1 /* 2 * linux/kernel/sys.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 #include <linux/export.h> 8 #include <linux/mm.h> 9 #include <linux/utsname.h> 10 #include <linux/mman.h> 11 #include <linux/reboot.h> 12 #include <linux/prctl.h> 13 #include <linux/highuid.h> 14 #include <linux/fs.h> 15 #include <linux/kmod.h> 16 #include <linux/perf_event.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 #include <linux/personality.h> 37 #include <linux/ptrace.h> 38 #include <linux/fs_struct.h> 39 #include <linux/file.h> 40 #include <linux/mount.h> 41 #include <linux/gfp.h> 42 #include <linux/syscore_ops.h> 43 #include <linux/version.h> 44 #include <linux/ctype.h> 45 46 #include <linux/compat.h> 47 #include <linux/syscalls.h> 48 #include <linux/kprobes.h> 49 #include <linux/user_namespace.h> 50 51 #include <linux/kmsg_dump.h> 52 /* Move somewhere else to avoid recompiling? */ 53 #include <generated/utsrelease.h> 54 55 #include <asm/uaccess.h> 56 #include <asm/io.h> 57 #include <asm/unistd.h> 58 59 #ifndef SET_UNALIGN_CTL 60 # define SET_UNALIGN_CTL(a,b) (-EINVAL) 61 #endif 62 #ifndef GET_UNALIGN_CTL 63 # define GET_UNALIGN_CTL(a,b) (-EINVAL) 64 #endif 65 #ifndef SET_FPEMU_CTL 66 # define SET_FPEMU_CTL(a,b) (-EINVAL) 67 #endif 68 #ifndef GET_FPEMU_CTL 69 # define GET_FPEMU_CTL(a,b) (-EINVAL) 70 #endif 71 #ifndef SET_FPEXC_CTL 72 # define SET_FPEXC_CTL(a,b) (-EINVAL) 73 #endif 74 #ifndef GET_FPEXC_CTL 75 # define GET_FPEXC_CTL(a,b) (-EINVAL) 76 #endif 77 #ifndef GET_ENDIAN 78 # define GET_ENDIAN(a,b) (-EINVAL) 79 #endif 80 #ifndef SET_ENDIAN 81 # define SET_ENDIAN(a,b) (-EINVAL) 82 #endif 83 #ifndef GET_TSC_CTL 84 # define GET_TSC_CTL(a) (-EINVAL) 85 #endif 86 #ifndef SET_TSC_CTL 87 # define SET_TSC_CTL(a) (-EINVAL) 88 #endif 89 90 /* 91 * this is where the system-wide overflow UID and GID are defined, for 92 * architectures that now have 32-bit UID/GID but didn't in the past 93 */ 94 95 int overflowuid = DEFAULT_OVERFLOWUID; 96 int overflowgid = DEFAULT_OVERFLOWGID; 97 98 EXPORT_SYMBOL(overflowuid); 99 EXPORT_SYMBOL(overflowgid); 100 101 /* 102 * the same as above, but for filesystems which can only store a 16-bit 103 * UID and GID. as such, this is needed on all architectures 104 */ 105 106 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID; 107 int fs_overflowgid = DEFAULT_FS_OVERFLOWUID; 108 109 EXPORT_SYMBOL(fs_overflowuid); 110 EXPORT_SYMBOL(fs_overflowgid); 111 112 /* 113 * this indicates whether you can reboot with ctrl-alt-del: the default is yes 114 */ 115 116 int C_A_D = 1; 117 struct pid *cad_pid; 118 EXPORT_SYMBOL(cad_pid); 119 120 /* 121 * If set, this is used for preparing the system to power off. 122 */ 123 124 void (*pm_power_off_prepare)(void); 125 126 /* 127 * Returns true if current's euid is same as p's uid or euid, 128 * or has CAP_SYS_NICE to p's user_ns. 129 * 130 * Called with rcu_read_lock, creds are safe 131 */ 132 static bool set_one_prio_perm(struct task_struct *p) 133 { 134 const struct cred *cred = current_cred(), *pcred = __task_cred(p); 135 136 if (uid_eq(pcred->uid, cred->euid) || 137 uid_eq(pcred->euid, cred->euid)) 138 return true; 139 if (ns_capable(pcred->user_ns, CAP_SYS_NICE)) 140 return true; 141 return false; 142 } 143 144 /* 145 * set the priority of a task 146 * - the caller must hold the RCU read lock 147 */ 148 static int set_one_prio(struct task_struct *p, int niceval, int error) 149 { 150 int no_nice; 151 152 if (!set_one_prio_perm(p)) { 153 error = -EPERM; 154 goto out; 155 } 156 if (niceval < task_nice(p) && !can_nice(p, niceval)) { 157 error = -EACCES; 158 goto out; 159 } 160 no_nice = security_task_setnice(p, niceval); 161 if (no_nice) { 162 error = no_nice; 163 goto out; 164 } 165 if (error == -ESRCH) 166 error = 0; 167 set_user_nice(p, niceval); 168 out: 169 return error; 170 } 171 172 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval) 173 { 174 struct task_struct *g, *p; 175 struct user_struct *user; 176 const struct cred *cred = current_cred(); 177 int error = -EINVAL; 178 struct pid *pgrp; 179 kuid_t uid; 180 181 if (which > PRIO_USER || which < PRIO_PROCESS) 182 goto out; 183 184 /* normalize: avoid signed division (rounding problems) */ 185 error = -ESRCH; 186 if (niceval < -20) 187 niceval = -20; 188 if (niceval > 19) 189 niceval = 19; 190 191 rcu_read_lock(); 192 read_lock(&tasklist_lock); 193 switch (which) { 194 case PRIO_PROCESS: 195 if (who) 196 p = find_task_by_vpid(who); 197 else 198 p = current; 199 if (p) 200 error = set_one_prio(p, niceval, error); 201 break; 202 case PRIO_PGRP: 203 if (who) 204 pgrp = find_vpid(who); 205 else 206 pgrp = task_pgrp(current); 207 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { 208 error = set_one_prio(p, niceval, error); 209 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); 210 break; 211 case PRIO_USER: 212 uid = make_kuid(cred->user_ns, who); 213 user = cred->user; 214 if (!who) 215 uid = cred->uid; 216 else if (!uid_eq(uid, cred->uid) && 217 !(user = find_user(uid))) 218 goto out_unlock; /* No processes for this user */ 219 220 do_each_thread(g, p) { 221 if (uid_eq(task_uid(p), uid)) 222 error = set_one_prio(p, niceval, error); 223 } while_each_thread(g, p); 224 if (!uid_eq(uid, cred->uid)) 225 free_uid(user); /* For find_user() */ 226 break; 227 } 228 out_unlock: 229 read_unlock(&tasklist_lock); 230 rcu_read_unlock(); 231 out: 232 return error; 233 } 234 235 /* 236 * Ugh. To avoid negative return values, "getpriority()" will 237 * not return the normal nice-value, but a negated value that 238 * has been offset by 20 (ie it returns 40..1 instead of -20..19) 239 * to stay compatible. 240 */ 241 SYSCALL_DEFINE2(getpriority, int, which, int, who) 242 { 243 struct task_struct *g, *p; 244 struct user_struct *user; 245 const struct cred *cred = current_cred(); 246 long niceval, retval = -ESRCH; 247 struct pid *pgrp; 248 kuid_t uid; 249 250 if (which > PRIO_USER || which < PRIO_PROCESS) 251 return -EINVAL; 252 253 rcu_read_lock(); 254 read_lock(&tasklist_lock); 255 switch (which) { 256 case PRIO_PROCESS: 257 if (who) 258 p = find_task_by_vpid(who); 259 else 260 p = current; 261 if (p) { 262 niceval = 20 - task_nice(p); 263 if (niceval > retval) 264 retval = niceval; 265 } 266 break; 267 case PRIO_PGRP: 268 if (who) 269 pgrp = find_vpid(who); 270 else 271 pgrp = task_pgrp(current); 272 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { 273 niceval = 20 - task_nice(p); 274 if (niceval > retval) 275 retval = niceval; 276 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); 277 break; 278 case PRIO_USER: 279 uid = make_kuid(cred->user_ns, who); 280 user = cred->user; 281 if (!who) 282 uid = cred->uid; 283 else if (!uid_eq(uid, cred->uid) && 284 !(user = find_user(uid))) 285 goto out_unlock; /* No processes for this user */ 286 287 do_each_thread(g, p) { 288 if (uid_eq(task_uid(p), uid)) { 289 niceval = 20 - task_nice(p); 290 if (niceval > retval) 291 retval = niceval; 292 } 293 } while_each_thread(g, p); 294 if (!uid_eq(uid, cred->uid)) 295 free_uid(user); /* for find_user() */ 296 break; 297 } 298 out_unlock: 299 read_unlock(&tasklist_lock); 300 rcu_read_unlock(); 301 302 return retval; 303 } 304 305 /** 306 * emergency_restart - reboot the system 307 * 308 * Without shutting down any hardware or taking any locks 309 * reboot the system. This is called when we know we are in 310 * trouble so this is our best effort to reboot. This is 311 * safe to call in interrupt context. 