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/gfp.h> 40 #include <linux/syscore_ops.h> 41 #include <linux/version.h> 42 #include <linux/ctype.h> 43 44 #include <linux/compat.h> 45 #include <linux/syscalls.h> 46 #include <linux/kprobes.h> 47 #include <linux/user_namespace.h> 48 49 #include <linux/kmsg_dump.h> 50 /* Move somewhere else to avoid recompiling? */ 51 #include <generated/utsrelease.h> 52 53 #include <asm/uaccess.h> 54 #include <asm/io.h> 55 #include <asm/unistd.h> 56 57 #ifndef SET_UNALIGN_CTL 58 # define SET_UNALIGN_CTL(a,b) (-EINVAL) 59 #endif 60 #ifndef GET_UNALIGN_CTL 61 # define GET_UNALIGN_CTL(a,b) (-EINVAL) 62 #endif 63 #ifndef SET_FPEMU_CTL 64 # define SET_FPEMU_CTL(a,b) (-EINVAL) 65 #endif 66 #ifndef GET_FPEMU_CTL 67 # define GET_FPEMU_CTL(a,b) (-EINVAL) 68 #endif 69 #ifndef SET_FPEXC_CTL 70 # define SET_FPEXC_CTL(a,b) (-EINVAL) 71 #endif 72 #ifndef GET_FPEXC_CTL 73 # define GET_FPEXC_CTL(a,b) (-EINVAL) 74 #endif 75 #ifndef GET_ENDIAN 76 # define GET_ENDIAN(a,b) (-EINVAL) 77 #endif 78 #ifndef SET_ENDIAN 79 # define SET_ENDIAN(a,b) (-EINVAL) 80 #endif 81 #ifndef GET_TSC_CTL 82 # define GET_TSC_CTL(a) (-EINVAL) 83 #endif 84 #ifndef SET_TSC_CTL 85 # define SET_TSC_CTL(a) (-EINVAL) 86 #endif 87 88 /* 89 * this is where the system-wide overflow UID and GID are defined, for 90 * architectures that now have 32-bit UID/GID but didn't in the past 91 */ 92 93 int overflowuid = DEFAULT_OVERFLOWUID; 94 int overflowgid = DEFAULT_OVERFLOWGID; 95 96 #ifdef CONFIG_UID16 97 EXPORT_SYMBOL(overflowuid); 98 EXPORT_SYMBOL(overflowgid); 99 #endif 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 (pcred->user->user_ns == cred->user->user_ns && 137 (pcred->uid == cred->euid || 138 pcred->euid == cred->euid)) 139 return true; 140 if (ns_capable(pcred->user->user_ns, CAP_SYS_NICE)) 141 return true; 142 return false; 143 } 144 145 /* 146 * set the priority of a task 147 * - the caller must hold the RCU read lock 148 */ 149 static int set_one_prio(struct task_struct *p, int niceval, int error) 150 { 151 int no_nice; 152 153 if (!set_one_prio_perm(p)) { 154 error = -EPERM; 155 goto out; 156 } 157 if (niceval < task_nice(p) && !can_nice(p, niceval)) { 158 error = -EACCES; 159 goto out; 160 } 161 no_nice = security_task_setnice(p, niceval); 162 if (no_nice) { 163 error = no_nice; 164 goto out; 165 } 166 if (error == -ESRCH) 167 error = 0; 168 set_user_nice(p, niceval); 169 out: 170 return error; 171 } 172 173 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval) 174 { 175 struct task_struct *g, *p; 176 struct user_struct *user; 177 const struct cred *cred = current_cred(); 178 int error = -EINVAL; 179 struct pid *pgrp; 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 user = (struct user_struct *) cred->user; 213 if (!who) 214 who = cred->uid; 215 else if ((who != cred->uid) && 216 !(user = find_user(who))) 217 goto out_unlock; /* No processes for this user */ 218 219 do_each_thread(g, p) { 220 if (__task_cred(p)->uid == who) 221 error = set_one_prio(p, niceval, error); 222 } while_each_thread(g, p); 223 if (who != cred->uid) 224 free_uid(user); /* For find_user() */ 225 break; 226 } 227 out_unlock: 228 read_unlock(&tasklist_lock); 229 rcu_read_unlock(); 230 out: 231 return error; 232 } 233 234 /* 235 * Ugh. To avoid negative return values, "getpriority()" will 236 * not return the normal nice-value, but a negated value that 237 * has been offset by 20 (ie it returns 40..1 instead of -20..19) 238 * to stay compatible. 239 */ 240 SYSCALL_DEFINE2(getpriority, int, which, int, who) 241 { 242 struct task_struct *g, *p; 243 struct user_struct *user; 244 const struct cred *cred = current_cred(); 245 long niceval, retval = -ESRCH; 246 struct pid *pgrp; 247 248 if (which > PRIO_USER || which < PRIO_PROCESS) 249 return -EINVAL; 250 251 rcu_read_lock(); 252 read_lock(&tasklist_lock); 253 switch (which) { 254 case PRIO_PROCESS: 255 if (who) 256 p = find_task_by_vpid(who); 257 else 258 p = current; 259 if (p) { 260 niceval = 20 - task_nice(p); 261 if (niceval > retval) 262 retval = niceval; 263 } 264 break; 265 case PRIO_PGRP: 266 if (who) 267 pgrp = find_vpid(who); 268 else 269 pgrp = task_pgrp(current); 270 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { 271 niceval = 20 - task_nice(p); 272 if (niceval > retval) 273 retval = niceval; 274 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); 275 break; 276 case PRIO_USER: 277 user = (struct user_struct *) cred->user; 278 if (!who) 279 who = cred->uid; 280 else if ((who != cred->uid) && 281 !(user = find_user(who))) 282 goto out_unlock; /* No processes for this user */ 283 284 do_each_thread(g, p) { 285 if (__task_cred(p)->uid == who) { 286 niceval = 20 - task_nice(p); 287 if (niceval > retval) 288 retval = niceval; 289 } 290 } while_each_thread(g, p); 291 if (who != cred->uid) 292 free_uid(user); /* for find_user() */ 293 break; 294 } 295 out_unlock: 296 read_unlock(&tasklist_lock); 297 rcu_read_unlock(); 298 299 return retval; 300 } 301 302 /** 303 * emergency_restart - reboot the system 304 * 305 * Without shutting down any hardware or taking any locks 306 * reboot the system. This is called when we know we are in 307 * trouble so this is our best effort to reboot. This is 308 * safe to call in interrupt context. 309 */ 310 void emergency_restart(void) 311 { 312 kmsg_dump(KMSG_DUMP_EMERG); 313 machine_emergency_restart(); 314 } 315 EXPORT_SYMBOL_GPL(emergency_restart); 316 317 void kernel_restart_prepare(char *cmd) 318 { 319 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); 320 system_state = SYSTEM_RESTART; 321 usermodehelper_disable(); 322 device_shutdown(); 323 syscore_shutdown(); 324 } 325 326 /** 327 * register_reboot_notifier - Register function to be called at reboot time 328 * @nb: Info about notifier function to be called 329 * 330 * Registers a function with the list of functions 331 * to be called at reboot time. 332 * 333 * Currently always returns zero, as blocking_notifier_chain_register() 334 * always returns zero. 335 */ 336 int register_reboot_notifier(struct notifier_block *nb) 337 { 338 return blocking_notifier_chain_register(&reboot_notifier_list, nb); 339 } 340 EXPORT_SYMBOL(register_reboot_notifier); 341 342 /** 343 * unregister_reboot_notifier - Unregister previously registered reboot notifier 344 * @nb: Hook to be unregistered 345 * 346 * Unregisters a previously registered reboot 347 * notifier function. 