1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/kernel/sys.c 4 * 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 */ 7 8 #include <linux/export.h> 9 #include <linux/mm.h> 10 #include <linux/mm_inline.h> 11 #include <linux/utsname.h> 12 #include <linux/mman.h> 13 #include <linux/reboot.h> 14 #include <linux/prctl.h> 15 #include <linux/highuid.h> 16 #include <linux/fs.h> 17 #include <linux/kmod.h> 18 #include <linux/ksm.h> 19 #include <linux/perf_event.h> 20 #include <linux/resource.h> 21 #include <linux/kernel.h> 22 #include <linux/workqueue.h> 23 #include <linux/capability.h> 24 #include <linux/device.h> 25 #include <linux/key.h> 26 #include <linux/times.h> 27 #include <linux/posix-timers.h> 28 #include <linux/security.h> 29 #include <linux/random.h> 30 #include <linux/suspend.h> 31 #include <linux/tty.h> 32 #include <linux/signal.h> 33 #include <linux/cn_proc.h> 34 #include <linux/getcpu.h> 35 #include <linux/task_io_accounting_ops.h> 36 #include <linux/seccomp.h> 37 #include <linux/cpu.h> 38 #include <linux/personality.h> 39 #include <linux/ptrace.h> 40 #include <linux/fs_struct.h> 41 #include <linux/file.h> 42 #include <linux/mount.h> 43 #include <linux/gfp.h> 44 #include <linux/syscore_ops.h> 45 #include <linux/version.h> 46 #include <linux/ctype.h> 47 #include <linux/syscall_user_dispatch.h> 48 49 #include <linux/compat.h> 50 #include <linux/syscalls.h> 51 #include <linux/kprobes.h> 52 #include <linux/user_namespace.h> 53 #include <linux/time_namespace.h> 54 #include <linux/binfmts.h> 55 56 #include <linux/sched.h> 57 #include <linux/sched/autogroup.h> 58 #include <linux/sched/loadavg.h> 59 #include <linux/sched/stat.h> 60 #include <linux/sched/mm.h> 61 #include <linux/sched/coredump.h> 62 #include <linux/sched/task.h> 63 #include <linux/sched/cputime.h> 64 #include <linux/rcupdate.h> 65 #include <linux/uidgid.h> 66 #include <linux/cred.h> 67 68 #include <linux/nospec.h> 69 70 #include <linux/kmsg_dump.h> 71 /* Move somewhere else to avoid recompiling? */ 72 #include <generated/utsrelease.h> 73 74 #include <linux/uaccess.h> 75 #include <asm/io.h> 76 #include <asm/unistd.h> 77 78 #include "uid16.h" 79 80 #ifndef SET_UNALIGN_CTL 81 # define SET_UNALIGN_CTL(a, b) (-EINVAL) 82 #endif 83 #ifndef GET_UNALIGN_CTL 84 # define GET_UNALIGN_CTL(a, b) (-EINVAL) 85 #endif 86 #ifndef SET_FPEMU_CTL 87 # define SET_FPEMU_CTL(a, b) (-EINVAL) 88 #endif 89 #ifndef GET_FPEMU_CTL 90 # define GET_FPEMU_CTL(a, b) (-EINVAL) 91 #endif 92 #ifndef SET_FPEXC_CTL 93 # define SET_FPEXC_CTL(a, b) (-EINVAL) 94 #endif 95 #ifndef GET_FPEXC_CTL 96 # define GET_FPEXC_CTL(a, b) (-EINVAL) 97 #endif 98 #ifndef GET_ENDIAN 99 # define GET_ENDIAN(a, b) (-EINVAL) 100 #endif 101 #ifndef SET_ENDIAN 102 # define SET_ENDIAN(a, b) (-EINVAL) 103 #endif 104 #ifndef GET_TSC_CTL 105 # define GET_TSC_CTL(a) (-EINVAL) 106 #endif 107 #ifndef SET_TSC_CTL 108 # define SET_TSC_CTL(a) (-EINVAL) 109 #endif 110 #ifndef GET_FP_MODE 111 # define GET_FP_MODE(a) (-EINVAL) 112 #endif 113 #ifndef SET_FP_MODE 114 # define SET_FP_MODE(a,b) (-EINVAL) 115 #endif 116 #ifndef SVE_SET_VL 117 # define SVE_SET_VL(a) (-EINVAL) 118 #endif 119 #ifndef SVE_GET_VL 120 # define SVE_GET_VL() (-EINVAL) 121 #endif 122 #ifndef SME_SET_VL 123 # define SME_SET_VL(a) (-EINVAL) 124 #endif 125 #ifndef SME_GET_VL 126 # define SME_GET_VL() (-EINVAL) 127 #endif 128 #ifndef PAC_RESET_KEYS 129 # define PAC_RESET_KEYS(a, b) (-EINVAL) 130 #endif 131 #ifndef PAC_SET_ENABLED_KEYS 132 # define PAC_SET_ENABLED_KEYS(a, b, c) (-EINVAL) 133 #endif 134 #ifndef PAC_GET_ENABLED_KEYS 135 # define PAC_GET_ENABLED_KEYS(a) (-EINVAL) 136 #endif 137 #ifndef SET_TAGGED_ADDR_CTRL 138 # define SET_TAGGED_ADDR_CTRL(a) (-EINVAL) 139 #endif 140 #ifndef GET_TAGGED_ADDR_CTRL 141 # define GET_TAGGED_ADDR_CTRL() (-EINVAL) 142 #endif 143 144 /* 145 * this is where the system-wide overflow UID and GID are defined, for 146 * architectures that now have 32-bit UID/GID but didn't in the past 147 */ 148 149 int overflowuid = DEFAULT_OVERFLOWUID; 150 int overflowgid = DEFAULT_OVERFLOWGID; 151 152 EXPORT_SYMBOL(overflowuid); 153 EXPORT_SYMBOL(overflowgid); 154 155 /* 156 * the same as above, but for filesystems which can only store a 16-bit 157 * UID and GID. as such, this is needed on all architectures 158 */ 159 160 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID; 161 int fs_overflowgid = DEFAULT_FS_OVERFLOWGID; 162 163 EXPORT_SYMBOL(fs_overflowuid); 164 EXPORT_SYMBOL(fs_overflowgid); 165 166 /* 167 * Returns true if current's euid is same as p's uid or euid, 168 * or has CAP_SYS_NICE to p's user_ns. 169 * 170 * Called with rcu_read_lock, creds are safe 171 */ 172 static bool set_one_prio_perm(struct task_struct *p) 173 { 174 const struct cred *cred = current_cred(), *pcred = __task_cred(p); 175 176 if (uid_eq(pcred->uid, cred->euid) || 177 uid_eq(pcred->euid, cred->euid)) 178 return true; 179 if (ns_capable(pcred->user_ns, CAP_SYS_NICE)) 180 return true; 181 return false; 182 } 183 184 /* 185 * set the priority of a task 186 * - the caller must hold the RCU read lock 187 */ 188 static int set_one_prio(struct task_struct *p, int niceval, int error) 189 { 190 int no_nice; 191 192 if (!set_one_prio_perm(p)) { 193 error = -EPERM; 194 goto out; 195 } 196 if (niceval < task_nice(p) && !can_nice(p, niceval)) { 197 error = -EACCES; 198 goto out; 199 } 200 no_nice = security_task_setnice(p, niceval); 201 if (no_nice) { 202 error = no_nice; 203 goto out; 204 } 205 if (error == -ESRCH) 206 error = 0; 207 set_user_nice(p, niceval); 208 out: 209 return error; 210 } 211 212 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval) 213 { 214 struct task_struct *g, *p; 215 struct user_struct *user; 216 const struct cred *cred = current_cred(); 217 int error = -EINVAL; 218 struct pid *pgrp; 219 kuid_t uid; 220 221 if (which > PRIO_USER || which < PRIO_PROCESS) 222 goto out; 223 224 /* normalize: avoid signed division (rounding problems) */ 225 error = -ESRCH; 226 if (niceval < MIN_NICE) 227 niceval = MIN_NICE; 228 if (niceval > MAX_NICE) 229 niceval = MAX_NICE; 230 231 rcu_read_lock(); 232 switch (which) { 233 case PRIO_PROCESS: 234 if (who) 235 p = find_task_by_vpid(who); 236 else 237 p = current; 238 if (p) 239 error = set_one_prio(p, niceval, error); 240 break; 241 case PRIO_PGRP: 242 if (who) 243 pgrp = find_vpid(who); 244 else 245 pgrp = task_pgrp(current); 246 read_lock(&tasklist_lock); 247 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { 248 error = set_one_prio(p, niceval, error); 249 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); 250 read_unlock(&tasklist_lock); 251 break; 252 case PRIO_USER: 253 uid = make_kuid(cred->user_ns, who); 254 user = cred->user; 255 if (!who) 256 uid = cred->uid; 257 else if (!uid_eq(uid, cred->uid)) { 258 user = find_user(uid); 259 if (!user) 260 goto out_unlock; /* No processes for this user */ 261 } 262 for_each_process_thread(g, p) { 263 if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) 264 error = set_one_prio(p, niceval, error); 265 } 266 if (!uid_eq(uid, cred->uid)) 267 free_uid(user); /* For find_user() */ 268 break; 269 } 270 out_unlock: 271 rcu_read_unlock(); 272 out: 273 return error; 274 } 275 276 /* 277 * Ugh. To avoid negative return values, "getpriority()" will 278 * not return the normal nice-value, but a negated value that 279 * has been offset by 20 (ie it returns 40..1 instead of -20..19) 280 * to stay compatible. 281 */ 282 SYSCALL_DEFINE2(getpriority, int, which, int, who) 283 { 284 struct task_struct *g, *p; 285 struct user_struct *user; 286 const struct cred *cred = current_cred(); 287 long niceval, retval = -ESRCH; 288 struct pid *pgrp; 289 kuid_t uid; 290 291 if (which > PRIO_USER || which < PRIO_PROCESS) 292 return -EINVAL; 293 294 rcu_read_lock(); 295 switch (which) { 296 case PRIO_PROCESS: 297 if (who) 298 p = find_task_by_vpid(who); 299 else 300 p = current; 301 if (p) { 302 niceval = nice_to_rlimit(task_nice(p)); 303 if (niceval > retval) 304 retval = niceval; 305 } 306 break; 307 case PRIO_PGRP: 308 if (who) 309 pgrp = find_vpid(who); 310 else 311 pgrp = task_pgrp(current); 312 read_lock(&tasklist_lock); 313 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { 314 niceval = nice_to_rlimit(task_nice(p)); 315 if (niceval > retval) 316 retval = niceval; 317 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); 318 read_unlock(&tasklist_lock); 319 break; 320 case PRIO_USER: 321 uid = make_kuid(cred->user_ns, who); 322 user = cred->user; 323 if (!who) 324 uid = cred->uid; 325 else if (!uid_eq(uid, cred->uid)) { 326 user = find_user(uid); 327 if (!user) 328 goto out_unlock; /* No processes for this user */ 329 } 330 for_each_process_thread(g, p) { 331 if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) { 332 niceval = nice_to_rlimit(task_nice(p)); 333 if (niceval > retval) 334 retval = niceval; 335 } 336 } 337 if (!uid_eq(uid, cred->uid)) 338 free_uid(user); /* for find_user() */ 339 break; 340 } 341 out_unlock: 342 rcu_read_unlock(); 343 344 return retval; 345 } 346 347 /* 348 * Unprivileged users may change the real gid to the effective gid 349 * or vice versa. (BSD-style) 350 * 351 * If you set the real gid at all, or set the effective gid to a value not 352 * equal to the real gid, then the saved gid is set to the new effective gid. 353 * 354 * This makes it possible for a setgid program to completely drop its 355 * privileges, which is often a useful assertion to make when you are doing 356 * a security audit over a program. 357 * 358 * The general idea is that a program which uses just setregid() will be 359 * 100% compatible with BSD. A program which uses just setgid() will be 360 * 100% compatible with POSIX with saved IDs. 361 * 362 * SMP: There are not races, the GIDs are checked only by filesystem 363 * operations (as far as semantic preservation is concerned). 