kernel/sys.c

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This source file includes following definitions.
set_one_prio_perm
set_one_prio
SYSCALL_DEFINE3
SYSCALL_DEFINE2
__sys_setregid
SYSCALL_DEFINE2
__sys_setgid
SYSCALL_DEFINE1
set_user
__sys_setreuid
SYSCALL_DEFINE2
__sys_setuid
SYSCALL_DEFINE1
__sys_setresuid
SYSCALL_DEFINE3
SYSCALL_DEFINE3
__sys_setresgid
SYSCALL_DEFINE3
SYSCALL_DEFINE3
__sys_setfsuid
SYSCALL_DEFINE1
__sys_setfsgid
SYSCALL_DEFINE1
SYSCALL_DEFINE0
SYSCALL_DEFINE0
SYSCALL_DEFINE0
SYSCALL_DEFINE0
SYSCALL_DEFINE0
SYSCALL_DEFINE0
SYSCALL_DEFINE0
do_sys_times
SYSCALL_DEFINE1
clock_t_to_compat_clock_t
COMPAT_SYSCALL_DEFINE1
SYSCALL_DEFINE2
do_getpgid
SYSCALL_DEFINE1
SYSCALL_DEFINE0
SYSCALL_DEFINE1
set_special_pids
ksys_setsid
SYSCALL_DEFINE0
override_release
SYSCALL_DEFINE1
SYSCALL_DEFINE1
SYSCALL_DEFINE1
SYSCALL_DEFINE2
SYSCALL_DEFINE2
SYSCALL_DEFINE2
SYSCALL_DEFINE2
COMPAT_SYSCALL_DEFINE2
COMPAT_SYSCALL_DEFINE2
SYSCALL_DEFINE2
COMPAT_SYSCALL_DEFINE2
rlim64_is_infinity
rlim_to_rlim64
rlim64_to_rlim
do_prlimit
check_prlimit_permission
SYSCALL_DEFINE4
SYSCALL_DEFINE2
accumulate_thread_rusage
getrusage
SYSCALL_DEFINE2
COMPAT_SYSCALL_DEFINE2
SYSCALL_DEFINE1
prctl_set_mm_exe_file
validate_prctl_map_addr
prctl_set_mm_map
prctl_set_auxv
prctl_set_mm
prctl_get_tid_address
prctl_get_tid_address
propagate_has_child_subreaper
arch_prctl_spec_ctrl_get
arch_prctl_spec_ctrl_set
SYSCALL_DEFINE5
SYSCALL_DEFINE3
do_sysinfo
SYSCALL_DEFINE1
COMPAT_SYSCALL_DEFINE1
   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/utsname.h>
  11 #include <linux/mman.h>
  12 #include <linux/reboot.h>
  13 #include <linux/prctl.h>
  14 #include <linux/highuid.h>
  15 #include <linux/fs.h>
  16 #include <linux/kmod.h>
  17 #include <linux/perf_event.h>
  18 #include <linux/resource.h>
  19 #include <linux/kernel.h>
  20 #include <linux/workqueue.h>
  21 #include <linux/capability.h>
  22 #include <linux/device.h>
  23 #include <linux/key.h>
  24 #include <linux/times.h>
  25 #include <linux/posix-timers.h>
  26 #include <linux/security.h>
  27 #include <linux/dcookies.h>
  28 #include <linux/suspend.h>
  29 #include <linux/tty.h>
  30 #include <linux/signal.h>
  31 #include <linux/cn_proc.h>
  32 #include <linux/getcpu.h>
  33 #include <linux/task_io_accounting_ops.h>
  34 #include <linux/seccomp.h>
  35 #include <linux/cpu.h>
  36 #include <linux/personality.h>
  37 #include <linux/ptrace.h>
  38 #include <linux/fs_struct.h>
  39 #include <linux/file.h>
  40 #include <linux/mount.h>
  41 #include <linux/gfp.h>
  42 #include <linux/syscore_ops.h>
  43 #include <linux/version.h>
  44 #include <linux/ctype.h>
  45 
  46 #include <linux/compat.h>
  47 #include <linux/syscalls.h>
  48 #include <linux/kprobes.h>
  49 #include <linux/user_namespace.h>
  50 #include <linux/binfmts.h>
  51 
  52 #include <linux/sched.h>
  53 #include <linux/sched/autogroup.h>
  54 #include <linux/sched/loadavg.h>
  55 #include <linux/sched/stat.h>
  56 #include <linux/sched/mm.h>
  57 #include <linux/sched/coredump.h>
  58 #include <linux/sched/task.h>
  59 #include <linux/sched/cputime.h>
  60 #include <linux/rcupdate.h>
  61 #include <linux/uidgid.h>
  62 #include <linux/cred.h>
  63 
  64 #include <linux/nospec.h>
  65 
  66 #include <linux/kmsg_dump.h>
  67 /* Move somewhere else to avoid recompiling? */
  68 #include <generated/utsrelease.h>
  69 
  70 #include <linux/uaccess.h>
  71 #include <asm/io.h>
  72 #include <asm/unistd.h>
  73 
  74 #include "uid16.h"
  75 
  76 #ifndef SET_UNALIGN_CTL
  77 # define SET_UNALIGN_CTL(a, b)  (-EINVAL)
  78 #endif
  79 #ifndef GET_UNALIGN_CTL
  80 # define GET_UNALIGN_CTL(a, b)  (-EINVAL)
  81 #endif
  82 #ifndef SET_FPEMU_CTL
  83 # define SET_FPEMU_CTL(a, b)    (-EINVAL)
  84 #endif
  85 #ifndef GET_FPEMU_CTL
  86 # define GET_FPEMU_CTL(a, b)    (-EINVAL)
  87 #endif
  88 #ifndef SET_FPEXC_CTL
  89 # define SET_FPEXC_CTL(a, b)    (-EINVAL)
  90 #endif
  91 #ifndef GET_FPEXC_CTL
  92 # define GET_FPEXC_CTL(a, b)    (-EINVAL)
  93 #endif
  94 #ifndef GET_ENDIAN
  95 # define GET_ENDIAN(a, b)       (-EINVAL)
  96 #endif
  97 #ifndef SET_ENDIAN
  98 # define SET_ENDIAN(a, b)       (-EINVAL)
  99 #endif
 100 #ifndef GET_TSC_CTL
 101 # define GET_TSC_CTL(a)         (-EINVAL)
 102 #endif
 103 #ifndef SET_TSC_CTL
 104 # define SET_TSC_CTL(a)         (-EINVAL)
 105 #endif
 106 #ifndef GET_FP_MODE
 107 # define GET_FP_MODE(a)         (-EINVAL)
 108 #endif
 109 #ifndef SET_FP_MODE
 110 # define SET_FP_MODE(a,b)       (-EINVAL)
 111 #endif
 112 #ifndef SVE_SET_VL
 113 # define SVE_SET_VL(a)          (-EINVAL)
 114 #endif
 115 #ifndef SVE_GET_VL
 116 # define SVE_GET_VL()           (-EINVAL)
 117 #endif
 118 #ifndef PAC_RESET_KEYS
 119 # define PAC_RESET_KEYS(a, b)   (-EINVAL)
 120 #endif
 121 #ifndef SET_TAGGED_ADDR_CTRL
 122 # define SET_TAGGED_ADDR_CTRL(a)        (-EINVAL)
 123 #endif
 124 #ifndef GET_TAGGED_ADDR_CTRL
 125 # define GET_TAGGED_ADDR_CTRL()         (-EINVAL)
 126 #endif
 127 
 128 /*
 129  * this is where the system-wide overflow UID and GID are defined, for
 130  * architectures that now have 32-bit UID/GID but didn't in the past
 131  */
 132 
 133 int overflowuid = DEFAULT_OVERFLOWUID;
 134 int overflowgid = DEFAULT_OVERFLOWGID;
 135 
 136 EXPORT_SYMBOL(overflowuid);
 137 EXPORT_SYMBOL(overflowgid);
 138 
 139 /*
 140  * the same as above, but for filesystems which can only store a 16-bit
 141  * UID and GID. as such, this is needed on all architectures
 142  */
 143 
 144 int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
 145 int fs_overflowgid = DEFAULT_FS_OVERFLOWGID;
 146 
 147 EXPORT_SYMBOL(fs_overflowuid);
 148 EXPORT_SYMBOL(fs_overflowgid);
 149 
 150 /*
 151  * Returns true if current's euid is same as p's uid or euid,
 152  * or has CAP_SYS_NICE to p's user_ns.
 153  *
 154  * Called with rcu_read_lock, creds are safe
 155  */
 156 static bool set_one_prio_perm(struct task_struct *p)
 157 {
 158         const struct cred *cred = current_cred(), *pcred = __task_cred(p);
 159 
 160         if (uid_eq(pcred->uid,  cred->euid) ||
 161             uid_eq(pcred->euid, cred->euid))
 162                 return true;
 163         if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
 164                 return true;
 165         return false;
 166 }
 167 
 168 /*
 169  * set the priority of a task
 170  * - the caller must hold the RCU read lock
 171  */
 172 static int set_one_prio(struct task_struct *p, int niceval, int error)
 173 {
 174         int no_nice;
 175 
 176         if (!set_one_prio_perm(p)) {
 177                 error = -EPERM;
 178                 goto out;
 179         }
 180         if (niceval < task_nice(p) && !can_nice(p, niceval)) {
 181                 error = -EACCES;
 182                 goto out;
 183         }
 184         no_nice = security_task_setnice(p, niceval);
 185         if (no_nice) {
 186                 error = no_nice;
 187                 goto out;
 188         }
 189         if (error == -ESRCH)
 190                 error = 0;
 191         set_user_nice(p, niceval);
 192 out:
 193         return error;
 194 }
 195 
 196 SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
 197 {
 198         struct task_struct *g, *p;
 199         struct user_struct *user;
 200         const struct cred *cred = current_cred();
 201         int error = -EINVAL;
 202         struct pid *pgrp;
 203         kuid_t uid;
 204 
 205         if (which > PRIO_USER || which < PRIO_PROCESS)
 206                 goto out;
 207 
 208         /* normalize: avoid signed division (rounding problems) */
 209         error = -ESRCH;
 210         if (niceval < MIN_NICE)
 211                 niceval = MIN_NICE;
 212         if (niceval > MAX_NICE)
 213                 niceval = MAX_NICE;
 214 
 215         rcu_read_lock();
 216         read_lock(&tasklist_lock);
 217         switch (which) {
 218         case PRIO_PROCESS:
 219                 if (who)
 220                         p = find_task_by_vpid(who);
 221                 else
 222                         p = current;
 223                 if (p)
 224                         error = set_one_prio(p, niceval, error);
 225                 break;
 226         case PRIO_PGRP:
 227                 if (who)
 228                         pgrp = find_vpid(who);
 229                 else
 230                         pgrp = task_pgrp(current);
 231                 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 232                         error = set_one_prio(p, niceval, error);
 233                 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 234                 break;
 235         case PRIO_USER:
 236                 uid = make_kuid(cred->user_ns, who);
 237                 user = cred->user;
 238                 if (!who)
 239                         uid = cred->uid;
 240                 else if (!uid_eq(uid, cred->uid)) {
 241                         user = find_user(uid);
 242                         if (!user)
 243                                 goto out_unlock;        /* No processes for this user */
 244                 }
 245                 do_each_thread(g, p) {
 246                         if (uid_eq(task_uid(p), uid) && task_pid_vnr(p))
 247                                 error = set_one_prio(p, niceval, error);
 248                 } while_each_thread(g, p);
 249                 if (!uid_eq(uid, cred->uid))
 250                         free_uid(user);         /* For find_user() */
 251                 break;
 252         }
 253 out_unlock:
 254         read_unlock(&tasklist_lock);
 255         rcu_read_unlock();
 256 out:
 257         return error;
 258 }
 259 
 260 /*
 261  * Ugh. To avoid negative return values, "getpriority()" will
 262  * not return the normal nice-value, but a negated value that
 263  * has been offset by 20 (ie it returns 40..1 instead of -20..19)
 264  * to stay compatible.
