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   1 /*
   2  *  linux/kernel/sys.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/mm.h>
   9 #include <linux/utsname.h>
  10 #include <linux/mman.h>
  11 #include <linux/smp_lock.h>
  12 #include <linux/notifier.h>
  13 #include <linux/reboot.h>
  14 #include <linux/prctl.h>
  15 #include <linux/highuid.h>
  16 #include <linux/fs.h>
  17 #include <linux/resource.h>
  18 #include <linux/kernel.h>
  19 #include <linux/kexec.h>
  20 #include <linux/workqueue.h>
  21 #include <linux/capability.h>
  22 #include <linux/device.h>
  23 #include <linux/key.h>
  24 #include <linux/times.h>
  25 #include <linux/posix-timers.h>
  26 #include <linux/security.h>
  27 #include <linux/dcookies.h>
  28 #include <linux/suspend.h>
  29 #include <linux/tty.h>
  30 #include <linux/signal.h>
  31 #include <linux/cn_proc.h>
  32 #include <linux/getcpu.h>
  33 #include <linux/task_io_accounting_ops.h>
  34 #include <linux/seccomp.h>
  35 #include <linux/cpu.h>
  36
  37 #include <linux/compat.h>
  38 #include <linux/syscalls.h>
  39 #include <linux/kprobes.h>
  40 #include <linux/user_namespace.h>
  41
  42 #include <asm/uaccess.h>
  43 #include <asm/io.h>
  44 #include <asm/unistd.h>
  45
  46 #ifndef SET_UNALIGN_CTL
  47 # define SET_UNALIGN_CTL(a,b)   (-EINVAL)
  48 #endif
  49 #ifndef GET_UNALIGN_CTL
  50 # define GET_UNALIGN_CTL(a,b)   (-EINVAL)
  51 #endif
  52 #ifndef SET_FPEMU_CTL
  53 # define SET_FPEMU_CTL(a,b)     (-EINVAL)
  54 #endif
  55 #ifndef GET_FPEMU_CTL
  56 # define GET_FPEMU_CTL(a,b)     (-EINVAL)
  57 #endif
  58 #ifndef SET_FPEXC_CTL
  59 # define SET_FPEXC_CTL(a,b)     (-EINVAL)
  60 #endif
  61 #ifndef GET_FPEXC_CTL
  62 # define GET_FPEXC_CTL(a,b)     (-EINVAL)
  63 #endif
  64 #ifndef GET_ENDIAN
  65 # define GET_ENDIAN(a,b)        (-EINVAL)
  66 #endif
  67 #ifndef SET_ENDIAN
  68 # define SET_ENDIAN(a,b)        (-EINVAL)
  69 #endif
  70
  71 /*
  72  * this is where the system-wide overflow UID and GID are defined, for
  73  * architectures that now have 32-bit UID/GID but didn't in the past
  74  */
  75
  76 int overflowuid = DEFAULT_OVERFLOWUID;
  77 int overflowgid = DEFAULT_OVERFLOWGID;
  78
  79 #ifdef CONFIG_UID16
  80 EXPORT_SYMBOL(overflowuid);
  81 EXPORT_SYMBOL(overflowgid);
  82 #endif
  83
  84 /*
  85  * the same as above, but for filesystems which can only store a 16-bit
  86  * UID and GID. as such, this is needed on all architectures
  87  */
  88
  89 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
  90 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID;
  91
  92 EXPORT_SYMBOL(fs_overflowuid);
  93 EXPORT_SYMBOL(fs_overflowgid);
  94
  95 /*
  96  * this indicates whether you can reboot with ctrl-alt-del: the default is yes
  97  */
  98
  99 int C_A_D = 1;
 100 struct pid *cad_pid;
 101 EXPORT_SYMBOL(cad_pid);
 102
 103 /*
 104  * If set, this is used for preparing the system to power off.
 105  */
 106
 107 void (*pm_power_off_prepare)(void);
 108
 109 static int set_one_prio(struct task_struct *p, int niceval, int error)
 110 {
 111         int no_nice;
 112
 113         if (p->uid != current->euid &&
 114                 p->euid != current->euid && !capable(CAP_SYS_NICE)) {
 115                 error = -EPERM;
 116                 goto out;
 117         }
 118         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 119                 error = -EACCES;
 120                 goto out;
 121         }
 122         no_nice = security_task_setnice(p, niceval);
 123         if (no_nice) {
 124                 error = no_nice;
 125                 goto out;
 126         }
 127         if (error == -ESRCH)
 128                 error = 0;
 129         set_user_nice(p, niceval);
 130 out:
 131         return error;
 132 }
 133
 134 asmlinkage long sys_setpriority(int which, int who, int niceval)
 135 {
 136         struct task_struct *g, *p;
 137         struct user_struct *user;
 138         int error = -EINVAL;
 139         struct pid *pgrp;
 140
 141         if (which > PRIO_USER || which < PRIO_PROCESS)
 142                 goto out;
 143
 144         /* normalize: avoid signed division (rounding problems) */
 145         error = -ESRCH;
 146         if (niceval < -20)
 147                 niceval = -20;
 148         if (niceval > 19)
 149                 niceval = 19;
 150
 151         read_lock(&tasklist_lock);
 152         switch (which) {
 153                 case PRIO_PROCESS:
 154                         if (who)
 155                                 p = find_task_by_vpid(who);
 156                         else
 157                                 p = current;
 158                         if (p)
 159                                 error = set_one_prio(p, niceval, error);
 160                         break;
 161                 case PRIO_PGRP:
 162                         if (who)
 163                                 pgrp = find_vpid(who);
 164                         else
 165                                 pgrp = task_pgrp(current);
 166                         do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
 167                                 error = set_one_prio(p, niceval, error);
 168                         } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
 169                         break;
 170                 case PRIO_USER:
 171                         user = current->user;
 172                         if (!who)
 173                                 who = current->uid;
 174                         else
 175                                 if ((who != current->uid) && !(user = find_user(who)))
 176                                         goto out_unlock;        /* No processes for this user */
 177
 178                         do_each_thread(g, p)
 179                                 if (p->uid == who)
 180                                         error = set_one_prio(p, niceval, error);
 181                         while_each_thread(g, p);
 182                         if (who != current->uid)
 183                                 free_uid(user);         /* For find_user() */
 184                         break;
 185         }
 186 out_unlock:
 187         read_unlock(&tasklist_lock);
 188 out:
 189         return error;
 190 }
 191
 192 /*
 193  * Ugh. To avoid negative return values, "getpriority()" will
 194  * not return the normal nice-value, but a negated value that
 195  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 196  * to stay compatible.
