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