 265  */
 266 SYSCALL_DEFINE2(getpriority, int, which, int, who)
 267 {
 268         struct task_struct *g, *p;
 269         struct user_struct *user;
 270         const struct cred *cred = current_cred();
 271         long niceval, retval = -ESRCH;
 272         struct pid *pgrp;
 273         kuid_t uid;
 274 
 275         if (which > PRIO_USER || which < PRIO_PROCESS)
 276                 return -EINVAL;
 277 
 278         rcu_read_lock();
 279         read_lock(&tasklist_lock);
 280         switch (which) {
 281         case PRIO_PROCESS:
 282                 if (who)
 283                         p = find_task_by_vpid(who);
 284                 else
 285                         p = current;
 286                 if (p) {
 287                         niceval = nice_to_rlimit(task_nice(p));
 288                         if (niceval > retval)
 289                                 retval = niceval;
 290                 }
 291                 break;
 292         case PRIO_PGRP:
 293                 if (who)
 294                         pgrp = find_vpid(who);
 295                 else
 296                         pgrp = task_pgrp(current);
 297                 do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
 298                         niceval = nice_to_rlimit(task_nice(p));
 299                         if (niceval > retval)
 300                                 retval = niceval;
 301                 } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
 302                 break;
 303         case PRIO_USER:
 304                 uid = make_kuid(cred->user_ns, who);
 305                 user = cred->user;
 306                 if (!who)
 307                         uid = cred->uid;
 308                 else if (!uid_eq(uid, cred->uid)) {
 309                         user = find_user(uid);
 310                         if (!user)
 311                                 goto out_unlock;        /* No processes for this user */
 312                 }
 313                 do_each_thread(g, p) {
 314                         if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) {
 315                                 niceval = nice_to_rlimit(task_nice(p));
 316                                 if (niceval > retval)
 317                                         retval = niceval;
 318                         }
 319                 } while_each_thread(g, p);
 320                 if (!uid_eq(uid, cred->uid))
 321                         free_uid(user);         /* for find_user() */
 322                 break;
 323         }
 324 out_unlock:
 325         read_unlock(&tasklist_lock);
 326         rcu_read_unlock();
 327 
 328         return retval;
 329 }
 330 
 331 /*
 332  * Unprivileged users may change the real gid to the effective gid
 333  * or vice versa.  (BSD-style)
 334  *
 335  * If you set the real gid at all, or set the effective gid to a value not
 336  * equal to the real gid, then the saved gid is set to the new effective gid.
 337  *
 338  * This makes it possible for a setgid program to completely drop its
 339  * privileges, which is often a useful assertion to make when you are doing
 340  * a security audit over a program.
 341  *
 342  * The general idea is that a program which uses just setregid() will be
 343  * 100% compatible with BSD.  A program which uses just setgid() will be
 344  * 100% compatible with POSIX with saved IDs.
 345  *
 346  * SMP: There are not races, the GIDs are checked only by filesystem
 347  *      operations (as far as semantic preservation is concerned).
 348  */
 349 #ifdef CONFIG_MULTIUSER
 350 long __sys_setregid(gid_t rgid, gid_t egid)
 351 {
 352         struct user_namespace *ns = current_user_ns();
 353         const struct cred *old;
 354         struct cred *new;
 355         int retval;
 356         kgid_t krgid, kegid;
 357 
 358         krgid = make_kgid(ns, rgid);
 359         kegid = make_kgid(ns, egid);
 360 
 361         if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 362                 return -EINVAL;
 363         if ((egid != (gid_t) -1) && !gid_valid(kegid))
 364                 return -EINVAL;
 365 
 366         new = prepare_creds();
 367         if (!new)
 368                 return -ENOMEM;
 369         old = current_cred();
 370 
 371         retval = -EPERM;
 372         if (rgid != (gid_t) -1) {
 373                 if (gid_eq(old->gid, krgid) ||
 374                     gid_eq(old->egid, krgid) ||
 375                     ns_capable(old->user_ns, CAP_SETGID))
 376                         new->gid = krgid;
 377                 else
 378                         goto error;
 379         }
 380         if (egid != (gid_t) -1) {
 381                 if (gid_eq(old->gid, kegid) ||
 382                     gid_eq(old->egid, kegid) ||
 383                     gid_eq(old->sgid, kegid) ||
 384                     ns_capable(old->user_ns, CAP_SETGID))
 385                         new->egid = kegid;
 386                 else
 387                         goto error;
 388         }
 389 
 390         if (rgid != (gid_t) -1 ||
 391             (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
 392                 new->sgid = new->egid;
 393         new->fsgid = new->egid;
 394 
 395         return commit_creds(new);
 396 
 397 error:
 398         abort_creds(new);
 399         return retval;
 400 }
 401 
 402 SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
 403 {
 404         return __sys_setregid(rgid, egid);
 405 }
 406 
 407 /*
 408  * setgid() is implemented like SysV w/ SAVED_IDS
 409  *
 410  * SMP: Same implicit races as above.
 411  */
 412 long __sys_setgid(gid_t gid)
 413 {
 414         struct user_namespace *ns = current_user_ns();
 415         const struct cred *old;
 416         struct cred *new;
 417         int retval;
 418         kgid_t kgid;
 419 
 420         kgid = make_kgid(ns, gid);
 421         if (!gid_valid(kgid))
 422                 return -EINVAL;
 423 
 424         new = prepare_creds();
 425         if (!new)
 426                 return -ENOMEM;
 427         old = current_cred();
 428 
 429         retval = -EPERM;
 430         if (ns_capable(old->user_ns, CAP_SETGID))
 431                 new->gid = new->egid = new->sgid = new->fsgid = kgid;
 432         else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
 433                 new->egid = new->fsgid = kgid;
 434         else
 435                 goto error;
 436 
 437         return commit_creds(new);
 438 
 439 error:
 440         abort_creds(new);
 441         return retval;
 442 }
 443 
 444 SYSCALL_DEFINE1(setgid, gid_t, gid)
 445 {
 446         return __sys_setgid(gid);
 447 }
 448 
 449 /*
 450  * change the user struct in a credentials set to match the new UID
 451  */
 452 static int set_user(struct cred *new)
 453 {
 454         struct user_struct *new_user;
 455 
 456         new_user = alloc_uid(new->uid);
 457         if (!new_user)
 458                 return -EAGAIN;
 459 
 460         /*
 461          * We don't fail in case of NPROC limit excess here because too many
 462          * poorly written programs don't check set*uid() return code, assuming
 463          * it never fails if called by root.  We may still enforce NPROC limit
 464          * for programs doing set*uid()+execve() by harmlessly deferring the
 465          * failure to the execve() stage.
 466          */
 467         if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) &&
 468                         new_user != INIT_USER)
 469                 current->flags |= PF_NPROC_EXCEEDED;
 470         else
 471                 current->flags &= ~PF_NPROC_EXCEEDED;
 472 
 473         free_uid(new->user);
 474         new->user = new_user;
 475         return 0;
 476 }
 477 
 478 /*
 479  * Unprivileged users may change the real uid to the effective uid
 480  * or vice versa.  (BSD-style)
 481  *
 482  * If you set the real uid at all, or set the effective uid to a value not
 483  * equal to the real uid, then the saved uid is set to the new effective uid.
 484  *
 485  * This makes it possible for a setuid program to completely drop its
 486  * privileges, which is often a useful assertion to make when you are doing
 487  * a security audit over a program.
 488  *
 489  * The general idea is that a program which uses just setreuid() will be
 490  * 100% compatible with BSD.  A program which uses just setuid() will be
 491  * 100% compatible with POSIX with saved IDs.
 492  */
 493 long __sys_setreuid(uid_t ruid, uid_t euid)
 494 {
 495         struct user_namespace *ns = current_user_ns();
 496         const struct cred *old;
 497         struct cred *new;
 498         int retval;
 499         kuid_t kruid, keuid;
 500 
 501         kruid = make_kuid(ns, ruid);
 502         keuid = make_kuid(ns, euid);
 503 
 504         if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 505                 return -EINVAL;
 506         if ((euid != (uid_t) -1) && !uid_valid(keuid))
 507                 return -EINVAL;
 508 
 509         new = prepare_creds();
 510         if (!new)
 511                 return -ENOMEM;
 512         old = current_cred();
 513 
 514         retval = -EPERM;
 515         if (ruid != (uid_t) -1) {
 516                 new->uid = kruid;
 517                 if (!uid_eq(old->uid, kruid) &&
 518                     !uid_eq(old->euid, kruid) &&
 519                     !ns_capable_setid(old->user_ns, CAP_SETUID))
 520                         goto error;
 521         }
 522 
 523         if (euid != (uid_t) -1) {
 524                 new->euid = keuid;
 525                 if (!uid_eq(old->uid, keuid) &&
 526                     !uid_eq(old->euid, keuid) &&
 527                     !uid_eq(old->suid, keuid) &&
 528                     !ns_capable_setid(old->user_ns, CAP_SETUID))
 529                         goto error;
 530         }
 531 
 532         if (!uid_eq(new->uid, old->uid)) {
 533                 retval = set_user(new);
 534                 if (retval < 0)
 535                         goto error;
 536         }
 537         if (ruid != (uid_t) -1 ||
 538             (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
 539                 new->suid = new->euid;
 540         new->fsuid = new->euid;
 541 
 542         retval = security_task_fix_setuid(new, old, LSM_SETID_RE);
 543         if (retval < 0)
 544                 goto error;
 545 
 546         return commit_creds(new);
 547 
 548 error:
 549         abort_creds(new);
 550         return retval;
 551 }
 552 
 553 SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
 554 {
 555         return __sys_setreuid(ruid, euid);
 556 }
 557 
 558 /*
 559  * setuid() is implemented like SysV with SAVED_IDS
 560  *
 561  * Note that SAVED_ID's is deficient in that a setuid root program
 562  * like sendmail, for example, cannot set its uid to be a normal
 563  * user and then switch back, because if you're root, setuid() sets
 564  * the saved uid too.  If you don't like this, blame the bright people
 565  * in the POSIX committee and/or USG.  Note that the BSD-style setreuid()
 566  * will allow a root program to temporarily drop privileges and be able to
 567  * regain them by swapping the real and effective uid.
 568  */
 569 long __sys_setuid(uid_t uid)
 570 {
 571         struct user_namespace *ns = current_user_ns();
 572         const struct cred *old;
 573         struct cred *new;
 574         int retval;
 575         kuid_t kuid;
 576 
 577         kuid = make_kuid(ns, uid);
 578         if (!uid_valid(kuid))
 579                 return -EINVAL;
 580 
 581         new = prepare_creds();
 582         if (!new)
 583                 return -ENOMEM;
 584         old = current_cred();
 585 
 586         retval = -EPERM;
 587         if (ns_capable_setid(old->user_ns, CAP_SETUID)) {
 588                 new->suid = new->uid = kuid;
 589                 if (!uid_eq(kuid, old->uid)) {
 590                         retval = set_user(new);
 591                         if (retval < 0)
 592                                 goto error;
 593                 }
 594         } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
 595                 goto error;
 596         }
 597 
 598         new->fsuid = new->euid = kuid;
 599 
 600         retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
 601         if (retval < 0)
 602                 goto error;
 603 
 604         return commit_creds(new);
 605 
 606 error:
 607         abort_creds(new);
 608         return retval;
 609 }
 610 
 611 SYSCALL_DEFINE1(setuid, uid_t, uid)
 612 {
 613         return __sys_setuid(uid);
 614 }
 615 
 616 
 617 /*
 618  * This function implements a generic ability to update ruid, euid,
 619  * and suid.  This allows you to implement the 4.4 compatible seteuid().
