlock_irq(&current->sighand->siglock);
1053         tms->tms_utime = cputime_to_clock_t(tgutime);
1054         tms->tms_stime = cputime_to_clock_t(tgstime);
1055         tms->tms_cutime = cputime_to_clock_t(cutime);
1056         tms->tms_cstime = cputime_to_clock_t(cstime);
1057 }
1058
1059 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
1060 {
1061         if (tbuf) {
1062                 struct tms tmp;
1063
1064                 do_sys_times(&tmp);
1065                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1066                         return -EFAULT;
1067         }
1068         force_successful_syscall_return();
1069         return (long) jiffies_64_to_clock_t(get_jiffies_64());
1070 }
1071
1072 /*
1073  * This needs some heavy checking ...
1074  * I just haven't the stomach for it. I also don't fully
1075  * understand sessions/pgrp etc. Let somebody who does explain it.
1076  *
1077  * OK, I think I have the protection semantics right.... this is really
1078  * only important on a multi-user system anyway, to make sure one user
1079  * can't send a signal to a process owned by another.  -TYT, 12/12/91
1080  *
1081  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1082  * LBT 04.03.94
1083  */
1084 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1085 {
1086         struct task_struct *p;
1087         struct task_struct *group_leader = current->group_leader;
1088         struct pid *pgrp;
1089         int err;
1090
1091         if (!pid)
1092                 pid = task_pid_vnr(group_leader);
1093         if (!pgid)
1094                 pgid = pid;
1095         if (pgid < 0)
1096                 return -EINVAL;
1097         rcu_read_lock();
1098
1099         /* From this point forward we keep holding onto the tasklist lock
1100          * so that our parent does not change from under us. -DaveM
1101          */
1102         write_lock_irq(&tasklist_lock);
1103
1104         err = -ESRCH;
1105         p = find_task_by_vpid(pid);
1106         if (!p)
1107                 goto out;
1108
1109         err = -EINVAL;
1110         if (!thread_group_leader(p))
1111                 goto out;
1112
1113         if (same_thread_group(p->real_parent, group_leader)) {
1114                 err = -EPERM;
1115                 if (task_session(p) != task_session(group_leader))
1116                         goto out;
1117                 err = -EACCES;
1118                 if (p->did_exec)
1119                         goto out;
1120         } else {
1121                 err = -ESRCH;
1122                 if (p != group_leader)
1123                         goto out;
1124         }
1125
1126         err = -EPERM;
1127         if (p->signal->leader)
1128                 goto out;
1129
1130         pgrp = task_pid(p);
1131         if (pgid != pid) {
1132                 struct task_struct *g;
1133
1134                 pgrp = find_vpid(pgid);
1135                 g = pid_task(pgrp, PIDTYPE_PGID);
1136                 if (!g || task_session(g) != task_session(group_leader))
1137                         goto out;
1138         }
1139
1140         err = security_task_setpgid(p, pgid);
1141         if (err)
1142                 goto out;
1143
1144         if (task_pgrp(p) != pgrp)
1145                 change_pid(p, PIDTYPE_PGID, pgrp);
1146
1147         err = 0;
1148 out:
1149         /* All paths lead to here, thus we are safe. -DaveM */
1150         write_unlock_irq(&tasklist_lock);
1151         rcu_read_unlock();
1152         return err;
1153 }
1154
1155 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1156 {
1157         struct task_struct *p;
1158         struct pid *grp;
1159         int retval;
1160
1161         rcu_read_lock();
1162         if (!pid)
1163                 grp = task_pgrp(current);
1164         else {
1165                 retval = -ESRCH;
1166                 p = find_task_by_vpid(pid);
1167                 if (!p)
1168                         goto out;
1169                 grp = task_pgrp(p);
1170                 if (!grp)
1171                         goto out;
1172
1173                 retval = security_task_getpgid(p);
1174                 if (retval)
1175                         goto out;
1176         }
1177         retval = pid_vnr(grp);
1178 out:
1179         rcu_read_unlock();
1180         return retval;
1181 }
1182
1183 #ifdef __ARCH_WANT_SYS_GETPGRP
1184
1185 SYSCALL_DEFINE0(getpgrp)
1186 {
1187         return sys_getpgid(0);
1188 }
1189
1190 #endif
1191
1192 SYSCALL_DEFINE1(getsid, pid_t, pid)
1193 {
1194         struct task_struct *p;
1195         struct pid *sid;
1196         int retval;
1197
1198         rcu_read_lock();
1199         if (!pid)
1200                 sid = task_session(current);
1201         else {
1202                 retval = -ESRCH;
1203                 p = find_task_by_vpid(pid);
1204                 if (!p)
1205                         goto out;
1206                 sid = task_session(p);
1207                 if (!sid)
1208                         goto out;
1209
1210                 retval = security_task_getsid(p);
1211                 if (retval)
1212                         goto out;
1213         }
1214         retval = pid_vnr(sid);
1215 out:
1216         rcu_read_unlock();
1217         return retval;
1218 }
1219
1220 SYSCALL_DEFINE0(setsid)
1221 {
1222         struct task_struct *group_leader = current->group_leader;
1223         struct pid *sid = task_pid(group_leader);
1224         pid_t session = pid_vnr(sid);
1225         int err = -EPERM;
1226
1227         write_lock_irq(&tasklist_lock);
1228         /* Fail if I am already a session leader */
1229         if (group_leader->signal->leader)
1230                 goto out;
1231
1232         /* Fail if a process group id already exists that equals the
1233          * proposed session id.
