kernel/sys.c

   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/notifier.h>
  12 #include <linux/reboot.h>
  13 #include <linux/prctl.h>
  14 #include <linux/highuid.h>
  15 #include <linux/fs.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/gfp.h>
  40 #include <linux/syscore_ops.h>
  41
  42 #include <linux/compat.h>
  43 #include <linux/syscalls.h>
  44 #include <linux/kprobes.h>
  45 #include <linux/user_namespace.h>
  46
  47 #include <linux/kmsg_dump.h>
  48
  49 #include <asm/uaccess.h>
  50 #include <asm/io.h>
  51 #include <asm/unistd.h>
  52
  53 #ifndef SET_UNALIGN_CTL
  54 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  55 #endif
  56 #ifndef GET_UNALIGN_CTL
  57 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  58 #endif
  59 #ifndef SET_FPEMU_CTL
  60 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  61 #endif
  62 #ifndef GET_FPEMU_CTL
  63 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  64 #endif
  65 #ifndef SET_FPEXC_CTL
  66 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  67 #endif
  68 #ifndef GET_FPEXC_CTL
  69 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  70 #endif
  71 #ifndef GET_ENDIAN
  72 # define GET_ENDIAN(a,b)        (-EINVAL)
  73 #endif
  74 #ifndef SET_ENDIAN
  75 # define SET_ENDIAN(a,b)        (-EINVAL)
  76 #endif
  77 #ifndef GET_TSC_CTL
  78 # define GET_TSC_CTL(a)         (-EINVAL)
  79 #endif
  80 #ifndef SET_TSC_CTL
  81 # define SET_TSC_CTL(a)         (-EINVAL)
  82 #endif
  83
  84 /*
  85  * this is where the system-wide overflow UID and GID are defined, for
  86  * architectures that now have 32-bit UID/GID but didn't in the past
  87  */
  88
  89 int overflowuid = DEFAULT_OVERFLOWUID;
  90 int overflowgid = DEFAULT_OVERFLOWGID;
  91
  92 #ifdef CONFIG_UID16
  93 EXPORT_SYMBOL(overflowuid);
  94 EXPORT_SYMBOL(overflowgid);
  95 #endif
  96
  97 /*
  98  * the same as above, but for filesystems which can only store a 16-bit
  99  * UID and GID. as such, this is needed on all architectures
 100  */
 101
 102 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
 103 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
 104
 105 EXPORT_SYMBOL(fs_overflowuid);
 106 EXPORT_SYMBOL(fs_overflowgid);
 107
 108 /*
 109  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
 110  */
 111
 112 int C_A_D = 1;
 113 struct pid *cad_pid;
 114 EXPORT_SYMBOL(cad_pid);
 115
 116 /*
 117  * If set, this is used for preparing the system to power off.
 118  */
 119
 120 void (*pm_power_off_prepare)(void);
 121
 122 /*
 123  * set the priority of a task
 124  * - the caller must hold the RCU read lock
 125  */
 126 static int set_one_prio(struct task_struct *p, int niceval, int error)
 127 {
 128         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 129         int no_nice;
 130
 131         if (pcred->uid  != cred->euid &&
 132             pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
 133                 error = -EPERM;
 134                 goto out;
 135         }
 136         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 137                 error = -EACCES;
 138                 goto out;
 139         }
 140         no_nice = security_task_setnice(p, niceval);
 141         if (no_nice) {
 142                 error = no_nice;
 143                 goto out;
 144         }
 145         if (error == -ESRCH)
 146                 error = 0;
 147         set_user_nice(p, niceval);
 148 out:
 149         return error;
 150 }
 151
 152 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 153 {
 154         struct task_struct *g, *p;
 155         struct user_struct *user;
 156         const struct cred *cred = current_cred();
 157         int error = -EINVAL;
 158         struct pid *pgrp;
 159
 160         if (which > PRIO_USER || which < PRIO_PROCESS)
 161                 goto out;
 162
 163         /* normalize: avoid signed division (rounding problems) */
 164         error = -ESRCH;
 165         if (niceval < -20)
 166                 niceval = -20;
 167         if (niceval > 19)
 168                 niceval = 19;
 169
 170         rcu_read_lock();
 171         read_lock(&tasklist_lock);
 172         switch (which) {
 173                 case PRIO_PROCESS:
 174                         if (who)
 175                                 p = find_task_by_vpid(who);
 176                         else
 177                                 p = current;
 178                         if (p)
 179                                 error = set_one_prio(p, niceval, error);
 180                         break;
 181                 case PRIO_PGRP:
 182                         if (who)
 183                                 pgrp = find_vpid(who);
 184                         else
 185                                 pgrp = task_pgrp(current);
 186                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 187                                 error = set_one_prio(p, niceval, error);
 188                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 189                         break;
 190                 case PRIO_USER:
 191                         user = (struct user_struct *) cred->user;
 192                         if (!who)
 193                                 who = cred->uid;
 194                         else if ((who != cred->uid) &&
 195                                  !(user = find_user(who)))
 196                                 goto out_unlock;        /* No processes for this user */
 197
 198                         do_each_thread(g, p) {
 199                                 if (__task_cred(p)->uid == who)
 200                                         error = set_one_prio(p, niceval, error);
 201                         } while_each_thread(g, p);
 202                         if (who != cred->uid)
 203                                 free_uid(user);         /* For find_user() */
 204                         break;
 205         }
 206 out_unlock:
 207         read_unlock(&tasklist_lock);
 208         rcu_read_unlock();
 209 out:
 210         return error;
 211 }
 212
 213 /*
 214  * Ugh. To avoid negative return values, "getpriority()" will
 215  * not return the normal nice-value, but a negated value that
 216  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 217  * to stay compatible.
 218  */
 219 SYSCALL_DEFINE2(getpriority, int, which, int, who)
 220 {
 221         struct task_struct *g, *p;
 222         struct user_struct *user;
 223         const struct cred *cred = current_cred();
 224         long niceval, retval = -ESRCH;
 225         struct pid *pgrp;
 226
 227         if (which > PRIO_USER || which < PRIO_PROCESS)
 228                 return -EINVAL;
 229
 230         rcu_read_lock();
 231         read_lock(&tasklist_lock);
 232         switch (which) {
 233                 case PRIO_PROCESS:
 234                         if (who)
 235                                 p = find_task_by_vpid(who);
 236                         else
 237                                 p = current;
 238                         if (p) {
 239                                 niceval = 20 - task_nice(p);
 240                                 if (niceval > retval)
 241                                         retval = niceval;
 242                         }
 243                         break;
 244                 case PRIO_PGRP:
 245                         if (who)
 246                                 pgrp = find_vpid(who);
 247                         else
 248                                 pgrp = task_pgrp(current);
 249                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 250                                 niceval = 20 - task_nice(p);
 251                                 if (niceval > retval)
 252                                         retval = niceval;
 253                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 254                         break;
 255                 case PRIO_USER:
 256                         user = (struct user_struct *) cred->user;
 257                         if (!who)
 258                                 who = cred->uid;
 259                         else if ((who != cred->uid) &&
 260                                  !(user = find_user(who)))
 261                                 goto out_unlock;        /* No processes for this user */
 262
 263                         do_each_thread(g, p) {
 264                                 if (__task_cred(p)->uid == who) {
 265                                         niceval = 20 - task_nice(p);
 266                                         if (niceval > retval)
 267                                                 retval = niceval;
 268                                 }
 269                         } while_each_thread(g, p);
 270                         if (who != cred->uid)
 271                                 free_uid(user);         /* for find_user() */
 272                         break;
 273         }
 274 out_unlock:
 275         read_unlock(&tasklist_lock);
 276         rcu_read_unlock();
 277
 278         return retval;
 279 }
 280
 281 /**
 282  *      emergency_restart - reboot the system
 283  *
 284  *      Without shutting down any hardware or taking any locks
 285  *      reboot the system.  This is called when we know we are in
 286  *      trouble so this is our best effort to reboot.  This is
 287  *      safe to call in interrupt context.