364 */ 365 #ifdef CONFIG_MULTIUSER 366 long __sys_setregid(gid_t rgid, gid_t egid) 367 { 368 struct user_namespace *ns = current_user_ns(); 369 const struct cred *old; 370 struct cred *new; 371 int retval; 372 kgid_t krgid, kegid; 373 374 krgid = make_kgid(ns, rgid); 375 kegid = make_kgid(ns, egid); 376 377 if ((rgid != (gid_t) -1) && !gid_valid(krgid)) 378 return -EINVAL; 379 if ((egid != (gid_t) -1) && !gid_valid(kegid)) 380 return -EINVAL; 381 382 new = prepare_creds(); 383 if (!new) 384 return -ENOMEM; 385 old = current_cred(); 386 387 retval = -EPERM; 388 if (rgid != (gid_t) -1) { 389 if (gid_eq(old->gid, krgid) || 390 gid_eq(old->egid, krgid) || 391 ns_capable_setid(old->user_ns, CAP_SETGID)) 392 new->gid = krgid; 393 else 394 goto error; 395 } 396 if (egid != (gid_t) -1) { 397 if (gid_eq(old->gid, kegid) || 398 gid_eq(old->egid, kegid) || 399 gid_eq(old->sgid, kegid) || 400 ns_capable_setid(old->user_ns, CAP_SETGID)) 401 new->egid = kegid; 402 else 403 goto error; 404 } 405 406 if (rgid != (gid_t) -1 || 407 (egid != (gid_t) -1 && !gid_eq(kegid, old->gid))) 408 new->sgid = new->egid; 409 new->fsgid = new->egid; 410 411 retval = security_task_fix_setgid(new, old, LSM_SETID_RE); 412 if (retval < 0) 413 goto error; 414 415 return commit_creds(new); 416 417 error: 418 abort_creds(new); 419 return retval; 420 } 421 422 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid) 423 { 424 return __sys_setregid(rgid, egid); 425 } 426 427 /* 428 * setgid() is implemented like SysV w/ SAVED_IDS 429 * 430 * SMP: Same implicit races as above. 431 */ 432 long __sys_setgid(gid_t gid) 433 { 434 struct user_namespace *ns = current_user_ns(); 435 const struct cred *old; 436 struct cred *new; 437 int retval; 438 kgid_t kgid; 439 440 kgid = make_kgid(ns, gid); 441 if (!gid_valid(kgid)) 442 return -EINVAL; 443 444 new = prepare_creds(); 445 if (!new) 446 return -ENOMEM; 447 old = current_cred(); 448 449 retval = -EPERM; 450 if (ns_capable_setid(old->user_ns, CAP_SETGID)) 451 new->gid = new->egid = new->sgid = new->fsgid = kgid; 452 else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) 453 new->egid = new->fsgid = kgid; 454 else 455 goto error; 456 457 retval = security_task_fix_setgid(new, old, LSM_SETID_ID); 458 if (retval < 0) 459 goto error; 460 461 return commit_creds(new); 462 463 error: 464 abort_creds(new); 465 return retval; 466 } 467 468 SYSCALL_DEFINE1(setgid, gid_t, gid) 469 { 470 return __sys_setgid(gid); 471 } 472 473 /* 474 * change the user struct in a credentials set to match the new UID 475 */ 476 static int set_user(struct cred *new) 477 { 478 struct user_struct *new_user; 479 480 new_user = alloc_uid(new->uid); 481 if (!new_user) 482 return -EAGAIN; 483 484 free_uid(new->user); 485 new->user = new_user; 486 return 0; 487 } 488 489 static void flag_nproc_exceeded(struct cred *new) 490 { 491 if (new->ucounts == current_ucounts()) 492 return; 493 494 /* 495 * We don't fail in case of NPROC limit excess here because too many 496 * poorly written programs don't check set*uid() return code, assuming 497 * it never fails if called by root. We may still enforce NPROC limit 498 * for programs doing set*uid()+execve() by harmlessly deferring the 499 * failure to the execve() stage. 500 */ 501 if (is_rlimit_overlimit(new->ucounts, UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC)) && 502 new->user != INIT_USER) 503 current->flags |= PF_NPROC_EXCEEDED; 504 else 505 current->flags &= ~PF_NPROC_EXCEEDED; 506 } 507 508 /* 509 * Unprivileged users may change the real uid to the effective uid 510 * or vice versa. (BSD-style) 511 * 512 * If you set the real uid at all, or set the effective uid to a value not 513 * equal to the real uid, then the saved uid is set to the new effective uid. 514 * 515 * This makes it possible for a setuid program to completely drop its 516 * privileges, which is often a useful assertion to make when you are doing 517 * a security audit over a program. 518 * 519 * The general idea is that a program which uses just setreuid() will be 520 * 100% compatible with BSD. A program which uses just setuid() will be 521 * 100% compatible with POSIX with saved IDs. 522 */ 523 long __sys_setreuid(uid_t ruid, uid_t euid) 524 { 525 struct user_namespace *ns = current_user_ns(); 526 const struct cred *old; 527 struct cred *new; 528 int retval; 529 kuid_t kruid, keuid; 530 531 kruid = make_kuid(ns, ruid); 532 keuid = make_kuid(ns, euid); 533 534 if ((ruid != (uid_t) -1) && !uid_valid(kruid)) 535 return -EINVAL; 536 if ((euid != (uid_t) -1) && !uid_valid(keuid)) 537 return -EINVAL; 538 539 new = prepare_creds(); 540 if (!new) 541 return -ENOMEM; 542 old = current_cred(); 543 544 retval = -EPERM; 545 if (ruid != (uid_t) -1) { 546 new->uid = kruid; 547 if (!uid_eq(old->uid, kruid) && 548 !uid_eq(old->euid, kruid) && 549 !ns_capable_setid(old->user_ns, CAP_SETUID)) 550 goto error; 551 } 552 553 if (euid != (uid_t) -1) { 554 new->euid = keuid; 555 if (!uid_eq(old->uid, keuid) && 556 !uid_eq(old->euid, keuid) && 557 !uid_eq(old->suid, keuid) && 558 !ns_capable_setid(old->user_ns, CAP_SETUID)) 559 goto error; 560 } 561 562 if (!uid_eq(new->uid, old->uid)) { 563 retval = set_user(new); 564 if (retval < 0) 565 goto error; 566 } 567 if (ruid != (uid_t) -1 || 568 (euid != (uid_t) -1 && !uid_eq(keuid, old->uid))) 569 new->suid = new->euid; 570 new->fsuid = new->euid; 571 572 retval = security_task_fix_setuid(new, old, LSM_SETID_RE); 573 if (retval < 0) 574 goto error; 575 576 retval = set_cred_ucounts(new); 577 if (retval < 0) 578 goto error; 579 580 flag_nproc_exceeded(new); 581 return commit_creds(new); 582 583 error: 584 abort_creds(new); 585 return retval; 586 } 587 588 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid) 589 { 590 return __sys_setreuid(ruid, euid); 591 } 592 593 /* 594 * setuid() is implemented like SysV with SAVED_IDS 595 * 596 * Note that SAVED_ID's is deficient in that a setuid root program 597 * like sendmail, for example, cannot set its uid to be a normal 598 * user and then switch back, because if you're root, setuid() sets 599 * the saved uid too. If you don't like this, blame the bright people 600 * in the POSIX committee and/or USG. Note that the BSD-style setreuid() 601 * will allow a root program to temporarily drop privileges and be able to 602 * regain them by swapping the real and effective uid. 603 */ 604 long __sys_setuid(uid_t uid) 605 { 606 struct user_namespace *ns = current_user_ns(); 607 const struct cred *old; 608 struct cred *new; 609 int retval; 610 kuid_t kuid; 611 612 kuid = make_kuid(ns, uid); 613 if (!uid_valid(kuid)) 614 return -EINVAL; 615 616 new = prepare_creds(); 617 if (!new) 618 return -ENOMEM; 619 old = current_cred(); 620 621 retval = -EPERM; 622 if (ns_capable_setid(old->user_ns, CAP_SETUID)) { 623 new->suid = new->uid = kuid; 624 if (!uid_eq(kuid, old->uid)) { 625 retval = set_user(new); 626 if (retval < 0) 627 goto error; 628 } 629 } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) { 630 goto error; 631 } 632 633 new->fsuid = new->euid = kuid; 634 635 retval = security_task_fix_setuid(new, old, LSM_SETID_ID); 636 if (retval < 0) 637 goto error; 638 639 retval = set_cred_ucounts(new); 640 if (retval < 0) 641 goto error; 642 643 flag_nproc_exceeded(new); 644 return commit_creds(new); 645 646 error: 647 abort_creds(new); 648 return retval; 649 } 650 651 SYSCALL_DEFINE1(setuid, uid_t, uid) 652 { 653 return __sys_setuid(uid); 654 } 655 656 657 /* 658 * This function implements a generic ability to update ruid, euid, 659 * and suid. This allows you to implement the 4.4 compatible seteuid(). 660 */ 661 long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) 662 { 663 struct user_namespace *ns = current_user_ns(); 664 const struct cred *old; 665 struct cred *new; 666 int retval; 667 kuid_t kruid, keuid, ksuid; 668 bool ruid_new, euid_new, suid_new; 669 670 kruid = make_kuid(ns, ruid); 671 keuid = make_kuid(ns, euid); 672 ksuid = make_kuid(ns, suid); 673 674 if ((ruid != (uid_t) -1) && !uid_valid(kruid)) 675 return -EINVAL; 676 677 if ((euid != (uid_t) -1) && !uid_valid(keuid)) 678 return -EINVAL; 679 680 if ((suid != (uid_t) -1) && !uid_valid(ksuid)) 681 return -EINVAL; 682 683 old = current_cred(); 684 685 /* check for no-op */ 686 if ((ruid == (uid_t) -1 || uid_eq(kruid, old->uid)) && 687 (euid == (uid_t) -1 || (uid_eq(keuid, old->euid) && 688 uid_eq(keuid, old->fsuid))) && 689 (suid == (uid_t) -1 || uid_eq(ksuid, old->suid))) 690 return 0; 691 692 ruid_new = ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) && 693 !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid); 694 euid_new = euid != (uid_t) -1 && !uid_eq(keuid, old->uid) && 695 !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid); 696 suid_new = suid != (uid_t) -1 && !uid_eq(ksuid, old->uid) && 697 !