SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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/module.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/security.h>
  15 #include <linux/file.h>
  16 #include <linux/mm.h>
  17 #include <linux/mman.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/swap.h>
  20 #include <linux/skbuff.h>
  21 #include <linux/netlink.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/xattr.h>
  24 #include <linux/hugetlb.h>
  25 #include <linux/mount.h>
  26 #include <linux/sched.h>
  27 #include <linux/prctl.h>
  28 #include <linux/securebits.h>
  29
  30 int cap_netlink_send(struct sock *sk, struct sk_buff *skb)
  31 {
  32         NETLINK_CB(skb).eff_cap = current->cap_effective;
  33         return 0;
  34 }
  35
  36 int cap_netlink_recv(struct sk_buff *skb, int cap)
  37 {
  38         if (!cap_raised(NETLINK_CB(skb).eff_cap, cap))
  39                 return -EPERM;
  40         return 0;
  41 }
  42
  43 EXPORT_SYMBOL(cap_netlink_recv);
  44
  45 /*
  46  * NOTE WELL: cap_capable() cannot be used like the kernel's capable()
  47  * function.  That is, it has the reverse semantics: cap_capable()
  48  * returns 0 when a task has a capability, but the kernel's capable()
  49  * returns 1 for this case.
  50  */
  51 int cap_capable (struct task_struct *tsk, int cap)
  52 {
  53         /* Derived from include/linux/sched.h:capable. */
  54         if (cap_raised(tsk->cap_effective, cap))
  55                 return 0;
  56         return -EPERM;
  57 }
  58
  59 int cap_settime(struct timespec *ts, struct timezone *tz)
  60 {
  61         if (!capable(CAP_SYS_TIME))
  62                 return -EPERM;
  63         return 0;
  64 }
  65
  66 int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
  67 {
  68         /* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
  69         if (cap_issubset(child->cap_permitted, current->cap_permitted))
  70                 return 0;
  71         if (capable(CAP_SYS_PTRACE))
  72                 return 0;
  73         return -EPERM;
  74 }
  75
  76 int cap_ptrace_traceme(struct task_struct *parent)
  77 {
  78         /* Derived from arch/i386/kernel/ptrace.c:sys_ptrace. */
  79         if (cap_issubset(current->cap_permitted, parent->cap_permitted))
  80                 return 0;
  81         if (has_capability(parent, CAP_SYS_PTRACE))
  82                 return 0;
  83         return -EPERM;
  84 }
  85
  86 int cap_capget (struct task_struct *target, kernel_cap_t *effective,
  87                 kernel_cap_t *inheritable, kernel_cap_t *permitted)
  88 {
  89         /* Derived from kernel/capability.c:sys_capget. */
  90         *effective = target->cap_effective;
  91         *inheritable = target->cap_inheritable;
  92         *permitted = target->cap_permitted;
  93         return 0;
  94 }
  95
  96 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
  97
  98 static inline int cap_block_setpcap(struct task_struct *target)
  99 {
 100         /*
 101          * No support for remote process capability manipulation with
 102          * filesystem capability support.
 103          */
 104         return (target != current);
 105 }
 106
 107 static inline int cap_inh_is_capped(void)
 108 {
 109         /*
 110          * Return 1 if changes to the inheritable set are limited
 111          * to the old permitted set. That is, if the current task
 112          * does *not* possess the CAP_SETPCAP capability.