312 */ 313 void emergency_restart(void) 314 { 315 kmsg_dump(KMSG_DUMP_EMERG); 316 machine_emergency_restart(); 317 } 318 EXPORT_SYMBOL_GPL(emergency_restart); 319 320 void kernel_restart_prepare(char *cmd) 321 { 322 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); 323 system_state = SYSTEM_RESTART; 324 usermodehelper_disable(); 325 device_shutdown(); 326 syscore_shutdown(); 327 } 328 329 /** 330 * register_reboot_notifier - Register function to be called at reboot time 331 * @nb: Info about notifier function to be called 332 * 333 * Registers a function with the list of functions 334 * to be called at reboot time. 335 * 336 * Currently always returns zero, as blocking_notifier_chain_register() 337 * always returns zero. 338 */ 339 int register_reboot_notifier(struct notifier_block *nb) 340 { 341 return blocking_notifier_chain_register(&reboot_notifier_list, nb); 342 } 343 EXPORT_SYMBOL(register_reboot_notifier); 344 345 /** 346 * unregister_reboot_notifier - Unregister previously registered reboot notifier 347 * @nb: Hook to be unregistered 348 * 349 * Unregisters a previously registered reboot 350 * notifier function. 351 * 352 * Returns zero on success, or %-ENOENT on failure. 353 */ 354 int unregister_reboot_notifier(struct notifier_block *nb) 355 { 356 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb); 357 } 358 EXPORT_SYMBOL(unregister_reboot_notifier); 359 360 /** 361 * kernel_restart - reboot the system 362 * @cmd: pointer to buffer containing command to execute for restart 363 * or %NULL 364 * 365 * Shutdown everything and perform a clean reboot. 366 * This is not safe to call in interrupt context. 367 */ 368 void kernel_restart(char *cmd) 369 { 370 kernel_restart_prepare(cmd); 371 disable_nonboot_cpus(); 372 if (!cmd) 373 printk(KERN_EMERG "Restarting system.\n"); 374 else 375 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); 376 kmsg_dump(KMSG_DUMP_RESTART); 377 machine_restart(cmd); 378 } 379 EXPORT_SYMBOL_GPL(kernel_restart); 380 381 static void kernel_shutdown_prepare(enum system_states state) 382 { 383 blocking_notifier_call_chain(&reboot_notifier_list, 384 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL); 385 system_state = state; 386 usermodehelper_disable(); 387 device_shutdown(); 388 } 389 /** 390 * kernel_halt - halt the system 391 * 392 * Shutdown everything and perform a clean system halt. 393 */ 394 void kernel_halt(void) 395 { 396 kernel_shutdown_prepare(SYSTEM_HALT); 397 syscore_shutdown(); 398 printk(KERN_EMERG "System halted.\n"); 399 kmsg_dump(KMSG_DUMP_HALT); 400 machine_halt(); 401 } 402 403 EXPORT_SYMBOL_GPL(kernel_halt); 404 405 /** 406 * kernel_power_off - power_off the system 407 * 408 * Shutdown everything and perform a clean system power_off. 409 */ 410 void kernel_power_off(void) 411 { 412 kernel_shutdown_prepare(SYSTEM_POWER_OFF); 413 if (pm_power_off_prepare) 414 pm_power_off_prepare(); 415 disable_nonboot_cpus(); 416 syscore_shutdown(); 417 printk(KERN_EMERG "Power down.\n"); 418 kmsg_dump(KMSG_DUMP_POWEROFF); 419 machine_power_off(); 420 } 421 EXPORT_SYMBOL_GPL(kernel_power_off); 422 423 static DEFINE_MUTEX(reboot_mutex); 424 425 /* 426 * Reboot system call: for obvious reasons only root may call it, 427 * and even root needs to set up some magic numbers in the registers 428 * so that some mistake won't make this reboot the whole machine. 429 * You can also set the meaning of the ctrl-alt-del-key here. 430 * 431 * reboot doesn't sync: do that yourself before calling this. 432 */ 433 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, 434 void __user *, arg) 435 { 436 char buffer[256]; 437 int ret = 0; 438 439 /* We only trust the superuser with rebooting the system. */ 440 if (!capable(CAP_SYS_BOOT)) 441 return -EPERM; 442 443 /* For safety, we require "magic" arguments. */ 444 if (magic1 != LINUX_REBOOT_MAGIC1 || 445 (magic2 != LINUX_REBOOT_MAGIC2 && 446 magic2 != LINUX_REBOOT_MAGIC2A && 447 magic2 != LINUX_REBOOT_MAGIC2B && 448 magic2 != LINUX_REBOOT_MAGIC2C)) 449 return -EINVAL; 450 451 /* 452 * If pid namespaces are enabled and the current task is in a child 453 * pid_namespace, the command is handled by reboot_pid_ns() which will 454 * call do_exit(). 455 */ 456 ret = reboot_pid_ns(task_active_pid_ns(current), cmd); 457 if (ret) 458 return ret; 459 460 /* Instead of trying to make the power_off code look like 461 * halt when pm_power_off is not set do it the easy way. 462 */ 463 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) 464 cmd = LINUX_REBOOT_CMD_HALT; 465 466 mutex_lock(&reboot_mutex); 467 switch (cmd) { 468 case LINUX_REBOOT_CMD_RESTART: 469 kernel_restart(NULL); 470 break; 471 472 case LINUX_REBOOT_CMD_CAD_ON: 473 C_A_D = 1; 474 break; 475 476 case LINUX_REBOOT_CMD_CAD_OFF: 477 C_A_D = 0; 478 break; 479 480 case LINUX_REBOOT_CMD_HALT: 481 kernel_halt(); 482 do_exit(0); 483 panic("cannot halt"); 484 485 case LINUX_REBOOT_CMD_POWER_OFF: 486 kernel_power_off(); 487 do_exit(0); 488 break; 489 490 case LINUX_REBOOT_CMD_RESTART2: 491 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { 492 ret = -EFAULT; 493 break; 494 } 495 buffer[sizeof(buffer) - 1] = '\0'; 496 497 kernel_restart(buffer); 498 break; 499 500 #ifdef CONFIG_KEXEC 501 case LINUX_REBOOT_CMD_KEXEC: 502 ret = kernel_kexec(); 503 break; 504 #endif 505 506 #ifdef CONFIG_HIBERNATION 507 case LINUX_REBOOT_CMD_SW_SUSPEND: 508 ret = hibernate(); 509 break; 510 #endif 511 512 default: 513 ret = -EINVAL; 514 break; 515 } 516 mutex_unlock(&reboot_mutex); 517 return ret; 518 } 519 520 static void deferred_cad(struct work_struct *dummy) 521 { 522 kernel_restart(NULL); 523 } 524 525 /* 526 * This function gets called by ctrl-alt-del - ie the keyboard interrupt. 527 * As it's called within an interrupt, it may NOT sync: the only choice 528 * is whether to reboot at once, or just ignore the ctrl-alt-del. 529 */ 530 void ctrl_alt_del(void) 531 { 532 static DECLARE_WORK(cad_work, deferred_cad); 533 534 if (C_A_D) 535 schedule_work(&cad_work); 536 else 537 kill_cad_pid(SIGINT, 1); 538 } 539 540 /* 541 * Unprivileged users may change the real gid to the effective gid 542 * or vice versa. (BSD-style) 543 * 544 * If you set the real gid at all, or set the effective gid to a value not 545 * equal to the real gid, then the saved gid is set to the new effective gid. 546 * 547 * This makes it possible for a setgid program to completely drop its 548 * privileges, which is often a useful assertion to make when you are doing 549 * a security audit over a program. 550 * 551 * The general idea is that a program which uses just setregid() will be 552 * 100% compatible with BSD. A program which uses just setgid() will be 553 * 100% compatible with POSIX with saved IDs. 554 * 555 * SMP: There are not races, the GIDs are checked only by filesystem 556 * operations (as far as semantic preservation is concerned). 