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
  35 #define _LINUX_CAPABILITY_U32S_2     2
  36
  37 #define _LINUX_CAPABILITY_VERSION    _LINUX_CAPABILITY_VERSION_2
  38 #define _LINUX_CAPABILITY_U32S       _LINUX_CAPABILITY_U32S_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 #ifdef __KERNEL__
  81
  82 typedef struct kernel_cap_struct {
  83         __u32 cap[_LINUX_CAPABILITY_U32S];
  84 } kernel_cap_t;
  85
  86 #define _USER_CAP_HEADER_SIZE  (sizeof(struct __user_cap_header_struct))
  87 #define _KERNEL_CAP_T_SIZE     (sizeof(kernel_cap_t))
  88
  89 #endif
  90
  91
  92 /**
  93  ** POSIX-draft defined capabilities.
  94  **/
  95
  96 /* In a system with the [_POSIX_CHOWN_RESTRICTED] option defined, this
  97    overrides the restriction of changing file ownership and group
  98    ownership. */
  99
 100 #define CAP_CHOWN            0
 101
 102 /* Override all DAC access, including ACL execute access if
 103    [_POSIX_ACL] is defined. Excluding DAC access covered by
 104    CAP_LINUX_IMMUTABLE. */
 105
 106 #define CAP_DAC_OVERRIDE     1
 107
 108 /* Overrides all DAC restrictions regarding read and search on files
 109    and directories, including ACL restrictions if [_POSIX_ACL] is
 110    defined. Excluding DAC access covered by CAP_LINUX_IMMUTABLE. */
 111
 112 #define CAP_DAC_READ_SEARCH  2
 113
 114 /* Overrides all restrictions about allowed operations on files, where
 115    file owner ID must be equal to the user ID, except where CAP_FSETID
 116    is applicable. It doesn't override MAC and DAC restrictions. */
 117
 118 #define CAP_FOWNER           3
 119
 120 /* Overrides the following restrictions that the effective user ID
 121    shall match the file owner ID when setting the S_ISUID and S_ISGID
 122    bits on that file; that the effective group ID (or one of the
 123    supplementary group IDs) shall match the file owner ID when setting
 124    the S_ISGID bit on that file; that the S_ISUID and S_ISGID bits are
 125    cleared on successful return from chown(2) (not implemented). */
 126
 127 #define CAP_FSETID           4
 128
 129 /* Overrides the restriction that the real or effective user ID of a
 130    process sending a signal must match the real or effective user ID
 131    of the process receiving the signal. */
 132
 133 #define CAP_KILL             5
 134
 135 /* Allows setgid(2) manipulation */
 136 /* Allows setgroups(2) */
 137 /* Allows forged gids on socket credentials passing. */
 138
 139 #define CAP_SETGID           6
 140
 141 /* Allows set*uid(2) manipulation (including fsuid). */
 142 /* Allows forged pids on socket credentials passing. */
 143
 144 #define CAP_SETUID           7
 145
 146
 147 /**
 148  ** Linux-specific capabilities
 149  **/
 150
 151 /* Without VFS support for capabilities:
 152  *   Transfer any capability in your permitted set to any pid,
 153  *   remove any capability in your permitted set from any pid
 154  * With VFS support for capabilities (neither of above, but)
 155  *   Add any capability from current's capability bounding set
 156  *       to the current process' inheritable set
 157  *   Allow taking bits out of capability bounding set
 158  *   Allow modification of the securebits for a process
 159  */
 160
 161 #define CAP_SETPCAP          8
 162
 163 /* Allow modification of S_IMMUTABLE and S_APPEND file attributes */
 164
 165 #define CAP_LINUX_IMMUTABLE  9
 166
 167 /* Allows binding to TCP/UDP sockets below 1024 */
 168 /* Allows binding to ATM VCIs below 32 */
 169
 170 #define CAP_NET_BIND_SERVICE 10
 171
 172 /* Allow broadcasting, listen to multicast */
 173
 174 #define CAP_NET_BROADCAST    11
 175
 176 /* Allow interface configuration */
 177 /* Allow administration of IP firewall, masquerading and accounting */
 178 /* Allow setting debug option on sockets */
 179 /* Allow modification of routing tables */
 180 /* Allow setting arbitrary process / process group ownership on
 181    sockets */
