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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/perf_counter.h>
  18 #include <linux/resource.h>
  19 #include <linux/kernel.h>
  20 #include <linux/kexec.h>
  21 #include <linux/workqueue.h>
  22 #include <linux/capability.h>
  23 #include <linux/device.h>
  24 #include <linux/key.h>
  25 #include <linux/times.h>
  26 #include <linux/posix-timers.h>
  27 #include <linux/security.h>
  28 #include <linux/dcookies.h>
  29 #include <linux/suspend.h>
  30 #include <linux/tty.h>
  31 #include <linux/signal.h>
  32 #include <linux/cn_proc.h>
  33 #include <linux/getcpu.h>
  34 #include <linux/task_io_accounting_ops.h>
  35 #include <linux/seccomp.h>
  36 #include <linux/cpu.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 static int set_one_prio(struct task_struct *p, int niceval, int error)
 117 {
 118         int no_nice;
 119
 120         if (p->uid != current->euid &&
 121                 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
 122                 error = -EPERM;
 123                 goto out;
 124         }
 125         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 126                 error = -EACCES;
 127                 goto out;
 128         }
 129         no_nice = security_task_setnice(p, niceval);
 130         if (no_nice) {
 131                 error = no_nice;
 132                 goto out;
 133         }
 134         if (error == -ESRCH)
 135                 error = 0;
 136         set_user_nice(p, niceval);
 137 out:
 138         return error;
 139 }
 140
 141 asmlinkage long sys_setpriority(int which, int who, int niceval)
 142 {
 143         struct task_struct *g, *p;
 144         struct user_struct *user;
 145         int error = -EINVAL;
 146         struct pid *pgrp;
 147
 148         if (which > PRIO_USER || which < PRIO_PROCESS)
 149                 goto out;
 150
 151         /* normalize: avoid signed division (rounding problems) */
 152         error = -ESRCH;
 153         if (niceval < -20)
 154                 niceval = -20;
 155         if (niceval > 19)
 156                 niceval = 19;
 157
 158         read_lock(&tasklist_lock);
 159         switch (which) {
 160                 case PRIO_PROCESS:
 161                         if (who)
 162                                 p = find_task_by_vpid(who);
 163                         else
 164                                 p = current;
 165                         if (p)
 166                                 error = set_one_prio(p, niceval, error);
 167                         break;
 168                 case PRIO_PGRP:
 169                         if (who)
 170                                 pgrp = find_vpid(who);
 171                         else
 172                                 pgrp = task_pgrp(current);
 173                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 174                                 error = set_one_prio(p, niceval, error);
 175                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 176                         break;
 177                 case PRIO_USER:
 178                         user = current->user;
 179                         if (!who)
 180                                 who = current->uid;
 181                         else
 182                                 if ((who != current->uid) && !(user = find_user(who)))
 183                                         goto out_unlock;        /* No processes for this user */
 184
 185                         do_each_thread(g, p)
 186                                 if (p->uid == who)
 187                                         error = set_one_prio(p, niceval, error);
 188                         while_each_thread(g, p);
 189                         if (who != current->uid)
 190                                 free_uid(user);         /* For find_user() */
 191                         break;
 192         }
 193 out_unlock:
 194         read_unlock(&tasklist_lock);
 195 out:
 196         return error;
 197 }
 198
 199 /*
 200  * Ugh. To avoid negative return values, "getpriority()" will
 201  * not return the normal nice-value, but a negated value that
 202  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 203  * to stay compatible.
 204  */
 205 asmlinkage long sys_getpriority(int which, int who)
 206 {
 207         struct task_struct *g, *p;
 208         struct user_struct *user;
 209         long niceval, retval = -ESRCH;
 210         struct pid *pgrp;
 211
 212         if (which > PRIO_USER || which < PRIO_PROCESS)
 213                 return -EINVAL;
 214
 215         read_lock(&tasklist_lock);
 216         switch (which) {
 217                 case PRIO_PROCESS:
 218                         if (who)
 219                                 p = find_task_by_vpid(who);
 220                         else
 221                                 p = current;
 222                         if (p) {
 223                                 niceval = 20 - task_nice(p);
 224                                 if (niceval > retval)
 225                                         retval = niceval;
 226                         }
 227                         break;
 228                 case PRIO_PGRP:
 229                         if (who)
 230                                 pgrp = find_vpid(who);
 231                         else
 232                                 pgrp = task_pgrp(current);
 233                         do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 234                                 niceval = 20 - task_nice(p);
 235                                 if (niceval > retval)
 236                                         retval = niceval;
 237                         } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 238                         break;
 239                 case PRIO_USER:
 240                         user = current->user;
 241                         if (!who)
 242                                 who = current->uid;
 243                         else
 244                                 if ((who != current->uid) && !(user = find_user(who)))
 245                                         goto out_unlock;        /* No processes for this user */
 246
 247                         do_each_thread(g, p)
 248                                 if (p->uid == who) {
 249                                         niceval = 20 - task_nice(p);
 250                                         if (niceval > retval)
 251                                                 retval = niceval;
 252                                 }
 253                         while_each_thread(g, p);
 254                         if (who != current->uid)
 255                                 free_uid(user);         /* for find_user() */
 256                         break;
 257         }
 258 out_unlock:
 259         read_unlock(&tasklist_lock);
 260
 261         return retval;
 262 }
 263
 264 /**
 265  *      emergency_restart - reboot the system
 266  *
 267  *      Without shutting down any hardware or taking any locks
 268  *      reboot the system.  This is called when we know we are in
 269  *      trouble so this is our best effort to reboot.  This is
 270  *      safe to call in interrupt context.
 271  */
 272 void emergency_restart(void)
 273 {
 274         machine_emergency_restart();
 275 }
 276 EXPORT_SYMBOL_GPL(emergency_restart);
 277
 278 void kernel_restart_prepare(char *cmd)
 279 {
 280         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 281         system_state = SYSTEM_RESTART;
 282         device_shutdown();
 283         sysdev_shutdown();
 284 }
 285
 286 /**
 287  *      kernel_restart - reboot the system
 288  *      @cmd: pointer to buffer containing command to execute for restart
 289  *              or %NULL
 290  *
 291  *      Shutdown everything and perform a clean reboot.
 292  *      This is not safe to call in interrupt context.
 293  */
 294 void kernel_restart(char *cmd)
 295 {
 296         kernel_restart_prepare(cmd);
 297         if (!cmd)
 298                 printk(KERN_EMERG "Restarting system.\n");
 299         else
 300                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 301         machine_restart(cmd);
 302 }
 303 EXPORT_SYMBOL_GPL(kernel_restart);
 304
 305 static void kernel_shutdown_prepare(enum system_states state)
 306 {
 307         blocking_notifier_call_chain(&reboot_notifier_list,
 308                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 309         system_state = state;
 310         device_shutdown();
 311 }
 312 /**
 313  *      kernel_halt - halt the system
 314  *
 315  *      Shutdown everything and perform a clean system halt.