557 */ 558 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid) 559 { 560 struct user_namespace *ns = current_user_ns(); 561 const struct cred *old; 562 struct cred *new; 563 int retval; 564 kgid_t krgid, kegid; 565 566 krgid = make_kgid(ns, rgid); 567 kegid = make_kgid(ns, egid); 568 569 if ((rgid != (gid_t) -1) && !gid_valid(krgid)) 570 return -EINVAL; 571 if ((egid != (gid_t) -1) && !gid_valid(kegid)) 572 return -EINVAL; 573 574 new = prepare_creds(); 575 if (!new) 576 return -ENOMEM; 577 old = current_cred(); 578 579 retval = -EPERM; 580 if (rgid != (gid_t) -1) { 581 if (gid_eq(old->gid, krgid) || 582 gid_eq(old->egid, krgid) || 583 nsown_capable(CAP_SETGID)) 584 new->gid = krgid; 585 else 586 goto error; 587 } 588 if (egid != (gid_t) -1) { 589 if (gid_eq(old->gid, kegid) || 590 gid_eq(old->egid, kegid) || 591 gid_eq(old->sgid, kegid) || 592 nsown_capable(CAP_SETGID)) 593 new->egid = kegid; 594 else 595 goto error; 596 } 597 598 if (rgid != (gid_t) -1 || 599 (egid != (gid_t) -1 && !gid_eq(kegid, old->gid))) 600 new->sgid = new->egid; 601 new->fsgid = new->egid; 602 603 return commit_creds(new); 604 605 error: 606 abort_creds(new); 607 return retval; 608 } 609 610 /* 611 * setgid() is implemented like SysV w/ SAVED_IDS 612 * 613 * SMP: Same implicit races as above. 614 */ 615 SYSCALL_DEFINE1(setgid, gid_t, gid) 616 { 617 struct user_namespace *ns = current_user_ns(); 618 const struct cred *old; 619 struct cred *new; 620 int retval; 621 kgid_t kgid; 622 623 kgid = make_kgid(ns, gid); 624 if (!gid_valid(kgid)) 625 return -EINVAL; 626 627 new = prepare_creds(); 628 if (!new) 629 return -ENOMEM; 630 old = current_cred(); 631 632 retval = -EPERM; 633 if (nsown_capable(CAP_SETGID)) 634 new->gid = new->egid = new->sgid = new->fsgid = kgid; 635 else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) 636 new->egid = new->fsgid = kgid; 637 else 638 goto error; 639 640 return commit_creds(new); 641 642 error: 643 abort_creds(new); 644 return retval; 645 } 646 647 /* 648 * change the user struct in a credentials set to match the new UID 649 */ 650 static int set_user(struct cred *new) 651 { 652 struct user_struct *new_user; 653 654 new_user = alloc_uid(new->uid); 655 if (!new_user) 656 return -EAGAIN; 657 658 /* 659 * We don't fail in case of NPROC limit excess here because too many 660 * poorly written programs don't check set*uid() return code, assuming 661 * it never fails if called by root. We may still enforce NPROC limit 662 * for programs doing set*uid()+execve() by harmlessly deferring the 663 * failure to the execve() stage. 664 */ 665 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) && 666 new_user != INIT_USER) 667 current->flags |= PF_NPROC_EXCEEDED; 668 else 669 current->flags &= ~PF_NPROC_EXCEEDED; 670 671 free_uid(new->user); 672 new->user = new_user; 673 return 0; 674 } 675 676 /* 677 * Unprivileged users may change the real uid to the effective uid 678 * or vice versa. (BSD-style) 679 * 680 * If you set the real uid at all, or set the effective uid to a value not 681 * equal to the real uid, then the saved uid is set to the new effective uid. 682 * 683 * This makes it possible for a setuid program to completely drop its 684 * privileges, which is often a useful assertion to make when you are doing 685 * a security audit over a program. 686 * 687 * The general idea is that a program which uses just setreuid() will be 688 * 100% compatible with BSD. A program which uses just setuid() will be 689 * 100% compatible with POSIX with saved IDs. 690 */ 691 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid) 692 { 693 struct user_namespace *ns = current_user_ns(); 694 const struct cred *old; 695 struct cred *new; 696 int retval; 697 kuid_t kruid, keuid; 698 699 kruid = make_kuid(ns, ruid); 700 keuid = make_kuid(ns, euid); 701 702 if ((ruid != (uid_t) -1) && !uid_valid(kruid)) 703 return -EINVAL; 704 if ((euid != (uid_t) -1) && !uid_valid(keuid)) 705 return -EINVAL; 706 707 new = prepare_creds(); 708 if (!new) 709 return -ENOMEM; 710 old = current_cred(); 711 712 retval = -EPERM; 713 if (ruid != (uid_t) -1) { 714 new->uid = kruid; 715 if (!uid_eq(old->uid, kruid) && 716 !uid_eq(old->euid, kruid) && 717 !nsown_capable(CAP_SETUID)) 718 goto error; 719 } 720 721 if (euid != (uid_t) -1) { 722 new->euid = keuid; 723 if (!uid_eq(old->uid, keuid) && 724 !uid_eq(old->euid, keuid) && 725 !uid_eq(old->suid, keuid) && 726 !nsown_capable(CAP_SETUID)) 727 goto error; 728 } 729 730 if (!uid_eq(new->uid, old->uid)) { 731 retval = set_user(new); 732 if (retval < 0) 733 goto error; 734 } 735 if (ruid != (uid_t) -1 || 736 (euid != (uid_t) -1 && !uid_eq(keuid, old->uid))) 737 new->suid = new->euid; 738 new->fsuid = new->euid; 739 740 retval = security_task_fix_setuid(new, old, LSM_SETID_RE); 741 if (retval < 0) 742 goto error; 743 744 return commit_creds(new); 745 746 error: 747 abort_creds(new); 748 return retval; 749 } 750 751 /* 752 * setuid() is implemented like SysV with SAVED_IDS 753 * 754 * Note that SAVED_ID's is deficient in that a setuid root program 755 * like sendmail, for example, cannot set its uid to be a normal 756 * user and then switch back, because if you're root, setuid() sets 757 * the saved uid too. If you don't like this, blame the bright people 758 * in the POSIX committee and/or USG. Note that the BSD-style setreuid() 759 * will allow a root program to temporarily drop privileges and be able to 760 * regain them by swapping the real and effective uid. 761 */ 762 SYSCALL_DEFINE1(setuid, uid_t, uid) 763 { 764 struct user_namespace *ns = current_user_ns(); 765 const struct cred *old; 766 struct cred *new; 767 int retval; 768 kuid_t kuid; 769 770 kuid = make_kuid(ns, uid); 771 if (!uid_valid(kuid)) 772 return -EINVAL; 773 774 new = prepare_creds(); 775 if (!new) 776 return -ENOMEM; 777 old = current_cred(); 778 779 retval = -EPERM; 780 if (nsown_capable(CAP_SETUID)) { 781 new->suid = new->uid = kuid; 782 if (!uid_eq(kuid, old->uid)) { 783 retval = set_user(new); 784 if (retval < 0) 785 goto error; 786 } 787 } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) { 788 goto error; 789 } 790 791 new->fsuid = new->euid = kuid; 792 793 retval = security_task_fix_setuid(new, old, LSM_SETID_ID); 794 if (retval < 0) 795 goto error; 796 797 return commit_creds(new); 798 799 error: 800 abort_creds(new); 801 return retval; 802 } 803 804 805 /* 806 * This function implements a generic ability to update ruid, euid, 807 * and suid. This allows you to implement the 4.4 compatible seteuid(). 808 */ 809 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid) 810 { 811 struct user_namespace *ns = current_user_ns(); 812 const struct cred *old; 813 struct cred *new; 814 int retval; 815 kuid_t kruid, keuid, ksuid; 816 817 kruid = make_kuid(ns, ruid); 818 keuid = make_kuid(ns, euid); 819 ksuid = make_kuid(ns, suid); 820 821 if ((ruid != (uid_t) -1) && !uid_valid(kruid)) 822 return -EINVAL; 823 824 if ((euid != (uid_t) -1) && !uid_valid(keuid)) 825 return -EINVAL; 826 827 if ((suid != (uid_t) -1) && !uid_valid(ksuid)) 828 return -EINVAL; 829 830 new = prepare_creds(); 831 if (!new) 832 return -ENOMEM; 833 834 old = current_cred(); 835 836 retval = -EPERM; 837 if (!nsown_capable(CAP_SETUID)) { 838 if (ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) && 839 !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid)) 840 goto error; 841 if (euid != (uid_t) -1 && !uid_eq(keuid, old->uid) && 842 !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid)) 843 goto error; 844 if (suid != (uid_t) -1 && !uid_eq(ksuid, old->uid) && 845 !