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   1 /*
   2  *  linux/kernel/sys.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/config.h>
   8 #include <linux/module.h>
   9 #include <linux/mm.h>
  10 #include <linux/utsname.h>
  11 #include <linux/mman.h>
  12 #include <linux/smp_lock.h>
  13 #include <linux/notifier.h>
  14 #include <linux/reboot.h>
  15 #include <linux/prctl.h>
  16 #include <linux/init.h>
  17 #include <linux/highuid.h>
  18 #include <linux/fs.h>
  19 #include <linux/workqueue.h>
  20 #include <linux/device.h>
  21 #include <linux/key.h>
  22 #include <linux/times.h>
  23 #include <linux/posix-timers.h>
  24 #include <linux/security.h>
  25 #include <linux/dcookies.h>
  26 #include <linux/suspend.h>
  27 #include <linux/tty.h>
  28 #include <linux/signal.h>
  29
  30 #include <linux/compat.h>
  31 #include <linux/syscalls.h>
  32
  33 #include <asm/uaccess.h>
  34 #include <asm/io.h>
  35 #include <asm/unistd.h>
  36
  37 #ifndef SET_UNALIGN_CTL
  38 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  39 #endif
  40 #ifndef GET_UNALIGN_CTL
  41 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  42 #endif
  43 #ifndef SET_FPEMU_CTL
  44 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  45 #endif
  46 #ifndef GET_FPEMU_CTL
  47 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  48 #endif
  49 #ifndef SET_FPEXC_CTL
  50 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  51 #endif
  52 #ifndef GET_FPEXC_CTL
  53 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  54 #endif
  55
  56 /*
  57  * this is where the system-wide overflow UID and GID are defined, for
  58  * architectures that now have 32-bit UID/GID but didn't in the past
  59  */
  60
  61 int overflowuid = DEFAULT_OVERFLOWUID;
  62 int overflowgid = DEFAULT_OVERFLOWGID;
  63
  64 #ifdef CONFIG_UID16
  65 EXPORT_SYMBOL(overflowuid);
  66 EXPORT_SYMBOL(overflowgid);
  67 #endif
  68
  69 /*
  70  * the same as above, but for filesystems which can only store a 16-bit
  71  * UID and GID. as such, this is needed on all architectures
  72  */
  73
  74 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  75 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
  76
  77 EXPORT_SYMBOL(fs_overflowuid);
  78 EXPORT_SYMBOL(fs_overflowgid);
  79
  80 /*
  81  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
  82  */
  83
  84 int C_A_D = 1;
  85 int cad_pid = 1;
  86
  87 /*
  88  *      Notifier list for kernel code which wants to be called
  89  *      at shutdown. This is used to stop any idling DMA operations
  90  *      and the like.
  91  */
  92
  93 static struct notifier_block *reboot_notifier_list;
  94 static DEFINE_RWLOCK(notifier_lock);
  95
  96 /**
  97  *      notifier_chain_register - Add notifier to a notifier chain
  98  *      @list: Pointer to root list pointer
  99  *      @n: New entry in notifier chain
 100  *
 101  *      Adds a notifier to a notifier chain.
 102  *
 103  *      Currently always returns zero.
 104  */
 105
 106 int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
 107 {
 108         write_lock(&notifier_lock);
 109         while(*list)
 110         {
 111                 if(n->priority > (*list)->priority)
 112                         break;
 113                 list= &((*list)->next);
 114         }
 115         n->next = *list;
 116         *list=n;
 117         write_unlock(&notifier_lock);
 118         return 0;
 119 }
 120
 121 EXPORT_SYMBOL(notifier_chain_register);
 122
 123 /**
 124  *      notifier_chain_unregister - Remove notifier from a notifier chain
 125  *      @nl: Pointer to root list pointer
 126  *      @n: New entry in notifier chain
 127  *
 128  *      Removes a notifier from a notifier chain.
 129  *
 130  *      Returns zero on success, or %-ENOENT on failure.
 131  */
 132
 133 int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
 134 {
 135         write_lock(&notifier_lock);
 136         while((*nl)!=NULL)
 137         {
 138                 if((*nl)==n)
 139                 {
 140                         *nl=n->next;
 141                         write_unlock(&notifier_lock);
 142                         return 0;
 143                 }
 144                 nl=&((*nl)->next);
 145         }
 146         write_unlock(&notifier_lock);
 147         return -ENOENT;
 148 }
 149
 150 EXPORT_SYMBOL(notifier_chain_unregister);
 151
 152 /**
 153  *      notifier_call_chain - Call functions in a notifier chain
 154  *      @n: Pointer to root pointer of notifier chain
 155  *      @val: Value passed unmodified to notifier function
 156  *      @v: Pointer passed unmodified to notifier function
 157  *
 158  *      Calls each function in a notifier chain in turn.
 159  *
 160  *      If the return value of the notifier can be and'd
 161  *      with %NOTIFY_STOP_MASK, then notifier_call_chain
 162  *      will return immediately, with the return value of
 163  *      the notifier function which halted execution.
 164  *      Otherwise, the return value is the return value
 165  *      of the last notifier function called.
 166  */
 167
 168 int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
 169 {
 170         int ret=NOTIFY_DONE;
 171         struct notifier_block *nb = *n;
 172
 173         while(nb)
 174         {
 175                 ret=nb->notifier_call(nb,val,v);
 176                 if(ret&NOTIFY_STOP_MASK)
 177                 {
 178                         return ret;
 179                 }
 180                 nb=nb->next;
 181         }
 182         return ret;
 183 }
 184
 185 EXPORT_SYMBOL(notifier_call_chain);
 186
 187 /**
 188  *      register_reboot_notifier - Register function to be called at reboot time
 189  *      @nb: Info about notifier function to be called
 190  *
 191  *      Registers a function with the list of functions
 192  *      to be called at reboot time.
 193  *
 194  *      Currently always returns zero, as notifier_chain_register
 195  *      always returns zero.
 196  */
 197
 198 int register_reboot_notifier(struct notifier_block * nb)
 199 {
 200         return notifier_chain_register(&reboot_notifier_list, nb);
 201 }
 202
 203 EXPORT_SYMBOL(register_reboot_notifier);
 204
 205 /**
 206  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
 207  *      @nb: Hook to be unregistered
 208  *
 209  *      Unregisters a previously registered reboot
 210  *      notifier function.
 211  *
 212  *      Returns zero on success, or %-ENOENT on failure.
