kernel/sys.c

   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/kernel.h>
  20 #include <linux/kexec.h>
  21 #include <linux/workqueue.h>
  22 #include <linux/device.h>
  23 #include <linux/key.h>
  24 #include <linux/times.h>
  25 #include <linux/posix-timers.h>
  26 #include <linux/security.h>
  27 #include <linux/dcookies.h>
  28 #include <linux/suspend.h>
  29 #include <linux/tty.h>
  30 #include <linux/signal.h>
  31 #include <linux/cn_proc.h>
  32
  33 #include <linux/compat.h>
  34 #include <linux/syscalls.h>
  35 #include <linux/kprobes.h>
  36
  37 #include <asm/uaccess.h>
  38 #include <asm/io.h>
  39 #include <asm/unistd.h>
  40
  41 #ifndef SET_UNALIGN_CTL
  42 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  43 #endif
  44 #ifndef GET_UNALIGN_CTL
  45 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  46 #endif
  47 #ifndef SET_FPEMU_CTL
  48 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  49 #endif
  50 #ifndef GET_FPEMU_CTL
  51 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  52 #endif
  53 #ifndef SET_FPEXC_CTL
  54 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  55 #endif
  56 #ifndef GET_FPEXC_CTL
  57 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  58 #endif
  59
  60 /*
  61  * this is where the system-wide overflow UID and GID are defined, for
  62  * architectures that now have 32-bit UID/GID but didn't in the past
  63  */
  64
  65 int overflowuid = DEFAULT_OVERFLOWUID;
  66 int overflowgid = DEFAULT_OVERFLOWGID;
  67
  68 #ifdef CONFIG_UID16
  69 EXPORT_SYMBOL(overflowuid);
  70 EXPORT_SYMBOL(overflowgid);
  71 #endif
  72
  73 /*
  74  * the same as above, but for filesystems which can only store a 16-bit
  75  * UID and GID. as such, this is needed on all architectures
  76  */
  77
  78 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  79 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
  80
  81 EXPORT_SYMBOL(fs_overflowuid);
  82 EXPORT_SYMBOL(fs_overflowgid);
  83
  84 /*
  85  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
  86  */
  87
  88 int C_A_D = 1;
  89 int cad_pid = 1;
  90
  91 /*
  92  *      Notifier list for kernel code which wants to be called
  93  *      at shutdown. This is used to stop any idling DMA operations
  94  *      and the like.
  95  */
  96
  97 static struct notifier_block *reboot_notifier_list;
  98 static DEFINE_RWLOCK(notifier_lock);
  99
 100 /**
 101  *      notifier_chain_register - Add notifier to a notifier chain
 102  *      @list: Pointer to root list pointer
 103  *      @n: New entry in notifier chain
 104  *
 105  *      Adds a notifier to a notifier chain.
 106  *
 107  *      Currently always returns zero.
 108  */
 109
 110 int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
 111 {
 112         write_lock(&notifier_lock);
 113         while(*list)
 114         {
 115                 if(n->priority > (*list)->priority)
 116                         break;
 117                 list= &((*list)->next);
 118         }
 119         n->next = *list;
 120         *list=n;
 121         write_unlock(&notifier_lock);
 122         return 0;
 123 }
 124
 125 EXPORT_SYMBOL(notifier_chain_register);
 126
 127 /**
 128  *      notifier_chain_unregister - Remove notifier from a notifier chain
 129  *      @nl: Pointer to root list pointer
 130  *      @n: New entry in notifier chain
 131  *
 132  *      Removes a notifier from a notifier chain.
 133  *
 134  *      Returns zero on success, or %-ENOENT on failure.
 135  */
 136
 137 int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
 138 {
 139         write_lock(&notifier_lock);
 140         while((*nl)!=NULL)
 141         {
 142                 if((*nl)==n)
 143                 {
 144                         *nl=n->next;
 145                         write_unlock(&notifier_lock);
 146                         return 0;
 147                 }
 148                 nl=&((*nl)->next);
 149         }
 150         write_unlock(&notifier_lock);
 151         return -ENOENT;
 152 }
 153
 154 EXPORT_SYMBOL(notifier_chain_unregister);
 155
 156 /**
 157  *      notifier_call_chain - Call functions in a notifier chain
 158  *      @n: Pointer to root pointer of notifier chain
 159  *      @val: Value passed unmodified to notifier function
 160  *      @v: Pointer passed unmodified to notifier function
 161  *
 162  *      Calls each function in a notifier chain in turn.
 163  *
 164  *      If the return value of the notifier can be and'd
 165  *      with %NOTIFY_STOP_MASK, then notifier_call_chain
 166  *      will return immediately, with the return value of
 167  *      the notifier function which halted execution.
 168  *      Otherwise, the return value is the return value
 169  *      of the last notifier function called.
 170  */
 171
 172 int __kprobes notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
 173 {
 174         int ret=NOTIFY_DONE;
 175         struct notifier_block *nb = *n;
 176
 177         while(nb)
 178         {
 179                 ret=nb->notifier_call(nb,val,v);
 180                 if(ret&NOTIFY_STOP_MASK)
 181                 {
 182                         return ret;
 183                 }
 184                 nb=nb->next;
 185         }
 186         return ret;
 187 }
 188
 189 EXPORT_SYMBOL(notifier_call_chain);
 190
 191 /**
 192  *      register_reboot_notifier - Register function to be called at reboot time
 193  *      @nb: Info about notifier function to be called
 194  *
 195  *      Registers a function with the list of functions
 196  *      to be called at reboot time.
 197  *
 198  *      Currently always returns zero, as notifier_chain_register
 199  *      always returns zero.
 200  */
 201
 202 int register_reboot_notifier(struct notifier_block * nb)
 203 {
 204         return notifier_chain_register(&reboot_notifier_list, nb);
 205 }
 206
 207 EXPORT_SYMBOL(register_reboot_notifier);
 208
 209 /**
 210  *      unregister_reboot_notifier - Unregister previously registered reboot notifier
 211  *      @nb: Hook to be unregistered
 212  *
 213  *      Unregisters a previously registered reboot
 214  *      notifier function.
 215  *
 216  *      Returns zero on success, or %-ENOENT on failure.