 113          */
 114         return (cap_capable(current, CAP_SETPCAP) != 0);
 115 }
 116
 117 static inline int cap_limit_ptraced_target(void) { return 1; }
 118
 119 #else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
 120
 121 static inline int cap_block_setpcap(struct task_struct *t) { return 0; }
 122 static inline int cap_inh_is_capped(void) { return 1; }
 123 static inline int cap_limit_ptraced_target(void)
 124 {
 125         return !capable(CAP_SETPCAP);
 126 }
 127
 128 #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
 129
 130 int cap_capset_check (struct task_struct *target, kernel_cap_t *effective,
 131                       kernel_cap_t *inheritable, kernel_cap_t *permitted)
 132 {
 133         if (cap_block_setpcap(target)) {
 134                 return -EPERM;
 135         }
 136         if (cap_inh_is_capped()
 137             && !cap_issubset(*inheritable,
 138                              cap_combine(target->cap_inheritable,
 139                                          current->cap_permitted))) {
 140                 /* incapable of using this inheritable set */
 141                 return -EPERM;
 142         }
 143         if (!cap_issubset(*inheritable,
 144                            cap_combine(target->cap_inheritable,
 145                                        current->cap_bset))) {
 146                 /* no new pI capabilities outside bounding set */
 147                 return -EPERM;
 148         }
 149
 150         /* verify restrictions on target's new Permitted set */
 151         if (!cap_issubset (*permitted,
 152                            cap_combine (target->cap_permitted,
 153                                         current->cap_permitted))) {
 154                 return -EPERM;
 155         }
 156
 157         /* verify the _new_Effective_ is a subset of the _new_Permitted_ */
 158         if (!cap_issubset (*effective, *permitted)) {
 159                 return -EPERM;
 160         }
 161
 162         return 0;
 163 }
 164
 165 void cap_capset_set (struct task_struct *target, kernel_cap_t *effective,
 166                      kernel_cap_t *inheritable, kernel_cap_t *permitted)
 167 {
 168         target->cap_effective = *effective;
 169         target->cap_inheritable = *inheritable;
 170         target->cap_permitted = *permitted;
 171 }
 172
 173 static inline void bprm_clear_caps(struct linux_binprm *bprm)
 174 {
 175         cap_clear(bprm->cap_post_exec_permitted);
 176         bprm->cap_effective = false;
 177 }
 178
 179 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 180
 181 int cap_inode_need_killpriv(struct dentry *dentry)
 182 {
 183         struct inode *inode = dentry->d_inode;
 184         int error;
 185
 186         if (!inode->i_op || !inode->i_op->getxattr)
 187                return 0;
 188
 189         error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0);
 190         if (error <= 0)
 191                 return 0;
 192         return 1;
 193 }
 194
 195 int cap_inode_killpriv(struct dentry *dentry)
 196 {
 197         struct inode *inode = dentry->d_inode;
 198
 199         if (!inode->i_op || !inode->i_op->removexattr)
 200                return 0;
 201
 202         return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
 203 }
 204
 205 static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
 206                                           struct linux_binprm *bprm)
 207 {
 208         unsigned i;
 209         int ret = 0;
 210
 211         if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
 212                 bprm->cap_effective = true;
 213         else
 214                 bprm->cap_effective = false;
 215
 216         CAP_FOR_EACH_U32(i) {
 217                 __u32 permitted = caps->permitted.cap[i];
 218                 __u32 inheritable = caps->inheritable.cap[i];
 219
 220                 /*
 221                  * pP' = (X & fP) | (pI & fI)
 222                  */
 223                 bprm->cap_post_exec_permitted.cap[i] =
 224                         (current->cap_bset.cap[i] & permitted) |
 225                         (current->cap_inheritable.cap[i] & inheritable);
 226
 227                 if (permitted & ~bprm->cap_post_exec_permitted.cap[i]) {
 228                         /*
 229                          * insufficient to execute correctly
 230                          */
 231                         ret = -EPERM;
 232                 }
 233         }
 234
 235         /*
 236          * For legacy apps, with no internal support for recognizing they
 237          * do not have enough capabilities, we return an error if they are
 238          * missing some "forced" (aka file-permitted) capabilities.