 213  */
 214
 215 int unregister_reboot_notifier(struct notifier_block * nb)
 216 {
 217         return notifier_chain_unregister(&reboot_notifier_list, nb);
 218 }
 219
 220 EXPORT_SYMBOL(unregister_reboot_notifier);
 221
 222 static int set_one_prio(struct task_struct *p, int niceval, int error)
 223 {
 224         int no_nice;
 225
 226         if (p->uid != current->euid &&
 227                 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
 228                 error = -EPERM;
 229                 goto out;
 230         }
 231         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 232                 error = -EACCES;
 233                 goto out;
 234         }
 235         no_nice = security_task_setnice(p, niceval);
 236         if (no_nice) {
 237                 error = no_nice;
 238                 goto out;
 239         }
 240         if (error == -ESRCH)
 241                 error = 0;
 242         set_user_nice(p, niceval);
 243 out:
 244         return error;
 245 }
 246
 247 asmlinkage long sys_setpriority(int which, int who, int niceval)
 248 {
 249         struct task_struct *g, *p;
 250         struct user_struct *user;
 251         int error = -EINVAL;
 252
 253         if (which > 2 || which < 0)
 254                 goto out;
 255
 256         /* normalize: avoid signed division (rounding problems) */
 257         error = -ESRCH;
 258         if (niceval < -20)
 259                 niceval = -20;
 260         if (niceval > 19)
 261                 niceval = 19;
 262
 263         read_lock(&tasklist_lock);
 264         switch (which) {
 265                 case PRIO_PROCESS:
 266                         if (!who)
 267                                 who = current->pid;
 268                         p = find_task_by_pid(who);
 269                         if (p)
 270                                 error = set_one_prio(p, niceval, error);
 271                         break;
 272                 case PRIO_PGRP:
 273                         if (!who)
 274                                 who = process_group(current);
 275                         do_each_task_pid(who, PIDTYPE_PGID, p) {
 276                                 error = set_one_prio(p, niceval, error);
 277                         } while_each_task_pid(who, PIDTYPE_PGID, p);
 278                         break;
 279                 case PRIO_USER:
 280                         user = current->user;
 281                         if (!who)
 282                                 who = current->uid;
 283                         else
 284                                 if ((who != current->uid) && !(user = find_user(who)))
 285                                         goto out_unlock;        /* No processes for this user */
 286
 287                         do_each_thread(g, p)
 288                                 if (p->uid == who)
 289                                         error = set_one_prio(p, niceval, error);
 290                         while_each_thread(g, p);
 291                         if (who != current->uid)
 292                                 free_uid(user);         /* For find_user() */
 293                         break;
 294         }
 295 out_unlock:
 296         read_unlock(&tasklist_lock);
 297 out:
 298         return error;
 299 }
 300
 301 /*
 302  * Ugh. To avoid negative return values, "getpriority()" will
 303  * not return the normal nice-value, but a negated value that
 304  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 305  * to stay compatible.
 306  */
 307 asmlinkage long sys_getpriority(int which, int who)
 308 {
 309         struct task_struct *g, *p;
 310         struct user_struct *user;
 311         long niceval, retval = -ESRCH;
 312
 313         if (which > 2 || which < 0)
 314                 return -EINVAL;
 315
 316         read_lock(&tasklist_lock);
 317         switch (which) {
 318                 case PRIO_PROCESS:
 319                         if (!who)
 320                                 who = current->pid;
 321                         p = find_task_by_pid(who);
 322                         if (p) {
 323                                 niceval = 20 - task_nice(p);
 324                                 if (niceval > retval)
 325                                         retval = niceval;
 326                         }
 327                         break;
 328                 case PRIO_PGRP:
 329                         if (!who)
 330                                 who = process_group(current);
 331                         do_each_task_pid(who, PIDTYPE_PGID, p) {
 332                                 niceval = 20 - task_nice(p);
 333                                 if (niceval > retval)
 334                                         retval = niceval;
 335                         } while_each_task_pid(who, PIDTYPE_PGID, p);
 336                         break;
 337                 case PRIO_USER:
 338                         user = current->user;
 339                         if (!who)
 340                                 who = current->uid;
 341                         else
 342                                 if ((who != current->uid) && !(user = find_user(who)))
 343                                         goto out_unlock;        /* No processes for this user */
 344
 345                         do_each_thread(g, p)
 346                                 if (p->uid == who) {
 347                                         niceval = 20 - task_nice(p);
 348                                         if (niceval > retval)
 349                                                 retval = niceval;
 350                                 }
 351                         while_each_thread(g, p);
 352                         if (who != current->uid)
 353                                 free_uid(user);         /* for find_user() */
 354                         break;
 355         }
 356 out_unlock:
 357         read_unlock(&tasklist_lock);
 358
 359         return retval;
 360 }
 361
 362
 363 /*
 364  * Reboot system call: for obvious reasons only root may call it,
 365  * and even root needs to set up some magic numbers in the registers
 366  * so that some mistake won't make this reboot the whole machine.
 367  * You can also set the meaning of the ctrl-alt-del-key here.
 368  *
 369  * reboot doesn't sync: do that yourself before calling this.
 370  */
 371 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
 372 {
 373         char buffer[256];
 374
 375         /* We only trust the superuser with rebooting the system. */
 376         if (!capable(CAP_SYS_BOOT))
 377                 return -EPERM;
 378
 379         /* For safety, we require "magic" arguments. */
 380         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 381             (magic2 != LINUX_REBOOT_MAGIC2 &&
 382                         magic2 != LINUX_REBOOT_MAGIC2A &&
 383                         magic2 != LINUX_REBOOT_MAGIC2B &&
 384                         magic2 != LINUX_REBOOT_MAGIC2C))
 385                 return -EINVAL;
 386
 387         lock_kernel();
 388         switch (cmd) {
 389         case LINUX_REBOOT_CMD_RESTART:
 390                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
 391                 system_state = SYSTEM_RESTART;
 392                 device_shutdown();
 393                 printk(KERN_EMERG "Restarting system.\n");
 394                 machine_restart(NULL);
 395                 break;
 396
 397         case LINUX_REBOOT_CMD_CAD_ON:
 398                 C_A_D = 1;
 399                 break;
 400
 401         case LINUX_REBOOT_CMD_CAD_OFF:
 402                 C_A_D = 0;
 403                 break;
 404
 405         case LINUX_REBOOT_CMD_HALT:
 406                 notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
 407                 system_state = SYSTEM_HALT;
 408                 device_suspend(PMSG_SUSPEND);
 409                 device_shutdown();
 410                 printk(KERN_EMERG "System halted.\n");
 411                 machine_halt();
 412                 unlock_kernel();
 413                 do_exit(0);
 414                 break;
 415
 416         case LINUX_REBOOT_CMD_POWER_OFF:
 417                 notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
 418                 system_state = SYSTEM_POWER_OFF;
 419                 device_suspend(PMSG_SUSPEND);
 420                 device_shutdown();
 421                 printk(KERN_EMERG "Power down.\n");
 422                 machine_power_off();
 423                 unlock_kernel();
 424                 do_exit(0);
 425                 break;
 426
 427         case LINUX_REBOOT_CMD_RESTART2:
 428                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 429                         unlock_kernel();
 430                         return -EFAULT;
 431                 }
 432                 buffer[sizeof(buffer) - 1] = '\0';
 433
 434                 notifier_call_chain(&reboot_notifier_list, SYS_RESTART, buffer);
 435                 system_state = SYSTEM_RESTART;
 436                 device_suspend(PMSG_FREEZE);
 437                 device_shutdown();
 438                 printk(KERN_EMERG "Restarting system with command '%s'.\n", buffer);
 439                 machine_restart(buffer);
 440                 break;
 441
 442 #ifdef CONFIG_SOFTWARE_SUSPEND
 443         case LINUX_REBOOT_CMD_SW_SUSPEND:
 444                 {
 445                         int ret = software_suspend();
 446                         unlock_kernel();
 447                         return ret;
 448                 }
 449 #endif
 450
 451         default:
 452                 unlock_kernel();
 453                 return -EINVAL;
 454         }
 455         unlock_kernel();
 456         return 0;
 457 }
 458
 459 static void deferred_cad(void *dummy)
 460 {
 461         notifier_call_chain(&reboot_notifier_list, SYS_RESTART, NULL);
 462         machine_restart(NULL);
 463 }
 464
 465 /*
 466  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 467  * As it's called within an interrupt, it may NOT sync: the only choice
 468  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 469  */
 470 void ctrl_alt_del(void)
 471 {
 472         static DECLARE_WORK(cad_work, deferred_cad, NULL);
 473
 474         if (C_A_D)
 475                 schedule_work(&cad_work);
 476         else
 477                 kill_proc(cad_pid, SIGINT, 1);
 478 }
 479
 480
 481 /*
 482  * Unprivileged users may change the real gid to the effective gid
 483  * or vice versa.  (BSD-style)
 484  *
 485  * If you set the real gid at all, or set the effective gid to a value not
 486  * equal to the real gid, then the saved gid is set to the new effective gid.