 217  */
 218
 219 int unregister_reboot_notifier(struct notifier_block * nb)
 220 {
 221         return notifier_chain_unregister(&reboot_notifier_list, nb);
 222 }
 223
 224 EXPORT_SYMBOL(unregister_reboot_notifier);
 225
 226 #ifndef CONFIG_SECURITY
 227 int capable(int cap)
 228 {
 229         if (cap_raised(current->cap_effective, cap)) {
 230                current->flags |= PF_SUPERPRIV;
 231                return 1;
 232         }
 233         return 0;
 234 }
 235 EXPORT_SYMBOL(capable);
 236 #endif
 237
 238 static int set_one_prio(struct task_struct *p, int niceval, int error)
 239 {
 240         int no_nice;
 241
 242         if (p->uid != current->euid &&
 243                 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
 244                 error = -EPERM;
 245                 goto out;
 246         }
 247         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 248                 error = -EACCES;
 249                 goto out;
 250         }
 251         no_nice = security_task_setnice(p, niceval);
 252         if (no_nice) {
 253                 error = no_nice;
 254                 goto out;
 255         }
 256         if (error == -ESRCH)
 257                 error = 0;
 258         set_user_nice(p, niceval);
 259 out:
 260         return error;
 261 }
 262
 263 asmlinkage long sys_setpriority(int which, int who, int niceval)
 264 {
 265         struct task_struct *g, *p;
 266         struct user_struct *user;
 267         int error = -EINVAL;
 268
 269         if (which > 2 || which < 0)
 270                 goto out;
 271
 272         /* normalize: avoid signed division (rounding problems) */
 273         error = -ESRCH;
 274         if (niceval < -20)
 275                 niceval = -20;
 276         if (niceval > 19)
 277                 niceval = 19;
 278
 279         read_lock(&tasklist_lock);
 280         switch (which) {
 281                 case PRIO_PROCESS:
 282                         if (!who)
 283                                 who = current->pid;
 284                         p = find_task_by_pid(who);
 285                         if (p)
 286                                 error = set_one_prio(p, niceval, error);
 287                         break;
 288                 case PRIO_PGRP:
 289                         if (!who)
 290                                 who = process_group(current);
 291                         do_each_task_pid(who, PIDTYPE_PGID, p) {
 292                                 error = set_one_prio(p, niceval, error);
 293                         } while_each_task_pid(who, PIDTYPE_PGID, p);
 294                         break;
 295                 case PRIO_USER:
 296                         user = current->user;
 297                         if (!who)
 298                                 who = current->uid;
 299                         else
 300                                 if ((who != current->uid) && !(user = find_user(who)))
 301                                         goto out_unlock;        /* No processes for this user */
 302
 303                         do_each_thread(g, p)
 304                                 if (p->uid == who)
 305                                         error = set_one_prio(p, niceval, error);
 306                         while_each_thread(g, p);
 307                         if (who != current->uid)
 308                                 free_uid(user);         /* For find_user() */
 309                         break;
 310         }
 311 out_unlock:
 312         read_unlock(&tasklist_lock);
 313 out:
 314         return error;
 315 }
 316
 317 /*
 318  * Ugh. To avoid negative return values, "getpriority()" will
 319  * not return the normal nice-value, but a negated value that
 320  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 321  * to stay compatible.
 322  */
 323 asmlinkage long sys_getpriority(int which, int who)
 324 {
 325         struct task_struct *g, *p;
 326         struct user_struct *user;
 327         long niceval, retval = -ESRCH;
 328
 329         if (which > 2 || which < 0)
 330                 return -EINVAL;
 331
 332         read_lock(&tasklist_lock);
 333         switch (which) {
 334                 case PRIO_PROCESS:
 335                         if (!who)
 336                                 who = current->pid;
 337                         p = find_task_by_pid(who);
 338                         if (p) {
 339                                 niceval = 20 - task_nice(p);
 340                                 if (niceval > retval)
 341                                         retval = niceval;
 342                         }
 343                         break;
 344                 case PRIO_PGRP:
 345                         if (!who)
 346                                 who = process_group(current);
 347                         do_each_task_pid(who, PIDTYPE_PGID, p) {
 348                                 niceval = 20 - task_nice(p);
 349                                 if (niceval > retval)
 350                                         retval = niceval;
 351                         } while_each_task_pid(who, PIDTYPE_PGID, p);
 352                         break;
 353                 case PRIO_USER:
 354                         user = current->user;
 355                         if (!who)
 356                                 who = current->uid;
 357                         else
 358                                 if ((who != current->uid) && !(user = find_user(who)))
 359                                         goto out_unlock;        /* No processes for this user */
 360
 361                         do_each_thread(g, p)
 362                                 if (p->uid == who) {
 363                                         niceval = 20 - task_nice(p);
 364                                         if (niceval > retval)
 365                                                 retval = niceval;
 366                                 }
 367                         while_each_thread(g, p);
 368                         if (who != current->uid)
 369                                 free_uid(user);         /* for find_user() */
 370                         break;
 371         }
 372 out_unlock:
 373         read_unlock(&tasklist_lock);
 374
 375         return retval;
 376 }
 377
 378 /**
 379  *      emergency_restart - reboot the system
 380  *
 381  *      Without shutting down any hardware or taking any locks
 382  *      reboot the system.  This is called when we know we are in
 383  *      trouble so this is our best effort to reboot.  This is
 384  *      safe to call in interrupt context.
 385  */
 386 void emergency_restart(void)
 387 {
 388         machine_emergency_restart();
 389 }
 390 EXPORT_SYMBOL_GPL(emergency_restart);
 391
 392 void kernel_restart_prepare(char *cmd)
 393 {
 394         notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 395         system_state = SYSTEM_RESTART;
 396         device_shutdown();
 397 }
 398
 399 /**
 400  *      kernel_restart - reboot the system
 401  *      @cmd: pointer to buffer containing command to execute for restart
 402  *              or %NULL
 403  *
 404  *      Shutdown everything and perform a clean reboot.
 405  *      This is not safe to call in interrupt context.
 406  */
 407 void kernel_restart(char *cmd)
 408 {
 409         kernel_restart_prepare(cmd);
 410         if (!cmd) {
 411                 printk(KERN_EMERG "Restarting system.\n");
 412         } else {
 413                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 414         }
 415         printk(".\n");
 416         machine_restart(cmd);
 417 }
 418 EXPORT_SYMBOL_GPL(kernel_restart);
 419
 420 /**
 421  *      kernel_kexec - reboot the system
 422  *
 423  *      Move into place and start executing a preloaded standalone
 424  *      executable.  If nothing was preloaded return an error.
 425  */
 426 void kernel_kexec(void)
 427 {
 428 #ifdef CONFIG_KEXEC
 429         struct kimage *image;
 430         image = xchg(&kexec_image, 0);
 431         if (!image) {
 432                 return;
 433         }
 434         kernel_restart_prepare(NULL);
 435         printk(KERN_EMERG "Starting new kernel\n");
 436         machine_shutdown();
 437         machine_kexec(image);
 438 #endif
 439 }
 440 EXPORT_SYMBOL_GPL(kernel_kexec);
 441
 442 /**
 443  *      kernel_halt - halt the system
 444  *
 445  *      Shutdown everything and perform a clean system halt.
 446  */
 447 void kernel_halt_prepare(void)
 448 {
 449         notifier_call_chain(&reboot_notifier_list, SYS_HALT, NULL);
 450         system_state = SYSTEM_HALT;
 451         device_shutdown();
 452 }
 453 void kernel_halt(void)
 454 {
 455         kernel_halt_prepare();
 456         printk(KERN_EMERG "System halted.\n");
 457         machine_halt();
 458 }
 459 EXPORT_SYMBOL_GPL(kernel_halt);
 460
 461 /**
 462  *      kernel_power_off - power_off the system
 463  *
 464  *      Shutdown everything and perform a clean system power_off.
 465  */
 466 void kernel_power_off_prepare(void)
 467 {
 468         notifier_call_chain(&reboot_notifier_list, SYS_POWER_OFF, NULL);
 469         system_state = SYSTEM_POWER_OFF;
 470         device_shutdown();
 471 }
 472 void kernel_power_off(void)
 473 {
 474         kernel_power_off_prepare();
 475         printk(KERN_EMERG "Power down.\n");
 476         machine_power_off();
 477 }
 478 EXPORT_SYMBOL_GPL(kernel_power_off);
 479
 480 /*
 481  * Reboot system call: for obvious reasons only root may call it,
 482  * and even root needs to set up some magic numbers in the registers
 483  * so that some mistake won't make this reboot the whole machine.
