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