include/linux/capability.h

   1 /*
   2  * This is <linux/capability.h>
   3  *
   4  * Andrew G. Morgan <morgan@kernel.org>
   5  * Alexander Kjeldaas <astor@guardian.no>
   6  * with help from Aleph1, Roland Buresund and Andrew Main.
   7  *
   8  * See here for the libcap library ("POSIX draft" compliance):
   9  *
  10  * ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/
  11  */
  12
  13 #ifndef _LINUX_CAPABILITY_H
  14 #define _LINUX_CAPABILITY_H
  15
  16 #include <linux/types.h>
  17
  18 struct task_struct;
  19
  20 /* User-level do most of the mapping between kernel and user
  21    capabilities based on the version tag given by the kernel. The
  22    kernel might be somewhat backwards compatible, but don't bet on
  23    it. */
  24
  25 /* Note, cap_t, is defined by POSIX (draft) to be an "opaque" pointer to
  26    a set of three capability sets.  The transposition of 3*the
  27    following structure to such a composite is better handled in a user
  28    library since the draft standard requires the use of malloc/free
  29    etc.. */
  30
  31 #define _LINUX_CAPABILITY_VERSION_1  0x19980330
  32 #define _LINUX_CAPABILITY_U32S_1     1
  33
  34 #define _LINUX_CAPABILITY_VERSION_2  0x20071026  /* deprecated - use v3 */
  35 #define _LINUX_CAPABILITY_U32S_2     2
  36
  37 #define _LINUX_CAPABILITY_VERSION_3  0x20080522
  38 #define _LINUX_CAPABILITY_U32S_3     2
  39
  40 typedef struct __user_cap_header_struct {
  41         __u32 version;
  42         int pid;
  43 } __user *cap_user_header_t;
  44
  45 typedef struct __user_cap_data_struct {
  46         __u32 effective;
  47         __u32 permitted;
  48         __u32 inheritable;
  49 } __user *cap_user_data_t;
  50
  51
  52 #define XATTR_CAPS_SUFFIX "capability"
  53 #define XATTR_NAME_CAPS XATTR_SECURITY_PREFIX XATTR_CAPS_SUFFIX
  54
  55 #define VFS_CAP_REVISION_MASK   0xFF000000
  56 #define VFS_CAP_REVISION_SHIFT  24
  57 #define VFS_CAP_FLAGS_MASK      ~VFS_CAP_REVISION_MASK
  58 #define VFS_CAP_FLAGS_EFFECTIVE 0x000001
  59
  60 #define VFS_CAP_REVISION_1      0x01000000
  61 #define VFS_CAP_U32_1           1
  62 #define XATTR_CAPS_SZ_1         (sizeof(__le32)*(1 + 2*VFS_CAP_U32_1))
  63
  64 #define VFS_CAP_REVISION_2      0x02000000
  65 #define VFS_CAP_U32_2           2
  66 #define XATTR_CAPS_SZ_2         (sizeof(__le32)*(1 + 2*VFS_CAP_U32_2))
  67
  68 #define XATTR_CAPS_SZ           XATTR_CAPS_SZ_2
  69 #define VFS_CAP_U32             VFS_CAP_U32_2
  70 #define VFS_CAP_REVISION        VFS_CAP_REVISION_2
  71
  72 struct vfs_cap_data {
  73         __le32 magic_etc;            /* Little endian */
  74         struct {
  75                 __le32 permitted;    /* Little endian */
  76                 __le32 inheritable;  /* Little endian */
  77         } data[VFS_CAP_U32];
  78 };
  79
  80 #ifndef __KERNEL__
  81
  82 /*
  83  * Backwardly compatible definition for source code - trapped in a
  84  * 32-bit world. If you find you need this, please consider using
  85  * libcap to untrap yourself...
  86  */
  87 #define _LINUX_CAPABILITY_VERSION  _LINUX_CAPABILITY_VERSION_1
  88 #define _LINUX_CAPABILITY_U32S     _LINUX_CAPABILITY_U32S_1
  89
  90 #else
  91
  92 #define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3
  93 #define _KERNEL_CAPABILITY_U32S    _LINUX_CAPABILITY_U32S_3
  94
  95 extern int file_caps_enabled;
  96
  97 typedef struct kernel_cap_struct {
  98         __u32 cap[_KERNEL_CAPABILITY_U32S];
  99 } kernel_cap_t;
 100
 101 /* exact same as vfs_cap_data but in cpu endian and always filled completely */
 102 struct cpu_vfs_cap_data {
 103         __u32 magic_etc;
 104         kernel_cap_t permitted;
 105         kernel_cap_t inheritable;
 106 };
 107
 108 #define _USER_CAP_HEADER_SIZE  (sizeof(struct __user_cap_header_struct))
 109 #define _KERNEL_CAP_T_SIZE     (sizeof(kernel_cap_t))
 110
 111 #endif
 112
 113
 114 /**
 115  ** POSIX-draft defined capabilities.