 316  */
 317 void kernel_halt(void)
 318 {
 319         kernel_shutdown_prepare(SYSTEM_HALT);
 320         sysdev_shutdown();
 321         printk(KERN_EMERG "System halted.\n");
 322         machine_halt();
 323 }
 324
 325 EXPORT_SYMBOL_GPL(kernel_halt);
 326
 327 /**
 328  *      kernel_power_off - power_off the system
 329  *
 330  *      Shutdown everything and perform a clean system power_off.
 331  */
 332 void kernel_power_off(void)
 333 {
 334         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 335         if (pm_power_off_prepare)
 336                 pm_power_off_prepare();
 337         disable_nonboot_cpus();
 338         sysdev_shutdown();
 339         printk(KERN_EMERG "Power down.\n");
 340         machine_power_off();
 341 }
 342 EXPORT_SYMBOL_GPL(kernel_power_off);
 343 /*
 344  * Reboot system call: for obvious reasons only root may call it,
 345  * and even root needs to set up some magic numbers in the registers
 346  * so that some mistake won't make this reboot the whole machine.
 347  * You can also set the meaning of the ctrl-alt-del-key here.
 348  *
 349  * reboot doesn't sync: do that yourself before calling this.
 350  */
 351 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
 352 {
 353         char buffer[256];
 354
 355         /* We only trust the superuser with rebooting the system. */
 356         if (!capable(CAP_SYS_BOOT))
 357                 return -EPERM;
 358
 359         /* For safety, we require "magic" arguments. */
 360         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 361             (magic2 != LINUX_REBOOT_MAGIC2 &&
 362                         magic2 != LINUX_REBOOT_MAGIC2A &&
 363                         magic2 != LINUX_REBOOT_MAGIC2B &&
 364                         magic2 != LINUX_REBOOT_MAGIC2C))
 365                 return -EINVAL;
 366
 367         /* Instead of trying to make the power_off code look like
 368          * halt when pm_power_off is not set do it the easy way.
 369          */
 370         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 371                 cmd = LINUX_REBOOT_CMD_HALT;
 372
 373         lock_kernel();
 374         switch (cmd) {
 375         case LINUX_REBOOT_CMD_RESTART:
 376                 kernel_restart(NULL);
 377                 break;
 378
 379         case LINUX_REBOOT_CMD_CAD_ON:
 380                 C_A_D = 1;
 381                 break;
 382
 383         case LINUX_REBOOT_CMD_CAD_OFF:
 384                 C_A_D = 0;
 385                 break;
 386
 387         case LINUX_REBOOT_CMD_HALT:
 388                 kernel_halt();
 389                 unlock_kernel();
 390                 do_exit(0);
 391                 break;
 392
 393         case LINUX_REBOOT_CMD_POWER_OFF:
 394                 kernel_power_off();
 395                 unlock_kernel();
 396                 do_exit(0);
 397                 break;
 398
 399         case LINUX_REBOOT_CMD_RESTART2:
 400                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 401                         unlock_kernel();
 402                         return -EFAULT;
 403                 }
 404                 buffer[sizeof(buffer) - 1] = '\0';
 405
 406                 kernel_restart(buffer);
 407                 break;
 408
 409 #ifdef CONFIG_KEXEC
 410         case LINUX_REBOOT_CMD_KEXEC:
 411                 {
 412                         int ret;
 413                         ret = kernel_kexec();
 414                         unlock_kernel();
 415                         return ret;
 416                 }
 417 #endif
 418
 419 #ifdef CONFIG_HIBERNATION
 420         case LINUX_REBOOT_CMD_SW_SUSPEND:
 421                 {
 422                         int ret = hibernate();
 423                         unlock_kernel();
 424                         return ret;
 425                 }
 426 #endif
 427
 428         default:
 429                 unlock_kernel();
 430                 return -EINVAL;
 431         }
 432         unlock_kernel();
 433         return 0;
 434 }
 435
 436 static void deferred_cad(struct work_struct *dummy)
 437 {
 438         kernel_restart(NULL);
 439 }
 440
 441 /*
 442  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 443  * As it's called within an interrupt, it may NOT sync: the only choice
 444  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 445  */
 446 void ctrl_alt_del(void)
 447 {
 448         static DECLARE_WORK(cad_work, deferred_cad);
 449
 450         if (C_A_D)
 451                 schedule_work(&cad_work);
 452         else
 453                 kill_cad_pid(SIGINT, 1);
 454 }
 455
 456 /*
 457  * Unprivileged users may change the real gid to the effective gid
 458  * or vice versa.  (BSD-style)
 459  *
 460  * If you set the real gid at all, or set the effective gid to a value not
 461  * equal to the real gid, then the saved gid is set to the new effective gid.
 462  *
 463  * This makes it possible for a setgid program to completely drop its
 464  * privileges, which is often a useful assertion to make when you are doing
 465  * a security audit over a program.
 466  *
 467  * The general idea is that a program which uses just setregid() will be
 468  * 100% compatible with BSD.  A program which uses just setgid() will be
 469  * 100% compatible with POSIX with saved IDs.
 470  *
 471  * SMP: There are not races, the GIDs are checked only by filesystem
 472  *      operations (as far as semantic preservation is concerned).
 473  */
 474 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
 475 {
 476         int old_rgid = current->gid;
 477         int old_egid = current->egid;
 478         int new_rgid = old_rgid;
 479         int new_egid = old_egid;
 480         int retval;
 481
 482         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 483         if (retval)
 484                 return retval;
 485
 486         if (rgid != (gid_t) -1) {
 487                 if ((old_rgid == rgid) ||
 488                     (current->egid==rgid) ||
 489                     capable(CAP_SETGID))
 490                         new_rgid = rgid;
 491                 else
 492                         return -EPERM;
 493         }
 494         if (egid != (gid_t) -1) {
 495                 if ((old_rgid == egid) ||
 496                     (current->egid == egid) ||
 497                     (current->sgid == egid) ||
 498                     capable(CAP_SETGID))
 499                         new_egid = egid;
 500                 else
 501                         return -EPERM;
 502         }
 503         if (new_egid != old_egid) {
 504                 set_dumpable(current->mm, suid_dumpable);
 505                 smp_wmb();
 506         }
 507         if (rgid != (gid_t) -1 ||
 508             (egid != (gid_t) -1 && egid != old_rgid))
 509                 current->sgid = new_egid;
 510         current->fsgid = new_egid;
 511         current->egid = new_egid;
 512         current->gid = new_rgid;
 513         key_fsgid_changed(current);
 514         proc_id_connector(current, PROC_EVENT_GID);
 515         return 0;
 516 }
 517
 518 /*
 519  * setgid() is implemented like SysV w/ SAVED_IDS
 520  *
 521  * SMP: Same implicit races as above.