 620  */
 621 long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
 622 {
 623         struct user_namespace *ns = current_user_ns();
 624         const struct cred *old;
 625         struct cred *new;
 626         int retval;
 627         kuid_t kruid, keuid, ksuid;
 628 
 629         kruid = make_kuid(ns, ruid);
 630         keuid = make_kuid(ns, euid);
 631         ksuid = make_kuid(ns, suid);
 632 
 633         if ((ruid != (uid_t) -1) && !uid_valid(kruid))
 634                 return -EINVAL;
 635 
 636         if ((euid != (uid_t) -1) && !uid_valid(keuid))
 637                 return -EINVAL;
 638 
 639         if ((suid != (uid_t) -1) && !uid_valid(ksuid))
 640                 return -EINVAL;
 641 
 642         new = prepare_creds();
 643         if (!new)
 644                 return -ENOMEM;
 645 
 646         old = current_cred();
 647 
 648         retval = -EPERM;
 649         if (!ns_capable_setid(old->user_ns, CAP_SETUID)) {
 650                 if (ruid != (uid_t) -1        && !uid_eq(kruid, old->uid) &&
 651                     !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
 652                         goto error;
 653                 if (euid != (uid_t) -1        && !uid_eq(keuid, old->uid) &&
 654                     !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
 655                         goto error;
 656                 if (suid != (uid_t) -1        && !uid_eq(ksuid, old->uid) &&
 657                     !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
 658                         goto error;
 659         }
 660 
 661         if (ruid != (uid_t) -1) {
 662                 new->uid = kruid;
 663                 if (!uid_eq(kruid, old->uid)) {
 664                         retval = set_user(new);
 665                         if (retval < 0)
 666                                 goto error;
 667                 }
 668         }
 669         if (euid != (uid_t) -1)
 670                 new->euid = keuid;
 671         if (suid != (uid_t) -1)
 672                 new->suid = ksuid;
 673         new->fsuid = new->euid;
 674 
 675         retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
 676         if (retval < 0)
 677                 goto error;
 678 
 679         return commit_creds(new);
 680 
 681 error:
 682         abort_creds(new);
 683         return retval;
 684 }
 685 
 686 SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
 687 {
 688         return __sys_setresuid(ruid, euid, suid);
 689 }
 690 
 691 SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
 692 {
 693         const struct cred *cred = current_cred();
 694         int retval;
 695         uid_t ruid, euid, suid;
 696 
 697         ruid = from_kuid_munged(cred->user_ns, cred->uid);
 698         euid = from_kuid_munged(cred->user_ns, cred->euid);
 699         suid = from_kuid_munged(cred->user_ns, cred->suid);
 700 
 701         retval = put_user(ruid, ruidp);
 702         if (!retval) {
 703                 retval = put_user(euid, euidp);
 704                 if (!retval)
 705                         return put_user(suid, suidp);
 706         }
 707         return retval;
 708 }
 709 
 710 /*
 711  * Same as above, but for rgid, egid, sgid.
 712  */
 713 long __sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
 714 {
 715         struct user_namespace *ns = current_user_ns();
 716         const struct cred *old;
 717         struct cred *new;
 718         int retval;
 719         kgid_t krgid, kegid, ksgid;
 720 
 721         krgid = make_kgid(ns, rgid);
 722         kegid = make_kgid(ns, egid);
 723         ksgid = make_kgid(ns, sgid);
 724 
 725         if ((rgid != (gid_t) -1) && !gid_valid(krgid))
 726                 return -EINVAL;
 727         if ((egid != (gid_t) -1) && !gid_valid(kegid))
 728                 return -EINVAL;
 729         if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
 730                 return -EINVAL;
 731 
 732         new = prepare_creds();
 733         if (!new)
 734                 return -ENOMEM;
 735         old = current_cred();
 736 
 737         retval = -EPERM;
 738         if (!ns_capable(old->user_ns, CAP_SETGID)) {
 739                 if (rgid != (gid_t) -1        && !gid_eq(krgid, old->gid) &&
 740                     !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
 741                         goto error;
 742                 if (egid != (gid_t) -1        && !gid_eq(kegid, old->gid) &&
 743                     !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
 744                         goto error;
 745                 if (sgid != (gid_t) -1        && !gid_eq(ksgid, old->gid) &&
 746                     !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
 747                         goto error;
 748         }
 749 
 750         if (rgid != (gid_t) -1)
 751                 new->gid = krgid;
 752         if (egid != (gid_t) -1)
 753                 new->egid = kegid;
 754         if (sgid != (gid_t) -1)
 755                 new->sgid = ksgid;
 756         new->fsgid = new->egid;
 757 
 758         return commit_creds(new);
 759 
 760 error:
 761         abort_creds(new);
 762         return retval;
 763 }
 764 
 765 SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
 766 {
 767         return __sys_setresgid(rgid, egid, sgid);
 768 }
 769 
 770 SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
 771 {
 772         const struct cred *cred = current_cred();
 773         int retval;
 774         gid_t rgid, egid, sgid;
 775 
 776         rgid = from_kgid_munged(cred->user_ns, cred->gid);
 777         egid = from_kgid_munged(cred->user_ns, cred->egid);
 778         sgid = from_kgid_munged(cred->user_ns, cred->sgid);
 779 
 780         retval = put_user(rgid, rgidp);
 781         if (!retval) {
 782                 retval = put_user(egid, egidp);
 783                 if (!retval)
 784                         retval = put_user(sgid, sgidp);
 785         }
 786 
 787         return retval;
 788 }
 789 
 790 
 791 /*
 792  * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This
 793  * is used for "access()" and for the NFS daemon (letting nfsd stay at
 794  * whatever uid it wants to). It normally shadows "euid", except when
 795  * explicitly set by setfsuid() or for access..
 796  */
 797 long __sys_setfsuid(uid_t uid)
 798 {
 799         const struct cred *old;
 800         struct cred *new;
 801         uid_t old_fsuid;
 802         kuid_t kuid;
 803 
 804         old = current_cred();
 805         old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
 806 
 807         kuid = make_kuid(old->user_ns, uid);
 808         if (!uid_valid(kuid))
 809                 return old_fsuid;
 810 
 811         new = prepare_creds();
 812         if (!new)
 813                 return old_fsuid;
 814 
 815         if (uid_eq(kuid, old->uid)  || uid_eq(kuid, old->euid)  ||
 816             uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
 817             ns_capable_setid(old->user_ns, CAP_SETUID)) {
 818                 if (!uid_eq(kuid, old->fsuid)) {
 819                         new->fsuid = kuid;
 820                         if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
 821                                 goto change_okay;
 822                 }
 823         }
 824 
 825         abort_creds(new);
 826         return old_fsuid;
 827 
 828 change_okay:
 829         commit_creds(new);
 830         return old_fsuid;
 831 }
 832 
 833 SYSCALL_DEFINE1(setfsuid, uid_t, uid)
 834 {
 835         return __sys_setfsuid(uid);
 836 }
 837 
 838 /*
 839  * Samma på svenska..
 840  */
 841 long __sys_setfsgid(gid_t gid)
 842 {
 843         const struct cred *old;
 844         struct cred *new;
 845         gid_t old_fsgid;
 846         kgid_t kgid;
 847 
 848         old = current_cred();
 849         old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
 850 
 851         kgid = make_kgid(old->user_ns, gid);
 852         if (!gid_valid(kgid))
 853                 return old_fsgid;
 854 
 855         new = prepare_creds();
 856         if (!new)
 857                 return old_fsgid;
 858 
 859         if (gid_eq(kgid, old->gid)  || gid_eq(kgid, old->egid)  ||
 860             gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
 861             ns_capable(old->user_ns, CAP_SETGID)) {
 862                 if (!gid_eq(kgid, old->fsgid)) {
 863                         new->fsgid = kgid;
 864                         goto change_okay;
 865                 }
 866         }
 867 
 868         abort_creds(new);
 869         return old_fsgid;
 870 
 871 change_okay:
 872         commit_creds(new);
 873         return old_fsgid;
 874 }
 875 
 876 SYSCALL_DEFINE1(setfsgid, gid_t, gid)
 877 {
 878         return __sys_setfsgid(gid);
 879 }
 880 #endif /* CONFIG_MULTIUSER */
 881 
 882 /**
 883  * sys_getpid - return the thread group id of the current process
 884  *
 885  * Note, despite the name, this returns the tgid not the pid.  The tgid and
 886  * the pid are identical unless CLONE_THREAD was specified on clone() in
 887  * which case the tgid is the same in all threads of the same group.
 888  *
 889  * This is SMP safe as current->tgid does not change.
 890  */
 891 SYSCALL_DEFINE0(getpid)
 892 {
 893         return task_tgid_vnr(current);
 894 }
 895 
 896 /* Thread ID - the internal kernel "pid" */
 897 SYSCALL_DEFINE0(gettid)
 898 {
 899         return task_pid_vnr(current);
 900 }
 901 
 902 /*
 903  * Accessing ->real_parent is not SMP-safe, it could
 904  * change from under us. However, we can use a stale
 905  * value of ->real_parent under rcu_read_lock(), see
 906  * release_task()->call_rcu(delayed_put_task_struct).
 907  */
 908 SYSCALL_DEFINE0(getppid)
 909 {
 910         int pid;
 911 
 912         rcu_read_lock();
 913         pid = task_tgid_vnr(rcu_dereference(current->real_parent));
 914         rcu_read_unlock();
 915 
 916         return pid;
 917 }
 918 
 919 SYSCALL_DEFINE0(getuid)
 920 {
 921         /* Only we change this so SMP safe */
 922         return from_kuid_munged(current_user_ns(), current_uid());
 923 }
 924 
 925 SYSCALL_DEFINE0(geteuid)
 926 {
 927         /* Only we change this so SMP safe */
 928         return from_kuid_munged(current_user_ns(), current_euid());
 929 }
 930 
 931 SYSCALL_DEFINE0(getgid)
 932 {
 933         /* Only we change this so SMP safe */
 934         return from_kgid_munged(current_user_ns(), current_gid());
 935 }
 936 
 937 SYSCALL_DEFINE0(getegid)
 938 {
 939         /* Only we change this so SMP safe */
 940         return from_kgid_munged(current_user_ns(), current_egid());
 941 }
 942 
 943 static void do_sys_times(struct tms *tms)
 944 {
 945         u64 tgutime, tgstime, cutime, cstime;
 946 
 947         thread_group_cputime_adjusted(current, &tgutime, &tgstime);
 948         cutime = current->signal->cutime;
 949         cstime = current->signal->cstime;
 950         tms->tms_utime = nsec_to_clock_t(tgutime);
 951         tms->tms_stime = nsec_to_clock_t(tgstime);
 952         tms->tms_cutime = nsec_to_clock_t(cutime);
 953         tms->tms_cstime = nsec_to_clock_t(cstime);
 954 }
 955 
 956 SYSCALL_DEFINE1(times, struct tms __user *, tbuf)
 957 {
 958         if (tbuf) {
 959                 struct tms tmp;
 960 
 961                 do_sys_times(&tmp);
 962                 if (copy_to_user(tbuf, &tmp, sizeof(struct tms)))
 963                         return -EFAULT;
 964         }
 965         force_successful_syscall_return();
 966         return (long) jiffies_64_to_clock_t(get_jiffies_64());
 967 }
 968 
 969 #ifdef CONFIG_COMPAT
 970 static compat_clock_t clock_t_to_compat_clock_t(clock_t x)
 971 {
 972         return compat_jiffies_to_clock_t(clock_t_to_jiffies(x));
 973 }
 974 
 975 COMPAT_SYSCALL_DEFINE1(times, struct compat_tms __user *, tbuf)
 976 {
 977         if (tbuf) {
 978                 struct tms tms;
 979                 struct compat_tms tmp;
 980 
 981                 do_sys_times(&tms);
 982                 /* Convert our struct tms to the compat version. */
 983                 tmp.tms_utime = clock_t_to_compat_clock_t(tms.tms_utime);
 984                 tmp.tms_stime = clock_t_to_compat_clock_t(tms.tms_stime);
 985                 tmp.tms_cutime = clock_t_to_compat_clock_t(tms.tms_cutime);
 986                 tmp.tms_cstime = clock_t_to_compat_clock_t(tms.tms_cstime);
 987                 if (copy_to_user(tbuf, &tmp, sizeof(tmp)))
 988                         return -EFAULT;
 989         }
 990         force_successful_syscall_return();
 991         return compat_jiffies_to_clock_t(jiffies);
 992 }
 993 #endif
 994 
 995 /*
 996  * This needs some heavy checking ...
