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 #ifdef CONFIG_SECURITY_FILE_CAPABILITIES
  96 extern int file_caps_enabled;
  97 #endif
  98
  99 typedef struct kernel_cap_struct {
 100         __u32 cap[_KERNEL_CAPABILITY_U32S];
 101 } kernel_cap_t;
 102
 103 /* exact same as vfs_cap_data but in cpu endian and always filled completely */
 104 struct cpu_vfs_cap_data {
 105         __u32 magic_etc;
 106         kernel_cap_t permitted;
 107         kernel_cap_t inheritable;
 108 };
 109
 110 #define _USER_CAP_HEADER_SIZE  (sizeof(struct __user_cap_header_struct))
 111 #define _KERNEL_CAP_T_SIZE     (sizeof(kernel_cap_t))
 112
 113 #endif
 114
 115
 116 /**
 117  ** POSIX-draft defined capabilities.
 118  **/
 119
 120 /* In a system with the [_POSIX_CHOWN_RESTRICTED] option defined, this
 121    overrides the restriction of changing file ownership and group
 122    ownership. */
 123
 124 #define CAP_CHOWN            0
 125
 126 /* Override all DAC access, including ACL execute access if
 127    [_POSIX_ACL] is defined. Excluding DAC access covered by
 128    CAP_LINUX_IMMUTABLE. */
 129
 130 #define CAP_DAC_OVERRIDE     1
 131
 132 /* Overrides all DAC restrictions regarding read and search on files
 133    and directories, including ACL restrictions if [_POSIX_ACL] is
 134    defined. Excluding DAC access covered by CAP_LINUX_IMMUTABLE. */
 135
 136 #define CAP_DAC_READ_SEARCH  2
 137
 138 /* Overrides all restrictions about allowed operations on files, where
 139    file owner ID must be equal to the user ID, except where CAP_FSETID
 140    is applicable. It doesn't override MAC and DAC restrictions. */
 141
 142 #define CAP_FOWNER           3
 143
 144 /* Overrides the following restrictions that the effective user ID
 145    shall match the file owner ID when setting the S_ISUID and S_ISGID
 146    bits on that file; that the effective group ID (or one of the
 147    supplementary group IDs) shall match the file owner ID when setting
 148    the S_ISGID bit on that file; that the S_ISUID and S_ISGID bits are
 149    cleared on successful return from chown(2) (not implemented). */
 150
 151 #define CAP_FSETID           4
 152
 153 /* Overrides the restriction that the real or effective user ID of a
 154    process sending a signal must match the real or effective user ID
 155    of the process receiving the signal. */
 156
 157 #define CAP_KILL             5
 158
 159 /* Allows setgid(2) manipulation */
 160 /* Allows setgroups(2) */
 161 /* Allows forged gids on socket credentials passing. */
 162
 163 #define CAP_SETGID           6
 164
 165 /* Allows set*uid(2) manipulation (including fsuid). */
 166 /* Allows forged pids on socket credentials passing. */
 167
 168 #define CAP_SETUID           7
 169
 170
 171 /**
 172  ** Linux-specific capabilities
 173  **/
 174
 175 /* Without VFS support for capabilities:
 176  *   Transfer any capability in your permitted set to any pid,
 177  *   remove any capability in your permitted set from any pid
 178  * With VFS support for capabilities (neither of above, but)
 179  *   Add any capability from current's capability bounding set
 180  *       to the current process' inheritable set
 181  *   Allow taking bits out of capability bounding set
 182  *   Allow modification of the securebits for a process
 183  */
 184
 185 #define CAP_SETPCAP          8
 186
 187 /* Allow modification of S_IMMUTABLE and S_APPEND file attributes */
 188
 189 #define CAP_LINUX_IMMUTABLE  9
 190
 191 /* Allows binding to TCP/UDP sockets below 1024 */
 192 /* Allows binding to ATM VCIs below 32 */
 193
 194 #define CAP_NET_BIND_SERVICE 10
 195
 196 /* Allow broadcasting, listen to multicast */
 197
 198 #define CAP_NET_BROADCAST    11
 199
 200 /* Allow interface configuration */
 201 /* Allow administration of IP firewall, masquerading and accounting */
 202 /* Allow setting debug option on sockets */
 203 /* Allow modification of routing tables */
 204 /* Allow setting arbitrary process / process group ownership on
 205    sockets */
 206 /* Allow binding to any address for transparent proxying */
 207 /* Allow setting TOS (type of service) */
 208 /* Allow setting promiscuous mode */
 209 /* Allow clearing driver statistics */
 210 /* Allow multicasting */
 211 /* Allow read/write of device-specific registers */
 212 /* Allow activation of ATM control sockets */
 213
 214 #define CAP_NET_ADMIN        12
 215
 216 /* Allow use of RAW sockets */
 217 /* Allow use of PACKET sockets */
 218
 219 #define CAP_NET_RAW          13