348 * 349 * Returns zero on success, or %-ENOENT on failure. 350 */ 351 int unregister_reboot_notifier(struct notifier_block *nb) 352 { 353 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb); 354 } 355 EXPORT_SYMBOL(unregister_reboot_notifier); 356 357 /** 358 * kernel_restart - reboot the system 359 * @cmd: pointer to buffer containing command to execute for restart 360 * or %NULL 361 * 362 * Shutdown everything and perform a clean reboot. 363 * This is not safe to call in interrupt context. 364 */ 365 void kernel_restart(char *cmd) 366 { 367 kernel_restart_prepare(cmd); 368 if (!cmd) 369 printk(KERN_EMERG "Restarting system.\n"); 370 else 371 printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); 372 kmsg_dump(KMSG_DUMP_RESTART); 373 machine_restart(cmd); 374 } 375 EXPORT_SYMBOL_GPL(kernel_restart); 376 377 static void kernel_shutdown_prepare(enum system_states state) 378 { 379 blocking_notifier_call_chain(&reboot_notifier_list, 380 (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL); 381 system_state = state; 382 usermodehelper_disable(); 383 device_shutdown(); 384 } 385 /** 386 * kernel_halt - halt the system 387 * 388 * Shutdown everything and perform a clean system halt. 389 */ 390 void kernel_halt(void) 391 { 392 kernel_shutdown_prepare(SYSTEM_HALT); 393 syscore_shutdown(); 394 printk(KERN_EMERG "System halted.\n"); 395 kmsg_dump(KMSG_DUMP_HALT); 396 machine_halt(); 397 } 398 399 EXPORT_SYMBOL_GPL(kernel_halt); 400 401 /** 402 * kernel_power_off - power_off the system 403 * 404 * Shutdown everything and perform a clean system power_off. 405 */ 406 void kernel_power_off(void) 407 { 408 kernel_shutdown_prepare(SYSTEM_POWER_OFF); 409 if (pm_power_off_prepare) 410 pm_power_off_prepare(); 411 disable_nonboot_cpus(); 412 syscore_shutdown(); 413 printk(KERN_EMERG "Power down.\n"); 414 kmsg_dump(KMSG_DUMP_POWEROFF); 415 machine_power_off(); 416 } 417 EXPORT_SYMBOL_GPL(kernel_power_off); 418 419 static DEFINE_MUTEX(reboot_mutex); 420 421 /* 422 * Reboot system call: for obvious reasons only root may call it, 423 * and even root needs to set up some magic numbers in the registers 424 * so that some mistake won't make this reboot the whole machine. 425 * You can also set the meaning of the ctrl-alt-del-key here. 426 * 427 * reboot doesn't sync: do that yourself before calling this. 428 */ 429 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, 430 void __user *, arg) 431 { 432 char buffer[256]; 433 int ret = 0; 434 435 /* We only trust the superuser with rebooting the system. */ 436 if (!capable(CAP_SYS_BOOT)) 437 return -EPERM; 438 439 /* For safety, we require "magic" arguments. */ 440 if (magic1 != LINUX_REBOOT_MAGIC1 || 441 (magic2 != LINUX_REBOOT_MAGIC2 && 442 magic2 != LINUX_REBOOT_MAGIC2A && 443 magic2 != LINUX_REBOOT_MAGIC2B && 444 magic2 != LINUX_REBOOT_MAGIC2C)) 445 return -EINVAL; 446 447 /* Instead of trying to make the power_off code look like 448 * halt when pm_power_off is not set do it the easy way. 449 */ 450 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) 451 cmd = LINUX_REBOOT_CMD_HALT; 452 453 mutex_lock(&reboot_mutex); 454 switch (cmd) { 455 case LINUX_REBOOT_CMD_RESTART: 456 kernel_restart(NULL); 457 break; 458 459 case LINUX_REBOOT_CMD_CAD_ON: 460 C_A_D = 1; 461 break; 462 463 case LINUX_REBOOT_CMD_CAD_OFF: 464 C_A_D = 0; 465 break; 466 467 case LINUX_REBOOT_CMD_HALT: 468 kernel_halt(); 469 do_exit(0); 470 panic("cannot halt"); 471 472 case LINUX_REBOOT_CMD_POWER_OFF: 473 kernel_power_off(); 474 do_exit(0); 475 break; 476 477 case LINUX_REBOOT_CMD_RESTART2: 478 if (strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1) < 0) { 479 ret = -EFAULT; 480 break; 481 } 482 buffer[sizeof(buffer) - 1] = '\0'; 483 484 kernel_restart(buffer); 485 break; 486 487 #ifdef CONFIG_KEXEC 488 case LINUX_REBOOT_CMD_KEXEC: 489 ret = kernel_kexec(); 490 break; 491 #endif 492 493 #ifdef CONFIG_HIBERNATION 494 case LINUX_REBOOT_CMD_SW_SUSPEND: 495 ret = hibernate(); 496 break; 497 #endif 498 499 default: 500 ret = -EINVAL; 501 break; 502 } 503 mutex_unlock(&reboot_mutex); 504 return ret; 505 } 506 507 static void deferred_cad(struct work_struct *dummy) 508 { 509 kernel_restart(NULL); 510 } 511 512 /* 513 * This function gets called by ctrl-alt-del - ie the keyboard interrupt. 514 * As it's called within an interrupt, it may NOT sync: the only choice 515 * is whether to reboot at once, or just ignore the ctrl-alt-del. 516 */ 517 void ctrl_alt_del(void) 518 { 519 static DECLARE_WORK(cad_work, deferred_cad); 520 521 if (C_A_D) 522 schedule_work(&cad_work); 523 else 524 kill_cad_pid(SIGINT, 1); 525 } 526 527 /* 528 * Unprivileged users may change the real gid to the effective gid 529 * or vice versa. (BSD-style) 530 * 531 * If you set the real gid at all, or set the effective gid to a value not 532 * equal to the real gid, then the saved gid is set to the new effective gid. 533 * 534 * This makes it possible for a setgid program to completely drop its 535 * privileges, which is often a useful assertion to make when you are doing 536 * a security audit over a program. 537 * 538 * The general idea is that a program which uses just setregid() will be 539 * 100% compatible with BSD. A program which uses just setgid() will be 540 * 100% compatible with POSIX with saved IDs. 541 * 542 * SMP: There are not races, the GIDs are checked only by filesystem 543 * operations (as far as semantic preservation is concerned). 544 */ 545 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid) 546 { 547 const struct cred *old; 548 struct cred *new; 549 int retval; 550 551 new = prepare_creds(); 552 if (!new) 553 return -ENOMEM; 554 old = current_cred(); 555 556 retval = -EPERM; 557 if (rgid != (gid_t) -1) { 558 if (old->gid == rgid || 559 old->egid == rgid || 560 nsown_capable(CAP_SETGID)) 561 new->gid = rgid; 562 else 563 goto error; 564 } 565 if (egid != (gid_t) -1) { 566 if (old->gid == egid || 567 old->egid == egid || 568 old->sgid == egid || 569 nsown_capable(CAP_SETGID)) 570 new->egid = egid; 571 else 572 goto error; 573 } 574 575 if (rgid != (gid_t) -1 || 576 (egid != (gid_t) -1 && egid != old->gid)) 577 new->sgid = new->egid; 578 new->fsgid = new->egid; 579 580 return commit_creds(new); 581 582 error: 583 abort_creds(new); 584 return retval; 585 } 586 587 /* 588 * setgid() is implemented like SysV w/ SAVED_IDS 589 * 590 * SMP: Same implicit races as above. 