security/commoncap.c

   1 /* Common capabilities, needed by capability.o and root_plug.o
   2  *
   3  *      This program is free software; you can redistribute it and/or modify
   4  *      it under the terms of the GNU General Public License as published by
   5  *      the Free Software Foundation; either version 2 of the License, or
   6  *      (at your option) any later version.
   7  *
   8  */
   9
  10 #include <linux/capability.h>
  11 #include <linux/audit.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/security.h>
  16 #include <linux/file.h>
  17 #include <linux/mm.h>
  18 #include <linux/mman.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/swap.h>
  21 #include <linux/skbuff.h>
  22 #include <linux/netlink.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/xattr.h>
  25 #include <linux/hugetlb.h>
  26 #include <linux/mount.h>
  27 #include <linux/sched.h>
  28 #include <linux/prctl.h>
  29 #include <linux/securebits.h>
  30
  31 int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
  32 {
  33         NETLINK_CB(skb).eff_cap = current->cap_effective;
  34         return 0;
  35 }
  36
  37 int cap_netlink_recv(struct sk_buff *skb, int cap)
  38 {
  39         if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))
  40                 return -EPERM;
  41         return 0;
  42 }
  43
  44 EXPORT_SYMBOL(cap_netlink_recv);
  45
  46 /*
  47  * NOTE WELL: cap_capable() cannot be used like the kernel's capable()
  48  * function.  That is, it has the reverse semantics: cap_capable()
  49  * returns 0 when a task has a capability, but the kernel's capable()
  50  * returns 1 for this case.
  51  */
  52 int cap_capable(struct task_struct *tsk, int cap, int audit)
  53 {
  54         /* Derived from include/linux/sched.h:capable. */
  55         if (cap_raised(tsk->cap_effective, cap))
  56                 return 0;
  57         return -EPERM;
  58 }
  59
  60 int cap_settime(struct timespec *ts, struct timezone *tz)
  61 {
  62         if (!capable(CAP_SYS_TIME))
  63                 return -EPERM;
  64         return 0;
  65 }
  66
  67 int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
  68 {
  69         /* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
  70         if (cap_issubset(child->cap_permitted, current->cap_permitted))
  71                 return 0;
  72         if (capable(CAP_SYS_PTRACE))
  73                 return 0;
  74         return -EPERM;
  75 }
  76
  77 int cap_ptrace_traceme(struct task_struct *parent)
  78 {
  79         /* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
  80         if (cap_issubset(current->cap_permitted, parent->cap_permitted))
  81                 return 0;
  82         if (has_capability(parent, CAP_SYS_PTRACE))
  83                 return 0;
  84         return -EPERM;
  85 }
  86
  87 int cap_capget (struct task_struct *target, kernel_cap_t *effective,
  88                 kernel_cap_t *inheritable, kernel_cap_t *permitted)
  89 {
  90         /* Derived from kernel/capability.c:sys_capget. */
  91         *effective = target->cap_effective;
  92         *inheritable = target->cap_inheritable;
  93         *permitted = target->cap_permitted;
  94         return 0;
  95 }
  96
  97 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
  98
  99 static inline int cap_inh_is_capped(void)
 100 {
 101         /*
 102          * Return 1 if changes to the inheritable set are limited
 103          * to the old permitted set. That is, if the current task
 104          * does *not* possess the CAP_SETPCAP capability.