 197  */
 198 asmlinkage long sys_getpriority(int which, int who)
 199 {
 200         struct task_struct *g, *p;
 201         struct user_struct *user;
 202         long niceval, retval = -ESRCH;
 203         struct pid *pgrp;
 204
 205         if (which > PRIO_USER || which < PRIO_PROCESS)
 206                 return -EINVAL;
 207
 208         read_lock(&tasklist_lock);
 209         switch (which) {
 210                 case PRIO_PROCESS:
 211                         if (who)
 212                                 p = find_task_by_vpid(who);
 213                         else
 214                                 p = current;
 215                         if (p) {
 216                                 niceval = 20 - task_nice(p);
 217                                 if (niceval > retval)
 218                                         retval = niceval;
 219                         }
 220                         break;
 221                 case PRIO_PGRP:
 222                         if (who)
 223                                 pgrp = find_vpid(who);
 224                         else
 225                                 pgrp = task_pgrp(current);
 226                         do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
 227                                 niceval = 20 - task_nice(p);
 228                                 if (niceval > retval)
 229                                         retval = niceval;
 230                         } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
 231                         break;
 232                 case PRIO_USER:
 233                         user = current->user;
 234                         if (!who)
 235                                 who = current->uid;
 236                         else
 237                                 if ((who != current->uid) && !(user = find_user(who)))
 238                                         goto out_unlock;        /* No processes for this user */
 239
 240                         do_each_thread(g, p)
 241                                 if (p->uid == who) {
 242                                         niceval = 20 - task_nice(p);
 243                                         if (niceval > retval)
 244                                                 retval = niceval;
 245                                 }
 246                         while_each_thread(g, p);
 247                         if (who != current->uid)
 248                                 free_uid(user);         /* for find_user() */
 249                         break;
 250         }
 251 out_unlock:
 252         read_unlock(&tasklist_lock);
 253
 254         return retval;
 255 }
 256
 257 /**
 258  *      emergency_restart - reboot the system
 259  *
 260  *      Without shutting down any hardware or taking any locks
 261  *      reboot the system.  This is called when we know we are in
 262  *      trouble so this is our best effort to reboot.  This is
 263  *      safe to call in interrupt context.
 264  */
 265 void emergency_restart(void)
 266 {
 267         machine_emergency_restart();
 268 }
 269 EXPORT_SYMBOL_GPL(emergency_restart);
 270
 271 static void kernel_restart_prepare(char *cmd)
 272 {
 273         blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 274         system_state = SYSTEM_RESTART;
 275         device_shutdown();
 276         sysdev_shutdown();
 277 }
 278
 279 /**
 280  *      kernel_restart - reboot the system
 281  *      @cmd: pointer to buffer containing command to execute for restart
 282  *              or %NULL
 283  *
 284  *      Shutdown everything and perform a clean reboot.
 285  *      This is not safe to call in interrupt context.
 286  */
 287 void kernel_restart(char *cmd)
 288 {
 289         kernel_restart_prepare(cmd);
 290         if (!cmd)
 291                 printk(KERN_EMERG "Restarting system.\n");
 292         else
 293                 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd);
 294         machine_restart(cmd);
 295 }
 296 EXPORT_SYMBOL_GPL(kernel_restart);
 297
 298 /**
 299  *      kernel_kexec - reboot the system
 300  *
 301  *      Move into place and start executing a preloaded standalone
 302  *      executable.  If nothing was preloaded return an error.
 303  */
 304 static void kernel_kexec(void)
 305 {
 306 #ifdef CONFIG_KEXEC
 307         struct kimage *image;
 308         image = xchg(&kexec_image, NULL);
 309         if (!image)
 310                 return;
 311         kernel_restart_prepare(NULL);
 312         printk(KERN_EMERG "Starting new kernel\n");
 313         machine_shutdown();
 314         machine_kexec(image);
 315 #endif
 316 }
 317
 318 static void kernel_shutdown_prepare(enum system_states state)
 319 {
 320         blocking_notifier_call_chain(&reboot_notifier_list,
 321                 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
 322         system_state = state;
 323         device_shutdown();
 324 }
 325 /**
 326  *      kernel_halt - halt the system
 327  *
 328  *      Shutdown everything and perform a clean system halt.
 329  */
 330 void kernel_halt(void)
 331 {
 332         kernel_shutdown_prepare(SYSTEM_HALT);
 333         sysdev_shutdown();
 334         printk(KERN_EMERG "System halted.\n");
 335         machine_halt();
 336 }
 337
 338 EXPORT_SYMBOL_GPL(kernel_halt);
 339
 340 /**
 341  *      kernel_power_off - power_off the system
 342  *
 343  *      Shutdown everything and perform a clean system power_off.
 344  */
 345 void kernel_power_off(void)
 346 {
 347         kernel_shutdown_prepare(SYSTEM_POWER_OFF);
 348         if (pm_power_off_prepare)
 349                 pm_power_off_prepare();
 350         disable_nonboot_cpus();
 351         sysdev_shutdown();
 352         printk(KERN_EMERG "Power down.\n");
 353         machine_power_off();
 354 }
 355 EXPORT_SYMBOL_GPL(kernel_power_off);
 356 /*
 357  * Reboot system call: for obvious reasons only root may call it,
 358  * and even root needs to set up some magic numbers in the registers
 359  * so that some mistake won't make this reboot the whole machine.
 360  * You can also set the meaning of the ctrl-alt-del-key here.
 361  *
 362  * reboot doesn't sync: do that yourself before calling this.
 363  */
 364 asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user * arg)
 365 {
 366         char buffer[256];
 367
 368         /* We only trust the superuser with rebooting the system. */
 369         if (!capable(CAP_SYS_BOOT))
 370                 return -EPERM;
 371
 372         /* For safety, we require "magic" arguments. */
 373         if (magic1 != LINUX_REBOOT_MAGIC1 ||
 374             (magic2 != LINUX_REBOOT_MAGIC2 &&
 375                         magic2 != LINUX_REBOOT_MAGIC2A &&
 376                         magic2 != LINUX_REBOOT_MAGIC2B &&
 377                         magic2 != LINUX_REBOOT_MAGIC2C))
 378                 return -EINVAL;
 379
 380         /* Instead of trying to make the power_off code look like
 381          * halt when pm_power_off is not set do it the easy way.
 382          */
 383         if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
 384                 cmd = LINUX_REBOOT_CMD_HALT;
 385
 386         lock_kernel();
 387         switch (cmd) {
 388         case LINUX_REBOOT_CMD_RESTART:
 389                 kernel_restart(NULL);
 390                 break;
 391
 392         case LINUX_REBOOT_CMD_CAD_ON:
 393                 C_A_D = 1;
 394                 break;
 395
 396         case LINUX_REBOOT_CMD_CAD_OFF:
 397                 C_A_D = 0;
 398                 break;
 399
 400         case LINUX_REBOOT_CMD_HALT:
 401                 kernel_halt();
 402                 unlock_kernel();
 403                 do_exit(0);
 404                 break;
 405
 406         case LINUX_REBOOT_CMD_POWER_OFF:
 407                 kernel_power_off();
 408                 unlock_kernel();
 409                 do_exit(0);
 410                 break;
 411
 412         case LINUX_REBOOT_CMD_RESTART2:
 413                 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) {
 414                         unlock_kernel();
 415                         return -EFAULT;
 416                 }
 417                 buffer[sizeof(buffer) - 1] = '\0';
 418
 419                 kernel_restart(buffer);
 420                 break;
 421
 422         case LINUX_REBOOT_CMD_KEXEC:
 423                 kernel_kexec();
 424                 unlock_kernel();
 425                 return -EINVAL;
 426
 427 #ifdef CONFIG_HIBERNATION
 428         case LINUX_REBOOT_CMD_SW_SUSPEND:
 429                 {
 430                         int ret = hibernate();
 431                         unlock_kernel();
 432                         return ret;
 433                 }
 434 #endif
 435
 436         default:
 437                 unlock_kernel();
 438                 return -EINVAL;
 439         }
 440         unlock_kernel();
 441         return 0;
 442 }
 443
 444 static void deferred_cad(struct work_struct *dummy)
 445 {
 446         kernel_restart(NULL);
 447 }
 448
 449 /*
 450  * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
 451  * As it's called within an interrupt, it may NOT sync: the only choice
 452  * is whether to reboot at once, or just ignore the ctrl-alt-del.
