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   1 /*
   2  *  linux/kernel/sys.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/mm.h>
   9 #include <linux/utsname.h>
  10 #include <linux/mman.h>
  11 #include <linux/smp_lock.h>
  12 #include <linux/notifier.h>
  13 #include <linux/reboot.h>
  14 #include <linux/prctl.h>
  15 #include <linux/highuid.h>
  16 #include <linux/fs.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/ptrace.h>
  37
  38 #include <linux/compat.h>
  39 #include <linux/syscalls.h>
  40 #include <linux/kprobes.h>
  41 #include <linux/user_namespace.h>
  42
  43 #include <asm/uaccess.h>
  44 #include <asm/io.h>
  45 #include <asm/unistd.h>
  46
  47 #ifndef SET_UNALIGN_CTL
  48 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  49 #endif
  50 #ifndef GET_UNALIGN_CTL
  51 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  52 #endif
  53 #ifndef SET_FPEMU_CTL
  54 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  55 #endif
  56 #ifndef GET_FPEMU_CTL
  57 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  58 #endif
  59 #ifndef SET_FPEXC_CTL
  60 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  61 #endif
  62 #ifndef GET_FPEXC_CTL
  63 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  64 #endif
  65 #ifndef GET_ENDIAN
  66 # define GET_ENDIAN(a,b)        (-EINVAL)
  67 #endif
  68 #ifndef SET_ENDIAN
  69 # define SET_ENDIAN(a,b)        (-EINVAL)
  70 #endif
  71 #ifndef GET_TSC_CTL
  72 # define GET_TSC_CTL(a)         (-EINVAL)
  73 #endif
  74 #ifndef SET_TSC_CTL
  75 # define SET_TSC_CTL(a)         (-EINVAL)
  76 #endif
  77
  78 /*
  79  * this is where the system-wide overflow UID and GID are defined, for
  80  * architectures that now have 32-bit UID/GID but didn't in the past
  81  */
  82
  83 int overflowuid = DEFAULT_OVERFLOWUID;
  84 int overflowgid = DEFAULT_OVERFLOWGID;
  85
  86 #ifdef CONFIG_UID16
  87 EXPORT_SYMBOL(overflowuid);
  88 EXPORT_SYMBOL(overflowgid);
  89 #endif
  90
  91 /*
  92  * the same as above, but for filesystems which can only store a 16-bit
  93  * UID and GID. as such, this is needed on all architectures
  94  */
  95
  96 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  97 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
  98
  99 EXPORT_SYMBOL(fs_overflowuid);
 100 EXPORT_SYMBOL(fs_overflowgid);
 101
 102 /*
 103  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
 104  */
 105
 106 int C_A_D = 1;
 107 struct pid *cad_pid;
 108 EXPORT_SYMBOL(cad_pid);
 109
 110 /*
 111  * If set, this is used for preparing the system to power off.
 112  */
 113
 114 void (*pm_power_off_prepare)(void);
 115
 116 /*
 117  * set the priority of a task
 118  * - the caller must hold the RCU read lock
 119  */
 120 static int set_one_prio(struct task_struct *p, int niceval, int error)
 121 {
 122         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 123         int no_nice;
 124
 125         if (pcred->uid  != cred->euid &&
 126             pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
 127                 error = -EPERM;
 128                 goto out;
 129         }
 130         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 131                 error = -EACCES;
 132                 goto out;
 133         }
 134         no_nice = security_task_setnice(p, niceval);
 135         if (no_nice) {
 136                 error = no_nice;
 137                 goto out;
 138         }
 139         if (error == -ESRCH)
 140                 error = 0;
 141         set_user_nice(p, niceval);
 142 out:
 143         return error;
 144 }
 145
 146 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 147 {
 148         struct task_struct *g, *p;
 149         struct user_struct *user;
 150         const struct cred *cred = current_cred();
 151         int error = -EINVAL;
 152         struct pid *pgrp;
 153
 154         if (which > PRIO_USER || which < PRIO_PROCESS)
 155                 goto out;
 156
 157         /* normalize: avoid signed division (rounding problems) */
 158         error = -ESRCH;
 159         if (niceval < -20)
 160                 niceval = -20;
 161         if (niceval > 19)
 162                 niceval = 19;
 163
 164         read_lock(&tasklist_lock);
 165         switch (which) {
 166                 case PRIO_PROCESS:
 167                         if (who)
 168                                 p = find_task_by_vpid(who);
 169                         else
 170                                 p = current;
 171                         if (p)
 172                                 error = set_one_prio(p, niceval, error);
 173                         break;
 174                 case PRIO_PGRP:
 175                         if (who)
 176                                 pgrp = find_vpid(who);
 177                         else
 178                                 pgrp = task_pgrp(current);
 179                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 180                                 error = set_one_prio(p, niceval, error);
 181                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 182                         break;
 183                 case PRIO_USER:
 184                         user = (struct user_struct *) cred->user;
 185                         if (!who)
 186                                 who = cred->uid;
 187                         else if ((who != cred->uid) &&
 188                                  !(user = find_user(who)))
 189                                 goto out_unlock;        /* No processes for this user */
 190
 191                         do_each_thread(g, p)
 192                                 if (__task_cred(p)->uid == who)
 193                                         error = set_one_prio(p, niceval, error);
 194                         while_each_thread(g, p);
 195                         if (who != cred->uid)
 196                                 free_uid(user);         /* For find_user() */
 197                         break;
 198         }
 199 out_unlock:
 200         read_unlock(&tasklist_lock);
 201 out:
 202         return error;
 203 }
 204
 205 /*
 206  * Ugh. To avoid negative return values, "getpriority()" will
 207  * not return the normal nice-value, but a negated value that
 208  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 209  * to stay compatible.
 210  */
 211 SYSCALL_DEFINE2(getpriority, int, which, int, who)
 212 {
 213         struct task_struct *g, *p;
 214         struct user_struct *user;
 215         const struct cred *cred = current_cred();
 216         long niceval, retval = -ESRCH;
 217         struct pid *pgrp;
 218
 219         if (which > PRIO_USER || which < PRIO_PROCESS)
 220                 return -EINVAL;
 221
 222         read_lock(&tasklist_lock);
 223         switch (which) {
 224                 case PRIO_PROCESS:
 225                         if (who)
 226                                 p = find_task_by_vpid(who);
 227                         else
 228                                 p = current;
 229                         if (p) {
 230                                 niceval = 20 - task_nice(p);
 231                                 if (niceval > retval)
 232                                         retval = niceval;
 233                         }
 234                         break;
 235                 case PRIO_PGRP:
 236                         if (who)
 237                                 pgrp = find_vpid(who);
 238                         else
 239                                 pgrp = task_pgrp(current);
 240                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 241                                 niceval = 20 - task_nice(p);
 242                                 if (niceval > retval)
 243                                         retval = niceval;
 244                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 245                         break;
 246                 case PRIO_USER:
 247                         user = (struct user_struct *) cred->user;
 248                         if (!who)
 249                                 who = cred->uid;
 250                         else if ((who != cred->uid) &&
 251                                  !(user = find_user(who)))
 252                                 goto out_unlock;        /* No processes for this user */
 253
 254                         do_each_thread(g, p)
 255                                 if (__task_cred(p)->uid == who) {
 256                                         niceval = 20 - task_nice(p);
 257                                         if (niceval > retval)
 258                                                 retval = niceval;
 259                                 }
 260                         while_each_thread(g, p);
 261                         if (who != cred->uid)
 262                                 free_uid(user);         /* for find_user() */
 263                         break;
 264         }
 265 out_unlock:
 266         read_unlock(&tasklist_lock);
 267
 268         return retval;
 269 }
 270
 271 /**
 272  *      emergency_restart - reboot the system
 273  *
 274  *      Without shutting down any hardware or taking any locks
 275  *      reboot the system.  This is called when we know we are in
 276  *      trouble so this is our best effort to reboot.  This is
 277  *      safe to call in interrupt context.