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid); 698 if ((ruid_new || euid_new || suid_new) && 699 !ns_capable_setid(old->user_ns, CAP_SETUID)) 700 return -EPERM; 701 702 new = prepare_creds(); 703 if (!new) 704 return -ENOMEM; 705 706 if (ruid != (uid_t) -1) { 707 new->uid = kruid; 708 if (!uid_eq(kruid, old->uid)) { 709 retval = set_user(new); 710 if (retval < 0) 711 goto error; 712 } 713 } 714 if (euid != (uid_t) -1) 715 new->euid = keuid; 716 if (suid != (uid_t) -1) 717 new->suid = ksuid; 718 new->fsuid = new->euid; 719 720 retval = security_task_fix_setuid(new, old, LSM_SETID_RES); 721 if (retval < 0) 722 goto error; 723 724 retval = set_cred_ucounts(new); 725 if (retval < 0) 726 goto error; 727 728 flag_nproc_exceeded(new); 729 return commit_creds(new); 730 731 error: 732 abort_creds(new); 733 return retval; 734 } 735 736 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid) 737 { 738 return __sys_setresuid(ruid, euid, suid); 739 } 740 741 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp) 742 { 743 const struct cred *cred = current_cred(); 744 int retval; 745 uid_t ruid, euid, suid; 746 747 ruid = from_kuid_munged(cred->user_ns, cred->uid); 748 euid = from_kuid_munged(cred->user_ns, cred->euid); 749 suid = from_kuid_munged(cred->user_ns, cred->suid); 750 751 retval = put_user(ruid, ruidp); 752 if (!retval) { 753 retval = put_user(euid, euidp); 754 if (!retval) 755 return put_user(suid, suidp); 756 } 757 return retval; 758 } 759 760 /* 761 * Same as above, but for rgid, egid, sgid. 762 */ 763 long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid) 764 { 765 struct user_namespace *ns = current_user_ns(); 766 const struct cred *old; 767 struct cred *new; 768 int retval; 769 kgid_t krgid, kegid, ksgid; 770 bool rgid_new, egid_new, sgid_new; 771 772 krgid = make_kgid(ns, rgid); 773 kegid = make_kgid(ns, egid); 774 ksgid = make_kgid(ns, sgid); 775 776 if ((rgid != (gid_t) -1) && !gid_valid(krgid)) 777 return -EINVAL; 778 if ((egid != (gid_t) -1) && !gid_valid(kegid)) 779 return -EINVAL; 780 if ((sgid != (gid_t) -1) && !gid_valid(ksgid)) 781 return -EINVAL; 782 783 old = current_cred(); 784 785 /* check for no-op */ 786 if ((rgid == (gid_t) -1 || gid_eq(krgid, old->gid)) && 787 (egid == (gid_t) -1 || (gid_eq(kegid, old->egid) && 788 gid_eq(kegid, old->fsgid))) && 789 (sgid == (gid_t) -1 || gid_eq(ksgid, old->sgid))) 790 return 0; 791 792 rgid_new = rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) && 793 !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid); 794 egid_new = egid != (gid_t) -1 && !gid_eq(kegid, old->gid) && 795 !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid); 796 sgid_new = sgid != (gid_t) -1 && !gid_eq(ksgid, old->gid) && 797 !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid); 798 if ((rgid_new || egid_new || sgid_new) && 799 !ns_capable_setid(old->user_ns, CAP_SETGID)) 800 return -EPERM; 801 802 new = prepare_creds(); 803 if (!new) 804 return -ENOMEM; 805 806 if (rgid != (gid_t) -1) 807 new->gid = krgid; 808 if (egid != (gid_t) -1) 809 new->egid = kegid; 810 if (sgid != (gid_t) -1) 811 new->sgid = ksgid; 812 new->fsgid = new->egid; 813 814 retval = security_task_fix_setgid(new, old, LSM_SETID_RES); 815 if (retval < 0) 816 goto error; 817 818 return commit_creds(new); 819 820 error: 821 abort_creds(new); 822 return retval; 823 } 824 825 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid) 826 { 827 return __sys_setresgid(rgid, egid, sgid); 828 } 829 830 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp) 831 { 832 const struct cred *cred = current_cred(); 833 int retval; 834 gid_t rgid, egid, sgid; 835 836 rgid = from_kgid_munged(cred->user_ns, cred->gid); 837 egid = from_kgid_munged(cred->user_ns, cred->egid); 838 sgid = from_kgid_munged(cred->user_ns, cred->sgid); 839 840 retval = put_user(rgid, rgidp); 841 if (!retval) { 842 retval = put_user(egid, egidp); 843 if (!retval) 844 retval = put_user(sgid, sgidp); 845 } 846 847 return retval; 848 } 849 850 851 /* 852 * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This 853 * is used for "access()" and for the NFS daemon (letting nfsd stay at 854 * whatever uid it wants to). It normally shadows "euid", except when 855 * explicitly set by setfsuid() or for access.. 856 */ 857 long __sys_setfsuid(uid_t uid) 858 { 859 const struct cred *old; 860 struct cred *new; 861 uid_t old_fsuid; 862 kuid_t kuid; 863 864 old = current_cred(); 865 old_fsuid = from_kuid_munged(old->user_ns, old->fsuid); 866 867 kuid = make_kuid(old->user_ns, uid); 868 if (!uid_valid(kuid)) 869 return old_fsuid; 870 871 new = prepare_creds(); 872 if (!new) 873 return old_fsuid; 874 875 if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) || 876 uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) || 877 ns_capable_setid(old->user_ns, CAP_SETUID)) { 878 if (!uid_eq(kuid, old->fsuid)) { 879 new->fsuid = kuid; 880 if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0) 881 goto change_okay; 882 } 883 } 884 885 abort_creds(new); 886 return old_fsuid; 887 888 change_okay: 889 commit_creds(new); 890 return old_fsuid; 891 } 892 893 SYSCALL_DEFINE1(setfsuid, uid_t, uid) 894 { 895 return __sys_setfsuid(uid); 896 } 897 898 /* 899 * Samma på svenska.. 900 */ 901 long __sys_setfsgid(gid_t gid) 902 { 903 const struct cred *old; 904 struct cred *new; 905 gid_t old_fsgid; 906 kgid_t kgid; 907 908 old = current_cred(); 909 old_fsgid = from_kgid_munged(old->user_ns, old->fsgid); 910 911 kgid = make_kgid(old->user_ns, gid); 912 if (!gid_valid(kgid)) 913 return old_fsgid; 914 915 new = prepare_creds(); 916 if (!new) 917 return old_fsgid; 918 919 if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) || 920 gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) || 921 ns_capable_setid(old->user_ns, CAP_SETGID)) { 922 if (!gid_eq(kgid, old->fsgid)) { 923 new->fsgid = kgid; 924 if (security_task_fix_setgid(new,old,LSM_SETID_FS) == 0) 925 goto change_okay; 926 } 927 } 928 929 abort_creds(new); 930 return old_fsgid; 931 932 change_okay: 933 commit_creds(new); 934 return old_fsgid; 935 } 936 937 SYSCALL_DEFINE1(setfsgid, gid_t, gid) 938 { 939 return __sys_setfsgid(gid); 940 } 941 #endif /* CONFIG_MULTIUSER */ 942 943 /** 944 * sys_getpid - return the thread group id of the current process 945 * 946 * Note, despite the name, this returns the tgid not the pid. The tgid and 947 * the pid are identical unless CLONE_THREAD was specified on clone() in 948 * which case the tgid is the same in all threads of the same group. 949 * 950 * This is SMP safe as current->tgid does not change. 951 */ 952 SYSCALL_DEFINE0(getpid) 953 { 954 return task_tgid_vnr(current); 955 } 956 957 /* Thread ID - the internal kernel "pid" */ 958 SYSCALL_DEFINE0(gettid) 959 { 960 return task_pid_vnr(current); 961 } 962 963 /* 964 * Accessing ->real_parent is not SMP-safe, it could 965 * change from under us. However, we can use a stale 966 * value of ->real_parent under rcu_read_lock(), see 967 * release_task()->call_rcu(delayed_put_task_struct). 968 */ 969 SYSCALL_DEFINE0(getppid) 970 { 971 int pid; 972 973 rcu_read_lock(); 974 pid = task_tgid_vnr(rcu_dereference(current->real_parent)); 975 rcu_read_unlock(); 976 977 return pid; 978 } 979 980 SYSCALL_DEFINE0(getuid) 981 { 982 /* Only we change this so SMP safe */ 983 return from_kuid_munged(current_user_ns(), current_uid()); 984 } 985 986 SYSCALL_DEFINE0(geteuid) 987 { 988 /* Only we change this so SMP safe */ 989 return from_kuid_munged(current_user_ns(), current_euid()); 990 } 991 992 SYSCALL_DEFINE0(getgid) 993 { 994 /* Only we change this so SMP safe */ 995 return from_kgid_munged(current_user_ns(), current_gid()); 996 } 997 998 SYSCALL_DEFINE0(getegid) 999 { 1000 /* Only we change this so SMP safe */ 1001 return from_kgid_munged(current_user_ns(), current_egid()); 1002 } 1003 1004 static void do_sys_times(struct tms *tms) 1005 { 1006 u64 tgutime, tgstime, cutime, cstime; 1007 1008 thread_group_cputime_adjusted(current, &tgutime, &tgstime); 1009 cutime = current->signal->cutime; 1010 cstime = current->signal->cstime; 1011 tms->tms_utime = nsec_to_clock_t(tgutime); 1012 tms->tms_stime = nsec_to_clock_t(tgstime); 1013 tms->tms_cutime = nsec_to_clock_t(cutime); 1014 tms->tms_cstime = nsec_to_clock_t(cstime); 1015 } 1016 1017 SYSCALL_DEFINE1(times, struct tms __user *, tbuf) 1018 { 1019 if (tbuf) { 1020 struct tms tmp; 1021 1022 do_sys_times(&tmp); 1023 if (copy_to_user(tbuf, &tmp, sizeof(struct tms))) 1024 return -EFAULT; 1025 } 1026 force_successful_syscall_return(); 1027 return (long) jiffies_64_to_clock_t(get_jiffies_64()); 1028 } 1029 1030 #ifdef CONFIG_COMPAT 1031 static compat_clock_t clock_t_to_compat_clock_t(clock_t x) 1032 { 1033 return compat_jiffies_to_clock_t(clock_t_to_jiffies(x)); 1034 } 1035 1036 COMPAT_SYSCALL_DEFINE1(times, struct compat_tms __user *, tbuf) 1037 { 1038 if (tbuf) { 1039 struct tms tms; 1040 struct compat_tms tmp; 1041 1042 do_sys_times(&tms); 1043 /* Convert our struct tms to the compat version. */ 1044 tmp.tms_utime = clock_t_to_compat_clock_t(tms.tms_utime); 1045 tmp.tms_stime = clock_t_to_compat_clock_t(tms.tms_stime); 1046 tmp.tms_cutime = clock_t_to_compat_clock_t(tms.tms_cutime); 1047 tmp.tms_cstime = clock_t_to_compat_clock_t(tms.tms_cstime); 1048 if (copy_to_user(tbuf, &tmp, sizeof(tmp))) 1049 return -EFAULT; 1050 } 1051 force_successful_syscall_return(); 1052 return compat_jiffies_to_clock_t(jiffies); 1053 } 1054 #endif 1055 1056 /* 1057 * This needs some heavy checking ... 1058 * I just haven't the stomach for it. I also don't fully 1059 * understand sessions/pgrp etc. Let somebody who does explain it. 1060 * 1061 * OK, I think I have the protection semantics right.... this is really 1062 * only important on a multi-user system anyway, to make sure one user 1063 * can't send a signal to a process owned by another. -TYT, 12/12/91 1064 * 1065 * !PF_FORKNOEXEC check to conform completely to POSIX. 1066 */ 1067 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid) 1068 { 1069 struct task_struct *p; 1070 struct task_struct *group_leader = current->group_leader; 1071 struct pid *pgrp; 1072 int err; 1073 1074 if (!pid) 1075 pid = task_pid_vnr(group_leader); 1076 if (!pgid) 1077 pgid = pid; 1078 if (pgid < 0) 1079 return -EINVAL; 1080 rcu_read_lock(); 1081 1082 /* From this point forward we keep holding onto the tasklist lock 1083 * so that our parent does not change from under us. -DaveM 1084 */ 1085 write_lock_irq(&tasklist_lock); 1086 1087 err = -ESRCH; 1088 p = find_task_by_vpid(pid); 1089 if (!p) 1090 goto out; 1091 1092 err = -EINVAL; 1093 if (!thread_group_leader(p)) 1094 goto out; 1095 1096 if (same_thread_group(p->real_parent, group_leader)) { 1097 err = -EPERM; 1098 if (task_session(p) != task_session(group_leader)) 1099 goto out; 1100 err = -EACCES; 1101 if (!