 239          */
 240         return bprm->cap_effective ? ret : 0;
 241 }
 242
 243 int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
 244 {
 245         struct inode *inode = dentry->d_inode;
 246         __u32 magic_etc;
 247         unsigned tocopy, i;
 248         int size;
 249         struct vfs_cap_data caps;
 250
 251         memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
 252
 253         if (!inode || !inode->i_op || !inode->i_op->getxattr)
 254                 return -ENODATA;
 255
 256         size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps,
 257                                    XATTR_CAPS_SZ);
 258         if (size == -ENODATA || size == -EOPNOTSUPP) {
 259                 /* no data, that's ok */
 260                 return -ENODATA;
 261         }
 262         if (size < 0)
 263                 return size;
 264
 265         if (size < sizeof(magic_etc))
 266                 return -EINVAL;
 267
 268         cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc);
 269
 270         switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
 271         case VFS_CAP_REVISION_1:
 272                 if (size != XATTR_CAPS_SZ_1)
 273                         return -EINVAL;
 274                 tocopy = VFS_CAP_U32_1;
 275                 break;
 276         case VFS_CAP_REVISION_2:
 277                 if (size != XATTR_CAPS_SZ_2)
 278                         return -EINVAL;
 279                 tocopy = VFS_CAP_U32_2;
 280                 break;
 281         default:
 282                 return -EINVAL;
 283         }
 284
 285         CAP_FOR_EACH_U32(i) {
 286                 if (i >= tocopy)
 287                         break;
 288                 cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted);
 289                 cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable);
 290         }
 291         return 0;
 292 }
 293
 294 /* Locate any VFS capabilities: */
 295 static int get_file_caps(struct linux_binprm *bprm)
 296 {
 297         struct dentry *dentry;
 298         int rc = 0;
 299         struct cpu_vfs_cap_data vcaps;
 300
 301         bprm_clear_caps(bprm);
 302
 303         if (!file_caps_enabled)
 304                 return 0;
 305
 306         if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)
 307                 return 0;
 308
 309         dentry = dget(bprm->file->f_dentry);
 310
 311         rc = get_vfs_caps_from_disk(dentry, &vcaps);
 312         if (rc < 0) {
 313                 if (rc == -EINVAL)
 314                         printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n",
 315                                 __func__, rc, bprm->filename);
 316                 else if (rc == -ENODATA)
 317                         rc = 0;
 318                 goto out;
 319         }
 320
 321         rc = bprm_caps_from_vfs_caps(&vcaps, bprm);
 322
 323 out:
 324         dput(dentry);
 325         if (rc)
 326                 bprm_clear_caps(bprm);
 327
 328         return rc;
 329 }
 330
 331 #else
 332 int cap_inode_need_killpriv(struct dentry *dentry)
 333 {
 334         return 0;
 335 }
 336
 337 int cap_inode_killpriv(struct dentry *dentry)
 338 {
 339         return 0;
 340 }
 341
 342 static inline int get_file_caps(struct linux_binprm *bprm)
 343 {
 344         bprm_clear_caps(bprm);
 345         return 0;
 346 }
 347 #endif
 348
 349 int cap_bprm_set_security (struct linux_binprm *bprm)
 350 {
 351         int ret;
 352
 353         ret = get_file_caps(bprm);
 354
 355         if (!issecure(SECURE_NOROOT)) {
 356                 /*
 357                  * To support inheritance of root-permissions and suid-root
 358                  * executables under compatibility mode, we override the
 359                  * capability sets for the file.
 360                  *
 361                  * If only the real uid is 0, we do not set the effective
 362                  * bit.