 116  **/
 117
 118 /* In a system with the [_POSIX_CHOWN_RESTRICTED] option defined, this
 119    overrides the restriction of changing file ownership and group
 120    ownership. */
 121
 122 #define CAP_CHOWN            0
 123
 124 /* Override all DAC access, including ACL execute access if
 125    [_POSIX_ACL] is defined. Excluding DAC access covered by
 126    CAP_LINUX_IMMUTABLE. */
 127
 128 #define CAP_DAC_OVERRIDE     1
 129
 130 /* Overrides all DAC restrictions regarding read and search on files
 131    and directories, including ACL restrictions if [_POSIX_ACL] is
 132    defined. Excluding DAC access covered by CAP_LINUX_IMMUTABLE. */
 133
 134 #define CAP_DAC_READ_SEARCH  2
 135
 136 /* Overrides all restrictions about allowed operations on files, where
 137    file owner ID must be equal to the user ID, except where CAP_FSETID
 138    is applicable. It doesn't override MAC and DAC restrictions. */
 139
 140 #define CAP_FOWNER           3
 141
 142 /* Overrides the following restrictions that the effective user ID
 143    shall match the file owner ID when setting the S_ISUID and S_ISGID
 144    bits on that file; that the effective group ID (or one of the
 145    supplementary group IDs) shall match the file owner ID when setting
 146    the S_ISGID bit on that file; that the S_ISUID and S_ISGID bits are
 147    cleared on successful return from chown(2) (not implemented). */
 148
 149 #define CAP_FSETID           4
 150
 151 /* Overrides the restriction that the real or effective user ID of a
 152    process sending a signal must match the real or effective user ID
 153    of the process receiving the signal. */
 154
 155 #define CAP_KILL             5
 156
 157 /* Allows setgid(2) manipulation */
 158 /* Allows setgroups(2) */
 159 /* Allows forged gids on socket credentials passing. */
 160
 161 #define CAP_SETGID           6
 162
 163 /* Allows set*uid(2) manipulation (including fsuid). */
 164 /* Allows forged pids on socket credentials passing. */
 165
 166 #define CAP_SETUID           7
 167
 168
 169 /**
 170  ** Linux-specific capabilities
 171  **/
 172
 173 /* Without VFS support for capabilities:
 174  *   Transfer any capability in your permitted set to any pid,
 175  *   remove any capability in your permitted set from any pid
 176  * With VFS support for capabilities (neither of above, but)
 177  *   Add any capability from current's capability bounding set
 178  *       to the current process' inheritable set
 179  *   Allow taking bits out of capability bounding set
 180  *   Allow modification of the securebits for a process
 181  */
 182
 183 #define CAP_SETPCAP          8
 184
 185 /* Allow modification of S_IMMUTABLE and S_APPEND file attributes */
 186
 187 #define CAP_LINUX_IMMUTABLE  9
 188
 189 /* Allows binding to TCP/UDP sockets below 1024 */
 190 /* Allows binding to ATM VCIs below 32 */
 191
 192 #define CAP_NET_BIND_SERVICE 10
 193
 194 /* Allow broadcasting, listen to multicast */
 195
 196 #define CAP_NET_BROADCAST    11
 197
 198 /* Allow interface configuration */
 199 /* Allow administration of IP firewall, masquerading and accounting */
 200 /* Allow setting debug option on sockets */
 201 /* Allow modification of routing tables */
 202 /* Allow setting arbitrary process / process group ownership on
 203    sockets */
 204 /* Allow binding to any address for transparent proxying */
 205 /* Allow setting TOS (type of service) */
 206 /* Allow setting promiscuous mode */
 207 /* Allow clearing driver statistics */
 208 /* Allow multicasting */
 209 /* Allow read/write of device-specific registers */
 210 /* Allow activation of ATM control sockets */
 211
 212 #define CAP_NET_ADMIN        12
 213
 214 /* Allow use of RAW sockets */
 215 /* Allow use of PACKET sockets */
 216
 217 #define CAP_NET_RAW          13
 218
 219 /* Allow locking of shared memory segments */
 220 /* Allow mlock and mlockall (which doesn't really have anything to do
 221    with IPC) */
 222
 223 #define CAP_IPC_LOCK         14
 224
 225 /* Override IPC ownership checks */
 226
 227 #define CAP_IPC_OWNER        15
 228
 229 /* Insert and remove kernel modules - modify kernel without limit */