 105          */
 106         return (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0);
 107 }
 108
 109 static inline int cap_limit_ptraced_target(void) { return 1; }
 110
 111 #else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
 112
 113 static inline int cap_inh_is_capped(void) { return 1; }
 114 static inline int cap_limit_ptraced_target(void)
 115 {
 116         return !capable(CAP_SETPCAP);
 117 }
 118
 119 #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
 120
 121 int cap_capset_check (kernel_cap_t *effective,
 122                       kernel_cap_t *inheritable, kernel_cap_t *permitted)
 123 {
 124         if (cap_inh_is_capped()
 125             && !cap_issubset(*inheritable,
 126                              cap_combine(current->cap_inheritable,
 127                                          current->cap_permitted))) {
 128                 /* incapable of using this inheritable set */
 129                 return -EPERM;
 130         }
 131         if (!cap_issubset(*inheritable,
 132                            cap_combine(current->cap_inheritable,
 133                                        current->cap_bset))) {
 134                 /* no new pI capabilities outside bounding set */
 135                 return -EPERM;
 136         }
 137
 138         /* verify restrictions on target's new Permitted set */
 139         if (!cap_issubset (*permitted,
 140                            cap_combine (current->cap_permitted,
 141                                         current->cap_permitted))) {
 142                 return -EPERM;
 143         }
 144
 145         /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
 146         if (!cap_issubset (*effective, *permitted)) {
 147                 return -EPERM;
 148         }
 149
 150         return 0;
 151 }
 152
 153 void cap_capset_set (kernel_cap_t *effective,
 154                      kernel_cap_t *inheritable, kernel_cap_t *permitted)
 155 {
 156         current->cap_effective = *effective;
 157         current->cap_inheritable = *inheritable;
 158         current->cap_permitted = *permitted;
 159 }
 160
 161 static inline void bprm_clear_caps(struct linux_binprm *bprm)
 162 {
 163         cap_clear(bprm->cap_post_exec_permitted);
 164         bprm->cap_effective = false;
 165 }
 166
 167 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 168
 169 int cap_inode_need_killpriv(struct dentry *dentry)
 170 {
 171         struct inode *inode = dentry->d_inode;
 172         int error;
 173
 174         if (!inode->i_op || !inode->i_op->getxattr)
 175                return 0;
 176
 177         error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
 178         if (error <= 0)
 179                 return 0;
 180         return 1;
 181 }
 182
 183 int cap_inode_killpriv(struct dentry *dentry)
 184 {
 185         struct inode *inode = dentry->d_inode;
 186
 187         if (!inode->i_op || !inode->i_op->removexattr)
 188                return 0;
 189
 190         return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
 191 }
 192
 193 static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
 194                                           struct linux_binprm *bprm)
 195 {
 196         unsigned i;
 197         int ret = 0;
 198
 199         if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
 200                 bprm->cap_effective = true;
 201         else
 202                 bprm->cap_effective = false;
 203
 204         CAP_FOR_EACH_U32(i) {
 205                 __u32 permitted = caps->permitted.cap[i];
 206                 __u32 inheritable = caps->inheritable.cap[i];
 207
 208                 /*
 209                  * pP' = (X & fP) | (pI & fI)
 210                  */
 211                 bprm->cap_post_exec_permitted.cap[i] =
 212                         (current->cap_bset.cap[i] & permitted) |
 213                         (current->cap_inheritable.cap[i] & inheritable);
 214
 215                 if (permitted & ~bprm->cap_post_exec_permitted.cap[i]) {
 216                         /*
 217                          * insufficient to execute correctly
 218                          */
 219                         ret = -EPERM;
 220                 }
 221         }
 222
 223         /*
 224          * For legacy apps, with no internal support for recognizing they
 225          * do not have enough capabilities, we return an error if they are
 226          * missing some "forced" (aka file-permitted) capabilities.
