xref: /linux/include/net/netlabel.h (revision 63c41688743760631188cf0f4ae986a6793ccb0a)
1 /*
2  * NetLabel System
3  *
4  * The NetLabel system manages static and dynamic label mappings for network
5  * protocols such as CIPSO and RIPSO.
6  *
7  * Author: Paul Moore <paul.moore@hp.com>
8  *
9  */
10 
11 /*
12  * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
13  *
14  * This program is free software;  you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2 of the License, or
17  * (at your option) any later version.
18  *
19  * This program is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY;  without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
22  * the GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with this program;  if not, write to the Free Software
26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
27  *
28  */
29 
30 #ifndef _NETLABEL_H
31 #define _NETLABEL_H
32 
33 #include <linux/types.h>
34 #include <linux/net.h>
35 #include <linux/skbuff.h>
36 #include <net/netlink.h>
37 #include <asm/atomic.h>
38 
39 struct cipso_v4_doi;
40 
41 /*
42  * NetLabel - A management interface for maintaining network packet label
43  *            mapping tables for explicit packet labling protocols.
44  *
45  * Network protocols such as CIPSO and RIPSO require a label translation layer
46  * to convert the label on the packet into something meaningful on the host
47  * machine.  In the current Linux implementation these mapping tables live
48  * inside the kernel; NetLabel provides a mechanism for user space applications
49  * to manage these mapping tables.
50  *
51  * NetLabel makes use of the Generic NETLINK mechanism as a transport layer to
52  * send messages between kernel and user space.  The general format of a
53  * NetLabel message is shown below:
54  *
55  *  +-----------------+-------------------+--------- --- -- -
56  *  | struct nlmsghdr | struct genlmsghdr | payload
57  *  +-----------------+-------------------+--------- --- -- -
58  *
59  * The 'nlmsghdr' and 'genlmsghdr' structs should be dealt with like normal.
60  * The payload is dependent on the subsystem specified in the
61  * 'nlmsghdr->nlmsg_type' and should be defined below, supporting functions
62  * should be defined in the corresponding net/netlabel/netlabel_<subsys>.h|c
63  * file.  All of the fields in the NetLabel payload are NETLINK attributes, see
64  * the include/net/netlink.h file for more information on NETLINK attributes.
65  *
66  */
67 
68 /*
69  * NetLabel NETLINK protocol
70  */
71 
72 /* NetLabel NETLINK protocol version
73  *  1: initial version
74  *  2: added static labels for unlabeled connections
75  *  3: network selectors added to the NetLabel/LSM domain mapping
76  */
77 #define NETLBL_PROTO_VERSION            3
78 
79 /* NetLabel NETLINK types/families */
80 #define NETLBL_NLTYPE_NONE              0
81 #define NETLBL_NLTYPE_MGMT              1
82 #define NETLBL_NLTYPE_MGMT_NAME         "NLBL_MGMT"
83 #define NETLBL_NLTYPE_RIPSO             2
84 #define NETLBL_NLTYPE_RIPSO_NAME        "NLBL_RIPSO"
85 #define NETLBL_NLTYPE_CIPSOV4           3
86 #define NETLBL_NLTYPE_CIPSOV4_NAME      "NLBL_CIPSOv4"
87 #define NETLBL_NLTYPE_CIPSOV6           4
88 #define NETLBL_NLTYPE_CIPSOV6_NAME      "NLBL_CIPSOv6"
89 #define NETLBL_NLTYPE_UNLABELED         5
90 #define NETLBL_NLTYPE_UNLABELED_NAME    "NLBL_UNLBL"
91 #define NETLBL_NLTYPE_ADDRSELECT        6
92 #define NETLBL_NLTYPE_ADDRSELECT_NAME   "NLBL_ADRSEL"
93 
94 /*
95  * NetLabel - Kernel API for accessing the network packet label mappings.
96  *
97  * The following functions are provided for use by other kernel modules,
98  * specifically kernel LSM modules, to provide a consistent, transparent API
99  * for dealing with explicit packet labeling protocols such as CIPSO and
100  * RIPSO.  The functions defined here are implemented in the
101  * net/netlabel/netlabel_kapi.c file.
102  *
103  */
104 
105 /* NetLabel audit information */
106 struct netlbl_audit {
107 	u32 secid;
108 	uid_t loginuid;
109 	u32 sessionid;
110 };
111 
112 /*
113  * LSM security attributes
114  */
115 
116 /**
117  * struct netlbl_lsm_cache - NetLabel LSM security attribute cache
118  * @refcount: atomic reference counter
119  * @free: LSM supplied function to free the cache data
120  * @data: LSM supplied cache data
121  *
122  * Description:
123  * This structure is provided for LSMs which wish to make use of the NetLabel
124  * caching mechanism to store LSM specific data/attributes in the NetLabel
125  * cache.  If the LSM has to perform a lot of translation from the NetLabel
126  * security attributes into it's own internal representation then the cache
127  * mechanism can provide a way to eliminate some or all of that translation
128  * overhead on a cache hit.