 288  */
 289 void emergency_restart(void)
 290 {
 291         kmsg_dump(KMSG_DUMP_EMERG);
 292         machine_emergency_restart();
 293 }
 294 EXPORT_SYMBOL_GPL(emergency_restart);
 295
 296 void kernel_restart_prepare(char *cmd)
 297 {
 298         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 299         system_state = SYSTEM_RESTART;
 300         device_shutdown();
 301         sysdev_shutdown();
 302         syscore_shutdown();
 303 }
 304
 305 /**
 306  *      kernel_restart - reboot the system
 307  *      @cmd: pointer to buffer containing command to execute for restart
 308  *              or %NULL
 309  *
 310  *      Shutdown everything and perform a clean reboot.
 311  *      This is not safe to call in interrupt context.
 312  */
 313 void kernel_restart(char *cmd)
 314 {
 315         kernel_restart_prepare(cmd);
 316         if (!cmd)
 317                 printk(KERN_EMERG "Restarting system.\n");
 318         else
 319                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 320         kmsg_dump(KMSG_DUMP_RESTART);
 321         machine_restart(cmd);
 322 }
 323 EXPORT_SYMBOL_GPL(kernel_restart);
 324
 325 static void kernel_shutdown_prepare(enum system_states state)
 326 {
 327         blocking_notifier_call_chain(&reboot_notifier_list,
 328                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 329         system_state = state;
 330         device_shutdown();
 331 }
 332 /**
 333  *      kernel_halt - halt the system
 334  *
 335  *      Shutdown everything and perform a clean system halt.
 336  */
 337 void kernel_halt(void)
 338 {
 339         kernel_shutdown_prepare(SYSTEM_HALT);
 340         sysdev_shutdown();
 341         syscore_shutdown();
 342         printk(KERN_EMERG "System halted.\n");
 343         kmsg_dump(KMSG_DUMP_HALT);
 344         machine_halt();
 345 }
 346
 347 EXPORT_SYMBOL_GPL(kernel_halt);
 348
 349 /**
 350  *      kernel_power_off - power_off the system
 351  *
 352  *      Shutdown everything and perform a clean system power_off.
 353  */
 354 void kernel_power_off(void)
 355 {
 356         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 357         if (pm_power_off_prepare)
 358                 pm_power_off_prepare();
 359         disable_nonboot_cpus();
 360         sysdev_shutdown();
 361         syscore_shutdown();
 362         printk(KERN_EMERG "Power down.\n");
 363         kmsg_dump(KMSG_DUMP_POWEROFF);
 364         machine_power_off();
 365 }
 366 EXPORT_SYMBOL_GPL(kernel_power_off);
 367
 368 static DEFINE_MUTEX(reboot_mutex);
 369
 370 /*
 371  * Reboot system call: for obvious reasons only root may call it,
 372  * and even root needs to set up some magic numbers in the registers
 373  * so that some mistake won't make this reboot the whole machine.
 374  * You can also set the meaning of the ctrl-alt-del-key here.
 375  *
 376  * reboot doesn't sync: do that yourself before calling this.
 377  */
 378 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 379                 void __user *, arg)
 380 {
 381         char buffer[256];
 382         int ret = 0;
 383
 384         /* We only trust the superuser with rebooting the system. */
 385         if (!capable(CAP_SYS_BOOT))
 386                 return -EPERM;
 387
 388         /* For safety, we require "magic" arguments. */
 389         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 390             (magic2 != LINUX_REBOOT_MAGIC2 &&
 391                         magic2 != LINUX_REBOOT_MAGIC2A &&
 392                         magic2 != LINUX_REBOOT_MAGIC2B &&
 393                         magic2 != LINUX_REBOOT_MAGIC2C))
 394                 return -EINVAL;
 395
 396         /* Instead of trying to make the power_off code look like
 397          * halt when pm_power_off is not set do it the easy way.
 398          */
 399         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 400                 cmd = LINUX_REBOOT_CMD_HALT;
 401
 402         mutex_lock(&reboot_mutex);
 403         switch (cmd) {
 404         case LINUX_REBOOT_CMD_RESTART:
 405                 kernel_restart(NULL);
 406                 break;
 407
 408         case LINUX_REBOOT_CMD_CAD_ON:
 409                 C_A_D = 1;
 410                 break;
 411
 412         case LINUX_REBOOT_CMD_CAD_OFF:
 413                 C_A_D = 0;
 414                 break;
 415
 416         case LINUX_REBOOT_CMD_HALT:
 417                 kernel_halt();
 418                 do_exit(0);
 419                 panic("cannot halt");
 420
 421         case LINUX_REBOOT_CMD_POWER_OFF:
 422                 kernel_power_off();
 423                 do_exit(0);
 424                 break;
 425
 426         case LINUX_REBOOT_CMD_RESTART2:
 427                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 428                         ret = -EFAULT;
 429                         break;
 430                 }
 431                 buffer[sizeof(buffer) - 1] = '\0';
 432
 433                 kernel_restart(buffer);
 434                 break;
 435
 436 #ifdef CONFIG_KEXEC
 437         case LINUX_REBOOT_CMD_KEXEC:
 438                 ret = kernel_kexec();
 439                 break;
 440 #endif
 441
 442 #ifdef CONFIG_HIBERNATION
 443         case LINUX_REBOOT_CMD_SW_SUSPEND:
 444                 ret = hibernate();
 445                 break;
 446 #endif
 447
 448         default:
 449                 ret = -EINVAL;
 450                 break;
 451         }
 452         mutex_unlock(&reboot_mutex);
 453         return ret;
 454 }
 455
 456 static void deferred_cad(struct work_struct *dummy)
 457 {
 458         kernel_restart(NULL);
 459 }
 460
 461 /*
 462  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 463  * As it's called within an interrupt, it may NOT sync: the only choice
 464  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 465  */
 466 void ctrl_alt_del(void)
 467 {
 468         static DECLARE_WORK(cad_work, deferred_cad);
 469
 470         if (C_A_D)
 471                 schedule_work(&cad_work);
 472         else
 473                 kill_cad_pid(SIGINT, 1);
 474 }
 475
 476 /*
 477  * Unprivileged users may change the real gid to the effective gid
 478  * or vice versa.  (BSD-style)
 479  *
 480  * If you set the real gid at all, or set the effective gid to a value not
 481  * equal to the real gid, then the saved gid is set to the new effective gid.