 522  */
 523 asmlinkage long sys_setgid(gid_t gid)
 524 {
 525         int old_egid = current->egid;
 526         int retval;
 527
 528         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 529         if (retval)
 530                 return retval;
 531
 532         if (capable(CAP_SETGID)) {
 533                 if (old_egid != gid) {
 534                         set_dumpable(current->mm, suid_dumpable);
 535                         smp_wmb();
 536                 }
 537                 current->gid = current->egid = current->sgid = current->fsgid = gid;
 538         } else if ((gid == current->gid) || (gid == current->sgid)) {
 539                 if (old_egid != gid) {
 540                         set_dumpable(current->mm, suid_dumpable);
 541                         smp_wmb();
 542                 }
 543                 current->egid = current->fsgid = gid;
 544         }
 545         else
 546                 return -EPERM;
 547
 548         key_fsgid_changed(current);
 549         proc_id_connector(current, PROC_EVENT_GID);
 550         return 0;
 551 }
 552
 553 static int set_user(uid_t new_ruid, int dumpclear)
 554 {
 555         struct user_struct *new_user;
 556
 557         new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
 558         if (!new_user)
 559                 return -EAGAIN;
 560
 561         if (atomic_read(&new_user->processes) >=
 562                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 563                         new_user != current->nsproxy->user_ns->root_user) {
 564                 free_uid(new_user);
 565                 return -EAGAIN;
 566         }
 567
 568         switch_uid(new_user);
 569
 570         if (dumpclear) {
 571                 set_dumpable(current->mm, suid_dumpable);
 572                 smp_wmb();
 573         }
 574         current->uid = new_ruid;
 575         return 0;
 576 }
 577
 578 /*
 579  * Unprivileged users may change the real uid to the effective uid
 580  * or vice versa.  (BSD-style)
 581  *
 582  * If you set the real uid at all, or set the effective uid to a value not
 583  * equal to the real uid, then the saved uid is set to the new effective uid.
 584  *
 585  * This makes it possible for a setuid program to completely drop its
 586  * privileges, which is often a useful assertion to make when you are doing
 587  * a security audit over a program.
 588  *
 589  * The general idea is that a program which uses just setreuid() will be
 590  * 100% compatible with BSD.  A program which uses just setuid() will be
 591  * 100% compatible with POSIX with saved IDs.
 592  */
 593 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 594 {
 595         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
 596         int retval;
 597
 598         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 599         if (retval)
 600                 return retval;
 601
 602         new_ruid = old_ruid = current->uid;
 603         new_euid = old_euid = current->euid;
 604         old_suid = current->suid;
 605
 606         if (ruid != (uid_t) -1) {
 607                 new_ruid = ruid;
 608                 if ((old_ruid != ruid) &&
 609                     (current->euid != ruid) &&
 610                     !capable(CAP_SETUID))
 611                         return -EPERM;
 612         }
 613
 614         if (euid != (uid_t) -1) {
 615                 new_euid = euid;
 616                 if ((old_ruid != euid) &&
 617                     (current->euid != euid) &&
 618                     (current->suid != euid) &&
 619                     !capable(CAP_SETUID))
 620                         return -EPERM;
 621         }
 622
 623         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
 624                 return -EAGAIN;
 625
 626         if (new_euid != old_euid) {
 627                 set_dumpable(current->mm, suid_dumpable);
 628                 smp_wmb();
 629         }
 630         current->fsuid = current->euid = new_euid;
 631         if (ruid != (uid_t) -1 ||
 632             (euid != (uid_t) -1 && euid != old_ruid))
 633                 current->suid = current->euid;
 634         current->fsuid = current->euid;
 635
 636         key_fsuid_changed(current);
 637         proc_id_connector(current, PROC_EVENT_UID);
 638
 639         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
 640 }
 641
 642
 643
 644 /*
 645  * setuid() is implemented like SysV with SAVED_IDS
 646  *
 647  * Note that SAVED_ID's is deficient in that a setuid root program
 648  * like sendmail, for example, cannot set its uid to be a normal
 649  * user and then switch back, because if you're root, setuid() sets
 650  * the saved uid too.  If you don't like this, blame the bright people
 651  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 652  * will allow a root program to temporarily drop privileges and be able to
 653  * regain them by swapping the real and effective uid.
 654  */
 655 asmlinkage long sys_setuid(uid_t uid)
 656 {
 657         int old_euid = current->euid;
 658         int old_ruid, old_suid, new_suid;
 659         int retval;
 660
 661         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 662         if (retval)
 663                 return retval;
 664
 665         old_ruid = current->uid;
 666         old_suid = current->suid;
 667         new_suid = old_suid;
 668
 669         if (capable(CAP_SETUID)) {
 670                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
 671                         return -EAGAIN;
 672                 new_suid = uid;
 673         } else if ((uid != current->uid) && (uid != new_suid))
 674                 return -EPERM;
 675
 676         if (old_euid != uid) {
 677                 set_dumpable(current->mm, suid_dumpable);
 678                 smp_wmb();
 679         }
 680         current->fsuid = current->euid = uid;
 681         current->suid = new_suid;
 682
 683         key_fsuid_changed(current);
 684         proc_id_connector(current, PROC_EVENT_UID);
 685
 686         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
 687 }
 688
 689
 690 /*
 691  * This function implements a generic ability to update ruid, euid,
 692  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 693  */
 694 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 695 {
 696         int old_ruid = current->uid;
 697         int old_euid = current->euid;
 698         int old_suid = current->suid;
 699         int retval;
 700
 701         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 702         if (retval)
 703                 return retval;
 704
 705         if (!capable(CAP_SETUID)) {
 706                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
 707                     (ruid != current->euid) && (ruid != current->suid))
 708                         return -EPERM;
 709                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
 710                     (euid != current->euid) && (euid != current->suid))
 711                         return -EPERM;
 712                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
 713                     (suid != current->euid) && (suid != current->suid))
 714                         return -EPERM;
 715         }
 716         if (ruid != (uid_t) -1) {
 717                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
 718                         return -EAGAIN;
 719         }
 720         if (euid != (uid_t) -1) {
 721                 if (euid != current->euid) {
 722                         set_dumpable(current->mm, suid_dumpable);
 723                         smp_wmb();
 724                 }
 725                 current->euid = euid;
 726         }
 727         current->fsuid = current->euid;
 728         if (suid != (uid_t) -1)
 729                 current->suid = suid;
 730
 731         key_fsuid_changed(current);
 732         proc_id_connector(current, PROC_EVENT_UID);
 733
 734         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
 735 }
 736
 737 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
 738 {
 739         int retval;
 740
 741         if (!(retval = put_user(current->uid, ruid)) &&
 742             !(retval = put_user(current->euid, euid)))
 743                 retval = put_user(current->suid, suid);
 744
 745         return retval;
 746 }
 747
 748 /*
 749  * Same as above, but for rgid, egid, sgid.