 220
 221 /* Allow locking of shared memory segments */
 222 /* Allow mlock and mlockall (which doesn't really have anything to do
 223    with IPC) */
 224
 225 #define CAP_IPC_LOCK         14
 226
 227 /* Override IPC ownership checks */
 228
 229 #define CAP_IPC_OWNER        15
 230
 231 /* Insert and remove kernel modules - modify kernel without limit */
 232 #define CAP_SYS_MODULE       16
 233
 234 /* Allow ioperm/iopl access */
 235 /* Allow sending USB messages to any device via /proc/bus/usb */
 236
 237 #define CAP_SYS_RAWIO        17
 238
 239 /* Allow use of chroot() */
 240
 241 #define CAP_SYS_CHROOT       18
 242
 243 /* Allow ptrace() of any process */
 244
 245 #define CAP_SYS_PTRACE       19
 246
 247 /* Allow configuration of process accounting */
 248
 249 #define CAP_SYS_PACCT        20
 250
 251 /* Allow configuration of the secure attention key */
 252 /* Allow administration of the random device */
 253 /* Allow examination and configuration of disk quotas */
 254 /* Allow configuring the kernel's syslog (printk behaviour) */
 255 /* Allow setting the domainname */
 256 /* Allow setting the hostname */
 257 /* Allow calling bdflush() */
 258 /* Allow mount() and umount(), setting up new smb connection */
 259 /* Allow some autofs root ioctls */
 260 /* Allow nfsservctl */
 261 /* Allow VM86_REQUEST_IRQ */
 262 /* Allow to read/write pci config on alpha */
 263 /* Allow irix_prctl on mips (setstacksize) */
 264 /* Allow flushing all cache on m68k (sys_cacheflush) */
 265 /* Allow removing semaphores */
 266 /* Used instead of CAP_CHOWN to "chown" IPC message queues, semaphores
 267    and shared memory */
 268 /* Allow locking/unlocking of shared memory segment */
 269 /* Allow turning swap on/off */
 270 /* Allow forged pids on socket credentials passing */
 271 /* Allow setting readahead and flushing buffers on block devices */
 272 /* Allow setting geometry in floppy driver */
 273 /* Allow turning DMA on/off in xd driver */
 274 /* Allow administration of md devices (mostly the above, but some
 275    extra ioctls) */
 276 /* Allow tuning the ide driver */
 277 /* Allow access to the nvram device */
 278 /* Allow administration of apm_bios, serial and bttv (TV) device */
 279 /* Allow manufacturer commands in isdn CAPI support driver */
 280 /* Allow reading non-standardized portions of pci configuration space */
 281 /* Allow DDI debug ioctl on sbpcd driver */
 282 /* Allow setting up serial ports */
 283 /* Allow sending raw qic-117 commands */
 284 /* Allow enabling/disabling tagged queuing on SCSI controllers and sending
 285    arbitrary SCSI commands */
 286 /* Allow setting encryption key on loopback filesystem */
 287 /* Allow setting zone reclaim policy */
 288
 289 #define CAP_SYS_ADMIN        21
 290
 291 /* Allow use of reboot() */
 292
 293 #define CAP_SYS_BOOT         22
 294
 295 /* Allow raising priority and setting priority on other (different
 296    UID) processes */
 297 /* Allow use of FIFO and round-robin (realtime) scheduling on own
 298    processes and setting the scheduling algorithm used by another
 299    process. */
 300 /* Allow setting cpu affinity on other processes */
 301
 302 #define CAP_SYS_NICE         23
 303
 304 /* Override resource limits. Set resource limits. */
 305 /* Override quota limits. */
 306 /* Override reserved space on ext2 filesystem */
 307 /* Modify data journaling mode on ext3 filesystem (uses journaling
 308    resources) */
 309 /* NOTE: ext2 honors fsuid when checking for resource overrides, so
 310    you can override using fsuid too */
 311 /* Override size restrictions on IPC message queues */
 312 /* Allow more than 64hz interrupts from the real-time clock */
 313 /* Override max number of consoles on console allocation */
 314 /* Override max number of keymaps */
 315
 316 #define CAP_SYS_RESOURCE     24
 317
 318 /* Allow manipulation of system clock */
 319 /* Allow irix_stime on mips */
 320 /* Allow setting the real-time clock */
 321
 322 #define CAP_SYS_TIME         25
 323
 324 /* Allow configuration of tty devices */
 325 /* Allow vhangup() of tty */
 326
 327 #define CAP_SYS_TTY_CONFIG   26
 328
 329 /* Allow the privileged aspects of mknod() */
 330
 331 #define CAP_MKNOD            27
 332
 333 /* Allow taking of leases on files */
 334
 335 #define CAP_LEASE            28
 336
 337 #define CAP_AUDIT_WRITE      29
 338
 339 #define CAP_AUDIT_CONTROL    30
 340
 341 #define CAP_SETFCAP          31
 342
 343 /* Override MAC access.
