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