1234          */
1235         if (pid_task(sid, PIDTYPE_PGID))
1236                 goto out;
1237
1238         group_leader->signal->leader = 1;
1239         __set_special_pids(sid);
1240
1241         proc_clear_tty(group_leader);
1242
1243         err = session;
1244 out:
1245         write_unlock_irq(&tasklist_lock);
1246         if (err > 0) {
1247                 proc_sid_connector(group_leader);
1248                 sched_autogroup_create_attach(group_leader);
1249         }
1250         return err;
1251 }
1252
1253 DECLARE_RWSEM(uts_sem);
1254
1255 #ifdef COMPAT_UTS_MACHINE
1256 #define override_architecture(name) \
1257         (personality(current->personality) == PER_LINUX32 && \
1258          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1259                       sizeof(COMPAT_UTS_MACHINE)))
1260 #else
1261 #define override_architecture(name)     0
1262 #endif
1263
1264 /*
1265  * Work around broken programs that cannot handle "Linux 3.0".
1266  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1267  */
1268 static int override_release(char __user *release, size_t len)
1269 {
1270         int ret = 0;
1271
1272         if (current->personality & UNAME26) {
1273                 const char *rest = UTS_RELEASE;
1274                 char buf[65] = { 0 };
1275                 int ndots = 0;
1276                 unsigned v;
1277                 size_t copy;
1278
1279                 while (*rest) {
1280                         if (*rest == '.' && ++ndots >= 3)
1281                                 break;
1282                         if (!isdigit(*rest) && *rest != '.')
1283                                 break;
1284                         rest++;
1285                 }
1286                 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
1287                 copy = clamp_t(size_t, len, 1, sizeof(buf));
1288                 copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
1289                 ret = copy_to_user(release, buf, copy + 1);
1290         }
1291         return ret;
1292 }
1293
1294 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1295 {
1296         int errno = 0;
1297
1298         down_read(&uts_sem);
1299         if (copy_to_user(name, utsname(), sizeof *name))
1300                 errno = -EFAULT;
1301         up_read(&uts_sem);
1302
1303         if (!errno && override_release(name->release, sizeof(name->release)))
1304                 errno = -EFAULT;
1305         if (!errno && override_architecture(name))
1306                 errno = -EFAULT;
1307         return errno;
1308 }
1309
1310 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1311 /*
1312  * Old cruft
1313  */
1314 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1315 {
1316         int error = 0;
1317
1318         if (!name)
1319                 return -EFAULT;
1320
1321         down_read(&uts_sem);
1322         if (copy_to_user(name, utsname(), sizeof(*name)))
1323                 error = -EFAULT;
1324         up_read(&uts_sem);
1325
1326         if (!error && override_release(name->release, sizeof(name->release)))
1327                 error = -EFAULT;
1328         if (!error && override_architecture(name))
1329                 error = -EFAULT;
1330         return error;
1331 }
1332
1333 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1334 {
1335         int error;
1336
1337         if (!name)
1338                 return -EFAULT;
1339         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1340                 return -EFAULT;
1341
1342         down_read(&uts_sem);
1343         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1344                                __OLD_UTS_LEN);
1345         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1346         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1347                                 __OLD_UTS_LEN);
1348         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1349         error |= __copy_to_user(&name->release, &utsname()->release,
1350                                 __OLD_UTS_LEN);
1351         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1352         error |= __copy_to_user(&name->version, &utsname()->version,
1353                                 __OLD_UTS_LEN);
1354         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1355         error |= __copy_to_user(&name->machine, &utsname()->machine,
1356                                 __OLD_UTS_LEN);
1357         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1358         up_read(&uts_sem);
1359
1360         if (!error && override_architecture(name))
1361                 error = -EFAULT;
1362         if (!error && override_release(name->release, sizeof(name->release)))
1363                 error = -EFAULT;
1364         return error ? -EFAULT : 0;
1365 }
1366 #endif
1367
1368 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1369 {
1370         int errno;
1371         char tmp[__NEW_UTS_LEN];
1372
1373         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1374                 return -EPERM;
1375
1376         if (len < 0 || len > __NEW_UTS_LEN)
1377                 return -EINVAL;
1378         down_write(&uts_sem);
1379         errno = -EFAULT;
1380         if (!copy_from_user(tmp, name, len)) {
1381                 struct new_utsname *u = utsname();
1382
1383                 memcpy(u->nodename, tmp, len);
1384                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1385                 errno = 0;
1386                 uts_proc_notify(UTS_PROC_HOSTNAME);
1387         }