 997  * I just haven't the stomach for it. I also don't fully
 998  * understand sessions/pgrp etc. Let somebody who does explain it.
 999  *
1000  * OK, I think I have the protection semantics right.... this is really
1001  * only important on a multi-user system anyway, to make sure one user
1002  * can't send a signal to a process owned by another.  -TYT, 12/12/91
1003  *
1004  * !PF_FORKNOEXEC check to conform completely to POSIX.
1005  */
1006 SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
1007 {
1008         struct task_struct *p;
1009         struct task_struct *group_leader = current->group_leader;
1010         struct pid *pgrp;
1011         int err;
1012 
1013         if (!pid)
1014                 pid = task_pid_vnr(group_leader);
1015         if (!pgid)
1016                 pgid = pid;
1017         if (pgid < 0)
1018                 return -EINVAL;
1019         rcu_read_lock();
1020 
1021         /* From this point forward we keep holding onto the tasklist lock
1022          * so that our parent does not change from under us. -DaveM
1023          */
1024         write_lock_irq(&tasklist_lock);
1025 
1026         err = -ESRCH;
1027         p = find_task_by_vpid(pid);
1028         if (!p)
1029                 goto out;
1030 
1031         err = -EINVAL;
1032         if (!thread_group_leader(p))
1033                 goto out;
1034 
1035         if (same_thread_group(p->real_parent, group_leader)) {
1036                 err = -EPERM;
1037                 if (task_session(p) != task_session(group_leader))
1038                         goto out;
1039                 err = -EACCES;
1040                 if (!(p->flags & PF_FORKNOEXEC))
1041                         goto out;
1042         } else {
1043                 err = -ESRCH;
1044                 if (p != group_leader)
1045                         goto out;
1046         }
1047 
1048         err = -EPERM;
1049         if (p->signal->leader)
1050                 goto out;
1051 
1052         pgrp = task_pid(p);
1053         if (pgid != pid) {
1054                 struct task_struct *g;
1055 
1056                 pgrp = find_vpid(pgid);
1057                 g = pid_task(pgrp, PIDTYPE_PGID);
1058                 if (!g || task_session(g) != task_session(group_leader))
1059                         goto out;
1060         }
1061 
1062         err = security_task_setpgid(p, pgid);
1063         if (err)
1064                 goto out;
1065 
1066         if (task_pgrp(p) != pgrp)
1067                 change_pid(p, PIDTYPE_PGID, pgrp);
1068 
1069         err = 0;
1070 out:
1071         /* All paths lead to here, thus we are safe. -DaveM */
1072         write_unlock_irq(&tasklist_lock);
1073         rcu_read_unlock();
1074         return err;
1075 }
1076 
1077 static int do_getpgid(pid_t pid)
1078 {
1079         struct task_struct *p;
1080         struct pid *grp;
1081         int retval;
1082 
1083         rcu_read_lock();
1084         if (!pid)
1085                 grp = task_pgrp(current);
1086         else {
1087                 retval = -ESRCH;
1088                 p = find_task_by_vpid(pid);
1089                 if (!p)
1090                         goto out;
1091                 grp = task_pgrp(p);
1092                 if (!grp)
1093                         goto out;
1094 
1095                 retval = security_task_getpgid(p);
1096                 if (retval)
1097                         goto out;
1098         }
1099         retval = pid_vnr(grp);
1100 out:
1101         rcu_read_unlock();
1102         return retval;
1103 }
1104 
1105 SYSCALL_DEFINE1(getpgid, pid_t, pid)
1106 {
1107         return do_getpgid(pid);
1108 }
1109 
1110 #ifdef __ARCH_WANT_SYS_GETPGRP
1111 
1112 SYSCALL_DEFINE0(getpgrp)
1113 {
1114         return do_getpgid(0);
1115 }
1116 
1117 #endif
1118 
1119 SYSCALL_DEFINE1(getsid, pid_t, pid)
1120 {
1121         struct task_struct *p;
1122         struct pid *sid;
1123         int retval;
1124 
1125         rcu_read_lock();
1126         if (!pid)
1127                 sid = task_session(current);
1128         else {
1129                 retval = -ESRCH;
1130                 p = find_task_by_vpid(pid);
1131                 if (!p)
1132                         goto out;
1133                 sid = task_session(p);
1134                 if (!sid)
1135                         goto out;
1136 
1137                 retval = security_task_getsid(p);
1138                 if (retval)
1139                         goto out;
1140         }
1141         retval = pid_vnr(sid);
1142 out:
1143         rcu_read_unlock();
1144         return retval;
1145 }
1146 
1147 static void set_special_pids(struct pid *pid)
1148 {
1149         struct task_struct *curr = current->group_leader;
1150 
1151         if (task_session(curr) != pid)
1152                 change_pid(curr, PIDTYPE_SID, pid);
1153 
1154         if (task_pgrp(curr) != pid)
1155                 change_pid(curr, PIDTYPE_PGID, pid);
1156 }
1157 
1158 int ksys_setsid(void)
1159 {
1160         struct task_struct *group_leader = current->group_leader;
1161         struct pid *sid = task_pid(group_leader);
1162         pid_t session = pid_vnr(sid);
1163         int err = -EPERM;
1164 
1165         write_lock_irq(&tasklist_lock);
1166         /* Fail if I am already a session leader */
1167         if (group_leader->signal->leader)
1168                 goto out;
1169 
1170         /* Fail if a process group id already exists that equals the
1171          * proposed session id.
1172          */
1173         if (pid_task(sid, PIDTYPE_PGID))
1174                 goto out;
1175 
1176         group_leader->signal->leader = 1;
1177         set_special_pids(sid);
1178 
1179         proc_clear_tty(group_leader);
1180 
1181         err = session;
1182 out:
1183         write_unlock_irq(&tasklist_lock);
1184         if (err > 0) {
1185                 proc_sid_connector(group_leader);
1186                 sched_autogroup_create_attach(group_leader);
1187         }
1188         return err;
1189 }
1190 
1191 SYSCALL_DEFINE0(setsid)
1192 {
1193         return ksys_setsid();
1194 }
1195 
1196 DECLARE_RWSEM(uts_sem);
1197 
1198 #ifdef COMPAT_UTS_MACHINE
1199 #define override_architecture(name) \
1200         (personality(current->personality) == PER_LINUX32 && \
1201          copy_to_user(name->machine, COMPAT_UTS_MACHINE, \
1202                       sizeof(COMPAT_UTS_MACHINE)))
1203 #else
1204 #define override_architecture(name)     0
1205 #endif
1206 
1207 /*
1208  * Work around broken programs that cannot handle "Linux 3.0".
1209  * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
1210  * And we map 4.x and later versions to 2.6.60+x, so 4.0/5.0/6.0/... would be
1211  * 2.6.60.
1212  */
1213 static int override_release(char __user *release, size_t len)
1214 {
1215         int ret = 0;
1216 
1217         if (current->personality & UNAME26) {
1218                 const char *rest = UTS_RELEASE;
1219                 char buf[65] = { 0 };
1220                 int ndots = 0;
1221                 unsigned v;
1222                 size_t copy;
1223 
1224                 while (*rest) {
1225                         if (*rest == '.' && ++ndots >= 3)
1226                                 break;
1227                         if (!isdigit(*rest) && *rest != '.')
1228                                 break;
1229                         rest++;
1230                 }
1231                 v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 60;
1232                 copy = clamp_t(size_t, len, 1, sizeof(buf));
1233                 copy = scnprintf(buf, copy, "2.6.%u%s", v, rest);
1234                 ret = copy_to_user(release, buf, copy + 1);
1235         }
1236         return ret;
1237 }
1238 
1239 SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
1240 {
1241         struct new_utsname tmp;
1242 
1243         down_read(&uts_sem);
1244         memcpy(&tmp, utsname(), sizeof(tmp));
1245         up_read(&uts_sem);
1246         if (copy_to_user(name, &tmp, sizeof(tmp)))
1247                 return -EFAULT;
1248 
1249         if (override_release(name->release, sizeof(name->release)))
1250                 return -EFAULT;
1251         if (override_architecture(name))
1252                 return -EFAULT;
1253         return 0;
1254 }
1255 
1256 #ifdef __ARCH_WANT_SYS_OLD_UNAME
1257 /*
1258  * Old cruft
1259  */
1260 SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
1261 {
1262         struct old_utsname tmp;
1263 
1264         if (!name)
1265                 return -EFAULT;
1266 
1267         down_read(&uts_sem);
1268         memcpy(&tmp, utsname(), sizeof(tmp));
1269         up_read(&uts_sem);
1270         if (copy_to_user(name, &tmp, sizeof(tmp)))
1271                 return -EFAULT;
1272 
1273         if (override_release(name->release, sizeof(name->release)))
1274                 return -EFAULT;
1275         if (override_architecture(name))
1276                 return -EFAULT;
1277         return 0;
1278 }
1279 
1280 SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
1281 {
1282         struct oldold_utsname tmp = {};
1283 
1284         if (!name)
1285                 return -EFAULT;
1286 
1287         down_read(&uts_sem);
1288         memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN);
1289         memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);
1290         memcpy(&tmp.release, &utsname()->release, __OLD_UTS_LEN);
1291         memcpy(&tmp.version, &utsname()->version, __OLD_UTS_LEN);
1292         memcpy(&tmp.machine, &utsname()->machine, __OLD_UTS_LEN);
1293         up_read(&uts_sem);
1294         if (copy_to_user(name, &tmp, sizeof(tmp)))
1295                 return -EFAULT;
1296 
1297         if (override_architecture(name))
1298                 return -EFAULT;
1299         if (override_release(name->release, sizeof(name->release)))
1300                 return -EFAULT;
1301         return 0;
1302 }
1303 #endif
1304 
1305 SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
1306 {
1307         int errno;
1308         char tmp[__NEW_UTS_LEN];
1309 
1310         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1311                 return -EPERM;
1312 
1313         if (len < 0 || len > __NEW_UTS_LEN)
1314                 return -EINVAL;
1315         errno = -EFAULT;
1316         if (!copy_from_user(tmp, name, len)) {
1317                 struct new_utsname *u;
1318 
1319                 down_write(&uts_sem);
1320                 u = utsname();
1321                 memcpy(u->nodename, tmp, len);
1322                 memset(u->nodename + len, 0, sizeof(u->nodename) - len);
1323                 errno = 0;
1324                 uts_proc_notify(UTS_PROC_HOSTNAME);
1325                 up_write(&uts_sem);
1326         }
1327         return errno;
1328 }
1329 
1330 #ifdef __ARCH_WANT_SYS_GETHOSTNAME
1331 
1332 SYSCALL_DEFINE2(gethostname, char __user *, name, int, len)
1333 {
1334         int i;
1335         struct new_utsname *u;
1336         char tmp[__NEW_UTS_LEN + 1];
1337 
1338         if (len < 0)
1339                 return -EINVAL;
1340         down_read(&uts_sem);
1341         u = utsname();
1342         i = 1 + strlen(u->nodename);
1343         if (i > len)
1344                 i = len;
1345         memcpy(tmp, u->nodename, i);
1346         up_read(&uts_sem);
1347         if (copy_to_user(name, tmp, i))
1348                 return -EFAULT;
1349         return 0;
1350 }
1351 
1352 #endif
1353 
1354 /*
1355  * Only setdomainname; getdomainname can be implemented by calling
1356  * uname()
1357  */
1358 SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len)
1359 {
1360         int errno;
1361         char tmp[__NEW_UTS_LEN];
1362 
1363         if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
1364                 return -EPERM;
1365         if (len < 0 || len > __NEW_UTS_LEN)
1366                 return -EINVAL;
1367 
1368         errno = -EFAULT;
1369         if (!copy_from_user(tmp, name, len)) {
1370                 struct new_utsname *u;
1371 
1372                 down_write(&uts_sem);
1373                 u = utsname();
1374                 memcpy(u->domainname, tmp, len);
1375                 memset(u->domainname + len, 0, sizeof(u->domainname) - len);
1376                 errno = 0;
1377                 uts_proc_notify(UTS_PROC_DOMAINNAME);
1378                 up_write(&uts_sem);
1379         }
1380         return errno;
1381 }
1382 
1383 SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1384 {
1385         struct rlimit value;
1386         int ret;
1387 
1388         ret = do_prlimit(current, resource, NULL, &value);
1389         if (!ret)
1390                 ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0;
1391 
1392         return ret;
1393 }
1394 
1395 #ifdef CONFIG_COMPAT
1396 
1397 COMPAT_SYSCALL_DEFINE2(setrlimit, unsigned int, resource,
1398                        struct compat_rlimit __user *, rlim)
1399 {
1400         struct rlimit r;
1401         struct compat_rlimit r32;
1402 
1403         if (copy_from_user(&r32, rlim, sizeof(struct compat_rlimit)))
1404                 return -EFAULT;
1405 
1406         if (r32.rlim_cur == COMPAT_RLIM_INFINITY)
1407                 r.rlim_cur = RLIM_INFINITY;
1408         else
1409                 r.rlim_cur = r32.rlim_cur;
1410         if (r32.rlim_max == COMPAT_RLIM_INFINITY)
1411                 r.rlim_max = RLIM_INFINITY;
1412         else
1413                 r.rlim_max = r32.rlim_max;
1414         return do_prlimit(current, resource, &r, NULL);
1415 }
1416 
1417 COMPAT_SYSCALL_DEFINE2(getrlimit, unsigned int, resource,
1418                        struct compat_rlimit __user *, rlim)
1419 {
1420         struct rlimit r;
1421         int ret;
1422 
1423         ret = do_prlimit(current, resource, NULL, &r);
1424         if (!ret) {
1425                 struct compat_rlimit r32;
1426                 if (r.rlim_cur > COMPAT_RLIM_INFINITY)
1427                         r32.rlim_cur = COMPAT_RLIM_INFINITY;
1428                 else
1429                         r32.rlim_cur = r.rlim_cur;
1430                 if (r.rlim_max > COMPAT_RLIM_INFINITY)
1431                         r32.rlim_max = COMPAT_RLIM_INFINITY;
1432                 else
1433                         r32.rlim_max = r.rlim_max;
1434 
1435                 if (copy_to_user(rlim, &r32, sizeof(struct compat_rlimit)))
1436                         return -EFAULT;
1437         }
1438         return ret;
1439 }
1440 
1441 #endif
1442 
1443 #ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT
1444 
1445 /*
1446  *      Back compatibility for getrlimit. Needed for some apps.