(p->flags & PF_FORKNOEXEC)) 1102 goto out; 1103 } else { 1104 err = -ESRCH; 1105 if (p != group_leader) 1106 goto out; 1107 } 1108 1109 err = -EPERM; 1110 if (p->signal->leader) 1111 goto out; 1112 1113 pgrp = task_pid(p); 1114 if (pgid != pid) { 1115 struct task_struct *g; 1116 1117 pgrp = find_vpid(pgid); 1118 g = pid_task(pgrp, PIDTYPE_PGID); 1119 if (!g || task_session(g) != task_session(group_leader)) 1120 goto out; 1121 } 1122 1123 err = security_task_setpgid(p, pgid); 1124 if (err) 1125 goto out; 1126 1127 if (task_pgrp(p) != pgrp) 1128 change_pid(p, PIDTYPE_PGID, pgrp); 1129 1130 err = 0; 1131 out: 1132 /* All paths lead to here, thus we are safe. -DaveM */ 1133 write_unlock_irq(&tasklist_lock); 1134 rcu_read_unlock(); 1135 return err; 1136 } 1137 1138 static int do_getpgid(pid_t pid) 1139 { 1140 struct task_struct *p; 1141 struct pid *grp; 1142 int retval; 1143 1144 rcu_read_lock(); 1145 if (!pid) 1146 grp = task_pgrp(current); 1147 else { 1148 retval = -ESRCH; 1149 p = find_task_by_vpid(pid); 1150 if (!p) 1151 goto out; 1152 grp = task_pgrp(p); 1153 if (!grp) 1154 goto out; 1155 1156 retval = security_task_getpgid(p); 1157 if (retval) 1158 goto out; 1159 } 1160 retval = pid_vnr(grp); 1161 out: 1162 rcu_read_unlock(); 1163 return retval; 1164 } 1165 1166 SYSCALL_DEFINE1(getpgid, pid_t, pid) 1167 { 1168 return do_getpgid(pid); 1169 } 1170 1171 #ifdef __ARCH_WANT_SYS_GETPGRP 1172 1173 SYSCALL_DEFINE0(getpgrp) 1174 { 1175 return do_getpgid(0); 1176 } 1177 1178 #endif 1179 1180 SYSCALL_DEFINE1(getsid, pid_t, pid) 1181 { 1182 struct task_struct *p; 1183 struct pid *sid; 1184 int retval; 1185 1186 rcu_read_lock(); 1187 if (!pid) 1188 sid = task_session(current); 1189 else { 1190 retval = -ESRCH; 1191 p = find_task_by_vpid(pid); 1192 if (!p) 1193 goto out; 1194 sid = task_session(p); 1195 if (!sid) 1196 goto out; 1197 1198 retval = security_task_getsid(p); 1199 if (retval) 1200 goto out; 1201 } 1202 retval = pid_vnr(sid); 1203 out: 1204 rcu_read_unlock(); 1205 return retval; 1206 } 1207 1208 static void set_special_pids(struct pid *pid) 1209 { 1210 struct task_struct *curr = current->group_leader; 1211 1212 if (task_session(curr) != pid) 1213 change_pid(curr, PIDTYPE_SID, pid); 1214 1215 if (task_pgrp(curr) != pid) 1216 change_pid(curr, PIDTYPE_PGID, pid); 1217 } 1218 1219 int ksys_setsid(void) 1220 { 1221 struct task_struct *group_leader = current->group_leader; 1222 struct pid *sid = task_pid(group_leader); 1223 pid_t session = pid_vnr(sid); 1224 int err = -EPERM; 1225 1226 write_lock_irq(&tasklist_lock); 1227 /* Fail if I am already a session leader */ 1228 if (group_leader->signal->leader) 1229 goto out; 1230 1231 /* Fail if a process group id already exists that equals the 1232 * proposed session id. 1233 */ 1234 if (pid_task(sid, PIDTYPE_PGID)) 1235 goto out; 1236 1237 group_leader->signal->leader = 1; 1238 set_special_pids(sid); 1239 1240 proc_clear_tty(group_leader); 1241 1242 err = session; 1243 out: 1244 write_unlock_irq(&tasklist_lock); 1245 if (err > 0) { 1246 proc_sid_connector(group_leader); 1247 sched_autogroup_create_attach(group_leader); 1248 } 1249 return err; 1250 } 1251 1252 SYSCALL_DEFINE0(setsid) 1253 { 1254 return ksys_setsid(); 1255 } 1256 1257 DECLARE_RWSEM(uts_sem); 1258 1259 #ifdef COMPAT_UTS_MACHINE 1260 #define override_architecture(name) \ 1261 (personality(current->personality) == PER_LINUX32 && \ 1262 copy_to_user(name->machine, COMPAT_UTS_MACHINE, \ 1263 sizeof(COMPAT_UTS_MACHINE))) 1264 #else 1265 #define override_architecture(name) 0 1266 #endif 1267 1268 /* 1269 * Work around broken programs that cannot handle "Linux 3.0". 1270 * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40 1271 * And we map 4.x and later versions to 2.6.60+x, so 4.0/5.0/6.0/... would be 1272 * 2.6.60. 1273 */ 1274 static int override_release(char __user *release, size_t len) 1275 { 1276 int ret = 0; 1277 1278 if (current->personality & UNAME26) { 1279 const char *rest = UTS_RELEASE; 1280 char buf[65] = { 0 }; 1281 int ndots = 0; 1282 unsigned v; 1283 size_t copy; 1284 1285 while (*rest) { 1286 if (*rest == '.' && ++ndots >= 3) 1287 break; 1288 if (!isdigit(*rest) && *rest != '.') 1289 break; 1290 rest++; 1291 } 1292 v = LINUX_VERSION_PATCHLEVEL + 60; 1293 copy = clamp_t(size_t, len, 1, sizeof(buf)); 1294 copy = scnprintf(buf, copy, "2.6.%u%s", v, rest); 1295 ret = copy_to_user(release, buf, copy + 1); 1296 } 1297 return ret; 1298 } 1299 1300 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name) 1301 { 1302 struct new_utsname tmp; 1303 1304 down_read(&uts_sem); 1305 memcpy(&tmp, utsname(), sizeof(tmp)); 1306 up_read(&uts_sem); 1307 if (copy_to_user(name, &tmp, sizeof(tmp))) 1308 return -EFAULT; 1309 1310 if (override_release(name->release, sizeof(name->release))) 1311 return -EFAULT; 1312 if (override_architecture(name)) 1313 return -EFAULT; 1314 return 0; 1315 } 1316 1317 #ifdef __ARCH_WANT_SYS_OLD_UNAME 1318 /* 1319 * Old cruft 1320 */ 1321 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name) 1322 { 1323 struct old_utsname tmp; 1324 1325 if (!name) 1326 return -EFAULT; 1327 1328 down_read(&uts_sem); 1329 memcpy(&tmp, utsname(), sizeof(tmp)); 1330 up_read(&uts_sem); 1331 if (copy_to_user(name, &tmp, sizeof(tmp))) 1332 return -EFAULT; 1333 1334 if (override_release(name->release, sizeof(name->release))) 1335 return -EFAULT; 1336 if (override_architecture(name)) 1337 return -EFAULT; 1338 return 0; 1339 } 1340 1341 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name) 1342 { 1343 struct oldold_utsname tmp; 1344 1345 if (!name) 1346 return -EFAULT; 1347 1348 memset(&tmp, 0, sizeof(tmp)); 1349 1350 down_read(&uts_sem); 1351 memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN); 1352 memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN); 1353 memcpy(&tmp.release, &utsname()->release, __OLD_UTS_LEN); 1354 memcpy(&tmp.version, &utsname()->version, __OLD_UTS_LEN); 1355 memcpy(&tmp.machine, &utsname()->machine, __OLD_UTS_LEN); 1356 up_read(&uts_sem); 1357 if (copy_to_user(name, &tmp, sizeof(tmp))) 1358 return -EFAULT; 1359 1360 if (override_architecture(name)) 1361 return -EFAULT; 1362 if (override_release(name->release, sizeof(name->release))) 1363 return -EFAULT; 1364 return 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 errno = -EFAULT; 1379 if (!copy_from_user(tmp, name, len)) { 1380 struct new_utsname *u; 1381 1382 add_device_randomness(tmp, len); 1383 down_write(&uts_sem); 1384 u = utsname(); 1385 memcpy(u->nodename, tmp, len); 1386 memset(u->nodename + len, 0, sizeof(u->nodename) - len); 1387 errno = 0; 1388 uts_proc_notify(UTS_PROC_HOSTNAME); 1389 up_write(&uts_sem); 1390 } 1391 return errno; 1392 } 1393 1394 #ifdef __ARCH_WANT_SYS_GETHOSTNAME 1395 1396 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len) 1397 { 1398 int i; 1399 struct new_utsname *u; 1400 char tmp[__NEW_UTS_LEN + 1]; 1401 1402 if (len < 0) 1403 return -EINVAL; 1404 down_read(&uts_sem); 1405 u = utsname(); 1406 i = 1 + strlen(u->nodename); 1407 if (i > len) 1408 i = len; 1409 memcpy(tmp, u->nodename, i); 1410 up_read(&uts_sem); 1411 if (copy_to_user(name, tmp, i)) 1412 return -EFAULT; 1413 return 0; 1414 } 1415 1416 #endif 1417 1418 /* 1419 * Only setdomainname; getdomainname can be implemented by calling 1420 * uname() 1421 */ 1422 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len) 1423 { 1424 int errno; 1425 char tmp[__NEW_UTS_LEN]; 1426 1427 if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN)) 1428 return -EPERM; 1429 if (len < 0 || len > __NEW_UTS_LEN) 1430 return -EINVAL; 1431 1432 errno = -EFAULT; 1433 if (!copy_from_user(tmp, name, len)) { 1434 struct new_utsname *u; 1435 1436 add_device_randomness(tmp, len); 1437 down_write(&uts_sem); 1438 u = utsname(); 1439 memcpy(u->domainname, tmp, len); 1440 memset(u->domainname + len, 0, sizeof(u->domainname) - len); 1441 errno = 0; 1442 uts_proc_notify(UTS_PROC_DOMAINNAME); 1443 up_write(&uts_sem); 1444 } 1445 return errno; 1446 } 1447 1448 /* make sure you are allowed to change @tsk limits before calling this */ 1449 static int do_prlimit(struct task_struct *tsk, unsigned int resource, 1450 struct rlimit *new_rlim, struct rlimit *old_rlim) 1451 { 1452 struct rlimit *rlim; 1453 int retval = 0; 1454 1455 if (resource >= RLIM_NLIMITS) 1456 return -EINVAL; 1457 resource = array_index_nospec(resource, RLIM_NLIMITS); 1458 1459 if (new_rlim) { 1460 if (new_rlim->rlim_cur > new_rlim->rlim_max) 1461 return -EINVAL; 1462 if (resource == RLIMIT_NOFILE && 1463 new_rlim->rlim_max > sysctl_nr_open) 1464 return -EPERM; 1465 } 1466 1467 /* Holding a refcount on tsk protects tsk->signal from disappearing. */ 1468 rlim = tsk->signal->rlim + resource; 1469 task_lock(tsk->group_leader); 1470 if (new_rlim) { 1471 /* 1472 * Keep the capable check against init_user_ns until cgroups can 1473 * contain all limits. 1474 */ 1475 if (new_rlim->rlim_max > rlim->rlim_max && 1476 !capable(CAP_SYS_RESOURCE)) 1477 retval = -EPERM; 1478 if (!retval) 1479 retval = security_task_setrlimit(tsk, resource, new_rlim); 1480 } 1481 if (!retval) { 1482 if (old_rlim) 1483 *old_rlim = *rlim; 1484 if (new_rlim) 1485 *rlim = *new_rlim; 1486 } 1487 task_unlock(tsk->group_leader); 1488 1489 /* 1490 * RLIMIT_CPU handling. Arm the posix CPU timer if the limit is not 1491 * infinite. In case of RLIM_INFINITY the posix CPU timer code 1492 * ignores the rlimit. 1493 */ 1494 if (!retval && new_rlim && resource == RLIMIT_CPU && 1495 new_rlim->rlim_cur != RLIM_INFINITY && 1496 IS_ENABLED(CONFIG_POSIX_TIMERS)) { 1497 /* 1498 * update_rlimit_cpu can fail if the task is exiting, but there 1499 * may be other tasks in the thread group that are not exiting, 1500 * and they need their cpu timers adjusted. 