 453  */
 454 void ctrl_alt_del(void)
 455 {
 456         static DECLARE_WORK(cad_work, deferred_cad);
 457
 458         if (C_A_D)
 459                 schedule_work(&cad_work);
 460         else
 461                 kill_cad_pid(SIGINT, 1);
 462 }
 463
 464 /*
 465  * Unprivileged users may change the real gid to the effective gid
 466  * or vice versa.  (BSD-style)
 467  *
 468  * If you set the real gid at all, or set the effective gid to a value not
 469  * equal to the real gid, then the saved gid is set to the new effective gid.
 470  *
 471  * This makes it possible for a setgid program to completely drop its
 472  * privileges, which is often a useful assertion to make when you are doing
 473  * a security audit over a program.
 474  *
 475  * The general idea is that a program which uses just setregid() will be
 476  * 100% compatible with BSD.  A program which uses just setgid() will be
 477  * 100% compatible with POSIX with saved IDs.
 478  *
 479  * SMP: There are not races, the GIDs are checked only by filesystem
 480  *      operations (as far as semantic preservation is concerned).
 481  */
 482 asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
 483 {
 484         int old_rgid = current->gid;
 485         int old_egid = current->egid;
 486         int new_rgid = old_rgid;
 487         int new_egid = old_egid;
 488         int retval;
 489
 490         retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 491         if (retval)
 492                 return retval;
 493
 494         if (rgid != (gid_t) -1) {
 495                 if ((old_rgid == rgid) ||
 496                     (current->egid==rgid) ||
 497                     capable(CAP_SETGID))
 498                         new_rgid = rgid;
 499                 else
 500                         return -EPERM;
 501         }
 502         if (egid != (gid_t) -1) {
 503                 if ((old_rgid == egid) ||
 504                     (current->egid == egid) ||
 505                     (current->sgid == egid) ||
 506                     capable(CAP_SETGID))
 507                         new_egid = egid;
 508                 else
 509                         return -EPERM;
 510         }
 511         if (new_egid != old_egid) {
 512                 set_dumpable(current->mm, suid_dumpable);
 513                 smp_wmb();
 514         }
 515         if (rgid != (gid_t) -1 ||
 516             (egid != (gid_t) -1 && egid != old_rgid))
 517                 current->sgid = new_egid;
 518         current->fsgid = new_egid;
 519         current->egid = new_egid;
 520         current->gid = new_rgid;
 521         key_fsgid_changed(current);
 522         proc_id_connector(current, PROC_EVENT_GID);
 523         return 0;
 524 }
 525
 526 /*
 527  * setgid() is implemented like SysV w/ SAVED_IDS
 528  *
 529  * SMP: Same implicit races as above.
 530  */
 531 asmlinkage long sys_setgid(gid_t gid)
 532 {
 533         int old_egid = current->egid;
 534         int retval;
 535
 536         retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 537         if (retval)
 538                 return retval;
 539
 540         if (capable(CAP_SETGID)) {
 541                 if (old_egid != gid) {
 542                         set_dumpable(current->mm, suid_dumpable);
 543                         smp_wmb();
 544                 }
 545                 current->gid = current->egid = current->sgid = current->fsgid = gid;
 546         } else if ((gid == current->gid) || (gid == current->sgid)) {
 547                 if (old_egid != gid) {
 548                         set_dumpable(current->mm, suid_dumpable);
 549                         smp_wmb();
 550                 }
 551                 current->egid = current->fsgid = gid;
 552         }
 553         else
 554                 return -EPERM;
 555
 556         key_fsgid_changed(current);
 557         proc_id_connector(current, PROC_EVENT_GID);
 558         return 0;
 559 }
 560
 561 static int set_user(uid_t new_ruid, int dumpclear)
 562 {
 563         struct user_struct *new_user;
 564
 565         new_user = alloc_uid(current->nsproxy->user_ns, new_ruid);
 566         if (!new_user)
 567                 return -EAGAIN;
 568
 569         if (atomic_read(&new_user->processes) >=
 570                                 current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
 571                         new_user != current->nsproxy->user_ns->root_user) {
 572                 free_uid(new_user);
 573                 return -EAGAIN;
 574         }
 575
 576         switch_uid(new_user);
 577
 578         if (dumpclear) {
 579                 set_dumpable(current->mm, suid_dumpable);
 580                 smp_wmb();
 581         }
 582         current->uid = new_ruid;
 583         return 0;
 584 }
 585
 586 /*
 587  * Unprivileged users may change the real uid to the effective uid
 588  * or vice versa.  (BSD-style)
 589  *
 590  * If you set the real uid at all, or set the effective uid to a value not
 591  * equal to the real uid, then the saved uid is set to the new effective uid.
 592  *
 593  * This makes it possible for a setuid program to completely drop its
 594  * privileges, which is often a useful assertion to make when you are doing
 595  * a security audit over a program.
 596  *
 597  * The general idea is that a program which uses just setreuid() will be
 598  * 100% compatible with BSD.  A program which uses just setuid() will be
 599  * 100% compatible with POSIX with saved IDs.
 600  */
 601 asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
 602 {
 603         int old_ruid, old_euid, old_suid, new_ruid, new_euid;
 604         int retval;
 605
 606         retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 607         if (retval)
 608                 return retval;
 609
 610         new_ruid = old_ruid = current->uid;
 611         new_euid = old_euid = current->euid;
 612         old_suid = current->suid;
 613
 614         if (ruid != (uid_t) -1) {
 615                 new_ruid = ruid;
 616                 if ((old_ruid != ruid) &&
 617                     (current->euid != ruid) &&
 618                     !capable(CAP_SETUID))
 619                         return -EPERM;
 620         }
 621
 622         if (euid != (uid_t) -1) {
 623                 new_euid = euid;
 624                 if ((old_ruid != euid) &&
 625                     (current->euid != euid) &&
 626                     (current->suid != euid) &&
 627                     !capable(CAP_SETUID))
 628                         return -EPERM;
 629         }
 630
 631         if (new_ruid != old_ruid && set_user(new_ruid, new_euid != old_euid) < 0)
 632                 return -EAGAIN;
 633
 634         if (new_euid != old_euid) {
 635                 set_dumpable(current->mm, suid_dumpable);
 636                 smp_wmb();
 637         }
 638         current->fsuid = current->euid = new_euid;
 639         if (ruid != (uid_t) -1 ||
 640             (euid != (uid_t) -1 && euid != old_ruid))
 641                 current->suid = current->euid;
 642         current->fsuid = current->euid;
 643
 644         key_fsuid_changed(current);
 645         proc_id_connector(current, PROC_EVENT_UID);
 646
 647         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
 648 }
 649
 650
 651
 652 /*
 653  * setuid() is implemented like SysV with SAVED_IDS
 654  *
 655  * Note that SAVED_ID's is deficient in that a setuid root program
 656  * like sendmail, for example, cannot set its uid to be a normal
 657  * user and then switch back, because if you're root, setuid() sets
 658  * the saved uid too.  If you don't like this, blame the bright people
 659  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 660  * will allow a root program to temporarily drop privileges and be able to
 661  * regain them by swapping the real and effective uid.