 482  *
 483  * This makes it possible for a setgid program to completely drop its
 484  * privileges, which is often a useful assertion to make when you are doing
 485  * a security audit over a program.
 486  *
 487  * The general idea is that a program which uses just setregid() will be
 488  * 100% compatible with BSD.  A program which uses just setgid() will be
 489  * 100% compatible with POSIX with saved IDs.
 490  *
 491  * SMP: There are not races, the GIDs are checked only by filesystem
 492  *      operations (as far as semantic preservation is concerned).
 493  */
 494 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 495 {
 496         const struct cred *old;
 497         struct cred *new;
 498         int retval;
 499
 500         new = prepare_creds();
 501         if (!new)
 502                 return -ENOMEM;
 503         old = current_cred();
 504
 505         retval = -EPERM;
 506         if (rgid != (gid_t) -1) {
 507                 if (old->gid == rgid ||
 508                     old->egid == rgid ||
 509                     capable(CAP_SETGID))
 510                         new->gid = rgid;
 511                 else
 512                         goto error;
 513         }
 514         if (egid != (gid_t) -1) {
 515                 if (old->gid == egid ||
 516                     old->egid == egid ||
 517                     old->sgid == egid ||
 518                     capable(CAP_SETGID))
 519                         new->egid = egid;
 520                 else
 521                         goto error;
 522         }
 523
 524         if (rgid != (gid_t) -1 ||
 525             (egid != (gid_t) -1 && egid != old->gid))
 526                 new->sgid = new->egid;
 527         new->fsgid = new->egid;
 528
 529         return commit_creds(new);
 530
 531 error:
 532         abort_creds(new);
 533         return retval;
 534 }
 535
 536 /*
 537  * setgid() is implemented like SysV w/ SAVED_IDS
 538  *
 539  * SMP: Same implicit races as above.
 540  */
 541 SYSCALL_DEFINE1(setgid, gid_t, gid)
 542 {
 543         const struct cred *old;
 544         struct cred *new;
 545         int retval;
 546
 547         new = prepare_creds();
 548         if (!new)
 549                 return -ENOMEM;
 550         old = current_cred();
 551
 552         retval = -EPERM;
 553         if (capable(CAP_SETGID))
 554                 new->gid = new->egid = new->sgid = new->fsgid = gid;
 555         else if (gid == old->gid || gid == old->sgid)
 556                 new->egid = new->fsgid = gid;
 557         else
 558                 goto error;
 559
 560         return commit_creds(new);
 561
 562 error:
 563         abort_creds(new);
 564         return retval;
 565 }
 566
 567 /*
 568  * change the user struct in a credentials set to match the new UID
 569  */
 570 static int set_user(struct cred *new)
 571 {
 572         struct user_struct *new_user;
 573
 574         new_user = alloc_uid(current_user_ns(), new->uid);
 575         if (!new_user)
 576                 return -EAGAIN;
 577
 578         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
 579                         new_user != INIT_USER) {
 580                 free_uid(new_user);
 581                 return -EAGAIN;
 582         }
 583
 584         free_uid(new->user);
 585         new->user = new_user;
 586         return 0;
 587 }
 588
 589 /*
 590  * Unprivileged users may change the real uid to the effective uid
 591  * or vice versa.  (BSD-style)
 592  *
 593  * If you set the real uid at all, or set the effective uid to a value not
 594  * equal to the real uid, then the saved uid is set to the new effective uid.
 595  *
 596  * This makes it possible for a setuid program to completely drop its
 597  * privileges, which is often a useful assertion to make when you are doing
 598  * a security audit over a program.
 599  *
 600  * The general idea is that a program which uses just setreuid() will be
 601  * 100% compatible with BSD.  A program which uses just setuid() will be
 602  * 100% compatible with POSIX with saved IDs.
 603  */
 604 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 605 {
 606         const struct cred *old;
 607         struct cred *new;
 608         int retval;
 609
 610         new = prepare_creds();
 611         if (!new)
 612                 return -ENOMEM;
 613         old = current_cred();
 614
 615         retval = -EPERM;
 616         if (ruid != (uid_t) -1) {
 617                 new->uid = ruid;
 618                 if (old->uid != ruid &&
 619                     old->euid != ruid &&
 620                     !capable(CAP_SETUID))
 621                         goto error;
 622         }
 623
 624         if (euid != (uid_t) -1) {
 625                 new->euid = euid;
 626                 if (old->uid != euid &&
 627                     old->euid != euid &&
 628                     old->suid != euid &&
 629                     !capable(CAP_SETUID))
 630                         goto error;
 631         }
 632
 633         if (new->uid != old->uid) {
 634                 retval = set_user(new);
 635                 if (retval < 0)
 636                         goto error;
 637         }
 638         if (ruid != (uid_t) -1 ||
 639             (euid != (uid_t) -1 && euid != old->uid))
 640                 new->suid = new->euid;
 641         new->fsuid = new->euid;
 642
 643         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 644         if (retval < 0)
 645                 goto error;
 646
 647         return commit_creds(new);
 648
 649 error:
 650         abort_creds(new);
 651         return retval;
 652 }
 653
 654 /*
 655  * setuid() is implemented like SysV with SAVED_IDS
 656  *
 657  * Note that SAVED_ID's is deficient in that a setuid root program
 658  * like sendmail, for example, cannot set its uid to be a normal
 659  * user and then switch back, because if you're root, setuid() sets
 660  * the saved uid too.  If you don't like this, blame the bright people
 661  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 662  * will allow a root program to temporarily drop privileges and be able to
 663  * regain them by swapping the real and effective uid.