1501 * 1502 * The group_leader is the last task to be released, so if we 1503 * cannot update_rlimit_cpu on it, then the entire process is 1504 * exiting and we do not need to update at all. 1505 */ 1506 update_rlimit_cpu(tsk->group_leader, new_rlim->rlim_cur); 1507 } 1508 1509 return retval; 1510 } 1511 1512 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim) 1513 { 1514 struct rlimit value; 1515 int ret; 1516 1517 ret = do_prlimit(current, resource, NULL, &value); 1518 if (!ret) 1519 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0; 1520 1521 return ret; 1522 } 1523 1524 #ifdef CONFIG_COMPAT 1525 1526 COMPAT_SYSCALL_DEFINE2(setrlimit, unsigned int, resource, 1527 struct compat_rlimit __user *, rlim) 1528 { 1529 struct rlimit r; 1530 struct compat_rlimit r32; 1531 1532 if (copy_from_user(&r32, rlim, sizeof(struct compat_rlimit))) 1533 return -EFAULT; 1534 1535 if (r32.rlim_cur == COMPAT_RLIM_INFINITY) 1536 r.rlim_cur = RLIM_INFINITY; 1537 else 1538 r.rlim_cur = r32.rlim_cur; 1539 if (r32.rlim_max == COMPAT_RLIM_INFINITY) 1540 r.rlim_max = RLIM_INFINITY; 1541 else 1542 r.rlim_max = r32.rlim_max; 1543 return do_prlimit(current, resource, &r, NULL); 1544 } 1545 1546 COMPAT_SYSCALL_DEFINE2(getrlimit, unsigned int, resource, 1547 struct compat_rlimit __user *, rlim) 1548 { 1549 struct rlimit r; 1550 int ret; 1551 1552 ret = do_prlimit(current, resource, NULL, &r); 1553 if (!ret) { 1554 struct compat_rlimit r32; 1555 if (r.rlim_cur > COMPAT_RLIM_INFINITY) 1556 r32.rlim_cur = COMPAT_RLIM_INFINITY; 1557 else 1558 r32.rlim_cur = r.rlim_cur; 1559 if (r.rlim_max > COMPAT_RLIM_INFINITY) 1560 r32.rlim_max = COMPAT_RLIM_INFINITY; 1561 else 1562 r32.rlim_max = r.rlim_max; 1563 1564 if (copy_to_user(rlim, &r32, sizeof(struct compat_rlimit))) 1565 return -EFAULT; 1566 } 1567 return ret; 1568 } 1569 1570 #endif 1571 1572 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT 1573 1574 /* 1575 * Back compatibility for getrlimit. Needed for some apps. 1576 */ 1577 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource, 1578 struct rlimit __user *, rlim) 1579 { 1580 struct rlimit x; 1581 if (resource >= RLIM_NLIMITS) 1582 return -EINVAL; 1583 1584 resource = array_index_nospec(resource, RLIM_NLIMITS); 1585 task_lock(current->group_leader); 1586 x = current->signal->rlim[resource]; 1587 task_unlock(current->group_leader); 1588 if (x.rlim_cur > 0x7FFFFFFF) 1589 x.rlim_cur = 0x7FFFFFFF; 1590 if (x.rlim_max > 0x7FFFFFFF) 1591 x.rlim_max = 0x7FFFFFFF; 1592 return copy_to_user(rlim, &x, sizeof(x)) ? -EFAULT : 0; 1593 } 1594 1595 #ifdef CONFIG_COMPAT 1596 COMPAT_SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource, 1597 struct compat_rlimit __user *, rlim) 1598 { 1599 struct rlimit r; 1600 1601 if (resource >= RLIM_NLIMITS) 1602 return -EINVAL; 1603 1604 resource = array_index_nospec(resource, RLIM_NLIMITS); 1605 task_lock(current->group_leader); 1606 r = current->signal->rlim[resource]; 1607 task_unlock(current->group_leader); 1608 if (r.rlim_cur > 0x7FFFFFFF) 1609 r.rlim_cur = 0x7FFFFFFF; 1610 if (r.rlim_max > 0x7FFFFFFF) 1611 r.rlim_max = 0x7FFFFFFF; 1612 1613 if (put_user(r.rlim_cur, &rlim->rlim_cur) || 1614 put_user(r.rlim_max, &rlim->rlim_max)) 1615 return -EFAULT; 1616 return 0; 1617 } 1618 #endif 1619 1620 #endif 1621 1622 static inline bool rlim64_is_infinity(__u64 rlim64) 1623 { 1624 #if BITS_PER_LONG < 64 1625 return rlim64 >= ULONG_MAX; 1626 #else 1627 return rlim64 == RLIM64_INFINITY; 1628 #endif 1629 } 1630 1631 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64) 1632 { 1633 if (rlim->rlim_cur == RLIM_INFINITY) 1634 rlim64->rlim_cur = RLIM64_INFINITY; 1635 else 1636 rlim64->rlim_cur = rlim->rlim_cur; 1637 if (rlim->rlim_max == RLIM_INFINITY) 1638 rlim64->rlim_max = RLIM64_INFINITY; 1639 else 1640 rlim64->rlim_max = rlim->rlim_max; 1641 } 1642 1643 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim) 1644 { 1645 if (rlim64_is_infinity(rlim64->rlim_cur)) 1646 rlim->rlim_cur = RLIM_INFINITY; 1647 else 1648 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur; 1649 if (rlim64_is_infinity(rlim64->rlim_max)) 1650 rlim->rlim_max = RLIM_INFINITY; 1651 else 1652 rlim->rlim_max = (unsigned long)rlim64->rlim_max; 1653 } 1654 1655 /* rcu lock must be held */ 1656 static int check_prlimit_permission(struct task_struct *task, 1657 unsigned int flags) 1658 { 1659 const struct cred *cred = current_cred(), *tcred; 1660 bool id_match; 1661 1662 if (current == task) 1663 return 0; 1664 1665 tcred = __task_cred(task); 1666 id_match = (uid_eq(cred->uid, tcred->euid) && 1667 uid_eq(cred->uid, tcred->suid) && 1668 uid_eq(cred->uid, tcred->uid) && 1669 gid_eq(cred->gid, tcred->egid) && 1670 gid_eq(cred->gid, tcred->sgid) && 1671 gid_eq(cred->gid, tcred->gid)); 1672 if (!id_match && !ns_capable(tcred->user_ns, CAP_SYS_RESOURCE)) 1673 return -EPERM; 1674 1675 return security_task_prlimit(cred, tcred, flags); 1676 } 1677 1678 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource, 1679 const struct rlimit64 __user *, new_rlim, 1680 struct rlimit64 __user *, old_rlim) 1681 { 1682 struct rlimit64 old64, new64; 1683 struct rlimit old, new; 1684 struct task_struct *tsk; 1685 unsigned int checkflags = 0; 1686 int ret; 1687 1688 if (old_rlim) 1689 checkflags |= LSM_PRLIMIT_READ; 1690 1691 if (new_rlim) { 1692 if (copy_from_user(&new64, new_rlim, sizeof(new64))) 1693 return -EFAULT; 1694 rlim64_to_rlim(&new64, &new); 1695 checkflags |= LSM_PRLIMIT_WRITE; 1696 } 1697 1698 rcu_read_lock(); 1699 tsk = pid ? find_task_by_vpid(pid) : current; 1700 if (!tsk) { 1701 rcu_read_unlock(); 1702 return -ESRCH; 1703 } 1704 ret = check_prlimit_permission(tsk, checkflags); 1705 if (ret) { 1706 rcu_read_unlock(); 1707 return ret; 1708 } 1709 get_task_struct(tsk); 1710 rcu_read_unlock(); 1711 1712 ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL, 1713 old_rlim ? &old : NULL); 1714 1715 if (!ret && old_rlim) { 1716 rlim_to_rlim64(&old, &old64); 1717 if (copy_to_user(old_rlim, &old64, sizeof(old64))) 1718 ret = -EFAULT; 1719 } 1720 1721 put_task_struct(tsk); 1722 return ret; 1723 } 1724 1725 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim) 1726 { 1727 struct rlimit new_rlim; 1728 1729 if (copy_from_user(&new_rlim, rlim, sizeof(*rlim))) 1730 return -EFAULT; 1731 return do_prlimit(current, resource, &new_rlim, NULL); 1732 } 1733 1734 /* 1735 * It would make sense to put struct rusage in the task_struct, 1736 * except that would make the task_struct be *really big*. After 1737 * task_struct gets moved into malloc'ed memory, it would 1738 * make sense to do this. It will make moving the rest of the information 1739 * a lot simpler! (Which we're not doing right now because we're not 1740 * measuring them yet). 1741 * 1742 * When sampling multiple threads for RUSAGE_SELF, under SMP we might have 1743 * races with threads incrementing their own counters. But since word 1744 * reads are atomic, we either get new values or old values and we don't 1745 * care which for the sums. We always take the siglock to protect reading 1746 * the c* fields from p->signal from races with exit.c updating those 1747 * fields when reaping, so a sample either gets all the additions of a 1748 * given child after it's reaped, or none so this sample is before reaping. 1749 * 1750 * Locking: 1751 * We need to take the siglock for CHILDEREN, SELF and BOTH 1752 * for the cases current multithreaded, non-current single threaded 1753 * non-current multithreaded. Thread traversal is now safe with 1754 * the siglock held. 1755 * Strictly speaking, we donot need to take the siglock if we are current and 1756 * single threaded, as no one else can take our signal_struct away, no one 1757 * else can reap the children to update signal->c* counters, and no one else 1758 * can race with the signal-> fields. If we do not take any lock, the 1759 * signal-> fields could be read out of order while another thread was just 1760 * exiting. So we should place a read memory barrier when we avoid the lock. 1761 * On the writer side, write memory barrier is implied in __exit_signal 1762 * as __exit_signal releases the siglock spinlock after updating the signal-> 1763 * fields. But we don't do this yet to keep things simple. 1764 * 1765 */ 1766 1767 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r) 1768 { 1769 r->ru_nvcsw += t->nvcsw; 1770 r->ru_nivcsw += t->nivcsw; 1771 r->ru_minflt += t->min_flt; 1772 r->ru_majflt += t->maj_flt; 1773 r->ru_inblock += task_io_get_inblock(t); 1774 r->ru_oublock += task_io_get_oublock(t); 1775 } 1776 1777 void getrusage(struct task_struct *p, int who, struct rusage *r) 1778 { 1779 struct task_struct *t; 1780 unsigned long flags; 1781 u64 tgutime, tgstime, utime, stime; 1782 unsigned long maxrss = 0; 1783 1784 memset((char *)r, 0, sizeof (*r)); 1785 utime = stime = 0; 1786 1787 if (who == RUSAGE_THREAD) { 1788 task_cputime_adjusted(current, &utime, &stime); 1789 accumulate_thread_rusage(p, r); 1790 maxrss = p->signal->maxrss; 1791 goto out; 1792 } 1793 1794 if (!lock_task_sighand(p, &flags)) 1795 return; 1796 1797 switch (who) { 1798 case RUSAGE_BOTH: 1799 case RUSAGE_CHILDREN: 1800 utime = p->signal->cutime; 1801 stime = p->signal->cstime; 1802 r->ru_nvcsw = p->signal->cnvcsw; 1803 r->ru_nivcsw = p->signal->cnivcsw; 1804 r->ru_minflt = p->signal->cmin_flt; 1805 r->ru_majflt = p->signal->cmaj_flt; 1806 r->ru_inblock = p->signal->cinblock; 1807 r->ru_oublock = p->signal->coublock; 1808 maxrss = p->signal->cmaxrss; 1809 1810 if (who == RUSAGE_CHILDREN) 1811 break; 1812 fallthrough; 1813 1814 case RUSAGE_SELF: 1815 thread_group_cputime_adjusted(p, &tgutime, &tgstime); 1816 utime += tgutime; 1817 stime += tgstime; 1818 r->ru_nvcsw += p->signal->nvcsw; 1819 r->ru_nivcsw += p->signal->nivcsw; 1820 r->ru_minflt += p->signal->min_flt; 1821 r->ru_majflt += p->signal->maj_flt; 1822 r->ru_inblock += p->signal->inblock; 1823 r->ru_oublock += p->signal->oublock; 1824 if (maxrss < p->signal->maxrss) 1825 maxrss = p->signal->maxrss; 1826 t = p; 1827 do { 1828 accumulate_thread_rusage(t, r); 1829 } while_each_thread(p, t); 1830 break; 1831 1832 default: 1833 BUG(); 1834 } 1835 unlock_task_sighand(p, &flags); 1836 1837 out: 1838 r->ru_utime = ns_to_kernel_old_timeval(utime); 1839 r->ru_stime = ns_to_kernel_old_timeval(stime); 1840 1841 if (who != RUSAGE_CHILDREN) { 1842 struct mm_struct *mm = get_task_mm(p); 1843 1844 if (mm) { 1845 setmax_mm_hiwater_rss(&maxrss, mm); 1846 mmput(mm); 1847 } 1848 } 1849 r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */ 1850 } 1851 1852 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru) 1853 { 1854 struct rusage r; 1855 1856 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN && 1857 who != RUSAGE_THREAD) 1858 return -EINVAL; 1859 1860 getrusage(current, who, &r); 1861 return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0; 1862 } 1863 1864 #ifdef CONFIG_COMPAT 1865 COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru) 1866 { 1867 struct rusage r; 1868 1869 if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN && 1870 who != RUSAGE_THREAD) 1871 return -EINVAL; 1872 1873 getrusage(current, who, &r); 1874 return put_compat_rusage(&r, ru); 1875 } 1876 #endif 1877 1878 SYSCALL_DEFINE1(umask, int, mask) 1879 { 1880 mask = xchg(¤t->fs->umask, mask & S_IRWXUGO); 1881 return mask; 1882 } 1883 1884 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) 1885 { 1886 struct fd exe; 1887 struct inode *inode; 1888 int err; 1889 1890 exe = fdget(fd); 1891 if (!exe.file) 1892 return -EBADF; 1893 1894 inode = file_inode(exe.file); 1895 1896 /* 1897 * Because the original mm->exe_file points to executable file, make 1898 * sure that this one is executable as well, to avoid breaking an 1899 * overall picture. 1900 */ 1901 err = -EACCES; 1902 if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path)) 1903 goto exit; 1904 1905 err = file_permission(exe.file, MAY_EXEC); 1906 if (err) 1907 goto exit; 1908 1909 err = replace_mm_exe_file(mm, exe.file); 1910 exit: 1911 fdput(exe); 1912 return err; 1913 } 1914 1915 /* 1916 * Check arithmetic relations of passed addresses. 1917 * 1918 * WARNING: we don't require any capability here so be very careful 1919 * in what is allowed for modification from userspace. 1920 */ 1921 static int validate_prctl_map_addr(struct prctl_mm_map *prctl_map) 1922 { 1923 unsigned long mmap_max_addr = TASK_SIZE; 1924 int error = -EINVAL, i; 1925 1926 static const unsigned char offsets[] = { 1927 offsetof(struct prctl_mm_map, start_code), 1928 offsetof(struct prctl_mm_map, end_code), 1929 offsetof(struct prctl_mm_map, start_data), 1930 offsetof(struct prctl_mm_map, end_data), 1931 offsetof(struct prctl_mm_map, start_brk), 1932 offsetof(struct prctl_mm_map, brk), 1933 offsetof(struct prctl_mm_map, start_stack), 1934 offsetof(struct prctl_mm_map, arg_start), 1935 offsetof(struct prctl_mm_map, arg_end), 1936 offsetof(struct prctl_mm_map, env_start), 1937 offsetof(struct prctl_mm_map, env_end), 1938 }; 1939 1940 /* 1941 * Make sure the members are not somewhere outside 1942 * of allowed address space. 1943 */ 1944 for (i = 0; i < ARRAY_SIZE(offsets); i++) { 1945 u64 val = *(u64 *)((char *)prctl_map + offsets[i]); 1946 1947 if ((unsigned long)val >= mmap_max_addr || 1948 (unsigned long)val < mmap_min_addr) 1949 goto out; 1950 } 1951 1952 /* 1953 * Make sure the pairs are ordered. 1954 */ 1955 #define __prctl_check_order(__m1, __op, __m2) \ 1956 ((unsigned long)prctl_map->__m1 __op \ 1957 (unsigned long)prctl_map->__m2) ? 0 : -EINVAL 1958 error = __prctl_check_order(start_code, <, end_code); 1959 error |= __prctl_check_order(start_data,<=, end_data); 1960 error |= __prctl_check_order(start_brk, <=, brk); 1961 error |= __prctl_check_order(arg_start, <=, arg_end); 1962 error |= __prctl_check_order(env_start, <=, env_end); 1963 if (error) 1964 goto out; 1965 #undef __prctl_check_order 1966 1967 error = -EINVAL; 1968 1969 /* 1970 * Neither we should allow to override limits if they set. 1971 */ 1972 if (check_data_rlimit(rlimit(RLIMIT_DATA), prctl_map->brk, 1973 prctl_map->start_brk, prctl_map->end_data, 1974 prctl_map->start_data)) 1975 goto out; 1976 1977 error = 0; 1978 out: 1979 return error; 1980 } 1981 1982 #ifdef CONFIG_CHECKPOINT_RESTORE 1983 static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size) 1984 { 1985 struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, }; 1986 unsigned long user_auxv[AT_VECTOR_SIZE]; 1987 struct mm_struct *mm = current->mm; 1988 int error; 1989 1990 BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv)); 1991 BUILD_BUG_ON(sizeof(struct prctl_mm_map) > 256); 1992 1993 if (opt == PR_SET_MM_MAP_SIZE) 1994 return put_user((unsigned int)sizeof(prctl_map), 1995 (unsigned int __user *)addr); 1996 1997 if (data_size != sizeof(prctl_map)) 1998 return -EINVAL; 1999 2000 if (copy_from_user(&prctl_map, addr, sizeof(prctl_map))) 2001 return -EFAULT; 2002 2003 error = validate_prctl_map_addr(&prctl_map); 2004 if (error) 2005 return error; 2006 2007 if (prctl_map.auxv_size) { 2008 /* 2009 * Someone is trying to cheat the auxv vector. 2010 */ 2011 if (!prctl_map.auxv || 2012 prctl_map.auxv_size > sizeof(mm->saved_auxv)) 2013 return -EINVAL; 2014 2015 memset(user_auxv, 0, sizeof(user_auxv)); 2016 if (copy_from_user(user_auxv, 2017 (const void __user *)prctl_map.auxv, 2018 prctl_map.auxv_size)) 2019 return -EFAULT; 2020 2021 /* Last entry must be AT_NULL as specification requires */ 2022 user_auxv[AT_VECTOR_SIZE - 2] = AT_NULL; 2023 user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL; 2024 } 2025 2026 if (prctl_map.exe_fd != (u32)-1) { 2027 /* 2028 * Check if the current user is checkpoint/restore capable. 2029 * At the time of this writing, it checks for CAP_SYS_ADMIN 2030 * or CAP_CHECKPOINT_RESTORE. 2031 * Note that a user with access to ptrace can masquerade an 2032 * arbitrary program as any executable, even setuid ones. 2033 * This may have implications in the tomoyo subsystem. 2034 */ 2035 if (!checkpoint_restore_ns_capable(current_user_ns())) 2036 return -EPERM; 2037 2038 error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd); 2039 if (error) 2040 return error; 2041 } 2042 2043 /* 2044 * arg_lock protects concurrent updates but we still need mmap_lock for 2045 * read to exclude races with sys_brk. 2046 */ 2047 mmap_read_lock(mm); 2048 2049 /* 2050 * We don't validate if these members are pointing to 2051 * real present VMAs because application may have correspond 2052 * VMAs already unmapped and kernel uses these members for statistics 2053 * output in procfs mostly, except 2054 * 2055 * - @start_brk/@brk which are used in do_brk_flags but kernel lookups 2056 * for VMAs when updating these members so anything wrong written 2057 * here cause kernel to swear at userspace program but won't lead 2058 * to any problem in kernel itself 2059 */ 2060 2061 spin_lock(&mm->arg_lock); 2062 mm->start_code = prctl_map.start_code; 2063 mm->end_code = prctl_map.end_code; 2064 mm->start_data = prctl_map.start_data; 2065 mm->end_data = prctl_map.end_data; 2066 mm->start_brk = prctl_map.start_brk; 2067 mm->brk = prctl_map.brk; 2068 mm->start_stack = prctl_map.start_stack; 2069 mm->arg_start = prctl_map.arg_start; 2070 mm->arg_end = prctl_map.arg_end; 2071 mm->env_start = prctl_map.env_start; 2072 mm->env_end = prctl_map.env_end; 2073 spin_unlock(&mm->arg_lock); 2074 2075 /* 2076 * Note this update of @saved_auxv is lockless thus 2077 * if someone reads this member in procfs while we're 2078 * updating -- it may get partly updated results. It's 2079 * known and acceptable trade off: we leave it as is to 2080 * not introduce additional locks here making the kernel 2081 * more complex. 2082 */ 2083 if (prctl_map.auxv_size) 2084 memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv)); 2085 2086 mmap_read_unlock(mm); 2087 return 0; 2088 } 2089 #endif /* CONFIG_CHECKPOINT_RESTORE */ 2090 2091 static int prctl_set_auxv(struct mm_struct *mm, unsigned long addr, 2092 unsigned long len) 2093 { 2094 /* 2095 * This doesn't move the auxiliary vector itself since it's pinned to 2096 * mm_struct, but it permits filling the vector with new values. It's 2097 * up to the caller to provide sane values here, otherwise userspace 2098 * tools which use this vector might be unhappy. 2099 */ 2100 unsigned long user_auxv[AT_VECTOR_SIZE] = {}; 2101 2102 if (len > sizeof(user_auxv)) 2103 return -EINVAL; 2104 2105 if (copy_from_user(user_auxv, (const void __user *)addr, len)) 2106 return -EFAULT; 2107 2108 /* Make sure the last entry is always AT_NULL */ 2109 user_auxv[AT_VECTOR_SIZE - 2] = 0; 2110 user_auxv[AT_VECTOR_SIZE - 1] = 0; 2111 2112 BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv)); 2113 2114 task_lock(current); 2115 memcpy(mm->saved_auxv, user_auxv, len); 2116 task_unlock(current); 2117 2118 return 0; 2119 } 2120 2121 static int prctl_set_mm(int opt, unsigned long addr, 2122 unsigned long arg4, unsigned long arg5) 2123 { 2124 struct mm_struct *mm = current->mm; 2125 struct prctl_mm_map prctl_map = { 2126 .auxv = NULL, 2127 .auxv_size = 0, 2128 .exe_fd = -1, 2129 }; 2130 struct vm_area_struct *vma; 2131 int error; 2132 2133 if (arg5 || (arg4 && (opt != PR_SET_MM_AUXV && 2134 opt != PR_SET_MM_MAP && 2135 opt != PR_SET_MM_MAP_SIZE))) 2136 return -EINVAL; 2137 2138 #ifdef CONFIG_CHECKPOINT_RESTORE 2139 if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE) 2140 return prctl_set_mm_map(opt, (const void __user *)addr, arg4); 2141 #endif 2142 2143 if (!capable(CAP_SYS_RESOURCE)) 2144 return -EPERM; 2145 2146 if (opt == PR_SET_MM_EXE_FILE) 2147 return prctl_set_mm_exe_file(mm, (unsigned int)addr); 2148 2149 if (opt == PR_SET_MM_AUXV) 2150 return prctl_set_auxv(mm, addr, arg4); 2151 2152 if (addr >= TASK_SIZE || addr < mmap_min_addr) 2153 return -EINVAL; 2154 2155 error = -EINVAL; 2156 2157 /* 2158 * arg_lock protects concurrent updates of arg boundaries, we need 2159 * mmap_lock for a) concurrent sys_brk, b) finding VMA for addr 2160 * validation. 