 278  */
 279 void emergency_restart(void)
 280 {
 281         machine_emergency_restart();
 282 }
 283 EXPORT_SYMBOL_GPL(emergency_restart);
 284
 285 void kernel_restart_prepare(char *cmd)
 286 {
 287         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 288         system_state = SYSTEM_RESTART;
 289         device_shutdown();
 290         sysdev_shutdown();
 291 }
 292
 293 /**
 294  *      kernel_restart - reboot the system
 295  *      @cmd: pointer to buffer containing command to execute for restart
 296  *              or %NULL
 297  *
 298  *      Shutdown everything and perform a clean reboot.
 299  *      This is not safe to call in interrupt context.
 300  */
 301 void kernel_restart(char *cmd)
 302 {
 303         kernel_restart_prepare(cmd);
 304         if (!cmd)
 305                 printk(KERN_EMERG "Restarting system.\n");
 306         else
 307                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 308         machine_restart(cmd);
 309 }
 310 EXPORT_SYMBOL_GPL(kernel_restart);
 311
 312 static void kernel_shutdown_prepare(enum system_states state)
 313 {
 314         blocking_notifier_call_chain(&reboot_notifier_list,
 315                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 316         system_state = state;
 317         device_shutdown();
 318 }
 319 /**
 320  *      kernel_halt - halt the system
 321  *
 322  *      Shutdown everything and perform a clean system halt.
 323  */
 324 void kernel_halt(void)
 325 {
 326         kernel_shutdown_prepare(SYSTEM_HALT);
 327         sysdev_shutdown();
 328         printk(KERN_EMERG "System halted.\n");
 329         machine_halt();
 330 }
 331
 332 EXPORT_SYMBOL_GPL(kernel_halt);
 333
 334 /**
 335  *      kernel_power_off - power_off the system
 336  *
 337  *      Shutdown everything and perform a clean system power_off.
 338  */
 339 void kernel_power_off(void)
 340 {
 341         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 342         if (pm_power_off_prepare)
 343                 pm_power_off_prepare();
 344         disable_nonboot_cpus();
 345         sysdev_shutdown();
 346         printk(KERN_EMERG "Power down.\n");
 347         machine_power_off();
 348 }
 349 EXPORT_SYMBOL_GPL(kernel_power_off);
 350 /*
 351  * Reboot system call: for obvious reasons only root may call it,
 352  * and even root needs to set up some magic numbers in the registers
 353  * so that some mistake won't make this reboot the whole machine.
 354  * You can also set the meaning of the ctrl-alt-del-key here.
 355  *
 356  * reboot doesn't sync: do that yourself before calling this.
 357  */
 358 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 359                 void __user *, arg)
 360 {
 361         char buffer[256];
 362
 363         /* We only trust the superuser with rebooting the system. */
 364         if (!capable(CAP_SYS_BOOT))
 365                 return -EPERM;
 366
 367         /* For safety, we require "magic" arguments. */
 368         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 369             (magic2 != LINUX_REBOOT_MAGIC2 &&
 370                         magic2 != LINUX_REBOOT_MAGIC2A &&
 371                         magic2 != LINUX_REBOOT_MAGIC2B &&
 372                         magic2 != LINUX_REBOOT_MAGIC2C))
 373                 return -EINVAL;
 374
 375         /* Instead of trying to make the power_off code look like
 376          * halt when pm_power_off is not set do it the easy way.
 377          */
 378         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 379                 cmd = LINUX_REBOOT_CMD_HALT;
 380
 381         lock_kernel();
 382         switch (cmd) {
 383         case LINUX_REBOOT_CMD_RESTART:
 384                 kernel_restart(NULL);
 385                 break;
 386
 387         case LINUX_REBOOT_CMD_CAD_ON:
 388                 C_A_D = 1;
 389                 break;
 390
 391         case LINUX_REBOOT_CMD_CAD_OFF:
 392                 C_A_D = 0;
 393                 break;
 394
 395         case LINUX_REBOOT_CMD_HALT:
 396                 kernel_halt();
 397                 unlock_kernel();
 398                 do_exit(0);
 399                 break;
 400
 401         case LINUX_REBOOT_CMD_POWER_OFF:
 402                 kernel_power_off();
 403                 unlock_kernel();
 404                 do_exit(0);
 405                 break;
 406
 407         case LINUX_REBOOT_CMD_RESTART2:
 408                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 409                         unlock_kernel();
 410                         return -EFAULT;
 411                 }
 412                 buffer[sizeof(buffer) - 1] = '\0';
 413
 414                 kernel_restart(buffer);
 415                 break;
 416
 417 #ifdef CONFIG_KEXEC
 418         case LINUX_REBOOT_CMD_KEXEC:
 419                 {
 420                         int ret;
 421                         ret = kernel_kexec();
 422                         unlock_kernel();
 423                         return ret;
 424                 }
 425 #endif
 426
 427 #ifdef CONFIG_HIBERNATION
 428         case LINUX_REBOOT_CMD_SW_SUSPEND:
 429                 {
 430                         int ret = hibernate();
 431                         unlock_kernel();
 432                         return ret;
 433                 }
 434 #endif
 435
 436         default:
 437                 unlock_kernel();
 438                 return -EINVAL;
 439         }
 440         unlock_kernel();
 441         return 0;
 442 }
 443
 444 static void deferred_cad(struct work_struct *dummy)
 445 {
 446         kernel_restart(NULL);
 447 }
 448
 449 /*
 450  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 451  * As it's called within an interrupt, it may NOT sync: the only choice
 452  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 453  */
 454 void ctrl_alt_del(void)
 455 {
 456         static DECLARE_WORK(cad_work, deferred_cad);
 457
 458         if (C_A_D)
 459                 schedule_work(&cad_work);
 460         else
 461                 kill_cad_pid(SIGINT, 1);
 462 }
 463
 464 /*
 465  * Unprivileged users may change the real gid to the effective gid
 466  * or vice versa.  (BSD-style)
 467  *
 468  * If you set the real gid at all, or set the effective gid to a value not
 469  * equal to the real gid, then the saved gid is set to the new effective gid.