 662  */
 663 asmlinkage long sys_setuid(uid_t uid)
 664 {
 665         int old_euid = current->euid;
 666         int old_ruid, old_suid, new_suid;
 667         int retval;
 668
 669         retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 670         if (retval)
 671                 return retval;
 672
 673         old_ruid = current->uid;
 674         old_suid = current->suid;
 675         new_suid = old_suid;
 676
 677         if (capable(CAP_SETUID)) {
 678                 if (uid != old_ruid && set_user(uid, old_euid != uid) < 0)
 679                         return -EAGAIN;
 680                 new_suid = uid;
 681         } else if ((uid != current->uid) && (uid != new_suid))
 682                 return -EPERM;
 683
 684         if (old_euid != uid) {
 685                 set_dumpable(current->mm, suid_dumpable);
 686                 smp_wmb();
 687         }
 688         current->fsuid = current->euid = uid;
 689         current->suid = new_suid;
 690
 691         key_fsuid_changed(current);
 692         proc_id_connector(current, PROC_EVENT_UID);
 693
 694         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
 695 }
 696
 697
 698 /*
 699  * This function implements a generic ability to update ruid, euid,
 700  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 701  */
 702 asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 703 {
 704         int old_ruid = current->uid;
 705         int old_euid = current->euid;
 706         int old_suid = current->suid;
 707         int retval;
 708
 709         retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 710         if (retval)
 711                 return retval;
 712
 713         if (!capable(CAP_SETUID)) {
 714                 if ((ruid != (uid_t) -1) && (ruid != current->uid) &&
 715                     (ruid != current->euid) && (ruid != current->suid))
 716                         return -EPERM;
 717                 if ((euid != (uid_t) -1) && (euid != current->uid) &&
 718                     (euid != current->euid) && (euid != current->suid))
 719                         return -EPERM;
 720                 if ((suid != (uid_t) -1) && (suid != current->uid) &&
 721                     (suid != current->euid) && (suid != current->suid))
 722                         return -EPERM;
 723         }
 724         if (ruid != (uid_t) -1) {
 725                 if (ruid != current->uid && set_user(ruid, euid != current->euid) < 0)
 726                         return -EAGAIN;
 727         }
 728         if (euid != (uid_t) -1) {
 729                 if (euid != current->euid) {
 730                         set_dumpable(current->mm, suid_dumpable);
 731                         smp_wmb();
 732                 }
 733                 current->euid = euid;
 734         }
 735         current->fsuid = current->euid;
 736         if (suid != (uid_t) -1)
 737                 current->suid = suid;
 738
 739         key_fsuid_changed(current);
 740         proc_id_connector(current, PROC_EVENT_UID);
 741
 742         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
 743 }
 744
 745 asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
 746 {
 747         int retval;
 748
 749         if (!(retval = put_user(current->uid, ruid)) &&
 750             !(retval = put_user(current->euid, euid)))
 751                 retval = put_user(current->suid, suid);
 752
 753         return retval;
 754 }
 755
 756 /*
 757  * Same as above, but for rgid, egid, sgid.
 758  */
 759 asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 760 {
 761         int retval;
 762
 763         retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 764         if (retval)
 765                 return retval;
 766
 767         if (!capable(CAP_SETGID)) {
 768                 if ((rgid != (gid_t) -1) && (rgid != current->gid) &&
 769                     (rgid != current->egid) && (rgid != current->sgid))
 770                         return -EPERM;
 771                 if ((egid != (gid_t) -1) && (egid != current->gid) &&
 772                     (egid != current->egid) && (egid != current->sgid))
 773                         return -EPERM;
 774                 if ((sgid != (gid_t) -1) && (sgid != current->gid) &&
 775                     (sgid != current->egid) && (sgid != current->sgid))
 776                         return -EPERM;
 777         }
 778         if (egid != (gid_t) -1) {
 779                 if (egid != current->egid) {
 780                         set_dumpable(current->mm, suid_dumpable);
 781                         smp_wmb();
 782                 }
 783                 current->egid = egid;
 784         }
 785         current->fsgid = current->egid;
 786         if (rgid != (gid_t) -1)
 787                 current->gid = rgid;
 788         if (sgid != (gid_t) -1)
 789                 current->sgid = sgid;
 790
 791         key_fsgid_changed(current);
 792         proc_id_connector(current, PROC_EVENT_GID);
 793         return 0;
 794 }
 795
 796 asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
 797 {
 798         int retval;
 799
 800         if (!(retval = put_user(current->gid, rgid)) &&
 801             !(retval = put_user(current->egid, egid)))
 802                 retval = put_user(current->sgid, sgid);
 803
 804         return retval;
 805 }
 806
 807
 808 /*
 809  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 810  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 811  * whatever uid it wants to). It normally shadows "euid", except when
 812  * explicitly set by setfsuid() or for access..
 813  */
 814 asmlinkage long sys_setfsuid(uid_t uid)
 815 {
 816         int old_fsuid;
 817
 818         old_fsuid = current->fsuid;
 819         if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
 820                 return old_fsuid;
 821
 822         if (uid == current->uid || uid == current->euid ||
 823             uid == current->suid || uid == current->fsuid ||
 824             capable(CAP_SETUID)) {
 825                 if (uid != old_fsuid) {
 826                         set_dumpable(current->mm, suid_dumpable);
 827                         smp_wmb();
 828                 }
 829                 current->fsuid = uid;
 830         }
 831
 832         key_fsuid_changed(current);
 833         proc_id_connector(current, PROC_EVENT_UID);
 834
 835         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
 836
 837         return old_fsuid;
 838 }
 839
 840 /*
 841  * Samma på svenska..
 842  */
 843 asmlinkage long sys_setfsgid(gid_t gid)
 844 {
 845         int old_fsgid;
 846
 847         old_fsgid = current->fsgid;
 848         if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 849                 return old_fsgid;
 850
 851         if (gid == current->gid || gid == current->egid ||
 852             gid == current->sgid || gid == current->fsgid ||
 853             capable(CAP_SETGID)) {
 854                 if (gid != old_fsgid) {
 855                         set_dumpable(current->mm, suid_dumpable);
 856                         smp_wmb();
 857                 }
 858                 current->fsgid = gid;
 859                 key_fsgid_changed(current);
 860                 proc_id_connector(current, PROC_EVENT_GID);
 861         }
 862         return old_fsgid;
 863 }
 864
 865 asmlinkage long sys_times(struct tms __user * tbuf)
 866 {
 867         /*
 868          *      In the SMP world we might just be unlucky and have one of
 869          *      the times increment as we use it. Since the value is an
 870          *      atomically safe type this is just fine. Conceptually its
 871          *      as if the syscall took an instant longer to occur.
 872          */
 873         if (tbuf) {
 874                 struct tms tmp;
 875                 struct task_struct *tsk = current;
 876                 struct task_struct *t;
 877                 cputime_t utime, stime, cutime, cstime;
 878
 879                 spin_lock_irq(&tsk->sighand->siglock);
 880                 utime = tsk->signal->utime;
 881                 stime = tsk->signal->stime;
 882                 t = tsk;
 883                 do {
 884                         utime = cputime_add(utime, t->utime);
 885                         stime = cputime_add(stime, t->stime);
 886                         t = next_thread(t);
 887                 } while (t != tsk);
 888
 889                 cutime = tsk->signal->cutime;
 890                 cstime = tsk->signal->cstime;
 891                 spin_unlock_irq(&tsk->sighand->siglock);
 892
 893                 tmp.tms_utime = cputime_to_clock_t(utime);
 894                 tmp.tms_stime = cputime_to_clock_t(stime);
 895                 tmp.tms_cutime = cputime_to_clock_t(cutime);
 896                 tmp.tms_cstime = cputime_to_clock_t(cstime);
 897                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 898                         return -EFAULT;
 899         }
 900         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 901 }
 902
 903 /*
 904  * This needs some heavy checking ...
 905  * I just haven't the stomach for it. I also don't fully
 906  * understand sessions/pgrp etc. Let somebody who does explain it.
 907  *
 908  * OK, I think I have the protection semantics right.... this is really
 909  * only important on a multi-user system anyway, to make sure one user
 910  * can't send a signal to a process owned by another.  -TYT, 12/12/91
 911  *
 912  * Auch. Had to add the 'did_exec' flag to conform completely to POSIX.