 344    The base kernel enforces no MAC policy.
 345    An LSM may enforce a MAC policy, and if it does and it chooses
 346    to implement capability based overrides of that policy, this is
 347    the capability it should use to do so. */
 348
 349 #define CAP_MAC_OVERRIDE     32
 350
 351 /* Allow MAC configuration or state changes.
 352    The base kernel requires no MAC configuration.
 353    An LSM may enforce a MAC policy, and if it does and it chooses
 354    to implement capability based checks on modifications to that
 355    policy or the data required to maintain it, this is the
 356    capability it should use to do so. */
 357
 358 #define CAP_MAC_ADMIN        33
 359
 360 #define CAP_LAST_CAP         CAP_MAC_ADMIN
 361
 362 #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP)
 363
 364 /*
 365  * Bit location of each capability (used by user-space library and kernel)
 366  */
 367
 368 #define CAP_TO_INDEX(x)     ((x) >> 5)        /* 1 << 5 == bits in __u32 */
 369 #define CAP_TO_MASK(x)      (1 << ((x) & 31)) /* mask for indexed __u32 */
 370
 371 #ifdef __KERNEL__
 372
 373 /*
 374  * Internal kernel functions only
 375  */
 376
 377 #define CAP_FOR_EACH_U32(__capi)  \
 378         for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
 379
 380 /*
 381  * CAP_FS_MASK and CAP_NFSD_MASKS:
 382  *
 383  * The fs mask is all the privileges that fsuid==0 historically meant.
 384  * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
 385  *
 386  * It has never meant setting security.* and trusted.* xattrs.
 387  *
 388  * We could also define fsmask as follows:
 389  *   1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
 390  *   2. The security.* and trusted.* xattrs are fs-related MAC permissions
 391  */
 392
 393 # define CAP_FS_MASK_B0     (CAP_TO_MASK(CAP_CHOWN)             \
 394                             | CAP_TO_MASK(CAP_MKNOD)            \
 395                             | CAP_TO_MASK(CAP_DAC_OVERRIDE)     \
 396                             | CAP_TO_MASK(CAP_DAC_READ_SEARCH)  \
 397                             | CAP_TO_MASK(CAP_FOWNER)           \
 398                             | CAP_TO_MASK(CAP_FSETID))
 399
 400 # define CAP_FS_MASK_B1     (CAP_TO_MASK(CAP_MAC_OVERRIDE))
 401
 402 #if _KERNEL_CAPABILITY_U32S != 2
 403 # error Fix up hand-coded capability macro initializers
 404 #else /* HAND-CODED capability initializers */
 405
 406 # define CAP_EMPTY_SET    ((kernel_cap_t){{ 0, 0 }})
 407 # define CAP_FULL_SET     ((kernel_cap_t){{ ~0, ~0 }})
 408 # define CAP_INIT_EFF_SET ((kernel_cap_t){{ ~CAP_TO_MASK(CAP_SETPCAP), ~0 }})
 409 # define CAP_FS_SET       ((kernel_cap_t){{ CAP_FS_MASK_B0 \
 410                                     | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
 411                                     CAP_FS_MASK_B1 } })
 412 # define CAP_NFSD_SET     ((kernel_cap_t){{ CAP_FS_MASK_B0 \
 413                                     | CAP_TO_MASK(CAP_SYS_RESOURCE), \
 414                                     CAP_FS_MASK_B1 } })
 415
 416 #endif /* _KERNEL_CAPABILITY_U32S != 2 */
 417
 418 #define CAP_INIT_INH_SET    CAP_EMPTY_SET
 419
 420 # define cap_clear(c)         do { (c) = __cap_empty_set; } while (0)
 421 # define cap_set_full(c)      do { (c) = __cap_full_set; } while (0)
 422 # define cap_set_init_eff(c)  do { (c) = __cap_init_eff_set; } while (0)
 423
 424 #define cap_raise(c, flag)  ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
 425 #define cap_lower(c, flag)  ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
 426 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
 427
 428 #define CAP_BOP_ALL(c, a, b, OP)                                    \
 429 do {                                                                \
 430         unsigned __capi;                                            \
 431         CAP_FOR_EACH_U32(__capi) {                                  \
 432                 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi];     \
 433         }                                                           \
 434 } while (0)
 435
 436 #define CAP_UOP_ALL(c, a, OP)                                       \
 437 do {                                                                \
 438         unsigned __capi;                                            \
 439         CAP_FOR_EACH_U32(__capi) {                                  \
 440                 c.cap[__capi] = OP a.cap[__capi];                   \
 441         }                                                           \