 487  *
 488  * This makes it possible for a setgid program to completely drop its
 489  * privileges, which is often a useful assertion to make when you are doing
 490  * a security audit over a program.
 491  *
 492  * The general idea is that a program which uses just setregid() will be
 493  * 100% compatible with BSD.  A program which uses just setgid() will be
 494  * 100% compatible with POSIX with saved IDs.
 495  *
 496  * SMP: There are not races, the GIDs are checked only by filesystem
 497  *      operations (as far as semantic preservation is concerned).
 498  */
 499 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
 500 {
 501         int old_rgid = current->gid;
 502         int old_egid = current->egid;
 503         int new_rgid = old_rgid;
 504         int new_egid = old_egid;
 505         int retval;
 506
 507         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 508         if (retval)
 509                 return retval;
 510
 511         if (rgid != (gid_t) -1) {
 512                 if ((old_rgid == rgid) ||
 513                     (current->egid==rgid) ||
 514                     capable(CAP_SETGID))
 515                         new_rgid = rgid;
 516                 else
 517                         return -EPERM;
 518         }
 519         if (egid != (gid_t) -1) {
 520                 if ((old_rgid == egid) ||
 521                     (current->egid == egid) ||
 522                     (current->sgid == egid) ||
 523                     capable(CAP_SETGID))
 524                         new_egid = egid;
 525                 else {
 526                         return -EPERM;
 527                 }
 528         }
 529         if (new_egid != old_egid)
 530         {
 531                 current->mm->dumpable = suid_dumpable;
 532                 smp_wmb();
 533         }
 534         if (rgid != (gid_t) -1 ||
 535             (egid != (gid_t) -1 && egid != old_rgid))
 536                 current->sgid = new_egid;
 537         current->fsgid = new_egid;
 538         current->egid = new_egid;
 539         current->gid = new_rgid;
 540         key_fsgid_changed(current);
 541         return 0;
 542 }
 543
 544 /*
 545  * setgid() is implemented like SysV w/ SAVED_IDS
 546  *
 547  * SMP: Same implicit races as above.
 548  */
 549 asmlinkage long sys_setgid(gid_t gid)
 550 {
 551         int old_egid = current->egid;
 552         int retval;
 553
 554         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 555         if (retval)
 556                 return retval;
 557
 558         if (capable(CAP_SETGID))
 559         {
 560                 if(old_egid != gid)
 561                 {
 562                         current->mm->dumpable = suid_dumpable;
 563                         smp_wmb();
 564                 }
 565                 current->gid = current->egid = current->sgid = current->fsgid = gid;
 566         }
 567         else if ((gid == current->gid) || (gid == current->sgid))
 568         {
 569                 if(old_egid != gid)
 570                 {
 571                         current->mm->dumpable = suid_dumpable;
 572                         smp_wmb();
 573                 }
 574                 current->egid = current->fsgid = gid;
 575         }
 576         else
 577                 return -EPERM;
 578
 579         key_fsgid_changed(current);
 580         return 0;
 581 }
 582
 583 static int set_user(uid_t new_ruid, int dumpclear)
 584 {
 585         struct user_struct *new_user;
 586
 587         new_user = alloc_uid(new_ruid);
 588         if (!new_user)
 589                 return -EAGAIN;
 590
 591         if (atomic_read(&new_user->processes) >=
 592                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 593                         new_user != &root_user) {
 594                 free_uid(new_user);
 595                 return -EAGAIN;
 596         }
 597
 598         switch_uid(new_user);
 599
 600         if(dumpclear)
 601         {
 602                 current->mm->dumpable = suid_dumpable;
 603                 smp_wmb();
 604         }
 605         current->uid = new_ruid;
 606         return 0;
 607 }
 608
 609 /*
 610  * Unprivileged users may change the real uid to the effective uid
 611  * or vice versa.  (BSD-style)
 612  *
 613  * If you set the real uid at all, or set the effective uid to a value not
 614  * equal to the real uid, then the saved uid is set to the new effective uid.
 615  *
 616  * This makes it possible for a setuid program to completely drop its
 617  * privileges, which is often a useful assertion to make when you are doing
 618  * a security audit over a program.
 619  *
 620  * The general idea is that a program which uses just setreuid() will be
 621  * 100% compatible with BSD.  A program which uses just setuid() will be
 622  * 100% compatible with POSIX with saved IDs.