 227          */
 228         return bprm->cap_effective ? ret : 0;
 229 }
 230
 231 int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
 232 {
 233         struct inode *inode = dentry->d_inode;
 234         __u32 magic_etc;
 235         unsigned tocopy, i;
 236         int size;
 237         struct vfs_cap_data caps;
 238
 239         memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
 240
 241         if (!inode || !inode->i_op || !inode->i_op->getxattr)
 242                 return -ENODATA;
 243
 244         size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps,
 245                                    XATTR_CAPS_SZ);
 246         if (size == -ENODATA || size == -EOPNOTSUPP) {
 247                 /* no data, that's ok */
 248                 return -ENODATA;
 249         }
 250         if (size < 0)
 251                 return size;
 252
 253         if (size < sizeof(magic_etc))
 254                 return -EINVAL;
 255
 256         cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc);
 257
 258         switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
 259         case VFS_CAP_REVISION_1:
 260                 if (size != XATTR_CAPS_SZ_1)
 261                         return -EINVAL;
 262                 tocopy = VFS_CAP_U32_1;
 263                 break;
 264         case VFS_CAP_REVISION_2:
 265                 if (size != XATTR_CAPS_SZ_2)
 266                         return -EINVAL;
 267                 tocopy = VFS_CAP_U32_2;
 268                 break;
 269         default:
 270                 return -EINVAL;
 271         }
 272
 273         CAP_FOR_EACH_U32(i) {
 274                 if (i >= tocopy)
 275                         break;
 276                 cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted);
 277                 cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable);
 278         }
 279         return 0;
 280 }
 281
 282 /* Locate any VFS capabilities: */
 283 static int get_file_caps(struct linux_binprm *bprm)
 284 {
 285         struct dentry *dentry;
 286         int rc = 0;
 287         struct cpu_vfs_cap_data vcaps;
 288
 289         bprm_clear_caps(bprm);
 290
 291         if (!file_caps_enabled)
 292                 return 0;
 293
 294         if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)
 295                 return 0;
 296
 297         dentry = dget(bprm->file->f_dentry);
 298
 299         rc = get_vfs_caps_from_disk(dentry, &vcaps);
 300         if (rc < 0) {
 301                 if (rc == -EINVAL)
 302                         printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n",
 303                                 __func__, rc, bprm->filename);
 304                 else if (rc == -ENODATA)
 305                         rc = 0;
 306                 goto out;
 307         }
 308
 309         rc = bprm_caps_from_vfs_caps(&vcaps, bprm);
 310
 311 out:
 312         dput(dentry);
 313         if (rc)
 314                 bprm_clear_caps(bprm);
 315
 316         return rc;
 317 }
 318
 319 #else
 320 int cap_inode_need_killpriv(struct dentry *dentry)
 321 {
 322         return 0;
 323 }
 324
 325 int cap_inode_killpriv(struct dentry *dentry)
 326 {
 327         return 0;
 328 }
 329
 330 static inline int get_file_caps(struct linux_binprm *bprm)
 331 {
 332         bprm_clear_caps(bprm);
 333         return 0;
 334 }
 335 #endif
 336
 337 int cap_bprm_set_security (struct linux_binprm *bprm)
 338 {
 339         int ret;
 340
 341         ret = get_file_caps(bprm);
 342
 343         if (!issecure(SECURE_NOROOT)) {
 344                 /*
 345                  * To support inheritance of root-permissions and suid-root
 346                  * executables under compatibility mode, we override the
 347                  * capability sets for the file.
 348                  *
 349                  * If only the real uid is 0, we do not set the effective
 350                  * bit.
 351                  */
 352                 if (bprm->e_uid == 0 || current_uid() == 0) {
 353                         /* pP' = (cap_bset & ~0) | (pI & ~0) */
 354                         bprm->cap_post_exec_permitted = cap_combine(
 355                                 current->cap_bset, current->cap_inheritable
 356                                 );
 357                         bprm->cap_effective = (bprm->e_uid == 0);
 358                         ret = 0;
 359                 }
 360         }
 361
 362         return ret;
 363 }
 364
 365 void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
 366 {
 367         kernel_cap_t pP = current->cap_permitted;
 368         kernel_cap_t pE = current->cap_effective;
 369         uid_t uid;
 370         gid_t gid;
 371
 372         current_uid_gid(&uid, &gid);
 373
 374         if (bprm->e_uid != uid || bprm->e_gid != gid ||
 375             !cap_issubset(bprm->cap_post_exec_permitted,
 376                           current->cap_permitted)) {
 377                 set_dumpable(current->mm, suid_dumpable);
 378                 current->pdeath_signal = 0;
 379
 380                 if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
 381                         if (!capable(CAP_SETUID)) {
 382                                 bprm->e_uid = uid;
 383                                 bprm->e_gid = gid;
 384                         }
 385                         if (cap_limit_ptraced_target()) {
 386                                 bprm->cap_post_exec_permitted = cap_intersect(
 387                                         bprm->cap_post_exec_permitted,
 388                                         current->cap_permitted);
 389                         }
 390                 }
 391         }
 392
 393         current->suid = current->euid = current->fsuid = bprm->e_uid;
 394         current->sgid = current->egid = current->fsgid = bprm->e_gid;
 395
 396         /* For init, we want to retain the capabilities set
 397          * in the init_task struct. Thus we skip the usual
 398          * capability rules */
 399         if (!is_global_init(current)) {
 400                 current->cap_permitted = bprm->cap_post_exec_permitted;
 401                 if (bprm->cap_effective)
 402                         current->cap_effective = bprm->cap_post_exec_permitted;
 403                 else
 404                         cap_clear(current->cap_effective);
 405         }
 406
 407         /*
 408          * Audit candidate if current->cap_effective is set
 409          *
 410          * We do not bother to audit if 3 things are true:
 411          *   1) cap_effective has all caps
 412          *   2) we are root
 413          *   3) root is supposed to have all caps (SECURE_NOROOT)
 414          * Since this is just a normal root execing a process.