591 */ 592 SYSCALL_DEFINE1(setgid, gid_t, gid) 593 { 594 const struct cred *old; 595 struct cred *new; 596 int retval; 597 598 new = prepare_creds(); 599 if (!new) 600 return -ENOMEM; 601 old = current_cred(); 602 603 retval = -EPERM; 604 if (nsown_capable(CAP_SETGID)) 605 new->gid = new->egid = new->sgid = new->fsgid = gid; 606 else if (gid == old->gid || gid == old->sgid) 607 new->egid = new->fsgid = gid; 608 else 609 goto error; 610 611 return commit_creds(new); 612 613 error: 614 abort_creds(new); 615 return retval; 616 } 617 618 /* 619 * change the user struct in a credentials set to match the new UID 620 */ 621 static int set_user(struct cred *new) 622 { 623 struct user_struct *new_user; 624 625 new_user = alloc_uid(current_user_ns(), new->uid); 626 if (!new_user) 627 return -EAGAIN; 628 629 /* 630 * We don't fail in case of NPROC limit excess here because too many 631 * poorly written programs don't check set*uid() return code, assuming 632 * it never fails if called by root. We may still enforce NPROC limit 633 * for programs doing set*uid()+execve() by harmlessly deferring the 634 * failure to the execve() stage. 635 */ 636 if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) && 637 new_user != INIT_USER) 638 current->flags |= PF_NPROC_EXCEEDED; 639 else 640 current->flags &= ~PF_NPROC_EXCEEDED; 641 642 free_uid(new->user); 643 new->user = new_user; 644 return 0; 645 } 646 647 /* 648 * Unprivileged users may change the real uid to the effective uid 649 * or vice versa. (BSD-style) 650 * 651 * If you set the real uid at all, or set the effective uid to a value not 652 * equal to the real uid, then the saved uid is set to the new effective uid. 653 * 654 * This makes it possible for a setuid program to completely drop its 655 * privileges, which is often a useful assertion to make when you are doing 656 * a security audit over a program. 657 * 658 * The general idea is that a program which uses just setreuid() will be 659 * 100% compatible with BSD. A program which uses just setuid() will be 660 * 100% compatible with POSIX with saved IDs. 661 */ 662 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid) 663 { 664 const struct cred *old; 665 struct cred *new; 666 int retval; 667 668 new = prepare_creds(); 669 if (!new) 670 return -ENOMEM; 671 old = current_cred(); 672 673 retval = -EPERM; 674 if (ruid != (uid_t) -1) { 675 new->uid = ruid; 676 if (old->uid != ruid && 677 old->euid != ruid && 678 !nsown_capable(CAP_SETUID)) 679 goto error; 680 } 681 682 if (euid != (uid_t) -1) { 683 new->euid = euid; 684 if (old->uid != euid && 685 old->euid != euid && 686 old->suid != euid && 687 !nsown_capable(CAP_SETUID)) 688 goto error; 689 } 690 691 if (new->uid != old->uid) { 692 retval = set_user(new); 693 if (retval < 0) 694 goto error; 695 } 696 if (ruid != (uid_t) -1 || 697 (euid != (uid_t) -1 && euid != old->uid)) 698 new->suid = new->euid; 699 new->fsuid = new->euid; 700 701 retval = security_task_fix_setuid(new, old, LSM_SETID_RE); 702 if (retval < 0) 703 goto error; 704 705 return commit_creds(new); 706 707 error: 708 abort_creds(new); 709 return retval; 710 } 711 712 /* 713 * setuid() is implemented like SysV with SAVED_IDS 714 * 715 * Note that SAVED_ID's is deficient in that a setuid root program 716 * like sendmail, for example, cannot set its uid to be a normal 717 * user and then switch back, because if you're root, setuid() sets 718 * the saved uid too. If you don't like this, blame the bright people 719 * in the POSIX committee and/or USG. Note that the BSD-style setreuid() 720 * will allow a root program to temporarily drop privileges and be able to 721 * regain them by swapping the real and effective uid. 722 */ 723 SYSCALL_DEFINE1(setuid, uid_t, uid) 724 { 725 const struct cred *old; 726 struct cred *new; 727 int retval; 728 729 new = prepare_creds(); 730 if (!new) 731 return -ENOMEM; 732 old = current_cred(); 733 734 retval = -EPERM; 735 if (nsown_capable(CAP_SETUID)) { 736 new->suid = new->uid = uid; 737 if (uid != old->uid) { 738 retval = set_user(new); 739 if (retval < 0) 740 goto error; 741 } 742 } else if (uid != old->uid && uid != new->suid) { 743 goto error; 744 } 745 746 new->fsuid = new->euid = uid; 747 748 retval = security_task_fix_setuid(new, old, LSM_SETID_ID); 749 if (retval < 0) 750 goto error; 751 752 return commit_creds(new); 753 754 error: 755 abort_creds(new); 756 return retval; 757 } 758 759 760 /* 761 * This function implements a generic ability to update ruid, euid, 762 * and suid. This allows you to implement the 4.4 compatible seteuid(). 763 */ 764 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid) 765 { 766 const struct cred *old; 767 struct cred *new; 768 int retval; 769 770 new = prepare_creds(); 771 if (!new) 772 return -ENOMEM; 773 774 old = current_cred(); 775 776 retval = -EPERM; 777 if (!nsown_capable(CAP_SETUID)) { 778 if (ruid != (uid_t) -1 && ruid != old->uid && 779 ruid != old->euid && ruid != old->suid) 780 goto error; 781 if (euid != (uid_t) -1 && euid != old->uid && 782 euid != old->euid && euid != old->suid) 783 goto error; 784 if (suid != (uid_t) -1 && suid != old->uid && 785 suid != old->euid && suid != old->suid) 786 goto error; 787 } 788 789 if (ruid != (uid_t) -1) { 790 new->uid = ruid; 791 if (ruid != old->uid) { 792 retval = set_user(new); 793 if (retval < 0) 794 goto error; 795 } 796 } 797 if (euid != (uid_t) -1) 798 new->euid = euid; 799 if (suid != (uid_t) -1) 800 new->suid = suid; 801 new->fsuid = new->euid; 802 803 retval = security_task_fix_setuid(new, old, LSM_SETID_RES); 804 if (retval < 0) 805 goto error; 806 807 return commit_creds(new); 808 809 error: 810 abort_creds(new); 811 return retval; 812 } 813 814 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid) 815 { 816 const struct cred *cred = current_cred(); 817 int retval; 818 819 if (!(retval = put_user(cred->uid, ruid)) && 820 !