1388         up_write(&uts_sem);
1389         return errno;
1390 }
1391
1392 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1393
1394 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1395 {
1396         int i, errno;
1397         struct new_utsname *u;
1398
1399         if (len < 0)
1400                 return -EINVAL;
1401         down_read(&uts_sem);
1402         u = utsname();
1403         i = 1 + strlen(u->nodename);
1404         if (i > len)
1405                 i = len;
1406         errno = 0;
1407         if (copy_to_user(name, u->nodename, i))
1408                 errno = -EFAULT;
1409         up_read(&uts_sem);
1410         return errno;
1411 }
1412
1413 #endif
1414
1415 /*
1416  * Only setdomainname; getdomainname can be implemented by calling
1417  * uname()
1418  */
1419 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1420 {
1421         int errno;
1422         char tmp[__NEW_UTS_LEN];
1423
1424         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1425                 return -EPERM;
1426         if (len < 0 || len > __NEW_UTS_LEN)
1427                 return -EINVAL;
1428
1429         down_write(&uts_sem);
1430         errno = -EFAULT;
1431         if (!copy_from_user(tmp, name, len)) {
1432                 struct new_utsname *u = utsname();
1433
1434                 memcpy(u->domainname, tmp, len);
1435                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1436                 errno = 0;
1437                 uts_proc_notify(UTS_PROC_DOMAINNAME);
1438         }
1439         up_write(&uts_sem);
1440         return errno;
1441 }
1442
1443 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1444 {
1445         struct rlimit value;
1446         int ret;
1447
1448         ret = do_prlimit(current, resource, NULL, &value);
1449         if (!ret)
1450                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1451
1452         return ret;
1453 }
1454
1455 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1456
1457 /*
1458  *      Back compatibility for getrlimit. Needed for some apps.
1459  */
1460
1461 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1462                 struct rlimit __user *, rlim)
1463 {
1464         struct rlimit x;
1465         if (resource >= RLIM_NLIMITS)
1466                 return -EINVAL;
1467
1468         task_lock(current->group_leader);
1469         x = current->signal->rlim[resource];
1470         task_unlock(current->group_leader);
1471         if (x.rlim_cur > 0x7FFFFFFF)
1472                 x.rlim_cur = 0x7FFFFFFF;
1473         if (x.rlim_max > 0x7FFFFFFF)
1474                 x.rlim_max = 0x7FFFFFFF;
1475         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1476 }
1477
1478 #endif
1479
1480 static inline bool rlim64_is_infinity(__u64 rlim64)
1481 {
1482 #if BITS_PER_LONG < 64
1483         return rlim64 >= ULONG_MAX;
1484 #else
1485         return rlim64 == RLIM64_INFINITY;
1486 #endif
1487 }
1488
1489 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1490 {
1491         if (rlim->rlim_cur == RLIM_INFINITY)
1492                 rlim64->rlim_cur = RLIM64_INFINITY;
1493         else
1494                 rlim64->rlim_cur = rlim->rlim_cur;
1495         if (rlim->rlim_max == RLIM_INFINITY)
1496                 rlim64->rlim_max = RLIM64_INFINITY;
1497         else
1498                 rlim64->rlim_max = rlim->rlim_max;
1499 }
1500
1501 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1502 {
1503         if (rlim64_is_infinity(rlim64->rlim_cur))
1504                 rlim->rlim_cur = RLIM_INFINITY;
1505         else
1506                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1507         if (rlim64_is_infinity(rlim64->rlim_max))
1508                 rlim->rlim_max = RLIM_INFINITY;
1509         else
1510                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1511 }
1512
1513 /* make sure you are allowed to change @tsk limits before calling this */
1514 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1515                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1516 {
1517         struct rlimit *rlim;
1518         int retval = 0;
1519
1520         if (resource >= RLIM_NLIMITS)
1521                 return -EINVAL;
1522         if (new_rlim) {
1523                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1524                         return -EINVAL;
1525                 if (resource == RLIMIT_NOFILE &&
1526                                 new_rlim->rlim_max > sysctl_nr_open)
1527                         return -EPERM;
1528         }
1529
1530         /* protect tsk->signal and tsk->sighand from disappearing */
1531         read_lock(&tasklist_lock);
1532         if (!tsk->sighand) {
1533                 retval = -ESRCH;
1534                 goto out;
1535         }
1536
1537         rlim = tsk->signal->rlim + resource;
1538         task_lock(tsk->group_leader);
1539         if (new_rlim) {
1540                 /* Keep the capable check against init_user_ns until
1541                    cgroups can contain all limits */
1542                 if (new_rlim->rlim_max > rlim->rlim_max &&
1543                                 !capable(CAP_SYS_RESOURCE))
1544                         retval = -EPERM;
1545                 if (!retval)
1546                         retval = security_task_setrlimit(tsk->group_leader,
1547                                         resource, new_rlim);
1548                 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1549                         /*
1550                          * The caller is asking for an immediate RLIMIT_CPU