 470  *
 471  * This makes it possible for a setgid program to completely drop its
 472  * privileges, which is often a useful assertion to make when you are doing
 473  * a security audit over a program.
 474  *
 475  * The general idea is that a program which uses just setregid() will be
 476  * 100% compatible with BSD.  A program which uses just setgid() will be
 477  * 100% compatible with POSIX with saved IDs.
 478  *
 479  * SMP: There are not races, the GIDs are checked only by filesystem
 480  *      operations (as far as semantic preservation is concerned).
 481  */
 482 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 483 {
 484         const struct cred *old;
 485         struct cred *new;
 486         int retval;
 487
 488         new = prepare_creds();
 489         if (!new)
 490                 return -ENOMEM;
 491         old = current_cred();
 492
 493         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 494         if (retval)
 495                 goto error;
 496
 497         retval = -EPERM;
 498         if (rgid != (gid_t) -1) {
 499                 if (old->gid == rgid ||
 500                     old->egid == rgid ||
 501                     capable(CAP_SETGID))
 502                         new->gid = rgid;
 503                 else
 504                         goto error;
 505         }
 506         if (egid != (gid_t) -1) {
 507                 if (old->gid == egid ||
 508                     old->egid == egid ||
 509                     old->sgid == egid ||
 510                     capable(CAP_SETGID))
 511                         new->egid = egid;
 512                 else
 513                         goto error;
 514         }
 515
 516         if (rgid != (gid_t) -1 ||
 517             (egid != (gid_t) -1 && egid != old->gid))
 518                 new->sgid = new->egid;
 519         new->fsgid = new->egid;
 520
 521         return commit_creds(new);
 522
 523 error:
 524         abort_creds(new);
 525         return retval;
 526 }
 527
 528 /*
 529  * setgid() is implemented like SysV w/ SAVED_IDS
 530  *
 531  * SMP: Same implicit races as above.
 532  */
 533 SYSCALL_DEFINE1(setgid, gid_t, gid)
 534 {
 535         const struct cred *old;
 536         struct cred *new;
 537         int retval;
 538
 539         new = prepare_creds();
 540         if (!new)
 541                 return -ENOMEM;
 542         old = current_cred();
 543
 544         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 545         if (retval)
 546                 goto error;
 547
 548         retval = -EPERM;
 549         if (capable(CAP_SETGID))
 550                 new->gid = new->egid = new->sgid = new->fsgid = gid;
 551         else if (gid == old->gid || gid == old->sgid)
 552                 new->egid = new->fsgid = gid;
 553         else
 554                 goto error;
 555
 556         return commit_creds(new);
 557
 558 error:
 559         abort_creds(new);
 560         return retval;
 561 }
 562
 563 /*
 564  * change the user struct in a credentials set to match the new UID
 565  */
 566 static int set_user(struct cred *new)
 567 {
 568         struct user_struct *new_user;
 569
 570         new_user = alloc_uid(current_user_ns(), new->uid);
 571         if (!new_user)
 572                 return -EAGAIN;
 573
 574         if (!task_can_switch_user(new_user, current)) {
 575                 free_uid(new_user);
 576                 return -EINVAL;
 577         }
 578
 579         if (atomic_read(&new_user->processes) >=
 580                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 581                         new_user != INIT_USER) {
 582                 free_uid(new_user);
 583                 return -EAGAIN;
 584         }
 585
 586         free_uid(new->user);
 587         new->user = new_user;
 588         return 0;
 589 }
 590
 591 /*
 592  * Unprivileged users may change the real uid to the effective uid
 593  * or vice versa.  (BSD-style)
 594  *
 595  * If you set the real uid at all, or set the effective uid to a value not
 596  * equal to the real uid, then the saved uid is set to the new effective uid.
 597  *
 598  * This makes it possible for a setuid program to completely drop its
 599  * privileges, which is often a useful assertion to make when you are doing
 600  * a security audit over a program.
 601  *
 602  * The general idea is that a program which uses just setreuid() will be
 603  * 100% compatible with BSD.  A program which uses just setuid() will be
 604  * 100% compatible with POSIX with saved IDs.
 605  */
 606 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 607 {
 608         const struct cred *old;
 609         struct cred *new;
 610         int retval;
 611
 612         new = prepare_creds();
 613         if (!new)
 614                 return -ENOMEM;
 615         old = current_cred();
 616
 617         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 618         if (retval)
 619                 goto error;
 620
 621         retval = -EPERM;
 622         if (ruid != (uid_t) -1) {
 623                 new->uid = ruid;
 624                 if (old->uid != ruid &&
 625                     old->euid != ruid &&
 626                     !capable(CAP_SETUID))
 627                         goto error;
 628         }
 629
 630         if (euid != (uid_t) -1) {
 631                 new->euid = euid;
 632                 if (old->uid != euid &&
 633                     old->euid != euid &&
 634                     old->suid != euid &&
 635                     !capable(CAP_SETUID))
 636                         goto error;
 637         }
 638
 639         if (new->uid != old->uid) {
 640                 retval = set_user(new);
 641                 if (retval < 0)
 642                         goto error;
 643         }
 644         if (ruid != (uid_t) -1 ||
 645             (euid != (uid_t) -1 && euid != old->uid))
 646                 new->suid = new->euid;
 647         new->fsuid = new->euid;
 648
 649         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 650         if (retval < 0)
 651                 goto error;
 652
 653         return commit_creds(new);
 654
 655 error:
 656         abort_creds(new);
 657         return retval;
 658 }
 659
 660 /*
 661  * setuid() is implemented like SysV with SAVED_IDS
 662  *
 663  * Note that SAVED_ID's is deficient in that a setuid root program
 664  * like sendmail, for example, cannot set its uid to be a normal
 665  * user and then switch back, because if you're root, setuid() sets
 666  * the saved uid too.  If you don't like this, blame the bright people
 667  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 668  * will allow a root program to temporarily drop privileges and be able to
 669  * regain them by swapping the real and effective uid.