 484  * You can also set the meaning of the ctrl-alt-del-key here.
 485  *
 486  * reboot doesn't sync: do that yourself before calling this.
 487  */
 488 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
 489 {
 490         char buffer[256];
 491
 492         /* We only trust the superuser with rebooting the system. */
 493         if (!capable(CAP_SYS_BOOT))
 494                 return -EPERM;
 495
 496         /* For safety, we require "magic" arguments. */
 497         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 498             (magic2 != LINUX_REBOOT_MAGIC2 &&
 499                         magic2 != LINUX_REBOOT_MAGIC2A &&
 500                         magic2 != LINUX_REBOOT_MAGIC2B &&
 501                         magic2 != LINUX_REBOOT_MAGIC2C))
 502                 return -EINVAL;
 503
 504         /* Instead of trying to make the power_off code look like
 505          * halt when pm_power_off is not set do it the easy way.
 506          */
 507         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 508                 cmd = LINUX_REBOOT_CMD_HALT;
 509
 510         lock_kernel();
 511         switch (cmd) {
 512         case LINUX_REBOOT_CMD_RESTART:
 513                 kernel_restart(NULL);
 514                 break;
 515
 516         case LINUX_REBOOT_CMD_CAD_ON:
 517                 C_A_D = 1;
 518                 break;
 519
 520         case LINUX_REBOOT_CMD_CAD_OFF:
 521                 C_A_D = 0;
 522                 break;
 523
 524         case LINUX_REBOOT_CMD_HALT:
 525                 kernel_halt();
 526                 unlock_kernel();
 527                 do_exit(0);
 528                 break;
 529
 530         case LINUX_REBOOT_CMD_POWER_OFF:
 531                 kernel_power_off();
 532                 unlock_kernel();
 533                 do_exit(0);
 534                 break;
 535
 536         case LINUX_REBOOT_CMD_RESTART2:
 537                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 538                         unlock_kernel();
 539                         return -EFAULT;
 540                 }
 541                 buffer[sizeof(buffer) - 1] = '\0';
 542
 543                 kernel_restart(buffer);
 544                 break;
 545
 546         case LINUX_REBOOT_CMD_KEXEC:
 547                 kernel_kexec();
 548                 unlock_kernel();
 549                 return -EINVAL;
 550
 551 #ifdef CONFIG_SOFTWARE_SUSPEND
 552         case LINUX_REBOOT_CMD_SW_SUSPEND:
 553                 {
 554                         int ret = software_suspend();
 555                         unlock_kernel();
 556                         return ret;
 557                 }
 558 #endif
 559
 560         default:
 561                 unlock_kernel();
 562                 return -EINVAL;
 563         }
 564         unlock_kernel();
 565         return 0;
 566 }
 567
 568 static void deferred_cad(void *dummy)
 569 {
 570         kernel_restart(NULL);
 571 }
 572
 573 /*
 574  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 575  * As it's called within an interrupt, it may NOT sync: the only choice
 576  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 577  */
 578 void ctrl_alt_del(void)
 579 {
 580         static DECLARE_WORK(cad_work, deferred_cad, NULL);
 581
 582         if (C_A_D)
 583                 schedule_work(&cad_work);
 584         else
 585                 kill_proc(cad_pid, SIGINT, 1);
 586 }
 587
 588
 589 /*
 590  * Unprivileged users may change the real gid to the effective gid
 591  * or vice versa.  (BSD-style)
 592  *
 593  * If you set the real gid at all, or set the effective gid to a value not
 594  * equal to the real gid, then the saved gid is set to the new effective gid.
 595  *
 596  * This makes it possible for a setgid program to completely drop its
 597  * privileges, which is often a useful assertion to make when you are doing
 598  * a security audit over a program.
 599  *
 600  * The general idea is that a program which uses just setregid() will be
 601  * 100% compatible with BSD.  A program which uses just setgid() will be
 602  * 100% compatible with POSIX with saved IDs.
 603  *
 604  * SMP: There are not races, the GIDs are checked only by filesystem
 605  *      operations (as far as semantic preservation is concerned).
 606  */
 607 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
 608 {
 609         int old_rgid = current->gid;
 610         int old_egid = current->egid;
 611         int new_rgid = old_rgid;
 612         int new_egid = old_egid;
 613         int retval;
 614
 615         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 616         if (retval)
 617                 return retval;
 618
 619         if (rgid != (gid_t) -1) {
 620                 if ((old_rgid == rgid) ||
 621                     (current->egid==rgid) ||
 622                     capable(CAP_SETGID))
 623                         new_rgid = rgid;
 624                 else
 625                         return -EPERM;
 626         }
 627         if (egid != (gid_t) -1) {
 628                 if ((old_rgid == egid) ||
 629                     (current->egid == egid) ||
 630                     (current->sgid == egid) ||
 631                     capable(CAP_SETGID))
 632                         new_egid = egid;
 633                 else {
 634                         return -EPERM;
 635                 }
 636         }
 637         if (new_egid != old_egid)
 638         {
 639                 current->mm->dumpable = suid_dumpable;
 640                 smp_wmb();
 641         }
 642         if (rgid != (gid_t) -1 ||
 643             (egid != (gid_t) -1 && egid != old_rgid))
 644                 current->sgid = new_egid;
 645         current->fsgid = new_egid;
 646         current->egid = new_egid;
 647         current->gid = new_rgid;
 648         key_fsgid_changed(current);
 649         proc_id_connector(current, PROC_EVENT_GID);
 650         return 0;
 651 }
 652
 653 /*
 654  * setgid() is implemented like SysV w/ SAVED_IDS
 655  *
 656  * SMP: Same implicit races as above.
 657  */
 658 asmlinkage long sys_setgid(gid_t gid)
 659 {
 660         int old_egid = current->egid;
 661         int retval;
 662
 663         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 664         if (retval)
 665                 return retval;
 666
 667         if (capable(CAP_SETGID))
 668         {
 669                 if(old_egid != gid)
 670                 {
 671                         current->mm->dumpable = suid_dumpable;
 672                         smp_wmb();
 673                 }
 674                 current->gid = current->egid = current->sgid = current->fsgid = gid;
 675         }
 676         else if ((gid == current->gid) || (gid == current->sgid))
 677         {
 678                 if(old_egid != gid)
 679                 {
 680                         current->mm->dumpable = suid_dumpable;
 681                         smp_wmb();
 682                 }
 683                 current->egid = current->fsgid = gid;
 684         }
 685         else
 686                 return -EPERM;
 687
 688         key_fsgid_changed(current);
 689         proc_id_connector(current, PROC_EVENT_GID);
 690         return 0;
 691 }
 692
 693 static int set_user(uid_t new_ruid, int dumpclear)
 694 {
 695         struct user_struct *new_user;
 696
 697         new_user = alloc_uid(new_ruid);
 698         if (!new_user)
 699                 return -EAGAIN;
 700
 701         if (atomic_read(&new_user->processes) >=
 702                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 703                         new_user != &root_user) {
 704                 free_uid(new_user);
 705                 return -EAGAIN;
 706         }
 707
 708         switch_uid(new_user);
 709
 710         if(dumpclear)
 711         {
 712                 current->mm->dumpable = suid_dumpable;
 713                 smp_wmb();
 714         }
 715         current->uid = new_ruid;
 716         return 0;
 717 }
 718
 719 /*
 720  * Unprivileged users may change the real uid to the effective uid
 721  * or vice versa.  (BSD-style)
 722  *
 723  * If you set the real uid at all, or set the effective uid to a value not
 724  * equal to the real uid, then the saved uid is set to the new effective uid.