 363                  */
 364                 if (bprm->e_uid == 0 || current->uid == 0) {
 365                         /* pP' = (cap_bset & ~0) | (pI & ~0) */
 366                         bprm->cap_post_exec_permitted = cap_combine(
 367                                 current->cap_bset, current->cap_inheritable
 368                                 );
 369                         bprm->cap_effective = (bprm->e_uid == 0);
 370                         ret = 0;
 371                 }
 372         }
 373
 374         return ret;
 375 }
 376
 377 void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
 378 {
 379         if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||
 380             !cap_issubset(bprm->cap_post_exec_permitted,
 381                           current->cap_permitted)) {
 382                 set_dumpable(current->mm, suid_dumpable);
 383                 current->pdeath_signal = 0;
 384
 385                 if (unsafe & ~LSM_UNSAFE_PTRACE_CAP) {
 386                         if (!capable(CAP_SETUID)) {
 387                                 bprm->e_uid = current->uid;
 388                                 bprm->e_gid = current->gid;
 389                         }
 390                         if (cap_limit_ptraced_target()) {
 391                                 bprm->cap_post_exec_permitted = cap_intersect(
 392                                         bprm->cap_post_exec_permitted,
 393                                         current->cap_permitted);
 394                         }
 395                 }
 396         }
 397
 398         current->suid = current->euid = current->fsuid = bprm->e_uid;
 399         current->sgid = current->egid = current->fsgid = bprm->e_gid;
 400
 401         /* For init, we want to retain the capabilities set
 402          * in the init_task struct. Thus we skip the usual
 403          * capability rules */
 404         if (!is_global_init(current)) {
 405                 current->cap_permitted = bprm->cap_post_exec_permitted;
 406                 if (bprm->cap_effective)
 407                         current->cap_effective = bprm->cap_post_exec_permitted;
 408                 else
 409                         cap_clear(current->cap_effective);
 410         }
 411
 412         /* AUD: Audit candidate if current->cap_effective is set */
 413
 414         current->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
 415 }
 416
 417 int cap_bprm_secureexec (struct linux_binprm *bprm)
 418 {
 419         if (current->uid != 0) {
 420                 if (bprm->cap_effective)
 421                         return 1;
 422                 if (!cap_isclear(bprm->cap_post_exec_permitted))
 423                         return 1;
 424         }
 425
 426         return (current->euid != current->uid ||
 427                 current->egid != current->gid);
 428 }
 429
 430 int cap_inode_setxattr(struct dentry *dentry, const char *name,
 431                        const void *value, size_t size, int flags)
 432 {
 433         if (!strcmp(name, XATTR_NAME_CAPS)) {
 434                 if (!capable(CAP_SETFCAP))
 435                         return -EPERM;
 436                 return 0;
 437         } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
 438                      sizeof(XATTR_SECURITY_PREFIX) - 1)  &&
 439             !capable(CAP_SYS_ADMIN))
 440                 return -EPERM;
 441         return 0;
 442 }
 443
 444 int cap_inode_removexattr(struct dentry *dentry, const char *name)
 445 {
 446         if (!strcmp(name, XATTR_NAME_CAPS)) {
 447                 if (!capable(CAP_SETFCAP))
 448                         return -EPERM;
 449                 return 0;
 450         } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
 451                      sizeof(XATTR_SECURITY_PREFIX) - 1)  &&
 452             !capable(CAP_SYS_ADMIN))
 453                 return -EPERM;
 454         return 0;
 455 }
 456
 457 /* moved from kernel/sys.c. */
 458 /*
 459  * cap_emulate_setxuid() fixes the effective / permitted capabilities of
 460  * a process after a call to setuid, setreuid, or setresuid.
 461  *
 462  *  1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of
 463  *  {r,e,s}uid != 0, the permitted and effective capabilities are
 464  *  cleared.
 465  *
 466  *  2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective
 467  *  capabilities of the process are cleared.
 468  *
 469  *  3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective
 470  *  capabilities are set to the permitted capabilities.
 471  *
 472  *  fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should
 473  *  never happen.
 474  *
 475  *  -astor
 476  *
 477  * cevans - New behaviour, Oct '99
 478  * A process may, via prctl(), elect to keep its capabilities when it
 479  * calls setuid() and switches away from uid==0. Both permitted and
 480  * effective sets will be retained.
 481  * Without this change, it was impossible for a daemon to drop only some
 482  * of its privilege. The call to setuid(!=0) would drop all privileges!
 483  * Keeping uid 0 is not an option because uid 0 owns too many vital
 484  * files..
 485  * Thanks to Olaf Kirch and Peter Benie for spotting this.