 670  */
 671 SYSCALL_DEFINE1(setuid, uid_t, uid)
 672 {
 673         const struct cred *old;
 674         struct cred *new;
 675         int retval;
 676
 677         new = prepare_creds();
 678         if (!new)
 679                 return -ENOMEM;
 680         old = current_cred();
 681
 682         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 683         if (retval)
 684                 goto error;
 685
 686         retval = -EPERM;
 687         if (capable(CAP_SETUID)) {
 688                 new->suid = new->uid = uid;
 689                 if (uid != old->uid) {
 690                         retval = set_user(new);
 691                         if (retval < 0)
 692                                 goto error;
 693                 }
 694         } else if (uid != old->uid && uid != new->suid) {
 695                 goto error;
 696         }
 697
 698         new->fsuid = new->euid = uid;
 699
 700         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 701         if (retval < 0)
 702                 goto error;
 703
 704         return commit_creds(new);
 705
 706 error:
 707         abort_creds(new);
 708         return retval;
 709 }
 710
 711
 712 /*
 713  * This function implements a generic ability to update ruid, euid,
 714  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 715  */
 716 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 717 {
 718         const struct cred *old;
 719         struct cred *new;
 720         int retval;
 721
 722         new = prepare_creds();
 723         if (!new)
 724                 return -ENOMEM;
 725
 726         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 727         if (retval)
 728                 goto error;
 729         old = current_cred();
 730
 731         retval = -EPERM;
 732         if (!capable(CAP_SETUID)) {
 733                 if (ruid != (uid_t) -1 && ruid != old->uid &&
 734                     ruid != old->euid  && ruid != old->suid)
 735                         goto error;
 736                 if (euid != (uid_t) -1 && euid != old->uid &&
 737                     euid != old->euid  && euid != old->suid)
 738                         goto error;
 739                 if (suid != (uid_t) -1 && suid != old->uid &&
 740                     suid != old->euid  && suid != old->suid)
 741                         goto error;
 742         }
 743
 744         if (ruid != (uid_t) -1) {
 745                 new->uid = ruid;
 746                 if (ruid != old->uid) {
 747                         retval = set_user(new);
 748                         if (retval < 0)
 749                                 goto error;
 750                 }
 751         }
 752         if (euid != (uid_t) -1)
 753                 new->euid = euid;
 754         if (suid != (uid_t) -1)
 755                 new->suid = suid;
 756         new->fsuid = new->euid;
 757
 758         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 759         if (retval < 0)
 760                 goto error;
 761
 762         return commit_creds(new);
 763
 764 error:
 765         abort_creds(new);
 766         return retval;
 767 }
 768
 769 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
 770 {
 771         const struct cred *cred = current_cred();
 772         int retval;
 773
 774         if (!(retval   = put_user(cred->uid,  ruid)) &&
 775             !(retval   = put_user(cred->euid, euid)))
 776                 retval = put_user(cred->suid, suid);
 777
 778         return retval;
 779 }
 780
 781 /*
 782  * Same as above, but for rgid, egid, sgid.
 783  */
 784 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 785 {
 786         const struct cred *old;
 787         struct cred *new;
 788         int retval;
 789
 790         new = prepare_creds();
 791         if (!new)
 792                 return -ENOMEM;
 793         old = current_cred();
 794
 795         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 796         if (retval)
 797                 goto error;
 798
 799         retval = -EPERM;
 800         if (!capable(CAP_SETGID)) {
 801                 if (rgid != (gid_t) -1 && rgid != old->gid &&
 802                     rgid != old->egid  && rgid != old->sgid)
 803                         goto error;
 804                 if (egid != (gid_t) -1 && egid != old->gid &&
 805                     egid != old->egid  && egid != old->sgid)
 806                         goto error;
 807                 if (sgid != (gid_t) -1 && sgid != old->gid &&
 808                     sgid != old->egid  && sgid != old->sgid)
 809                         goto error;
 810         }
 811
 812         if (rgid != (gid_t) -1)
 813                 new->gid = rgid;
 814         if (egid != (gid_t) -1)
 815                 new->egid = egid;
 816         if (sgid != (gid_t) -1)
 817                 new->sgid = sgid;
 818         new->fsgid = new->egid;
 819
 820         return commit_creds(new);
 821
 822 error:
 823         abort_creds(new);
 824         return retval;
 825 }
 826
 827 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
 828 {
 829         const struct cred *cred = current_cred();
 830         int retval;
 831
 832         if (!(retval   = put_user(cred->gid,  rgid)) &&
 833             !(retval   = put_user(cred->egid, egid)))
 834                 retval = put_user(cred->sgid, sgid);
 835
 836         return retval;
 837 }
 838
 839
 840 /*
 841  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 842  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 843  * whatever uid it wants to). It normally shadows "euid", except when
 844  * explicitly set by setfsuid() or for access..
 845  */
 846 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 847 {
 848         const struct cred *old;
 849         struct cred *new;
 850         uid_t old_fsuid;
 851
 852         new = prepare_creds();
 853         if (!new)
 854                 return current_fsuid();
 855         old = current_cred();
 856         old_fsuid = old->fsuid;
 857
 858         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS) < 0)
 859                 goto error;
 860
 861         if (uid == old->uid  || uid == old->euid  ||
 862             uid == old->suid || uid == old->fsuid ||
 863             capable(CAP_SETUID)) {
 864                 if (uid != old_fsuid) {
 865                         new->fsuid = uid;
 866                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 867                                 goto change_okay;
 868                 }
 869         }
 870
 871 error:
 872         abort_creds(new);
 873         return old_fsuid;
 874
 875 change_okay:
 876         commit_creds(new);
 877         return old_fsuid;
 878 }
 879
 880 /*
 881  * Samma på svenska..
 882  */
 883 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
 884 {
 885         const struct cred *old;
 886         struct cred *new;
 887         gid_t old_fsgid;
 888
 889         new = prepare_creds();
 890         if (!new)
 891                 return current_fsgid();
 892         old = current_cred();
 893         old_fsgid = old->fsgid;
 894
 895         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 896                 goto error;
 897
 898         if (gid == old->gid  || gid == old->egid  ||
 899             gid == old->sgid || gid == old->fsgid ||
 900             capable(CAP_SETGID)) {
 901                 if (gid != old_fsgid) {
 902                         new->fsgid = gid;
 903                         goto change_okay;
 904                 }
 905         }
 906
 907 error:
 908         abort_creds(new);
 909         return old_fsgid;
 910
 911 change_okay:
 912         commit_creds(new);
 913         return old_fsgid;
 914 }
 915
 916 void do_sys_times(struct tms *tms)
 917 {
 918         struct task_cputime cputime;
 919         cputime_t cutime, cstime;
 920
 921         thread_group_cputime(current, &cputime);
 922         spin_lock_irq(&current->sighand->siglock);
 923         cutime = current->signal->cutime;
 924         cstime = current->signal->cstime;
 925         spin_unlock_irq(&current->sighand->siglock);
 926         tms->tms_utime = cputime_to_clock_t(cputime.utime);
 927         tms->tms_stime = cputime_to_clock_t(cputime.stime);
 928         tms->tms_cutime = cputime_to_clock_t(cutime);
 929         tms->tms_cstime = cputime_to_clock_t(cstime);
 930 }
 931
 932 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
 933 {
 934         if (tbuf) {
 935                 struct tms tmp;
 936
 937                 do_sys_times(&tmp);
 938                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 939                         return -EFAULT;
 940         }
 941         force_successful_syscall_return();
 942         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 943 }
 944
 945 /*
 946  * This needs some heavy checking ...
 947  * I just haven't the stomach for it. I also don't fully
 948  * understand sessions/pgrp etc. Let somebody who does explain it.