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid)) 846 goto error; 847 } 848 849 if (ruid != (uid_t) -1) { 850 new->uid = kruid; 851 if (!uid_eq(kruid, old->uid)) { 852 retval = set_user(new); 853 if (retval < 0) 854 goto error; 855 } 856 } 857 if (euid != (uid_t) -1) 858 new->euid = keuid; 859 if (suid != (uid_t) -1) 860 new->suid = ksuid; 861 new->fsuid = new->euid; 862 863 retval = security_task_fix_setuid(new, old, LSM_SETID_RES); 864 if (retval < 0) 865 goto error; 866 867 return commit_creds(new); 868 869 error: 870 abort_creds(new); 871 return retval; 872 } 873 874 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp) 875 { 876 const struct cred *cred = current_cred(); 877 int retval; 878 uid_t ruid, euid, suid; 879 880 ruid = from_kuid_munged(cred->user_ns, cred->uid); 881 euid = from_kuid_munged(cred->user_ns, cred->euid); 882 suid = from_kuid_munged(cred->user_ns, cred->suid); 883 884 if (!(retval = put_user(ruid, ruidp)) && 885 !(retval = put_user(euid, euidp))) 886 retval = put_user(suid, suidp); 887 888 return retval; 889 } 890 891 /* 892 * Same as above, but for rgid, egid, sgid. 893 */ 894 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid) 895 { 896 struct user_namespace *ns = current_user_ns(); 897 const struct cred *old; 898 struct cred *new; 899 int retval; 900 kgid_t krgid, kegid, ksgid; 901 902 krgid = make_kgid(ns, rgid); 903 kegid = make_kgid(ns, egid); 904 ksgid = make_kgid(ns, sgid); 905 906 if ((rgid != (gid_t) -1) && !gid_valid(krgid)) 907 return -EINVAL; 908 if ((egid != (gid_t) -1) && !gid_valid(kegid)) 909 return -EINVAL; 910 if ((sgid != (gid_t) -1) && !gid_valid(ksgid)) 911 return -EINVAL; 912 913 new = prepare_creds(); 914 if (!new) 915 return -ENOMEM; 916 old = current_cred(); 917 918 retval = -EPERM; 919 if (!nsown_capable(CAP_SETGID)) { 920 if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) && 921 !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid)) 922 goto error; 923 if (egid != (gid_t) -1 && !gid_eq(kegid, old->gid) && 924 !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid)) 925 goto error; 926 if (sgid != (gid_t) -1 && !gid_eq(ksgid, old->gid) && 927 !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid)) 928 goto error; 929 } 930 931 if (rgid != (gid_t) -1) 932 new->gid = krgid; 933 if (egid != (gid_t) -1) 934 new->egid = kegid; 935 if (sgid != (gid_t) -1) 936 new->sgid = ksgid; 937 new->fsgid = new->egid; 938 939 return commit_creds(new); 940 941 error: 942 abort_creds(new); 943 return retval; 944 } 945 946 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp) 947 { 948 const struct cred *cred = current_cred(); 949 int retval; 950 gid_t rgid, egid, sgid; 951 952 rgid = from_kgid_munged(cred->user_ns, cred->gid); 953 egid = from_kgid_munged(cred->user_ns, cred->egid); 954 sgid = from_kgid_munged(cred->user_ns, cred->sgid); 955 956 if (!(retval = put_user(rgid, rgidp)) && 957 !(retval = put_user(egid, egidp))) 958 retval = put_user(sgid, sgidp); 959 960 return retval; 961 } 962 963 964 /* 965 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This 966 * is used for "access()" and for the NFS daemon (letting nfsd stay at 967 * whatever uid it wants to). It normally shadows "euid", except when 968 * explicitly set by setfsuid() or for access.. 969 */ 970 SYSCALL_DEFINE1(setfsuid, uid_t, uid) 971 { 972 const struct cred *old; 973 struct cred *new; 974 uid_t old_fsuid; 975 kuid_t kuid; 976 977 old = current_cred(); 978 old_fsuid = from_kuid_munged(old->user_ns, old->fsuid); 979 980 kuid = make_kuid(old->user_ns, uid); 981 if (!uid_valid(kuid)) 982 return old_fsuid; 983 984 new = prepare_creds(); 985 if (!new) 986 return old_fsuid; 987 988 if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) || 989 uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) || 990 nsown_capable(CAP_SETUID)) { 991 if (!uid_eq(kuid, old->fsuid)) { 992 new->fsuid = kuid; 993 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0) 994 goto change_okay; 995 } 996 } 997 998 abort_creds(new); 999 return old_fsuid; 1000 1001 change_okay: 1002 commit_creds(new); 1003 return old_fsuid; 1004 } 1005 1006 /* 1007 * Samma på svenska.. 1008 */ 1009 SYSCALL_DEFINE1(setfsgid, gid_t, gid) 1010 { 1011 const struct cred *old; 1012 struct cred *new; 1013 gid_t old_fsgid; 1014 kgid_t kgid; 1015 1016 old = current_cred(); 1017 old_fsgid = from_kgid_munged(old->user_ns, old->fsgid); 1018 1019 kgid = make_kgid(old->user_ns, gid); 1020 if (!gid_valid(kgid)) 1021 return old_fsgid; 1022 1023 new = prepare_creds(); 1024 if (!new) 1025 return old_fsgid; 1026 1027 if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) || 1028 gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) || 1029 nsown_capable(CAP_SETGID)) { 1030 if (!gid_eq(kgid, old->fsgid)) { 1031 new->fsgid = kgid; 1032 goto change_okay; 1033 } 1034 } 1035 1036 abort_creds(new); 1037 return old_fsgid; 1038 1039 change_okay: 1040 commit_creds(new); 1041 return old_fsgid; 1042 } 1043 1044 void do_sys_times(struct tms *tms) 1045 { 1046 cputime_t tgutime, tgstime, cutime, cstime; 1047 1048 spin_lock_irq(¤t->sighand->siglock); 1049 thread_group_times(current, &tgutime, &tgstime); 1050 cutime = current->signal->cutime; 1051 cstime = current->signal->cstime; 1052 spin_unlock_irq(¤t->sighand->siglock); 1053 tms->tms_utime = cputime_to_clock_t(tgutime); 1054 tms->tms_stime = cputime_to_clock_t(tgstime); 1055 tms->tms_cutime = cputime_to_clock_t(cutime); 1056 tms->tms_cstime = cputime_to_clock_t(cstime); 1057 } 1058 1059 SYSCALL_DEFINE1(times, struct tms __user *, tbuf) 1060 { 1061 if (tbuf) { 1062 struct tms tmp; 1063 1064 do_sys_times(&tmp); 1065 if (copy_to_user(tbuf, &tmp, sizeof(struct tms))) 1066 return -EFAULT; 1067 } 1068 force_successful_syscall_return(); 1069 return (long) jiffies_64_to_clock_t(get_jiffies_64()); 1070 } 1071 1072 /* 1073 * This needs some heavy checking ... 1074 * I just haven't the stomach for it. I also don't fully 1075 * understand sessions/pgrp etc. Let somebody who does explain it. 1076 * 1077 * OK, I think I have the protection semantics right.... this is really 1078 * only important on a multi-user system anyway, to make sure one user 1079 * can't send a signal to a process owned by another. -TYT, 12/12/91 1080 * 1081 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX. 1082 * LBT 04.03.94 1083 */ 1084 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid) 1085 { 1086 struct task_struct *p; 1087 struct task_struct *group_leader = current->group_leader; 1088 struct pid *pgrp; 1089 int err; 1090 1091 if (!pid) 1092 pid = task_pid_vnr(group_leader); 1093 if (!pgid) 1094 pgid = pid; 1095 if (pgid < 0) 1096 return -EINVAL; 1097 rcu_read_lock(); 1098 1099 /* From this point forward we keep holding onto the tasklist lock 1100 * so that our parent does not change from under us. -DaveM 1101 */ 1102 write_lock_irq(&tasklist_lock); 1103 1104 err = -ESRCH; 1105 p = find_task_by_vpid(pid); 1106 if (!p) 1107 goto out; 1108 1109 err = -EINVAL; 1110 if (!thread_group_leader(p)) 1111 goto out; 1112 1113 if (same_thread_group(p->real_parent, group_leader)) { 1114 err = -EPERM; 1115 if (task_session(p) != task_session(group_leader)) 1116 goto out; 1117 err = -EACCES; 1118 if (p->did_exec) 1119 goto out; 1120 } else { 1121 err = -ESRCH; 1122 if (p != group_leader) 1123 goto out; 1124 } 1125 1126 err = -EPERM; 1127 if (p->signal->leader) 1128 goto out; 1129 1130 pgrp = task_pid(p); 1131 if (pgid != pid) { 1132 struct task_struct *g; 1133 1134 pgrp = find_vpid(pgid); 1135 g = pid_task(pgrp, PIDTYPE_PGID); 1136 if (!g || task_session(g) != task_session(group_leader)) 1137 goto out; 1138 } 1139 1140 err = security_task_setpgid(p, pgid); 1141 if (err) 1142 goto out; 1143 1144 if (task_pgrp(p) != pgrp) 1145 