 486  */
 487 static inline void cap_emulate_setxuid (int old_ruid, int old_euid,
 488                                         int old_suid)
 489 {
 490         if ((old_ruid == 0 || old_euid == 0 || old_suid == 0) &&
 491             (current->uid != 0 && current->euid != 0 && current->suid != 0) &&
 492             !issecure(SECURE_KEEP_CAPS)) {
 493                 cap_clear (current->cap_permitted);
 494                 cap_clear (current->cap_effective);
 495         }
 496         if (old_euid == 0 && current->euid != 0) {
 497                 cap_clear (current->cap_effective);
 498         }
 499         if (old_euid != 0 && current->euid == 0) {
 500                 current->cap_effective = current->cap_permitted;
 501         }
 502 }
 503
 504 int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t old_suid,
 505                           int flags)
 506 {
 507         switch (flags) {
 508         case LSM_SETID_RE:
 509         case LSM_SETID_ID:
 510         case LSM_SETID_RES:
 511                 /* Copied from kernel/sys.c:setreuid/setuid/setresuid. */
 512                 if (!issecure (SECURE_NO_SETUID_FIXUP)) {
 513                         cap_emulate_setxuid (old_ruid, old_euid, old_suid);
 514                 }
 515                 break;
 516         case LSM_SETID_FS:
 517                 {
 518                         uid_t old_fsuid = old_ruid;
 519
 520                         /* Copied from kernel/sys.c:setfsuid. */
 521
 522                         /*
 523                          * FIXME - is fsuser used for all CAP_FS_MASK capabilities?
 524                          *          if not, we might be a bit too harsh here.
 525                          */
 526
 527                         if (!issecure (SECURE_NO_SETUID_FIXUP)) {
 528                                 if (old_fsuid == 0 && current->fsuid != 0) {
 529                                         current->cap_effective =
 530                                                 cap_drop_fs_set(
 531                                                     current->cap_effective);
 532                                 }
 533                                 if (old_fsuid != 0 && current->fsuid == 0) {
 534                                         current->cap_effective =
 535                                                 cap_raise_fs_set(
 536                                                     current->cap_effective,
 537                                                     current->cap_permitted);
 538                                 }
 539                         }
 540                         break;
 541                 }
 542         default:
 543                 return -EINVAL;
 544         }
 545
 546         return 0;
 547 }
 548
 549 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 550 /*
 551  * Rationale: code calling task_setscheduler, task_setioprio, and
 552  * task_setnice, assumes that
 553  *   . if capable(cap_sys_nice), then those actions should be allowed
 554  *   . if not capable(cap_sys_nice), but acting on your own processes,
 555  *      then those actions should be allowed
 556  * This is insufficient now since you can call code without suid, but
 557  * yet with increased caps.
 558  * So we check for increased caps on the target process.
 559  */
 560 static int cap_safe_nice(struct task_struct *p)
 561 {
 562         if (!cap_issubset(p->cap_permitted, current->cap_permitted) &&
 563             !capable(CAP_SYS_NICE))
 564                 return -EPERM;
 565         return 0;
 566 }
 567
 568 int cap_task_setscheduler (struct task_struct *p, int policy,
 569                            struct sched_param *lp)
 570 {
 571         return cap_safe_nice(p);
 572 }
 573
 574 int cap_task_setioprio (struct task_struct *p, int ioprio)
 575 {
 576         return cap_safe_nice(p);
 577 }
 578
 579 int cap_task_setnice (struct task_struct *p, int nice)
 580 {
 581         return cap_safe_nice(p);
 582 }
 583
 584 /*
 585  * called from kernel/sys.c for prctl(PR_CABSET_DROP)
 586  * done without task_capability_lock() because it introduces
 587  * no new races - i.e. only another task doing capget() on
 588  * this task could get inconsistent info.  There can be no
 589  * racing writer bc a task can only change its own caps.