 664  */
 665 SYSCALL_DEFINE1(setuid, uid_t, uid)
 666 {
 667         const struct cred *old;
 668         struct cred *new;
 669         int retval;
 670
 671         new = prepare_creds();
 672         if (!new)
 673                 return -ENOMEM;
 674         old = current_cred();
 675
 676         retval = -EPERM;
 677         if (capable(CAP_SETUID)) {
 678                 new->suid = new->uid = uid;
 679                 if (uid != old->uid) {
 680                         retval = set_user(new);
 681                         if (retval < 0)
 682                                 goto error;
 683                 }
 684         } else if (uid != old->uid && uid != new->suid) {
 685                 goto error;
 686         }
 687
 688         new->fsuid = new->euid = uid;
 689
 690         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 691         if (retval < 0)
 692                 goto error;
 693
 694         return commit_creds(new);
 695
 696 error:
 697         abort_creds(new);
 698         return retval;
 699 }
 700
 701
 702 /*
 703  * This function implements a generic ability to update ruid, euid,
 704  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 705  */
 706 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 707 {
 708         const struct cred *old;
 709         struct cred *new;
 710         int retval;
 711
 712         new = prepare_creds();
 713         if (!new)
 714                 return -ENOMEM;
 715
 716         old = current_cred();
 717
 718         retval = -EPERM;
 719         if (!capable(CAP_SETUID)) {
 720                 if (ruid != (uid_t) -1 && ruid != old->uid &&
 721                     ruid != old->euid  && ruid != old->suid)
 722                         goto error;
 723                 if (euid != (uid_t) -1 && euid != old->uid &&
 724                     euid != old->euid  && euid != old->suid)
 725                         goto error;
 726                 if (suid != (uid_t) -1 && suid != old->uid &&
 727                     suid != old->euid  && suid != old->suid)
 728                         goto error;
 729         }
 730
 731         if (ruid != (uid_t) -1) {
 732                 new->uid = ruid;
 733                 if (ruid != old->uid) {
 734                         retval = set_user(new);
 735                         if (retval < 0)
 736                                 goto error;
 737                 }
 738         }
 739         if (euid != (uid_t) -1)
 740                 new->euid = euid;
 741         if (suid != (uid_t) -1)
 742                 new->suid = suid;
 743         new->fsuid = new->euid;
 744
 745         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 746         if (retval < 0)
 747                 goto error;
 748
 749         return commit_creds(new);
 750
 751 error:
 752         abort_creds(new);
 753         return retval;
 754 }
 755
 756 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
 757 {
 758         const struct cred *cred = current_cred();
 759         int retval;
 760
 761         if (!(retval   = put_user(cred->uid,  ruid)) &&
 762             !(retval   = put_user(cred->euid, euid)))
 763                 retval = put_user(cred->suid, suid);
 764
 765         return retval;
 766 }
 767
 768 /*
 769  * Same as above, but for rgid, egid, sgid.
 770  */
 771 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 772 {
 773         const struct cred *old;
 774         struct cred *new;
 775         int retval;
 776
 777         new = prepare_creds();
 778         if (!new)
 779                 return -ENOMEM;
 780         old = current_cred();
 781
 782         retval = -EPERM;
 783         if (!capable(CAP_SETGID)) {
 784                 if (rgid != (gid_t) -1 && rgid != old->gid &&
 785                     rgid != old->egid  && rgid != old->sgid)
 786                         goto error;
 787                 if (egid != (gid_t) -1 && egid != old->gid &&
 788                     egid != old->egid  && egid != old->sgid)
 789                         goto error;
 790                 if (sgid != (gid_t) -1 && sgid != old->gid &&
 791                     sgid != old->egid  && sgid != old->sgid)
 792                         goto error;
 793         }
 794
 795         if (rgid != (gid_t) -1)
 796                 new->gid = rgid;
 797         if (egid != (gid_t) -1)
 798                 new->egid = egid;
 799         if (sgid != (gid_t) -1)
 800                 new->sgid = sgid;
 801         new->fsgid = new->egid;
 802
 803         return commit_creds(new);
 804
 805 error:
 806         abort_creds(new);
 807         return retval;
 808 }
 809
 810 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
 811 {
 812         const struct cred *cred = current_cred();
 813         int retval;
 814
 815         if (!(retval   = put_user(cred->gid,  rgid)) &&
 816             !(retval   = put_user(cred->egid, egid)))
 817                 retval = put_user(cred->sgid, sgid);
 818
 819         return retval;
 820 }
 821
 822
 823 /*
 824  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 825  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 826  * whatever uid it wants to). It normally shadows "euid", except when
 827  * explicitly set by setfsuid() or for access..
 828  */
 829 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 830 {
 831         const struct cred *old;
 832         struct cred *new;
 833         uid_t old_fsuid;
 834
 835         new = prepare_creds();
 836         if (!new)
 837                 return current_fsuid();
 838         old = current_cred();
 839         old_fsuid = old->fsuid;
 840
 841         if (uid == old->uid  || uid == old->euid  ||
 842             uid == old->suid || uid == old->fsuid ||
 843             capable(CAP_SETUID)) {
 844                 if (uid != old_fsuid) {
 845                         new->fsuid = uid;
 846                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 847                                 goto change_okay;
 848                 }
 849         }
 850
 851         abort_creds(new);
 852         return old_fsuid;
 853
 854 change_okay:
 855         commit_creds(new);
 856         return old_fsuid;
 857 }
 858
 859 /*
 860  * Samma på svenska..
 861  */
 862 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
 863 {
 864         const struct cred *old;
 865         struct cred *new;
 866         gid_t old_fsgid;
 867
 868         new = prepare_creds();
 869         if (!new)
 870                 return current_fsgid();
 871         old = current_cred();
 872         old_fsgid = old->fsgid;
 873
 874         if (gid == old->gid  || gid == old->egid  ||
 875             gid == old->sgid || gid == old->fsgid ||
 876             capable(CAP_SETGID)) {
 877                 if (gid != old_fsgid) {
 878                         new->fsgid = gid;
 879                         goto change_okay;
 880                 }
 881         }
 882
 883         abort_creds(new);
 884         return old_fsgid;
 885
 886 change_okay:
 887         commit_creds(new);
 888         return old_fsgid;
 889 }
 890
 891 void do_sys_times(struct tms *tms)
 892 {
 893         cputime_t tgutime, tgstime, cutime, cstime;
 894
 895         spin_lock_irq(&current->sighand->siglock);
 896         thread_group_times(current, &tgutime, &tgstime);
 897         cutime = current->signal->cutime;
 898         cstime = current->signal->cstime;
 899         spin_unlock_irq(&current->sighand->siglock);
 900         tms->tms_utime = cputime_to_clock_t(tgutime);
 901         tms->tms_stime = cputime_to_clock_t(tgstime);
 902         tms->tms_cutime = cputime_to_clock_t(cutime);
 903         tms->tms_cstime = cputime_to_clock_t(cstime);
 904 }
 905
 906 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
 907 {
 908         if (tbuf) {
 909                 struct tms tmp;
 910
 911                 do_sys_times(&tmp);
 912                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 913                         return -EFAULT;
 914         }
 915         force_successful_syscall_return();
 916         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 917 }
 918
 919 /*
 920  * This needs some heavy checking ...
 921  * I just haven't the stomach for it. I also don't fully
 922  * understand sessions/pgrp etc. Let somebody who does explain it.