129  *
130  */
131 struct netlbl_lsm_cache {
132 	atomic_t refcount;
133 	void (*free) (const void *data);
134 	void *data;
135 };
136 
137 /**
138  * struct netlbl_lsm_secattr_catmap - NetLabel LSM secattr category bitmap
139  * @startbit: the value of the lowest order bit in the bitmap
140  * @bitmap: the category bitmap
141  * @next: pointer to the next bitmap "node" or NULL
142  *
143  * Description:
144  * This structure is used to represent category bitmaps.  Due to the large
145  * number of categories supported by most labeling protocols it is not
146  * practical to transfer a full bitmap internally so NetLabel adopts a sparse
147  * bitmap structure modeled after SELinux's ebitmap structure.
148  * The catmap bitmap field MUST be a power of two in length and large
149  * enough to hold at least 240 bits.  Special care (i.e. check the code!)
150  * should be used when changing these values as the LSM implementation
151  * probably has functions which rely on the sizes of these types to speed
152  * processing.
153  *
154  */
155 #define NETLBL_CATMAP_MAPTYPE           u64
156 #define NETLBL_CATMAP_MAPCNT            4
157 #define NETLBL_CATMAP_MAPSIZE           (sizeof(NETLBL_CATMAP_MAPTYPE) * 8)
158 #define NETLBL_CATMAP_SIZE              (NETLBL_CATMAP_MAPSIZE * \
159 					 NETLBL_CATMAP_MAPCNT)
160 #define NETLBL_CATMAP_BIT               (NETLBL_CATMAP_MAPTYPE)0x01
161 struct netlbl_lsm_secattr_catmap {
162 	u32 startbit;
163 	NETLBL_CATMAP_MAPTYPE bitmap[NETLBL_CATMAP_MAPCNT];
164 	struct netlbl_lsm_secattr_catmap *next;
165 };
166 
167 /**
168  * struct netlbl_lsm_secattr - NetLabel LSM security attributes
169  * @flags: indicate structure attributes, see NETLBL_SECATTR_*
170  * @type: indicate the NLTYPE of the attributes
171  * @domain: the NetLabel LSM domain
172  * @cache: NetLabel LSM specific cache
173  * @attr.mls: MLS sensitivity label
174  * @attr.mls.cat: MLS category bitmap
175  * @attr.mls.lvl: MLS sensitivity level
176  * @attr.secid: LSM specific secid token
177  *
178  * Description:
179  * This structure is used to pass security attributes between NetLabel and the
180  * LSM modules.  The flags field is used to specify which fields within the
181  * struct are valid and valid values can be created by bitwise OR'ing the
182  * NETLBL_SECATTR_* defines.  The domain field is typically set by the LSM to
183  * specify domain specific configuration settings and is not usually used by
184  * NetLabel itself when returning security attributes to the LSM.
185  *
186  */
187 struct netlbl_lsm_secattr {
188 	u32 flags;
189 	/* bitmap values for 'flags' */
190 #define NETLBL_SECATTR_NONE             0x00000000
191 #define NETLBL_SECATTR_DOMAIN           0x00000001
192 #define NETLBL_SECATTR_DOMAIN_CPY       (NETLBL_SECATTR_DOMAIN | \
193 					 NETLBL_SECATTR_FREE_DOMAIN)
194 #define NETLBL_SECATTR_CACHE            0x00000002
195 #define NETLBL_SECATTR_MLS_LVL          0x00000004
196 #define NETLBL_SECATTR_MLS_CAT          0x00000008
197 #define NETLBL_SECATTR_SECID            0x00000010
198 	/* bitmap meta-values for 'flags' */
199 #define NETLBL_SECATTR_FREE_DOMAIN      0x01000000
200 #define NETLBL_SECATTR_CACHEABLE        (NETLBL_SECATTR_MLS_LVL | \
201 					 NETLBL_SECATTR_MLS_CAT | \
202 					 NETLBL_SECATTR_SECID)
203 	u32 type;
204 	char *domain;
205 	struct netlbl_lsm_cache *cache;
206 	union {
207 		struct {
208 			struct netlbl_lsm_secattr_catmap *cat;
209 			u32 lvl;
210 		} mls;
211 		u32 secid;
212 	} attr;
213 };
214 
215 /*
216  * LSM security attribute operations (inline)
217  */
218 
219 /**
220  * netlbl_secattr_cache_alloc - Allocate and initialize a secattr cache
221  * @flags: the memory allocation flags
222  *
223  * Description:
224  * Allocate and initialize a netlbl_lsm_cache structure.  Returns a pointer
225  * on success, NULL on failure.