2161 */ 2162 mmap_read_lock(mm); 2163 vma = find_vma(mm, addr); 2164 2165 spin_lock(&mm->arg_lock); 2166 prctl_map.start_code = mm->start_code; 2167 prctl_map.end_code = mm->end_code; 2168 prctl_map.start_data = mm->start_data; 2169 prctl_map.end_data = mm->end_data; 2170 prctl_map.start_brk = mm->start_brk; 2171 prctl_map.brk = mm->brk; 2172 prctl_map.start_stack = mm->start_stack; 2173 prctl_map.arg_start = mm->arg_start; 2174 prctl_map.arg_end = mm->arg_end; 2175 prctl_map.env_start = mm->env_start; 2176 prctl_map.env_end = mm->env_end; 2177 2178 switch (opt) { 2179 case PR_SET_MM_START_CODE: 2180 prctl_map.start_code = addr; 2181 break; 2182 case PR_SET_MM_END_CODE: 2183 prctl_map.end_code = addr; 2184 break; 2185 case PR_SET_MM_START_DATA: 2186 prctl_map.start_data = addr; 2187 break; 2188 case PR_SET_MM_END_DATA: 2189 prctl_map.end_data = addr; 2190 break; 2191 case PR_SET_MM_START_STACK: 2192 prctl_map.start_stack = addr; 2193 break; 2194 case PR_SET_MM_START_BRK: 2195 prctl_map.start_brk = addr; 2196 break; 2197 case PR_SET_MM_BRK: 2198 prctl_map.brk = addr; 2199 break; 2200 case PR_SET_MM_ARG_START: 2201 prctl_map.arg_start = addr; 2202 break; 2203 case PR_SET_MM_ARG_END: 2204 prctl_map.arg_end = addr; 2205 break; 2206 case PR_SET_MM_ENV_START: 2207 prctl_map.env_start = addr; 2208 break; 2209 case PR_SET_MM_ENV_END: 2210 prctl_map.env_end = addr; 2211 break; 2212 default: 2213 goto out; 2214 } 2215 2216 error = validate_prctl_map_addr(&prctl_map); 2217 if (error) 2218 goto out; 2219 2220 switch (opt) { 2221 /* 2222 * If command line arguments and environment 2223 * are placed somewhere else on stack, we can 2224 * set them up here, ARG_START/END to setup 2225 * command line arguments and ENV_START/END 2226 * for environment. 2227 */ 2228 case PR_SET_MM_START_STACK: 2229 case PR_SET_MM_ARG_START: 2230 case PR_SET_MM_ARG_END: 2231 case PR_SET_MM_ENV_START: 2232 case PR_SET_MM_ENV_END: 2233 if (!vma) { 2234 error = -EFAULT; 2235 goto out; 2236 } 2237 } 2238 2239 mm->start_code = prctl_map.start_code; 2240 mm->end_code = prctl_map.end_code; 2241 mm->start_data = prctl_map.start_data; 2242 mm->end_data = prctl_map.end_data; 2243 mm->start_brk = prctl_map.start_brk; 2244 mm->brk = prctl_map.brk; 2245 mm->start_stack = prctl_map.start_stack; 2246 mm->arg_start = prctl_map.arg_start; 2247 mm->arg_end = prctl_map.arg_end; 2248 mm->env_start = prctl_map.env_start; 2249 mm->env_end = prctl_map.env_end; 2250 2251 error = 0; 2252 out: 2253 spin_unlock(&mm->arg_lock); 2254 mmap_read_unlock(mm); 2255 return error; 2256 } 2257 2258 #ifdef CONFIG_CHECKPOINT_RESTORE 2259 static int prctl_get_tid_address(struct task_struct *me, int __user * __user *tid_addr) 2260 { 2261 return put_user(me->clear_child_tid, tid_addr); 2262 } 2263 #else 2264 static int prctl_get_tid_address(struct task_struct *me, int __user * __user *tid_addr) 2265 { 2266 return -EINVAL; 2267 } 2268 #endif 2269 2270 static int propagate_has_child_subreaper(struct task_struct *p, void *data) 2271 { 2272 /* 2273 * If task has has_child_subreaper - all its descendants 2274 * already have these flag too and new descendants will 2275 * inherit it on fork, skip them. 2276 * 2277 * If we've found child_reaper - skip descendants in 2278 * it's subtree as they will never get out pidns. 2279 */ 2280 if (p->signal->has_child_subreaper || 2281 is_child_reaper(task_pid(p))) 2282 return 0; 2283 2284 p->signal->has_child_subreaper = 1; 2285 return 1; 2286 } 2287 2288 int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which) 2289 { 2290 return -EINVAL; 2291 } 2292 2293 int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which, 2294 unsigned long ctrl) 2295 { 2296 return -EINVAL; 2297 } 2298 2299 #define PR_IO_FLUSHER (PF_MEMALLOC_NOIO | PF_LOCAL_THROTTLE) 2300 2301 #ifdef CONFIG_ANON_VMA_NAME 2302 2303 #define ANON_VMA_NAME_MAX_LEN 80 2304 #define ANON_VMA_NAME_INVALID_CHARS "\\`$[]" 2305 2306 static inline bool is_valid_name_char(char ch) 2307 { 2308 /* printable ascii characters, excluding ANON_VMA_NAME_INVALID_CHARS */ 2309 return ch > 0x1f && ch < 0x7f && 2310 !strchr(ANON_VMA_NAME_INVALID_CHARS, ch); 2311 } 2312 2313 static int prctl_set_vma(unsigned long opt, unsigned long addr, 2314 unsigned long size, unsigned long arg) 2315 { 2316 struct mm_struct *mm = current->mm; 2317 const char __user *uname; 2318 struct anon_vma_name *anon_name = NULL; 2319 int error; 2320 2321 switch (opt) { 2322 case PR_SET_VMA_ANON_NAME: 2323 uname = (const char __user *)arg; 2324 if (uname) { 2325 char *name, *pch; 2326 2327 name = strndup_user(uname, ANON_VMA_NAME_MAX_LEN); 2328 if (IS_ERR(name)) 2329 return PTR_ERR(name); 2330 2331 for (pch = name; *pch != '\0'; pch++) { 2332 if (!is_valid_name_char(*pch)) { 2333 kfree(name); 2334 return -EINVAL; 2335 } 2336 } 2337 /* anon_vma has its own copy */ 2338 anon_name = anon_vma_name_alloc(name); 2339 kfree(name); 2340 if (!anon_name) 2341 return -ENOMEM; 2342 2343 } 2344 2345 mmap_write_lock(mm); 2346 error = madvise_set_anon_name(mm, addr, size, anon_name); 2347 mmap_write_unlock(mm); 2348 anon_vma_name_put(anon_name); 2349 break; 2350 default: 2351 error = -EINVAL; 2352 } 2353 2354 return error; 2355 } 2356 2357 #else /* CONFIG_ANON_VMA_NAME */ 2358 static int prctl_set_vma(unsigned long opt, unsigned long start, 2359 unsigned long size, unsigned long arg) 2360 { 2361 return -EINVAL; 2362 } 2363 #endif /* CONFIG_ANON_VMA_NAME */ 2364 2365 static inline int prctl_set_mdwe(unsigned long bits, unsigned long arg3, 2366 unsigned long arg4, unsigned long arg5) 2367 { 2368 if (arg3 || arg4 || arg5) 2369 return -EINVAL; 2370 2371 if (bits & ~(PR_MDWE_REFUSE_EXEC_GAIN)) 2372 return -EINVAL; 2373 2374 if (bits & PR_MDWE_REFUSE_EXEC_GAIN) 2375 set_bit(MMF_HAS_MDWE, ¤t->mm->flags); 2376 else if (test_bit(MMF_HAS_MDWE, ¤t->mm->flags)) 2377 return -EPERM; /* Cannot unset the flag */ 2378 2379 return 0; 2380 } 2381 2382 static inline int prctl_get_mdwe(unsigned long arg2, unsigned long arg3, 2383 unsigned long arg4, unsigned long arg5) 2384 { 2385 if (arg2 || arg3 || arg4 || arg5) 2386 return -EINVAL; 2387 2388 return test_bit(MMF_HAS_MDWE, ¤t->mm->flags) ? 2389 PR_MDWE_REFUSE_EXEC_GAIN : 0; 2390 } 2391 2392 static int prctl_get_auxv(void __user *addr, unsigned long len) 2393 { 2394 struct mm_struct *mm = current->mm; 2395 unsigned long size = min_t(unsigned long, sizeof(mm->saved_auxv), len); 2396 2397 if (size && copy_to_user(addr, mm->saved_auxv, size)) 2398 return -EFAULT; 2399 return sizeof(mm->saved_auxv); 2400 } 2401 2402 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, 2403 unsigned long, arg4, unsigned long, arg5) 2404 { 2405 struct task_struct *me = current; 2406 unsigned char comm[sizeof(me->comm)]; 2407 long error; 2408 2409 error = security_task_prctl(option, arg2, arg3, arg4, arg5); 2410 if (error != -ENOSYS) 2411 return error; 2412 2413 error = 0; 2414 switch (option) { 2415 case PR_SET_PDEATHSIG: 2416 if (!valid_signal(arg2)) { 2417 error = -EINVAL; 2418 break; 2419 } 2420 me->pdeath_signal = arg2; 2421 break; 2422 case PR_GET_PDEATHSIG: 2423 error = put_user(me->pdeath_signal, (int __user *)arg2); 2424 break; 2425 case PR_GET_DUMPABLE: 2426 error = get_dumpable(me->mm); 2427 break; 2428 case PR_SET_DUMPABLE: 2429 if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) { 2430 error = -EINVAL; 2431 break; 2432 } 2433 set_dumpable(me->mm, arg2); 2434 break; 2435 2436 case PR_SET_UNALIGN: 2437 error = SET_UNALIGN_CTL(me, arg2); 2438 break; 2439 case PR_GET_UNALIGN: 2440 error = GET_UNALIGN_CTL(me, arg2); 2441 break; 2442 case PR_SET_FPEMU: 2443 error = SET_FPEMU_CTL(me, arg2); 2444 break; 2445 case PR_GET_FPEMU: 2446 error = GET_FPEMU_CTL(me, arg2); 2447 break; 2448 case PR_SET_FPEXC: 2449 error = SET_FPEXC_CTL(me, arg2); 2450 break; 2451 case PR_GET_FPEXC: 2452 error = GET_FPEXC_CTL(me, arg2); 2453 break; 2454 case PR_GET_TIMING: 2455 error = PR_TIMING_STATISTICAL; 2456 break; 2457 case PR_SET_TIMING: 2458 if (arg2 != PR_TIMING_STATISTICAL) 2459 error = -EINVAL; 2460 break; 2461 case PR_SET_NAME: 2462 comm[sizeof(me->comm) - 1] = 0; 2463 if (strncpy_from_user(comm, (char __user *)arg2, 2464 sizeof(me->comm) - 1) < 0) 2465 return -EFAULT; 2466 set_task_comm(me, comm); 2467 proc_comm_connector(me); 2468 break; 2469 case PR_GET_NAME: 2470 get_task_comm(comm, me); 2471 if (copy_to_user((char __user *)arg2, comm, sizeof(comm))) 2472 return -EFAULT; 2473 break; 2474 case PR_GET_ENDIAN: 2475 error = GET_ENDIAN(me, arg2); 2476 break; 2477 case PR_SET_ENDIAN: 2478 error = SET_ENDIAN(me, arg2); 2479 break; 2480 case PR_GET_SECCOMP: 2481 error = prctl_get_seccomp(); 2482 break; 2483 case PR_SET_SECCOMP: 2484 error = prctl_set_seccomp(arg2, (char __user *)arg3); 2485 break; 2486 case PR_GET_TSC: 2487 error = GET_TSC_CTL(arg2); 2488 break; 2489 case PR_SET_TSC: 2490 error = SET_TSC_CTL(arg2); 2491 break; 2492 case PR_TASK_PERF_EVENTS_DISABLE: 2493 error = perf_event_task_disable(); 2494 break; 2495 case PR_TASK_PERF_EVENTS_ENABLE: 2496 error = perf_event_task_enable(); 2497 break; 2498 case PR_GET_TIMERSLACK: 2499 if (current->timer_slack_ns > ULONG_MAX) 2500 error = ULONG_MAX; 2501 else 2502 error = current->timer_slack_ns; 2503 break; 2504 case PR_SET_TIMERSLACK: 2505 if (arg2 <= 0) 2506 current->timer_slack_ns = 2507 current->default_timer_slack_ns; 2508 else 2509 current->timer_slack_ns = arg2; 2510 break; 2511 case PR_MCE_KILL: 2512 if (arg4 | arg5) 2513 return -EINVAL; 2514 switch (arg2) { 2515 case PR_MCE_KILL_CLEAR: 2516 if (arg3 != 0) 2517 return -EINVAL; 2518 current->flags &= ~PF_MCE_PROCESS; 2519 break; 2520 case PR_MCE_KILL_SET: 2521 current->flags |= PF_MCE_PROCESS; 2522 if (arg3 == PR_MCE_KILL_EARLY) 2523 current->flags |= PF_MCE_EARLY; 2524 else if (arg3 == PR_MCE_KILL_LATE) 2525 current->flags &= ~PF_MCE_EARLY; 2526 else if (arg3 == PR_MCE_KILL_DEFAULT) 2527 current->flags &= 2528 ~(PF_MCE_EARLY|PF_MCE_PROCESS); 2529 else 2530 return -EINVAL; 2531 break; 2532 case PR_GET_AUXV: 2533 if (arg4 || arg5) 2534 return -EINVAL; 2535 error = prctl_get_auxv((void __user *)arg2, arg3); 2536 break; 2537 default: 2538 return -EINVAL; 2539 } 2540 break; 2541 case PR_MCE_KILL_GET: 2542 if (arg2 | arg3 | arg4 | arg5) 2543 return -EINVAL; 2544 if (current->flags & PF_MCE_PROCESS) 2545 error = (current->flags & PF_MCE_EARLY) ? 