 415          *
 416          * Number 1 above might fail if you don't have a full bset, but I think
 417          * that is interesting information to audit.
 418          */
 419         if (!cap_isclear(current->cap_effective)) {
 420                 if (!cap_issubset(CAP_FULL_SET, current->cap_effective) ||
 421                     (bprm->e_uid != 0) || (current->uid != 0) ||
 422                     issecure(SECURE_NOROOT))
 423                         audit_log_bprm_fcaps(bprm, &pP, &pE);
 424         }
 425
 426         current->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
 427 }
 428
 429 int cap_bprm_secureexec (struct linux_binprm *bprm)
 430 {
 431         if (current_uid() != 0) {
 432                 if (bprm->cap_effective)
 433                         return 1;
 434                 if (!cap_isclear(bprm->cap_post_exec_permitted))
 435                         return 1;
 436         }
 437
 438         return (current_euid() != current_uid() ||
 439                 current_egid() != current_gid());
 440 }
 441
 442 int cap_inode_setxattr(struct dentry *dentry, const char *name,
 443                        const void *value, size_t size, int flags)
 444 {
 445         if (!strcmp(name, XATTR_NAME_CAPS)) {
 446                 if (!capable(CAP_SETFCAP))
 447                         return -EPERM;
 448                 return 0;
 449         } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
 450                      sizeof(XATTR_SECURITY_PREFIX) - 1)  &&
 451             !capable(CAP_SYS_ADMIN))
 452                 return -EPERM;
 453         return 0;
 454 }
 455
 456 int cap_inode_removexattr(struct dentry *dentry, const char *name)
 457 {
 458         if (!strcmp(name, XATTR_NAME_CAPS)) {
 459                 if (!capable(CAP_SETFCAP))
 460                         return -EPERM;
 461                 return 0;
 462         } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
 463                      sizeof(XATTR_SECURITY_PREFIX) - 1)  &&
 464             !capable(CAP_SYS_ADMIN))
 465                 return -EPERM;
 466         return 0;
 467 }
 468
 469 /* moved from kernel/sys.c. */
 470 /*
 471  * cap_emulate_setxuid() fixes the effective / permitted capabilities of
 472  * a process after a call to setuid, setreuid, or setresuid.
 473  *
 474  *  1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
 475  *  {r,e,s}uid != 0, the permitted and effective capabilities are
 476  *  cleared.
 477  *
 478  *  2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
 479  *  capabilities of the process are cleared.
 480  *
 481  *  3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
 482  *  capabilities are set to the permitted capabilities.
 483  *
 484  *  fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
 485  *  never happen.
 486  *
 487  *  -astor
 488  *
 489  * cevans - New behaviour, Oct '99
 490  * A process may, via prctl(), elect to keep its capabilities when it
 491  * calls setuid() and switches away from uid==0. Both permitted and
 492  * effective sets will be retained.
 493  * Without this change, it was impossible for a daemon to drop only some
 494  * of its privilege. The call to setuid(!=0) would drop all privileges!
 495  * Keeping uid 0 is not an option because uid 0 owns too many vital
 496  * files..
 497  * Thanks to Olaf Kirch and Peter Benie for spotting this.