 923  *
 924  * OK, I think I have the protection semantics right.... this is really
 925  * only important on a multi-user system anyway, to make sure one user
 926  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 927  *
 928  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 929  * LBT 04.03.94
 930  */
 931 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
 932 {
 933         struct task_struct *p;
 934         struct task_struct *group_leader = current->group_leader;
 935         struct pid *pgrp;
 936         int err;
 937
 938         if (!pid)
 939                 pid = task_pid_vnr(group_leader);
 940         if (!pgid)
 941                 pgid = pid;
 942         if (pgid < 0)
 943                 return -EINVAL;
 944         rcu_read_lock();
 945
 946         /* From this point forward we keep holding onto the tasklist lock
 947          * so that our parent does not change from under us. -DaveM
 948          */
 949         write_lock_irq(&tasklist_lock);
 950
 951         err = -ESRCH;
 952         p = find_task_by_vpid(pid);
 953         if (!p)
 954                 goto out;
 955
 956         err = -EINVAL;
 957         if (!thread_group_leader(p))
 958                 goto out;
 959
 960         if (same_thread_group(p->real_parent, group_leader)) {
 961                 err = -EPERM;
 962                 if (task_session(p) != task_session(group_leader))
 963                         goto out;
 964                 err = -EACCES;
 965                 if (p->did_exec)
 966                         goto out;
 967         } else {
 968                 err = -ESRCH;
 969                 if (p != group_leader)
 970                         goto out;
 971         }
 972
 973         err = -EPERM;
 974         if (p->signal->leader)
 975                 goto out;
 976
 977         pgrp = task_pid(p);
 978         if (pgid != pid) {
 979                 struct task_struct *g;
 980
 981                 pgrp = find_vpid(pgid);
 982                 g = pid_task(pgrp, PIDTYPE_PGID);
 983                 if (!g || task_session(g) != task_session(group_leader))
 984                         goto out;
 985         }
 986
 987         err = security_task_setpgid(p, pgid);
 988         if (err)
 989                 goto out;
 990
 991         if (task_pgrp(p) != pgrp)
 992                 change_pid(p, PIDTYPE_PGID, pgrp);
 993
 994         err = 0;
 995 out:
 996         /* All paths lead to here, thus we are safe. -DaveM */
 997         write_unlock_irq(&tasklist_lock);
 998         rcu_read_unlock();
 999         return err;
1000 }
1001
1002 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1003 {
1004         struct task_struct *p;
1005         struct pid *grp;
1006         int retval;
1007
1008         rcu_read_lock();
1009         if (!pid)
1010                 grp = task_pgrp(current);
1011         else {
1012                 retval = -ESRCH;
1013                 p = find_task_by_vpid(pid);
1014                 if (!p)
1015                         goto out;
1016                 grp = task_pgrp(p);
1017                 if (!grp)
1018                         goto out;
1019
1020                 retval = security_task_getpgid(p);
1021                 if (retval)
1022                         goto out;
1023         }
1024         retval = pid_vnr(grp);
1025 out:
1026         rcu_read_unlock();
1027         return retval;
1028 }
1029
1030 #ifdef __ARCH_WANT_SYS_GETPGRP
1031
1032 SYSCALL_DEFINE0(getpgrp)
1033 {
1034         return sys_getpgid(0);
1035 }
1036
1037 #endif
1038
1039 SYSCALL_DEFINE1(getsid, pid_t, pid)
1040 {
1041         struct task_struct *p;
1042         struct pid *sid;
1043         int retval;
1044
1045         rcu_read_lock();
1046         if (!pid)
1047                 sid = task_session(current);
1048         else {
1049                 retval = -ESRCH;
1050                 p = find_task_by_vpid(pid);
1051                 if (!p)
1052                         goto out;
1053                 sid = task_session(p);
1054                 if (!sid)
1055                         goto out;
1056
1057                 retval = security_task_getsid(p);
1058                 if (retval)
1059                         goto out;
1060         }
1061         retval = pid_vnr(sid);
1062 out:
1063         rcu_read_unlock();
1064         return retval;
1065 }
1066
1067 SYSCALL_DEFINE0(setsid)
1068 {
1069         struct task_struct *group_leader = current->group_leader;
1070         struct pid *sid = task_pid(group_leader);
1071         pid_t session = pid_vnr(sid);
1072         int err = -EPERM;
1073
1074         write_lock_irq(&tasklist_lock);
1075         /* Fail if I am already a session leader */
1076         if (group_leader->signal->leader)
1077                 goto out;
1078
1079         /* Fail if a process group id already exists that equals the
1080          * proposed session id.
1081          */
1082         if (pid_task(sid, PIDTYPE_PGID))
1083                 goto out;
1084
1085         group_leader->signal->leader = 1;
1086         __set_special_pids(sid);
1087
1088         proc_clear_tty(group_leader);
1089
1090         err = session;
1091 out:
1092         write_unlock_irq(&tasklist_lock);
1093         if (err > 0) {
1094                 proc_sid_connector(group_leader);
1095                 sched_autogroup_create_attach(group_leader);
1096         }
1097         return err;
1098 }
1099
1100 DECLARE_RWSEM(uts_sem);
1101
1102 #ifdef COMPAT_UTS_MACHINE
1103 #define override_architecture(name) \
1104         (personality(current->personality) == PER_LINUX32 && \
1105          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1106                       sizeof(COMPAT_UTS_MACHINE)))
1107 #else
1108 #define override_architecture(name)     0
1109 #endif
1110
1111 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1112 {
1113         int errno = 0;
1114
1115         down_read(&uts_sem);
1116         if (copy_to_user(name, utsname(), sizeof *name))
1117                 errno = -EFAULT;
1118         up_read(&uts_sem);
1119
1120         if (!errno && override_architecture(name))
1121                 errno = -EFAULT;
1122         return errno;
1123 }
1124
1125 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1126 /*
1127  * Old cruft
1128  */
1129 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1130 {
1131         int error = 0;
1132
1133         if (!name)
1134                 return -EFAULT;
1135
1136         down_read(&uts_sem);
1137         if (copy_to_user(name, utsname(), sizeof(*name)))
1138                 error = -EFAULT;
1139         up_read(&uts_sem);
1140
1141         if (!error && override_architecture(name))
1142                 error = -EFAULT;
1143         return error;
1144 }
1145
1146 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1147 {
1148         int error;
1149
1150         if (!name)
1151                 return -EFAULT;
1152         if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
1153                 return -EFAULT;
1154
1155         down_read(&uts_sem);
1156         error = __copy_to_user(&name->sysname, &utsname()->sysname,
1157                                __OLD_UTS_LEN);
1158         error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
1159         error |= __copy_to_user(&name->nodename, &utsname()->nodename,
1160                                 __OLD_UTS_LEN);
1161         error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
1162         error |= __copy_to_user(&name->release, &utsname()->release,
1163                                 __OLD_UTS_LEN);
1164         error |= __put_user(0, name->release + __OLD_UTS_LEN);
1165         error |= __copy_to_user(&name->version, &utsname()->version,
1166                                 __OLD_UTS_LEN);
1167         error |= __put_user(0, name->version + __OLD_UTS_LEN);
1168         error |= __copy_to_user(&name->machine, &utsname()->machine,
1169                                 __OLD_UTS_LEN);
1170         error |= __put_user(0, name->machine + __OLD_UTS_LEN);
1171         up_read(&uts_sem);
1172
1173         if (!error && override_architecture(name))
1174                 error = -EFAULT;
1175         return error ? -EFAULT : 0;
1176 }
1177 #endif
1178
1179 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1180 {
1181         int errno;
1182         char tmp[__NEW_UTS_LEN];
1183
1184         if (!capable(CAP_SYS_ADMIN))
1185                 return -EPERM;
1186         if (len < 0 || len > __NEW_UTS_LEN)
1187                 return -EINVAL;
1188         down_write(&uts_sem);
1189         errno = -EFAULT;
1190         if (!copy_from_user(tmp, name, len)) {
1191                 struct new_utsname *u = utsname();
1192
1193                 memcpy(u->nodename, tmp, len);
1194                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1195                 errno = 0;
1196         }
1197         up_write(&uts_sem);
1198         return errno;
1199 }
1200
1201 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1202
1203 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1204 {
1205         int i, errno;