(retval = put_user(cred->euid, euid))) 821 retval = put_user(cred->suid, suid); 822 823 return retval; 824 } 825 826 /* 827 * Same as above, but for rgid, egid, sgid. 828 */ 829 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid) 830 { 831 const struct cred *old; 832 struct cred *new; 833 int retval; 834 835 new = prepare_creds(); 836 if (!new) 837 return -ENOMEM; 838 old = current_cred(); 839 840 retval = -EPERM; 841 if (!nsown_capable(CAP_SETGID)) { 842 if (rgid != (gid_t) -1 && rgid != old->gid && 843 rgid != old->egid && rgid != old->sgid) 844 goto error; 845 if (egid != (gid_t) -1 && egid != old->gid && 846 egid != old->egid && egid != old->sgid) 847 goto error; 848 if (sgid != (gid_t) -1 && sgid != old->gid && 849 sgid != old->egid && sgid != old->sgid) 850 goto error; 851 } 852 853 if (rgid != (gid_t) -1) 854 new->gid = rgid; 855 if (egid != (gid_t) -1) 856 new->egid = egid; 857 if (sgid != (gid_t) -1) 858 new->sgid = sgid; 859 new->fsgid = new->egid; 860 861 return commit_creds(new); 862 863 error: 864 abort_creds(new); 865 return retval; 866 } 867 868 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid) 869 { 870 const struct cred *cred = current_cred(); 871 int retval; 872 873 if (!(retval = put_user(cred->gid, rgid)) && 874 !(retval = put_user(cred->egid, egid))) 875 retval = put_user(cred->sgid, sgid); 876 877 return retval; 878 } 879 880 881 /* 882 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This 883 * is used for "access()" and for the NFS daemon (letting nfsd stay at 884 * whatever uid it wants to). It normally shadows "euid", except when 885 * explicitly set by setfsuid() or for access.. 886 */ 887 SYSCALL_DEFINE1(setfsuid, uid_t, uid) 888 { 889 const struct cred *old; 890 struct cred *new; 891 uid_t old_fsuid; 892 893 new = prepare_creds(); 894 if (!new) 895 return current_fsuid(); 896 old = current_cred(); 897 old_fsuid = old->fsuid; 898 899 if (uid == old->uid || uid == old->euid || 900 uid == old->suid || uid == old->fsuid || 901 nsown_capable(CAP_SETUID)) { 902 if (uid != old_fsuid) { 903 new->fsuid = uid; 904 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0) 905 goto change_okay; 906 } 907 } 908 909 abort_creds(new); 910 return old_fsuid; 911 912 change_okay: 913 commit_creds(new); 914 return old_fsuid; 915 } 916 917 /* 918 * Samma på svenska.. 919 */ 920 SYSCALL_DEFINE1(setfsgid, gid_t, gid) 921 { 922 const struct cred *old; 923 struct cred *new; 924 gid_t old_fsgid; 925 926 new = prepare_creds(); 927 if (!new) 928 return current_fsgid(); 929 old = current_cred(); 930 old_fsgid = old->fsgid; 931 932 if (gid == old->gid || gid == old->egid || 933 gid == old->sgid || gid == old->fsgid || 934 nsown_capable(CAP_SETGID)) { 935 if (gid != old_fsgid) { 936 new->fsgid = gid; 937 goto change_okay; 938 } 939 } 940 941 abort_creds(new); 942 return old_fsgid; 943 944 change_okay: 945 commit_creds(new); 946 return old_fsgid; 947 } 948 949 void do_sys_times(struct tms *tms) 950 { 951 cputime_t tgutime, tgstime, cutime, cstime; 952 953 spin_lock_irq(¤t->sighand->siglock); 954 thread_group_times(current, &tgutime, &tgstime); 955 cutime = current->signal->cutime; 956 cstime = current->signal->cstime; 957 spin_unlock_irq(¤t->sighand->siglock); 958 tms->tms_utime = cputime_to_clock_t(tgutime); 959 tms->tms_stime = cputime_to_clock_t(tgstime); 960 tms->tms_cutime = cputime_to_clock_t(cutime); 961 tms->tms_cstime = cputime_to_clock_t(cstime); 962 } 963 964 SYSCALL_DEFINE1(times, struct tms __user *, tbuf) 965 { 966 if (tbuf) { 967 struct tms tmp; 968 969 do_sys_times(&tmp); 970 if (copy_to_user(tbuf, &tmp, sizeof(struct tms))) 971 return -EFAULT; 972 } 973 force_successful_syscall_return(); 974 return (long) jiffies_64_to_clock_t(get_jiffies_64()); 975 } 976 977 /* 978 * This needs some heavy checking ... 979 * I just haven't the stomach for it. I also don't fully 980 * understand sessions/pgrp etc. Let somebody who does explain it. 981 * 982 * OK, I think I have the protection semantics right.... this is really 983 * only important on a multi-user system anyway, to make sure one user 984 * can't send a signal to a process owned by another. -TYT, 12/12/91 985 * 986 * Auch. Had to add the 'did_exec' flag to conform completely to POSIX. 987 * LBT 04.03.94 988 */ 989 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid) 990 { 991 struct task_struct *p; 992 struct task_struct *group_leader = current->group_leader; 993 struct pid *pgrp; 994 int err; 995 996 if (!pid) 997 pid = task_pid_vnr(group_leader); 998 if (!pgid) 999 pgid = pid; 1000 if (pgid < 0) 1001 return -EINVAL; 1002 rcu_read_lock(); 1003 1004 /* From this point forward we keep holding onto the tasklist lock 1005 * so that our parent does not change from under us. -DaveM 1006 */ 1007 write_lock_irq(&tasklist_lock); 1008 1009 err = -ESRCH; 1010 p = find_task_by_vpid(pid); 1011 if (!p) 1012 goto out; 1013 1014 err = -EINVAL; 1015 if (!thread_group_leader(p)) 1016 goto out; 1017 1018 if (same_thread_group(p->real_parent, group_leader)) { 1019 err = -EPERM; 1020 if (task_session(p) != task_session(group_leader)) 1021 goto out; 1022 err = -EACCES; 1023 if (p->did_exec) 1024 goto out; 1025 } else { 1026 err = -ESRCH; 1027 if (p != group_leader) 1028 goto out; 1029 } 1030 1031 err = -EPERM; 1032 if (p->signal->leader) 1033 goto out; 1034 1035 pgrp = task_pid(p); 1036 if (pgid != pid) { 1037 struct task_struct *g; 1038 1039 pgrp = find_vpid(pgid); 1040 g = pid_task(pgrp, PIDTYPE_PGID); 1041 if (!g || task_session(g) != task_session(group_leader)) 1042 goto out; 1043 } 1044 1045 err = security_task_setpgid(p, pgid); 1046 if (err) 1047 goto out; 1048 1049 if (task_pgrp(p) != pgrp) 1050 change_pid(p, PIDTYPE_PGID, pgrp); 1051 1052 err = 0; 1053 out: 1054 /* All paths lead to here, thus we are safe. -DaveM */ 1055 write_unlock_irq(&tasklist_lock); 1056 rcu_read_unlock(); 1057 return err; 1058 } 1059 1060 SYSCALL_DEFINE1(getpgid, pid_t, pid) 1061 { 1062 struct task_struct *p; 1063 struct pid *grp; 1064 int retval; 1065 1066 rcu_read_lock(); 1067 if (!pid) 1068 grp = task_pgrp(current); 1069 else { 1070 retval = -ESRCH; 1071 p = find_task_by_vpid(pid); 1072 if (!p) 1073 goto out; 1074 grp = task_pgrp(p); 1075 if (!grp) 1076 goto out; 1077 1078 retval = security_task_getpgid(p); 1079 if (retval) 1080 goto out; 1081 } 1082 retval = pid_vnr(grp); 1083 out: 1084 rcu_read_unlock(); 1085 return retval; 1086 } 1087 1088 #ifdef __ARCH_WANT_SYS_GETPGRP 1089 1090 SYSCALL_DEFINE0(getpgrp) 1091 { 1092 return sys_getpgid(0); 1093 } 1094 1095 #endif 1096 1097 SYSCALL_DEFINE1(getsid, pid_t, pid) 1098 { 1099 struct task_struct *p; 1100 struct pid *sid; 1101 int retval; 1102 1103 rcu_read_lock(); 1104 if (!pid) 1105 sid = task_session(current); 