 949  *
 950  * OK, I think I have the protection semantics right.... this is really
 951  * only important on a multi-user system anyway, to make sure one user
 952  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 953  *
 954  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 955  * LBT 04.03.94
 956  */
 957 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
 958 {
 959         struct task_struct *p;
 960         struct task_struct *group_leader = current->group_leader;
 961         struct pid *pgrp;
 962         int err;
 963
 964         if (!pid)
 965                 pid = task_pid_vnr(group_leader);
 966         if (!pgid)
 967                 pgid = pid;
 968         if (pgid < 0)
 969                 return -EINVAL;
 970
 971         /* From this point forward we keep holding onto the tasklist lock
 972          * so that our parent does not change from under us. -DaveM
 973          */
 974         write_lock_irq(&tasklist_lock);
 975
 976         err = -ESRCH;
 977         p = find_task_by_vpid(pid);
 978         if (!p)
 979                 goto out;
 980
 981         err = -EINVAL;
 982         if (!thread_group_leader(p))
 983                 goto out;
 984
 985         if (same_thread_group(p->real_parent, group_leader)) {
 986                 err = -EPERM;
 987                 if (task_session(p) != task_session(group_leader))
 988                         goto out;
 989                 err = -EACCES;
 990                 if (p->did_exec)
 991                         goto out;
 992         } else {
 993                 err = -ESRCH;
 994                 if (p != group_leader)
 995                         goto out;
 996         }
 997
 998         err = -EPERM;
 999         if (p->signal->leader)
1000                 goto out;
1001
1002         pgrp = task_pid(p);
1003         if (pgid != pid) {
1004                 struct task_struct *g;
1005
1006                 pgrp = find_vpid(pgid);
1007                 g = pid_task(pgrp, PIDTYPE_PGID);
1008                 if (!g || task_session(g) != task_session(group_leader))
1009                         goto out;
1010         }
1011
1012         err = security_task_setpgid(p, pgid);
1013         if (err)
1014                 goto out;
1015
1016         if (task_pgrp(p) != pgrp)
1017                 change_pid(p, PIDTYPE_PGID, pgrp);
1018
1019         err = 0;
1020 out:
1021         /* All paths lead to here, thus we are safe. -DaveM */
1022         write_unlock_irq(&tasklist_lock);
1023         return err;
1024 }
1025
1026 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1027 {
1028         struct task_struct *p;
1029         struct pid *grp;
1030         int retval;
1031
1032         rcu_read_lock();
1033         if (!pid)
1034                 grp = task_pgrp(current);
1035         else {
1036                 retval = -ESRCH;
1037                 p = find_task_by_vpid(pid);
1038                 if (!p)
1039                         goto out;
1040                 grp = task_pgrp(p);
1041                 if (!grp)
1042                         goto out;
1043
1044                 retval = security_task_getpgid(p);
1045                 if (retval)
1046                         goto out;
1047         }
1048         retval = pid_vnr(grp);
1049 out:
1050         rcu_read_unlock();
1051         return retval;
1052 }
1053
1054 #ifdef __ARCH_WANT_SYS_GETPGRP
1055
1056 SYSCALL_DEFINE0(getpgrp)
1057 {
1058         return sys_getpgid(0);
1059 }
1060
1061 #endif
1062
1063 SYSCALL_DEFINE1(getsid, pid_t, pid)
1064 {
1065         struct task_struct *p;
1066         struct pid *sid;
1067         int retval;
1068
1069         rcu_read_lock();
1070         if (!pid)
1071                 sid = task_session(current);
1072         else {
1073                 retval = -ESRCH;
1074                 p = find_task_by_vpid(pid);
1075                 if (!p)
1076                         goto out;
1077                 sid = task_session(p);
1078                 if (!sid)
1079                         goto out;
1080
1081                 retval = security_task_getsid(p);
1082                 if (retval)
1083                         goto out;
1084         }
1085         retval = pid_vnr(sid);
1086 out:
1087         rcu_read_unlock();
1088         return retval;
1089 }
1090
1091 SYSCALL_DEFINE0(setsid)
1092 {
1093         struct task_struct *group_leader = current->group_leader;
1094         struct pid *sid = task_pid(group_leader);
1095         pid_t session = pid_vnr(sid);
1096         int err = -EPERM;
1097
1098         write_lock_irq(&tasklist_lock);
1099         /* Fail if I am already a session leader */
1100         if (group_leader->signal->leader)
1101                 goto out;
1102
1103         /* Fail if a process group id already exists that equals the
1104          * proposed session id.
1105          */
1106         if (pid_task(sid, PIDTYPE_PGID))
1107                 goto out;
1108
1109         group_leader->signal->leader = 1;
1110         __set_special_pids(sid);
1111
1112         proc_clear_tty(group_leader);
1113
1114         err = session;
1115 out:
1116         write_unlock_irq(&tasklist_lock);
1117         return err;
1118 }
1119
1120 /*
1121  * Supplementary group IDs
1122  */
1123
1124 /* init to 2 - one for init_task, one to ensure it is never freed */
1125 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1126
1127 struct group_info *groups_alloc(int gidsetsize)
1128 {
1129         struct group_info *group_info;
1130         int nblocks;
1131         int i;
1132
1133         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1134         /* Make sure we always allocate at least one indirect block pointer */
1135         nblocks = nblocks ? : 1;
1136         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1137         if (!group_info)
1138                 return NULL;
1139         group_info->ngroups = gidsetsize;
1140         group_info->nblocks = nblocks;
1141         atomic_set(&group_info->usage, 1);
1142
1143         if (gidsetsize <= NGROUPS_SMALL)
1144                 group_info->blocks[0] = group_info->small_block;
1145         else {
1146                 for (i = 0; i < nblocks; i++) {
1147                         gid_t *b;
1148                         b = (void *)__get_free_page(GFP_USER);
1149                         if (!b)
1150                                 goto out_undo_partial_alloc;
1151                         group_info->blocks[i] = b;
1152                 }
1153         }
1154         return group_info;
1155
1156 out_undo_partial_alloc:
1157         while (--i >= 0) {
1158                 free_page((unsigned long)group_info->blocks[i]);
1159         }
1160         kfree(group_info);
1161         return NULL;
1162 }
1163
1164 EXPORT_SYMBOL(groups_alloc);
1165
1166 void groups_free(struct group_info *group_info)
1167 {
1168         if (group_info->blocks[0] != group_info->small_block) {
1169                 int i;
1170                 for (i = 0; i < group_info->nblocks; i++)
1171                         free_page((unsigned long)group_info->blocks[i]);
1172         }
1173         kfree(group_info);
1174 }
1175
1176 EXPORT_SYMBOL(groups_free);
1177
1178 /* export the group_info to a user-space array */
1179 static int groups_to_user(gid_t __user *grouplist,
1180                           const struct group_info *group_info)
1181 {
1182         int i;
1183         unsigned int count = group_info->ngroups;
1184
1185         for (i = 0; i < group_info->nblocks; i++) {
1186                 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1187                 unsigned int len = cp_count * sizeof(*grouplist);
1188
1189                 if (copy_to_user(grouplist, group_info->blocks[i], len))
1190                         return -EFAULT;
1191
1192                 grouplist += NGROUPS_PER_BLOCK;
1193                 count -= cp_count;
1194         }
1195         return 0;
1196 }
1197
1198 /* fill a group_info from a user-space array - it must be allocated already */
1199 static int groups_from_user(struct group_info *group_info,
1200     gid_t __user *grouplist)
1201 {
1202         int i;
1203         unsigned int count = group_info->ngroups;
1204
1205         for (i = 0; i < group_info->nblocks; i++) {
1206                 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1207                 unsigned int len = cp_count * sizeof(*grouplist);
1208
1209                 if (copy_from_user(group_info->blocks[i], grouplist, len))
1210                         return -EFAULT;
1211
1212                 grouplist += NGROUPS_PER_BLOCK;
1213                 count -= cp_count;
1214         }
1215         return 0;
1216 }
1217
1218 /* a simple Shell sort */
1219 static void groups_sort(struct group_info *group_info)