 725  *
 726  * This makes it possible for a setuid program to completely drop its
 727  * privileges, which is often a useful assertion to make when you are doing
 728  * a security audit over a program.
 729  *
 730  * The general idea is that a program which uses just setreuid() will be
 731  * 100% compatible with BSD.  A program which uses just setuid() will be
 732  * 100% compatible with POSIX with saved IDs.
 733  */
 734 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 735 {
 736         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
 737         int retval;
 738
 739         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 740         if (retval)
 741                 return retval;
 742
 743         new_ruid = old_ruid = current->uid;
 744         new_euid = old_euid = current->euid;
 745         old_suid = current->suid;
 746
 747         if (ruid != (uid_t) -1) {
 748                 new_ruid = ruid;
 749                 if ((old_ruid != ruid) &&
 750                     (current->euid != ruid) &&
 751                     !capable(CAP_SETUID))
 752                         return -EPERM;
 753         }
 754
 755         if (euid != (uid_t) -1) {
 756                 new_euid = euid;
 757                 if ((old_ruid != euid) &&
 758                     (current->euid != euid) &&
 759                     (current->suid != euid) &&
 760                     !capable(CAP_SETUID))
 761                         return -EPERM;
 762         }
 763
 764         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
 765                 return -EAGAIN;
 766
 767         if (new_euid != old_euid)
 768         {
 769                 current->mm->dumpable = suid_dumpable;
 770                 smp_wmb();
 771         }
 772         current->fsuid = current->euid = new_euid;
 773         if (ruid != (uid_t) -1 ||
 774             (euid != (uid_t) -1 && euid != old_ruid))
 775                 current->suid = current->euid;
 776         current->fsuid = current->euid;
 777
 778         key_fsuid_changed(current);
 779         proc_id_connector(current, PROC_EVENT_UID);
 780
 781         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
 782 }
 783
 784
 785
 786 /*
 787  * setuid() is implemented like SysV with SAVED_IDS
 788  *
 789  * Note that SAVED_ID's is deficient in that a setuid root program
 790  * like sendmail, for example, cannot set its uid to be a normal
 791  * user and then switch back, because if you're root, setuid() sets
 792  * the saved uid too.  If you don't like this, blame the bright people
 793  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 794  * will allow a root program to temporarily drop privileges and be able to
 795  * regain them by swapping the real and effective uid.
 796  */
 797 asmlinkage long sys_setuid(uid_t uid)
 798 {
 799         int old_euid = current->euid;
 800         int old_ruid, old_suid, new_ruid, new_suid;
 801         int retval;
 802
 803         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 804         if (retval)
 805                 return retval;
 806
 807         old_ruid = new_ruid = current->uid;
 808         old_suid = current->suid;
 809         new_suid = old_suid;
 810
 811         if (capable(CAP_SETUID)) {
 812                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
 813                         return -EAGAIN;
 814                 new_suid = uid;
 815         } else if ((uid != current->uid) && (uid != new_suid))
 816                 return -EPERM;
 817
 818         if (old_euid != uid)
 819         {
 820                 current->mm->dumpable = suid_dumpable;
 821                 smp_wmb();
 822         }
 823         current->fsuid = current->euid = uid;
 824         current->suid = new_suid;
 825
 826         key_fsuid_changed(current);
 827         proc_id_connector(current, PROC_EVENT_UID);
 828
 829         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
 830 }
 831
 832
 833 /*
 834  * This function implements a generic ability to update ruid, euid,
 835  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 836  */
 837 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 838 {
 839         int old_ruid = current->uid;
 840         int old_euid = current->euid;
 841         int old_suid = current->suid;
 842         int retval;
 843
 844         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 845         if (retval)
 846                 return retval;
 847
 848         if (!capable(CAP_SETUID)) {
 849                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
 850                     (ruid != current->euid) && (ruid != current->suid))
 851                         return -EPERM;
 852                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
 853                     (euid != current->euid) && (euid != current->suid))
 854                         return -EPERM;
 855                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
 856                     (suid != current->euid) && (suid != current->suid))
 857                         return -EPERM;
 858         }
 859         if (ruid != (uid_t) -1) {
 860                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
 861                         return -EAGAIN;
 862         }
 863         if (euid != (uid_t) -1) {
 864                 if (euid != current->euid)
 865                 {
 866                         current->mm->dumpable = suid_dumpable;
 867                         smp_wmb();
 868                 }
 869                 current->euid = euid;
 870         }
 871         current->fsuid = current->euid;
 872         if (suid != (uid_t) -1)
 873                 current->suid = suid;
 874
 875         key_fsuid_changed(current);
 876         proc_id_connector(current, PROC_EVENT_UID);
 877
 878         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
 879 }
 880
 881 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
 882 {
 883         int retval;
 884
 885         if (!(retval = put_user(current->uid, ruid)) &&
 886             !(retval = put_user(current->euid, euid)))
 887                 retval = put_user(current->suid, suid);
 888
 889         return retval;
 890 }
 891
 892 /*
 893  * Same as above, but for rgid, egid, sgid.
 894  */
 895 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 896 {
 897         int retval;
 898
 899         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 900         if (retval)
 901                 return retval;
 902
 903         if (!capable(CAP_SETGID)) {
 904                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
 905                     (rgid != current->egid) && (rgid != current->sgid))
 906                         return -EPERM;
 907                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
 908                     (egid != current->egid) && (egid != current->sgid))
 909                         return -EPERM;
 910                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
 911                     (sgid != current->egid) && (sgid != current->sgid))
 912                         return -EPERM;
 913         }
 914         if (egid != (gid_t) -1) {
 915                 if (egid != current->egid)
 916                 {
 917                         current->mm->dumpable = suid_dumpable;
 918                         smp_wmb();
 919                 }
 920                 current->egid = egid;
 921         }
 922         current->fsgid = current->egid;
 923         if (rgid != (gid_t) -1)
 924                 current->gid = rgid;
 925         if (sgid != (gid_t) -1)
 926                 current->sgid = sgid;
 927
 928         key_fsgid_changed(current);
 929         proc_id_connector(current, PROC_EVENT_GID);
 930         return 0;
 931 }
 932
 933 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
 934 {
 935         int retval;
 936
 937         if (!(retval = put_user(current->gid, rgid)) &&
 938             !(retval = put_user(current->egid, egid)))
 939                 retval = put_user(current->sgid, sgid);
 940
 941         return retval;
 942 }
 943
 944
 945 /*
 946  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 947  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 948  * whatever uid it wants to). It normally shadows "euid", except when
 949  * explicitly set by setfsuid() or for access..