 590  */
 591 static long cap_prctl_drop(unsigned long cap)
 592 {
 593         if (!capable(CAP_SETPCAP))
 594                 return -EPERM;
 595         if (!cap_valid(cap))
 596                 return -EINVAL;
 597         cap_lower(current->cap_bset, cap);
 598         return 0;
 599 }
 600
 601 #else
 602 int cap_task_setscheduler (struct task_struct *p, int policy,
 603                            struct sched_param *lp)
 604 {
 605         return 0;
 606 }
 607 int cap_task_setioprio (struct task_struct *p, int ioprio)
 608 {
 609         return 0;
 610 }
 611 int cap_task_setnice (struct task_struct *p, int nice)
 612 {
 613         return 0;
 614 }
 615 #endif
 616
 617 int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 618                    unsigned long arg4, unsigned long arg5, long *rc_p)
 619 {
 620         long error = 0;
 621
 622         switch (option) {
 623         case PR_CAPBSET_READ:
 624                 if (!cap_valid(arg2))
 625                         error = -EINVAL;
 626                 else
 627                         error = !!cap_raised(current->cap_bset, arg2);
 628                 break;
 629 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
 630         case PR_CAPBSET_DROP:
 631                 error = cap_prctl_drop(arg2);
 632                 break;
 633
 634         /*
 635          * The next four prctl's remain to assist with transitioning a
 636          * system from legacy UID=0 based privilege (when filesystem
 637          * capabilities are not in use) to a system using filesystem
 638          * capabilities only - as the POSIX.1e draft intended.
 639          *
 640          * Note:
 641          *
 642          *  PR_SET_SECUREBITS =
 643          *      issecure_mask(SECURE_KEEP_CAPS_LOCKED)
 644          *    | issecure_mask(SECURE_NOROOT)
 645          *    | issecure_mask(SECURE_NOROOT_LOCKED)
 646          *    | issecure_mask(SECURE_NO_SETUID_FIXUP)
 647          *    | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED)
 648          *
 649          * will ensure that the current process and all of its
 650          * children will be locked into a pure
 651          * capability-based-privilege environment.
 652          */
 653         case PR_SET_SECUREBITS:
 654                 if ((((current->securebits & SECURE_ALL_LOCKS) >> 1)
 655                      & (current->securebits ^ arg2))                  /*[1]*/
 656                     || ((current->securebits & SECURE_ALL_LOCKS
 657                          & ~arg2))                                    /*[2]*/
 658                     || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/
 659                     || (cap_capable(current, CAP_SETPCAP) != 0)) {    /*[4]*/
 660                         /*
 661                          * [1] no changing of bits that are locked
 662                          * [2] no unlocking of locks
 663                          * [3] no setting of unsupported bits
 664                          * [4] doing anything requires privilege (go read about
 665                          *     the "sendmail capabilities bug")
 666                          */
 667                         error = -EPERM;  /* cannot change a locked bit */
 668                 } else {
 669                         current->securebits = arg2;
 670                 }
 671                 break;
 672         case PR_GET_SECUREBITS:
 673                 error = current->securebits;
 674                 break;
 675
 676 #endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
 677
 678         case PR_GET_KEEPCAPS:
 679                 if (issecure(SECURE_KEEP_CAPS))
 680                         error = 1;
 681                 break;
 682         case PR_SET_KEEPCAPS:
 683                 if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */
 684                         error = -EINVAL;
 685                 else if (issecure(SECURE_KEEP_CAPS_LOCKED))
 686                         error = -EPERM;
 687                 else if (arg2)
 688                         current->securebits |= issecure_mask(SECURE_KEEP_CAPS);
 689                 else
 690                         current->securebits &=
 691                                 ~issecure_mask(SECURE_KEEP_CAPS);
 692                 break;
 693
 694         default:
 695                 /* No functionality available - continue with default */
 696                 return 0;
 697         }
 698
 699         /* Functionality provided */
 700         *rc_p = error;
 701         return 1;
 702 }
 703
 704 void cap_task_reparent_to_init (struct task_struct *p)
 705 {
 706         cap_set_init_eff(p->cap_effective);
 707         cap_clear(p->cap_inheritable);
 708         cap_set_full(p->cap_permitted);
 709         p->securebits = SECUREBITS_DEFAULT;
 710         return;
 711 }
 712
 713 int cap_syslog (int type)
 714 {
 715         if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN))
 716                 return -EPERM;
 717         return 0;
 718 }
 719
 720 int cap_vm_enough_memory(struct mm_struct *mm, long pages)
 721 {
 722         int cap_sys_admin = 0;
 723
 724         if (cap_capable(current, CAP_SYS_ADMIN) == 0)
 725                 cap_sys_admin = 1;
 726         return __vm_enough_memory(mm, pages, cap_sys_admin);
 727 }
 728