1447  */
1448 SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1449                 struct rlimit __user *, rlim)
1450 {
1451         struct rlimit x;
1452         if (resource >= RLIM_NLIMITS)
1453                 return -EINVAL;
1454 
1455         resource = array_index_nospec(resource, RLIM_NLIMITS);
1456         task_lock(current->group_leader);
1457         x = current->signal->rlim[resource];
1458         task_unlock(current->group_leader);
1459         if (x.rlim_cur > 0x7FFFFFFF)
1460                 x.rlim_cur = 0x7FFFFFFF;
1461         if (x.rlim_max > 0x7FFFFFFF)
1462                 x.rlim_max = 0x7FFFFFFF;
1463         return copy_to_user(rlim, &x, sizeof(x)) ? -EFAULT : 0;
1464 }
1465 
1466 #ifdef CONFIG_COMPAT
1467 COMPAT_SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
1468                        struct compat_rlimit __user *, rlim)
1469 {
1470         struct rlimit r;
1471 
1472         if (resource >= RLIM_NLIMITS)
1473                 return -EINVAL;
1474 
1475         resource = array_index_nospec(resource, RLIM_NLIMITS);
1476         task_lock(current->group_leader);
1477         r = current->signal->rlim[resource];
1478         task_unlock(current->group_leader);
1479         if (r.rlim_cur > 0x7FFFFFFF)
1480                 r.rlim_cur = 0x7FFFFFFF;
1481         if (r.rlim_max > 0x7FFFFFFF)
1482                 r.rlim_max = 0x7FFFFFFF;
1483 
1484         if (put_user(r.rlim_cur, &rlim->rlim_cur) ||
1485             put_user(r.rlim_max, &rlim->rlim_max))
1486                 return -EFAULT;
1487         return 0;
1488 }
1489 #endif
1490 
1491 #endif
1492 
1493 static inline bool rlim64_is_infinity(__u64 rlim64)
1494 {
1495 #if BITS_PER_LONG < 64
1496         return rlim64 >= ULONG_MAX;
1497 #else
1498         return rlim64 == RLIM64_INFINITY;
1499 #endif
1500 }
1501 
1502 static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64)
1503 {
1504         if (rlim->rlim_cur == RLIM_INFINITY)
1505                 rlim64->rlim_cur = RLIM64_INFINITY;
1506         else
1507                 rlim64->rlim_cur = rlim->rlim_cur;
1508         if (rlim->rlim_max == RLIM_INFINITY)
1509                 rlim64->rlim_max = RLIM64_INFINITY;
1510         else
1511                 rlim64->rlim_max = rlim->rlim_max;
1512 }
1513 
1514 static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim)
1515 {
1516         if (rlim64_is_infinity(rlim64->rlim_cur))
1517                 rlim->rlim_cur = RLIM_INFINITY;
1518         else
1519                 rlim->rlim_cur = (unsigned long)rlim64->rlim_cur;
1520         if (rlim64_is_infinity(rlim64->rlim_max))
1521                 rlim->rlim_max = RLIM_INFINITY;
1522         else
1523                 rlim->rlim_max = (unsigned long)rlim64->rlim_max;
1524 }
1525 
1526 /* make sure you are allowed to change @tsk limits before calling this */
1527 int do_prlimit(struct task_struct *tsk, unsigned int resource,
1528                 struct rlimit *new_rlim, struct rlimit *old_rlim)
1529 {
1530         struct rlimit *rlim;
1531         int retval = 0;
1532 
1533         if (resource >= RLIM_NLIMITS)
1534                 return -EINVAL;
1535         if (new_rlim) {
1536                 if (new_rlim->rlim_cur > new_rlim->rlim_max)
1537                         return -EINVAL;
1538                 if (resource == RLIMIT_NOFILE &&
1539                                 new_rlim->rlim_max > sysctl_nr_open)
1540                         return -EPERM;
1541         }
1542 
1543         /* protect tsk->signal and tsk->sighand from disappearing */
1544         read_lock(&tasklist_lock);
1545         if (!tsk->sighand) {
1546                 retval = -ESRCH;
1547                 goto out;
1548         }
1549 
1550         rlim = tsk->signal->rlim + resource;
1551         task_lock(tsk->group_leader);
1552         if (new_rlim) {
1553                 /* Keep the capable check against init_user_ns until
1554                    cgroups can contain all limits */
1555                 if (new_rlim->rlim_max > rlim->rlim_max &&
1556                                 !capable(CAP_SYS_RESOURCE))
1557                         retval = -EPERM;
1558                 if (!retval)
1559                         retval = security_task_setrlimit(tsk, resource, new_rlim);
1560         }
1561         if (!retval) {
1562                 if (old_rlim)
1563                         *old_rlim = *rlim;
1564                 if (new_rlim)
1565                         *rlim = *new_rlim;
1566         }
1567         task_unlock(tsk->group_leader);
1568 
1569         /*
1570          * RLIMIT_CPU handling. Arm the posix CPU timer if the limit is not
1571          * infite. In case of RLIM_INFINITY the posix CPU timer code
1572          * ignores the rlimit.
1573          */
1574          if (!retval && new_rlim && resource == RLIMIT_CPU &&
1575              new_rlim->rlim_cur != RLIM_INFINITY &&
1576              IS_ENABLED(CONFIG_POSIX_TIMERS))
1577                 update_rlimit_cpu(tsk, new_rlim->rlim_cur);
1578 out:
1579         read_unlock(&tasklist_lock);
1580         return retval;
1581 }
1582 
1583 /* rcu lock must be held */
1584 static int check_prlimit_permission(struct task_struct *task,
1585                                     unsigned int flags)
1586 {
1587         const struct cred *cred = current_cred(), *tcred;
1588         bool id_match;
1589 
1590         if (current == task)
1591                 return 0;
1592 
1593         tcred = __task_cred(task);
1594         id_match = (uid_eq(cred->uid, tcred->euid) &&
1595                     uid_eq(cred->uid, tcred->suid) &&
1596                     uid_eq(cred->uid, tcred->uid)  &&
1597                     gid_eq(cred->gid, tcred->egid) &&
1598                     gid_eq(cred->gid, tcred->sgid) &&
1599                     gid_eq(cred->gid, tcred->gid));
1600         if (!id_match && !ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
1601                 return -EPERM;
1602 
1603         return security_task_prlimit(cred, tcred, flags);
1604 }
1605 
1606 SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource,
1607                 const struct rlimit64 __user *, new_rlim,
1608                 struct rlimit64 __user *, old_rlim)
1609 {
1610         struct rlimit64 old64, new64;
1611         struct rlimit old, new;
1612         struct task_struct *tsk;
1613         unsigned int checkflags = 0;
1614         int ret;
1615 
1616         if (old_rlim)
1617                 checkflags |= LSM_PRLIMIT_READ;
1618 
1619         if (new_rlim) {
1620                 if (copy_from_user(&new64, new_rlim, sizeof(new64)))
1621                         return -EFAULT;
1622                 rlim64_to_rlim(&new64, &new);
1623                 checkflags |= LSM_PRLIMIT_WRITE;
1624         }
1625 
1626         rcu_read_lock();
1627         tsk = pid ? find_task_by_vpid(pid) : current;
1628         if (!tsk) {
1629                 rcu_read_unlock();
1630                 return -ESRCH;
1631         }
1632         ret = check_prlimit_permission(tsk, checkflags);
1633         if (ret) {
1634                 rcu_read_unlock();
1635                 return ret;
1636         }
1637         get_task_struct(tsk);
1638         rcu_read_unlock();
1639 
1640         ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL,
1641                         old_rlim ? &old : NULL);
1642 
1643         if (!ret && old_rlim) {
1644                 rlim_to_rlim64(&old, &old64);
1645                 if (copy_to_user(old_rlim, &old64, sizeof(old64)))
1646                         ret = -EFAULT;
1647         }
1648 
1649         put_task_struct(tsk);
1650         return ret;
1651 }
1652 
1653 SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim)
1654 {
1655         struct rlimit new_rlim;
1656 
1657         if (copy_from_user(&new_rlim, rlim, sizeof(*rlim)))
1658                 return -EFAULT;
1659         return do_prlimit(current, resource, &new_rlim, NULL);
1660 }
1661 
1662 /*
1663  * It would make sense to put struct rusage in the task_struct,
1664  * except that would make the task_struct be *really big*.  After
1665  * task_struct gets moved into malloc'ed memory, it would
1666  * make sense to do this.  It will make moving the rest of the information
1667  * a lot simpler!  (Which we're not doing right now because we're not
1668  * measuring them yet).
1669  *
1670  * When sampling multiple threads for RUSAGE_SELF, under SMP we might have
1671  * races with threads incrementing their own counters.  But since word
1672  * reads are atomic, we either get new values or old values and we don't
1673  * care which for the sums.  We always take the siglock to protect reading
1674  * the c* fields from p->signal from races with exit.c updating those
1675  * fields when reaping, so a sample either gets all the additions of a
1676  * given child after it's reaped, or none so this sample is before reaping.
1677  *
1678  * Locking:
1679  * We need to take the siglock for CHILDEREN, SELF and BOTH
1680  * for  the cases current multithreaded, non-current single threaded
1681  * non-current multithreaded.  Thread traversal is now safe with
1682  * the siglock held.