1551                          * expiry.  But we use the zero value to mean "it was
1552                          * never set".  So let's cheat and make it one second
1553                          * instead
1554                          */
1555                         new_rlim->rlim_cur = 1;
1556                 }
1557         }
1558         if (!retval) {
1559                 if (old_rlim)
1560                         *old_rlim = *rlim;
1561                 if (new_rlim)
1562                         *rlim = *new_rlim;
1563         }
1564         task_unlock(tsk->group_leader);
1565
1566         /*
1567          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1568          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1569          * very long-standing error, and fixing it now risks breakage of
1570          * applications, so we live with it
1571          */
1572          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1573                          new_rlim->rlim_cur != RLIM_INFINITY)
1574                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1575 out:
1576         read_unlock(&tasklist_lock);
1577         return retval;
1578 }
1579
1580 /* rcu lock must be held */
1581 static int check_prlimit_permission(struct task_struct *task)
1582 {
1583         const struct cred *cred = current_cred(), *tcred;
1584
1585         if (current == task)
1586                 return 0;
1587
1588         tcred = __task_cred(task);
1589         if (uid_eq(cred->uid, tcred->euid) &&
1590             uid_eq(cred->uid, tcred->suid) &&
1591             uid_eq(cred->uid, tcred->uid)  &&
1592             gid_eq(cred->gid, tcred->egid) &&
1593             gid_eq(cred->gid, tcred->sgid) &&
1594             gid_eq(cred->gid, tcred->gid))
1595                 return 0;
1596         if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1597                 return 0;
1598
1599         return -EPERM;
1600 }
1601
1602 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1603                 const struct rlimit64 __user *, new_rlim,
1604                 struct rlimit64 __user *, old_rlim)
1605 {
1606         struct rlimit64 old64, new64;
1607         struct rlimit old, new;
1608         struct task_struct *tsk;
1609         int ret;
1610
1611         if (new_rlim) {
1612                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1613                         return -EFAULT;
1614                 rlim64_to_rlim(&new64, &new);
1615         }
1616
1617         rcu_read_lock();
1618         tsk = pid ? find_task_by_vpid(pid) : current;
1619         if (!tsk) {
1620                 rcu_read_unlock();
1621                 return -ESRCH;
1622         }
1623         ret = check_prlimit_permission(tsk);
1624         if (ret) {
1625                 rcu_read_unlock();
1626                 return ret;
1627         }
1628         get_task_struct(tsk);
1629         rcu_read_unlock();
1630
1631         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1632                         old_rlim ? &old : NULL);
1633
1634         if (!ret && old_rlim) {
1635                 rlim_to_rlim64(&old, &old64);
1636                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1637                         ret = -EFAULT;
1638         }
1639
1640         put_task_struct(tsk);
1641         return ret;
1642 }
1643
1644 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1645 {
1646         struct rlimit new_rlim;
1647
1648         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1649                 return -EFAULT;
1650         return do_prlimit(current, resource, &new_rlim, NULL);
1651 }
1652
1653 /*
1654  * It would make sense to put struct rusage in the task_struct,
1655  * except that would make the task_struct be *really big*.  After
1656  * task_struct gets moved into malloc'ed memory, it would
1657  * make sense to do this.  It will make moving the rest of the information
1658  * a lot simpler!  (Which we're not doing right now because we're not
1659  * measuring them yet).
1660  *
1661  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1662  * races with threads incrementing their own counters.  But since word
1663  * reads are atomic, we either get new values or old values and we don't
1664  * care which for the sums.  We always take the siglock to protect reading
1665  * the c* fields from p->signal from races with exit.c updating those
1666  * fields when reaping, so a sample either gets all the additions of a
1667  * given child after it's reaped, or none so this sample is before reaping.
1668  *
1669  * Locking:
1670  * We need to take the siglock for CHILDEREN, SELF and BOTH
1671  * for  the cases current multithreaded, non-current single threaded
1672  * non-current multithreaded.  Thread traversal is now safe with
1673  * the siglock held.
1674  * Strictly speaking, we donot need to take the siglock if we are current and
1675  * single threaded,  as no one else can take our signal_struct away, no one
1676  * else can  reap the  children to update signal->c* counters, and no one else
1677  * can race with the signal-> fields. If we do not take any lock, the
1678  * signal-> fields could be read out of order while another thread was just
1679  * exiting. So we should  place a read memory barrier when we avoid the lock.
1680  * On the writer side,  write memory barrier is implied in  __exit_signal
1681  * as __exit_signal releases  the siglock spinlock after updating the signal->
1682  * fields. But we don't do this yet to keep things simple.