 950  */
 951 asmlinkage long sys_setfsuid(uid_t uid)
 952 {
 953         int old_fsuid;
 954
 955         old_fsuid = current->fsuid;
 956         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
 957                 return old_fsuid;
 958
 959         if (uid == current->uid || uid == current->euid ||
 960             uid == current->suid || uid == current->fsuid ||
 961             capable(CAP_SETUID))
 962         {
 963                 if (uid != old_fsuid)
 964                 {
 965                         current->mm->dumpable = suid_dumpable;
 966                         smp_wmb();
 967                 }
 968                 current->fsuid = uid;
 969         }
 970
 971         key_fsuid_changed(current);
 972         proc_id_connector(current, PROC_EVENT_UID);
 973
 974         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
 975
 976         return old_fsuid;
 977 }
 978
 979 /*
 980  * Samma på svenska..
 981  */
 982 asmlinkage long sys_setfsgid(gid_t gid)
 983 {
 984         int old_fsgid;
 985
 986         old_fsgid = current->fsgid;
 987         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 988                 return old_fsgid;
 989
 990         if (gid == current->gid || gid == current->egid ||
 991             gid == current->sgid || gid == current->fsgid ||
 992             capable(CAP_SETGID))
 993         {
 994                 if (gid != old_fsgid)
 995                 {
 996                         current->mm->dumpable = suid_dumpable;
 997                         smp_wmb();
 998                 }
 999                 current->fsgid = gid;
1000                 key_fsgid_changed(current);
1001                 proc_id_connector(current, PROC_EVENT_GID);
1002         }
1003         return old_fsgid;
1004 }
1005
1006 asmlinkage long sys_times(struct tms __user * tbuf)
1007 {
1008         /*
1009          *      In the SMP world we might just be unlucky and have one of
1010          *      the times increment as we use it. Since the value is an
1011          *      atomically safe type this is just fine. Conceptually its
1012          *      as if the syscall took an instant longer to occur.
1013          */
1014         if (tbuf) {
1015                 struct tms tmp;
1016                 cputime_t utime, stime, cutime, cstime;
1017
1018 #ifdef CONFIG_SMP
1019                 if (thread_group_empty(current)) {
1020                         /*
1021                          * Single thread case without the use of any locks.
1022                          *
1023                          * We may race with release_task if two threads are
1024                          * executing. However, release task first adds up the
1025                          * counters (__exit_signal) before  removing the task
1026                          * from the process tasklist (__unhash_process).
1027                          * __exit_signal also acquires and releases the
1028                          * siglock which results in the proper memory ordering
1029                          * so that the list modifications are always visible
1030                          * after the counters have been updated.
1031                          *
1032                          * If the counters have been updated by the second thread
1033                          * but the thread has not yet been removed from the list
1034                          * then the other branch will be executing which will
1035                          * block on tasklist_lock until the exit handling of the
1036                          * other task is finished.
1037                          *
1038                          * This also implies that the sighand->siglock cannot
1039                          * be held by another processor. So we can also
1040                          * skip acquiring that lock.
1041                          */
1042                         utime = cputime_add(current->signal->utime, current->utime);
1043                         stime = cputime_add(current->signal->utime, current->stime);
1044                         cutime = current->signal->cutime;
1045                         cstime = current->signal->cstime;
1046                 } else
1047 #endif
1048                 {
1049
1050                         /* Process with multiple threads */
1051                         struct task_struct *tsk = current;
1052                         struct task_struct *t;
1053
1054                         read_lock(&tasklist_lock);
1055                         utime = tsk->signal->utime;
1056                         stime = tsk->signal->stime;
1057                         t = tsk;
1058                         do {
1059                                 utime = cputime_add(utime, t->utime);
1060                                 stime = cputime_add(stime, t->stime);
1061                                 t = next_thread(t);
1062                         } while (t != tsk);
1063
1064                         /*
1065                          * While we have tasklist_lock read-locked, no dying thread
1066                          * can be updating current->signal->[us]time.  Instead,
1067                          * we got their counts included in the live thread loop.
1068                          * However, another thread can come in right now and
1069                          * do a wait call that updates current->signal->c[us]time.
1070                          * To make sure we always see that pair updated atomically,
1071                          * we take the siglock around fetching them.
1072                          */
1073                         spin_lock_irq(&tsk->sighand->siglock);
1074                         cutime = tsk->signal->cutime;
1075                         cstime = tsk->signal->cstime;
1076                         spin_unlock_irq(&tsk->sighand->siglock);
1077                         read_unlock(&tasklist_lock);
1078                 }
1079                 tmp.tms_utime = cputime_to_clock_t(utime);
1080                 tmp.tms_stime = cputime_to_clock_t(stime);
1081                 tmp.tms_cutime = cputime_to_clock_t(cutime);
1082                 tmp.tms_cstime = cputime_to_clock_t(cstime);
1083                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
1084                         return -EFAULT;
1085         }
1086         return (long) jiffies_64_to_clock_t(get_jiffies_64());
1087 }
1088
1089 /*
1090  * This needs some heavy checking ...
1091  * I just haven't the stomach for it. I also don't fully
1092  * understand sessions/pgrp etc. Let somebody who does explain it.
1093  *
1094  * OK, I think I have the protection semantics right.... this is really
1095  * only important on a multi-user system anyway, to make sure one user
1096  * can't send a signal to a process owned by another.  -TYT, 12/12/91
1097  *
1098  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
1099  * LBT 04.03.94
1100  */
1101
1102 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
1103 {
1104         struct task_struct *p;
1105         struct task_struct *group_leader = current->group_leader;
1106         int err = -EINVAL;
1107
1108         if (!pid)
1109                 pid = group_leader->pid;
1110         if (!pgid)
1111                 pgid = pid;
1112         if (pgid < 0)
1113                 return -EINVAL;
1114
1115         /* From this point forward we keep holding onto the tasklist lock
1116          * so that our parent does not change from under us. -DaveM
1117          */
1118         write_lock_irq(&tasklist_lock);
1119
1120         err = -ESRCH;
1121         p = find_task_by_pid(pid);
1122         if (!p)
1123                 goto out;
1124
1125         err = -EINVAL;
1126         if (!thread_group_leader(p))
1127                 goto out;
1128
1129         if (p->real_parent == group_leader) {
1130                 err = -EPERM;
1131                 if (p->signal->session != group_leader->signal->session)
1132                         goto out;
1133                 err = -EACCES;
1134                 if (p->did_exec)
1135                         goto out;
1136         } else {
1137                 err = -ESRCH;
1138                 if (p != group_leader)
1139                         goto out;
1140         }
1141
1142         err = -EPERM;
1143         if (p->signal->leader)
1144                 goto out;
1145
1146         if (pgid != pid) {
1147                 struct task_struct *p;
1148
1149                 do_each_task_pid(pgid, PIDTYPE_PGID, p) {
1150                         if (p->signal->session == group_leader->signal->session)
1151                                 goto ok_pgid;
1152                 } while_each_task_pid(pgid, PIDTYPE_PGID, p);
1153                 goto out;
1154         }
1155
1156 ok_pgid:
1157         err = security_task_setpgid(p, pgid);
1158         if (err)
1159                 goto out;
1160
1161         if (process_group(p) != pgid) {