 623  */
 624 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 625 {
 626         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
 627         int retval;
 628
 629         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 630         if (retval)
 631                 return retval;
 632
 633         new_ruid = old_ruid = current->uid;
 634         new_euid = old_euid = current->euid;
 635         old_suid = current->suid;
 636
 637         if (ruid != (uid_t) -1) {
 638                 new_ruid = ruid;
 639                 if ((old_ruid != ruid) &&
 640                     (current->euid != ruid) &&
 641                     !capable(CAP_SETUID))
 642                         return -EPERM;
 643         }
 644
 645         if (euid != (uid_t) -1) {
 646                 new_euid = euid;
 647                 if ((old_ruid != euid) &&
 648                     (current->euid != euid) &&
 649                     (current->suid != euid) &&
 650                     !capable(CAP_SETUID))
 651                         return -EPERM;
 652         }
 653
 654         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
 655                 return -EAGAIN;
 656
 657         if (new_euid != old_euid)
 658         {
 659                 current->mm->dumpable = suid_dumpable;
 660                 smp_wmb();
 661         }
 662         current->fsuid = current->euid = new_euid;
 663         if (ruid != (uid_t) -1 ||
 664             (euid != (uid_t) -1 && euid != old_ruid))
 665                 current->suid = current->euid;
 666         current->fsuid = current->euid;
 667
 668         key_fsuid_changed(current);
 669
 670         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
 671 }
 672
 673
 674
 675 /*
 676  * setuid() is implemented like SysV with SAVED_IDS
 677  *
 678  * Note that SAVED_ID's is deficient in that a setuid root program
 679  * like sendmail, for example, cannot set its uid to be a normal
 680  * user and then switch back, because if you're root, setuid() sets
 681  * the saved uid too.  If you don't like this, blame the bright people
 682  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 683  * will allow a root program to temporarily drop privileges and be able to
 684  * regain them by swapping the real and effective uid.
 685  */
 686 asmlinkage long sys_setuid(uid_t uid)
 687 {
 688         int old_euid = current->euid;
 689         int old_ruid, old_suid, new_ruid, new_suid;
 690         int retval;
 691
 692         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 693         if (retval)
 694                 return retval;
 695
 696         old_ruid = new_ruid = current->uid;
 697         old_suid = current->suid;
 698         new_suid = old_suid;
 699
 700         if (capable(CAP_SETUID)) {
 701                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
 702                         return -EAGAIN;
 703                 new_suid = uid;
 704         } else if ((uid != current->uid) && (uid != new_suid))
 705                 return -EPERM;
 706
 707         if (old_euid != uid)
 708         {
 709                 current->mm->dumpable = suid_dumpable;
 710                 smp_wmb();
 711         }
 712         current->fsuid = current->euid = uid;
 713         current->suid = new_suid;
 714
 715         key_fsuid_changed(current);
 716
 717         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
 718 }
 719
 720
 721 /*
 722  * This function implements a generic ability to update ruid, euid,
 723  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 724  */
 725 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 726 {
 727         int old_ruid = current->uid;
 728         int old_euid = current->euid;
 729         int old_suid = current->suid;
 730         int retval;
 731
 732         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 733         if (retval)
 734                 return retval;
 735
 736         if (!capable(CAP_SETUID)) {
 737                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
 738                     (ruid != current->euid) && (ruid != current->suid))
 739                         return -EPERM;
 740                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
 741                     (euid != current->euid) && (euid != current->suid))
 742                         return -EPERM;
 743                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
 744                     (suid != current->euid) && (suid != current->suid))
 745                         return -EPERM;
 746         }
 747         if (ruid != (uid_t) -1) {
 748                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
 749                         return -EAGAIN;
 750         }
 751         if (euid != (uid_t) -1) {
 752                 if (euid != current->euid)
 753                 {
 754                         current->mm->dumpable = suid_dumpable;
 755                         smp_wmb();
 756                 }
 757                 current->euid = euid;
 758         }
 759         current->fsuid = current->euid;
 760         if (suid != (uid_t) -1)
 761                 current->suid = suid;
 762
 763         key_fsuid_changed(current);
 764
 765         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
 766 }
 767
 768 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
 769 {
 770         int retval;
 771
 772         if (!(retval = put_user(current->uid, ruid)) &&
 773             !(retval = put_user(current->euid, euid)))
 774                 retval = put_user(current->suid, suid);
 775
 776         return retval;
 777 }
 778
 779 /*
 780  * Same as above, but for rgid, egid, sgid.
 781  */
 782 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 783 {
 784         int retval;
 785
 786         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 787         if (retval)
 788                 return retval;
 789
 790         if (!capable(CAP_SETGID)) {
 791                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
 792                     (rgid != current->egid) && (rgid != current->sgid))
 793                         return -EPERM;
 794                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
 795                     (egid != current->egid) && (egid != current->sgid))
 796                         return -EPERM;
 797                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
 798                     (sgid != current->egid) && (sgid != current->sgid))
 799                         return -EPERM;
 800         }
 801         if (egid != (gid_t) -1) {
 802                 if (egid != current->egid)
 803                 {
 804                         current->mm->dumpable = suid_dumpable;
 805                         smp_wmb();
 806                 }
 807                 current->egid = egid;
 808         }
 809         current->fsgid = current->egid;
 810         if (rgid != (gid_t) -1)
 811                 current->gid = rgid;
 812         if (sgid != (gid_t) -1)
 813                 current->sgid = sgid;
 814
 815         key_fsgid_changed(current);
 816         return 0;
 817 }
 818
 819 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
 820 {
 821         int retval;
 822
 823         if (!(retval = put_user(current->gid, rgid)) &&
 824             !(retval = put_user(current->egid, egid)))
 825                 retval = put_user(current->sgid, sgid);
 826
 827         return retval;
 828 }
 829
 830
 831 /*
 832  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 833  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 834  * whatever uid it wants to). It normally shadows "euid", except when
 835  * explicitly set by setfsuid() or for access..
 836  */
 837 asmlinkage long sys_setfsuid(uid_t uid)
 838 {
 839         int old_fsuid;
 840
 841         old_fsuid = current->fsuid;
 842         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
 843                 return old_fsuid;
 844
 845         if (uid == current->uid || uid == current->euid ||
 846             uid == current->suid || uid == current->fsuid ||
 847             capable(CAP_SETUID))
 848         {
 849                 if (uid != old_fsuid)
 850                 {
 851                         current->mm->dumpable = suid_dumpable;
 852                         smp_wmb();
 853                 }
 854                 current->fsuid = uid;
 855         }
 856
 857         key_fsuid_changed(current);
 858
 859         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
 860
 861         return old_fsuid;
 862 }
 863
 864 /*
 865  * Samma på svenska..
 866  */
 867 asmlinkage long sys_setfsgid(gid_t gid)
 868 {
 869         int old_fsgid;
 870
 871         old_fsgid = current->fsgid;
 872         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 873                 return old_fsgid;
 874
 875         if (gid == current->gid || gid == current->egid ||
 876             gid == current->sgid || gid == current->fsgid ||
 877             capable(CAP_SETGID))
 878         {
 879                 if (gid != old_fsgid)
 880                 {
 881                         current->mm->dumpable = suid_dumpable;
 882                         smp_wmb();
 883                 }
 884                 current->fsgid = gid;
 885                 key_fsgid_changed(current);
 886         }
 887         return old_fsgid;
 888 }
 889
 890 asmlinkage long sys_times(struct tms __user * tbuf)
 891 {
 892         /*
 893          *      In the SMP world we might just be unlucky and have one of
 894          *      the times increment as we use it. Since the value is an
 895          *      atomically safe type this is just fine. Conceptually its
 896          *      as if the syscall took an instant longer to occur.