 913  * LBT 04.03.94
 914  */
 915 asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 916 {
 917         struct task_struct *p;
 918         struct task_struct *group_leader = current->group_leader;
 919         struct pid *pgrp;
 920         int err;
 921
 922         if (!pid)
 923                 pid = task_pid_vnr(group_leader);
 924         if (!pgid)
 925                 pgid = pid;
 926         if (pgid < 0)
 927                 return -EINVAL;
 928
 929         /* From this point forward we keep holding onto the tasklist lock
 930          * so that our parent does not change from under us. -DaveM
 931          */
 932         write_lock_irq(&tasklist_lock);
 933
 934         err = -ESRCH;
 935         p = find_task_by_vpid(pid);
 936         if (!p)
 937                 goto out;
 938
 939         err = -EINVAL;
 940         if (!thread_group_leader(p))
 941                 goto out;
 942
 943         if (same_thread_group(p->real_parent, group_leader)) {
 944                 err = -EPERM;
 945                 if (task_session(p) != task_session(group_leader))
 946                         goto out;
 947                 err = -EACCES;
 948                 if (p->did_exec)
 949                         goto out;
 950         } else {
 951                 err = -ESRCH;
 952                 if (p != group_leader)
 953                         goto out;
 954         }
 955
 956         err = -EPERM;
 957         if (p->signal->leader)
 958                 goto out;
 959
 960         pgrp = task_pid(p);
 961         if (pgid != pid) {
 962                 struct task_struct *g;
 963
 964                 pgrp = find_vpid(pgid);
 965                 g = pid_task(pgrp, PIDTYPE_PGID);
 966                 if (!g || task_session(g) != task_session(group_leader))
 967                         goto out;
 968         }
 969
 970         err = security_task_setpgid(p, pgid);
 971         if (err)
 972                 goto out;
 973
 974         if (task_pgrp(p) != pgrp) {
 975                 detach_pid(p, PIDTYPE_PGID);
 976                 attach_pid(p, PIDTYPE_PGID, pgrp);
 977                 set_task_pgrp(p, pid_nr(pgrp));
 978         }
 979
 980         err = 0;
 981 out:
 982         /* All paths lead to here, thus we are safe. -DaveM */
 983         write_unlock_irq(&tasklist_lock);
 984         return err;
 985 }
 986
 987 asmlinkage long sys_getpgid(pid_t pid)
 988 {
 989         if (!pid)
 990                 return task_pgrp_vnr(current);
 991         else {
 992                 int retval;
 993                 struct task_struct *p;
 994                 struct pid_namespace *ns;
 995
 996                 ns = current->nsproxy->pid_ns;
 997
 998                 read_lock(&tasklist_lock);
 999                 p = find_task_by_pid_ns(pid, ns);
1000                 retval = -ESRCH;
1001                 if (p) {
1002                         retval = security_task_getpgid(p);
1003                         if (!retval)
1004                                 retval = task_pgrp_nr_ns(p, ns);
1005                 }
1006                 read_unlock(&tasklist_lock);
1007                 return retval;
1008         }
1009 }
1010
1011 #ifdef __ARCH_WANT_SYS_GETPGRP
1012
1013 asmlinkage long sys_getpgrp(void)
1014 {
1015         /* SMP - assuming writes are word atomic this is fine */
1016         return task_pgrp_vnr(current);
1017 }
1018
1019 #endif
1020
1021 asmlinkage long sys_getsid(pid_t pid)
1022 {
1023         if (!pid)
1024                 return task_session_vnr(current);
1025         else {
1026                 int retval;
1027                 struct task_struct *p;
1028                 struct pid_namespace *ns;
1029
1030                 ns = current->nsproxy->pid_ns;
1031
1032                 read_lock(&tasklist_lock);
1033                 p = find_task_by_pid_ns(pid, ns);
1034                 retval = -ESRCH;
1035                 if (p) {
1036                         retval = security_task_getsid(p);
1037                         if (!retval)
1038                                 retval = task_session_nr_ns(p, ns);
1039                 }
1040                 read_unlock(&tasklist_lock);
1041                 return retval;
1042         }
1043 }
1044
1045 asmlinkage long sys_setsid(void)
1046 {
1047         struct task_struct *group_leader = current->group_leader;
1048         pid_t session;
1049         int err = -EPERM;
1050
1051         write_lock_irq(&tasklist_lock);
1052
1053         /* Fail if I am already a session leader */
1054         if (group_leader->signal->leader)
1055                 goto out;
1056
1057         session = group_leader->pid;
1058         /* Fail if a process group id already exists that equals the
1059          * proposed session id.
1060          *
1061          * Don't check if session id == 1 because kernel threads use this
1062          * session id and so the check will always fail and make it so
1063          * init cannot successfully call setsid.
1064          */
1065         if (session > 1 && find_task_by_pid_type_ns(PIDTYPE_PGID,
1066                                 session, &init_pid_ns))
1067                 goto out;
1068
1069         group_leader->signal->leader = 1;
1070         __set_special_pids(session, session);
1071
1072         spin_lock(&group_leader->sighand->siglock);
1073         group_leader->signal->tty = NULL;
1074         spin_unlock(&group_leader->sighand->siglock);
1075
1076         err = task_pgrp_vnr(group_leader);
1077 out:
1078         write_unlock_irq(&tasklist_lock);
1079         return err;
1080 }
1081
1082 /*
1083  * Supplementary group IDs
1084  */
1085
1086 /* init to 2 - one for init_task, one to ensure it is never freed */
1087 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
1088
1089 struct group_info *groups_alloc(int gidsetsize)
1090 {
1091         struct group_info *group_info;
1092         int nblocks;
1093         int i;
1094
1095         nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
1096         /* Make sure we always allocate at least one indirect block pointer */
1097         nblocks = nblocks ? : 1;
1098         group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
1099         if (!group_info)
1100                 return NULL;
1101         group_info->ngroups = gidsetsize;
1102         group_info->nblocks = nblocks;
1103         atomic_set(&group_info->usage, 1);
1104
1105         if (gidsetsize <= NGROUPS_SMALL)
1106                 group_info->blocks[0] = group_info->small_block;
1107         else {
1108                 for (i = 0; i < nblocks; i++) {
1109                         gid_t *b;
1110                         b = (void *)__get_free_page(GFP_USER);
1111                         if (!b)
1112                                 goto out_undo_partial_alloc;
1113                         group_info->blocks[i] = b;
1114                 }
1115         }
1116         return group_info;
1117
1118 out_undo_partial_alloc:
1119         while (--i >= 0) {
1120                 free_page((unsigned long)group_info->blocks[i]);
1121         }
1122         kfree(group_info);
1123         return NULL;
1124 }
1125
1126 EXPORT_SYMBOL(groups_alloc);
1127
1128 void groups_free(struct group_info *group_info)
1129 {
1130         if (group_info->blocks[0] != group_info->small_block) {
1131                 int i;
1132                 for (i = 0; i < group_info->nblocks; i++)
1133                         free_page((unsigned long)group_info->blocks[i]);
1134         }
1135         kfree(group_info);
1136 }
1137
1138 EXPORT_SYMBOL(groups_free);
1139
1140 /* export the group_info to a user-space array */
1141 static int groups_to_user(gid_t __user *grouplist,
1142     struct group_info *group_info)
1143 {
1144         int i;
1145         unsigned int count = group_info->ngroups;
1146
1147         for (i = 0; i < group_info->nblocks; i++) {
1148                 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1149                 unsigned int len = cp_count * sizeof(*grouplist);
1150
1151                 if (copy_to_user(grouplist, group_info->blocks[i], len))
1152                         return -EFAULT;
1153
1154                 grouplist += NGROUPS_PER_BLOCK;
1155                 count -= cp_count;
1156         }
1157         return 0;
1158 }
1159
1160 /* fill a group_info from a user-space array - it must be allocated already */
1161 static int groups_from_user(struct group_info *group_info,
1162     gid_t __user *grouplist)
1163 {
1164         int i;