2546 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE; 2547 else 2548 error = PR_MCE_KILL_DEFAULT; 2549 break; 2550 case PR_SET_MM: 2551 error = prctl_set_mm(arg2, arg3, arg4, arg5); 2552 break; 2553 case PR_GET_TID_ADDRESS: 2554 error = prctl_get_tid_address(me, (int __user * __user *)arg2); 2555 break; 2556 case PR_SET_CHILD_SUBREAPER: 2557 me->signal->is_child_subreaper = !!arg2; 2558 if (!arg2) 2559 break; 2560 2561 walk_process_tree(me, propagate_has_child_subreaper, NULL); 2562 break; 2563 case PR_GET_CHILD_SUBREAPER: 2564 error = put_user(me->signal->is_child_subreaper, 2565 (int __user *)arg2); 2566 break; 2567 case PR_SET_NO_NEW_PRIVS: 2568 if (arg2 != 1 || arg3 || arg4 || arg5) 2569 return -EINVAL; 2570 2571 task_set_no_new_privs(current); 2572 break; 2573 case PR_GET_NO_NEW_PRIVS: 2574 if (arg2 || arg3 || arg4 || arg5) 2575 return -EINVAL; 2576 return task_no_new_privs(current) ? 1 : 0; 2577 case PR_GET_THP_DISABLE: 2578 if (arg2 || arg3 || arg4 || arg5) 2579 return -EINVAL; 2580 error = !!test_bit(MMF_DISABLE_THP, &me->mm->flags); 2581 break; 2582 case PR_SET_THP_DISABLE: 2583 if (arg3 || arg4 || arg5) 2584 return -EINVAL; 2585 if (mmap_write_lock_killable(me->mm)) 2586 return -EINTR; 2587 if (arg2) 2588 set_bit(MMF_DISABLE_THP, &me->mm->flags); 2589 else 2590 clear_bit(MMF_DISABLE_THP, &me->mm->flags); 2591 mmap_write_unlock(me->mm); 2592 break; 2593 case PR_MPX_ENABLE_MANAGEMENT: 2594 case PR_MPX_DISABLE_MANAGEMENT: 2595 /* No longer implemented: */ 2596 return -EINVAL; 2597 case PR_SET_FP_MODE: 2598 error = SET_FP_MODE(me, arg2); 2599 break; 2600 case PR_GET_FP_MODE: 2601 error = GET_FP_MODE(me); 2602 break; 2603 case PR_SVE_SET_VL: 2604 error = SVE_SET_VL(arg2); 2605 break; 2606 case PR_SVE_GET_VL: 2607 error = SVE_GET_VL(); 2608 break; 2609 case PR_SME_SET_VL: 2610 error = SME_SET_VL(arg2); 2611 break; 2612 case PR_SME_GET_VL: 2613 error = SME_GET_VL(); 2614 break; 2615 case PR_GET_SPECULATION_CTRL: 2616 if (arg3 || arg4 || arg5) 2617 return -EINVAL; 2618 error = arch_prctl_spec_ctrl_get(me, arg2); 2619 break; 2620 case PR_SET_SPECULATION_CTRL: 2621 if (arg4 || arg5) 2622 return -EINVAL; 2623 error = arch_prctl_spec_ctrl_set(me, arg2, arg3); 2624 break; 2625 case PR_PAC_RESET_KEYS: 2626 if (arg3 || arg4 || arg5) 2627 return -EINVAL; 2628 error = PAC_RESET_KEYS(me, arg2); 2629 break; 2630 case PR_PAC_SET_ENABLED_KEYS: 2631 if (arg4 || arg5) 2632 return -EINVAL; 2633 error = PAC_SET_ENABLED_KEYS(me, arg2, arg3); 2634 break; 2635 case PR_PAC_GET_ENABLED_KEYS: 2636 if (arg2 || arg3 || arg4 || arg5) 2637 return -EINVAL; 2638 error = PAC_GET_ENABLED_KEYS(me); 2639 break; 2640 case PR_SET_TAGGED_ADDR_CTRL: 2641 if (arg3 || arg4 || arg5) 2642 return -EINVAL; 2643 error = SET_TAGGED_ADDR_CTRL(arg2); 2644 break; 2645 case PR_GET_TAGGED_ADDR_CTRL: 2646 if (arg2 || arg3 || arg4 || arg5) 2647 return -EINVAL; 2648 error = GET_TAGGED_ADDR_CTRL(); 2649 break; 2650 case PR_SET_IO_FLUSHER: 2651 if (!capable(CAP_SYS_RESOURCE)) 2652 return -EPERM; 2653 2654 if (arg3 || arg4 || arg5) 2655 return -EINVAL; 2656 2657 if (arg2 == 1) 2658 current->flags |= PR_IO_FLUSHER; 2659 else if (!arg2) 2660 current->flags &= ~PR_IO_FLUSHER; 2661 else 2662 return -EINVAL; 2663 break; 2664 case PR_GET_IO_FLUSHER: 2665 if (!capable(CAP_SYS_RESOURCE)) 2666 return -EPERM; 2667 2668 if (arg2 || arg3 || arg4 || arg5) 2669 return -EINVAL; 2670 2671 error = (current->flags & PR_IO_FLUSHER) == PR_IO_FLUSHER; 2672 break; 2673 case PR_SET_SYSCALL_USER_DISPATCH: 2674 error = set_syscall_user_dispatch(arg2, arg3, arg4, 2675 (char __user *) arg5); 2676 break; 2677 #ifdef CONFIG_SCHED_CORE 2678 case PR_SCHED_CORE: 2679 error = sched_core_share_pid(arg2, arg3, arg4, arg5); 2680 break; 2681 #endif 2682 case PR_SET_MDWE: 2683 error = prctl_set_mdwe(arg2, arg3, arg4, arg5); 2684 break; 2685 case PR_GET_MDWE: 2686 error = prctl_get_mdwe(arg2, arg3, arg4, arg5); 2687 break; 2688 case PR_SET_VMA: 2689 error = prctl_set_vma(arg2, arg3, arg4, arg5); 2690 break; 2691 #ifdef CONFIG_KSM 2692 case PR_SET_MEMORY_MERGE: 2693 if (arg3 || arg4 || arg5) 2694 return -EINVAL; 2695 if (mmap_write_lock_killable(me->mm)) 2696 return -EINTR; 2697 2698 if (arg2) 2699 error = ksm_enable_merge_any(me->mm); 2700 else 2701 error = ksm_disable_merge_any(me->mm); 2702 mmap_write_unlock(me->mm); 2703 break; 2704 case PR_GET_MEMORY_MERGE: 2705 if (arg2 || arg3 || arg4 || arg5) 2706 return -EINVAL; 2707 2708 error = !!test_bit(MMF_VM_MERGE_ANY, &me->mm->flags); 2709 break; 2710 #endif 2711 default: 2712 error = -EINVAL; 2713 break; 2714 } 2715 return error; 2716 } 2717 2718 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep, 2719 struct getcpu_cache __user *, unused) 2720 { 2721 int err = 0; 2722 int cpu = raw_smp_processor_id(); 2723 2724 if (cpup) 2725 err |= put_user(cpu, cpup); 2726 if (nodep) 2727 err |= put_user(cpu_to_node(cpu), nodep); 2728 return err ? -EFAULT : 0; 2729 } 2730 2731 /** 2732 * do_sysinfo - fill in sysinfo struct 2733 * @info: pointer to buffer to fill 2734 */ 2735 static int do_sysinfo(struct sysinfo *info) 2736 { 2737 unsigned long mem_total, sav_total; 2738 unsigned int mem_unit, bitcount; 2739 struct timespec64 tp; 2740 2741 memset(info, 0, sizeof(struct sysinfo)); 2742 2743 ktime_get_boottime_ts64(&tp); 2744 timens_add_boottime(&tp); 2745 info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0); 2746 2747 get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT); 2748 2749 info->procs = nr_threads; 2750 2751 si_meminfo(info); 2752 si_swapinfo(info); 2753 2754 /* 2755 * If the sum of all the available memory (i.e. ram + swap) 2756 * is less than can be stored in a 32 bit unsigned long then 2757 * we can be binary compatible with 2.2.x kernels. If not, 2758 * well, in that case 2.2.x was broken anyways... 2759 * 2760 * -Erik Andersen <andersee@debian.org> 2761 */ 2762 2763 mem_total = info->totalram + info->totalswap; 2764 if (mem_total < info->totalram || mem_total < info->totalswap) 2765 goto out; 2766 bitcount = 0; 2767 mem_unit = info->mem_unit; 2768 while (mem_unit > 1) { 2769 bitcount++; 2770 mem_unit >>= 1; 2771 sav_total = mem_total; 2772 mem_total <<= 1; 2773 if (mem_total < sav_total) 2774 goto out; 2775 } 2776 2777 /* 2778 * If mem_total did not overflow, multiply all memory values by 2779 * info->mem_unit and set it to 1. This leaves things compatible 2780 * with 2.2.x, and also retains compatibility with earlier 2.4.x 2781 * kernels... 2782 */ 2783 2784 info->mem_unit = 1; 2785 info->totalram <<= bitcount; 2786 info->freeram <<= bitcount; 2787 info->sharedram <<= bitcount; 2788 info->bufferram <<= bitcount; 2789 info->totalswap <<= bitcount; 2790 info->freeswap <<= bitcount; 2791 info->totalhigh <<= bitcount; 2792 info->freehigh <<= bitcount; 2793 2794 out: 2795 return 0; 2796 } 2797 2798 SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info) 2799 { 2800 struct sysinfo val; 2801 2802 do_sysinfo(&val); 2803 2804 if (copy_to_user(info, &val, sizeof(struct sysinfo))) 2805 return -EFAULT; 2806 2807 return 0; 2808 } 2809 2810 #ifdef CONFIG_COMPAT 2811 struct compat_sysinfo { 2812 s32 uptime; 2813 u32 loads[3]; 2814 u32 totalram; 2815 u32 freeram; 2816 u32 sharedram; 2817 u32 bufferram; 2818 u32 totalswap; 2819 u32 freeswap; 2820 u16 procs; 2821 u16 pad; 2822 u32 totalhigh; 2823 u32 freehigh; 2824 u32 mem_unit; 2825 char _f[20-2*sizeof(u32)-sizeof(int)]; 2826 }; 2827 2828 COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info) 2829 { 2830 struct sysinfo s; 2831 struct compat_sysinfo s_32; 2832 2833 do_sysinfo(&s); 2834 2835 /* Check to see if any memory value is too large for 32-bit and scale 2836 * down if needed 2837 */ 2838 if (upper_32_bits(s.totalram) || upper_32_bits(s.totalswap)) { 2839 int bitcount = 0; 2840 2841 while (s.mem_unit < PAGE_SIZE) { 2842 s.mem_unit <<= 1; 2843 bitcount++; 2844 } 2845 2846 s.totalram >>= bitcount; 2847 s.freeram >>= bitcount; 2848 s.sharedram >>= bitcount; 2849 s.bufferram >>= bitcount; 2850 s.totalswap >>= bitcount; 2851 s.freeswap >>= bitcount; 2852 s.totalhigh >>= bitcount; 2853 s.freehigh >>= bitcount; 2854 } 2855 2856 memset(&s_32, 0, sizeof(s_32)); 2857 s_32.uptime = s.uptime; 2858 s_32.loads[0] = s.loads[0]; 2859 s_32.loads[1] = s.loads[1]; 2860 s_32.loads[2] = s.loads[2]; 2861 s_32.totalram = s.totalram; 2862 s_32.freeram = s.freeram; 2863 s_32.sharedram = s.sharedram; 2864 s_32.bufferram = s.bufferram; 2865 s_32.totalswap = s.totalswap; 2866 s_32.freeswap = s.freeswap; 2867 s_32.procs = s.procs; 2868 s_32.totalhigh = s.totalhigh; 2869 s_32.freehigh = s.freehigh; 2870 s_32.mem_unit = s.mem_unit; 2871 if (copy_to_user(info, &s_32, sizeof(s_32))) 2872 return -EFAULT; 2873 return 0; 2874 } 2875 #endif /* CONFIG_COMPAT */ 2876