change_pid(p, PIDTYPE_PGID, pgrp); 1146 1147 err = 0; 1148 out: 1149 /* All paths lead to here, thus we are safe. -DaveM */ 1150 write_unlock_irq(&tasklist_lock); 1151 rcu_read_unlock(); 1152 return err; 1153 } 1154 1155 SYSCALL_DEFINE1(getpgid, pid_t, pid) 1156 { 1157 struct task_struct *p; 1158 struct pid *grp; 1159 int retval; 1160 1161 rcu_read_lock(); 1162 if (!pid) 1163 grp = task_pgrp(current); 1164 else { 1165 retval = -ESRCH; 1166 p = find_task_by_vpid(pid); 1167 if (!p) 1168 goto out; 1169 grp = task_pgrp(p); 1170 if (!grp) 1171 goto out; 1172 1173 retval = security_task_getpgid(p); 1174 if (retval) 1175 goto out; 1176 } 1177 retval = pid_vnr(grp); 1178 out: 1179 rcu_read_unlock(); 1180 return retval; 1181 } 1182 1183 #ifdef __ARCH_WANT_SYS_GETPGRP 1184 1185 SYSCALL_DEFINE0(getpgrp) 1186 { 1187 return sys_getpgid(0); 1188 } 1189 1190 #endif 1191 1192 SYSCALL_DEFINE1(getsid, pid_t, pid) 1193 { 1194 struct task_struct *p; 1195 struct pid *sid; 1196 int retval; 1197 1198 rcu_read_lock(); 1199 if (!pid) 1200 sid = task_session(current); 1201 else { 1202 retval = -ESRCH; 1203 p = find_task_by_vpid(pid); 1204 if (!p) 1205 goto out; 1206 sid = task_session(p); 1207 if (!sid) 1208 goto out; 1209 1210 retval = security_task_getsid(p); 1211 if (retval) 1212 goto out; 1213 } 1214 retval = pid_vnr(sid); 1215 out: 1216 rcu_read_unlock(); 1217 return retval; 1218 } 1219 1220 SYSCALL_DEFINE0(setsid) 1221 { 1222 struct task_struct *group_leader = current->group_leader; 1223 struct pid *sid = task_pid(group_leader); 1224 pid_t session = pid_vnr(sid); 1225 int err = -EPERM; 1226 1227 write_lock_irq(&tasklist_lock); 1228 /* Fail if I am already a session leader */ 1229 if (group_leader->signal->leader) 1230 goto out; 1231 1232 /* Fail if a process group id already exists that equals the 1233 * proposed session id. 1234 */ 1235 if (pid_task(sid, PIDTYPE_PGID)) 1236 goto out; 1237 1238 group_leader->signal->leader = 1; 1239 __set_special_pids(sid); 1240 1241 proc_clear_tty(group_leader); 1242 1243 err = session; 1244 out: 1245 write_unlock_irq(&tasklist_lock); 1246 if (err > 0) { 1247 proc_sid_connector(group_leader); 1248 sched_autogroup_create_attach(group_leader); 1249 } 1250 return err; 1251 } 1252 1253 DECLARE_RWSEM(uts_sem); 1254 1255 #ifdef COMPAT_UTS_MACHINE 1256 #define override_architecture(name) \ 1257 (personality(current->personality) == PER_LINUX32 && \ 1258 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \ 1259 sizeof(COMPAT_UTS_MACHINE))) 1260 #else 1261 #define override_architecture(name) 0 1262 #endif 1263 1264 /* 1265 * Work around broken programs that cannot handle "Linux 3.0". 1266 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40 1267 */ 1268 static int override_release(char __user *release, size_t len) 1269 { 1270 int ret = 0; 1271 1272 if (current->personality & UNAME26) { 1273 const char *rest = UTS_RELEASE; 1274 char buf[65] = { 0 }; 1275 int ndots = 0; 1276 unsigned v; 1277 size_t copy; 1278 1279 while (*rest) { 1280 if (*rest == '.' && ++ndots >= 3) 1281 break; 1282 if (!isdigit(*rest) && *rest != '.') 1283 break; 1284 rest++; 1285 } 1286 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40; 1287 copy = clamp_t(size_t, len, 1, sizeof(buf)); 1288 copy = scnprintf(buf, copy, "2.6.%u%s", v, rest); 1289 ret = copy_to_user(release, buf, copy + 1); 1290 } 1291 return ret; 1292 } 1293 1294 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name) 1295 { 1296 int errno = 0; 1297 1298 down_read(&uts_sem); 1299 if (copy_to_user(name, utsname(), sizeof *name)) 1300 errno = -EFAULT; 1301 up_read(&uts_sem); 1302 1303 if (!errno && override_release(name->release, sizeof(name->release))) 1304 errno = -EFAULT; 1305 if (!errno && override_architecture(name)) 1306 errno = -EFAULT; 1307 return errno; 1308 } 1309 1310 #ifdef __ARCH_WANT_SYS_OLD_UNAME 1311 /* 1312 * Old cruft 1313 */ 1314 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name) 1315 { 1316 int error = 0; 1317 1318 if (!name) 1319 return -EFAULT; 1320 1321 down_read(&uts_sem); 1322 if (copy_to_user(name, utsname(), sizeof(*name))) 1323 error = -EFAULT; 1324 up_read(&uts_sem); 1325 1326 if (!error && override_release(name->release, sizeof(name->release))) 1327 error = -EFAULT; 1328 if (!error && override_architecture(name)) 1329 error = -EFAULT; 1330 return error; 1331 } 1332 1333 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name) 1334 { 1335 int error; 1336 1337 if (!name) 1338 return -EFAULT; 1339 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname))) 1340 return -EFAULT; 1341 1342 down_read(&uts_sem); 1343 error = __copy_to_user(&name->sysname, &utsname()->sysname, 1344 __OLD_UTS_LEN); 1345 error |= __put_user(0, name->sysname + __OLD_UTS_LEN); 1346 error |= __copy_to_user(&name->nodename, &utsname()->nodename, 1347 __OLD_UTS_LEN); 1348 error |= __put_user(0, name->nodename + __OLD_UTS_LEN); 1349 error |= __copy_to_user(&name->release, &utsname()->release, 1350 __OLD_UTS_LEN); 1351 error |= __put_user(0, name->release + __OLD_UTS_LEN); 1352 error |= __copy_to_user(&name->version, &utsname()->version, 1353 __OLD_UTS_LEN); 1354 error |= __put_user(0, name->version + __OLD_UTS_LEN); 1355 error |= __copy_to_user(&name->machine, &utsname()->machine, 1356 __OLD_UTS_LEN); 1357 error |= __put_user(0, name->machine + __OLD_UTS_LEN); 1358 up_read(&uts_sem); 1359 1360 if (!error && override_architecture(name)) 1361 error = -EFAULT; 1362 if (!error && override_release(name->release, sizeof(name->release))) 1363 error = -EFAULT; 1364 return error ? -EFAULT : 0; 1365 } 1366 #endif 1367 1368 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len) 1369 { 1370 int errno; 1371 char tmp[__NEW_UTS_LEN]; 1372 1373 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN)) 1374 return -EPERM; 1375 1376 if (len < 0 || len > __NEW_UTS_LEN) 1377 return -EINVAL; 1378 down_write(&uts_sem); 1379 errno = -EFAULT; 1380 if (!copy_from_user(tmp, name, len)) { 1381 struct new_utsname *u = utsname(); 1382 1383 memcpy(u->nodename, tmp, len); 1384 memset(u->nodename + len, 0, sizeof(u->nodename) - len); 1385 errno = 0; 1386 uts_proc_notify(UTS_PROC_HOSTNAME); 1387 } 1388 up_write(&uts_sem); 1389 return errno; 1390 } 1391 1392 #ifdef __ARCH_WANT_SYS_GETHOSTNAME 1393 1394 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len) 1395 { 1396 int i, errno; 1397 struct new_utsname *u; 1398 1399 if (len < 0) 1400 return -EINVAL; 1401 down_read(&uts_sem); 1402 u = utsname(); 1403 i = 1 + strlen(u->nodename); 1404 if (i > len) 1405 i = len; 1406 errno = 0; 1407 if (copy_to_user(name, u->nodename, i)) 1408 errno = -EFAULT; 1409 up_read(&uts_sem); 1410 return errno; 1411 } 1412 1413 #endif 1414 1415 /* 1416 * Only setdomainname; getdomainname can be implemented by calling 1417 * uname() 1418 */ 1419 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len) 1420 { 1421 int errno; 1422 char tmp[__NEW_UTS_LEN]; 1423 1424 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN)) 1425 return -EPERM; 1426 if (len < 0 || len > __NEW_UTS_LEN) 1427 return -EINVAL; 1428 1429 down_write(&uts_sem); 1430 errno = -EFAULT; 1431 if (!copy_from_user(tmp, name, len)) { 1432 struct new_utsname *u = utsname(); 1433 1434 memcpy(u->domainname, tmp, len); 1435 memset(u->domainname + len, 0, sizeof(u->domainname) - len); 1436 errno = 0; 1437 uts_proc_notify(UTS_PROC_DOMAINNAME); 1438 } 1439 up_write(&uts_sem); 1440 return errno; 1441 } 1442 1443 