1683  * Strictly speaking, we donot need to take the siglock if we are current and
1684  * single threaded,  as no one else can take our signal_struct away, no one
1685  * else can  reap the  children to update signal->c* counters, and no one else
1686  * can race with the signal-> fields. If we do not take any lock, the
1687  * signal-> fields could be read out of order while another thread was just
1688  * exiting. So we should  place a read memory barrier when we avoid the lock.
1689  * On the writer side,  write memory barrier is implied in  __exit_signal
1690  * as __exit_signal releases  the siglock spinlock after updating the signal->
1691  * fields. But we don't do this yet to keep things simple.
1692  *
1693  */
1694 
1695 static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r)
1696 {
1697         r->ru_nvcsw += t->nvcsw;
1698         r->ru_nivcsw += t->nivcsw;
1699         r->ru_minflt += t->min_flt;
1700         r->ru_majflt += t->maj_flt;
1701         r->ru_inblock += task_io_get_inblock(t);
1702         r->ru_oublock += task_io_get_oublock(t);
1703 }
1704 
1705 void getrusage(struct task_struct *p, int who, struct rusage *r)
1706 {
1707         struct task_struct *t;
1708         unsigned long flags;
1709         u64 tgutime, tgstime, utime, stime;
1710         unsigned long maxrss = 0;
1711 
1712         memset((char *)r, 0, sizeof (*r));
1713         utime = stime = 0;
1714 
1715         if (who == RUSAGE_THREAD) {
1716                 task_cputime_adjusted(current, &utime, &stime);
1717                 accumulate_thread_rusage(p, r);
1718                 maxrss = p->signal->maxrss;
1719                 goto out;
1720         }
1721 
1722         if (!lock_task_sighand(p, &flags))
1723                 return;
1724 
1725         switch (who) {
1726         case RUSAGE_BOTH:
1727         case RUSAGE_CHILDREN:
1728                 utime = p->signal->cutime;
1729                 stime = p->signal->cstime;
1730                 r->ru_nvcsw = p->signal->cnvcsw;
1731                 r->ru_nivcsw = p->signal->cnivcsw;
1732                 r->ru_minflt = p->signal->cmin_flt;
1733                 r->ru_majflt = p->signal->cmaj_flt;
1734                 r->ru_inblock = p->signal->cinblock;
1735                 r->ru_oublock = p->signal->coublock;
1736                 maxrss = p->signal->cmaxrss;
1737 
1738                 if (who == RUSAGE_CHILDREN)
1739                         break;
1740                 /* fall through */
1741 
1742         case RUSAGE_SELF:
1743                 thread_group_cputime_adjusted(p, &tgutime, &tgstime);
1744                 utime += tgutime;
1745                 stime += tgstime;
1746                 r->ru_nvcsw += p->signal->nvcsw;
1747                 r->ru_nivcsw += p->signal->nivcsw;
1748                 r->ru_minflt += p->signal->min_flt;
1749                 r->ru_majflt += p->signal->maj_flt;
1750                 r->ru_inblock += p->signal->inblock;
1751                 r->ru_oublock += p->signal->oublock;
1752                 if (maxrss < p->signal->maxrss)
1753                         maxrss = p->signal->maxrss;
1754                 t = p;
1755                 do {
1756                         accumulate_thread_rusage(t, r);
1757                 } while_each_thread(p, t);
1758                 break;
1759 
1760         default:
1761                 BUG();
1762         }
1763         unlock_task_sighand(p, &flags);
1764 
1765 out:
1766         r->ru_utime = ns_to_timeval(utime);
1767         r->ru_stime = ns_to_timeval(stime);
1768 
1769         if (who != RUSAGE_CHILDREN) {
1770                 struct mm_struct *mm = get_task_mm(p);
1771 
1772                 if (mm) {
1773                         setmax_mm_hiwater_rss(&maxrss, mm);
1774                         mmput(mm);
1775                 }
1776         }
1777         r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */
1778 }
1779 
1780 SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)
1781 {
1782         struct rusage r;
1783 
1784         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1785             who != RUSAGE_THREAD)
1786                 return -EINVAL;
1787 
1788         getrusage(current, who, &r);
1789         return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;
1790 }
1791 
1792 #ifdef CONFIG_COMPAT
1793 COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru)
1794 {
1795         struct rusage r;
1796 
1797         if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&
1798             who != RUSAGE_THREAD)
1799                 return -EINVAL;
1800 
1801         getrusage(current, who, &r);
1802         return put_compat_rusage(&r, ru);
1803 }
1804 #endif
1805 
1806 SYSCALL_DEFINE1(umask, int, mask)
1807 {
1808         mask = xchg(&current->fs->umask, mask & S_IRWXUGO);
1809         return mask;
1810 }
1811 
1812 static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
1813 {
1814         struct fd exe;
1815         struct file *old_exe, *exe_file;
1816         struct inode *inode;
1817         int err;
1818 
1819         exe = fdget(fd);
1820         if (!exe.file)
1821                 return -EBADF;
1822 
1823         inode = file_inode(exe.file);
1824 
1825         /*
1826          * Because the original mm->exe_file points to executable file, make
1827          * sure that this one is executable as well, to avoid breaking an
1828          * overall picture.
1829          */
1830         err = -EACCES;
1831         if (!S_ISREG(inode->i_mode) || path_noexec(&exe.file->f_path))
1832                 goto exit;
1833 
1834         err = inode_permission(inode, MAY_EXEC);
1835         if (err)
1836                 goto exit;
1837 
1838         /*
1839          * Forbid mm->exe_file change if old file still mapped.
1840          */
1841         exe_file = get_mm_exe_file(mm);
1842         err = -EBUSY;
1843         if (exe_file) {
1844                 struct vm_area_struct *vma;
1845 
1846                 down_read(&mm->mmap_sem);
1847                 for (vma = mm->mmap; vma; vma = vma->vm_next) {
1848                         if (!vma->vm_file)
1849                                 continue;
1850                         if (path_equal(&vma->vm_file->f_path,
1851                                        &exe_file->f_path))
1852                                 goto exit_err;
1853                 }
1854 
1855                 up_read(&mm->mmap_sem);
1856                 fput(exe_file);
1857         }
1858 
1859         err = 0;
1860         /* set the new file, lockless */
1861         get_file(exe.file);
1862         old_exe = xchg(&mm->exe_file, exe.file);
1863         if (old_exe)
1864                 fput(old_exe);
1865 exit:
1866         fdput(exe);
1867         return err;
1868 exit_err:
1869         up_read(&mm->mmap_sem);
1870         fput(exe_file);
1871         goto exit;
1872 }
1873 
1874 /*
1875  * Check arithmetic relations of passed addresses.
1876  *
1877  * WARNING: we don't require any capability here so be very careful
1878  * in what is allowed for modification from userspace.
1879  */
1880 static int validate_prctl_map_addr(struct prctl_mm_map *prctl_map)
1881 {
1882         unsigned long mmap_max_addr = TASK_SIZE;
1883         int error = -EINVAL, i;
1884 
1885         static const unsigned char offsets[] = {
1886                 offsetof(struct prctl_mm_map, start_code),
1887                 offsetof(struct prctl_mm_map, end_code),
1888                 offsetof(struct prctl_mm_map, start_data),
1889                 offsetof(struct prctl_mm_map, end_data),
1890                 offsetof(struct prctl_mm_map, start_brk),
1891                 offsetof(struct prctl_mm_map, brk),
1892                 offsetof(struct prctl_mm_map, start_stack),
1893                 offsetof(struct prctl_mm_map, arg_start),
1894                 offsetof(struct prctl_mm_map, arg_end),
1895                 offsetof(struct prctl_mm_map, env_start),
1896                 offsetof(struct prctl_mm_map, env_end),
1897         };
1898 
1899         /*
1900          * Make sure the members are not somewhere outside
1901          * of allowed address space.
1902          */
1903         for (i = 0; i < ARRAY_SIZE(offsets); i++) {
1904                 u64 val = *(u64 *)((char *)prctl_map + offsets[i]);
1905 
1906                 if ((unsigned long)val >= mmap_max_addr ||
1907                     (unsigned long)val < mmap_min_addr)
1908                         goto out;
1909         }
1910 
1911         /*
1912          * Make sure the pairs are ordered.
1913          */
1914 #define __prctl_check_order(__m1, __op, __m2)                           \
1915         ((unsigned long)prctl_map->__m1 __op                            \
1916          (unsigned long)prctl_map->__m2) ? 0 : -EINVAL
1917         error  = __prctl_check_order(start_code, <, end_code);
1918         error |= __prctl_check_order(start_data,<=, end_data);
1919         error |= __prctl_check_order(start_brk, <=, brk);
1920         error |= __prctl_check_order(arg_start, <=, arg_end);
1921         error |= __prctl_check_order(env_start, <=, env_end);
1922         if (error)
1923                 goto out;
1924 #undef __prctl_check_order
1925 
1926         error = -EINVAL;
1927 
1928         /*
1929          * @brk should be after @end_data in traditional maps.
1930          */
1931         if (prctl_map->start_brk <= prctl_map->end_data ||
1932             prctl_map->brk <= prctl_map->end_data)
1933                 goto out;
1934 
1935         /*
1936          * Neither we should allow to override limits if they set.
1937          */
1938         if (check_data_rlimit(rlimit(RLIMIT_DATA), prctl_map->brk,
1939                               prctl_map->start_brk, prctl_map->end_data,
1940                               prctl_map->start_data))
1941                         goto out;
1942 
1943         error = 0;
1944 out:
1945         return error;
1946 }
1947 
1948 #ifdef CONFIG_CHECKPOINT_RESTORE
1949 static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size)
1950 {
1951         struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, };
1952         unsigned long user_auxv[AT_VECTOR_SIZE];
1953         struct mm_struct *mm = current->mm;
1954         int error;
1955 
1956         BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
1957         BUILD_BUG_ON(sizeof(struct prctl_mm_map) > 256);
1958 
1959         if (opt == PR_SET_MM_MAP_SIZE)
1960                 return put_user((unsigned int)sizeof(prctl_map),
1961                                 (unsigned int __user *)addr);
1962 
1963         if (data_size != sizeof(prctl_map))
1964                 return -EINVAL;
1965 
1966         if (copy_from_user(&prctl_map, addr, sizeof(prctl_map)))
1967                 return -EFAULT;
1968 
1969         error = validate_prctl_map_addr(&prctl_map);
1970         if (error)
1971                 return error;
1972 
1973         if (prctl_map.auxv_size) {
1974                 /*
1975                  * Someone is trying to cheat the auxv vector.
1976                  */
1977                 if (!prctl_map.auxv ||
1978                                 prctl_map.auxv_size > sizeof(mm->saved_auxv))
1979                         return -EINVAL;
1980 
1981                 memset(user_auxv, 0, sizeof(user_auxv));
1982                 if (copy_from_user(user_auxv,
1983                                    (const void __user *)prctl_map.auxv,
1984                                    prctl_map.auxv_size))
1985                         return -EFAULT;
1986 
1987                 /* Last entry must be AT_NULL as specification requires */
1988                 user_auxv[AT_VECTOR_SIZE - 2] = AT_NULL;
1989                 user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL;
1990         }
1991 
1992         if (prctl_map.exe_fd != (u32)-1) {
1993                 /*
1994                  * Make sure the caller has the rights to
1995                  * change /proc/pid/exe link: only local sys admin should
1996                  * be allowed to.
1997                  */
1998                 if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
1999                         return -EINVAL;
2000 
2001                 error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd);
2002                 if (error)
2003                         return error;
2004         }
2005 
2006         /*
2007          * arg_lock protects concurent updates but we still need mmap_sem for
2008          * read to exclude races with sys_brk.