1162                 detach_pid(p, PIDTYPE_PGID);
1163                 p->signal->pgrp = pgid;
1164                 attach_pid(p, PIDTYPE_PGID, pgid);
1165         }
1166
1167         err = 0;
1168 out:
1169         /* All paths lead to here, thus we are safe. -DaveM */
1170         write_unlock_irq(&tasklist_lock);
1171         return err;
1172 }
1173
1174 asmlinkage long sys_getpgid(pid_t pid)
1175 {
1176         if (!pid) {
1177                 return process_group(current);
1178         } else {
1179                 int retval;
1180                 struct task_struct *p;
1181
1182                 read_lock(&tasklist_lock);
1183                 p = find_task_by_pid(pid);
1184
1185                 retval = -ESRCH;
1186                 if (p) {
1187                         retval = security_task_getpgid(p);
1188                         if (!retval)
1189                                 retval = process_group(p);
1190                 }
1191                 read_unlock(&tasklist_lock);
1192                 return retval;
1193         }
1194 }
1195
1196 #ifdef __ARCH_WANT_SYS_GETPGRP
1197
1198 asmlinkage long sys_getpgrp(void)
1199 {
1200         /* SMP - assuming writes are word atomic this is fine */
1201         return process_group(current);
1202 }
1203
1204 #endif
1205
1206 asmlinkage long sys_getsid(pid_t pid)
1207 {
1208         if (!pid) {
1209                 return current->signal->session;
1210         } else {
1211                 int retval;
1212                 struct task_struct *p;
1213
1214                 read_lock(&tasklist_lock);
1215                 p = find_task_by_pid(pid);
1216
1217                 retval = -ESRCH;
1218                 if(p) {
1219                         retval = security_task_getsid(p);
1220                         if (!retval)
1221                                 retval = p->signal->session;
1222                 }
1223                 read_unlock(&tasklist_lock);
1224                 return retval;
1225         }
1226 }
1227
1228 asmlinkage long sys_setsid(void)
1229 {
1230         struct task_struct *group_leader = current->group_leader;
1231         struct pid *pid;
1232         int err = -EPERM;
1233
1234         down(&tty_sem);
1235         write_lock_irq(&tasklist_lock);
1236
1237         pid = find_pid(PIDTYPE_PGID, group_leader->pid);
1238         if (pid)
1239                 goto out;
1240
1241         group_leader->signal->leader = 1;
1242         __set_special_pids(group_leader->pid, group_leader->pid);
1243         group_leader->signal->tty = NULL;
1244         group_leader->signal->tty_old_pgrp = 0;
1245         err = process_group(group_leader);
1246 out:
1247         write_unlock_irq(&tasklist_lock);
1248         up(&tty_sem);
1249         return err;
1250 }
1251
1252 /*
1253  * Supplementary group IDs
1254  */
1255
1256 /* init to 2 - one for init_task, one to ensure it is never freed */
1257 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1258
1259 struct group_info *groups_alloc(int gidsetsize)
1260 {
1261         struct group_info *group_info;
1262         int nblocks;
1263         int i;
1264
1265         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1266         /* Make sure we always allocate at least one indirect block pointer */
1267         nblocks = nblocks ? : 1;
1268         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1269         if (!group_info)
1270                 return NULL;
1271         group_info->ngroups = gidsetsize;
1272         group_info->nblocks = nblocks;
1273         atomic_set(&group_info->usage, 1);
1274
1275         if (gidsetsize <= NGROUPS_SMALL) {
1276                 group_info->blocks[0] = group_info->small_block;
1277         } else {
1278                 for (i = 0; i < nblocks; i++) {
1279                         gid_t *b;
1280                         b = (void *)__get_free_page(GFP_USER);
1281                         if (!b)
1282                                 goto out_undo_partial_alloc;
1283                         group_info->blocks[i] = b;
1284                 }
1285         }
1286         return group_info;
1287
1288 out_undo_partial_alloc:
1289         while (--i >= 0) {
1290                 free_page((unsigned long)group_info->blocks[i]);
1291         }
1292         kfree(group_info);
1293         return NULL;
1294 }
1295
1296 EXPORT_SYMBOL(groups_alloc);
1297
1298 void groups_free(struct group_info *group_info)
1299 {
1300         if (group_info->blocks[0] != group_info->small_block) {
1301                 int i;
1302                 for (i = 0; i < group_info->nblocks; i++)
1303                         free_page((unsigned long)group_info->blocks[i]);
1304         }
1305         kfree(group_info);
1306 }
1307
1308 EXPORT_SYMBOL(groups_free);
1309
1310 /* export the group_info to a user-space array */
1311 static int groups_to_user(gid_t __user *grouplist,
1312     struct group_info *group_info)
1313 {
1314         int i;
1315         int count = group_info->ngroups;
1316
1317         for (i = 0; i < group_info->nblocks; i++) {
1318                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1319                 int off = i * NGROUPS_PER_BLOCK;
1320                 int len = cp_count * sizeof(*grouplist);
1321
1322                 if (copy_to_user(grouplist+off, group_info->blocks[i], len))
1323                         return -EFAULT;
1324
1325                 count -= cp_count;
1326         }
1327         return 0;
1328 }
1329
1330 /* fill a group_info from a user-space array - it must be allocated already */
1331 static int groups_from_user(struct group_info *group_info,
1332     gid_t __user *grouplist)
1333  {
1334         int i;
1335         int count = group_info->ngroups;
1336
1337         for (i = 0; i < group_info->nblocks; i++) {
1338                 int cp_count = min(NGROUPS_PER_BLOCK, count);
1339                 int off = i * NGROUPS_PER_BLOCK;
1340                 int len = cp_count * sizeof(*grouplist);
1341
1342                 if (copy_from_user(group_info->blocks[i], grouplist+off, len))
1343                         return -EFAULT;
1344
1345                 count -= cp_count;
1346         }
1347         return 0;
1348 }
1349
1350 /* a simple Shell sort */
1351 static void groups_sort(struct group_info *group_info)
1352 {
1353         int base, max, stride;
1354         int gidsetsize = group_info->ngroups;
1355
1356         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1357                 ; /* nothing */
1358         stride /= 3;
1359
1360         while (stride) {
1361                 max = gidsetsize - stride;
1362                 for (base = 0; base < max; base++) {
1363                         int left = base;
1364                         int right = left + stride;
1365                         gid_t tmp = GROUP_AT(group_info, right);
1366
1367                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1368                                 GROUP_AT(group_info, right) =
1369                                     GROUP_AT(group_info, left);
1370                                 right = left;
1371                                 left -= stride;
1372                         }
1373                         GROUP_AT(group_info, right) = tmp;
1374                 }
1375                 stride /= 3;
1376         }
1377 }
1378
1379 /* a simple bsearch */
1380 int groups_search(struct group_info *group_info, gid_t grp)
1381 {
1382         int left, right;
1383
1384         if (!group_info)
1385                 return 0;
1386
1387         left = 0;
1388         right = group_info->ngroups;
1389         while (left < right) {
1390                 int mid = (left+right)/2;
1391                 int cmp = grp - GROUP_AT(group_info, mid);
1392                 if (cmp > 0)
1393                         left = mid + 1;
1394                 else if (cmp < 0)
1395                         right = mid;
1396                 else
1397                         return 1;
1398         }
1399         return 0;
1400 }
1401
1402 /* validate and set current->group_info */
1403 int set_current_groups(struct group_info *group_info)
1404 {
1405         int retval;
1406         struct group_info *old_info;
1407
1408         retval = security_task_setgroups(group_info);
1409         if (retval)
1410                 return retval;
1411
1412         groups_sort(group_info);
1413         get_group_info(group_info);
1414
1415         task_lock(current);
1416         old_info = current->group_info;
1417         current->group_info = group_info;
1418         task_unlock(current);
1419
1420         put_group_info(old_info);
1421
1422         return 0;
1423 }
1424
1425 EXPORT_SYMBOL(set_current_groups);
1426
1427 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1428 {
1429         int i = 0;
1430
1431         /*
1432          *      SMP: Nobody else can change our grouplist. Thus we are
1433          *      safe.