1165         unsigned int count = group_info->ngroups;
1166
1167         for (i = 0; i < group_info->nblocks; i++) {
1168                 unsigned int cp_count = min(NGROUPS_PER_BLOCK, count);
1169                 unsigned int len = cp_count * sizeof(*grouplist);
1170
1171                 if (copy_from_user(group_info->blocks[i], grouplist, len))
1172                         return -EFAULT;
1173
1174                 grouplist += NGROUPS_PER_BLOCK;
1175                 count -= cp_count;
1176         }
1177         return 0;
1178 }
1179
1180 /* a simple Shell sort */
1181 static void groups_sort(struct group_info *group_info)
1182 {
1183         int base, max, stride;
1184         int gidsetsize = group_info->ngroups;
1185
1186         for (stride = 1; stride < gidsetsize; stride = 3 * stride + 1)
1187                 ; /* nothing */
1188         stride /= 3;
1189
1190         while (stride) {
1191                 max = gidsetsize - stride;
1192                 for (base = 0; base < max; base++) {
1193                         int left = base;
1194                         int right = left + stride;
1195                         gid_t tmp = GROUP_AT(group_info, right);
1196
1197                         while (left >= 0 && GROUP_AT(group_info, left) > tmp) {
1198                                 GROUP_AT(group_info, right) =
1199                                     GROUP_AT(group_info, left);
1200                                 right = left;
1201                                 left -= stride;
1202                         }
1203                         GROUP_AT(group_info, right) = tmp;
1204                 }
1205                 stride /= 3;
1206         }
1207 }
1208
1209 /* a simple bsearch */
1210 int groups_search(struct group_info *group_info, gid_t grp)
1211 {
1212         unsigned int left, right;
1213
1214         if (!group_info)
1215                 return 0;
1216
1217         left = 0;
1218         right = group_info->ngroups;
1219         while (left < right) {
1220                 unsigned int mid = (left+right)/2;
1221                 int cmp = grp - GROUP_AT(group_info, mid);
1222                 if (cmp > 0)
1223                         left = mid + 1;
1224                 else if (cmp < 0)
1225                         right = mid;
1226                 else
1227                         return 1;
1228         }
1229         return 0;
1230 }
1231
1232 /* validate and set current->group_info */
1233 int set_current_groups(struct group_info *group_info)
1234 {
1235         int retval;
1236         struct group_info *old_info;
1237
1238         retval = security_task_setgroups(group_info);
1239         if (retval)
1240                 return retval;
1241
1242         groups_sort(group_info);
1243         get_group_info(group_info);
1244
1245         task_lock(current);
1246         old_info = current->group_info;
1247         current->group_info = group_info;
1248         task_unlock(current);
1249
1250         put_group_info(old_info);
1251
1252         return 0;
1253 }
1254
1255 EXPORT_SYMBOL(set_current_groups);
1256
1257 asmlinkage long sys_getgroups(int gidsetsize, gid_t __user *grouplist)
1258 {
1259         int i = 0;
1260
1261         /*
1262          *      SMP: Nobody else can change our grouplist. Thus we are
1263          *      safe.
1264          */
1265
1266         if (gidsetsize < 0)
1267                 return -EINVAL;
1268
1269         /* no need to grab task_lock here; it cannot change */
1270         i = current->group_info->ngroups;
1271         if (gidsetsize) {
1272                 if (i > gidsetsize) {
1273                         i = -EINVAL;
1274                         goto out;
1275                 }
1276                 if (groups_to_user(grouplist, current->group_info)) {
1277                         i = -EFAULT;
1278                         goto out;
1279                 }
1280         }
1281 out:
1282         return i;
1283 }
1284
1285 /*
1286  *      SMP: Our groups are copy-on-write. We can set them safely
1287  *      without another task interfering.
1288  */
1289
1290 asmlinkage long sys_setgroups(int gidsetsize, gid_t __user *grouplist)
1291 {
1292         struct group_info *group_info;
1293         int retval;
1294
1295         if (!capable(CAP_SETGID))
1296                 return -EPERM;
1297         if ((unsigned)gidsetsize > NGROUPS_MAX)
1298                 return -EINVAL;
1299
1300         group_info = groups_alloc(gidsetsize);
1301         if (!group_info)
1302                 return -ENOMEM;
1303         retval = groups_from_user(group_info, grouplist);
1304         if (retval) {
1305                 put_group_info(group_info);
1306                 return retval;
1307         }
1308
1309         retval = set_current_groups(group_info);
1310         put_group_info(group_info);
1311
1312         return retval;
1313 }
1314
1315 /*
1316  * Check whether we're fsgid/egid or in the supplemental group..
1317  */
1318 int in_group_p(gid_t grp)
1319 {
1320         int retval = 1;
1321         if (grp != current->fsgid)
1322                 retval = groups_search(current->group_info, grp);
1323         return retval;
1324 }
1325
1326 EXPORT_SYMBOL(in_group_p);
1327
1328 int in_egroup_p(gid_t grp)
1329 {
1330         int retval = 1;
1331         if (grp != current->egid)
1332                 retval = groups_search(current->group_info, grp);
1333         return retval;
1334 }
1335
1336 EXPORT_SYMBOL(in_egroup_p);
1337
1338 DECLARE_RWSEM(uts_sem);
1339
1340 EXPORT_SYMBOL(uts_sem);
1341
1342 asmlinkage long sys_newuname(struct new_utsname __user * name)
1343 {
1344         int errno = 0;
1345
1346         down_read(&uts_sem);
1347         if (copy_to_user(name, utsname(), sizeof *name))
1348                 errno = -EFAULT;
1349         up_read(&uts_sem);
1350         return errno;
1351 }
1352
1353 asmlinkage long sys_sethostname(char __user *name, int len)
1354 {
1355         int errno;
1356         char tmp[__NEW_UTS_LEN];
1357
1358         if (!capable(CAP_SYS_ADMIN))
1359                 return -EPERM;
1360         if (len < 0 || len > __NEW_UTS_LEN)
1361                 return -EINVAL;
1362         down_write(&uts_sem);
1363         errno = -EFAULT;
1364         if (!copy_from_user(tmp, name, len)) {
1365                 memcpy(utsname()->nodename, tmp, len);
1366                 utsname()->nodename[len] = 0;
1367                 errno = 0;
1368         }
1369         up_write(&uts_sem);
1370         return errno;
1371 }
1372
1373 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1374
1375 asmlinkage long sys_gethostname(char __user *name, int len)
1376 {
1377         int i, errno;
1378
1379         if (len < 0)
1380                 return -EINVAL;
1381         down_read(&uts_sem);
1382         i = 1 + strlen(utsname()->nodename);
1383         if (i > len)
1384                 i = len;
1385         errno = 0;
1386         if (copy_to_user(name, utsname()->nodename, i))
1387                 errno = -EFAULT;
1388         up_read(&uts_sem);
1389         return errno;
1390 }
1391
1392 #endif
1393
1394 /*
1395  * Only setdomainname; getdomainname can be implemented by calling
1396  * uname()
1397  */
1398 asmlinkage long sys_setdomainname(char __user *name, int len)
1399 {
1400         int errno;
1401         char tmp[__NEW_UTS_LEN];
1402
1403         if (!capable(CAP_SYS_ADMIN))
1404                 return -EPERM;
1405         if (len < 0 || len > __NEW_UTS_LEN)
1406                 return -EINVAL;
1407
1408         down_write(&uts_sem);
1409         errno = -EFAULT;
1410         if (!copy_from_user(tmp, name, len)) {
1411                 memcpy(utsname()->domainname, tmp, len);
1412                 utsname()->domainname[len] = 0;
1413                 errno = 0;
1414         }
1415         up_write(&uts_sem);
1416         return errno;
1417 }
1418
1419 asmlinkage long sys_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1420 {
1421         if (resource >= RLIM_NLIMITS)
1422                 return -EINVAL;
1423         else {
1424                 struct rlimit value;
1425                 task_lock(current->group_leader);
1426                 value = current->signal->rlim[resource];
1427                 task_unlock(current->group_leader);
1428                 return copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1429         }
1430 }
1431
1432 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1433
1434 /*
1435  *      Back compatibility for getrlimit. Needed for some apps.