1683  *
1684  */
1685
1686 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1687 {
1688         r->ru_nvcsw += t->nvcsw;
1689         r->ru_nivcsw += t->nivcsw;
1690         r->ru_minflt += t->min_flt;
1691         r->ru_majflt += t->maj_flt;
1692         r->ru_inblock += task_io_get_inblock(t);
1693         r->ru_oublock += task_io_get_oublock(t);
1694 }
1695
1696 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1697 {
1698         struct task_struct *t;
1699         unsigned long flags;
1700         cputime_t tgutime, tgstime, utime, stime;
1701         unsigned long maxrss = 0;
1702
1703         memset((char *) r, 0, sizeof *r);
1704         utime = stime = 0;
1705
1706         if (who == RUSAGE_THREAD) {
1707                 task_cputime_adjusted(current, &utime, &stime);
1708                 accumulate_thread_rusage(p, r);
1709                 maxrss = p->signal->maxrss;
1710                 goto out;
1711         }
1712
1713         if (!lock_task_sighand(p, &flags))
1714                 return;
1715
1716         switch (who) {
1717                 case RUSAGE_BOTH:
1718                 case RUSAGE_CHILDREN:
1719                         utime = p->signal->cutime;
1720                         stime = p->signal->cstime;
1721                         r->ru_nvcsw = p->signal->cnvcsw;
1722                         r->ru_nivcsw = p->signal->cnivcsw;
1723                         r->ru_minflt = p->signal->cmin_flt;
1724                         r->ru_majflt = p->signal->cmaj_flt;
1725                         r->ru_inblock = p->signal->cinblock;
1726                         r->ru_oublock = p->signal->coublock;
1727                         maxrss = p->signal->cmaxrss;
1728
1729                         if (who == RUSAGE_CHILDREN)
1730                                 break;
1731
1732                 case RUSAGE_SELF:
1733                         thread_group_cputime_adjusted(p, &tgutime, &tgstime);
1734                         utime += tgutime;
1735                         stime += tgstime;
1736                         r->ru_nvcsw += p->signal->nvcsw;
1737                         r->ru_nivcsw += p->signal->nivcsw;
1738                         r->ru_minflt += p->signal->min_flt;
1739                         r->ru_majflt += p->signal->maj_flt;
1740                         r->ru_inblock += p->signal->inblock;
1741                         r->ru_oublock += p->signal->oublock;
1742                         if (maxrss < p->signal->maxrss)
1743                                 maxrss = p->signal->maxrss;
1744                         t = p;
1745                         do {
1746                                 accumulate_thread_rusage(t, r);
1747                                 t = next_thread(t);
1748                         } while (t != p);
1749                         break;
1750
1751                 default:
1752                         BUG();
1753         }
1754         unlock_task_sighand(p, &flags);
1755
1756 out:
1757         cputime_to_timeval(utime, &r->ru_utime);
1758         cputime_to_timeval(stime, &r->ru_stime);
1759
1760         if (who != RUSAGE_CHILDREN) {
1761                 struct mm_struct *mm = get_task_mm(p);
1762                 if (mm) {
1763                         setmax_mm_hiwater_rss(&maxrss, mm);
1764                         mmput(mm);
1765                 }
1766         }
1767         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1768 }
1769
1770 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1771 {
1772         struct rusage r;
1773         k_getrusage(p, who, &r);
1774         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1775 }
1776
1777 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1778 {
1779         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1780             who != RUSAGE_THREAD)
1781                 return -EINVAL;
1782         return getrusage(current, who, ru);
1783 }
1784
1785 SYSCALL_DEFINE1(umask, int, mask)
1786 {
1787         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1788         return mask;
1789 }
1790
1791 #ifdef CONFIG_CHECKPOINT_RESTORE
1792 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1793 {
1794         struct fd exe;
1795         struct dentry *dentry;
1796         int err;
1797
1798         exe = fdget(fd);
1799         if (!exe.file)
1800                 return -EBADF;
1801
1802         dentry = exe.file->f_path.dentry;
1803
1804         /*
1805          * Because the original mm->exe_file points to executable file, make
1806          * sure that this one is executable as well, to avoid breaking an
1807          * overall picture.
1808          */
1809         err = -EACCES;
1810         if (!S_ISREG(dentry->d_inode->i_mode)   ||
1811             exe.file->f_path.mnt->mnt_flags & MNT_NOEXEC)
1812                 goto exit;
1813
1814         err = inode_permission(dentry->d_inode, MAY_EXEC);
1815         if (err)
1816                 goto exit;
1817
1818         down_write(&mm->mmap_sem);
1819
1820         /*
1821          * Forbid mm->exe_file change if old file still mapped.