226  *
227  */
228 static inline struct netlbl_lsm_cache *netlbl_secattr_cache_alloc(gfp_t flags)
229 {
230 	struct netlbl_lsm_cache *cache;
231 
232 	cache = kzalloc(sizeof(*cache), flags);
233 	if (cache)
234 		atomic_set(&cache->refcount, 1);
235 	return cache;
236 }
237 
238 /**
239  * netlbl_secattr_cache_free - Frees a netlbl_lsm_cache struct
240  * @cache: the struct to free
241  *
242  * Description:
243  * Frees @secattr including all of the internal buffers.
244  *
245  */
246 static inline void netlbl_secattr_cache_free(struct netlbl_lsm_cache *cache)
247 {
248 	if (!atomic_dec_and_test(&cache->refcount))
249 		return;
250 
251 	if (cache->free)
252 		cache->free(cache->data);
253 	kfree(cache);
254 }
255 
256 /**
257  * netlbl_secattr_catmap_alloc - Allocate a LSM secattr catmap
258  * @flags: memory allocation flags
259  *
260  * Description:
261  * Allocate memory for a LSM secattr catmap, returns a pointer on success, NULL
262  * on failure.
263  *
264  */
265 static inline struct netlbl_lsm_secattr_catmap *netlbl_secattr_catmap_alloc(
266 	                                                           gfp_t flags)
267 {
268 	return kzalloc(sizeof(struct netlbl_lsm_secattr_catmap), flags);
269 }
270 
271 /**
272  * netlbl_secattr_catmap_free - Free a LSM secattr catmap
273  * @catmap: the category bitmap
274  *
275  * Description:
276  * Free a LSM secattr catmap.
277  *
278  */
279 static inline void netlbl_secattr_catmap_free(
280 	                              struct netlbl_lsm_secattr_catmap *catmap)
281 {
282 	struct netlbl_lsm_secattr_catmap *iter;
283 
284 	do {
285 		iter = catmap;
286 		catmap = catmap->next;
287 		kfree(iter);
288 	} while (catmap);
289 }
290 
291 /**
292  * netlbl_secattr_init - Initialize a netlbl_lsm_secattr struct
293  * @secattr: the struct to initialize
294  *
295  * Description:
296  * Initialize an already allocated netlbl_lsm_secattr struct.
297  *
298  */
299 static inline void netlbl_secattr_init(struct netlbl_lsm_secattr *secattr)
300 {
301 	memset(secattr, 0, sizeof(*secattr));
302 }
303 
304 /**
305  * netlbl_secattr_destroy - Clears a netlbl_lsm_secattr struct
306  * @secattr: the struct to clear
307  *
308  * Description:
309  * Destroys the @secattr struct, including freeing all of the internal buffers.
310  * The struct must be reset with a call to netlbl_secattr_init() before reuse.
311  *
312  */
313 static inline void netlbl_secattr_destroy(struct netlbl_lsm_secattr *secattr)
314 {
315 	if (secattr->flags & NETLBL_SECATTR_FREE_DOMAIN)
316 		kfree(secattr->domain);
317 	if (secattr->flags & NETLBL_SECATTR_CACHE)
318 		netlbl_secattr_cache_free(secattr->cache);
319 	if (secattr->flags & NETLBL_SECATTR_MLS_CAT)
320 		netlbl_secattr_catmap_free(secattr->attr.mls.cat);
321 }
322 
323 /**
324  * netlbl_secattr_alloc - Allocate and initialize a netlbl_lsm_secattr struct
325  * @flags: the memory allocation flags
326  *
327  * Description:
328  * Allocate and initialize a netlbl_lsm_secattr struct.  Returns a valid
329  * pointer on success, or NULL on failure.
330  *
331  */
332 static inline struct netlbl_lsm_secattr *netlbl_secattr_alloc(gfp_t flags)
333 {
334 	return kzalloc(sizeof(struct netlbl_lsm_secattr), flags);
335 }
336 
337 /**
338  * netlbl_secattr_free - Frees a netlbl_lsm_secattr struct
339  * @secattr: the struct to free
340  *
341  * Description:
342  * Frees @secattr including all of the internal buffers.