 498  */
 499 static inline void cap_emulate_setxuid (int old_ruid, int old_euid,
 500                                         int old_suid)
 501 {
 502         uid_t euid = current_euid();
 503
 504         if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
 505             (current_uid()  != 0 && euid != 0 && current_suid() != 0) &&
 506             !issecure(SECURE_KEEP_CAPS)) {
 507                 cap_clear (current->cap_permitted);
 508                 cap_clear (current->cap_effective);
 509         }
 510         if (old_euid == 0 && euid != 0) {
 511                 cap_clear (current->cap_effective);
 512         }
 513         if (old_euid != 0 && euid == 0) {
 514                 current->cap_effective = current->cap_permitted;
 515         }
 516 }
 517
 518 int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
 519                           int flags)
 520 {
 521         switch (flags) {
 522         case LSM_SETID_RE:
 523         case LSM_SETID_ID:
 524         case LSM_SETID_RES:
 525                 /* Copied from kernel/sys.c:setreuid/setuid/setresuid. */
 526                 if (!issecure (SECURE_NO_SETUID_FIXUP)) {
 527                         cap_emulate_setxuid (old_ruid, old_euid, old_suid);
 528                 }
 529                 break;
 530         case LSM_SETID_FS:
 531                 {
 532                         uid_t old_fsuid = old_ruid;
 533
 534                         /* Copied from kernel/sys.c:setfsuid. */
 535
 536                         /*
 537                          * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
 538                          *          if not, we might be a bit too harsh here.
 539                          */
 540
 541                         if (!issecure (SECURE_NO_SETUID_FIXUP)) {
 542                                 if (old_fsuid == 0 && current_fsuid() != 0) {
 543                                         current->cap_effective =
 544                                                 cap_drop_fs_set(
 545                                                     current->cap_effective);
 546                                 }
 547                                 if (old_fsuid != 0 && current_fsuid() == 0) {
 548                                         current->cap_effective =
 549                                                 cap_raise_fs_set(
 550                                                     current->cap_effective,
 551                                                     current->cap_permitted);
 552                                 }
 553                         }
 554                         break;
 555                 }
 556         default:
 557                 return -EINVAL;
 558         }
 559
 560         return 0;
 561 }
 562
 563 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 564 /*
 565  * Rationale: code calling task_setscheduler, task_setioprio, and
 566  * task_setnice, assumes that
 567  *   . if capable(cap_sys_nice), then those actions should be allowed
 568  *   . if not capable(cap_sys_nice), but acting on your own processes,
 569  *      then those actions should be allowed
 570  * This is insufficient now since you can call code without suid, but
 571  * yet with increased caps.
 572  * So we check for increased caps on the target process.
 573  */
 574 static int cap_safe_nice(struct task_struct *p)
 575 {
 576         if (!cap_issubset(p->cap_permitted, current->cap_permitted) &&
 577             !capable(CAP_SYS_NICE))
 578                 return -EPERM;
 579         return 0;
 580 }
 581
 582 int cap_task_setscheduler (struct task_struct *p, int policy,
 583                            struct sched_param *lp)
 584 {
 585         return cap_safe_nice(p);
 586 }
 587
 588 int cap_task_setioprio (struct task_struct *p, int ioprio)
 589 {
 590         return cap_safe_nice(p);
 591 }
 592
 593 int cap_task_setnice (struct task_struct *p, int nice)
 594 {
 595         return cap_safe_nice(p);
 596 }
 597
 598 /*
 599  * called from kernel/sys.c for prctl(PR_CABSET_DROP)
 600  * done without task_capability_lock() because it introduces
 601  * no new races - i.e. only another task doing capget() on
 602  * this task could get inconsistent info.  There can be no
 603  * racing writer bc a task can only change its own caps.