1220 {
1221         int base, max, stride;
1222         int gidsetsize = group_info->ngroups;
1223
1224         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1225                 ; /* nothing */
1226         stride /= 3;
1227
1228         while (stride) {
1229                 max = gidsetsize - stride;
1230                 for (base = 0; base < max; base++) {
1231                         int left = base;
1232                         int right = left + stride;
1233                         gid_t tmp = GROUP_AT(group_info, right);
1234
1235                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1236                                 GROUP_AT(group_info, right) =
1237                                     GROUP_AT(group_info, left);
1238                                 right = left;
1239                                 left -= stride;
1240                         }
1241                         GROUP_AT(group_info, right) = tmp;
1242                 }
1243                 stride /= 3;
1244         }
1245 }
1246
1247 /* a simple bsearch */
1248 int groups_search(const struct group_info *group_info, gid_t grp)
1249 {
1250         unsigned int left, right;
1251
1252         if (!group_info)
1253                 return 0;
1254
1255         left = 0;
1256         right = group_info->ngroups;
1257         while (left < right) {
1258                 unsigned int mid = (left+right)/2;
1259                 int cmp = grp - GROUP_AT(group_info, mid);
1260                 if (cmp > 0)
1261                         left = mid + 1;
1262                 else if (cmp < 0)
1263                         right = mid;
1264                 else
1265                         return 1;
1266         }
1267         return 0;
1268 }
1269
1270 /**
1271  * set_groups - Change a group subscription in a set of credentials
1272  * @new: The newly prepared set of credentials to alter
1273  * @group_info: The group list to install
1274  *
1275  * Validate a group subscription and, if valid, insert it into a set
1276  * of credentials.
1277  */
1278 int set_groups(struct cred *new, struct group_info *group_info)
1279 {
1280         int retval;
1281
1282         retval = security_task_setgroups(group_info);
1283         if (retval)
1284                 return retval;
1285
1286         put_group_info(new->group_info);
1287         groups_sort(group_info);
1288         get_group_info(group_info);
1289         new->group_info = group_info;
1290         return 0;
1291 }
1292
1293 EXPORT_SYMBOL(set_groups);
1294
1295 /**
1296  * set_current_groups - Change current's group subscription
1297  * @group_info: The group list to impose
1298  *
1299  * Validate a group subscription and, if valid, impose it upon current's task
1300  * security record.
1301  */
1302 int set_current_groups(struct group_info *group_info)
1303 {
1304         struct cred *new;
1305         int ret;
1306
1307         new = prepare_creds();
1308         if (!new)
1309                 return -ENOMEM;
1310
1311         ret = set_groups(new, group_info);
1312         if (ret < 0) {
1313                 abort_creds(new);
1314                 return ret;
1315         }
1316
1317         return commit_creds(new);
1318 }
1319
1320 EXPORT_SYMBOL(set_current_groups);
1321
1322 SYSCALL_DEFINE2(getgroups, int, gidsetsize, gid_t __user *, grouplist)
1323 {
1324         const struct cred *cred = current_cred();
1325         int i;
1326
1327         if (gidsetsize < 0)
1328                 return -EINVAL;
1329
1330         /* no need to grab task_lock here; it cannot change */
1331         i = cred->group_info->ngroups;
1332         if (gidsetsize) {
1333                 if (i > gidsetsize) {
1334                         i = -EINVAL;
1335                         goto out;
1336                 }
1337                 if (groups_to_user(grouplist, cred->group_info)) {
1338                         i = -EFAULT;
1339                         goto out;
1340                 }
1341         }
1342 out:
1343         return i;
1344 }
1345
1346 /*
1347  *      SMP: Our groups are copy-on-write. We can set them safely
1348  *      without another task interfering.
1349  */
1350
1351 SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
1352 {
1353         struct group_info *group_info;
1354         int retval;
1355
1356         if (!capable(CAP_SETGID))
1357                 return -EPERM;
1358         if ((unsigned)gidsetsize > NGROUPS_MAX)
1359                 return -EINVAL;
1360
1361         group_info = groups_alloc(gidsetsize);
1362         if (!group_info)
1363                 return -ENOMEM;
1364         retval = groups_from_user(group_info, grouplist);
1365         if (retval) {
1366                 put_group_info(group_info);
1367                 return retval;
1368         }
1369
1370         retval = set_current_groups(group_info);
1371         put_group_info(group_info);
1372
1373         return retval;
1374 }
1375
1376 /*
1377  * Check whether we're fsgid/egid or in the supplemental group..
1378  */
1379 int in_group_p(gid_t grp)
1380 {
1381         const struct cred *cred = current_cred();
1382         int retval = 1;
1383
1384         if (grp != cred->fsgid)
1385                 retval = groups_search(cred->group_info, grp);
1386         return retval;
1387 }
1388
1389 EXPORT_SYMBOL(in_group_p);
1390
1391 int in_egroup_p(gid_t grp)
1392 {
1393         const struct cred *cred = current_cred();
1394         int retval = 1;
1395
1396         if (grp != cred->egid)
1397                 retval = groups_search(cred->group_info, grp);
1398         return retval;
1399 }
1400
1401 EXPORT_SYMBOL(in_egroup_p);
1402
1403 DECLARE_RWSEM(uts_sem);
1404
1405 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1406 {
1407         int errno = 0;
1408
1409         down_read(&uts_sem);
1410         if (copy_to_user(name, utsname(), sizeof *name))
1411                 errno = -EFAULT;
1412         up_read(&uts_sem);
1413         return errno;
1414 }
1415
1416 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1417 {
1418         int errno;
1419         char tmp[__NEW_UTS_LEN];
1420
1421         if (!capable(CAP_SYS_ADMIN))
1422                 return -EPERM;
1423         if (len < 0 || len > __NEW_UTS_LEN)
1424                 return -EINVAL;
1425         down_write(&uts_sem);
1426         errno = -EFAULT;
1427         if (!copy_from_user(tmp, name, len)) {
1428                 struct new_utsname *u = utsname();
1429
1430                 memcpy(u->nodename, tmp, len);
1431                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1432                 errno = 0;
1433         }
1434         up_write(&uts_sem);
1435         return errno;
1436 }
1437
1438 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1439
1440 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1441 {
1442         int i, errno;
1443         struct new_utsname *u;
1444
1445         if (len < 0)
1446                 return -EINVAL;
1447         down_read(&uts_sem);
1448         u = utsname();
1449         i = 1 + strlen(u->nodename);
1450         if (i > len)
1451                 i = len;
1452         errno = 0;
1453         if (copy_to_user(name, u->nodename, i))
1454                 errno = -EFAULT;
1455         up_read(&uts_sem);
1456         return errno;
1457 }
1458
1459 #endif
1460
1461 /*
1462  * Only setdomainname; getdomainname can be implemented by calling
1463  * uname()
1464  */
1465 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1466 {
1467         int errno;
1468         char tmp[__NEW_UTS_LEN];
1469
1470         if (!capable(CAP_SYS_ADMIN))
1471                 return -EPERM;
1472         if (len < 0 || len > __NEW_UTS_LEN)
1473                 return -EINVAL;
1474
1475         down_write(&uts_sem);
1476         errno = -EFAULT;
1477         if (!copy_from_user(tmp, name, len)) {
1478                 struct new_utsname *u = utsname();
1479
1480                 memcpy(u->domainname, tmp, len);
1481                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1482                 errno = 0;
1483         }
1484         up_write(&uts_sem);
1485         return errno;
1486 }
1487
1488 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1489 {
1490         if (resource >= RLIM_NLIMITS)
1491                 return -EINVAL;
1492         else {
1493                 struct rlimit value;
1494                 task_lock(current->group_leader);
1495                 value = current->signal->rlim[resource];
1496                 task_unlock(current->group_leader);
1497                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1498         }
1499 }
1500
1501 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1502
1503 /*
1504  *      Back compatibility for getrlimit. Needed for some apps.