 230 #define CAP_SYS_MODULE       16
 231
 232 /* Allow ioperm/iopl access */
 233 /* Allow sending USB messages to any device via /proc/bus/usb */
 234
 235 #define CAP_SYS_RAWIO        17
 236
 237 /* Allow use of chroot() */
 238
 239 #define CAP_SYS_CHROOT       18
 240
 241 /* Allow ptrace() of any process */
 242
 243 #define CAP_SYS_PTRACE       19
 244
 245 /* Allow configuration of process accounting */
 246
 247 #define CAP_SYS_PACCT        20
 248
 249 /* Allow configuration of the secure attention key */
 250 /* Allow administration of the random device */
 251 /* Allow examination and configuration of disk quotas */
 252 /* Allow configuring the kernel's syslog (printk behaviour) */
 253 /* Allow setting the domainname */
 254 /* Allow setting the hostname */
 255 /* Allow calling bdflush() */
 256 /* Allow mount() and umount(), setting up new smb connection */
 257 /* Allow some autofs root ioctls */
 258 /* Allow nfsservctl */
 259 /* Allow VM86_REQUEST_IRQ */
 260 /* Allow to read/write pci config on alpha */
 261 /* Allow irix_prctl on mips (setstacksize) */
 262 /* Allow flushing all cache on m68k (sys_cacheflush) */
 263 /* Allow removing semaphores */
 264 /* Used instead of CAP_CHOWN to "chown" IPC message queues, semaphores
 265    and shared memory */
 266 /* Allow locking/unlocking of shared memory segment */
 267 /* Allow turning swap on/off */
 268 /* Allow forged pids on socket credentials passing */
 269 /* Allow setting readahead and flushing buffers on block devices */
 270 /* Allow setting geometry in floppy driver */
 271 /* Allow turning DMA on/off in xd driver */
 272 /* Allow administration of md devices (mostly the above, but some
 273    extra ioctls) */
 274 /* Allow tuning the ide driver */
 275 /* Allow access to the nvram device */
 276 /* Allow administration of apm_bios, serial and bttv (TV) device */
 277 /* Allow manufacturer commands in isdn CAPI support driver */
 278 /* Allow reading non-standardized portions of pci configuration space */
 279 /* Allow DDI debug ioctl on sbpcd driver */
 280 /* Allow setting up serial ports */
 281 /* Allow sending raw qic-117 commands */
 282 /* Allow enabling/disabling tagged queuing on SCSI controllers and sending
 283    arbitrary SCSI commands */
 284 /* Allow setting encryption key on loopback filesystem */
 285 /* Allow setting zone reclaim policy */
 286
 287 #define CAP_SYS_ADMIN        21
 288
 289 /* Allow use of reboot() */
 290
 291 #define CAP_SYS_BOOT         22
 292
 293 /* Allow raising priority and setting priority on other (different
 294    UID) processes */
 295 /* Allow use of FIFO and round-robin (realtime) scheduling on own
 296    processes and setting the scheduling algorithm used by another
 297    process. */
 298 /* Allow setting cpu affinity on other processes */
 299
 300 #define CAP_SYS_NICE         23
 301
 302 /* Override resource limits. Set resource limits. */
 303 /* Override quota limits. */
 304 /* Override reserved space on ext2 filesystem */
 305 /* Modify data journaling mode on ext3 filesystem (uses journaling
 306    resources) */
 307 /* NOTE: ext2 honors fsuid when checking for resource overrides, so
 308    you can override using fsuid too */
 309 /* Override size restrictions on IPC message queues */
 310 /* Allow more than 64hz interrupts from the real-time clock */
 311 /* Override max number of consoles on console allocation */
 312 /* Override max number of keymaps */
 313
 314 #define CAP_SYS_RESOURCE     24
 315
 316 /* Allow manipulation of system clock */
 317 /* Allow irix_stime on mips */
 318 /* Allow setting the real-time clock */
 319
 320 #define CAP_SYS_TIME         25
 321
 322 /* Allow configuration of tty devices */
 323 /* Allow vhangup() of tty */
 324
 325 #define CAP_SYS_TTY_CONFIG   26
 326
 327 /* Allow the privileged aspects of mknod() */
 328
 329 #define CAP_MKNOD            27
 330
 331 /* Allow taking of leases on files */
 332
 333 #define CAP_LEASE            28
 334
 335 #define CAP_AUDIT_WRITE      29
 336
 337 #define CAP_AUDIT_CONTROL    30
 338
 339 #define CAP_SETFCAP          31
 340
 341 /* Override MAC access.