2009          */
2010         down_read(&mm->mmap_sem);
2011 
2012         /*
2013          * We don't validate if these members are pointing to
2014          * real present VMAs because application may have correspond
2015          * VMAs already unmapped and kernel uses these members for statistics
2016          * output in procfs mostly, except
2017          *
2018          *  - @start_brk/@brk which are used in do_brk but kernel lookups
2019          *    for VMAs when updating these memvers so anything wrong written
2020          *    here cause kernel to swear at userspace program but won't lead
2021          *    to any problem in kernel itself
2022          */
2023 
2024         spin_lock(&mm->arg_lock);
2025         mm->start_code  = prctl_map.start_code;
2026         mm->end_code    = prctl_map.end_code;
2027         mm->start_data  = prctl_map.start_data;
2028         mm->end_data    = prctl_map.end_data;
2029         mm->start_brk   = prctl_map.start_brk;
2030         mm->brk         = prctl_map.brk;
2031         mm->start_stack = prctl_map.start_stack;
2032         mm->arg_start   = prctl_map.arg_start;
2033         mm->arg_end     = prctl_map.arg_end;
2034         mm->env_start   = prctl_map.env_start;
2035         mm->env_end     = prctl_map.env_end;
2036         spin_unlock(&mm->arg_lock);
2037 
2038         /*
2039          * Note this update of @saved_auxv is lockless thus
2040          * if someone reads this member in procfs while we're
2041          * updating -- it may get partly updated results. It's
2042          * known and acceptable trade off: we leave it as is to
2043          * not introduce additional locks here making the kernel
2044          * more complex.
2045          */
2046         if (prctl_map.auxv_size)
2047                 memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv));
2048 
2049         up_read(&mm->mmap_sem);
2050         return 0;
2051 }
2052 #endif /* CONFIG_CHECKPOINT_RESTORE */
2053 
2054 static int prctl_set_auxv(struct mm_struct *mm, unsigned long addr,
2055                           unsigned long len)
2056 {
2057         /*
2058          * This doesn't move the auxiliary vector itself since it's pinned to
2059          * mm_struct, but it permits filling the vector with new values.  It's
2060          * up to the caller to provide sane values here, otherwise userspace
2061          * tools which use this vector might be unhappy.
2062          */
2063         unsigned long user_auxv[AT_VECTOR_SIZE];
2064 
2065         if (len > sizeof(user_auxv))
2066                 return -EINVAL;
2067 
2068         if (copy_from_user(user_auxv, (const void __user *)addr, len))
2069                 return -EFAULT;
2070 
2071         /* Make sure the last entry is always AT_NULL */
2072         user_auxv[AT_VECTOR_SIZE - 2] = 0;
2073         user_auxv[AT_VECTOR_SIZE - 1] = 0;
2074 
2075         BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv));
2076 
2077         task_lock(current);
2078         memcpy(mm->saved_auxv, user_auxv, len);
2079         task_unlock(current);
2080 
2081         return 0;
2082 }
2083 
2084 static int prctl_set_mm(int opt, unsigned long addr,
2085                         unsigned long arg4, unsigned long arg5)
2086 {
2087         struct mm_struct *mm = current->mm;
2088         struct prctl_mm_map prctl_map = {
2089                 .auxv = NULL,
2090                 .auxv_size = 0,
2091                 .exe_fd = -1,
2092         };
2093         struct vm_area_struct *vma;
2094         int error;
2095 
2096         if (arg5 || (arg4 && (opt != PR_SET_MM_AUXV &&
2097                               opt != PR_SET_MM_MAP &&
2098                               opt != PR_SET_MM_MAP_SIZE)))
2099                 return -EINVAL;
2100 
2101 #ifdef CONFIG_CHECKPOINT_RESTORE
2102         if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE)
2103                 return prctl_set_mm_map(opt, (const void __user *)addr, arg4);
2104 #endif
2105 
2106         if (!capable(CAP_SYS_RESOURCE))
2107                 return -EPERM;
2108 
2109         if (opt == PR_SET_MM_EXE_FILE)
2110                 return prctl_set_mm_exe_file(mm, (unsigned int)addr);
2111 
2112         if (opt == PR_SET_MM_AUXV)
2113                 return prctl_set_auxv(mm, addr, arg4);
2114 
2115         if (addr >= TASK_SIZE || addr < mmap_min_addr)
2116                 return -EINVAL;
2117 
2118         error = -EINVAL;
2119 
2120         /*
2121          * arg_lock protects concurent updates of arg boundaries, we need
2122          * mmap_sem for a) concurrent sys_brk, b) finding VMA for addr
2123          * validation.
2124          */
2125         down_read(&mm->mmap_sem);
2126         vma = find_vma(mm, addr);
2127 
2128         spin_lock(&mm->arg_lock);
2129         prctl_map.start_code    = mm->start_code;
2130         prctl_map.end_code      = mm->end_code;
2131         prctl_map.start_data    = mm->start_data;
2132         prctl_map.end_data      = mm->end_data;
2133         prctl_map.start_brk     = mm->start_brk;
2134         prctl_map.brk           = mm->brk;
2135         prctl_map.start_stack   = mm->start_stack;
2136         prctl_map.arg_start     = mm->arg_start;
2137         prctl_map.arg_end       = mm->arg_end;
2138         prctl_map.env_start     = mm->env_start;
2139         prctl_map.env_end       = mm->env_end;
2140 
2141         switch (opt) {
2142         case PR_SET_MM_START_CODE:
2143                 prctl_map.start_code = addr;
2144                 break;
2145         case PR_SET_MM_END_CODE:
2146                 prctl_map.end_code = addr;
2147                 break;
2148         case PR_SET_MM_START_DATA:
2149                 prctl_map.start_data = addr;
2150                 break;
2151         case PR_SET_MM_END_DATA:
2152                 prctl_map.end_data = addr;
2153                 break;
2154         case PR_SET_MM_START_STACK:
2155                 prctl_map.start_stack = addr;
2156                 break;
2157         case PR_SET_MM_START_BRK:
2158                 prctl_map.start_brk = addr;
2159                 break;
2160         case PR_SET_MM_BRK:
2161                 prctl_map.brk = addr;
2162                 break;
2163         case PR_SET_MM_ARG_START:
2164                 prctl_map.arg_start = addr;
2165                 break;
2166         case PR_SET_MM_ARG_END:
2167                 prctl_map.arg_end = addr;
2168                 break;
2169         case PR_SET_MM_ENV_START:
2170                 prctl_map.env_start = addr;
2171                 break;
2172         case PR_SET_MM_ENV_END:
2173                 prctl_map.env_end = addr;
2174                 break;
2175         default:
2176                 goto out;
2177         }
2178 
2179         error = validate_prctl_map_addr(&prctl_map);
2180         if (error)
2181                 goto out;
2182 
2183         switch (opt) {
2184         /*
2185          * If command line arguments and environment
2186          * are placed somewhere else on stack, we can
2187          * set them up here, ARG_START/END to setup
2188          * command line argumets and ENV_START/END
2189          * for environment.
2190          */
2191         case PR_SET_MM_START_STACK:
2192         case PR_SET_MM_ARG_START:
2193         case PR_SET_MM_ARG_END:
2194         case PR_SET_MM_ENV_START:
2195         case PR_SET_MM_ENV_END:
2196                 if (!vma) {
2197                         error = -EFAULT;
2198                         goto out;
2199                 }
2200         }
2201 
2202         mm->start_code  = prctl_map.start_code;
2203         mm->end_code    = prctl_map.end_code;
2204         mm->start_data  = prctl_map.start_data;
2205         mm->end_data    = prctl_map.end_data;
2206         mm->start_brk   = prctl_map.start_brk;
2207         mm->brk         = prctl_map.brk;
2208         mm->start_stack = prctl_map.start_stack;
2209         mm->arg_start   = prctl_map.arg_start;
2210         mm->arg_end     = prctl_map.arg_end;
2211         mm->env_start   = prctl_map.env_start;
2212         mm->env_end     = prctl_map.env_end;
2213 
2214         error = 0;
2215 out:
2216         spin_unlock(&mm->arg_lock);
2217         up_read(&mm->mmap_sem);
2218         return error;
2219 }
2220 
2221 #ifdef CONFIG_CHECKPOINT_RESTORE
2222 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
2223 {
2224         return put_user(me->clear_child_tid, tid_addr);
2225 }
2226 #else
2227 static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
2228 {
2229         return -EINVAL;
2230 }
2231 #endif
2232 
2233 static int propagate_has_child_subreaper(struct task_struct *p, void *data)
2234 {
2235         /*
2236          * If task has has_child_subreaper - all its decendants
2237          * already have these flag too and new decendants will
2238          * inherit it on fork, skip them.
2239          *
2240          * If we've found child_reaper - skip descendants in
2241          * it's subtree as they will never get out pidns.
2242          */
2243         if (p->signal->has_child_subreaper ||
2244             is_child_reaper(task_pid(p)))
2245                 return 0;
2246 
2247         p->signal->has_child_subreaper = 1;
2248         return 1;
2249 }
2250 
2251 int __weak arch_prctl_spec_ctrl_get(struct task_struct *t, unsigned long which)
2252 {
2253         return -EINVAL;
2254 }
2255 
2256 int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
2257                                     unsigned long ctrl)
2258 {
2259         return -EINVAL;
2260 }
2261 
2262 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
2263                 unsigned long, arg4, unsigned long, arg5)
2264 {
2265         struct task_struct *me = current;
2266         unsigned char comm[sizeof(me->comm)];
2267         long error;
2268 
2269         error = security_task_prctl(option, arg2, arg3, arg4, arg5);
2270         if (error != -ENOSYS)
2271                 return error;
2272 
2273         error = 0;
2274         switch (option) {
2275         case PR_SET_PDEATHSIG:
2276                 if (!valid_signal(arg2)) {
2277                         error = -EINVAL;
2278                         break;
2279                 }
2280                 me->pdeath_signal = arg2;
2281                 break;
2282         case PR_GET_PDEATHSIG:
2283                 error = put_user(me->pdeath_signal, (int __user *)arg2);
2284                 break;
2285         case PR_GET_DUMPABLE:
2286                 error = get_dumpable(me->mm);
2287                 break;
2288         case PR_SET_DUMPABLE:
2289                 if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) {
2290                         error = -EINVAL;
2291                         break;
2292                 }
2293                 set_dumpable(me->mm, arg2);
2294                 break;
2295 
2296         case PR_SET_UNALIGN:
2297                 error = SET_UNALIGN_CTL(me, arg2);
2298                 break;
2299         case PR_GET_UNALIGN:
2300                 error = GET_UNALIGN_CTL(me, arg2);
2301                 break;
2302         case PR_SET_FPEMU:
2303                 error = SET_FPEMU_CTL(me, arg2);
2304                 break;
2305         case PR_GET_FPEMU:
2306                 error = GET_FPEMU_CTL(me, arg2);
2307                 break;
2308         case PR_SET_FPEXC:
2309                 error = SET_FPEXC_CTL(me, arg2);
2310                 break;
2311         case PR_GET_FPEXC:
2312                 error = GET_FPEXC_CTL(me, arg2);
2313                 break;
2314         case PR_GET_TIMING:
2315                 error = PR_TIMING_STATISTICAL;
2316                 break;
2317         case PR_SET_TIMING:
2318                 if (arg2 != PR_TIMING_STATISTICAL)
2319                         error = -EINVAL;
2320                 break;
2321         case PR_SET_NAME:
2322                 comm[sizeof(me->comm) - 1] = 0;
2323                 if (strncpy_from_user(comm, (char __user *)arg2,
2324                                       sizeof(me->comm) - 1) < 0)
2325                         return -EFAULT;
2326                 set_task_comm(me, comm);
2327                 proc_comm_connector(me);
2328                 break;
2329         case PR_GET_NAME:
2330                 get_task_comm(comm, me);
2331                 if (copy_to_user((char __user *)arg2, comm, sizeof(comm)))
2332                         return -EFAULT;
2333                 break;
2334         case PR_GET_ENDIAN:
2335                 error = GET_ENDIAN(me, arg2);
2336                 break;
2337         case PR_SET_ENDIAN:
2338                 error = SET_ENDIAN(me, arg2);
2339                 break;
2340         case PR_GET_SECCOMP:
2341                 error = prctl_get_seccomp();
2342                 break;
2343         case PR_SET_SECCOMP:
2344                 error = prctl_set_seccomp(arg2, (char __user *)arg3);
2345                 break;
2346         case PR_GET_TSC:
2347                 error = GET_TSC_CTL(arg2);
2348                 break;
2349         case PR_SET_TSC:
2350                 error = SET_TSC_CTL(arg2);
2351                 break;
2352         case PR_TASK_PERF_EVENTS_DISABLE:
2353                 error = perf_event_task_disable();
2354                 break;
2355         case PR_TASK_PERF_EVENTS_ENABLE:
2356                 error = perf_event_task_enable();
2357                 break;
2358         case PR_GET_TIMERSLACK:
2359                 if (current->timer_slack_ns > ULONG_MAX)
2360                         error = ULONG_MAX;
2361                 else
2362                         error = current->timer_slack_ns;
2363                 break;
2364         case PR_SET_TIMERSLACK:
2365                 if (arg2 <= 0)
2366                         current->timer_slack_ns =
2367                                         current->default_timer_slack_ns;
2368                 else
2369                         current->timer_slack_ns = arg2;
2370                 break;
2371         case PR_MCE_KILL:
2372                 if (arg4 | arg5)
2373                         return -EINVAL;
2374                 switch (arg2) {
2375                 case PR_MCE_KILL_CLEAR:
2376                         if (arg3 != 0)
2377                                 return -EINVAL;
2378                         current->flags &= ~PF_MCE_PROCESS;
2379                         break;
2380                 case PR_MCE_KILL_SET:
2381                         current->flags |= PF_MCE_PROCESS;
2382                         if (arg3 == PR_MCE_KILL_EARLY)
2383                                 current->flags |= PF_MCE_EARLY;
2384                         else if (arg3 == PR_MCE_KILL_LATE)
2385                                 current->flags &= ~PF_MCE_EARLY;
2386                         else if (arg3 == PR_MCE_KILL_DEFAULT)
2387                                 current->flags &=
2388                                                 ~(PF_MCE_EARLY|PF_MCE_PROCESS);
2389                         else
2390                                 return -EINVAL;
2391                         break;
2392                 default:
2393                         return -EINVAL;
2394                 }
2395                 break;
2396         case PR_MCE_KILL_GET:
2397                 if (arg2 | arg3 | arg4 | arg5)
2398                         return -EINVAL;
2399                 if (current->flags & PF_MCE_PROCESS)
2400                         error = (current->flags & PF_MCE_EARLY) ?