343  *
344  */
345 static inline void netlbl_secattr_free(struct netlbl_lsm_secattr *secattr)
346 {
347 	netlbl_secattr_destroy(secattr);
348 	kfree(secattr);
349 }
350 
351 #ifdef CONFIG_NETLABEL
352 /*
353  * LSM configuration operations
354  */
355 int netlbl_cfg_map_del(const char *domain, struct netlbl_audit *audit_info);
356 int netlbl_cfg_unlbl_add_map(const char *domain,
357 			     struct netlbl_audit *audit_info);
358 int netlbl_cfg_cipsov4_add_map(struct cipso_v4_doi *doi_def,
359 			       const char *domain,
360 			       struct netlbl_audit *audit_info);
361 
362 /*
363  * LSM security attribute operations
364  */
365 int netlbl_secattr_catmap_walk(struct netlbl_lsm_secattr_catmap *catmap,
366 			       u32 offset);
367 int netlbl_secattr_catmap_walk_rng(struct netlbl_lsm_secattr_catmap *catmap,
368 				   u32 offset);
369 int netlbl_secattr_catmap_setbit(struct netlbl_lsm_secattr_catmap *catmap,
370 				 u32 bit,
371 				 gfp_t flags);
372 int netlbl_secattr_catmap_setrng(struct netlbl_lsm_secattr_catmap *catmap,
373 				 u32 start,
374 				 u32 end,
375 				 gfp_t flags);
376 
377 /*
378  * LSM protocol operations (NetLabel LSM/kernel API)
379  */
380 int netlbl_enabled(void);
381 int netlbl_sock_setattr(struct sock *sk,
382 			const struct netlbl_lsm_secattr *secattr);
383 int netlbl_sock_getattr(struct sock *sk,
384 			struct netlbl_lsm_secattr *secattr);
385 int netlbl_skbuff_getattr(const struct sk_buff *skb,
386 			  u16 family,
387 			  struct netlbl_lsm_secattr *secattr);
388 void netlbl_skbuff_err(struct sk_buff *skb, int error, int gateway);
389 
390 /*
391  * LSM label mapping cache operations
392  */
393 void netlbl_cache_invalidate(void);
394 int netlbl_cache_add(const struct sk_buff *skb,
395 		     const struct netlbl_lsm_secattr *secattr);
396 #else
397 static inline int netlbl_cfg_map_del(const char *domain,
398 				     struct netlbl_audit *audit_info)
399 {
400 	return -ENOSYS;
401 }
402 static inline int netlbl_cfg_unlbl_add_map(const char *domain,
403 					   struct netlbl_audit *audit_info)
404 {
405 	return -ENOSYS;
406 }
407 static inline int netlbl_cfg_cipsov4_add_map(struct cipso_v4_doi *doi_def,
408 					     const char *domain,
409 					     struct netlbl_audit *audit_info)
410 {
411 	return -ENOSYS;
412 }
413 static inline int netlbl_secattr_catmap_walk(
414 	                              struct netlbl_lsm_secattr_catmap *catmap,
415 				      u32 offset)
416 {
417 	return -ENOENT;
418 }
419 static inline int netlbl_secattr_catmap_walk_rng(
420 				      struct netlbl_lsm_secattr_catmap *catmap,
421 				      u32 offset)
422 {
423 	return -ENOENT;
424 }
425 static inline int netlbl_secattr_catmap_setbit(
426 	                              struct netlbl_lsm_secattr_catmap *catmap,
427 				      u32 bit,
428 				      gfp_t flags)
429 {
430 	return 0;
431 }
432 static inline int netlbl_secattr_catmap_setrng(
433 	                              struct netlbl_lsm_secattr_catmap *catmap,
434 				      u32 start,
435 				      u32 end,
436 				      gfp_t flags)
437 {
438 	return 0;
439 }
440 static inline int netlbl_enabled(void)
441 {
442 	return 0;
443 }
444 static inline int netlbl_sock_setattr(struct sock *sk,
445 				     const struct netlbl_lsm_secattr *secattr)
446 {
447 	return -ENOSYS;
448 }
449 static inline int netlbl_sock_getattr(struct sock *sk,
450 				      struct netlbl_lsm_secattr *secattr)
451 {
452 	return -ENOSYS;
453 }
454 static inline int netlbl_skbuff_getattr(const struct sk_buff *skb,
455 					u16 family,
456 					struct netlbl_lsm_secattr *secattr)
457 {
458 	return -ENOSYS;
459 }
460 static inline void netlbl_skbuff_err(struct sk_buff *skb,
461 				     int error,
462 				     int gateway)
463 {
464 	return;
465 }
466 static inline void netlbl_cache_invalidate(void)
467 {
468 	return;
469 }
470 static inline int netlbl_cache_add(const struct sk_buff *skb,
471 				   const struct netlbl_lsm_secattr *secattr)
472 {
473 	return 0;
474 }
475 #endif /* CONFIG_NETLABEL */
476 
477 #endif /* _NETLABEL_H */
478