 897          */
 898         if (tbuf) {
 899                 struct tms tmp;
 900                 cputime_t utime, stime, cutime, cstime;
 901
 902 #ifdef CONFIG_SMP
 903                 if (thread_group_empty(current)) {
 904                         /*
 905                          * Single thread case without the use of any locks.
 906                          *
 907                          * We may race with release_task if two threads are
 908                          * executing. However, release task first adds up the
 909                          * counters (__exit_signal) before  removing the task
 910                          * from the process tasklist (__unhash_process).
 911                          * __exit_signal also acquires and releases the
 912                          * siglock which results in the proper memory ordering
 913                          * so that the list modifications are always visible
 914                          * after the counters have been updated.
 915                          *
 916                          * If the counters have been updated by the second thread
 917                          * but the thread has not yet been removed from the list
 918                          * then the other branch will be executing which will
 919                          * block on tasklist_lock until the exit handling of the
 920                          * other task is finished.
 921                          *
 922                          * This also implies that the sighand->siglock cannot
 923                          * be held by another processor. So we can also
 924                          * skip acquiring that lock.
 925                          */
 926                         utime = cputime_add(current->signal->utime, current->utime);
 927                         stime = cputime_add(current->signal->utime, current->stime);
 928                         cutime = current->signal->cutime;
 929                         cstime = current->signal->cstime;
 930                 } else
 931 #endif
 932                 {
 933
 934                         /* Process with multiple threads */
 935                         struct task_struct *tsk = current;
 936                         struct task_struct *t;
 937
 938                         read_lock(&tasklist_lock);
 939                         utime = tsk->signal->utime;
 940                         stime = tsk->signal->stime;
 941                         t = tsk;
 942                         do {
 943                                 utime = cputime_add(utime, t->utime);
 944                                 stime = cputime_add(stime, t->stime);
 945                                 t = next_thread(t);
 946                         } while (t != tsk);
 947
 948                         /*
 949                          * While we have tasklist_lock read-locked, no dying thread
 950                          * can be updating current->signal->[us]time.  Instead,
 951                          * we got their counts included in the live thread loop.
 952                          * However, another thread can come in right now and
 953                          * do a wait call that updates current->signal->c[us]time.
 954                          * To make sure we always see that pair updated atomically,
 955                          * we take the siglock around fetching them.
 956                          */
 957                         spin_lock_irq(&tsk->sighand->siglock);
 958                         cutime = tsk->signal->cutime;
 959                         cstime = tsk->signal->cstime;
 960                         spin_unlock_irq(&tsk->sighand->siglock);
 961                         read_unlock(&tasklist_lock);
 962                 }
 963                 tmp.tms_utime = cputime_to_clock_t(utime);
 964                 tmp.tms_stime = cputime_to_clock_t(stime);
 965                 tmp.tms_cutime = cputime_to_clock_t(cutime);
 966                 tmp.tms_cstime = cputime_to_clock_t(cstime);
 967                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 968                         return -EFAULT;
 969         }
 970         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 971 }
 972
 973 /*
 974  * This needs some heavy checking ...
 975  * I just haven't the stomach for it. I also don't fully
 976  * understand sessions/pgrp etc. Let somebody who does explain it.
 977  *
 978  * OK, I think I have the protection semantics right.... this is really
 979  * only important on a multi-user system anyway, to make sure one user
 980  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 981  *
 982  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 983  * LBT 04.03.94
 984  */
 985
 986 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 987 {
 988         struct task_struct *p;
 989         int err = -EINVAL;
 990
 991         if (!pid)
 992                 pid = current->pid;
 993         if (!pgid)
 994                 pgid = pid;
 995         if (pgid < 0)
 996                 return -EINVAL;
 997
 998         /* From this point forward we keep holding onto the tasklist lock
 999          * so that our parent does not change from under us. -DaveM
1000          */
1001         write_lock_irq(&tasklist_lock);
1002
1003         err = -ESRCH;
1004         p = find_task_by_pid(pid);
1005         if (!p)
1006                 goto out;
1007
1008         err = -EINVAL;
1009         if (!thread_group_leader(p))
1010                 goto out;
1011
1012         if (p->parent == current || p->real_parent == current) {
1013                 err = -EPERM;
1014                 if (p->signal->session != current->signal->session)
1015                         goto out;
1016                 err = -EACCES;
1017                 if (p->did_exec)
1018                         goto out;
1019         } else {
1020                 err = -ESRCH;
1021                 if (p != current)
1022                         goto out;
1023         }
1024
1025         err = -EPERM;
1026         if (p->signal->leader)
1027                 goto out;
1028
1029         if (pgid != pid) {
1030                 struct task_struct *p;
1031
1032                 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
1033                         if (p->signal->session == current->signal->session)
1034                                 goto ok_pgid;
1035                 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1036                 goto out;
1037         }
1038
1039 ok_pgid:
1040         err = security_task_setpgid(p, pgid);
1041         if (err)
1042                 goto out;
1043
1044         if (process_group(p) != pgid) {
1045                 detach_pid(p, PIDTYPE_PGID);
1046                 p->signal->pgrp = pgid;
1047                 attach_pid(p, PIDTYPE_PGID, pgid);
1048         }
1049
1050         err = 0;
1051 out:
1052         /* All paths lead to here, thus we are safe. -DaveM */
1053         write_unlock_irq(&tasklist_lock);
1054         return err;
1055 }
1056
1057 asmlinkage long sys_getpgid(pid_t pid)
1058 {
1059         if (!pid) {
1060                 return process_group(current);
1061         } else {
1062                 int retval;
1063                 struct task_struct *p;
1064
1065                 read_lock(&tasklist_lock);
1066                 p = find_task_by_pid(pid);
1067
1068                 retval = -ESRCH;
1069                 if (p) {
1070                         retval = security_task_getpgid(p);
1071                         if (!retval)
1072                                 retval = process_group(p);
1073                 }
1074                 read_unlock(&tasklist_lock);
1075                 return retval;
1076         }
1077 }
1078
1079 #ifdef __ARCH_WANT_SYS_GETPGRP
1080
1081 asmlinkage long sys_getpgrp(void)
1082 {
1083         /* SMP - assuming writes are word atomic this is fine */
1084         return process_group(current);
1085 }
1086
1087 #endif
1088
1089 asmlinkage long sys_getsid(pid_t pid)
1090 {
1091         if (!pid) {
1092                 return current->signal->session;
1093         } else {
1094                 int retval;
1095                 struct task_struct *p;