1106 else { 1107 retval = -ESRCH; 1108 p = find_task_by_vpid(pid); 1109 if (!p) 1110 goto out; 1111 sid = task_session(p); 1112 if (!sid) 1113 goto out; 1114 1115 retval = security_task_getsid(p); 1116 if (retval) 1117 goto out; 1118 } 1119 retval = pid_vnr(sid); 1120 out: 1121 rcu_read_unlock(); 1122 return retval; 1123 } 1124 1125 SYSCALL_DEFINE0(setsid) 1126 { 1127 struct task_struct *group_leader = current->group_leader; 1128 struct pid *sid = task_pid(group_leader); 1129 pid_t session = pid_vnr(sid); 1130 int err = -EPERM; 1131 1132 write_lock_irq(&tasklist_lock); 1133 /* Fail if I am already a session leader */ 1134 if (group_leader->signal->leader) 1135 goto out; 1136 1137 /* Fail if a process group id already exists that equals the 1138 * proposed session id. 1139 */ 1140 if (pid_task(sid, PIDTYPE_PGID)) 1141 goto out; 1142 1143 group_leader->signal->leader = 1; 1144 __set_special_pids(sid); 1145 1146 proc_clear_tty(group_leader); 1147 1148 err = session; 1149 out: 1150 write_unlock_irq(&tasklist_lock); 1151 if (err > 0) { 1152 proc_sid_connector(group_leader); 1153 sched_autogroup_create_attach(group_leader); 1154 } 1155 return err; 1156 } 1157 1158 DECLARE_RWSEM(uts_sem); 1159 1160 #ifdef COMPAT_UTS_MACHINE 1161 #define override_architecture(name) \ 1162 (personality(current->personality) == PER_LINUX32 && \ 1163 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \ 1164 sizeof(COMPAT_UTS_MACHINE))) 1165 #else 1166 #define override_architecture(name) 0 1167 #endif 1168 1169 /* 1170 * Work around broken programs that cannot handle "Linux 3.0". 1171 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40 1172 */ 1173 static int override_release(char __user *release, int len) 1174 { 1175 int ret = 0; 1176 char buf[65]; 1177 1178 if (current->personality & UNAME26) { 1179 char *rest = UTS_RELEASE; 1180 int ndots = 0; 1181 unsigned v; 1182 1183 while (*rest) { 1184 if (*rest == '.' && ++ndots >= 3) 1185 break; 1186 if (!isdigit(*rest) && *rest != '.') 1187 break; 1188 rest++; 1189 } 1190 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40; 1191 snprintf(buf, len, "2.6.%u%s", v, rest); 1192 ret = copy_to_user(release, buf, len); 1193 } 1194 return ret; 1195 } 1196 1197 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name) 1198 { 1199 int errno = 0; 1200 1201 down_read(&uts_sem); 1202 if (copy_to_user(name, utsname(), sizeof *name)) 1203 errno = -EFAULT; 1204 up_read(&uts_sem); 1205 1206 if (!errno && override_release(name->release, sizeof(name->release))) 1207 errno = -EFAULT; 1208 if (!errno && override_architecture(name)) 1209 errno = -EFAULT; 1210 return errno; 1211 } 1212 1213 #ifdef __ARCH_WANT_SYS_OLD_UNAME 1214 /* 1215 * Old cruft 1216 */ 1217 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name) 1218 { 1219 int error = 0; 1220 1221 if (!name) 1222 return -EFAULT; 1223 1224 down_read(&uts_sem); 1225 if (copy_to_user(name, utsname(), sizeof(*name))) 1226 error = -EFAULT; 1227 up_read(&uts_sem); 1228 1229 if (!error && override_release(name->release, sizeof(name->release))) 1230 error = -EFAULT; 1231 if (!error && override_architecture(name)) 1232 error = -EFAULT; 1233 return error; 1234 } 1235 1236 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name) 1237 { 1238 int error; 1239 1240 if (!name) 1241 return -EFAULT; 1242 if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname))) 1243 return -EFAULT; 1244 1245 down_read(&uts_sem); 1246 error = __copy_to_user(&name->sysname, &utsname()->sysname, 1247 __OLD_UTS_LEN); 1248 error |= __put_user(0, name->sysname + __OLD_UTS_LEN); 1249 error |= __copy_to_user(&name->nodename, &utsname()->nodename, 1250 __OLD_UTS_LEN); 1251 error |= __put_user(0, name->nodename + __OLD_UTS_LEN); 1252 error |= __copy_to_user(&name->release, &utsname()->release, 1253 __OLD_UTS_LEN); 1254 error |= __put_user(0, name->release + __OLD_UTS_LEN); 1255 error |= __copy_to_user(&name->version, &utsname()->version, 1256 __OLD_UTS_LEN); 1257 error |= __put_user(0, name->version + __OLD_UTS_LEN); 1258 error |= __copy_to_user(&name->machine, &utsname()->machine, 1259 __OLD_UTS_LEN); 1260 error |= __put_user(0, name->machine + __OLD_UTS_LEN); 1261 up_read(&uts_sem); 1262 1263 if (!error && override_architecture(name)) 1264 error = -EFAULT; 1265 if (!error && override_release(name->release, sizeof(name->release))) 1266 error = -EFAULT; 1267 return error ? -EFAULT : 0; 1268 } 1269 #endif 1270 1271 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len) 1272 { 1273 int errno; 1274 char tmp[__NEW_UTS_LEN]; 1275 1276 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN)) 1277 return -EPERM; 1278 1279 if (len < 0 || len > __NEW_UTS_LEN) 1280 return -EINVAL; 1281 down_write(&uts_sem); 1282 errno = -EFAULT; 1283 if (!copy_from_user(tmp, name, len)) { 1284 struct new_utsname *u = utsname(); 1285 1286 memcpy(u->nodename, tmp, len); 1287 memset(u->nodename + len, 0, sizeof(u->nodename) - len); 1288 errno = 0; 1289 } 1290 uts_proc_notify(UTS_PROC_HOSTNAME); 1291 up_write(&uts_sem); 1292 return errno; 1293 } 1294 1295 #ifdef __ARCH_WANT_SYS_GETHOSTNAME 1296 1297 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len) 1298 { 1299 int i, errno; 1300 struct new_utsname *u; 1301 1302 if (len < 0) 1303 return -EINVAL; 1304 down_read(&uts_sem); 1305 u = utsname(); 1306 i = 1 + strlen(u->nodename); 1307 if (i > len) 1308 i = len; 1309 errno = 0; 1310 if (copy_to_user(name, u->nodename, i)) 1311 errno = -EFAULT; 1312 up_read(&uts_sem); 1313 return errno; 1314 } 1315 1316 #endif 1317 1318 /* 1319 * Only setdomainname; getdomainname can be implemented by calling 1320 * uname() 1321 */ 1322 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len) 1323 { 1324 int errno; 1325 char tmp[__NEW_UTS_LEN]; 1326 1327 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN)) 1328 return -EPERM; 1329 if (len < 0 || len > __NEW_UTS_LEN) 1330 return -EINVAL; 1331 1332 down_write(&uts_sem); 1333 errno = -EFAULT; 1334 if (!copy_from_user(tmp, name, len)) { 1335 struct new_utsname *u = utsname(); 1336 1337 memcpy(u->domainname, tmp, len); 1338 memset(u->domainname + len, 0, sizeof(u->domainname) - len); 1339 errno = 0; 1340 } 1341 uts_proc_notify(UTS_PROC_DOMAINNAME); 1342 up_write(&uts_sem); 1343 return errno; 1344 } 1345 1346 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim) 1347 { 1348 struct rlimit value; 1349 int ret; 1350 1351 ret = do_prlimit(current, resource, NULL, &value); 1352 if (!ret) 1353 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0; 1354 1355 return ret; 1356 } 1357 1358 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT 1359 1360 /* 1361 * Back compatibility for getrlimit. Needed for some apps. 1362 */ 1363 1364 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource, 1365 struct rlimit __user *, rlim) 1366 { 1367 struct rlimit x; 1368 if (resource >= RLIM_NLIMITS) 1369 return -EINVAL; 1370 1371 task_lock(current->group_leader); 1372 x = current->signal->rlim[resource]; 1373 task_unlock(current->group_leader); 1374 if (x.rlim_cur > 0x7FFFFFFF) 1375 x.rlim_cur = 0x7FFFFFFF; 1376 if (x.rlim_max > 0x7FFFFFFF) 1377 x.rlim_max = 0x7FFFFFFF; 1378 return copy_to_user(rlim, &x, sizeof(x))?