1436  */
1437
1438 asmlinkage long sys_old_getrlimit(unsigned int resource, struct rlimit __user *rlim)
1439 {
1440         struct rlimit x;
1441         if (resource >= RLIM_NLIMITS)
1442                 return -EINVAL;
1443
1444         task_lock(current->group_leader);
1445         x = current->signal->rlim[resource];
1446         task_unlock(current->group_leader);
1447         if (x.rlim_cur > 0x7FFFFFFF)
1448                 x.rlim_cur = 0x7FFFFFFF;
1449         if (x.rlim_max > 0x7FFFFFFF)
1450                 x.rlim_max = 0x7FFFFFFF;
1451         return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0;
1452 }
1453
1454 #endif
1455
1456 asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim)
1457 {
1458         struct rlimit new_rlim, *old_rlim;
1459         unsigned long it_prof_secs;
1460         int retval;
1461
1462         if (resource >= RLIM_NLIMITS)
1463                 return -EINVAL;
1464         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1465                 return -EFAULT;
1466         if (new_rlim.rlim_cur > new_rlim.rlim_max)
1467                 return -EINVAL;
1468         old_rlim = current->signal->rlim + resource;
1469         if ((new_rlim.rlim_max > old_rlim->rlim_max) &&
1470             !capable(CAP_SYS_RESOURCE))
1471                 return -EPERM;
1472         if (resource == RLIMIT_NOFILE && new_rlim.rlim_max > sysctl_nr_open)
1473                 return -EPERM;
1474
1475         retval = security_task_setrlimit(resource, &new_rlim);
1476         if (retval)
1477                 return retval;
1478
1479         if (resource == RLIMIT_CPU && new_rlim.rlim_cur == 0) {
1480                 /*
1481                  * The caller is asking for an immediate RLIMIT_CPU
1482                  * expiry.  But we use the zero value to mean "it was
1483                  * never set".  So let's cheat and make it one second
1484                  * instead
1485                  */
1486                 new_rlim.rlim_cur = 1;
1487         }
1488
1489         task_lock(current->group_leader);
1490         *old_rlim = new_rlim;
1491         task_unlock(current->group_leader);
1492
1493         if (resource != RLIMIT_CPU)
1494                 goto out;
1495
1496         /*
1497          * RLIMIT_CPU handling.   Note that the kernel fails to return an error
1498          * code if it rejected the user's attempt to set RLIMIT_CPU.  This is a
1499          * very long-standing error, and fixing it now risks breakage of
1500          * applications, so we live with it
1501          */
1502         if (new_rlim.rlim_cur == RLIM_INFINITY)
1503                 goto out;
1504
1505         it_prof_secs = cputime_to_secs(current->signal->it_prof_expires);
1506         if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) {
1507                 unsigned long rlim_cur = new_rlim.rlim_cur;
1508                 cputime_t cputime;
1509
1510                 cputime = secs_to_cputime(rlim_cur);
1511                 read_lock(&tasklist_lock);
1512                 spin_lock_irq(&current->sighand->siglock);
1513                 set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
1514                 spin_unlock_irq(&current->sighand->siglock);
1515                 read_unlock(&tasklist_lock);
1516         }
1517 out:
1518         return 0;
1519 }
1520
1521 /*
1522  * It would make sense to put struct rusage in the task_struct,
1523  * except that would make the task_struct be *really big*.  After
1524  * task_struct gets moved into malloc'ed memory, it would
1525  * make sense to do this.  It will make moving the rest of the information
1526  * a lot simpler!  (Which we're not doing right now because we're not
1527  * measuring them yet).
1528  *
1529  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1530  * races with threads incrementing their own counters.  But since word
1531  * reads are atomic, we either get new values or old values and we don't
1532  * care which for the sums.  We always take the siglock to protect reading
1533  * the c* fields from p->signal from races with exit.c updating those
1534  * fields when reaping, so a sample either gets all the additions of a
1535  * given child after it's reaped, or none so this sample is before reaping.
1536  *
1537  * Locking:
1538  * We need to take the siglock for CHILDEREN, SELF and BOTH
1539  * for  the cases current multithreaded, non-current single threaded
1540  * non-current multithreaded.  Thread traversal is now safe with
1541  * the siglock held.
1542  * Strictly speaking, we donot need to take the siglock if we are current and
1543  * single threaded,  as no one else can take our signal_struct away, no one
1544  * else can  reap the  children to update signal->c* counters, and no one else
1545  * can race with the signal-> fields. If we do not take any lock, the
1546  * signal-> fields could be read out of order while another thread was just
1547  * exiting. So we should  place a read memory barrier when we avoid the lock.
1548  * On the writer side,  write memory barrier is implied in  __exit_signal
1549  * as __exit_signal releases  the siglock spinlock after updating the signal->
1550  * fields. But we don't do this yet to keep things simple.