1096
1097                 read_lock(&tasklist_lock);
1098                 p = find_task_by_pid(pid);
1099
1100                 retval = -ESRCH;
1101                 if(p) {
1102                         retval = security_task_getsid(p);
1103                         if (!retval)
1104                                 retval = p->signal->session;
1105                 }
1106                 read_unlock(&tasklist_lock);
1107                 return retval;
1108         }
1109 }
1110
1111 asmlinkage long sys_setsid(void)
1112 {
1113         struct pid *pid;
1114         int err = -EPERM;
1115
1116         if (!thread_group_leader(current))
1117                 return -EINVAL;
1118
1119         down(&tty_sem);
1120         write_lock_irq(&tasklist_lock);
1121
1122         pid = find_pid(PIDTYPE_PGID, current->pid);
1123         if (pid)
1124                 goto out;
1125
1126         current->signal->leader = 1;
1127         __set_special_pids(current->pid, current->pid);
1128         current->signal->tty = NULL;
1129         current->signal->tty_old_pgrp = 0;
1130         err = process_group(current);
1131 out:
1132         write_unlock_irq(&tasklist_lock);
1133         up(&tty_sem);
1134         return err;
1135 }
1136
1137 /*
1138  * Supplementary group IDs
1139  */
1140
1141 /* init to 2 - one for init_task, one to ensure it is never freed */
1142 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1143
1144 struct group_info *groups_alloc(int gidsetsize)
1145 {
1146         struct group_info *group_info;
1147         int nblocks;
1148         int i;
1149
1150         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1151         /* Make sure we always allocate at least one indirect block pointer */
1152         nblocks = nblocks ? : 1;
1153         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1154         if (!group_info)
1155                 return NULL;
1156         group_info->ngroups = gidsetsize;
1157         group_info->nblocks = nblocks;
1158         atomic_set(&group_info->usage, 1);
1159
1160         if (gidsetsize <= NGROUPS_SMALL) {
1161                 group_info->blocks[0] = group_info->small_block;
1162         } else {
1163                 for (i = 0; i < nblocks; i++) {
1164                         gid_t *b;
1165                         b = (void *)__get_free_page(GFP_USER);
1166                         if (!b)
1167                                 goto out_undo_partial_alloc;
1168                         group_info->blocks[i] = b;
1169                 }
1170         }
1171         return group_info;
1172
1173 out_undo_partial_alloc:
1174         while (--i >= 0) {
1175                 free_page((unsigned long)group_info->blocks[i]);
1176         }
1177         kfree(group_info);
1178         return NULL;
1179 }
1180
1181 EXPORT_SYMBOL(groups_alloc);
1182
1183 void groups_free(struct group_info *group_info)
1184 {
1185         if (group_info->blocks[0] != group_info->small_block) {
1186                 int i;
1187                 for (i = 0; i < group_info->nblocks; i++)
1188                         free_page((unsigned long)group_info->blocks[i]);
1189         }
1190         kfree(group_info);
1191 }
1192
1193 EXPORT_SYMBOL(groups_free);
1194
1195 /* export the group_info to a user-space array */
1196 static int groups_to_user(gid_t __user *grouplist,
1197     struct group_info *group_info)
1198 {
1199         int i;
1200         int count = group_info->ngroups;
1201
1202         for (i = 0; i < group_info->nblocks; i++) {
1203                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1204                 int off = i * NGROUPS_PER_BLOCK;
1205                 int len = cp_count * sizeof(*grouplist);
1206
1207                 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1208                         return -EFAULT;
1209
1210                 count -= cp_count;
1211         }
1212         return 0;
1213 }
1214
1215 /* fill a group_info from a user-space array - it must be allocated already */
1216 static int groups_from_user(struct group_info *group_info,
1217     gid_t __user *grouplist)
1218  {
1219         int i;
1220         int count = group_info->ngroups;
1221
1222         for (i = 0; i < group_info->nblocks; i++) {
1223                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1224                 int off = i * NGROUPS_PER_BLOCK;
1225                 int len = cp_count * sizeof(*grouplist);
1226
1227                 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1228                         return -EFAULT;
1229
1230                 count -= cp_count;
1231         }
1232         return 0;
1233 }
1234
1235 /* a simple Shell sort */
1236 static void groups_sort(struct group_info *group_info)
1237 {
1238         int base, max, stride;
1239         int gidsetsize = group_info->ngroups;
1240
1241         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1242                 ; /* nothing */
1243         stride /= 3;
1244
1245         while (stride) {
1246                 max = gidsetsize - stride;
1247                 for (base = 0; base < max; base++) {
1248                         int left = base;
1249                         int right = left + stride;
1250                         gid_t tmp = GROUP_AT(group_info, right);
1251
1252                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1253                                 GROUP_AT(group_info, right) =
1254                                     GROUP_AT(group_info, left);
1255                                 right = left;
1256                                 left -= stride;
1257                         }
1258                         GROUP_AT(group_info, right) = tmp;
1259                 }
1260                 stride /= 3;
1261         }
1262 }
1263
1264 /* a simple bsearch */
1265 int groups_search(struct group_info *group_info, gid_t grp)
1266 {
1267         int left, right;
1268
1269         if (!group_info)
1270                 return 0;
1271
1272         left = 0;
1273         right = group_info->ngroups;
1274         while (left < right) {
1275                 int mid = (left+right)/2;
1276                 int cmp = grp - GROUP_AT(group_info, mid);
1277                 if (cmp > 0)
1278                         left = mid + 1;
1279                 else if (cmp < 0)
1280                         right = mid;
1281                 else
1282                         return 1;
1283         }
1284         return 0;
1285 }
1286
1287 /* validate and set current->group_info */
1288 int set_current_groups(struct group_info *group_info)
1289 {
1290         int retval;
1291         struct group_info *old_info;
1292
1293         retval = security_task_setgroups(group_info);
1294         if (retval)
1295                 return retval;
1296
1297         groups_sort(group_info);
1298         get_group_info(group_info);
1299
1300         task_lock(current);
1301         old_info = current->group_info;
1302         current->group_info = group_info;
1303         task_unlock(current);
1304
1305         put_group_info(old_info);
1306
1307         return 0;
1308 }
1309
1310 EXPORT_SYMBOL(set_current_groups);
1311
1312 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1313 {
1314         int i = 0;
1315
1316         /*
1317          *      SMP: Nobody else can change our grouplist. Thus we are
1318          *      safe.
1319          */
1320
1321         if (gidsetsize < 0)
1322                 return -EINVAL;
1323
1324         /* no need to grab task_lock here; it cannot change */
1325         get_group_info(current->group_info);
1326         i = current->group_info->ngroups;
1327         if (gidsetsize) {
1328                 if (i > gidsetsize) {
1329                         i = -EINVAL;
1330                         goto out;
1331                 }
1332                 if (groups_to_user(grouplist, current->group_info)) {
1333                         i = -EFAULT;
1334                         goto out;
1335                 }
1336         }
1337 out:
1338         put_group_info(current->group_info);
1339         return i;
1340 }
1341
1342 /*
1343  *      SMP: Our groups are copy-on-write. We can set them safely
1344  *      without another task interfering.