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim) 1444 { 1445 struct rlimit value; 1446 int ret; 1447 1448 ret = do_prlimit(current, resource, NULL, &value); 1449 if (!ret) 1450 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0; 1451 1452 return ret; 1453 } 1454 1455 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT 1456 1457 /* 1458 * Back compatibility for getrlimit. Needed for some apps. 1459 */ 1460 1461 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource, 1462 struct rlimit __user *, rlim) 1463 { 1464 struct rlimit x; 1465 if (resource >= RLIM_NLIMITS) 1466 return -EINVAL; 1467 1468 task_lock(current->group_leader); 1469 x = current->signal->rlim[resource]; 1470 task_unlock(current->group_leader); 1471 if (x.rlim_cur > 0x7FFFFFFF) 1472 x.rlim_cur = 0x7FFFFFFF; 1473 if (x.rlim_max > 0x7FFFFFFF) 1474 x.rlim_max = 0x7FFFFFFF; 1475 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0; 1476 } 1477 1478 #endif 1479 1480 static inline bool rlim64_is_infinity(__u64 rlim64) 1481 { 1482 #if BITS_PER_LONG < 64 1483 return rlim64 >= ULONG_MAX; 1484 #else 1485 return rlim64 == RLIM64_INFINITY; 1486 #endif 1487 } 1488 1489 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64) 1490 { 1491 if (rlim->rlim_cur == RLIM_INFINITY) 1492 rlim64->rlim_cur = RLIM64_INFINITY; 1493 else 1494 rlim64->rlim_cur = rlim->rlim_cur; 1495 if (rlim->rlim_max == RLIM_INFINITY) 1496 rlim64->rlim_max = RLIM64_INFINITY; 1497 else 1498 rlim64->rlim_max = rlim->rlim_max; 1499 } 1500 1501 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim) 1502 { 1503 if (rlim64_is_infinity(rlim64->rlim_cur)) 1504 rlim->rlim_cur = RLIM_INFINITY; 1505 else 1506 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur; 1507 if (rlim64_is_infinity(rlim64->rlim_max)) 1508 rlim->rlim_max = RLIM_INFINITY; 1509 else 1510 rlim->rlim_max = (unsigned long)rlim64->rlim_max; 1511 } 1512 1513 /* make sure you are allowed to change @tsk limits before calling this */ 1514 int do_prlimit(struct task_struct *tsk, unsigned int resource, 1515 struct rlimit *new_rlim, struct rlimit *old_rlim) 1516 { 1517 struct rlimit *rlim; 1518 int retval = 0; 1519 1520 if (resource >= RLIM_NLIMITS) 1521 return -EINVAL; 1522 if (new_rlim) { 1523 if (new_rlim->rlim_cur > new_rlim->rlim_max) 1524 return -EINVAL; 1525 if (resource == RLIMIT_NOFILE && 1526 new_rlim->rlim_max > sysctl_nr_open) 1527 return -EPERM; 1528 } 1529 1530 /* protect tsk->signal and tsk->sighand from disappearing */ 1531 read_lock(&tasklist_lock); 1532 if (!tsk->sighand) { 1533 retval = -ESRCH; 1534 goto out; 1535 } 1536 1537 rlim = tsk->signal->rlim + resource; 1538 task_lock(tsk->group_leader); 1539 if (new_rlim) { 1540 /* Keep the capable check against init_user_ns until 1541 cgroups can contain all limits */ 1542 if (new_rlim->rlim_max > rlim->rlim_max && 1543 !capable(CAP_SYS_RESOURCE)) 1544 retval = -EPERM; 1545 if (!retval) 1546 retval = security_task_setrlimit(tsk->group_leader, 1547 resource, new_rlim); 1548 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) { 1549 /* 1550 * The caller is asking for an immediate RLIMIT_CPU 1551 * expiry. But we use the zero value to mean "it was 1552 * never set". So let's cheat and make it one second 1553 * instead 1554 */ 1555 new_rlim->rlim_cur = 1; 1556 } 1557 } 1558 if (!retval) { 1559 if (old_rlim) 1560 *old_rlim = *rlim; 1561 if (new_rlim) 1562 *rlim = *new_rlim; 1563 } 1564 task_unlock(tsk->group_leader); 1565 1566 /* 1567 * RLIMIT_CPU handling. Note that the kernel fails to return an error 1568 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a 1569 * very long-standing error, and fixing it now risks breakage of 1570 * applications, so we live with it 1571 */ 1572 if (!retval && new_rlim && resource == RLIMIT_CPU && 1573 new_rlim->rlim_cur != RLIM_INFINITY) 1574 update_rlimit_cpu(tsk, new_rlim->rlim_cur); 1575 out: 1576 read_unlock(&tasklist_lock); 1577 return retval; 1578 } 1579 1580 /* rcu lock must be held */ 1581 static int check_prlimit_permission(struct task_struct *task) 1582 { 1583 const struct cred *cred = current_cred(), *tcred; 1584 1585 if (current == task) 1586 return 0; 1587 1588 tcred = __task_cred(task); 1589 if (uid_eq(cred->uid, tcred->euid) && 1590 uid_eq(cred->uid, tcred->suid) && 1591 uid_eq(cred->uid, tcred->uid) && 1592 gid_eq(cred->gid, tcred->egid) && 1593 gid_eq(cred->gid, tcred->sgid) && 1594 gid_eq(cred->gid, tcred->gid)) 1595 return 0; 1596 if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE)) 1597 return 0; 1598 1599 return -EPERM; 1600 } 1601 1602 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource, 1603 const struct rlimit64 __user *, new_rlim, 1604 struct rlimit64 __user *, old_rlim) 1605 { 1606 struct rlimit64 old64, new64; 1607 struct rlimit old, new; 1608 struct task_struct *tsk; 1609 int ret; 1610 1611 if (new_rlim) { 1612 if (copy_from_user(&new64, new_rlim, sizeof(new64))) 1613 return -EFAULT; 1614 rlim64_to_rlim(&new64, &new); 1615 } 1616 1617 rcu_read_lock(); 1618 tsk = pid ? find_task_by_vpid(pid) : current; 1619 if (!tsk) { 1620 rcu_read_unlock(); 1621 return -ESRCH; 1622 } 1623 ret = check_prlimit_permission(tsk); 1624 if (ret) { 1625 rcu_read_unlock(); 1626 return ret; 1627 } 1628 get_task_struct(tsk); 1629 rcu_read_unlock(); 1630 1631 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL, 1632 old_rlim ? &old : NULL); 1633 1634 if (!ret && old_rlim) { 1635 rlim_to_rlim64(&old, &old64); 1636 if (copy_to_user(old_rlim, &old64, sizeof(old64))) 1637 ret = -EFAULT; 1638 } 1639 1640 put_task_struct(tsk); 1641 return ret; 1642 } 1643 1644 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim) 1645 { 1646 struct rlimit new_rlim; 1647 1648 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim))) 1649 return -EFAULT; 1650 return do_prlimit(current, resource, &new_rlim, NULL); 1651 } 1652 1653 /* 1654 * It would make sense to put struct rusage in the task_struct, 1655 * except that would make the task_struct be *really big*. After 1656 * task_struct gets moved into malloc'ed memory, it would 1657 * make sense to do this. It will make moving the rest of the information 1658 * a lot simpler! (Which we're not doing right now because we're not 1659 * measuring them yet). 1660 * 1661 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have 1662 * races with threads incrementing their own counters. But since word 1663 * reads are atomic, we either get new values or old values and we don't 1664 * care which for the sums. We always take the siglock to protect reading 1665 * the c* fields from p->signal from races with exit.c updating those 1666 * fields when reaping, so a sample either gets all the additions of a 1667 * given child after it's reaped, or none so this sample is before reaping. 1668 * 1669 * Locking: 1670 * We need to take the siglock for CHILDEREN, SELF and BOTH 1671 * for the cases current multithreaded, non-current single threaded 1672 * non-current multithreaded. Thread traversal is now safe with 1673 * the siglock held. 1674 * Strictly speaking, we donot need to take the siglock if we are current and 1675 * single threaded, as no one else can take our signal_struct away, no one 1676 * else can reap the children to update signal->c* counters, and no one else 1677 * can race with the signal-> fields. If we do not take any lock, the 1678 * signal-> fields could be read out of order while another thread was just 1679 * exiting. So we should place a read memory barrier when we avoid the lock. 1680 * On the writer side, write memory barrier is implied in __exit_signal 1681 * as __exit_signal releases the siglock spinlock after updating the signal-> 1682 * fields. But we don't do this yet to keep things simple. 