 182 /* Allow binding to any address for transparent proxying */
 183 /* Allow setting TOS (type of service) */
 184 /* Allow setting promiscuous mode */
 185 /* Allow clearing driver statistics */
 186 /* Allow multicasting */
 187 /* Allow read/write of device-specific registers */
 188 /* Allow activation of ATM control sockets */
 189
 190 #define CAP_NET_ADMIN        12
 191
 192 /* Allow use of RAW sockets */
 193 /* Allow use of PACKET sockets */
 194
 195 #define CAP_NET_RAW          13
 196
 197 /* Allow locking of shared memory segments */
 198 /* Allow mlock and mlockall (which doesn't really have anything to do
 199    with IPC) */
 200
 201 #define CAP_IPC_LOCK         14
 202
 203 /* Override IPC ownership checks */
 204
 205 #define CAP_IPC_OWNER        15
 206
 207 /* Insert and remove kernel modules - modify kernel without limit */
 208 #define CAP_SYS_MODULE       16
 209
 210 /* Allow ioperm/iopl access */
 211 /* Allow sending USB messages to any device via /proc/bus/usb */
 212
 213 #define CAP_SYS_RAWIO        17
 214
 215 /* Allow use of chroot() */
 216
 217 #define CAP_SYS_CHROOT       18
 218
 219 /* Allow ptrace() of any process */
 220
 221 #define CAP_SYS_PTRACE       19
 222
 223 /* Allow configuration of process accounting */
 224
 225 #define CAP_SYS_PACCT        20
 226
 227 /* Allow configuration of the secure attention key */
 228 /* Allow administration of the random device */
 229 /* Allow examination and configuration of disk quotas */
 230 /* Allow configuring the kernel's syslog (printk behaviour) */
 231 /* Allow setting the domainname */
 232 /* Allow setting the hostname */
 233 /* Allow calling bdflush() */
 234 /* Allow mount() and umount(), setting up new smb connection */
 235 /* Allow some autofs root ioctls */
 236 /* Allow nfsservctl */
 237 /* Allow VM86_REQUEST_IRQ */
 238 /* Allow to read/write pci config on alpha */
 239 /* Allow irix_prctl on mips (setstacksize) */
 240 /* Allow flushing all cache on m68k (sys_cacheflush) */
 241 /* Allow removing semaphores */
 242 /* Used instead of CAP_CHOWN to "chown" IPC message queues, semaphores
 243    and shared memory */
 244 /* Allow locking/unlocking of shared memory segment */
 245 /* Allow turning swap on/off */
 246 /* Allow forged pids on socket credentials passing */
 247 /* Allow setting readahead and flushing buffers on block devices */
 248 /* Allow setting geometry in floppy driver */
 249 /* Allow turning DMA on/off in xd driver */
 250 /* Allow administration of md devices (mostly the above, but some
 251    extra ioctls) */
 252 /* Allow tuning the ide driver */
 253 /* Allow access to the nvram device */
 254 /* Allow administration of apm_bios, serial and bttv (TV) device */
 255 /* Allow manufacturer commands in isdn CAPI support driver */
 256 /* Allow reading non-standardized portions of pci configuration space */
 257 /* Allow DDI debug ioctl on sbpcd driver */
 258 /* Allow setting up serial ports */
 259 /* Allow sending raw qic-117 commands */
 260 /* Allow enabling/disabling tagged queuing on SCSI controllers and sending
 261    arbitrary SCSI commands */
 262 /* Allow setting encryption key on loopback filesystem */
 263 /* Allow setting zone reclaim policy */
 264
 265 #define CAP_SYS_ADMIN        21
 266
 267 /* Allow use of reboot() */
 268
 269 #define CAP_SYS_BOOT         22
 270
 271 /* Allow raising priority and setting priority on other (different
 272    UID) processes */
 273 /* Allow use of FIFO and round-robin (realtime) scheduling on own
 274    processes and setting the scheduling algorithm used by another
 275    process. */
 276 /* Allow setting cpu affinity on other processes */
 277
 278 #define CAP_SYS_NICE         23
 279
 280 /* Override resource limits. Set resource limits. */
 281 /* Override quota limits. */
 282 /* Override reserved space on ext2 filesystem */
 283 /* Modify data journaling mode on ext3 filesystem (uses journaling
 284    resources) */