1822          */
1823         err = -EBUSY;
1824         if (mm->exe_file) {
1825                 struct vm_area_struct *vma;
1826
1827                 for (vma = mm->mmap; vma; vma = vma->vm_next)
1828                         if (vma->vm_file &&
1829                             path_equal(&vma->vm_file->f_path,
1830                                        &mm->exe_file->f_path))
1831                                 goto exit_unlock;
1832         }
1833
1834         /*
1835          * The symlink can be changed only once, just to disallow arbitrary
1836          * transitions malicious software might bring in. This means one
1837          * could make a snapshot over all processes running and monitor
1838          * /proc/pid/exe changes to notice unusual activity if needed.
1839          */
1840         err = -EPERM;
1841         if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags))
1842                 goto exit_unlock;
1843
1844         err = 0;
1845         set_mm_exe_file(mm, exe.file);  /* this grabs a reference to exe.file */
1846 exit_unlock:
1847         up_write(&mm->mmap_sem);
1848
1849 exit:
1850         fdput(exe);
1851         return err;
1852 }
1853
1854 static int prctl_set_mm(int opt, unsigned long addr,
1855                         unsigned long arg4, unsigned long arg5)
1856 {
1857         unsigned long rlim = rlimit(RLIMIT_DATA);
1858         struct mm_struct *mm = current->mm;
1859         struct vm_area_struct *vma;
1860         int error;
1861
1862         if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
1863                 return -EINVAL;
1864
1865         if (!capable(CAP_SYS_RESOURCE))
1866                 return -EPERM;
1867
1868         if (opt == PR_SET_MM_EXE_FILE)
1869                 return prctl_set_mm_exe_file(mm, (unsigned int)addr);
1870
1871         if (addr >= TASK_SIZE || addr < mmap_min_addr)
1872                 return -EINVAL;
1873
1874         error = -EINVAL;
1875
1876         down_read(&mm->mmap_sem);
1877         vma = find_vma(mm, addr);
1878
1879         switch (opt) {
1880         case PR_SET_MM_START_CODE:
1881                 mm->start_code = addr;
1882                 break;
1883         case PR_SET_MM_END_CODE:
1884                 mm->end_code = addr;
1885                 break;
1886         case PR_SET_MM_START_DATA:
1887                 mm->start_data = addr;
1888                 break;
1889         case PR_SET_MM_END_DATA:
1890                 mm->end_data = addr;
1891                 break;
1892
1893         case PR_SET_MM_START_BRK:
1894                 if (addr <= mm->end_data)
1895                         goto out;
1896
1897                 if (rlim < RLIM_INFINITY &&
1898                     (mm->brk - addr) +
1899                     (mm->end_data - mm->start_data) > rlim)
1900                         goto out;
1901
1902                 mm->start_brk = addr;
1903                 break;
1904
1905         case PR_SET_MM_BRK:
1906                 if (addr <= mm->end_data)
1907                         goto out;
1908
1909                 if (rlim < RLIM_INFINITY &&
1910                     (addr - mm->start_brk) +
1911                     (mm->end_data - mm->start_data) > rlim)
1912                         goto out;
1913
1914                 mm->brk = addr;
1915                 break;
1916
1917         /*
1918          * If command line arguments and environment
1919          * are placed somewhere else on stack, we can
1920          * set them up here, ARG_START/END to setup
1921          * command line argumets and ENV_START/END
1922          * for environment.
1923          */
1924         case PR_SET_MM_START_STACK:
1925         case PR_SET_MM_ARG_START:
1926         case PR_SET_MM_ARG_END:
1927         case PR_SET_MM_ENV_START:
1928         case PR_SET_MM_ENV_END:
1929                 if (!vma) {
1930                         error = -EFAULT;
1931                         goto out;
1932                 }
1933                 if (opt == PR_SET_MM_START_STACK)
1934                         mm->start_stack = addr;
1935                 else if (opt == PR_SET_MM_ARG_START)
1936                         mm->arg_start = addr;
1937                 else if (opt == PR_SET_MM_ARG_END)
1938                         mm->arg_end = addr;
1939                 else if (opt == PR_SET_MM_ENV_START)
1940                         mm->env_start = addr;
1941                 else if (opt == PR_SET_MM_ENV_END)
1942                         mm->env_end = addr;
1943                 break;
1944
1945         /*
1946          * This doesn't move auxiliary vector itself
1947          * since it's pinned to mm_struct, but allow
1948          * to fill vector with new values. It's up
1949          * to a caller to provide sane values here
1950          * otherwise user space tools which use this
1951          * vector might be unhappy.