1206         struct new_utsname *u;
1207
1208         if (len < 0)
1209                 return -EINVAL;
1210         down_read(&uts_sem);
1211         u = utsname();
1212         i = 1 + strlen(u->nodename);
1213         if (i > len)
1214                 i = len;
1215         errno = 0;
1216         if (copy_to_user(name, u->nodename, i))
1217                 errno = -EFAULT;
1218         up_read(&uts_sem);
1219         return errno;
1220 }
1221
1222 #endif
1223
1224 /*
1225  * Only setdomainname; getdomainname can be implemented by calling
1226  * uname()
1227  */
1228 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1229 {
1230         int errno;
1231         char tmp[__NEW_UTS_LEN];
1232
1233         if (!capable(CAP_SYS_ADMIN))
1234                 return -EPERM;
1235         if (len < 0 || len > __NEW_UTS_LEN)
1236                 return -EINVAL;
1237
1238         down_write(&uts_sem);
1239         errno = -EFAULT;
1240         if (!copy_from_user(tmp, name, len)) {
1241                 struct new_utsname *u = utsname();
1242
1243                 memcpy(u->domainname, tmp, len);
1244                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1245                 errno = 0;
1246         }
1247         up_write(&uts_sem);
1248         return errno;
1249 }
1250
1251 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1252 {
1253         struct rlimit value;
1254         int ret;
1255
1256         ret = do_prlimit(current, resource, NULL, &value);
1257         if (!ret)
1258                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1259
1260         return ret;
1261 }
1262
1263 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1264
1265 /*
1266  *      Back compatibility for getrlimit. Needed for some apps.
1267  */
1268
1269 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1270                 struct rlimit __user *, rlim)
1271 {
1272         struct rlimit x;
1273         if (resource >= RLIM_NLIMITS)
1274                 return -EINVAL;
1275
1276         task_lock(current->group_leader);
1277         x = current->signal->rlim[resource];
1278         task_unlock(current->group_leader);
1279         if (x.rlim_cur > 0x7FFFFFFF)
1280                 x.rlim_cur = 0x7FFFFFFF;
1281         if (x.rlim_max > 0x7FFFFFFF)
1282                 x.rlim_max = 0x7FFFFFFF;
1283         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1284 }
1285
1286 #endif
1287
1288 static inline bool rlim64_is_infinity(__u64 rlim64)
1289 {
1290 #if BITS_PER_LONG < 64
1291         return rlim64 >= ULONG_MAX;
1292 #else
1293         return rlim64 == RLIM64_INFINITY;
1294 #endif
1295 }
1296
1297 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1298 {
1299         if (rlim->rlim_cur == RLIM_INFINITY)
1300                 rlim64->rlim_cur = RLIM64_INFINITY;
1301         else
1302                 rlim64->rlim_cur = rlim->rlim_cur;
1303         if (rlim->rlim_max == RLIM_INFINITY)
1304                 rlim64->rlim_max = RLIM64_INFINITY;
1305         else
1306                 rlim64->rlim_max = rlim->rlim_max;
1307 }
1308
1309 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1310 {
1311         if (rlim64_is_infinity(rlim64->rlim_cur))
1312                 rlim->rlim_cur = RLIM_INFINITY;
1313         else
1314                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1315         if (rlim64_is_infinity(rlim64->rlim_max))
1316                 rlim->rlim_max = RLIM_INFINITY;
1317         else
1318                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1319 }
1320
1321 /* make sure you are allowed to change @tsk limits before calling this */
1322 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1323                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1324 {
1325         struct rlimit *rlim;
1326         int retval = 0;
1327
1328         if (resource >= RLIM_NLIMITS)
1329                 return -EINVAL;
1330         if (new_rlim) {
1331                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1332                         return -EINVAL;
1333                 if (resource == RLIMIT_NOFILE &&
1334                                 new_rlim->rlim_max > sysctl_nr_open)
1335                         return -EPERM;
1336         }
1337
1338         /* protect tsk->signal and tsk->sighand from disappearing */
1339         read_lock(&tasklist_lock);
1340         if (!tsk->sighand) {
1341                 retval = -ESRCH;
1342                 goto out;
1343         }
1344
1345         rlim = tsk->signal->rlim + resource;
1346         task_lock(tsk->group_leader);
1347         if (new_rlim) {
1348                 if (new_rlim->rlim_max > rlim->rlim_max &&
1349                                 !capable(CAP_SYS_RESOURCE))
1350                         retval = -EPERM;
1351                 if (!retval)
1352                         retval = security_task_setrlimit(tsk->group_leader,
1353                                         resource, new_rlim);
1354                 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) {
1355                         /*
1356                          * The caller is asking for an immediate RLIMIT_CPU
1357                          * expiry.  But we use the zero value to mean "it was
1358                          * never set".  So let's cheat and make it one second
1359                          * instead
1360                          */
1361                         new_rlim->rlim_cur = 1;
1362                 }
1363         }
1364         if (!retval) {
1365                 if (old_rlim)
1366                         *old_rlim = *rlim;
1367                 if (new_rlim)
1368                         *rlim = *new_rlim;
1369         }
1370         task_unlock(tsk->group_leader);
1371
1372         /*
1373          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1374          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1375          * very long-standing error, and fixing it now risks breakage of
1376          * applications, so we live with it
1377          */
1378          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1379                          new_rlim->rlim_cur != RLIM_INFINITY)
1380                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1381 out:
1382         read_unlock(&tasklist_lock);
1383         return retval;
1384 }
1385
1386 /* rcu lock must be held */
1387 static int check_prlimit_permission(struct task_struct *task)
1388 {
1389         const struct cred *cred = current_cred(), *tcred;
1390
1391         tcred = __task_cred(task);
1392         if (current != task &&
1393             (cred->uid != tcred->euid ||
1394              cred->uid != tcred->suid ||
1395              cred->uid != tcred->uid  ||
1396              cred->gid != tcred->egid ||
1397              cred->gid != tcred->sgid ||
1398              cred->gid != tcred->gid) &&
1399              !capable(CAP_SYS_RESOURCE)) {
1400                 return -EPERM;
1401         }
1402
1403         return 0;
1404 }
1405
1406 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1407                 const struct rlimit64 __user *, new_rlim,
1408                 struct rlimit64 __user *, old_rlim)
1409 {
1410         struct rlimit64 old64, new64;
1411         struct rlimit old, new;
1412         struct task_struct *tsk;
1413         int ret;
1414
1415         if (new_rlim) {
1416                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1417                         return -EFAULT;
1418                 rlim64_to_rlim(&new64, &new);
1419         }
1420
1421         rcu_read_lock();
1422         tsk = pid ? find_task_by_vpid(pid) : current;
1423         if (!tsk) {
1424                 rcu_read_unlock();
1425                 return -ESRCH;
1426         }
1427         ret = check_prlimit_permission(tsk);
1428         if (ret) {
1429                 rcu_read_unlock();
1430                 return ret;
1431         }
1432         get_task_struct(tsk);
1433         rcu_read_unlock();
1434
1435         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1436                         old_rlim ? &old : NULL);
1437
1438         if (!ret && old_rlim) {
1439                 rlim_to_rlim64(&old, &old64);
1440                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1441                         ret = -EFAULT;
1442         }
1443
1444         put_task_struct(tsk);
1445         return ret;
1446 }
1447
1448 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1449 {
1450         struct rlimit new_rlim;
1451
1452         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1453                 return -EFAULT;
1454         return do_prlimit(current, resource, &new_rlim, NULL);
1455 }
1456
1457 /*
1458  * It would make sense to put struct rusage in the task_struct,
1459  * except that would make the task_struct be *really big*.  After
1460  * task_struct gets moved into malloc'ed memory, it would
1461  * make sense to do this.  It will make moving the rest of the information
1462  * a lot simpler!  (Which we're not doing right now because we're not
1463  * measuring them yet).