 285 /* NOTE: ext2 honors fsuid when checking for resource overrides, so
 286    you can override using fsuid too */
 287 /* Override size restrictions on IPC message queues */
 288 /* Allow more than 64hz interrupts from the real-time clock */
 289 /* Override max number of consoles on console allocation */
 290 /* Override max number of keymaps */
 291
 292 #define CAP_SYS_RESOURCE     24
 293
 294 /* Allow manipulation of system clock */
 295 /* Allow irix_stime on mips */
 296 /* Allow setting the real-time clock */
 297
 298 #define CAP_SYS_TIME         25
 299
 300 /* Allow configuration of tty devices */
 301 /* Allow vhangup() of tty */
 302
 303 #define CAP_SYS_TTY_CONFIG   26
 304
 305 /* Allow the privileged aspects of mknod() */
 306
 307 #define CAP_MKNOD            27
 308
 309 /* Allow taking of leases on files */
 310
 311 #define CAP_LEASE            28
 312
 313 #define CAP_AUDIT_WRITE      29
 314
 315 #define CAP_AUDIT_CONTROL    30
 316
 317 #define CAP_SETFCAP          31
 318
 319 /* Override MAC access.
 320    The base kernel enforces no MAC policy.
 321    An LSM may enforce a MAC policy, and if it does and it chooses
 322    to implement capability based overrides of that policy, this is
 323    the capability it should use to do so. */
 324
 325 #define CAP_MAC_OVERRIDE     32
 326
 327 /* Allow MAC configuration or state changes.
 328    The base kernel requires no MAC configuration.
 329    An LSM may enforce a MAC policy, and if it does and it chooses
 330    to implement capability based checks on modifications to that
 331    policy or the data required to maintain it, this is the
 332    capability it should use to do so. */
 333
 334 #define CAP_MAC_ADMIN        33
 335
 336 #define CAP_LAST_CAP         CAP_MAC_ADMIN
 337
 338 #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP)
 339
 340 /*
 341  * Bit location of each capability (used by user-space library and kernel)
 342  */
 343
 344 #define CAP_TO_INDEX(x)     ((x) >> 5)        /* 1 << 5 == bits in __u32 */
 345 #define CAP_TO_MASK(x)      (1 << ((x) & 31)) /* mask for indexed __u32 */
 346
 347 #ifdef __KERNEL__
 348
 349 /*
 350  * Internal kernel functions only
 351  */
 352
 353 #define CAP_FOR_EACH_U32(__capi)  \
 354         for (__capi = 0; __capi < _LINUX_CAPABILITY_U32S; ++__capi)
 355
 356 # define CAP_FS_MASK_B0     (CAP_TO_MASK(CAP_CHOWN)             \
 357                             | CAP_TO_MASK(CAP_DAC_OVERRIDE)     \
 358                             | CAP_TO_MASK(CAP_DAC_READ_SEARCH)  \
 359                             | CAP_TO_MASK(CAP_FOWNER)           \
 360                             | CAP_TO_MASK(CAP_FSETID))
 361
 362 # define CAP_FS_MASK_B1     (CAP_TO_MASK(CAP_MAC_OVERRIDE))
 363
 364 #if _LINUX_CAPABILITY_U32S != 2
 365 # error Fix up hand-coded capability macro initializers
 366 #else /* HAND-CODED capability initializers */
 367
 368 # define CAP_EMPTY_SET    ((kernel_cap_t){{ 0, 0 }})
 369 # define CAP_FULL_SET     ((kernel_cap_t){{ ~0, ~0 }})
 370 # define CAP_INIT_EFF_SET ((kernel_cap_t){{ ~CAP_TO_MASK(CAP_SETPCAP), ~0 }})
 371 # define CAP_FS_SET       ((kernel_cap_t){{ CAP_FS_MASK_B0, CAP_FS_MASK_B1 } })
 372 # define CAP_NFSD_SET     ((kernel_cap_t){{ CAP_FS_MASK_B0|CAP_TO_MASK(CAP_SYS_RESOURCE), \
 373                                         CAP_FS_MASK_B1 } })
 374
 375 #endif /* _LINUX_CAPABILITY_U32S != 2 */
 376
 377 #define CAP_INIT_INH_SET    CAP_EMPTY_SET
 378
 379 # define cap_clear(c)         do { (c) = __cap_empty_set; } while (0)
 380 # define cap_set_full(c)      do { (c) = __cap_full_set; } while (0)
 381 # define cap_set_init_eff(c)  do { (c) = __cap_init_eff_set; } while (0)
 382
 383 #define cap_raise(c, flag)  ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
 384 #define cap_lower(c, flag)  ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
 385 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
 386
 387 #define CAP_BOP_ALL(c, a, b, OP)                                    \