1952          */
1953         case PR_SET_MM_AUXV: {
1954                 unsigned long user_auxv[AT_VECTOR_SIZE];
1955
1956                 if (arg4 > sizeof(user_auxv))
1957                         goto out;
1958                 up_read(&mm->mmap_sem);
1959
1960                 if (copy_from_user(user_auxv, (const void __user *)addr, arg4))
1961                         return -EFAULT;
1962
1963                 /* Make sure the last entry is always AT_NULL */
1964                 user_auxv[AT_VECTOR_SIZE - 2] = 0;
1965                 user_auxv[AT_VECTOR_SIZE - 1] = 0;
1966
1967                 BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1968
1969                 task_lock(current);
1970                 memcpy(mm->saved_auxv, user_auxv, arg4);
1971                 task_unlock(current);
1972
1973                 return 0;
1974         }
1975         default:
1976                 goto out;
1977         }
1978
1979         error = 0;
1980 out:
1981         up_read(&mm->mmap_sem);
1982         return error;
1983 }
1984
1985 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1986 {
1987         return put_user(me->clear_child_tid, tid_addr);
1988 }
1989
1990 #else /* CONFIG_CHECKPOINT_RESTORE */
1991 static int prctl_set_mm(int opt, unsigned long addr,
1992                         unsigned long arg4, unsigned long arg5)
1993 {
1994         return -EINVAL;
1995 }
1996 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
1997 {
1998         return -EINVAL;
1999 }
2000 #endif
2001
2002 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2003                 unsigned long, arg4, unsigned long, arg5)
2004 {
2005         struct task_struct *me = current;
2006         unsigned char comm[sizeof(me->comm)];
2007         long error;
2008
2009         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2010         if (error != -ENOSYS)
2011                 return error;
2012
2013         error = 0;
2014         switch (option) {
2015                 case PR_SET_PDEATHSIG:
2016                         if (!valid_signal(arg2)) {
2017                                 error = -EINVAL;
2018                                 break;
2019                         }
2020                         me->pdeath_signal = arg2;
2021                         break;
2022                 case PR_GET_PDEATHSIG:
2023                         error = put_user(me->pdeath_signal, (int __user *)arg2);
2024                         break;
2025                 case PR_GET_DUMPABLE:
2026                         error = get_dumpable(me->mm);
2027                         break;
2028                 case PR_SET_DUMPABLE:
2029                         if (arg2 < 0 || arg2 > 1) {
2030                                 error = -EINVAL;
2031                                 break;
2032                         }
2033                         set_dumpable(me->mm, arg2);
2034                         break;
2035
2036                 case PR_SET_UNALIGN:
2037                         error = SET_UNALIGN_CTL(me, arg2);
2038                         break;
2039                 case PR_GET_UNALIGN:
2040                         error = GET_UNALIGN_CTL(me, arg2);
2041                         break;
2042                 case PR_SET_FPEMU:
2043                         error = SET_FPEMU_CTL(me, arg2);
2044                         break;
2045                 case PR_GET_FPEMU:
2046                         error = GET_FPEMU_CTL(me, arg2);
2047                         break;
2048                 case PR_SET_FPEXC:
2049                         error = SET_FPEXC_CTL(me, arg2);
2050                         break;
2051                 case PR_GET_FPEXC:
2052                         error = GET_FPEXC_CTL(me, arg2);
2053                         break;
2054                 case PR_GET_TIMING:
2055                         error = PR_TIMING_STATISTICAL;
2056                         break;
2057                 case PR_SET_TIMING:
2058                         if (arg2 != PR_TIMING_STATISTICAL)
2059                                 error = -EINVAL;
2060                         break;
2061                 case PR_SET_NAME:
2062                         comm[sizeof(me->comm)-1] = 0;
2063                         if (strncpy_from_user(comm, (char __user *)arg2,
2064                                               sizeof(me->comm) - 1) < 0)
2065                                 return -EFAULT;
2066                         set_task_comm(me, comm);
2067                         proc_comm_connector(me);
2068                         break;
2069                 case PR_GET_NAME:
2070                         get_task_comm(comm, me);
2071                         if (copy_to_user((char __user *)arg2, comm,
2072                                          sizeof(comm)))
2073                                 return -EFAULT;
2074                         break;
2075                 case PR_GET_ENDIAN:
2076                         error = GET_ENDIAN(me, arg2);
2077                         break;
2078                 case PR_SET_ENDIAN:
2079                         error = SET_ENDIAN(me, arg2);
2080                         break;
2081                 case PR_GET_SECCOMP:
2082                         error = prctl_get_seccomp();
2083                         break;
2084                 case PR_SET_SECCOMP:
2085                         error = prctl_set_seccomp(arg2, (char __user *)arg3);
2086                         break;
2087                 case PR_GET_TSC:
2088                         error = GET_TSC_CTL(arg2);
2089                         break;
2090                 case PR_SET_TSC:
2091                         error = SET_TSC_CTL(arg2);
2092                         break;
2093                 case PR_TASK_PERF_EVENTS_DISABLE:
2094                         error = perf_event_task_disable();
2095                         break;
2096                 case PR_TASK_PERF_EVENTS_ENABLE:
2097                         error = perf_event_task_enable();
2098                         break;
2099                 case PR_GET_TIMERSLACK:
2100                         error = current->timer_slack_ns;
2101                         break;