1683 * 1684 */ 1685 1686 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r) 1687 { 1688 r->ru_nvcsw += t->nvcsw; 1689 r->ru_nivcsw += t->nivcsw; 1690 r->ru_minflt += t->min_flt; 1691 r->ru_majflt += t->maj_flt; 1692 r->ru_inblock += task_io_get_inblock(t); 1693 r->ru_oublock += task_io_get_oublock(t); 1694 } 1695 1696 static void k_getrusage(struct task_struct *p, int who, struct rusage *r) 1697 { 1698 struct task_struct *t; 1699 unsigned long flags; 1700 cputime_t tgutime, tgstime, utime, stime; 1701 unsigned long maxrss = 0; 1702 1703 memset((char *) r, 0, sizeof *r); 1704 utime = stime = 0; 1705 1706 if (who == RUSAGE_THREAD) { 1707 task_times(current, &utime, &stime); 1708 accumulate_thread_rusage(p, r); 1709 maxrss = p->signal->maxrss; 1710 goto out; 1711 } 1712 1713 if (!lock_task_sighand(p, &flags)) 1714 return; 1715 1716 switch (who) { 1717 case RUSAGE_BOTH: 1718 case RUSAGE_CHILDREN: 1719 utime = p->signal->cutime; 1720 stime = p->signal->cstime; 1721 r->ru_nvcsw = p->signal->cnvcsw; 1722 r->ru_nivcsw = p->signal->cnivcsw; 1723 r->ru_minflt = p->signal->cmin_flt; 1724 r->ru_majflt = p->signal->cmaj_flt; 1725 r->ru_inblock = p->signal->cinblock; 1726 r->ru_oublock = p->signal->coublock; 1727 maxrss = p->signal->cmaxrss; 1728 1729 if (who == RUSAGE_CHILDREN) 1730 break; 1731 1732 case RUSAGE_SELF: 1733 thread_group_times(p, &tgutime, &tgstime); 1734 utime += tgutime; 1735 stime += tgstime; 1736 r->ru_nvcsw += p->signal->nvcsw; 1737 r->ru_nivcsw += p->signal->nivcsw; 1738 r->ru_minflt += p->signal->min_flt; 1739 r->ru_majflt += p->signal->maj_flt; 1740 r->ru_inblock += p->signal->inblock; 1741 r->ru_oublock += p->signal->oublock; 1742 if (maxrss < p->signal->maxrss) 1743 maxrss = p->signal->maxrss; 1744 t = p; 1745 do { 1746 accumulate_thread_rusage(t, r); 1747 t = next_thread(t); 1748 } while (t != p); 1749 break; 1750 1751 default: 1752 BUG(); 1753 } 1754 unlock_task_sighand(p, &flags); 1755 1756 out: 1757 cputime_to_timeval(utime, &r->ru_utime); 1758 cputime_to_timeval(stime, &r->ru_stime); 1759 1760 if (who != RUSAGE_CHILDREN) { 1761 struct mm_struct *mm = get_task_mm(p); 1762 if (mm) { 1763 setmax_mm_hiwater_rss(&maxrss, mm); 1764 mmput(mm); 1765 } 1766 } 1767 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */ 1768 } 1769 1770 int getrusage(struct task_struct *p, int who, struct rusage __user *ru) 1771 { 1772 struct rusage r; 1773 k_getrusage(p, who, &r); 1774 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0; 1775 } 1776 1777 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru) 1778 { 1779 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN && 1780 who != RUSAGE_THREAD) 1781 return -EINVAL; 1782 return getrusage(current, who, ru); 1783 } 1784 1785 SYSCALL_DEFINE1(umask, int, mask) 1786 { 1787 mask = xchg(¤t->fs->umask, mask & S_IRWXUGO); 1788 return mask; 1789 } 1790 1791 #ifdef CONFIG_CHECKPOINT_RESTORE 1792 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) 1793 { 1794 struct fd exe; 1795 struct dentry *dentry; 1796 int err; 1797 1798 exe = fdget(fd); 1799 if (!exe.file) 1800 return -EBADF; 1801 1802 dentry = exe.file->f_path.dentry; 1803 1804 /* 1805 * Because the original mm->exe_file points to executable file, make 1806 * sure that this one is executable as well, to avoid breaking an 1807 * overall picture. 1808 */ 1809 err = -EACCES; 1810 if (!S_ISREG(dentry->d_inode->i_mode) || 1811 exe.file->f_path.mnt->mnt_flags & MNT_NOEXEC) 1812 goto exit; 1813 1814 err = inode_permission(dentry->d_inode, MAY_EXEC); 1815 if (err) 1816 goto exit; 1817 1818 down_write(&mm->mmap_sem); 1819 1820 /* 1821 * Forbid mm->exe_file change if old file still mapped. 1822 */ 1823 err = -EBUSY; 1824 if (mm->exe_file) { 1825 struct vm_area_struct *vma; 1826 1827 for (vma = mm->mmap; vma; vma = vma->vm_next) 1828 if (vma->vm_file && 1829 path_equal(&vma->vm_file->f_path, 1830 &mm->exe_file->f_path)) 1831 goto exit_unlock; 1832 } 1833 1834 /* 1835 * The symlink can be changed only once, just to disallow arbitrary 1836 * transitions malicious software might bring in. This means one 1837 * could make a snapshot over all processes running and monitor 1838 * /proc/pid/exe changes to notice unusual activity if needed. 1839 */ 1840 err = -EPERM; 1841 if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags)) 1842 goto exit_unlock; 1843 1844 err = 0; 1845 set_mm_exe_file(mm, exe.file); /* this grabs a reference to exe.file */ 1846 exit_unlock: 1847 up_write(&mm->mmap_sem); 1848 1849 exit: 1850 fdput(exe); 1851 return err; 1852 } 1853 1854 static int prctl_set_mm(int opt, unsigned long addr, 1855 unsigned long arg4, unsigned long arg5) 1856 { 1857 unsigned long rlim = rlimit(RLIMIT_DATA); 1858 struct mm_struct *mm = current->mm; 1859 struct vm_area_struct *vma; 1860 int error; 1861 1862 if (arg5 || (arg4 && opt != PR_SET_MM_AUXV)) 1863 return -EINVAL; 1864 1865 if (!capable(CAP_SYS_RESOURCE)) 1866 return -EPERM; 1867 1868 if (opt == PR_SET_MM_EXE_FILE) 1869 return prctl_set_mm_exe_file(mm, (unsigned int)addr); 1870 1871 if (addr >= TASK_SIZE || addr < mmap_min_addr) 1872 return -EINVAL; 1873 1874 error = -EINVAL; 1875 1876 down_read(&mm->mmap_sem); 1877 vma = find_vma(mm, addr); 1878 1879 switch (opt) { 1880 case PR_SET_MM_START_CODE: 1881 mm->start_code = addr; 1882 break; 1883 case PR_SET_MM_END_CODE: 1884 mm->end_code = addr; 1885 break; 1886 case PR_SET_MM_START_DATA: 1887 mm->start_data = addr; 1888 break; 1889 case PR_SET_MM_END_DATA: 1890 mm->end_data = addr; 1891 break; 1892 1893 case PR_SET_MM_START_BRK: 1894 if (addr <= mm->end_data) 1895 goto out; 1896 1897 if (rlim < RLIM_INFINITY && 1898 (mm->brk - addr) + 1899 (mm->end_data - mm->start_data) > rlim) 1900 goto out; 1901 1902 mm->start_brk = addr; 1903 break; 1904 1905 case PR_SET_MM_BRK: 1906 if (addr <= mm->end_data) 1907 goto out; 1908 1909 if (rlim < RLIM_INFINITY && 1910 (addr - mm->start_brk) + 1911 (mm->end_data - mm->start_data) > rlim) 1912 goto out; 1913 1914 mm->brk = addr; 1915 break; 1916 1917 /* 1918 * If command line arguments and environment 1919 * are placed somewhere else on stack, we can 1920 * set them up here, ARG_START/END to setup 1921 * command line argumets and ENV_START/END 1922 * for environment. 1923 */ 1924 case PR_SET_MM_START_STACK: 1925 case PR_SET_MM_ARG_START: 1926 case PR_SET_MM_ARG_END: 1927 case PR_SET_MM_ENV_START: 1928 case PR_SET_MM_ENV_END: 1929 if (!vma) { 1930 error = -EFAULT; 1931 goto out; 1932 } 1933 if (opt == PR_SET_MM_START_STACK) 1934 mm->start_stack = addr; 1935 else if (opt == PR_SET_MM_ARG_START) 1936 mm->arg_start = addr; 1937 else if (opt == PR_SET_MM_ARG_END) 1938 mm->arg_end = addr; 1939 else if (opt == PR_SET_MM_ENV_START) 1940 mm->env_start = addr; 1941 else if (opt == PR_SET_MM_ENV_END) 1942 mm->env_end = addr; 1943 break; 1944 1945 /* 1946 * This doesn't move auxiliary vector itself 1947 * since it's pinned to mm_struct, but allow 1948 * to fill vector with new values. It's up 1949 * to a caller to provide sane values here 1950 * otherwise user space tools which use this 1951 * vector might be unhappy. 