 442 } while (0)
 443
 444 static inline kernel_cap_t cap_combine(const kernel_cap_t a,
 445                                        const kernel_cap_t b)
 446 {
 447         kernel_cap_t dest;
 448         CAP_BOP_ALL(dest, a, b, |);
 449         return dest;
 450 }
 451
 452 static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
 453                                          const kernel_cap_t b)
 454 {
 455         kernel_cap_t dest;
 456         CAP_BOP_ALL(dest, a, b, &);
 457         return dest;
 458 }
 459
 460 static inline kernel_cap_t cap_drop(const kernel_cap_t a,
 461                                     const kernel_cap_t drop)
 462 {
 463         kernel_cap_t dest;
 464         CAP_BOP_ALL(dest, a, drop, &~);
 465         return dest;
 466 }
 467
 468 static inline kernel_cap_t cap_invert(const kernel_cap_t c)
 469 {
 470         kernel_cap_t dest;
 471         CAP_UOP_ALL(dest, c, ~);
 472         return dest;
 473 }
 474
 475 static inline int cap_isclear(const kernel_cap_t a)
 476 {
 477         unsigned __capi;
 478         CAP_FOR_EACH_U32(__capi) {
 479                 if (a.cap[__capi] != 0)
 480                         return 0;
 481         }
 482         return 1;
 483 }
 484
 485 /*
 486  * Check if "a" is a subset of "set".
 487  * return 1 if ALL of the capabilities in "a" are also in "set"
 488  *      cap_issubset(0101, 1111) will return 1
 489  * return 0 if ANY of the capabilities in "a" are not in "set"
 490  *      cap_issubset(1111, 0101) will return 0
 491  */
 492 static inline int cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
 493 {
 494         kernel_cap_t dest;
 495         dest = cap_drop(a, set);
 496         return cap_isclear(dest);
 497 }
 498
 499 /* Used to decide between falling back on the old suser() or fsuser(). */
 500
 501 static inline int cap_is_fs_cap(int cap)
 502 {
 503         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 504         return !!(CAP_TO_MASK(cap) & __cap_fs_set.cap[CAP_TO_INDEX(cap)]);
 505 }
 506
 507 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
 508 {
 509         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 510         return cap_drop(a, __cap_fs_set);
 511 }
 512
 513 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
 514                                             const kernel_cap_t permitted)
 515 {
 516         const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 517         return cap_combine(a,
 518                            cap_intersect(permitted, __cap_fs_set));
 519 }
 520
 521 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
 522 {
 523         const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
 524         return cap_drop(a, __cap_fs_set);
 525 }
 526
 527 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
 528                                               const kernel_cap_t permitted)
 529 {
 530         const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
 531         return cap_combine(a,
 532                            cap_intersect(permitted, __cap_nfsd_set));
 533 }
 534
 535 extern const kernel_cap_t __cap_empty_set;
 536 extern const kernel_cap_t __cap_full_set;
 537 extern const kernel_cap_t __cap_init_eff_set;
 538
 539 /**
 540  * has_capability - Determine if a task has a superior capability available
 541  * @t: The task in question
 542  * @cap: The capability to be tested for
 543  *
 544  * Return true if the specified task has the given superior capability
 545  * currently in effect, false if not.
 546  *
 547  * Note that this does not set PF_SUPERPRIV on the task.
 548  */
 549 #define has_capability(t, cap) (security_real_capable((t), (cap)) == 0)
 550
 551 /**
 552  * has_capability_noaudit - Determine if a task has a superior capability available (unaudited)
 553  * @t: The task in question
 554  * @cap: The capability to be tested for
 555  *
 556  * Return true if the specified task has the given superior capability
 557  * currently in effect, false if not, but don't write an audit message for the
 558  * check.
 559  *
 560  * Note that this does not set PF_SUPERPRIV on the task.
 561  */
 562 #define has_capability_noaudit(t, cap) \
 563         (security_real_capable_noaudit((t), (cap)) == 0)
 564
 565 extern int capable(int cap);
 566
 567 /* audit system wants to get cap info from files as well */
 568 struct dentry;
 569 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
 570
 571 #endif /* __KERNEL__ */
 572
 573 #endif /* !_LINUX_CAPABILITY_H */