-EFAULT:0; 1379 } 1380 1381 #endif 1382 1383 static inline bool rlim64_is_infinity(__u64 rlim64) 1384 { 1385 #if BITS_PER_LONG < 64 1386 return rlim64 >= ULONG_MAX; 1387 #else 1388 return rlim64 == RLIM64_INFINITY; 1389 #endif 1390 } 1391 1392 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64) 1393 { 1394 if (rlim->rlim_cur == RLIM_INFINITY) 1395 rlim64->rlim_cur = RLIM64_INFINITY; 1396 else 1397 rlim64->rlim_cur = rlim->rlim_cur; 1398 if (rlim->rlim_max == RLIM_INFINITY) 1399 rlim64->rlim_max = RLIM64_INFINITY; 1400 else 1401 rlim64->rlim_max = rlim->rlim_max; 1402 } 1403 1404 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim) 1405 { 1406 if (rlim64_is_infinity(rlim64->rlim_cur)) 1407 rlim->rlim_cur = RLIM_INFINITY; 1408 else 1409 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur; 1410 if (rlim64_is_infinity(rlim64->rlim_max)) 1411 rlim->rlim_max = RLIM_INFINITY; 1412 else 1413 rlim->rlim_max = (unsigned long)rlim64->rlim_max; 1414 } 1415 1416 /* make sure you are allowed to change @tsk limits before calling this */ 1417 int do_prlimit(struct task_struct *tsk, unsigned int resource, 1418 struct rlimit *new_rlim, struct rlimit *old_rlim) 1419 { 1420 struct rlimit *rlim; 1421 int retval = 0; 1422 1423 if (resource >= RLIM_NLIMITS) 1424 return -EINVAL; 1425 if (new_rlim) { 1426 if (new_rlim->rlim_cur > new_rlim->rlim_max) 1427 return -EINVAL; 1428 if (resource == RLIMIT_NOFILE && 1429 new_rlim->rlim_max > sysctl_nr_open) 1430 return -EPERM; 1431 } 1432 1433 /* protect tsk->signal and tsk->sighand from disappearing */ 1434 read_lock(&tasklist_lock); 1435 if (!tsk->sighand) { 1436 retval = -ESRCH; 1437 goto out; 1438 } 1439 1440 rlim = tsk->signal->rlim + resource; 1441 task_lock(tsk->group_leader); 1442 if (new_rlim) { 1443 /* Keep the capable check against init_user_ns until 1444 cgroups can contain all limits */ 1445 if (new_rlim->rlim_max > rlim->rlim_max && 1446 !capable(CAP_SYS_RESOURCE)) 1447 retval = -EPERM; 1448 if (!retval) 1449 retval = security_task_setrlimit(tsk->group_leader, 1450 resource, new_rlim); 1451 if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) { 1452 /* 1453 * The caller is asking for an immediate RLIMIT_CPU 1454 * expiry. But we use the zero value to mean "it was 1455 * never set". So let's cheat and make it one second 1456 * instead 1457 */ 1458 new_rlim->rlim_cur = 1; 1459 } 1460 } 1461 if (!retval) { 1462 if (old_rlim) 1463 *old_rlim = *rlim; 1464 if (new_rlim) 1465 *rlim = *new_rlim; 1466 } 1467 task_unlock(tsk->group_leader); 1468 1469 /* 1470 * RLIMIT_CPU handling. Note that the kernel fails to return an error 1471 * code if it rejected the user's attempt to set RLIMIT_CPU. This is a 1472 * very long-standing error, and fixing it now risks breakage of 1473 * applications, so we live with it 1474 */ 1475 if (!retval && new_rlim && resource == RLIMIT_CPU && 1476 new_rlim->rlim_cur != RLIM_INFINITY) 1477 update_rlimit_cpu(tsk, new_rlim->rlim_cur); 1478 out: 1479 read_unlock(&tasklist_lock); 1480 return retval; 1481 } 1482 1483 /* rcu lock must be held */ 1484 static int check_prlimit_permission(struct task_struct *task) 1485 { 1486 const struct cred *cred = current_cred(), *tcred; 1487 1488 if (current == task) 1489 return 0; 1490 1491 tcred = __task_cred(task); 1492 if (cred->user->user_ns == tcred->user->user_ns && 1493 (cred->uid == tcred->euid && 1494 cred->uid == tcred->suid && 1495 cred->uid == tcred->uid && 1496 cred->gid == tcred->egid && 1497 cred->gid == tcred->sgid && 1498 cred->gid == tcred->gid)) 1499 return 0; 1500 if (ns_capable(tcred->user->user_ns, CAP_SYS_RESOURCE)) 1501 return 0; 1502 1503 return -EPERM; 1504 } 1505 1506 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource, 1507 const struct rlimit64 __user *, new_rlim, 1508 struct rlimit64 __user *, old_rlim) 1509 { 1510 struct rlimit64 old64, new64; 1511 struct rlimit old, new; 1512 struct task_struct *tsk; 1513 int ret; 1514 1515 if (new_rlim) { 1516 if (copy_from_user(&new64, new_rlim, sizeof(new64))) 1517 return -EFAULT; 1518 rlim64_to_rlim(&new64, &new); 1519 } 1520 1521 rcu_read_lock(); 1522 tsk = pid ? find_task_by_vpid(pid) : current; 1523 if (!tsk) { 1524 rcu_read_unlock(); 1525 return -ESRCH; 1526 } 1527 ret = check_prlimit_permission(tsk); 1528 if (ret) { 1529 rcu_read_unlock(); 1530 return ret; 1531 } 1532 get_task_struct(tsk); 1533 rcu_read_unlock(); 1534 1535 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL, 1536 old_rlim ? &old : NULL); 1537 1538 if (!ret && old_rlim) { 1539 rlim_to_rlim64(&old, &old64); 1540 if (copy_to_user(old_rlim, &old64, sizeof(old64))) 1541 ret = -EFAULT; 1542 } 1543 1544 put_task_struct(tsk); 1545 return ret; 1546 } 1547 1548 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim) 1549 { 1550 struct rlimit new_rlim; 1551 1552 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim))) 1553 return -EFAULT; 1554 return do_prlimit(current, resource, &new_rlim, NULL); 1555 } 1556 1557 /* 1558 * It would make sense to put struct rusage in the task_struct, 1559 * except that would make the task_struct be *really big*. After 1560 * task_struct gets moved into malloc'ed memory, it would 1561 * make sense to do this. It will make moving the rest of the information 1562 * a lot simpler! (Which we're not doing right now because we're not 1563 * measuring them yet). 