 750  */
 751 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 752 {
 753         int retval;
 754
 755         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 756         if (retval)
 757                 return retval;
 758
 759         if (!capable(CAP_SETGID)) {
 760                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
 761                     (rgid != current->egid) && (rgid != current->sgid))
 762                         return -EPERM;
 763                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
 764                     (egid != current->egid) && (egid != current->sgid))
 765                         return -EPERM;
 766                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
 767                     (sgid != current->egid) && (sgid != current->sgid))
 768                         return -EPERM;
 769         }
 770         if (egid != (gid_t) -1) {
 771                 if (egid != current->egid) {
 772                         set_dumpable(current->mm, suid_dumpable);
 773                         smp_wmb();
 774                 }
 775                 current->egid = egid;
 776         }
 777         current->fsgid = current->egid;
 778         if (rgid != (gid_t) -1)
 779                 current->gid = rgid;
 780         if (sgid != (gid_t) -1)
 781                 current->sgid = sgid;
 782
 783         key_fsgid_changed(current);
 784         proc_id_connector(current, PROC_EVENT_GID);
 785         return 0;
 786 }
 787
 788 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
 789 {
 790         int retval;
 791
 792         if (!(retval = put_user(current->gid, rgid)) &&
 793             !(retval = put_user(current->egid, egid)))
 794                 retval = put_user(current->sgid, sgid);
 795
 796         return retval;
 797 }
 798
 799
 800 /*
 801  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 802  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 803  * whatever uid it wants to). It normally shadows "euid", except when
 804  * explicitly set by setfsuid() or for access..
 805  */
 806 asmlinkage long sys_setfsuid(uid_t uid)
 807 {
 808         int old_fsuid;
 809
 810         old_fsuid = current->fsuid;
 811         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
 812                 return old_fsuid;
 813
 814         if (uid == current->uid || uid == current->euid ||
 815             uid == current->suid || uid == current->fsuid ||
 816             capable(CAP_SETUID)) {
 817                 if (uid != old_fsuid) {
 818                         set_dumpable(current->mm, suid_dumpable);
 819                         smp_wmb();
 820                 }
 821                 current->fsuid = uid;
 822         }
 823
 824         key_fsuid_changed(current);
 825         proc_id_connector(current, PROC_EVENT_UID);
 826
 827         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
 828
 829         return old_fsuid;
 830 }
 831
 832 /*
 833  * Samma på svenska..
 834  */
 835 asmlinkage long sys_setfsgid(gid_t gid)
 836 {
 837         int old_fsgid;
 838
 839         old_fsgid = current->fsgid;
 840         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 841                 return old_fsgid;
 842
 843         if (gid == current->gid || gid == current->egid ||
 844             gid == current->sgid || gid == current->fsgid ||
 845             capable(CAP_SETGID)) {
 846                 if (gid != old_fsgid) {
 847                         set_dumpable(current->mm, suid_dumpable);
 848                         smp_wmb();
 849                 }
 850                 current->fsgid = gid;
 851                 key_fsgid_changed(current);
 852                 proc_id_connector(current, PROC_EVENT_GID);
 853         }
 854         return old_fsgid;
 855 }
 856
 857 void do_sys_times(struct tms *tms)
 858 {
 859         struct task_cputime cputime;
 860         cputime_t cutime, cstime;
 861
 862         spin_lock_irq(&current->sighand->siglock);
 863         thread_group_cputime(current, &cputime);
 864         cutime = current->signal->cutime;
 865         cstime = current->signal->cstime;
 866         spin_unlock_irq(&current->sighand->siglock);
 867         tms->tms_utime = cputime_to_clock_t(cputime.utime);
 868         tms->tms_stime = cputime_to_clock_t(cputime.stime);
 869         tms->tms_cutime = cputime_to_clock_t(cutime);
 870         tms->tms_cstime = cputime_to_clock_t(cstime);
 871 }
 872
 873 asmlinkage long sys_times(struct tms __user * tbuf)
 874 {
 875         if (tbuf) {
 876                 struct tms tmp;
 877
 878                 do_sys_times(&tmp);
 879                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 880                         return -EFAULT;
 881         }
 882         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 883 }
 884
 885 /*
 886  * This needs some heavy checking ...
 887  * I just haven't the stomach for it. I also don't fully
 888  * understand sessions/pgrp etc. Let somebody who does explain it.