1464  *
1465  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1466  * races with threads incrementing their own counters.  But since word
1467  * reads are atomic, we either get new values or old values and we don't
1468  * care which for the sums.  We always take the siglock to protect reading
1469  * the c* fields from p->signal from races with exit.c updating those
1470  * fields when reaping, so a sample either gets all the additions of a
1471  * given child after it's reaped, or none so this sample is before reaping.
1472  *
1473  * Locking:
1474  * We need to take the siglock for CHILDEREN, SELF and BOTH
1475  * for  the cases current multithreaded, non-current single threaded
1476  * non-current multithreaded.  Thread traversal is now safe with
1477  * the siglock held.
1478  * Strictly speaking, we donot need to take the siglock if we are current and
1479  * single threaded,  as no one else can take our signal_struct away, no one
1480  * else can  reap the  children to update signal->c* counters, and no one else
1481  * can race with the signal-> fields. If we do not take any lock, the
1482  * signal-> fields could be read out of order while another thread was just
1483  * exiting. So we should  place a read memory barrier when we avoid the lock.
1484  * On the writer side,  write memory barrier is implied in  __exit_signal
1485  * as __exit_signal releases  the siglock spinlock after updating the signal->
1486  * fields. But we don't do this yet to keep things simple.
1487  *
1488  */
1489
1490 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1491 {
1492         r->ru_nvcsw += t->nvcsw;
1493         r->ru_nivcsw += t->nivcsw;
1494         r->ru_minflt += t->min_flt;
1495         r->ru_majflt += t->maj_flt;
1496         r->ru_inblock += task_io_get_inblock(t);
1497         r->ru_oublock += task_io_get_oublock(t);
1498 }
1499
1500 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1501 {
1502         struct task_struct *t;
1503         unsigned long flags;
1504         cputime_t tgutime, tgstime, utime, stime;
1505         unsigned long maxrss = 0;
1506
1507         memset((char *) r, 0, sizeof *r);
1508         utime = stime = cputime_zero;
1509
1510         if (who == RUSAGE_THREAD) {
1511                 task_times(current, &utime, &stime);
1512                 accumulate_thread_rusage(p, r);
1513                 maxrss = p->signal->maxrss;
1514                 goto out;
1515         }
1516
1517         if (!lock_task_sighand(p, &flags))
1518                 return;
1519
1520         switch (who) {
1521                 case RUSAGE_BOTH:
1522                 case RUSAGE_CHILDREN:
1523                         utime = p->signal->cutime;
1524                         stime = p->signal->cstime;
1525                         r->ru_nvcsw = p->signal->cnvcsw;
1526                         r->ru_nivcsw = p->signal->cnivcsw;
1527                         r->ru_minflt = p->signal->cmin_flt;
1528                         r->ru_majflt = p->signal->cmaj_flt;
1529                         r->ru_inblock = p->signal->cinblock;
1530                         r->ru_oublock = p->signal->coublock;
1531                         maxrss = p->signal->cmaxrss;
1532
1533                         if (who == RUSAGE_CHILDREN)
1534                                 break;
1535
1536                 case RUSAGE_SELF:
1537                         thread_group_times(p, &tgutime, &tgstime);
1538                         utime = cputime_add(utime, tgutime);
1539                         stime = cputime_add(stime, tgstime);
1540                         r->ru_nvcsw += p->signal->nvcsw;
1541                         r->ru_nivcsw += p->signal->nivcsw;
1542                         r->ru_minflt += p->signal->min_flt;
1543                         r->ru_majflt += p->signal->maj_flt;
1544                         r->ru_inblock += p->signal->inblock;
1545                         r->ru_oublock += p->signal->oublock;
1546                         if (maxrss < p->signal->maxrss)
1547                                 maxrss = p->signal->maxrss;
1548                         t = p;
1549                         do {
1550                                 accumulate_thread_rusage(t, r);
1551                                 t = next_thread(t);
1552                         } while (t != p);
1553                         break;
1554
1555                 default:
1556                         BUG();
1557         }
1558         unlock_task_sighand(p, &flags);
1559
1560 out:
1561         cputime_to_timeval(utime, &r->ru_utime);
1562         cputime_to_timeval(stime, &r->ru_stime);
1563
1564         if (who != RUSAGE_CHILDREN) {
1565                 struct mm_struct *mm = get_task_mm(p);
1566                 if (mm) {
1567                         setmax_mm_hiwater_rss(&maxrss, mm);
1568                         mmput(mm);
1569                 }
1570         }
1571         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1572 }
1573
1574 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1575 {
1576         struct rusage r;
1577         k_getrusage(p, who, &r);
1578         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1579 }
1580
1581 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1582 {
1583         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1584             who != RUSAGE_THREAD)
1585                 return -EINVAL;
1586         return getrusage(current, who, ru);
1587 }
1588
1589 SYSCALL_DEFINE1(umask, int, mask)
1590 {
1591         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1592         return mask;
1593 }
1594
1595 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
1596                 unsigned long, arg4, unsigned long, arg5)
1597 {
1598         struct task_struct *me = current;
1599         unsigned char comm[sizeof(me->comm)];
1600         long error;
1601
1602         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1603         if (error != -ENOSYS)
1604                 return error;
1605
1606         error = 0;
1607         switch (option) {
1608                 case PR_SET_PDEATHSIG:
1609                         if (!valid_signal(arg2)) {
1610                                 error = -EINVAL;
1611                                 break;
1612                         }
1613                         me->pdeath_signal = arg2;
1614                         error = 0;
1615                         break;
1616                 case PR_GET_PDEATHSIG:
1617                         error = put_user(me->pdeath_signal, (int __user *)arg2);
1618                         break;
1619                 case PR_GET_DUMPABLE:
1620                         error = get_dumpable(me->mm);
1621                         break;
1622                 case PR_SET_DUMPABLE:
1623                         if (arg2 < 0 || arg2 > 1) {
1624                                 error = -EINVAL;
1625                                 break;
1626                         }
1627                         set_dumpable(me->mm, arg2);
1628                         error = 0;
1629                         break;
1630
1631                 case PR_SET_UNALIGN:
1632                         error = SET_UNALIGN_CTL(me, arg2);
1633                         break;
1634                 case PR_GET_UNALIGN:
1635                         error = GET_UNALIGN_CTL(me, arg2);
1636                         break;
1637                 case PR_SET_FPEMU:
1638                         error = SET_FPEMU_CTL(me, arg2);
1639                         break;
1640                 case PR_GET_FPEMU:
1641                         error = GET_FPEMU_CTL(me, arg2);
1642                         break;