1952 */ 1953 case PR_SET_MM_AUXV: { 1954 unsigned long user_auxv[AT_VECTOR_SIZE]; 1955 1956 if (arg4 > sizeof(user_auxv)) 1957 goto out; 1958 up_read(&mm->mmap_sem); 1959 1960 if (copy_from_user(user_auxv, (const void __user *)addr, arg4)) 1961 return -EFAULT; 1962 1963 /* Make sure the last entry is always AT_NULL */ 1964 user_auxv[AT_VECTOR_SIZE - 2] = 0; 1965 user_auxv[AT_VECTOR_SIZE - 1] = 0; 1966 1967 BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv)); 1968 1969 task_lock(current); 1970 memcpy(mm->saved_auxv, user_auxv, arg4); 1971 task_unlock(current); 1972 1973 return 0; 1974 } 1975 default: 1976 goto out; 1977 } 1978 1979 error = 0; 1980 out: 1981 up_read(&mm->mmap_sem); 1982 return error; 1983 } 1984 1985 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr) 1986 { 1987 return put_user(me->clear_child_tid, tid_addr); 1988 } 1989 1990 #else /* CONFIG_CHECKPOINT_RESTORE */ 1991 static int prctl_set_mm(int opt, unsigned long addr, 1992 unsigned long arg4, unsigned long arg5) 1993 { 1994 return -EINVAL; 1995 } 1996 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr) 1997 { 1998 return -EINVAL; 1999 } 2000 #endif 2001 2002 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, 2003 unsigned long, arg4, unsigned long, arg5) 2004 { 2005 struct task_struct *me = current; 2006 unsigned char comm[sizeof(me->comm)]; 2007 long error; 2008 2009 error = security_task_prctl(option, arg2, arg3, arg4, arg5); 2010 if (error != -ENOSYS) 2011 return error; 2012 2013 error = 0; 2014 switch (option) { 2015 case PR_SET_PDEATHSIG: 2016 if (!valid_signal(arg2)) { 2017 error = -EINVAL; 2018 break; 2019 } 2020 me->pdeath_signal = arg2; 2021 break; 2022 case PR_GET_PDEATHSIG: 2023 error = put_user(me->pdeath_signal, (int __user *)arg2); 2024 break; 2025 case PR_GET_DUMPABLE: 2026 error = get_dumpable(me->mm); 2027 break; 2028 case PR_SET_DUMPABLE: 2029 if (arg2 < 0 || arg2 > 1) { 2030 error = -EINVAL; 2031 break; 2032 } 2033 set_dumpable(me->mm, arg2); 2034 break; 2035 2036 case PR_SET_UNALIGN: 2037 error = SET_UNALIGN_CTL(me, arg2); 2038 break; 2039 case PR_GET_UNALIGN: 2040 error = GET_UNALIGN_CTL(me, arg2); 2041 break; 2042 case PR_SET_FPEMU: 2043 error = SET_FPEMU_CTL(me, arg2); 2044 break; 2045 case PR_GET_FPEMU: 2046 error = GET_FPEMU_CTL(me, arg2); 2047 break; 2048 case PR_SET_FPEXC: 2049 error = SET_FPEXC_CTL(me, arg2); 2050 break; 2051 case PR_GET_FPEXC: 2052 error = GET_FPEXC_CTL(me, arg2); 2053 break; 2054 case PR_GET_TIMING: 2055 error = PR_TIMING_STATISTICAL; 2056 break; 2057 case PR_SET_TIMING: 2058 if (arg2 != PR_TIMING_STATISTICAL) 2059 error = -EINVAL; 2060 break; 2061 case PR_SET_NAME: 2062 comm[sizeof(me->comm)-1] = 0; 2063 if (strncpy_from_user(comm, (char __user *)arg2, 2064 sizeof(me->comm) - 1) < 0) 2065 return -EFAULT; 2066 set_task_comm(me, comm); 2067 proc_comm_connector(me); 2068 break; 2069 case PR_GET_NAME: 2070 get_task_comm(comm, me); 2071 if (copy_to_user((char __user *)arg2, comm, 2072 sizeof(comm))) 2073 return -EFAULT; 2074 break; 2075 case PR_GET_ENDIAN: 2076 error = GET_ENDIAN(me, arg2); 2077 break; 2078 case PR_SET_ENDIAN: 2079 error = SET_ENDIAN(me, arg2); 2080 break; 2081 case PR_GET_SECCOMP: 2082 error = prctl_get_seccomp(); 2083 break; 2084 case PR_SET_SECCOMP: 2085 error = prctl_set_seccomp(arg2, (char __user *)arg3); 2086 break; 2087 case PR_GET_TSC: 2088 error = GET_TSC_CTL(arg2); 2089 break; 2090 case PR_SET_TSC: 2091 error = SET_TSC_CTL(arg2); 2092 break; 2093 case PR_TASK_PERF_EVENTS_DISABLE: 2094 error = perf_event_task_disable(); 2095 break; 2096 case PR_TASK_PERF_EVENTS_ENABLE: 2097 error = perf_event_task_enable(); 2098 break; 2099 case PR_GET_TIMERSLACK: 2100 error = current->timer_slack_ns; 2101 break; 2102 case PR_SET_TIMERSLACK: 2103 if (arg2 <= 0) 2104 current->timer_slack_ns = 2105 current->default_timer_slack_ns; 2106 else 2107 current->timer_slack_ns = arg2; 2108 break; 2109 case PR_MCE_KILL: 2110 if (arg4 | arg5) 2111 return -EINVAL; 2112 switch (arg2) { 2113 case PR_MCE_KILL_CLEAR: 2114 if (arg3 != 0) 2115 return -EINVAL; 2116 current->flags &= ~PF_MCE_PROCESS; 2117 break; 2118 case PR_MCE_KILL_SET: 2119 current->flags |= PF_MCE_PROCESS; 2120 if (arg3 == PR_MCE_KILL_EARLY) 2121 current->flags |= PF_MCE_EARLY; 2122 else if (arg3 == PR_MCE_KILL_LATE) 2123 current->flags &= ~PF_MCE_EARLY; 2124 else if (arg3 == PR_MCE_KILL_DEFAULT) 2125 current->flags &= 2126 ~(PF_MCE_EARLY|PF_MCE_PROCESS); 2127 else 2128 return -EINVAL; 2129 break; 2130 default: 2131 return -EINVAL; 2132 } 2133 break; 2134 case PR_MCE_KILL_GET: 2135 if (arg2 | arg3 | arg4 | arg5) 2136 return -EINVAL; 2137 if (current->flags & PF_MCE_PROCESS) 2138 error = (current->flags & PF_MCE_EARLY) ? 2139 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE; 2140 else 2141 error = PR_MCE_KILL_DEFAULT; 2142 break; 2143 case PR_SET_MM: 2144 error = prctl_set_mm(arg2, arg3, arg4, arg5); 2145 break; 2146 case PR_GET_TID_ADDRESS: 2147 error = prctl_get_tid_address(me, (int __user **)arg2); 2148 break; 2149 case PR_SET_CHILD_SUBREAPER: 2150 me->signal->is_child_subreaper = !!arg2; 2151 break; 2152 case PR_GET_CHILD_SUBREAPER: 2153 error = put_user(me->signal->is_child_subreaper, 2154 (int __user *) arg2); 2155 break; 2156 case PR_SET_NO_NEW_PRIVS: 2157 if (arg2 != 1 || arg3 || arg4 || arg5) 2158 return -EINVAL; 2159 2160 current->no_new_privs = 1; 2161 break; 2162 case PR_GET_NO_NEW_PRIVS: 2163 if (arg2 || arg3 || arg4 || arg5) 2164 return -EINVAL; 2165 return current->no_new_privs ? 1 : 0; 2166 default: 2167 error = -EINVAL; 2168 break; 2169 } 2170 return error; 2171 } 2172 2173 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep, 2174 struct getcpu_cache __user *, unused) 2175 { 2176 int err = 0; 2177 int cpu = raw_smp_processor_id(); 2178 if (cpup) 2179 err |= put_user(cpu, cpup); 2180 if (nodep) 2181 err |= put_user(cpu_to_node(cpu), nodep); 2182 return err ? -EFAULT : 0; 2183 } 2184 2185 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; 2186 2187 static void argv_cleanup(struct subprocess_info *info) 2188 { 2189 argv_free(info->argv); 2190 } 2191 2192 static int __orderly_poweroff(void) 2193 { 2194 int argc; 2195 char **argv; 2196 static char *envp[] = { 2197 "HOME=/", 2198 "PATH=/sbin:/bin:/usr/sbin:/usr/bin", 2199 NULL 2200 }; 2201 int ret; 2202 2203 argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc); 2204 if (argv == NULL) { 2205 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n", 2206 __func__, poweroff_cmd); 2207 return -ENOMEM; 2208 } 2209 2210 ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_WAIT_EXEC, 2211 NULL, argv_cleanup, NULL); 2212 if (ret == -ENOMEM) 2213 argv_free(argv); 2214 2215 return ret; 2216 } 2217 2218 /** 2219 * orderly_poweroff - Trigger an orderly system poweroff 2220 * @force: force poweroff if command execution fails 2221 * 2222 * This may be called from any context to trigger a system shutdown. 2223 * If the orderly shutdown fails, it will force an immediate shutdown. 2224 */ 2225 int orderly_poweroff(bool force) 2226 { 2227 int ret = __orderly_poweroff(); 2228 2229 if (ret && force) { 2230 printk(KERN_WARNING "Failed to start orderly shutdown: " 2231 "forcing the issue\n"); 2232 2233 /* 2234 * I guess this should try to kick off some daemon to sync and 2235 * poweroff asap. Or not even bother syncing if we're doing an 2236 * emergency shutdown? 2237 */ 2238 emergency_sync(); 2239 kernel_power_off(); 2240 } 2241 2242 return ret; 2243 } 2244 EXPORT_SYMBOL_GPL(orderly_poweroff); 2245