 889  *
 890  * OK, I think I have the protection semantics right.... this is really
 891  * only important on a multi-user system anyway, to make sure one user
 892  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 893  *
 894  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 895  * LBT 04.03.94
 896  */
 897 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 898 {
 899         struct task_struct *p;
 900         struct task_struct *group_leader = current->group_leader;
 901         struct pid *pgrp;
 902         int err;
 903
 904         if (!pid)
 905                 pid = task_pid_vnr(group_leader);
 906         if (!pgid)
 907                 pgid = pid;
 908         if (pgid < 0)
 909                 return -EINVAL;
 910
 911         /* From this point forward we keep holding onto the tasklist lock
 912          * so that our parent does not change from under us. -DaveM
 913          */
 914         write_lock_irq(&tasklist_lock);
 915
 916         err = -ESRCH;
 917         p = find_task_by_vpid(pid);
 918         if (!p)
 919                 goto out;
 920
 921         err = -EINVAL;
 922         if (!thread_group_leader(p))
 923                 goto out;
 924
 925         if (same_thread_group(p->real_parent, group_leader)) {
 926                 err = -EPERM;
 927                 if (task_session(p) != task_session(group_leader))
 928                         goto out;
 929                 err = -EACCES;
 930                 if (p->did_exec)
 931                         goto out;
 932         } else {
 933                 err = -ESRCH;
 934                 if (p != group_leader)
 935                         goto out;
 936         }
 937
 938         err = -EPERM;
 939         if (p->signal->leader)
 940                 goto out;
 941
 942         pgrp = task_pid(p);
 943         if (pgid != pid) {
 944                 struct task_struct *g;
 945
 946                 pgrp = find_vpid(pgid);
 947                 g = pid_task(pgrp, PIDTYPE_PGID);
 948                 if (!g || task_session(g) != task_session(group_leader))
 949                         goto out;
 950         }
 951
 952         err = security_task_setpgid(p, pgid);
 953         if (err)
 954                 goto out;
 955
 956         if (task_pgrp(p) != pgrp) {
 957                 change_pid(p, PIDTYPE_PGID, pgrp);
 958                 set_task_pgrp(p, pid_nr(pgrp));
 959         }
 960
 961         err = 0;
 962 out:
 963         /* All paths lead to here, thus we are safe. -DaveM */
 964         write_unlock_irq(&tasklist_lock);
 965         return err;
 966 }
 967
 968 asmlinkage long sys_getpgid(pid_t pid)
 969 {
 970         struct task_struct *p;
 971         struct pid *grp;
 972         int retval;
 973
 974         rcu_read_lock();
 975         if (!pid)
 976                 grp = task_pgrp(current);
 977         else {
 978                 retval = -ESRCH;
 979                 p = find_task_by_vpid(pid);
 980                 if (!p)
 981                         goto out;
 982                 grp = task_pgrp(p);
 983                 if (!grp)
 984                         goto out;
 985
 986                 retval = security_task_getpgid(p);
 987                 if (retval)
 988                         goto out;
 989         }
 990         retval = pid_vnr(grp);
 991 out:
 992         rcu_read_unlock();
 993         return retval;
 994 }
 995
 996 #ifdef __ARCH_WANT_SYS_GETPGRP
 997
 998 asmlinkage long sys_getpgrp(void)
 999 {
1000         return sys_getpgid(0);
1001 }
1002
1003 #endif
1004
1005 asmlinkage long sys_getsid(pid_t pid)
1006 {
1007         struct task_struct *p;
1008         struct pid *sid;
1009         int retval;
1010
1011         rcu_read_lock();
1012         if (!pid)
1013                 sid = task_session(current);
1014         else {
1015                 retval = -ESRCH;
1016                 p = find_task_by_vpid(pid);
1017                 if (!p)
1018                         goto out;
1019                 sid = task_session(p);
1020                 if (!sid)
1021                         goto out;
1022
1023                 retval = security_task_getsid(p);
1024                 if (retval)
1025                         goto out;
1026         }
1027         retval = pid_vnr(sid);
1028 out:
1029         rcu_read_unlock();
1030         return retval;
1031 }
1032
1033 asmlinkage long sys_setsid(void)
1034 {
1035         struct task_struct *group_leader = current->group_leader;
1036         struct pid *sid = task_pid(group_leader);
1037         pid_t session = pid_vnr(sid);
1038         int err = -EPERM;
1039
1040         write_lock_irq(&tasklist_lock);
1041         /* Fail if I am already a session leader */
1042         if (group_leader->signal->leader)
1043                 goto out;
1044
1045         /* Fail if a process group id already exists that equals the
1046          * proposed session id.
1047          */
1048         if (pid_task(sid, PIDTYPE_PGID))
1049                 goto out;
1050
1051         group_leader->signal->leader = 1;
1052         __set_special_pids(sid);
1053
1054         proc_clear_tty(group_leader);
1055
1056         err = session;
1057 out:
1058         write_unlock_irq(&tasklist_lock);
1059         return err;
1060 }
1061
1062 /*
1063  * Supplementary group IDs
1064  */
1065
1066 /* init to 2 - one for init_task, one to ensure it is never freed */
1067 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1068
1069 struct group_info *groups_alloc(int gidsetsize)
1070 {
1071         struct group_info *group_info;
1072         int nblocks;
1073         int i;
1074
1075         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1076         /* Make sure we always allocate at least one indirect block pointer */
1077         nblocks = nblocks ? : 1;
1078         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1079         if (!group_info)
1080                 return NULL;
1081         group_info->ngroups = gidsetsize;
1082         group_info->nblocks = nblocks;
1083         atomic_set(&group_info->usage, 1);
1084
1085         if (gidsetsize <= NGROUPS_SMALL)
1086                 group_info->blocks[0] = group_info->small_block;
1087         else {
1088                 for (i = 0; i < nblocks; i++) {
1089                         gid_t *b;
1090                         b = (void *)__get_free_page(GFP_USER);
1091                         if (!b)
1092                                 goto out_undo_partial_alloc;
1093                         group_info->blocks[i] = b;
1094                 }
1095         }
1096         return group_info;
1097
1098 out_undo_partial_alloc:
1099         while (--i >= 0) {
1100                 free_page((unsigned long)group_info->blocks[i]);
1101         }
1102         kfree(group_info);
1103         return NULL;
1104 }
1105
1106 EXPORT_SYMBOL(groups_alloc);
1107
1108 void groups_free(struct group_info *group_info)
1109 {
1110         if (group_info->blocks[0] != group_info->small_block) {
1111                 int i;
1112                 for (i = 0; i < group_info->nblocks; i++)
1113                         free_page((unsigned long)group_info->blocks[i]);
1114         }
1115         kfree(group_info);
1116 }
1117
1118 EXPORT_SYMBOL(groups_free);
1119
1120 /* export the group_info to a user-space array */
1121 static int groups_to_user(gid_t __user *grouplist,
1122     struct group_info *group_info)
1123 {
1124         int i;
1125         unsigned int count = group_info->ngroups;
1126
1127         for (i = 0; i < group_info->nblocks; i++) {
1128                 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1129                 unsigned int len = cp_count * sizeof(*grouplist);
1130
1131                 if (copy_to_user(grouplist, group_info->blocks[i], len))
1132                         return -EFAULT;
1133
1134                 grouplist += NGROUPS_PER_BLOCK;
1135                 count -= cp_count;
1136         }
1137         return 0;
1138 }
1139
1140 /* fill a group_info from a user-space array - it must be allocated already */
1141 static int groups_from_user(struct group_info *group_info,
1142     gid_t __user *grouplist)
1143 {
1144         int i;
1145         unsigned int count = group_info->ngroups;
1146
1147         for (i = 0; i < group_info->nblocks; i++) {
1148                 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1149                 unsigned int len = cp_count * sizeof(*grouplist);
1150
1151                 if (copy_from_user(group_info->blocks[i], grouplist, len))
1152                         return -EFAULT;
1153
1154                 grouplist += NGROUPS_PER_BLOCK;
1155                 count -= cp_count;
1156         }
1157         return 0;
1158 }
1159
1160 /* a simple Shell sort */
1161 static void groups_sort(struct group_info *group_info)
1162 {
1163         int base, max, stride;
1164         int gidsetsize = group_info->ngroups;
1165
1166         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1167                 ; /* nothing */
1168         stride /= 3;
1169
1170         while (stride) {
1171                 max = gidsetsize - stride;
1172                 for (base = 0; base < max; base++) {
1173                         int left = base;
1174                         int right = left + stride;
1175                         gid_t tmp = GROUP_AT(group_info, right);
1176
1177                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1178                                 GROUP_AT(group_info, right) =
1179                                     GROUP_AT(group_info, left);
1180                                 right = left;
1181                                 left -= stride;
1182                         }
1183                         GROUP_AT(group_info, right) = tmp;
1184                 }
1185                 stride /= 3;
1186         }
1187 }
1188
1189 /* a simple bsearch */
1190 int groups_search(struct group_info *group_info, gid_t grp)
1191 {
1192         unsigned int left, right;
1193
1194         if (!group_info)
1195                 return 0;
1196
1197         left = 0;
1198         right = group_info->ngroups;
1199         while (left < right) {
1200                 unsigned int mid = (left+right)/2;
1201                 int cmp = grp - GROUP_AT(group_info, mid);
1202                 if (cmp > 0)
1203                         left = mid + 1;
1204                 else if (cmp < 0)
1205                         right = mid;
1206                 else
1207                         return 1;
1208         }
1209         return 0;
1210 }
1211
1212 /* validate and set current->group_info */
1213 int set_current_groups(struct group_info *group_info)
1214 {
1215         int retval;
1216         struct group_info *old_info;
1217
1218         retval = security_task_setgroups(group_info);
1219         if (retval)
1220                 return retval;
1221
1222         groups_sort(group_info);
1223         get_group_info(group_info);
1224
1225         task_lock(current);
1226         old_info = current->group_info;
1227         current->group_info = group_info;
1228         task_unlock(current);
1229
1230         put_group_info(old_info);
1231
1232         return 0;
1233 }
1234
1235 EXPORT_SYMBOL(set_current_groups);
1236
1237 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1238 {
1239         int i = 0;
1240
1241         /*
1242          *      SMP: Nobody else can change our grouplist. Thus we are
1243          *      safe.