 604  */
 605 static long cap_prctl_drop(unsigned long cap)
 606 {
 607         if (!capable(CAP_SETPCAP))
 608                 return -EPERM;
 609         if (!cap_valid(cap))
 610                 return -EINVAL;
 611         cap_lower(current->cap_bset, cap);
 612         return 0;
 613 }
 614
 615 #else
 616 int cap_task_setscheduler (struct task_struct *p, int policy,
 617                            struct sched_param *lp)
 618 {
 619         return 0;
 620 }
 621 int cap_task_setioprio (struct task_struct *p, int ioprio)
 622 {
 623         return 0;
 624 }
 625 int cap_task_setnice (struct task_struct *p, int nice)
 626 {
 627         return 0;
 628 }
 629 #endif
 630
 631 int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 632                    unsigned long arg4, unsigned long arg5, long *rc_p)
 633 {
 634         long error = 0;
 635
 636         switch (option) {
 637         case PR_CAPBSET_READ:
 638                 if (!cap_valid(arg2))
 639                         error = -EINVAL;
 640                 else
 641                         error = !!cap_raised(current->cap_bset, arg2);
 642                 break;
 643 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 644         case PR_CAPBSET_DROP:
 645                 error = cap_prctl_drop(arg2);
 646                 break;
 647
 648         /*
 649          * The next four prctl's remain to assist with transitioning a
 650          * system from legacy UID=0 based privilege (when filesystem
 651          * capabilities are not in use) to a system using filesystem
 652          * capabilities only - as the POSIX.1e draft intended.
 653          *
 654          * Note:
 655          *
 656          *  PR_SET_SECUREBITS =
 657          *      issecure_mask(SECURE_KEEP_CAPS_LOCKED)
 658          *    | issecure_mask(SECURE_NOROOT)
 659          *    | issecure_mask(SECURE_NOROOT_LOCKED)
 660          *    | issecure_mask(SECURE_NO_SETUID_FIXUP)
 661          *    | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
 662          *
 663          * will ensure that the current process and all of its
 664          * children will be locked into a pure
 665          * capability-based-privilege environment.
 666          */
 667         case PR_SET_SECUREBITS:
 668                 if ((((current->securebits & SECURE_ALL_LOCKS) >> 1)
 669                      & (current->securebits ^ arg2))                  /*[1]*/
 670                     || ((current->securebits & SECURE_ALL_LOCKS
 671                          & ~arg2))                                    /*[2]*/
 672                     || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
 673                     || (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0)) { /*[4]*/
 674                         /*
 675                          * [1] no changing of bits that are locked
 676                          * [2] no unlocking of locks
 677                          * [3] no setting of unsupported bits
 678                          * [4] doing anything requires privilege (go read about
 679                          *     the "sendmail capabilities bug")
 680                          */
 681                         error = -EPERM;  /* cannot change a locked bit */
 682                 } else {
 683                         current->securebits = arg2;
 684                 }
 685                 break;
 686         case PR_GET_SECUREBITS:
 687                 error = current->securebits;
 688                 break;
 689
 690 #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
 691
 692         case PR_GET_KEEPCAPS:
 693                 if (issecure(SECURE_KEEP_CAPS))
 694                         error = 1;
 695                 break;
 696         case PR_SET_KEEPCAPS:
 697                 if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
 698                         error = -EINVAL;
 699                 else if (issecure(SECURE_KEEP_CAPS_LOCKED))
 700                         error = -EPERM;
 701                 else if (arg2)
 702                         current->securebits |= issecure_mask(SECURE_KEEP_CAPS);
 703                 else
 704                         current->securebits &=
 705                                 ~issecure_mask(SECURE_KEEP_CAPS);
 706                 break;
 707
 708         default:
 709                 /* No functionality available - continue with default */
 710                 return 0;
 711         }
 712
 713         /* Functionality provided */
 714         *rc_p = error;
 715         return 1;
 716 }
 717
 718 void cap_task_reparent_to_init (struct task_struct *p)
 719 {
 720         cap_set_init_eff(p->cap_effective);
 721         cap_clear(p->cap_inheritable);
 722         cap_set_full(p->cap_permitted);
 723         p->securebits = SECUREBITS_DEFAULT;
 724         return;
 725 }
 726
 727 int cap_syslog (int type)
 728 {
 729         if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN))
 730                 return -EPERM;
 731         return 0;
 732 }
 733
 734 int cap_vm_enough_memory(struct mm_struct *mm, long pages)
 735 {
 736         int cap_sys_admin = 0;
 737
 738         if (cap_capable(current, CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT) == 0)
 739                 cap_sys_admin = 1;
 740         return __vm_enough_memory(mm, pages, cap_sys_admin);
 741 }
 742