1345  */
1346
1347 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1348 {
1349         struct group_info *group_info;
1350         int retval;
1351
1352         if (!capable(CAP_SETGID))
1353                 return -EPERM;
1354         if ((unsigned)gidsetsize > NGROUPS_MAX)
1355                 return -EINVAL;
1356
1357         group_info = groups_alloc(gidsetsize);
1358         if (!group_info)
1359                 return -ENOMEM;
1360         retval = groups_from_user(group_info, grouplist);
1361         if (retval) {
1362                 put_group_info(group_info);
1363                 return retval;
1364         }
1365
1366         retval = set_current_groups(group_info);
1367         put_group_info(group_info);
1368
1369         return retval;
1370 }
1371
1372 /*
1373  * Check whether we're fsgid/egid or in the supplemental group..
1374  */
1375 int in_group_p(gid_t grp)
1376 {
1377         int retval = 1;
1378         if (grp != current->fsgid) {
1379                 get_group_info(current->group_info);
1380                 retval = groups_search(current->group_info, grp);
1381                 put_group_info(current->group_info);
1382         }
1383         return retval;
1384 }
1385
1386 EXPORT_SYMBOL(in_group_p);
1387
1388 int in_egroup_p(gid_t grp)
1389 {
1390         int retval = 1;
1391         if (grp != current->egid) {
1392                 get_group_info(current->group_info);
1393                 retval = groups_search(current->group_info, grp);
1394                 put_group_info(current->group_info);
1395         }
1396         return retval;
1397 }
1398
1399 EXPORT_SYMBOL(in_egroup_p);
1400
1401 DECLARE_RWSEM(uts_sem);
1402
1403 EXPORT_SYMBOL(uts_sem);
1404
1405 asmlinkage long sys_newuname(struct new_utsname __user * name)
1406 {
1407         int errno = 0;
1408
1409         down_read(&uts_sem);
1410         if (copy_to_user(name,&system_utsname,sizeof *name))
1411                 errno = -EFAULT;
1412         up_read(&uts_sem);
1413         return errno;
1414 }
1415
1416 asmlinkage long sys_sethostname(char __user *name, int len)
1417 {
1418         int errno;
1419         char tmp[__NEW_UTS_LEN];
1420
1421         if (!capable(CAP_SYS_ADMIN))
1422                 return -EPERM;
1423         if (len < 0 || len > __NEW_UTS_LEN)
1424                 return -EINVAL;
1425         down_write(&uts_sem);
1426         errno = -EFAULT;
1427         if (!copy_from_user(tmp, name, len)) {
1428                 memcpy(system_utsname.nodename, tmp, len);
1429                 system_utsname.nodename[len] = 0;
1430                 errno = 0;
1431         }
1432         up_write(&uts_sem);
1433         return errno;
1434 }
1435
1436 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1437
1438 asmlinkage long sys_gethostname(char __user *name, int len)
1439 {
1440         int i, errno;
1441
1442         if (len < 0)
1443                 return -EINVAL;
1444         down_read(&uts_sem);
1445         i = 1 + strlen(system_utsname.nodename);
1446         if (i > len)
1447                 i = len;
1448         errno = 0;
1449         if (copy_to_user(name, system_utsname.nodename, i))
1450                 errno = -EFAULT;
1451         up_read(&uts_sem);
1452         return errno;
1453 }
1454
1455 #endif
1456
1457 /*
1458  * Only setdomainname; getdomainname can be implemented by calling
1459  * uname()
1460  */
1461 asmlinkage long sys_setdomainname(char __user *name, int len)
1462 {
1463         int errno;
1464         char tmp[__NEW_UTS_LEN];
1465
1466         if (!capable(CAP_SYS_ADMIN))
1467                 return -EPERM;
1468         if (len < 0 || len > __NEW_UTS_LEN)
1469                 return -EINVAL;
1470
1471         down_write(&uts_sem);
1472         errno = -EFAULT;
1473         if (!copy_from_user(tmp, name, len)) {
1474                 memcpy(system_utsname.domainname, tmp, len);
1475                 system_utsname.domainname[len] = 0;
1476                 errno = 0;
1477         }
1478         up_write(&uts_sem);
1479         return errno;
1480 }
1481
1482 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1483 {
1484         if (resource >= RLIM_NLIMITS)
1485                 return -EINVAL;
1486         else {
1487                 struct rlimit value;
1488                 task_lock(current->group_leader);
1489                 value = current->signal->rlim[resource];
1490                 task_unlock(current->group_leader);
1491                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1492         }
1493 }
1494
1495 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1496
1497 /*
1498  *      Back compatibility for getrlimit. Needed for some apps.
1499  */
1500
1501 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1502 {
1503         struct rlimit x;
1504         if (resource >= RLIM_NLIMITS)
1505                 return -EINVAL;
1506
1507         task_lock(current->group_leader);
1508         x = current->signal->rlim[resource];
1509         task_unlock(current->group_leader);
1510         if(x.rlim_cur > 0x7FFFFFFF)
1511                 x.rlim_cur = 0x7FFFFFFF;
1512         if(x.rlim_max > 0x7FFFFFFF)
1513                 x.rlim_max = 0x7FFFFFFF;
1514         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1515 }
1516
1517 #endif
1518
1519 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1520 {
1521         struct rlimit new_rlim, *old_rlim;
1522         int retval;
1523
1524         if (resource >= RLIM_NLIMITS)
1525                 return -EINVAL;
1526         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1527                 return -EFAULT;
1528        if (new_rlim.rlim_cur > new_rlim.rlim_max)
1529                return -EINVAL;
1530         old_rlim = current->signal->rlim + resource;
1531         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1532             !capable(CAP_SYS_RESOURCE))
1533                 return -EPERM;
1534         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1535                         return -EPERM;
1536
1537         retval = security_task_setrlimit(resource, &new_rlim);
1538         if (retval)
1539                 return retval;
1540
1541         task_lock(current->group_leader);
1542         *old_rlim = new_rlim;
1543         task_unlock(current->group_leader);
1544
1545         if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1546             (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1547              new_rlim.rlim_cur <= cputime_to_secs(
1548                      current->signal->it_prof_expires))) {
1549                 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1550                 read_lock(&tasklist_lock);
1551                 spin_lock_irq(&current->sighand->siglock);
1552                 set_process_cpu_timer(current, CPUCLOCK_PROF,
1553                                       &cputime, NULL);
1554                 spin_unlock_irq(&current->sighand->siglock);
1555                 read_unlock(&tasklist_lock);
1556         }
1557
1558         return 0;
1559 }
1560
1561 /*
1562  * It would make sense to put struct rusage in the task_struct,
1563  * except that would make the task_struct be *really big*.  After
1564  * task_struct gets moved into malloc'ed memory, it would
1565  * make sense to do this.  It will make moving the rest of the information
1566  * a lot simpler!  (Which we're not doing right now because we're not
1567  * measuring them yet).