1244          */
1245
1246         if (gidsetsize < 0)
1247                 return -EINVAL;
1248
1249         /* no need to grab task_lock here; it cannot change */
1250         i = current->group_info->ngroups;
1251         if (gidsetsize) {
1252                 if (i > gidsetsize) {
1253                         i = -EINVAL;
1254                         goto out;
1255                 }
1256                 if (groups_to_user(grouplist, current->group_info)) {
1257                         i = -EFAULT;
1258                         goto out;
1259                 }
1260         }
1261 out:
1262         return i;
1263 }
1264
1265 /*
1266  *      SMP: Our groups are copy-on-write. We can set them safely
1267  *      without another task interfering.
1268  */
1269
1270 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1271 {
1272         struct group_info *group_info;
1273         int retval;
1274
1275         if (!capable(CAP_SETGID))
1276                 return -EPERM;
1277         if ((unsigned)gidsetsize > NGROUPS_MAX)
1278                 return -EINVAL;
1279
1280         group_info = groups_alloc(gidsetsize);
1281         if (!group_info)
1282                 return -ENOMEM;
1283         retval = groups_from_user(group_info, grouplist);
1284         if (retval) {
1285                 put_group_info(group_info);
1286                 return retval;
1287         }
1288
1289         retval = set_current_groups(group_info);
1290         put_group_info(group_info);
1291
1292         return retval;
1293 }
1294
1295 /*
1296  * Check whether we're fsgid/egid or in the supplemental group..
1297  */
1298 int in_group_p(gid_t grp)
1299 {
1300         int retval = 1;
1301         if (grp != current->fsgid)
1302                 retval = groups_search(current->group_info, grp);
1303         return retval;
1304 }
1305
1306 EXPORT_SYMBOL(in_group_p);
1307
1308 int in_egroup_p(gid_t grp)
1309 {
1310         int retval = 1;
1311         if (grp != current->egid)
1312                 retval = groups_search(current->group_info, grp);
1313         return retval;
1314 }
1315
1316 EXPORT_SYMBOL(in_egroup_p);
1317
1318 DECLARE_RWSEM(uts_sem);
1319
1320 asmlinkage long sys_newuname(struct new_utsname __user * name)
1321 {
1322         int errno = 0;
1323
1324         down_read(&uts_sem);
1325         if (copy_to_user(name, utsname(), sizeof *name))
1326                 errno = -EFAULT;
1327         up_read(&uts_sem);
1328         return errno;
1329 }
1330
1331 asmlinkage long sys_sethostname(char __user *name, int len)
1332 {
1333         int errno;
1334         char tmp[__NEW_UTS_LEN];
1335
1336         if (!capable(CAP_SYS_ADMIN))
1337                 return -EPERM;
1338         if (len < 0 || len > __NEW_UTS_LEN)
1339                 return -EINVAL;
1340         down_write(&uts_sem);
1341         errno = -EFAULT;
1342         if (!copy_from_user(tmp, name, len)) {
1343                 struct new_utsname *u = utsname();
1344
1345                 memcpy(u->nodename, tmp, len);
1346                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1347                 errno = 0;
1348         }
1349         up_write(&uts_sem);
1350         return errno;
1351 }
1352
1353 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1354
1355 asmlinkage long sys_gethostname(char __user *name, int len)
1356 {
1357         int i, errno;
1358         struct new_utsname *u;
1359
1360         if (len < 0)
1361                 return -EINVAL;
1362         down_read(&uts_sem);
1363         u = utsname();
1364         i = 1 + strlen(u->nodename);
1365         if (i > len)
1366                 i = len;
1367         errno = 0;
1368         if (copy_to_user(name, u->nodename, i))
1369                 errno = -EFAULT;
1370         up_read(&uts_sem);
1371         return errno;
1372 }
1373
1374 #endif
1375
1376 /*
1377  * Only setdomainname; getdomainname can be implemented by calling
1378  * uname()
1379  */
1380 asmlinkage long sys_setdomainname(char __user *name, int len)
1381 {
1382         int errno;
1383         char tmp[__NEW_UTS_LEN];
1384
1385         if (!capable(CAP_SYS_ADMIN))
1386                 return -EPERM;
1387         if (len < 0 || len > __NEW_UTS_LEN)
1388                 return -EINVAL;
1389
1390         down_write(&uts_sem);
1391         errno = -EFAULT;
1392         if (!copy_from_user(tmp, name, len)) {
1393                 struct new_utsname *u = utsname();
1394
1395                 memcpy(u->domainname, tmp, len);
1396                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1397                 errno = 0;
1398         }
1399         up_write(&uts_sem);
1400         return errno;
1401 }
1402
1403 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1404 {
1405         if (resource >= RLIM_NLIMITS)
1406                 return -EINVAL;
1407         else {
1408                 struct rlimit value;
1409                 task_lock(current->group_leader);
1410                 value = current->signal->rlim[resource];
1411                 task_unlock(current->group_leader);
1412                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1413         }
1414 }
1415
1416 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1417
1418 /*
1419  *      Back compatibility for getrlimit. Needed for some apps.