1434          */
1435
1436         if (gidsetsize < 0)
1437                 return -EINVAL;
1438
1439         /* no need to grab task_lock here; it cannot change */
1440         get_group_info(current->group_info);
1441         i = current->group_info->ngroups;
1442         if (gidsetsize) {
1443                 if (i > gidsetsize) {
1444                         i = -EINVAL;
1445                         goto out;
1446                 }
1447                 if (groups_to_user(grouplist, current->group_info)) {
1448                         i = -EFAULT;
1449                         goto out;
1450                 }
1451         }
1452 out:
1453         put_group_info(current->group_info);
1454         return i;
1455 }
1456
1457 /*
1458  *      SMP: Our groups are copy-on-write. We can set them safely
1459  *      without another task interfering.
1460  */
1461
1462 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1463 {
1464         struct group_info *group_info;
1465         int retval;
1466
1467         if (!capable(CAP_SETGID))
1468                 return -EPERM;
1469         if ((unsigned)gidsetsize > NGROUPS_MAX)
1470                 return -EINVAL;
1471
1472         group_info = groups_alloc(gidsetsize);
1473         if (!group_info)
1474                 return -ENOMEM;
1475         retval = groups_from_user(group_info, grouplist);
1476         if (retval) {
1477                 put_group_info(group_info);
1478                 return retval;
1479         }
1480
1481         retval = set_current_groups(group_info);
1482         put_group_info(group_info);
1483
1484         return retval;
1485 }
1486
1487 /*
1488  * Check whether we're fsgid/egid or in the supplemental group..
1489  */
1490 int in_group_p(gid_t grp)
1491 {
1492         int retval = 1;
1493         if (grp != current->fsgid) {
1494                 get_group_info(current->group_info);
1495                 retval = groups_search(current->group_info, grp);
1496                 put_group_info(current->group_info);
1497         }
1498         return retval;
1499 }
1500
1501 EXPORT_SYMBOL(in_group_p);
1502
1503 int in_egroup_p(gid_t grp)
1504 {
1505         int retval = 1;
1506         if (grp != current->egid) {
1507                 get_group_info(current->group_info);
1508                 retval = groups_search(current->group_info, grp);
1509                 put_group_info(current->group_info);
1510         }
1511         return retval;
1512 }
1513
1514 EXPORT_SYMBOL(in_egroup_p);
1515
1516 DECLARE_RWSEM(uts_sem);
1517
1518 EXPORT_SYMBOL(uts_sem);
1519
1520 asmlinkage long sys_newuname(struct new_utsname __user * name)
1521 {
1522         int errno = 0;
1523
1524         down_read(&uts_sem);
1525         if (copy_to_user(name,&system_utsname,sizeof *name))
1526                 errno = -EFAULT;
1527         up_read(&uts_sem);
1528         return errno;
1529 }
1530
1531 asmlinkage long sys_sethostname(char __user *name, int len)
1532 {
1533         int errno;
1534         char tmp[__NEW_UTS_LEN];
1535
1536         if (!capable(CAP_SYS_ADMIN))
1537                 return -EPERM;
1538         if (len < 0 || len > __NEW_UTS_LEN)
1539                 return -EINVAL;
1540         down_write(&uts_sem);
1541         errno = -EFAULT;
1542         if (!copy_from_user(tmp, name, len)) {
1543                 memcpy(system_utsname.nodename, tmp, len);
1544                 system_utsname.nodename[len] = 0;
1545                 errno = 0;
1546         }
1547         up_write(&uts_sem);
1548         return errno;
1549 }
1550
1551 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1552
1553 asmlinkage long sys_gethostname(char __user *name, int len)
1554 {
1555         int i, errno;
1556
1557         if (len < 0)
1558                 return -EINVAL;
1559         down_read(&uts_sem);
1560         i = 1 + strlen(system_utsname.nodename);
1561         if (i > len)
1562                 i = len;
1563         errno = 0;
1564         if (copy_to_user(name, system_utsname.nodename, i))
1565                 errno = -EFAULT;
1566         up_read(&uts_sem);
1567         return errno;
1568 }
1569
1570 #endif
1571
1572 /*
1573  * Only setdomainname; getdomainname can be implemented by calling
1574  * uname()
1575  */
1576 asmlinkage long sys_setdomainname(char __user *name, int len)
1577 {
1578         int errno;
1579         char tmp[__NEW_UTS_LEN];
1580
1581         if (!capable(CAP_SYS_ADMIN))
1582                 return -EPERM;
1583         if (len < 0 || len > __NEW_UTS_LEN)
1584                 return -EINVAL;
1585
1586         down_write(&uts_sem);
1587         errno = -EFAULT;
1588         if (!copy_from_user(tmp, name, len)) {
1589                 memcpy(system_utsname.domainname, tmp, len);
1590                 system_utsname.domainname[len] = 0;
1591                 errno = 0;
1592         }
1593         up_write(&uts_sem);
1594         return errno;
1595 }
1596
1597 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1598 {
1599         if (resource >= RLIM_NLIMITS)
1600                 return -EINVAL;
1601         else {
1602                 struct rlimit value;
1603                 task_lock(current->group_leader);
1604                 value = current->signal->rlim[resource];
1605                 task_unlock(current->group_leader);
1606                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1607         }
1608 }
1609
1610 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1611
1612 /*
1613  *      Back compatibility for getrlimit. Needed for some apps.
1614  */
1615
1616 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1617 {
1618         struct rlimit x;
1619         if (resource >= RLIM_NLIMITS)
1620                 return -EINVAL;
1621
1622         task_lock(current->group_leader);
1623         x = current->signal->rlim[resource];
1624         task_unlock(current->group_leader);
1625         if(x.rlim_cur > 0x7FFFFFFF)
1626                 x.rlim_cur = 0x7FFFFFFF;
1627         if(x.rlim_max > 0x7FFFFFFF)
1628                 x.rlim_max = 0x7FFFFFFF;
1629         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1630 }
1631
1632 #endif
1633
1634 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1635 {
1636         struct rlimit new_rlim, *old_rlim;
1637         int retval;
1638
1639         if (resource >= RLIM_NLIMITS)
1640                 return -EINVAL;
1641         if(copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1642                 return -EFAULT;
1643        if (new_rlim.rlim_cur > new_rlim.rlim_max)
1644                return -EINVAL;
1645         old_rlim = current->signal->rlim + resource;
1646         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1647             !capable(CAP_SYS_RESOURCE))
1648                 return -EPERM;
1649         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > NR_OPEN)
1650                         return -EPERM;
1651
1652         retval = security_task_setrlimit(resource, &new_rlim);
1653         if (retval)
1654                 return retval;
1655
1656         task_lock(current->group_leader);
1657         *old_rlim = new_rlim;
1658         task_unlock(current->group_leader);
1659
1660         if (resource == RLIMIT_CPU && new_rlim.rlim_cur != RLIM_INFINITY &&
1661             (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
1662              new_rlim.rlim_cur <= cputime_to_secs(
1663                      current->signal->it_prof_expires))) {
1664                 cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur);
1665                 read_lock(&tasklist_lock);
1666                 spin_lock_irq(&current->sighand->siglock);
1667                 set_process_cpu_timer(current, CPUCLOCK_PROF,
1668                                       &cputime, NULL);
1669                 spin_unlock_irq(&current->sighand->siglock);
1670                 read_unlock(&tasklist_lock);
1671         }
1672
1673         return 0;
1674 }
1675
1676 /*
1677  * It would make sense to put struct rusage in the task_struct,
1678  * except that would make the task_struct be *really big*.  After
1679  * task_struct gets moved into malloc'ed memory, it would
1680  * make sense to do this.  It will make moving the rest of the information
1681  * a lot simpler!  (Which we're not doing right now because we're not
1682  * measuring them yet).