1568  *
1569  * This expects to be called with tasklist_lock read-locked or better,
1570  * and the siglock not locked.  It may momentarily take the siglock.
1571  *
1572  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1573  * races with threads incrementing their own counters.  But since word
1574  * reads are atomic, we either get new values or old values and we don't
1575  * care which for the sums.  We always take the siglock to protect reading
1576  * the c* fields from p->signal from races with exit.c updating those
1577  * fields when reaping, so a sample either gets all the additions of a
1578  * given child after it's reaped, or none so this sample is before reaping.
1579  */
1580
1581 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1582 {
1583         struct task_struct *t;
1584         unsigned long flags;
1585         cputime_t utime, stime;
1586
1587         memset((char *) r, 0, sizeof *r);
1588
1589         if (unlikely(!p->signal))
1590                 return;
1591
1592         switch (who) {
1593                 case RUSAGE_CHILDREN:
1594                         spin_lock_irqsave(&p->sighand->siglock, flags);
1595                         utime = p->signal->cutime;
1596                         stime = p->signal->cstime;
1597                         r->ru_nvcsw = p->signal->cnvcsw;
1598                         r->ru_nivcsw = p->signal->cnivcsw;
1599                         r->ru_minflt = p->signal->cmin_flt;
1600                         r->ru_majflt = p->signal->cmaj_flt;
1601                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1602                         cputime_to_timeval(utime, &r->ru_utime);
1603                         cputime_to_timeval(stime, &r->ru_stime);
1604                         break;
1605                 case RUSAGE_SELF:
1606                         spin_lock_irqsave(&p->sighand->siglock, flags);
1607                         utime = stime = cputime_zero;
1608                         goto sum_group;
1609                 case RUSAGE_BOTH:
1610                         spin_lock_irqsave(&p->sighand->siglock, flags);
1611                         utime = p->signal->cutime;
1612                         stime = p->signal->cstime;
1613                         r->ru_nvcsw = p->signal->cnvcsw;
1614                         r->ru_nivcsw = p->signal->cnivcsw;
1615                         r->ru_minflt = p->signal->cmin_flt;
1616                         r->ru_majflt = p->signal->cmaj_flt;
1617                 sum_group:
1618                         utime = cputime_add(utime, p->signal->utime);
1619                         stime = cputime_add(stime, p->signal->stime);
1620                         r->ru_nvcsw += p->signal->nvcsw;
1621                         r->ru_nivcsw += p->signal->nivcsw;
1622                         r->ru_minflt += p->signal->min_flt;
1623                         r->ru_majflt += p->signal->maj_flt;
1624                         t = p;
1625                         do {
1626                                 utime = cputime_add(utime, t->utime);
1627                                 stime = cputime_add(stime, t->stime);
1628                                 r->ru_nvcsw += t->nvcsw;
1629                                 r->ru_nivcsw += t->nivcsw;
1630                                 r->ru_minflt += t->min_flt;
1631                                 r->ru_majflt += t->maj_flt;
1632                                 t = next_thread(t);
1633                         } while (t != p);
1634                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1635                         cputime_to_timeval(utime, &r->ru_utime);
1636                         cputime_to_timeval(stime, &r->ru_stime);
1637                         break;
1638                 default:
1639                         BUG();
1640         }
1641 }
1642
1643 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1644 {
1645         struct rusage r;
1646         read_lock(&tasklist_lock);
1647         k_getrusage(p, who, &r);
1648         read_unlock(&tasklist_lock);
1649         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1650 }
1651
1652 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1653 {
1654         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1655                 return -EINVAL;
1656         return getrusage(current, who, ru);
1657 }
1658
1659 asmlinkage long sys_umask(int mask)
1660 {
1661         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1662         return mask;
1663 }
1664
1665 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1666                           unsigned long arg4, unsigned long arg5)
1667 {
1668         long error;
1669         int sig;
1670
1671         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1672         if (error)
1673                 return error;
1674
1675         switch (option) {
1676                 case PR_SET_PDEATHSIG:
1677                         sig = arg2;
1678                         if (!valid_signal(sig)) {
1679                                 error = -EINVAL;
1680                                 break;
1681                         }
1682                         current->pdeath_signal = sig;
1683                         break;
1684                 case PR_GET_PDEATHSIG:
1685                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1686                         break;
1687                 case PR_GET_DUMPABLE:
1688                         if (current->mm->dumpable)
1689                                 error = 1;
1690                         break;
1691                 case PR_SET_DUMPABLE:
1692                         if (arg2 < 0 || arg2 > 2) {
1693                                 error = -EINVAL;
1694                                 break;
1695                         }
1696                         current->mm->dumpable = arg2;
1697                         break;
1698
1699                 case PR_SET_UNALIGN:
1700                         error = SET_UNALIGN_CTL(current, arg2);
1701                         break;
1702                 case PR_GET_UNALIGN:
1703                         error = GET_UNALIGN_CTL(current, arg2);
1704                         break;
1705                 case PR_SET_FPEMU:
1706                         error = SET_FPEMU_CTL(current, arg2);
1707                         break;
1708                 case PR_GET_FPEMU:
1709                         error = GET_FPEMU_CTL(current, arg2);
1710                         break;
1711                 case PR_SET_FPEXC:
1712                         error = SET_FPEXC_CTL(current, arg2);
1713                         break;
1714                 case PR_GET_FPEXC:
1715                         error = GET_FPEXC_CTL(current, arg2);
1716                         break;
1717                 case PR_GET_TIMING:
1718                         error = PR_TIMING_STATISTICAL;
1719                         break;
1720                 case PR_SET_TIMING:
1721                         if (arg2 == PR_TIMING_STATISTICAL)
1722                                 error = 0;
1723                         else
1724                                 error = -EINVAL;
1725                         break;
1726
1727                 case PR_GET_KEEPCAPS:
1728                         if (current->keep_capabilities)
1729                                 error = 1;
1730                         break;
1731                 case PR_SET_KEEPCAPS:
1732                         if (arg2 != 0 && arg2 != 1) {
1733                                 error = -EINVAL;
1734                                 break;
1735                         }
1736                         current->keep_capabilities = arg2;
1737                         break;
1738                 case PR_SET_NAME: {
1739                         struct task_struct *me = current;
1740                         unsigned char ncomm[sizeof(me->comm)];
1741
1742                         ncomm[sizeof(me->comm)-1] = 0;
1743                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1744                                                 sizeof(me->comm)-1) < 0)
1745                                 return -EFAULT;
1746                         set_task_comm(me, ncomm);
1747                         return 0;
1748                 }
1749                 case PR_GET_NAME: {
1750                         struct task_struct *me = current;
1751                         unsigned char tcomm[sizeof(me->comm)];
1752
1753                         get_task_comm(tcomm, me);
1754                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1755                                 return -EFAULT;
1756                         return 0;
1757                 }
1758                 default:
1759                         error = -EINVAL;
1760                         break;
1761         }
1762         return error;
1763 }