2102                 case PR_SET_TIMERSLACK:
2103                         if (arg2 <= 0)
2104                                 current->timer_slack_ns =
2105                                         current->default_timer_slack_ns;
2106                         else
2107                                 current->timer_slack_ns = arg2;
2108                         break;
2109                 case PR_MCE_KILL:
2110                         if (arg4 | arg5)
2111                                 return -EINVAL;
2112                         switch (arg2) {
2113                         case PR_MCE_KILL_CLEAR:
2114                                 if (arg3 != 0)
2115                                         return -EINVAL;
2116                                 current->flags &= ~PF_MCE_PROCESS;
2117                                 break;
2118                         case PR_MCE_KILL_SET:
2119                                 current->flags |= PF_MCE_PROCESS;
2120                                 if (arg3 == PR_MCE_KILL_EARLY)
2121                                         current->flags |= PF_MCE_EARLY;
2122                                 else if (arg3 == PR_MCE_KILL_LATE)
2123                                         current->flags &= ~PF_MCE_EARLY;
2124                                 else if (arg3 == PR_MCE_KILL_DEFAULT)
2125                                         current->flags &=
2126                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
2127                                 else
2128                                         return -EINVAL;
2129                                 break;
2130                         default:
2131                                 return -EINVAL;
2132                         }
2133                         break;
2134                 case PR_MCE_KILL_GET:
2135                         if (arg2 | arg3 | arg4 | arg5)
2136                                 return -EINVAL;
2137                         if (current->flags & PF_MCE_PROCESS)
2138                                 error = (current->flags & PF_MCE_EARLY) ?
2139                                         PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2140                         else
2141                                 error = PR_MCE_KILL_DEFAULT;
2142                         break;
2143                 case PR_SET_MM:
2144                         error = prctl_set_mm(arg2, arg3, arg4, arg5);
2145                         break;
2146                 case PR_GET_TID_ADDRESS:
2147                         error = prctl_get_tid_address(me, (int __user **)arg2);
2148                         break;
2149                 case PR_SET_CHILD_SUBREAPER:
2150                         me->signal->is_child_subreaper = !!arg2;
2151                         break;
2152                 case PR_GET_CHILD_SUBREAPER:
2153                         error = put_user(me->signal->is_child_subreaper,
2154                                          (int __user *) arg2);
2155                         break;
2156                 case PR_SET_NO_NEW_PRIVS:
2157                         if (arg2 != 1 || arg3 || arg4 || arg5)
2158                                 return -EINVAL;
2159
2160                         current->no_new_privs = 1;
2161                         break;
2162                 case PR_GET_NO_NEW_PRIVS:
2163                         if (arg2 || arg3 || arg4 || arg5)
2164                                 return -EINVAL;
2165                         return current->no_new_privs ? 1 : 0;
2166                 default:
2167                         error = -EINVAL;
2168                         break;
2169         }
2170         return error;
2171 }
2172
2173 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2174                 struct getcpu_cache __user *, unused)
2175 {
2176         int err = 0;
2177         int cpu = raw_smp_processor_id();
2178         if (cpup)
2179                 err |= put_user(cpu, cpup);
2180         if (nodep)
2181                 err |= put_user(cpu_to_node(cpu), nodep);
2182         return err ? -EFAULT : 0;
2183 }
2184
2185 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
2186
2187 static void argv_cleanup(struct subprocess_info *info)
2188 {
2189         argv_free(info->argv);
2190 }
2191
2192 static int __orderly_poweroff(void)
2193 {
2194         int argc;
2195         char **argv;
2196         static char *envp[] = {
2197                 "HOME=/",
2198                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
2199                 NULL
2200         };
2201         int ret;
2202
2203         argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
2204         if (argv == NULL) {
2205                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
2206                        __func__, poweroff_cmd);
2207                 return -ENOMEM;
2208         }
2209
2210         ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_WAIT_EXEC,
2211                                       NULL, argv_cleanup, NULL);
2212         if (ret == -ENOMEM)
2213                 argv_free(argv);
2214
2215         return ret;
2216 }
2217
2218 /**
2219  * orderly_poweroff - Trigger an orderly system poweroff
2220  * @force: force poweroff if command execution fails
2221  *
2222  * This may be called from any context to trigger a system shutdown.
2223  * If the orderly shutdown fails, it will force an immediate shutdown.
2224  */
2225 int orderly_poweroff(bool force)
2226 {
2227         int ret = __orderly_poweroff();
2228
2229         if (ret && force) {
2230                 printk(KERN_WARNING "Failed to start orderly shutdown: "
2231                        "forcing the issue\n");
2232
2233                 /*
2234                  * I guess this should try to kick off some daemon to sync and
2235                  * poweroff asap.  Or not even bother syncing if we're doing an
2236                  * emergency shutdown?
2237                  */
2238                 emergency_sync();
2239                 kernel_power_off();
2240         }
2241
2242         return ret;
2243 }
2244 EXPORT_SYMBOL_GPL(orderly_poweroff);