1505  */
1506
1507 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1508                 struct rlimit __user *, rlim)
1509 {
1510         struct rlimit x;
1511         if (resource >= RLIM_NLIMITS)
1512                 return -EINVAL;
1513
1514         task_lock(current->group_leader);
1515         x = current->signal->rlim[resource];
1516         task_unlock(current->group_leader);
1517         if (x.rlim_cur > 0x7FFFFFFF)
1518                 x.rlim_cur = 0x7FFFFFFF;
1519         if (x.rlim_max > 0x7FFFFFFF)
1520                 x.rlim_max = 0x7FFFFFFF;
1521         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1522 }
1523
1524 #endif
1525
1526 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1527 {
1528         struct rlimit new_rlim, *old_rlim;
1529         int retval;
1530
1531         if (resource >= RLIM_NLIMITS)
1532                 return -EINVAL;
1533         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1534                 return -EFAULT;
1535         if (new_rlim.rlim_cur > new_rlim.rlim_max)
1536                 return -EINVAL;
1537         old_rlim = current->signal->rlim + resource;
1538         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1539             !capable(CAP_SYS_RESOURCE))
1540                 return -EPERM;
1541         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1542                 return -EPERM;
1543
1544         retval = security_task_setrlimit(resource, &new_rlim);
1545         if (retval)
1546                 return retval;
1547
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         task_lock(current->group_leader);
1559         *old_rlim = new_rlim;
1560         task_unlock(current->group_leader);
1561
1562         if (resource != RLIMIT_CPU)
1563                 goto out;
1564
1565         /*
1566          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1567          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1568          * very long-standing error, and fixing it now risks breakage of
1569          * applications, so we live with it
1570          */
1571         if (new_rlim.rlim_cur == RLIM_INFINITY)
1572                 goto out;
1573
1574         update_rlimit_cpu(new_rlim.rlim_cur);
1575 out:
1576         return 0;
1577 }
1578
1579 /*
1580  * It would make sense to put struct rusage in the task_struct,
1581  * except that would make the task_struct be *really big*.  After
1582  * task_struct gets moved into malloc'ed memory, it would
1583  * make sense to do this.  It will make moving the rest of the information
1584  * a lot simpler!  (Which we're not doing right now because we're not
1585  * measuring them yet).
1586  *
1587  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1588  * races with threads incrementing their own counters.  But since word
1589  * reads are atomic, we either get new values or old values and we don't
1590  * care which for the sums.  We always take the siglock to protect reading
1591  * the c* fields from p->signal from races with exit.c updating those
1592  * fields when reaping, so a sample either gets all the additions of a
1593  * given child after it's reaped, or none so this sample is before reaping.
1594  *
1595  * Locking:
1596  * We need to take the siglock for CHILDEREN, SELF and BOTH
1597  * for  the cases current multithreaded, non-current single threaded
1598  * non-current multithreaded.  Thread traversal is now safe with
1599  * the siglock held.
1600  * Strictly speaking, we donot need to take the siglock if we are current and
1601  * single threaded,  as no one else can take our signal_struct away, no one
1602  * else can  reap the  children to update signal->c* counters, and no one else
1603  * can race with the signal-> fields. If we do not take any lock, the
1604  * signal-> fields could be read out of order while another thread was just
1605  * exiting. So we should  place a read memory barrier when we avoid the lock.
1606  * On the writer side,  write memory barrier is implied in  __exit_signal
1607  * as __exit_signal releases  the siglock spinlock after updating the signal->
1608  * fields. But we don't do this yet to keep things simple.