1683  *
1684  * This expects to be called with tasklist_lock read-locked or better,
1685  * and the siglock not locked.  It may momentarily take the siglock.
1686  *
1687  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1688  * races with threads incrementing their own counters.  But since word
1689  * reads are atomic, we either get new values or old values and we don't
1690  * care which for the sums.  We always take the siglock to protect reading
1691  * the c* fields from p->signal from races with exit.c updating those
1692  * fields when reaping, so a sample either gets all the additions of a
1693  * given child after it's reaped, or none so this sample is before reaping.
1694  */
1695
1696 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1697 {
1698         struct task_struct *t;
1699         unsigned long flags;
1700         cputime_t utime, stime;
1701
1702         memset((char *) r, 0, sizeof *r);
1703
1704         if (unlikely(!p->signal))
1705                 return;
1706
1707         utime = stime = cputime_zero;
1708
1709         switch (who) {
1710                 case RUSAGE_BOTH:
1711                 case RUSAGE_CHILDREN:
1712                         spin_lock_irqsave(&p->sighand->siglock, flags);
1713                         utime = p->signal->cutime;
1714                         stime = p->signal->cstime;
1715                         r->ru_nvcsw = p->signal->cnvcsw;
1716                         r->ru_nivcsw = p->signal->cnivcsw;
1717                         r->ru_minflt = p->signal->cmin_flt;
1718                         r->ru_majflt = p->signal->cmaj_flt;
1719                         spin_unlock_irqrestore(&p->sighand->siglock, flags);
1720
1721                         if (who == RUSAGE_CHILDREN)
1722                                 break;
1723
1724                 case RUSAGE_SELF:
1725                         utime = cputime_add(utime, p->signal->utime);
1726                         stime = cputime_add(stime, p->signal->stime);
1727                         r->ru_nvcsw += p->signal->nvcsw;
1728                         r->ru_nivcsw += p->signal->nivcsw;
1729                         r->ru_minflt += p->signal->min_flt;
1730                         r->ru_majflt += p->signal->maj_flt;
1731                         t = p;
1732                         do {
1733                                 utime = cputime_add(utime, t->utime);
1734                                 stime = cputime_add(stime, t->stime);
1735                                 r->ru_nvcsw += t->nvcsw;
1736                                 r->ru_nivcsw += t->nivcsw;
1737                                 r->ru_minflt += t->min_flt;
1738                                 r->ru_majflt += t->maj_flt;
1739                                 t = next_thread(t);
1740                         } while (t != p);
1741                         break;
1742
1743                 default:
1744                         BUG();
1745         }
1746
1747         cputime_to_timeval(utime, &r->ru_utime);
1748         cputime_to_timeval(stime, &r->ru_stime);
1749 }
1750
1751 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1752 {
1753         struct rusage r;
1754         read_lock(&tasklist_lock);
1755         k_getrusage(p, who, &r);
1756         read_unlock(&tasklist_lock);
1757         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1758 }
1759
1760 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1761 {
1762         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1763                 return -EINVAL;
1764         return getrusage(current, who, ru);
1765 }
1766
1767 asmlinkage long sys_umask(int mask)
1768 {
1769         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1770         return mask;
1771 }
1772
1773 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1774                           unsigned long arg4, unsigned long arg5)
1775 {
1776         long error;
1777
1778         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1779         if (error)
1780                 return error;
1781
1782         switch (option) {
1783                 case PR_SET_PDEATHSIG:
1784                         if (!valid_signal(arg2)) {
1785                                 error = -EINVAL;
1786                                 break;
1787                         }
1788                         current->pdeath_signal = arg2;
1789                         break;
1790                 case PR_GET_PDEATHSIG:
1791                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1792                         break;
1793                 case PR_GET_DUMPABLE:
1794                         error = current->mm->dumpable;
1795                         break;
1796                 case PR_SET_DUMPABLE:
1797                         if (arg2 < 0 || arg2 > 2) {
1798                                 error = -EINVAL;
1799                                 break;
1800                         }
1801                         current->mm->dumpable = arg2;
1802                         break;
1803
1804                 case PR_SET_UNALIGN:
1805                         error = SET_UNALIGN_CTL(current, arg2);
1806                         break;
1807                 case PR_GET_UNALIGN:
1808                         error = GET_UNALIGN_CTL(current, arg2);
1809                         break;
1810                 case PR_SET_FPEMU:
1811                         error = SET_FPEMU_CTL(current, arg2);
1812                         break;
1813                 case PR_GET_FPEMU:
1814                         error = GET_FPEMU_CTL(current, arg2);
1815                         break;
1816                 case PR_SET_FPEXC:
1817                         error = SET_FPEXC_CTL(current, arg2);
1818                         break;
1819                 case PR_GET_FPEXC:
1820                         error = GET_FPEXC_CTL(current, arg2);
1821                         break;
1822                 case PR_GET_TIMING:
1823                         error = PR_TIMING_STATISTICAL;
1824                         break;
1825                 case PR_SET_TIMING:
1826                         if (arg2 == PR_TIMING_STATISTICAL)
1827                                 error = 0;
1828                         else
1829                                 error = -EINVAL;
1830                         break;
1831
1832                 case PR_GET_KEEPCAPS:
1833                         if (current->keep_capabilities)
1834                                 error = 1;
1835                         break;
1836                 case PR_SET_KEEPCAPS:
1837                         if (arg2 != 0 && arg2 != 1) {
1838                                 error = -EINVAL;
1839                                 break;
1840                         }
1841                         current->keep_capabilities = arg2;
1842                         break;
1843                 case PR_SET_NAME: {
1844                         struct task_struct *me = current;
1845                         unsigned char ncomm[sizeof(me->comm)];
1846
1847                         ncomm[sizeof(me->comm)-1] = 0;
1848                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1849                                                 sizeof(me->comm)-1) < 0)
1850                                 return -EFAULT;
1851                         set_task_comm(me, ncomm);
1852                         return 0;
1853                 }
1854                 case PR_GET_NAME: {
1855                         struct task_struct *me = current;
1856                         unsigned char tcomm[sizeof(me->comm)];
1857
1858                         get_task_comm(tcomm, me);
1859                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1860                                 return -EFAULT;
1861                         return 0;
1862                 }
1863                 default:
1864                         error = -EINVAL;
1865                         break;
1866         }
1867         return error;
1868 }