1420  */
1421
1422 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1423 {
1424         struct rlimit x;
1425         if (resource >= RLIM_NLIMITS)
1426                 return -EINVAL;
1427
1428         task_lock(current->group_leader);
1429         x = current->signal->rlim[resource];
1430         task_unlock(current->group_leader);
1431         if (x.rlim_cur > 0x7FFFFFFF)
1432                 x.rlim_cur = 0x7FFFFFFF;
1433         if (x.rlim_max > 0x7FFFFFFF)
1434                 x.rlim_max = 0x7FFFFFFF;
1435         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1436 }
1437
1438 #endif
1439
1440 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1441 {
1442         struct rlimit new_rlim, *old_rlim;
1443         int retval;
1444
1445         if (resource >= RLIM_NLIMITS)
1446                 return -EINVAL;
1447         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1448                 return -EFAULT;
1449         old_rlim = current->signal->rlim + resource;
1450         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1451             !capable(CAP_SYS_RESOURCE))
1452                 return -EPERM;
1453
1454         if (resource == RLIMIT_NOFILE) {
1455                 if (new_rlim.rlim_max == RLIM_INFINITY)
1456                         new_rlim.rlim_max = sysctl_nr_open;
1457                 if (new_rlim.rlim_cur == RLIM_INFINITY)
1458                         new_rlim.rlim_cur = sysctl_nr_open;
1459                 if (new_rlim.rlim_max > sysctl_nr_open)
1460                         return -EPERM;
1461         }
1462
1463         if (new_rlim.rlim_cur > new_rlim.rlim_max)
1464                 return -EINVAL;
1465
1466         retval = security_task_setrlimit(resource, &new_rlim);
1467         if (retval)
1468                 return retval;
1469
1470         if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1471                 /*
1472                  * The caller is asking for an immediate RLIMIT_CPU
1473                  * expiry.  But we use the zero value to mean "it was
1474                  * never set".  So let's cheat and make it one second
1475                  * instead
1476                  */
1477                 new_rlim.rlim_cur = 1;
1478         }
1479
1480         task_lock(current->group_leader);
1481         *old_rlim = new_rlim;
1482         task_unlock(current->group_leader);
1483
1484         if (resource != RLIMIT_CPU)
1485                 goto out;
1486
1487         /*
1488          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1489          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1490          * very long-standing error, and fixing it now risks breakage of
1491          * applications, so we live with it
1492          */
1493         if (new_rlim.rlim_cur == RLIM_INFINITY)
1494                 goto out;
1495
1496         update_rlimit_cpu(new_rlim.rlim_cur);
1497 out:
1498         return 0;
1499 }
1500
1501 /*
1502  * It would make sense to put struct rusage in the task_struct,
1503  * except that would make the task_struct be *really big*.  After
1504  * task_struct gets moved into malloc'ed memory, it would
1505  * make sense to do this.  It will make moving the rest of the information
1506  * a lot simpler!  (Which we're not doing right now because we're not
1507  * measuring them yet).
1508  *
1509  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1510  * races with threads incrementing their own counters.  But since word
1511  * reads are atomic, we either get new values or old values and we don't
1512  * care which for the sums.  We always take the siglock to protect reading
1513  * the c* fields from p->signal from races with exit.c updating those
1514  * fields when reaping, so a sample either gets all the additions of a
1515  * given child after it's reaped, or none so this sample is before reaping.
1516  *
1517  * Locking:
1518  * We need to take the siglock for CHILDEREN, SELF and BOTH
1519  * for  the cases current multithreaded, non-current single threaded
1520  * non-current multithreaded.  Thread traversal is now safe with
1521  * the siglock held.
1522  * Strictly speaking, we donot need to take the siglock if we are current and
1523  * single threaded,  as no one else can take our signal_struct away, no one
1524  * else can  reap the  children to update signal->c* counters, and no one else
1525  * can race with the signal-> fields. If we do not take any lock, the
1526  * signal-> fields could be read out of order while another thread was just
1527  * exiting. So we should  place a read memory barrier when we avoid the lock.
1528  * On the writer side,  write memory barrier is implied in  __exit_signal
1529  * as __exit_signal releases  the siglock spinlock after updating the signal->
1530  * fields. But we don't do this yet to keep things simple.
1531  *
1532  */
1533
1534 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1535 {
1536         r->ru_nvcsw += t->nvcsw;
1537         r->ru_nivcsw += t->nivcsw;
1538         r->ru_minflt += t->min_flt;
1539         r->ru_majflt += t->maj_flt;
1540         r->ru_inblock += task_io_get_inblock(t);
1541         r->ru_oublock += task_io_get_oublock(t);
1542 }
1543
1544 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1545 {
1546         struct task_struct *t;
1547         unsigned long flags;
1548         cputime_t utime, stime;
1549         struct task_cputime cputime;
1550
1551         memset((char *) r, 0, sizeof *r);
1552         utime = stime = cputime_zero;
1553
1554         if (who == RUSAGE_THREAD) {
1555                 accumulate_thread_rusage(p, r);
1556                 goto out;
1557         }
1558
1559         if (!lock_task_sighand(p, &flags))
1560                 return;
1561
1562         switch (who) {
1563                 case RUSAGE_BOTH:
1564                 case RUSAGE_CHILDREN:
1565                         utime = p->signal->cutime;
1566                         stime = p->signal->cstime;
1567                         r->ru_nvcsw = p->signal->cnvcsw;
1568                         r->ru_nivcsw = p->signal->cnivcsw;
1569                         r->ru_minflt = p->signal->cmin_flt;
1570                         r->ru_majflt = p->signal->cmaj_flt;
1571                         r->ru_inblock = p->signal->cinblock;
1572                         r->ru_oublock = p->signal->coublock;
1573
1574                         if (who == RUSAGE_CHILDREN)
1575                                 break;
1576
1577                 case RUSAGE_SELF:
1578                         thread_group_cputime(p, &cputime);
1579                         utime = cputime_add(utime, cputime.utime);
1580                         stime = cputime_add(stime, cputime.stime);
1581                         r->ru_nvcsw += p->signal->nvcsw;
1582                         r->ru_nivcsw += p->signal->nivcsw;
1583                         r->ru_minflt += p->signal->min_flt;
1584                         r->ru_majflt += p->signal->maj_flt;
1585                         r->ru_inblock += p->signal->inblock;
1586                         r->ru_oublock += p->signal->oublock;
1587                         t = p;
1588                         do {
1589                                 accumulate_thread_rusage(t, r);
1590                                 t = next_thread(t);
1591                         } while (t != p);
1592                         break;
1593
1594                 default:
1595                         BUG();
1596         }
1597         unlock_task_sighand(p, &flags);
1598
1599 out:
1600         cputime_to_timeval(utime, &r->ru_utime);
1601         cputime_to_timeval(stime, &r->ru_stime);
1602 }
1603
1604 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1605 {
1606         struct rusage r;
1607         k_getrusage(p, who, &r);
1608         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1609 }
1610
1611 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1612 {