 342    The base kernel enforces no MAC policy.
 343    An LSM may enforce a MAC policy, and if it does and it chooses
 344    to implement capability based overrides of that policy, this is
 345    the capability it should use to do so. */
 346
 347 #define CAP_MAC_OVERRIDE     32
 348
 349 /* Allow MAC configuration or state changes.
 350    The base kernel requires no MAC configuration.
 351    An LSM may enforce a MAC policy, and if it does and it chooses
 352    to implement capability based checks on modifications to that
 353    policy or the data required to maintain it, this is the
 354    capability it should use to do so. */
 355
 356 #define CAP_MAC_ADMIN        33
 357
 358 #define CAP_LAST_CAP         CAP_MAC_ADMIN
 359
 360 #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP)
 361
 362 /*
 363  * Bit location of each capability (used by user-space library and kernel)
 364  */
 365
 366 #define CAP_TO_INDEX(x)     ((x) >> 5)        /* 1 << 5 == bits in __u32 */
 367 #define CAP_TO_MASK(x)      (1 << ((x) & 31)) /* mask for indexed __u32 */
 368
 369 #ifdef __KERNEL__
 370
 371 /*
 372  * Internal kernel functions only
 373  */
 374
 375 #define CAP_FOR_EACH_U32(__capi)  \
 376         for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
 377
 378 /*
 379  * CAP_FS_MASK and CAP_NFSD_MASKS:
 380  *
 381  * The fs mask is all the privileges that fsuid==0 historically meant.
 382  * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
 383  *
 384  * It has never meant setting security.* and trusted.* xattrs.
 385  *
 386  * We could also define fsmask as follows:
 387  *   1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
 388  *   2. The security.* and trusted.* xattrs are fs-related MAC permissions
 389  */
 390
 391 # define CAP_FS_MASK_B0     (CAP_TO_MASK(CAP_CHOWN)             \
 392                             | CAP_TO_MASK(CAP_MKNOD)            \
 393                             | CAP_TO_MASK(CAP_DAC_OVERRIDE)     \
 394                             | CAP_TO_MASK(CAP_DAC_READ_SEARCH)  \
 395                             | CAP_TO_MASK(CAP_FOWNER)           \
 396                             | CAP_TO_MASK(CAP_FSETID))
 397
 398 # define CAP_FS_MASK_B1     (CAP_TO_MASK(CAP_MAC_OVERRIDE))
 399
 400 #if _KERNEL_CAPABILITY_U32S != 2
 401 # error Fix up hand-coded capability macro initializers
 402 #else /* HAND-CODED capability initializers */
 403
 404 # define CAP_EMPTY_SET    ((kernel_cap_t){{ 0, 0 }})
 405 # define CAP_FULL_SET     ((kernel_cap_t){{ ~0, ~0 }})
 406 # define CAP_INIT_EFF_SET ((kernel_cap_t){{ ~CAP_TO_MASK(CAP_SETPCAP), ~0 }})
 407 # define CAP_FS_SET       ((kernel_cap_t){{ CAP_FS_MASK_B0 \
 408                                     | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
 409                                     CAP_FS_MASK_B1 } })
 410 # define CAP_NFSD_SET     ((kernel_cap_t){{ CAP_FS_MASK_B0 \
 411                                     | CAP_TO_MASK(CAP_SYS_RESOURCE), \
 412                                     CAP_FS_MASK_B1 } })
 413
 414 #endif /* _KERNEL_CAPABILITY_U32S != 2 */
 415
 416 #define CAP_INIT_INH_SET    CAP_EMPTY_SET
 417
 418 # define cap_clear(c)         do { (c) = __cap_empty_set; } while (0)
 419 # define cap_set_full(c)      do { (c) = __cap_full_set; } while (0)
 420 # define cap_set_init_eff(c)  do { (c) = __cap_init_eff_set; } while (0)
 421
 422 #define cap_raise(c, flag)  ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
 423 #define cap_lower(c, flag)  ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
 424 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
 425
 426 #define CAP_BOP_ALL(c, a, b, OP)                                    \
 427 do {                                                                \
 428         unsigned __capi;                                            \
 429         CAP_FOR_EACH_U32(__capi) {                                  \
 430                 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi];     \
 431         }                                                           \
 432 } while (0)
 433
 434 #define CAP_UOP_ALL(c, a, OP)                                       \
 435 do {                                                                \
 436         unsigned __capi;                                            \
 437         CAP_FOR_EACH_U32(__capi) {                                  \
 438                 c.cap[__capi] = OP a.cap[__capi];                   \
 439         }                                                           \