1564 * 1565 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have 1566 * races with threads incrementing their own counters. But since word 1567 * reads are atomic, we either get new values or old values and we don't 1568 * care which for the sums. We always take the siglock to protect reading 1569 * the c* fields from p->signal from races with exit.c updating those 1570 * fields when reaping, so a sample either gets all the additions of a 1571 * given child after it's reaped, or none so this sample is before reaping. 1572 * 1573 * Locking: 1574 * We need to take the siglock for CHILDEREN, SELF and BOTH 1575 * for the cases current multithreaded, non-current single threaded 1576 * non-current multithreaded. Thread traversal is now safe with 1577 * the siglock held. 1578 * Strictly speaking, we donot need to take the siglock if we are current and 1579 * single threaded, as no one else can take our signal_struct away, no one 1580 * else can reap the children to update signal->c* counters, and no one else 1581 * can race with the signal-> fields. If we do not take any lock, the 1582 * signal-> fields could be read out of order while another thread was just 1583 * exiting. So we should place a read memory barrier when we avoid the lock. 1584 * On the writer side, write memory barrier is implied in __exit_signal 1585 * as __exit_signal releases the siglock spinlock after updating the signal-> 1586 * fields. But we don't do this yet to keep things simple. 1587 * 1588 */ 1589 1590 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r) 1591 { 1592 r->ru_nvcsw += t->nvcsw; 1593 r->ru_nivcsw += t->nivcsw; 1594 r->ru_minflt += t->min_flt; 1595 r->ru_majflt += t->maj_flt; 1596 r->ru_inblock += task_io_get_inblock(t); 1597 r->ru_oublock += task_io_get_oublock(t); 1598 } 1599 1600 static void k_getrusage(struct task_struct *p, int who, struct rusage *r) 1601 { 1602 struct task_struct *t; 1603 unsigned long flags; 1604 cputime_t tgutime, tgstime, utime, stime; 1605 unsigned long maxrss = 0; 1606 1607 memset((char *) r, 0, sizeof *r); 1608 utime = stime = 0; 1609 1610 if (who == RUSAGE_THREAD) { 1611 task_times(current, &utime, &stime); 1612 accumulate_thread_rusage(p, r); 1613 maxrss = p->signal->maxrss; 1614 goto out; 1615 } 1616 1617 if (!lock_task_sighand(p, &flags)) 1618 return; 1619 1620 switch (who) { 1621 case RUSAGE_BOTH: 1622 case RUSAGE_CHILDREN: 1623 utime = p->signal->cutime; 1624 stime = p->signal->cstime; 1625 r->ru_nvcsw = p->signal->cnvcsw; 1626 r->ru_nivcsw = p->signal->cnivcsw; 1627 r->ru_minflt = p->signal->cmin_flt; 1628 r->ru_majflt = p->signal->cmaj_flt; 1629 r->ru_inblock = p->signal->cinblock; 1630 r->ru_oublock = p->signal->coublock; 1631 maxrss = p->signal->cmaxrss; 1632 1633 if (who == RUSAGE_CHILDREN) 1634 break; 1635 1636 case RUSAGE_SELF: 1637 thread_group_times(p, &tgutime, &tgstime); 1638 utime += tgutime; 1639 stime += tgstime; 1640 r->ru_nvcsw += p->signal->nvcsw; 1641 r->ru_nivcsw += p->signal->nivcsw; 1642 r->ru_minflt += p->signal->min_flt; 1643 r->ru_majflt += p->signal->maj_flt; 1644 r->ru_inblock += p->signal->inblock; 1645 r->ru_oublock += p->signal->oublock; 1646 if (maxrss < p->signal->maxrss) 1647 maxrss = p->signal->maxrss; 1648 t = p; 1649 do { 1650 accumulate_thread_rusage(t, r); 1651 t = next_thread(t); 1652 } while (t != p); 1653 break; 1654 1655 default: 1656 BUG(); 1657 } 1658 unlock_task_sighand(p, &flags); 1659 1660 out: 1661 cputime_to_timeval(utime, &r->ru_utime); 1662 cputime_to_timeval(stime, &r->ru_stime); 1663 1664 if (who != RUSAGE_CHILDREN) { 1665 struct mm_struct *mm = get_task_mm(p); 1666 if (mm) { 1667 setmax_mm_hiwater_rss(&maxrss, mm); 1668 mmput(mm); 1669 } 1670 } 1671 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */ 1672 } 1673 1674 int getrusage(struct task_struct *p, int who, struct rusage __user *ru) 1675 { 1676 struct rusage r; 1677 k_getrusage(p, who, &r); 1678 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0; 1679 } 1680 1681 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru) 1682 { 1683 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN && 1684 who != RUSAGE_THREAD) 1685 return -EINVAL; 1686 return getrusage(current, who, ru); 1687 } 1688 1689 SYSCALL_DEFINE1(umask, int, mask) 1690 { 1691 mask = xchg(¤t->fs->umask, mask & S_IRWXUGO); 1692 return mask; 1693 } 1694 1695 #ifdef CONFIG_CHECKPOINT_RESTORE 1696 static int prctl_set_mm(int opt, unsigned long addr, 1697 unsigned long arg4, unsigned long arg5) 1698 { 1699 unsigned long rlim = rlimit(RLIMIT_DATA); 1700 unsigned long vm_req_flags; 1701 unsigned long vm_bad_flags; 1702 struct vm_area_struct *vma; 1703 int error = 0; 1704 struct mm_struct *mm = current->mm; 1705 1706 if (arg4 | arg5) 1707 return -EINVAL; 1708 1709 if (!capable(CAP_SYS_RESOURCE)) 1710 return -EPERM; 1711 1712 if (addr >= TASK_SIZE) 1713 return -EINVAL; 1714 1715 down_read(&mm->mmap_sem); 1716 vma = find_vma(mm, addr); 1717 1718 if (opt != PR_SET_MM_START_BRK && opt != PR_SET_MM_BRK) { 1719 /* It must be existing VMA */ 1720 if (!vma || vma->vm_start > addr) 1721 goto out; 1722 } 1723 1724 error = -EINVAL; 1725 switch (opt) { 1726 case PR_SET_MM_START_CODE: 1727 case PR_SET_MM_END_CODE: 1728 vm_req_flags = VM_READ | VM_EXEC; 1729 vm_bad_flags = VM_WRITE | VM_MAYSHARE; 1730 1731 if ((vma->vm_flags & vm_req_flags) != vm_req_flags || 1732 (vma->vm_flags & vm_bad_flags)) 1733 goto out; 1734 1735 if (opt == PR_SET_MM_START_CODE) 1736 mm->start_code = addr; 1737 else 1738 mm->end_code = addr; 1739 break; 1740 1741 case PR_SET_MM_START_DATA: 1742 case PR_SET_MM_END_DATA: 1743 vm_req_flags = VM_READ | VM_WRITE; 1744 vm_bad_flags = VM_EXEC | VM_MAYSHARE; 1745 1746 if ((vma->vm_flags & vm_req_flags) != vm_req_flags || 1747 (vma->vm_flags & vm_bad_flags)) 1748 goto out; 1749 1750 if (opt == PR_SET_MM_START_DATA) 1751 mm->start_data = addr; 1752 else 1753 mm->end_data = addr; 1754 break; 1755 1756 case PR_SET_MM_START_STACK: 1757 1758 #ifdef CONFIG_STACK_GROWSUP 1759 vm_req_flags = VM_READ | VM_WRITE | VM_GROWSUP; 1760 #else 1761 vm_req_flags = VM_READ | VM_WRITE | VM_GROWSDOWN; 1762 #endif 1763 if ((vma->vm_flags & vm_req_flags) != vm_req_flags) 1764 goto out; 1765 1766 mm->start_stack = addr; 1767 break; 1768 1769 case PR_SET_MM_START_BRK: 1770 if (addr <= mm->end_data) 1771 goto out; 1772 1773 if (rlim < RLIM_INFINITY && 1774 (mm->brk - addr) + 1775 (mm->end_data - mm->start_data) > rlim) 1776 goto out; 1777 1778 mm->start_brk = addr; 1779 break; 1780 1781 case PR_SET_MM_BRK: 1782 if (addr <= mm->end_data) 1783 goto out; 1784 1785 if (rlim < RLIM_INFINITY && 1786 (addr - mm->start_brk) + 1787 (mm->end_data - mm->start_data) > rlim) 1788 goto out; 1789 1790 mm->brk = addr; 1791 break; 1792 1793 default: 1794 error = -EINVAL; 1795 goto out; 1796 } 1797 1798 error = 0; 1799 1800 out: 1801 up_read(&mm->mmap_sem); 1802 1803 return error; 1804 } 1805 #else /* CONFIG_CHECKPOINT_RESTORE */ 1806 static int prctl_set_mm(int opt, unsigned long addr, 1807 unsigned long arg4, unsigned long arg5) 1808 { 1809 return -EINVAL; 1810 } 1811 #endif 1812 1813 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, 1814 unsigned long, arg4, unsigned long, arg5) 1815 { 1816 struct task_struct *me = current; 1817 unsigned char comm[sizeof(me->comm)]; 1818 long error; 1819 1820 error = security_task_prctl(option, arg2, arg3, arg4, arg5); 1821 if (error != -ENOSYS) 1822 return error; 1823 1824 error = 0; 1825 switch (option) { 1826 case PR_SET_PDEATHSIG: 1827 if (!valid_signal(arg2)) { 1828 error = -EINVAL; 1829 break; 1830 } 1831 me->pdeath_signal = arg2; 1832 error = 0; 1833 break; 1834 case PR_GET_PDEATHSIG: 1835 error = put_user(me->pdeath_signal, (int __user *)arg2); 1836 break; 1837 case PR_GET_DUMPABLE: 1838 error = get_dumpable(me->mm); 1839 break; 1840 case PR_SET_DUMPABLE: 1841 if (arg2 < 0 || arg2 > 1) { 1842 error = -EINVAL; 1843 break; 1844 } 1845 set_dumpable(me->mm, arg2); 1846 error = 0; 1847 break; 1848 1849 case PR_SET_UNALIGN: 1850 error = SET_UNALIGN_CTL(me, arg2); 1851 break; 1852 case PR_GET_UNALIGN: 1853 error = GET_UNALIGN_CTL(me, arg2); 1854 break; 1855 case PR_SET_FPEMU: 1856 error = SET_FPEMU_CTL(me, arg2); 1857 break; 1858 case PR_GET_FPEMU: 1859 error = GET_FPEMU_CTL(me, arg2); 1860 break; 1861 case PR_SET_FPEXC: 1862 error = SET_FPEXC_CTL(me, arg2); 1863 break; 1864 case PR_GET_FPEXC: 1865 error = GET_FPEXC_CTL(me, arg2); 1866 break; 1867 case PR_GET_TIMING: 1868 error = PR_TIMING_STATISTICAL; 1869 break; 1870 case PR_SET_TIMING: 1871 if (arg2 != PR_TIMING_STATISTICAL) 1872 error = -EINVAL; 1873 else 1874 error = 0; 1875 break; 1876 1877 case PR_SET_NAME: 1878 comm[sizeof(me->comm)-1] = 0; 1879 if (strncpy_from_user(comm, (char __user *)arg2, 1880 sizeof(me->comm) - 1) < 0) 1881 return -EFAULT; 1882 set_task_comm(me, comm); 1883 proc_comm_connector(me); 1884 return 0; 1885 case PR_GET_NAME: 1886 get_task_comm(comm, me); 1887 if (copy_to_user((char __user *)arg2, comm, 1888 sizeof(comm))) 1889 return -EFAULT; 1890 return 0; 1891 case PR_GET_ENDIAN: 1892 error = GET_ENDIAN(me, arg2); 1893 break; 1894 case PR_SET_ENDIAN: 1895 error = SET_ENDIAN(me, arg2); 1896 break; 1897 1898 case PR_GET_SECCOMP: 1899 error = prctl_get_seccomp(); 1900 break; 1901 case PR_SET_SECCOMP: 1902 error = prctl_set_seccomp(arg2); 1903 break; 1904 case PR_GET_TSC: 1905 error = GET_TSC_CTL(arg2); 1906 break; 1907 case PR_SET_TSC: 1908 error = SET_TSC_CTL(arg2); 1909 break; 1910 case PR_TASK_PERF_EVENTS_DISABLE: 1911 error = perf_event_task_disable(); 1912 break; 1913 case PR_TASK_PERF_EVENTS_ENABLE: 1914 error = perf_event_task_enable(); 1915 break; 1916 case PR_GET_TIMERSLACK: 1917 error = current->timer_slack_ns; 1918 break; 1919 case PR_SET_TIMERSLACK: 1920 if (arg2 <= 0) 1921 current->timer_slack_ns = 1922 current->default_timer_slack_ns; 1923 else 1924 current->timer_slack_ns = arg2; 1925 error = 0; 1926 break; 1927 case PR_MCE_KILL: 1928 if (arg4 | arg5) 1929 return -EINVAL; 1930 switch (arg2) { 1931 case PR_MCE_KILL_CLEAR: 1932 if (arg3 != 0) 1933 return -EINVAL; 1934 current->flags &= ~PF_MCE_PROCESS; 1935 break; 1936 case PR_MCE_KILL_SET: 1937 current->flags |= PF_MCE_PROCESS; 1938 if (arg3 == PR_MCE_KILL_EARLY) 1939 current->flags |= PF_MCE_EARLY; 1940 else if (arg3 == PR_MCE_KILL_LATE) 1941 current->flags &= ~PF_MCE_EARLY; 1942 else if (arg3 == PR_MCE_KILL_DEFAULT) 1943 current->flags &= 1944 ~(PF_MCE_EARLY|PF_MCE_PROCESS); 1945 else 1946 return -EINVAL; 1947 break; 1948 default: 1949 return -EINVAL; 1950 } 1951 error = 0; 1952 break; 1953 case PR_MCE_KILL_GET: 1954 if (arg2 | arg3 | arg4 | arg5) 1955 return -EINVAL; 1956 if (current->flags & PF_MCE_PROCESS) 1957 error = (current->flags & PF_MCE_EARLY) ? 1958 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE; 1959 else 1960 error = PR_MCE_KILL_DEFAULT; 1961 break; 1962 case PR_SET_MM: 1963 error = prctl_set_mm(arg2, arg3, arg4, arg5); 1964 break; 1965 default: 1966 error = -EINVAL; 1967 break; 1968 } 1969 return error; 1970 } 1971 1972 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep, 1973 struct getcpu_cache __user *, unused) 1974 { 1975 int err = 0; 1976 int cpu = raw_smp_processor_id(); 1977 if (cpup) 1978 err |= put_user(cpu, cpup); 1979 if (nodep) 1980 err |= put_user(cpu_to_node(cpu), nodep); 1981 return err ? -EFAULT : 0; 1982 } 1983 1984 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; 1985 1986 static void argv_cleanup(struct subprocess_info *info) 1987 { 1988 argv_free(info->argv); 1989 } 1990 1991 /** 1992 * orderly_poweroff - Trigger an orderly system poweroff 1993 * @force: force poweroff if command execution fails 1994 * 1995 * This may be called from any context to trigger a system shutdown. 1996 * If the orderly shutdown fails, it will force an immediate shutdown. 1997 */ 1998 int orderly_poweroff(bool force) 1999 { 2000 int argc; 2001 char **argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc); 2002 static char *envp[] = { 2003 "HOME=/", 2004 "PATH=/sbin:/bin:/usr/sbin:/usr/bin", 2005 NULL 2006 }; 2007 int ret = -ENOMEM; 2008 struct subprocess_info *info; 2009 2010 if (argv == NULL) { 2011 printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n", 2012 __func__, poweroff_cmd); 2013 goto out; 2014 } 2015 2016 info = call_usermodehelper_setup(argv[0], argv, envp, GFP_ATOMIC); 2017 if (info == NULL) { 2018 argv_free(argv); 2019 goto out; 2020 } 2021 2022 call_usermodehelper_setfns(info, NULL, argv_cleanup, NULL); 2023 2024 ret = call_usermodehelper_exec(info, UMH_NO_WAIT); 2025 2026 out: 2027 if (ret && force) { 2028 printk(KERN_WARNING "Failed to start orderly shutdown: " 2029 "forcing the issue\n"); 2030 2031 /* I guess this should try to kick off some daemon to 2032 sync and poweroff asap. Or not even bother syncing 2033 if we're doing an emergency shutdown? */ 2034 emergency_sync(); 2035 kernel_power_off(); 2036 } 2037 2038 return ret; 2039 } 2040 EXPORT_SYMBOL_GPL(orderly_poweroff); 2041