1551  *
1552  */
1553
1554 static void k_getrusage(struct task_struct *p, int who, struct rusage *r)
1555 {
1556         struct task_struct *t;
1557         unsigned long flags;
1558         cputime_t utime, stime;
1559
1560         memset((char *) r, 0, sizeof *r);
1561         utime = stime = cputime_zero;
1562
1563         rcu_read_lock();
1564         if (!lock_task_sighand(p, &flags)) {
1565                 rcu_read_unlock();
1566                 return;
1567         }
1568
1569         switch (who) {
1570                 case RUSAGE_BOTH:
1571                 case RUSAGE_CHILDREN:
1572                         utime = p->signal->cutime;
1573                         stime = p->signal->cstime;
1574                         r->ru_nvcsw = p->signal->cnvcsw;
1575                         r->ru_nivcsw = p->signal->cnivcsw;
1576                         r->ru_minflt = p->signal->cmin_flt;
1577                         r->ru_majflt = p->signal->cmaj_flt;
1578                         r->ru_inblock = p->signal->cinblock;
1579                         r->ru_oublock = p->signal->coublock;
1580
1581                         if (who == RUSAGE_CHILDREN)
1582                                 break;
1583
1584                 case RUSAGE_SELF:
1585                         utime = cputime_add(utime, p->signal->utime);
1586                         stime = cputime_add(stime, p->signal->stime);
1587                         r->ru_nvcsw += p->signal->nvcsw;
1588                         r->ru_nivcsw += p->signal->nivcsw;
1589                         r->ru_minflt += p->signal->min_flt;
1590                         r->ru_majflt += p->signal->maj_flt;
1591                         r->ru_inblock += p->signal->inblock;
1592                         r->ru_oublock += p->signal->oublock;
1593                         t = p;
1594                         do {
1595                                 utime = cputime_add(utime, t->utime);
1596                                 stime = cputime_add(stime, t->stime);
1597                                 r->ru_nvcsw += t->nvcsw;
1598                                 r->ru_nivcsw += t->nivcsw;
1599                                 r->ru_minflt += t->min_flt;
1600                                 r->ru_majflt += t->maj_flt;
1601                                 r->ru_inblock += task_io_get_inblock(t);
1602                                 r->ru_oublock += task_io_get_oublock(t);
1603                                 t = next_thread(t);
1604                         } while (t != p);
1605                         break;
1606
1607                 default:
1608                         BUG();
1609         }
1610
1611         unlock_task_sighand(p, &flags);
1612         rcu_read_unlock();
1613
1614         cputime_to_timeval(utime, &r->ru_utime);
1615         cputime_to_timeval(stime, &r->ru_stime);
1616 }
1617
1618 int getrusage(struct task_struct *p, int who, struct rusage __user *ru)
1619 {
1620         struct rusage r;
1621         k_getrusage(p, who, &r);
1622         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1623 }
1624
1625 asmlinkage long sys_getrusage(int who, struct rusage __user *ru)
1626 {
1627         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN)
1628                 return -EINVAL;
1629         return getrusage(current, who, ru);
1630 }
1631
1632 asmlinkage long sys_umask(int mask)
1633 {
1634         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1635         return mask;
1636 }
1637
1638 asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
1639                           unsigned long arg4, unsigned long arg5)
1640 {
1641         long error;
1642
1643         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
1644         if (error)
1645                 return error;
1646
1647         switch (option) {
1648                 case PR_SET_PDEATHSIG:
1649                         if (!valid_signal(arg2)) {
1650                                 error = -EINVAL;
1651                                 break;
1652                         }
1653                         current->pdeath_signal = arg2;
1654                         break;
1655                 case PR_GET_PDEATHSIG:
1656                         error = put_user(current->pdeath_signal, (int __user *)arg2);
1657                         break;
1658                 case PR_GET_DUMPABLE:
1659                         error = get_dumpable(current->mm);
1660                         break;
1661                 case PR_SET_DUMPABLE:
1662                         if (arg2 < 0 || arg2 > 1) {
1663                                 error = -EINVAL;
1664                                 break;
1665                         }
1666                         set_dumpable(current->mm, arg2);
1667                         break;
1668
1669                 case PR_SET_UNALIGN:
1670                         error = SET_UNALIGN_CTL(current, arg2);
1671                         break;
1672                 case PR_GET_UNALIGN:
1673                         error = GET_UNALIGN_CTL(current, arg2);
1674                         break;
1675                 case PR_SET_FPEMU:
1676                         error = SET_FPEMU_CTL(current, arg2);
1677                         break;
1678                 case PR_GET_FPEMU:
1679                         error = GET_FPEMU_CTL(current, arg2);
1680                         break;
1681                 case PR_SET_FPEXC:
1682                         error = SET_FPEXC_CTL(current, arg2);
1683                         break;
1684                 case PR_GET_FPEXC:
1685                         error = GET_FPEXC_CTL(current, arg2);
1686                         break;
1687                 case PR_GET_TIMING:
1688                         error = PR_TIMING_STATISTICAL;
1689                         break;
1690                 case PR_SET_TIMING:
1691                         if (arg2 == PR_TIMING_STATISTICAL)
1692                                 error = 0;
1693                         else
1694                                 error = -EINVAL;
1695                         break;
1696
1697                 case PR_GET_KEEPCAPS:
1698                         if (current->keep_capabilities)
1699                                 error = 1;
1700                         break;
1701                 case PR_SET_KEEPCAPS:
1702                         if (arg2 != 0 && arg2 != 1) {
1703                                 error = -EINVAL;
1704                                 break;
1705                         }
1706                         current->keep_capabilities = arg2;
1707                         break;
1708                 case PR_SET_NAME: {
1709                         struct task_struct *me = current;
1710                         unsigned char ncomm[sizeof(me->comm)];
1711
1712                         ncomm[sizeof(me->comm)-1] = 0;
1713                         if (strncpy_from_user(ncomm, (char __user *)arg2,
1714                                                 sizeof(me->comm)-1) < 0)
1715                                 return -EFAULT;
1716                         set_task_comm(me, ncomm);
1717                         return 0;
1718                 }
1719                 case PR_GET_NAME: {
1720                         struct task_struct *me = current;
1721                         unsigned char tcomm[sizeof(me->comm)];
1722
1723                         get_task_comm(tcomm, me);
1724                         if (copy_to_user((char __user *)arg2, tcomm, sizeof(tcomm)))
1725                                 return -EFAULT;
1726                         return 0;
1727                 }
1728                 case PR_GET_ENDIAN:
1729                         error = GET_ENDIAN(current, arg2);
1730                         break;
1731                 case PR_SET_ENDIAN:
1732                         error = SET_ENDIAN(current, arg2);
1733                         break;
1734
1735                 case PR_GET_SECCOMP:
1736                         error = prctl_get_seccomp();
1737                         break;
1738                 case PR_SET_SECCOMP:
1739                         error = prctl_set_seccomp(arg2);
1740                         break;
1741
1742                 case PR_CAPBSET_READ:
1743                         if (!cap_valid(arg2))
1744                                 return -EINVAL;
1745                         return !!cap_raised(current->cap_bset, arg2);
1746                 case PR_CAPBSET_DROP:
1747 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
1748                         return cap_prctl_drop(arg2);
1749 #else
1750                         return -EINVAL;
1751 #endif
1752
1753                 default:
1754                         error = -EINVAL;
1755                         break;
1756         }
1757         return error;
1758 }
1759
1760 asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
1761                            struct getcpu_cache __user *unused)
1762 {
1763         int err = 0;
1764         int cpu = raw_smp_processor_id();
1765         if (cpup)
1766                 err |= put_user(cpu, cpup);
1767         if (nodep)
1768                 err |= put_user(cpu_to_node(cpu), nodep);
1769         return err ? -EFAULT : 0;
1770 }
1771
1772 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
1773
1774 static void argv_cleanup(char **argv, char **envp)
1775 {
1776         argv_free(argv);
1777 }
1778
1779 /**
1780  * orderly_poweroff - Trigger an orderly system poweroff
1781  * @force: force poweroff if command execution fails
1782  *
1783  * This may be called from any context to trigger a system shutdown.
1784  * If the orderly shutdown fails, it will force an immediate shutdown.
1785  */
1786 int orderly_poweroff(bool force)
1787 {
1788         int argc;
1789         char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
1790         static char *envp[] = {
1791                 "HOME=/",
1792                 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
1793                 NULL
1794         };
1795         int ret = -ENOMEM;
1796         struct subprocess_info *info;
1797
1798         if (argv == NULL) {
1799                 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
1800                        __func__, poweroff_cmd);
1801                 goto out;
1802         }
1803
1804         info = call_usermodehelper_setup(argv[0], argv, envp);
1805         if (info == NULL) {
1806                 argv_free(argv);
1807                 goto out;
1808         }
1809
1810         call_usermodehelper_setcleanup(info, argv_cleanup);
1811
1812         ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
1813
1814   out:
1815         if (ret && force) {
1816                 printk(KERN_WARNING "Failed to start orderly shutdown: "
1817                        "forcing the issue\n");
1818
1819                 /* I guess this should try to kick off some daemon to
1820                    sync and poweroff asap.  Or not even bother syncing
1821                    if we're doing an emergency shutdown? */
1822                 emergency_sync();
1823                 kernel_power_off();
1824         }
1825
1826         return ret;
1827 }
1828 EXPORT_SYMBOL_GPL(orderly_poweroff);