 388 do {                                                                \
 389         unsigned __capi;                                            \
 390         CAP_FOR_EACH_U32(__capi) {                                  \
 391                 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi];     \
 392         }                                                           \
 393 } while (0)
 394
 395 #define CAP_UOP_ALL(c, a, OP)                                       \
 396 do {                                                                \
 397         unsigned __capi;                                            \
 398         CAP_FOR_EACH_U32(__capi) {                                  \
 399                 c.cap[__capi] = OP a.cap[__capi];                   \
 400         }                                                           \
 401 } while (0)
 402
 403 static inline kernel_cap_t cap_combine(const kernel_cap_t a,
 404                                        const kernel_cap_t b)
 405 {
 406         kernel_cap_t dest;
 407         CAP_BOP_ALL(dest, a, b, |);
 408         return dest;
 409 }
 410
 411 static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
 412                                          const kernel_cap_t b)
 413 {
 414         kernel_cap_t dest;
 415         CAP_BOP_ALL(dest, a, b, &);
 416         return dest;
 417 }
 418
 419 static inline kernel_cap_t cap_drop(const kernel_cap_t a,
 420                                     const kernel_cap_t drop)
 421 {
 422         kernel_cap_t dest;
 423         CAP_BOP_ALL(dest, a, drop, &~);
 424         return dest;
 425 }
 426
 427 static inline kernel_cap_t cap_invert(const kernel_cap_t c)
 428 {
 429         kernel_cap_t dest;
 430         CAP_UOP_ALL(dest, c, ~);
 431         return dest;
 432 }
 433
 434 static inline int cap_isclear(const kernel_cap_t a)
 435 {
 436         unsigned __capi;
 437         CAP_FOR_EACH_U32(__capi) {
 438                 if (a.cap[__capi] != 0)
 439                         return 0;
 440         }
 441         return 1;
 442 }
 443
 444 static inline int cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
 445 {
 446         kernel_cap_t dest;
 447         dest = cap_drop(a, set);
 448         return cap_isclear(dest);
 449 }
 450
 451 /* Used to decide between falling back on the old suser() or fsuser(). */
 452
 453 static inline int cap_is_fs_cap(int cap)
 454 {
 455         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 456         return !!(CAP_TO_MASK(cap) & __cap_fs_set.cap[CAP_TO_INDEX(cap)]);
 457 }
 458
 459 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
 460 {
 461         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 462         return cap_drop(a, __cap_fs_set);
 463 }
 464
 465 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
 466                                             const kernel_cap_t permitted)
 467 {
 468         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 469         return cap_combine(a,
 470                            cap_intersect(permitted, __cap_fs_set));
 471 }
 472
 473 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
 474 {
 475         const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
 476         return cap_drop(a, __cap_fs_set);
 477 }
 478
 479 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
 480                                               const kernel_cap_t permitted)
 481 {
 482         const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
 483         return cap_combine(a,
 484                            cap_intersect(permitted, __cap_nfsd_set));
 485 }
 486
 487 extern const kernel_cap_t __cap_empty_set;
 488 extern const kernel_cap_t __cap_full_set;
 489 extern const kernel_cap_t __cap_init_eff_set;
 490
 491 int capable(int cap);
 492 int __capable(struct task_struct *t, int cap);
 493
 494 #endif /* __KERNEL__ */
 495
 496 #endif /* !_LINUX_CAPABILITY_H */