1609  *
1610  */
1611
1612 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1613 {
1614         r->ru_nvcsw += t->nvcsw;
1615         r->ru_nivcsw += t->nivcsw;
1616         r->ru_minflt += t->min_flt;
1617         r->ru_majflt += t->maj_flt;
1618         r->ru_inblock += task_io_get_inblock(t);
1619         r->ru_oublock += task_io_get_oublock(t);
1620 }
1621
1622 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1623 {
1624         struct task_struct *t;
1625         unsigned long flags;
1626         cputime_t utime, stime;
1627         struct task_cputime cputime;
1628
1629         memset((char *) r, 0, sizeof *r);
1630         utime = stime = cputime_zero;
1631
1632         if (who == RUSAGE_THREAD) {
1633                 utime = task_utime(current);
1634                 stime = task_stime(current);
1635                 accumulate_thread_rusage(p, r);
1636                 goto out;
1637         }
1638
1639         if (!lock_task_sighand(p, &flags))
1640                 return;
1641
1642         switch (who) {
1643                 case RUSAGE_BOTH:
1644                 case RUSAGE_CHILDREN:
1645                         utime = p->signal->cutime;
1646                         stime = p->signal->cstime;
1647                         r->ru_nvcsw = p->signal->cnvcsw;
1648                         r->ru_nivcsw = p->signal->cnivcsw;
1649                         r->ru_minflt = p->signal->cmin_flt;
1650                         r->ru_majflt = p->signal->cmaj_flt;
1651                         r->ru_inblock = p->signal->cinblock;
1652                         r->ru_oublock = p->signal->coublock;
1653
1654                         if (who == RUSAGE_CHILDREN)
1655                                 break;
1656
1657                 case RUSAGE_SELF:
1658                         thread_group_cputime(p, &cputime);
1659                         utime = cputime_add(utime, cputime.utime);
1660                         stime = cputime_add(stime, cputime.stime);
1661                         r->ru_nvcsw += p->signal->nvcsw;
1662                         r->ru_nivcsw += p->signal->nivcsw;
1663                         r->ru_minflt += p->signal->min_flt;
1664                         r->ru_majflt += p->signal->maj_flt;
1665                         r->ru_inblock += p->signal->inblock;
1666                         r->ru_oublock += p->signal->oublock;
1667                         t = p;
1668                         do {
1669                                 accumulate_thread_rusage(t, r);
1670                                 t = next_thread(t);
1671                         } while (t != p);
1672                         break;
1673
1674                 default:
1675                         BUG();
1676         }
1677         unlock_task_sighand(p, &flags);
1678
1679 out:
1680         cputime_to_timeval(utime, &r->ru_utime);
1681         cputime_to_timeval(stime, &r->ru_stime);
1682 }
1683
1684 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1685 {
1686         struct rusage r;
1687         k_getrusage(p, who, &r);
1688         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1689 }
1690
1691 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1692 {
1693         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1694             who != RUSAGE_THREAD)
1695                 return -EINVAL;
1696         return getrusage(current, who, ru);
1697 }
1698
1699 SYSCALL_DEFINE1(umask, int, mask)
1700 {
1701         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1702         return mask;
1703 }
1704
1705 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1706                 unsigned long, arg4, unsigned long, arg5)
1707 {
1708         struct task_struct *me = current;
1709         unsigned char comm[sizeof(me->comm)];
1710         long error;
1711
1712         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1713         if (error != -ENOSYS)
1714                 return error;
1715
1716         error = 0;
1717         switch (option) {
1718                 case PR_SET_PDEATHSIG:
1719                         if (!valid_signal(arg2)) {
1720                                 error = -EINVAL;
1721                                 break;
1722                         }
1723                         me->pdeath_signal = arg2;
1724                         error = 0;
1725                         break;
1726                 case PR_GET_PDEATHSIG:
1727                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1728                         break;
1729                 case PR_GET_DUMPABLE:
1730                         error = get_dumpable(me->mm);
1731                         break;
1732                 case PR_SET_DUMPABLE:
1733                         if (arg2 < 0 || arg2 > 1) {
1734                                 error = -EINVAL;
1735                                 break;
1736                         }
1737                         set_dumpable(me->mm, arg2);
1738                         error = 0;
1739                         break;
1740
1741                 case PR_SET_UNALIGN:
1742                         error = SET_UNALIGN_CTL(me, arg2);
1743                         break;
1744                 case PR_GET_UNALIGN:
1745                         error = GET_UNALIGN_CTL(me, arg2);
1746                         break;
1747                 case PR_SET_FPEMU:
1748                         error = SET_FPEMU_CTL(me, arg2);
1749                         break;
1750                 case PR_GET_FPEMU:
1751                         error = GET_FPEMU_CTL(me, arg2);
1752                         break;
1753                 case PR_SET_FPEXC:
1754                         error = SET_FPEXC_CTL(me, arg2);
1755                         break;
1756                 case PR_GET_FPEXC:
1757                         error = GET_FPEXC_CTL(me, arg2);
1758                         break;
1759                 case PR_GET_TIMING:
1760                         error = PR_TIMING_STATISTICAL;
1761                         break;
1762                 case PR_SET_TIMING:
1763                         if (arg2 != PR_TIMING_STATISTICAL)
1764                                 error = -EINVAL;
1765                         else
1766                                 error = 0;
1767                         break;
1768
1769                 case PR_SET_NAME:
1770                         comm[sizeof(me->comm)-1] = 0;
1771                         if (strncpy_from_user(comm, (char __user *)arg2,
1772                                               sizeof(me->comm) - 1) < 0)
1773                                 return -EFAULT;
1774                         set_task_comm(me, comm);
1775                         return 0;
1776                 case PR_GET_NAME:
1777                         get_task_comm(comm, me);
1778                         if (copy_to_user((char __user *)arg2, comm,
1779                                          sizeof(comm)))
1780                                 return -EFAULT;
1781                         return 0;
1782                 case PR_GET_ENDIAN:
1783                         error = GET_ENDIAN(me, arg2);
1784                         break;
1785                 case PR_SET_ENDIAN:
1786                         error = SET_ENDIAN(me, arg2);
1787                         break;
1788
1789                 case PR_GET_SECCOMP:
1790                         error = prctl_get_seccomp();
1791                         break;
1792                 case PR_SET_SECCOMP:
1793                         error = prctl_set_seccomp(arg2);
1794                         break;
1795                 case PR_GET_TSC:
1796                         error = GET_TSC_CTL(arg2);
1797                         break;
1798                 case PR_SET_TSC:
1799                         error = SET_TSC_CTL(arg2);
1800                         break;
1801                 case PR_GET_TIMERSLACK:
1802                         error = current->timer_slack_ns;
1803                         break;
1804                 case PR_SET_TIMERSLACK:
1805                         if (arg2 <= 0)
1806                                 current->timer_slack_ns =
1807                                         current->default_timer_slack_ns;
1808                         else
1809                                 current->timer_slack_ns = arg2;
1810                         error = 0;
1811                         break;
1812                 default:
1813                         error = -EINVAL;
1814                         break;
1815         }
1816         return error;
1817 }
1818
1819 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1820                 struct getcpu_cache __user *, unused)
1821 {
1822         int err = 0;
1823         int cpu = raw_smp_processor_id();
1824         if (cpup)
1825                 err |= put_user(cpu, cpup);
1826         if (nodep)
1827                 err |= put_user(cpu_to_node(cpu), nodep);
1828         return err ? -EFAULT : 0;
1829 }
1830
1831 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1832
1833 static void argv_cleanup(char **argv, char **envp)
1834 {
1835         argv_free(argv);
1836 }
1837
1838 /**
1839  * orderly_poweroff - Trigger an orderly system poweroff
1840  * @force: force poweroff if command execution fails
1841  *
1842  * This may be called from any context to trigger a system shutdown.
1843  * If the orderly shutdown fails, it will force an immediate shutdown.
1844  */
1845 int orderly_poweroff(bool force)
1846 {
1847         int argc;
1848         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1849         static char *envp[] = {
1850                 "HOME=/",
1851                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1852                 NULL
1853         };
1854         int ret = -ENOMEM;
1855         struct subprocess_info *info;
1856
1857         if (argv == NULL) {
1858                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1859                        __func__, poweroff_cmd);
1860                 goto out;
1861         }
1862
1863         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1864         if (info == NULL) {
1865                 argv_free(argv);
1866                 goto out;
1867         }
1868
1869         call_usermodehelper_setcleanup(info, argv_cleanup);
1870
1871         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1872
1873   out:
1874         if (ret && force) {
1875                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1876                        "forcing the issue\n");
1877
1878                 /* I guess this should try to kick off some daemon to
1879                    sync and poweroff asap.  Or not even bother syncing
1880                    if we're doing an emergency shutdown? */
1881                 emergency_sync();
1882                 kernel_power_off();
1883         }
1884
1885         return ret;
1886 }
1887 EXPORT_SYMBOL_GPL(orderly_poweroff);