 440 } while (0)
 441
 442 static inline kernel_cap_t cap_combine(const kernel_cap_t a,
 443                                        const kernel_cap_t b)
 444 {
 445         kernel_cap_t dest;
 446         CAP_BOP_ALL(dest, a, b, |);
 447         return dest;
 448 }
 449
 450 static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
 451                                          const kernel_cap_t b)
 452 {
 453         kernel_cap_t dest;
 454         CAP_BOP_ALL(dest, a, b, &);
 455         return dest;
 456 }
 457
 458 static inline kernel_cap_t cap_drop(const kernel_cap_t a,
 459                                     const kernel_cap_t drop)
 460 {
 461         kernel_cap_t dest;
 462         CAP_BOP_ALL(dest, a, drop, &~);
 463         return dest;
 464 }
 465
 466 static inline kernel_cap_t cap_invert(const kernel_cap_t c)
 467 {
 468         kernel_cap_t dest;
 469         CAP_UOP_ALL(dest, c, ~);
 470         return dest;
 471 }
 472
 473 static inline int cap_isclear(const kernel_cap_t a)
 474 {
 475         unsigned __capi;
 476         CAP_FOR_EACH_U32(__capi) {
 477                 if (a.cap[__capi] != 0)
 478                         return 0;
 479         }
 480         return 1;
 481 }
 482
 483 /*
 484  * Check if "a" is a subset of "set".
 485  * return 1 if ALL of the capabilities in "a" are also in "set"
 486  *      cap_issubset(0101, 1111) will return 1
 487  * return 0 if ANY of the capabilities in "a" are not in "set"
 488  *      cap_issubset(1111, 0101) will return 0
 489  */
 490 static inline int cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
 491 {
 492         kernel_cap_t dest;
 493         dest = cap_drop(a, set);
 494         return cap_isclear(dest);
 495 }
 496
 497 /* Used to decide between falling back on the old suser() or fsuser(). */
 498
 499 static inline int cap_is_fs_cap(int cap)
 500 {
 501         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 502         return !!(CAP_TO_MASK(cap) & __cap_fs_set.cap[CAP_TO_INDEX(cap)]);
 503 }
 504
 505 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
 506 {
 507         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 508         return cap_drop(a, __cap_fs_set);
 509 }
 510
 511 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
 512                                             const kernel_cap_t permitted)
 513 {
 514         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 515         return cap_combine(a,
 516                            cap_intersect(permitted, __cap_fs_set));
 517 }
 518
 519 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
 520 {
 521         const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
 522         return cap_drop(a, __cap_fs_set);
 523 }
 524
 525 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
 526                                               const kernel_cap_t permitted)
 527 {
 528         const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
 529         return cap_combine(a,
 530                            cap_intersect(permitted, __cap_nfsd_set));
 531 }
 532
 533 extern const kernel_cap_t __cap_empty_set;
 534 extern const kernel_cap_t __cap_full_set;
 535 extern const kernel_cap_t __cap_init_eff_set;
 536
 537 /**
 538  * has_capability - Determine if a task has a superior capability available
 539  * @t: The task in question
 540  * @cap: The capability to be tested for
 541  *
 542  * Return true if the specified task has the given superior capability
 543  * currently in effect, false if not.
 544  *
 545  * Note that this does not set PF_SUPERPRIV on the task.
 546  */
 547 #define has_capability(t, cap) (security_real_capable((t), (cap)) == 0)
 548
 549 /**
 550  * has_capability_noaudit - Determine if a task has a superior capability available (unaudited)
 551  * @t: The task in question
 552  * @cap: The capability to be tested for
 553  *
 554  * Return true if the specified task has the given superior capability
 555  * currently in effect, false if not, but don't write an audit message for the
 556  * check.
 557  *
 558  * Note that this does not set PF_SUPERPRIV on the task.
 559  */
 560 #define has_capability_noaudit(t, cap) \
 561         (security_real_capable_noaudit((t), (cap)) == 0)
 562
 563 extern int capable(int cap);
 564
 565 /* audit system wants to get cap info from files as well */
 566 struct dentry;
 567 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
 568
 569 #endif /* __KERNEL__ */
 570
 571 #endif /* !_LINUX_CAPABILITY_H */