1613         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1614             who != RUSAGE_THREAD)
1615                 return -EINVAL;
1616         return getrusage(current, who, ru);
1617 }
1618
1619 asmlinkage long sys_umask(int mask)
1620 {
1621         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1622         return mask;
1623 }
1624
1625 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1626                           unsigned long arg4, unsigned long arg5)
1627 {
1628         long error = 0;
1629
1630         if (security_task_prctl(option, arg2, arg3, arg4, arg5, &error))
1631                 return error;
1632
1633         switch (option) {
1634                 case PR_SET_PDEATHSIG:
1635                         if (!valid_signal(arg2)) {
1636                                 error = -EINVAL;
1637                                 break;
1638                         }
1639                         current->pdeath_signal = arg2;
1640                         break;
1641                 case PR_GET_PDEATHSIG:
1642                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1643                         break;
1644                 case PR_GET_DUMPABLE:
1645                         error = get_dumpable(current->mm);
1646                         break;
1647                 case PR_SET_DUMPABLE:
1648                         if (arg2 < 0 || arg2 > 1) {
1649                                 error = -EINVAL;
1650                                 break;
1651                         }
1652                         set_dumpable(current->mm, arg2);
1653                         break;
1654
1655                 case PR_SET_UNALIGN:
1656                         error = SET_UNALIGN_CTL(current, arg2);
1657                         break;
1658                 case PR_GET_UNALIGN:
1659                         error = GET_UNALIGN_CTL(current, arg2);
1660                         break;
1661                 case PR_SET_FPEMU:
1662                         error = SET_FPEMU_CTL(current, arg2);
1663                         break;
1664                 case PR_GET_FPEMU:
1665                         error = GET_FPEMU_CTL(current, arg2);
1666                         break;
1667                 case PR_SET_FPEXC:
1668                         error = SET_FPEXC_CTL(current, arg2);
1669                         break;
1670                 case PR_GET_FPEXC:
1671                         error = GET_FPEXC_CTL(current, arg2);
1672                         break;
1673                 case PR_GET_TIMING:
1674                         error = PR_TIMING_STATISTICAL;
1675                         break;
1676                 case PR_SET_TIMING:
1677                         if (arg2 != PR_TIMING_STATISTICAL)
1678                                 error = -EINVAL;
1679                         break;
1680
1681                 case PR_SET_NAME: {
1682                         struct task_struct *me = current;
1683                         unsigned char ncomm[sizeof(me->comm)];
1684
1685                         ncomm[sizeof(me->comm)-1] = 0;
1686                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1687                                                 sizeof(me->comm)-1) < 0)
1688                                 return -EFAULT;
1689                         set_task_comm(me, ncomm);
1690                         return 0;
1691                 }
1692                 case PR_GET_NAME: {
1693                         struct task_struct *me = current;
1694                         unsigned char tcomm[sizeof(me->comm)];
1695
1696                         get_task_comm(tcomm, me);
1697                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1698                                 return -EFAULT;
1699                         return 0;
1700                 }
1701                 case PR_GET_ENDIAN:
1702                         error = GET_ENDIAN(current, arg2);
1703                         break;
1704                 case PR_SET_ENDIAN:
1705                         error = SET_ENDIAN(current, arg2);
1706                         break;
1707
1708                 case PR_GET_SECCOMP:
1709                         error = prctl_get_seccomp();
1710                         break;
1711                 case PR_SET_SECCOMP:
1712                         error = prctl_set_seccomp(arg2);
1713                         break;
1714                 case PR_GET_TSC:
1715                         error = GET_TSC_CTL(arg2);
1716                         break;
1717                 case PR_SET_TSC:
1718                         error = SET_TSC_CTL(arg2);
1719                         break;
1720                 case PR_TASK_PERF_COUNTERS_DISABLE:
1721                         error = perf_counter_task_disable();
1722                         break;
1723                 case PR_TASK_PERF_COUNTERS_ENABLE:
1724                         error = perf_counter_task_enable();
1725                         break;
1726                 case PR_GET_TIMERSLACK:
1727                         error = current->timer_slack_ns;
1728                         break;
1729                 case PR_SET_TIMERSLACK:
1730                         if (arg2 <= 0)
1731                                 current->timer_slack_ns =
1732                                         current->default_timer_slack_ns;
1733                         else
1734                                 current->timer_slack_ns = arg2;
1735                         break;
1736                 default:
1737                         error = -EINVAL;
1738                         break;
1739         }
1740         return error;
1741 }
1742
1743 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1744                            struct getcpu_cache __user *unused)
1745 {
1746         int err = 0;
1747         int cpu = raw_smp_processor_id();
1748         if (cpup)
1749                 err |= put_user(cpu, cpup);
1750         if (nodep)
1751                 err |= put_user(cpu_to_node(cpu), nodep);
1752         return err ? -EFAULT : 0;
1753 }
1754
1755 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1756
1757 static void argv_cleanup(char **argv, char **envp)
1758 {
1759         argv_free(argv);
1760 }
1761
1762 /**
1763  * orderly_poweroff - Trigger an orderly system poweroff
1764  * @force: force poweroff if command execution fails
1765  *
1766  * This may be called from any context to trigger a system shutdown.
1767  * If the orderly shutdown fails, it will force an immediate shutdown.
1768  */
1769 int orderly_poweroff(bool force)
1770 {
1771         int argc;
1772         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1773         static char *envp[] = {
1774                 "HOME=/",
1775                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1776                 NULL
1777         };
1778         int ret = -ENOMEM;
1779         struct subprocess_info *info;
1780
1781         if (argv == NULL) {
1782                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1783                        __func__, poweroff_cmd);
1784                 goto out;
1785         }
1786
1787         info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC);
1788         if (info == NULL) {
1789                 argv_free(argv);
1790                 goto out;
1791         }
1792
1793         call_usermodehelper_setcleanup(info, argv_cleanup);
1794
1795         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1796
1797   out:
1798         if (ret && force) {
1799                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1800                        "forcing the issue\n");
1801
1802                 /* I guess this should try to kick off some daemon to
1803                    sync and poweroff asap.  Or not even bother syncing
1804                    if we're doing an emergency shutdown? */
1805                 emergency_sync();
1806                 kernel_power_off();
1807         }
1808
1809         return ret;
1810 }
1811 EXPORT_SYMBOL_GPL(orderly_poweroff);