1643                 case PR_SET_FPEXC:
1644                         error = SET_FPEXC_CTL(me, arg2);
1645                         break;
1646                 case PR_GET_FPEXC:
1647                         error = GET_FPEXC_CTL(me, arg2);
1648                         break;
1649                 case PR_GET_TIMING:
1650                         error = PR_TIMING_STATISTICAL;
1651                         break;
1652                 case PR_SET_TIMING:
1653                         if (arg2 != PR_TIMING_STATISTICAL)
1654                                 error = -EINVAL;
1655                         else
1656                                 error = 0;
1657                         break;
1658
1659                 case PR_SET_NAME:
1660                         comm[sizeof(me->comm)-1] = 0;
1661                         if (strncpy_from_user(comm, (char __user *)arg2,
1662                                               sizeof(me->comm) - 1) < 0)
1663                                 return -EFAULT;
1664                         set_task_comm(me, comm);
1665                         return 0;
1666                 case PR_GET_NAME:
1667                         get_task_comm(comm, me);
1668                         if (copy_to_user((char __user *)arg2, comm,
1669                                          sizeof(comm)))
1670                                 return -EFAULT;
1671                         return 0;
1672                 case PR_GET_ENDIAN:
1673                         error = GET_ENDIAN(me, arg2);
1674                         break;
1675                 case PR_SET_ENDIAN:
1676                         error = SET_ENDIAN(me, arg2);
1677                         break;
1678
1679                 case PR_GET_SECCOMP:
1680                         error = prctl_get_seccomp();
1681                         break;
1682                 case PR_SET_SECCOMP:
1683                         error = prctl_set_seccomp(arg2);
1684                         break;
1685                 case PR_GET_TSC:
1686                         error = GET_TSC_CTL(arg2);
1687                         break;
1688                 case PR_SET_TSC:
1689                         error = SET_TSC_CTL(arg2);
1690                         break;
1691                 case PR_TASK_PERF_EVENTS_DISABLE:
1692                         error = perf_event_task_disable();
1693                         break;
1694                 case PR_TASK_PERF_EVENTS_ENABLE:
1695                         error = perf_event_task_enable();
1696                         break;
1697                 case PR_GET_TIMERSLACK:
1698                         error = current->timer_slack_ns;
1699                         break;
1700                 case PR_SET_TIMERSLACK:
1701                         if (arg2 <= 0)
1702                                 current->timer_slack_ns =
1703                                         current->default_timer_slack_ns;
1704                         else
1705                                 current->timer_slack_ns = arg2;
1706                         error = 0;
1707                         break;
1708                 case PR_MCE_KILL:
1709                         if (arg4 | arg5)
1710                                 return -EINVAL;
1711                         switch (arg2) {
1712                         case PR_MCE_KILL_CLEAR:
1713                                 if (arg3 != 0)
1714                                         return -EINVAL;
1715                                 current->flags &= ~PF_MCE_PROCESS;
1716                                 break;
1717                         case PR_MCE_KILL_SET:
1718                                 current->flags |= PF_MCE_PROCESS;
1719                                 if (arg3 == PR_MCE_KILL_EARLY)
1720                                         current->flags |= PF_MCE_EARLY;
1721                                 else if (arg3 == PR_MCE_KILL_LATE)
1722                                         current->flags &= ~PF_MCE_EARLY;
1723                                 else if (arg3 == PR_MCE_KILL_DEFAULT)
1724                                         current->flags &=
1725                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
1726                                 else
1727                                         return -EINVAL;
1728                                 break;
1729                         default:
1730                                 return -EINVAL;
1731                         }
1732                         error = 0;
1733                         break;
1734                 case PR_MCE_KILL_GET:
1735                         if (arg2 | arg3 | arg4 | arg5)
1736                                 return -EINVAL;
1737                         if (current->flags & PF_MCE_PROCESS)
1738                                 error = (current->flags & PF_MCE_EARLY) ?
1739                                         PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
1740                         else
1741                                 error = PR_MCE_KILL_DEFAULT;
1742                         break;
1743                 default:
1744                         error = -EINVAL;
1745                         break;
1746         }
1747         return error;
1748 }
1749
1750 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
1751                 struct getcpu_cache __user *, unused)
1752 {
1753         int err = 0;
1754         int cpu = raw_smp_processor_id();
1755         if (cpup)
1756                 err |= put_user(cpu, cpup);
1757         if (nodep)
1758                 err |= put_user(cpu_to_node(cpu), nodep);
1759         return err ? -EFAULT : 0;
1760 }
1761
1762 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1763
1764 static void argv_cleanup(struct subprocess_info *info)
1765 {
1766         argv_free(info->argv);
1767 }
1768
1769 /**
1770  * orderly_poweroff - Trigger an orderly system poweroff
1771  * @force: force poweroff if command execution fails
1772  *
1773  * This may be called from any context to trigger a system shutdown.
1774  * If the orderly shutdown fails, it will force an immediate shutdown.
1775  */
1776 int orderly_poweroff(bool force)
1777 {
1778         int argc;
1779         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1780         static char *envp[] = {
1781                 "HOME=/",
1782                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1783                 NULL
1784         };
1785         int ret = -ENOMEM;
1786         struct subprocess_info *info;
1787
1788         if (argv == NULL) {
1789                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1790                        __func__, poweroff_cmd);
1791                 goto out;
1792         }
1793
1794         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1795         if (info == NULL) {
1796                 argv_free(argv);
1797                 goto out;
1798         }
1799
1800         call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL);
1801
1802         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1803
1804   out:
1805         if (ret && force) {
1806                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1807                        "forcing the issue\n");
1808
1809                 /* I guess this should try to kick off some daemon to
1810                    sync and poweroff asap.  Or not even bother syncing
1811                    if we're doing an emergency shutdown? */
1812                 emergency_sync();
1813                 kernel_power_off();
1814         }
1815
1816         return ret;
1817 }
1818 EXPORT_SYMBOL_GPL(orderly_poweroff);