2401                                 PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE;
2402                 else
2403                         error = PR_MCE_KILL_DEFAULT;
2404                 break;
2405         case PR_SET_MM:
2406                 error = prctl_set_mm(arg2, arg3, arg4, arg5);
2407                 break;
2408         case PR_GET_TID_ADDRESS:
2409                 error = prctl_get_tid_address(me, (int __user **)arg2);
2410                 break;
2411         case PR_SET_CHILD_SUBREAPER:
2412                 me->signal->is_child_subreaper = !!arg2;
2413                 if (!arg2)
2414                         break;
2415 
2416                 walk_process_tree(me, propagate_has_child_subreaper, NULL);
2417                 break;
2418         case PR_GET_CHILD_SUBREAPER:
2419                 error = put_user(me->signal->is_child_subreaper,
2420                                  (int __user *)arg2);
2421                 break;
2422         case PR_SET_NO_NEW_PRIVS:
2423                 if (arg2 != 1 || arg3 || arg4 || arg5)
2424                         return -EINVAL;
2425 
2426                 task_set_no_new_privs(current);
2427                 break;
2428         case PR_GET_NO_NEW_PRIVS:
2429                 if (arg2 || arg3 || arg4 || arg5)
2430                         return -EINVAL;
2431                 return task_no_new_privs(current) ? 1 : 0;
2432         case PR_GET_THP_DISABLE:
2433                 if (arg2 || arg3 || arg4 || arg5)
2434                         return -EINVAL;
2435                 error = !!test_bit(MMF_DISABLE_THP, &me->mm->flags);
2436                 break;
2437         case PR_SET_THP_DISABLE:
2438                 if (arg3 || arg4 || arg5)
2439                         return -EINVAL;
2440                 if (down_write_killable(&me->mm->mmap_sem))
2441                         return -EINTR;
2442                 if (arg2)
2443                         set_bit(MMF_DISABLE_THP, &me->mm->flags);
2444                 else
2445                         clear_bit(MMF_DISABLE_THP, &me->mm->flags);
2446                 up_write(&me->mm->mmap_sem);
2447                 break;
2448         case PR_MPX_ENABLE_MANAGEMENT:
2449         case PR_MPX_DISABLE_MANAGEMENT:
2450                 /* No longer implemented: */
2451                 return -EINVAL;
2452         case PR_SET_FP_MODE:
2453                 error = SET_FP_MODE(me, arg2);
2454                 break;
2455         case PR_GET_FP_MODE:
2456                 error = GET_FP_MODE(me);
2457                 break;
2458         case PR_SVE_SET_VL:
2459                 error = SVE_SET_VL(arg2);
2460                 break;
2461         case PR_SVE_GET_VL:
2462                 error = SVE_GET_VL();
2463                 break;
2464         case PR_GET_SPECULATION_CTRL:
2465                 if (arg3 || arg4 || arg5)
2466                         return -EINVAL;
2467                 error = arch_prctl_spec_ctrl_get(me, arg2);
2468                 break;
2469         case PR_SET_SPECULATION_CTRL:
2470                 if (arg4 || arg5)
2471                         return -EINVAL;
2472                 error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
2473                 break;
2474         case PR_PAC_RESET_KEYS:
2475                 if (arg3 || arg4 || arg5)
2476                         return -EINVAL;
2477                 error = PAC_RESET_KEYS(me, arg2);
2478                 break;
2479         case PR_SET_TAGGED_ADDR_CTRL:
2480                 if (arg3 || arg4 || arg5)
2481                         return -EINVAL;
2482                 error = SET_TAGGED_ADDR_CTRL(arg2);
2483                 break;
2484         case PR_GET_TAGGED_ADDR_CTRL:
2485                 if (arg2 || arg3 || arg4 || arg5)
2486                         return -EINVAL;
2487                 error = GET_TAGGED_ADDR_CTRL();
2488                 break;
2489         default:
2490                 error = -EINVAL;
2491                 break;
2492         }
2493         return error;
2494 }
2495 
2496 SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep,
2497                 struct getcpu_cache __user *, unused)
2498 {
2499         int err = 0;
2500         int cpu = raw_smp_processor_id();
2501 
2502         if (cpup)
2503                 err |= put_user(cpu, cpup);
2504         if (nodep)
2505                 err |= put_user(cpu_to_node(cpu), nodep);
2506         return err ? -EFAULT : 0;
2507 }
2508 
2509 /**
2510  * do_sysinfo - fill in sysinfo struct
2511  * @info: pointer to buffer to fill
2512  */
2513 static int do_sysinfo(struct sysinfo *info)
2514 {
2515         unsigned long mem_total, sav_total;
2516         unsigned int mem_unit, bitcount;
2517         struct timespec64 tp;
2518 
2519         memset(info, 0, sizeof(struct sysinfo));
2520 
2521         ktime_get_boottime_ts64(&tp);
2522         info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);
2523 
2524         get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);
2525 
2526         info->procs = nr_threads;
2527 
2528         si_meminfo(info);
2529         si_swapinfo(info);
2530 
2531         /*
2532          * If the sum of all the available memory (i.e. ram + swap)
2533          * is less than can be stored in a 32 bit unsigned long then
2534          * we can be binary compatible with 2.2.x kernels.  If not,
2535          * well, in that case 2.2.x was broken anyways...
2536          *
2537          *  -Erik Andersen <andersee@debian.org>
2538          */
2539 
2540         mem_total = info->totalram + info->totalswap;
2541         if (mem_total < info->totalram || mem_total < info->totalswap)
2542                 goto out;
2543         bitcount = 0;
2544         mem_unit = info->mem_unit;
2545         while (mem_unit > 1) {
2546                 bitcount++;
2547                 mem_unit >>= 1;
2548                 sav_total = mem_total;
2549                 mem_total <<= 1;
2550                 if (mem_total < sav_total)
2551                         goto out;
2552         }
2553 
2554         /*
2555          * If mem_total did not overflow, multiply all memory values by
2556          * info->mem_unit and set it to 1.  This leaves things compatible
2557          * with 2.2.x, and also retains compatibility with earlier 2.4.x
2558          * kernels...
2559          */
2560 
2561         info->mem_unit = 1;
2562         info->totalram <<= bitcount;
2563         info->freeram <<= bitcount;
2564         info->sharedram <<= bitcount;
2565         info->bufferram <<= bitcount;
2566         info->totalswap <<= bitcount;
2567         info->freeswap <<= bitcount;
2568         info->totalhigh <<= bitcount;
2569         info->freehigh <<= bitcount;
2570 
2571 out:
2572         return 0;
2573 }
2574 
2575 SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
2576 {
2577         struct sysinfo val;
2578 
2579         do_sysinfo(&val);
2580 
2581         if (copy_to_user(info, &val, sizeof(struct sysinfo)))
2582                 return -EFAULT;
2583 
2584         return 0;
2585 }
2586 
2587 #ifdef CONFIG_COMPAT
2588 struct compat_sysinfo {
2589         s32 uptime;
2590         u32 loads[3];
2591         u32 totalram;
2592         u32 freeram;
2593         u32 sharedram;
2594         u32 bufferram;
2595         u32 totalswap;
2596         u32 freeswap;
2597         u16 procs;
2598         u16 pad;
2599         u32 totalhigh;
2600         u32 freehigh;
2601         u32 mem_unit;
2602         char _f[20-2*sizeof(u32)-sizeof(int)];
2603 };
2604 
2605 COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info)
2606 {
2607         struct sysinfo s;
2608 
2609         do_sysinfo(&s);
2610 
2611         /* Check to see if any memory value is too large for 32-bit and scale
2612          *  down if needed
2613          */
2614         if (upper_32_bits(s.totalram) || upper_32_bits(s.totalswap)) {
2615                 int bitcount = 0;
2616 
2617                 while (s.mem_unit < PAGE_SIZE) {
2618                         s.mem_unit <<= 1;
2619                         bitcount++;
2620                 }
2621 
2622                 s.totalram >>= bitcount;
2623                 s.freeram >>= bitcount;
2624                 s.sharedram >>= bitcount;
2625                 s.bufferram >>= bitcount;
2626                 s.totalswap >>= bitcount;
2627                 s.freeswap >>= bitcount;
2628                 s.totalhigh >>= bitcount;
2629                 s.freehigh >>= bitcount;
2630         }
2631 
2632         if (!access_ok(info, sizeof(struct compat_sysinfo)) ||
2633             __put_user(s.uptime, &info->uptime) ||
2634             __put_user(s.loads[0], &info->loads[0]) ||
2635             __put_user(s.loads[1], &info->loads[1]) ||
2636             __put_user(s.loads[2], &info->loads[2]) ||
2637             __put_user(s.totalram, &info->totalram) ||
2638             __put_user(s.freeram, &info->freeram) ||
2639             __put_user(s.sharedram, &info->sharedram) ||
2640             __put_user(s.bufferram, &info->bufferram) ||
2641             __put_user(s.totalswap, &info->totalswap) ||
2642             __put_user(s.freeswap, &info->freeswap) ||
2643             __put_user(s.procs, &info->procs) ||
2644             __put_user(s.totalhigh, &info->totalhigh) ||
2645             __put_user(s.freehigh, &info->freehigh) ||
2646             __put_user(s.mem_unit, &info->mem_unit))
2647                 return -EFAULT;
2648 
2649         return 0;
2650 }
2651 #endif /* CONFIG_COMPAT */
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root/kernel/sys.c

DEFINITIONS
